ChapterPDF Available

Knee Pain in Adults & Adolescents, Diagnosis and Treatment



Content may be subject to copyright.
Chapter 8
© 2012 Hing et al., licensee InTech. This is an open access chapter distributed under the terms of the
Creative Commons Attribution License (, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Knee Pain in Adults & Adolescents, Diagnosis
and Treatment
Sherif Hosny, W. McClatchie, Nidhi Sofat and Caroline B. Hing
Additional information is available at the end of the chapter
1. Introduction
Knee pain is a common symptom affecting both children and adults [1]. Assessment of pain
is important in order to determine the aetiology of the underlying condition which can be
investigated with mechanistic studies further in order to assess the response to treatment
We performed a literature search to identify pertinent review articles investigating advances
in knee pain diagnosis and management in humans using the MeSH terms and Boolean
operators ‘knee’ AND ‘pain’. We identified 11928 relevant articles and limited our search to
review articles on humans in English. The structure of the chapter is divided into
subheadings covering definition, incidence, aetiology, classification, diagnosis and
management. Within each subheading, further sections address the use of novel imaging to
quantify disease progression, operative and non-operative management. A separate section
will outline the causes and treatment of knee pain in adolescents. A further section outlines
future advances in diagnosis and management.
2. Definition
Knee pain is broadly divided into tibiofemoral and anterior knee pain (AKP). Knee pain can
be referred from the hip or present as part of radiculopathy. AKP can refer to a number of
symptoms. In the past the terms ‘chondromalacia patellae’ and ‘patellofemoral pain’ have
been used loosely to describe such symptoms. This is to be avoided, as whilst both
conditions are recognised, they may not be the cause of the pain. The term ‘anterior knee
pain’ may be used when no specific diagnosis has been made [2].
Jackson et al (2001) divided the causes of AKP broadly into two groups [1]. The first group
includes focal lesions which can be identified clinically or radiologically, and is described as
Pain in Perspective
distinct. This includes overuse syndromes, trauma related lesions, dysplasias, tumours, and
iatrogenic lesions. The second group is described as obscure and includes types of knee pain
that are dynamic, or are more difficult to define. The symptoms may vary widely between
individuals with the same clinical findings. This includes patellar maltracking,
chondromalacia, idiopathic pain, reflex sympathetic dystrophy and psychogenic pain.
Tibiofemoral knee pain can be described as acute or chronic. Acute symptoms are often
mechanical in nature and due to a recent injury. Pain may arise from acute injury to the
menisci, and / or to the ligamentous stabilisers of the knee. Resultant alteration to the
biomechanics of the joint can lead to degenerative change and associated symptoms.
Chronic knee pain is commonly due to arthritic change. Osteoarthritis (OA) is the most
common and is a degenerative condition caused by focal cartilage loss. It is often described
according to conventional radiological findings as described by Kellgren and Lawrence [3].
These include osteophyte formation, narrowing of joint space, sclerosis of subchondral bone
and cyst formation. Utilising these changes as a guide, five grades were used to describe
OA: 1. None, 2. doubtful, 3. minimal, 4. moderate and 5. Severe [2]. Ahlbäck [4] described
the radiographic changes in terms of joint space narrowing (Grades I-II) and bone attrition
(Grades III – V). The American College of Rheumatology’s classification of OA mentions
knee pain occurring over most days of the previous month, crepitus on joint movement and
morning stiffness. The World Health Organisation (WHO) Global Burden of Disease defined
OA of the knee as a combination of these clinical criteria in the presence of defined
radiological changes [5].
Rheumatoid arthritis (RA) is a destructive chronic inflammatory condition that affects the
small joints of the hands and feet, along with larger joints. Symptoms initially include pain
and swelling as the synovial lining of the joint is inflamed. Chronic progression of the
disease leads to cartilage erosion and joint laxity resulting in deformity. Conversely, crystal
arthropathy results from the deposition of monosodium urate (gout) or calcium
pyrophosphate (pseudogout) within the knee joint. The precipitation of these crystal
induces an inflammatory reaction within the joint.
3. Incidence / prevalence
There is some difficulty in establishing the true incidence of knee pain, as the actual
definition of knee pain varies according to its cause. Most data available relates to arthritis,
as it is a chronic disabling condition, with a significant impact on health. In a cross sectional
study of 3341 residents aged over 65 in Oxfordshire, United Kingdom, the prevalence of
knee pain was 32.6%, using the SF-36 questionnaire [6].
There is a paucity of reports on the prevalence of knee pain from developed countries, Haq
2011 [7] reported global findings from the Community Orientated Program for Control Of
Rheumatic Disorders (COPCORD). Wide variation in knee pain was seen both between
rural and urban settings and also between countries. In all studies the prevalence of knee
pain was greater in women than in men. Rural Iran had the highest recorded prevalence of
39.2% across the population.
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
A cohort study by Ingham et 2011 [8] found the risk of knee pain for people over the age of
forty in the United Kingdom was 32/1000 person-years (3.2%) or a 12-year cumulative
incidence of knee pain of 34.4% (32% for men, 35% for women). There was an increasing
trend observed with increasing body mass index. The incidence in a Bangladeshi rural
community recorded through COPCORD was only 6.5%.
The incidence of reported knee pain in older patients is increasing, yet this does not always
correlate with radiographic changes associated with arthritis. Nguyen et al 1999 [9] reported
on three separate time periods measured by the Framingham Osteoarthritis Study in the US.
This showed the prevalence of knee pain in men between 2002 and 2005 was 32.9%, and
27.7% in women. An increasing trend in reported knee pain was observed over three
decades in the over 70 age group. Surprisingly this trend did not correlate with an
increasing body mass index (BMI), confounding the observation seen elsewhere that
increased BMI correlates with an increased incidence of OA.
Symptomatic OA in younger patients was recorded by the 1987 Framingham study. Five
percent of those over 26 years of age had pain along with radiological changes, with 6.7% of
those over 45 years of age reporting the same symptoms. McAlindon et al 1992 [10] reported
the prevalence of symptomatic isolated patellofemoral osteoarthritis of 11% in males over 55
years, and 24% in women over 55 years. In asymptomatic patients 3.8% of both men and
women had isolated radiographic patellofemoral OA.
Jarvholm et al 2008 [11] reported that occupational factors are important risk factors for
developing OA of the knee. In a population of male construction workers in Sweden the
relative risk for surgically treated OA of the knee was 4.7. Those with more labour intensive
roles had an increased risk. In a study of Finnish forestry workers the incidence of knee pain
was 10% over a one year period [12]. Increased age, being overweight and knee straining
activities all increased the likelihood of developing pain. The persistence of symptoms was
associated with increased age and job dissatisfaction.
It is difficult to establish the exact incidence of knee pain specifically due to RA, although
there appears to be a decreasing trend in knee arthroplasty for these patients. In a study of
Californian adults over two decades Louie et al 2010 [13] noted that the demand for knee
arthroplasty decreased in younger patients, and paralleled the general population
requirements in older patients. The introduction of the use of methotrexate in the 1970s, and
more recently the use of Tumour Necrosis Factor α has been attributed to milder forms of
the disease and the slowing of radiographic deterioration [14].
4. Aetiology
In order to understand the aetiology of anterior knee pain it is vital to appreciate the
biomechanical factors governing normal loading conditions. The weight distribution
through the knee is governed by the mechanical axis of the lower limb. Usually this passes
through or just medial to the centre of the knee joint in the coronal plane. Deviation of the
mechanical axis away from this leads to increased contact stresses at the joint surface.
Pain in Perspective
Morrison et al 1970 [15] showed that the mean maximum joint force at the knee was 3.03
times body weight (range 2.06-4.0) during normal gait cycle. During stance phase the centre
of pressure passed through the medial side of the joint, indicating that most of the joint force
is centred there.
Understanding the movement of the tibiofemoral joint is aided by magnetic resonance
imaging (MRI) studies [16]. As the knee flexes the femoral condyles roll backwards and slide
on the tibia. This mechanism, along with the increasing arc of curvature of the posterior
aspect of the femoral condyles, allows increased flexion of the knee. Dynamic studies have
shown the lateral femoral condyle to have increased backward movement of the contact
area relative to the medial femoral condyle. This in effect produces rotation of the tibia
internally as the knee flexes.
The patella forms part of the extensor mechanism of the knee and has thick articular
cartilage to withstand the joint reaction force. It allows an increased lever arm of the
extensor mechanism which enhances its strength. The medial and lateral articular facets
enter the trochlear groove of the femur at 20° of flexion and maximum contact is achieved
with the femur at 45°. The peak contact pressures within the patellofemoral joint occur
between 60° and 90° of flexion. This range corresponds to the areas where degenerative
lesions are most commonly seen. In the simple action of rising from a chair the force going
through the patellar tendon can reach 3.6 times body weight [17]. The joint reaction force
can reach 385 N during walking, and reach 5972 N when landing from a jump [18].
Hip pathology, from childhood through to adulthood may present as femoral or knee pain
and must be eliminated as a cause of symptoms, as does neurological pain due to proximal
nerve lesions. Pain is transmitted from nociceptors distributed around the knee. Articular
cartilage does not contain nerve endings, therefore damage to this layer is not a direct
source of pain. Nociceptor fibres, including those transmitting substance P, have been found
to be widely distributed in the soft tissues around the knee joint [19], including the
retinaculum, synovium and fat pad. Higher concentrations have been found immediately
surrounding blood vessels, suggesting a role in vascular tone and extravasation of fluid
leading swelling and effusion. Biedert et al 1992 [20] found increased concentration of type IVa
nerve fibres were found in the retinaculum, patellar ligament and pes anserinus. Gronsblad
1985 [21] reported the presence of Substance P-immunofluorescent nerves and enkephalin-
immunofluorescent nerves in the synovial membrane and the menisci. Dye 1998 [22]
underwent arthroscopy of his own knees while conscious, and identified anterior synovium,
fat pad and joint capsule as the most sensitive areas to pain. The insertion of the cruciate
tendons provokes some pain, as did peripheral meniscus. The articular surface of the patella
did not evoke significant discomfort. Hochmann et 2011 [7] looked at the contribution of
neuropathic pain in patients with chronic knee pain. Having excluded those with pre-existing
neurological conditions, 19% reported symptoms consistent with neuropathic pain.
Arthritic pain is commonly described as a dull ache, which is made worse on movement
after a period of rest. While the loss of articular cartilage in osteoarthritis is not a direct
source of pain, the resultant changes to the subchondral bone show radiological and
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
histological changes. The loss of the articular cartilage changes the stresses on the
underlying subchondral bone, which itself has pain receptors. Subchondral bone may react
to increasing shearing forces by becoming reactive and sclerotic [23]. Bone scintigraphy
studies have shown an increase in delayed phase tracer in the tibiofemoral compartment in
of patients reporting knee pain [24]. This is likely to represent increased metabolic bone
turnover in response to the changing physical stress environment of the bone. The increased
tracer uptake has been shown to have a sixfold increased risk of progression to OA [25].
The increasing use of MRI in evaluating knee pain has allowed detection of histological
changes not previously seen on plain radiographs. Bone marrow oedema, or bone marrow
lesions (BML), appear on MRI as increased signal on fat suppressed T2 weighted images.
The presence of BMLs has been associated with an increase in reported pain, and have a
strong association with progression to radiographic changes of OA. This may help explain
the degree of symptoms in patients with only mild radiographic changes associated with
arthritis. McAlindon 1992 [10] showed that only 54% of a cohort of patients over 55 years
old with knee pain had radiographic evidence of OA. Conversely 17% of asymptomatic
patients had radiographic changes consistent with OA, suggesting that radiographic
changes alone do not fully explain the symptoms reported. In the presence of OA, Hill 2001
et al [26] found that the degree of synovial thickening and presence of an effusion correlated
with the level of pain reported. It is also likely that individuals differ in perception of pain.
Valdes et al 2011 [27] has reported an amino acid variant in the TRPV1 gene is associated
with lower pain thresholds in radiographic OA.
Rheumatoid arthritis (RA) is a destructive inflammatory arthropathy that affects the small
joints of the hands and feet, along with the large joints. An autoimmune reaction targets the
synovial lining of the joint, leading to destruction of the cartilage and changes to the soft
tissue structures around the knee causing deformity. The altered biomechanics of the joint
accelerate the degenerative changes of the cartilage. Without appropriate pharmacological
treatment or surgical intervention it can lead to profound disability and pain. The evolution
of disease modifying anti-rheumatoid drugs (DMARDs) has had a significant effect on the
number of patients requiring surgery [13].
Gout and pseudogout are caused by the deposition of crystals within the joint. The crystals
induce the release of mediators resulting in inflammation. Whilst the reaction is usually self-
limiting, its course can be shortened with use of anti-inflammatory medication. There has
been increased incidence in gout noted over the last three decades [28]. Although genetic
factors feature, it is also thought to be related to diet, lifestyle and increased longevity. Gout
is the result of deposition of monosodium urate crystals within the joint. Urate is produced
in the metabolism of purine, and is excreted in urine. If serum urate levels are elevated'
monosodium urate levels in the extracellular fluid become saturated and crystals develop.
Acute soft tissue injuries around the knee cause pain and a variable amount of swelling. The
anterior cruciate ligament (ACL) is supplied by the middle genicular artery. Acute rupture of
the ligament activates nociceptor fibres, and the ensuing haemarthrosis stretches the joint
capsule. While the initial pain subsides, the consequence of the altered biomechanics of the
Pain in Perspective
knee leads to chronic symptoms. Lohmander 2004 [29] reported that 12 years after injury of the
ACL in young female athletes 75% reported significant knee pain and 42% had symptomatic
radiographic knee osteoarthritis, whether a reconstruction was carried out or not.
Meniscal injuries can also be acutely painful at the time of injury. Proposed sources of pain
include the resulting synovitis or distortion of the capsule from the meniscal tear. Mine et al
2000 [30] reported the presence of nociceptor fibres, mainly in the more vascular outer third
(the red zone) and also at the anterior and posterior horns. This suggests an additional
source of pain, although it does not fully explain the discomfort experienced from tears in
the avascular inner third (white zone).
Like ACL injuries, meniscal injuries can lead to long term degenerative change.
Berthiaume et al 2005 [31] used serial MRI to show that meniscal injury and volume loss
was associated with an increased risk of degenerative change. Many people with
symptomatic meniscal tears choose to have a partial or total meniscectomy. Roos et al
1998 [32] presented the results of a 21 year follow up study of patients post total open
meniscectomy. The relative risk of developing tibiofemoral OA was 14.0 compared
controls. Currently modern treatment algorithms have been to conserve healthy meniscus
using a minimally invasive approach. Englund et 2004 [33] reported that even with
limited resection the relative risk of radiological OA was 7.0 compared to matched
controls, and 2.7 for symptomatic OA.
Anterior knee pain can occur in both children and adults. Both groups can be difficult to
treat and the exact diagnosis can be elusive. Whilst there are certain terms used to describe
the mechanisms by which the pain occurs, there will be cases where a true diagnosis is
never made. In the past the term chondromalacia patella has been used. This should be
avoided as it falsely attributes a pathological process and may lead to incorrect treatment
and affect patient expectations.
Wear of the articular cartilage in the patellofemoral joint is associated with chronic knee
pain. Like the tibiofemoral compartment not all with radiographic features of arthritis have
symptoms [10]. The cause of the articular wear can be mechanical or inflammatory in
nature. The even distribution of load across the joint avoids stress concentration, the
alignment of the patella is thought to contribute to acute and chronic symptoms. There is
some anatomical variation in the shape of the joint [34], which may predispose the early
degenerative change. Dye et al [35] reports a shift in thinking away from biomechanical
malaligment of the patellofemoral as a cause of acute pain. Instead he proposed that
inflammation of synovium and fat pad along with increased metabolic activity in
subchondral bone have aetiological importance.
5. Knee pain in children & adolescents
There are recognised pathological changes that are unique to the skeletally immature knee
[36]. Overuse of the knee can result in pain that only resolves after a period of rest. This is
due to stress injuries from repetitive use, usually because of increased demands placed on
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
the knee. They are also more common during growth spurts. Once the knee has been
afforded time to recover from such stress then the symptoms usually resolve. The junction
of the patellar ligament at the tibial tuberosity is a common site for such pain. Termed
Osgood Schlatter’s disease, the pain is in response to repeated stress causing mild avulsion
injuries. The natural history is one of spontaneous resolution before adulthood [37]. Sinding-
Larsen-Johannson disease presents as pain at the distal pole of the patella and responds to a
simple non-operative therapy like Osgood Schlatter similar to the treatment of Osgood
Schlatter disease.
5.1. Traction apophysitis
Osgood-Schlatter and Sinding-Larsen-Johansson disease is commonly seen in the male 12-14
age group. Kneeling is painful in Osgood-Schlatter disease and the tibial tubercle is painful
to palpation. There may also be a prominence which is visible on the XR knee lateral. In later
stages the tubercle will have a fragmented appearance due to the separation of the chondro-
osseous fragments [1] Treatment is conservative with reduction in the usually very high
level of activity and simple analgesics (NSAIDS) till the symptoms have subsided.
Quadriceps strengthening is avoided as this increases stresses across tibial tuberosity. This
usually resolves within one to two years although the bony tibial tubercle prominence may
persist. If they remain symptomatic there may be an ossicle in the substance of the tendon
with an associated bursa of which surgical removal can be curative.
Whereas Osgood-Schlatter disease affects the tibial tubercle Sinding-Larsen-Johansson
disease affects the lower pole of the patella. Treatment is the same as that for Osgood-
Schlatter, namely conservative.
Osteochondritis dissecans should be considered as a cause if tibiofemoral and anterior knee
pain. Most commonly affecting the lateral aspect of the medial femoral condyle, its cause
has not been established although repeated trauma and vascular insult are likely to play a
role [37]. A multipartite patella may also cause anterior knee pain, and may be detected on
plain radiograph. Saupe 1943 [38] described three types: inferior pole, lateral patellar
margin, and superolateral pole. Pain usually originates from the junction of the main body
of the patella and the fragment.
Idiopathic anterior knee pain in the adolescent is difficult to treat. The cause has not been
ascertained and prescribed treatments not always successful. The term chondromalacia
patella has occasionally been used in describing such a problem, however this should be
avoided as the term describes chondral changes that are not always present in anterior knee
pain. Nimon et al [39] carried out a 14-20 year follow up on idiopathic anterior knee pain
and determined that no operative intervention provided a better long term outcome than
non-operative treatment.
Tumours should be considered as a cause of continuing knee pain, especially when night
pain is present. There may also be localised swelling and skin changes. Malignant primary
Pain in Perspective
tumours are less common, if there is any doubt as to the diagnosis then at least plain
radiographs in two planes should be sought.
5.2. Classification
Knee pain can present as an acute episode or a more chronic course. It is usually described
by the causative pathology. The common causes of knee pain change with age of the patient,
in children soft tissue and tendon causes are more common while in older adults arthritis is
more prevalent.
Knee pain can be classified according to the affected compartments or structures.
Anatomically the knee is divided into the tibiofemoral joint, medial and lateral, and its
associated soft tissue structures. The patellofemoral joint is described separately, along with
the associated tendinous structures that form the extensor mechanism of the knee.
The tibiofemoral joint contains the weight bearing surfaces of the femur and the tibia. The
medial and lateral menisci are interpositioned between the two and have a role in load
distribution. The anterior and posterior cruciate ligaments and the medial and lateral collateral
ligaments provide stability along with the contents of the posterolateral corner of the knee.
The anterior part of the knee includes the patella, which acts to increase the lever arm of the
extensor mechanism of the knee. The quadriceps insert into the proximal pole and the
patellar ligament (also referred to as patellar tendon) links the inferior pole with the tibial
tuberosity. The infrapatellar far pad lies posterior to the patellar tendon and is richly
Acute episodes may be caused by trauma to the bone, articular surface or soft tissues, but
also include localised inflammation or minor injuries due to overuse. Chronic episodes often
involve degenerative change to the articular surfaces. Arthritis can be idiopathic, or
secondary to trauma. Inflammatory arthritis includes rheumatoid arthritis, gout, reactive
arthritis and septic arthritis.
There is no broad consensus on classification of OA of the knee. Radiological findings have
been described using the definitions of Kellgren and Lawrence. This has been widely used,
including the World Health Organisation (WHO) epidemiological studies. Schiphof 1998
[40] assessed 25 different classification criteria of osteoarthritis which could be broken down
into radiological, clinical, and both radiological and clinical criteria. One reason why a
consensus does not exist is that radiographic findings may not relate to symptoms.
Post 2005 [41] divided anterior knee pain (AKP) into constant pain not activity related, sharp
intermittent pain, and activity related pain. The constant pain may be neurological in nature,
whether from sensory nerve pathology or autonomic nerves. Also included is pain reported
for perceived secondary gain. Sharp intermittent pain usually relates to unstable structures
within the knee or loose bodies. Activity related pain is divided into soft tissue overload
with normal patellar alignment, or articular tissue overload and degenerate changes of the
chondral surface.
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
5.3. Knee pain classification
Anterior knee pain Pain type Distinct/obscure
Patellar tendonitis Activity related Distinct
Bipartitite Patella Intermittent and
Johansson syndrome
Activity related Distinct
Osteochondritis Dissecans Activity related Distinct
Synovial Impingement Intermittent and
Chondromalacia patellae Intermittent and
Patellofemoral osteoarthritis Constant Distinct
Patellar maltracking Activity related Obscure
Excessive lateral pressure syndrome Activity related Obscure
Tibiofemoral knee pain
Tibiofemoral OA Constant
Meniscal tears Intermittent and
Ligamentous injuries Activity related
Table 1. Knee pain classification
6. Diagnosis and management
6.1. Diagnosis
Whilst history, examination and standard radiographic imaging are important in the
determination of the aetiology of knee pain, newer imaging techniques and pain maps can
also supplement the investigation of the causes of knee pain. This section will summarise
pertinent symptoms and signs in the assessment of knee pain as well as describe advances
in pain mapping and imaging.
6.2. Patient history
Several points in the history can yield very important diagnostic information about the
cause of knee pain. Pain on sitting or climbing/descending stairs is often secondary to
patellofemoral aetiology. Pain on squatting often with symptoms of locking or clicking
usually relate to a meniscal tear. ACL tears are often described as a sudden ‘pop’ with
immediate swelling and an inability to continue the activity that preceded it. This is a
pivoting injury and can be without significant contact. Conversely the same symptoms with
a significant contact force may suggest a collateral ligament tear. In both cases acute
Pain in Perspective
swelling will occur. A blow to the anterior tibia such as a dashboard or snowboarding injury
can result in a Posterior cruciate ligament (PCL) tear. A sensation of an unstable knee or
‘giving way’ suggests ligamentous laxity or patellar instability. A history of sharp pain may
be related to synovial impingement or loose bodies within the knee. Aching pain or pain
after activity is thought to be related to inflammatory disorders whereas pain during activity
is associated with structural abnormalities such as patellar subluxation or dislocation [42].
OA knee pain is typically insidious in onset and aggravated by movement and weight
bearing and relieved by rest.
6.3. Patient examination
When examining a patient observation of their gait and stance can give valuable clues to
their diagnosis. Quadriceps circumference if decreased indicates atrophy from inactivity. A
palpable knee effusion is relatively non specific but can suggest a meniscal or ligamentous
injury in the acute setting or arthritis in the chronic setting. Joint line tenderness indicates a
meniscal tear which can also manifest as a block to full extension if big enough (such as a
bucket handle tear). Loose bodies can also cause a locked knee.
Patella apprehension tested by pushing the patella laterally at 20-30° of flexion indicates
subluxation or dislocation. Patella grind and crepitus signify patellofemoral pathology. The
Q-angle as measured from the angle between a line from the anterior superior iliac spine to
the centre of the patella and a line from the centre of the patella to the tibial tubercle is
increased with patella malalignment representing the degree of valgus translational force
exerted upon the patella with quadriceps contraction.
Varus and valgus stress testing will confirm a lateral collateral ligament (LCL) and medial
collateral ligament (MCL) injury respectively. Lachman test will be more sensitive than
anterior draw for an anterior cruciate ligament (ACL) injury. A pivot shift test with the knee
flexed at 20-30° and internal rotation with valgus stress can also signify an ACL tear. The
pivot shift however can only be done under anaesthesia. A posterior draw test is sensitive
for a PCL injury although care must be taken in misinterpreting a positive posterior draw
test as an ACL rupture if the tibia can be translated anteriorly in the anterior draw test.
To test for a posterolateral corner injury an assistant is needed. With the knees stabilised the
feet are externally rotated and the thigh foot angle is compared at both 30 and 90° of knee
flexion. If there is asymmetry of greater than 15° at 30° flexion only this represents an
isolated posterolateral corner (PLC) injury. If asymmetry is present at both 30 and 90° knee
flexion this represents a combined PCL-PLC injury.
6.4. Radiological imaging
Conventional radiography of the knee comprises a standard anteroposterior view and a
lateral view. The lateral view allows assessment of the vertical position of the patella such as
in patella alta (associated with lateral patella dislocation/subluxation, chondromalacia,
patella ligament rupture, and Sinding-Larsen-Johansson) and baja (quadriceps tendon
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
rupture, neuromuscular disorders and achondroplasia). Measurement of patellar tilt on the
lateral radiograph with the knee if full extension is more sensitive for patellofemoral joint
(PFJ) pain and prior dislocation than measures on the axial view [43]. The axial will show
PFJ static alignment. The Insall ratio [44] is used to determine relative patellar height. The
congruence and sulcus angles are indices of patellar subluxation. Trochlear depth may be
measured using the sulcus angle. The congruence angle is a measure of lateral patellar
displacement. The lateral patellofemoral angle on the axial view is a measure of patellar tilt.
Abnormalities of these measurements may represent mal-alignment although they may be
normal in asymptomatic patients when measured in mild degrees of flexion [45]. Computed
tomography (CT) allows axial plane evaluation of the PFJ relationships in varying degrees
of flexion for detecting malalignment. Imaging over the range of 5-30° of flexion is the most
useful for discriminating between normal and abnormal patellar tracking since beyond 30°
the patella centralizes in the trochlear groove. Rapid techniques able to capture images
during active knee motion are described. This is now performed using helical CT which
allows continuous rotation of the X-Ray tube and detectors during active joint motion. From
knee extension to 45° flexion 1 image a second is captured resulting in a total scan time of 10
seconds [46].
Magnetic resonance imaging (MRI) can visualize the components of the extensor mechanism
and show lesions of articular cartilage and menisci, plicae and osteoarthritic change. Static
MR imaging axial sections are obtained with the knee imaged at 4-8 different angle
positions. This can be performed using any MR sequence without motion artifact. The
disadvantage however is that joint kinematics and muscle contraction effects cannot be
assessed. Kinematic MRI using motion triggered or ultrafast imaging techniques can be used
to assess the contribution of associated soft-tissue structures to PFJ function with ultrafast
imaging being less dependent on patient cooperation and can be performed even with
severe patellar pain yielding fewer motion artifacts and better image quality. Kinematic MR
imaging is also superior to axial radiographs in assessing patellar realignment surgery as
significant differences between pre and post operative measurements are better
demonstrated [47]. Overall MR imaging (especially ultrafast sequences) is felt to be superior
to CT imaging in evaluation patellofemoral tracking. Muhle et al [46] feel that it should
always be used in such cases in preference to CT unless the patient has contraindications to
MR imaging. Different MR sequences are appropriate for imaging specific pathologies.
Synovitis is best assessed by gadolinium enhanced MR sequences. Joint effusion is best
detected on fat suppressed PD or T2 weighted FSE sequences. BML are best visualized on
fat suppressed T2 weighted or STIR images. Menisci are typically visualized on sagittal PD
(TE<20) FSE sequences and Ligaments on PD or T2 weighted FSE sequences.
6.5. Functional MRI
How the brain processes noxious stimuli in different disease states has been investigated
using functional MRI (fMRI). This is also to map the cortical location to which the pain is
mapped. fMRI uses a fast MR imaging method for which the image intensity is sensitive to
the variations in magnetic field created in the tissue by the presence of paramagnetic
Pain in Perspective
deoxyhaemoglobin [48]. An increase in blood flow due to increased metabolic activity while
processing a stimulus leads to decreased deoxyhaemoglobin and a small increase in
intensity. Even with a modern 3 Tesla scanner this is only 10% increase in signal. With such
low sensitivity several measurements are needed in individual patients or multiple patient
datasets. Results from fMRI investigations has revealed that central activation of the brain
mediates pain during OA and that non steroidal anti inflammatory drugs (NSAIDs)
therapies may be partially acting via a central mechanism [49]. Furthermore in a recent
paper by Gwilym et al 2009 [50] suggested that in specific groups of patients addressing
central components of central pain processing by fMRI may be important for the treatment
of long term OA pain.
6.6. PET
Positron emission tomography (PET) can be used to create two or three dimensional images
of blood flow or metabolic processes [48]. Studies have shown arthritic pain is also
associated with areas of the brain implicated in affect averse conditioning and motivation as
well as the normal pain perception areas. Such findings have important implications for the
management of patients with long term OA.
The use of fMRI, Positron emission tomography (PET), Single-photon emission computed
tomography (SPECT) and Magnetoencephalography (MEG) are novel imaging modalities
that have helped unravel how central pain pathways in the perception of chronic pain
6.7. Scintigraphy
This is a diagnostic test used in nuclear medicine. Radioisotopes taken internally emit
radiation that is captured by external detectors (gamma cameras) to form a two dimensional
image. Radioisotopes such as technetium-99m-MDP are preferentially taken up by bone and
the specificity can be increased by performing an indium 111-labeled white blood cell test
combined with a Technetium-99m-MDP injection. Conditions that cause increased bone
turnover or inflammation can be diagnosed.
As such bone scanning can be used to detect fractures within 24 hours of the injury. This
initially presents as increased vascularity and delayed scans can show increased uptake for
up to six months after a fracture. Similarly bone bruises or trabecular fractures cause
increased vascularity and uptake and are often associated with ligamentous injuries which
show as bone bruised patterns in the adjacent site of bone attachment. Bone scanning is
sensitive at showing stress fractures. Osteoarthritis causes increased uptake of radio
nucleotide around the articular surface of the bone because of increased bone turnover.
Increased uptake on both sides of a joint is characteristic of osteoarthritis. Bone scanning can
also be helpful in the diagnosis and monitoring of CRPS following treatment [51].
Osteomyelitis shows increased vascularity and increased uptake on a three phase bone scan.
Similarly cellulitis can also be diagnosed on a bone scan. Scintigraphy presents physiological
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
features whereas radiography, CT and MRI all give structural information. In recent years,
however, MRI scanning has largely replaced bone scanning for the diagnosis of localised
knee pain.
6.8. USS
Ultrasound (USS) is a diagnostic imaging technique in the context of orthopaedics to
visualize muscles and tendons tendons, nerves, ligaments, soft tissue masses, and bone
surfaces. Compared to CT and MRI, USS is relatively inexpensive, portable and safe as it
does not use mutagenic ionising radiation [52]. It is however largely operator dependent,
and is unable to evaluate bone and other structures.
Although USS can be used for detection of ligament ruptures and meniscal injuries within
the knee [53,54], this role has largely been superseded with the use of MRI.
Ultrasound is ideally placed for the assessment of tendon lesions, particularly partial and
complete quadriceps rupture and tendinitis of the patellar tendon [55]. USS can also
evaluate muscle injury and differentiate between partial and complete tears [54]. It is also
very valuable in differentiating between swellings around the knee such as popliteal cysts
and other local swellings including aneurysm, nerve sheath tumour and ganglia [56].
Joint effusions and bursae are easily detected by ultrasound. Ultrasound guided aspiration
of bursitis can be carried out if necessary.
6.9. Arthroscopy
Arthroscopy is useful for direct visualization of bone, cartilage and soft tissue. Despite
advances in non-invasive imaging techniques it is still considered the most reliable method for
assessing patellar position and tracking. CT and MRI however, still provide useful augments.
6.10. Bone marrow lesions and osteoarthritis progression
Bone scans of patients with OA have shown increased uptake of tracer in the subchondral
bone signifying increased turnover [25]. This was found to be associated with increased joint
pain and increased risk of progression to radiographic OA. Similarly this has been
demonstrated on MRI as increased signal in the marrow on fat suppressed T2 weighted
images and has been dubbed bone marrow lesions [57]. Histological these manifest as bone
marrow necrosis, trabecular abnormalities and bone marrow fibrosis and oedema [58]. It has
also been reported that in patients with radiographic OA those who also had BM oedema
lesions more often had knee pain than those without [59]. BMLs are localized to the
subchondral bone. As the subchondral bone is innervated BML are thought to be a potential
source of pain. Recent longitudinal studies have demonstrated that bone marrow lesions
powerfully predict risk of local structural deterioration in OA knees. The risk of medial
progression of OA within the knee was increased sixfold if there were medial BMLs.
Similarly the risk was increased laterally if there were lesions laterally. Furthermore varus
Pain in Perspective
knees had a very high prevalence of medial bone marrow lesions whereas valgus knees had
preferential lateral lesions. What is not clear however is whether the limb malalignment
itself causes the progression of OA and development of the BML or whether OA
progression is a consequence of the presence of BMLs [25]. Tanamas et al [60] found that the
relationship between BML presence and cartilage change was independent of tibiofemoral
alignment. Furthermore as there is no treatment for BMLs currently there is no justification
for the routine use of MRI in assessing OA patients particularly as it is not clear if the lesions
themselves cause structural damage or are a consequence of malalignment.
Figure 1. Coronal STIR MRI showing subchondral bone oedema and synovitis
Until recently there has been much focus on articular cartilage in assessing OA severity.
There is conflicting data about whether cartilage damage correlates with pain. And recent
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
studies have tied to shift the emphasis to other pathological events such as BML and
synovial effusion/synovitis in understanding the cause of OA pain. The clinical implication
of BML is not clear. It is present in 78% of patients with knee OA with pain and in 30% of
patients in knee OA without pain [59]. BML is not pathognomonic of knee OA but its
association is intriguing and not fully understood. This only highlights the need for more
research into the matter. It is becoming more evident that pain from OA is multifactorial and
that research into such new fields will help predict disease progression and alter improve
Pain in Perspective
Figure 2. Coronal PD FS images showing severe OA with complete cartilage loss and subarticular tibial
plateau bone oedema
7. Anterior knee pain
7.1. Patella tendon tendinitis
Also known as Jumpers knee this is tendinitis at the tendon-bone interface of the lower pole
of the patella. This manifests as point tenderness of the lower pole of the patella. The decline
squat test will be positive. This can also be confirmed on USS or MRI. The treatment is
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
initially non-operative with physiotherapy and oral anti-inflammatory medications. Steroid
injection is contraindicated since this may cause tendon rupture. Cases refractory to
conservative management can be managed operatively to try and induce tendon healing by
inflicting surgical trauma at the degenerative site [1]. This can vary from simply scrapping
away at the site of degeneration to stripping of the deeper half of the tendon if it is affected
to drilling the distal pole.
7.2. Bipartite patella
Common in childhood and usually bilateral. The most common site is the superolateral
corner and this is the site most likely to be symptomatic. The most effective surgical
treatment is simply excision of the fragment
7.3. Osteochondritis dissecans
This presents with pain and crepitus in knee extension against a load. Giving-way can be a
result of pain inhibition. Plain XR including 30° skyline view will yield a diagnosis.
Classically the majority of lesions are found in the lateral aspect of the medial femoral
condyle followed by the lateral femoral condyle and patella. Most commonly seen at the
medial patellar facet. Differentiation from chondromalacia patellae may be difficult but
chondromalacia tends to be confined to the overlying cartilage whereas osteochondritis
involves a fragment of bone. There is a high incidence of contralateral limb involvement
15%-30% [61] and so bilateral knee XR is recommended. Subchondral sclerosis can indicate
loosening of the fragment within the crater. CT and MRI will confirm it and show whether
separation has occurred. The presence of homogenous high signal beneath the fragment of
greater than 5mm in diameter may represent an unstable lesion [62].
Arthroscopy will stage the lesion [1]:
1. Intact lesion with no break in articular cartilage
2. Separated lesion with no break in articular cartilage but beneath the intact layer the
bone has separated
3. A trapdoor lesion in which the fragment of osteochondritis dissecans is partially
4. Detached loose body.
Stage 1 can be managed with activity modification and cessation of high impact sports
especially in patients under 14 who would be expected to heal (the presence of an open
physis is encouraging). Separated lesions can be stabilized with biodegradable pins or
osteochondral bone pegs. Stage 3 and 4 should be excised leaving stable vertical edges to the
crater and microfracture to induce healing within the defect with fibrocartilage.
7.4. Synovial impingement
Pathological plicae are difficult to diagnose as they are a normal finding. Superior, medial
and inferior plicae are most common [63]. Identification on arthroscopy does not necessitate
Pain in Perspective
excision unless physical examination is abnormal. Pain is worse with knee flexion and
relived by extension. There may be a thickened palpable cord [64]. Usually the medial plica.
XRs are normal. MRI will identify it but will not necessarily determine if it is pathological.
With stronger magnets for MRI this may change however as wear on the medial femoral
condyle secondary to a thickened medial plica is identified. Conservative management with
activity modification, steroid injections into the plica and physiotherapy is initial treatment
followed by arthroscopic excision if necessary.
Hoffa syndrome presents with swelling in the region of the fat pad. Diagnosed with the
Hoffa maneuver of applying compression either side of the patella tendon while extending
the knee. The test is positive if it elicits pain or apprehension. Diagnosis can be confirmed on
MRI as high signal content consistent with irritation of the fat pad [65]. As before treatment
is with activity modification then debridement if necessary.
7.5. Chondromalacia
Degenerative condition of the articular cartilage not often seen in skeletally immature. XR
are often normal or may show joint space loss if cartilage loss is extensive. Diagnosed on
MRI and Arthroscopy. T2 weighted images with fat saturation or fast spin echo intermediate
weighted MRI demonstrate good contrast at the interfaces between cartilage and
subchondral bone and between cartilage and joint fluid [66]. Usually imaged in the axial
plane identifying potential cartilage defects and internal derangement of the cartilage layer
before gross morphological cartilage loss. In idiopathic cases with limited damage unrelated
to patella subluxation and/or tilt it is acceptable to improve the articular surface
arthroscopically. This reduces the amount of debris in the joint and decreases release of
proteolytic enzymes and decreases synovitis and delaying osteoarthritis onset [67]. The
malacic areas are excised and the subchondral bone is drilled to encourage repair with
fibrocartilage. This however will not withstand the large loads and sheer forces hyaline
cartilage can. Osteochondral grafting in the form of mosaicplasty can be successful for
defects on the femoral condyles but not the undersurface of the patella.
7.6. Patellofemoral osteoarthritis
The standard radiographic features of OA are joint space loss, subchondral sclerosis, cysts
and osteophytes. Such radiographic features are also visible on MRI.
7.7. Patellar maltracking
Treatment is dependant differentiating between patients with normal and abnormal
anatomy. When examining close attention should be paid to any malalignment including
genu valgum, external torsion of the tibia and femoral anteversion which may be associated
subluxation or patellofemoral malalignment [68].
Imaging of the patellofemoral instability patient includes weight bearing AP, 45° PA flexion
and lateral and axial views. These plain XR provide information about osteochondral
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
fractures patellar height, morphology of the trochlear groove, patellar tilt and sulcus angle.
Beyond 45° flexion most patella engage fully with the trochlear groove. As such most
imaging studies of the PF tracking should focus on 30-45° flexion.
CT can be helpful in planning a realignment procedure if necessary. MRI will provide
information regarding the medial retinacular structures (medial patellofemoral ligament
(MPFL) injured in as many as 94-100% of acute patella dislocations [69]. MPFL is
extracapsular and can be missed on arthroscopy which is important as MPFL repair is being
increasingly advocated to prevent recurrent dislocation, chondral damage and ligament
injuries, particularly in cases of acute patella dislocation. Quinn et al [70], described a triad
of injuries on MRI consisting of impaction injury to the lateral femoral condyle,
osteochondral defect (OCD) of the medial patellar facet and injury of the medial patellar
retinaculum. As patellar dislocation can be transient MRI findings provide valuable clues to
the pathology and can be the first indication of the diagnosis.
Skyline views provide only static images from which the patellar dynamics cannot be
understood. It is important to delineate the pattern of maltracking in before considering
management options.
Lateral subluxation in extension is demonstrated clinically by extending the knee against
gravity. As the knee extends from 20° flexion to extension the patella can be observed to kick
laterally and can be accompanied by crepitus and pain as the patella disengages from a
position of stability in the trochlear groove. This is commonly a problem of recurrent
dislocations in childhood. The principal cause is malalignment of the quadriceps. This can
be managed with physiotherapy or distal realignment of the tibial tubercle by 1.5cm +/-
proximal medial advancement of the patellofemoral ligament and lower fibres of vastus
medialis. Lateral release and inner range quadriceps exercises are not appropriate.
Conversely maltracking in flexion is easier to see radiologically on skyline views but more
difficult to examine for clinically beyond symptoms of instability and pain. With pure
subluxation in flexion chondral damage is mild and a simple lateral release will often suffice
[1]. However with combined subluxation and tilt the lateral facet is overloaded and the
chondral damage can be more severe. Subsequently the threshold for performing a distal
realignment is lower.
CT is a very useful imaging modality to study patella tilt and subluxation. Arthroscopy
through anterolateral and superolateral portals will allow assessment of patellar tracking
between 0-90° and also allow the clinician to observe overhang of the lateral facet.
Chronic patellofemoral instability nonoperative treatment focuses on regaining strength in
the quadriceps mechanism and hip abductors. Traditionally for acute dislocation the knee
was immobilized in cylinder cast or cricket pad splint. Others prefer early motion controlled
with lateral buttress bracing. Operative management in the acute setting is indicated for
osteochondral fragment repair or removal. It may also be indicated for repair or
reconstruction of the medial retinacular structures.
Pain in Perspective
7.8. Excessive lateral pressure syndrome
Lateral patellar tilt is dominant with little or no subluxation. Imaging shows cartilage loss,
sclerosis and cystic change of the lateral patella and trochlear. Dynamic studies show lateral
tilt with increasing flexion.
7.9. Patellectomy
Indicated when the articular surface of the patella is so badly damaged over a wide area
that it cannot be salvaged and an otherwise relatively normal knee. The patient should
rehabilitate in a hinged knee brace back to their activities of daily living but will not be
competitive in sports. Quadriceps wasting is inevitable and will not exceed 70% of
normal despite extensive rehabilitation. Complications include rupture, subluxation and
7.10. Complex regional pain syndrome
Complex regional pain syndrome (CRPS) manifests as severe pain, swelling and changes in
the skin. It is often associated with autonomic dysregulation and can lead to functional loss,
impairment and disability. Clinically there must be an initial noxious event that leads to
continuing pain, allodynia or hyperalgesia with evidence of oedema and changes in skin
blood flow in the area of pain. This must all be in the absence of another condition that
could account for such symptoms.
Sweat testing can help in the diagnosis of CRPS. A trial of sympathetic block can also be
useful given the aetiology of the condition. Conventional radiographs can also be useful in
showing the resultant patchy osteoporosis although a three phase technetium bone scan can
detect these changes sooner and will show higher bone density with successful treatment.
Nerve Conduction Studies (NCS) are important tests in CRPS as they are very reliable for
detecting nerve injury (causalgia).
Treatment is multidisciplinary and involves physiotherapy together with drug treatment
such as antidepressants and gamma-aminobutyric acid (GABA) analogues.
7.11. Pain in OA
Pain is the most disabling symptom of OA. Previous work has focused on articular cartilage
as the cause although we cartilage is not innervated with nerve fibres. With the advent of
widespread MRI use we are no able to investigate the whole joint as an organ to identify the
structures that cause pain such that w may develop targeted therapies. In a systematic
review by Yusuf et al [71] there was a moderate level of evidence for a positive association
for BML and effusion/synovitis with pain in OA. There was limited evidence for an
association for knee ligamentous abnormalities and no association with osteophytes and and
subchondral cysts. There was conflicting evidence for cartilage defects, meniscal lesions and
bone attrition.
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
7.12. Physiotherapy management of patellofemoral pain
The aims of interventions described are to improve patellar tracking and reduce abnormal
stress on the PFJ structures.
Patients respond well to a home exercise program initiated by and regularly followed up with
dedicated physiotherapists. General quadriceps exercises are most commonly employed
together with specific vastus medialis obliquus (VMO) targeted training. VMO delay or
reduction in relation to VL is thought to contribute to lateral patellar tracking. Quadriceps
training is the basis of conservative management and studies indicate at least a moderate
reduction in pain when performing such exercises including weight bearing and non-weight
bearing exercises [72]. Witvrouw et al [73] studied the effects of open kinetic chain exercises
(i.e. without weightbearing such as seated knee extension) versus closed chain exercises (such
as leg press) in patients with anterior knee pain. Closed chain exercises produced less pain and
better functional improvement although both exercises were beneficial.
Maximum compressive load is generated 90° flexion in both types of exercises [74] but open
kinetic chain exercises produce higher loads from 45° to full extension. Escamilla et al [75]
showed that closed chain exercises produced greatest quads activity at near full knee flexion
with more activity in the vasti muscle whereas open chain exercises produced greatest
quads activity near full extension with more rectus femoris activation. Further studies [76]
confirmed greater VMO activity with closed chain exercises. Whilst closed chain exercises
seem to confer more advantages not all patients will tolerate them as well as open chain. It is
worth also noting that eccentric strengthening (muscle contraction while lengthening e.g.
walking down stairs) produces the highest muscle strains and so may be recommended for
the later stages of rehabilitation. Flexibility is important in eccentric loading to help absorb
energy [41] and so patients undergoing rehabilitation for anterior knee pain will benefit
from hip, quadriceps, hamstring and gastrocnemius stretching.
While an increased Q angle is thought to predispose the patella to excessive lateral tracking
this has been disputed in recent literature [72]. This may be related to the static nature of a Q
angle measurement that does not reflect real life kinematics. Souza et al et al [77] described
the use of a dynamic Q angle and theorized that femoral adduction and internal rotation
relative to the pelvis impart a valgus knee force and stress lateral PFJ structures. This has
been confirmed on kinematic MRI and has justified the use of targeted hip exercises in
treating patients with PFJ pain. Results from studies indicate that those who participated in
exercise programs targeting hip abductors and external rotators reported at least a moderate
reduction in pain (72) Faulty foot mechanics can also increase the dynamic Q angle [78] and
has led to the use of foot orthosis for the treatment of PFJ pain with moderate success [79].
In combination with quadriceps exercise patellar taping is effective. Taping involves
applying medially directed adhesive tape to glide, tilt and rotate to the patella to increase
patellofemoral contact and reduce pain. Studies have reported a strong reduction in pain
[80]. Whether this effect is due to improved patellar alignment or better proprioceptive
awareness and neuromuscular control is still debated. The evidence for patellar bracing is
less convincing although some studies have shown a moderate improvement [81]. It may be
that bracing shifts contact of the patella with the trochlea to areas of non-irritation.
Pain in Perspective
Whitelaw et al [82] found that 87% of patients with PF pain improved with a combination of
physical therapy and NSAIDS and that 68% of those patients maintained that improvement
at 16 months. Kannus et al [83] followed up patients for 7 years and found that almost three
quarters of patients maintained subjective and functional recovery from 6 months to 7 years
with quadriceps exercises, rest and NSAIDs.
Based on such high success rates patients with PFJ pain should be managed with non-
operative measures till such time that symptomatic improvement has reached an
unacceptable plateau.
8. OA management
8.1. Simple analgesics
Current OA treatment guidelines recommend paracetamol as a first line treatment followed
by a NSAID. NSAIDS are proven to be better at improving pain and function in
osteoarthritis. The combination of paracetamol and ibuprofen is associated with significant
improvements in pain relief, function and quality of life as compared to paracetamol use
alone for both short and long term use [84] but at the expense of an increase in side effects,
primarily GI (PPI) bleeding.
Adjuncts to simple analgesics include weight loss and activity modification and physiotherapy.
Opioid analgesics (such as dermal patches) are also used. Beyond that intra articular HA and
steroid injections are considered the third step in management followed by surgical referral.
8.2. NSAIDs
Trials show that selective Cox-2 inhibitors are less harmful to the lower GI tract than
conventional NSAIDS prescribed together with a proton pump inhibitor gastro-intestinal since
PPIs offer no protection to NSAID induced effects on the small bowel and colonic mucosa [85].
8.3. Hyaluronic acid injection
Hyaluronic acid (HA) injections are widely used in the medical management of knee OA.
There are a variety of different products available on the market with differing molecular
weights, origins, and viscosities. Opinion is divided about the efficacy of HA injections. A
recent meta-analysis [86] confirmed a modest efficacy for knee OA just minimally exceeding
clinical significance. HA was found to be effective at 4 weeks post injection and reach peak
effectiveness at 8 weeks with a residually detectable effect at 24 weeks. When at its peak
effectiveness it appeared to be more effective than acetaminophen and NSAIDS and
comparable to Cox-2 inhibitors.
8.4. Glucosamine
Controversy exists on the efficacy of glucosamine in the symptomatic treatment of knee OA.
Meta-analyses have provided conflicting results. As with HA, conflicting trial results may be
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
due to the use of different formulations. A recent large multicentre double blinded trial
testing glucosamine and chondroitin preparations (GAIT) found that overall, there were no
significant differences between the glucosamine or chondroitin preparations tested and
placebo within the subset of patients with mild knee pain either together or alone. There
was a subset of patients with moderate-to-severe pain, in whom glucosamine combined
with chondroitin sulfate provided statistically significant pain relief compared with placebo.
However, because of the small size of this subgroup these findings should be considered
preliminary and need to be confirmed in further studies.
8.5. Biotherapy
Preclinical studies have shown that nerve growth factor regulates the structure and function
of responsive sensory neurons including small diameter nociceptive afferents [85].
Tanezumab, an antibody against nerve growth factor (NGF) was clinically trialled as the
first biotherapy for knee OA. Early results were impressive for efficacy but trials were halted
by the FDA because of an unexpected increase in joint prosthesis in the tanezumab group
compared to the placebo group. Schnitzer et al 2011 [87] showed that repeated injections of
tanezumab in patients with moderate to severe knee OA provided relief (45-60% reduction
of pain) and better function with a low incidence of side effects (parasthesia).
8.6. Pharmacological treatment reference guide
Simple Mode of action Typical dose Precautions/Side
Paracetamol Not fully understood
– likely COX
500mg-1G QDS Hepatotoxicity in
NSAIDS COX inhibitors Ibuprofen 400mg TDS
roxen 500m
Gastrointestinal and
renal adverse reactions
Opiate alternatives
Codeine Acts on opioid
15-60mg QDS Nausea.
Tramadol Acts on opioid
50-100mg QDS Nausea. Constipation.
. De
Glucosamine/Chondroitin Unknown
1500mg/1200mg Generally safe
aluronic acid Lubricant Intra-articular in
ection Generall
Table 2. Pharmacological treatment reference guide
Pain in Perspective
8.7. Weight loss
Weight loss is difficult to achieve and is perhaps even more difficult to maintain. Despite
this it is frequently recommended for the treatment of OA. In a study by Bliddal et al [88]
reported at 1 year patients allocated to a low fat high carbohydrate and protein diet had
reduced pain in the knee due to OA. This result and others indicate that approximately 30%
of obese patients with knee OA can achieve significant long term weight loss and improve
their pain symptoms. Though studies have shown an improvement in pain levels there is
yet no evidence in difference in function or disability. However as pain is the main problem
of OA there is good justification for advocating weight loss initially.
8.8. Knee arthroplasty
Knee joint replacement is an effective and cost-effective intervention for people with
advanced OA. There are however no clear indications for the use of knee joint replacements
and it can be difficult to know when in the course of OA it is best to operate [89]. This is
evidenced by the great variability in rates of knee joint replacement [90 Furthermore a
minority of patients are made symptomatically worse by surgery. There is also the difficulty
of there being a number of different approaches and prosthesis available and the decision on
whether to perform a total knee replacement or unicompartmental replacement or even high
tibial osteotomy for the young functionally demanding patient with unicompartmental
Ultimately the decision to operate will depend on the best available research evidence in
combination with the experience of the surgeon depending on the individual patient’s needs
and expectations.
8.9. Anaesthesia for knee operations
Most knee operations are now done under a general anaesthetic or a regional anaesthetic or
a combination of the two. For arthroscopic procedures theses are usually performed as
daycase procedures and so a quick general anaesthetic is generally the rule. This is
augmented with a local anaesthetic (such as 10mls 0.5% bupivacaine) injected into the knee
joint and port sites to help with post operative pain relief.
Anaesthesia for knee arthroplasty should provide stable intra-operative conditions and allow
adequate postoperative analgesia to promote early mobilisation and better surgical outcomes.
Regional anaesthetic techniques can have several advantages over general anaesthesia for
knee arthroplasty such as less intra- and post-operative blood loss.
9. Common techniques
9.1. Spinal anaesthesia
Patients will be awake for the procedure. There is a reduced risk of venous
thromboembolism and reduced blood loss compared with general anaesthesia. Spinal
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
anaesthesia provides early postoperative analgesia and can be supplemented by patient
controlled analgesia (PCA).
9.2. Epidural analgesia
Provides very good pain relief which can be extended postoperatively. However it is
dependent on adequate anaesthetic input and training of nursing staff. It has the added
requirement of needing urinary catheterisation which may delay postoperative
mobilisation. Patients need to be aware that they will feel a sensory and motor disturbance
affecting both legs.
9.3. Femoral and sciatic nerve blocks
Do not provide surgical anaesthesia but rather good pain analgesia for to the first 12-24 hrs.
They avoid the need for a urinary catheter in most patients and allow mobility in bed.
9.4. Pain coping skills
Patients with chronic pain often develop maladaptive thought patterns known as pain
catastrophising and abnormal behavior patterns such as guarding or inactivity that
contribute to physical and emotional suffering. In a study by Riddle et al [91] patients
receiving psychologist directed pain coping skills training reported significantly greater
reductions in pain severity and catastrophising as well as improved function. This provides
preliminary evidence that such treatments may be efficient in reducing the number of
patients unhappy with the results of knee arthroplasty.
10. Conclusion
The diagnosis and management of knee pain can be challenging. As with most aspects of
medicine, a thorough history and careful examination will often lead to the correct
diagnosis. Traditionally XR and USS imaging have been the most accessible to the clinician
in confirming the diagnosis. With the increased availability of CT and MR it is now possible
to investigate knee pain in much greater depth within a shorter period of time without
resorting to invasive procedures. With the advances in imaging techniques, particularly in
MRI, soft tissue knee pathologies can be much better delineated and appropriate treatment
planned. This has transformed the diagnosis and management of anterior knee pain.
Nevertheless an experienced physiotherapist is invaluable in treating patients with anterior
knee pain with surgery reserved for when a plateau has been reached which is unacceptable
for the patient. With the advent of more powerful MR scanners and more sophisticated
sequences we can also begin to understand the pathology of knee OA better. Although
undoubtedly BMLs have a role in knee OA their exact relationship to progression of knee
OA and causality is not yet fully understood. No doubt this is an area of future research and
development. The role of analgesics in OA has been proven. As have the surgical options
Pain in Perspective
predominantly in the way of arthroplasty, with good proven results. It is the interim steps in
between that are not yet proven and need further research and development. The role of
biotherapeutic agents whilst temporarily sidelined may become more important if initial
discoveries hold true. We know that pain from OA is likely to be multifactorial and with the
advent of functional MRI we can begin to understand the central processing of pain in
chronic knee OA. This may yield yet more possibilities for the treatment of OA.
Author details
Sherif Hosny, W. McClatchie, Nidhi Sofat and Caroline B. Hing
St George’s Hospital NHS Trust, Blackshaw Road, London, UK
11. References
[1] Jackson, A.M., Anterior Knee Pain. Journal of Bone and Joint Surgery British, 2001. 83B:
p. 937-48.
[2] Cutbill, J.W., et al., Anterior knee pain: a review. Clinical journal of sport medicine, 1997. 7:
p. 40-45.
[3] Kellgren J, Lawrence J. Radiological assessment of osteoarthrosis. Ann rheum Dis
1957;16: 494-502
[4] Ahlbäck S. Osteoarthrosis of the knee: a radiographic investigation. Acta Radiol
Stockholm 1968; (suppl 277):7-72.
[5] Symmons D, Mathers C, Pfleger B. Global burden of osteoarthritis in the year 2000.
Geneva: World Health Organization; 2003.
[6] Dawson J, Linsell L, Zondervan K, Rose P, Randall T, Carr A, Fitzpatrick R.
Epidemiology of hip and knee pain and its impact on overall health status in older
adults. Rheumatology 2004;43:497-504
[7] Haq S, Davatchi F. Osteoarthritis of the knees in the COPCORD world. Int J Rheum Dis
[8] Ingham S, Zhang W, Doherty S, McWilliams D, Muir K, Doherty M. Incident knee pain
in the Nottingham community: a 12-year retrospective cohort study. Osteoarthritis
Cartilage 2011;19:847-852
[9] Nguyen U, Zhang Y, Zhu Y, Niu J, Zhang B, Felson D. Increasing prevalence of knee
pain and symptomatic knee osteoarthritis: Survey and cohort data. Ann Intern Med.
[10] McAlindon T, Snow S, Cooper C, Dieppe P. Radiographic patterns of osteoarthritis of
the knee joint in the community: the importance of the patellofemoral joint. Ann Rheum
Dis 1992; 51:844-849
[11] Jarvholm B, From C,Lewold S, Malchau H, Vingard E. Incidence of surgically treated
osteoarthritis in the hip and knee in male construction workers. Occup Environ Med
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
[12] Miranda H, Viikari-Juntura E, Martikainen R, Riihimaki H. A prospective study on
knee pain and its risk factors. Osteoarthritis Cartilage 2002;10:623–630
[13] Louie G, Ward M. Changes in the rates of joint surgery among patients with
rheumatoid arthritis in California, 1983–2007; Ann Rheum Dis 2010;69:868–871
[14] Fevang B, Lie S, Havelin L, Engesaeter L, Furnes O. Reduction in Orthopedic Surgery
Among Patients With Chronic Inflammatory Joint Disease in Norway, 1994–2004.
Arthritis Rheum 2007;57:529-32.
[15] Morrison J. The mechanics of the knee joint in relation to normal walking. J Biomechanics
[16] Freeman M, Pinskerova V. The movement of the normal tibiofemoral joint. J
Biomechanics 2005;38:197-208
[17] Amis A Farahmand F. Biomechanics masterclass: extensor mechanism of the knee. Curr
Orthop 1996;10:102-109
[18] Feller JA, Amis A, Andrish J, Arendt E, Erasmus P, Powers C. Surgical biomechanics of
the patellofemoral joint. Arthroscopy. 2007;23:542-53.
[19] Witonski, Wagrowska-Danielewicz M. Distribution of substance-P nerve fibres in the
knee joint in patients with anterior knee pain syndrome. Knee Surg Sport Traumatol
Arthrosc. 1999;7:177-83.
[20] Biedert R, Stauffer E, Friederich N. Occurrence of free nerve endings in the soft tissue of
the knee joint: A histologic investigation. Am J Sports Med 1992;20:430-433
[21] Gronblad M, Korkala O, Liesi P, Karaharju E. Innervation of synovial membrane and
meniscus. Acta Orthop Scand 1985;56:484-486
[22] Dye, S.F., The Pathophysiology of Patellofemoral Pain. Clinical Orthopaedics and Related
Research, 2005. NA;(436): p. 100-110.
[23] Bassiouni H. Bone marrow lesions in the knee: the clinical conumndrum. Int J Rheum
Dis 2010;13:196–202
[24] Kraus V, McDaniel G, Worrell T, Feng S, Vail T, Varju G, Coleman R. Association of
bone scintigraphic abnormalities with knee malalignment and pain Ann Rheum
Dis 2009;68:1673-1679
[25] Felson D, McLaughlin S,Goggins J, LaValley M, Gale E, Totterman S, Li W, Hill C, Gale
D. Bone marrow edema and its relation to progression of knee osteoarthritis. Ann Intern
Med. 2003;139:330-336
[26] Hill C. Knee effusions, popliteal cysts, and synovial thickening: association with knee
pain in osteoarthritis. J Rheumatol 2001;28:1330-1337
[27] Valdes A, De Wilde G, Doherty S, Lories R, Vaughn F, Laslett L, Maciewicz r, Soni
A, Hart D, Zhang W, Muir K, Dennison E, Wheeler M, Leaverton P, Cooper C,
Spector T, Cicuttini F, Chapman V, Jones G, Arden N, Doherty M. The Ile585Val
TRPV1 variant is involved in risk of painful knee osteoarthritis. Ann Rheum Dis
[28] Richette P, Bardin T. Gout. Lancet 2010;375:318-328
Pain in Perspective
[29] Lohmander L, Ostenberg A, Englund M, Roos H. High Prevalence of Knee
Osteoarthritis, Pain, and Functional Limitations in Female Soccer Players Twelve Years
After Anterior Cruciate Ligament Injury. Arthritis Rheum 2004;50:3145-3152
[30] Mine T, Kimura M, Sakka A, Kawai S. Innervation of nociceptors in the menisci of
the knee joint: an immunohistochemical study. Arch Orthop Trauma Surg 2000;120:201–
[31] Berthiaume M, Raynauld J, Martel-Pelletier J, Labonte F, Beaudoin G, Bloch D,
Choquette D, Haraoui B, Altman R, Hochberg M, Meyer J, Cline G, Pelletier J. Meniscal
tear and extrusion are strongly associated with progression of symptomatic knee
osteoarthritis as assessed by quantitative magnetic resonance imaging. Ann Rheum Dis
[32] Roos H, Lauren M, Adalberth T, Roos E, Jonsson K, Lohmander L. Knee osteoarthritis
after meniscectomy: Prevalence of radiographic changes after twenty-one years
compared with matched controls. Arthritis Rheum 1998;41:687-693
[33] Englund M, Lohmander L. Risk factors for symptomatic knee osteoarthritis fifteen to
twenty two years after meniscectomy. Arthritis Rheum 2004;50:2811-2819
[34] Wiberg G. Roentgenographic and anatomical studies on the patellofemoral joint: With
special reference to chondromalacia patella Acta Orthop Scand 1941;12:319
[35] Dye S. The pathophysiology of patellofemoral pain: a tissue homeostasis perspective.
Clin Orthop Relat Res 2005;436:100-110
[36] Stanitski C. Anterior knee pain syndromes in the adolescent. J Bone Joint Surg Am
[37] Kodali, P., A. Islam, and J. Andrish, Anterior knee pain in the young athlete, diagnosis and
treatment. Sports Medicine, Arthroscopy Review, 2011. 19: p. 27-33.
[38] Saupe E. Primäre knochenmarkseiterung der kniescheibe. Deutsche Z Chir 1943;258:386-
[39] Nimon G, Murray D, Sandow M, Goodfellow J. Natural history of anterior knee pain:
a 14- to 20-year follow-up of nonoperative management. J Pediatr Orthop. 1998;18:118-
[40] Schiphof D, de Klerk B, Koes B, Bierma-Zeinstra S. Good reliability, questionable
validity of 25 different classification criteria of knee osteoarthritis: a systematic
appraisal. Journal of Clinical Epidemiology 2008;61:1205-1215
[41] Post W. Anterior knee pain: Diagnosis and treatment. J Am Acad Orthop Surg
[42] Cutbill J, Ladly K, Bray R, Thorne, P, Verhoef M. Anterior knee pain: A review. Clin J
Sports Med
[43] Murray TF, Dupont JY Fulkerson JP. Axial and lateral radiographs in evaluating
patellofemoral malalignment. Am J Sports Med 1999;27:580-4
[44] Insall J, Salvati E. Patella position in the normal knee joint. Radiology 1971; 101:101-
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
[45] Egund N. The radiographic axial view of the patellofemoral joint: examination in the
supine or standing position. Eur Radiol 2001;11:130
[46] Muhle C. Brossman J. Heller M. Kinematic CT and MR imaging of the patellofemoral
joint. Eur Radiol 9 508-18 1999
[47] Brossman J, Muhle C, Bull CC, Zieplies J, Melchert UH, Brinkmann G, Schroder C,
Heller M Cine MR imaging before and after realignment surgery for patellar
maltracking comparison with axial radiographs. Skeletal radiology 24: 191-6 1995
[48] Sofat N, Hamann P, Barrick TR, Howe FA. Activation of central pain pathways in
rheumatic diseases: What we have learned from functional neuroimaging studies.
Current rheumatology reviews, 2010,6;3
[49] Baliki M, Katz J, Chialvo DR, Apkarian AV. Single subject pharmacological-MRI (fMRI)
study: modulation of brain activity of psoriatic arthritis pain by cycloxygenase-2
inhibitor. Mol pain 2005;2(1):32
[50] Gwilym S, Keltner JR, warnaby CE, et al. Pschyosocial and functional imaging evidence
supporting the presence of central sensitization in a cohort of osteoarthritis patients.
arthritis rheum 2009; 61(9): 1226-1234
[51] Lee GW, Weeks PM: The role of bone scintigraphy in diagnosing reflex sympathetic
dystrophy. J Hand Surg [Am] 1995;20:458-63.
[52] Van Holsbeeck M, Intracaso JH. Musculoskeletal ultrasonography. Radiol Clin North
Am 1992; 30:907-925
[53] Ptasnik R, Feller J, Bartlett J, Fitt G, Mitchell A, Hennessy O. The value of sonography in
the diagnosis of traumatic rupture of the anterior cruciate ligament of the knee. AJR
1995; 164:1461-1463.
[54] L. Friedman K. Finlay E. Jurriaans Skeletal Radiol (2001) 30:361–377
[55] Bianchi S, Abdelwahab IF, Zwass A et al. Diagnosis of tears of the quadriceps tendon of
the knee: value of sonography. Am J Roentgenol 1994; 162:1137
[56] Jacobson JA, van Holsbeeck MT. Musculoskeletal ultrasonography. Orthop Clin N
Amer 1998; 29:135-167)
[57] Mcalindon TE, Watt I, McCrae F, Goddard P, Dieppe PA. magnetic resonance imaging
in osteoarthritis of the knee: correlation with radiographic and scintigraphic findings.
Ann Rheum disease 1991;50:14-9
[58] Zanetti M, Bruder E, Romero J, Hodler J. Bone marrow edema pattern in osteoarthritic
knees: Correlation between MR imaging and histological findings. Radiology 2000;
[59] Felson DT, Chaisson CE, Hill CL, Totterman SM, Gale ME, Skinner KM, et al. The
association of bone marrow lesions with pain in knee osteoarthritis. Ann Intern med
[60] Tanamas et al. Bone marrow lesions in people with knee osteoarthritis predeict
progression of disease and joint replacement: a longitudinal study. Rheumatology
Pain in Perspective
[61] Hefti F, Beguiristain J, Krauspe R, Möller-Madsen B, Riccio V, Tschauner C, Wetzel R,
Zeller R.J Osteochondritis dissecans: a multicenter study of the European Pediatric
Orthopedic Society. Pediatr Orthop B. 1999 Oct;8(4):231-45.
[62] De Smet AA, Ilahi OA, Graf BK. Untreated osteochondritis dissecans of the femoral
condyles: prediction of patient outcome using radiographic and MR findings. Skeletal
Radiol. 1997 Aug;26(8):463-7.
[63] Dupont JY. Synovial plicae of the knee. Controversies and review. Clin Sports Med.
1997 Jan;16(1):87-122.
[64] Medial plica syndrome. Sznajderman T, Smorgick Y, Lindner D, Beer Y, Agar G. Isr
Med Assoc J. 2009 Jan;11(1):54-7.
[65] Jacobson JA, Lenchik L, Ruhoy MK, Schweitzer ME, Resnick D. MR imaging of the
infrapatellar fat pad of Hoffa. Radiographics. 1997 May-Jun;17(3):675-91.
[66] Elias DA, White LM. Imaging of patellofemoral disorders. Clinical radiology 2004;59:
[67] Muckle DS, Minns RJ. Biological response to woven carbon fibre pads in the knee. A
clinical and experimental study. J Bone Joint Surg Br. 1990 Jan;72(1):60-2.
[68] Kodali P, Islam A, Andrish J. Anterior Knee Pain in the Young Athlete Diagnosis and
Treatment. Sports Med Arthrosc Rev 2011;19:27–33
[69] Nomura E. Classification of lesions of the medial patello-femoral ligament in patellar
dislocation. Int Orthop. 1999;23(5):260-3.
[70] Quinn SF, Brown TR, Demlow TA. MR imaging of patellar retinacular ligament injuries.
J Magn Reson Imaging. 1993 Nov-Dec;3(6):843-7.
[71] Yusuf E, Kortekaas MC, Watt I, Huizinga TW, Kloppenburg M. Do knee abnormalities
visualised on MRI explain knee pain in knee osteoarthritis? A systematic review. Ann
Rheum Dis. 2011 Jan;70(1):60-7.
[72] Bolgla, L.A. and M.C. Boling, Systematic review of the literature: an update for the
conservative management of patellofemoral pain syndrome: a systematic review of the literature
from 2000 to 2010. The International Journal of Sports Physical Therapy, 2011. 6(2): p.
[73] Witvrouw E, Lysens R, Bellemans J, Peers K, Vanderstraeten G. Open versus closed
kinetic chain exercises for patellofemoral pain. A prospective, randomized study. Am J
Sports Med. 2000 Sep-Oct;28(5):687-94.)
[74] Wilk KE, Escamilla RF, Fleisig GS, Barrentine SW, Andrews JR, Boyd ML. A
comparison of tibiofemoral joint forces and electromyographic activity during open and
closed kinetic chain exercises. Am J Sports Med. 1996 Jul-Aug;24(4):518-27.
[75] Escamilla RF, Fleisig GS, Zheng N, Barrentine SW, Wilk KE, Andrews JR. Biomechanics
of the knee during closed kinetic chain and open kinetic chain exercises. Med Sci Sports
Exerc. 1998 Apr;30(4):556-69.
[76] Tang SF, Chen CK, Hsu R, Chou SW, Hong WH, Lew HL. Vastus medialis obliqus and
vastus lateralis activity in open and closed kinetic chain exercises in patients with
Knee Pain in Adults & Adolescents, Diagnosis and Treatment
patellofemoral pain syndrome: an electromyographic study. Arch Phys Med Rehabil.
2001 Oct;82(10):1441-5.
[77] Souza RB, Draper CE, Fredericson M, Powers CM. Femur rotation and patellofemoral
joint kinematics: a weight-bearing magnetic resonance imaging analysis. J Orthop
Sports Phys Ther. 2010 May;40(5):277-85.
[78] Tiberio D. Evaluation of functional ankle dorsiflexion using subtalar neutral position. A
clinical report. JOSPT Phys Ther. 1987 Jun;67(6):955-7
[79] Collins N, Crossley KM, Beller E, Darnell R, McPoil T, Vicenzino B. Foot orthoses and
physiotherapy in the treatment of patellofemoral pain syndrome: randomized clinical
trial.Br J Sports med 2009;43(3):169-171
[80] Crossley KM, Bennell KL, Green S, Cowan SM, McConnel J. Physical therapy for
patellofemoral pain. A randomized double blinded, placebo-controlled trial. Am J
sports med 2002;30(6):857-865
[81] Lun VM, Wiley JP, Meeuwisse WH, Yanagawa TL. Effectiveness of patellar bracing for
treatment of patellofemoral pain syndrome. Clin J sport med 2005;35(4):235-240
[82] Whitelaw GP Jr, Rullo DJ, Markowitz HD, Marandola MS, DeWaele MJ. A conservative
approach to anterior knee pain. Clin Orthop Relat Res. 1989 Sep;(246):234-7
[83] Kannus P, Natri A, Paakkala T, Järvinen M. An outcome study of chronic
patellofemoral pain syndrome. Seven-year follow-up of patients in a randomized,
controlled trial. J Bone Joint Surg Am. 1999 Mar;81(3):355-63.
[84] Doherty M et al. A randomised controlled trial of ibuprofen, paracetamol or a
combination tablet of ibuprofen/paracetamol in community-derived people with knee
pain. Ann Rheum Dis 2011;70:1534-1541.
[85] Berenbaum F. Osteoarthritis year 2010 in review: Pharmacological therapies.
Osteorthritis and cartilage 19 (2011) 361-365.
[86] Bannuru RR, Natov NS, Dasi UR, Schmid CH, McAlindon TE. Therapeutic trajectory
following intra-articular hyaluronic acid injection in knee osteoarthritis--meta-analysis.
Osteoarthritis Cartilage. 2011 Jun;19(6):611-9.
[87] Schnitzer TJ, Lane NE, Birbara C, Smith MD, Simpson SL, Brown MT. Long-term open-
label study of tanezumab for moderate to severe osteoarthritic knee pain. Osteoarthritis
Cartilage. 2011 Jun;19(6):639-46.
[88] Bliddal et al. Weight loss as treatment for knee osteoarthritis symptoms in obese
patients: 1-year results from a randomised controlled trial. Ann Rheum Dis
[89] Dieppe P, Lim K, Lohmander S. Who should have knee joint replacement surgery for
osteoarthritis?. Int J Rheum Dis. 2011 May;14(2):175-80.
[90] T. Dixona, M.E. Shawb, P.A. Dieppe. Analysis of regional variation in hip and knee
joint replacement rates in England using Hospital Episodes Statistics. Public Health.
2006;120(1) 83–90
Pain in Perspective
[91] Riddle DL, Keefe FJ, Nay WT, McKee D, Attarian DE, Jensen MP. Pain coping skills
training for patients with elevated pain catastrophising who are scheduled for knee
arthroplasty: a quasi-experimental study. Arch phys rehabil. 2011 Jun;92(6):859-65.)
... Despite its prevalence, AKP nature and causes remain inadequately understood and can be bothersome for patients and clinicians as it causes chronic disability, limited sports and activity, and a negative impact on the quality of life [3,4]. Many authors linked AKP to the patellofemoral pathology, especially the patellofemoral instability, while others clearly reported that structural anomalies did not provide a complete explanation of the pain [5]. Moreover, structural anomalies were found to be minor among AKP patients, and there was no obvious correlation between patellofemoral malalignment and long-term results of AKP treatment [6]. ...
... Despite its prevalence, AKP nature and causes remain inadequately understood and can be bothersome for patients and clinicians as it causes chronic disability, limited sports and activity, and a negative impact on the quality of life [3,4]. Many authors linked AKP to the patellofemoral pathology, especially the patellofemoral instability, while others clearly reported that structural anomalies did not provide a complete explanation of the pain [5]. Moreover, structural anomalies were found to be minor among AKP patients, and there was no obvious correlation between patellofemoral malalignment and long-term results of AKP treatment [6]. ...
Background: Anterior knee pain (AKP) is a problematic complaint, considered to be the most frequent cause of orthopedic consultancy for knee problems. This study aimed to highlight diagnostic accuracy of ultrasonography as a fast imaging technique in assessment of patients with AKP. Methods and results: A prospective study was conducted on 143 patients with clinically confirmed AKP. All patients underwent ultrasonography and MRI examinations of the knee. The diagnostic accuracy of ultrasonography compared to MRI for evaluating different findings of possible causes of AKP were analyzed using receiver operating characteristic (ROC) curve and judged by area under curve (AUC). A total of 155 knees were included in the study; 26 knees showed no abnormalities, 19 knees showed positive MRI only, and 110 knees showed positive ultrasonography and MRI. Ultrasonography and MRI reported 11 different findings of possible causes of AKP or related to it. Joint effusion was the most common finding (38%) followed by trochlear cartilage defect (20.6%) and superficial infrapatellar subcutaneous edema (20%). The overall accuracy of ultrasonography was 85.3% sensitivity and 100% specificity. The ultrasonography provided the highest sensitivity (100%) in detecting bipartite patella, followed by 91.5% for joint effusion, and 87.5% for quadriceps tendinopathy. The ROC curve analysis of overall accuracy of ultrasonography showed an AUC of 0.93. The overall Kappa agreement between ultrasonography and MRI was good (k = 0.66). Conclusion: Ultrasonography can be used to make a swift screening and assessment of painful anterior knee and as an alternative to MRI when it is unavailable or contraindicated.
Full-text available
Background Anterior knee pain (AKP) is a problematic complaint, considered to be the most frequent cause of orthopedic consultancy for knee problems. This study aimed to highlight diagnostic accuracy of ultrasonography as a fast imaging technique in assessment of patients with AKP. Methods and results A prospective study was conducted on 143 patients with clinically confirmed AKP. All patients underwent ultrasonography and MRI examinations of the knee. The diagnostic accuracy of ultrasonography compared to MRI for evaluating different findings of possible causes of AKP were analyzed using receiver operating characteristic (ROC) curve and judged by area under curve (AUC). A total of 155 knees were included in the study; 26 knees showed no abnormalities, 19 knees showed positive MRI only, and 110 knees showed positive ultrasonography and MRI. Ultrasonography and MRI reported 11 different findings of possible causes of AKP or related to it. Joint effusion was the most common finding (38%) followed by trochlear cartilage defect (20.6%) and superficial infrapatellar subcutaneous edema (20%). The overall accuracy of ultrasonography was 85.3% sensitivity and 100% specificity. The ultrasonography provided the highest sensitivity (100%) in detecting bipartite patella, followed by 91.5% for joint effusion, and 87.5% for quadriceps tendinopathy. The ROC curve analysis of overall accuracy of ultrasonography showed an AUC of 0.93. The overall Kappa agreement between ultrasonography and MRI was good ( k = 0.66). Conclusion Ultrasonography can be used to make a swift screening and assessment of painful anterior knee and as an alternative to MRI when it is unavailable or contraindicated.
Full-text available
Pain is a major symptom in rheumatic diseases. Understanding the nature of patients pain symptoms in a rheumatology setting is integral to their assessment and optimising care. In recent years we have increasingly come to appreciate that not only is pain dependent on the underlying pathological process, but is also influenced by a number of additional factors that include genetics, the environment of the individual, previous pain experience and psychological status. Although local inflammation in the joint leads to the release of pro-inflammatory mediators including prostaglandins and cytokines that activate nociceptive signals in the joint, recent work has suggested that central activation of the brain is also important in mediating chronic pain in a number of rheumatic conditions including rheumatoid arthritis, fibromyalgia, osteoarthritis and back pain. A number of imaging modalities have been utilized in recent years to gain a deeper understanding of the pathways involved in the perception of pain in the rheumatic diseases. Functional Magnetic Resonance Imaging (fMRI), has been used to assess how the brain responds to and also mediates pain in the presence of arthritic disease. Positron emission tomography (PET) and Single photon emission computed tomography (SPECT) can produce blood flow images of the brain, or with the appropriate choice of radiopharmaceutical can also be used to image metabolic activity or specific neuroreceptors. Magnetoencephalography (MEG) can map cortical brain activity with high temporal resolution. These techniques have shown altered regional cerebral blood flow in areas of the brain in rheumatoid arthritis and fibromyalgia and have been used to determine pathways implicated in the perception of pain in specific conditions including complex regional pain syndrome and fibromyalgia. The information gained from functional imaging studies has improved our understanding of pain perception in rheumatic diseases and so may aid a more effective treatment for pain as will be discussed further in this review.
Background: Patellofemoral pain syndrome is a highly prevalent musculoskeletal overuse condition that has a significant impact on participation in daily and physical activities. A recent systematic review highlighted the lack of high quality evidence from randomised controlled trials for the conservative management of patellofemoral pain syndrome. Although foot orthoses are a commonly used intervention for patellofemoral pain syndrome, only two pilot studies with short term follow up have been conducted into their clinical efficacy. Methods/design: A randomised single-blinded clinical trial will be conducted to investigate the clinical efficacy and cost effectiveness of foot orthoses in the management of patellofemoral pain syndrome. One hundred and seventy-six participants aged 18–40 with anterior or retropatellar knee pain of non-traumatic origin and at least six weeks duration will be recruited from the greater Brisbane area in Queensland, Australia through print, radio and television advertising. Suitable participants will be randomly allocated to receive either foot orthoses, flat insoles, physiotherapy or a combined intervention of foot orthoses and physiotherapy, and will attend six visits with a physiotherapist over a 6 week period. Outcome will be measured at 6, 12 and 52 weeks using primary outcome measures of usual and worst pain visual analogue scale, patient perceived treatment effect, perceived global effect, the Functional Index Questionnaire, and the Anterior Knee Pain Scale. Secondary outcome measures will include the Lower Extremity Functional Scale, McGill Pain Questionnaire, 36-Item Short-Form Health Survey, Hospital Anxiety and Depression Scale, Patient-Specific Functional Scale, Physical Activity Level in the Previous Week, pressure pain threshold and physical measures of step and squat tests. Cost-effectiveness analysis will be based on treatment effectiveness against resource usage recorded in treatment logs and self-reported diaries. Discussion: The randomised clinical trial will utilise high-quality methodologies in accordance with CONSORT guidelines, in order to contribute to the limited knowledge base regarding the clinical efficacy of foot orthoses in the management of patellofemoral pain syndrome, and provide practitioners with high-quality evidence upon which to base clinical decisions.
Patients with patellofemoral pain represent a significant challenge to the orthopaedic community. The origin of patellofemoral pain can be directly traced to supraphysiologic mechanical loading and chemical irritation of nerve endings, denoting loss of tissue homeostasis. The persistent biologic cascade of cytokine production can lower the load-acceptance capacity of soft tissues and activate painful osseous remodeling. Activities of daily living can become supraphysiologic loads to sensitized patellofemoral tissues, resulting in chronic reactivation of tissue inflammation. The principles of treatment in most patients with patellofemoral pain consist of protection of sensitive tissues from excessive loading, appropriate antiinflammatory therapy, and nonirritat-ing rehabilitation. (C) Lippincott-Raven Publishers.
Es wird eine weitere Beobachtung einer der sehr seltenen primÄren Knochenmarkseiterungen der Kniescheibe mitgeteilt. Die mit den bisherigen FÄllen übereinstimmenden und von diesen abweichenden Besonderheiten derselben werden beschrieben.