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Adipose Tissue as Pain Generator in the Lower Back and Lower Extremity: Application in Musculoskeletal Medicine

  • HMH JFK-Johnson Rehabilitation Institute
Lee et al. HCA Healthcare Journal of Medicine (2020) 1:5
Clinical Review
Adipose Tissue as Pain Generator in the Lower
Back and Lower Extremity: Application in
Musculoskeletal Medicine
Se Won Lee, MD ,1 Craig Van Dien, MD ,2 Sun Jae Won, MD, PhD3
Adipose tissue (AT) has diverse and important functions in body insulation, mechanical
protection, energy metabolism and the endocrine system. Despite its relative abundance in
the human body, the clinical significance of AT in musculoskeletal (MSK) medicine, partic-
ularly its role in painful MSK conditions, is under-recognized. Pain associated with AT can
be divided into intrinsic (AT as a primary pain generator), extrinsic (AT as a secondary pain
generator) or mixed origin. Understanding AT as an MSK pain generator, both by mechanism
and its specific role in pain generation by body region, enhances the clinical decision-making
process and guides therapeutic strategies in patients with AT-related MSK disorders. This
article reviews the existing literature of AT in the context of pain generation in the lower
back and lower extremity to increase clinician awareness and stimulate further investigation
into AT in MSK medicine.
adipose tissue; fat pad; musculoskeletal pain; connective tissue; lipodystrophy; lipoma; obe-
sity; lipedema; pain generator
Author aliations are listed
at the end of this article.
Correspondence to:
Se Won Lee, MD
Department of Physical
Medicine and Rehabilitation
MoutainView Medical
2880 N Tenaya Way, 2nd Fl,
Las Vegas, NV 89128
© 2020 HCA Physician Services, Inc. d/b/a
Emerald Medical Education
HCA Healthcare
Journal of Medicine
Mounting evidence supports the various func-
tions of adipose tissue (AT), most notably its
link to obesity and metabolic dysfunction.1-3
Aside from the impact of obesity on the mus-
culoskeletal (MSK) system, the role of AT in
painful MSK conditions is less established.
Historically, AT masses/lipomas were consid-
ered common pain generators. However, the
high prevalance of asymptomatic lipomas,4,5
inconsistent responses to local injections and
increasing awareness of other neighboring pain
generators disputed their reputation in painful
MSK conditions. AT has recently re-entered
the focus of MSK clinicians, most notably for
its use in regenerative medicine.6 Moreover,
localization and evaluation with high resolution
imaging technologies has improved under-
standing of AT in other contexts, particularly
pain generation. Therefore, our objective is to
review the available literature on AT-related
painful MSK disorders in the lower back and
lower extremity, focusing on its pathogenic role
as a pain generator as well as practical diagno-
sis and management.
Distribution, Physiologic Changes
and Mechanical Properties of
Adipose Tissue
AT is largely located in subcutaneous regions,
followed by visceral regions. Ectopic areas
of deposition include bone marrow and the
retro-orbital, intramuscular, intermuscular
and periarticular regions.7 With aging, there is
global redistribution of AT from subcutaneous
to truncal/visceral regions.8 Local redistribution
also occurs, as seen in AT on the plantar aspect
of the heel and metatarsophalangeal joints.9 In
addition, aging AT cells undergo cellular senes-
cence, a process that promotes AT dysfunction
through dysregulation of extracellular remod-
eling, inflammation and pathologic angiogene-
HCA Healthcare Journal of Medicine
AT is a highly expandable connective tissue
comprised of adipocytes (lipid-filled cells)
enclosed within collagen-based structures
(basement membrane and interlobular septa)
and smaller numbers of fibroblasts.11 It protects
the underlying MSK structures, contributes to
mechanical stability and resists shear strain.12
Nonetheless, the mechanical integrity of AT
varies between individuals and over an individ-
ual’s lifespan. For example, the stiness and
thickness of heel AT was found to be higher in
overweight and obese individuals as compared
to normal-weight individuals.12 This discovery is
partly explained by increased fibrosis, a process
that limits the ability of adipocytes to expand.13
Increased stiness can also reflect a degenera-
tive process, as repetitive microtrauma reduces
water content and elastic fibrous tissues.13-15
Furthermore, septal hypertrophy and frag-
mented elastic fibers in heel AT occurs with ag-
ing.12 These changes can negatively impact the
mechanical properties of AT and consequently
its functions in shock absorption and resistance
to compressive and sheer forces of gait.12
Adipose Tissue as an Intrinsic and
Extrinsic Pain Generator
Pain-related to AT falls into two categories: 1)
Intrinsic: pain originating directly from/within
AT and 2) Extrinsic: pain related to the interac-
tion of AT with surrounding structures. Mixed
processes are not uncommon.
Intrinsic Pain Generation
Dye et al. described pain perception of dier-
ent intraarticular structures in a conscious in-
dividual by arthroscopic probing and found the
infrapatellar fat pad to be both highly localized
and sensitive compared to neighboring struc-
tures.16 In an alternative study, similar noxious
responses were induced by injecting hyperton-
ic saline (5%) into the infrapatellar fat pad.17
Such findings underscore the rich nociceptive
innervation of fat pads by substance-P and
calcitonin gene-related peptide nerve fibers
and lend credibility to pain originating directly
from AT.18 Moreover, AT is metabolically active
and produces proinflammatory adipokines
such as tumor necrosis factor-alpha, leptin,
vaspin, chemerin and interleukin-6.3,19,20 As an
example, pain syndromes due to inflamed fat
pads are well described in patients with HIV.
These pain syndromes include retrocalcaneal
pain from isolated inflammation of Kager’s fat
pad and nonspecific anterior knee pain related
to inflammation of the infrapatellar fat pad.21
AT torsion resulting in inflammation and/or
ischemic necrosis is amongst other proposed
mechanisms of AT-based pain.22
Extrinsic Pain Generation
Painful MSK conditions can be related to the
interaction of AT with surrounding structures,
i.e., extrinsic pain generator. Lipomas, for ex-
ample, are AT masses that can arise from any
location where fat is normally present. Local
pain in lipomas can result from irritation of a
fascial layer or other neighboring structures,
such as bursa and nerve.23 If nerve irritation oc-
curs, distant pain (either radiating or referred)
can be experienced.24 The pain characteristics
and presentation of painful fat pads/symp-
tomatic lipoma will vary based on the body
region and surrounding structures. (Table 1) As
another example, increased adiposity can cause
tendinopathy due to direct mechanical loading
and biochemical alterations caused by systemic
dysmetabolic factors.25 Rich neovasculariza-
tion and sensory innervation of AT surrounding
tendons may also play a role in chronic tendon
pain.26 In addition, there is evidence that AT can
contribute to the development of osteoarthri-
tis via adipokines, such as leptin, visfatin and
resistin.19 Other processes, such as the loss of
the AT structural integrity, can contribute to
pain generation. This loss is observed in plantar
fat pad atrophy.27
Mechanisms and Biomechanics of
Musculoskeletal Pain Generation:
Regional Approach
Lower Back and Buttock
Episacroiliac subcutaneous lipomas, or “back
mice,” are subfascial fat herniations that may
be encountered in patients with nonspecific
low back pain.4 These lipomas are oen bilat-
eral and located near the sacroiliac “dimple,
posterior iliac crest and lumbar paraspinal area.
(Figure 1) There appears to be a female predi-
lection. Subfascial herniation to the myofascial
layer makes symptomatic lipoma dicult to
distinguish from myofascial pain syndrome. A
discrete, large and painful palpable nodule fa-
vors lipoma herniation rather than a myofascial
trigger point.23
Lee et al. (2020) 1:5.
Table 1. Classification of painful adipose tissue/fat pad disorders aecting lower back and lower
Location Common pathologies Characteristics and suggested mechanisms of pain
Systemic Adipose Tissue Disorders
(congenital and
Chronic pain with neuropathic pain most common, fol-
lowed by arthralgia, muscle pain Common chronic periph-
eral neuropathy
Pain and tenderness in the bilateral lower extremities,
skin hypersensitivity, neural tissue compression within the
septa surrounding fat lobules
Partial lipodystrophy
Hoa’s fat pad with anterior (infrapatellar) knee pain and
Kager’s fat pad with posterior heel pain, anterior to the
Achilles tendon in patients with HIV infection
Adiposis dolorosa
(Dercum’s disease)
Painful subcutaneous adipose tissues involving extremi-
ties, torso and even face
Adipose Tissue Pain Generation by Body Region
Lower back
and buttock
Subcutaneous painful
fat pad
Episacroiliac subcutaneous lipomas, “back mice”, irritating
myofascia, fascial herniation and torsion of fat pad, com-
monly in the episacral region, oen bilateral
Can cause neuropathic pain by irritation of cluneal nerves
Spinal lipoma
Lipomyelomeningocele (fatty mass in conus medullaris),
lipoma of the terminal ilum causing tethered cord/root
Spinal epidural lipomatosis (primary and secondary) with
lumbosacral radiculopathy
Hip and
Painful fat pad
Femoral fat pad entrapment with femoroacetabular
impingement, anterior inferior iliac spine fat pad causing
adhesion of joint capsule and gluteal muscle
Lipoma Deep large intramuscular lipoma with thigh pain
Knee Painful fat pad
Hoa’s infrapatellar fat pad impingement, suprapatellar,
prefemoral fat pad impingement syndrome (hyperexten-
sion of knee) with anterior knee pain
Lipoma arborescens Involving suprapatellar recess
Ankel and
Lipoma Retrocalcaneal bursitis
Painful fat pad Insertional Achilles tendinopathy
Fat pad atrophy and
Nociceptive pain on the heel (plantar aspect) and forefoot
Piezogenic pedal
Subcutaneous fat herniation in the heel, especially in
weight bearing
Lipomas of the spinal cord are rare tumors of-
ten associated with occult spinal dysraphism.24
Spinal lipomas are more commonly located in
the conus medullaris and called lipomyelome-
ningocele. Lipomyelomeningocele is character-
ized by a subcutaneous fibrofatty mass, lamina
defect, compressive myelopathy and tethered
cord syndrome.28 It can present with progres-
sive neurological deficit in the lower extremities
with the loss of bladder function.24 Lipoma of
the terminal filum is another common cause of
tethered cord syndrome with lower back pain as
the first presenting symptom.29 Spinal epidural
lipomatosis is extremely uncommon and can be
found incidentally or present symptomatically as
radiculopathy, neurogenic claudication and
HCA Healthcare Journal of Medicine
myelopathy.30 It has been associated with exog-
enous steroid use (epidural or chronic systemic
steroids), endogenous hypercortisolism (Cush-
ing’s syndrome), hypothyroidism, hyperprolac-
tinemia and protease inhibitors in patients with
HIV.31 Spinal epidural lipomatosis is most oen
localized to the thoracic spine followed by lum-
bosacral spine.30,32
Hip and Thigh
Femoral fat pads were recently recognized as
a source of pain in femoroacetabular impinge-
ment syndrome, with fat pad entrapment
occurring between the femoral head-neck
junction and labrum. In patients with cam-type
femoroacetabular impingement, Jayasekera
et al. observed similar clinical outcomes with
arthroscopic resection of the femoral fat pads
in the anterior head-neck junction with or
without creating a spherical femoral head.33 In
addition, anterior inferior iliac spine fat pads
have been implicated in anterior groin pain as a
consequence of inflammation, fibrosis, scar and
adhesion (between the joint capsule, rectus
femoris and gluteus muscles).34
Most lipomas in the thigh are asymptomatic
but can be painful when situated deep (under
the enclosing fascia, in the intramuscular and
intermuscular layers) or if they are large (usual-
ly due to the expansion of so tissue or com-
pression of the peripheral nerve).35,36
Infrapatellar or Hoa’s fat pad impingement
syndrome is a well-known cause of anterior
knee pain that occurs at either the infrapatellar
or peri-patellar region during knee hyperexten-
sion. Hoa’s fat pad can be impinged by any
combination of neighboring structures, includ-
ing the patella and patellar tendon anteriorly,
femoral condyle posteriorly and proximal tibia
caudally.37 (Figure 2) A minor injury to Hoa’s
fat pad, including hyperextension with or with-
out twisting and a direct trauma, can cause
swelling, inflammation, fibrosis and scarring
that contributes to the altered biomechanics
and increased pain perception.37 Anterior knee
pain can also result from anterior suprapatellar
fat pad impingement. This triangular-shaped
fat pad is located on the superior edge of the
patella (underneath the quadriceps tendon,
anterior/superficial to the suprapatellar re-
cess).38,39 Impingement occurs during maximal
knee flexion. Lastly, the prefemoral fat pad, lo-
cated proximal to the femoral trochlea, can be
impinged between the patella and anterolateral
surface of the distal femur during flexion and
extension of the knee.40,41
Lipoma arborescens is a benign, “tree-like”
AT lesion characterized by the replacement
of subsynovial connective tissue with AT and
synovial villous proliferation. This replacement
can result in intermittent painful swelling of
the knee joint, typically involving the suprapa-
Figure 1. Ultrasonographic figure of multiple fat pads on the lumbosacral region in a patient with
chronic low back pain.
Lee et al. (2020) 1:5.
tellar bursa.42 Other reported locations include
the hip and ankle joints. It is more common
in males between the 5th and 6th decades of
life and is associated with osteoarthritis and
inflammatory arthropathy.43
Ankle and Foot
Kager’s fat pad is bordered by the Achilles
tendon, retrocalcaneal bursa and flexor hallucis
longus tendon in the posterior ankle.44 (Figure
2) It reduces tendon kinking and minimizes
pressure on the bursa.45 Patients with Kager’s
fat pad impingement can present with a painful
bulging mass at the retrocalcaneal space of the
posterior ankle. Symptoms are exacerbated by
ankle plantarflexion with a knee hyperextension
(recurvatum) momentum in a closed kinetic
chain movement. Pathologies of the neighbor-
ing structures and lipodystrophy (LD) of the
fat pad can also contribute to impingement.21
A lipoma beneath the flexor retinaculum of the
tarsal tunnel can cause tarsal tunnel syndrome.
It manifests with pain behind the medial malle-
olus that radiates to the plantar aspect of the
Fat pad atrophy and migration occurs in the
sole of an aging foot at the superficial to me-
dial calcaneal tuberosity48 and under the meta-
tarsal heads. It is oen associated with plantar
heel pain, metatarsalgia and metatarsal sublux-
ation. In addition to normal age-related chang-
es, fat pad atrophy can occur as a consequence
of steroid injections.49,50
Piezogenic pedal papules are herniations of the
subcutaneous fat into the plantar fascia reti-
naculum. They are common incidental findings
in weight-bearing areas of the foot, particularly
the plantar heel fat pad.51 The papules may only
be visible in full weight-bearing. Although a
Figure 2. Ultrasonographic figures of fat pads (yellow colored line) in the anterior knee (right
upper corner) and the posterior ankle (le lower corner). Red arrows indicate proposed impinge-
ment mechanisms of these fat pads.
HCA Healthcare Journal of Medicine
majority of lesions are asymptomatic, papules
may be discretely tender on palpation. Irritation
of local nerves and blood vessels by repetitive
trauma can contribute to pain.52
Systemic Adipose Disorders
Although painful MSK conditions related to fo-
cal AT are the main focus of this paper, system-
ic adipose disorders, in particular lipedema and
lipodystrophy (LD), may likewise cause lower
back and lower extremity pain and, therefore,
will be briefly reviewed.
LD is a heterogeneous group of disorders
characterized by abnormal distribution of AT,
including AT loss or hypertrophy.53,54 LD can be
classified into primary (idiopathic or familial)
versus secondary depending on the underly-
ing etiology (HIV, panniculitis, autoimmune,
medication, trauma), or general versus partial
depending on the extent of involvement.55-57
More than 70% of patients with LD suer
from chronic pain, most commonly neuro-
pathic pain, followed by arthralgia and muscle
pain amongst others. Peripheral sensory-mo-
tor neuropathy is found in more than 60% of
patients with LD and diabetes.58 Underlying
mechanisms for peripheral neuropathy in LD
are not entirely clear but likely include a com-
bination of metabolic dysfunction and a failure
of the shock-absorbing function of peripheral
nerves. Specifically, loss of epineural fat com-
ponents is thought to contribute to chronic
trauma, inflammation/pressure palsies and
denervation.58-61 Muscle pain is common in
congenital LD, but readily apparent myopathy
is not common in LD other than a late compli-
cation of juvenile dermatomyositis.58
Lipedema, a type of LD, is characterized by
abnormal deposition of subcutaneous AT,
frequently involving the lower extremities
symmetrically.62-64 There is a demographic
predilection for females of a younger age and
commonly a family history.62 A typical patient
complaint is pressure,-mediated leg pain and
tenderness. These symptoms may be a conse-
quence of neural compression within the septa
surrounding fat lobules. Other potential mech-
anisms include hypersensitivity, mechanical
friction and skin irritation.62 As the hypertrophy
extends from hips to ankles, lipedema may
be misdiagnosed as lymphedema.62 In com-
parison, lymphedema is typically painless and
involves the foot, whereas lipedema commonly
spares the foot with a step-o (cu sign) at
the ankle.65 The absence of pain and edema can
dierentiate lipohypertrophy from lipedema.64
Adiposis dolorosa, also known as Dercum’s
disease, shares similar clinical features with
lipedema, such as painful subcutaneous AT and
a predominance in females between the ages
of 35–50 years.66,67 Fat involvement of the torso
in early stages of the disease, greater pain
severity and comorbidities such as fibromyalgia
and metabolic disease distinguishes adiposis
dolorosa from lipedema.68,69
Evaluation with Imaging
A majority of MSK disorders related to AT are
clinically diagnosed. Imaging modalities are
helpful to confirm the clinical diagnosis, evalu-
ate dierential diagnoses and aid in the iden-
tification of indiscrete masses in patients with
larger body habitus. With the increasing avail-
ability of ultrasonography (US) in outpatient
clinics, lipomas can be easily visualized in-oce
(Figure 1). Typical findings include a partially
or well-encapsulated mobile mass with similar
echogenicity to the neighboring fat (hypoecho-
ic or isoechoic depending on the heterogenicity
of AT and water components) and absence of
acoustic shadowing.70,71 Dierential diagnoses
for subcutaneous AT masses include epidermal
cyst, ganglion cyst and malignant neoplasm.
Epidermal cysts are isoechogenic, which is
similar to subcutaneous lipomas. However,
post-acoustic enhancement and lateral shad-
owing are dierentiating characteristics. Gan-
glion cysts typically demonstrate anechogenic-
ity within the cyst, with protrusion towards a
neighboring joint.72 US imaging of so tissue
malignant neoplasms, most commonly pleo-
morphic sarcoma and liposarcoma, can mimic
a lipoma. However, they typically demonstrate
larger size (≥ 5 cm), are intramuscular, have an
infiltrative border, grow rapidly and violate tis-
sue planes.71 Dierential diagnoses for deep-ly-
ing lipomas in US evaluation are extensive and
vary depending on mass location. These dier-
ential diagnoses may include congenital cysts,
ganglion cyst, heterotopic ossification, heman-
giomas, angiolipoma, hematoma, lymph nodes,
normal muscle/muscle herniation and malig-
nant tumors, amongst others.36,73 Sonoelastog-
raphy provides information on intrinsic tissue
Lee et al. (2020) 1:5.
properties. This information aides in the delin-
eation of malignant tumors, which are generally
stier than benign masses.74,75 Any suspicion for
malignant neoplasm requires further imaging
studies and the definite diagnosis with histo-
pathologic and molecular examination.
MRI is useful when US assessment is di-
cult. Examples include deeper, intraarticular
or intracortical lesions.76 On both T1 and T2
weighted images, lipomas demonstrate high
signal intensity, while fat-suppression sequenc-
es show decreased signal intensity.36 Increased
lipoma signal intensity on fat-suppression
sequences may indicate edema/fluid, necrosis
or mass heterogeneity (as seen in an atypical
tumor or liposarcoma).77 An MRI can also eval-
uate neighboring structures such as ganglion
cyst, plica, synovium, ligament, meniscus, bony/
tendon edema or any neoplastic lesions.37 A CT
can similarly be utilized to evaluate lipomas,
which would appear as a hypodense mass with
attenuation similar to fat tissue. A CT can be
particularly useful to delineate subtle ossifica-
tion/calcification and associated cortical bony
lesions.78 An x-ray is limited in the evaluation
of so tissue lesions (lipoma) in general but
serves utility in the identification of intraosse-
ous lipomas mimicking other diseases such as
fibrous dysplasia, aneurysmal bone cysts, sim-
ple cysts, bone infarcts and chondral tumors.79
Clinicians should be aware of the limitation
of imaging modalities, including inconsistent
relationships between the imaging findings and
the local pain.80
The first step for the successful management
of symptomatic AT is to recognize AT as a
pain generator and investigate the underlying
mechanisms for the pain. This review primarily
focuses on the management of focal AT-related
painful MSK disorders; LD will be briefly cov-
Local, non-pharmacological interventions that
may improve AT-related disorders in the lower
back and lower extremities include orthotics,
taping and modification of daily activity. For
fat pad atrophy and migration in the foot, heel
cups (rubber or felt pad) and low dye taping
can be tried for heel pain and a metatarsal pad
for metatarsalgia.81 Repeat steroid injections
through the plantar fat (during plantar fascia
and intermetatarsal bursa/neuroma injec-
tions) should be avoided to prevent atrophy.
Ethanol-based nerve fiber ablation has been
previously attempted to mitigate pain associ-
ated with AT. However, caution is required as
AT scarring and denaturing can occur. Biome-
chanical evaluation and avoiding faulty training
(with repetitive trauma) should be considered
a means to alleviate pain and prevent progres-
sion and recurrence. Symptomatic Hoa’s fat
pad impingement with pes cavus may respond
to heel li placement by mitigating knee ex-
tension moments known to aggravate symp-
toms.82 Placing a pillow under the knee avoids
full knee extension, relieving pain associated
with sleeping in the supine position.
Weight loss should also be emphasized to
decrease metabolic dysfunction and the bio-
mechanical disadvantages associated with
increased weight. Weight loss has favorable
impacts on pain and biomechanics of the lower
extremity, including decreased foot plantar
loading pressure, increased ankle plantarflex-
ion, knee joint motion (maximal knee flexion),
compressive force and peak moments around
the hip and knee.83-85 However, evidence re-
flecting the impact of weight loss in AT-related
painful MSK disorders is scarce and unclear.
Okifuji and Hare suggested obesity may not
impact pain response in the absence of in-
flammation or nerve injury, though obesity can
potentiate inflammatory response.86 Dodet et
al.87 and Zahorska-Markiewicz et al.88 reported
higher pain thresholds among the obese pop-
ulation compared to the nonobese population.
Although the exact mechanisms were not clear,
ghrelin and galanin were suggested for mod-
ulation of the obesity-induced change in pain
threshold.89,90 Regardless of the direct impact
of obesity and weight loss on AT-related pain,
aerobic endurance exercise is important to
decrease complications related to chronic MSK
pain and to improve metabolic dysfunction.91
Surgical options can be considered in patients
who fail conservative treatment and have dis-
abling pain. Potential interventions include fat
pad resection in impingement syndrome. These
interventions include intraarticular or extraar-
ticular fat pad resection in anterior groin pain,
Hoa’s fat pad resection in anterior knee pain
and Kager’s fat pad resection in retrocalcaneal
HCA Healthcare Journal of Medicine
heel pain.34,9 2,9 3 Scarring of the surgical site and
the impact of regional stability can be challeng-
ing postoperatively. Alternatively, US guided
scraping of vascularized fat pads can relieve
pain from neighboring chronic tendinopathy.26
A few studies highlight the non-cosmetic im-
plantation of fat for fat pad atrophy, such as
fat graing for metatarsalgia and chronic heel
pain.27,94,9 5
As it pertains to LD, management should focus
on symptomatic manifestations and metabolic
syndrome. Recombinant human leptin (me-
treleptin) is considered for generalized LD, with
low serum leptin levels to improve metabolic
syndrome and weight loss.96,97 In secondary LD,
recognizing and managing the underlying etiol-
ogy is useful for successful treatment.98
AT should be recognized as one of the pain
generators in painful musculoskeletal disorders.
Therapeutic strategies for adipose tissue-re-
lated pain disorders could be better guided by
understanding the mechanism by which AT-re-
lated pain is occurring.
Conflicts of Interest
The authors declare they have no conflicts of
Dr. Lee is an employee of Sunrise Health GME
Consortium, a hospital aliated with the
journal’s publisher.
This research was supported (in whole or in
part) by HCA Healthcare and/or an
HCA Healthcare aliated entity. The views
expressed in this publication represent those of
the author(s) and do not necessarily represent
the ocial views of HCA Healthcare or any of
its aliated entities.
Author Aliation
1. Department of Physical Medicine and Reha-
bilitation, Sunrise Health GME Consortium,
Las Vegas, NV
2. Department of Physical Medicine and
Rehabilitation, JFK Johnson Rehabilitation
Institute, Edison, NJ
3. Department of Rehabilitation Medicine,
Yeouido St. Mary’s Hospital, College of
Medicine, The Catholic University of Korea,
Seoul, South Korea
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... Masruroh and Setyadhani showed a direct correlation between obesity level and the incidence of knee joint pain in the elderly in a cross-sectional approach on 50 individuals [24]. A proposed mechanism associated with obesity and musculoskeletal disorders arises from the production of pro-inflammatory cytokines from high excess adipose tissue in obese individuals [25]. Leptin is a pro-inflammatory adipokine that is highly elevated in obese individuals in which leads to deforming cartilage and be involved in the pathogenesis of arthralgia [26,27]. ...
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Background: This study was evaluated the association between obesity phenotypes and risk of lower torso musculoskeletal disorders including low back pain (LBP), low back stiffness (LBS), arthralgia, and joint stiffness in Ravansar non-communicable diseases (RaNCD) cohort study. Methods: In this cross-sectional study, 6940 adults were examined for the presence of lower torso musculoskeletal disorders by a physician. Obesity phenotypes including metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) were defined based on the International Diabetes Federation, as well as, body mass index > 30 kg/m2. Metabolically unhealthy non-obesity (MUNO) phenotype was considered as unhealthy metabolic without obesity. Results: The prevalence of LBP, LBS, arthralgia, and joint stiffness in MHO, MUO, and MUNO were significantly higher than in healthy participants compared to obesity phenotypes. Logistic regression showed that MHO phenotype was significantly increased with risk of LBP (OR: 1.19, CI 95%: 1.01-1.41), LBS (OR: 1.44, CI 95%: 1.12-1.86), arthralgia (OR: 1.54, CI 95%: 1.33-1.78), and joint stiffness (OR: 1.84, CI 95%: 1.35-2.52). Moreover, MUO phenotype was positively associated with risk of LBS (OR: 1.46, CI 95%: 1.09-1.94) and arthralgia (OR: 1.66, CI 95%: 1.41-1.96). In addition, MUNO phenotype was associated with a higher risk of arthralgia (OR: 1.21, CI 95%: 1.06-1.37). Conclusion: All three phenotypes, MHO, MUO and MUNO were significantly increased the risk of arthralgia. However, MHO phenotype was significantly associated with a higher risk of all examined lower torso musculoskeletal disorders in the current study.
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Dercum's disease (adiposis dolorosa) is a rare disease of unknown etiology characterized by painful subcutaneous adipose tissue deposits with various localization over the body. The deposits occur histologically as lipomas and are associated with overweight or obesity and a variety of psychiatric disturbances (anxiety, depression, sleep disturbances). Classification of Dercum's disease is related to size and location of adipose nodules (generalized diffuse, generalized nodular, localized nodular and juxta-articular forms). Diagnosis in based on clinical presentation and exclusion of a number of other disorders associated with lipomas. There is no generally accepted management of the patients. Liposuction or lidocaine application has been reported successful in some cases. Other therapeutic methods have been reported but their effectiveness is based on anecdotal descriptions only, and were not confirmed in clinical trials.
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Case We report a rare case of prefemoral fat pad impingement syndrome that was caused by a hyperplasia of the normal suprapatellar fat pad. Pain and catching were observed in the proximal-lateral patellofemoral joint, and MRI imaging confirmed a hyperplasic mass in the same area. Although conservative treatment showed no signs of improvement, symptoms improved after an arthroscopic excision of the mass. Conclusion Prefemoral fat pad impingement syndrome is related to patellar motion and should be considered as one of the underlying causes of anterior knee pain (AKP). Surgeons should recognize that a small hyperplasia composed of normal adipose tissue can cause AKP.
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Purpose of Review The purpose of this review is to summarize the therapeutic approach for lipodystrophy syndromes with conventional treatment options and metreleptin therapy in detail and to point out the current investigational treatments in development. Recent Findings The observation of leptin deficiency in patients with lipodystrophy and the potential of leptin replacement to rescue metabolic abnormalities in animal models of lipodystrophy were followed by the first clinical study of leptin therapy in patients with severe lipodystrophy. This and several other long-term studies demonstrated important benefits of recombinant human leptin (metreleptin) to treat metabolic abnormalities of lipodystrophy. These studies ultimately led to the recent FDA approval of metreleptin for the treatment of generalized lipodystrophy and EMA approval for both generalized and partial lipodystrophy. Additional research efforts in progress focus on novel treatment options, predominantly for patients with partial lipodystrophy. Summary Current treatment of generalized lipodystrophy includes metreleptin replacement as an adjunct to diet and standard treatment approach for metabolic consequences of lipodystrophy. Beyond metreleptin, a number of different compounds and treatment modalities are being studied for the treatment of partial lipodystrophy.
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Obesity increases the risks of developing cardiovascular and metabolic diseases and degrades quality of life, ultimately increasing the risk of death. However, not all forms of obesity are equally dangerous: some individuals, despite higher percentages of body fat, are at less risk for certain chronic obesity-related complications. Many open questions remain about why this occurs. Data suggest that the physical location of fat and the overall health of fat dramatically influence disease risk; for example, higher concentrations of visceral relative to subcutaneous adipose tissue are associated with greater metabolic risks. As such, understanding the determinants of the location and health of adipose tissue can provide insight about the pathological consequences of obesity and can begin to outline targets for novel therapeutic approaches to combat the obesity epidemic. Although age and sex hormones clearly play roles in fat distribution and location, much remains unknown about gene regulation at the level of adipose tissue or how genetic variants regulate fat distribution. In this review, we discuss what is known about the determinants of body fat distribution, and we highlight the important roles of sex hormones, aging, and genetic variation in the determination of body fat distribution and its contribution to obesity-related comorbidities.
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Purpose: The purpose of this study was to investigate the feasibility of shear wave ultrasound elastography for differentiating superficial benign soft tissue masses through a comparison of their shear moduli. Methods: We retrospectively analyzed 48 masses from 46 patients from February 2014 to May 2016. Surgical excision, fine-needle aspiration, and clinical findings were used for the differential diagnosis. The ultrasonographic examinations were conducted by a single musculoskeletal radiologist, and the ultrasonographic findings were reviewed by two other radiologists who were blinded to the final diagnosis. Conventional ultrasonographic features and the median shear modulus were evaluated. We compared the median shear moduli of epidermoid cysts, ganglion cysts, and lipomatous tumors using the Kruskal-Wallis test. Additionally, the Mann-Whitney U test was used to compare two distinct groups. Results: Significant differences were found in the median shear moduli of epidermoid cysts, ganglion cysts, and lipomatous tumors (23.7, 5.8, and 9.2 kPa, respectively, P=0.019). Epidermoid cysts showed a greater median shear modulus than ganglion cysts (P=0.014) and lipomatous tumors (P=0.049). Conclusion: Shear wave elastography may contribute to the differential diagnosis of superficial benign soft tissue masses through a direct quantitative analysis.
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Purpose For patients who have anterior hip pain evaluated by Patrick’s test and tenderness at Scarpa’s triangle, we perform periarticular debridement based on the hypothesis that extra-articular pathologies are responsible for the hip pain. The purpose of this study was to categorize the endoscopic extra-articular findings and to evaluate the clinical significance of periarticular pathologies in anterior hip pain. Methods Arthroscopic findings of 77 patients who underwent periarthritic debridement were evaluated. As extra-articular pathologies, injuries of the direct head and reflective head of the rectus femoris muscle were evaluated. A thin layer of fat tissue normally exists on the anterior inferior iliac spine (AIIS), the attachment site of the direct head of the rectus femoris muscle. The macroscopic appearance of the fat pad on the AIIS was categorized as normal, blood vessel-rich adipose tissue or adipose tissue with fibrosis or scar formation and histologically confirmed. Adhesion of gluteal muscles to the joint capsule was also evaluated. Results Of the 77 patients, 75 had rupture of the direct head of the rectus femoris. In contrast, rupture of the reflective head was extremely rare. Seven patients had a normal fat pad on the AIIS, 11 had blood vessel-rich adipose tissue and 55 had adipose tissue with fibrosis. Fat tissue was completely replaced by fibrous scar tissue in another 4 patients. In 64 patients, adhesion between the anterior joint capsule and gluteus muscles was marked. Groin pain disappeared soon after the operation even when labral tears were not repaired and all patients returned to daily life and sports activities within 2 weeks after operation. Conclusion Rectus femoris tendinosis, fibrosis of the AIIS fat pad, and adhesion of gluteal and rectus femoris muscles are common extra-articular pathologies in patients with anterior hip pain. Management of only these lesions induces rapid relief of anterior hip pain even in the absence of labral tear repair. My observations suggest that it is desirable to be aware of the presence of periarticular pathologies as a cause of groin pain.
Background: Lipedema and Dercum's disease (DD) are incompletely characterized adipose tissue diseases, and objective measures of disease profiles are needed to aid in differential diagnosis. We hypothesized that fluid properties, quantified as tissue water bioimpedance in the upper and lower extremities, differ regionally between these conditions. Methods and Results: Women (cumulative n = 156) with lipedema (n = 110), DD (n = 25), or without an adipose disease matched for age and body mass index to early stage lipedema patients (i.e., controls n = 21) were enrolled. Bioimpedance spectroscopy (BIS) was applied to measure impedance values in the arms and legs, indicative of extracellular water levels. Impedance values were recorded for each limb, as well as the leg-to-arm impedance ratio. Regression models were applied to evaluate hypothesized relationships between impedance and clinical indicators of disease (significance criteria: two-sided p < 0.05). Higher extracellular water was indicated (i) in the legs of patients with higher compared with lower stages of lipedema (p = 0.03), (ii) in the leg-to-arm impedance ratio in patients with lipedema compared with patients with DD (p ≤ 0.001), and (iii) in the leg-to-arm impedance ratio in patients with stage 1 lipedema compared with controls (p ≤ 0.01). Conclusion: BIS is a noninvasive portable modality to assess tissue water, and this device is available in both specialized and nonspecialized centers. These findings support that regional bioimpedance measures may help to distinguish lipedema from DD, as well as to identify early stages of lipedema.
Soft tissue masses and fluid collections are frequently encountered in sonographic practice, either as principal indication for diagnostic examination or as an incidental finding during an examination performed for other indications. Sonography is a good first-line imaging modality for evaluation of superficial masses and fluid collections, but requires meticulous attention to technique to avoid diagnostic pitfalls. Although many superficial masses are diagnosed with ultrasound, there are several potential diagnostic challenges, including differentiating hematomas from sarcomas. This article provides an image-rich review of the sonographic features of common soft tissue masses, with emphasis on practical tips to accurately recognize important pathology.
Background: By age 60, 30% of Americans suffer from fat pad atrophy of the foot. Forefoot fat pad atrophy results from long-term aggressive activity, genetics dictating foot type, multiple forefoot steroid injections, surgery and foot trauma. Methods: We present data from a two-year, prospective, randomized cross-over study performed to assess pain and disability indexes, fat pad thickness, forces and pressures of stance and gait. Group 1 underwent fat grafting with two years of follow-up, while Group 2 underwent conservative management for 1 year, then received fat grafting with 1 year of follow-up. Results: 18 subjects (14 female, 4 male) comprised Group 1. 13 subjects (9 female, 4 male) comprised Group 2. Group 1 reported the worst pain at baseline, Group 2 experienced the worst pain at 6, 12-month Standard of Care (SOC) visits; pain for both groups immediately improved following fat grafting and lasted through study follow up (p<0.05). Group 1 demonstrated functional improvements at 12, 18, 24 months post-operatively (p<0.05); while Group 2 demonstrated highest function at 12-months post-op (p<0.05). Pedal fat pad thickness of subjects in Group 1 increased following post-op and returned to baseline thickness at 2 months post-op; subjects in Group 2, experienced return to baseline thickness at 6 months post-op (p<0.01). Forces and pressures of stance and gait increased over the 2 years of follow-up for Group 1 (p<0.05). Conclusions: Pedal fat grafting provides long-lasting improvements in pain, function, and prevents against worsening from conservative management.
Background context: Spinal epidural lipomatosis (SEL) is a condition in which excess lumbar epidural fat (EF) deposition often leads to compression of the cauda equina or nerve root. Although SEL is often observed in obese adults, no systematic research investigating the potential association between SEL and metabolic syndrome has been conducted. Purpose: To elucidate potential association between SEL and metabolic syndrome. Study design: An observational study used data of a medical checkup. Patient sample: We retrospectively reviewed data from consecutive subjects undergoing medical checkups. A total of 324 subjects (174 men and 150 women) were enrolled in this study. Outcome measures: The correlation of EF accumulation with demographic data and metabolic related factors were evaluated. Methods: The degree of EF accumulation was evaluated based on the axial views of lumbar magnetic resonance imaging. Visceral and subcutaneous fat areas were measured at the navel level using abdominal computed tomography. Metabolic syndrome was diagnosed according to the criteria of the Japanese Society of Internal Medicine. The correlation of SEL with metabolic syndrome and metabolic-related conditions was statistically evaluated. Results: The degree of EF accumulation demonstrated a significant correlation to body mass index, abdominal circumference, and visceral fat area. However, age, body fat percentage, and subcutaneous fat area showed no correlation with the degree of EF accumulation. Logistic regression analysis revealed that metabolic syndrome [odds ratio (OR) = 3.8, 95% confidence interval (CI) = 1.5-9.6] was significantly associated with SEL. Among the diagnostic criteria for metabolic syndrome, visceral fat area ≥ 100 cm2 (OR = 4.8, 95% CI = 1.5-15.3) and hypertension (OR = 3.5, 95% CI = 1.1-11.8) were observed to be independently associated with SEL. Conclusion: This is the first study to demonstrate that metabolic syndrome is associated with SEL in a relatively large, unbiased population. Our data suggest that metabolic-related conditions are potentially related to EF deposition and that SEL could be a previously unrecognized manifestation of metabolic syndrome.