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Malalignment and Degenerative Arthropathy
Abstract
The axial relationship of the joints of the lower extremity reflects both alignment and orientation. Static considerations are useful for preoperative planning and deformity correction, but dynamic considerations including compensatory gait may be more relevant clinically. Laboratory animal models have been developed that simulate the deleterious effect of malalignment on articular cartilage. Malalignment disturbs the normal transmission of force across the knee, and altered stress distribution related to deformity has been demonstrated in cadaver models using pressure-sensitive film. No prospective data are available to document the natural history of malalignment, but several retrospective studies suggest the clinical course is one of gradual progression resulting in degenerative arthropathy. The long-term follow-up of fractures is less definitive, and difficult to interpret considering the bias inherent in patient selection. Although direct clinical evidence of a cause-and-effect relationship between malalignment and arthrosis has not been possible, substantial evidence from the orthopedic literature supports this hypothesis.
... The lower extremity is in the frontal plane aligned through a mechanical axis which is in a neutral positioned extremity running from the hip joint, medially or through the middle of the knee joint to the ankle joint (Tetsworth and Paley, 1994). A malalignment is present when the axis is shifted medial or lateral of the knee joint, creating a moment arm and causing a disturbance in the load bearing of the joints (Sharma et al., 2010). ...
... The KAM and the load on the medial knee compartment can be reduced by changing the gait pattern, external foot rotation or external support (Tetsworth and Paley, 1994). Conservative approaches can include knee bracing. ...
Knee malalignment is shown to be an independent risk factor for osteoarthritis pro-gression. The knee adduction moment is directly correlated with varus malformation and can be decreased with changes in gait pattern, external foot rotation and external support. The aim of this literature review was to determine the effects of different therapeutic approaches in treating varus malalignment of the knee joint. The literature search was conducted in the PubMed and EBSCO databases. We used a combination of English keywords. Studies were screened regarding the inclusion and exclusion crite-ria. We included five studies investigating the effects of therapeutic approaches in participants with or without osteoarthritis onset. Statistically significant decrease in knee adduction moment was reported in one study, which was implementing modified gait pattern with real time feedback. Other outcome measures were also indicative of potential efficacy in different therapeutic approaches. There is a bigger potential for treating varus malalignment before osteoarthritis (OA) onset. The results indicate that weight-bearing exercise and gait modification in combination with a corrective train-ing protocol provide a potential useful approach to reduce varus malalignment. Keywords: Varus malalignment, knee joint, knee adduction moment, therapeutic approaches
... It is believed that these biomechanical changes associated with femoral malrotation can lead to functional impairments and contribute to an increased incidence of hip and knee osteoarthritis. [22,25,26] Some injury patterns appear to be more prone to indirect methods of malreduction compared to others. Long-term outcome studies examining the development of joint disease associated with poorly rotated limbs should be conducted. ...
... [54] Regardless of the choice of fixation, perioperative complications associated with supracondylar femur fractures include delayed or nonunion requiring revision surgery, deep infection, proximal implant failure, and malunion. [26,70,71] Knee stiffness is prevalent in approximately 48% of cases, and other complications such as reduction loss (7%), fracture of locking screws (8%), and anterior knee pain (22%) have been reported. [16,19] Reduction loss, malunion, rotational malposition, and nonunion can lead to revision surgeries ranging from 19% to 23%. ...
Treatment of osteoporotic distal femur fractures is often complicated by a high rate of nonunion and varus collapse. For such fractures, lateral plating with lateral incision and double plating with anterior paramedial incision have shown promising results in the recent literature. The hypothesis of this study was that bilateral plating of comminuted distal femur fractures in osteoporotic patients would result in higher union rates and lower revision rates compared to an isolated lateral locking plate. The study included 56 patients (23 males, 33 females) with supracondylar femur fracture. According to the OA/OTA classification, 9 were type A3, 8 were A2, 13 were C1, 16 were C2, and 10 were C3. The mean follow-up period was 12 months, with 29 patients treated using lateral mini-incision, lateral locking plate, and 27 patients treated with anterior paramedial incision, dual plating. The clinical and radiological results were evaluated. The mean duration of radiological union in the studied population was 15 ± 2.1 months (range, 11–21 months) in the single plate group (Group A), and 13.5 ± 2.6 months (range, 9–19 months) in the double plate group (Group B). Mean ROM was 112.3° and flexion contracture 4° in Group A, and ROM 108.3° and flexion contracture 6.7° in Group B. ( P = .15). The average Western Ontario and McMaster Universities Arthritis Index (WOMAC) score was 85.6 points in Group A and 83.5 points in Group B ( P = .2278). The postoperative anteversion measurement in the operated extremity ranged from −15 to 19 in Group A, and from 5 to 18 in Group B. When the anteversion degrees were compared between the injured and uninjured extremities in the postoperative period, a significant difference was observed within Group A ( P = .0018), but no significant difference was observed in Group B ( P = .2492). Dual plate fixation using the anterior paramedial approach is an effective operative method for osteoporotic distal femur fractures. This has many advantages such as precise exposure, easy manipulation, anatomic reduction, and stable fixation. However, for surgical indications and medial bone defects > 1 cm, grafting should be performed.
... Undeniably, the success of both surgical and conservative management of knee deformities depends mainly on the restoration of normal alignment and normal joint orientation. 18 If knee replacement, for example, leaves the extremity in malalignment, loosening and instability occur at a greater rate than if the limb is well aligned. 19 Indeed, malalignment of greater than 5° in either varus or valgus direction has been shown to be associated with more functional decline compared to knees with less malalignment. ...
Studies have shown that knee alignment parameters differ among races. However, to our knowledge, radiographic frontal plane knee alignment has not been studied in normal northern Nigerian adults. The objective of this study was therefore to determine the frontal plane knee alignment in normal northern Nigerian adults. This study recruited a total of 59 consented subjects (44 males, 15 females). The entire subjects are without any history of lower extremity deformity. Anteroposterior radiographs of both knees with the patella positioned straight ahead were obtained from each participant while standing in a relaxed bipedal stance and placing equal weight on each limb. Alignment was assessed by measuring the tibiofemoral angle (TFA), distal femoral angle (DFA) and proximal tibial angle (PTA). The angles were measured with the aid of a universal plastic goniometre and a plastic ruler. Descriptive statistics of the alignment parameters, independent and paired t-test were computed. In the male population, the mean (standard deviation) obtained were 179.06 (3.87) o for the TFA, 85.94 (3.03 o for the DFA and 89.27 (3.26) o for the PTA. In the female population, the values were 179.53 (3.38) o for the TFA, 86.40 (2.97) o for the DFA and 89.27 (2.15) o for the PTA. No significant mean difference was observed between genders in all the parameters. The TFA does not show any significant difference between the right and left angle regardless of gender. However, significant mean differences were observed in the DFA and PTA of males and combined population. No significant difference was observed in the DFA and PTA of females. Accordingly, northern Nigerian adults may have varus knee alignment compared to other races. Thus, this pre-existing varus alignment should be taken into consideration during clinical examination , preoperative planning and postoperative evaluations of knee deformities in this population.
... From a biomechanical perspective, injuries to cartilage and bone weaken their ability to withstand abnormal loads, leading to more severe structural damage (34,35). Fractures and joint misalignments, such as varus and valgus deformities, result in incongruent joint lines and mechanical axis deviation, altering joint load distribution (36)(37)(38). ...
Osteoarthritis is the most prevalent age-related degenerative joint disease and a leading cause of pain and disability in aged people. Its etiology is multifaceted, involving factors such as biomechanics, pro-inflammatory mediators, genetics, and metabolism. Beyond its evident impact on joint functionality and the erosion of patients’ quality of life, OA exhibits symbiotic relationships with various systemic diseases, giving rise to various complications. This review reveals OA’s extensive impact, encompassing osteoporosis, sarcopenia, cardiovascular diseases, diabetes mellitus, neurological disorders, mental health, and even cancer. Shared inflammatory processes, genetic factors, and lifestyle elements link OA to these systemic conditions. Consequently, recognizing these connections and addressing them offers opportunities to enhance patient care and reduce the burden of associated diseases, emphasizing the need for a holistic approach to managing OA and its complications.
Background
Deformity correction has been long performed using internal fixation. Since the introduction of external fixation in orthopedic practice, it has gained popularity in correcting severe deformities, and many orthopedic surgeons have resorted to external fixation to correct severe deformities. The authors asked if internal fixation can be safely used to correct significant deformities with marked mechanical axis deviation thus abolishing the notion that external fixation is the only available option to correct severe deformities.
Patients and methods
A single-center, prospective study was conducted at an academic center from October 2014 to December 2016. A total of 37 patients with lower limb deformities were included in the study. Overall, 13 patients were corrected using locked plates and 24 patients were corrected using intramedullary nails. The average follow-up was 13.5 months (10–18 months).
Results
The desired correction was achieved in all patients. Union was quicker with plates, but this could be attributed to the younger age of patients in that group.
Discussion
Many methods of fixation have been used to correct angular deformities around the knee. With patients’ satisfaction gaining utmost importance recently, surgeons have been revising their approach in managing various orthopedic conditions, and limb deformity is no exception. During the surgeons’ pursuit to achieve their patients’ maximum satisfaction without compromising the accuracy of correction or rigidity of fixation, two new techniques have emerged, namely, fixator-assisted plating and fixator-assisted nailing techniques, which represent a breakthrough in deformity correction, because they combine the advantages of internal and external fixation. The use of internal fixation usually yields higher patients’ satisfaction.
Conclusion
Internal fixation is a safe and effective treatment option for correcting significant deformities of the lower limb.
Osteoarthritis (OA) is a common chronic disease largely driven by mechanical factors, causing significant health and economic burdens worldwide. Early detection is challenging, making animal models a key tool for studying its onset and mechanically-relevant pathogenesis. This review evaluate current use of preclinical in vivo models and progressive measurement techniques for analysing biomechanical factors in the specific context of the clinical OA phenotypes. It categorizes preclinical in vivo models into naturally occurring, genetically modified, chemically-induced, surgically-induced, and non-invasive types, linking each to clinical phenotypes like chronic pain, inflammation, and mechanical overload. Specifically, we discriminate between mechanical and biological factors, give a new explanation of the mechanical overload OA phenotype and propose that it should be further subcategorized into two subtypes, post-traumatic and chronic overloading OA. This review then summarises the representative models and tools in biomechanical studies of OA. We highlight and identify how to develop a mechanical model without inflammatory sequelae and how to induce OA without significant experimental trauma and so enable the detection of changes indicative of early-stage OA in the absence of such sequelae. We propose that the most popular post-traumatic OA biomechanical models are not representative of all types of mechanical overloading OA and, in particular, identify a deficiency of current rodent models to represent the chronic overloading OA phenotype without requiring intraarticular surgery. We therefore pinpoint well standardized and reproducible chronic overloading models that are being developed to enable the study of early OA changes in non-trauma related, slowly-progressive OA. In particular, non-invasive models (repetitive small compression loading model and exercise model) and an extra-articular surgical model (osteotomy) are attractive ways to present the chronic natural course of primary OA. Use of these models and quantitative mechanical behaviour tools such as gait analysis and non-invasive imaging techniques show great promise in understanding the mechanical aspects of the onset and progression of OA in the context of chronic knee joint overloading. Further development of these models and the advanced characterisation tools will enable better replication of the human chronic overloading OA phenotype and thus facilitate mechanically-driven clinical questions to be answered.
Over the years, with a better understanding of knee anatomy and biomechanics, superior implant designs, advanced surgical techniques, and the availability of precision tools such as robotics and navigation, a more personalized approach to total knee arthroplasty (TKA) has emerged.
In the presence of extra-articular deformities, performing personalized TKA can be more challenging and specific considerations are required, since one has to deal with an acquired pathological anatomy.
Performing personalized TKA surgery in patients with extra-articular deformities, the surgeon can: (1) resurface the joint, omitting the extra-articular deformity; (2) partially compensate the extra-articular deformity with intra-articular correction (hybrid technique), or (3) correct the extra-articular deformity combined with a joint resurfacing TKA (single stage or two-stage procedure).
Omitting the acquired lower limb malalignment by resurfacing the knee has the advantages of respecting the joint surface anatomy and preserving soft tissue laxities. On the other hand, it maintains pathological joint load and lower limb kinematics with potentially detrimental outcomes.
The hybrid technique can be performed in most cases. It circumvents complications associated with osteotomies and brings lower limb axes closer to native alignment. On the other hand, it creates some intra-articular imbalances, which may require soft tissue releases and/or constrained implants.
Correcting the extra-articular deformity (through an osteotomy) in conjunction with joint resurfacing TKA represents the only true kinematic alignment technique, as it aims to reproduce native knee laxity and overall lower limb axis.
Purpose
Congenital femoral deficiency is characterized by limb length discrepancy and genu valgum. Lengthening of the femur along its anatomic axis increases valgus alignment by medial knee translation. Pairing limb lengthening with simultaneous medial distal femoral hemiepiphysiodesis can simultaneously correct two limb deformities.
Methods
All skeletally immature patients with congenital femoral deficiency who underwent antegrade femoral lengthening and concomitant guided growth over a 4-year period were reviewed. Length and alignment data were quantified during lengthening, consolidation, and for 1 year after guided growth implants were removed or the patient reached skeletal maturity. Digital simulation was performed for all lengthenings to assess the mechanical alignment that would have been achieved had lengthening been performed without medial distal femoral hemiepiphysiodesis.
Results
Nine patients (five males, four females, mean age = 12.3 ± 1.9 years) underwent 10 antegrade intramedullary femoral lengthenings with simultaneous medial distal femoral hemiepiphysiodesis. All had improvement in valgus alignment (average improvement in mechanical axis deviation was 18 ± 11 mm, average change in limb alignment was 6 ± 5°). In simulated lengthenings without guided growth, all limbs would have experienced increased lateral mechanical axis deviation of 5 ± 3 mm. The hemiepiphysiodesis implant and lengthening device were explanted simultaneously in 7 of 10 lengthenings.
Conclusion
Simultaneous medial distal femoral hemiepiphysiodesis with antegrade femoral lengthening for ongenital femoral deficiency can minimize the number of surgical episodes for the skeletally immature patient. The lengthening device and guided growth construct can be removed simultaneously in a majority of cases, saving children one or two additional surgical treatments.
Linear and angular measurements were made on thirty-two cadaveric femora with respect to the mechanical (functional) axes of the bone. The long axis was defined as a line from the center of the femoral head to the anterolateral attachment of the posterior cruciate ligament. The transverse axis was defined as a line through the posterior cruciate ligament parallel to the line connecting each epicondyle. The condylar width, the length of each interepicondylar line, correlated well with depth, but the projections of the condyles from the transverse plane revealed significant variations from specimen to specimen. Considerable variation also was found between femora in terms of angular dimensions (that is, the angle of anteversion and the neck-shaft angle proximally, and the valgus angle of the femoral shaft distally). Considerable interspecimen variation in the angles between the transcondylar plane and the femoral center, in accord with the valgus angle of the femoral shaft distally, was also noted. The mean transcondylar valgus angle (described as the tangent of the condyles to the perpendicular of the long axis) was 3.8 degrees. In contrast, little variation among specimens was noted for the angle made by the shaft and the long axis.
An Hand von Nachuntersuchungsergebnissen werden an speziellen Fällen die Probleme der Therapie von Pseudarthrosen aufgezeigt. Sie reicht von der „äTibia pro Fibula”-Operation beim Kind bis zu der Exartikulation des Beines in Fällen mit schweren Begleitverletzungen der Gefäße und der Nerven. Die hohe Komplikationsrate von medialen Schenkelhalsfrakturen läßt beim Patienten über 60 Jahren die primäre Implantation möglichst einer Hemialloarthroplastik erwägen.
Bei der in Fehlstellung verheilten Fraktur des Unterschenkels muß bedacht werden, daß Valgus- und Innenrotationsfehlstellungen etwas besser toleriert werden als deren Gegenteil. Da an der Tibia die Korrektur nicht immer an der Stelle der primären Deformität vorgenommen werden kann, werden die Fixierungsmöglichkeiten für Korrekturosteotomien in diesem Bereich mit ihren Vor- und Nachteilen diskutiert.
Unicompartmental osteoarthritis was produced by applying varus stress to moving rabbit knee joints. Degenerative changes were confined to the medial tibial and the medial femoral articular surfaces. Within the range of varus stress used, duration appears to be more important than magnitude of varus stress in determining the severity of cartilage damage. The calcified zone remained histologically unchanged despite advanced changes in the noncalcified zone superficial to the tidemark. Intrachondral degenerative cysts were frequently found in the basilar layers of the noncalcified cartilage adjacent to the tidemark where shear stresses were likely to be highest and diffusible nutrients least available. Highly cellular cartilaginous tissue was noted in the subchondral marrow spaces in the specimens with advanced cartilage degeneration. These areas appeared to be continuous with the overlying degenerated cartilage through gaps in the calcified cartilage. Subchondral bone did not show remarkable trabecular thickening despite advanced degenerative changes in the articular cartilage.
Hindfoot (subtalar) movement and disability after fracture of the tibial shaft have been studied. One hundred patients with soundly healed fractures of the tibial shaft treated by immobilisation in a long leg plaster cast were examined at least one year after the fracture had healed. Subtalar movement was accurately measured by a special technique and the patients were questioned specifically about any disability associated with their hindfoot. Subtalar movement was limited to some degree in 72% of patients. Forty-three per cent of patients complained of symptoms related to their subtalar joint and 12% found these symptoms troublesome.
Multiapical deformities complicate the process of preoperative planning. It is necessary to determine the level of each apex of deformity to plan accurate correction. The basic principles of mechanical axis realignment and joint orientation need to be preserved. Using the joint reference lines and mechanical axis of each bone segment, one can accurately determine the apex of each deformity. Bowing deformities are multiapical angular deformities. There are two types of bowing deformities: compensated and noncompensated. Typical examples of compensated bowing are the anterolateral and posteromedial bows of the tibia. A noncompensated bow is typical of the deformity seen in rickets.
Angular deformities of the tibia or femur in the frontal plane lead to mechanical axis deviation of the lower limb and malorientation of the joints above and below the level of deformity. Accurate correction of the malalignment and of the joint orientation is important for function and to prevent joint degeneration. An accurate yet simple method to determine the apex of deformity and the type of correction required is based on the joint reference lines of the hip, knee, and ankle, and the individual mechanical axis lines of each bone segment. If the osteotomy is performed at the level of the apex of the deformity, then the only correction needed is angulation. If the osteotomy is performed at a level proximal or distal to the apex, then translation in addition to angulation is necessary to accurately correct the deformity.