Relationship of limb length inequality with radiographic knee and hip osteoarthritis

Updates in the Management of Leg Length Discrepancy: A Systematic Review

The aim of this study is to comprehensively investigate the recent literature on the management of leg length discrepancy (LLD). A thorough search of pertinent databases was done in order to find studies that satisfied the requirements for inclusion. A thorough search of PubMed, Web of Science, Scopus, and Science Direct was conducted to find pertinent literature. Rayyan Qatar Computing Research Institute (QRCI, Ar Rayyan, Qatar) was utilized during the whole operation. Eight studies, including a total of 345 patients, were included in our data, and 206 (59.7%) of them were males. Percutaneous epiphysiodesis was the surgical intervention of choice in four studies. LLD can be effectively corrected by temporary and permanent epiphysiodesis. One study reported the incidence of angular deformities following temporary epiphysiodesis. Circumferential periosteal and dual tension-band plating significantly reduced LLD, but reported the incidence of an "over-shoot" in some patients. Bilateral motion control shoes and orthotic insole both were found to improve the patient's gait and trunk symmetry, evidenced by longer and faster steps, reduced ground impact at heel strike, and lower peak plantar pressure in both limbs. Our findings confirm that no inferences about the superiority of a particular management approach for the treatment of LLD can be made. The poor quality of the studies shows that more randomized control trials and prospective studies on the subject are required.

Looking back on 30+ years of the Johnston County Osteoarthritis Project while looking forward with the Johnston County Health Study: A narrative review

Over the last 30 years, knowledge of the epidemiology of osteoarthritis (OA) has dramatically advanced, and Osteoarthritis and Cartilage has been on the forefront of disseminating research findings from large OA cohort studies, including the Johnston County OA Project (JoCoOA). The JoCoOA is a population-based, prospective longitudinal cohort that began roughly 30 years ago with a key focus on understanding prevalence, incidence, and progression of OA, as well as its risk factors, in a predominantly rural population of Black and White adults 45+ years old in a county in the southeastern United States. Selected OA results that will be discussed in this review include racial differences, lifetime risk, biomarkers, mortality, and OA risk factors. The new Johnston County Health Study will also be introduced. This new cohort study of OA and comorbid conditions builds upon current OA knowledge and JoCoOA infrastructure and is designed to reflect changes in demographics and urbanization in the county and the region.

The Influence of Temporary Epiphysiodesis of the Proximal End of the Tibia on the Shape of the Knee Joint in Children Treated for Leg Length Discrepancy

Background: Leg length discrepancy (LLD) is a common problem in the daily clinical practice of pediatric orthopedists. Surgical treatment using LLD temporary epiphysiodesis with eight-plate implants is a minimally invasive, safe, and well-tolerated procedure that provides good treatment effects with a relatively low percentage of complications. The main aim of this retrospective study was to determine the effect of epiphysiodesis on the shape of the proximal tibia. Methods: The retrospective study was based on medical records from 2010 to 2019. Radiographs taken before the epiphysiodesis and at 6-month intervals until the end of the treatment were investigated. A total of 60 patients treated for LLD were included in the study (24 girls, 36 boys). They were divided into three groups depending on the duration of the LLD treatment: group I (18 months), group II (30 months), and group III (42 months of treatment). Radiological parameters were assessed, including the roof angle (D), the slope angles (α and β), and the specific parameters of the tibial epiphysis, namely LTH (lateral tubercle height), MTH (medial tubercle height), and TW (tibial width). Results: The roof angle decreased in all the groups, which was accompanied by an increase in the β or α angle. LTH, MTH and TW also increased, and the differences before and after the treatment for the treated legs were statistically significant in all the studied groups. The greatest change in the shape of the articular surface of the proximal tibia occurred after 42 months of treatment. Conclusions: The study showed that epiphysiodesis affects the proximal tibial articular surface over prolonged treatment. Thus, there is a need for future long-term follow-up studies to elucidate the potential effects of LLD egalization.

Are percutaneous epiphysiodesis and Phemister technique effective in the treatment of leg-length discrepancy? A systematic review

Epiphysiodesis is considered the preferred treatment for children predicted to have leg length discrepancies (LLDs) 2-5 cm at maturity. The aim of this study was to systematically review the existing literature on the effectiveness of permanent epiphysiodesis for LLD treatment, and secondarily to address the reported complications of permanent epiphysiodesis techniques. This systematic review was performed according to PRISMA guidelines. We searched MEDLINE (PubMed), Embase, Cochrane Library, Web of Science and Scopus for studies on skeletally immature patients with LLD treated with permanent epiphysiodesis. The extracted outcome categories were effectiveness of epiphysiodesis (LLD measurements pre/post-operatively, successful/unsuccessful), physeal fusion/arrest, and complications that were graded on severity. Forty-nine studies (3051 patients) were included, 1550 underwent Phemister/modified Phemister epiphysiodesis and 1501 percutaneous epiphysiodesis (PE). Total successful permanent epiphysiodesis surgeries (16 studies) were 73.7% (516/700). Only 13 out of 23 studies had a mean final LLD of less than 1.5 cm. In total, 17.5% (513/2936) of complications were reported. 57 angular deformities were reported (1.9%). Phemister technique had higher percentage of complications (39%) than PE (19.1%) in total, but when failure to achieve adequate reduction in LLD was not included, complication rates for both were close to 14%. However, severe complications were 10.2% for Phemister group and 5.1% for PE. The high complication rates and the relative low success rate call for optimization of the timing and the applied techniques when treating LLD with permanent epiphysiodesis. Phemister technique was found to have higher percentage of severe complications than PE. Registration: PROSPERO (CRD42023435177).

The immediate effect of simulating leg-length discrepancy on spinal posture and pelvic position: a cross-over designed study

Leg-length discrepancy (LLD) is a common condition that may cause posture changes and clinical consequences. Rasterstereography is a valid and reliable method that analyzes posture without radiation exposure and invasive procedures. This study aimed to assess the immediate effect of artificial LLD on pelvic position and spinal posture in athletes. Twenty-four elite karate athletes (14 men, 10 women) were included in the study. Sagittal imbalance, coronal imbalance, pelvic obliquity, pelvic torsion angle, thoracic kyphosis angle and lumbar lordosis angle were measured at different artificial LLD heights (5 -10 -15 -20 mm). Statistical analysis was performed with One-Way ANOVA with repeated measures or Friedman test. In cases where there were significant differences, pairwise comparisons were performed with least significant differences (LSD) test or Wilcoxon signed rank test. There were statistically significant differences in pelvic obliquity (p = 0.001), pelvic torsion (p = 0.001) and lumbar lordosis (p = 0.001) with varying LLD. However, there was no significant difference in sagittal imbalance, coronal imbalance and thoracic kyphosis angle. It has been observed that even a 5-mm LLD causes pelvic position and spinal posture changes. Future studies detecting these changes in populations with LLD via rastersterography may prevent possible musculoskeletal disorders.

A novel measurement approach to dynamic change of limb length discrepancy using deep learning and wearable sensors

The accurate identification of dynamic change of limb length discrepancy (LLD) in non-clinical settings is of great significance for monitoring gait function change in people's everyday lives. How to search for advanced techniques to measure LLD changes in non-clinical settings has always been a challenging endeavor in recent related research. In this study, we have proposed a novel approach to accurately measure the dynamic change of LLD outdoors by using deep learning and wearable sensors. The basic idea is that the measurement of dynamic change of LLD was considered as a multiple gait classification task based on LLD change that is clearly associated with its gait pattern. A hybrid deep learning model of convolutional neural network and long short-term memory (CNN-LSTM) was developed to precisely classify LLD gait patterns by discovering the most representative spatial-temporal LLD dynamic change features. Twenty-three healthy subjects were recruited to simulate four levels of LLD by wearing a shoe lift with different heights. The Delsys TrignoTM system was implemented to simultaneously acquire gait data from six sensors positioned on the hip, knee and ankle joint of two lower limbs respectively. The experimental results showed that the developed CNN-LSTM model could reach a higher accuracy of 93.24% and F1-score of 93.48% to classify four different LLD gait patterns when compared with CNN, LSTM, and CNN-gated recurrent unit(CNN-GRU), and gain better recall and precision (more than 92%) to detect each LLD gait pattern accurately. Our model could achieve excellent learning ability to discover the most representative LLD dynamic change features for classifying LLD gait patterns accurately. Our technical solution would help not only to accurately measure LLD dynamic change in non-clinical settings, but also to potentially find out lower limb joints with more abnormal compensatory change caused by LLD.

Caring for the injured: Exploring the immediate and long-term consequences of injury in medieval Cambridge, England

OBJECTIVE

To combine paleopathological and biomechanical analysis to reconstruct the impact that a severe skeletal injury had on an individual's ability to function and participate in medieval society.

MATERIALS

Three medieval individuals from Cambridge, England with ante-mortem fractures to the lower limb were analyzed.

METHODS

Plain X-rays were used to determine the degree of malunion, rotation and overlap of each fracture. Cortical bone architecture of the injured individuals and 28 uninjured controls were analyzed using micro-computed tomography (µCT). Clinical and functional consequences were examined using the Bioarcheology of Care framework.

RESULTS

The mechanism of injury, the secondary complications, and the extent of the care received was reconstructed for each individual. Bilateral asymmetry in the cortical bone architecture revealed the long-term alterations to each individual's gait.

CONCLUSION

Each of these individuals survived a severe injury resulting in chronic physical impairment, though not all would have been considered 'disabled'.

SIGNIFICANCE

This research contributes to the discussion about medieval care provision and social constructions of disability by illustrating how an interdisciplinary approach provides insight into the experiences of those with physical impairments. The integration of µCT imaging within the Bioarcheology of Care model is a novel approach with great potential for application across the field.

LIMITATIONS

Biomechanical analysis was restricted to cortical geometry.

SUGGESTIONS FOR FUTURE RESEARCH

Further study of bilateral asymmetry in trabecular architecture could complement our understanding of altered loading modalities in past societies.

Application of three-dimensional printed navigation templates to correct lower limb deformities in children by the guided growth technique

Objective

Currently, individualized navigation templates are rarely applied in pediatric orthopedic surgery. This study aimed to explore the potential of navigation templates obtained using computer-aided design and three-dimensional (3D) printing to correct lower limb deformities in children by the guided growth technique.

Methods

We prospectively studied 45 children with leg length discrepancy (LLD) or lower limb angular deformities, who underwent guided growth surgery involving 8-plate. In total, 21 and 24 children were included in the navigation template (group A) group and in the traditional surgery (group B) group, respectively. Mimics software was used for designing and printing navigation templates. The operation time, X-ray radiation exposure, damage to cartilage, and postoperative complications were recorded.

Results

The mean operation time in groups A and B were 20.78 and 28.39 min, respectively, and the difference was statistically significant. Compared with group B, the intraoperative exposure of X-rays in group A was reduced by 25% on average. After 9–24 months of follow-up, the deformities were corrected in both groups. No significant differences in the treatment effect were noted between the groups, and no complications occurred.

Conclusions

Using the individualized navigation template in the guided growth technique made the surgical procedure convenient and simple to perform. In addition, the operation time and intraoperative exposure to X-rays were reduced. We consider that 3D printed navigation templates can facilitate the accurate completion of corrective surgeries for lower limb deformities in children, which is worthy of promotion and application.

Factors influencing inconsistent leg length discrepancy in dysplastic hip osteoarthritis: a retrospective study

BACKGROUND

We aimed to examine the inconsistency between radiographic leg length discrepancy (R-LLD) and perceived LLD (P-LLD) in patients with dysplastic hip osteoarthritis and to evaluate the factors that can cause such inconsistency.

METHODS

We conducted a retrospective study on 120 patients. An inconsistent LLD was defined as a condition in which the P-LLD was shorter than the R-LLD by > 5 mm. We compared relevant data on the general characteristics of the patients and the radiological findings between consistent (group E, 92 cases [76.7%]) and inconsistent LLDs (group S, 28 cases [23.3%]).

RESULTS

The number of patients with a history of hip surgery on the affected side and the Japanese Orthopedic Association classification pain scores were significantly higher in group S than in group E (32.1% vs. 10.8%, respectively; P = 0.015, and 21.7 ± 7.0 vs. 17.5 ± 8.2, respectively; P = 0.036). The pelvic oblique angle and length of the R-LLD were significantly higher in group S than in group E (2.9 ± 2.5° vs. 0.3 ± 2.3°, respectively; P < 0.01, and 17.2 ± 8.9 mm vs. 6.3 ± 8.4 mm, respectively; P < 0.01). Multivariate logistic analysis revealed that the pelvic oblique angle (odds ratio [OR]: 1.80, 95% confidence interval [CI]: 1.28-2.52; P < 0.01) and length of the R-LLD (OR: 2.75, 95% CI: 1.24-6.12; P = 0.013) were independent risk factors of inconsistent LLD.

CONCLUSION

The pelvic oblique angle and a long R-LLD were independent risk factors of inconsistent LLD in patients with dysplastic hip osteoarthritis. Therefore, hip surgeons should consider P-LLD rather than R-LLD to understand the need for conservative intervention.

The Effect of Simulated Leg-Length Discrepancy on the Dynamic Parameters of the Feet during Gait-Cross-Sectional Research

Background: The effect of Leg-Length Discrepancy (LLD) on dynamic gait parameters has been extensively discussed. Podobarography is the study of foot-to-ground pressure distribution. It has been used to test plantar footprint deviations that could reveal pathology. Purpose: The aim of this study is to determine the effects of simulated LLD on dynamic gait parameters measured with a pressure platform in healthy subjects. Methods: Thirty-seven healthy subjects participated in observational cross-sectional research. A procedure was performed to capture the dynamic parameters of each participant under five different simulated LLD conditions. Support time, mean pressure, and peak pressure measures were registered on three trials for each foot and LLD level per session. An analysis of variance (ANOVA) test for repeated measures was performed to check for differences between the different simulated LLD levels. Results: The stance time of the short leg had no significant changes. The stance time of the long leg increased by 3.51% (p < 0.001), mean pressure of the short leg increased by 1.23% (p = 0.005), and decreased by 5.89% in the long leg (p < 0.001). Peak pressure of the short leg decreased by 2.58% (p = 0.031) and the long leg decreased by 12.11% (p < 0.001). Conclusions: This study demonstrates that increasing LLD causes an asymmetrical foot-loading pattern, with decreased mean and peak pressure on the longer limb, and consequently an overload on the short side. Furthermore, an increasing LLD causes increased stance time on the long leg.

Comparison of the prevalence of myofascial trigger points of muscles acting on knee between patients with moderate degree of knee osteoarthritis and healthy matched people

INTRODUCTION

Trigger points have been implicated in the development of several musculoskeletal disorders. Trigger points harbored in lower limb muscles might represent a ubiquitous source of pain in patients with knee osteoarthritis (OA). This study was carried out to evaluate the prevalence of Myofascial Trigger Points (MTrPs) in muscles acting on the knee in patients with OA.

METHODS

Thirty-seven patients aged at least 55 years old with a moderate degree of OA (grade III of Kellgren and Lawrence scale) were recruited. Thirty asymptomatic people, matched on age and body mass index, were considered as the control group. Ten muscles acting on the knee joint were selected. Taut bands were also identified using a skin rolling method. A pressure of 3 kg/cm² was used to identify myofascial trigger points in all muscles except the popliteus (8 kg/cm²).

RESULTS

Chi-square was performed to compare the prevalence of trigger points between the groups. The McNemar test was administered to compare the prevalence of trigger points in the right and left sides of participants. Prevalence of the trigger points was significantly higher in patients with knee OA compared with asymptomatic people in all muscles except for right (p = 0.17) and left (p = 0.41) rectus femoris, right (p = 0.61) and left (p = 0.22) sartorius and left biceps femoris (p = 0.08). Comparison of the prevalence of MTrPs bilaterally revealed that only the right and left sartorius differed significantly (p = 0.008).

CONCLUSIONS

The prevalence of MTrPs in the muscles acting on the knee joint is higher in patients with a moderate degree of knee OA compared with asymptomatic subjects.

Osteonecrosis of the Femoral Medial Condyle Due to Leg Length Discrepancy After A Traffic Accident

Untreated leg length discrepancy can cause spontaneous osteonecrosis of the knee, which is associated with subchondral insufficiency fractures of the knee and progression or onset of osteoarthritis of the knee. Spontaneous osteonecrosis of the knee can be secondary to cartilage loss or additional subchondral changes. A 40-year-old female underwent opening-wedge high tibial osteotomy and osteochondral grafting for osteonecrosis of the femoral medial condyle and osteoarthritis of the knee caused by leg length discrepancy after a traffic accident. High tibial osteotomy and cartilage restoration are often considered for the treatment of knee osteonecrosis with cartilage damage in younger patients.

The Actions of IGF-1 in the Growth Plate and Its Role in Postnatal Bone Elongation

PURPOSE OF REVIEW

Bone elongation is a complex process driven by multiple intrinsic (hormones, growth factors) and extrinsic (nutrition, environment) variables. Bones grow in length by endochondral ossification in cartilaginous growth plates at ends of developing long bones. This review provides an updated overview of the important factors that influence this process.

RECENT FINDINGS

Insulin-like growth factor-1 (IGF-1) is the major hormone required for growth and a drug for treating pediatric skeletal disorders. Temperature is an underrecognized environmental variable that also impacts linear growth. This paper reviews the current state of knowledge regarding the interaction of IGF-1 and environmental factors on bone elongation. Understanding how internal and external variables regulate bone lengthening is essential for developing and improving treatments for an array of bone elongation disorders. Future studies may benefit from understanding how these unique relationships could offer realistic new approaches for increasing bone length in different growth-limiting conditions.

Brief Report: Leg Length Inequality and Hip Osteoarthritis in the Multicenter Osteoarthritis Study and the Osteoarthritis Initiative

OBJECTIVE

Studies suggest that persons with a leg length inequality (LLI) of ≥2 cm have an increased risk of developing knee osteoarthritis (OA) in that limb. The present study was undertaken to examine whether LLI also confers an increased risk of hip OA.

METHODS

Using long limb radiographs from subjects in the Multicenter Arthritis Study (MOST) and the Osteoarthritis Initiative (OAI), we measured LLI and scored hip radiographs that were obtained at baseline and 3-5-year follow-up. The associations of LLI of ≥1 cm and LLI of ≥2 cm with radiographic hip OA were examined cross-sectionally and longitudinally, assessing risk in shorter limbs and longer limbs compared to limbs from subjects with no LLI. We carried out logistic regression analyses with generalized estimating equations and adjusted for age, sex, body mass index, height, and cohort of origin.

RESULTS

There were 1,966 subjects from the MOST and 2,627 subjects from the OAI. Twelve percent had LLI of ≥1 cm and 1% had LLI of ≥2 cm. For LLI ≥1 cm, the adjusted odds ratio for prevalent hip OA in the shorter leg was 1.47 (95% confidence interval [95% CI] 1.07-2.02) and for LLI ≥2 cm, it was 2.15 (95% CI 0.87-5.34). For LLI ≥1 cm, the odds of incident hip OA in the shorter leg were 1.39 (95% CI 0.81-2.39) while for LLI ≥2 cm, they were 4.20 (95% CI 1.26-14.03). We found no increased risk of hip OA in longer limbs.

CONCLUSION

Our findings suggest that, as with knee OA, legs that are at least 2 cm shorter than the contralateral leg are at increased risk of hip OA.

Can osteophytes be used as age at death estimators? Testing correlations in skeletonized human remains with known age-at-death

Age-at-death estimation is one of the major challenges when establishing an adult skeleton biological profile. The presence of degenerative joint changes - e.g. osteophytes - has been regarded as a good postmaturity age indicator. This study assessed if a clear relationship between age and osteophytes exists. To accomplish this goal, a total of 16 joint surfaces, from the shoulder, elbow, wrist, hip, knee, and ankle, were examined in 604 adult individuals, of both sexes from two Portuguese Identified collections. Individuals had between 20 and 98 year old at death. Statistically significant results were found between age-at-death and degrees of severity of osteophytes throughout all the articular surfaces analyzed (p>0.001). However, the strength of the correlation varies from moderate to low in the majority of the joints, for both sexes. The only strong correlation effects (r=0.567 in females and r=0.552 in males) were found associated with the left and right glenoid cavity in females and males respectively. More noticeable changes were consistently found in association with older individuals (>62 years old). Results indicate that significant relationships exist between age and the presence of osteophytes in the joint margins. However, correlation effects were low to moderate in most cases, therefore the use of osteophytes to predict age-at-death is not without significant error of interpretation.

Three-dimensional limb lengthening after total knee arthroplasty in a simulation study

OBJECTIVES

Limb lengthening after total knee arthroplasty (TKA) has been reported in some cases, all of which were evaluated using two-dimensional images. To our knowledge, no case has been evaluated using three-dimensional (3D) images. We investigated 3D limb lengthening after TKA.

METHODS

We simulated 100 varus knees using 3D templating software. Virtual TKA was performed to maintain the original joint line by conducting a measured-resection technique. We examined the relationships of 3D distance between the femoral head center and ankle center before and after TKA, degree of hip-knee-ankle angle (HKA) improvement, and degree of flexion contracture angle improvement.

RESULTS

All cases showed limb lengthening (average, 9.4 ± 6.0 mm). The coefficients of correlation with limb lengthening and the degree of HKA improvement and the degree of flexion contracture angle improvement were good (0.730 and 0.751, respectively). The correlation between the degree of total improvement (the degree of HKA improvement + the degree of flexion contracture angle improvement) and limb lengthening was strong (r = 0.896).

CONCLUSION

The expected limb lengthening when performing measured-resection TKA is expressed as 0.58 × (the degree of HKA improvement + the degree of flexion contracture angle improvement) mm and is a useful index.

Percutaneous Epiphysiodesis Using Transphyseal Screws: a Case Series Demonstrating High Efficacy

BACKGROUND

Percutaneous epiphysiodesis using transphyseal screws (PETS) has been associated with implant failure, implant prominence, angular deformities, and delayed growth inhibition.

QUESTIONS/PURPOSES

The aim of this study was to assess the complication rate and efficacy (defined as actual growth inhibition divided by expected growth inhibition) of PETS and to identify factors associated with improved efficacy.

METHODS

Patients who underwent distal femoral and/or proximal tibial PETS between January 2007 and June 2014 were identified. Complications, efficacy, and final limb-length discrepancy (LLD) were calculated using multipliers and inhibition rates based on previous growth. Associations between efficacy and screw insertion angle (SIA), body mass index, and number of threads crossing the physis were calculated.

RESULTS

Eight-two patients (126 treated physes) were included. The mean pre-operative LLD was 27.7 mm (SD = 7.5). Following epiphysiodesis, 15 had temporary pain (18%), five had temporary effusion (6.1%), four had broken implants (4.9%), four developed mild angulation (4.9%), and three had failed epiphysiodesis requiring revision (3.7%). Thirty-one underwent screw removal (n = 31, 38%). Mean LLD at maturity was 17.3 mm (SD = 5.8 mm). Mean efficacy at the distal femur was 97% (SD = 46%), at the proximal tibia was 108% (SD = 66%) and was 103% (SD = 57%) overall. Increased screw threads across the lateral proximal tibial physis (Spearman's correlation coefficient = 0.67; 95% CI = 0.40-0.94) and higher BMI (Spearman's correlation coefficient = 0.55; 95% CI = 0.34-0.77) were positively associated with increased efficacy.

CONCLUSIONS

The efficacy of PETS may be more favorable than previously reported. Only 3.7% had serious complications requiring revision epiphysiodesis, lower than previous reports. Attention to sufficient screw threads across the physis may be important in optimizing PETS results.

Association of Mild Leg Length Discrepancy and Degenerative Changes in the Hip Joint and Lumbar Spine

OBJECTIVE

The purpose of this study was to evaluate the correlation between mild leg length discrepancy (LLD) and degenerative joint disease (DJD) or osteoarthritis.

METHODS

We evaluated standard postural lumbopelvic radiographs from 255 adults (121 women and 134 men) who had presented with spinal pain for chiropractic care. Symmetry of femoral head diameters was used to exclude magnification errors. Pearson's partial correlation was used to control for age and derive effect sizes for LLD on DJD in the hip and lower lumbar motion segments. Krippendorff's α was used for intraobserver and interobserver reliability.

RESULTS

A strong correlation was found between LLD and hip DJD in men (r = 0.532) and women (r = 0.246). We also found a strong correlation between LLD and DJD at the L5-S1 motion segment in men (r = 0.395) and women (r = 0.246). At the L4-5 spinal level this correlation was much attenuated in men (r = 0.229) and women (r = 0.166).

CONCLUSIONS

These findings suggest an association between LLD and hip and lumbar DJD. Cause-effect relationships between mild LLD and DJD deserve to be properly evaluated in future longitudinal cohort studies.

Closing the growth plate: a review of indications and surgical options

PURPOSE OF REVIEW

The purpose is to review the indications for epiphysiodesis in the treatment of pediatric limb length discrepancies; provide an update on current diagnostic, planning, and surgical techniques; and to introduce possible future alternatives.

RECENT FINDINGS

Retrospective comparative studies have failed to demonstrate superiority of one epiphysiodesis technique over the others. EOS low-dose biplanar X-ray and smartphone growth prediction applications are improving our ability to diagnose and plan treatment for leg length discrepancy. Arthroscopically guided percutaneous epiphysiodesis and radiofrequency ablation are newer techniques that are still under investigation.

SUMMARY

Epiphysiodesis is the treatment of choice for children with predicted leg length discrepancies between 2-5 cm, provided that the physes are open with sufficient growth remaining. The most common epiphysiodesis techniques are performed percutaneously and either ablate the physis with drills/curettes or use metal implants to tether the physis and prevent further growth. Surgical treatment is typically ambulatory in nature, and allows for early return to weight bearing. In modern series, complication rates are less than 10%, with the majority being minor complications. Further high-quality prospective research is needed to determine the optimal epiphysiodesis surgical technique.

State of the evidence

PURPOSE OF REVIEW

This review focuses on recent studies of osteoarthritis epidemiology, including research on prevalence, incidence, and a broad array of potential risk factors at the person level and joint level.

RECENT FINDINGS

Studies continue to illustrate the high impact of osteoarthritis worldwide, with increasing incidence. Person-level risk factors with strong evidence regarding osteoarthritis incidence and/or progression include age, sex, socioeconomic status, family history, and obesity. Joint-level risk factors with strong evidence for incident osteoarthritis risk include injury and occupational joint loading; the associations of injury and joint alignment with osteoarthritis progression are compelling. Moderate levels of physical activity have not been linked to increased osteoarthritis risk. Some topics of high recent interest or emerging evidence for association with osteoarthritis include metabolic pathways, vitamins, joint shape, bone density, limb length inequality, muscle strength and mass, and early structural damage.

SUMMARY

Osteoarthritis is a complex, multifactorial disease, and there is still much to learn regarding mechanisms underlying incidence and progression. However, there are several known modifiable and preventable risk factors, including obesity and joint injury; efforts to mitigate these risks can help to lessen the impact of osteoarthritis.

Assessing risk factors for early hip osteoarthritis in activity-related hip pain: a Delphi study

OBJECTIVE

Hip pain and injury as a result of activity can lead to the development of early hip osteoarthritis (OA) in susceptible individuals. Our understanding of the factors that increase susceptibility continues to evolve. The ability to clearly identify individuals (and cohorts) with activity-related hip pain who are at risk of early hip OA is currently lacking. The purpose of this study was to gain expert consensus on which key clinical measures might help predict the risk of early hip OA in individuals presenting with activity-related hip pain. The agreed measures would constitute a standardised approach to initial clinical assessment to help identify these individuals.

METHODS

This Dephi study used online surveys to gain concordance of expert opinion in a structured process of 'rounds'. In this study, we asked 'What outcome measures are useful in predicting hip OA in activity-related hip pain?' The Delphi panel consisted of experts from sport and exercise medicine, orthopaedics, rheumatology, physiotherapy and OA research.

RESULTS

The study identified key clinical measures in the history, examination and investigations (plain anteroposterior radiograph and femoroacetabular impingement views) that the panel agreed would be useful in predicting future risk of hip OA when assessing activity-related hip pain. The panel also agreed that certain investigations and tests (eg, MR angiography) did not currently have a role in routine assessment. There was a lack of consensus regarding the role of MRI, patient-reported outcome measures (PROMs) and certain biomechanical and functional assessments.

CONCLUSIONS

We provide a standardised approach to the clinical assessment of patients with activity-related hip pain. Assessment measures rejected by the Delphi panel were newer, more expensive investigations that currently lack evidence. Assessment measures that did not reach consensus include MRI and PROMs. Their role remains ambiguous and would benefit from further research.

Leg length discrepancy and osteoarthritis in the knee, hip and lumbar spine

Osteoarthritis (OA) is an extremely common condition that creates substantial personal and health care costs. An important recognised risk factor for OA is excessive or abnormal mechanical joint loading. Leg length discrepancy (LLD) is a common condition that results in uneven and excessive loading of not only knee joints but also hip joints and lumbar motion segments. Accurate imaging methods of LLD have made it possible to study the biomechanical effects of mild LLD (LLD of 20mm or less). This review examines the accuracy of these methods compared to clinical LLD measurements. It then examines the association between LLD and OA of the joints of the lower extremity. More importantly, it addresses the largely neglected association between LLD and degeneration of lumbar motion segments and the patterns of biomechanical changes that accompany LLD. We propose that mild LLD may be an important instigator or contributor to OA of the hip and lumbar spine, and that it deserves to be rigorously studied in order to decrease OA's burden of disease.

Development and validation of formulae to predict leg length following medial opening-wedge osteotomy of the proximal tibia with hemicallotasis

BACKGROUND

A medial open-wedge osteotomy of the proximal tibia with hemicallotasis (HCO) affects the relative coronal alignment of the femur and tibia with respect to the floor; this also potentially reflects a change in leg length.

PURPOSE

The aims of this study are to develop and verify formulae for predicting the postoperative whole leg length (WLL) in HCO.

METHODS

We analyzed a training set of 25 HCOs in 25 patients. Formulae for predicting the postoperative leg length were developed using various factors including the length and coronal alignment of the femur and tibia, the length of the proximal or distal fragment from the tibial osteotomy site, the femoro-tibial angle, and the correction angle. The formulae were then verified using the interclass correlation coefficient in an independent consecutive set of 25 HCOs.

RESULTS

Significant postoperative increases in tibial bone length and WLL were noted with no postoperative change in femoral bone length. Furthermore, the coronal alignments of femoral and tibial bone axes were significantly abducted. For the formulae for predicting postoperative WLL developed in the training set, the interclass correlation coefficients between the predicted values and the real radiographic measurements in the validation set were more than 0.90, showing great consistency.

CONCLUSION

The mathematical models established in this study seemed to predict almost completely the change in leg length after HCO. Our results suggest that these formulae may offer accurate, extremely useful information about the postoperative possibility of leg lengthening for patients planning an HCO.

LEVEL OF EVIDENCE

Therapeutic case series; level 4.

Association between leg length discrepancy and posterior tibial tendon dysfunction

BACKGROUND

Leg length discrepancy (LLD) is associated with a variety of orthopaedic disorders and biomechanical gait changes that involve possible overload of the posterior tibial tendon (PTT). In view of the biomechanical disturbances induced by LLD, an association may exist between LLD and PTT dysfunction (PTTD).

PURPOSE

To compare the frequency and magnitude of LLD between subjects with and without PTTD and ascertain whether associations exist between clinical features and presence of dysfunction.

STUDY DESIGN

Case-control study.

METHODS

A total of 118 patients with a diagnosis of PTTD were seen between January 2009 and September 2012 and compared with 118 gender-matched and race-matched volunteers. The frequency of LLD, the mean absolute LLD, and the mean relative LLD were measured by conventional (radiographic) or computed tomography scanography and compared between cases and controls.

RESULTS

The prevalence of LLD and mean absolute and relative LLD values were significantly greater in the case group (94.9%, 5.64 mm and 7.36%, respectively) than in the control group (79.7%, 3.28 mm and 4.18%, respectively) (P < .001).

CONCLUSION

The findings of this study demonstrate a relationship between LLD and PTTD. In light of the major biomechanical changes it induces, LLD may be a predisposing factor for development of PTTD.

Pilot study of the impact that bilateral sacroiliac joint manipulation using a drop table technique has on gait parameters in asymptomatic individuals with a leg length inequality

PURPOSE

The purpose of this study was to pilot test our study procedures and estimate parameters for sample size calculations for a randomized controlled trial to determine if bilateral sacroiliac (SI) joint manipulation affects specific gait parameters in asymptomatic individuals with a leg length inequality (LLI).

METHODS

Twenty-one asymptomatic chiropractic students engaged in a baseline 90-second walking kinematic analysis using infrared Vicon® cameras. Following this, participants underwent a functional LLI test. Upon examination participants were classified as: left short leg, right short leg, or no short leg. Half of the participants in each short leg group were then randomized to receive bilateral corrective SI joint chiropractic manipulative therapy (CMT). All participants then underwent another 90-second gait analysis. Pre- versus post-intervention gait data were then analyzed within treatment groups by an individual who was blinded to participant group status. For the primary analysis, all p-values were corrected for multiple comparisons using the Bonferroni method.

RESULTS

Within groups, no differences in measured gait parameters were statistically significant after correcting for multiple comparisons.

CONCLUSIONS

The protocol of this study was acceptable to all subjects who were invited to participate. No participants refused randomization. Based on the data collected, we estimated that a larger main study would require 34 participants in each comparison group to detect a moderate effect size.

Pilot study of the impact sacroiliac joint manipulation has on walking kinematics using motion analysis technology

OBJECTIVE

The purpose of this study was to evaluate the feasibility of engaging in a series of larger studies measuring the effect of sacroiliac joint manipulation on walking kinematics using motion analysis technology.

METHODS

Twelve college students engaged in a baseline 90-second gait analysis at 1.5 mph using infrared VICON cameras. Following this, they underwent a prone heel comparison test for functional leg length inequality. Upon examination, participants were then classified as follows: left short leg, right short leg, or no short leg. Participants in each of the 2 short leg branches of this study were then randomized to receive either chiropractic manipulative therapy to the posterior superior iliac spine on the short limb side or no manipulation. Recruitment was ongoing for this pilot study until 1 participant was recruited in each of the following 5 comparative study groups: left short leg-manipulation, left short leg-no manipulation (control 1), right short leg-manipulation, right short leg-no manipulation (control 2), and no short leg (control 3). All participants then underwent another 90-second gait analysis. Data were then grouped and submitted to a blinded biomechanist to determine if there were any unique biomechanical differences between the groups.

RESULTS

No statistically significant differences were measured because of this being a pilot study with a small sample size.

CONCLUSIONS

The data from this study indicate that a series of larger studies with this design is feasible.

Epidemiology of osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis in the United States and is a leading cause of disability. It is typically defined in epidemiologic studies by radiographic findings and consideration of symptoms. Its incidence and prevalence are rising, likely related to the aging of the population and increasing obesity. Risk factors for OA include numerous person-level factors, such as age, sex, obesity, and genetics, as well as joint-specific factors that are likely reflective of abnormal loading of the joints. In studying OA, several methodologic challenges exist that can hamper our ability to identify pertinent relationships.

Epidemiology of osteoarthritis and associated comorbidities

Osteoarthritis (OA) is the most common cause of walking-related disability among older adults in the United States, and the prevalence and incidence of OA are increasing rapidly. Systemic and local risk factors for knee OA have been identified, and obesity and joint injury appear to be the strongest risk factors that are both modifiable and have the potential for substantial impact on a population level. The risk factors for functional decline and disability in persons with symptomatic OA have been examined in relatively few studies. The course of functional decline in persons with symptomatic OA on a population level is generally one of stable to slowly deteriorating function, but on an individual level, many patients maintain function or improve during the first 3 years of follow-up. Obesity stands out as one of few modifiable risk factors of OA that also is a potentially modifiable predictor of functional decline. Physical activity also appears to have a substantial protective impact on future OA-related disability. Further epidemiologic studies and randomized controlled trials are needed to prioritize prevention through targeting these modifiable risk factors for OA and related disability.

Magnitude of limb lengthening after primary total knee arthroplasty

Patients will often perceive a change in lower limb length after total knee arthroplasty (TKA). From this observed finding, we asked how frequently does a change in limb length occur after TKA. Preoperative and postoperative full-length standing radiographs were obtained for 102 knees in 98 patients who underwent TKA. Digital radiography software was used to measure the mechanical axis and limb length of the operative and nonoperative legs. Overall, 83% of the knees measured showed an increase in limb length after TKA. Preoperative varus alignment was associated with an average lengthening of 5.2 mm. Preoperative valgus alignment was associated with an average lengthening of 8.4 mm. Patients with a valgus deformity greater than 10° demonstrated the greatest average lengthening. It is the conclusion of this study that limb lengthening occurs frequently after TKA, back to a length similar to the nonoperative limb.

Osteoarthritis prevention

PURPOSE OF REVIEW

We discuss recent published epidemiologic data regarding risk factors for incident and progressive knee osteoarthritis and related knee pain to identify targets for primary and secondary prevention. We also discuss recently identified methodologic challenges to the study of knee osteoarthritis, particularly osteoarthritis progression.

RECENT FINDINGS

Recent epidemiologic studies and systematic reviews of knee osteoarthritis have confirmed that being overweight and obese, and knee injuries increase the risk for incident knee osteoarthritis. Biomechanical risk factors such as leg-length inequalities and malalignment require further study. Obesity also appears to play a role in accelerating osteoarthritis worsening. However, with the exception of malalignment, no risk factors for knee osteoarthritis progression have been identified. Novel approaches to the study of knee pain have demonstrated a strong association between structural abnormalities and knee pain, contrary to the 'so-called' structure-symptom discordance, as well as between fluctuations of knee pain with changes in specific structural lesions. A number of methodologic issues, including conditioning on an intermediate stage of disease and depletion of susceptibles may explain, in part, the difficulty in identifying risk factors for knee osteoarthritis.

SUMMARY

There is strong epidemiologic evidence that being overweight or obese and knee injury are associated with increased risk of developing knee osteoarthritis. Further study is required to confirm associations of leg-length inequality and malalignment with incident knee osteoarthritis. Few new risk factors for progression of knee osteoarthritis have been identified in the past few years. Without such knowledge, secondary prevention of osteoarthritis remains challenging.

Epidemiology of osteoarthritis

Osteoarthritis (OA) is the most common joint disorder in the United States. Symptomatic knee OA occurs in 10% men and 13% in women aged 60 years or older. The number of people affected with symptomatic OA is likely to increase due to the aging of the population and the obesity epidemic. OA has a multifactorial etiology, and can be considered the product of an interplay between systemic and local factors. Old age, female gender, overweight and obesity, knee injury, repetitive use of joints, bone density, muscle weakness, and joint laxity all play roles in the development of joint OA, particularly in the weight-bearing joints. Modifying these factors may reduce the risk of OA and prevent subsequent pain and disability.

Epidemiology of osteoarthritis

Osteoarthritis (OA) is the most common joint disorder in the United States. Symptomatic knee OA occurs in 10% men and 13% in women aged 60 years or older. The number of people affected with symptomatic OA is likely to increase due to the aging of the population and the obesity epidemic. OA has a multifactorial etiology, and can be considered the product of an interplay between systemic and local factors. Old age, female gender, overweight and obesity, knee injury, repetitive use of joints, bone density, muscle weakness, and joint laxity all play roles in the development of joint OA, particularly in the weight-bearing joints. Modifying these factors may reduce the risk of OA and prevent subsequent pain and disability.

Hazard of incident and progressive knee and hip radiographic osteoarthritis and chronic joint symptoms in individuals with and without limb length inequality

OBJECTIVE

To examine the hazard of incident and progressive radiographic osteoarthritis (rOA) and chronic joint symptoms at the hip and knee by limb length inequality (LLI) in a large, community-based sample.

METHODS

A longitudinal cohort completed baseline (1991-97) clinical evaluation and identical followup assessment (1999-2003) (median followup time 5.9 yrs, range 3.0-13.1 yrs). LLI was defined at baseline as a measured difference between limbs ≥ 2 cm. The study groups with LLI data comprised 1583 participants with paired (baseline and followup) knee radiographs and 1453 participants with paired hip radiographs. Multivariable Cox regression models were used to examine the hazard of incident and progressive knee and hip rOA and chronic joint symptoms, with adjustment for demographic and clinical factors.

RESULTS

The hazard of developing incident knee or hip rOA was 20%-30% higher and of developing progressive knee or hip rOA was 35%-83% higher among participants with LLI, but results were only statistically significant for progressive knee rOA (adjusted hazard ratio = 1.83, 95% CI 1.10-3.05). The hazards of progressive chronic knee symptoms and incident and progressive chronic hip symptoms were 13%-59% higher among participants with LLI, but were not statistically significant.

CONCLUSION

LLI was associated with progressive knee rOA and was nonsignificantly associated with incident knee or hip rOA and progressive hip rOA, progressive chronic knee symptoms, and incident and progressive chronic hip symptoms. Longer studies may strengthen these associations and help determine whether LLI is a risk factor or marker of these outcomes.

Association of leg-length inequality with knee osteoarthritis: a cohort study

BACKGROUND

Leg-length inequality is common in the general population and may accelerate development of knee osteoarthritis.

OBJECTIVE

To determine whether leg-length inequality is associated with prevalent, incident, and progressive knee osteoarthritis.

DESIGN

Prospective observational cohort study.

SETTING

Population samples from Birmingham, Alabama, and Iowa City, Iowa.

PATIENTS

3026 participants aged 50 to 79 years with or at high risk for knee osteoarthritis.

MEASUREMENTS

The exposure was leg-length inequality, measured by full-limb radiography. The outcomes were prevalent, incident, and progressive knee osteoarthritis. Radiographic osteoarthritis was defined as Kellgren and Lawrence grade 2 or greater, and symptomatic osteoarthritis was defined as radiographic disease in a consistently painful knee.

RESULTS

Compared with leg-length inequality less than 1 cm, leg-length inequality of 1 cm or more was associated with prevalent radiographic (53% vs. 36%; odds ratio [OR], 1.9 [95% CI, 1.5 to 2.4]) and symptomatic (30% vs. 17%; OR, 2.0 [CI, 1.6 to 2.6]) osteoarthritis in the shorter leg, incident symptomatic osteoarthritis in the shorter leg (15% vs. 9%; OR, 1.7 [CI, 1.2 to 2.4]) and the longer leg (13% vs. 9%; OR, 1.5 [CI, 1.0 to 2.1]), and increased odds of progressive osteoarthritis in the shorter leg (29% vs. 24%; OR, 1.3 [CI, 1.0 to 1.7]).

LIMITATIONS

Duration of follow-up may not be long enough to adequately identify cases of incidence and progression. Measurements of leg length, including radiography, are subject to measurement error, which could result in misclassification.

CONCLUSION

Radiographic leg-length inequality was associated with prevalent, incident symptomatic, and progressive knee osteoarthritis. Leg-length inequality is a potentially modifiable risk factor for knee osteoarthritis.

PRIMARY FUNDING SOURCE

National Institute on Aging.

Association of leg-length inequality with knee osteoarthritis: a cohort study

BACKGROUND

Leg-length inequality is common in the general population and may accelerate development of knee osteoarthritis.

OBJECTIVE

To determine whether leg-length inequality is associated with prevalent, incident, and progressive knee osteoarthritis.

DESIGN

Prospective observational cohort study.

SETTING

Population samples from Birmingham, Alabama, and Iowa City, Iowa.

PATIENTS

3026 participants aged 50 to 79 years with or at high risk for knee osteoarthritis.

MEASUREMENTS

The exposure was leg-length inequality, measured by full-limb radiography. The outcomes were prevalent, incident, and progressive knee osteoarthritis. Radiographic osteoarthritis was defined as Kellgren and Lawrence grade 2 or greater, and symptomatic osteoarthritis was defined as radiographic disease in a consistently painful knee.

RESULTS

Compared with leg-length inequality less than 1 cm, leg-length inequality of 1 cm or more was associated with prevalent radiographic (53% vs. 36%; odds ratio [OR], 1.9 [95% CI, 1.5 to 2.4]) and symptomatic (30% vs. 17%; OR, 2.0 [CI, 1.6 to 2.6]) osteoarthritis in the shorter leg, incident symptomatic osteoarthritis in the shorter leg (15% vs. 9%; OR, 1.7 [CI, 1.2 to 2.4]) and the longer leg (13% vs. 9%; OR, 1.5 [CI, 1.0 to 2.1]), and increased odds of progressive osteoarthritis in the shorter leg (29% vs. 24%; OR, 1.3 [CI, 1.0 to 1.7]).

LIMITATIONS

Duration of follow-up may not be long enough to adequately identify cases of incidence and progression. Measurements of leg length, including radiography, are subject to measurement error, which could result in misclassification.

CONCLUSION

Radiographic leg-length inequality was associated with prevalent, incident symptomatic, and progressive knee osteoarthritis. Leg-length inequality is a potentially modifiable risk factor for knee osteoarthritis.

PRIMARY FUNDING SOURCE

National Institute on Aging.

Symptoms of the knee and hip in individuals with and without limb length inequality

OBJECTIVE

This cross-sectional study examined the association of limb length inequality (LLI) with chronic joint symptoms at the hip and knee in a large, community-based sample, adjusting for the presence of radiographic osteoarthritis (OA) and other confounders.

METHODS

The total study group comprised 3012 participants with complete knee symptoms data, 3007 participants with complete hip symptoms data, and 206 with LLI>or=2 cm. Presence of chronic knee symptoms was defined as report of pain, aching, or stiffness (symptoms) of the knee on most days. Presence of chronic hip symptoms was defined as hip pain, aching, or stiffness on most days or groin pain. Multiple logistic regression models were used to examine the relationship of LLI with knee and hip symptoms, while adjusting for demographic and clinical factors, radiographic knee or hip OA and history of knee or hip problems (joint injury, fracture, surgery, or congenital anomalies).

RESULTS

Participants with LLI were more likely than those without LLI to have knee symptoms (56.8% vs 43.0%, P<0.001), and hip symptoms (49.5% vs 40.0%, P=0.09). In adjusted models, knee symptoms were significantly associated with presence of LLI (adjusted odds ratio [aOR]=1.41, 95% confidence interval, [95% CI] 1.02-1.97), but the relationship between hip symptoms and LLI (aOR=1.20, 95% CI 0.87-1.67) was not statistically significant.

CONCLUSION

LLI was moderately associated with chronic knee symptoms and less strongly associated with hip symptoms. LLI may be a new modifiable risk factor for therapy of people with knee or hip symptoms.

Epidemiology of osteoarthritis

Evolving definitions of osteoarthritis and improvements in risk factor measurement that use advanced imaging, systemic and local biomarkers, and improved methods for measuring symptoms and their impact can help elucidate mechanisms and identify potential areas for intervention or prevention.