Leg Length Discrepancy- Treatment Indications and Strategies

Are artificial intelligence generated lower extremity radiographic measurements accurate in a cohort with implants?

OBJECTIVE

Leg length discrepancy (LLD) and malalignment of the lower extremity can lead to pain and increased risk of osteoarthritis. Radiographic measurements on anteroposterior (AP) full-length radiographs can be used to assess LLD and lower extremity alignment. The primary aim of this study was to evaluate the accuracy of AI software in performing lower extremity radiographic measurements in patients with implants. The secondary aim was to compare its efficiency to that of radiologists.

MATERIALS AND METHODS

This study used the following eight angles and five lengths: hip-knee-angle (HKA), anatomical-tibiofemoral angle (aTFA), anatomical-mechanical-axis angle (AMA), joint-line-convergence angle (JLCA), mechanical-lateral-proximal-femur-angle (mLPFA), mechanical-lateral-distal-femur-angle (mLDFA), mechanical-medial-proximal-tibia-angle (mMPTA), mechanical-lateral-distal-tibia- angle (mLDTA), femur length, tibia length, full leg length, leg-length-discrepancy (LLD), and mechanical-axis-deviation (MAD). Two radiologists and AI software independently performed these measurements on 156 legs. The statistical methods used to assess AI performance were intraclass correlation coefficient (ICC) and Bland-Altman analysis.

RESULTS

The AI generated output for 129/156 legs. 11/13 of the variables showed excellent agreement (ICC ≥ 0.75) between AI and the readers. Bland Altman performance targets were met for 5/13 variables. The mean (standard deviation) reading time for the AI and two readers, respectively, was 38 (6) seconds, 181 (41) seconds, and 214 (77) seconds.

CONCLUSION

In a cohort with lower extremity metal implants, AI-based leg length measurements were fast and accurate although most angular measurements were not.

Aesthetic lower limb lengthening techniques: a systematic review of efficacy, complications, and patient satisfaction

BACKGROUND

Aesthetic limb lengthening (ALL) is a cosmetic procedure aimed at enhancing body symmetry and improving self-esteem through the gradual elongation of bones. Unlike functional limb lengthening, which addresses limb length discrepancies, ALL focuses on increasing limb length for aesthetic purposes. While functional limb lengthening has been extensively studied, a comprehensive analysis of ALL outcomes is needed. This systematic review evaluates the efficacy, complications, and patient satisfaction associated with different ALL techniques, including distraction osteogenesis and various external and internal fixation systems.

METHODS

A systematic search of PubMed, Embase, and Scopus was conducted up to July 2024 to identify relevant studies in English. Eligible studies included case series, cohort studies, and randomized controlled trials with at least 12 months of follow-up. Studies focusing on adult populations undergoing aesthetic limb lengthening were included. Data on limb lengthening achieved, bone healing rates, complications, and patient satisfaction were extracted and synthesized through narrative analysis. The methodological quality of studies was assessed using the MINORS criteria for non-randomized studies.

RESULTS

A total of 12 studies involving 760 patients were included. Most patients were male (67%), with an average age of 24.75 years. Techniques employed included the Ilizarov method, motorized internal lengthening nails (MILN), and combined methods like Lengthening And Then Nailing (LATN). The lengthening achieved ranged from 62 mm to 87 mm, with an average of 67 mm. Patient satisfaction rates ranged from 88.8 to 98%. Psychological outcomes showed improvements in body image and self-esteem. Functionally, most patients resumed normal activities with minimal joint limitations. However, common complications included infections, bone healing issues, joint deformities, and material-related complications.

CONCLUSION

ALL offers high patient satisfaction and psychological benefits, with patients reporting improved body image and self-esteem. Despite these positive outcomes, complications such as infections and bone healing issues remain significant. Further research with rigorous study designs is needed to improve the safety and efficacy of ALL procedures.

Morselized Femoral Head Impaction Bone Grafting of Large Defects in Ankle and Hindfoot Fusions

BACKGROUND

Ankle and hindfoot fusion in the presence of large bony defects represents a challenging problem. The purpose of this study was to evaluate outcomes of patients who underwent ankle-hindfoot fusions with impaction bone grafting (IBG) with morselized femoral head allograft to fill large bony void defects.

METHODS

This was a 3-center, retrospective review of a consecutive series of 49 patients undergoing ankle or hindfoot fusions with femoral head IBG for filling large bony defects. Union was assessed clinically and radiologically with radiography or computed tomography. Graft stability/collapse was identified on radiographs as loss of graft height across the fusion interface. Indications included 35 failed total ankle arthroplasty, talar osteonecrosis and collapse (7 patients), failed ankle fusion (4 patients), trauma with bone loss or fracture nonunion (1 patients), and other (2 patients). Tibiotalocalcaneal (TTC) fusion was performed in 36 (73%) patients and ankle (TT) fusion in 13 (27%).

RESULTS

Mean age was 59.3 (19-78) years. Mean follow-up was 22.9 ± 8.3 months. Eighteen percent were smokers. Mean depth of the bone defect was 35.2 ±8.7 mm, and mean volume of the defect was 62.2 ±5.8 cm3. Symptomatic nonunion rate was 14% (7/49). The mean time to radiologic union was 7.6 ±3.2 months. Complete radiologic union rate occurred in 73% (36/49). Eight TTC fusion patients (22.2%) united at the tibiotalar joint but not at the subtalar joint, of which 6 were asymptomatic. There was no graft collapse, even in patients developing nonunion, with all patients maintaining bone incorporation and leg length.

CONCLUSION

Impaction of morselized femoral head allograft can fill large bony voids around the ankle or hindfoot during fusion, with rapid graft incorporation and no graft collapse despite early loading. This technique offers satisfactory and comparable union outcomes without limb shortening or expensive custom 3D-printed metal cages.

Multicenter survey about leg length discrepancy and total hip arthroplasty: postoperative management

BACKGROUND

We created a Multicenter Survey for Italian orthopedics surgeons on how they approach leg length discrepancy when dealing with primary total hip arthroplasty. Aim of the study was to show how surgeons manage LLD and follow literature recommendations during clinical practice.

METHODS

The Survey was composed of 25 questions divided in 4 sections: surgeon's profile, preoperative and intraoperative evaluation, postoperative management. In this paper, we report the absolute and relative frequencies of answers to section on "postoperative management." Then, regarding the treatment of residual LLD, we reported whether trauma surgeons and experts in replacement surgery had higher odds ratios for providing "literature-based" answers compared to orthopedics physicians.

RESULTS

Only four questions received more than 70% agreement on one of the answers. The OR for giving the "literature-based" answer, taking OP as the reference group was 1.57 for TR and 1.72 for RS for 10 mm LLD at first follow-up (FU) and 1.23 TR and 1.32 RS when 20 mm. When 10 mm LLD at 3 months FU the OR was 0.88 TR and 1.15 RS. The OR for treatment of LLD after the first examination of a new patient was 2.16 TR and 1.85 RS.

CONCLUSIONS

LLD is a debated topic with no definitive recommendations. Many decisions still depend on tradition. Treatment of LLD during clinical practice often differs from literature recommendations.

Hip-related functional limitations in individuals with idiopathic scoliosis: a controlled trial

BACKGROUND

Since scoliosis is a three-dimensional deformity, it causes some movement limitations in the spine and related joints. However, functional limitations associated with scoliosis-related hip joint involvement are the subject of research.

AIMS

This study aims to investigate the physical characteristics and functional limitations associated with idiopathic scoliosis (IS), focusing on hip joint.

METHODS

Demographic characteristics, scoliosis-specific assessments and hip joint active range of motion (RoM), lumbar mobility (Modified Schober test), lumbopelvic stability (Single leg squat test-SLS), hip joint position sense, lower extremity balance (Y-balance test) and lower extremity functionality (Lower extremity functional scale-LEFS) were evaluated.

RESULTS

The study included 120 individuals, with 86 in the scoliosis group (mean age: 15.7 ± 3.4 years) and 34 in the control group (mean age: 16.1 ± 4.8 years). The scoliosis group exhibited limited RoM of the hip joint in flexion, extension, right abduction, adduction, internal rotation, and left external rotation compared to controls (p < 0.001). Lumbar mobility was decreased (p < 0.001). In the joint position sense test, the mean difference for right flexion was and for left flexion. Bilateral decreased SLS test performances (p < 0.001) and Y-balance test performance (p < 0.05) in individuals with IS. LEFS scores were statistically different but not clinically different between groups (p < 0.05).

CONCLUSION

Individuals with IS show decreased hip mobility, lumbopelvic stability, hip joint position sense, and balance compared to healthy peers; however, these limitations do not have a clinical impact on daily living activities.

Intra-rater and Inter-rater Reliability of the KangaTech (KT360) Fixed Frame Dynamometry System During Maximal Isometric Strength Measurements of the Knee Flexors

Background

Fixed-frame dynamometry systems are used worldwide to assess isometric strength in both general and athletic populations. There is currently a paucity of published work where reliability estimates for fixed-frame dynamometry systems have been estimated. The aim of this study was to determine the inter-and intra-rater reliability of the KangaTech (KT360) fixed frame dynamometry system when measuring maximal isometric strength of the knee flexor muscles.

Study Design

Inter and intra-rater reliability single cohort study.

Methods

Twenty healthy university-level athletes (age= 21.65 ± 3 years, weight= 74.465 ± 30kg, height= 170.1 ± 7.0cm) took part in two testing sessions where two raters collected data during a 90° hip and knee flexion protocol. Participants performed each test twice, building to a maximal isometric contraction holding over a 5 second period with 30 second rest between sets. Data were checked for normality using a Shapiro-Wilk test. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) were calculated. Finally, a Bland-Altman analysis was used to determine the levels of agreement for intra-and inter-rater measurements.

Results

High levels of agreement were demonstrated between left and right knee flexion as 95% of the differences were less than two standard deviations away from the mean. 'Almost perfect' intraclass correlation coefficient (ICC) values were demonstrated (Knee flexion: Inter-rater: Left, 0.99; Right, 0.99; Intra-rater: Left, 0.99; Right:0.99). Standard error of measurement (SEM) for inter-and intra-rater strength ranged from 0.26-0.69 kg, SEM% ranged from 1.34-2.71% and minimal detectable change (MDC) ranged from 1.14-2.31kg.

Conclusion

Overall, high level of inter-and intra-rater reliability were demonstrated when testing maximal isometric knee flexion. Therefore, the KT360 fixed frame dynamometry system may be considered a viable tool for measuring maximal isometric contraction of the knee flexors when repeat measures are required in clinical settings.

Level of Evidence

3b.

Periosteal Stripping and Periosteal Division for Leg Length Discrepancy After Proximal Femoral Intertrochanteric Osteotomy for Perthes Disease

Background and objective Periosteal stripping and periosteal division (PSPD) can help promote the growth of the long bone in children with leg length discrepancy (LLD). We performed PSPD in a cohort of patients when LLD was observed at the time of implant removal surgery after proximal femoral osteotomy for Perthes disease. This study aimed to clarify the efficacy and safety of PSPD for acquired LLD related to Perthes disease. Methods This retrospective study enrolled 10 patients treated with PSPD and six controls who declined PSPD for LLD associated with Perthes disease. The lengths of the femur, tibia, and entire leg were measured in the full-length standing radiographs at baseline and final follow-up. The baseline was defined as the time of the last preoperative observation. LLD and changes in LLD (ΔLLD) were measured. The correlation of ΔLLD with age at the time of surgery, follow-up period, and extent of PSPD was investigated. Results In the PSPD group, the mean age of the patients was 9.4 years and the mean LLD at baseline was 20.5 ± 4.6 mm, while it was 10.2 years and 11.5 ± 10.0 mm in the control group. With a mean follow-up period of 4.3 years, the PSPD group showed a mean ΔLLD decrease of 13.9 mm, which was significantly greater than that of the control group at 3.2 mm with a mean follow-up period of 5.4 years. Logistic regression analysis revealed that age at the time of surgery was a significant factor for obtaining >10 mm ΔLLD with PSPD and the cutoff value by the receiver operating characteristic curve was 9.6 years (sensitivity: 0.83; specificity: 0.83). Conclusions PSPD seems to be a safe and effective surgical option for LLD associated with Perthes disease. The age at the time of surgery negatively correlated with the amount of LLD correction. Obtaining >10 mm LLD correction is more likely if the patients are <10 years of age.

Diagnostic performance of deep learning for leg length measurements on radiographs in leg length discrepancy: A systematic review

Purpose

To systematically review the literature regarding machine learning in leg length discrepancy (LLD) and to provide insight into the most relevant manuscripts on this topic in order to highlight the importance and future clinical implications of machine learning in the diagnosis and treatment of LLD.

Methods

A systematic electronic search was conducted using PubMed, OVID/Medline and Cochrane libraries in accordance with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Two observers independently screened the abstracts and titles of potential articles.

Results

A total of six studies were identified in the search. All measurements were calculated using standardized anterior-posterior long-leg radiographs. Five (83.3%) of the studies used measurements of the femoral length, tibial length and leg length to assess LLD, whereas one (16.6%) study used the iliac crest height difference to quantify LLD. The deep learning models showed excellent reliability in predicting all length measurements with intraclass correlation coefficients ranging from 0.98 to 1.0 and mean absolute error (MAE) values ranging from 0.11 to 0.45 cm. Three studies reported measurements of LLD, and the convolutional neural network model showed the lowest MAE of 0.13 cm in predicting LLD.

Conclusions

Machine learning models are effective and efficient in determining LLD. Implementation of these models may reduce cost, improve efficiency and lead to better overall patient outcomes.

Clinical Relevance

This review highlights the potential of deep learning (DL) algorithms for accurate and reliable measurement of lower limb length and leg length discrepancy (LLD) on long-leg radiographs. The reported mean absolute error and intraclass correlation coefficient values indicate that the performance of the DL models was comparable to that of radiologists, suggesting that DL-based assessments could potentially be used to automate the measurement of lower limb length and LLD in clinical practice.

Level of Evidence

Level IV.

Parietal abdominal pain with lower leg discrepancy: a case report

BACKGROUND

This report involves the first publication describing a case of parietal abdominal pain due to lower limb length discrepancy.

CASE PRESENTATION

A Caucasian male patient in his 50s was referred to our rehabilitation department with chronic abdominal pain that began in childhood. This chronic pain was associated with episodes of acute pain that were partially relieved by grade 3 analgesics. The patient was unable to sit for long periods, had recently lost his job, and was unable to participate in recreational activities with his children. Investigations revealed contracture and hypertrophy of the external oblique muscle and an limb length discrepancy of 3.8 cm (1.5 inches) in the left lower limb. The patient was effectively treated with a heel raise, physiotherapy, intramuscular injection of botulinum toxin, and lidocaine. The patient achieved the therapeutic goals of returning to work, and reducing analgesic use.

CONCLUSIONS

Structural misbalances, as may be caused by lower leg discrepancy, may trigger muscular compensations and pain. Complete anamnesis and clinical examination must not be trivialized and may reveal previously ignored information leading to a proper diagnosis.

Hybrid Closed Wedge High Tibial Osteotomy Maintains the Leg Length After Surgery Compared With Open Wedge High Tibial Osteotomy

BACKGROUND

This study aimed to assess the changes in leg length following open wedge high tibial osteotomy (OWHTO) and hybrid closed wedge high tibial osteotomy (h-CWHTO) and whether the change in leg length was associated with preoperative radiographic factors and the change in planned opening or closing width.

METHODS

We retrospectively evaluated the data of patients who underwent OWHTO (n=57) and h-CWHTO (n=31) between 2016 and 2019. Standing full-length anteroposterior radiographs were obtained preoperatively and one year postoperatively. Changes in the lower leg and tibial length were measured using radiography, and the planned opening or closing width was decided via operative planning. Flexion contracture was examined preoperatively and one year postoperatively using a goniometer, and the correlation factors and changes in leg length were analyzed using Spearman's rank correlation.

RESULTS

In the OWHTO group, the lower leg was significantly longer by a mean of 6.0±8.7 mm compared to that preoperatively (p<0.01); however, no significant difference was observed in the h-CWHTO group (mean, -0.56±11.6 mm) (p=0.788). In the OWHTO group, flexion contracture did not improve after surgery, however, in the h-CWHTO group, flexion contracture significantly improved from -7.1±7.0 degrees to -4.7±6.2 degrees postoperatively (p<0.01). No radiographic factors or bone opening or closing width were associated with changes in leg length in both groups.

CONCLUSION

OWHTO led to a significant elongation of the lower leg while leg length was maintained post-h-CWHTO. However, the changes in leg length following both OWHTO and h-CWHTO were not predictable from preoperative radiographic factors or changes in bone width.

Stimulation of skeletal stem cells in the growth plate promotes linear bone growth

Recently, skeletal stem cells were shown to be present in the epiphyseal growth plate (epiphyseal skeletal stem cells, epSSCs), but their function in connection with linear bone growth remains unknown. Here, we explore the possibility that modulating the number of epSSCs can correct differences in leg length. First, we examined regulation of the number and activity of epSSCs by Hedgehog (Hh) signaling. Both systemic activation of Hh pathway with Smoothened agonist (SAG) and genetic activation of Hh pathway by Patched1 (Ptch1) ablation in Pthrp-creER Ptch1fl/fl tdTomato mice promoted proliferation of epSSCs and clonal enlargement. Transient intra-articular administration of SAG also elevated the number of epSSCs. When SAG-containing beads were implanted into the femoral secondary ossification center of 1 leg of rats, this leg was significantly longer 1 month later than the contralateral leg implanted with vehicle-containing beads, an effect that was even more pronounced 2 and 6 months after implantation. We conclude that Hh signaling activates growth plate epSSCs, which effectively leads to increased longitudinal growth of bones. This opens therapeutic possibilities for the treatment of differences in leg length.

An innovative staged prosthetic lengthening reconstruction strategy for osteosarcoma-related leg discrepancy

Correction of leg length discrepancy (LLD) in skeletally mature patients with osteosarcoma was rarely reported and quite challenging. This study aimed to propose a treatment strategy of staged lengthening and reconstruction with a standard static prosthesis to address LLD and restore limb function. It also evaluated the effectiveness of the strategy in terms of leg lengthening, functional outcomes, and complications. The strategy for lengthening included three stages. In stage 1, the previous prosthesis was removed and an external fixator with a temporary rod-cement spacer was placed. In this stage, the external fixator was used to lengthen the limb to the appropriate length. In stage 2, the external fixator was removed and the old rod-cement spacer was replaced with a new one. In stage 3, the rod-cement spacer was removed and the standard static prosthesis was planted. Nine skeletally mature distal femoral osteosarcoma patients with unacceptable LLD were treated in our institution from 2019 to 2021. We performed a chart review on nine patients for the clinical and radiographic assessment of functional outcomes, LLD, and complications. The mean (range) leg lengthening was 7.3 cm (3.6-15.6). The mean (range) LLD of the lower limbs decreased from 7.6 cm (4.1-14.2) before the lengthening to 0.3 cm (- 0.3 to 2.1) at the final follow-up with statistical significance (P = 0.000). The mean (range) Musculoskeletal Tumor Society score improved from 30.3% (16.7%-53.3%) before the lengthening to 96.3% (86.7%-100%) at the final follow-up with statistical significance (P = 0.000). Three patients (33.3%) had a minor complication; none needed additional surgical intervention. In the short term, the current staged lengthening and reconstruction with standard static prosthesis provided satisfactory functional outcomes and LLD correction with few complications. The long-term effects of this method need further exploration.

A systematic approach to managing complications after proximal tibial osteotomies of the knee

Proximal tibial osteotomy (PTO) is an effective procedure for active and young adult patients with symptomatic unicompartmental osteoarthritis and malalignment. They were considered technically demanding and prone to various complications related to the surgical technique, biomechanical or biological origin. Among the most important are hinge fractures and delayed or non-healing, neurovascular complications, loss of correction, implant-related problems, patellofemoral complaints, biological complications and changes in limb length. Being aware of these problems can help minimizing their prevalence and improve the results of the procedure.The aim of this narrative review is to discuss the potential complications that may occur during and after proximal tibial osteotomies, their origin and ways to prevent them.

Clinical outcomes of proximal femoral reconstruction technique combined with THA in the treatment of high dislocation secondary to septic arthritis: a retrospective single-center study

PURPOSE

The aim of this retrospective study was to examine the clinical outcomes and complications of proximal femur reconstruction (PFR) combined with total hip arthroplasty (THA) in patients with high hip dislocation secondary to septic arthritis (SA).

METHODS

Between September 2016 to September 2021, we performed a series of 15 consecutive PFR combined with THA on patients with high dislocation of the hip secondary to SA, of these,12 hips were reviewed retrospectively, with a mean follow-up of 2.5 years (range, 1.5-6 years). The mean age of the patients at the time of surgery was 52 years (range, 40-70 years).

RESULTS

All patients were followed up. At 1-year postoperative follow-up, the median HHS increased from 32.50 preoperatively to 79.50 postoperatively. The median VAS decreased from 7 before surgery to 2 at 1 year after surgery. The median LLD reduced from 45 mm preoperatively to 8 mm at 1 year after surgery. The mean operative time 125 ± 15 min (range 103-195 min). Mean estimated blood loss was500 ± 105ml (range 450-870 ml). Mean hospital days 9.5 days (range 6-15 days). Two patients developed nerve injuries that improved after nutritional nerve treatment. One patient had recurrent postoperative dislocation and underwent reoperation, with no recurrence dislocation during the follow-up. There were no cases of prosthesis loosening during the follow-up period. One patient developed acute postoperative periprosthetic joint infection (PJI) that was treated with Debridement, Antibiotics and Implant Retention (DAIR) plus anti-infective therapy, with no recurrence during 2 years of follow-up.

CONCLUSION

This study indicates PFR combined with THA shows promise as a technique to manage high hip dislocation secondary to SA, improving early outcomes related to pain, function, and limb length discrepancy.

A deep learning method for foot-type classification using plantar pressure images

Background: Flat foot deformity is a prevalent and challenging condition often leading to various clinical complications. Accurate identification of abnormal foot types is essential for appropriate interventions. Method: A dataset consisting of 1573 plantar pressure images from 125 individuals was collected. The performance of the You Only Look Once v5 (YOLO-v5) model, improved YOLO-v5 model, and multi-label classification model was evaluated for foot type identification using the collected images. A new dataset was also collected to verify and compare the models. Results: The multi-label classification algorithm based on ResNet-50 outperformed other algorithms. The improved YOLO-v5 model with Squeeze-and-Excitation (SE), the improved YOLO-v5 model with Convolutional Block Attention Module (CBAM), and the multilabel classification model based on ResNet-50 achieved an accuracy of 0.652, 0.717, and 0.826, respectively, which is significantly higher than those obtained using the ordinary plantar-pressure system and the standard YOLO-v5 model. Conclusion: These results indicate that the proposed DL-based multilabel classification model based on ResNet-50 is superior in flat foot type detection and can be used to evaluate the clinical rehabilitation status of patients with abnormal foot types and various foot pathologies when more data on patients with various diseases are available for training.

[Options and limits of leg length correction in paediatric orthopaedics]

For paediatric orthopaedic surgeons treating leg length discrepancy, knowledge of the available procedures and their options and limits is just as important as mastery of the very different surgical methods and implants, as well as the possible complications, in order to be able to advise and treat the children and adolescents and their parents comprehensively and in the best interests. Both the growth inhibiting procedures and the complex bone lengthening procedures require a great deal of experience to successfully guide patients and families through what is often a lengthy and sometimes complicated treatment process. Careful preoperative indications and planning, precise surgical techniques with suitable instruments and implants, and attentive postoperative check-ups are mandatory prerequisites for the desired therapeutic success.

No significant post-operative limb length difference following medial opening wedge high tibial osteotomy in a multi-ethnic Southeast Asian population

PURPOSE

This study aims to assess the significance of post-operative change in limb length in medial opening wedge high tibial osteotomy (MOWHTO), and evaluate the correlation between correction angles and changes in limb length. We hypothesize that opening wedge height and correction angles directly correlate to changes in limb length.

METHODS

The medical records and radiographs of 91 MOWHTO patients were retrospectively evaluated for relevant radiographical parameters both pre- and post-operatively. The exclusion criteria are: (i) concurrent distal femur osteotomy in the same setting, (ii) other previous unilateral lower limb surgeries prior to MOWHTO and (iii) failure to follow-up with post-operative radiographs. A linear regression model was performed and a line of best fit, Pearson's correlation coefficient (r) and coefficient of determination (R2) were computed. Chi-squared test was also performed, and results with P < 0.05 were considered statistically significant.

RESULTS

There is a statistically significant increase in post-MOWHTO limb length (Absolute Δ = 4.3 ± 2.86 mm, % Δ = 0.652% ± 0.434%, p < 0.001). There was no significant difference in the limb length change between patients with larger (> 8 mm) and smaller (< 8 mm) opening widths. There was a weakly positive correlation between limb length change versus actual (R2 = 0.140, 95%CI [-0.068, 0.336]) and planned correction angles (R2 = 0.196, 95%CI [-0.012, 0.387]).

CONCLUSION

In conclusion, post-MOWHTO change in limb length is statistically significant, but the clinical significance is minimal. Further studies are required to assess other factors. Development of a reliable mathematical model that predicts post-MOWHTO limb length change would be useful in predicting the anatomical outcomes.

LEVEL OF EVIDENCE

Level III. Retrospective Cohort Study.

Simultaneous bilateral versus unilateral total hip arthroplasty: Pain and physical function in a one- and five-year follow-up - retrospective patients record study

BACKGROUND

Total hip arthroplasty (THA) decreases pain and improves function in patients with osteoarthritis. In some cases, both hips have been operated simultaneously. Our aim was to report patients' pain and physical function after one- and five-years post-operatively among patients who underwent unilateral THA and those who underwent bilateral THA at the same time in one orthopaedic hospital in Finland.

METHODS

The study group consisted of 488 patients retrospectively selected patients from a single centre; 421 of them underwent unilateral THA and 67 underwent simultaneous bilateral THA. The patients had two clinical examinations one and five years postoperatively. Systematic data about pain and physical function were collected using the scaled Orton Hip Score (sOHS). Register data on revisions and mortality events were from the Finnish Institute of Health and Welfare.

RESULTS

At the one-year follow-up, total sOHS was improved remarkably from the preoperative situation, both in the unilateral THA (age and gender adjusted mean improvement 42 points (95% CI: 40 to 44, p < 0.001) and in the bilateral THA groups (age and gender adjusted mean improvement 45 [95% CI: 41 to 49], p < 0.001), with no group differences after five-years of operation (age and gender adjusted p = 0.19). Total sOHS was statistically higher in the bilateral THA compared to the unilateral THA after one year (98 vs. 95, p < 0.001) and five years (97 vs. 95, p = 0.003) of operation.

CONCLUSIONS

Patients in unilateral THA and bilateral THA groups had increased their physical function, and pain had decreased after one-year follow-up of the primary THA operation, and condition remained after five years of operation. At follow-ups, patients who underwent bilateral THA had slightly better physical function compared to patients who underwent unilateral THA at follow-up; however, this difference had no clinical relevance.

Automated measurement of leg length discrepancy from infancy to adolescence based on cascaded LLDNet and comprehensive assessment

Background

Deep learning (DL) has been suggested for the automated measurement of leg length discrepancy (LLD) on radiographs, which could free up time for pediatric radiologists to focus on value-adding duties. The purpose of our study was to develop a unified solution using DL for both automated LLD measurements and comprehensive assessments in a large and comprehensive radiographic dataset covering children at all stages, from infancy to adolescence, and with a wide range of diagnoses.

Methods

The bilateral femurs and tibias were segmented by a cascaded convolutional neural network (CNN), referred to as LLDNet. Each LLDNet was conducted through use of residual blocks to learn more abundant features, a residual convolutional block attention module (Res-CBAM) to integrate both spatial and channel attention mechanisms, and an attention gate structure to alleviate the semantic gap. The leg length was calculated by localizing anatomical landmarks and computing the distances between them. A comprehensive assessment based on 9 indices (5 similarity indices and 4 stability indices) and the paired Wilcoxon signed-rank test was undertaken to demonstrate the superiority of the cascaded LLDNet for segmenting pediatric legs through comparison with alternative DL models, including ResUNet, TransUNet, and the single LLDNet. Furthermore, the consistency between the ground truth and the DL-calculated measurements of leg length was also comprehensively evaluated, based on 5 indices and a Bland-Altman analysis. The sensitivity and specificity of LLD >5 mm were also calculated.

Results

A total of 976 children were identified (0-19 years old; male/female 522/454; 520 children between 0 and 2 years, 456 children older than 2 years, 4 children excluded). Experiments demonstrated that the proposed cascaded LLDNet achieved the best pediatric leg segmentation in both similarity indices (0.5-1% increase; P<0.05) and stability indices (13-47% percentage decrease; P<0.05) compared with the alternative DL methods. A high consistency of LLD measurements between DL and the ground truth was also observed using Bland-Altman analysis [Pearson correlation coefficient (PCC) =0.94; mean bias =0.003 cm]. The sensitivity and specificity established for LLD >5 mm were 0.792 and 0.962, respectively, while those for LLD >10 mm were 0.938 and 0.992, respectively.

Conclusions

The cascaded LLDNet was able to achieve promising pediatric leg segmentation and LLD measurement on radiography. A comprehensive assessment in terms of similarity, stability, and measurement consistency is essential in computer-aided LLD measurement of pediatric patients.

Association between preoperative concurrent fibular pseudarthrosis and risk of postoperative ankle valgus in patients with congenital pseudarthrosis of the tibia

BACKGROUND

This study evaluated the correlation of preoperative concurrent fibular pseudarthrosis with the risk of ankle valgus deformity in patients with congenital pseudarthrosis of the tibia (CPT) who underwent successful surgical treatment.

METHOD

The children with CPT who were treated at our institution between 1 January 2013 and 31 December 2020 were retrospectively reviewed. The independent variable was preoperative concurrent fibular pseudarthrosis, and the dependent variable was postoperative ankle valgus. Multivariable logistic regression analysis was performed after adjusting for variables that might affect the risk of ankle valgus. Subgroup analyses with stratified multivariable logistic regression models were used to assess this association.

RESULTS

Of the 319 children who underwent successful surgical treatment, 140 (43.89%) developed ankle valgus deformity. Moreover, 104 (50.24%) of 207 patients with preoperative concurrent fibular pseudarthrosis developed an ankle valgus deformity compared with 36 (32.14%) of 112 patients without preoperative concurrent fibular pseudarthrosis (p=0.002). After adjusting for sex, body mass index, fracture age, age of patient undergoing surgery, surgery method, type 1 neurofibromatosis (NF-1), limb-length discrepancy (LLD), CPT location and fibular cystic change, patients with concurrent fibular pseudarthrosis presented a higher risk of ankle valgus than those without concurrent fibular pseudarthrosis (OR 2.326, 95% CI 1.345 to 4.022). This risk further increased with CPT location at the distal one-third of the tibia (OR 2.195, 95% CI 1.154 to 4.175), age <3 years of patient undergoing surgery (OR 2.485, 95% CI 1.188 to 5.200), LLD <2 cm (OR 2.478, 95% CI 1.225 to 5.015) and occurrence of NF-1 disorder (OR 2.836, 95% CI 1.517 to 5.303).

CONCLUSION

Our results indicate that patients with CPT and preoperative concurrent fibular pseudarthrosis have a significantly increased risk of ankle valgus compared with those without preoperative concurrent fibular pseudarthrosis, particularly in those with CPT location at the distal third, age <3 years at surgery, LLD <2 cm and NF-1 disorder.

Telehealth examination of the lumbar spine

BACKGROUND

Telehealth evaluations of musculoskeletal conditions have increased due to the stay-at-home policies enacted during the COVID-19 pandemic. Back pain is one of the most common complaints in primary care. While telehealth may never supplant in-person evaluation of back pain, it is imperative in a changing world to learn to perform this evaluation via telephone or video. Virtual visits rely on history-taking and patient self-reported descriptions of pain elicited from self-palpation or specific movements while on the telephone with the clinician. Video examinations provide a unique way of evaluating the lower back compared to telephone because of the ability to visualize the actions of the patient.

OBJECTIVE

To create an evaluation pathway for examination of the lumbar spine via telehealth.

METHODS

Our group has created a step-by-step evaluation pathway to help physicians direct their patients through typical lumbar examination elements, including inspection, palpation, range of motion, and strength, special, and functional testing.

RESULTS

We have developed a table of questions and instructions and a glossary of images of each maneuver to facilitate lumbar spine examination via telemedicine.

CONCLUSIONS

This paper provides a guide for extracting clinically relevant information while performing telemedicine examinations of the lumbar spine.

Asymmetry of the pelvis in Polish young adults

Introduction

Symmetry is one of the criteria of correct body posture in upright position. The spatial positioning of the pelvic girdle is crucial to it. Functional and structural asymmetries within the lumbo-pelvic-hip complex can have a significant influence on the structure and functions of many human body organs and systems. The aim of the study was to present the results of inclinometer measurements of selected landmarks of the pelvic girdle in young adults aged 19-29.

Methods

The analysis of occurrence of spatial pelvic asymmetry was based on the authors' original, clinical classification and the significance of the body mass and height for the analyzed asymmetries. The inclinometer measurements of the selected landmarks of the pelvic girdle were performed in a sample consisting of 300 young individuals. Then, the occurrences of the spatial asymmetry of the pelvis were analyzed based on the authors' own clinical classification using alignment symmetry of the iliac crests, the anterior superior iliac spines and the trochanters major as a criterion. All study subjects with asymmetry <1 degree were treated as those with a symmetrical pelvis.

Results

The significance of gender, body mass and height for the analyzed asymmetries was assessed. Symmetric positioning of the iliac crests was observed in only 32% of the respondents. The iliac crest depression on the left side was more frequently observed - in 41% of the respondents. This occurred more often in women (44%) than in men (38%). In the group of women, the rotated pelvis was the most often observed (39.4%) asymmetry, while for men, it was the oblique pelvis (40%). More detailed analysis by pelvic asymmetry subtypes showed their statistical differentiation between women and men (p    <     0.0001). Analysis of moderate rotation of the pelvis for men, were reported slightly higher values but these differences were not statistically significant (p = 0.253). Women, in turn, showed slightly higher mean values but here too, the differences were not statistically significant (p = 0.245).

Discussion

Asymmetries in the pelvis area are common; they were observed in less than three-quarters of the examined population. Oblique pelvis was found in less than a quarter of women and in more than one-third men with the predominant structural asymmetries. Rotated pelvis was observed in more than one-third of women and men with dominating functional asymmetries. There were no linear correlations between the body mass and height, and the angle of asymmetries.

3D printed fracture reduction guides planned and printed at the point of care show high accuracy - a porcine feasibility study

Purpose

After surgical treatment of comminuted diaphyseal femoral and tibial fractures, relevant malalignment, especially rotational errors occur in up to 40–50%. This either results in a poor clinical outcome or requires revision surgery. This study aims to evaluate the accuracy of reduction if surgery is supported by 3D guides planned and printed at the point of care.

Methods

Ten porcine legs underwent computed tomography (CT) and 3D models of femur and tibia were built. Reduction guides were virtually constructed and fitted to the proximal and distal metaphysis. The guides were 3D printed using medically approved resin. Femoral and tibial comminuted diaphyseal fractures were simulated and subsequently reduced using the 3D guides. Postoperative 3D bone models were reconstructed to compare the accuracy to the preoperative planning.

Results

Femoral reduction showed a mean deviation ± SD from the plan of 1.0 mm ± 0.9 mm for length, 0.9° ± 0.7° for varus/valgus, 1.2° ± 0.9° for procurvatum/recurvatum and 2.0° ± 1.7° for rotation. Analysis of the tibial reduction revealed a mean deviation ± SD of 2.4 mm ± 1.6 mm for length, 1.0° ± 0.6° for varus/valgus, 1.3° ± 1.4° for procurvatum/recurvatum and 2.9° ± 2.2° for rotation.

Conclusions

This study shows high accuracy of reduction with 3D guides planned and printed at the point of care. Applied to a clinical setting, this technique has the potential to avoid malreduction and consecutive revision surgery in comminuted diaphyseal fractures.

Level of Evidence

Basic Science.

Preliminary results of two novel devices for epiphysiodesis in the reduction of excessive predicted final height in tall stature

BACKGROUND

In the treatment of tall stature, the reduction of excessive predicted final height can either be achieved by hormonal treatment or surgically by temporary (tED) or permanent (pED) epiphysiodesis. The present study evaluates the preliminary results of two novel devices for tED and pED around the knee to reduce the predicted final height.

MATERIALS AND METHODS

A retrospective analysis was performed to evaluate the clinical and radiographic outcome after bilateral epiphysiodesis for the treatment of tall stature. A cohort of 34 patients (16 girls, 18 boys) who underwent either tED or pED between 2015 and 2020 were eligible for analysis based on the electronic patient records and picture archiving and communication system of our orthopaedic teaching hospital. tED was conducted in 11 patients (32%) through bilateral implantation of four RigidTacks™ (Merete, Berlin, Germany) around the knee. Twenty-three patients (68%) received pED, performed with an EpiStop™ trephine (Eberle, Wurmberg, Germany). The mean overall follow-up time was 2.9 years.

RESULTS

The mean age at surgery was 12.3 years in girls and 13.2 years in boys. Patients had a mean body height of 175.2 cm in girls and 184.7 cm in boys at surgery. The mean predicted final height was 191.4 cm in girls and 210.4 cm in boys. At the last follow-up, 26 patients (76.5%) had achieved skeletal maturity. The mean height of skeletally mature patients was 187.2 cm in girls and 198.5 cm in boys. A mean reduction of the predicted final height of 5.9 cm in girls and 8.7 cm in boys was achieved, corresponding to a reduction in remaining growth of 46% in girls and 38% in boys. Secondary frontal plane deformities of the knee were detected in 5/11 patients (45.5%) in the tED group and 1/23 treatments (4.3%) in the pED group.

CONCLUSIONS

tED and pED have both proven to be efficient at achieving growth inhibition to reduce excessive predicted height. However, tED has been associated with an increased risk of secondary angular deformities of the knee. Furthermore, the risk of implant-related complications and the necessity of a subsequent surgical intervention for implant removal have led our study group to abandon tED when treating tall stature. Long-term results of both procedures are pending.

LEVEL OF EVIDENCE: 4

LIMB-Q Kids—German Translation and Cultural Adaptation

(1) Purpose: Lower limb deformities can have a severe impact on health-related quality of life (HRQL). LIMB-Q Kids is a new patient-reported outcome measure (PROM) aiming to elucidate the experience of 8–18-year-old patients before, during and after treatment, and to measure the different aspects of HRQL. The aim of this study was to translate and culturally adapt LIMB-Q Kids to German. (2) Methods: The International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines were followed. Three forward translations, a backward translation, an expert panel meeting with eight participants, and twenty cognitive debriefing interviews led to the final German version of LIMB-Q Kids. (3) Results: In the forward translations, 4/159 items were difficult to translate, and 2/159 items in the backward translation differed from the original English version. Cognitive debriefing interviews with 20 patients identified 7/159 items that were difficult to comprehend/answer, and 2 of these items were changed. (4) Conclusions: Lower limb deformities can have a great impact on children, and it is important to measure and consider the impact on HRQL. In order to be able to use PROMs in different countries, conceptually equivalent translations and cultural adaptations should be performed in order to ensure comprehensibility. The final German version of LIMB-Q Kids is ready for use in an international field test.

Complication of lengthening and the role of post-operative care, physical and psychological rehabilitation among fibula hemimelia

There is a clear clinical need for efficient physiotherapy and rehabilitation programs during and after bone lengthening and reconstruction for gaining the optimal effect and also prevention or treatment of lengthening side effects. Pin tract infection is the most prevalent side effect during lengthening which could be prevented and treated initially via proper wound care. Muscle contractures are typically a consequence of the generated tension on the distracted muscle. It can be managed by physiotherapy initially and surgically in later severe stages. Furthermore, it is essential to avoid muscle contracture development, which is the demonstration of the imbalanced muscle appeals on the joint to inhibit the following subluxation. The knee is the furthermost affected joint by the aforementioned problem due to the inherent lack of ligamentous and bony stability. Joint stiffness is the other possible unfavorable effect of lengthening. It happens because of extensive muscle contractures or may possibly be attributed to rigidity of the joint following the amplified pressure on the joint surface during the process of lengthening. Physiotherapy and occupational therapy including endurance and strength exercise as well as stretching play an important role during the rehabilitation periods for the prevention and also the treatment of muscle contracture and the following deformity and also joint stiffness. Likewise, the effect of mental and physical rehabilitation programs should not be overlooked.

Biomechanical evaluation and comparison of clinically relevant versus non-relevant leg length inequalities

BACKGROUND

Leg length inequalities are a frequent condition in every population. It is common clinical practice to consider LLIs of 2 cm and more as relevant and to treat those. However, the amount of LLIs that need treatment is not clearly defined in literature and the effect of real LLIs on the musculoskeletal system above and below 2 cm have not been studied biomechanically before.

METHODS

By using surface topography, we evaluated 32 patients (10 females, 22 male) with real LLIs of ≥ 2 cm (mean: 2.72 cm; n = 10) and compared their pelvic position and spinal posture to patients with LLIs < 2 cm (mean: 1.24 cm; n = 22) while standing and walking. All patients were measured with a surface topography system during standing and while walking on a treadmill. To compare patient groups, we used Student t-tests for independent samples.

RESULTS

Pelvic obliquity was significantly higher in patients with LLI ≥ 2 cm during the standing trial (p = 0.045) and during the midstance phase of the longer leg (p = 0.023) while walking. Further measurements did not reveal any significant differences (p = 0.06-0.706).

CONCLUSIONS

The results of our study suggest that relevant LLIs of ≥ 2 cm mostly affect pelvic obliquity and do not lead to significant alterations in the spinal posture during a standing trial. Additionally, we demonstrated that LLIs are better compensated when walking, showing almost no significant differences in pelvic and spinal posture between patients with LLIs smaller and greater than 2 cm. This study shows that LLIs ≥ 2 cm can still be compensated; however, we do not know if the compensation mechanisms may lead to long-term clinical pathologies.

Leg Length Discrepancy and Nonspecific Low Back Pain: 3-D Stereophotogrammetric Quantitative Posture Evaluation Confirms Positive Effects of Customized Heel-Lift Orthotics

Background: The literature reports evidence of leg length discrepancy (LLD) associated with musculoskeletal disorders, alterations in spinopelvic alignment, and body posture, leading to low back pain and lumbar scoliosis. The most common conservative treatment for LLD is the use of internal or external shoe lifts although no treatment guidelines have been established.

Aim: The study aimed to contribute to low back pain–LLD relationship comprehension, highlighting the benefits of LLD correction in the nonspecific low back pain (NSLBP) population.

Methods: A cross-sectional observational study recruited a cohort of 80 NSLBP patients (48 females, 32 males) with LLD, age (μ = 35 ± 17.2). Entire body posture, including 3-D spine shape reconstruction, was measured using a nonionizing 3-D optoelectronic stereophotogrammetric approach. After the first 3-D posture evaluation, patients were provided with customized orthotics, including 100% LLD heel lift correction. No other therapeutic interventions were considered. Pain level was assessed using the numerical pain rating scale (NPRS). The gender, age-related, and time-dependent effects of LLD equalization treatment in NSLBP patients was investigated during 2 years of follow-up. The statistical analysis was performed at the global level using multivariate methods by Hotelling T² tests and intrasubject-level using t-test.

Results and Discussion: An initial average NPRS = 7.8 was determined. In the medium-term follow-up group (4 months), the NPRS dramatically decreased (NPRS = 1.1). The pain disappeared in the long-term (2 years) follow-up group (NPRS = 0). The study results highlight that LLD equalization treatment led to clear statistically significant improvements in all the postural parameters of the frontal plane, including the underfoot load asymmetry. No worsening has been detected. An adaptation period long enough is needed to obtain progressive pain relief improvements and structural posture changes. Younger NSLBP patients showed slightly better improvements than older ones. Minimal differences between healthy young adults’ and NSLBP patients’ postures were found either in natural erect standing posture or when LLD equalization is applied.

Conclusion: Heel-lift customized orthotics with 100% LLD correction are an effective short- and long-term treatment in patients with nonspecific LBP, inducing pain symptom recession and stimulating the improvement of postural parameters without contraindications.

Management of Femur and Tibial Leg Length Discrepancies With a Unilateral External Fixator Is Still Viable When More Advanced Techniques and Hardware Are Unavailable or Cost-Prohibitive

Introduction

Leg length discrepancy (LLD) is an infrequent diagnosis, most commonly occurring congenitally in children and rarely in traumatic incidents in adults. Circumferential external fixators are considered the optimal treatment method, but can be very costly and are not always readily available in less developed nations. The unilateral external fixator predates the circumferential but is more easily available and accessible worldwide and less expensive. This study sought primarily to characterize treatment outcomes using a unilateral external fixator where more advanced forms of treatment for LLD are not available. Secondary objectives included the site of the discrepancy and comparison of etiologies.

Methods

Data were retrospectively reviewed from January 2010 to December 2017 on patients undergoing unilateral external fixation at our institution. Nineteen patients met the criteria, 14 with congenital LLD and five with lower leg bone loss from trauma. Patient demographics (including gender and age), initial presentation, physical examination findings, radiographic findings, and treatment were collected and saved in an electronic medical record.

Results

There were 19 cases of LLD overall, with 14 cases on the tibia and 5 on the femur. Three of the five femur cases occurred in the trauma subgroup. There were 15 cases of congenital LLD and five cases of traumatic LLD. The mean overall LLD was 3.9 cm (2.3-5.2). The mean follow-up until healing for the entire cohort was 10 months (5-22). Patients with congenital LLD were younger than those with traumatic LLD (10.2 years versus 22.5 years, p=0.000013), more likely to have a tibial discrepancy (p=0.034), and had a shorter time frame until full healing (7.6 months versus 19 months, p 0.00001). Patients with a tibial LLD were more likely to have a congenital etiology (p=0.0374) and had a shorter time until full healing compared to patients with a femur LLD (8.5 months versus 14 months, p=0.03541).

Conclusion 

We conclude that bone lengthening utilizing the unilateral external fixator is a good method and is cost-effective for bone lengthening where more advanced techniques are not available or cost-prohibitive. It is simple, and patients and families can collaborate with the surgeon to get a good final result. Patients are generally satisfied and can ambulate well after healing. In a resource-limited environment with cost as a barrier, if used correctly and judiciously, the unilateral external fixator can yield good results.

Distance from the magnification device contributes to differences in lower leg length measured in patients with TSF correction

INTRODUCTION

In absence of deformity or injury of the contralateral leg, the contralateral leg length is used to plan limb lengthening. Length variability on long-leg weight-bearing radiographs (LLR) can lead to inaccurate deformity correction. The aim of the study was to (1) examine the variability of the measured limb length on LLR and (2) to examine the influence of the position of the magnification device.

MATERIALS AND METHODS

The limb lengths of 38 patients during deformity correction with a taylor-spatial-frame were measured retrospectively on 7.3 ± 2.6 (4-13) LLR per patient. The measured length of the untreated limb between LLR were used to determine length variability between LLR in each patient. To answer the secondary aim, we took LLR from a 90 cm validation distance. A magnification device was placed in different positions: at the middle of the 90 cm distance (z-position), 5 cm anterior and 5 cm posterior from the z-position, at the bottom and top of the validation distance as well as 5 cm medial and 15 cm lateral from the z-position.

RESULTS

The measured length variability ranged within a patient from 10 to 50 mm. 76% of patients had a measured limb length difference of ≥ 2 cm between taken LLR. Compared to length measurement of the 90 cm test object with the magnification device in the z-position (90.1 cm), positioning the device 5 cm anterior led to smaller (88.6 cm) and 5 cm posterior led to larger measurements (91.7 cm). The measured length with the magnification device at the bottom, top, medial or lateral (90.4; 89.9; 90.2; 89.8 cm) to the object differed not relevantly.

CONCLUSIONS

High variability of limb length between different LLR within one patient was observed. This can result from different positions of the magnification device in the sagittal plane. These small changes in positioning the device should be avoided to achieve accurate deformity correction and bone lengthening. This should be considered for all length and size measurements on radiographs.

Leg length discrepancy: A systematic review on the validity and reliability of clinical assessments and imaging diagnostics used in clinical practice

BACKGROUND

A variety of assessments to determine leg length discrepancy (LLD) is used in clinical practice and evidence about validity and reliability may differ.

OBJECTIVE

The objective of this systematic review was to identify and describe the validity and reliability of different assessments and imaging diagnostics for the determination of LLD.

MATERIALS AND METHODS

The review was conducted following the recommendations of Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). The databases Medline (PubMed) and Index to Chiropractic Literature were systematically searched. Studies regarding clinical assessments and imaging diagnostics for the diagnosis of LLD, which reported the clinimetric properties for assessment of LLD, were included and screened for methodological quality using the Quality Assessment of Studies of Diagnostic Accuracy (QUADAS-2) tool for validity studies and the Quality Appraisal of Diagnostic Reliability (QAREL) tool for reliability studies.

RESULTS

Thirty-seven articles on clinical assessments and 15 studies on imaging diagnostics met the eligibility criteria. Thirteen studies on the validity of clinical assessments and six studies on the validity of imaging diagnostics had a low risk of bias and low concerns regarding applicability for all domains. One study on the reliability of clinical assessments and one study on the reliability of imaging diagnostics had a low risk of bias. Main limitations were, that an analysis of sensitivity and specificity was only performed in a few studies and that a valid reference standard was lacking in numerous studies on clinical assessments.

CONCLUSIONS

For the clinical assessment of LLD, the block test appears to be the most useful method. Full-length standing anteroposterior radiography seems to be the most valid and reliable method and may be used as global reference standard to measure the anatomic LLD when comparing clinical methods and imaging diagnostics.

Enhancing the Efficiency of Distraction Osteogenesis through Rate-Varying Distraction: A Computational Study

Distraction osteogenesis (DO) is a mechanobiological process of producing new bone and overlying soft tissues through the gradual and controlled distraction of surgically separated bone segments. The process of bone regeneration during DO is largely affected by distraction parameters. In the present study, a distraction strategy with varying distraction rates (i.e., "rate-varying distraction") is proposed, with the aim of shortening the distraction time and improving the efficiency of DO. We hypothesized that faster and better healing can be achieved with rate-varying distractions, as compared with constant-rate distractions. A computational model incorporating the viscoelastic behaviors of the callus tissues and the mechano-regulatory tissue differentiation laws was developed and validated to predict the bone regeneration process during DO. The effect of rate-varying distraction on the healing outcomes (bony bridging time and bone formation) was examined. Compared to the constant low-rate distraction, a low-to-high rate-varying distraction provided a favorable mechanical environment for angiogenesis and bone tissue differentiation, throughout the distraction and consolidation phase, leading to an improved healing outcome with a shortened healing time. These results suggest that a rate-varying clinical strategy could reduce the overall treatment time of DO and decrease the risk of complications related to the external fixator.

Focal osteolysis and corrosion at the junction of Precice Stryde intramedullary lengthening device : preliminary clinical, radiological, and metallurgic analysis of 57 lengthened segments

Aims

This study aims to enhance understanding of clinical and radiological consequences and involved mechanisms that led to corrosion of the Precice Stryde (Stryde) intramedullary lengthening nail in the post market surveillance era of the device. Between 2018 and 2021 more than 2,000 Stryde nails have been implanted worldwide. However, the outcome of treatment with the Stryde system is insufficiently reported.

Methods

This is a retrospective single-centre study analyzing outcome of 57 consecutive lengthening procedures performed with the Stryde nail at the authors’ institution from February 2019 until November 2020. Macro- and microscopic metallographic analysis of four retrieved nails was conducted. To investigate observed corrosion at telescoping junction, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) were performed.

Results

Adjacent to the nail’s telescoping junction, osteolytic changes were observed in bi-planar radiographs of 20/57 segments (35%) after a mean of 9.5 months (95% confidence interval 7.2 to 11.9) after surgery. A total of 8/20 patients with osseous alterations (40%) reported rest and ambulation pain of the lengthened segment during consolidation.

So far, 24 Stryde nails were retrieved and in 20 (83%) macroscopic corrosion was observed at the nail’s telescoping junction. Before implant removal 11/20 radiographs (55%) of lengthened segments with these 20 nails revealed osteolysis. Implant retrieval analysis by means of SEM showed pitting and crevice corrosion. EDX detected chromium as the main metallic element of corrosion.

Conclusion

Patients are exposed to the risk of implant-related osteolysis of unclear short- and long-term clinical consequences. The authors advocate in favour of an early implant removal after osseous consolidation.

Cite this article: Bone Joint Res 2021;10(7):425–436.

Staged reconstruction of unilateral neglected hip dislocation through total hip arthroplasty and subsequent intramedullary femoral lengthening

Background and purpose

Total hip arthroplasty (THA) is a successful approach to treat unilateral symptomatic neglected hip dislocation (NHD). However, the extensive leg length discrepancy (LLD) can hereby only be partially corrected. In case of residual LLD of more than 2 cm, subsequent femoral lengthening can be considered.

Patients/material/methods

Retrospective analysis of clinical data and radiographs of five patients (age 38.1 (28–51) years) with unilateral NHD who underwent THA with (n  = 3) or without (n = 2) subtrochanteric shortening osteotomy (SSO) and secondary intramedullary femoral lengthening through a retrograde magnetically-driven lengthening nail (follow-up 18.4 (15–27) months).

Results

LLD was 51.0 (45–60) mm before and 37.0 (30–45) mm after THA. Delayed bone union at one SSO site healed after revision with autologous bone grafting and plate fixation. Subsequent lengthening led to leg length equalisation in all patients. Complete consolidation was documented in all lengthened segments.

Conclusion

Staged reconstruction via THA and secondary femoral lengthening can successfully be used to reconstruct the hip joint and equalise LLD. The specific anatomical conditions have to be taken into consideration when planning treatment, and patients ought to be closely monitored.

Mid-Term Outcomes of Cementless Total Hip Arthroplasty in Adult Patients with Childhood Hip Infection

BACKGROUND Patients with hip joint infections in childhood often have many aftereffects of different degrees, regardless of the kind of treatment or natural course. Total hip arthroplasty is currently the most effective treatment for sequelae of childhood hip septic or tuberculous infection. This is a mid-term follow-up study of treatment results of patients who had undergone total hip arthroplasty (THA) with cementless prostheses. MATERIAL AND METHODS We retrospectively analyzed and followed 45 patients (45 hips) who underwent THA with cementless prostheses between 2010 and 2017. There were 45 patients, including 17 men and 28 women. The average age of the patients was 46 years (range, 18-67 years). All hip infections occurred in early childhood or adolescence, and the mean interval between initial infection and THA was 38.2 years (range, 15-60 years). The mean follow-up was 6.1 years (range, 2.7-9.5 years). RESULTS Two patients underwent revision surgery because of loosening of the prosthesis, and 1 patient underwent revision surgery because of a new infection with no relationship with childhood infection during the follow-up. The average Harris hip scores significantly increased from 43.1 to 86.4 (P<0.01), and the average visual analog scale significantly increased from 4.6 to 1.7 (P<0.01). The hip dysfunction and osteoarthritis outcome scores were also significantly changed (P<0.01) at the final follow-up. There were 2 cases of transient sciatic nerve palsy and intraoperative periprosthetic fractures in 3 cases. During follow-up, single revision was performed after 6 years of primary arthroplasty because of aseptic loosening in 2 cases and prosthesis infection in 1 case, which was not related to childhood pathogens. CONCLUSIONS THA for patients with sequelae of hip joint infection has a satisfactory effect that can effectively relieve joint pain and improve hip function. The recurrence rate of infection after either pyogenic infection or tuberculous is very low. The mid-term outcomes of THA in this setting were satisfactory, with high prosthesis survivorship and hip function scores.