Anterior Percutaneous Hemiepiphysiodesis of the Distal Aspect of the Femur: A New Technique: A Case Report

Anterior distal femoral hemiepiphysiodesis for knee flexion contracture in paediatric patients with neuromuscular disorders: A systematic review and meta- analysis

BACKGROUND

This meta-analysis assesses the effectiveness of ADFH in the operative management of knee flexion contracture in children with neuromuscular disorders.

METHODS

The study included 218 patients and assessed 340 knees. Patients had a median age of 11 years (age range 4-17 years) at initial evaluation. The mean follow up time was 25 months.

RESULTS

Gait deviation index improved by 8.49 points following ADFH (95 % CI 4.82-12.15, p < 0.01). Minimum flexion angle saw an overall improvement of 20.61 degrees (95 % CI 15.8 - 26.04, p < 0.001). Knee flexion contracture had an overall improvement of 11.74 degrees across (95 % CI 10.14-13.33, p < 0.001). Popliteal angle improved by 15.59 degrees overall following ADFH (95 % CI 7.57-23.60), p < 0.01).

CONCLUSION

Orthopaedic operations are known to improve knee kinematics and clinical examination findings in neuromuscular disorder patients. ADFH is effective in improving passive and dynamic sagittal knee function.

Knee surveillance for ambulant children with cerebral palsy

Purpose

A majority of ambulant children with cerebral palsy (CP) develop progressive musculoskeletal pathology (MSP) during growth. Fixed flexion deformity at the knee joint (FFDKn) contributes to flexed knee gait and is prone to relapse after index multi-level surgery. This perspective introduces the concept of "knee surveillance" (KS), defined as a repeated systematic assessment of gait and knee range of motion until skeletal maturity. KS aims to detect early FFDKn, allowing for early intervention with minimally invasive techniques such as anterior distal femur hemiepiphysiodesis (ADFH), and reduce the need for higher-risk surgery such as distal femoral extension osteotomy (DFEO) and patellar tendon shortening (PTS).

Methods

Recent literature on the assessment of ambulant children with CP, consensus statements on indications for dose-based knee surgery, and the indications for ADFH have been reviewed and synthesized. These provide a preliminary evidence base for the concept of KS in ambulant children with CP.

Conclusion

We propose the concept of KS for ambulant children with CP. The goals of KS are early detection of knee flexion deformity, early intervention, less invasive surgery, and better long-term outcomes. There is preliminary evidence to suggest that soft-tissue surgery, in combination with ADFH, can reduce, or perhaps replace, the need for more invasive surgery such as DFEO and PTS.

Level of evidence

IV.

Posterior Proximal Tibial Hemiepiphysiodesis: A Report of Two Cases

CASE

Apex posterior or recurvatum deformity of the proximal tibia is an uncommon skeletal alignment. Guided growth, or hemiepiphysiodesis, is a well-established technique for correcting periarticular deformities of the knee in children. A novel technique of posterior proximal tibial hemiepiphysiodesis (PPTHE), performed though a posterior approach, is described in combination with physeal bar resection for correction of post-traumatic proximal tibial recurvatum. Two cases are reviewed including surgical technique with 21-month and 30-month outcomes.

CONCLUSION

Proximal tibial recurvatum in children can be corrected with posterior proximal tibial hemiepiphysiodesis. The procedure may be combined with physeal bar resection in cases of post-traumatic deformity.

Anterior Distal Femoral Hemiepiphysiodesis Using Coronally Oriented 8-plates for the Correction of Fixed Knee Flexion Deformities in Children-Preliminary Results

INTRODUCTION

The original technique for guided growth of the distal femur for correction of pediatric fixed knee flexion deformities (FKFDs) involves the utilization of two 8-plates inserted on either side of the trochlear groove, a technique that has been frequently linked to the development of persistent postoperative knee pain and crepitus. The present study aimed to assess the preliminary results of a novel technique where the two 8-plates are fixed in the coronal plane, one on each of the medial and lateral surfaces, so that they occupy the anterior part of the distal femur.

METHODS

Our study was a prospective case series that included cases with FKFD of >10 degrees in children with at least 12 months of predicted growth remaining. The preoperative knee flexion contracture angle was documented. The surgical procedure entailed the insertion of 2 coronally oriented 8-plates on the medial and lateral surfaces of the distal femur as anterior as possible to the axis of the femur without encroachment on the trochlear groove. The duration of time required to attain full knee extension and any complications encountered were recorded. Wilcoxon signed-rank was used to compare the preoperative and final contracture angles. The level of statistical significance was set at P <0.05.

RESULTS

Thirteen knees in 8 patients (6 boys and 2 girls) were included. The median age was 11 years (6 to 14). There was a significant improvement in the FKFD for the whole cohort from 25 degrees (14 to 42) to 0 degrees (-9 to 8), P <0.05. The median rate of correction was 2.0 degrees/month (0.9 to 5.8). The time till full correction was 14 months (4 to 25). Postoperative knee pain and metalware-related complications were not reported by any patient during follow-up.

CONCLUSIONS

Guided growth of the distal femur using coronally oriented 8-plates is an effective procedure for the treatment of FKFDs in children. This modified technique may achieve faster correction while minimizing the risk of postoperative knee pain compared with the conventional technique.

LEVEL OF EVIDENCE

Level IV-case series.

Anterior Proximal Tibial Screw Hemiepiphysiodesis Decreases Posterior Tibial Slope in Knee Flexion Contracture: A Case Report

CASE

A 13-year-old adolescent boy with hemiplegic cerebral palsy suffering from fixed knee flexion deformity of 10° despite extensive conservative treatment. Owing to a posterior tibial slope (PTS) of 16°, anterior hemiepiphysiodesis was applied to the proximal tibia. The 2 screws were removed after 9 months. Final follow-up at 16 months showed complete knee extension and a PTS of 4°.

CONCLUSION

The presented technique is a good alternative in knee flexion deformity with an increased PTS and has surprisingly not been described in the literature. This might be worth considering for other pathologies such as pediatric anterior cruciate ligament injury with an increased PTS.

Anterior Distal Femoral Hemiepiphysiodesis in Children With Fixed Knee Flexion Deformities: Does Screw Position Matter?

BACKGROUND

Anterior distal femoral hemiepiphysiodesis (ADFH) using 2 percutaneous screws is an effective technique for the treatment of fixed knee flexion deformities in children with neuromuscular disorders. The role of sagittal screw position on the outcome of the procedure is unknown.

METHODS

This is a retrospective case series of patients who underwent ADFH at a single pediatric hospital from 2013 to 2020. Radiographs were evaluated for sagittal screw position and the associated change in lateral distal femoral physeal angle over time. The position of the 2 screws was classified as either being both in the anterior third of the physis (AA), one screw in the anterior third and the other screw in the middle third (AM), or both screws in the middle third of the physis (MM).

RESULTS

The study population included 68 knees in 36 patients. The mean physeal angle at the time of surgery was 93 degrees (SD 4.0 degrees), which increased to 102.4 degrees (SD 5.7 degrees) at 12 months, for a change of 9.4 degrees ( P <0.001). At 24 months, the mean physeal angle was 104.6 degrees (SD 6.3 degrees) for a further change of 2.9 degrees ( P <0.001). When stratified by screw position all screw configurations resulted in an increase in the physeal angle at 12 months. At the 24-month follow-up, the physeal angle in knees with AA screws continued to increase another 3.5 degrees ( P <0.05), there was a minimal change in knees with AM screws (1.47°, P >0.05) and knees with MM screws saw a reversal of physeal angle change (-7.1 degrees, P <0.05).

CONCLUSIONS

ADFH using percutaneous screws results in an increase in the lateral distal femoral physeal angle. The rate of correction is largest in the first 12 months after the procedure. As such, this procedure should be considered in patients with less than 2 years of growth remaining. However, initial screw positioning influences the amount of change over time, and close postoperative surveillance until physeal closure is essential for all patients.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Nonmetallic Anterior Hemiepiphysiodesis of the Distal Femur with a Low-Profile, Pretensioned Implant: A Case Report

CASE

A 14-year-old adolescent boy with left-sided spastic hemiplegic cerebral palsy presented with a 14° left knee flexion contracture and resultant gait disturbance in the setting of an open distal femoral physis. He underwent subsequent anterior distal femur hemiepiphysiodesis with a suture anchor-based, nonmetallic implant. He achieved full correction at the 1-year follow-up and underwent uncomplicated implant removal.

CONCLUSION

A low-profile, suture-based implant used for pediatric knee flexion deformity may allow surgeons to control growth in a reversible fashion by tensioning the physis while possibly avoiding some of the complications associated with currently used implants.

Distal Femur Anterior Hemiepiphysiodesis for Fixed Knee Flexion Deformity in Neuromuscular Patients: A Systematic Review

BACKGROUND

In the past decade, distal femur anterior hemiepiphysiodesis for fixed knee flexion deformity has gained popularity. In this study, we aim to systematically review the literature on this technique as a treatment for fixed knee flexion deformity in patients with neuromuscular disorders.

METHODS

A systematic review was performed in the following databases: PubMed, Embase, and Medline. The inclusion criteria included anterior hemiepiphysiodesis of the distal femur for patients with neuromuscular disorders and fixed knee flexion deformities.

RESULTS

Our search yielded 419 titles. A total of 12 articles were qualified for final review based on the inclusion and exclusion criteria. The total number of patients was 279, with 483 knees corrected. The male to female ratio was 2.1:1, and the mean age of the patients was 11.3 ± 1.4 years (range 4-17 years). The mean preoperative flexion deformity was 23.1° ± 10.0° (range 10°-90°). The mean residual flexion deformity at the final follow-up was 8.6° ± 9.0° (range 0°-32.5°), which corresponds to a statistically significant decrease compared with the preoperative deformity (p < 0.05).

CONCLUSION

Anterior hemiepiphysiodesis for fixed knee flexion deformity provides favourable outcomes with low complication rates in patients with neuromuscular disorders. Future studies should focus on comparing the long-term outcomes of the different metal implants used for these operations.

LEVEL OF EVIDENCE

Level III. See Instructions for Authors for a complete description of levels of evidence.

Mechanics of guided growth of the distal femur for correction of fixed knee flexion deformities: an extra-articular technique

INTRODUCTION

Anterior distal femoral hemiepiphysiodesis using intra-articular plates for correction of pediatric fixed knee flexion deformities (FKFD) has two documented complications: postoperative knee pain and implant loosening. The aim of this study is to investigate the mechanical properties of a novel extra-articular technique for anterior distal femoral hemiepiphysiodesis in patients with FKFD and to compare them to the conventional technique.

MATERIALS AND METHODS

Sixteen femoral sawbones were osteotomized at the level of the distal femoral physis and fixed by rail frames to allow linear distraction simulating longitudinal growth. Each sawbone was tested twice: first using the conventional technique with eight plates placed anteriorly just medial and lateral to the femoral sulcus (group A) and then with plates inserted in the proposed novel location at the most anterior part of the medial and lateral surfaces of the femoral condyles with screws in the coronal plane (group B). Gradual linear distraction was performed, and the resulting angular correction was measured. Strain gauges were attached to the plates, and the amount of strain (and equivalent stress) over the plates in response to linear distraction was recorded. The two groups were compared using the Wilcoxon signed-rank test.

RESULTS

The amount of angular correction was statistically higher in group B (extra-articular plates) at 5, 10-, and 15-mm of distraction (p < 0.001). As regards stress over the plates, the maximum stress and the area under the curve (sum of all stresses measured throughout the distraction process) were significantly higher when the plates were inserted at the conventional position (group A) (p < 0.001).

CONCLUSIONS

During anterior distal femoral hemiepiphysiodesis, the fixation of the eight plates in the coronal plane at the anterior part of the femoral condyles may produce a greater amount of correction and a lower degree of stress over the implants as compared to the conventional technique.

Screw Anterior Distal Femoral Hemiepiphysiodesis in Children With Cerebral Palsy and Knee Flexion Contractures: A Retrospective Case-control Study

BACKGROUND

In children with cerebral palsy who demonstrate hamstring tightness, increasing attention is being paid to less invasive methods of correcting knee flexion contractures. Guided growth principles represent one such approach, and in tandem with a serial extension casting protocol, may provide a less invasive method of addressing these contractures. To date, no evidence is available on this combination of procedures. The purpose of this study was to investigate the effectiveness of a combined lengthening/guided growth procedure (hamstring lengthening, percutaneous anterior screw hemiepiphysiodesis, and serial extension casting) in addressing knee flexion contracture, and to compare this approach to hamstring lengthening and serial extension casting alone.

METHODS

Measures from preoperative and postoperative gait analyses were reviewed retrospectively for 10 patients with cerebral palsy who underwent anterior screw hemiepiphysiodesis and hamstring lengthening followed by serial extension casting [anterior epiphysiodesis (AE) group]. These findings were compared with measures from 19 patients with cerebral palsy who underwent hamstring lengthening followed by serial extension casting [no anterior epiphysiodesis (NAE) group]. Postoperative changes in clinical, functional, and kinematic parameters were assessed. Radiographic parameters were also assessed for the AE group.

RESULTS

In the AE group, improvements were measured in knee contracture, popliteal angle, peak stance phase knee extension, knee range of motion, and Gait Deviation Index. Similar results were observed in the NAE group. In the AE group, the lateral distal femoral angle increased into extension by 20.9 degrees at an average of 26-month follow-up. Both groups showed an increase in pelvic tilt postoperatively. There were no surgical complications associated with the screw anterior hemiepiphysiodesis. Four patients did have complaints of knee pain, but the pain was attributable to the implants in only one patient.

DISCUSSION

The AE group demonstrated statistically greater postoperative improvement in popliteal angle, knee flexion contracture, and peak knee extension during stance than the NAE group. Both procedures led to improvements in clinical and functional measures, indicating the validity of this approach as a means of correcting flexion contracture that is less invasive and allows immediate weight bearing.

LEVEL OF EVIDENCE

Level III-therapeutic study.

Anterior distal femoral hemiepiphysiodesis with and without patellar tendon shortening for fixed knee flexion contractures in children with cerebral palsy

PURPOSE

Surgery is often required for fixed knee flexion contractures in patients with neuromuscular conditions. Anterior distal femoral hemiepiphysiodesis (ADFH) is an alternative to distal femoral extension osteotomy (DFEO) in skeletally immature patients. ADFH is typically not accompanied by patellar tendon shortening surgery (PTS). Our purpose was to compare ADFH alone versus ADFH with PTS for treatment of fixed knee flexion contractures and crouched gait in children with cerebral palsy (CP).

METHODS

Retrospective review of pre- and postoperative gait analysis data for children with CP who underwent ADFH alone, or ADFH with PTS. Data were analysed using linear mixed models to control for covariates.

RESULTS

In total, 25 participants (42 limbs) were included, 17 male and eight female, mean age at surgery 12.9 (sd 1.9) years. Both groups experienced significant improvement in popliteal angle, knee extension range of motion (ROM) and knee extension in stance phase. Greater improvement was seen for all variables in the ADFH/PTS group, mainly due to greater popliteal angle and knee flexion during gait preoperatively in that group (p ≤ 0.02) rather than the procedure performed (p ≥ 0.19). There was no difference between groups postoperatively. Rate of contracture resolution was 0.5° to 1.0° per month, faster in larger contractures (p = 0.02).

CONCLUSIONS

ADFH with and without PTS is effective in improving knee extension in skeletally immature patients with CP, correcting contractures at a rate of 0.5° to 1.0° per month. Combined ADFH and PTS surgery may be preferable in patients with larger contractures of up to 30° to 35°.

LEVEL OF EVIDENCE

III.

Orthopaedic management of knee joint impairment in cerebral palsy: A systematic review and meta-analysis

BACKGROUND

The optimal management of impaired knee joint function in patients with cerebral palsy (CP) remains a significant and ongoing challenge in paediatric orthopaedic surgery.

RESEARCH QUESTION

What are the clinical and functional outcomes after operative and non-operative orthopaedic interventions for knee joint impairment in patients with CP?

METHODS

This systematic review and meta-analysis of orthopaedic interventions for the management of knee joint impairment in paediatric CP patients evaluated study-level data in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. We performed searches of the following electronic databases from their dates of inception to November 2019: Medline (Ovid), Embase (Ovid) and Pubmed. We extracted mean differences in pre-operative and post-operative measurements for the following outcomes: minimum knee flexion in stance; knee flexion at initial contact; maximum knee flexion in swing; range of motion; popliteal angle; fixed flexion deformity angle; and mean pelvic tilt.

RESULTS

Sixty-nine retrospective cohort studies, prospective cohort studies and RCTs comprising 2991 patients were included with 4578 knees analysed. Included studies were of sufficient quality as assessed by the MOOSE checklist. Operative interventions showed significant improvement in knee flexion at initial contact, knee flexion in stance, range of motion, popliteal angle and fixed flexion deformity which were comparable when subgrouped according to operative technique. In contrast, non-operative techniques and botulinum toxin injection did not confer significant improvements. Operative interventions for knee joint impairment led to increased mean pelvic tilt and reduced maximum knee flexion in swing.

SIGNIFICANCE

This review provides strong evidence that operative interventions for the management of knee joint impairment in cerebral palsy patients improve knee kinematics and clinical examination findings.

Update on guided growth concepts around the knee in children

Guided growth is part of the surgical armamentarium for limb-length discrepancy or axial deformity. It is an old concept, with several apparently conflicting techniques that are in fact usually complementary. Depending on whether the aim is to slow or arrest growth, to treat length discrepancy or axial deviation, techniques differ and the choice is partly determined by the indication. It is thus essential to know the technical details for each: temporary or definitive, complete or asymmetric, with or without implant. Considerations of fashion and personal habits may outweigh basic principles, and it is important to go back to the princeps descriptions: the Phemister, Bowen, Blount, Métaizeau and Stevens techniques and others all have their surgical specificities Apart from surgery itself, he indication and choice of technique depend on the patient's age and whether the abnormality to be treated is isolated or part of a wider syndrome, all of this being included in a precise strategy based on planning calculations that are indispensable ahead of any surgery. Guided growth can also be implemented elsewhere than in the limbs: wrist, ankle, or even hip; and it is beginning to be possible to correct sagittal and rotational deformities. All of this is furthermore achievable using emerging techniques that are less invasive, are reversible, and show equal efficacy.

Comparison of plate and screw constructs versus screws only for anterior distal femoral hemiepiphysiodesis in children

The study aim was to compare methods of anterior distal femoral hemiepiphysiodesis (ADFH) for treatment of fixed knee flexion deformities in ambulatory children with neuromuscular conditions and flexed knee gait. This is a retrospective review of 47 children (14 female, 33 male, age at surgery: 12.1 ± 2.7 years) who underwent ADFH between 2009 and 2016. Subjects were grouped by ADFH construct: one transphyseal screw (N = 11), two transphyseal screws (N = 28) or plates and screws (P/S group, N = 8). Clinical/radiographic variables were analyzed using paired t tests, χ tests, multiple regression and analysis of covariance. Participants experienced significant reduction in knee flexion contractures (Δ12°, P < 0.006), with no difference among groups (P = 0.43). Postoperative knee pain was significantly more prevalent in the P/S group (5/8, 63%) than the 1-SCR group (0/11, 0%) and the 2-SCR group (2/28, 7%) (P = 0.002). ADFH results in significant reduction of knee flexion deformity and improved knee extension during gait. Plate and screw constructs, the 1 and 2 transphyseal screw techniques are equally effective, but plate and screw constructs may be associated with a higher risk of persistent postoperative knee pain.

MRI safety and imaging artifacts evaluated for a cannulated screw used for guided growth surgery

OBJECTIVE

Percutaneously-placed cannulated screws are the implant of choice for treatment of skeletal deformity associated with growing children that have spastic cerebral palsy (CP). These patients often require MRI examinations throughout their childhood to evaluate associated comorbidities and frequently for research protocols. There are concerns related to the use of MRI when metallic implants are present. Therefore, this study characterized MRI safety and imaging artifacts for a cannulated screw commonly used for guided growth.

METHODS

Standardized and well-accepted in vitro techniques were used to evaluate a cannulated screw (4.5 mm diameter x 50 mm length, 316 L stainless steel) for MRI issues. Static magnetic field interactions (i.e., translational attraction and torque) and artifacts were tested at 3-Tesla. Radiofrequency-related heating was assessed at 1.5-Tesla/64-MHz and 3-Tesla/128-MHz using relatively high levels of RF energy (whole-body averaged specific absorption rates of 2.7 W/kg and 2.9-W/kg, respectively). Artifacts were determined using T1-weighted, spin echo and gradient echo pulse sequences.

RESULTS

The cannulated screw exhibited minor magnetic field interactions (14° deflection angle, no torque). The highest temperature changes at 1.5-Tesla/64-MHz and 3-Tesla/128-MHz MRI were 2.1 °C and 2.4 °C, respectively. The maximum artifact size on a gradient echo sequence extended 20 mm relative to the dimensions of the implant.

CONCLUSIONS

The in vitro tests performed on the cannulated screw indicated that there were no substantial concerns with respect to the use of 1.5- and 3-Tesla MRI. Therefore, a patient with this cannulated screw can safely undergo MRI by following specific conditions to ensure safety.

Anterior Guided Growth of the Distal Femur for Knee Flexion Contracture: Clinical, Radiographic, and Motion Analysis Results

BACKGROUND

Fixed knee flexion deformity is common in children with neuromuscular disorders. Anterior guided growth (AGG) of the distal femur can achieve gradual correction in patients who are skeletally immature. Little outcome data are available on this procedure.

METHODS

This is a retrospective matched cohort study. Forty-two knees (26 patients) underwent AGG surgery at our institution between 2007 and 2017. All patients underwent instrumented 3-dimensional gait analysis (3DGA). A nonsurgical control group of 49 knees (43 patients) was selected that matched for age, severity of preoperative knee contracture, and 3DGA parameters. Clinical, radiographic, and 3DGA outcomes were assessed and compared.

RESULTS

Average preoperative knee flexion deformity in AGG group was 13±8 degrees. Following AGG, deformity improved by 8±7 degrees (P<0.001) as measured radiographically and by 7±7 degrees (P<0.001) as measured on physical examination. Average rate of correction was 0.7±0.6 degrees per month or 8±8 degrees per year. The 3DGA parameters such as minimum stance phase knee flexion and knee flexion at initial contact were also significantly improved following AGG. In contrast, flexion deformity as measured radiographically worsened by 3±3 degrees (P=0.002) in the control group. Twelve knees (29%) had failure of correction. Predictors of failure included older age, lower level of function, and greater severity of preoperative deformity. The age at time of surgery and the anteroposterior position of plate fixation relative to the distal femoral physis were associated with rate of correction.

CONCLUSIONS

In children with neuromuscular disorders, AGG of the distal femur is effective in improving degree of fixed knee flexion deformity as well as objective gait parameters. A significant portion of knees experience inadequate correction. Addressing factors associated with correction failure (ie, age and plate placement) may improve the procedure's success.

LEVEL OF EVIDENCE

Level III-case control study.