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

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.

Pelvic Tilt in Adults With Cerebral Palsy and Its Relationship With Prior Hamstrings Lengthening

BACKGROUND

Current studies assessing the change in pelvic tilt for ambulatory patients with cerebral palsy (CP) after surgical hamstring lengthening (SHL) lack a comparison cohort without prior SHL and are limited to younger patients. This study presents gait data of middle-aged adults with CP, primarily focusing on the pelvis, and compares pelvic tilt, trunk tilt, and knee flexion between those with and without prior SHL.

MATERIALS AND METHODS

A consecutive series of 54 adults with CP, a mean age of 36±13 years, and Gross Motor Function Classification System (GMFCS) levels I-III were included. Thirty-two (59%) had SHL performed at a mean age of 8±5 years. Three-dimensional gait analysis data prospectively collected at a mean of 28±14 years postoperatively were retrospectively analyzed. Chi-square tests were used to compare demographic and surgical history data and statistical parameter mapping was used to compare knee flexion during stance and pelvic and trunk tilts during the gait cycle between SHL and SHL-naive groups.

RESULTS

Age, GMFCS level, sex, race, topography, and ethnicity were not different between the groups (P=.217-.612). Anterior pelvic tilt throughout gait was significantly greater in the SHL group compared with the SHL-naive group (63%-87%; P=.033). This difference was augmented after accounting for other surgical history and revision SHL (0%-32%, P=.019; and 46%-93%, P=.007).

CONCLUSION

Within a cohort of adults with CP, GMFCS levels I-III, and a mean age of 36 years, those with a history of SHL, performed a mean of 28 years prior to 3-dimensional gait analysis, walked with increased anterior pelvic tilt compared with those without a history of SHL. [Orthopedics. 2024;47(5):270-275.].

Distal femoral osteotomy and patellar tendon advancement for the treatment of crouch gait in patients with bilateral spastic cerebral palsy

BACKGROUND

Crouch gait, or flexed knee gait, represents a common gait pattern in patients with spastic bilateral cerebral palsy (CP). Distal femoral extension and/or shortening osteotomy (DFEO/DFSO) and patellar tendon advancement (PTA) can be considered as viable options when knee flexion contractures are involved. Better outcomes have been reported after a combination of both, independently of the presence of knee extensor lag. In this study, we evaluated the clinical and kinematic outcomes of these procedures.

PATIENTS AND METHODS

We reviewed a cohort of 52 limbs (28 patients) who were treated for crouch gait by DFEO/DFSO alone (group 1, n = 15) or DFEO/DFSO + PTA (group 2, n = 37) as a part of single event multilevel surgery (SEMLS). The mean age at surgery was 14 years, and the mean follow-up time was 18 months. The physical examination data and three-dimensional standardized gait analysis were collected and analyzed before the surgery and postoperatively.

RESULTS

Overall knee range of motion improved in all limbs. The knee flexion decreased significantly in both groups at initial, mid, and terminal stance. Hip flexion significantly decreased in mid-stance for limbs in group 2. Both clinical and gait parameters were most improved in limbs who underwent DFEO/DFSO + PTA. Increased pelvic tilt was observed in both groups after surgery.

CONCLUSION

Although DFEO/DFSO alone was successful in correcting knee flexion contractures, PTA has helped to improve knee extensor lag and knee extension during gait.

LEVEL OF EVIDENCE

Therapeutic level IV.

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.

Anterior Distal Femoral Hemiepiphysiodesis Does Not Change Pelvic Tilt in Children With Cerebral Palsy

BACKGROUND

Anterior distal femoral hemiepiphysiodesis (ADFH) is a surgical treatment choice to correct flexed knee gait and fixed knee flexion deformities in children with cerebral palsy who are skeletally immature. Increased anterior pelvic tilt has been reported after surgeries that correct knee flexion deformities, including hamstring lengthening (HSL) and distal femoral extension osteotomies, but anterior pelvic tilt has not been studied after ADFH. We hypothesized that anterior pelvic tilt would increase after ADFH, especially when combined with HSL, and it would correlate with the change in minimum knee flexion in stance and dynamic hamstring lengths.

METHODS

Thirty-four eligible participants (age: 13.0, SD: 2.0) were included. Change in mean pelvic tilt across the gait cycle was compared as a function of clinical and gait parameters using linear mixed models. The relationship of change in pelvic tilt to change in other variables was examined using Pearson correlation.

RESULTS

Overall, anterior pelvic tilt increased significantly after ADFH by 4.4 degrees ( P = 0.02). Further, the analysis revealed anterior pelvic tilt only increased significantly in the group that had concurrent HSL (11.1 degrees, P < 0.001). Overall, minimum knee flexion significantly decreased (increase in knee extension) in stance (-19.1 degrees, P < 0.001) and there was an increase in maximum normalized dynamic hamstring lengths (0.03, P < 0.001). The anterior pelvic tilt increased significantly in Gross Motor Function Classification System levels III to IV (5.9 degrees, P = 0.02) but did not change significantly in Gross Motor Function Classification System I to II (2.5 degrees, P = 0.37). Change in pelvic tilt was correlated with change in maximum dynamic hamstring lengths ( r = 0.87, P < 0.0001) and change in minimum knee flexion in stance ( r = -0.71, P < 0.0001).

CONCLUSIONS

Anterior distal hemiepiphysiodesis without concurrent HSL for flexion knee deformities does not result in increased anterior pelvic tilt. Surgeons should consider anterior distal hemiepiphysiodesis in patients with cerebral palsy and flexed knee gait, who preoperatively have long dynamically modeled hamstrings, are skeletally immature, and when maintenance of pelvic tilt is desired.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

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.

Guided Growth of the Proximal Femur for the Management of the 'Hip at Risk' in Children with Cerebral Palsy-A Systematic Review

BACKGROUND

Guided growth is frequently used to modify lower-limb alignment in children, and recently temporary medial hemiepiphysiodesis of the proximal femur (TMH-PF) has been used for the management of hips at risk of subluxation in cerebral palsy (CP) patients. The aim of our study was to evaluate the efficacy of TMH-PF in the management of neuromuscular hip dysplasia in children with cerebral palsy.

METHODS

A systematic search of the literature was performed by using PubMed, EMBASE, CINAHL, MEDLINE, Scopus and Cochrane databases. Pre- and postoperative radiographic changes of the migration percentage (MP), head-shaft angle (HSA) and acetabular index (AI) were included in a meta-analysis. Secondary outcomes were treatment complication rates, technical considerations and the limitations of this novel technique.

RESULTS

Four studies (93 patients; 178 hips) met the eligibility criteria for inclusion in the meta-analysis. All three radiographic measurements showed significant changes at a minimum of 2 years of follow-up. Mean changes for MP were 8.48% (95% CI 3.81-13.14), HSA 12.28° (95% CI 11.17-13.39) and AI 3.41° (95% CI 0.72-6.10), with I² of 75.74%, 0% and 87.68%, respectively. The serious complication rate was overall low; however, physeal 'growing off' of the screw was reported in up to 43% of hips treated.

CONCLUSION

TMH-PF is an effective and predictable method to treat CP patients with 'hips at risk', and the overall complication rate is low; however, further work is required to identify the best candidates and surgical timing, as well as choice of technique and implant.

Functional and Clinical Outcomes of Combined Simultaneous Bilateral Anterior Distal Femoral Plate Hemiepiphysiodesis and Hamstrings Release in Management of Knee Flexion Contractures in Children With Neuromuscular Disorders

BACKGROUND

We examined the clinical and functional outcomes of the simultaneous anterior distal femoral 8-plate hemiepiphysiodesis (ADF8PH) and hamstring release, for fixed knee flexion deformity in children with neuromuscular disease. To our knowledge, no published evidence is available that reports the outcomes of this combined techniques.

METHODS

Electronic medical records were retrospectively reviewed for 19 consecutive children who underwent bilateral ADF8PH and concomitant hamstrings release in our institution from 2012 to 2019. Relevant demographics, Gross Motor Functional Classification Score and preoperative and postoperative knee flexion contractures and popliteal angles were documented.

RESULTS

The average age at the time of operation was 12±2.1 years. There were 15 males and 4 females. Diagnoses included cerebral palsy (n=16), Cornelia de Lange syndrome (n=1), hereditary spastic paraplegia type 56 (n=1) and fructose-1,6 bisphosphonate aldose B deficiency (n=1). Mean length of follow-up was 3.8 years (range: 1.5 to 7 y). Mean fixed knee flexion deformity improved from 28.9 to 13.4 degrees (P<0.001) at an average correction rate of 0.94 degrees per month. Mean popliteal angle improved from 81.8 to 44.4 degrees (P<0.001) in the early postoperative phase and to 51.8 degrees (P<0.001) in latest clinic review. Mean time to correction was 18.9 months. The agreed treatment goals of maintaining or promoting the use of standing frame and spinal/postural symmetry was attained in 18 patients (94.7%). Postoperative knee pain was reported in 2 cases (10.5%). We report 2 complications; 1 case of neurapraxia and 1 case of sepsis because of respiratory infection.

CONCLUSION

Simultaneous bilateral ADF8PH with hamstrings release is a promising effective technique for correction of knee flexion contractures in skeletally immature individuals with neuromuscular disabilities. Our findings demonstrate improvement in clinical outcomes and maintaining functional outcomes, indicating the validity of this approach as a satisfactory, less invasive alternative in the management of this deformity.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

Feasibility of microwave ablation of the vertebral growth plate for spine growth regulation: a preliminary study

PURPOSE

To explore the feasibility of microwave ablation (MWA) of the vertebral growth plate as a minimally invasive treatment for early-onset scoliosis.

MATERIALS AND METHODS

One side of the L1-L3 vertebral growth plates were ablated using different MWA powers. Ablation safety and size were examined. Subsequently, L1-L3 vertebral growth plates were ablated on one side for 40 s at 20 W. At 2, 4, and 6 weeks after the ablation, growth changes of the spine were observed.

RESULTS

No piglets died during and after ablation, and all had modified Tarlov Grade 5. The safe MWA time (time for safely ablating the vertebral growth plate) was 17.0 ± 1.5 s at 50 W, 23.0 ± 2.3 s at 40 W, 31.0 ± 3.1 s at 30 W, 47.0 ± 3.7 s at 20 W, 70.0 ± 4.2 s at 15 W, and 158.0 ± 5.0 s at 10 W. With power <15 W, the vertebral growth plate could not be effectively ablated within the safe ablation time. Within the safe ablation times, the MWA size on hematoxylin and eosin slices on a transverse diameter was between 7 and 10 mm; and that on longitudinal diameter was mainly determined by the ablation needle length. Moreover, the growth plate and annulus fibrosus on the ablated side grew poorly over time, the vertebral body showed significant wedge-shaped changes, and the spine showed significant unbalanced growth.

CONCLUSION

MWA of the vertebral growth plate can be performed safely when accompanied with appropriate thermometry, and could be a new minimally invasive strategy in regulating spine growth.

Angular Deformities of the Knee in Children Treated with Guided Growth

Introduction:

The guided growth technique is an alternative to corrective osteotomy for treating angular deformities of the extremities. It has the advantage of being minimally invasive and is effective in a growing child. This study reports on the outcome of guided growth technique using a plate in correcting knee angular deformities.

Material and Methods:

We conducted a retrospective study of children with angular deformity of the knee treated by the guided growth technique from January 2010 to December 2015 in a tertiary centre. The guided growth technique was done using either the flexible titanium plate (8-plate) or the 2-hole reconstruction plate. Correction of deformity was assessed on radiographs by evaluating the mechanical axis deviation and tibiofemoral angle. The implants were removed once deformity correction was achieved.

Results:

A total of 17 patients (27 knees) were evaluated. Twenty-two knees (81.5%) achieved complete correction of the deformity. The median age was 4.0 (interquartile range 3.0-6.0) years and the median Body Mass Index (BMI) was 26.0 (25.0-28.0). There were 7 unilateral and 10 bilateral deformities with different pathologies (14 tibia vara, 3 genu valgus). The median rate of correction was 0.71° per month. One patient (1 knee) had screw pull-out and two patients (4 knees) had broken screws in the proximal tibia. Three patients (5 knees) failed to achieve complete correction and were subsequently treated with corrective osteotomies. Out of five patients (8 knees) who were followed-up for at least 12 months after removal of hardware, two had rebound deformities. No permanent growth retardation occurred in our patients.

Conclusion:

Our outcome for guided growth to correct knee angular deformity was similar to other studies. Guided growth is safe to perform in children below 12 years old and has good outcome in idiopathic genu valgus and Langeskiold II for tibia vara. Patients should be observed for recurrence until skeletal maturity following implant removal.

Growth modulation with tension-band plates for the correction of paediatric lower limb angular deformity: current concepts and indications for a rational use

Growth modulation (GM) with tension-band plates (TBPs) by tethering part of the growth plate is an established technique for the correction of angular deformities in children, and it has increasingly supplanted more invasive osteotomies.Growth modulation with TBPs is a safe and effective method to correct a variety of deformities in skeletally immature patients with idiopathic and pathological physes. The most common indication is a persistent deformity in the coronal plane of the knee exceeding 10°, with anterior and/or lateral joint pain, patellofemoral instability, gait disturbance, or cosmetic concerns. GM has also shown good results in patients with fixed flexion deformity of the knee and ankle valgus.This paper reviews the history of the procedure, current indications, and recent advances underlying physeal manipulation with TBPs. Cite this article: EFORT Open Rev 2021;6:658-668. DOI: 10.1302/2058-5241.6.200098.

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.

What's New in the Orthopaedic Treatment of Ambulatory Children With Cerebral Palsy Using Gait Analysis

BACKGROUND

Limb deformities in ambulatory children with cerebral palsy (CP) are common. The natural history of lower extremity deformities is variable and the impact on gait is managed with many treatment modalities. Effective interventions must consider the underlying pathophysiology, patient-specific goals, and incorporate objective outcome assessment. Evaluation and treatment include observation, tone management multilevel orthopaedic surgery to address muscle contractures and bony deformities, and the use of gait analysis for preoperative and postoperative assessment.

METHODS

A PubMed search of the orthopaedic literature for studies published between January 2016 and February 2019 was performed. Eligible abstracts included the use of 3-dimensional instrumented gait analysis in the evaluation and treatment of the lower extremities in ambulatory children with CP. Seven hundred twenty abstracts were reviewed, with 84 papers identified as eligible, of which 45 full manuscripts were included for detailed review.

RESULTS

The review summarized recent advances regarding the treatment of torsional alignment, knee deformities and clinical gait evaluation with visual assessment tools compared with instrumented gait analysis.

CONCLUSIONS

Gait analysis of ambulatory children with CP remains essential to evaluation and surgical decision-making. Promising results have been reported with the goal of maintaining or reaching a higher level of function and increased endurance.

LEVEL OF EVIDENCE

Level IV-literature review.

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.