Purpose

The incidence of hip displacement in children with cerebral palsy is approximately 30% in large population based studies. The purpose of this study was to report the long-term effect of hip surgery on the incidence of hip displacement using a newly validated Cerebral Palsy (CP) hip classification.

Proximal femoral deformity is common in children with cerebral palsy (CP), contributing to hip instability and ambulation difficulties. This population-based cohort study investigates the prevalence and significance of these deformities in relation to Gross Motor Function Classification System (GMFCS) level.

Children with a confirmed diagnosis of CP born within a three-year period were identified from a statewide register.

Motor type, topographical distribution and GMFCS level were obtained from clinical notes. Neck Shaft Angle (NSA) and Migration Percentage (MP) were measured from an anteroposterior pelvis x-ray with the hips internally rotated. Measurement of FNA was by the Trochanteric Palpation Test (TPAT) or during fluoroscopic screening of the hip with a guide wire in the centre of the femoral neck.

Linear regression analysis was performed for FNA, NSA and MP according to GMFCS level.

292 children were eligible. FNA was increased in all GMFCS levels. The lowest measurements were at GMFCS levels I and II p<0.001. GMFCS levels III, IV, and V were uniformly high p<0.001. Neck shaft angle increased sequentially from GMFCS levels I to V (p<0.001). This study confirms a very high prevalence of increased FNA in children with CP in all GMFCS levels. In contrast, NSA and MP progressed step-wise with GMFCS level.

We propose that increased FNA in children with CP represents failure to remodel normal fetal alignment because of delay in ambulation and muscle imbalance across the hip joint. In contrast, coxa valga is an acquired deformity and is largely related to lack of weight bearing and functional ambulation.

The high prevalence of both deformities at GMFCS levels IV and V explain the high rate of displacement in these hips and the need for proximal femoral realignment surgery in the prevention and management of hip displacement.

This study evaluates outcomes of hip adductor surgery in children with cerebral palsy in preventing hip displacement. This review is from the perspective of an extended follow-up (beyond 3 years in contrast to currently available literature) and the Gross Motor Function Classification System (GMFCS).

A retrospective audit was performed of children with cerebral palsy aged 2 to 10 years who had primary adductor surgery at the Royal Children’s Hospital Melbourne between January 1994 and December 2004. These children had hip migration percentages (MP) greater than 30% and been followed up for a minimum 12 months post-operatively.

We have tested the reliability of a recently reported classification system of hip morphology in adolescents with cerebral palsy in whom the triradiate cartilage was closed. The classification is a six-grade ordinal scale, based on the measurement of the migration percentage and an assessment of Shenton’s arch, deformity of the femoral head, acetabular deformity and pelvic obliquity.

Four paediatric orthopaedic surgeons and four physiotherapists received training in the use of the classification which they applied to the assessment of 42 hip radiographs, read on two separate occasions. The inter- and intra-observer reliability was assessed using the intraclass correlation coefficient and found to be excellent, with it ranging from 0.88 to 0.94. The classification in our study was shown to be valid (based on migration percentage), and reliable. As a result we believe that it can now be used in studies describing the natural history of hip displacement in cerebral palsy, in outcome studies and in communication between clinicians.

There is much debate about the nature and extent of deformities in the proximal femur in children with cerebral palsy. Most authorities accept that increased femoral anteversion is common, but its incidence, severity and clinical significance are less clear. Coxa valga is more controversial and many authorities state that it is a radiological artefact rather than a true deformity.

We measured femoral anteversion clinically and the neck-shaft angle radiologically in 292 children with cerebral palsy. This represented 78% of a large, population-based cohort of children with cerebral palsy which included all motor types, topographical distributions and functional levels as determined by the gross motor function classification system.

The mean femoral neck anteversion was 36.5° (11° to 67.5°) and the mean neck-shaft angle 147.5° (130° to 178°). These were both increased compared with values in normally developing children. The mean femoral neck anteversion was 30.4° (11° to 50°) at gross motor function classification system level I, 35.5° (8° to 65°) at level II and then plateaued at approximately 40.0° (25° to 67.5°) at levels III, IV and V. The mean neck-shaft angle increased in a step-wise manner from 135.9° (130° to 145°) at gross motor function classification system level I to 163.0° (151° to 178°) at level V. The migration percentage increased in a similar pattern and was closely related to femoral deformity.

Based on these findings we believe that displacement of the hip in patients with cerebral palsy can be explained mainly by the abnormal shape of the proximal femur, as a result of delayed walking, limited walking or inability to walk. This has clinical implications for the management of hip displacement in children with cerebral palsy.

Between July 2000 and April 2004, 19 patients with bilateral spastic cerebral palsy who required an assistive device to walk had combined lengthening-transfer of the medial hamstrings as part of multilevel surgery. A standardised physical examination, measurement of the Functional Mobility Scale score and video or instrumented gait analysis were performed pre- and post-operatively. Static parameters (popliteal angle, flexion deformity of the knee) and sagittal knee kinematic parameters (knee flexion at initial contact, minimum knee flexion during stance, mean knee flexion during stance) were recorded. The mean length of follow-up was 25 months (14 to 45).

Statistically significant improvements in static and dynamic outcome parameters were found, corresponding to improvements in gait and functional mobility as determined by the Functional Mobility Scale. Mild hyperextension of the knee during gait developed in two patients and was controlled by adjustment of their ankle-foot orthosis. Residual flexion deformity > 10° occurred in both knees of one patient and was treated by anterior distal femoral physeal stapling. Two children also showed an improvement of one level in the Gross Motor Function Classification System.

Introduction and Aims: We investigated the hypothesis that the effects of muscle-tendon surgery could be controlled or ‘dosed’ by varying the location of intramuscular tenotomy (IMT) or fascial striping within the muscle-tendon unit (MTU). We performed a series of randomised trials in paired cadaver MTUs of tibialis posterior, semitendinosus, gracilis and semimembranosus.

Method: Following dissection of 10 paired cadaver MTUs of the above-mentioned muscles, we performed a series of randomised trials in which each pair of MTUs received a low or high IMT. ‘Low IMT’ was defined as an IMT performed two centimetres proximal to the distal musculotendinous junction. ‘High IMT’ was performed two centimetres distal to the start of the first tendinous fibres in the proximal muscle belly. The force-length characteristics were then determined by tensile load testing until failure on an Instron machine. The load and lengthening at failure for each pair of MTUs were compared by paired t test.

Results: As expected, there were significant differences in the load versus length curves for different muscles and for different simulated surgeries (IMT versus fascial striping). The mean load at failure was significantly lower for all low IMTs compared to high IMTs in all MTUs tested e.g. tibialis posterior: mean difference low versus high = 13N (95% CI 6.8, 19.2 p< 0.001). The lengthening at failure was also greater for low IMTs than for high IMTs. The difference reached statistical significance only in tibialis posterior.

Conclusions: The site of the intramuscular surgery or fascial striping has a direct bearing on the force versus lengthening curve. We hypothesise that the same principle applies during muscle tendon surgery in children with spastic contractures and that it may be possible to graduate surgical lengthening, according to the correction required.

Introduction and Aims: We present the preliminary results of patellar tendon shortening (PTS), for severe crouch gait in children with spastic cerebral palsy who were household ambulators.

Method: We performed bilateral patellar tendon shortening in 15 patients with severe spastic diplegia between May 1996 and January 2002. The majority had acquired crouch gait because of isolated lengthening of the Achilles tendons in childhood and presented with anterior knee pain and rapidly deteriorating gait and function. The PTS procedure included dividing the patellar tendon in its mid portion, and performing an overlapping repair by suturing the distal tendon to the distal pole of the patella and the proximal segment to the tibial tubercle. The corrected position of the patella was maintained by a K-wire passed transversely through the patella and incorporated into a cylinder plaster, with the knee in extension, for a period of six weeks. Correction of knee flexion deformity was achieved by transfer of semitendonosis to the distal femur or extension osteotomy of the distal femur.

Results: Rehabilitation was predictably slow but all patients regained their pre-operative mobility status within one year and the majority surpassed their pre-operative functional level by two years after surgery. There were no tendon ruptures or growth disturbance in the proximal tibia. Average age at the time of surgery was 14.2 years (10–19 years). Mean follow-up was 27 months (12–48 months). Pre- and post-operative Insall index in 17 knees was 0.68cm (0.46 to 1.07cm, SD=0.16cm) and 0.85cm (0.56 to 1.08cm, SD=0.20) respectively (p< 0.001 Students-t test). Pre-operatively, only three sides had a normal index, but post-operatively 14 sides had a normal index. Crouch gait improved in all patients who were reclassified as community ambulators. Thirteen patients still needed crutches. One patient continued to complain of bilateral knee pain 12 months after surgery, had insufficient correction according to the Insall index (0.58cm on the left 0.56cm on the right).

Conclusion: Severe crouch gait after appropriate surgical and orthotic management, maybe due to patella alta, quadriceps and ankle plantarflexors insufficiency. We present preliminary results of a salvage procedure, patellar tendon shortening, which seems a reasonable option to treat complex crouch gait in selected patients with cerebral palsy.

Torsional deformities of the tibia are common in children, but in the majority both the torsion and the associated disturbance of gait resolve without intervention. There are, however, a significant number of children and adults with neuromuscular disease who present with pathological tibial torsion, which may require surgical correction.

We conducted a prospective study in two centres, to investigate the outcome of supramalleolar derotation osteotomy of the tibia, using internal fixation with the AO-ASIF T plate. A range of outcome variables was collected, prospectively, for 57 patients (91 osteotomies), including thigh foot angle, foot progression angle, post-operative complications and serial radiographs. Correction of thigh foot angle and foot progression angle was satisfactory in all patients. Three major complications were recorded; one aseptic nonunion, one fracture through the osteotomy site after removal of the plate and one distal tibial growth arrest.

We found that supramalleolar derotation osteotomy of the tibia, with AO-ASIF T plate fixation is an effective method for the correction of torsional deformities of the tibia and the associated disturbances of gait in children and adults with neuromuscular disease, with a 5.3% risk of major complications.