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.

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.