Is muscle lengthening or bony surgery better for young children with cerebral palsy who have hip displacement?

INTERVENTION: Varus derotation osteotomy (VDRO) of the proximal femur: Bony reconstructive surgery will be by VDRO and will follow a standard surgical protocol as follows: 1. Epidural anaesthesia with a dosing regimen individualised to each child – as per current practice 2. Careful examination of hip abduction range under anaesthesia and bilateral open lengthening of the adductor longus, adductor brevis, gracilis and psoas muscles, through a groin skin crease incision, until there is at least 60 degrees of abduction in each hip, and symmetric abduction is restored. 3. Bilateral femoral VDRO will be performed via a lateral approach, using a 90 or 100 degree blade plate for stable internal fixation, aiming for a neck shaft angle of between 90 and 100 degrees, with derotation to 10 degrees of anteversion. Bilateral VDROs, performed by a team of 2 surgeons, takes approximately 90 minutes. CONDITION: Cerebral Palsy Hip displacement PRIMARY OUTCOME: Hip migration percentage (MP): ; ; MP is a measure of the proportion of the femoral head that is sitting outside of the acetabulum, expressed as a percentage. A hip x‐ray (AP Pelvis) will be taken at each study visit. Participants will be positioned for the x‐ray according to a standardised protocol to ensure accurate measurement of migration percentage is possible. MP will be measured directly from the x‐ray on‐screen and by a standardised method. SECONDARY OUTCOME: Caregiver Priorities and Child Health Index of Life with Disabilitities (CPCHILD): ; ; The participant’s parent/guardian will be asked to complete the CPCHILD questionnaire during their attendance at each study visit. The questionnaire asks carers to consider how each of the listed activities is usually performed by/for their child, to rate how difficult each of these activities were in the previous 2 weeks, and identify the level of assistance that was required to help their child perform the activities. Gross Motor Function Measure (GMFM): ; ; The GMFM will be used to measure time to return to baseline function following surgery. The Gross Motor Function Measure (GMFM) was developed to measure change in gross motor function over time in young people with cerebral palsy. The measure covers five dimensions of activity: Lying and Rolling; Sitting; Crawling; Standing; and Walking, Running and Jumping. Paediatric Pain Profile: ; ; The participant’s parent/guardian will be asked to record their child’s pain behaviours using the Paediatric Pain Profile (PPP). The PPP asks parents to use a 20 item scale to rate behaviours from their child that have been identified as being associated with pain. Safety and adverse events: ; ; Details of adverse events will also be recorded as follows: ; ; Surgical Adverse Events ; Blood transfusion: Recorded as required or not. It is expected that only children undergoing VDRO might require transfusion. ; Surgical site infection (SSI): SSI will be recorded according to the definitions and classifications of the Center for Disease Control (CDC). Treatment required for SSIs will be recorded, including dressing change, antibiotics (oral or intravenous as an outpatient or inpatient), any readmission, re‐operation or removal of hardware required. ; Hardware issues: Symptomatic prominence, hardware failure (breakage) or fracture will be recorded, including management required. ; ; General/Medical Adverse Events: ; Urinary Tract Infection: Detail will be recorded of any child developing a urinary tract infection following surgery, including time to resolution. ; Severe Vomiting/nausea: Severe nausea of vomiting requiring medication will be recorded. ; Severe consitpation: Severe contispation delaying discharge will be recorded, including whether it was resolved prior to discharge ; Cast issues: If a child develops any adverse events from plaster casting, including skin excoriation, cellulitis and pressure sores, either during admission or during the follow‐up period, details will be recorded of management and time to resolution. ; Heterotopic Ossification (HO): HO will be classified from pelvic radiographs at each study time point using a system described by Krum and Miller to classify HO after orthopaedic surgery in children with CP. This classification describes HO by both radiographic and clinical criteria. Asymptomatic HO with a lesion of less than half the width of the ipsilateral femoral neck (Classification IA) will not be considered an adverse event. ; Delayed union or non‐union: Any delay in bone union or non‐union evident on the pelvic radiograph will be recorded at follow‐up visits. If there is delay in union, time to union will be recorded. ; Respiratory function: Detail will be recorded of any child developing a respiratory tract infection following surgery, including whether the infection resolved prior to discharge, whether an ICU admission was required or whether the child was re‐admitted with a respiratory infection after discharge post‐surgery. ; ; All adverse events will be classified using a modified version of the Clavien‐Dindo Classification which has previously been applied to bony surgery for hip displacement in cerebral palsy. ; INCLUSION CRITERIA: 1. A diagnosis of cerebral palsy and be registered with the Victorian Cerebral Palsy Register, 2. Non‐ambulant, with gross motor function classified at level IV or V by the GMFCS, 3. Aged between 4 and 10 years at the time of surgery, 4. Hip migration between 30 and 60% in one or both hips at the time of randomisation, 5. Hip abduction <40 degrees in one or both hips at the time of randomisation, and 6. A recommendation from the treating Orthopaedic Surgeon to proceed to surgery for management of hip displacement.