Shelton J, Airey G, Dorman S, Wright D, Bruce C
DDH is present in 3.6/1000 live births in the UK. Patients who have a delayed diagnosis or refractory DDH will require a redirectional osteotomy to provide enhanced acetabular coverage allowing the femoral head to mould the acetabulum and create a congruent joint. Previous studies have demonstrated acetabular retroversion in patients who underwent Salter’s osteotomy on plain radiographs assessed for crossover sign. Acetabular retroversion has been shown as a risk factor in FAI and OA of the hip.
This study aims to accurately assess acetabular version using cross-sectional imaging in the immediate per-operative period.
All patients undergoing salter’s osteotomy were identified using the AHCH DDH database. Inclusion criteria were: Salters osteotomy for DDH, unilateral with a post op CT scan and adequate notes available. We excluded bilateral DDH and those without CT scan. Axial images were assessed for acetabular version (AV) with a modification of Abousamra’s technique by two authors with any discrepancies reviewed by a senior author. Measurements for the pathological hip and control hip were taken and Wilcoxon signed-rank test (<0.05) used for statistical analysis. Inter-observer reliability was assessed with Intra-class correlation coefficient (>0.7).
108 patients were identified with 92 included. Average age was 20.5 months, 81.5% female and 65% left sided. No acetabular retroversion was identified with mean AV 15.86® in salters hips and 12.99® in control hips (p=<0.001). Interrater reliability was 0.765 controls and 0.9 salters. No crossover sign was seen on follow up radiographs.
This is the largest study assessing AV after salters osteotomy and provides compelling evidence that retroversion post salters is a fallacy especially in conjunction with emerging evidence from comparative studies between cross-sectional imaging and radiographs showing poor reliability of retroversion on radiographs. This will aid adult hip surgeons with acetabular positioning as the TAL is excised in the majority of DDH surgeries.