Acetabular dysplasia is typically characterised by insufficient antero-superior femoral head coverage. It is postulated (yet unproven) that patients with dysplasia compensate by reducing pelvic tilt (anterior pelvic rotation), effectively retroverting their acetabulum to improve antero-superior cover. We aimed to 1) define pelvic tilt (PT) in patients with bilateral and unilateral dysplasia, and 2) quantify PT changes following a successful periacetabular osteotomy (PAO). We retrospectively reviewed 16 patients (14 females) who underwent successful, bilateral, staged, PAOs (32 PAOs). These cases were matched for age and gender with 32 unilaterally dysplastic hips that underwent successful PAO for a similar degree of acetabular dysplasia as per pre-operative imaging. Supine and AP radiographs pre-PAO and at latest follow-up were used to measure centre-edge-angle (CEA) and Tönnis-angle (TA). PT was measured using two validated methods (Sacro-Femoral-Pubic (SFP) angle and Pubic-Symphysis to Sacro-Iliac (PS-SI) Index with excellent correlation (ρ=0.8, p<0.001).Introduction
Patients/Materials and Methods
