Early-term hip development following Pemberton osteotomy: a radiological follow-up

Abstract

Objectives: This study aims to evaluate the relationship of early-term radiological changes with development of the hip joint after Pemberton osteotomy.
Patients and methods: This study, which was conducted between January 2010 and December 2014, included 101 hips (26 bilateral) of 75 patients (25 males, 50 females; mean age 31.5 months; range 15 to 71 months) which were performed Pemberton osteotomy due to developmental dysplasia of the hip. Radiologically, we assessed the parameters of centeredge angle, acetabular index (AI), and acetabular depth index (ADI). We measured the surface area of the femoral head ossific nucleus on anteriorposterior pelvic X-rays. We graded the degree of hip dislocation according to Tönnis classification while the femoral head avascular necrosis was graded according to Kalamchi-MacEwen classification. We separated the operated hips in all patients and in only unilaterally operated patients in three groups according to their follow-up durations as 12 months, 12 to 24 months, and more than 24 months. We analyzed the associations of radiological parameters in all follow-up durations.
Results: Mean follow-up duration was 22.5 months (range, 6 to 66 months). Preoperative mean AI was 42.25° (range, 29° to 60°) and last follow-up mean AI was 20.45° (range, 10° to 32°). Preoperative mean ADI was 16.48° (range, 9°-30°) and last follow-up mean ADI was 26.1° (range, 23°-47°). Sixty hips were Tönnis type 4, 26 hips were type 3, and 15 hips were type 2. According to follow-up duration classification; there were 32 hips (21 unilateral) with 12 monthfollow- up, 43 hips (17 unilateral) with 12-24 month-follow-up, and 26 hips (11 unilateral) with more than 24-month follow-up. We applied shortening osteotomy to 18 femurs. According to Kalamchi-MacEwen classification; avascular necrosis type 1 was present in 16 hips, type 2 in two hips, type 3 in three hips, and type 4 in two hips. We performed revision operations for five hips because of recurrent subluxations.
Conclusion: We observed progressive improvements in hip joints and consequently in radiological parameters in the early-term after Pemberton osteotomy.