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

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 center-edge angle, acetabular index (AI), and acetabular depth index (ADI). We measured the surface area of the femoral head ossific nucleus on anterior-posterior 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 month-follow-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.