[Application of absorbable pins for reconstructing pelvic stability in Salter innominate]

To investigate the effectiveness of absorbable pins for reconstructing pelvic stability in Salter innominate osteotomy for treating development dysplasia of the hip (DDH).

Between January 2003 and December 2008, 392 patients (440 hips) with DDH underwent a Salter procedure. There were 68 boys (82 hips) and 324 girls (358 hips) with a mean age of 3 years and 3 months (range, 1 year and 6 months-5 years). According to Tonnis classification criteria, 13 hips were rated as grade I, 304 hips as grade II, 82 hips as grade III, and 41 hips as grade IV. Based on the degree of displacement of the femoral head and acetabular index on the anteroposterior pelvic X-ray film, operation method was selected before operation. A total of 341 hips were managed with open reduction and Salter innominate osteotomy, and 99 hips with Salter innominate osteotomy and femoral shortening rotating osteotomy. All cases underwent autologous iliac crest grafting and fixation between osteotomy sites and bone graft with 2 absorbable pins.

At 1 day after operation, anteroposterior pelvic X-ray examination showed concentric reduction in all hips, having no instability of the joint of the osteotomy sites or bone graft shifting. A total of 368 patients (413 hips) were followed up 1 to 7 years (mean, 3 years and 10 months). At 3 months after operation, no bone graft in stability or shift, and sliding or loosening of pins occurred. At last follow-up, concentric reduction rate was 100%; after hip loading, 358 patients had no claudication and limited hip activities, who had the stability of hips and negative Allis and Ortalani signs. No abnormal height growth was observed in all patients. According to Mckay's hip function evaluation criteria, the results were excellent in 390 hips, good in 16 hips, and fair in 7 hips, with an excellent and good rate of 98.3%; according to Severin X-ray criteria, the results were excellent in 386 hips, good in 17 hips, and fair in 10 hips, with an excellent and good rate of 97.6%.

Absorbable pins can replace steel pins for fixation of the osteotomy sites and bone graft in Salter innoninate because of flexible and convenient operation without a need for reoperation of steel pins extraction.