The causes and management of nonunion of femoral subtrochanteric shortening osteotomy in a THA patient: a case report

BACKGROUND: Total hip arthroplasty (THA) is considerably difficult to perform in patients with Crowe type IV developmental dysplasia of the hip (DDH). Some Crowe type IV DDH patients require a femoral subtrochanteric shortening osteotomy to equalize the length of the lower extremities and decrease the difficulty of intraoperative reduction. Subtrochanteric transverse osteotomy has been proven to have superior clinical efficacy, but some cases of nonunion occur. CASE PRESENTATION: We present the case of a 62-year-old male patient who underwent right THA with femoral subtrochanteric transverse osteotomy due to Crowe type IV DDH. Nonunion of the osteotomy occurred during the follow-up period. In July 2017, the patient underwent right THA and femoral subtrochanteric transverse osteotomy due to Crowe type IV DDH. In November 2017, a slight feeling of bone rubbing and slight pain in the hip were reported. The ends of the osteotomy had rotated and united poorly. However, the patient requested to undergo continued observation. In December 2017, the patient reported an obvious sensation of bone rubbing and aggravated hip pain. The ends of the osteotomy had rotated and continued to exhibit nonunion. On December 26, 2017, the patient was treated with plate and screw internal fixation with bone morphogenetic protein (BMP) following our suggestion. In August 2018, the ends of the osteotomy had united after internal fixation was applied. CONCLUSIONS: THA with femoral subtrochanteric transverse osteotomy exhibits good efficacy for the treatment of patients with Crowe type IV DDH. However, postoperative nonunion occurs in a small number of cases. The causes of nonunion should be analysed, and effective measures should be taken to prevent this situation. Plate and screw internal fixation with BMP is an effective treatment for nonunion of the ends of an osteotomy.