Minimally displaced intra-capsular femoral neck fractures in the elderly--comparison of multiple threaded pins and sliding compression screws surgical techniques.

PURPOSE To determine the outcome of treatment for minimally displaced femoral neck fractures using multiple threaded pins versus sliding compression screws for internal fixation. METHODS The medical records of 62 consecutive elderly patients with minimally displaced intra-capsular femoral neck fractures who underwent internal fixation of the fracture (37 with multiple threaded pins, and 25 with sliding compression screws) were reviewed. Clinical and radiological assessment of fracture healing at follow-up visits were noted. RESULTS In the 55 patients seen for follow-up at 3 months, 21.9% (n=7) of those treated by pinning demonstrated non-union of the fracture, and 0% of fractures treated with sliding compression screws (p=0.02). 46 patients were seen for follow-up at one year, with 10% (n=2) of those treated with sliding compression screws found to have osteonecrosis of the femoral head. The 2 fractures in the group treated by pinning demonstrating non-union at 3 months failed to unite by one year (p=0.11). 34 patients were seen for follow-up for at least 2 years, with no additional complications noted. CONCLUSION Using sliding compression screws to treat minimally displaced femoral neck fractures can achieve a higher union rate than using pinning. The reason may be the better stability in the osteoporotic bone. However, osteonecrosis of the femoral head may occur with use of sliding compression screws because of greater intramedullary vascular damage as a result of wider reaming.