Dislocation rate after hip hemiarthroplasty in patients with tumor-related conditions.

Background: Hemiarthroplasty is frequently used to treat femoral neck insufficiency resulting from neoplastic disease in the proximal part of the femur. The authors of a recent study analyzed the dislocation rates following hemiarthroplasty but excluded patients with tumor involvement of the site of the surgery as they hypothesized that the dislocation rates would be markedly higher in such patients. The current study was performed to compare the dislocation rate following hemiarthroplasties performed in patients without tumor involvement with the rate following hemiarthroplasties in patients with tumor involvement of the surgical site.

Methods: Patients who had undergone hemiarthroplasty following resection of a tumor involving the proximal part of the femur were identified in a total joint registry, and the patients' charts were reviewed retrospectively to determine dislocation rates, preoperative conditions, and postoperative outcomes and treatments. Between 1974 and 2001, 1812 patients were treated with hemiarthroplasty for reasons other than tumor involvement and 320 hemiarthroplasties were performed because of tumor-related conditions. The patients who were treated for a tumor-related condition were younger, and a higher proportion of them were men.

Results: The ten-year dislocation rate after the hemiarthroplasties performed for tumor-related conditions (10.9%) was higher than that following the hemiarthroplasties performed for non-tumor-related conditions (2.1%) (p = 0.002). The median time to dislocation in the patients with a tumor-related condition (twenty-four days) was shorter than that for the patients without tumor involvement (thirty-seven days). Preservation of the greater trochanter in patients with tumor involvement did not have a significant influence on the dislocation rate, but it showed a favorable trend toward decreasing that rate (hazard ratio = 3.5, p = 0.06).

Conclusions: The short-term and long-term dislocation rates associated with hemiarthroplasties performed for a tumor-related condition at the site of the surgery were significantly higher than those associated with hemiarthroplasties performed for reasons other than tumor involvement. Preservation of the greater trochanter showed a trend toward decreasing the likelihood of dislocation following the hemiarthroplasty, and it was more influential than the level of resection and the extent of soft-tissue compromise. We think that preservation of the greater trochanter should be attempted when it is justifiable according to the principles of oncologic surgery.