FUNCTIONAL OUTCOME OF COMPLEX HIP ARTHROPLASTY TREATMENT OF METASTATIC DISEASE TO THE ACETABULUM

Abstract

The outcome of complex acetabular reconstruction was evaluated in twenty-one patients who were confined to a wheelchair or bed because of pain from acetabular metastases. Reconstruction rings were used where bone loss exceeded 50% of the acetabulum. Six roof reinforcement-rings, eight ilioischial-rings and eight Harrington reconstructions were performed. All but two patients(90%) became ambulatory without pain. Median survival was nine months. Two patients underwent acetabular revision for recurrence. These results support the role of acetabular reconstruction for palliation of pain in appropriate patients with acetabular metastases.

Metastatic disease of the acetabulum is painful and disabling. Operative intervention is indicated in certain patients with pathologic fractures, and non-responders to adjuvant treatment. The functional outcome of hip arthroplasty with reconstruction rings was evaluated in twenty-one patients with acetabular metastases between 1989 and 2001. Preoperatively all patients were confined to a wheelchair or bed and used significant narcotic medications. Preoperative radiotherapy was employed in eighteen cases (90%) and 30% had undergone chemotherapy.

AAOS classification of the acetabular lesion revealed: six-type II, seven-type III and eight-type IV deficiencies. All cases required a reconstruction ring due to bone loss exceeding 50% of the acetabular dome. Six roof reinforcement rings, eight ilioischial rings and eight Harrington reconstructions with rings were performed in this group. Determination of the reconstructive technique was based on preoperative computerized tomography and intraoperative examination of the acetabular deficiency.

All but two patients (90%) became ambulatory without significant pain. Eleven patients used a walker or two canes and nine walked with one or no canes. Median survival was nine months and patients with visceral involvement had a shorter duration. Eight early post-operative complications developed in six patients (29%). In two patients the acetabular construct failed with cup migration due to locally recurrent disease; both were successfully revised.

The results of complex acetabular reconstruction for metastatic disease validate its role for palliation of pain and to improve ambulatory status. Preoperative planning with computerized tomography can assist in classifying acetabular bone loss and determining optimal reconstruction technique.