Functional and oncological outcome of acetabular reconstruction for the treatment of metastatic disease

Background: Metastatic disease of the acetabulum can be painful and disabli ng. Operative intervention is indicated for patients who fail to respond ad equately to nonoperative treatment. We evaluated the functional and oncolog ical outcome of acetabular reconstruction after curettage for the treatment of refractory symptomatic acetabular metastases, Methods: Fifty-five patients with metastatic disease of the acetabulum were treated with operative acetabular reconstruction combined with a total hip replacement. The most common primary tumor was carcinoma of the breast (ei ghteen patients), followed by carcinoma of the kidney (seven patients) and carcinoma of the prostate (seven patients). Forty (73 percent) of the patie nts presented with multiple skeletal metastases, and eighteen (33 percent) had associated visceral metastases. Twenty-eight (51 percent) had severe pa in requiring continuous use of narcotics, twenty-four (44 percent) had mode rate pain requiring periodic use of narcotics, and the remaining three (5 p ercent) had mild pain requiring use of non-narcotic analgesics. Eighteen (3 3 percent) of the patients could not walk, twenty-three (42 percent) needed a walker or crutches, twelve (22 percent) used a single cane, and two (4 p ercent) walked without assistive devices. Intralesional curettage of the tu mor was performed in all of the patients. Fifty-four of the hips were recon structed with a protrusio cup and one, with a hemi-pelvis endoprosthesis. L arge defects were reinforced with cement and pin or screw fixation (the mod ified Harrington technique), which allowed transmission of weight-bearing f orces to the remaining intact pelvis, Thirty-six acetabular reconstructions were performed with antegrade pins or cannulated screws; fifteen, with lon g retrograde screws; and four, with cement. Results: The median period of survival was nine months. Patients with visce ral metastases had a median period of survival of three months compared wit h twelve months for patients without visceral metastases (p < 0.001). Patie nts with breast cancer presented later in the disease process (p < 0.004) a nd lived longer than did those with other carcinomas (p < 0.004), Forty-fiv e patients were evaluated three months after reconstruction, Thirty-four (7 6 percent) of them had relief of pain as determined by decreased use of nar cotics. Nine of the eighteen patients who could not walk preoperatively reg ained the ability to walk. Fourteen of the seventeen patients who originall y were able to walk in the community retained that ability. Thirty-three pa tients were available for evaluation at six months. Twenty-five (76 percent ) still had relief of pain, and nineteen (58 percent) were able to walk and function in the community. Overall, fourteen (25 percent) of the fifty-fiv e patients had moderate local progression of the disease, and five of these patients had failure of the fixation, Fourteen early complications develop ed in twelve (22 percent) of the patients. One patient (2 percent) died per ioperatively, Conclusions: Patients who have acetabular metastases that are refractory to radiation and chemotherapy have a short life expectancy. The early, gratif ying results of reconstruction validate the role of operative treatment as a short-term palliative procedure, Protrusio acetabular cups presumably com pensate for deficiencies of the medial wall, while cement and pin fixation can be used effectively to reconstruct large defects in the acetabular colu mn and dome. The low rate of fixation failure supports the biomechanical pr inciples of the reconstruction. Generally, the reconstructions are sufficie ntly durable to exceed the life expectancy of the patients.