Treatment of metastatic lesions localized in the acetabulum

BACKGROUND Metastatic lesions localized in the periacetabular area cause troublesome pain and reduced mobility of the patients. Radiotherapy effectively decreases pain, yet it does not restore the ability to load the joint. Surgical treatment involving resection of metastatic lesions and joint reconstruction using bone grafts is burdened with a high rate of complications. Modular tumor prostheses are being increasingly used. In some cases, it is possible to strengthen the acetabular roof with bone cement using vertebroplasty kits. The aim of the study was to demonstrate various methods of treatment of metastatic lesions localized in the periacetabular area together with the analysis of their results and effectiveness. METHODS Between 2010 and 2015, 27 patients with cancer metastases to the acetabulum were treated at our department. Qualification for surgical treatment was multifaceted with numerous aspects being considered. They included patients' general condition, type of neoplasm, clinical stage, and prognosis. CT and MRI scans of the pelvis were performed in each case. Before the surgery and 3 months following the surgery, visual analogue scale (VAS) pain intensity, Karnofsky functional status, and motor ability according to the Harris scale were evaluated. Bone cement (PMMA)-augmentation was performed in 21 patients, of whom nine had cement injected precutaneously and 12 at proximal femur resection alloplasty. Hemipelvectomy Type II combined with implantation of LUMiC resection prosthesis of the acetabulum were performed in six cases. RESULTS The quality of life improved in all the patients. After percutaneous cement injection, the mean pain intensity VAS score was 2.7, and the mean Karnofsky functional status score was 71.8. The mean postoperative Harris hip score (HHS) was 94 points. The patients who had undergone resection alloplasty on the proximal femur combined with periacetabular cement injection were walking using one crutch. In this group of patients, the mean postoperative pain intensity, functional status, and gait efficiency scores were 4.5, 65.7, and 82 points, respectively. The mean pain intensity VAS score in patients who had LUMiC prostheses implanted was 3.4. Their mean functional status score was 65 and the gait efficiency score 71 points. All the patients were able to walk on crutches. CONCLUSIONS Strengthening of the acetabular roof with bone cement in a specific group of patients is an adequate method of treatment which decreases pain and allows for loading the affected limb while walking. Internal hemipelvectomy combined with LUMiC prosthesis implantation makes it possible for the patients to walk using crutches and significantly reduces pain.