Should Zoledronic Acid Loaded Bone Cement Be Used in Major Acetabular Reconstruction of Pathological Fractures?

Introduction: Symptomatic bone metastases of the acetabulum have detrimental effects on patients’ quality of life. Acetabular cages, cement and Harrington screws are commonly used for complex acetabular reconstruction with a complication rate of up to 31% including loosening and local recurrence. Little is known of the local effect of zoledronic acid in this setting. We present a case series of acetabular reconstruction using zoledronic acid loaded bone cement.

Methods: A Retrospective chart review of all patients having complex acetabular reconstruction at a single institution from 10.2009 to 3.2017 was conducted. Patients demographic, histology, reconstruction technique, mobility and pain medications were collected.

Results: 20 patients (11 females) with 21 lesions were identified. Mean age at surgery was 60 years with mean follow up of 12 months. 13 patients were alive at last follow up. Breast (n=7) and lung (n=6) were the most common histology. All lesions had surgery for an actual (n=14) or impending (n=7) fracture. Lesions were classified as Type 1 (n=8), 2 (n=5), 3 (n=6) and 4 (n=2) according to the Harrington classification. Zoledronic acid loaded bone cement was used in all patients. All patients were ambulatory post operatively including 5 who were non ambulatory prior to the surgery (p=0.06). 95% of patients required the use of pain medications pre operatively with only 57% using pain medication within 45 days post operatively (p=0.125). There were 5 major complications: 1 death post operatively from fat emboli, 2 dislocations treated with closed reduction and 2 revisions for protruding pin and periprosthetic fracture, respectively.

Discussion: Complex hip reconstruction for acetabular lesions improves mobility and pain. It out lives the patient’s life expectancy. No loosening or local recurrence of tumor was seen. Zoledronic acid loaded bone cement may prevent implant loosening or local recurrence of tumor in the setting of complex acetabular reconstructions.