The impact of preoperative bone mineral density on outcomes following lower extremity megaprosthetic reconstruction for oncologic resections.

BACKGROUND: While megaprosthetic reconstructions have been instrumental in restoring patients' functional abilities, surgeons remain cautious of revision risk. This is the first study to assess the impacts of preoperative bone mineral density (BMD) on outcomes following lower extremity megaprosthetic reconstructions. METHODS: This was a retrospective cohort study of patients who underwent lower extremity oncologic megaprosthetic reconstruction between March 2005 and January 2022. Hounsfield units of the first lumbar vertebrae within a year prior to surgery were blindly collected for assessment of BMD. Patient demographics, megaprostheses characteristics and postoperative outcomes were recorded. Primary outcomes were complications according to the Henderson classification and implant survival rate. RESULTS: Eighty-four patients underwent a lower extremity megaprosthetic reconstruction. Mean age was 46.6 ± 22.5 years and average follow-up was 53.5 ± 52.9 months. Indication for surgery included primary bone tumor (81.3 %) and secondary bone tumor (18.8 %). Twenty-three patients (28.8 %) had low BMD. The rate of revision was 27.5 % in the total cohort and not significantly different between groups. The most common indication for revision was infection. While no patients with low BMD developed aseptic loosing or structural failure, they were more likely to receive femoral cement fixation (OR = 5.7; 95 %CI = 1.2,55.6). Five-year implant survivorship was 66.6 % (95 %CI [54.9 %- 80.8 %]). CONCLUSION: There was no significant difference in revision rate following oncologic lower extremity megaprosthetic reconstruction in patients with or without low BMD. No patients with low BMD in this cohort experienced aseptic loosening or structural failure; however, there was a bias toward cement fixation in patients with low BMD. This may reflect calculated decisions by the surgeon when evaluating the patient's bone quality and their specific risk profile. Our findings suggest that patients with low BMD have similar outcomes to patients without low BMD undergoing oncologic megaprosthetic reconstructions by experienced surgeons. The specific effect of cemented vs uncemented fixation in patients with low BMD in the oncologic population deserves further investigation.

Duke Scholars

Author Roy John Colglazier Radiology, Musculoskeletal Imaging

Author William Curtis Eward Orthopaedic Surgery

Author Brian Eugene Brigman Orthopaedic Surgery

Author Julia Dawn Visgauss Orthopaedic Surgery