What sports activity levels are achieved in patients with modular tumor endoprostheses of osteosarcoma about the knee?

BACKGROUND: Advances in multimodal treatment have improved survival of patients with nonmetastatic osteosarcoma. At the same time, implant design has improved the outcomes of limb salvage with modular endoprostheses. However, little is known about sports activity in long-term survivors with osteosarcoma. QUESTIONS/PURPOSES: We wanted to evaluate (1) sports activity levels in long-term survivors of osteosarcoma about the knee who received a modular tumor endoprosthesis; (2) to determine if activity level changed over time from initial reconstruction or (3) was predicted from sports activity level before diagnosis; and (4) if complications that occurred affected sports or contributed to prosthetic failures.
METHODS: Between 1995 and 2005, we treated 120 patients for osteosarcoma about the knee with resection and modular endoprosthetic reconstruction; of those, 25 (21%) have died, six (5%) had an amputation, 39 (32%) did not speak German and so were ineligible, and 14 (12%) were either lost to followup or refused to participate, leaving 27 patients (14 females, 13 males; median age 19 years [range, 12-60 years); average followup 11 ± 4 years) (54% of the living, German-speaking cohort) for this analysis. Tumors were located in the distal femur (n = 16) and the proximal tibia (n = 11). Sports participation as well as the UCLA Activity Score and the modified Weighted Activity Score were assessed retrospectively. Moreover, postoperative complications were evaluated.
RESULTS: Before the diagnosis of osteosarcoma and 1, 3, and 5 years and at the latest followup, respectively, after their reconstructions, 24 (89%), nine (33%), 20 (74%), and 24 patients (89%) were able to perform sports activities. There was a reduction in high-impact activities. Those patients with followup longer than 5 years had no changes in sports activity at their latest followup. Patients who had higher levels of sports activity levels before surgery generally had higher levels of activity at last followup (UCLA Activity Score: r = 0.62, p < 0.0005; modified Weighted Activity Score r = 0.49, p < 0.01). Fourteen patients (51%) underwent revision surgery. With the numbers available, complications had no effect on sports activity. No sports activity-related complications were found.
CONCLUSIONS: Some long-term survivors of osteosarcoma can achieve high levels of sports activity. Preoperative activity levels seem to influence the postoperative activity levels. This information is important to give realistic expectations for long-term survivors of osteosarcoma of the knee. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.