In Situ Microwave Ablation With Intralesional Resection and Subsequent Mechanical Reinforcement for Juxtaarticular...

Joint-preserving surgery of a patient's native knee joint for juxtaarticular osteosarcoma may enhance function but poses resection and reconstruction challenges.

We included 15 patients with nonmetastatic distal femoral osteosarcoma who underwent in situ microwave ablation with intralesional resection and subsequent mechanical reinforcement. Knee function was assessed at 1 and 3 years postoperatively using Musculoskeletal Tumor Society scores, six degrees of freedom kinematic analysis. The 1-year and 3-year construct and overall survival rates were recorded. A control group of 20 healthy individuals was used for comparison.

At the 3-year follow-up, two patients had died. The final Musculoskeletal Tumor Society score was 29.0 ± 1.2 (range, 26 to 30). No major complication was recorded. At 1 year, notable gait differences were observed compared with healthy control subjects, including reduced knee flexion at 12%, 52%, 62%, 75%, and 85% of the gait cycle; increased adduction at 12%, 52%, 62%, and 75%; and increased external rotation at 52%, 62%, 75%, and 85%. The range of motion (ROM) in flexion/extension, internal/external rotation, proximal/distal translation, and medial/lateral translation (P < 0.05) were significantly reduced. At 3 years, most kinematic differences had diminished and ROM differences had largely resolved, with only an increase in internal/external and abduction-adduction ROM.

The surgical procedure of in situ microwave ablation with intralesional resection and subsequent mechanical reinforcement shows restricted mobility at 1 year postoperatively, but knee kinematic performance is nearly indistinguishable from that of healthy individuals at the 3-year follow-up. With adequate resection and adjuvant treatment insured, mechanical reinforcement reconstruction effectively preserves knee function.