A functional analysis of massive knee replacement after extra-articular resections of primary bone tumors.

We performed a functional analysis of massive knee replacements after extra-articular resection of primary bone tumors. Patients did not score as highly on the Musculoskeletal Tumour Society Score and Knee Society Score (P < or = .01) as patients who had undergone intra-articular resection. Lower scores were achieved for emotional acceptance (P < or = .01), functional restriction (P < or = .05), walking distance (P < or = .05), and managing stairs (P < or = .05). These patients had a significantly greater extension lag (P < or = .01) and greater fixed flexion (P < or = .05). This functional deficit is primarily due to a compromised extensor mechanism inherent in the type of surgical resection necessary to achieve adequate removal of the tumor.