Allograft Reconstruction of the Extensor Mechanism afterResection of Soft Tissue Sarcoma

Soft tissue tumors around the knee joint still pose problems for the excision and subsequent reconstruction.Methods.In the 6 included patients the soft tissue sarcoma has its base on the anterior surface of the extensor mechanism and expands towardsthe skin. The entire extensor apparatus (quadriceps tendon, patella, and patellar tendon) was resected and replaced by a fresh-frozenallograft.Results. The mean follow-up was 6.7 years (range: 2–12.4 years). In two patients a local recurrence occurred, resulting in a5-year local recurrence-free rate of 66.7% (95% CI:19.5%–90.4%). Distant metastases were found in 4 patients resulting in a 5-yearmetastasis-free rate of 33.3% (95% CI:4.6%–67.5%). Two patients underwent at least one revision surgery, including one patientin whom the allograft had to be removed. According to the ISOLS function score 24.7 points (range: 19–28 points) were achievedatthelastfollow-up.Themeanactiveflexionofthekneejointwas82.5∘(range: 25–120∘)andameanextensionlagof10∘(range:0–30∘)wasobserved.Conclusions. The replacement of the extensor mechanism by an allograft is a reasonable option, allowing widemargins and restoration of active extension in most patients.Trial Registration. The presented study is listed on the ISRCTN registrywith trial number ISRCTN63060594.