INTRODUCTION: Malignant tumors of the knee pose a significant challenge from both ablative and reconstructive standpoints. With the advent of microsurgery, improved prosthetic design and adjuvant treatment protocols, limb-sparing surgery has proven to be a safe and effective mode of treatment throughout many centers. Numerous authors have described their experience with extremity sarcomas but few studies focus on free tissue transfer as a means of providing coverage for defects of the knee following tumor ablation. The purpose of this study was to describe a single institution's experience with free flap reconstruction of the knee for oncologic defects.

METHODS: This was a retrospective review of patients reconstructed with free tissue transfer after limb sparing resection of malignant knee tumors. Patients were identified using a prospectively maintained database and a retrospective chart review was then performed. Between 1989 and 2005, 28 patients underwent free tissue transfer for coverage of knee defects. Among the data collected was patient age, tumor histology, immediate vs delayed reconstruction, use of endoprosthesis, allograft, autograft, type of free flap, recipient vessels, adjuvant treatment, post-operative mobility, and flap complications.

RESULTS: Of the 28 free tissue transfers, 19 were performed in a delayed fashion and 9 were for immediate reconstruction. The latissimus dorsi was used in 21 patients and the rectus abdominis in the remaining seven. 24 patients underwent some form of articular reconstruction (endoprosthesis, autograft and/or allograft). Of the 19 delayed reconstructions, ten were performed for infected and/or exposed prostheses. Adjuvant therapy was used in nineteen patients of which 14 received pre-operative chemotherapy. Seventeen patients achieved ambulation without assistance and an additional seven could ambulate with the aid of a cane or crutches. There were no complete flap failures. Five patients experienced partial flap loss (<10%). There were 3 wound infections. Induction chemotherapy did not predispose to infection. Twenty seven of twenty eight limbs were salvaged with only one patient requiring an above knee amputation for early tumor recurrence.

CONCLUSIONS: As treatment protocols evolve and life expectancy of sarcoma patients improves, limb preservation has become a significant component of extremity sarcoma treatment. The options afforded by microvascular surgery have enabled the orthopedic surgeon to undertake both complicated tumor extirpation and secondary revision-type procedures. Our series demonstrates that free flap reconstruction of the knee can have a high success rate with few complications and a high rate of ambulation.