Free flap reconstruction of the knee: an outcome study of 34 cases

Open wounds around the knee joint can often be managed with local flaps; however, free tissue transfer may be required when local tissue options are unavailable or inadequate. Free tissue transfer around the knee can be challenging due to unique anatomic features of the joint. The outcomes of such procedures remain largely unreported.

We retrospectively analyzed 33 patients who underwent 34 free tissue transfer reconstructions to the knee from 1993 to 2010. Twenty-four flaps were composed of soft tissue only and 10 flaps included a bony component. Patient demographics, details of the defect, operative characteristics, and clinical outcomes were reviewed. Outcomes included rates of flap failure, flap reexploration, and limb salvage.

Thirty-three (97%) of 34 flaps survived. One flap failed secondary to arterial thrombosis. In total, 6/34 flaps (18%) required reexploration (2 arterial thromboses and 4 venous thromboses). A wide variety of donor and recipient vessels were used. Vessel selection did not affect vascular reexploration. Overall, 88% of lower extremities were salvaged. Four of 10 (40%) patients receiving bone free flap reconstruction experienced delayed union and 2 (20%) of these required amputation for eventual nonunion.

Free flap reconstruction of the knee has a high flap survival and limb preservation rate in threatened extremities. Flap survival rates in the knee are similar to reported rates elsewhere in the lower extremity. Despite flap survival, infected nonunions that occur after bone free flap reconstruction result in a high limb amputation rate.