Modified politeo-posterior thigh flap for chronic ulcer of the knee - Case reports

Soft tissue defects over the knee joint can be a troublesome problem. The upper part of the anterior aspect of the knee is a particularly difficult area because the adjacent skin and muscles often have been damaged at the same time. Here, we present cases of two patients who with soft tissue defects over the knee, which were reconstructed with a modified popliteo- posterior thigh flap. The flap was based on a perforator from the popliteal artery, which lay in the upper part of the popliteal fossa and ascended in the midline between semitendinosus and biceps femolis. The flap was augmented with the dermis around the vascular pedicle, and was transposed distally to cover the defect. The preserved dermis pedicle could increase venous drainage, thus promoting circulation in the flap. This improvement might come from microvenous interconnections between the venae comitantes and venules in the subcutaneous tissue and it could prevent venous congestion, which would have occurred because of flow characteristics of the reverse flap. One case suffered from repeated trauma over the knee and the other had chronic osteomyelitis following total knee replacement with resultant infection. The flap survived well and the donor site wound healed by skin graft. This flap is a easy method for reconstruction of chronic wounds around the knee. It preserves surrounding muscle function because it does not sacrifice muscle function, as does a musculocutaneous flap. In addition, the donor site wound is hidden on the posterior thigh and is less conspicuous. There is also discussion of myocutaneous flaps and fasciocutaneous flaps for knee reconstruction.