The Popliteal Keystone Island Flap for Management of Contracture around Knee Joint: A Report of Two Cases.

Introduction: Flexion contracture affecting the knee joint is considered a challenging obstacle which usually affects patients' quality of life with significant functional disability. Several surgical procedures have been described for proper closure of surgical defects following contracture release over popliteal fossa. Although keystone flap reported for closure of full thickness burns defects, to our knowledge, it has never been used previously in management of hypertrophic scar contracture around the knee joint. We are presenting a two-case report with contracture hypertrophic scar over popliteal fossa where the keystone flaps were used to cover the soft tissue defects following excision of the scar contracture.

Case presentation: After excision of contracture scar, the length and width of the defect were measured. Then, the keystone flap design was marked over popliteal fossa where the width of the flap was equal to twice times the width of the defect. The flap length depends upon the length of elliptical excision which could changes after release of the contracture scar. After contracture release, skin incision was made along the marked flap border and then deepened till deep fascia which was divided as well along the flap border. Undermining the flap should not be performed to avoid perforator injury. During closure, the first suture was done at the center of the flap where experiencing maximum tension while the remaining part of the flap was properly sutured to the defect.

Conclusion: The popliteal keystone perforator flap can be a reliable method for correction of contracture scar over the popliteal fossa with relatively low complication or recurrence rates on long-term follow up.