Medial Gastrocnemius Flap in the Course of Treatment for an Infection at the Site of a Total Knee Arthroplasty.

INTRODUCTION: The pedicled medial gastrocnemius flap provides a robust coverage option for most soft-tissue deficiencies over the distal anterior aspect of the knee encountered in the setting of an infection after total knee arthroplasty. STEP 1 PATIENT POSITIONING: Position the patient supine with an ipsilateral sterile thigh tourniquet to allow room for harvest of a split-thickness skin graft as needed. STEP 2 REVISION ARTHROPLASTY FOR INFECTION: Perform the arthroplasty to address the underlying deep infection (e.g., irrigation and debridement with exchange of modular components, component removal with antibiotic spacer placement, antibiotic spacer exchange, or second-stage reimplantation) prior to the medial gastrocnemius flap that is utilized for soft-tissue coverage. STEP 3 INCISION AND APPROACH FOR THE MEDIAL GASTROCNEMIUS FLAP: Use one of two different surgical approaches for the exposure and elevation of the medial gastrocnemius muscle and the identification of its vascular pedicle: the medial approach or the posterior midline approach. STEP 4 ELEVATION OF THE MEDIAL GASTROCNEMIUS FLAP: Protect the sural artery pedicle in the popliteal fossa because it is key to raising a viable medial gastrocnemius flap. STEP 5 TRANSPOSITION AND INSETTING OF THE FLAP OVER THE DEFECT: Rotate the flap and transpose it anteriorly over the defect either through a subcutaneous tunnel or by dividing the intervening skin bridge. STEP 6 CLOSURE SKIN-GRAFTING AND DRESSING APPLICATION: Complete the layered skin closure and place a split-thickness skin graft over the remaining exposed muscle flap and a nonadherent compressive bolster dressing or negative-pressure device over the skin graft to prevent hematoma under the skin graft. STEP 7 POSTOPERATIVE CARE: Progress range of motion of the knee once the flap and graft show evidence of survival, while an appropriate antibiotic regimen is completed.
RESULTS: We recently reported the largest English-language series, to our knowledge, of medial gastrocnemius flaps performed for soft-tissue coverage in the course of treatment for infection after total knee arthroplasty13.