[Flap coverage of soft tissue defects after total knee arthroplasty]

Due to the marginal periarticular soft tissue envelope and the high risk of concomitant soft tissue or periprosthetic infection with the presence of exposed metal or bone, soft tissue defects after total knee arthroplasty are always a relevant surgical problem. Specific patient-related, intra- and postoperative risk factors have been identified and need to be considered during the course of treatment. Often a profound management of underlying infection must accompany the staged defect treatment which could require a prosthesis explantation with secondary revision in the case of a deep infection and involvement of the prosthesis. Four stages of soft tissue defects have been introduced (types A-D) and criteria for differentiation are the overall soft tissue coverage, the exposure, respectively, necrosis of the extensor mechanism, preservation or involvement of the joint capsule and/or an accompanying septic loosening of the prosthesis. The concept of plastic coverage follows a stage-adapted algorithm and includes secondary wound healing and mesh coverage for superficial defects, fasciocutaneous flaps for moderate defects and pedicled or free muscle flaps for deep defect situations with extension into the joint capsule. Crucial factors for a successful therapy include the early identification and precise analysis of defect characteristics, the careful preparation of the wound bed with serial debridements and the diligent flap coverage with early consultation of plastic-surgical expertise.