The use of megaprostheses for reconstruction of large skeletal defects in the extremities: a critical review

Abstract

In the case of primary malignant tumors, extensive metastatic disease, major trauma or end-stage revision arthroplasty, the orthopaedic surgeon often has to deal with the need to reconstruct large skeletal defects, or replace bone of low quality. In the past years this was frequently impossible, and the only solution was amputation of the extremity. Later, the introduction of custom-made endoprostheses capable of reconstructing large skeletal defects, also known as megaprostheses, allowed for sparing of the extremity. This was especially valuable in the case of oncologic orthopaedic surgery, as advances in the medical treatment of sarcoma patients improved prognosis and limb-preserving surgery proved to have comparable patient survival rates to amputation. However, custom-made designs were implicated in frequent mechanical failures. Furthermore, they were extremely difficult to revise. The introduction of modular endoprostheses in the 1980s marked a new era in orthopaedic oncologic surgery. Modular megaprostheses consist of a number of different components in readily available sets, which can be assembled in various combinations to best address the specific bone defect. Moreover, they proved to have considerably lower rate of mechanical failures, which were also much easier to address during revision surgery by replacing only the parts that failed. The functional outcome after reconstruction with megasprostheses is often very satisfactory and the patient can enjoy a good quality of life. Nowadays, the major challenge is to eliminate the rate of non-mechanical complications associated with surgery of that magnitude, namely the risk for wound dehiscence and necrosis, deep infection, as well as local recurrence of the tumor. In our present mini-review, we attempt to make a critical approach of the available literature, focusing on the multiple aspects of reconstructive surgery using megaprostheses. We present the evolution of megasprosthetic implants, the indications for their use, and describe the outcome of surgery, so that the non-specialized orthopedic surgeon also becomes familiar with that kind of surgery which is usually performed in tertiary centers. A special interest lays in the recent developments that promise for even better results and fewer complications.

Keywords: Endoprosthetic reconstruction; megaprosthesis..

Fig. (1)

A case of reconstruction with a modular total humerus prosthesis (MUTARS) for an extensive destruction of the humerus with pathological fracture (left panel), and a case of proximal femur reconstruction using a modular METS prosthesis by Stanmore (right panel).