Megaprosthesis versus Allograft Prosthesis Composite for massive skeletal defects

Abstract

Massive skeletal defects are encountered in the setting of tumors necessitating excision, failed total hip arthroplasty with periprosthetic bone loss, periprosthetic fracture, complex trauma, multiple failed osteosynthesis and infection. Reconstruction of the segmental defects poses a tremendous challenge to the orthopaedic surgeons. The goal of osseous reconstruction of these defects is to restore the bone length and function. Currently the most commonly employed methods for reconstruction are either a megaprosthesis or an Allograft Prosthesis Composite (APC). Megaprosthesis, initially created for the treatment in neoplastic pathologies are being used for the non-neoplastic pathologies as well. The longevity of these implants is an issue as majority of the patients receiving them are the survivors of oncologic issue or elderly population, both in which the life expectancy is limited. However, the early complications like instability, infection, prosthetic breakage and fixation failure have been extensively reported in several literatures. Moreover, the megaprostheses are non-biological options preventing secure fixation of the soft tissue around the implant. The Allograft Prosthesis Composites were introduced to overcome the complications of megaprosthesis. APC is made of a revision-type prosthesis cemented into the skeletal allograft to which the remaining soft tissue sleeve can be biologically fixed. APCs are preferred in young and low risk patients. Though the incidence of instability is relatively low with the composites as compared to the megaprosthesis, apart from infection, the newer complications pertaining to APCs are inevitable that includes non-union, allograft resorption, periprosthetic fracture and potential risk of disease transmission. The current review aims to give an overview on the treatment outcomes, complications and survival of both the megaprostheses and APCs at different anatomic sites in both the upper and lower limbs.

Clinical outcome of various limb salvage surgeries in osteosarcoma around knee: Megaprosthesis, extracorporeal irradiation and resection arthrodesis

“…In developed countries, because of the accessibility and ease of insertion, megaprosthesis are commonly being used. The megaprostheses of for early mobility with the maintenance of joint motion in these cases [20].…”

“…These reconstructions were also insufficient due to the lack of muscle strength and subsequent instability of the adjoining joint leading to impaired function. On the other hand, infection and loosening have remained as the main issues following reconstruction with the megaprosthesis [20].…”

Pedicle frozen autograft-prosthesis composite reconstructions for malignant bone tumors of the proximal femur

“…3d). Given that biological reconstructions can achieve acceptable long-term functional outcome, biological reconstructions have received increasing attention [10].…”

Complications following allograft reconstruction for primary bone tumors: Considerations for management

“…The implementation of allografts in limb salvage procedures allows for the preservation of osseous structures following massive resection with comparable functional outcomes to endoprosthetic reconstruction. [1][2][3][4][5][6][7][8]42,44 Despite the benefits surrounding allograft reconstruction, complication rates such as infection, fracture, and non-union are widely reported. 31,32 Postoperative rates of infection have been reported to range from 0 to 57.8% in the literature (Table 3).…”