Proximal Humeral reconstruction in patients withmassive bone loss is a challenging procedure due to difficulties inreconstruction of large skeletal defects, replacing the low quality bone(1), maintaining post-operative component fixation and prosthetic stability(2). Disruption of rotator cuff attachment and strippingof surrounding soft tissue coupled with alteration of the deltoid tension dueto changes in humeral length make reconstructive surgery technically demandingin order to restore shoulder functions(3). Custom-made endoprosthetic replacement was firstintroduced in 1943 for proximal femoral reconstruction after wide excision ofgiant cell tumour in USA (4).
The use of these implants was limited until lateseventies when it became the gold standard technique after excision ofosteosarcoma due to advances of chemotherapy protocols and development in new diagnosticimaging techniques(5, 6). This allows orthopaedic oncologists to preciselyassess tumours extension within the bone and surrounding soft tissues(6). The wide use of endoprosthesis for reconstructionafter bone sarcomas excision helped the development of the modular systems thatenable surgeons to choose the optimum implant size for each patient(5). Modular Endoprosthetic replacement (MEPR) was implantedto provide a satisfactory solution inlimb salvage procedure after a wide excision of bone sarcomas, metastaticlesions and aggressive benign bone tumours e.g., giant cell tumours with thesurrounding soft tissues when amputation was the only acceptable option(7).
O’Connor et al. emphasised that limb salvage isstill emotionally preferred by the vast majority of patients despite the factthere is an obvious reduction of limb functions compared to movements beforesurgery(8). MEPR has recently become an option forreconstruction after failed revision arthroplasties(9). The rates ofshoulder arthroplasty has risen dramatically throughout the last few decadesreaching approximately 2500 in the UK annually(10). Cofield R.reported that 88% of the performed arthroplasties have survival rate of 10years; consequently, the frequency of revision surgeries is expected toincrease (11, 12). Bone lossafter failed arthroplasty can result from boneresection in prosthetic infection, aseptic loosening, after removal of awell-fixed prosthesis and peri-prosthetic fractures(13). Few studies in the literature are available aboutthe results of MEPR in revision arthroplasty as many orthopaedic surgeonsprefer to use other common techniques for reconstruction such as allograft andleave MEPR as a last option(1).
Indications for MEPR have been also expanded toinclude patients with post resection osteomyelitis and highly comminuted poorly vascularizedfractures particularly for elderly osteoporotic populations when non-union ishighly unexpected (1). Wirganowicz et al. classified modes of failure afterMEPR into mechanical and non-mechanical factors. Mechanical failure which tracethe abnormal relationship between prosthesis and surrounding bone and softtissue such as, aseptic loosening, periprosthetic fatigue fracture and failureof bony supporting structure.
Despitethe fact that non-mechanical (biological) factors such as infection requiresimplant removal or revision, it does not violate normal relationship betweenprosthesis and surrounding tissues (14, 15). The majority of literature focuses on oncology limbsalvage survival and only a few reports the functional outcomes after proximalhumeral reconstruction.The aim of this study is to review the underlying pathologyfor massive proximal humeral bone loss, analyse the degree of pain reliefpostoperative and reportclinical and functional outcomes and to review complications associated withthese types of prostheses.