Comparison of stemless and conventional stemmed shoulder arthroplasties in shoulder arthropathy

摘要

Shoulderarthroplasty isa well-established treatment for severe osteoarthritis ofthe glenohumeraljoint to relieve pain and to restoreshoulder function. When along-stemhumeralcomponent is implemented,extensive boneingrowth or use ofacemented long-stemprosthesis makeit difficult to removethefixed components during revision shoulderarthroplasty. Moreover,as thetraditionalfixationmethod is difficult to apply in patients with degenerativechanges ofthe proximal humerus, these patients often requireadditional procedures such as osteotomy ofthe greater tuberosity ofthe proximal humerus. [1] After theinsertion ofthelong-stemprosthesis, variouscomplicationscould develop, including bone resorption around the proximal part ofthe bonecaused by stress shielding, [2–4] osteolysis dueto polyethyleneresidues,and periprosthetic fracture. [5,6] Periprosthetic humerus fracturesaccount forapproximately 20%ofallcomplicationsassociated with shoulderarthroplasty. [7–10] A short-stemhumeralcomponent was introduced to reducetherisk ofcomplicationscaused by thelong-stemprosthesis. [11–14] Thelong-stem prosthesis was designed to hold theimplant by applying pressureto the humeralshaft, whereas theshort-stemprosthesis was designed to hold the implant by compressing thecancellous bone ofthe proximalmetaphysis. Therefore, theshort-stemprosthesiscan reducethestress shielding ofthe proximal part ofthe humerus, unlikethelong-stemprosthesis. Most recently, stemless shoulderarthroplastywas newly introduced to minimizethe risk ofstem-associated complications by fixing the prosthesis on the metaphysis ofthe humeral neck. Stemless shoulderarthroplasty not only allows foran easier revision shoulderarthroplasty butalso provides further support for the maintenance ofthe bone quality ofthe proximal humerus. [15] However, thereareconcerns with stemless shoulder prosthesis; they cannot be used in cases with poor bone quality,especially in elderly patients,and therisk ofintraoperativefractures ofthe greater tuberosity by atight press-fitmetaphysealcentralanchor or screwfixation. [16] Althoughmany studies havereported theclinical outcomeand complication rates of patients who underwentshoulderarthroplastywith 1 ofthe 2 prosthesis, fewcomparativestudiesexist. This meta-analysis was performed to assessclinical outcomesand complication ratesafter surgery in patients with shoulderarthropathy treated with stemless orconventionalstemmed shoulder implants. The hypothesized is thatstemless shoulder implants would lead to betterclinical outcomesand lowercomplication rates than conventionalstemmed shoulder implants in patients with shoulder arthroplasty at finalfollow-up.