Resurfacing shoulder arthroplasty is proposed in primary osteoarthritis of the shoulder. The present study compared resurfacing versus 3rd generation stemmed hemiarthroplasty in terms of survival, functional results and implant positioning effects.
Seventy eight patients underwent arthroplasty for primary osteoarthritis of the shoulder: 41 by resurfacing and 37 by stemmed hemiarthroplasty. The two populations were comparable on all baseline variables. Minimum follow-up was 2 years. The principal assessment criterion was survivorship with surgical revision as end-point. Secondary criteria were functional results on Constant, quick-DASH, Neer and SSV scores, and implant positioning effects assessed on radiology.
At a mean 44 months' follow-up (range, 24-118 months), there were no significant differences in functional scores. Radiologic analysis found greater varus positioning and lateral offset of the humeral head in resurfacing compared with stemmed hemiarthroplasty (128° vs 138°, P<0.01; 6.5 ± 2 vs 4.6 ± 1.6mm, P<0.01). Survivorship without revision was significantly poorer in resurfacing, with 4 revision procedures for glenoid wear (9.8%), versus none in hemiarthroplasty (P=0.02). There was no correlation between humeral head size, positioning or lateral offset and revision.
Level III; case-control study.
Revision-free survival was significantly lower in resurfacing than in hemiarthroplasty. Greater humeral head size may increase lateral offset, accelerating glenoid wear. Down-sizing the humeral head in resurfacing procedures might limit these complications.