9–13 Year Results of Stemless Humeral Head Replacement. A Prospective Study

Abstract

The aim of the study was the evaluation of long-term results of shoulder arthroplasty using a stemless humeral head component. Since their introduction in 2005, the stemless humeral head prostheses have been established. Long-term functional and radiological results are not available until now. Since 2005 we documented stemless humeral head replacement prospectively. Eighty-seven patients with a mean age of 58 years at surgery (40 hemi-shoulder arthroplasties (HSA),47 total shoulder arthroplasties (TSA),46 female, 41 male) were clinically and radiologically followed-up after a mean of 128 months (range, 105-157 months).Functional results were documented using the age- and gender-normalized Constant score (rel. CS). The rel. CS improved significantly (p<0.0001) from 56 points (p) pre-op to 88p post-op. Its subcategories pain (8p pre-, 12p post-OP; p<0.0001), ADL (10p pre-OP, 15p post-OP; p<0.0001), ROM (20p pre-OP, 28p post-OP; p<0.0001) and strength (6p pre-OP, 11p post-OP; p=0.001) improved significantly as well. Results for HSA (mean follow-up 128 months):-Rel CS:57p pre-OP,90p post-OP; p<0.0001-CS pain:7.8p pre-OP,11.9p post-OP; p<0.0001-CS ADL:9.5p pre-OP,14.5p post-OP; p=0.001-CS ROM:19.8p pre-OP,27.5p post-OP; p=0.001-CS strength:6p pre-OP,12.2p post-OP; p=0.01 Results for TSA (mean follow-up 128 months):-Rel CS:55p pre-OP,87p post-OP; p=0.001-CS pain:7.9p pre-OP,12.4p post-OP; p=0.003-CS ADL:10.4p pre-OP,14.8p post-OP; p=0.014-CS ROM:19.5p pre-OP,28.9p post-OP; p=0.001-CS strength:6.1p pre-OP,9.8p post-OP; p=0.033 There is no significant (p>0.05) difference of pre- and post-op CS as well as its subcategories between HSA and TSA. Radiologically we observed no loosening of the stemless humeral head component. An incomplete radiolucent line of the humeral component was found in 7.9%.Stress shielding around the humeral component was not detected. Upward migration of the humeral head was observed in 23% (23.7% HSA, 15% TSA; p=0.334).No implant failure was observed at the humeral side. One humeral head replacement was explanted 7 months post-op because of early infection. 18.4% had a rotator-cuff deficiency at follow-up (HSA: 7.5%,TSA 27.7%;p=0.039).Overall,12.6% of stemless shoulder arthroplasties were revised to reverse total shoulder arthroplasty (5% of HSA,19.1% of TSA).8.5% of TSA required an anatomic glenoid replacement. TSA had significantly (p=0.014) more frequently revision surgery than HSA. Stemless humeral head replacement showed no loosening with a significant improvement of shoulder function after a mean of 11 years. There is no difference of functional results between HSA and TSA.TSA showed a significant higher revision rate than HSA.