Prospective study of double-eccentric hemi shoulder arthroplasty in different aetiologies: midterm results

This prospective study aimed to analyse the effect of a newly developed double-eccentric adjustable stemmed prosthesis on reconstruction of the osseous anatomy, range of motion, strength and pain relief. A total of 91 consecutive hemiprostheses were evaluated preoperatively and three, six, 12, 24 and 48 months postoperatively (mean±SD 46.2 ± 10.9 months) by the American Shoulder and Elbow Surgeons (ASES) and Constant scores as well as radiological assessment. Clinical evaluations showed an increase in Constant score from 21.9 to 64.8 points and in ASES score from 24.9 to 77.9 points after two years. The results depend mainly on the underlying pathology. The best results were observed for primary osteoarthritis and avascular necrosis of the humeral head. All heads were eccentrically positioned. Specific stem-related complications were not observed. Because of the eccentric positioning of all heads it is reasonable to use adjustable shaft prostheses. The clinical results are comparable to data in the literature. Additional study provided a better or comparable clinical outcome and a low revision rate, when compared with other modern adjustable implants in the literature.