Adjustable stemmed shoulder hemiarthroplasty: Ten-year results of a prospective multicentre study.

BACKGROUND: Adjustable shoulder hemiarthroplasty (HA) allows the complex anatomy of the proximal humerus, including its centre of rotation, to be restored. However, whether better anatomical adaptation improves clinical outcomes and long-term survival remains unclear. Therefore long-term clinical and radiographic results of an eccentric adjustable hemiprosthesis were examined, focusing on the longevity and fixation of the humeral stem. HYPOTHESIS: Adjustable shoulder HA enhances long-term functional outcomes and reduces complications. MATERIALS AND METHODS: In this prospective multicentre study, 120 HAs were performed using a stemmed hemiprosthesis on 115 patients. The clinical and radiologic outcomes were measured at 3, 6, 12, and 24 months, and thereafter at 4, 7, and 10 years with a median follow-up period of 7.7 years (92.3 months, range 2.6-148.5 months). Revision-free survival rates were calculated up to 10 years postoperatively. RESULTS: The mean Constant-Murley score increased over the first 24 months from 26.2±9.0 to 61.0±17.3 points, then levelled off until the final follow-up. Patients with humeral head necrosis had the best clinical outcomes, while patients with fracture sequelae and rheumatoid arthritis had the worst. Although radiolucent lines were more frequent after cemented fixation, lines of>2mm only occurred after uncemented fixation. Finally, five cases required secondary glenoid implantation, and survival free from stem revision was 99.0% (95% confidence interval [CI], 92.8%-99.9%) at 4 years, 97.6 (95% CI, 90.6%-99.4%) at 7 years, and 92.2% (95% CI, 81.9%-96.8%) at 10 years. DISCUSSION: The study showed that adjustable shoulder HA is a safe and effective treatment option for various degenerative disorders of the shoulder joint. Functional scores first increased, then levelled off after 24 months. Moreover, revision-free survival compared well with previously reported values. Observed stable long-term results confirm that adjustable shoulder HA has beneficial clinical outcomes and a low complication rate.

Variability of medial and posterior offset in patients with fourth-generation stemmed shoulder arthroplasty.

PURPOSE: Most anthropometric data on the proximal humerus has been obtained from deceased healthy individuals with no deformities. Endoprostheses are implanted for primary and secondary osteoarthritis, rheumatoid arthritis,humeral-head necrosis, fracture sequelae and other humeral-head deformities. This indicates that pathologicoanatomical variability may be greater than previously assumed. We therefore investigated a group of patients with typical shoulder replacement diagnoses, including posttraumatic and rheumatic deformities. MATERIAL AND METHODS: One hundred and twenty-two patients with a double eccentrically adjustable shaft endoprosthesis served as a specific dimension gauge to determine in vivo the individual humeral-head rotation centres from the position of the adjustable prosthesis taper and the eccentric head. RESULTS: All prosthesis heads were positioned eccentrically.The entire adjustment range of the prosthesis of 12 mm medial/lateral and 6 mm dorsal/ventral was required. Mean values for effective offset were 5.84 mm mediolaterally[standard deviation (SD) 1.95, minimum +2, maximum +11]and 1.71 mm anteroposteriorly (SD 1.71, minimum −3,maximum 3 mm), averaging 5.16 mm (SD 1.76, minimum +2,maximum + 10). The posterior offset averaged 1.85 mm(SD 1.85, minimum −1, maximum + 6 mm). CONCLUSIONS: In summary, variability of the combined medial and dorsal offset of the humeral-head rotational centre determined in patients with typical underlying diagnoses in shoulder replacement was not greater than that recorded in the literature for healthy deceased patients.The range of deviation is substantial and shows the need for an adjustable prosthetic system.

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.

Anatomic and reverse shoulder prostheses in fracture sequelae of the humeral head.

OBJECTIVES: Arthroplasty for the proximal humerus problems secondary to fractures is troublesome, because of necrosis of the tubercles and the resulting insufficiency of the rotator cuff. The aim of this study was to investigate whether better results can be achieved with the differential use of anatomic and reverse shoulder prostheses, in comparison to the preoperative status. METHODS: Fifty-five patients with secondary fracture prostheses due to sequelae of fractures of the humeral head were followed. Anatomic prostheses were implanted in 36 cases (fracture sequelae types 1 and 2 according to Boileau), and reversed prostheses were implanted in 19 cases (fracture sequelae types 3 and 4). RESULTS: The mean scores of the patients improved from 19 to 68 points (anatomic prosthesis) for fracture sequelae types 1 and 2, and from 9 to 47.5 points (reverse prosthesis) for fracture sequelae types 3 and 4. CONCLUSION: The differential use of anatomic and reversed shoulder prostheses in secondary fracture treatment leads to an improvement in postoperative results. In fracture sequelae types 1 and 2, the anatomic prosthesis is a better choice. However, in fracture sequelae types 3 and 4 with severe deformities, the reversed prosthesis is clearly superior to the anatomic prosthesis.