Reverse shoulder arthroplasty for type 1 sequelae of a fracture of the proximal humerus.

Aims: The aim of this study was to analyze the results of reverse shoulder arthroplasty (RSA) in patients with type 1 sequelae of a fracture of the proximal humerus in association with rotator cuff deficiency or severe stiffness of the shoulder. Patients and Methods: A total of 38 patients were included: 28 women and ten men. Their mean age at the time of arthroplasty was 73 years (54 to 91). Before the RSA, 18 patients had been treated with open reduction and internal fixation following a fracture. A total of 22 patients had a rotator cuff tear and 11 had severe stiffness of the shoulder with < 0° of external rotation. The mean follow-up was 4.3 years (1.5 to 10). The Constant score and the range of movement of the shoulder were recorded preoperatively and at final follow-up. Preoperatively, radiographs in two planes were performed, as well as CT or arthro-CT scans; radiographs were also performed at final follow-up. Results: The mean Constant score improved from 25 points (5 to 47) preoperatively to 57 points (15 to 81) postoperatively. The mean forward elevation of the shoulder increased from 73° (10° to 130°) preoperatively to 117° (15° to 170°) postoperatively. Previous surgery did not influence the outcome. Patients with rotator cuff tears had lower Constant scores than patients without (p = 0.037). Those with preoperative stiffness of the shoulder had lower postoperative external rotation compared with patients without stiffness (p = 0.046). There was no radiographic evidence of loosening. Three complications occurred, leading to revision surgery in two patients. In all, 17 patients rated their result as very good (45%), another 17 as good (45%), two as satisfactory (5%), and two as unsatisfactory (5%). Discussion: RSA is an effective form of treatment for patients with type 1 sequelae of a fracture of the proximal humerus associated with rotator cuff deficiency or stiffness of the shoulder, with high rates of satisfaction. Rotator cuff tears and stiffness of the shoulder had an adverse effect on the clinical outcome. Cite this article: Bone Joint J 2018;100-B:318-23.

Shoulder hemiarthroplasty: outcomes and long-term survival analysis according to etiology.

BACKGROUND: The indications for hemiarthroplasty in glenohumeral joint diseases remain controversial and depend mainly on the original underlying diagnosis. Our objective was to investigate the influence of the primitive aetiology on long-term prosthesis survival and on the Constant-Murley score. MATERIALS AND METHODS: We studied 272 shoulders with the following diagnoses: fracture sequelae (n=73), primary osteoarthritis (n=67), cuff tear arthropathy (n=43), avascular necrosis (n=40), rheumatoid arthritis (n=31), and other (n=18). Of the 272 shoulders, 139 were evaluated after at least 8 years (mean follow-up, 134 months). In all, 30 prostheses required removal. Functional status was evaluated using the Constant-Murley score and survival rate using the Kaplan-Meier method with prosthesis removal or conversion to total arthroplasty as the endpoint. RESULTS: Ten-year prosthesis survival was 88.13% overall, 100% in the rheumatoid arthritis group, 94.9% in the avascular necrosis group, 94.2% in the primary osteoarthritis group, 81.5% in the cuff tear arthropathy group, and 76.8% in the fracture sequelae (P=0.05). The mean Constant-Murley score after 8 years or more was 70.1 in avascular necrosis, 60.7 in primary osteoarthritis, 57.7 in fracture sequelae, 55.3 in rheumatoid arthritis, and 46.2 in cuff tear arthropathy (P=0.0006). The complication rate with the initial population as the denominator was 24.7% in fracture sequelae, 18.6% in cuff tear arthropathy, 15% in avascular necrosis, 8.9% in primary osteoarthritis, and 3.2% in rheumatoid arthritis. CONCLUSIONS: The best indication for shoulder hemiarthroplasty is avascular necrosis and the worst indications are cuff tear and post-traumatic fracture sequellae. Rheumatoid arthritis and primary glenohumeral osteoarthritis are good indications in patients younger than 50 years of age. LEVEL OF EVIDENCE: Level IV, retrospective study.

Cement as a locking mechanism for screw heads in acetabular revision shells - a biomechanical analysis.

In acetabular revisions, polyethylene (PE) liners are often cemented into metal shells on top of acetabular screw heads. This study investigates the possibility of using this technique to obtain fixed-angle acetabular screws Eth a concept that has not yet been reported in the literature. Two groups of screws (n=8) were inserted into Trabecular Metal revision shells (Zimmer), into which PE liners were then cemented. Screws in Group 1, inserted in the shell's pre-fabricated holes, were countersunk, whereas screws in Group 2 were inserted in custom-drilled holes that make their heads protrude into, and interdigitate with, the overlying cement mantle. Perpendicular loading was then applied to the screw shafts both statically to failure and cyclically. A greater stiffness was observed for the protruding screws upon static loading; and while the countersunk screws all failed at the screw-cement junction (53.44 + or - 8.33 N), the protruding screws all failed at the screw shaft (1049.79 + or - 32.12 N) a 20-fold difference (p< 0.05). Under cyclic loading, only the protruding screw head specimen did not fail, undergoing an overall displacement within the limits of osseointegration.These results support the hypothesis that the protrusion of an acetabular screw head into an overlying cement mantle significantly increases its angular stability. Provided other variables are favorable, this locking effect may increase the initial stability of the whole implant, thus improving the ultimate success of complex acetabular revisions.