Aims. The survival of humeral hemiarthroplasties in patients with relatively intact glenoid cartilage could theoretically be extended by minimizing the associated postoperative glenoid erosion. Ceramic has gained attention as an alternative to metal as a material for hemiarthroplasties because of its superior tribological properties. The aim of this study was to assess the in vitro wear performance of ceramic and metal humeral hemiarthroplasties on natural glenoids. Methods. Intact right cadaveric shoulders from donors aged between 50 and 65 years were assigned to a ceramic group (n = 8, four male cadavers) and a metal group (n = 9, four male cadavers). A dedicated shoulder wear simulator was used to simulate daily activity by replicating the relevant joint motion and loading profiles. During testing, the joint was kept lubricated with diluted calf serum at room temperature. Each test of wear was performed for 500,000 cycles at 1.2 Hz. At intervals of 125,000 cycles, micro-CT scans of each glenoid were taken to characterize and quantify glenoid wear by calculating the change in the thickness of its articular cartilage. Results. At the completion of the wear test, the total thickness of the cartilage had significantly decreased in both the ceramic and metal groups, by 27% (p = 0.019) and 29% (p = 0.008), respectively. However, the differences between the two were not significant (p = 0.606) and the patterns of wear in the specimens were unpredictable. No significant correlation was found between cartilage wear and various factors, including age, sex, the size of the humeral head, joint mismatch, the thickness of the native cartilage, and the surface
We assessed the clinical results, radiographic
outcomes and complications of patients undergoing total shoulder replacement
(TSR) for osteoarthritis with concurrent repair of a full-thickness
rotator cuff tear. Between 1996 and 2010, 45 of 932 patients (4.8%)
undergoing TSR for osteoarthritis underwent rotator cuff repair.
The final study group comprised 33 patients with a mean follow-up
of 4.7 years (3 months to 13 years). Tears were classified into small
(10), medium (14), large (9) or massive (0). On a scale of 1 to
5, pain decreased from a mean of 4.7 to 1.7 (p = <
0.0001), the
mean forward elevation improved from 99° to 139° (p = <
0.0001),
and the mean external rotation improved from 20° (0° to 75°) to
49° (20° to 80°) (p = <
0.0001). The improvement in elevation
was greater in those with a small tear (p = 0.03). Radiographic
evidence of instability developed in six patients with medium or
large tears, indicating lack of rotator cuff healing. In all, six
glenoid components, including one with instability, were radiologically
at risk of loosening. Complications were noted in five patients,
all with medium or large tears; four of these had symptomatic instability
and one sustained a late peri-prosthetic fracture. Four patients
(12%) required further surgery, three with instability and one with
a peri-prosthetic humeral fracture. Consideration should be given to performing rotator cuff repair
for stable shoulders during anatomical TSR, but reverse replacement
should be considered for older, less active patients with larger
tears. Cite this article:
