Clinical and radiographic findings in bilateral total shoulder arthroplasty

We hypothesized that the clinical and functional results as well as the absence or presence of radiolucent lines may be more affected by patient-related (internal) factors than by nonpatient-related factors (external factors). To test this hypothesis, we compared the clinical and radiological results of patients who underwent bilateral total shoulder arthroplasty in an individual matched-pair analysis.

We evaluated 47 patients who underwent two-staged bilateral primary shoulder arthroplasty with a cemented glenoid component. The Constant score as well as radiography in two plains were examined before surgery and at most recent follow-up.

The mean Constant score for all shoulders increased from 24 (range 0–55) points to 64.8 (range 10–84) points at a mean of 46.4 (range 24–178) months. There was no significant difference for the clinical outcome, range of motion, radiolucent lines, or tilting of the glenoid component between the two sides of the body. A significant difference was found for superior subluxation with higher results for the first arthroplasty. We found in 92 % of all cases radiolucent lines grade 2 or higher according to Franklin and in 23 % moderate or severe superior subluxation. These radiographic findings develop constantly over time. Superior subluxation and tilting of the glenoid component influenced the postoperative Constant score (p = 0.010; p = 0.044), while radiolucent lines had no impact on clinical outcome (p = 0.798).

Primary staged bilateral TSA can provide good results in patients with osteoarthritis of the shoulder. Our findings demonstrated that internal factors as well as external factors influence the clinical and radiological results in TSA.