Revision arthroplasty with a hip-inspired computer-assisted design/computer-assisted manufacturing implant for glenoid-deficient shoulders

Abstract

Background: Revision arthroplasty for failed post-traumatic humeral head replacement associated with rotator cuff and glenoid deficiency is challenging. Current surgical solutions are fraught with complications, and no best-practice strategy has been established. We hypothesized that the computer-assisted design/computer-assisted manufacturing (CAD/CAM) shoulder (Stanmore Implants, Elstree, UK), a total shoulder design resembling a total hip prosthesis, can offer a reliable alternative in this surgically challenging subset of patients with rotator cuff deficiency and advanced glenoid bone loss.

Methods: Twenty-one patients with failed post-traumatic humeral head replacement associated with rotator cuff and glenoid deficiency underwent revision with CAD/CAM shoulders between 2005 and 2010. Clinical data were collected prospectively and analyzed at a mean follow-up of 3 years.

Results: After revision, the pain rating at rest (on a 0-10 numerical scale) decreased from 5.6 ± 1.3 to 1.1 ± 1.3 (P < .001) and pain during activity decreased from 7.4 ± 1.2 to 2.1 ± 1.8 (P < .001). The Oxford shoulder score improved from 47 ± 6 to 31 ± 9 (P < .001), and the subjective shoulder value (on a 0%-100% scale) improved from 22% ± 14% to 45% ± 18% (P < .001). Active shoulder range of motion was similar before and after revision. Postoperative complications occurred in 9 patients and included 1 infection, 2 periprosthetic fractures, 2 prosthetic dislocations, and 4 fixation screw fractures. No case of glenoid loosening occurred.

Conclusion: The CAD/CAM shoulder offers a reliable method of securing a glenoid component in shoulders with advanced glenoid deficiency and should be considered as an alternative to other surgical methods in these challenging cases. At 3 years' follow-up, pain and clinical scores improved significantly and no case of glenoid loosening occurred.

Keywords: CAD/CAM; Case Series; Humeral head replacement; Level IV; Treatment Study; arthroplasty failure; custom implant; glenoid bone graft; glenoid deficiency; revision shoulder arthroplasty; shoulder hemiarthroplasty.