Primary shoulder arthroplasty using a custom-made hip-inspired implant for the treatment of advanced glenohumeral arthritis in the presence of severe glenoid bone loss

Abstract

Background: Total shoulder arthroplasty for end-stage glenohumeral arthritis with severe glenoid bone loss poses a unique challenge for shoulder surgeons. Current surgical solutions are limited and associated with high complication rates. We hypothesized that a custom-made computer-aided design-computer-aided manufacturing (CAD-CAM) total shoulder replacement (TSR; Stanmore Implants Worldwide, Elstree, UK) resembling a total hip prosthesis could offer a reliable alternative for this challenging subset of patients.

Methods: Thirty-seven patients with rotator cuff-deficient end-stage glenohumeral arthritis and severe glenoid bone loss (assessed as not amenable to treatment with standard anatomic or reverse total shoulder implants) were treated with the CAD-CAM TSR between 2006 and 2013. Clinical data were collected prospectively and analyzed at a mean follow-up of 5 years.

Results: Postoperatively, the pain level with activity decreased from 9.2 ± 1.7 to 2.4 ± 2.9 (P < .001). The Oxford Shoulder Score improved from 11 ± 8 points to 27 ± 11 points (P < .001), and the Subjective Shoulder Value (on a 0%-100% scale) improved from 23% ± 14% to 60% ± 24% (P < .001). Active forward elevation improved from 39° ± 23° to 63° ± 38° (P < .001), and external rotation improved from 6° ± 16° to 15° ± 17° (P = .001). Component revision was required in 6 of 37 patients (16%) (glenoid loosening in 1, humeral stem loosening in 3, periprosthetic fracture in 1, and prosthesis dislocation in 1).

Conclusion: The CAD-CAM TSR offers a reliable alternative for the treatment of end-stage glenohumeral arthritis with severe glenoid deficiency not amenable to standard anatomic or reverse total shoulder implants, with maintenance of significant pain relief and clinical-functional improvement at 5-year postoperative follow-up.

Keywords: CAD-CAM shoulder; Total shoulder arthroplasty; custom shoulder implant; glenoid bone loss; glenoid deficiency; hip-inspired shoulder replacement; rotator cuff arthropathy.