THE STANMORE EXPERIENCE OF CUSTOM-MADE CONSTRAINED SHOULDER PROSTHESES IN SALVAGE SURGERY

Abstract

Arthroplasty as a salvage procedure for cuff and glenoid deficiency poses major problems due to the limitations in treatment options and debilitating symptoms. We hypothesized that computer aided deigned and manufactured (CADCAM) total shoulder arthroplasty, using a precisely fitted glenoid shell, can relieve the pain and poor function associated with irreparable rotator cuff pathology and severe glenoid deficiency in the shoulder.

Of the 127 cases so far performed, a prospective cohort study 79 consecutive subjects, with a mean 28.7 month follow-up, were evaluated by a single practitioner blinded to their group status. Outcome was assessed using a validated clinical shoulder scoring system and radiographic review.

The subjects had a mean age of 58 (41–82) and their indication (where recorded) was mainly revision total shoulder replacement (62%) with some cases for primary osteoarthritis (12%) and rheumatoid arthritis (9%) and a proportion for other reasons (19%) including 1 re-revision case for dislocation.

Clinical follow-up was limited in this population (n=58, 73%) The ‘CADCAM’ group’s mean Stanmore Percentage of Normal Shoulder Assessment scores (SPONSA) were relatively unchanged post surgery (47 to 42 p=0.3). The Oxford Shoulder scores improved significantly (15 to 33, p< 0.0001). Most significantly, and by way of explanation, post surgery subjects recorded a reduction in the Visual Analogue Scale (Pain) scores (6.6 to 2.9) p< 0.0001). Patient satisfaction was generally good.

Radiographic review of the 79 cases revealed glenoid component screw breakage (4%, n=5) which is a moderate correlate of glenoid loosening (r = 0.65, r2 = 0.42) and probably more accurate than radiographic lucent lines seen in 6% (n=7). Humeral lucency was seen in 10%, (n=8). These radiographic findings correlated well with the clinical findings.

Postoperative pain and function was significantly improved in subjects undergoing the ‘CADCAM’ technique of shoulder arthroplasty offering a consistent salvage option for situations where no alternative to glenoid reconstruction is feasible.