Total shoulder arthroplasty with a metal-backed, bone-ingrowth glenoid component. Medium to long-term results.
BACKGROUND
Loosening of a cemented glenoid component is an important cause of failure in shoulder arthroplasty. This study was developed to examine the outcome of patients managed with a metal-backed, bone-ingrowth glenoid component as an alternative to a cemented component.


METHODS
The study group included eighty-three total shoulder arthroplasties with a metal-backed, bone-ingrowth glenoid component performed between 1989 and 1994. Seventy-four shoulders had a diagnosis of primary osteoarthritis, and nine shoulders had other diagnoses. All patients were followed radiographically and clinically for a minimum of two years or until the time of revision surgery. Kaplan-Meier survival estimates were performed with revision and/or radiographic failure as the end points.


RESULTS
The mean clinical follow-up was 9.5 years, and the mean radiographic follow-up was 7.1 years. Pain ratings (on a scale of 1 to 5) decreased from a mean of 4.7 preoperatively to 2.0 postoperatively. The mean range of motion in active elevation increased from 102 degrees preoperatively to 135 degrees postoperatively; the mean external rotation increased from 27 degrees to 56 degrees . Glenohumeral joint instability developed in fourteen shoulders. Radiographic changes consistent with glenoid component loosening were present in thirty-three shoulders. Polyethylene wear with metal wear of the glenoid component was noted in twenty-one shoulders, and humeral component loosening was seen in fifteen shoulders. Revision procedures were performed in twenty-six shoulders. There were no identifiable patient, disease, or surgical characteristics associated with failure, either clinically or radiographically. The five-year survival estimate free of revision or radiographic failure was 79.9% (95% confidence interval, 71.6% to 89.3%), and the ten-year survival estimate was 51.9% (95% confidence interval, 41.0% to 65.8%).


CONCLUSIONS
The high rate of failure of total shoulder arthroplasties performed with this metal-backed, bone-ingrowth glenoid component raises concerns as to its use, and perhaps the use of other types of metal-backed components, in shoulder arthroplasty, other than for special situations.


METHODS
Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.
Taunton
Michael J
MJ
Mayo Clinic, Rochester, MN 55905, USA.
McIntosh
Amy L
AL
Sperling
John W
JW
Cofield
Robert H
RH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D016348:Osseointegration; D011474:Prosthesis Design; D011859:Radiography; D012540:Scapula; D012785:Shoulder Joint; D013997:Time Factors; D016896:Treatment Outcome