Long-term results of the uncemented resurfacing shoulder hemiarthroplasty (Global C.A.P.)
These authors sought to determine the long-term results of the Global C.A.P. uncemented resurfacing shoulder hemiarthroplasty (DePuy Synthes).
23 out of 48 patients (48%, (18 women and 5 men)) were available for the 10-year follow-up assessments and were used for analysis. The main reasons for drop out were revision (27%) and death (10%).
For the remaining patients the mean follow-up was 10.9 years. In these patients the clinical scores are shown below:
Pain was improved from visual analogue pain scale of 6.5 to 0.7,
The Dutch Simple Shoulder Test improved from 22 to 79.
The Constant Score improved from 40 to 70
The SF-12 physical scores improved from 36 to 41.
Thirteen (27%) of the initial 48 patients underwent revision surgery. Most revisions were seen within 7 years postoperatively.
Erosion of the glenoid was present in 17 shoulders (74%) at long-term follow-up. A right shoulder with progressive glenoid erosion and medialisation of the humeral head 10 years after resurfacing hemiarthroplasty is shown below
The authors concluded that the high overall revision rate of 27% suggests the need to limit the use of this implant for treatment of glenohumeral osteoarthritis.
Comment: This study points to the challenge and importance of long term followup of any type of shoulder arthroplasty. While <50% of the initial group were available for 10 year followup, the revision rate for those available was 27%.
A number of questions were not answered about this study: (1) what was the relationship between the amount of glenoid erosion and the clinical outcome? (2) how did the preoperative characteristics of the patient (age, sex, comorbidities) and the shoulder (cuff status, retroversion, glenoid type) compare for the revised and unrevised arthroplasties?
While it preserves more humeral bone than other types of shoulder arthroplasty, the resurfacing implant does not address the glenoid side of the arthritic glenohumeral joint. The large amount of retained proximal humerus is likely to interfere with access to the glenoid should a glenoid arthroplasty be attempted.
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