Abstract
Over the long term, the results of the insertion of a Grammont inverted shoulder prothesis are unknown. The present study reports survivorship curves and the role of the initial aetiology in patients re-examined after 5 to 10 years.
Patients and methods Eighty prostheses (for 77 patients) were implanted between 1992 and 1998: 66 cases of massive cuff tear arthropathy (MCTA) and 24 cases for another aetiology (mainly rheumatoid arthritis and revision).
At the time of follow-up, 18 patients had died and 2 could not be traced. The remaining patients (57 representing 60 prostheses) were seen by an independent examiner. The minimum follow-up was 5 years. The average follow-up was 69,6 months.
Kaplan-Meir survivorship curves for the 60 prostheses were established in order to show the probability of failure as defined by: revision of the prothesis, glenoid loosening, and a functional level< 30 points according to the Constant score.
Results The survivorship curves were as follow:
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- for non revision of the prosthesis at 10 years: 91% overall; after 9 years: 95% for MCTA, and 77 % for the others aetiologies. This difference was statistically significant (p< 0,01) ; 6 implants were revised: 3 for MCTA and 3 for other aetiologies.
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- for non glenoid loosening at 10 years: 84 % overall ; after 7 years: 91% for MCTA and 77% for other aetiologies. This difference was statistically significant (p< 0,05). In addition to the cases of replaced implants mentioned above there was a case of glenoid loosening after 8 years follow-up in a patient aged 92.
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-for Constant score < 30 at 10 years: 58 % overall. The punctual survivorship rate was significantly different in function of the aetiology, at 6 years ; but this was no longer the case after 7 years.
Discussion
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According to revision of the prosthesis, there is a clear rupture in the survivorship curve about 3 years after insertion in aetiologies other than MCTA. This suggests that Grammont inverted total shoulder arthroplasty is not appropriate in these aetiologies (particularly in cases of rheumatoid arthritis).
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According to Constant score < 30, there is a clear rupture in the survivorship curve about 7 years after insertion specially in MCTA cases. This suggests that inverted protheses should be used only in cases with severe handicap and only in patients aged over 75.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
