Aims To assess the extent of osteointegration in two designs of shoulder resurfacing implants. Bony integration to the Copeland cylindrical central stem design and the Epoca RH conical-crown design were compared.
Patients and Methods Implants retrieved from six patients in each group were pair-matched. Mean time to revision surgery of Copeland implants was 37 months (standard deviation (sd) 23; 14 to 72) and Epoca RH 38 months (sd 28; 12 to 84). The mean age of patients investigated was 66 years (sd 4; 59 to 71) and 58 years (sd 17; 31 to 73) in the Copeland and Epoca RH groups respectively. None of these implants were revised for loosening.
Results Increased osteointegration was measured under the cup in the Copeland implant group with limited bone seen in direct contact with the central stem. Bone adjacent to the Epoca RH implants was more uniform.
Conclusion This difference in the distribution of bone-implant contact and bone formation was attributed to the Epoca implant’s conical crown, which is positioned in more dense peripheral bone. The use of a central stem may not be necessary provided there is adequate peripheral fixation within good quality humeral bone.
Take home message: Poor osteointegration of cementless surface replacement shoulder prosthesis may be improved by implant design.
Cite this article: Bone Joint J 2016;98-B:504–11.
S. Ajami: Writing Paper, Data Collection, Data Analysis.
G. W. Blunn: Study Design, Data Interpretation, Writing Paper.
S. Lambert: Performed Surgeries, Data Interpretation, Reviewed Paper Drafts.
S. Alexander: Data Interpretation, Reviewed Paper Drafts.
M. Foxall Smith: Data Collection, Data Analysis.
M. J. Coathup: Study Design, Data Interpretation, Writing Paper.
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
This article was primary edited by G. Scott.
- Received May 29, 2015.
- Accepted November 20, 2015.
- ©2016 The British Editorial Society of Bone & Joint Surgery