Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí sinh học quốc tế đề tài : Reverse shoulder arthroplasty leads to significant biomechanical changes in the remaining rotator cuff | Herrmann et al. Journal of Orthopaedic Surgery and Research 2011 6 42 http content 6 1 42 JOURNAL OF ORTHOPAEDIC SURGERY AND RESEARCH RESEARCH ARTICLE Open Access Reverse shoulder arthroplasty leads to significant biomechanical changes in the remaining rotator cuff Sebastian Herrmann1 Christian Konig2 Markus Heller2 Carsten Perka1 and Stefan Greiner1 Abstract Objective After reverse shoulder arthroplasty RSA external and internal rotation will often remain restricted. A postoperative alteration of the biomechanics in the remaining cuff is discussed as a contributing factor to these functional deficits. Methods In this study muscle moment arms as well as origin-to-insertion distance OID were calculated using three-dimensional models of the shoulder derived from CT scans of seven cadaveric specimens. Results Moment arms for humeral rotation are significantly smaller for the cranial segments of SSC and all segments of TMIN in abduction angles of 30 degrees and above p . Abduction moment arms were significantly decreased for all segments p . OID was significantly smaller for all muscles at the 15 degree position p apart from the cranial SSC segment. Conclusions Reduced rotational moment arms in conjunction with the decrease of OID may be a possible explanation for the clinically observed impaired external and internal rotation. Keywords shoulder arthroplasty cuff tear arthropathy reverse shoulder prosthesis biomechanics shoulder moment arms rotator cuff Background Promising early functional results can be achieved with reverse shoulder arthroplasty RSA especially in patients with severe cuff tear arthropathy 1-3 . It also is a salvage procedure for fracture sequelae 4-7 and revision of failed hemiarthroplasty 8 9 even though outcome is less predictable in these patients. Patients suffering from the above conditions experience severe restrictions in their activities of daily living by either loss of function due to the insufficient .
