Department of Orthopaedics and Tumor Orthopaedics, Münster University Hospital, Albert-Schweitzer-Campus 1, A1, 48149, Münster, Germany.
Int Orthop. 2013 Mar;37(3):451-6. doi: 10.1007/s00264-012-1771-7. Epub 2013 Jan 15.
The functional results after reconstruction of the proximal humerus in tumour surgery are poor. Therefore, a reversed proximal humerus replacement was developed in our institution (MUTARS humerus inverse). A low degree of wear on the polyethylene is required because of the patients' youth and demands on shoulder function. A special type of polyethylene with shock-absorbing properties has been developed to minimise polyethylene wear in the MUTARS inverse proximal humerus replacement. We compared the tribological properties of an anatomical shoulder prosthesis (CAPICA) with the new reversed proximal humerus replacement (MUTARS humerus inverse).
Both prostheses were tested up to 5 × 10(6) cycles. Every millionth cycle the surface was inspected and a gravimetric measurement was performed. A measurement of surface roughness was done before testing and after 5 × 10(6) cycles.
In both prostheses after 5 × 10(6) cycles there were no major defects, such as delamination, observed. In the reversed proximal humerus replacement abrasion of 28 mg/10(6) cycles was detected. The mean abrasion of the anatomical prosthesis was 9.28 mg/ 10(6) cycles.
The glenoid component of the first reversed humerus replacement (MUTARS humerus inverse) has wear properties comparable to those of normal reversed shoulder prostheses. This is important, as this type of prosthesis is used in young patients after resection of bone tumours, with a good functional outcome. It can, therefore, be expected that the revision rate due to wear will be as high as in patients with normal reversed shoulder prostheses.
肱骨近端肿瘤切除术后的功能结果较差。因此，我们医院（MUTARS 反式肱骨置换）开发了一种反向肱骨近端置换术。由于患者年轻且对肩部功能有较高要求，因此需要低程度的聚乙烯磨损。已经开发出一种具有减震性能的特殊类型的聚乙烯，以最大限度地减少 MUTARS 反向肱骨近端置换术中的聚乙烯磨损。我们比较了解剖型肩部假体（CAPICA）和新型反向肱骨近端置换术（MUTARS 肱骨反式）的摩擦学性能。
两种假体均经过 5×10^6 次循环测试。每百万次循环检查一次表面并进行重量测量。在测试前和经过 5×10^6 次循环后进行表面粗糙度测量。
在经过 5×10^6 次循环后，两种假体均未观察到分层等主要缺陷。在反向肱骨近端置换术中，检测到 28mg/10^6 次循环的磨损。解剖型假体的平均磨损为 9.28mg/10^6 次循环。
第一个反向肱骨置换的肩胛盂部件（MUTARS 肱骨反式）具有与正常反向肩部假体相当的磨损性能。这很重要，因为这种类型的假体用于骨肿瘤切除后的年轻患者，功能结果良好。因此，可以预期由于磨损导致的翻修率将与正常反向肩部假体患者一样高。
