Journal of IMAB (Feb 2020)
BIOMECHANICAL PRINCIPLES OF SHOULDER JOINT AS A BASIS OF POST FRACTURE ENDOPROSTHESIS REPLACEMENT
Abstract
This article aims to present our academic knowledge in the shoulder joint biomechanics as a basis for post fracture endoprosthetis replacement. MATERIALS AND METHODS: The post fracture trauma type and the dislocation degree are the two causes for often unsatisfactory results of the treatment because of pain, limited motions and loss of strength. In order to restore the anatomy as much possible and as closely to normal, blood reposition with internal fixation is the method of choice for any unstable fractures. Surgical treatment, however, is difficult and problematic because of the difficult access to the fracture and the large fragmentation of pieces. A proximal shoulder bone fracture, which disturbs blood supply of the humeral head, may require placement of a prosthesis. Hemiarthroplastics is a logical approach in such cases, but the analysis of functional results and complications determines a certain number of risk factors, limiting the indications. A strict analysis of the patient characteristics and the fracture type is an essential precondition for making a decision against treatment by immobilization or by osteosynthesis. The results in hemiarthroplastics depend mainly on sticking to appropriate surgical practices, aimed at a stable anatomic osteosynthesis of the surrounding structures so that the normal shoulder function can be restored. Correcting the implant height and retroversion, reducing and fixing the tubercles and the good management of the post operative progress is crucial. Rapid development and manufacture of various types of shoulder implants lead to a significant improvement of results in fracture treatment. In elderly patients, when local conditions are not suitable for hemiarthroplastics, a reverse prosthesis can be used with adjusted surgical technique. Regardless of the prosthesis type, implanting in proximal shoulder bone fracture is an exigent operation with a certain impact on the functional shoulder development. After the Neer report in 1970 about the shoulder prosthesis replacement results in proximal shoulder bone fracture, several attempts have been made to reproduce its encouraging initial findings. Many of them have shown good results regarding the pain, but a lot less satisfactory functional result. CONCLUSION: Knowing the shoulder joint biomechanics is the basis for adequate preoperative planning, for choosing the technique for post fracture endoprosthesis replacement and prescribing an optimal rehabilitation program.
Keywords
