Page 221 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

2.1 Soft-tissue failure
Two types of soft-tissue failures can be distinguished: either related to function (“limited function owing to insu cient musculo-ligamentous attachment”), or related to coverage (aseptic wound dehiscence). Few studies explicitly mentioned soft tissue problems as a cause of failure for reconstructions of the extremities, presumably because most soft-tissue complications ultimately either result in infection, or can be managed with a skin graft or myocutaneous ap.
Adequate soft-tissues are of essential importance for optimal functioning of reconstructions of polyaxial joints; a lack of support results in subluxation or recurrent dislocation103. It is, however, di cult to assess the in uence of the extent of soft tissue resection on functional outcome of intercalary reconstructions or knee replacements. On the other hand, we know that muscular support reduces the loads on the adjacent joint104, and extensive soft tissue resection therefore may result in an increased risk of mechanical failure105. The TLEMsafe project, which is currently ongoing, aims to combine a computerized model of the musculoskeletal system and innovative imaging techniques to predict functional e ects of a speci c resection106. Although this model is not able to account for compensatory function of salvaged muscles and it may be questioned whether such a prediction would actually a ect clinical practice, it would be interesting to use such models to calculate mechanical stresses on implants, to predict mechanical failure and, ultimately, to manufacture implants that are optimized to withstand the relevant mechanical stresses.
Loss of extensor mechanism function is a particular concern after tumor resections around the knee105. Osteoarticular allografts have a theoretical advantage over endoprostheses because they o er the possibility to reconstruct the extensor mechanism and may thus result in a less severe extension lag107, 108. On the other hand, synthetic materials may be used to reconstruct the extensor mechanism when using an endoprosthesis. Early synthetic (Terylene) ligaments were abrasive to local tissues and eventually ruptured109. Modern synthetic materials, such as the MUTARS trevira tube58 and LARS tube110 (LARS, Arc-Sur-Tille, France), however demonstrated satisfactory results in the rst clinical studies58, 110, 111. Future studies will have to show whether there is a di erence in outcomes between biological and modern synthetic materials for reconstructions of the extensor mechanism.
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General discussion
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