[Flexion contractures of the PIP joints: pathogenesis, classification and results following arthrolysis]

The most frequent cause of flexion contracture is immobilization, which may occur with or without trauma. Posttraumatic flexion contracture mainly develops from direct injury, intraarticular fluid and the physiological muscle balance. Nontraumatic post-immobilisation stiffness is due to biochemical and biomechanic changes as well as processes, which are determined by the metabolic activities of tissue and the lack of stress. Because of the variable and the changing anatomical substrates, and owing to different prognostic factors, it is necessary to subdivide the group of flexion contractures with regard to their prognostic factors. Thus, we recommend to differentiate between simple periarticular contractures, complex periarticular contractures with tenodesis and/or contractures caused by scars, as well as a corresponding classification of corresponding treatment procedures. The results in the literature will then be categorized accordingly within a metaanalysis. With regard to the reduction of flexion contractures and the range of motion, the group of simple periarticular arthrolysis shows better results than the group of complex periarticular arthrolysis. The mediolateral approach is preferred in the first group.