[Patella dislocation: an algorithm for diagnostic and treatment considering the rotation].

BACKGROUND Patella dislocation and re-dislocation are common diseases. Although patella dislocation is frequent, it always poses a challenge concerning diagnostics and therapy. Mixed forms of pathological disorder in the patellofemoral joint make the analysis of the malalignment and the choice of the correct treatment more difficult. MATERIAL AND METHODS By reviewing the available literature of the last few years and taking into account considerations concerning the malalignment, an overview of the necessary diagnostics can be given. Radiographs and MRI are essential parts of the diagnostics after a traumatic patella dislocation. After re-dislocation, more extensive diagnostics are required to determine all pathological aspects of the malalignment. In this situation, a CT scan for measuring the torsion of the femur and the tibia as well as the TT-TG distance (tibial tubercle - trochlea groove), and the full weight-bearing long leg standing radiograph are part of the fundamental diagnostics. RESULTS The results that are presented in the literature provide some indications for a successful treatment. In consideration of the thorough analysis of the malalignment, the torsional correction of the femur and/or the tibia gains a new importance in the patellofemoral joint. The presented algorithm for diagnostics and treatment should make the decision for the best treatment easier. CONCLUSION The proposed algorithm for diagnostics and treatment is only partially founded on evidence-based results. Moreover, it takes into consideration reflections concerning the biomechanics of the patellofemoral joint and the realignment of this joint.