Die Biomechanik des instabilen Patellofemoralgelenkes und die stabilisierende Wirkung von Orthesen

Kai Heinrich

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Abstract

It is generally accepted that during knee extension the patella moves medially whereas an instable patella is characterized by a reduced medial movement. This is related to an increased risk of a patella dislocation and the development of a patellofemoral pain syndrome (PFPS). As small variations in the patellar alignment could lead to PFPS, the purpose of a treatment with patellofemoral orthoses is to realign the patella. While there is little evidence to endorse their use, orthoses are frequently used. Therefore, the aim of the present study was to investigate the basic functionality of patellofemoral orthoses and their biomechanical effects on the patellofemoral and tibiofemoral joint.
The first study examined how the basic biomechanics of the patellofemoral joint is affected by the novel Patella Pro orthosis (PP) (Otto-Bock HealthCare GmbH, 2016) and the conventional Genu Train P3 orthosis (BA) (Bauerfeind AG, 2016) with respect to the alignment of the patella in vitro on cadaveric legs. Each leg underwent 10 flexion-extension cycles through a range of 45° to 0°. It was found that the PP orthosis supports a more medial displacement of the patella during knee extension, whereas the BA orthosis had no effect on the patellar alignment.
The second study analysed the effect of the PP orthosis on the patellofemoral kinematics with the aid of a magnetic resonance imaging system. To achieve this, patients with PFPS and instable patella were tested in static knee flexion situations (0°, 10°, 20°, 30°) with different isometric knee joint loads (5 %, 25 %, 50 % of body weight). The results showed a more medial position and a decreased lateral tilt of the patella close to knee extension during low knee load in the PP condition.
The third study investigated the dynamic biomechanical effect of the PP orthosis on the patellofemoral pain and the tibiofemoral kinematics and kinetics. To do this, patients with PFPS and instable patella had to perform vertical counter-movement-jumps (CMJ) and isokinetic knee extensions (IK) (90°/s, 45° to 0°) with maximal effort. Increased knee extension moments were determined by wearing the PP orthosis during CMJ and IK. Furthermore, an increased jump height and a reduced patellofemoral pain were found during CMJ.
The findings of the present study approved the functionality of the PP orthosis. The results indicate that wearing the PP orthosis can contribute to a realignment of the patella, an increased load tolerance of the knee joint and a relief of patellofemoral pain. Consequently, it is reasonable to consider that the PP orthosis is suitable for the treatment of the patellofemoral pain syndrome.
Original languageGerman
Place of PublicationKöln
PublisherDeutsche Sporthochschule Köln
Number of pages160
Publication statusPublished - 2016

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