Functional Surface Electromyogram of Knee Extensors in Healthy Humans and Patients With Patella-dislocation.

Introduction The kneecap can dislocate due to an accident or also only due to an interior turn in the stretched knee joint out of its sliding bearing. E. Arendt (Arendt 2002) wrote an overview work, in which possible causes and working methods to the patella dislocation are discussed. Despite almost one hundred quotations the authors are not able find the causes and the possible treatment concepts. The study will examined healthy adults (25 female and 25 men) and 25 patients with patella dislocation by a routine applied clinical gait analysis and surface EMG (after the European SENIAM guidelines) in the Laboratory for Gait Analysis Basel of the Children's University Hospital Basel. The combination of gait analysis and the surface EMG with Wavelet analysis may objectify possible reasons for a patella dislocation and compare the intensity pattern of the EMG between the groups.

Method All subjects (healthy and patients with a patella dislocation) will be prior to the study informed about the study and sign the consent from

The investigation will include the following tasks:

• Preparation of the subject for a clinical gait analysis with placing reflecting marker on the lower body according to the maker setup of Davis et al. (Davis III et al., 1991.
• Preparation of the subject for a surface EMG of the muscles: gastrocnemius medialis, tibialis anterior, vastus medialis, vastus lateralis, rectus femoris, biceps femoris, semitendinosus according to the SENIAM-Standard.
• Measurements: 10 trials of level walking in self selected speed and 3 times 5 single leg quads on the force plate.
• System: VICON 460 (6 Cameras, 120 Hz, Oxford Metrics Ltd., UK).
• EMG-System: Zebris, Tuebingen, Germany; Amplifiers: Biovision, Wehrheim, Germany, EMG-Electrodes: Bipolar Ag/AgCl Surface Electrodes Noraxon, Sampling rate: 2520 Hz
• Data analysis: Kinetic-and kinematic data with the Vicon-Software, EMG-Data with Wavelet Package (Biomechanigg, Calgary, Canada)
• Statistical Analysis: ANVOA

Inclusion criteria

• Patient: Patella Dislocation before surgery
• Control: healthy

Exclusion criteria

• Patient: Patella Dislocation not able to walk,
• Patient: using orthosis or crutches
• Control: knee injury (e.g. ACL-rupture)
• Control: leg surgery in the last 5 years
• Control: sport injury in the last 6 month (e.g. Muscle pulling)