Clinical and Functional Outcome After Lateral Trochlear Lengthening Osteotomy Lateral Trochlear Lengthening Osteotomy

"Collection of clinical measurements:~* Active and passive range of motion (ROM) of the knee, hip and ankle Joint bilaterally.~* Passive patellar translation in 30° of flexion billaterally in quadrants of translation.~* Patellar apprehension test (Fairbank's Test) and the Moving Patellar Apprehension (MPAT) test for the diagnosis of patellar instability. The Fairbank's Test is performed in 30° of Flexion while the MPAT is performed while flexing the knee from 0° to 90°."

"Collection of data for muscle strength:~* Muscle strength will be measured bilaterally using a dynamometer (Biodex System 4 Pro: Biodex Medical Systems, Shirley, NY, USA). For the knee, maximum isokinetic Flexion and extension torques will be collected between full extension and full flexion at a movement speed of 60°/s (3 x 5 repetitions) Maximum joint torques in each movement direction will be recorded for each joint and normalized to body weight"

"Collection of EMG Data:~* Surface electrodes will be placed bilaterally on the vastus medialis and lateralis rectus femoris, biceps femoris and semitendinosus muscles following the guidelines of the SENIAM project (Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles). Simultaneously with the muscle strength measurements, EMG data will be collected using a 12-channel EMG system (myon AG, Schwarzenberg, Switzerland, sampling rate 2400 Hz)."

"Collection of Clinical Scores:~* patient's pain, range of motion and ability to perform daily living activities will be assessed using the Kujala Anterior Knee Pain Scale, Lysholm Knee Score, visual analog scale score (VAS) and the Tegner Activity Score"

Collection of Imaging Data - Radiological measurements: Xrays and MRIs which were already performed as part of the original diagnostic and follow-up procedures pre- and postoperative will be reviewed and analysed.