Page 55 - Demo

ACL reconstruction is not the only factor controlling tibial rotation533Conservative therapy prior to testing was initiated upon diagnosis and consisted of physiotherapy sessions at least 2 times per week. Prerehabilitation was performed according to the Dutch guideline on ACL injury and focused on decrease of effusion, increase of range of motion and quadriceps and hamstrings strengthening exercises. Surgical procedureAll subjects underwent anatomic, single-bundle ACLR using a semitendinosus/gracilis graft as part of usual care. Both tendons were doubled to create a four-strand graft. The femoral tunnel was created independent of the tibial tunnel via an anteromedial portal technique. For femoral fixation a suspension type fixation was used (Endobutton, Smith&Nephew, London, UK). After pretensioning (60N), tibial fixation was performed by using a PEEK screw and plug (Biosure PK, Smith&Nephew, London, UK). Surgical procedures were performed by two orthopaedic surgeons experienced in ACLR. Surgeon allocation was dependent on site of inclusion.Motion data collectionThe motion data collection was performed at the motion lab of UMCG’s Department of Rehabilitation Medicine. The motion lab consists of a 9m walkway with two 40x60 cm force plates (AMTI; Watertown, MA, USA) embedded in the floor. An 8-camera optoelectronic motion capture system (VICON MX, Vicon Motion Systems Ltd., Oxford, UK) sampling at 100Hz was used. The position of 22 14mm spherical markers distributed on the lower extremities according to Hayes and Davis was recorded.11Marker placement was performed by the same researcher during this study. After static and dynamic calibration, joint centres were calculated using VICON Nexus software v2.8 (VICON MX, Vicon Motion Systems Ltd., Oxford, UK). For the complete procedure and its sensitivity, see Keizer and Otten (2020).21All subjects performed three tasks: (1) level walking at a self-selected pace; (2) a single-leg hop for distance (SLHD, maximum forward jump, jumping and landing on the same leg) (see Fig. 1); and (3) side jump (maximum sideways jump, jumping from and landing on the same leg) (see Fig. 2). Mark Zee.indd 53 03-01-2024 08:56