An observational study in ACL Reconstruction, sponsored by Johannes Kepler University of Linz. Completed at 1 site in Austria. Open to participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-04-20.
Sponsored by Johannes Kepler University of Linz · Observational
Injuries to the anterior cruciate ligament are common and are usually treated with reconstruction and subsequent rehabilitation. Many people succeed in return to sport (RTS), but not to the original level. Muscle strength factors can be assessed using isokinetic strength measurements, while the psychological readiness to return to sport can be assessed using the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) questionnaire. In this study, isokinetic strength testing and psychological testing with the ACL-RSI questionnaire 1 to 4 years after ACL reconstruction will be assessed. The study will be conducted at the Institute of Physical Medicine \& Rehabilitation at the Kepler University Hospital. The Biodex System Pro™, a medical device for measuring and training muscle strength, will be used for the isokinetic measurements. The research question is as follows: Is there a correlation between the results of the ACL RSI questionnaire and the results of isokinetic strength testing on the Biodex System 4 Pro™ in test subjects following ACL reconstruction?
512 studies on the registry are indexed under Anterior Cruciate Ligament Injuries; 164 are open to participants now.
This study's enrollment of 30 is below the median of 92 across 127 observational studies indexed under Anterior Cruciate Ligament Injuries.
Browse Anterior Cruciate Ligament Injuries studies →Johannes Kepler University of Linz is the lead sponsor of 32 studies on the registry; 12 are open to participants now.
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Physically active adults who underwent unilateral ACL reconstruction 1 to 4 years ago
Exclusion Criteria:
1 to 4 years after ACL reconstruction, age: 18 - 50 years, physically active
Peak torque (Nm) - Isokinetic dynamometry (Biodex System 4)
The isokinetic dynamometer measures concentric strength in extension and flexion. Isokinetic strength testing at a ROM (range of motion) of 0-90° knee flexion at 3 different speeds. Test protocol at angular velocities of 60°/sec, 180°/sec and 240°/sec.
Time frame: Day 1 (1 to 4 years after ACL reconstruction)
ACL-RSI questionnaire (Anterior Cruciate Ligament-Return to Sport after Injury)
The ACL-RSI is a measure of psychological readiness to return to sport. It contains 12 questions and examines 3 components related to readiness to return to sport: emotions (5 questions), confidence in one's own performance (5 questions) and risk assessment (2 questions). The questions relate to the psychological effects of returning to sport. The respondents answer each question by giving their assessment in steps of ten on a Likert scale from 0 to 100 points. Low scores indicate a negative psychological assessment and high scores indicate a positive psychological assessment. The cut-off value for distinguishing between returnees and non-returnees is 51.3 points. A German version of the questionnaire is used.
Time frame: Day 1 (1 to 4 years after ACL reconstruction)
Isokinetic dynamometry (Biodex System 4)
The isokinetic dynamometer measures concentric strength in extension and flexion including following parameters: Average peak torque (Nm), time to peak torque (sec), angle of peak torque (deg), torque at 30°, torque at 0.18 seconds, max. repetitions to total work, work/body weight, total work, work first third, work last third, work fatique, avg. power, acceleration time (msec), ROM (range of motion, deg), agonist/antagonist ratio (%), hamstring/quadriceps (H/Q) ratio, LSI (limb symmetry index) Isokinetic strength testing at a ROM of 0-90° knee flexion at 3 different speeds. Test protocol at angular velocities of 60°/sec, 180°/sec and 240°/sec.
Time frame: Day 1 (1 to 4 years after ACL reconstruction)
Sports activity
Sports activity before and after surgery in minutes/week
Time frame: Day 1
Time since ACL surgery
Time in months since ACL surgery
Time frame: Day 1
Height
Height of the participant in cm
Time frame: Day 1
Weight
Weight of the participant in kg
Time frame: Day 1
Body Mass Index
Relation of body weight to the square of body height
Time frame: Day 1 (1 to 4 years after ACL reconstruction)
Age
Age of the participant in years
Time frame: Day 1
Plan to share: No
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This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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Johannes Kepler University of Linz