Effects of exercise prehabilitation before anterior cruciate ligament reconstruction on functional outcomes during pre- and postoperative rehabilitation - protocol for a single-blinded randomised controlled trial.

Background: Although a benefit of preoperative training prior to anterior cruciate ligament (ACL) reconstruction is likely, there is no consensus on the optimal content (criteria-based programme), supervision (one-on-one guidance or self-administered training) and general setting of preoperative training after ACL injuries. The purpose of this trial is to investigate the efficacy of an individually adaptive, guided, structured and criteria-based preoperative rehabilitation programme in comparison to a non-guided and self-administered home training programme.

Methods: The planned single-blinded randomised controlled trial study was approved by the ethics committee of the German Sport University on June 14, 2022 (ethics application no. 093/2022) and prospectively registered (DRKS-ID: DRKS00030312; date of registration: 26.09.2022). N = 114 participants between 16 and 60 years of age with a unilateral ACL rupture and scheduled ACL reconstruction with a hamstring or quadriceps tendon autograft will be randomly (block-randomisation, 1:1 allocation) and blinded assigned to one of two groups: intervention group (structured, criteria-based, guided prehabilitation training) and comparator group (non-guided, self-administered home training). After surgical reconstruction, patients of both groups participate in the same standard, functional measurement-guided, postoperative rehabilitation programme. Stepwise increasing the functional requirements of the assessments, all participants participate in testing at the day of anamnesis (t1), 1-7 days before surgical reconstruction (t2), day of surgical reconstruction (t3) and 30 (t4), 60 (t5), 90 (t6) and 180 (t7) days post-reconstruction. The primary outcome is the overall self-reported knee condition, assessed by the sum score of all sub-scales of the Knee injury and Osteoarthritis Outcome Score (KOOS). Secondary outcomes include functional outcomes (range of motion, knee flexors and extensors and plantar flexors strength/torque, functional postural control, jumping ability), workability and return to sport (RTS) (psychological readiness, RTS success).

Discussion: The planned study targets to fill a gap in the evidence regarding effective designs of prehabilitation training before surgical ACL reconstruction. Potential difficulties that could affect the conduct of the study are lack of treatment adherence of the patients and high dropout.

Trial Registration: German Register of Clinical Trials DRKS-ID: DRKS00030312 . Registered on 26 September 2022.