Comparison of Conservative Treatment With Blood Flow Restriction With Standard Management in Total ACL Rupture. "Randomized Clinical Trial"

Methodological design:

For the purposes of the present study, a double-blind, two-arm randomised clinical trial will be conducted. Participants in the intervention group will undergo and exercise protocol with the use of blood flow restriction (BFR). Participants in control group will follow the same exercise protocol but with sham BFR instead. Both groups will follow the same brace protocol.

Intervention group:

The intervention group will consist of people with a recent ACL tear who meet the eligibility criteria. Participants in this group will follow a splint use protocol. In particular, during the first 3 weeks (phase 1) a splint will be used with the knee immobilised at 90°, non-weight bearing walking with the use of walking aids according to age and mobility. During the 4th and 5th week (phase 2) the range of motion of the splint will be set to 60° to 90° and from 30° to 90° respectively. Walking will remain non-weight bearing. During the 6th week (phase 3) the degree of freedom of the splint will be placed at 0° allowing full flexion but preventing hyperextension of the joint. During this phase, partial bearing is allowed with the use of a walking aid. From the 7th week (phase 4) onwards the splint is removed and walking is done with no loading restrictions.

Regarding the exercise program, participants in this group, during phase 1, will perform isometric quadriceps and hamstring contractions guided by a visual stimulus from an electronic hand dynamometer. The exercise parameters will be 75 repetitions divided into 4 sets (30,15,15,15) at 30% of the 1st maximum of the opposite leg. During phase 2, the exercise protocol is maintained as phase 1 with the only differences that the exercises will be performed at 60 degrees too. Additionally, the "sliding" exercise will be added where the heel is dragged on the bed causing knee flexion as well as the skateboard sliding exercise from a seated position in the allowed range of motion. Exercise parameters remain the same for all exercises as previous phase. In the 3rd phase, single leg squats up to 45° are added. Exercise parameters remain the same. In the 4th phase, the exercise protocol changes. Subjects start at a stationary bike for 5 minutes (without BFR) and the quadriceps and hamstrings isometrics are replaced with resistance exercises for extension and knee flexion. Sliding and single-leg squats are performed at an increased range of flexion (up to 90°) and climbing a 30cm step is added. All exercise parameters remain the same as in the previous phases. During the last phase (5th) gait retraining on a treadmill for 5 minutes and Y balance exercise is added. Both of these exercises will be performed without BFR. The break between sets will be 30 seconds and between exercises 1 minute.