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.
The exercise program of the intervention group will be performed under lower extremity
blood flow restriction. Cuff pressure will be reduced during the breaks. The execution
speed of the exercises will be 2 seconds of contraction followed by 2 seconds of return.
Hold in all isometric exercises will be 3 seconds.
Initial measurements will be taken upon enrollment of participants and will include MRI,
Lachman test, arthrometer, strength, swelling, Lysholm scale, Tegner scale, pain (Vas),
exercise pain (Vas). By the end of 2nd and 4th week, strength, swelling and pain (Vas)
will be reassessed. The final measurements will be taken at the end of the intervention
period and will include all the measurements taken initially.
The participants will be given a home-base exercise program through an electronic
platform which will provide the possibility of monitoring their compliance. At the same
time, through the platform, the correct execution of the exercises will be ensured as all
the exercises will be presented with videos and specific exercise parameters.
Control Group:
The control group will perform an identical program of splinting, exercises, home
exercises and measurements as the intervention group. The blood flow restriction protocol
will be performed in an identical manner to the intervention group, with only difference
being that variables setting will be set at a control program (sham).