BFR Therapy After ACL Reconstruction

Patients will be randomized to either BFR therapy or no BFR therapy. Randomization will be
carried out using block randomization with blocks of 6.

Those undergoing BFR therapy will have a Delfi Personalized Tourniquet System (PTS) cuff
applied to the proximal thigh of their operative leg and inflated to 80% limb occlusive
pressure (LOP) calculated by the Delfi PTS device during physical therapy (PT) sessions from
day 2 after surgery through day 7 after surgery. Those in the no BFR group will have the
Delfi PTS cuff applied to their proximal thigh with inflation of the tourniquet to minimal
pressure only. BFR therapy will be administered by health care providers who have undergone
training and certification for BFR therapy with the Delfi PTS device.

Both groups will undergo the following PT regimen two times daily beginning on the day after
the surgical procedure and lasting for 6 weeks post-operatively:

- Quad sets = x1 min isometric hold, 30 sec off, 3 sets

- Terminal knee extensions = 3x15, 30 sec rest or short arc quads sitting 1 x 30 + 3 x 15,
30 sec rest

- Once range of motion (ROM) allows: Bike 10 mins, low to no resistance

Each physical therapy visit will last approximately 60 minutes. During that time, there will
be a total estimated time of 5-7 minutes during which the tourniquet cuff will be on the
thigh, and the tourniquet will be inflated for a similar time period. The tourniquet will
inflate for about 1 minute in order to find out the specific pressure for the patient's leg
and then will remain inflated until exercises are completed, which should take 4-6 minutes.
The cuff will then be deflated and is removed from the leg within about 30 seconds of being
deflated.

Patients will have MRI performed pre-operatively and at 6 weeks post-operatively with axial
cuts to 50% femoral length above joint line. Quadriceps cross-sectional area will be measured
by a blinded observer using MRI. Patients will have clinical measurements including thigh
girth, Lachman test, knee joint range of motion, and knee joint swelling performed
pre-operatively, at post-op day 1, post-op day 14, and 6 weeks post-operatively. All clinical
measurements will be performed by a blinded observer. Additionally, patient reported pain
level will be obtained at the same timepoints in which clinical measurements are performed
using visual analog scale.

In order to ensure there are no nerve injuries present in patients prior to undergoing
application and inflation of thigh tourniquet, all patients in the study will have single
shot adductor and/or sciatic nerve blocks to ensure 24 hour period without nerve block prior
to initiation of BFR therapy. Patients included in the study cannot have a nerve block
lasting longer than the day of surgery. To ensure no new nerve deficits are present, the
patients will undergo a physical examination during morning rounding on post-operative day 1
to assess for new nerve deficits.

Inclusion Criteria:

- Age 14-70

- Undergoing ACL reconstruction with patellar tendon autograft

- Full weightbearing after surgery

- Surgery performed within 14 days of ACL injury

- No nerve catheter in place

Exclusion Criteria:

- Meniscal root tears

- radial meniscal tears

- multi-ligament knee injury

- revision ACL reconstruction

- concomitant osteotomies

- concomitant cartilage resurfacing procedures

- fracture preventing full-weightbearing of operated extremity

- previous history of deep vein thrombosis (DVT)

- new nerve injury/findings affecting operative extremity

- active femoral nerve catheter

- nerve block lasting longer than day of surgery

- patients unable to tolerate BFR treatment

- untolerable post-operative pain due to absence of nerve catheter

- proximal thigh girth greater than 34cm

- time to surgery greater than 14 days