Initial Graft Tension and ACL Surgery

Damage to the ACL is a common injury that usually requires surgical reconstruction to restore
function and prevent progression of post-traumatic osteoarthritis. However, the
reconstruction procedure frequently causes degenerative changes to the knee joint over time.
The amount of tension applied to the ACL during reconstruction may indirectly affect the
possible onset of arthritis over time. High tension would result in less joint motion during
the initial healing stages, which may make the onset of arthritis less likely. On the other
hand, high tension would result in increased compressive forces between the joint surfaces,
which could lead to arthritis. The purpose of this study is to evaluate the effect of initial
graft tension set during ACL reconstruction surgery on joint cartilage and the development of
knee arthritis over at least a 12-year period.

Participants will include candidates for ACL reconstruction surgery using patellar tendon
grafts. Participants will be randomly assigned to one of two treatment groups:

- Low tension (Group 1) participants will receive low-tension treatment with initial graft
tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee
is equal to that of the uninjured knee.

- High-tension (Group 2) participants will receive high-tension treatment with initial
graft tension set to reduce A-P displacement by 2 millimeters relative to that of the
uninjured knee.

Participants will enroll in this 12-year study 1 to 6 weeks prior to ACL surgery. There will
be two preoperative study visits: one will include magnetic resonance imaging (MRI) and the
other will include a knee evaluation, dynamic function testing, and questionnaires.
Postoperative visits occurred immediately following surgery and at 6, 12, 36, 60, 84, 120 and
144 months following surgery. Strength testing, functional testing, x-rays, questionnaires,
and a knee exam will occur at most postoperative visits. MRIs will occur at some
postoperative visits. An additional group of participants with no evidence of knee injury
will serve as a control. The control group will attend all study visits except for the
12-month visit. All participants may be followed for up to 10 years.

Inclusion Criteria for Groups 1 and 2:

- ACL injury of only one knee (minor meniscal tears involving less than 1/3 of the
meniscus are allowed)

- Candidate for ACL reconstruction surgery using a bone-patellar tendon-bone graft or a
four-stranded hamstring tendon graft (looped semitendinosus and gracilis muscles)

- Tegner activity score of 5 or greater, indicating participant is at least moderately
active

Exclusion Criteria for Groups 1 and 2:

- ACL tear that has occurred more than 12 months prior to surgery

- Moderate-sized fissures or lesions in knee articular cartilage

- Meniscal tears requiring partial removal of meniscus (tears larger than 1/3 of the
meniscus)

Inclusion Criteria for the Control Group:

- Tegner activity score of 5 or greater, indicating participant is at least moderately
active

Exclusion Criteria for All Participants:

- Previous injury to either knee

- Increased laxity of the medial collateral ligament (MCL), lateral collateral ligament
(LCL), or posterior cruciate ligament (PCL), as compared to the uninjured knee

- Radiographic evidence of degenerative arthritis

- Pregnancy

- Any disease that might place a participant at high risk for articular cartilage damage
(e.g., rheumatoid arthritis, osteoporosis, metabolic diseases)