Initial Graft Tension and ACL Surgery

The anterior cruciate ligament (ACL) is one of four strong ligaments connecting the bones of the knee joint. If overstretched, the ACL can tear. Reconstruction of a torn ACL is now a common surgical procedure. The amount of tension applied to the ACL during reconstruction may indirectly affect the possible onset of arthritis over time. The purpose of this study is to determine the effect of initial graft tension set during ACL reconstruction surgery on the progression of knee arthritis over at least a 15-year period.

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 15-year period.

Participants will include candidates for ACL reconstruction surgery using patellar tendon or hamstring 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 15-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, 144 and 180 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 15 years.

Eligibility Criteria:
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)