Background:

Failure of graft incorporation and tunnel widening (TW) after anterior cruciate ligament (ACL) reconstruction has been frequently reported in the literature. The etiology of TW is still not fully understood.

Patients and Methods:

This is a prospective randomized study including 60 patients, conducted in a Level I trauma center in Innsbruck, Austria. The study protocol was approved by the hospital ethics committee. This study is planned and conducted following the Consolidated Standards on Reporting Trials (CONSORT) guidelines. Aperture fixation is performed using BioComposite interference screws (Arthrex, Naples, FL). Extracortical fixation is performed using the ACL Tightrope (Arthrex, Naples, FL). TW is measured on CT scan postoperative, after 6 and 24 months. Clinical outcome is determined at 1, 2 after reconstruction, IKDC with KOOS Knee-related QoL subscale, Lysholm, Tegner Activity scores, hop tests and KT-1000 measurements are performed.

Hypothesis:

The purpose of this randomized controlled trail is to determine the influence of two different fixation methods on TW and clinical outcome after anatomic ACL reconstruction using hamstring graft in young and active patients.

The study is a randomized controlled clinical trial and will be conducted at the Traumasurgery Innsbruck. Two different surgical methods are tested: ACL Tightrope reconstruction VS Biocomposite interference screws.

Following eligibility criteria have to be met:

1. Age 18 -40 years
2. ACL insufficiency diagnosed by clinical examination (positive Lachman test and/or pivot shift test) and MRI (complete tear)
3. Not more than 12 month after trauma to the knee
4. Tegner Score 5 to 10

Not eligible if:

1. Earlier major knee injury to the index knee
2. Previous knee surgery (except diagnostic arthroscopy) to index knee
3. Associated knee fractures
4. Associated PCL injury, complete MCL or LCL tear
5. Concomitant severe injury to contra-lateral knee at time of assessment
6. Injury to the lateral/posterolateral ligament complex with increased laxity (positive dial test and external rotation thigh foot angle test),
7. Pregnancy and scope to become within next time
8. A history of deep vein thrombosis (DVT) or a disorder of the coagulative system
9. Claustrophobia
10. General systemic disease affecting physical function, any other condition or treatment interfering with the completion of the trial, including patients with metal devices, pacemaker or motion disorders
11. Chronic systemic use of steroids

Following inclusion and exclusion criteria have to be met:

Inclusion:

1. The ACL injury can be either "isolated" or combined with one or several of the following injuries visualized on MRI and/or arthroscopy:

   • A meniscus tear that is either left untreated or treated with a partial resection
   • A small, stable meniscus tear treated with fixation, but fixation not interfering with the rehabilitation protocol
   • Cartilage changes verified on MRI with arthroscopically determine intact surface

2. A radiographic examination with normal joint status or combined with either one of the following finding:

   • A small avulsed fragment located laterally, usually described as a Second fracture
   • JSN grade 1 or osteophytes grade 1 as determined by the OARSI atlas (Altman et al. 1995)

3. Agreement to participate in the study and signed informed consent prior to inclusion.

Exclusion:

1.Presence of one of the following associated injuries to the index knee as visualized on MRI and/or arthroscopy:

• An unstable longitudinal meniscus tear that requires repair and where the following postoperative treatment (i.e. bracing and limited ROM) interferes with the rehabilitation protocol
• Bi-compartmental extensive meniscus resection
• A cartilage injury representing a full thickness loss down to bone
• A total rupture of MCL/LCL as visualized on MRI

A power analysis was performed, estimating that a minimum of 34 patients (17 in each group) would be required to obtain a power more than 80%.

Inclusion Criteria:

1. The ACL injury can be either "isolated" or combined with one or several of the following injuries visualized on MRI and/or arthroscopy:

   • A meniscus tear that is either left untreated or treated with a partial resection
   • A small, stable meniscus tear treated with fixation, but fixation not interfering with the rehabilitation protocol
   • Cartilage changes verified on MRI with arthroscopically determine intact surface

2. A radiographic examination with normal joint status or combined with either one of the following finding:

   • A small avulsed fragment located laterally, usually described as a Second fracture
   • JSN grade 1 or osteophytes grade 1 as determined by the OARSI atlas (Altman et al. 1995)

3. Agreement to participate in the study and signed informed consent prior to inclusion.

Exclusion Criteria:

1.Presence of one of the following associated injuries to the index knee as visualized on MRI and/or arthroscopy:

• An unstable longitudinal meniscus tear that requires repair and where the following postoperative treatment (i.e. bracing and limited ROM) interferes with the rehabilitation protocol
• Bi-compartmental extensive meniscus resection
• A cartilage injury representing a full thickness loss down to bone
• A total rupture of MCL/LCL as visualized on MRI