The goal of this retrospective randomized study is to compare two surgical techniques (single vs. double bundle) of ACL (anterior cruciate ligament) reconstructions in participants with rupture of anterior cruciate ligament without major other injuries of the injured knee (exclusion criteria defined).

The main question it aims to answer are:

• which surgery gives better outcome in patients (short- and long-term results)?
• are there any sings of osteoarthritis in an injured knee compared to a healthy knee?

Participants will be invited to our clinic after 15 years to do clinical and functional exams with x-Ray and magnetic resonance imaging (MRI) of both knees. Subjective exams with different scores (Tegner score, Lysholm score..) were also done. The same exam protocol for participant was used again after two years and fifteen years since surgery.

Double bundle (DB) ACL reconstruction has gained popularity in the last few years. Biomechanical and intra - operative studies have shown better antero - posterior and rotational stability after DB vs. single bundle (SB) reconstruction. However, only few studies are found in the literature that have evaluated and compared clinical results between SB and DB ACL reconstruction. All reported studies used hamstrings in both DB and SB techniques. No studies were found that used patellar tendon autograft for the SB.

The purpose of the present study was therefore to evaluate and compare the clinical results of DB hamstring and SB patellar tendon ACL reconstruction techniques.

A total of 40 patients (29 male and 11 female, average (SD) age 36) were randomized during routine surgery (2 years after the surgery) into either double bundle (DB) or single bundle (SB) group. Patients with combined (medial, lateral or posterior) ligamentous injuries were not included in the study. ACL reconstruction in DB group was done by four tunnel hamstring technique with EndoButton femoral and cancellous screw tibial fixation. In the SB group patellar tendon autograft was fixed with titanium interference screws. The same postoperative rehabilitation protocols were used for both groups.

Subjective evaluation comprised IKDC (International Knee Documentation Committee) subjective score, Tegner activity and Lysholm scores. Objective evaluation was done by the IKDC 2000 knee examination protocol. Antero - posterior stability was measured by KT 2000 (knee arthrometer) and by Rollimeter. One leg hop test was performed to assess the functional results. Isokinetic thigh muscle strength measurements on Biodex isokinetic dynamometer were performed.

The same protocol was performed for the clinical exams after 15 years since surgery. A total of 30 patients were examen. Investigators also did imaging of both knees (X-ray and MRI) for checking the sings of osteoarthritis.

Inclusion Criteria:

• complete ACL rupture
• symptoms and clinical sings for rupture of ACL (instability of knee, swelling, pain, reduced knee function,...)
• patient consent
• magnetic resonance with this of kind injury

Exclusion Criteria:

• associated injuries to other knee ligaments
• major meniscus injuries
• X-ray abnormalities of injured knee
• preliminary ACL reconstruction
• associated injury to the other knee

Fo now we are not planning to share any participant data to other researchers.