[Most frequent causes of autologous graft failure in anterior cruciate ligament replacement]

The aim of this retrospective study was to present a comprehensive overview of the causes of bone-tendon-bone (BTB) autograft failure after primary anterior cruciate ligament (ACL) reconstruction. MATERIAL AnD METHODS: Between 2003 and 2013, we performed revision ACL replacement in 47 patients who had undergone primary BTB autograft ACL reconstruction in other hospitals. The group consisted of 16 women (aged 25 to 48 years) and 31 men (25 to 46 years). Surgery was performed on the right knee in 26 and on the left knee in 21 patients. In each of the 47 patients, two different assessments were made: 1. Analysis of causes of failure based on surgical protocols and/or intra-operative video records taken during most of the procedures. 2. Evaluation of bone tunnel location on lateral knee radiograms, using the method described by Harner for femoral tunnels and that reported by Stäubli and Rauschning for tibial tunnels.

The most frequent cause of knee instability, occurring in 51.1% of the patients, was new trauma to the knee. nontraumatic instability in the remaining 48.9% was due to insuffiiency of the graft, and resulted from an incorrect surgical technique (42.5%) or biological causes (6.4%). The most common surgical mistake found was incorrect bone tunnel placement in the tibia or femur, with a malpositioned femoral tunnel being most frequent. This was diagnosed in 32 patients (68.1% of all patients) and, in 17, was the main or major cause of BTB graft failure.

Based on relevant literature data and our experience, principles for prevention of graft failure after ACL reconstruction can be summarised as follows: 1. harvest of a suffiiently strong BTB autograft 2. accurate anatomical bone tunnel placement 3. appropriate tension of the BTB autograft 4. preventing graft impingement 5. secure graft fiation 6. early functional rehabilitation with an accent on delaying full weight-bearing on the knee (6 to 9 months post-operatively)

New trauma to the knee is the most frequent cause of BTB autograft failure after ACL reconstruction. This can be avoided by participating in a professionally guided rehabilitation programme and not returning to sports activities earlier than 9 months after ACL reconstruction. The most common technical error in ACL reconstruction is non-anatomical tunnel placement in the tibia and femur. Femoral tunnel malposition is most frequent while incorrect tibial tunnel placement, which does not inflence graft failure so much, is less common.