Why do anterior cruciate ligament reconstruction fail : failure rate and causes

الملخص EN

Objectives: The purpose of this study was to determine the failure rate and to analyse failure aetiology among patients who undergone primary ACL (anterior cruciate ligament) reconstruction with a description of our experience; as we have obtained good results in most of our patients.

Methods: In our Sport Surgical Department between April 2012 and November 2018, we operated on 934 patients with single bundle ACL reconstruction.

Surgeries were performed by one team composed of two experienced sport surgeons and two trained- fellows in sport surgery.

A total of 54 patients (23 left knees and 31 right knees) were planned for ACL revision after evaluating them clinically and radiologically.

Although there is debate about the definition of ACL, we defined failure as requiring revision if there was objective clinical failure that met one or more of the following: Lachman grade II or III, pivot shift grade II or III, KT-1000/2000 > 5 mm, and/or overall IKDC score C or D.

Exclusion criteria included history of prior ACL reconstruction failure, presence of concomitant ligament injuries, and complex regional pain syndrome.

Instability examination, CT and MRI were done for all patients that met our criteria for failure, and the data collected for all cases before revision surgery included graft type, tunnel drilling technique, graft fixation systems used, Lysholm score, subjective and objective IKDC scores and questionnaire (including whether a traumatic event was absent or present causing instability).

Result: The failure rate of primary ACL reconstruction was 5.8%.

Non-traumatic cause was responsible for the failure in 59.3% of cases, 25.9% due to technical error with aberrant femur tunnel was found as the most common (72.7%).There was significant correlation between non-anatomical femur tunnel and non-traumatic failed cases (P<0.05).

40.9% of traumatic failed cases were also found to have technical error.

Non-traumatic cause is responsible for early ACL revision with significant P-value (p<0.05) and there was no significant graft failure difference between adjustable loop and interference screw graft fixation system (P>0.05).

An elongated graft was the most common mode of graft failure pattern identified arthroscopically in 59.6% of cases.

Conclusion: The best chance to achieve successful ACL reconstruction surgery is in primary index surgery with success rate more than 85%.

However, awareness about aetiologies of failure that could considerably overlap is crucial.

Non-traumatic causes might be the primary cause for the revision.

Despite improvements in surgical techniques, fixation devices, and ACL anatomy, more effort may be needed to lessen the incidence of failure among studies.