Extra articular lateral tenodesis in patients with revision anterior cruciate ligament (ACL) reconstruction and high-grade anterior instability

AIMS AND OBJECTIVES: While patients following primary anterior cruciate ligament (ACL) surgery show satisfying results, the outcome after revision ACL reconstruction (ACLR) seems to be less favourable. Failure rates of 14 to 33% have been reported for revision ACLR. The purpose of this study was to evaluate the outcome of patients after revision ACLR. We hypothesize that peripheral knee instabilities are risk factors for failure of revision ACLR. Furthermore, we hypothesize that peripheral stabilisation will reduce the risk of failure. MATERIALS AND METHODS: Between 2013 and 2016, 150 patients were operated with revision ACLR (revision surgery after primary ACL reconstruction). Out of these patients, 73 patients preoperative had a high-grade anterior instability and were included in the retrospective study. High-grade knee anterior instability was defined as high-grade pivot-shift and/or side- to- side difference of more than 5mm in Rolimeter®-testing. An additional extra articular tenodesis was performed in 59 patients during revision ACLR. Patients were clinically examined with a minimum of 2 years after revision surgery (mean 35±6 months) and identified as “failed revision ACLR” and “stable revision ACLR”. RESULTS: Failure of the revision ACLR occurred in 8.2% (n=6) of the cases. Extra articular lateral tenodesis leads to significant lower failure rates in patients with high-grade anterior instability in comparison to patients without further peripheral stabilization (5% vs. 21%, p=0.045). Also, higher postoperative functional scores were shown in the group of additional extra articular lateral tenodesis (Lysholm 89.5±17 vs. 69.5±12, p=0.041; Tegner 6.6±1.4 vs. 4.5±1.4, p=0.009; Cincinnati Rating Scale 91.2±14 vs. 68.5±17, p=0.006). Failure was associated with male sex (n=6 male failures, p=0.017) and obesity (n=4 obese failures with a BMI >30 kg/m2, p<0.001). CONCLUSION: Additional extra articular tenodesis in patients with revision ACL instability and accompanying high-grade anterior instability significantly reduces the risk of failure of revision ACLR. General risk factors of failure of the revision ACLR are obesity and male sex.