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20 year Outcomes and Risks of Re-Injury in Patients with Multiple ACL Ruptures

Objectives: Long term clinical outcomes following modern anterior cruciate ligament (ACL) reconstruction are well established and reported in the literature. Despite this very little is known about the long term outcomes of patients who go on to suffer multiple ACL ruptures and the factors that remain a persistent influence on further re ruptures and contralateral ACL injuries Methods: We identified 36 patients (20 males and 16 females, mean age at time of primary ACL reconstruction 21.6 years) who had a further ACL rupture from a consecutive series of 200 patients who underwent primary ACL reconstruction with hamstring tendon autografts with titanium interference screws between 1993 and 1996. Patients were reviewed prospectively at 1, 2, 7, 15 and 20 years after their original ACL reconstruction. Primary outcome measures were the number of ACL ruptures (including contralateral ruptures) and subsequent revision procedures following primary ACL reconstruction. Posterior tibial slope was assessed on lateral radiographs. Functional and radiological outcomes, assessed using the International Knee Documentation Committee (IKDC) score were compared with an age and sex matched cohort of patients who underwent primary ACL reconstruction. Results: At a median follow up of 19 years (range 14.3 to 20.2 years) 29 patients had undergone revision surgery and 11 patients had sustained 3 or more ACL ruptures (range 3 to 6). The mean age at the time of revision ACL reconstruction was 26.4 years (range 14 to 54 years). The mean posterior tibial slope of those who sustained 3 or more ACL injuries was 12.4, compared to a mean of 9.5 for those who sustained 2 ACL ruptures (p=0.002) and a mean of 8.5 in the control group (p=0.01). There was a significant difference (p=0.003) in the mean IKDC score for those patients who underwent revision surgery (84 points +/- SD 13) compared to an age and sex matched cohort of patients (control group) who had a primary ACL reconstruction (94 points +/- SD 9). Radiological degenerative change was seen in 64% of the revision group compared to 35% of patients within the control group (p=0.015). Conclusion: The causes of a further ACL injury are likely to be multifactorial but increased PTS appears to have a significant association with those patients who suffer recurrent ACL injuries. These patients have poorer functional and radiological outcomes when compared to an age and sex matched cohort of patients undergoing primary reconstruction.