Poster 331: ACL Graft Tear or Contralateral ACL Tear: Which is Worse???

OBJECTIVES: Anterior cruciate ligament (ACL) graft tears and contralateral ACL tears are both relatively common following primary ACL reconstruction (ACLR). While some prior studies have combined these injuries as an outcome variable (“subsequent cruciate injury”), there is little prior work comparing the outcomes of these injuries. We hypothesize that patient reported outcome measures (PROMs) and activity level are lower following revision ACLR than following contralateral ACLR. METHODS: From a prospective cohort study of 2333 patients who underwent primary, unilateral ACLR, 298 patients were identified who underwent revision ACLR or contralateral ACLR within 5 years of primary ACLR. Following exclusion of 11 patients who had both injuries, 256 patients were eligible for study inclusion, including 124 patients who underwent revision ACLR and 132 patients who underwent contralateral ACLR. Patients were contacted for follow-up at 6 years after the primary ACL reconstruction and PROMs were collected including subjective International Knee Documentation Committee (IKDC) score, Knee Osteoarthritis pain (KOOS-Pain) and knee-related quality of life (KOOS- QOL) subscales, and Marx activity level. Patient demographic and initial injury factors, surgical factors, and PROMs were compared between groups. Multiple regression models were used to determine whether side of subsequent surgery (revision versus contralateral ACLR) was a significant predictor of outcome. RESULTS: Two hundred trenty-three of 256 patients (87%) were contacted and completed PROMs at 6 years following primary ACLR. The median time from primary ACLR to second ACL surgery was lower in the revision group (1.3 years) than the contralateral group (2.0 years, p < 0.001). The revision group also demonstrated a lower incidence of partial lateral meniscectomy and was more likely to have received an allograft for the primary ACLR. There were no significant differences in age, sex, smoking status, pre- operative knee laxity, articular cartilage status at primary ACLR, medial meniscus status at primary ACLR, sport, or pre-operative PROMs between the two groups. At follow-up, the revision ACLR group demonstrated lower Marx activity level and PROMs than the contralateral injury group (Table 1). When controlling for the above factors, the revision ACL group demonstrated a 7.8 point lower IKDC (p<0.001), a 3.2 point lower KOOS-pain (p=0.012), a 10.4 point lower KOOS-QOL (p<0.001), and 2.0 point lower Marx score (p=0.002) than the contralateral ACLR group. CONCLUSIONS: Patients who undergo revision ACL R demonstrate with poorer PROMs and lower activity level than those who undergo subsequent revision ACLR.