Aim: To report five-year clinical outcomes, including ACL graft survival, contralateral ACL injury, and patient-reported outcomes, following primary ACL reconstruction with supercritical carbon dioxide (scCO2)-sterilised allograft.
Methods: A prospective case series of 144 patients undergoing primary ACL reconstruction with scCO2-sterilised soft tissue allograft was conducted at a single centre between May 2019 and December 2020. Patients with concurrent significant meniscal or chondral pathology were excluded. The primary outcome was ACL graft survival at five years, defined as clinical or radiological evidence of graft failure. Secondary outcomes included contralateral ACL injury, patient-reported outcome measures (IKDC Subjective Score, ACL-RSI), return to sport, and patient satisfaction. Kaplan-Meier survival analysis and univariate Cox regression were performed to assess predictors of graft failure and contralateral ACL injury.
Results: Follow-up of was achieved in 132 (92%) participants at 2, and 121 (84%) at 5 years. ACL graft survival was 91% and contralateral ACL survival was 93% at 5 years. Patients aged 25 years or younger had a fourfold increase in the odds of graft rupture compared with older patients, with a graft survival of 84% in the younger group versus 97% in those over 25 years. Tibial slope, donor tendon type, and donor age were not significantly associated with graft failure or contralateral injury. Among patients with an intact graft at five years (n=107), the median IKDC subjective score was 95 (IQR 10), with 89% achieving PASS thresholds for this measure. The median ACL-RSI score was 77 (IQR 37), with 74% percent of patients returned to their preinjury level of activity. Overall 94% were satisfied or very satisfied with their outcome.
Conclusion: ACL reconstruction with scCO2-sterilised allograft demonstrates five-year graft survival and patient-reported outcomes comparable to those seen in similar soft tissue autograft cohorts. Younger patient age is a significant risk factor for graft failure, consistent with published literature. These findings support the use of scCO2-sterilised allograft as an alternative for primary ACL reconstruction.
