Introduction Long-term individual prognosis and risk factors for quality of life and disability following ACL reconstruction remain unknown. To determine 10 year predictors of knee function after anterior cruciate ligament reconstruction.

Material and methods Prospectively collected data were extracted on patients who underwent ACL reconstruction between January 2005 and January 2007 from the Swedish National Knee Ligament Register. Patients who had no 10 year follow-up of the Knee injury and Osteoarthritis Outcome Score (KOOS) were excluded. Conditional multivariable regression modelling was used to assess 10 year patient-related and surgery-related risk factors across all KOOS subscales including KOOS4.

Result In total, 874 patients with a median age of 27.5 years (11.2–61.5) at ACL reconstruction were included. No patient-related or surgery-related predictor was significant across all subscales of the KOOS. The presence of a concomitant articular cartilage injury resulted in decreased odds OR=0.639–0.796 (p<0.05) for every two-step increase of ICRS grade in four KOOS subscales. A higher preoperative KOOS pain increased the odds of having a favourable KOOS in the subscales of pain, symptom, sport and KOOS4. In a sub-analysis, a higher preoperative body mass index proved to be a significant risk factor in four out of the six KOOS subscales studied.

Conclusion This 10 year risk factor analysis identified several factor than can effect long-term knee function after ACL reconstruction. Most of the risk factors were surgery-related and unfortunately non-modifiable. Nevertheless, this information can be helpful to physicians counselling patients’ expectations of outcome after ACL reconstruction.