Operative versus nonoperative treatment of anterior cruciate ligament rupture in patients aged 40 years or older: an expected-value decision analysis.

Purpose: Our purpose was to determine the optimal treatment of anterior cruciate ligament (ACL) rupture in patients aged 40 years or older.

Methods: Our method was expected-value decision analysis with sensitivity analysis, which is a systematic tool for quantitating clinical decisions. We evaluated 100 randomly selected individuals aged 40 years or older with regard to the following variables: age, gender, activity level (International Knee Documentation Committee form), and visual analog scale regarding potential outcome preferences. Patients with prior knee injury or surgery were excluded. A decision tree was constructed (operative v nonoperative potential outcomes). Literature review determined probabilities of outcomes. Statistical fold-back analysis calculated optimal treatment. Sensitivity analysis determined the effect of changing the outcome probabilities on the decision.

Results: This study included 69 patients (31 with prior knee injury or surgery were excluded). The mean age was 53 years (range, 40 to 80 years), 48% were men, and the activity level was normally distributed (with a slight lower activity skew as anticipated for an older population). The expected value for operative treatment was 7.99 versus 1.86 for nonoperative treatment. Increasing the probability of surgical complications (sensitivity analysis) decreased the expected value of operative treatment but not below the expected value of nonoperative treatment.

Conclusions: Decision analysis shows that surgery is the optimal treatment of ACL rupture in patients aged 40 years or older. A limitation is that, by convention, decision analysis does not investigate actual patients with the condition.

Clinical Relevance: Individuals aged 40 years or older are extremely averse to accepting potential knee instability during pivoting and thus prefer ACL surgery despite the risk of surgical complications.