Summary
Higher grade of apprehension during the pivot shift test at 1 year after ACL reconstruction significantly influenced poor patient-reported outcomes in three KOOS subscales.
Abstract
Introduction
It is generally believed that, after anterior cruciate ligament (ACL) reconstruction, the pivot-shift examination is a better measure of clinical outcomes than instrumented knee laxity or Lachman examination. The purpose of this study was to identify factors that affect inferior patient-reported outcome (PRO) after ACL reconstruction.
Methods
From a prospective multicenter cohort, 665 patients who underwent ACL reconstruction using hamstring tendons were identified at 1 years after the surgery. Each patients underwent an arthrometer assessment and pivot-shift test and completed PRO assessments with the Knee injury and Osteoarthritis Outcome Score (KOOS) before and one year after the surgery. Pivot shift test was graded according to conventional IKDC grading (grade 0 to 3) as well as subjective apprehension grading (grade 0 to 3). Age, sex, duration between injury and surgery, ACL reconstruction techniques, treatment methods for meniscus, articular cartilage conditions, each pivot shift test grade, anterior knee laxity, and other variables were assessed by multiple linear regression analyses to identify factors that affect inferior PRO after ACL reconstruction.
Results
Older age at ACL reconstruction was a significant factor that affect inferior PRO in all of the five KOOS subscales. Extension disturbance of the knee at 1 year after the surgery significantly affected poor PRO in four KOOS subscales. Higher grade of the apprehension during the pivot shift test at 1 year after the surgery significantly influenced poor PRO in three KOOS subscales (symptoms, knee-related quality of life, and sport and recreation function). Articular cartilage injury at the trochlear groove significantly affected poor PRO in two KOOS subscales (pain and activities of daily living). Lateral meniscal repair, articular cartilage injury at the lateral femoral condyle, flexion disturbance of the knee at 1 year after the surgery, and female sex were significant factors that affect inferior PRO in one of the five KOOS subscales. Conventional IKDC grading of the pivot shift test at 1 year after ACL reconstruction did not affect inferior PRO.
Discussion And Conclusion
Several studies have showed that there is little or no relationship between instrumented knee laxity and functional outcome or subjective assessment after ACL reconstruction. On the other hand, a number of investigators emphasized that pivot shift examination was associated with satisfaction with outcome, activity limitation, overall knee function, and sports participation. However, a recent study concluded that rotational instability in ACL-injured knees represented by the pivot shift phenomenon can be evaluated subjectively using the triaxial accelerometer under anesthesia, whereas its use while the patient was awake cannot be reliable. It is sometimes difficult to evaluate an awake patient by the pivot shift test because of the patient’s fear compared to the condition under anesthesia. This study showed that older age at ACL reconstruction and extension disturbance of the knee after the surgery were serious significant factors that affect inferior PRO. In addition, subjective grade of apprehension during the pivot shift test reflected PRO more than conventional pivot shift test grade after ACL reconstruction.