Positive Predictive Value of the Lelli’s Test in Diagnosing Anterior Cruciate Ligament Injury taking Arthroscopic Findings as Gold Standard
Background: Arthroscopic examination is the gold standard for diagnosing ACL injury. However, it is an invasive procedure and is only performed in patients with strong clinical suspicion of ACL injury. Among the various clinical methods for the assessment of ACL injury, Lachman, anterior drawer and pivot shift tests are used in routine practice. But all these tests have their own limitations and have very low positive predictive value. Lelli’s test, a recently introduced clinical test has been shown to be superior to these existing tests. It carries a high positive predictive value and can be performed easily in routine clinical setup without any known limitation. However, the available evidence on the positive predictive value of Lelli’s test was limited.
Objective: To determine the positive predictive value of the Lelli's test in diagnosing anterior cruciate ligament injury taking arthroscopic findings as gold standard. Study Design: Cross Sectional Study. Settings: The study was conducted in Department of Orthopedic Surgery, Services Hospital Lahore. Duration: 6 months from approval of this study 11-01-2017 to 10-07-2017. Methodology: This study involved 197 patients of both genders aged between 20-45 years suspected of ACL tear and having a positive Lelli’s test on clinical examination. Arthroscopy was performed in all these patients to determine the presence or absence of ACL tear. The results of arthroscopy were taken as gold standard. Outcome variable was positive predictive value of Lelli’s test which was noted and compared among various age, gender, BMI and duration of symptoms groups. Results: Mean age was 32.82±7.61 years. The mean duration of symptoms was 5.03±2.13 weeks while the mean BMI was 27.35±4.24 Kg/m2.Arthroscopy confirmed ACL injury in 175 (88.8%) patients. Thus, there were 175 true positive and 22 false positive cases which yielded a positive predictive value of 88.8% for Lelli’s test in diagnosing ACL tear taking arthroscopy as gold standard. Conclusion: The positive predictive value of Lelli’s test was found to be 88.8% in diagnosing ACL tear taking arthroscopy as gold standard. It was not affected by patient’s age, gender, BMI and duration of symptoms which make it superior to other clinical tests currently in practice.