Diagnostic Accuracy of Lachman Test in the Evaluation of Anterior Cruciate Ligament Injuries

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1 Nigerian Journal of Orthopaedics and Trauma Copyright 2012 Nigeria Orthopaedic Association Vol 11 (2) December 2012 ORIGINAL ARTICLE Diagnostic Accuracy of Lachman Test in the Evaluation of Anterior Cruciate Ligament Injuries DR. C.A. NKANTA and DR. J.V.S. VIDYA SAGAR* Consultant Orthopaedic & Trauma Surgeon, National Orthopaedic Hospital, Dala, P.M.B. 3087, Kano * Orthopaedic Department & Institute of Arthroscopy and Sports Medicine, Aware Global Hospital, Hyderabad, India. ABSTRACT Background: In most cities and towns in the developing countries there are none or very few centers with sophisticated diagnostic investigative tests. We therefore depend a lot on clinical tests for diagnosis. The Lachman test is a very important test of the integrity of the anterior cruciate ligament. In this prospective study, the accuracy of Lachman test was compared at diagnostic arthroscopy to determine its accuracy in patients with knee injuries. Lachman test was performed in the Out-Patient clinic to determine its accuracy in the diagnosis of anterior cruciate ligament (ACL) rupture in patients with knee injuries Objective: To determine the accuracy of Lachman test in diagnosing patients with knee injuries. Methods: Lachman test was done and was repeated at the Operating Theatre before Arthroscopic examination of the knees to correlate the findings and accuracy of the test. Results: At the Out-Patient Clinic, we examined 56 knees in 56 patients, 55 males and a female with mean age of 32.1 years (range 12-55years). The right knees were 33(58.9%) and the left were 23(41.1%). The knee injuries were due to trauma in 46(86.1%), sports injuries in 9(16.1%) and dancing in 1(1.8%). Out-Patient Clinic Lachman test was truly positive in 47(83.9%), truly negative in 7(12.5%) and with a false negative in 2(3.6%). The sensitivity of Lachman test was 95.9% while the specificity was 100%. Conclusion: Lachman test has a very high sensitivity and specificity in the diagnosis of ACL rupture in knee injuries in the Out-Patient Clinics. Key words: Lachman test, anterior cruciate ligament, knee injuries, Out-Patient Clinics, knee arthroscopy. Introduction Knee injuries constitute a major injury to the musculoskeletal system being a weight bearing joint. In the developing countries it occurs mostly due to trauma following road traffic accident but in the industrialized countries they are seen in sporting arena. 1-8 In Literature there are different clinical tests and Correspondence: Dr. C.A. Nkanta, FWACS: FICS, Consultant Orthopaedic & Trauma Surgeon, National Orthopaedic Hospital, Dala, P.M.B. 3087, Kano cnkanta@yahoo.com; * Orthopaedic Department & Institute of Arthroscopy and Sports Medicine, Aware Global Hospital, Hyderabad, India. opinions vary on the accuracy of some of the clinical diagnostic tests for the rupture of anterior cruciate ligament. Some sophisticated centers in the industrialized countries and some practitioners have gone beyond physical clinical assessment to instrumentation assessment in determining the status of the anterior cruciate ligaments. In developing countries, these exotic investigations like CT scan and MRI are not readily available and affordable while diagnostic arthroscopy is. Damage to the anterior cruciate ligament (ACL) is a major injury to the knee joint, with increasing 1,2 prevalence during sporting activities. To evaluate possible rupture of the anterior

2 Diagnostic Accuracy of Lachman Test in the Evaluation of Anterior Cruciate Ligament Injuries 76 cruciate ligament (ACL), physicians rely on the history and physical examination and primarily 3 diagnostic assessments: the anterior drawer test, the Lachman 1-8 test, and the pivot shift test. Torg & co-workers presented a relatively simple, reliable, inexpensive, and noninvasive clinical test to 2 determine the status of the anterior cruciate ligament. Preliminary findings from these tests, coupled with patient preference and physical demands, help select those who may need further work-up with arthroscopy 9 or magnetic resonance imaging (MRI). The high incidence of false negative drawer's test 1-2,5,10-12 was alluded to by some researchers. Some tested the accuracy of electronic arthrometer 13,14 KT-1000 with inconclusive results. Bach & co-workers in their study showed examiner's variant in the result of the pivot shift test depending on the position of the hip and tibial rotation 15 at the time of assessment. Materials And Methods In order to evaluate the reliability of the Lachman test for diagnosing Anterior cruciate ligament (ACL) ruptures in the Out-Patient Clinic setting, we prospectively followed the clinical and arthroscopic findings of 56 knees in patients that presented to the AWARE GLOBAL HOSPITAL, HYDERABAD, INDIA and other affiliate centers in the three months period of my Arthroscopy fellowship program. Included in this study were all patients who presented with complains of knees injuries from any cause. The Lachman test was performed at the Out- Patient Clinic and another clinical examination repeated at the operating theatre before the arthroscopic surgery for the treatment of the knee derangement, most of which were reconstruction of the anterior cruciate ligaments. Figure 1 :( a) When viewed from the lateral aspect, the silhouette of the inferior pole of patella, infrapatellar tendon, and proximal tibia is one of a slight concavity. (b) With disruption of the anterior cruciate ligament, anterior translation of the tibia obliterates the infrapatellar tendon slope. (2)

3 CA Nkanta and JVS Vidya Sagar Figure 2: Schematic presentation of Lachman test. Figure 3: With the knee extended, the relationship of the femur, medial meniscus, and tibia is significantly changed. The comparatively flat weight-bearing surface of the femur does not obstruct forward motion of the meniscus and tibia when anterior stress is applied. Thus, in instances where there is an isolated tear of the anterior cruciate ligament, anterior stress of the tibia with the knee extended will demonstrate clinically cruciate instability.

4 Diagnostic Accuracy of Lachman Test in the Evaluation of Anterior Cruciate Ligament Injuries 78 Results There were 56 patients with 56 knees that were evaluated. There were 55 males and one female. The age ranged between 12 and 55 years (mean age, 32.1+/-1.2 years). There were 33 (58.9%) right knees while the left sides were 23 (41.1%). Table 1: Causes of Injury Causes of Injury Trauma Sports Injuries Dancing (Recreation) % 46 (86.1%) 9(16.1%) 1(1.8%) The sensitivity of the Lachman test represents the number of patients with anterior cruciate ligament rupture who had a positive test result as was confirmed with examination under anaesthesia at the Operating Theatre and Arthroscopic surgery. This measure of true positive results indicates the degree to which a positive clinical test truly represents the presence of the condition. This is expressed as a percentage, and was 95.9%. The Specificity of Lachman test represents the number of patients with intact anterior cruciate ligament as was confirmed at the Operating Theatre with examination under anaesthesia and Arthroscopic surgery. This measure of true-negative Lachman test results indicates the degree to which a negative clinical test truly represents the absence of the condition. Expressed as a percentage, this was 100%. The major cause of injury was trauma 46 (82.1%) most of which were falls from motorcycle. Sports injury second 9 (16.1%), and only one (1.8%) patient, unexpectedly a male sustained injury while dancing. Table 2: Result of Lachman's test at the Out-Patient Clinic, Operating Theatre Assessment and at Arthroscopic surgery Variable Lachman Positive + Arthroscopy Positive Lachman Negative + Arthroscopy Negative Lachman Negative + Arthroscopy Positive OPD 47 (83.9%) 7 (12.5%) 2 (3.6%) Of the 56 knees examined, Lachman test performed at the Out-Patient Clinic was positive in 47 (83.9%) of the patients and negative in 9 (16.1%) patients. All those patients that had positive Lachman test at the Out-Patient Clinic were confirmed at the Operating Theatre when Lachman test was repeated under anaesthesia and at surgery with arthroscopy examination to have anterior cruciate ligament rupture. Of those 9 (16.1%)patients with negative Lachman test, only 7 (12.5%) were confirmed both at the Operating Theatre and arthroscopic surgery to have intact anterior cruciate ligament, the other 2(3.6%) patients had false negative Lachman test as they were found to have positive Lachman under anaesthesia and further confirmed on arthroscopic surgery. Discussion The principal finding of this study is that Lachman test in assessing patients with knee injuries in the Out- Patient Clinics is a simple, reliable, inexpensive, and noninvasive clinical test to determine the OT 49 (87.5%) 7 (12.5%) 0 status of the anterior cruciate ligament. With a sensitivity of 95.9% and specificity of 100% Lachman test represent the test that can be done in the Out-Patient Clinics for accurate diagnosis of anterior cruciate ligament injuries Lachman test is very simple to perform and can be performed in the knees with acute and chronic injuries without causing much discomfort to the patients. It can be performed by primary care physician and other first line contact doctors with good results. Being able to obtain good and reproducible results, the Lachman test should be performed with the knee in 15 degree of slight flexion. In some patients with big thigh girth I found it difficult to perform this test alone without assistance and this problem can also affect doctors with small hands as one is expected to stabilize the femur with one hand while the other hand moves the tibia. To overcome this problem an assistant can be asked to stabilize the thigh as the thigh is brought out to the side of the examination couch while the examiner flexes the knee to the appropriate degree as he slides the tibia anteriorly. The findings of sensitivity of 95.9% fell within 1,5,7,8,13 those of other researchers who reported

5 CA Nkanta and JVS Vidya Sagar 79 sensitivity ranging from 78% to 99%. Sharma and co- 7 workers reported a sensitivity of 78% in patients examined at the Out-Patient Clinics but their results improved with an increased to 92.9% when the patients were examined under anaesthesia. This result could be explained by the sample size which is twice that analyzed by Sharma and co-workers. Kartz & coworker reported a sensitivity of 77.7% in patients whose injury was within two weeks and 84.6% in those who presented after two weeks of injury. Combining 12 the two groups they observed a sensitivity of 81.8%. This means that care should be taken when examining patients with acute injuries to be able to obtain good results. The specificity in this study correlated well with 7 that of Sharma and co-workers who also reported specificity of 100% even with examination at the Out- 2 patient Clinics. Torg and co-workers reported that Lachman test is the only test specific for anterior 1,5,12,13 cruciate rupture. In a meta-analysis lower specificity between 91% and 96.8% were observed which may be their study methods. Kartz & co-worker reported Out-Patient Clinic assessment specificity for both acute and chronic injuries to be 95% in each group and when a pooled analysis of both groups was done 12 the figure increased to 96.8%. The results of this study highlights the importance of exhaustive relevant history and meticulous clinical examination of patients with knee injuries in the Out- Patient Clinics which should include Lachman test as this test is highly sensitive and specific for the evaluation of patients with anterior cruciate injuries. In developing countries where some cities do not have the luxury of highly sophisticated investigative modalities like Computerized Tomography Scan (CT Scan) or Magnetic Resonance Imaging (MRI), Lachman test has been reported(9)(17) to be the best modality in making a diagnosis of anterior cruciate ligament rupture. Lachman can help to sort out those that may need further specialist treatment. It would have been worthwhile comparing the results in this study with MRI and arthroscopy findings to find out whether there is really benefit of this type of investigative modality considering its high cost. Conclusion This study shows that Lachman test even when performed at the Out-patient Clinics has a very high sensitivity and specificity for the diagnosis of anterior cruciate ruptures in knee injuries. Lachman test is a relatively simple, reliable, inexpensive, and noninvasive clinical test to determine the status of the anterior cruciate ligament in the Out- Patient Clinics. Physicians are encourage to effectively use it before referring their patients for a more sophisticated expensive investigative modalities which the patients may not be able to afford. Acknowledgment I am really grateful to the management and staff of the Institute of Arthroscopy and Sports Medicine, especially Dr. J. V. S. Vidyasagar, Professor and Head of Orthopaedics and the Institute, Aware Global Hospital, Hyderabad, India, for their co-operation and training during this research. References 1. Benjaminse A, Gokeler A, Van der Schans CP.Clinical Diagnosis of an Anterior Cruciate. J Orthop Sports Phys Ther, May 2006.Volume 36 Number 5, pp Torg JS, Conrad W, Kalen V.Clinical Diagnosis of Anterior Cruciate Ligament Instability in the Athlete. Am. J. Sports Med., 1976; Vol.4; No.2, pp Slocum DB, Larson RL.Rotatary Instability of the Knee. Its pathogenesis and a clinical test to demonstrate its presence. J Bone Joint Surg A, 1968; Vol. 50; No. 2, pp Galway HR, MacIntosh DL. The Lateral Pivot Shift: a symptom and sign of anterior cruciate ligament insufficiency. Clin Orthop, 1980; Vol. 147, pp Opstelten W, Scholten RJPM. Physical diagnostic tests for assessing ruptures of the anterior cruciate ligament. : Aust. J. Physiother, 2007, Vol. 53, p McConaghyJR.What is the diagnostic accuracy of the clinical examination for meniscus or ligamentous knee injuries? J Fam Pract 2002; Vol 51; No. 1, 7. Sharma G, Jain DK, Amaravati R.Evaluation of the Clinical Signs of Ligament and Meniscal Injuries. IJO, October- December 2009; Vol.43; Issue 4, pp Werman HA, Paarshe RE, Jake Ott M.III. Knee Trauma: Assessment, Diagnostic, and Management. Trauma Reports, 2004; Vol.5; No.6, pp Boeve BF, Davidson RA, Staab EV. Magnetic Resonance Imaging in the Evaluation of knee Injuries. South Med J,1991; Vol 84, pp Ostrowki, J A. Accuracy of 3 Diagnostic Tests for Anterior Cruciate Ligament Tears. J Athl Train. 2006; 41(1): Kartz JW, Fingeroth RJ.The diagnostic accuracy of rupture of the anterior cruciate ligament comparing the Lachman

6 Diagnostic Accuracy of Lachman Test in the Evaluation of Anterior Cruciate Ligament Injuries 80 test, the Anterior Drawer sign and the Pivot Shift test in acute and chronic knee injuries. Am. J. Sports Med., 1986; Vol.14, No1, pp Scholten RJPM, Opstelten W, van der Plas CG, Bijl D, Devillè WLJM, Bouter LM. Accuracy of physical diagnostic tests for assessing ruptures of the anterior cruciate ligament: A meta-analysis. J Fam Pract, September 2003 Vol. 52, No. 9, pp Abdalla RJ, Camanho GL, Cohen M, Dias L, Jeremias SL Jr., Forqas A. A study on the diagnostic accuracy of the arthrometer KT1000TM in anterior cruciate ligament injuries. Acta Ortop Bras.2005; Vol13, No.4, 14. Arneja S, Leith J.Validity of the KT-1000 knee ligament arthrometer. Journal of Orthopaedic Surgery,2009; Vol.17, No.1, pp Bach BR Jr., warren RF, Wickiewicz TL.The Pivot Shift phenomenon: Results and description of a modified clinical test for anterior cruciate ligament insufficiency. Am. J. Sports Med., 1988; Vol.16, No.6, pp Liu SH, Henry M, Bocchi L. The diagnosis of acute complete tears of the anterior cruciate ligament. J Bone Joint Surg, 1995; Vol.77B, pp