Knee injuries are common in sport, with sprains accounting for half of all athletic-related injuries requiring surgical intervention.1 Although most individuals who suffer a knee sprain will return to full sport participation, knee injuries are often associated with short- and long-term consequences including pain, functional limitations, disability, and decreased health-related quality of life.2–4 A key aspect of the proper management and treatment of acute knee sprains is a comprehensive and efficient evaluation process.5–7 As guided by best practices, the comprehensive evaluation of sport-related injuries includes taking a thorough history and performing a battery of clinical assessments such as orthopedic provocative (also known as special) tests to determine an appropriate diagnosis.5–7
Following the history portion of a patient examination, clinicians typically identify differential diagnoses to guide the clinical examination, which includes the selection of orthopedic provocative tests.5–7 Although this global process is relatively straightforward, the high number of available orthopedic provocative tests can make the test selection process a challenging task, particularly for sports medicine practitioners (eg, athletic trainers or physicians) who often have to make quick decisions on the field or within a busy clinic environment. For example, there are more than 25 available orthopedic provocative tests to consider when evaluating for a possible anterior cruciate ligament injury.8 In practice, the selection of orthopedic provocative tests should be based on the clinician's estimation of the probability of a condition from the clinical examination and patient history.5–7 However, the decision to perform a specific orthopedic provocative test could also come from how an individual was taught to evaluate for a specific condition, which may or may not be based on best evidence.
Within the context of evidence-based practice, the selection of orthopedic provocative tests should be based on both the best available evidence and clinical experience when possible.9,10 Evidence related to orthopedic provocative tests is often associated with the test's diagnostic accuracy in including values related to the sensitivity, specificity, likelihood ratios (negative and positive), and diagnostic odds ratios.10,11 Despite current efforts to encourage evidence-based practice, it is unknown which tests sports medicine practitioners are selecting during the evaluation process of knee sprains at the point-of-care. Understanding the current practice patterns of athletic trainers' use of orthopedic provocative tests for specific knee conditions may help identify gaps in patient care and guide future evidence-based practice educational efforts. Therefore, the purpose of this retrospective study was to describe orthopedic provocative tests commonly used by athletic trainers to diagnose knee sprains.
Design and Setting
This study was a retrospective analysis of de-identified electronic medical records within the Athletic Training Practice-Based Research Network. The Athletic Training Practice-Based Research Network and its features, including the infrastructure, electronic medical records, clinician training, and data collection methods, have been described in previous investigations.12–14 The study was exempted by the local institutional review board because it was an analysis of de-identified records.
Patients who were diagnosed as having a sport-related knee sprain by an athletic trainer within the Athletic Training Practice-Based Research Network between October 2009 and October 2015 were included in this study.
For this study, data were extracted from the patient demographics and injury evaluation forms within the electronic medical records. All data were recorded by an athletic trainer working at one of 63 athletic training clinics (secondary school: n = 53, 84%; college: n = 10, 16%) across 15 states within the Athletic Training Practice-Based Research Network during the study period. Prior to data collection, athletic trainers were required to complete a training program that provided best practices for patient care documentation within the electronic medical records.12–14
Patient cases were identified by using International Statistical Classification of Diseases and Related Health Problems-9 (ICD-9) diagnostic codes for the primary pathology, which included cruciate ligament sprains (anterior and posterior cruciate ligament; ICD-9: 844.2), medial collateral ligament sprains (ICD-9: 844.1), and lateral collateral ligament sprains (ICD-9: 844). The ICD-9 coding system reports anterior and posterior cruciate ligament injuries under the same code. Thus, anterior and posterior cruciate ligament injuries were grouped together for this study. Athletic trainers recorded the diagnosis as the primary pathology based on their clinical examination. Because data were recorded by athletic trainers during the routine course of patient care, confirmatory diagnostic tests such as magnetic resonance imaging were not required as part of data collection.
Electronic medical records, including their features and functionality, have been described in detail in previous studies.12–14 For the current study, data were extracted from the patient demographic and injury evaluation forms within the electronic medical records. The patient demographic form provides basic patient information including sex, sport, age, height, and mass. The injury evaluation form is a region-specific form that captures major components of the clinical examination, including diagnosis, mechanism of injury, weight bearing status, range of motion, strength tests (ie, manual muscle testing), flexibility testing, neurological testing, functional tests, and provocative tests. Provocative tests and their associated test results were recorded using drop-down menus. Drop-down options for provocative tests included anterior drawer, posterior drawer, Lachman, valgus stress, varus stress, Apley compression, Apley distraction, other (free textbox), and no tests performed. Drop-down options for test results were recorded for the involved and uninvolved sides using the following options: positive, negative, inconclusive, and not performed. The electronic medical records allowed the athletic trainers to enter as many provocative tests as necessary. If no provocative tests were performed for the patient, the athletic trainer entered “no tests performed” for this electronic medical records field.
Patient cases were group based on primary diagnosis. For each patient case, we identified the orthopedic provocative test(s) used by the athletic trainer and the result of each test (positive, negative, inconclusive, or not performed) for the involved side of the patient. All variables were reported as percentages and frequencies. The most frequently used orthopedic provocative tests were reported for each injury diagnosis.
A total of 173 athletic trainers practiced at these clinical practice sites during the study period. Most athletic trainers were female (60.7%) and held a master (53.9%), doctoral (32.2%), bachelor (10.4%), or “other” (3.5%) degree. On average, the athletic trainers were 29.4 ± 8.1 years of age, certified for 4.4 ± 6.3 years, and employed at their current site for 1.6 ± 4.5 years. The athletic trainers were primarily employed as an assistant/associate athletic trainer (42.5%), head athletic trainer (25.7%), graduate assistant athletic trainer (20.4%), or “other” (eg, director, faculty, or intern) (11.4%), and worked on a full-time (33.9%), part-time (32.2%), outreach (21.8%), or “other” (12.2%) basis.
A total of 7,229 injuries were evaluated during the study period, with knee injuries accounting for 5.9% (n = 1,215) of all injuries. Of the documented knee injuries, 263 patients (male: 171, age: 17.5 ± 2.4 years, height: 177.5 ± 11.8 cm, mass: 85.0 ± 20.1 kg; female: 92, age: 17.5 ± 2.0 years, height: 162.7 ± 11.4 cm, mass: 60.6 ± 11.1 kg) were diagnosed as having a knee sprain injury during the study period (103 anterior/posterior cruciate ligament, 120 medial collateral ligament, and 40 lateral collateral ligament sprains).
The ICD-9 code for cruciate ligament sprains (ICD-9: 844.2) includes both anterior and posterior cruciate ligaments; therefore, we were unable to separate provocative tests used for anterior versus posterior cruciate ligament sprains. Collectively, for anterior/posterior cruciate ligament injuries, athletic trainers documented using 4.7 ± 2.2 provocative tests, with the Lachman (n = 96, 93.2%), valgus stress (n = 79, 76.7%), anterior drawer (n = 76, 73.8%), varus stress (n = 72, 69.9%), and posterior drawer (n = 55, 53.4%) being the most commonly recorded tests (Table 1). Athletic trainers documented using 4.8 ± 1.9 tests for medial collateral ligament injuries. The valgus stress (n = 117, 97.5%), Lachman (n = 96, 80.0%), varus stress (n = 88, 73.3%), anterior drawer (n = 75, 62.5%), and posterior drawer (n = 60, 50.0%) tests were the most frequently documented tests for injuries diagnosed for the medial collateral ligament (Table 2). Athletic trainers documented using 4.6 ± 1.3 provocative tests for lateral collateral ligament injuries, with the varus stress (n = 34, 85.0%), valgus stress (n = 34, 85.0%), anterior drawer (n = 29, 72.5%), Lachman (n = 27, 67.5%), and posterior drawer (n = 20, 50.0%) tests being the most frequently reported tests (Table 3).
Tests for Anterior and Posterior Cruciate Ligament Injuries (n = 103)
Tests for Medial Collateral Ligament Injuries (n = 120)
Tests for Lateral Collateral Ligament Injuries (n = 40)
To our knowledge, our study is the first to describe the practice patterns of athletic trainers regarding their use of orthopedic provocative tests for the evaluation of knee sprains. The Lachman, anterior drawer, posterior drawer, and valgus and varus stress tests were identified as the most frequently documented orthopedic provocative tests used in diagnosing knee sprains. Although our study only included athletic trainers, we believe that the findings from this study are useful for the general sports medicine community. Indeed, recent evidence suggests that athletic trainers and sports medicine physicians demonstrate similar assessment patterns and report high levels of agreement (92%) regarding diagnoses of sport-related injuries.15
The use of the Lachman, anterior drawer, posterior drawer, and valgus and varus stress tests by athletic trainers is a promising finding because the current evidence suggests that these tests possess the best diagnostic accuracy values currently available.8 Diagnostic accuracy can be assessed using a variety of values, including sensitivity, specificity, likelihood ratios (negative and positive), and odds ratios of the orthopedic provocative test.10,11 From a clinical perspective, sensitivity and specificity values are commonly used because the values are relatively easy to interpret for clinical use and apply to the decision-making process. Sensitivity and specificity values can range from 0 to 100, with higher values indicating better clinical use.10,11 A test with high sensitivity helps to rule out a pathology with a negative test result, whereas a test with high specificity helps to rule in a pathology with a positive result.10,11 Thus, a test with both high sensitivity and high specificity is preferable because either test result (negative or positive) will offer information to guide the decision-making process.
Due to the formatting of the ICD-9 coding system, we were unable to delineate findings specifically based on anterior or posterior cruciate ligament injuries. Our results indicate that the most common orthopedic provocative tests used for assessing a cruciate ligament sprain are the Lachman and anterior drawer tests. These findings are comparable to those reported in a meta-analysis of pooled data by Benjaminse et al.,8 who reported that the Lachman (sensitivity: 85%, specificity: 94%), anterior drawer (sensitivity: 55%, specificity: 92%), and pivot shift (sensitivity: 24%, specificity: 98%) tests were the most common orthopedic provocative tests used for identifying anterior cruciate ligament sprains in patients without anesthesia.8 The Lachman test appears to possess great clinical usefulness due to its high sensitivity and specificity values as compared to the anterior drawer and pivot shift tests.8 Our findings suggest that athletic trainers favor the Lachman test (used for 93% of patients) over the anterior drawer (used for 76% of patients) and pivot shift (used for 1.9% of patients) tests when evaluating cruciate ligament sprains. Interestingly, our study suggests that the pivot shift test was rarely used by the athletic trainers in our study, particularly when comparing our findings to those reported by Benjaminse et al.8 The rare use of the pivot shift test by athletic trainers in our study may be due to potential limitations of the test as reported by Benjaminse et al.,8 which include the low sensitivity of the test, the potential discomfort that the test causes in the patient, and/or the difficulty of interpreting the findings at times. However, our findings generally suggest that the assessment patterns of athletic trainers within the Athletic Training Practice-Based Research Network follow the best available evidence in the current literature.
Although the posterior drawer test is most commonly used for the evaluation of cruciate sprains, there is surprisingly limited evidence related to its diagnostic accuracy, including sensitivity and specificity values. Evidence surrounding the diagnostic accuracy of the posterior drawer test is more than 15 years old and varied.16 The literature suggests that the posterior drawer test has high ranges of sensitivity (6 studies identified a range of 51% to 100%), with few studies reporting on the specificity (1 study; 99%) of the test.16,17 Future studies should be conducted regarding the diagnostic accuracies surrounding the posterior drawer test.
Similar to the posterior drawer test, there is limited available evidence related to the valgus and varus stress tests. In a meta-analysis conducted by Malanga et al.17 investigators reported only three studies9,18,19 that identified the diagnostic accuracy of the valgus stress test, with a large range of values for sensitivity (68% to 96%) and no values reported for specificity.17 For the varus stress test, only one study was identified that reported a sensitivity value of 25% and offered no specificity values.8 Our data suggest that athletic trainers used the valgus and varus stress tests for collateral ligament sprains almost all of the time and for cruciate ligament sprains most of the time. However, there is little evidence to support its use in examining knee sprain injuries.17 Further research needs to be conducted to identify specificity values and current sensitivity values.
At this time, it is recommended that sports medicine practitioners use multiple orthopedic provocative tests when diagnosing knee ligament sprains and do not rely on a single orthopedic provocative test to make a clinical decision.20 Instead, proper diagnosis should be conducted through a battery of tests to help rule in or out a pathology while associating medical history findings such as a popping sensation, giving way, effusion, or immediate pain following trauma.5–7,20 Our findings suggest that athletic trainers use four to five orthopedic provocative tests on average that have the best clinical usefulness available based on existing evidence when evaluating for knee ligament sprains. This study suggests that athletic trainers in the Athletic Training Practice-Based Research Network are following best practices by using a battery of tests to help rule in and/or out conditions to diagnose knee sprain injuries. However, despite our ability to determine the average number of tests used for each diagnosis and identify the tests being used, we were unable to capture the specific order in which the tests were performed.
Understanding which specific tests are performed by sports medicine practitioners may provide insight about the process of clinical decision making during evaluation through the use of likelihood ratios and changes in pretest and posttest probabilities. Pretest probability is the clinician's probability of the patient having a condition prior to performing any hands-on clinical testing.10,11 For example, the pretest probability is often influenced by findings related to the history (eg, mechanism of injury or feeling a pop or not) and visual presentation (eg, swelling or effusion) of the patient. In contrast, posttest probability is the result of the orthopedic provocative tests' sensitivity and specificity values and the pretest probability of a condition after evaluation.10,11 Depending on the likelihood ratio and actual result of an orthopedic test, the probability that a pathology may exist will increase or decrease. For example, the positive and negative likelihood ratios of the Lachman tests are 9.4 and 0.1, respectively.8 Thus, with a pretest probability of 40% based on the mechanism of injury and symptoms following injury,8 a positive test result would increase the probability of the presence of an anterior cruciate ligament sprain to 88%, whereas a negative result would decrease the probability to 7%. Further, if the sports medicine practitioners followed a positive Lachmans test with an anterior drawer test that was also positive, the probability of an anterior cruciate ligament injury being present would increase from 88% to 90%. Thus, understanding the sequencing of tests performed by sports medicine practitioners may provide more insight into the decision-making process and should be explored in future investigations.
To follow best practices in an evidence-based practice manner, sports medicine practitioners should continue to stay abreast of current evidence to maintain or improve their quality of care. Recent evidence suggests that a new orthopedic provocative test called the Lever Sign has good diagnostic accuracy and may be easier to perform than the Lachman test.21 In a recent study by the developers of the Lever Sign, findings suggested that this new orthopedic test has sensitivity and specificity values of 100% for anterior cruciate ligament sprains.21 Although this test seems promising, it should be noted that many studies related to the diagnostic accuracy of orthopedic provocative tests showed higher values in the initial investigation conducted by the test's developers than in subsequent investigations.22 Thus, more research is needed to demonstrate the diagnostic accuracy of the Lever Sign test.
The current study is not without limitations. As a retrospective analysis of medical records, we relied on ICD-9 coding to identify the diagnoses of interest. Unfortunately, ICD-9 codes group cruciate ligaments together, making it difficult to distinguish practice patterns specific to anterior and posterior cruciate ligament sprains. Thus, future studies should attempt to delineate patterns based specifically on these injuries. Also, because data were collected as part of routine care, confirmatory diagnostic tests such as magnetic resonance imaging were not required as part of the documentation process, making misdiagnoses a potential limitation. Finally, due to the free form structure of the electronic medical records, we were unable to determine the specific sequence of tests performed or identify clinical reasoning patterns for test use. Understanding the test order would help us to better understand why clinicians are using the tests they chose from either a pretest probability or a clinician education standpoint. Despite these limitations, we believe that our results are among the first to describe assessment patterns occurring during routine clinical practice and offer insight into the use of orthopedic provocative tests at the point-of-care.
Implications for Clinical Practice
Our findings suggest that athletic trainers use four to five orthopedic provocative tests on average when evaluating for knee ligament sprains that have the best clinical usefulness available based on existing evidence. Further, our results suggest that athletic trainers who are members of the Athletic Training Practice-Based Research Network follow best practices by using a battery of tests to help rule in and/or out conditions to assist in the diagnosis of knee sprain injuries. Regardless of the injury, the most frequently used provocative tests for sport-related knee sprains were the Lachman, valgus and varus stress, and anterior and posterior drawer tests. However, more research is needed to further demonstrate the diagnostic accuracy of commonly used orthopedic provocative tests, including the valgus and varus stress tests. Understanding practice patterns, such as with the selection and use of provocative tests, can help guide educational and research efforts to better support evidence-based practice. Future research should explore the clinical reasoning related to the order of provocative tests performed and whether sports medicine practitioners are effectively using diagnostic accuracy values to guide the clinical decision-making process.
- Rechel JA, Collins CL, Comstock RD. Epidemiology of injuries requiring surgery among high school athletes in the United States, 2005 to 2010. J Trauma. 2011;71:982–989. doi:10.1097/TA.0b013e318230e716 [CrossRef]
- Cameron KL, Thompson BS, Peck KY, Owens BD, Marshall SW, Svoboda SJ. Normative values for the KOOS and WOMAC in a young athletic population: history of knee ligament injury is associated with lower scores. Am J Sports Med. 2013;41:582–589. doi:10.1177/0363546512472330 [CrossRef]
- Lam KC, Thomas SS, Valier ARS, McLeod TCV, Bay RC. Previous knee injury and health-related quality of life in collegiate athletes. J Athl Train. 2017;52;534–540. doi:10.4085/1062-6050-50.5.01 [CrossRef]
- Lohmander LS, Ostenberg A, Englund M, Roos H. High prevalence of knee osteoarthritis, pain, and functional limitations in female soccer players twelve years after anterior cruciate ligament injury. Arthritis Rheum. 2004;50:3145–3152. doi:10.1002/art.20589 [CrossRef]
- Calmbach WL, Hutchens M. Evaluation of patients presenting with knee pain: Part I. History, physical examination, radiographs, and laboratory tests. Am Fam Physician. 2003;68:907–912.
- Calmbach WL, Hutchens M. Evaluation of patients presenting with knee pain: Part II. Differential diagnosis. Am Fam Physician. 2003;68:917–922.
- Schraeder TL, Terek RM, Smith CC. Clinical evaluation of the knee. N Engl J Med. 2010;363:e5. doi:10.1056/NEJMvcm0803821 [CrossRef]
- Benjaminse A, Gokeler A, van der Schans CP. Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis. J Orthop Sports Phys Ther. 2006;36:267–288. doi:10.2519/jospt.2006.2011 [CrossRef]
- Garvin GJ, Munk PL, Vellet AD. Tears of the medial collateral ligament: magnetic resonance imaging findings and associated injuries. Can Assoc Radiol J. 1993;44:199–204.
- Zou G. From diagnostic accuracy to accurate diagnosis: interpreting a test result with confidence. Med Decis Making. 2004;24:313–318. doi:10.1177/0272989X04265483 [CrossRef]
- Mallett S, Halligan S, Thompson M, Collins GS, Altman DG. Interpreting diagnostic accuracy studies for patient care. BMJ. 2012;345:e3999. doi:10.1136/bmj.e3999 [CrossRef]
- Lam KC, Valier AR, Anderson BE, McLeod TC. Athletic training services provided during daily patient encounters: a report from the Athletic Training Practice-Based Research Network. J Athl Train. 2016;51:435–441. doi:10.4085/1062-6050-51.8.03 [CrossRef]
- Lam KC, Snyder Valier AR, Valovich McLeod TC. Injury and treatment characteristics of sport-specific injuries sustained in inter-scholastic athletics: a report from the Athletic Training Practice-Based Research Network. Sports Health. 2015;7:67–74. doi:10.1177/1941738114555842 [CrossRef]
- Valovich McLeod TC, Lam KC, Bay RC, Sauers EL, Snyder Valier ARAthletic Training Practice-Based Research Network. Practice-based research networks, Part II: a descriptive analysis of the Athletic Training Practice-Based Research Network in the secondary school setting. J Athl Train. 2012;47:557–566. doi:10.4085/1062-6050-47.5.05 [CrossRef]
- Lombardi NJ, Tucker B, Freedman KB, et al. Accuracy of athletic trainer and physician diagnoses in sports medicine. Orthopedics. 2016;39:944–949. doi:10.3928/01477447-20160623-10 [CrossRef]
- Rubinstein RA Jr, Shelbourne KD, McCarroll JR, VanMeter CD, Rettig AC. The accuracy of the clinical examination in the setting of posterior cruciate ligament injuries. Am J Sports Med. 1994;22:550–557. doi:10.1177/036354659402200419 [CrossRef]
- Malanga GA, Andrus S, Nadler SF, McLean J. Physical examination of the knee: a review of the original test description and scientific validity of common orthopedic tests. Arch Phys Med Rehabil. 2003;84:592–603. doi:10.1053/apmr.2003.50026 [CrossRef]
- Harilainen A. Evaluation of knee instability in acute ligamentous injuries. Ann Chir Gynaecol. 1987;76:269–273.
- McClure PW, Rothstein JM, Riddle DL. Intertester reliability of clinical judgments of medial knee ligament integrity. Phys Ther. 1989;69:268–275. doi:10.1093/ptj/69.4.268 [CrossRef]
- Swain MS, Henschke N, Kamper SJ, Downie AS, Koes BW, Maher CG. Accuracy of clinical tests in the diagnosis of anterior cruciate ligament injury: a systematic review. Chiropr Man Therap. 2014;22:25. doi:10.1186/s12998-014-0025-8 [CrossRef]
- Lelli A, Di Turi RP, Spenciner DB, Dòmini M. The “Lever Sign”: a new clinical test for the diagnosis of anterior cruciate ligament rupture. Knee Surg Sports Traumatol Arthrosc. 2016;24:2794–2797. doi:10.1007/s00167-014-3490-7 [CrossRef]
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Tests for Anterior and Posterior Cruciate Ligament Injuries (n = 103)
|Valgus stress||15||59||5||79 (76.7)|
|Anterior drawer||39||19||18||76 (73.8)|
|Varus stress||12||58||2||72 (69.9)|
|Posterior drawer||6||45||4||55 (53.4)|
|Patellar apprehension||2||27||1||30 (29.1)|
|No test performed||N/A||N/A||N/A||16 (6.4)|
|Apley compression||2||8||2||12 (11.6)|
|Apley distraction||0||6||1||7 (6.8)|
|Pivot shifta||2||0||0||2 (1.9)|
|Posterior saga||0||1||0||1 (1.9)|
|Patellar grinda||0||1||0||1 (1.0)|
|Godfrey 90–90a||0||1||0||1 (1.0)|
Tests for Medial Collateral Ligament Injuries (n = 120)
|Valgus stress||101||10||6||117 (97.5)|
|Varus stress||2||85||1||88 (73.3)|
|Anterior drawer||0||65||10||75 (62.5)|
|Posterior drawer||58||0||2||60 (50.0)|
|Patellar apprehension||3||26||1||30 (25.0)|
|Apley compression||3||12||0||15 (12.5)|
|No test performed||N/A||N/A||N/A||9 (13.3)|
|Apley distraction||2||6||0||8 (6.6)|
|Patellar grinda||1||3||0||4 (3.3)|
|Bounce homea||0||0||1||1 (0.8)|
Tests for Lateral Collateral Ligament Injuries (n = 40)
|Valgus stress||2||32||0||34 (85.0)|
|Varus stress||31||0||3||34 (85.0)|
|Anterior drawer||0||25||4||29 (72.5)|
|Posterior drawer||0||18||2||20 (50.0)|
|Patellar apprehension||1||4||1||6 (15.0)|
|No test performed||N/A||N/A||N/A||4 (10.0)|
|Apley compression||0||2||0||2 (5.0)|
|Apley distraction||0||1||0||1 (2.5)|
|Patellar grinda||1||0||0||1 (2.5)|