of knee motion limits, subluxations, and ligament injury
The
diagnosis
FRANK R.
NOYES,*† MD, JOHN
F. CUMMINGS,‡ MS, EDWARD S. GROOD,‡ PhD, KIMBERLY A. WALZ-HASSELFELD,* AND RANDALL R. WROBLE,* MD
From the *Cincinnati Sportsmedicine and Orthopaedic Center, The Deaconess Hospital, Cincinnati, Ohio, and the ‡Noyes-Giannestras Biomechanics Laboratories, Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, Ohio
tion, and medial-lateral joint space opening within the
ABSTRACT
limits defined in the study. Nine of the 11 correctly diagnosed the instability in the ligaments; there were numerous errors in diagnosis of injury to other ligament structures. The most frequent misdiagnosis (7 of 11 examiners) was the interpretation of the increased external tibial rotation in the ligament-sectioned knee as representing an injury to the posterolateral ligament structures where, in fact, the injury was to the ACL and medial ligament struc-
acceptable
The clinical diagnosis of knee ligament injuries requires the clinician to: 1) estimate the abnormal motion limits that occur in one or more of the six degrees of freedom that comprise three-dimensional motion; 2) determine the abnormal position (subluxation) of the medial and lateral tibiofemoral compartments; and 3) precisely define the anatomical structures injured and degree of that injury. To determine the clinician’s ability to perform these tasks, we evaluated 11 knee surgeons’ clinical examination for knee instability. The positions and motions induced were measured in right-left cadaveric knees by a three-dimensional instrumented spacial linkage. We compared the clinicians’ estimate of knee motion limits and subluxations with the actual measured values. Before and after the clinicians’ examination, the three-dimensional limits of knee motion were measured in the knees in the laboratory under defined loading conditions. Also, in one knee, the ACL and superficial medial collateral ligament were cut and the examiners, none of whom were informed of the sectioning, were asked to arrive at a diagnosis. The results for all of the clinical instability tests were similar. There was wide variability between examiners in the starting position of knee flexion and tibial rotation and in the amount of tibial translation and rotation induced. Although some examiners displaced the knee to the maximal displacement limits obtained in the laboratory, others did not, by a substantial margin. This suggests a wide variation in the loads applied by examiners to the knee joint during the tests. For the overall series of clinical tests, only 6 of 11 examiners estimated the amount of AP displacement, tibial rotat Address correspondence and repnnt requests to Frank R Deaconess Hospital, 311 Straight Street, Cincinnati, OH 45219
examiners sectioned
tures.
We concluded that 1) examination test techniques must be standardized as to test conditions so that
clinicians conduct similar tests; 2) comparisons among clinicians in quantitating knee motion limits may be invalid because of the wide variations that occur; 3) instrumented teaching models should be developed to increase interexaminer clinical test reproducibility; 4) given the variability of examiners’ estimates, reliable joint arthrometer or stress radiography test methods should be developed and considered a requirement for reporting clinical results; and 5) the diagnosis of rotatory subluxations is highly subject to diagnostic error and requires a careful assessment of the anterior-posterior position of the medial and lateral tibial plateaus relative to the femur.
Kinematic and biomechanical studies have revealed the knee joint and the joint that has sustained ligamentous injuries.1, 2, 7-12, 14 18, 27, 29 Studies&dquo;, 11 22 have shown that knee ligament injuries can be described by the increased limits of motion 21 for one or more of the six degrees of freedom (flexion-extension, internalexternal tibial rotation, abduction-adduction, medial-lateral joint space opening, anterior-posterior displacement, and compression-distraction) and by the anterior-posterior ab-
complexity of both the normal
Noyes, MD, 163
164
normal position (subluxation) of the medial and lateral tibial plateaus relative to the femur.&dquo; Laboratory studies involving selective ligament sectioning in cadaveric knees have provided useful in vitro information for diagnosing ligamentous and capsular injuries.1, 7-12, 14 16, 18, 27, 29 This in vitro information has indicated the importance, during clinical examination, of prepositioning the joint and applying joint displacement forces that allow testing of the primary and secondary restraints.’o Within the
past few years, instrumented clinical devices have been to obtain more reliable data in quantitating abnormal knee motion limits.3-5, 16, 24-26 These devices appear to be an asset in reporting clinical results, although reproducibility issues still need to be addressed. Several characteristics of the injured knee joint complicate the process of correctly diagnosing a ligament injury. First, after a ligament injury, one or more knee motion limits may be abnormally increased. A combination of ligament injuries may abnormally affect several of the motion limits. Moreover, with abnormally increased motion limits, the knee joint may subluxate into one or more abnormal positions, depending on how the clinical instability tests are conducted.’, &dquo;, 11, 2’ Finally, it may prove difficult for the clinician to quantitate the amount of anterior or posterior displacement or internal or external tibial rotation in terms of the starting and ending positions of the clinical instability tests. Currently, most clinicians would agree that it is difficult to reproduce one another’s clinical examinations. Clinicians use certain examination techniques to arrive at diagnoses that are often of a qualitative, rather than quantitative, nature. Two questions are particularly pertinent: 1) Do clinicians perform the same type of clinical instability tests? 2) Is it feasible to compare the results of instability tests among clinicians or are the results so unique to each examiner that comparisons are not valid? The problem in the qualitative assessment of knee instability is that the examination does not lend itself to reproducibility among examiners nor to accurate documentation in measurable units. The International Knee Documentation Committee (IKDC), formed under the auspices of the American Orthopaedic Society for Sports Medicine (AOSSM) and the European Society of Knee Surgery and Arthroscopy (ESKA), met in July 1988, in Jackson Hole, Wyoming, to seek a consensus on the diagnosis and understanding of knee ligament disorders. (See Table 1, page 140 for committee members.) Eleven clinicians examined two cadaveric knees that were instrumented with a spatial linkage device that allows the three-dimensional position and motions of the knee joint to be measured. We recorded each examiner’s estimate of motion limits and subluxations and then compared their results to the actual measurements determined by the instrumented spatial linkage (ISL). Specific ligaments were then cut in one cadaveric knee and each examiner was asked to provide an injury diagnosis based on his examination. The overall goal of this study was to identify differences in test techniques (starting knee position, motions, motion limits, subluxations) among clinicians and to determine how
developed
accurately clinicians estimate the actual knee displacement. We also wished to determine the ability of the clinician to diagnose a specific ligamentous injury to a knee in which there were multiple abnormal motion limits.
MATERIALS AND METHODS We used a pair of right-left limbs obtained from a single donor in order to allow comparisons between the normal, noninvolved knee and the involved (ligament-sectioned) knee. The limbs were examined and proved to be free of any detectable ligamentous injury or joint disease before testing. Dissection of the knee joints after testing showed no meniscal injury or intraarticular abnormality that could have affected the results of the study. We selectively sectioned ligaments in the right limb and used the left limb as the intact control. An ISL was mounted to blocks attached rigidly to the tibia and femur. In the Cincinnati laboratory, we measured in both cadaveric limbs the limits to anteriorposterior displacement, internal-external rotation, and medial-lateral joint space opening using previously reported methods.’,’o ...... Limits of motion were measured in the limb in the intact state and after cutting the ACL and medial collateral ligament (MCL) (superficial long fibers of the MCL3°) at the joint line. No cuts were made to capsular structures with the exception of a 3 cm medial parapatellar incision made to enter the joint and cut the ACL, after which we repaired the arthrotomy site with sutures. We made additional incisions about the knee to conceal whether medial or lateral ligaments had been cut, then closed the incisions with sutures. The loads applied to the knee joint during the limit tests in the laboratory were as follows: 100 N for measuring AP displacement, 5 Nm for measuring internal-external tibial rotation, and 20 Nm for measuring medial-lateral joint space openings. The measurements were made from 0° to 90° of knee flexion. All measurements were made using a LabMaster (Scientific Solutions, Inc, Solon, OH) data acquisition board and an IBM AT personal computer. Each day before testing, the system was calibrated by placing the ISL into a series of known orientations and positions and then using a nonlinear, least-squares optimization algorithm to minimize error in the measured position and the actual position by adjustment of the 30 parameters used in the transformation from one coordinate system to the other. 27 To simulate examination conditions at the Jackson Hole facility, we replaced the femoral head of both femurs with a ball and socket joint that was attached to the examination table. This allowed a normal range of hip motion and facilitated the clinical examination of the knee joint. Each examiner was given a list of the standard clinical tests and was asked to perform the tests necessary to diagnose the injury. The clinical tests and the test technique were discussed ahead of time by the examiners and a consensus was obtained as to the manner in which the clinical tests would be conducted. The tests included: AP displacement tests as
165
the medial-lateral joint space opening, and internal-external tibial rotation tests to detect any abnormal increases in tibial rotation and to diagnose tibiofemoral subluxations.&dquo; The sequence of tests was chosen by the examiner and both knees were examined. Examiners were asked to place the knee in the starting position, perform the test, and then hold the knee in the maximally displaced position. We measured the starting and maximally displaced position with the ISL and recorded the examiner’s estimate of the absolute amount of displacement. All examiners completed the tests and provided interpretable data except for three examiners performing the internalexternal rotation tests, and one examiner performing the Lachman test. In the latter case, the data were not interpretable because of errors in data collection, or the test was not
completed.
After all of the clinical tests were completed, the soft tissues were removed from the limbs and the ISL was used to digitize the positions of several bony landmarks on each bone. These points were used to determine a Cartesian coordinate system in each bone&dquo; and the coordinate transformation from the bone coordinate system to the ISL mounting block. In designing this study we were aware of a potential problem that the examiner would have in placing his hands about the knee without interfering with the ISL. All examiners became familiar with the presence of the linkage system and were able to conduct the clinical tests without interfering with the ISL. An observer watched the clinical tests to verify that each examiner was able to conduct the tests without limitations.
RESULTS
Figure 1. The bars show the ISL measured values for anterior and postenor displacement for each examiner with starting positions indicated by a solid white circle. The numbers above and below each bar give the measured displacement and the examiner estimated values are given in the parenthesis. Starting position flexion angles and the coupled external rotation for the anterior displacement test are given for each examiner.
Table 1
lists, for each examiner, the diagnoses of ligament Nine of the 11 examiners correctly diagnosed the injury. complete tear of both the ACL and the MCL. A number of examiners diagnosed tears to ligaments that were not injured, including one who diagnosed a complete tear of the posterior cruciate ligament. Seven of 11 examiners appeared TABLE 1 of ligament
Diagnoses
injury’
Figure 2. The curves show the limits of anterior and posterior displacement (vertical axis) when a 100 N anterior or posterior force was applied to the knee for both the intact and ligament-
&dquo;
C, Diagnosed complete tear; P, diagnosed partial tear. PCL, posterior cruciate ligament; LCL, lateral collateral ligament ; ITB, iliotibial band; POP, popliteal ligament; PLC, posterolateral capsule; ARC, arcuate complex; AMC, anteromedial capsule; PMC, posteromedial capsule; POL, posterior oblique ligament. h
sectioned state. The circles represent individual examiner final positions for the anterior displacement test on the ACL/MCLsectioned knee. The squares represent individual examiner final positions for the posterior displacement test on the ACL/ MCL-sectioned knee. The postenor cut curve is the postenor displacement limit obtained in the ACL/MCL-sectioned knee which was the same limit as in the intact state.
166
Figure 3. The bars show the ISL measured values for the examiner-induced internal and external rotation forces for the ligament-sectioned knee. The starting positions for the test are indicated by a solid white circle. The numbers above and below each bar give the measured displacement and examiner estimated values are given in the parentheses. Starting position flexion angles and the coupled antenor displacement for the external rotation test are given for each examiner.
Figure 5. The bars show the ISL measured values for medial and lateral joint space opening in the abduction-adduction rotation test for each examiner. The starting positions are indicated by a solid white circle. The numbers above and below each bar give the measured displacement and the estimated values for each examiner are given in parentheses. Starting position flexion angles, coupled antenor tibial displacement, and the coupled external rotation for the abduction rotation test are given for each examiner.
Figure 4. The curves show the limits of internal and external rotation (vertical axis) when a 5 Nm external and internal torque was applied to the knee for both the intact and sectioned state. The circles represent individual examiner final positions for the external rotation test on the ACL/MCLsectioned knee. The squares represent individual examiner final positions for the internal rotation test on the ACL/MCLsectioned knee.
have misinterpreted the increase in external tibial rotation as an injury to the posterolateral ligamentous complex rather than to the MCL.4This means that they experienced difficulty in defining the position of the tibial plateaus relative to the femur, namely in detecting the anterior subluxation of the medial tibial plateau and absent posterior subluxation of the lateral tibial plateau. Had the examiners to
Figure 6. The
show the limits of medial and lateral a 20 Nm force was to the knee for both the intact and sectioned state. applied The circles represent individual examiner final positions for the medial test on the ACL/MCL-sectioned knee. The squares represent individual examiner final positions for the lateral test on the ACL/MCL-sectioned knee. curves
joint space opening (vertical axis) when
167
TABLE 2 Differences between estimates and measured
TABLE 3
*
displacements*
168
duced
by the examiners showed large variations (range,
7.1
to 16.1 mm; mean, 11.0 mm). The posterior displacement test yielded similar findings (Fig. 1). Figure 2 shows the limits to anterior displacement for both the intact and ACL/MCL-sectioned states as deter-
mined by the ISL. The circles show the maximum displaced tibial positions reached by each examiner. Most examiners reached a position close to the one we found when a 100 N anterior force was applied in the laboratory. No examiner reached the posterior limit that we measured in the laboratory with a 100 N posterior force. Internal-external rotation
Figure 7. External rotation test in the uninjured knee (A) and after sectioning the ACL and MCL (B). The increase in external tibial rotation is shown (7° to 16°). The figures show the increase in anterior displacement of the medial tibial plateau and the lateral shift in the axis of tibial rotation.
The data for the internal and external rotation tests of the ACL/MCL cut knee are shown in Figure 3. We found large differences among examiners in the amount of internal and external tibial rotation induced during testing. Six of the eight examiners (three of the examiners did not provide interpretable data) estimated the total amount of internal rotation to within 5° of that actually measured. However, for external tibial rotation, there were large differences between the actual and estimated amounts, and only one examiner estimated the external tibial rotation to within 5° of the actual values. The starting position for tibial rotation and the flexion angle of the test also varied widely. For example, the range of knee flexion varied from 1.9° to 35.3°. Figure 4, which depicts the internal and external rotation limit curves for both the intact and ACL/MCL-sectioned state, shows that each examiner performed the test at a different flexion angle and reached a different final rotation position. Note that only three examiners supplied torque sufficient to approximate the abnormal limit of external rotation when the ACL and MCL were cut. Medial-lateral
been able to detect the correct position, they would have excluded injury to the lateral collateral ligament and pos-
terolateral
ligament complex.
Anterior-posterior displacement Figure 1 show the amount of anterior or posterior displacement during the Lachman test18 as measured with the ISL in the ACL/MCL cut knee. A solid white circle within the bars indicates the starting position. The vertical columns list the differences between the measured and estimated values for the Lachman test for The black and gray bars in
each examiner. Three examiners estimated the amount of anterior displacement to within 2 mm of the measured value. The estimates of five others were between 2 and 4 mm of the measured value, and two examiners’ estimates were over 5 mm. The starting flexion angle position for the knee varied
(Fig. 1). Eight of 10 examiners allowed less than 5° of coupled tibial rotation during the test. The anterior tibial displacement inwidely
among
examiners, from 2.6°
joints space opening
In the testing for medial and lateral joint space opening, each examiner was asked to start the test with the femoral condyle in contact with the tibial plateau for the abduction and adduction rotation tests. For the medial joint space opening abduction test, 8 of 11 examiners were within 3 mm for the difference between their estimated and measured values, 2 were between 3 and 5 mm, and one examiner differed by 9.3 mm (Fig. 5). The starting flexion angle position ranged from 3.1° to 21.3° (mean, 11.6°). In Figure 6, the medial and lateral joint space opening limits are given for the intact and ACL/MCL-sectioned states. The data show that each examiner performed the tests at a different flexion angle and reached a different final tibiofemoral position. Some examiners reached the amount of joint space opening we measured under an applied load of 20 Nm, whereas other examiners induced both less and more joint space opening. Involved knee
versus
noninvolved knee differences
to 25.1°
We evaluated the data from each test in order to analyze the difference between the values of the ligament-sectioned
169
state and the intact state as
as estimated by the examiners and measured by the ISL (Table 2). Three examiners were
within 2
of the measured difference for the Lachman were within 5° of the measured difference for the external rotation test. Results for the medial-lateral joint space opening tests were better. The estimates of 8 of 11 examiners were within 3 mm of the measured amount of medial joint opening; 9 of 11 examiners estimated the amount of lateral joint space opening to within 3 mm of the actual value. test.
mm
Only
two examiners
Medial-lateral compartment translations rotation
during external tibial
External tibial rotation increased from 17.8° in the intact knee to 22. l’after cutting the ACL and MCL. Table 3 shows the millimeters of anterior displacement for the medial, central, and lateral tibial plateau reference points during the external rotation tests. The medial and lateral reference points were located at the midportion of each respective compartment (25% and 75% tibial width) and the central point was located between the spines of the intercondylar eminence. Six of the eight examiners had an increase in anterior translation of the medial tibial plateau during the external rotation test. The displacement of the medial and lateral tibial plateaus is shown for the intact state and injured state in Figure 7. The average center of tibial rotation was in the lateral tibiofemoral compartment for both the intact and injured limb. In Figure 7B, the lateral shift in the axis of tibial rotation is apparent along with the increase in anterior displacement of the medial tibial plateau. Note that the anterior displacement of the medial tibial plateau increased from 3.0 to 8.5 mm (Table 3). In terms of the previously presented data on clinical diagnoses, 7 of the 11 examiners erroneously diagnosed injury to the posterolateral structures, even though the lateral plateau did not displace further posteriorly.
DISCUSSION For each clinical test, our results reveal a large variation between examiners in how the tests are performed and the amount of displacement induced. For the AP displacement tests, the starting position of the knees varied widely, as did the total amount of anterior displacement induced. The range of anterior tibial displacement varied from 7 to 16 mm among clinicians. The difference in the total amount of AP displacement probably reflects both the difference in starting positions of knee flexion (and thus the anterior and posterior limits of AP displacement) and the loads applied by the examiner. Regarding the examiners’ ability to estimate the differences between the intact and the ligamentsectioned states for the anterior displacement test, our results showed that only 3 of 11 examiners were within 2 mm of the measured difference between limbs. Not surprisingly, those who more accurately estimated the amount of anterior
displacement for the injured limb
were able to more closely estimate the difference between limbs. For the internal and external tibial rotation tests, there was a large variation in starting position used by examiners and in the degrees of tibial rotation they induced. Several factors are likely responsible for variations in these test results. The examiners probably were applying different amounts of torque during the test. More than half of the examiners did not reach the limits of either external rotation or internal rotation obtained under the laboratory conditions of a 5 Nm torque. The tests for medial-lateral joint space opening also revealed a wide variation in the starting position. Some examiners started with an initial closed position of the medial and lateral tibiofemoral compartment before the test, whereas others did not. Only from the closed starting position of tibiofemoral contact can an examiner accurately estimate the amount of joint space opening. Failure to obtain the closed position initially for either the medial or lateral tibiofemoral compartment would be expected to result in a misinterpretation of the amount of joint space opening. Despite the variations in estimated displacements on the clinical tests, 9 of the 11 examiners correctly diagnosed the ACL and superficial MCL injury. However, there were numerous errors in diagnoses of injury to other ligament structures. The most significant error in diagnosis was the interpretation of an increase in external tibial rotation as a posterior subluxation of the lateral tibial plateau, therefore resulting in the diagnosis of injury to the posterolateral ligament complex. The abnormality detected was actually an anterior subluxation of the medial tibial plateau, caused by sectioning the ACL and MCL. To avoid this misdiagnosis, it is necessary to carefully palpate the medial and lateral tibial plateaus and their position relative to the femoral condyle in the maximum position of external and internal tibial rotation.2o,23 In many knees, it is often impossible to palpate with certainty the position of the tibial plateaus, making the correct diagnosis of a rotatory subluxation impossible. This seems to indicate the need for future studies to help develop instrumented or radiographic methods to diagnose more accurately the complex rotatory subluxations of the knee joint. Overall, our results show that half of the examiners (D, E, F, G, H, and I, Table 2), were able to estimate two of three of the clinical tests within the error bounds of 2 mm for AP displacement, 5° for internal-external rotation, and 3 mm for medial joint space opening. These results suggest that clinicians’ examination skills differ widely for quantification of joint motion limits and tibiofemoral subluxations. We recommend that a more standardized test technique be agreed upon for all of the tests, especially with regard to the starting position of knee flexion and tibial rotation and how the test is performed. The initial starting position of the test, as regards degrees of knee flexion and tibial rotation, strongly controls the absolute limits of motion that can be obtained and is one of the easiest variables to control.
Furthermore,
we
recommend that instrumented models be
170
developed to train clinicians in testing techniques, proper starting positions, application of uniform forces, and estimation of joint displacements. Studies are necessary to determine clinicians’ reproducibility for tests and whether acceptable estimates of knee motion limits are possible in
Sportsmedicine and Orthopaedic Research and Education Foundation.
REFERENCES
the clinical examination. Butler DL, Noyes FR, Grood ES. Ligamentous restraints to anteriorposterior drawer in the human knee. A biomechanical study J Bone Joint Surg 62A 259-270, 1980 2 Chambat P Les Ruptures Isolees Du L.P.M., in Trillat A, Dejar H, Bousquet G (eds). Chirurgie du Genou 3 emes Journees Lyon Septembre 77 Simep, Villeurbanne cedex, 1978 3 Daniel DM, Malcom LL, Losse LG, et al Instrumented measurement of anterior laxity of the knee J Bone Joint Surg 67A. 720-726, 1985 4 Daniel DM, Stone ML, Sachs R, et al Instrumented measurement of anterior knee laxity in patients with acute anterior cruciate ligament disruption Am J Sports Med 13. 401-407, 1985 5 Edixhoven P, Huiskes R, de Graaf R, et al. Accuracy and reproducibility of instrumented knee-drawer tests J Orthop Res 5: 378-387, 1987 6 Feagin JA, Blake WP Postoperative evaluation and result recording in the anterior cruciate ligament reconstructed knee Clin Orthop 172 143-147, 1
CONCLUSIONS 1. In the AP displacement tests, the examiners showed similarities in restraining the amount of coupled tibial rotation. However, large discrepancies existed in the initial starting position and the millimeters of displacement induced and the ability to estimate the amount of anterior
displacement. 2. In the internal-external rotation tests, the examiners showed large variations in the starting position, degrees of rotation induced, and ability to estimate the amount of tibial rotation, particularly external tibial rotation. 3. In the medial-lateral joint space opening tests, the examiners showed large variations in the initial starting position and millimeters of joint space opening induced. The examiners did show similarities in restraining the amount of coupled internal and external tibial rotation while performing the abduction and adduction rotation tests. 4. In the overall series of instability tests performed, only 6 of 11 examiners estimated (at least 67% of the time) the amount of AP displacement, tibial rotation, and medial and lateral joint space opening within range of 2 mm, 5°, and 3 mm,
respectively.
5. A majority of the examiners diagnosed the complete tear of the ACL and the superficial medial collateral ligament ; however, numerous incorrect diagnoses of tears to other ligaments were made. The most common error in diagnosing ligament injury was to mistake the increased external tibial rotation after ACL and medial collateral ligament sectioning as an indication of injury to the posterolateral ligament complex. 6. The diagnosis of the type of rotatory subluxation, when increases in tibial rotation occur after ligament injury, involves the difficulty of separating anterior-posterior subluxation of the medial tibial plateau from anterior-posterior
subluxation of the lateral tibial plateau. 7. Reliable joint arthrometer and/or stress radiography measurements should be developed as many variations of
clinicians’ diagnoses of joint motion limits and subluxations may invalidate conclusions of joint stability after surgery.
1983
Fukubayashi T, Torzilli PA, Sherman MF, et al: An in vitro biomechanical evaluation of anterior-posterior motion of the knee. Tibial displacement, rotation, and torque J Bone Joint Surg 64A. 258-264, 1982 8 Gollehon DL, Torzilli PA, Warren RF The role of the posterolateral and cruciate ligaments in the stability of the human knee A biomechanical study J Bone Joint Surg 69A. 233-242, 1987 9 Grood ES, Noyes FR Diagnosis and classification of knee ligament injuries: PartI Biomechanical precepts, in Feagin J Jr (ed). Crucial Ligament Injuries New York, Churchill Livingstone, 1987, pp 245-260 10 Grood ES, Noyes FR, Butler DL, et al. Ligamentous and capsular restraints preventing straight medial and lateral laxity in intact human cadaver knees . 1257-1269, 1981 J Bone Joint Surg 63A 11 Grood ES, Stowers SF, Noyes FR. Limits of movement in the human knee Effect of sectioning the posterior cruciate ligament and posterolateral structures J Bone Joint Surg 70A. 88-97, 1988 12 Grood ES, Suntay WJ A joint coordinate system for the clinical description of three-dimensional joint motion. Application to the knee J Biomech Eng 7
105 136-144,1983 13 Jakob RP, Staubli HU, Deland JT Grading the pivot shift Objective tests with implications for treatment. J Bone Joint Surg 69B. 294-299, 1987 14 Levy IM, Torzilli PA, Warren RF The effect of medial meniscectomy on anterior-posterior motion of the knee J Bone Joint Surg 64A 883-888, 1982 15. Markolf KL, Graff-Radford A, Amstutz HC In vivo knee stability. A quantitative assessment using an instrumented clinical testing apparatus J Bone Joint Surg 60A 664-674, 1978 16. Markolf KL, Mensch JS, Amstutz HC. Stiffness and laxity of the knee— the contributions of the supporting structures A quantitative in vitro study J Bone Joint Surg 58A 583-594, 1976 17. Mueller W The Knee—Form, Function, and Ligament Reconstruction Berlin, Springer-Verlag, 1982 18. Nielsen S, Kromann-Anderson C, Rasmussen O, et al: Instability of cadaver knees after transection of capsule and ligaments Acta Orthop Scand 55
30-34,1984 Noyes FR, Grood ES. Classification of ligament injuries. Why an anterolateral laxity or anteromedial laxity is not a diagnostic entity Instr Course Lect XXXVI. 185-200, 1987 20 Noyes FR, Grood ES Diagnosis and classification of knee ligament injuries: Part II. Clinical concepts in Feagin J. Jr (ed) Crucial Ligament Inluries. New York, Churchill Livingstone, 1987, pp 261-285 21. Noyes FR, Grood ES, Butler DL, et al. Clinical laxity tests and functional stability of the knee Biomechanical concepts. Clin Orthop 146 84-89, 19
1980 Grood ES, Suntay WJ, et al. The three-dimensional laxity of the anterior cruciate deficient knee as determined by clinical laxity tests lowa Orthop J 3. 32-44, 1983 23 Noyes FR, Grood ES, Torzilli PA Current concepts review. The definitions of terms for motion and position of the knee and injuries of the ligaments J Bone Joint Surg 71A. 465-472, 1989 24 Oliver JH, Coughlin LP Objective knee evaluation using the Genucom knee analysis system Clinical implications Am J Sports Med 15 571-578, 1987 25. Shino K, Inoue M, Honbe S, et al. Measurement of anterior instability of the knee. A new apparatus for clmical testing. J Bone Joint Surg 69B 22.
ACKNOWLEDGMENTS We are
grateful to the International Knee Documentation Committee for permitting and assisting us in conducting the experiments reported here. This work was supported in part by Grant AR-21172 from the National Institute of Arthritis, Musculoskeletal and Skin Diseases, and the Cincinnati
Noyes FR,
608-613,1987
171 26 Steiner ME, Brown CH, Zarins B. Knee laxity testing instrumented devices and the clinical exammation
Comparison of (abstract) Orthop Trans
13 502, 1989 Grood ES, Hefzy MS, et al Error analysis of a system for measuring three dimensional joint motion J Biomech Eng 105 127-135, 1983 28 Torg JS, Conrad W, Kalen V. Clinical diagnosis of anterior cruciate ligament instablity in the athlete. Am J Sports Med 4. 84-93, 1976 27
Suntay WJ,
29 Torzilli PA, Greenberg RL, Insall J: An in vivo biomechanical evaluation of the anterior-posterior motion of the knee Roentgenographic measurement technique, stress machine, and stable population. J Bone Joint Surg 63A:
960-968,1981 30 Warren LF, Marshall JL The supporting structures and layers on the medial side of the knee. An anatomical analysis J Bone Joint Surg 61A.
56-62,1979
The
diagnosis
FRANK R.
NOYES,*† MD, JOHN
F. CUMMINGS,‡ MS, EDWARD S. GROOD,‡ PhD, KIMBERLY A. WALZ-HASSELFELD,* AND RANDALL R. WROBLE,* MD
From the *Cincinnati Sportsmedicine and Orthopaedic Center, The Deaconess Hospital, Cincinnati, Ohio, and the ‡Noyes-Giannestras Biomechanics Laboratories, Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, Ohio
tion, and medial-lateral joint space opening within the
ABSTRACT
limits defined in the study. Nine of the 11 correctly diagnosed the instability in the ligaments; there were numerous errors in diagnosis of injury to other ligament structures. The most frequent misdiagnosis (7 of 11 examiners) was the interpretation of the increased external tibial rotation in the ligament-sectioned knee as representing an injury to the posterolateral ligament structures where, in fact, the injury was to the ACL and medial ligament struc-
acceptable
The clinical diagnosis of knee ligament injuries requires the clinician to: 1) estimate the abnormal motion limits that occur in one or more of the six degrees of freedom that comprise three-dimensional motion; 2) determine the abnormal position (subluxation) of the medial and lateral tibiofemoral compartments; and 3) precisely define the anatomical structures injured and degree of that injury. To determine the clinician’s ability to perform these tasks, we evaluated 11 knee surgeons’ clinical examination for knee instability. The positions and motions induced were measured in right-left cadaveric knees by a three-dimensional instrumented spacial linkage. We compared the clinicians’ estimate of knee motion limits and subluxations with the actual measured values. Before and after the clinicians’ examination, the three-dimensional limits of knee motion were measured in the knees in the laboratory under defined loading conditions. Also, in one knee, the ACL and superficial medial collateral ligament were cut and the examiners, none of whom were informed of the sectioning, were asked to arrive at a diagnosis. The results for all of the clinical instability tests were similar. There was wide variability between examiners in the starting position of knee flexion and tibial rotation and in the amount of tibial translation and rotation induced. Although some examiners displaced the knee to the maximal displacement limits obtained in the laboratory, others did not, by a substantial margin. This suggests a wide variation in the loads applied by examiners to the knee joint during the tests. For the overall series of clinical tests, only 6 of 11 examiners estimated the amount of AP displacement, tibial rotat Address correspondence and repnnt requests to Frank R Deaconess Hospital, 311 Straight Street, Cincinnati, OH 45219
examiners sectioned
tures.
We concluded that 1) examination test techniques must be standardized as to test conditions so that
clinicians conduct similar tests; 2) comparisons among clinicians in quantitating knee motion limits may be invalid because of the wide variations that occur; 3) instrumented teaching models should be developed to increase interexaminer clinical test reproducibility; 4) given the variability of examiners’ estimates, reliable joint arthrometer or stress radiography test methods should be developed and considered a requirement for reporting clinical results; and 5) the diagnosis of rotatory subluxations is highly subject to diagnostic error and requires a careful assessment of the anterior-posterior position of the medial and lateral tibial plateaus relative to the femur.
Kinematic and biomechanical studies have revealed the knee joint and the joint that has sustained ligamentous injuries.1, 2, 7-12, 14 18, 27, 29 Studies&dquo;, 11 22 have shown that knee ligament injuries can be described by the increased limits of motion 21 for one or more of the six degrees of freedom (flexion-extension, internalexternal tibial rotation, abduction-adduction, medial-lateral joint space opening, anterior-posterior displacement, and compression-distraction) and by the anterior-posterior ab-
complexity of both the normal
Noyes, MD, 163
164
normal position (subluxation) of the medial and lateral tibial plateaus relative to the femur.&dquo; Laboratory studies involving selective ligament sectioning in cadaveric knees have provided useful in vitro information for diagnosing ligamentous and capsular injuries.1, 7-12, 14 16, 18, 27, 29 This in vitro information has indicated the importance, during clinical examination, of prepositioning the joint and applying joint displacement forces that allow testing of the primary and secondary restraints.’o Within the
past few years, instrumented clinical devices have been to obtain more reliable data in quantitating abnormal knee motion limits.3-5, 16, 24-26 These devices appear to be an asset in reporting clinical results, although reproducibility issues still need to be addressed. Several characteristics of the injured knee joint complicate the process of correctly diagnosing a ligament injury. First, after a ligament injury, one or more knee motion limits may be abnormally increased. A combination of ligament injuries may abnormally affect several of the motion limits. Moreover, with abnormally increased motion limits, the knee joint may subluxate into one or more abnormal positions, depending on how the clinical instability tests are conducted.’, &dquo;, 11, 2’ Finally, it may prove difficult for the clinician to quantitate the amount of anterior or posterior displacement or internal or external tibial rotation in terms of the starting and ending positions of the clinical instability tests. Currently, most clinicians would agree that it is difficult to reproduce one another’s clinical examinations. Clinicians use certain examination techniques to arrive at diagnoses that are often of a qualitative, rather than quantitative, nature. Two questions are particularly pertinent: 1) Do clinicians perform the same type of clinical instability tests? 2) Is it feasible to compare the results of instability tests among clinicians or are the results so unique to each examiner that comparisons are not valid? The problem in the qualitative assessment of knee instability is that the examination does not lend itself to reproducibility among examiners nor to accurate documentation in measurable units. The International Knee Documentation Committee (IKDC), formed under the auspices of the American Orthopaedic Society for Sports Medicine (AOSSM) and the European Society of Knee Surgery and Arthroscopy (ESKA), met in July 1988, in Jackson Hole, Wyoming, to seek a consensus on the diagnosis and understanding of knee ligament disorders. (See Table 1, page 140 for committee members.) Eleven clinicians examined two cadaveric knees that were instrumented with a spatial linkage device that allows the three-dimensional position and motions of the knee joint to be measured. We recorded each examiner’s estimate of motion limits and subluxations and then compared their results to the actual measurements determined by the instrumented spatial linkage (ISL). Specific ligaments were then cut in one cadaveric knee and each examiner was asked to provide an injury diagnosis based on his examination. The overall goal of this study was to identify differences in test techniques (starting knee position, motions, motion limits, subluxations) among clinicians and to determine how
developed
accurately clinicians estimate the actual knee displacement. We also wished to determine the ability of the clinician to diagnose a specific ligamentous injury to a knee in which there were multiple abnormal motion limits.
MATERIALS AND METHODS We used a pair of right-left limbs obtained from a single donor in order to allow comparisons between the normal, noninvolved knee and the involved (ligament-sectioned) knee. The limbs were examined and proved to be free of any detectable ligamentous injury or joint disease before testing. Dissection of the knee joints after testing showed no meniscal injury or intraarticular abnormality that could have affected the results of the study. We selectively sectioned ligaments in the right limb and used the left limb as the intact control. An ISL was mounted to blocks attached rigidly to the tibia and femur. In the Cincinnati laboratory, we measured in both cadaveric limbs the limits to anteriorposterior displacement, internal-external rotation, and medial-lateral joint space opening using previously reported methods.’,’o ...... Limits of motion were measured in the limb in the intact state and after cutting the ACL and medial collateral ligament (MCL) (superficial long fibers of the MCL3°) at the joint line. No cuts were made to capsular structures with the exception of a 3 cm medial parapatellar incision made to enter the joint and cut the ACL, after which we repaired the arthrotomy site with sutures. We made additional incisions about the knee to conceal whether medial or lateral ligaments had been cut, then closed the incisions with sutures. The loads applied to the knee joint during the limit tests in the laboratory were as follows: 100 N for measuring AP displacement, 5 Nm for measuring internal-external tibial rotation, and 20 Nm for measuring medial-lateral joint space openings. The measurements were made from 0° to 90° of knee flexion. All measurements were made using a LabMaster (Scientific Solutions, Inc, Solon, OH) data acquisition board and an IBM AT personal computer. Each day before testing, the system was calibrated by placing the ISL into a series of known orientations and positions and then using a nonlinear, least-squares optimization algorithm to minimize error in the measured position and the actual position by adjustment of the 30 parameters used in the transformation from one coordinate system to the other. 27 To simulate examination conditions at the Jackson Hole facility, we replaced the femoral head of both femurs with a ball and socket joint that was attached to the examination table. This allowed a normal range of hip motion and facilitated the clinical examination of the knee joint. Each examiner was given a list of the standard clinical tests and was asked to perform the tests necessary to diagnose the injury. The clinical tests and the test technique were discussed ahead of time by the examiners and a consensus was obtained as to the manner in which the clinical tests would be conducted. The tests included: AP displacement tests as
165
the medial-lateral joint space opening, and internal-external tibial rotation tests to detect any abnormal increases in tibial rotation and to diagnose tibiofemoral subluxations.&dquo; The sequence of tests was chosen by the examiner and both knees were examined. Examiners were asked to place the knee in the starting position, perform the test, and then hold the knee in the maximally displaced position. We measured the starting and maximally displaced position with the ISL and recorded the examiner’s estimate of the absolute amount of displacement. All examiners completed the tests and provided interpretable data except for three examiners performing the internalexternal rotation tests, and one examiner performing the Lachman test. In the latter case, the data were not interpretable because of errors in data collection, or the test was not
completed.
After all of the clinical tests were completed, the soft tissues were removed from the limbs and the ISL was used to digitize the positions of several bony landmarks on each bone. These points were used to determine a Cartesian coordinate system in each bone&dquo; and the coordinate transformation from the bone coordinate system to the ISL mounting block. In designing this study we were aware of a potential problem that the examiner would have in placing his hands about the knee without interfering with the ISL. All examiners became familiar with the presence of the linkage system and were able to conduct the clinical tests without interfering with the ISL. An observer watched the clinical tests to verify that each examiner was able to conduct the tests without limitations.
RESULTS
Figure 1. The bars show the ISL measured values for anterior and postenor displacement for each examiner with starting positions indicated by a solid white circle. The numbers above and below each bar give the measured displacement and the examiner estimated values are given in the parenthesis. Starting position flexion angles and the coupled external rotation for the anterior displacement test are given for each examiner.
Table 1
lists, for each examiner, the diagnoses of ligament Nine of the 11 examiners correctly diagnosed the injury. complete tear of both the ACL and the MCL. A number of examiners diagnosed tears to ligaments that were not injured, including one who diagnosed a complete tear of the posterior cruciate ligament. Seven of 11 examiners appeared TABLE 1 of ligament
Diagnoses
injury’
Figure 2. The curves show the limits of anterior and posterior displacement (vertical axis) when a 100 N anterior or posterior force was applied to the knee for both the intact and ligament-
&dquo;
C, Diagnosed complete tear; P, diagnosed partial tear. PCL, posterior cruciate ligament; LCL, lateral collateral ligament ; ITB, iliotibial band; POP, popliteal ligament; PLC, posterolateral capsule; ARC, arcuate complex; AMC, anteromedial capsule; PMC, posteromedial capsule; POL, posterior oblique ligament. h
sectioned state. The circles represent individual examiner final positions for the anterior displacement test on the ACL/MCLsectioned knee. The squares represent individual examiner final positions for the posterior displacement test on the ACL/ MCL-sectioned knee. The postenor cut curve is the postenor displacement limit obtained in the ACL/MCL-sectioned knee which was the same limit as in the intact state.
166
Figure 3. The bars show the ISL measured values for the examiner-induced internal and external rotation forces for the ligament-sectioned knee. The starting positions for the test are indicated by a solid white circle. The numbers above and below each bar give the measured displacement and examiner estimated values are given in the parentheses. Starting position flexion angles and the coupled antenor displacement for the external rotation test are given for each examiner.
Figure 5. The bars show the ISL measured values for medial and lateral joint space opening in the abduction-adduction rotation test for each examiner. The starting positions are indicated by a solid white circle. The numbers above and below each bar give the measured displacement and the estimated values for each examiner are given in parentheses. Starting position flexion angles, coupled antenor tibial displacement, and the coupled external rotation for the abduction rotation test are given for each examiner.
Figure 4. The curves show the limits of internal and external rotation (vertical axis) when a 5 Nm external and internal torque was applied to the knee for both the intact and sectioned state. The circles represent individual examiner final positions for the external rotation test on the ACL/MCLsectioned knee. The squares represent individual examiner final positions for the internal rotation test on the ACL/MCLsectioned knee.
have misinterpreted the increase in external tibial rotation as an injury to the posterolateral ligamentous complex rather than to the MCL.4This means that they experienced difficulty in defining the position of the tibial plateaus relative to the femur, namely in detecting the anterior subluxation of the medial tibial plateau and absent posterior subluxation of the lateral tibial plateau. Had the examiners to
Figure 6. The
show the limits of medial and lateral a 20 Nm force was to the knee for both the intact and sectioned state. applied The circles represent individual examiner final positions for the medial test on the ACL/MCL-sectioned knee. The squares represent individual examiner final positions for the lateral test on the ACL/MCL-sectioned knee. curves
joint space opening (vertical axis) when
167
TABLE 2 Differences between estimates and measured
TABLE 3
*
displacements*
168
duced
by the examiners showed large variations (range,
7.1
to 16.1 mm; mean, 11.0 mm). The posterior displacement test yielded similar findings (Fig. 1). Figure 2 shows the limits to anterior displacement for both the intact and ACL/MCL-sectioned states as deter-
mined by the ISL. The circles show the maximum displaced tibial positions reached by each examiner. Most examiners reached a position close to the one we found when a 100 N anterior force was applied in the laboratory. No examiner reached the posterior limit that we measured in the laboratory with a 100 N posterior force. Internal-external rotation
Figure 7. External rotation test in the uninjured knee (A) and after sectioning the ACL and MCL (B). The increase in external tibial rotation is shown (7° to 16°). The figures show the increase in anterior displacement of the medial tibial plateau and the lateral shift in the axis of tibial rotation.
The data for the internal and external rotation tests of the ACL/MCL cut knee are shown in Figure 3. We found large differences among examiners in the amount of internal and external tibial rotation induced during testing. Six of the eight examiners (three of the examiners did not provide interpretable data) estimated the total amount of internal rotation to within 5° of that actually measured. However, for external tibial rotation, there were large differences between the actual and estimated amounts, and only one examiner estimated the external tibial rotation to within 5° of the actual values. The starting position for tibial rotation and the flexion angle of the test also varied widely. For example, the range of knee flexion varied from 1.9° to 35.3°. Figure 4, which depicts the internal and external rotation limit curves for both the intact and ACL/MCL-sectioned state, shows that each examiner performed the test at a different flexion angle and reached a different final rotation position. Note that only three examiners supplied torque sufficient to approximate the abnormal limit of external rotation when the ACL and MCL were cut. Medial-lateral
been able to detect the correct position, they would have excluded injury to the lateral collateral ligament and pos-
terolateral
ligament complex.
Anterior-posterior displacement Figure 1 show the amount of anterior or posterior displacement during the Lachman test18 as measured with the ISL in the ACL/MCL cut knee. A solid white circle within the bars indicates the starting position. The vertical columns list the differences between the measured and estimated values for the Lachman test for The black and gray bars in
each examiner. Three examiners estimated the amount of anterior displacement to within 2 mm of the measured value. The estimates of five others were between 2 and 4 mm of the measured value, and two examiners’ estimates were over 5 mm. The starting flexion angle position for the knee varied
(Fig. 1). Eight of 10 examiners allowed less than 5° of coupled tibial rotation during the test. The anterior tibial displacement inwidely
among
examiners, from 2.6°
joints space opening
In the testing for medial and lateral joint space opening, each examiner was asked to start the test with the femoral condyle in contact with the tibial plateau for the abduction and adduction rotation tests. For the medial joint space opening abduction test, 8 of 11 examiners were within 3 mm for the difference between their estimated and measured values, 2 were between 3 and 5 mm, and one examiner differed by 9.3 mm (Fig. 5). The starting flexion angle position ranged from 3.1° to 21.3° (mean, 11.6°). In Figure 6, the medial and lateral joint space opening limits are given for the intact and ACL/MCL-sectioned states. The data show that each examiner performed the tests at a different flexion angle and reached a different final tibiofemoral position. Some examiners reached the amount of joint space opening we measured under an applied load of 20 Nm, whereas other examiners induced both less and more joint space opening. Involved knee
versus
noninvolved knee differences
to 25.1°
We evaluated the data from each test in order to analyze the difference between the values of the ligament-sectioned
169
state and the intact state as
as estimated by the examiners and measured by the ISL (Table 2). Three examiners were
within 2
of the measured difference for the Lachman were within 5° of the measured difference for the external rotation test. Results for the medial-lateral joint space opening tests were better. The estimates of 8 of 11 examiners were within 3 mm of the measured amount of medial joint opening; 9 of 11 examiners estimated the amount of lateral joint space opening to within 3 mm of the actual value. test.
mm
Only
two examiners
Medial-lateral compartment translations rotation
during external tibial
External tibial rotation increased from 17.8° in the intact knee to 22. l’after cutting the ACL and MCL. Table 3 shows the millimeters of anterior displacement for the medial, central, and lateral tibial plateau reference points during the external rotation tests. The medial and lateral reference points were located at the midportion of each respective compartment (25% and 75% tibial width) and the central point was located between the spines of the intercondylar eminence. Six of the eight examiners had an increase in anterior translation of the medial tibial plateau during the external rotation test. The displacement of the medial and lateral tibial plateaus is shown for the intact state and injured state in Figure 7. The average center of tibial rotation was in the lateral tibiofemoral compartment for both the intact and injured limb. In Figure 7B, the lateral shift in the axis of tibial rotation is apparent along with the increase in anterior displacement of the medial tibial plateau. Note that the anterior displacement of the medial tibial plateau increased from 3.0 to 8.5 mm (Table 3). In terms of the previously presented data on clinical diagnoses, 7 of the 11 examiners erroneously diagnosed injury to the posterolateral structures, even though the lateral plateau did not displace further posteriorly.
DISCUSSION For each clinical test, our results reveal a large variation between examiners in how the tests are performed and the amount of displacement induced. For the AP displacement tests, the starting position of the knees varied widely, as did the total amount of anterior displacement induced. The range of anterior tibial displacement varied from 7 to 16 mm among clinicians. The difference in the total amount of AP displacement probably reflects both the difference in starting positions of knee flexion (and thus the anterior and posterior limits of AP displacement) and the loads applied by the examiner. Regarding the examiners’ ability to estimate the differences between the intact and the ligamentsectioned states for the anterior displacement test, our results showed that only 3 of 11 examiners were within 2 mm of the measured difference between limbs. Not surprisingly, those who more accurately estimated the amount of anterior
displacement for the injured limb
were able to more closely estimate the difference between limbs. For the internal and external tibial rotation tests, there was a large variation in starting position used by examiners and in the degrees of tibial rotation they induced. Several factors are likely responsible for variations in these test results. The examiners probably were applying different amounts of torque during the test. More than half of the examiners did not reach the limits of either external rotation or internal rotation obtained under the laboratory conditions of a 5 Nm torque. The tests for medial-lateral joint space opening also revealed a wide variation in the starting position. Some examiners started with an initial closed position of the medial and lateral tibiofemoral compartment before the test, whereas others did not. Only from the closed starting position of tibiofemoral contact can an examiner accurately estimate the amount of joint space opening. Failure to obtain the closed position initially for either the medial or lateral tibiofemoral compartment would be expected to result in a misinterpretation of the amount of joint space opening. Despite the variations in estimated displacements on the clinical tests, 9 of the 11 examiners correctly diagnosed the ACL and superficial MCL injury. However, there were numerous errors in diagnoses of injury to other ligament structures. The most significant error in diagnosis was the interpretation of an increase in external tibial rotation as a posterior subluxation of the lateral tibial plateau, therefore resulting in the diagnosis of injury to the posterolateral ligament complex. The abnormality detected was actually an anterior subluxation of the medial tibial plateau, caused by sectioning the ACL and MCL. To avoid this misdiagnosis, it is necessary to carefully palpate the medial and lateral tibial plateaus and their position relative to the femoral condyle in the maximum position of external and internal tibial rotation.2o,23 In many knees, it is often impossible to palpate with certainty the position of the tibial plateaus, making the correct diagnosis of a rotatory subluxation impossible. This seems to indicate the need for future studies to help develop instrumented or radiographic methods to diagnose more accurately the complex rotatory subluxations of the knee joint. Overall, our results show that half of the examiners (D, E, F, G, H, and I, Table 2), were able to estimate two of three of the clinical tests within the error bounds of 2 mm for AP displacement, 5° for internal-external rotation, and 3 mm for medial joint space opening. These results suggest that clinicians’ examination skills differ widely for quantification of joint motion limits and tibiofemoral subluxations. We recommend that a more standardized test technique be agreed upon for all of the tests, especially with regard to the starting position of knee flexion and tibial rotation and how the test is performed. The initial starting position of the test, as regards degrees of knee flexion and tibial rotation, strongly controls the absolute limits of motion that can be obtained and is one of the easiest variables to control.
Furthermore,
we
recommend that instrumented models be
170
developed to train clinicians in testing techniques, proper starting positions, application of uniform forces, and estimation of joint displacements. Studies are necessary to determine clinicians’ reproducibility for tests and whether acceptable estimates of knee motion limits are possible in
Sportsmedicine and Orthopaedic Research and Education Foundation.
REFERENCES
the clinical examination. Butler DL, Noyes FR, Grood ES. Ligamentous restraints to anteriorposterior drawer in the human knee. A biomechanical study J Bone Joint Surg 62A 259-270, 1980 2 Chambat P Les Ruptures Isolees Du L.P.M., in Trillat A, Dejar H, Bousquet G (eds). Chirurgie du Genou 3 emes Journees Lyon Septembre 77 Simep, Villeurbanne cedex, 1978 3 Daniel DM, Malcom LL, Losse LG, et al Instrumented measurement of anterior laxity of the knee J Bone Joint Surg 67A. 720-726, 1985 4 Daniel DM, Stone ML, Sachs R, et al Instrumented measurement of anterior knee laxity in patients with acute anterior cruciate ligament disruption Am J Sports Med 13. 401-407, 1985 5 Edixhoven P, Huiskes R, de Graaf R, et al. Accuracy and reproducibility of instrumented knee-drawer tests J Orthop Res 5: 378-387, 1987 6 Feagin JA, Blake WP Postoperative evaluation and result recording in the anterior cruciate ligament reconstructed knee Clin Orthop 172 143-147, 1
CONCLUSIONS 1. In the AP displacement tests, the examiners showed similarities in restraining the amount of coupled tibial rotation. However, large discrepancies existed in the initial starting position and the millimeters of displacement induced and the ability to estimate the amount of anterior
displacement. 2. In the internal-external rotation tests, the examiners showed large variations in the starting position, degrees of rotation induced, and ability to estimate the amount of tibial rotation, particularly external tibial rotation. 3. In the medial-lateral joint space opening tests, the examiners showed large variations in the initial starting position and millimeters of joint space opening induced. The examiners did show similarities in restraining the amount of coupled internal and external tibial rotation while performing the abduction and adduction rotation tests. 4. In the overall series of instability tests performed, only 6 of 11 examiners estimated (at least 67% of the time) the amount of AP displacement, tibial rotation, and medial and lateral joint space opening within range of 2 mm, 5°, and 3 mm,
respectively.
5. A majority of the examiners diagnosed the complete tear of the ACL and the superficial medial collateral ligament ; however, numerous incorrect diagnoses of tears to other ligaments were made. The most common error in diagnosing ligament injury was to mistake the increased external tibial rotation after ACL and medial collateral ligament sectioning as an indication of injury to the posterolateral ligament complex. 6. The diagnosis of the type of rotatory subluxation, when increases in tibial rotation occur after ligament injury, involves the difficulty of separating anterior-posterior subluxation of the medial tibial plateau from anterior-posterior
subluxation of the lateral tibial plateau. 7. Reliable joint arthrometer and/or stress radiography measurements should be developed as many variations of
clinicians’ diagnoses of joint motion limits and subluxations may invalidate conclusions of joint stability after surgery.
1983
Fukubayashi T, Torzilli PA, Sherman MF, et al: An in vitro biomechanical evaluation of anterior-posterior motion of the knee. Tibial displacement, rotation, and torque J Bone Joint Surg 64A. 258-264, 1982 8 Gollehon DL, Torzilli PA, Warren RF The role of the posterolateral and cruciate ligaments in the stability of the human knee A biomechanical study J Bone Joint Surg 69A. 233-242, 1987 9 Grood ES, Noyes FR Diagnosis and classification of knee ligament injuries: PartI Biomechanical precepts, in Feagin J Jr (ed). Crucial Ligament Injuries New York, Churchill Livingstone, 1987, pp 245-260 10 Grood ES, Noyes FR, Butler DL, et al. Ligamentous and capsular restraints preventing straight medial and lateral laxity in intact human cadaver knees . 1257-1269, 1981 J Bone Joint Surg 63A 11 Grood ES, Stowers SF, Noyes FR. Limits of movement in the human knee Effect of sectioning the posterior cruciate ligament and posterolateral structures J Bone Joint Surg 70A. 88-97, 1988 12 Grood ES, Suntay WJ A joint coordinate system for the clinical description of three-dimensional joint motion. Application to the knee J Biomech Eng 7
105 136-144,1983 13 Jakob RP, Staubli HU, Deland JT Grading the pivot shift Objective tests with implications for treatment. J Bone Joint Surg 69B. 294-299, 1987 14 Levy IM, Torzilli PA, Warren RF The effect of medial meniscectomy on anterior-posterior motion of the knee J Bone Joint Surg 64A 883-888, 1982 15. Markolf KL, Graff-Radford A, Amstutz HC In vivo knee stability. A quantitative assessment using an instrumented clinical testing apparatus J Bone Joint Surg 60A 664-674, 1978 16. Markolf KL, Mensch JS, Amstutz HC. Stiffness and laxity of the knee— the contributions of the supporting structures A quantitative in vitro study J Bone Joint Surg 58A 583-594, 1976 17. Mueller W The Knee—Form, Function, and Ligament Reconstruction Berlin, Springer-Verlag, 1982 18. Nielsen S, Kromann-Anderson C, Rasmussen O, et al: Instability of cadaver knees after transection of capsule and ligaments Acta Orthop Scand 55
30-34,1984 Noyes FR, Grood ES. Classification of ligament injuries. Why an anterolateral laxity or anteromedial laxity is not a diagnostic entity Instr Course Lect XXXVI. 185-200, 1987 20 Noyes FR, Grood ES Diagnosis and classification of knee ligament injuries: Part II. Clinical concepts in Feagin J. Jr (ed) Crucial Ligament Inluries. New York, Churchill Livingstone, 1987, pp 261-285 21. Noyes FR, Grood ES, Butler DL, et al. Clinical laxity tests and functional stability of the knee Biomechanical concepts. Clin Orthop 146 84-89, 19
1980 Grood ES, Suntay WJ, et al. The three-dimensional laxity of the anterior cruciate deficient knee as determined by clinical laxity tests lowa Orthop J 3. 32-44, 1983 23 Noyes FR, Grood ES, Torzilli PA Current concepts review. The definitions of terms for motion and position of the knee and injuries of the ligaments J Bone Joint Surg 71A. 465-472, 1989 24 Oliver JH, Coughlin LP Objective knee evaluation using the Genucom knee analysis system Clinical implications Am J Sports Med 15 571-578, 1987 25. Shino K, Inoue M, Honbe S, et al. Measurement of anterior instability of the knee. A new apparatus for clmical testing. J Bone Joint Surg 69B 22.
ACKNOWLEDGMENTS We are
grateful to the International Knee Documentation Committee for permitting and assisting us in conducting the experiments reported here. This work was supported in part by Grant AR-21172 from the National Institute of Arthritis, Musculoskeletal and Skin Diseases, and the Cincinnati
Noyes FR,
608-613,1987
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Comparison of (abstract) Orthop Trans
13 502, 1989 Grood ES, Hefzy MS, et al Error analysis of a system for measuring three dimensional joint motion J Biomech Eng 105 127-135, 1983 28 Torg JS, Conrad W, Kalen V. Clinical diagnosis of anterior cruciate ligament instablity in the athlete. Am J Sports Med 4. 84-93, 1976 27
Suntay WJ,
29 Torzilli PA, Greenberg RL, Insall J: An in vivo biomechanical evaluation of the anterior-posterior motion of the knee Roentgenographic measurement technique, stress machine, and stable population. J Bone Joint Surg 63A:
960-968,1981 30 Warren LF, Marshall JL The supporting structures and layers on the medial side of the knee. An anatomical analysis J Bone Joint Surg 61A.
56-62,1979
