Objective measurements of static anterior and rotational knee laxity

Lateral Extra-articular Tenodesis Augmentation of Anterior Cruciate Ligament Reconstruction Is Most Commonly Indicated for Pivot Shift of Grade 2 or Greater and for Revision Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine the most common indications for lateral extra-articular tenodesis (LET) augmentation of anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic review of the literature was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched PubMed, Embase, Web of Science, and Cochrane Database of Systematic Reviews from 2000 to the present (June 2022). Studies that met the following criteria were included: patients of any age who underwent LET in addition to ACLR, studies reporting at least 1 indication for LET, and observational/randomized controlled trial study designs including prevalence of indications. Publications had to be reported in English and peer reviewed and to have originated in the United States or countries offering identical protocols and procedures.

RESULTS

A total of 463 studies were identified from the initial search, 23 of which met inclusion criteria and were included in the review. Eight of the 23 studies (34.8%) used a modified Lemaire technique, seven (30.4%) used a MacIntosh modified by Arnold-Coker, and eight (34.8%) used other techniques to perform LET. A total of 2,125 patients (53% female, 47% male [3 studies did not report sex]) underwent ACLR augmented with LET. The indications along with prevalence were as follows: positive pivot shift test (grade ≥2) (19 of 23, 82.6%), revision ACLR (12 of 23, 52.2%), ligamentous laxity (11 of 23, 47.8%), general sports participation (11 of 23, 47.8%), age less than 25 years (8 of 23, 34.8%), high risk of graft failure (5 of 23, 21.7%), and positive Lachman test (4 of 23, 17.4%).

CONCLUSIONS

Pivot shift grade ≥2 was the most common reason orthopaedic surgeons chose to add LET to ACLR, with revision ACLR, patient age <25, and general sports participation following closely behind.

LEVEL OF EVIDENCE

Level I to IV, systematic review of studies.

Comparing the Interobserver Reliability of 4 Methods Used to Measure Knee Laxity on Coronal Plane Stress Radiograph

Background

Varus and valgus knee stress radiographs provide valuable information in the pre- and postoperative evaluation of joint laxity in patients with multiligament knee injuries (MLKIs).

Purpose

To review the literature for described techniques of quantifying laxity on coronal stress radiographs of the knee and identify the most reliable method.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

A thorough literature search using the MEDLINE and Embase databases identified 4 studies with distinct methods for objectively measuring laxity on varus and valgus stress radiographs: Heesterbeek et al (2008), Jacobsen (1976), LaPrade et al (2004), and Sawant et al (2004). To compare these methods, 200 coronal plane stress radiographs from 50 patients with MLKIs were retrospectively reviewed from an MLKI database at a single institution. The amount of varus and valgus laxity on each radiograph was measured independently by 4 reviewers using each method. Intraclass correlation coefficients (ICCs) with 95% CIs were calculated to assess the interobserver reliability of each method overall and the varus and valgus measurements individually.

Results

For all 4 methods, the overall interobserver reliability was considered at least moderate. The method by Heesterbeek et al proved to have the highest interrater reliability in all domains-overall (ICC, 0.87 [95% CI, 0.85-0.90]), valgus (ICC, 0.83 [95% CI, 0.78-0.88]), and varus (ICC, 0.87 [95% CI, 0.83-0.90])-demonstrating good to excellent reliability both overall and in varus measurements and showing good reliability in valgus measurements. The method by Sawant et al demonstrated good reliability in valgus measurements. All other measures demonstrated moderate reliability.

Conclusion

Available methods for measuring knee joint laxity on varus and valgus knee stress radiographs in patients with MLKIs demonstrated moderate to good interobserver reliability. The method described by Heesterbeek et al proved to have the highest reliability overall as well as in measurements on varus and valgus views individually.

The validity of the Ligs digital arthrometer at different loads to evaluate complete ACL ruptures

Objective: The Ligs Digital Arthrometer is a recently launched versatile arthrometer that can be used for the quantitative assessment of knee and ankle joint laxity. This study aimed to evaluate the validity of the Ligs Digital Arthrometer for the diagnosis of complete anterior cruciate ligament (ACL) ruptures at different loads.

Materials and Methods: From March 2020 to February 2021, we included 114 normal subjects and 132 subjects diagnosed with complete ACL ruptures by magnetic resonance imaging (MRI) and eventually confirmed by arthroscopy in the study. Anterior knee laxity was independently measured by the same physical therapist using the Ligs Digital Arthrometer. Recorded anterior knee laxity and calculated the side-to-side difference (SSD) at 30, 60, 90, 120, and 150 N loads, respectively. The receiver operating characteristic (ROC) curve was used to determine the optimal laxity threshold, and the diagnostic value was evaluated by the area under the curve (AUC).

Results: The demographic data of the subjects were comparable between the two groups (p &gt; 0.05). The mean values of anterior knee laxity measured by the Ligs Digital Arthrometer between the complete ACL ruptures group and the control group were significantly different at 30, 60, 90, 120, and 150 N loads (p &lt; 0.001 for all). According to the results of ROC curve analysis, the optimal laxity threshold for the diagnosis of complete ACL ruptures was 1.1 mm SSD (Se = 66.7%, Sp = 69.3%) at 30 N, 1.3 mm (Se = 74.2%, Sp = 82.5%) at 60 N, 1.6 mm (Se = 79.5%, Sp = 94.7%) at 90 N, 1.9 mm (Se = 84.1%, Sp = 92.1%) at 120 N and 2.1 mm (Se = 85.6%, Sp = 91.2%) at 150 N. The AUC order at different loads from high to low was 150 N (0.948 [0.923–0.973])&gt;120 N (0.933 [0.903–0.963])&gt;90 N (0.902 [0.862–0.943])&gt;60 N (0.846 [0.799–0.893])&gt;30 N (0.720 [0.657–0.783]).

Conclusion: The Ligs Digital Arthrometer proved to be of high diagnostic value in complete ACL ruptures at 90 N, 120 N, and 150 N loads. The diagnostic value improved with the increase of load in a certain range. Based on the results of this study, as a portable, digital and versatile new arthrometer, the Ligs Digital Arthrometer was a valid and promising tool for diagnosing complete ACL ruptures.

Stress radiography at 30° of knee flexion is a reliable evaluation tool for high-grade rotatory laxity in complete ACL-injured knees

PURPOSE

To evaluate the diagnostic value of stress radiography and determine the cutoff values for high-grade anterolateral rotatory laxity in complete anterior cruciate ligament (ACL)-deficient knees at different positions.

METHODS

Forty-two patients with complete ACL rupture (group 1) and 37 normal subjects (group 2) were prospectively enrolled. The amount of anterior translation in the medial (MM) and lateral (LL) distance compartments and the difference between them (LL-MM distance) were measured using stress radiography at 30°, 45°, 60°, and 90° positions. The area under the receiver operating characteristic curve (AUC) was assessed for the presence of a high-grade (grade > 2) pivot shift.

RESULTS

The MM and LL distances in group 1 were significantly different at 30° and 45° positions (P < 0.05). The AUC of the MM (AUC, 0.903) and LL (AUC, 0.901) distances at the 30° position was significantly higher than that of the other positions (P = 0.000); however, the cutoff values were different to diagnose ACL injury (MM vs. LL, 3.1 mm vs. 5.4 mm). A 2.1-mm cutoff for the LL-MM distance showed 78.4% sensitivity and 90.3% specificity for detecting the presence of a high-grade pivot shift (AUC = 0.905, P = 0.000).

CONCLUSION

The cutoff values of stress radiography differed according to anatomical references and knee flexion positions. Stress radiography of a 2.1 mm difference in LL-MM distance at 30° of knee flexion can be a reliable method for high-grade rotatory laxity in complete ACL-injured knees.

LEVEL OF EVIDENCE

Level 1, diagnostic study.

A non-invasive biomechanical device to quantify knee rotational laxity: Verification of the device in human cadaveric specimens

Background

Biomechanical measurement tools have been developed and widely used to precisely quantify knee anterior-posterior laxity after anterior cruciate ligament (ACL) injury. However, validated objective device to document knee rotational laxity, though being developed by different researchers, are not yet widely used in the daily clinical practice. A new biomechanical device was developed to quantify knee internal and external rotations.

Methods

The reliability of the new biomechanical device which measures knee rotations were tested. Different torques (1-10Nm) were applied by the device to internally and externally rotate human cadaveric knees, which were held in a flexion angle of 30°. The rotations were measured by the device in degrees. There were two independent testers, and each tester carried out three trials. Intra-rater and inter-rater reliability were quantified in terms of intraclass correlation (ICC) coefficient among trials and between testers. The device was verified by the comparison with a computer assisted navigation system. ICC was measured. Mean, standard deviation and 95% confident interval of the difference as well as the root mean square difference were calculated. The correlations were deemed to be reliable if the ICC was above 0.75.

Results

The intra-rater and inter-rater reliability achieved high correlation for both internal and external rotation, ranged from 0.959 to 0.992. ICC between the proposed meter and the navigation system for both internal and external rotation was 0.78. The mean differences were 2.3° and 2.5° for internal and external rotation respectively.

Conclusions

A new knee rotational laxity meter was proposed in this study. Its reliability was verified by showing high correlation among trials. It also showed good correlation to a gold standard of measurement. It might be used to document knee rotational laxity for various purposes, especially after ACL injury, after further validation of the device in human subjects.

Comparison of a simplified skin pointer device compared with a skeletal marker for knee rotation laxity: A cadaveric study using a rotation-meter

AIM

To compare the measurements of knee rotation laxity by non-invasive skin pointer with a knee rotation jig in cadaveric knees against a skeletally mounted marker.

METHODS

Six pairs of cadaveric legs were mounted on a knee rotation jig. One Kirscher wire was driven into the tibial tubercle as a bone marker and a skin pointer was attached. Rotational forces of 3, 6 and 9 nm applied at 0°, 30°, 45°, 60° and 90° of knee flexion were analysed using the Pearson correlation coefficient and paired t-test.

RESULTS

Total rotation recorded with the skin pointer significantly correlated with the bone marker at 3 nm at 0° (skin pointer 23.9 ± 26.0° vs bone marker 16.3 ± 17.3°, r = 0.92; P = 0.0), 30° (41.7 ± 15.5° vs 33.1 ± 14.7°, r = 0.63; P = 0.037), 45° (49.0 ± 17.0° vs 40.3 ± 11.2°, r = 0.81; P = 0.002), 60° (45.7 ± 17.5° vs 34.7 ± 9.5°, r = 0.86; P = 0.001) and 90° (29.2 ± 10.9° vs 21.2 ± 6.8°, r = 0.69; P = 0.019) of knee flexion and 6 nm at 0° (51.1 ± 37.7° vs 38.6 ± 30.1°, r = 0.90; P = 0.0), 30° (64.6 ± 21.6° vs 54.3 ± 15.1°, r = 0.73; P = 0.011), 45° (67.7 ± 20.6° vs 55.5 ± 9.5°, r = 0.65; P = 0.029), 60° (62.9 ± 22.4° vs 45.8 ± 13.1°, r = 0.65; P = 0.031) and 90° (43.6 ± 17.6° vs 31.0 ± 6.3°, r = 0.62; P = 0.043) of knee flexion and at 9 nm at 0° (69.7 ± 40.0° vs 55.6 ± 30.6°, r = 0.86; P = 0.001) and 60° (74.5 ± 27.6° vs 57.1 ± 11.5°, r = 0.77; P = 0.006). No statistically significant correlation with 9 nm at 30° (79.2 ± 25.1° vs 66.9 ± 15.4°, r = 0.59; P = 0.055), 45° (80.7 ± 24.7° vs 65.5 ± 11.2°, r = 0.51; P = 0.11) and 90° (54.7 ± 21.1° vs 39.4 ± 8.2°, r = 0.55; P = 0.079). We recognize that 9 nm of torque may be not tolerated in vivo due to pain. Knee rotation was at its maximum at 45° of knee flexion and increased with increasing torque.

CONCLUSION

The skin pointer and knee rotation jig can be a reliable and simple means of quantifying knee rotational laxity with future clinical application.

Clinical course and recommendations for patients after anterior cruciate ligament injury and subsequent reconstruction: A narrative review

Almost all athletes who have suffered an anterior cruciate ligament (ACL) injury expect a full return to sports at the same pre-injury level after ACL reconstruction (ACLR). Detailed patient information on the reasonable outcomes of the surgery may be essential to improve patient satisfaction.

Pre-operative rehabilitation before ACLR should be considered as an addition to the standard of care to maximise functional outcomes after ACLR.

We propose an optimised criterion-based rehabilitation programme within a biopsychosocial framework.

No benchmark exists for evaluating return-to-sport (RTS) readiness after ACLR. Therefore, the authors propose a multi-factorial RTS test battery. A combination of both physical and psychological elements should be included in the RTS test battery.

There is need for shared decision-making regarding RTS.

Cite this article: EFORT Open Rev 2017;2:410-420. DOI: 10.1302/2058-5241.2.170011

Global rotation has high sensitivity in ACL lesions within stress MRI

PURPOSE

This study aims to objectively compare side-to-side differences of P-A laxity alone and coupled with rotatory laxity within magnetic resonance imaging, in patients with total anterior cruciate ligament (ACL) rupture.

METHODS

This prospective study enrolled sixty-one patients with signs and symptoms of unilateral total anterior cruciate ligament rupture, which were referred to magnetic resonance evaluation with simultaneous instrumented laxity measurements. Sixteen of those patients were randomly selected to also have the contralateral healthy knee laxity profile tested. Images were acquired for the medial and lateral tibial plateaus without pressure, with postero-anterior translation, and postero-anterior translation coupled with maximum internal and external rotation, respectively.

RESULTS

All parameters measured were significantly different between healthy and injured knees (P < 0.05), with exception of lateral plateau without stress. The difference between injured and healthy knees for medial and lateral tibial plateaus anterior displacement (P < 0.05) and rotation (P < 0.001) was statistically significant. It was found a significant correlation between the global rotation of the lateral tibial plateau (lateral plateau with internal + external rotation) with pivot-shift, and between the anterior global translation of both tibial plateaus (medial + lateral tibial plateau) with Lachman. The anterior global translation of both tibial plateaus was the most specific test with a cut-off point of 11.1 mm (93.8 %), and the global rotation of the lateral tibial plateau was the most sensitive test with a correspondent cut-off point of 15.1 mm (92.9 %).

CONCLUSION

Objective laxity quantification of ACL-injured knees showed increased sagittal laxity, and simultaneously in sagittal and transversal planes, when compared to their healthy contralateral knee. Moreover, when measuring instability from anterior cruciate ligament ruptures, the anterior global translation of both tibial plateaus and global rotation of the lateral tibial plateau add diagnostic specificity and sensitivity. This work strengthens the evidence that the anterior cruciate ligament plays an important biomechanical role in controlling the anterior translation, but also both internal and external rotation. The high sensitivity and specificity of this device in objectively identifying and measuring the multiplanar instability clearly guides stability restoration clinical procedures. Level of evidence Cross-sectional study, Level III.