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Title: Using an Arthrometer to Quantify Ankle Laxity: An Infographic Summary

Lateral ankle sprains are a common musculoskeletal injury. The anterior talofibular ligament (ATFL) is the primary ligament involved and is assessed via an anterior drawer test. Clinically assessing joint laxity has been a subjective task. Evaluating both magnitude of translation and quality of the endfeel has presented challenges. Until recently, a reliable and valid arthrometer to test joints other than the knee has not been available. The Mobil-Aider arthrometer has undergone bench testing for validity, reliability testing in healthy persons, and most recently the testing of participants for pathology. A summary of these studies is available in the Online Supplement . The goal of this study was to determine the ability of the arthrometer to objectively identify the anterior translation of the ankle and the relationship to the clinical diagnosis. The participant was evaluated by a physician and magnitude of ankle sprain was determined. An arthrometer was used to perform an anterior drawer test (uninjured before injured, 3 measures each) in the prone position. Both clinicians were blinded to the data of the other. There were 30 participants, 10 per group (uninjured, 1° sprain, 2° sprain). Mann-Whitney U testing found significant differences between the control and grade 1 ankle sprain groups ( P < .001), the control and grade 2 ankle sprain groups ( P < .001), and the grade 1 and grade 2 ankle sprain groups ( P = .004). There was ± 0.31 mm difference in anterior translation between healthy ankles, whereas there was 1.11 mm and 2.16 mm difference between ankles in grade 1 and grade 2 sprains, respectively. The anterior drawer test is the gold standard for clinical ATFL testing, but the subjective nature of this test poses challenges. Technology is available to assess ankle joint laxity and enhance the objectivity of patient assessment and throughout the recovery process. An arthrometer is a valuable tool in quantifying orthopaedic examination.

 
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NSF-PAR ID:
10392841
Author(s) / Creator(s):
 
Publisher / Repository:
SAGE Publications
Date Published:
Journal Name:
Sports Health: A Multidisciplinary Approach
Volume:
16
Issue:
1
ISSN:
1941-7381
Format(s):
Medium: X Size: p. 26-28
Size(s):
["p. 26-28"]
Sponsoring Org:
National Science Foundation
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  1. Background

    Lateral ankle sprains are a common musculoskeletal injury across a variety of activities. Researchers have sought to identify a method to objectively assess joint laxity with a device that is simple to use and affordable.

    Aim

    The purpose of this study was to assess the use of an ankle arthrometer on individuals with ankle sprains.

    Methods

    The participant was evaluated by the physician and the degree of ankle sprain was identified. In the prone position, the arthrometer was used to perform an anterior drawer test (uninjured before injured, 3 measures each). Both clinicians were blinded to the data of the other.

    Results

    There were 30 participants, 10 in each group (uninjured, grade 1 sprain, grade 2 sprain). Mann-Whitney U testing found significant differences between the control and grade I ankle sprain groups (P < .001), the control and grade II ankle sprain groups (P < .001), and the grade I and grade II ankle sprain groups (P = .004). There was ±0.31-mm difference in anterior translation between healthy ankles, whereas there was 1.11- and 2.16-mm difference between ankles in grade 1 and grade 2 sprains, respectively.

    Clinical Application

    Despite the manual anterior drawer test being convenient, the subjectivity makes it unreliable. This study is consistent with prior literature about the difference in translation (millimeters) between the uninjured and injured ankles corresponding to the magnitude of ankle laxity. This study also contributes to the evolving evidence to support the relationship of a ratio of measures (injured/uninjured) as an objective measure of laxity. These comparisons to the individual’s healthy ankle mitigate the variability of the normative values. The use of an arthrometer to assess ankle joint laxity enhances the objectivity of patient assessment throughout the recovery process.

    Levels of Evidence:

    Level III

     
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  2. INTRODUCTION: In practice, the use of a whip stitch versus a locking stitch in anterior cruciate ligament (ACL) graft preparation is based on surgeon preference. Those who prefer efficiency and shorter stitch time typically choose a whip stitch, while those who require improved biomechanical properties select a locking stitch, the gold standard of which is the Krackow method. The purpose of this study was to evaluate a novel suture needle design that can be used to perform two commonly used stitch methods, a whip stitch, and a locking stitch, by comparing the speed of graft preparation and biomechanical properties. It was hypothesized that adding a locking mechanism to the whip stitch would improve biomechanical performance but would also require more time to complete due to additional steps required for the locking technique. METHODS: Graft preparation was performed by four orthopaedic surgeons of different training levels where User 1 and User 2 were both attendings and User’s 3 and 4 were both fellows. A total of 24 matched pair cadaveric knees were dissected and a total of 48 semitendinosus tendons were harvested. All grafts were standardized to the same size. Tendons were randomly divided into 4 groups (12 tendons per group) such that each User performed analogous stitch on matched pair: Group 1, User 1 and User 3 performed whip stitches; Group 2, User 1 and User 3 performed locking stitches; Group 3, User 2 and User 4 performed whip stitches; Group 4, User 2 and User 4 performed locking stitches. For instrumentation, the two ends of tendon grafts were clamped to a preparation stand. A skin marker was used to mark five evenly spaced points, 0.5 cm apart, as a guide to create a 5-stitch series. 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  4. Background:

    Graft placement is a modifiable and often discussed surgical factor in anterior cruciate ligament (ACL) reconstruction (ACLR). However, the sensitivity of functional knee mechanics to variability in graft placement is not well understood.

    Purpose:

    To (1) investigate the relationship of ACL graft tunnel location and graft angle with tibiofemoral kinematics in patients with ACLR, (2) compare experimentally measured relationships with those observed with a computational model to assess the predictive capabilities of the model, and (3) use the computational model to determine the effect of varying ACL graft tunnel placement on tibiofemoral joint mechanics during walking.

    Study Design:

    Controlled laboratory study.

    Methods:

    Eighteen participants who had undergone ACLR were tested. Bilateral ACL footprint location and graft angle were assessed using magnetic resonance imaging (MRI). Bilateral knee laxity was assessed at the completion of rehabilitation. Dynamic MRI was used to measure tibiofemoral kinematics and cartilage contact during active knee flexion-extension. Additionally, a total of 500 virtual ACLR models were created from a nominal computational knee model by varying ACL footprint locations, graft stiffness, and initial tension. Laxity tests, active knee extension, and walking were simulated with each virtual ACLR model. Linear regressions were performed between internal knee mechanics and ACL graft tunnel locations and angles for the patients with ACLR and the virtual ACLR models.

    Results:

    Static and dynamic MRI revealed that a more vertical graft in the sagittal plane was significantly related ( P < .05) to a greater laxity compliance index ( R2= 0.40) and greater anterior tibial translation and internal tibial rotation during active knee extension ( R2= 0.22 and 0.23, respectively). Similarly, knee extension simulations with the virtual ACLR models revealed that a more vertical graft led to greater laxity compliance index, anterior translation, and internal rotation ( R2= 0.56, 0.26, and 0.13). These effects extended to simulations of walking, with a more vertical ACL graft inducing greater anterior tibial translation, ACL loading, and posterior migration of contact on the tibial plateaus.

    Conclusion:

    This study provides clinical evidence from patients who underwent ACLR and from complementary modeling that functional postoperative knee mechanics are sensitive to graft tunnel locations and graft angle. Of the factors studied, the sagittal angle of the ACL was particularly influential on knee mechanics.

    Clinical Relevance:

    Early-onset osteoarthritis from altered cartilage loading after ACLR is common. This study shows that postoperative cartilage loading is sensitive to graft angle. Therefore, variability in graft tunnel placement resulting in small deviations from the anatomic ACL angle might contribute to the elevated risk of osteoarthritis after ACLR.

     
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  5. ABSTRACT

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