Is the KiRA Device Useful in Quantifying the Pivot Shift in Anterior Cruciate Ligament-Deficient Knees?

Comprehensive Clinical Examination of ACL Injuries

A comprehensive clinical examination of the potentially anterior cruciate ligament (ACL)-deficient knee should proceed as follows: inspection; palpation; range of motion; varus and valgus stress; neurovascular status; and finally provocative maneuvers. The Lachman, anterior drawer, Lever, and pivot shift tests are all greater than 90% specific for ACL pathology. Due to the relatively high coincidence of ACL injuries and those to the posterior cruciate ligament, posterolateral corner , posteromedial corner , and menisci, it is critical that the examiner perform provocative maneuvers to evaluate the integrity of these structures as well.

Mobile App for Enhanced Anterior Cruciate Ligament (ACL) Assessment in Conscious Subjects: "Pivot-Shift Meter"

Anterior cruciate ligament (ACL) instability poses a considerable challenge in traumatology and orthopedic medicine, demanding precise diagnostics for optimal treatment. The pivot-shift test, a pivotal assessment tool, relies on subjective interpretation, emphasizing the need for supplementary imaging. This study addresses this limitation by introducing a machine learning classification algorithm integrated into a mobile application, leveraging smartphones' built-in inertial sensors for dynamic rotational stability assessment during knee examinations. Orthopedic specialists conducted knee evaluations on a cohort of 52 subjects, yielding valuable insights. Quantitative analyses, employing the Intraclass Correlation Coefficient (ICC), demonstrated robust agreement in both intraobserver and interobserver assessments. Specifically, ICC values of 0.94 reflected strong concordance in the timing between maneuvers, while signal amplitude exhibited consistency, with the ICC ranging from 0.71 to 0.66. The introduced machine learning algorithms proved effective, accurately classifying 90% of cases exhibiting joint hypermobility. These quantifiable results underscore the algorithm's reliability in assessing knee stability. This study emphasizes the practicality and effectiveness of implementing machine learning algorithms within a mobile application, showcasing its potential as a valuable tool for categorizing signals captured by smartphone inertial sensors during the pivot-shift test.

Medial meniscal lesions increase antero-posterior laxity in knees with anterior cruciate ligament injury

PURPOSE

The aim of this study was to quantify the impact of concomitant meniscal lesions on knee laxity using a triaxial accelerometer in a large population of patients affected by anterior cruciate ligament (ACL) injury.

METHODS

A total of 326 consecutive patients (261 men and 65 women, mean age 31.3 ± 11.3) undergoing primary ACL reconstruction, were preoperatively evaluated through Lachman and pivot shift tests using a triaxial accelerometer to quantify knee laxity. An analysis based on the presence of meniscal tears assessed during surgery was performed to evaluate the impact of meniscal lesions on knee laxity.

RESULTS

The anterior tibial translation (Lachman test) presented significantly higher values in patients with medial meniscal lesions (7.3 ± 1.7 mm, p = 0.049) and both medial and lateral meniscal lesions (7.7 ± 1.6 mm, p = 0.001) compared to patients without concomitant meniscal lesions (6.7 ± 1.3 mm). Moreover, patients with both medial and lateral meniscal lesions presented significantly higher values of anterior tibial translation compared to patients with lateral meniscal lesions (p = 0.049). No statistically significant differences were found between the groups in terms of tibial acceleration (pivot shift test).

CONCLUSION

This study demonstrated that the contribution of concomitant meniscal lesions to knee laxity can be objectively quantified using a triaxial accelerometer in ACL-injured knees. In particular, medial meniscus lesions, alone or in association with lateral meniscus lesions, determine a significant increase of the anterior tibial translation compared to knees without meniscus tears.

LEVEL OF EVIDENCE

Level IV.

Multiclass Support Vector Machine improves the Pivot-shift grading from Gerdy's acceleration resultant prior to the acute Anterior Cruciate Ligament surgery

INTRODUCTION

Rotatory laxity acceleration still lacks objective classification due to interval grading superposition, resulting in a biased pivot shift grading prior to the Anterior Cruciate Ligament (ACL) reconstruction. However, data analysis might help improve data grading in the operative room. Therefore, we described the improvement of the pivot-shift categorization in Gerdy's acceleration under anesthesia prior to ACL surgery using a support vector machine (SVM) classification, surgeon, and literature reference.

METHODS

Seventy-five patients (aged 30.3 ± 10.2 years, and IKDC 52.0 ± 16.5 points) with acute ACL rupture under anesthesia prior to ACL surgery were analyzed. Patients were graded with pivot-shift sign glide (+), clunk (++), and (+++) gross by senior orthopedic surgeons. At the same time, the tri-axial tibial plateau acceleration was measured. Categorical data were statistically described, and the accelerometry and categorical data were associated (α = 5%). A multiclass SVM kernel with the best accuracy trained by orthopedic surgeons and assisted from literature for missing data was compared with experienced surgeons and literature interval grading. The cubic SVM classifier achieved the best grading.

RESULTS

The intra-group proportions were different for each grading in the three compared strategies (p < 0.001). The inter-group proportions were different for all comparisons (p < 0.001). There were significant (p < 0.001) associations (Tau: 0.69, -0.28, and -0.50) between the surgeon and SVM, the surgeon and interval grading, and the interval and SVM, respectively.

CONCLUSION

The multiclass SVM classifier improves the acceleration categorization of the (+), (++), and (+++) pivot shift sign prior to the ACL surgery in agreement with surgeon criteria.

Anatomical and Biomechanical Characteristics of the Anterolateral Ligament: A Descriptive Korean Cadaveric Study Using a Triaxial Accelerometer

Background and Objectives: The anterolateral ligament (ALL) could be the potential anatomical structure responsible for rotational instability after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate the anatomical and biomechanical characteristics of the ALL in Korean cadaveric knee joints. Materials and Methods: Twenty fresh-frozen cadaveric knees were dissected and tested. Femoral and tibial footprints of the ALL were recorded. Pivot shift and Lachman tests were measured with KiRA. Results: The prevalence of ALL was 100%. The average distance of the tibial footprint to the tip of the fibular head was 19.85 ± 3.41 mm; from the tibial footprint to Gerdy's tubercle (GT) was 18.3 ± 4.19 mm; from the femoral footprint to the lateral femoral epicondyle was 10.25 ± 2.97 mm. ALL's footprint distance was the longest at 30° of flexion (47.83 ± 8.05 mm, p < 0.01) in a knee with intact ALL-ACL and neutral rotation. During internal rotation, the footprint distance was the longest at 30° of flexion (50.05 ± 8.88 mm, p < 0.01). Internal rotation produced a significant increase at all three angles after ACL-ALL were transected (p = 0.022), where the footprint distance was the longest at 30° of flexion (52.05 ± 7.60 mm). No significant difference was observed in KiRA measurements between intact ALL-ACL and ALL-transected knees for pivot shift and Lachman tests. However, ACL-ALL-transected knees showed significant differences compared to the intact ALL-ACL and ALL-transected knees (p < 0.01). Conclusions: The ALL was identified as a distinct ligament structure with a 100% prevalence in this cadaveric study. The ALL plays a protective role in internal rotational stability. An isolated ALL transection did not significantly affect the ALL footprint distances or functional stability tests. Therefore, the ALL is thought to act as a secondary supportive stabilizer for rotational stability of the knee joint in conjunction with the ACL.

Pivot shift intraoperative quantitative assessment using a smartphone accelerometer in ACL deficient knees

PURPOSE

The Pivot Shift (PS) test is a complex clinical sign that assesses the internal rotation and anterior tibial translation, which occurs abnormally in ACL deficient-knees. Because of the high inter-observer variability, different devices have been designed to characterize this complex movement in quantitative variables. The objective of this pilot study is to validate the reproducibility of intraoperative quantitative assessment of the PS with a smartphone accelerometer.

METHODS

Twelve ACL-injured knees were included and compared with the contralateral uninjured side. The PS was measured by two independent observers utilizing a smartphone accelerometer and graded according to the IKDC classification. Measurements were taken preoperatively, intraoperatively and postoperatively. Intraoperative readings were taken during each stage of reconstruction or repair of meniscoligamentous lesions including meniscal lesions, ramp lesions, ACL reconstruction and lateral tenodesis. Reproducibility of the measurements were evaluated according to an intraclass correlation coefficient (ICC).

RESULTS

The intra-observer reliability was good for the first examiner and excellent for the second examiner, with the ICC 0.89 [0.67, 0.98] p < 0,001 and ICC 0.97 [0.91, 1.0] p < 0,001 respectively. The inter-observer reliability was excellent between the two observers with the ICC 0.99 [0.97, 1.0] p < 0,001. The mean tibial acceleration measured 3.45 m.s² (SD = 1.71) preoperatively on the injured knees and 1.03 m.s² (SD = 0.36) on the healthy knees, demonstrating a significant difference following univariate analysis p < 0.001. Postoperatively, no significant difference was observed between healthy and reconstructed knees The magnitudes of tibial acceleration values were correlated with the PS IKDC grade.

CONCLUSION

The smartphone accelerometer is a reproducible device to quantitatively assess the internal rotation and anterior tibial translation during ACL reconstruction surgery. The measurements are influenced by the different surgical steps. Other larger cohort studies are needed to evaluate the specific impact of each step of the ACL reconstruction and meniscal repair on this measurement. An external validation using other technologies are needed to validate the reliability of this device to assess the PS test.

LEVEL OF EVIDENCE

Level IV, case series, pilot study.

Is the Rotatory Knee Stability Immediately Decreased Following a Competitive Soccer Match?

Fatigue induced by soccer playing increases physical efforts, which might alter the transverse knee stability, a known factor that promotes knee injuries, particularly anterior cruciate ligament injury. Thereby, primarily, we aimed to determine whether rotatory knee stability decreases immediately following a competitive soccer match in amateur players. Furthermore, we assessed the role of the preferred and non-preferred limbs to kick a ball in rotatory knee stability and the correlation between performance parameters and rotatory knee stability. We hypothesized that the knee stability decreases immediately after a competitive soccer match in amateur players. Eight healthy amateur soccer players (aged 27.2 ± 4.7 years and with body mass index of 23.8 ± 1.2 kg m−2) were included immediately before and after a competitive soccer match. The rotatory knee stability was assessed in the preferred and non-preferred limbs through the acceleration and jerk of the pivot shift maneuver and by the internal knee rotation of a pivoting landing task. Two-way repeated-measures ANOVA for factors time (before and after the soccer match) and limb (preferred and non-preferred) and multiple comparisons were performed using α = 5%. There was a statistical significance for the main factor time in the acceleration (5.04 vs. 6.90 ms−2, Δ = 1.86 ms−2, p = 0.020, η2 = 0.331) and jerk (18.46 vs. 32.10 ms−2, Δ = 13.64 ms−2, p = 0.004, η2 = 0.456) of the pivot shift maneuver. Rotatory stability decreases following a competitive soccer match in amateur soccer players under fatigue. Both the acceleration and jerk during the pivot shift maneuver is increased without significant internal knee rotation changes during the pivoting landing task.