The knee kinematic patterns and associated factors in healthy Thai adults

BACKGROUND

Reference values for normal knee kinematics were limited in Asian population and were influenced by race and other factors. This study was aimed to establish the reference values and identify the factors associated with knee kinematics in healthy Thai adults, aged 18-40 years.

METHODS

A retrospective cohort study was conducted between 2016 and 2020. Healthy Thai adults aged 18-40 years old with body mass index (BMI) between 18.5 and 24.9 kg/m2 were included. All eligible participants were attached with reflective markers. Their walking was captured by 8-digital cameras, and assessed by motion analysis software. The primary outcomes were average knee kinematic data (degrees) in three dimensional planes as valgus-varus, flexion-extension, and internal-external rotation. Paired t-test and multiple linear regression were applied to compare the outcomes and to determine their associated factors.

RESULTS

Ninety-eight participants (60 females and 38 males) were included with mean age 28.5 ± 5.4 years, and BMI 21.1 ± 2.0 kg/m2. Knee kinematics showed slight adduction during the swing phase, flexion during the stance phase, and obvious external rotation throughout the gait cycle, with a peak of 30-31 degrees during mid-swing. Right knee was significantly more adducted, flexed and externally rotated than the left side, particularly at mid-stance (P = 0.047, 0.017, and < 0.001, respectively). Females had more knee abduction, flexion and external rotation than males. Age, sex, and BMI were significantly correlated with knee abduction at terminal stance (correlation coefficient - 0.12, 95% confidence interval (CI) -0.23, -0.01; -1.37, 95%CI -2.54, -0.20; and - 0.32, 95%CI -0.61, -0.39, respectively), and rotation at mid-swing (correlation coefficient - 0.36, 95%CI -0.69, -0.02; -7.37, 95%CI -10.82, -3.92; and 0.89, 95%CI 0.01, 1.78, respectively).

CONCLUSION

Knee kinematics demonstrates external tibial rotation throughout the gait cycle, significant side differences, and are associated with age, sex, and BMI. Reference values from this study will be useful for functional gait assessment in healthy Thais. However, further comprehensive knee kinetic study including spatio-temporal parameter is recommended.

Does the contralateral healthy ankle of patient with ipsilateral mechanical lateral ankle laxity show greater lateral ankle laxity? Evaluation of the anterior talofibular ligament by stress ultrasonography

Background

A number of studies have evaluated risk factors for lateral ankle sprain (LAS) or chronic lateral ankle instability (CLAI). However, the definitive risk factors for LAS or CLAI remain controversial. The purpose of this study was to evaluate whether the contralateral healthy ankles of subjects with ipsilateral mechanical lateral ankle laxity (group I) show greater lateral ankle laxity in comparison to the healthy ankles of bilateral healthy controls (group B).

Methods

From March 2020, anterior talofibular ligament (ATFL) lengths of young adult volunteers were cross-sectionally measured in non-stress and stress positions using a previously reported stress ultrasonography (US) procedure. The ATFL ratio (the ratio of stress ATFL/non-stress ATFL length) was calculated as an indicator of lateral ankle laxity. The manual anterior drawer test (ADT) was also performed. The US findings of healthy ankles from groups I and B were compared.

Results

A total of 154 subjects in group B (mean age, 24.5 ± 2.8 years; male/female, 84/70) and 40 subjects in group I (mean age, 24.4 ± 2.3 years; male/female, 26/14) were included in the study. There was no significant difference in the ADT between the groups. There were no significant differences in the non-stress ATFL length (19.4 ± 1.8 vs. 19.3 ± 1.9, p = 0.84), stress ATFL length (20.8 ± 1.8 vs. 20.9 ± 1.9, p = 0.66), length change (1.5 ± 0.6 vs. 1.6 ± 0.6, p = 0.12) and ATFL ratio (1.08 ± 0.03 vs. 1.08 ± 0.03, p = 0.13) between the groups.

Conclusion

No significant difference was detected between the contralateral healthy ankles of subjects with ipsilateral mechanical lateral ankle laxity and those of bilateral healthy controls.

The contralateral knee is a good predictor for determining normal knee stability: a cadaveric study

PURPOSE

The goal is to evaluate contralateral knee joint laxity and ascertain whether or not contralateral symmetry is observable. Secondary, a validation of a knee laxity testing rig is provided.

METHODS

Seven pairs of cadaveric knee specimens have been tested under passive conditions with and without external loads, involving a varus/valgus and an external/internal rotational torque and an anteroposterior shear force.

RESULTS

Through the range of motion, the width of the varus/valgus laxity, internal/external laxity and anterior/posterior laxity for the medial and lateral compartment show no significant differences between left and right leg. These findings allow us to validate the setup, especially for relative values of laxity based on anatomical measures and knee joint biomechanics.

CONCLUSION

A multidirectional laxity symmetry has been demonstrated for the intact knee and its contralateral knee in passive conditions as in an anesthetized patient. The passive laxity evaluation setup has been validated. Our work furthermore demonstrated a pronounced difference in anteroposterior mobility between the medial and lateral compartment of the knee, with a more stable medial side and more mobile lateral side.

CLINICAL RELEVANCE

The contralateral knee can be used as reference for determining optimal knee laxity peri-operatively in total knee replacement and ligament reconstruction.

LEVEL OF EVIDENCE

Level IV, Case series.