Relationships Between Running Biomechanics and Femoral Articular Cartilage Thickness and Composition in Anterior Cruciate Ligament Reconstruction Patients.

BACKGROUND: Although individuals with anterior cruciate ligament reconstruction (ACLR) are at high risk for posttraumatic osteoarthritis, mechanisms underlying the relationship between running and knee cartilage health remain unclear. OBJECTIVE: We aimed to investigate how 30 min of running influences femoral cartilage thickness and composition and their relationships with running biomechanics in patients with ACLR and controls. METHODS: Twenty patients with ACLR (time post-ACLR: 14.6 ± 6.1 months) and 20 matched controls participated in the study. A running session required both groups to run for 30 min at a self-selected speed. Before and after running, we measured femoral cartilage thickness via ultrasound imaging. A MRI session consisted of T2 mapping. RESULTS: The ACLR group showed longer T2 relaxation times in the medial femoral condyle at resting compared with the control group (central: 51.2 ± 16.6 vs. 34.9 ± 13.2 ms, p = 0.006; posterior: 50.2 ± 10.1 vs. 39.8 ± 7.4 ms, p = 0.006). Following the run, the ACLR group showed greater deformation in the medial femoral cartilage than the control group (0.03 ± 0.01 vs. 0.01 ± 0.01 cm, p = 0.001). Additionally, the ACLR group showed significant negative correlations between resting T2 relaxation time in the medial femoral condyle and vertical impulse (standardized regression coefficients = -0.99 and p = 0.004) during running. CONCLUSIONS: Our findings suggest that those who are between 6 and 24 months post-ACLR have degraded cartilage composition and their cartilage deforms more due to running vGRF.

Effects of Chronic Pain on Static and Dynamic Postural Control in Chronic Ankle Instability.

OBJECTIVE: To identify the effects of chronic pain levels on static and dynamic postural (DP) control in individuals with chronic ankle instability (CAI). DESIGN: Cross-sectional study. SETTING: Controlled laboratory. PARTICIPANTS: Sixty participants were divided into the following 3 groups: 20 high pain individuals with CAI (high pain), 20 low pain individuals with CAI (low pain), and 20 healthy controls (control). INDEPENDENT VARIABLES: Groups (CAI with high pain, CAI with low pain, and control) and visual conditions (eyes open and closed) for single-leg stance. MAIN OUTCOME MEASURES: Participants performed single-leg stance with eyes open and closed, the star excursion balance test, and single-leg hop to stabilization. RESULTS: The high pain group experienced worse self-reported outcomes, including Foot and Ankle Ability Measure activities of daily living and sports, than the low pain and control groups. Regardless of visual condition, both the high and low pain groups exhibited decreased static postural control in mediolateral (ML) compared with the control group. Specifically, the high pain group showed decreased static postural control in ML under closed eyes compared with the low pain and the control groups. The high pain group showed less reach distance than the control group and increased DP control in vertical and overall DP stability index compared with the low and control groups. CONCLUSIONS: Chronic pain can significantly affect both static and DP control in individuals with CAI. Therefore, clinicians should consider chronic pain as one of the factors affecting postural control in individuals with CAI.

Postural control measured before and after simulated ankle inversion landings among individuals with chronic ankle instability, copers, and controls.

BACKGROUND: Postural control measured during single-leg stance and single-leg hop stabilization has been used to estimate sensorimotor function in CAI individuals and copers. To date, studies have not used postural control tasks as a way of measuring responses to sudden changes in sensory information after simulated ankle inversion landings. RESEARCH QUESTION: A cross-sectional study was performed to identify any differences in static and dynamic postural control before and after simulated ankle inversion landings among individuals with chronic ankle instability (CAI), copers, and healthy controls. METHODS: Nineteen CAI individuals, 19 copers, and 19 controls participated in this study. Participants performed 3 static and dynamic balance tasks before and after simulated ankle inversion landings onto a 25° tilted platform from a height of 30 cm. The main outcome measures were the center of pressure (COP) velocity and range from the single-leg stance, as well as the dynamic postural stability index from the single-leg hop stabilization. The Wilcoxon signed-rank test was used to compare posttest and pretest differences in static and dynamic postural control between groups. RESULTS: In the static postural control measures, the CAI group had a higher difference in COP velocity and COP range in the frontal plane (p < 0.05 and p < 0.05, respectively) than the coper group. In the dynamic postural control measures, the CAI group demonstrated a higher difference in the vertical stability index (p < 0.05) than the healthy control group. SIGNIFICANCE: CAI individuals have persistent worse postural control after somatosensory modulation due to their inability to adapt to sudden somatosensory modulation. Relative to CAI individuals, copers may have different abilities not only the integration of somatosensory input about ankle inversion modulation, but also the adaptation of the entire motor control system, preventing recurrent ankle sprains after an initial LAS. Therefore, somatosensory modulation may be the indicator of understanding CAI and coper.

The effects of kinesiophobia on postural control with chronic ankle instability.

BACKGROUND: Patients with chronic ankle instability (CAI) often experience injury-related fear following ankle injuries, a condition known as kinesiophobia. Little research has investigated the impact of kinesiophobia in patients with CAI. RESEARCH QUESTION: How does kinesiophobia impact the static and dynamic balance of individuals with CAI? METHODS: Fifty patients with CAI were divided into 2 subgroups based on their responses to the Tampa Scale of Kinesiophobia: 25 with kinesiophobia (CAI-K) and 25 without kinesiophobia (CAI-N). These groups were compared to 20 control participants. All participants performed a single-leg balance test with eyes open (EO) and eyes closed (EC). They also performed the Y-balance test (YBT) with EO. Romberg ratios were calculated as EC/EO and used for statistical analysis. RESULTS: No differences in static balance with EO and EC were found among three groups. However, the CAI-K group displayed a higher Romberg ratio in the mediolateral direction during static balance than both CAI-N and control groups. Additionally, both CAI-K and CAI-N groups displayed higher Romberg ratio in the anterior-posterior than controls. During YBT, the CAI-K group showed reduced reach distance in the anterior direction than CAI-N and control groups. SIGNIFICANCE: The CAI-K group relies more on visual feedback during static balance in the mediolateral direction than CAI-N and control groups. Furthermore, the CAI-K group displayed less anterior reach distance during YBT compared to the CAI-N and control groups. Clinicians should consider both psychological and physical factors when designing rehabilitation programs.