Vascular Function in Patients With Chronic Ankle Instability and Healthy Adults
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Abstract
CASEY BRUCE. Vascular function in patients with chronic ankle instability and healthy adults. (Under the direction of DR. ABBEY THOMAS FENWICK)Introduction: Patients with CAI display impaired sensorimotor output and deficits in afferent/sensory processing which negatively impact motor control and function. While these neural and sensorimotor deficits are well documented in patients with CAI, changes in the vascular structure and function are not commonly understood in this population. With many blood vessels running parallel and in close proximity to the nerves, it is likely that these structures are also damaged during joint injury such as a lateral ankle sprain. Vascular damage may impair blood flow to the nerves and muscles and may potentially be a source of poor sensorimotor function.Objective: To observe neurovascular function in the ankles of patients with and without chronic ankle instability to determine if vascular damage is present along with changes in neural excitability.Methods: A total of 10 participants with CAI and 7 healthy control participants participated in this study. Participants reported for a single testing session which contained spinal reflex excitability testing, blood flow analysis, and exercise. Blood flow analysis occurred before and immediately after exercise using the same procedures. Soleus spinal reflex excitability testing was assessed by eliciting a maximal H-reflex and M-response from the muscle. Blood flow was analyzed using an infrared thermal camera and captured videos of each participant’s lower legs and feet before, during, and after exercise. A region of interest (ROI) was selected posterior to the malleoli for both anterior and posterior views. The ROI was used for data analysis. Participants completed exercises containing three sets of ten of calf raises and bodyweight squats. Exercise were counterbalanced between subjects and separated by five minutes of rest. Hmax:Mmaxratios were compared between groups and limbs using 2x2 ANOVAs. Thermal imaging data were analyzed using Bland-Altman plots to determine agreement between the temperature of both limbs within each group. The association between peak temperature within each ROI and spinal reflex excitability were analyzed using Pearson Product Moment correlation coefficients were calculated for participants in the CAI group. Statistical analyses were performed using SPSS (IBM, Armonk, NY) and Matlab. Results: Spinal reflex excitability was not different between limbs or groups. There was no association between spinal reflex excitability and blood flow in the involved (posterior: r=-0.137, P=0.706; anterior: r=-0.338, P=0.339) or uninvolved (posterior: r=-0.039, P=0.916; anterior: r=-0.078, P=0.829) limbs of the CAI group. Analysis displays agreement in the surface temperatures obtained from both the posterior and anterior ROI between limbs in the participants with CAI. There was also agreement in posterior and anterior ROI surface temperatures between the limbs in health participants. Conclusions: Our findings reveal no statistical relationship between spinal reflex excitability and blood flow between limbs or groups when examining patients with CAI and healthy adults. Therefore, impaired neurovascular function may not contribute to the cycle of recurrent ankle sprains that is observed in patients with CAI.