Background Chronic ankle instability (CAI) is associated with repetitive lateral ankle sprains, exhibiting postural-control deficits and altered gait biomechanics. Plantar cutaneous receptors have been theorized to affect postural control, but their contribution to postural-control deficits shown in CAI group during walking is unclear.
Objective To examine the effect of diminished plantar cutaneous sensation induced by cooling on gait kinematics in participants with or without CAI.
Design Case-control study.
Patients (or Participants) Seven individuals with CAI (age: 23.57±2.72 years; height: 166.14±7.74 cm; weight: 67.84±12.60 kg) and 10 healthy controls (age: 23.4±2.15 years; height: 164.29±5.88 cm; weight: 59.16±9.66 kg).
Interventions (or Assessment of Risk Factors) The plantar aspect of the participants' foot was submersed in ice water (0°C) for 10 minutes to induce hypoesthesia. Before and after the cooling procedure, plantar cutaneous sensation thresholds and walking trials were measured.
Main Outcome Measurements 3-dimensional lower extremity joint kinematics were recorded throughout the gait cycle. Group means and 95% confidence intervals were compared for percentages of the gait cycle where the confidence intervals did not overlap.
Results With plantar hypoesthesia, CAI participants indicated less hip adduction from 5% to 70% (mean difference=3.44±1.66°) and more knee internal rotation from 32% to 54%(mean difference=11.78±0.74°), and from 88% to 100%(mean difference=8.65±0.91°) of the gait cycle compared to healthy controls. No significant interactions were found between sensation and groups for lower extremity gait kinematics during walking.
Conclusions There was no significant effect of reduced plantar cutaneous sensation on gait kinematics in individual with or without CAI. The alterations in proximal joint kinematics can be a preservation strategy for individuals with CAI to complete normal ambulation. Our findings may explain that there are other factors contributing to altered proximal joint kinematics in CAI group during gait than plantar cutaneous sensation.