The Effect of Additional Neurodynamic Intervention in Patients With Chronic Ankle Instability

Approximately 40% of acute ankle sprain would develop into chronic ankle instability (CAI). Chronic ankle instability is characterized by pain, repeated sprains and giving way. Recently, the pathomechanical impairment, sensory-perceptual impairment and motor-behavioral impairment have been documented in the chronic ankle instability model. Previous research revealed that compared to the control subjects, people with CAI had lower pressure pain threshold (PPT). This increased mechanosensitivity of the neural tissues around the ankle might account for pain and dysfunction in people with CAI. Also, the other study indicated that in subjects following ankle inversion sprain there is greater restriction of knee extension on the injured side compared to non-injured side in the slump test with the ankle plantar flexion and inversion, which may suggest the restriction in mobility of the common peroneal tract. However, the effects of neurodynamic intervention, which addresses the mechanosensitivity problems, in people with CAI are still unclear.

Therefore, the aim of the study is to investigate the effect of additional neurodynamic intervention on the ankle range of motion, mechanosensitivity, balance performance and self-reported function.

Approximately 40% of acute ankle sprain would develop into chronic ankle instability (CAI). Chronic ankle instability is characterized by pain, repeated sprains and giving way. Recently, the pathomechanical impairment, sensory-perceptual impairment and motor-behavioral impairment have been documented in the chronic ankle instability model. Previous research revealed that compared to the control subjects, people with CAI had lower pressure pain threshold (PPT). This increased mechanosensitivity of the neural tissues around the ankle might account for pain and dysfunction in people with CAI. Also, the other study indicated that in subjects following ankle inversion sprain there is greater restriction of knee extension on the injured side compared to non-injured side in the slump test with the ankle plantar flexion and inversion, which may suggest the restriction in mobility of the common peroneal tract. However, the effects of neurodynamic intervention, which addresses the mechanosensitivity problems, in people with CAI are still unclear.

Therefore, the aim of the study is to investigate the effect of additional neurodynamic intervention on the ankle range of motion, mechanosensitivity, balance performance and self-reported function.

The investigators will recruit 40 patients with chronic ankle instability and compare the effect of two intervention groups (balance training alone, combined balance training and neurodynamic intervention for the common peroneal nerve) on ankle range of motion (ROM), active knee ROM, pressure pain threshold , Y balance test and Foot and ankle ability measure (FAAM).

Independent test and Chi-square test are used to examine demographic data of the groups differences.

Two-way repeated measures ANOVA is used to examine the intervention effect with the alpha level set at 0.05

Eligibility Criteria:
Inclusion Criteria:

1. History of at least two ankle sprains in the same leg, of which the first sprain is more than one year
2. Leading to at least one interrupted day of desired physical activity
3. The Cumberland Ankle Instability Tool (CAIT) ≦ 24
4. Slump test in ankle plantar flexion with inversion: positive

Exclusion Criteria:

1. Pregnancy
2. Surgical treatments
3. Previous fractures in either lower extremity
4. Any concomitant lower extremity pathology, for example, vascular disease, osteoarthritis and rheumatoid arthritis
5. Significant pain or injury to the lumbar or cervical spine
6. Regular use of medication: anti-inflammatory drugs, painkiller, steroid or muscle relaxants
7. Previous manual therapy or exercise interventions received on the lower extremity within the previous 3 months