The purpose of this study is to investigate the association between dynamic postural control and clinical measures of (ankle and hip strength, ankle DFROM and position sense) and radiological measures in patients with unilateral CAI.

Ankle sprains are among the most frequent injuries seen in emergency departments and in sports injury clinics. Among all ankle injuries, ankle sprains are the most common and account for approximately 80% of which 77% are lateral sprains. Ankle sprain incidence ranges from 5.3- 7.0 sprained ankles per one thousand persons per year in Europe and is estimated to be 23,000 ankle sprains occur per day in the United States. Up to 74% of individuals who sprained their ankle experience ongoing problems that prevent them from participating in sports and other physical activities. Lateral ankle sprain (LAS) typically occurs when the rear foot is supinated, and the leg is externally rotated. Inversion injuries affect the lateral ankle ligaments and subtalar ligaments concomitantly; around 73% of lateral ankle sprains are due to rupture or tear of the Anterior Talo-Fibular Ligament (ATFL), followed by Calcaneo Fibular Ligament (CFL) and cervical ligament of the subtalar joint with the interosseous talocalcaneal ligament respectively.

HYPOTHESES:

It will be hypothesized that:

1. There will be no relation between the radiological measures of the ankle joint and dynamic postural control in patients with unilateral CAI.
2. There will be no relation between hip muscles strength and dynamic postural control in patients with unilateral CAI.
3. There will be no relation between ankle performance (muscle strength, DFROM and position sense) and dynamic postural control in patients with unilateral CAI.
4. There will be a non-significant difference in the dynamic postural control between affected and normal lower limb.
5. There will be a non-significant difference in the radiological measures between affected and normal lower limb.
6. There will be a non-significant difference in the ankle performance between affected and normal lower limb.
7. There will be a non-significant difference in the muscle strength around the hip joint between the affected and normal lower limb.

Inclusion Criteria:

• Participants will be screened for eligibility and only those who meet the inclusion criteria according to Delahunt et al. (2010) and Gribble et al. (2013) will be enrolled in our study, i.e., they will participate if they have:

  1. At least one significant unilateral lateral ankle sprain in which the subject was unable to walk independently without the aid of crutches (the first sprain occurred more than 12 months ago).
  2. Repeated bouts of lateral ankle injury (last injury had to be more than three months prior to inclusion in the study).
  3. Feeling of ankle instability "giving way", at least 2 episodes in the last 6 months (Terada et al., 2014).
  4. Pain during intense loading.
  5. The Cumberland Ankle Instability Tool (CAIT) ≤ 24.
  6. Age range of 18-30 years (Delahunt et al., 2010).

Exclusion Criteria:

• *Patients will be excluded if they didn't meet the inclusion criteria mentioned above, such as:

  1. A previous trauma or surgery to the trunk or lower extremities other than an ankle sprain.
  2. Neurological or vestibular impairments with remaining deficits.
  3. No participant with CAI had acutely sprained his or her ankle in the 3 months prior to the testing.
  4. Participants will be excluded if they have participated in any rehabilitation in the past 6 months.
  5. Concussion or head injury or lower back pain in the past 6 months.

50 participants, with age between 18- 30 years, diagnosed with unilateral CAI will be recruited through direct referrals based on their availability to participate, thus, a sample of convenience will be used.