Management of Chronic Ankle Instability

Original Editor - Ewa Jaraczewska based on the course by Helene Simpson
Top Contributors - Ewa Jaraczewska, Jess Bell, Kim Jackson and Matt Huey

Definition of Chronic Ankle Instability (CAI)

Chronic ankle instability (CAI) has been defined as “repetitive bouts of lateral ankle instability resulting in numerous ankle sprains.” Chronic instability refers to a feeling of apprehension in the ankle, “giving way” and recurrent ankle sprains, persisting for a minimum of six months after the initial sprain. Symptoms include:

• Lateral ankle pain
• Chronic swelling
• Difficulty walking on uneven terrain

Based on the International Classification of Function, Health and Disability (ICF) model, the effects of CAI on function and health include:

• In terms of impairments:
  • Increased ligamentous laxity
  • Proprioceptive deficits

• In terms of activity limitations:
  • Inability to walk
  • Inability to jump

• In terms of participation:
  • Cessation of sport
  • Withdrawing from or decreasing occupational involvement
  • Decreasing levels of exercise
  • Change in the type of sport

Long-term Outcomes

Patients with CAI experience a reduction in their physical quality of life. Treatments may improve stability, but they take a long time and may require specialised equipment. Konradsen et al. conducted a study that followed-up with patients seven years post-ankle inversion trauma. They found the following:

• 32% of patients reported chronic complaints of pain, swelling or recurrent sprains
• 72% of the subjects with residual disability reported that they were functionally impaired by their ankle
• 4% of patients experienced pain at rest and were severely disabled
• 19% were bothered by repeated inversion injuries
• 43% of these subjects felt that they could compensate by using an external ankle support
• 85% of people who develop CAI after unilateral sprain reported problems in the contralateral ankle

According to Hertel, one sprain guarantees another. And Struijs and Kerkhoffs found that there was a 30% recurrence of sprains within a year of injury.

Additional reported long-term outcomes include:

• Articular cartilage defects on the medial side of the joint due to:
  • Tearing of anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL)
  • Altering and increasing peak cartilage strain
  • Leading to  tibiotalar cartilage degeneration (OA)

• Anterior talar positional fault
• Altered movement patterns in unstable ankles:
  • Landing in more dorsiflexion in an attempt to minimise reliance on lateral ligaments and increase bony stability
  • In drop jump: greater maximum calcaneal eversion and frontal displacement of the body
  • Faster time to peak ground reaction force in drop landing
  • Greater medial ground reaction force
  • Metatarsal height is lowered during the terminal swing of gait

Mechanical and Functional Instability

There are two commonly accepted subgroups of CAI: mechanical instability and functional instability. In Hertel's model of ankle stability, mechanical and functional instability are part of a continuum. Recurrent sprains occur when both conditions are present.

Mechanical Instability

Mechanical instability is referred to as pathological ligamentous laxity about the ankle-joint complex. Mechanical instability may be caused by various anatomic changes that are present in isolation or in combination. They can lead to pathologies that are responsible for ankle instability.

Functional Instability

There is no universally approved definition of functional ankle instability. Based on the definition established by Evans et al., functional instability is a subjective complaint of weakness. Lentell et al. describe functional instability as ankle pain and the perception that the injured ankle is less functional than the other ankle or less functional than pre-injury. Tropp et al. concluded that functional instability could be defined as a joint motion that does not exceed normal physiologic limits but is no longer controlled voluntarily.

Impaired proprioceptive and neuromuscular control can be responsible for functional instability.

Mechanical instability is typically presented as excessive inversion, laxity of the rear foot, and excessive anterior laxity of the talocrural joint. It can be caused by ligament instability or degenerative and chronic inflammatory process. In functional instability, on the other hand, patients complain about the sense of the ankle giving way. The delayed neuromuscular response, proprioceptive deficits or impaired balance can cause this symptom.

Table 1 summarises the causes and results of mechanical and functional ankle instability:

Diagnostic Procedures

Diagnostic procedures can help clinicians confirm the presence of various ankle deficiencies, including reduced range of motion and perceived disability. This can help to define/diagnose a specific condition. Clinicians should consider if research findings suggest "consistent positive utility" before deciding which diagnostic tool to use:

• Anterior drawer test: performed in slight knee flexion to relax the gastrocnemius. However, Kovaleski et al. suggest testing with the knee flexed to 90° and the ankle at 10° of plantar flexion to isolate the anterior talofibular ligament. A bilateral comparison is recommended. Excessive anterior translation and a lack of a solid end feel indicate a positive test result.
• Stress radiography: used to quantify the extent of ankle-joint laxity. It shows the separation of the bony joint structures while a force is applied. Clinically, it helps to identify excessive strain within the ligamentous structures. A total anterior translation greater than 9 mm or translation greater than 5 mm (or both) when compared with the contralateral side indicates significant laxity of the anterior talofibular ligament. Pathologic laxity of the calcaneofibular ligament is demonstrated by a talar tilt angle greater than 10°, or an angle that is more than 5° greater than the contralateral limb.
• MRI: not considered conclusive. Negative MRI results must be viewed with caution in a symptomatic patient and arthroscopy should be considered.
• Diagnostic ultrasound: evidence suggests that diagnostic ultrasound offers a moderate to strong confirmation of lateral ligamentous injury. It shows increased lateral ligament length during the anterior drawer and talar tilt tests in individuals with a history of CAI.
• Stable force plates: suggested for gait and hop stability assessment:

• Imaged guided injections of cortisone as a clinical diagnostic tool. The Delphi-based consensus of experts from the European Society of Musculoskeletal Radiology found that intraarticular foot and ankle anaesthetic injections performed under imaging guidance provide precise information about the source of pain.

Physiotherapy Management

Conservative management is the treatment of choice for acute lateral ankle injuries - a surgical approach for these injuries is reserved for special cases. Currently available conservative modalities include:

• Neuromuscular training
• Balance training
• Mobilisation
• Neuromuscular control by peronei (theraband and isokinetic training do not affect ankle evertor strength)
• Braces and taping
• Flexibility and strength training

Neuromuscular Training

• De Vries et al. found that neuromuscular training alone has a positive short-term outcome and patients had better function. This type of training is a key feature of the majority of conservative treatment regimes.
• A study by Kim et al. found that athletes with unstable ankles have an altered gait pattern - i.e. a relatively inverted ankle position during the initial contact and midstance. Engaging in six weeks of neuromuscular training immediately changed the athlete's ankle orientation to a relatively more inverted direction during jump landing. However, there was no effect on walking and running.
• According to Guzmán-Muñoz et al., four weeks of neuromuscular training improved postural control in college volleyball players with functional ankle instability (FAI) .
  

  Step 1

Step 2

Step 3

Guide to Neuromuscular Training

Neuromuscular training is an "unconscious activation of dynamic restraints in preparation and in response to joint motion and loads to maintain and restore functional joint stability".

Goals of neuromuscular training:

1. To optimise lower limb postural control
2. To restore active stability by training

Exercises

Exercises are performed in closed chain and functional positions:

• Single limb stance on wobble board or balance mat
• Single limb ball toss
• Single leg theraband kicks and step downs (see Figures with Steps 1-3)

Balance Training

• While investigating functional ankle instability and health-related quality of life, Arnold et al. concluded that balance training can affect multiple joints and produce overall improvements.
• McKeon et al. showed that balance training significantly improves static postural control and dynamic postural control.

• A prospective cohort study by Sefton et al. found that rehabilitation affects sensorimotor system function.
• Based on a review of randomised controlled trials, Mollà Casanova et al. concluded that balance training significantly improves functionality, instability, and dynamic balance outcomes in people with chronic ankle instability.

Guide to Balance Training

The literature indicates that the following balance measures should guide clinical practice. However, De Vries et al. did not find a correlation with function:

• Centre-of-pressure (COP) excursion

• Time-to-boundary (TTB) after landing
• Peak plantar analysis
• Star Excursion Balance Test (SEBT)

Proprioception

Kinesthesia and joint position sense (JPS) are usually impaired in patients with chronic ankle instability. The testing methodology for proprioception includes:

• Kinesthesia: assessed using threshold-to-detection of passive motion
• Joint position sense: assessed using active and passive joint placing reproduction

Therapeutic Interventions

• Multi-station exercise regime once per week
  • Ankle disc training, balance pad

• Perturbation exercises with elastic tubing
  • Four exercises including front pull, back pull, crossover and reverse crossover, performed 3 times per week. The standard protocol includes 3 sets of 15 repetitions with a resistance band while standing on the affected leg
  • Goal: to maintain alignment and stability
  • Outcome: balance improved in 4 weeks

Mobilisation

• Limited ankle dorsiflexion during jogging and walking gait is considered a risk factor for recurrent sprains because of the following:
  • Inability to reach the closed-packed position of the ankle joint during stance
  • Tendency to lock midfoot in supination
  • The centre of gravity moves laterally, thus the ankle joint becomes vulnerable to supination and a sprain

• According to Westad et al., mobilisation with movement (MWM) techniques used to treat peripheral joints were superior to a placebo, but not to other medical or physiotherapy interventions.
• The results of a systematic review and meta-analysis by Weerasekara et al. suggest that a mobilisation with movement intervention immediately benefitted patients with chronic ankle instability by increasing dorsiflexion range of motion.

Therapeutic Interventions

Mulligan’s mobilisation with movement (MWM) technique should include the following:

• Fibular glide at distal and proximal tibiofibular joint

• Talar glide

Helene Simpson also recommends using an MWM technique that includes midfoot mobility at the navicular.

Braces and Taping

Taping

• Hubbard and Cordova found that mechanical laxity decreased after applying tape.

• Delahunt et al. found no change in “actual” stability, but patients' perceptions of stability were significantly improved (56%).

• Hopper et al. found that Mulligan taping had no impact on neuromuscular control during static and dynamic balance.

Therapeutic Intervention

The following taping techniques were clinically assessed:

• Lateral subtalar sling (aimed at resisting subtalar inversion)

• Fibular repositioning, but the exact mechanism for reducing the incidence of sprains is unknown

• The application of the Kinesio Taping Method in preventing ankle sprains had no effect on muscle activation of the peroneus (fibularis) longus

Braces

No significant effect was found on function and balance when braces were applied. The following findings are of interest:

• Barlow at al. found that braces affect neuromuscular activity during walking, which can assist in decreasing sprains.
• Feger at al. investigated the effect of ankle braces on lower extremity muscle activities during functional exercises:
  • Forward lunge: reduction of muscle activity during pre‐initial contact in the lateral gastrocnemius and post‐initial contact in the peroneus longus.
  • Star excursion balance test: less muscle activity of the peroneus longus, lateral gastrocnemius, rectus femoris, and gluteus medius during balance anterior reach.
  • Anterior reach: significant reduction of the thigh muscles and total muscle activity.
  • Posterolateral reach: considerable reduction of gluteus medius activity.
  • Single limb eyes closed balance, star excursion balance posteromedial reach, or during lateral hop exercises: no differences between braced and unbraced conditions.

• Janssen et al. submitted a protocol to assess the effect of braces vs. neuromuscular exercises.According to their 2014 publication: "bracing was found superior to neuromuscular training in reducing the incidence but not the severity of self-reported recurrent ankle sprains after usual care".
• Fuerst et al. argued that individuals with ankle instability may benefit from a semi-rigid ankle brace to keep ankle inversion angles "in a range that is comparable to values of healthy people".

Therapeutic intervention

• Measurements to assess the effectiveness of using braces in patients with chronic ankle instability are not sensitive enough to assess dynamic stability.

• Helene Simpson suggests to continue to use braces:
  • Based on data from acute ankle sprains and prevention of recurrent sprains for one year post-injury
  • Cost-effectiveness and time efficiency

Flexibility and Strength Training

Flexibility:

Traditional concepts of flexibility exercises in chronic ankle instability include stretches of the soleus and gastrocnemius, performed 3 times for 30 seconds. A new protocol suggests including plantar fascia stretches and walking backwards. Helene Simpson recommends neural roll-down and toe extension stretches (flexor hallucis longus and big toe extension).

Strength:

A meta-analysis by Arnold et al. on concentric evertor strength deficits found:

• No cause and effect between deficits and loss of functional stability
• Not easy to detect evertor weakness
• Isokinetic testing at slow speeds might maximise differences

• Weakness of invertors

During strengthening exercises, muscle co-contraction is essential. Treatment protocols should include:

• Bilateral calf raises

• Short foot exercises

Strength is important and should be included in rehabilitation.

Example Treatment Protocol

Helene Simpson provides an example of her treatment protocol for the management of chronic ankle instability.

General Principles

1. Goal setting is critical
   • Team effort
   • The athlete takes on responsibility
2. Address postural stability
3. Include proximal stability, especially hip and knee joints
4. Focus on local stabilisers of the ankle and foot
5. Regaining dorsiflexion range of motion is a priority
6. Include cardio-vascular fitness
7. Integrate exercises into the gym to improve compliance
8. Assess footwear and sports-specific technique

Retraining medial ankle ligament

Phase 1

Cardio-vascular fitness to include:

• Cycling
• Hydrotherapy  or swimming
• Walk
  • Forwards and backwards
  • Ladder: stride length, “Pink Panther”, heel-toe, big toe, placing of the foot

Postural Control/ Balance exercises to include:

• 

  Tibialis posterior re-training
  Pilates
• Short foot exercises
• Tibialis posterior re-education

Strengthening exercises to include:

• Leg press
• Calf raises, theraband exercises
• Hamstring curls
• Bridging (glutes)
• Abdominal

• Neurodynamics and Flexibility

Lounges

Balance and proximal control

Phase 2

Cardio-vascular fitness

• Running
• Elliptical
• Stepper
• Rowing machine

Functional strength

• Modified lunges
• Squats: bilateral, single leg
• Single leg activity

Balance training

• Aeroplane, Star Excursion Balance Test
• Bosu ball, Balance pad, Wobble board

Shoe assessment

Phase 3

Cardio-vascular

• Sport-specific drills and skills
• Endurance
• Terrain

Balance/ function/ agility

• Jumping, skipping, landing
• Multiple hops
• Vertical jumps

Integration of sport specific activities, but without compromising the quality of movement.

Pain monitoring