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Ankle Instability

Acute Instability

The ATFL, which is the weakest of the three lateral ankle ligaments, is involved in the majority of lateral ankle sprains; the CFL is involved in 50% to 75% of such injuries and the PTFL in less than 10%.


Clinical assessment is based on the history of inversion and internal rotation of the foot. Examination is focussed on excluding the fracture and generally include swelling and localised tenderness on palpation.


Imaging starts from plain radiographs of the ankle in acute injuries.


First line of treatment is conservative and includes a combination of an ankle brace (2 – 4 weeks), appropriate pain management, rest, ice, compression, elevation and activity modification.

After the initial acute phase, functional recovery involves ROM exercises, strengthening, proprioception, and activity-specific training.

Majority of patients achieve a satisfactory resolution of symptoms in about 3 to 6 months.

Adequately treated ankle sprains have been shown to lead to a better outcome than an untreated sprain.


An RCT by Bleakley et al. compared an accelerated intervention including early therapeutic exercise and a standard regime with protection, rest, ice, compression, and elevation and showed that an accelerated exercise protocol during the first week after an ankle sprain improved ankle function.

Another RCT by Petrella et al. suggested that peri-articular injections of hyaluronic acid combined with standard care in acute grade I or II sprains were associated with reduced pain, more rapid return to sports, fewer recurrent ankle sprains and fewer adverse events for up to 24 months after injury when compared with a placebo injection of normal saline solution combined with standard care.

An RCT by Hupperets et al. showed that the use of a proprioceptive training programme after standard care of an ankle sprain was effective in the prevention of recurrent episodes in athletes who had sustained an acute sports-related ankle sprain.

In a study by Lamb et al. it was found that immobilisation in a below-knee cast or an Aircast boot for 10 days resulted in faster resolution of pain than if a patient was only given a tubular compression bandage.

In an RCT by Cooke et al. showed that a below-knee cast and an Aircast brace offered cost-effective alternatives to a simple tubular bandage in cases of acute severe ankle sprain; however, there were no differences in long-term outcome, therefore the treating doctor should consider the likely compliance and acceptability to patients when choosing a brace.

Proprioceptive training, compared with no intervention, is considered an effective way to reduce the rate of ankle sprains among male soccer players In a meta-analysis of RCTs, functional management was found to be associated with a higher percentage of patients returning to sports and higher rates of patient satisfaction compared to immobilisation with functional management for acute sprains.

In a systematic review of nine studies on functional management by Kerkhoffs, lace-up supports were found most effective, tapes were associated with skin irritation and elastic bandages were found least effective form of management.

A Cochrane review comparing surgical versus non-surgical management of acute ankle sprains found that all available trials had methodological flaws and it was not possible to demonstrate a clearly superior management option based on the available pooled data.


An RCT comparing surgery with functional management, found statistically significant differences in favour of surgical intervention in respect of pain, giving way and recurrent sprains at follow-up.

Chronic Instability

Chronic ankle instability refers to repeated episodes of instability that result in recurrent ankle sprains.


About 20% of acute ankle sprain patients develop chronic ankle instability. The failure of functional rehabilitation after acute ankle sprain leads to the development of chronic ankle instability. Patients usually complain of persistent pain and recurrent episodes of ‘giving way’.

Chronic ankle instability can be functional or mechanical. Functional instability depends on the patient-generated reports or complaints that could be accompanied by clinical laxity while mechanical instability can be identified by physical examination.


Other co-existent deformities including hindfoot varus, plantar flexion of the first ray, midfoot cavus, and generalised laxity may also contribute. Ligamentous laxity is more easily noticeable in chronic instability because of lesser amount of pain.


MRI is considered a useful modality to show associated pathologies, such as chondral injury, occult fractures, bone bruising, peri-articular tendon tears, degeneration, sinus tarsi injury, and impingement syndrome. The main signs of ligament injury on MRI scans are ligament swelling, discontinuity, a lax or wavy ligament, and non-visualisation.


Differentiation between functional and anatomical ankle instability is essential to guide an appropriate treatment.


The usual indication for surgery in chronic instability is a failure of conservative management and persistent symptoms. 


Surgical techniques include anatomical and non-anatomical repairs.


Anatomical repairs aim to restore normal anatomy and joint mechanics and seek to maintain movement of the ankle and subtalar joints.


However, the injured and attenuated ligament may not permit this type of repair.

The most commonly performed anatomical repair is the Broström-Gould repair that implies mid-substance imbrication and suture of the ruptured ends of the ligament augmented with the mobilised lateral portion of the extensor retinaculum, attached to the fibula after imbrication of the ATFL and the CFL.

Augmentation by internal brace system is becoming increasingly popular especially in revision case and high risk patients for failure (hypermobility, elite sportsmen). Failure of a standard repair usually occurs at the ligament to suture interface. Internal brace significantly decreases this potential failure, and hence aids in an accelerated rehab.


Non-anatomical repairs employ various types of local tendon graft in order to restrict movement, but without repair of the injured ligaments and result in altered biomechanics.

Non-anatomical repairs include Evans repair and Chrisman-Snook repair. The Evans method involves a distally-attached peroneus brevis graft through an oblique posteriosuperior drill hole in the distal fibula but does not replicate the ATFL or the CFL as it lies in a position in between these two ligaments. Chrisman and Snook described a weave intended to more closely approximate the ATFL and the CFL, incorporating a split peroneus brevis tendon graft in order to maintain some function of peroneus brevis.

A meta-analysis of seven RCTs was unable to reach a conclusion about the best surgical option for the management of chronic ankle instability. There was insufficient statistical significance and poor methodological quality of the randomised controlled trials that were available.


In one study with a small number of patients but with 26 years follow up, anatomic repairs revealed good and excellent results in 85% of patents.

Arthroscopic repairs are also in use and imply the reconstruction of autogenous plantaris tendon of the CFL and ATFL by using a 3-portal arthroscopic approach. For chronic ankle instability with no ligamentous repair, arthroscopic thermal capsular shrinkage is also recommended. Arthroscopy is also routinely performed as an adjunct to Broström-Gould procedure to look for and treat associated lesions.

The reported incidence of wound complications is about 1.6% after anatomic repair and about 4% after nonanatomic repair. Other complications include stiffness, recurrent instability, and nerve problems. Nerve-related problems account for 3.8% for anatomic repair and 9.7% for nonanatomic repair.


Long-standing instability and ligamentous laxity in addition to a cavovarus foot are among the risk factors for failure after surgery. Stiffness is common but can usually be tolerated. The loss of tibiotalar and subtalar motion can be caused by overtightening when performing nonanatomic tenodesis reconstruction. To treat subjective failure, physiotherapy is highly recommended. Late recurrent instability may be caused by minor chronic injuries while early recurrent instability may be caused by acute injury.

A systematic review by So et al. for standard repair reviewed 11 studies including 669 patients with a mean follow up of 8.4 years and revealed over 85% good functional results with a revision rate of 1.2%.

Another systematic review by Majeed et al. reviewed 10 studies including 343 elite athletes and showed a return to sports in 89% athletes at a mean of 16 weeks after surgical repair.

Augmentation with internal brace has been demonstrated to be at least as strong as the native ATFL in cadaveric models.

A retrospective review by Coetzee et al. compared the results of  augmentation repair with standard repair and reported that the former allowed an accelerated rehabilitation protocol with immediate weight-bearing and early range of motion.

A multicenter, prospective, RCT  by Kulwin et al. reported an average return to pre-injury activity levels 4.2 weeks earlier with brace than standard repair (12 vs 16 weeks).

However, Calder et al, in their study recommended that return to sport is not allowed until individuals can demonstrate 90% of pre-injury levels of strength, proprioception, and balance.

Accelerated Rehab


Ankle instability is common among general population and athletes.

First line of treatment is conservative with a combination of appropriate measures and functional rehab leading to satisfactory recovery in majority of individuals in about 6 months.

Persistent symptoms despite functional rehab warrant surgical repair, of which anatomic repair using Brostrom Gould technique remains the gold standard and provides good to excellent results.

Augmentation using internal brace provides excellent results and is recommended in high risks individuals and elite sports persons.

Physiotherapy rehab remains the key to achieve the intended outcomes.


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