Nonsurgical Treatment of Acute and Chronic Ankle Instability


Introduction

Ankle sprains are common injuries in the athletic population, with an estimated 85% involving the lateral ligament complex. The lateral ligament complex consists of the anterior talofibular ligament (ATFL), posterior talofibular ligament (PTFL), and the calcaneofibular ligament (CFL). Cumulative data from a systematic review and meta-analysis estimated the incidence of ankle sprains at 12 per 1000 exposures based on the highest-quality studies reviewed, with athletes participating in indoor and court sports at greatest risk of injury. Moreover, a recent study of collegiate athletes found that at least 1 in 28 collegiate athletes sustains a lateral ankle sprain during each academic year, with the highest incidence in basketball and soccer. Duration of symptoms (acute versus chronic) helps treatment decision making; broadly, ankle instability can be managed nonsurgically (through short-term immobilization with bracing or casting and then early functional rehabilitation) or with surgery. This chapter will focus exclusively on the nonsurgical management of both acute and chronic ankle instability.

Acute Ligament Injuries

Diagnosis

Acute lateral ankle injuries most commonly occur following an excessive inversion and internal rotation of the hindfoot while the leg is in external rotation. Accurate diagnosis is achieved through careful history and physical examination including anterior drawer and talar tilt ankle ligament testing (with comparison to the uninjured side) ( Fig. 14.1 and ). Acute ankle injuries are commonly graded I to III, with higher grades indicating more injury to the lateral ankle ligament complex. However, there are multiple grading schemes offered in the literature, and grading may be difficult to assess in the acute setting, as specialized tests are poorly tolerated by patients. Fractures need to be identified when evaluating a painful foot or ankle. Ottawa ankle rules guide when radiographs are necessary, including when the patient is unable to tolerate weight bearing on the injured extremity or when there is tenderness at the medial malleolus, lateral malleolus, base of the fifth metatarsal, or navicular. Furthermore, the role for stress imaging in the acute setting to assess for excessive radiographic talar tilt has been debated. We do not routinely employ them in clinical practice.

Fig. 14.1, (A) Anterior drawer test. The foot is translated anteriorly with a grasp of the heel with the foot in slight plantarflexion. Counterpressure is applied to the anterior leg with the opposite hand. ( B) Talar tilt test. The foot is inverted with a grasp of the hindfoot with the foot in neutral dorsiflexion. By placing a finger on the lateral talar process one can more clearly discern ankle motion from subtalar motion.

Acute-Phase Treatment

The hallmark of treatment for an acute ankle injury involves early mobilization and a protocol of rest, ice, compression, and elevation (RICE). Rehabilitation after injury to the lateral ankle ligaments and surrounding tissues follows a continuum of care that is sensitive to the severity of injury and the injured tissues’ ability to tolerate stress. During the early phase of rehabilitation, injured tissues poorly tolerate stress. The goal of acute ankle sprain treatment is to optimize tissue healing by protecting injured tissues and providing an environment that promotes tissue healing.

Role for Immobilization

Ankle sprain severity helps to determine the type and duration of immobilization and weight-bearing limitations. Short-leg casts and nonweight-bearing restrictions are typically reserved for severe sprains or sprains that have impacted the integrity of the weight-bearing joint. Injuries that may require strict immobilization and nonweight bearing include grade III ankle sprains or perhaps more mild sprains in less compliant patients. In general, cast immobilization and/or protected weight bearing should be brief for acute ligamentous injuries—some authorities even recommend that it not exceed 10 days. However, immobilization duration differs in the presence of a fracture. Use of a walker boot and full weight bearing may be a reasonable consideration for patients with less severe ligament injuries and who might benefit from boot removal for range of motion (ROM) and active edema management. Rigid ankle braces are also suitable alternatives for immobilization ( Fig. 14.2 ). Assistive devices (i.e., crutches, walker, and knee scooters) might be indicated if patients cannot ambulate without a limp. Once patients can ambulate without a limp in either a walker boot or ankle brace, they then proceed to the next phase of rehabilitation.

Fig. 14.2, Lace-up ankle brace for ankle sprain.

As patients move to the next phase of rehabilitation, they may choose to maintain use of a supportive ankle brace or use ankle taping as they work through recovery. Taping has been shown in normal subjects with below-average proprioceptive scores to add proprioceptive feedback to ankles. Extrapolating this might suggest that a patient may feel better early in the recovery period after an acute ankle sprain when some of their proprioceptive feedback has been slowed relative to normal. Taping and bracing, however, should not be used as a substitute for the phases of rehabilitation reviewed below. These supportive tools can be used in conjunction with the rehabilitation protocol and should be weaned as a patient progresses through recovery and demonstrates return of proprioception and balance.

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