A sprained ankle is one of the most common orthopedic injuries. In the United States more than 25,000 such injuries occur every day. Although most ankle sprains resolve completely, chronic residual ankle symptoms still persist in about 20% to 40% of treated patients. We will outline potential causes of persistent pain after an ankle sprain.
What is an Ankle Sprain?
A sprain is actually an injury to the ligaments of the ankle joint, which are elastic, band-like structures that hold the bones of the ankle joint together and prevent excess turning and twisting of the joint (fig 1). In normal movement, the ligaments can stretch slightly and then retract back to their normal shape and size. Sprained ankles often result from a fall, sudden twist, or a blow that forces the ankle joint out of its normal position. Ankle sprains commonly occur while participating in sports, wearing inappropriate shoes, or walking or running on an uneven surface. The anterior talofibular ligament is one of the most commonly involved ligaments in this type of sprain. Approximately 90% of ankle sprains are inversion injuries.
Diagnosis of Ankle Sprain
Patients who sustain ankle sprains present with pain or soreness over the injured ligaments, loss of function, swelling, bruising, difficulty walking, and or stiffness in the joint. These symptoms may vary in intensity, depending on the severity of the sprain. A severe sprain may be diagnosed in patients who report hearing or feeling a popping sensation, followed by immediate swelling and the inability to walk or finish their athletic endeavor after an inversion injury. In evaluating your injury, the orthopedic surgeon will obtain a thorough history of your symptoms followed by a lower extremity examination. X-rays or other advanced imaging studies may be ordered to help determine the severity of the injury.
The goal of treating ankle sprain is to prevent chronic pain, instability, and disability. The first phase of routine ankle sprain treatment consists of rest, ice, compression, elevation, and usually the use of anti inflammatory medications. We recommend an air cast for a low-grade ankle sprain while a severe sprain will require longer immobilization utilizing a walking boot or a short leg cast for three weeks.
The amount of therapy that a person can handle will depend on their level of pain and the grade of sprain they experienced. It is not recommended to return to sports or extreme physical activities until hopping on the ankle is achieved without pain. Wearing high-top tennis shoes may also help prevent ankle sprains if the shoes used are laced snug and if the ankle is taped with a wide, non-elastic adhesive tape.
Residual Pain after Ankle Sprains
Ankle pain not responding to treatment, stiffness, locking and catching swelling, giving way, and numbness may persist several months following an ankle sprain. A careful patient history and physical examination is needed to assess the presenting complaint, mechanism of injury, level of activity, and exact location is paramount in delineating potential etiology.
The orthopedic surgeon must rule out missed diagnosis and associated injuries at the time of initial ankle sprain (table 1). A partially treated or untreated ankle sprain may lead to chronic ankle instability, a condition marked by persistent discomfort and a “giving way” of the ankle. Weakness in the leg may also develop. Improper or insufficient rehabilitation may lead to impaired neuromuscular control, impaired proprioception and postural control.
Persistent pain with catching or locking in the ankle joint could be related to damage to the cartilage with intraarticular loose bodies within the ankle joint or an osteochondral defect (fig 2). Pain on direct palpation of bony prominences in the leg ankle and foot may indicate missed fractures at the time of initial injury (table 1). Palpating for the area of maximal tenderness along the tendons and directly over the syndesmosis can rule out peroneal tears and chronic high ankle sprains. In teenagers with persistent ankle pain and recurrent ankle sprains the foot should be examined for stiffness of the joint below the ankle to rule out “tarsal coalition” – a condition characterized by abnormal fusion of foot bones.
Burning or shooting pain, numbness and tingling may indicate stretch injury on the cutaneous nerves surrounding ankle either from significant twisting at the time of initial sprain or from chronic swelling of the ankle. This condition in my experience leads to prolong recovery requiring 9 to 12 months for complete resolution of symptoms.
Magnetic resonance imaging (MRI) evaluation is particularly useful in demonstrating chondral injury, bone bruising, radiographically occult fractures, sinus tarsi injury, tendon tears, degeneration, and impingement syndrome.
The initial management of chronic ankle instability is a robust structured program of functional and prophylactic rehabilitation. Failed rehabilitation is an indication for surgical repair.
While ankle sprains are very common injuries seen by orthopedists and general practitioners alike, appropriate three-phase functional rehabilitation can provide excellent results with minimum comorbidities. When symptoms persist after several months the examining physician must assess for potential missed diagnosis, inadequate ankle rehabilitation and associated injuries.