Ankle Sprains: It’s not always “Just a Sprain”.
Unresolved Lateral Ankle Pain after an inversion type of ankle injury is often overlooked and misdiagnosed. Initial evaluation of ankle injuries should consist of detailed clinical history, meticulous anatomical clinical exam, plain films, and possible ultrasound/MRI if tendon injury, occult fracture, or osteochondral injury is suspected. Osteochondral lesions of the talus when detected early have a better chance of resolving with conservative treatment. Conditions that mimic lateral ankle sprain include impingement lesions, sinus tarsi syndrome, peroneal tendon pathology most commonly in the form of longitudinal tearing, tarsal coalitions, occult rear foot fractures, talocalcaneal sprains without or with instability, osteochondral lesions of the talus, and syndesmosis sprains.
In my experience the most common residual ankle pain post sprain is longitudinal tearing of the peroneal tendon. The second most common is sinus tarsi syndrome. The third most common is osteochondral lesion. On occasion a superficial peroneal nerve entrapment can be a source of residual pain as well. In my private practice, however, early diagnosis of longitudinal tearing of the peroneal tendon via clinical history, exam and ultrasound exam provides better long term outcome with earlier intervention. In addition osteochondral lesions are quite evident in the early stages of post sprain period and MRI and subtle plain film changes provide earlier intervention and minimize the need for surgical intervention. Sinus tarsi syndrome can usually be treated with cortisone injection and short period of immobilization of the subtalar and midfoot joint.
The importance of accurate and early diagnosis of ankle sprains cannot be overstated. True isolated ankle sprains will resolve quickly with appropriate periods of rest followed by rehabilitation and support. If co existing pathology is evident early diagnosis and appropriate treatment is imperative to minimize long term adverse sequela.