Managing Chronic Pain After An Ankle Sprain
A patient presents to the office with a history of an ankle sprain that occurred eight months ago. The patient was playing tennis and rolled his ankle during the match. He had to immediately stop and felt a snap in the lateral ankle. For the next week, he wore a lace-up ankle brace and iced the ankle. He was able to walk on the ankle the day after the injury but had continued pain in the ankle that did not resolve for one month. At the one-month point, his doctor suggested the ankle was painful from the sprain and suggested a course of physical therapy. The patient performed all of the physical therapy sessions for over two months. At this point, he did report a slight improvement but the patient continued to experience pain with any form of exercise and the ankle was painful with prolonged standing. The patient dealt with the pain for two more months and then saw a second doctor. He suggested there was a probable tear of the lateral collateral ligaments and that the patient would need surgery for the repair of the ligaments. That physician did not obtain radiographs or a MRI and the patient now presents for a consultation about the ankle. What Does The Exam Reveal? Examination of the ankle shows light swelling of the anterolateral and lateral ankle. There is also mild swelling along the course of the peroneal tendons. The patient’s range of motion of the ankle is slightly tender with decreased dorsiflexion. The patient has tenderness with large circle motion of the ankle and mild pain along the course of the peroneal tendons with this activity. Upon palpation of the ankle, we note a tenderness along the anterolateral ankle about the anterior talofibular ligament. The patient also has pain in the region of the lateral gutter of the ankle joint. An anterior drawer test on the affected extremity is positive. The patient has normal muscle strength and there are no gross vascular or neurologic changes. We proceeded to obtain radiographs and stress radiographs of the ankle. The anterior drawer test and talar tilt stress tests for the affected extremity were slightly increased when we compared them to the contralateral ankle. However, we didn’t think this was the entire cause of the ankle pain. An MRI of the ankle revealed synovitis and scar formation of the lateral ankle joint with tenosynovitis and a possible longitudinal tear of the peroneus brevis tendon. We also noted a lateral deviation of the peroneal tendons from the posterior fibular groove. The MRI also revealed a region of cartilage and bone inflammation along the lateral aspect of the talus, which was suggestive of a possible osteochondral lesion. What Is The Differential Diagnosis? 1. Lateral ankle instability 2. Osteochondral lesion of the talus 3. Peroneal tendonitis or tendon tear 4. Synovitis and scar tissue in the ankle joint The diagnosis is fairly complex to address, especially with the type of results one sees on the MRI. In general, the most important findings of the MRI are the osteochondral lesion that has not resolved in the past eight months, the scar tissue on the lateral ankle and the peroneal tenosynovitis. The lateral ligament tear is of less concern. It is important to remember that an old tear of the collateral ligament will still show as a thickening or tear on MRI months after it is healed. One should also pay close attention to the gross instability on anterior drawer/varus stress tests and stress films more than the MRI reading. With regard to the peroneal tenosynovitis, there may be a tear of the tendon or an inflammation of the tendon that is secondary to the poor position of the tendon posterior to the fibula or from secondary guarding of the painful ankle. In this case, the position of the peroneal tendons not being posterior to the fibula and the involved peroneal inflammation are cause for concern. The osteochondral lesion is also of concern as is the lateral ankle scar tissue. This scar tissue is mainly caused by chronic joint inflammation, which is primarily due to the old torn ligament and cartilage damage. With so much information to digest, what is the proper treatment and how do you find out the true cause of the pain? In early cases, bracing and physical therapy with antiinflammatory medication is suggested, but in more advanced cases like this, surgical care is often the only option. What You Should Know About Surgical Treatment Our surgical care entails an arthroscopy of the ankle joint with debridement and removal of scar tissue with drilling of any osteochondral lesions. Keep in mind that deep lesions or medial lesions that are far posterior are difficult to reach and may require an open medial approach via an malleolar osteotomy, which is performed as a separate surgery. Following the arthroscopy, one should stress the ankle and check for laxity under fluoroscopy. If you note gross laxity, you should proceed to repair the lateral collateral ligaments through a modified Brostrom-type procedure. However, in order to check the lateral ankle ligaments and peroneal tendons, one should make a linear incision over the fibula. Doing so also allows you to examine the peroneal sheath and tendons. Pathology in the peroneal sheath may include subluxed or subluxing tendons, a peroneal longitudinal tear and a possible low lying muscle belly that is compressing the peroneal sheath. In the case of subluxation, the surgeon should deepen the peroneal groove through his or her choice of procedure. Keep in mind that you may not have to do all of the aforementioned procedures. However, with a complicated MRI finding such as the one discussed above, a complete surgical treatment with multiple options will decrease the chance of failure. Following surgery, have the patient wear a below the knee cast for two weeks and not place any weight on the foot during this time. The patient should subsequently perform passive range of motion exercises but continue to remain nonweightbearing for two additional weeks. Proceed to emphasize rapid physical therapy at the end of one month with two weeks of non-weightbearing therapy, and one to two additional months of stability and balance work. Final Notes With a complete course of therapy and a guarded return to activity, surgical procedures to correct lateral ankle instability can be particularly satisfying with excellent outcomes and very happy patients. However, it is essential to consider the true cause of pain and have options during surgery. If you prefer a step-wise approach, in cases of minimal laxity, you may pursue the arthroscopy prior to surgical exploration of the ankle ligaments and peroneal tendon. Dr. Baravarian is an Assistant Clinical Professor in the Department of Surgery/ Division of Podiatric Surgery of the UCLA School of Medicine. His e-mail address is Bbaravarian@mednet.ucla.edu.