The ankle sprain that does not get better

Transcription

1 MODERN MEDICINE CPD ARTICLE NUMBER ONE: 1 point The ankle sprain that does not get better PETER LAM, MB BS (Hons), FRACS Chronic ankle symptom* following a sprain may l>e due to intrnurticuhir and/oi egtrftarticulur pathology of Lhe anblv. EffaCtive surgical treatments are available if the patient continues to be symptomatic' sifter nn appropriate course of physiotherapy. ^ Chronic ankle pain is usually the result of a prior ankle sprain. Chronic ankle symptoms following a sprain may be due to either or both of the following sources: residual symptoms from ankle joint pathology (eg instability, chondral or osteochondral injuries of the ankle, anterior ankle impingement) extra-articular pathology (eg peroneal tendon tear, peroneal tendon subluxation or dislocation, fracture of the anterior process of the calcaneus, lateral process of talus fracture and fracture of the base of the fifth metatarsal). Anatomy and mechanism of injury The fibula and its attached ligaments are the key elements in ankie stability. No shift of the talus, medially or lateral ligamentous structures are intact. The main lateral ligamentous restrains are the anterior talofibular ligament, calcaneofibular ligament and posterior talofibular ligament. The inferior extensor retinaculum also plays on important part. The Dr Lam is an adult orthopaedic foot and ankle surgeon at Mater Medical Centre, North Sydney; The Gallery, Chatswood; Sydney Academy of Sport, Narrabeen; Sydney Sports Medicine Centre, Olympic Park, Homebush; and St George Private Hospital, Kogarah, Australia. 8 MODERN MEDICINE OF SOUTH AFRICA / JANUARY 2003 anterior talofibular and the calcaneofibular ligaments work together to prevent inversion of the talus through the full range of ankle dorsiflexion and plantarflexion. Because of the orientation of the two ligaments, strain in the anterior talofibular ligament increases progressively as the ankle is plantarflexed during inversion. Strain in the calcaneofibular ligament is greatest when the ankle is inverted in dorsiflexion. Inversion of the plantarflexion foot produces a spectrum of injuries to the lateral ankle. These injuries are common in running sports such as soccer, basketball and netball. Depending on the severity of the injury, disruption begins with rupture of the anterolateral ankle joint capsule followed by the anterior talofibular ligament, and then the calcaneofibular ligament becoming involved with more severe injuries. Isolated calcaneofibular ligament rupture is possible without major injury to the anterior talofibular ligament. This occurs when there is an inversion injury with the ankle in a neutral or dorsiflexed position. Chronic ankle instability It is useful to consider chronic ankle instability in terms of functional and mechanical instability. Functional instability is the patient's subjective sense of the ankle giving way. This may be due to intra-articular ankle pathology resulting in pain which then causes the ankle to give way. Mechanical instability is the objective hypermobility of the ankle joint due to laxity of the lateral ligaments from previous ankle sprain(s). History-taking The patient will give a history of recurrent sprains. He or she may report a feeling of instability and not trusting the ankle, and will have difficulty walking on uneven terrain. There is discomfort with manoeuvres that involve sudden starting and stopping and pain with push-off activities such as running. There may also be pain and swelling with increased activity. Inspecting, palpating and testing On inspection, the ankle may be in varus alignment and this will predispose the patient to recurrent ankle sprains (Figure 1). On palpation, there may be localised tenderness along the ankle joint line (Figure 2) if there is associated injury to the articular cartilage. There may be tenderness along the anterior border of the lateral malleolus where the lateral ligaments (anterior talofibular and calcaneofibular) insert onto the fibula. The next step is to assess for laxity of the lateral ligaments. The anterior drawer test, which assesses laxity in the anterior talofibular ligament, is formed with the ankle in slight plantarflexion because this will unlock

2 I If the pain is anterior, articular surface injury and anterior ankle impingement should be considered. the ankle joint (Figure 3). One of the examiner's hands stabilises the leg, while the other hand draws the foot forward at the level of the heel. The test is considered positive if the ankle translates anteriorly by more than 1cm. This needs to be compared with the contralateral ankle in case the patient has generalised ligamentous laxity, in which case greater translation can occur before it is considered significant. Laxity in the calcaneofibular ligament is assessed by the talar tilt test. The test can be performed with the patient in a prone position with the knee flexed at 90. One hand stabilises the leg, while the other hand places a varus force on the heel (Figures 4a and b). The range of motion may be normal or slightly reduced. Peroneal muscle strength may be normal or reduced. Ankle pain following an inversion injury The patient can usually localise the pain to the anterior, posterior, medial or lateral aspects of the ankle. The pain may be associated with ankle swelling. This section discusses how history-taking, inspecting and palpating can suggest the different causes of pain at these sites. Anterior ankle pain If the pain is anterior, articular surface injury and anterior ankle impingement should be considered. Articular surface injury Articular surface injury may involve cartilage alone (chondral) or cartilage and subchondral bone (osteocondral). Patients with this type of injury will usually experience pain with walking, running and jumping activities. The pain is often worse with stairs or uneven ground. There may be start-up pain - where the patient has pain when he or she starts an activity such as running and the pain eases as the patient continues. With these lesions, the talar dome is more frequently injured than the tibia. Other symptoms may include ankle swelling, stiffness, weakness and giving way. On examination, there is tenderness along the ankle joint line. If it is a medial talar dome lesion, there will be maximal tenderness along the anteromedial aspects of the ankle joint line (Figure 2); if it is a lateral talar dome lesion, the tenderness will be along the anterolateral side (Figure 5). There may be an ankle effusion and lateral ligament laxity. Anterior ankle impingement With anterior ankle impingement, the pain is worse with walking or running up hills, inclines or stairs. Squatting (eg with weight lifting) and landing after a jump (eg in gymnastics or acrobatics) may make this pain worse. Sometimes the patient may be able to localise this pain to the anteromedial or anterolateral side of the ankle. There is a limited range of ankle motion, particularly in dorsiflexion. Anterior ankle spurs are the most common cause of anterior impingement (Figure 6). The cause of anterior spurs is unknown. They are most likely the result of repetitive minor injuries. Anterior impingement secondary to osteophyte formation is quite common in athletes, especially those who dorsiflex their ankles with force (such as runners, dancers and soccer players). There is a reported prevalence of 45% in football players and 59% in dancers. The spurs may occur along the anteromedial or anterolateral aspects of the distal tibia. They can also occur along the anterior aspect of the medial malleolus and may be a source of symptoms when they impinge on the talus. Lateral ankle pain Lateral ankle pain may be due to synovitis from recent sprain, peroneal tendon tear, peroneal tendon dislocation, or occult fracture (eg fracture of the anterior process of the calcaneus, the lateral process of the talus or the tuberosity of thefifthmetatarsal). Ankle synovitis Ankle synovitis can cause pain located just anterior to the lateral malleolus. The pain is usually worse with activities such as stair walking and running, and is relieved by rest. There may be associated ankle swelling or loss of joint motion. On examination, there is localised tenderness along the anterolateral joint line (Figure 5). There may be an ankle effusion and lateral ligament laxity. Peroneal tendon tear Peroneal tendon tear is commonly associated with lateral ligament instability. The peroneus brevis is more commonly torn than the peroneus longus. The tear is usually located at the level of the tip of the fibula. Such tears do not often present acutely but will present later with persistent lateral ankle pain and swelling. The pain is located behind the lateral malleolus, and it is worse with activity, especially on uneven ground. Patients who have persistent lateral foot or ankle pain and a history of an ankle sprain or injury may have a peroneus brevis injury, in which case examination will reveal tenderness along the course of the peroneus brevis tendon behind the lateral malleolus (Figure 7). There may be swelling due to tenosynovitis of the tendon. There may also be reduced strength in the peroneal tendons (tested by active eversion of the foot against resistance) which may be associated with pain. Peroneal tendon dislocation Skiing is a common cause of peroneal tendon dislocation. It is due to forceful contraction of the peroneal tendons as the skier edges the skis into the snow while JANUARY 2003 / MEDICINE OF SOUTH AFRICA 9

3 Chronic symptoms after ankle sprain continued Peroneal tendon tear I is commonly associated with lateral ligament instability. The symptoms are worse on uneven ground. Examination may reveal swelling and tenderness along the peroneal tendons. Active circumduction of the ankle may recreate the symptoms. Resisted eversion with the ankle in maximal dorsiflexion will cause the tendons to dislocate (Figure 8). Figure 1 (above). Hindtoo! varus alignment may predispose to recurrent lateral ankle sprains. Figure 2 (right). Tenderness along the anteromedial ankle joint line. Figure 3 (above). Anterior drawer test to detect anterior talofibular ligament rupture. making a turn. The patient will often experience a popping sensation during the accident. The peroneal tendons may remain dislocated, or they may reduce and dislocate repeatedly with further activities. There is posterolateral ankle pain and swelling behind the lateral malleolus. With repeated dislocations, the patient will feel a snapping or popping sensation. Occult fractures Anterior process of calcaneus fracture can happen with a lateral ankle sprain. It occurs when the foot is adducted and plantarflexed. It is an avulsion fracture of the bifurcate ligament. The patient presents with persistent lateral ankle pain following an ankle sprain. The pain and the tenderness are maximal in the region of the sinus tarsi, which is about 2cm anterior and 1cm inferior to the tip of the lateral malleolus (Figure 9). Lateral process of the talus fracture is also known as the snow boarder's fracture. The patient presents with localised pain, swelling and bruising anterior to the lateral malleolus. Clinically, the fracture appears like a lateral ankle sprain. Because of this, and the fact that plain x-rays often do not show the fracture clearly, the fracture is frequently diagnosed late in patients who have had a presumptive diagnosis of an ankle sprain. The symptoms do not resolve with physiotherapy and the patient presents with chronic lateral ankle pain. Tuberosity of the fifth metatarsal fracture follows an inversion injury to the ankle and can be associated with an ankle sprain. It is an avulsionfracture of the fifth metatarsal tuberosity, which is where the peroneus brevis tendon inserts. The patient complains of lateral ankle and midfoot pain. Examination reveals tenderness over the base of the fifth metatarsal (Figure 10). Figures 4a and b. Tatar tilt test to detect calcaneofibular ligament laxity. a (left). One hand stabilises the leg. b (right). The other hand places a varus force on the heel. Posterior ankle pain Posterior ankle pain may be due to posterior ankle impingement. 10 MODERN MEDICINE OF SOUTH AFRICA / JANUARY 2003

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5 Chronic symptoms after ankle sprain continued Tu berosity of the fifth metatarsal fracture follows an inversion injury to the ankle and can be associated with an ankle sprain. W = Figure 7. Tenderness along the peroneus brevis tendon behind the lateral malleolus. 12 MODERN MEDICINE OF SOUTH AFRICA / JANUARY 2003 Figure 5 (left). Tenderness along the anterolateral ankle joint line. Figure 6 (above). Anterior impingement lesions of the tibia and talar neck. Posterior ankle impingement There are several causes of posterior ankle impingement. It may be due to the presence of an os trigonum - the ununited posterolateral tubercle of the talus. Its prevalence is about 10% and it occurs bilaterally in up to 50% of cases. The os trigonum is usually asymptomatic; if it is symptomatic, the severity of symptoms is not in proportion to its size. It may become symptomatic after a lateral ligamentous injury because of disruption of the fibrocartiliginous connection between the os trigonum and the posterolateral process of the talus. A trigonal or Steida process is an abnormally large posterolateral tubercle of the talus. It may become symptomatic after a lateral ligament sprain because it allows increased rotation, causing impingement with full piantarflexion of the ankle. Other causes of posterior ankle impingement include: soft tissue entrapment (scar tissue or pseudomeniscus after an ankle sprain); advanced lateral ligament instability resulting in tibiocalcaneal abutment when the patient Figure 8. Ankle e vers ion against resistance in the dors/flexed position has caused the subluxmg peroneal tendons to dislocate. goes into full ankle piantarflexion; and impingement from anomalous muscles. Posterior ankle impingement occurs most commonly in female ballet dancers who place the ankle in extreme equinus to assume the en pointe position. It occurs less frequently in other athletes after ankle sprains. Patients will complain of pain in the area of the posterior heel or deep in the back of the ankle. Sometimes they can localise the pain to the posterolateral aspect of the ankle. The symptoms are aggravated by pointe work or jumping activities. On examination, there is tenderness with deep palpation in the posterolateral and, to a lesser extent, posteromedial aspects of the ankle. A posterior impingement test with be positive fie passive full piantarflexion of the ankle recreates the pain). Investigations The investigative options for sports-related injuries of the foot and ankle include x-rays taken while the patient is weight bearing, bone scan, CT scan, MRI scan and ultrasound. Standard anteroposterior, lateral and oblique x-rays should be performed in all patients who present with either chronic ankle instability or chronic pain following ankle sprains. All foot and ankle x-rays should be done with the patients bearing weight unless they are unable to because of pain (eg with recent injury). Weightbearing x-rays are important because they will demonstrate any malalignment or deformity and allow assessment of the severity of any associated arthritis. In patients who present with chronic ankle instability without ankle pain, weight-bearing x-rays should be performed to look for associated injuries such as osteochondral lesions of the talar dome. Stress x-rays are not usually required because laxity in the lateral ankle ligaments can be appreciated clinically. (The

6 Plain x-rays often will either not show the fracture of the lateral process of the talus or have only subtle changes. anteroposterior stress x-ray is an x-ray done during the talar tilt test, and the lateral stress x-ray is done during the anterior drawer test.) Ankle x-rays, in particular the lateral x-ray, will frequently demonstrate the anterior osteophyte in the distal tibia and talar neck (Figure 6) in patients with anterior ankle impingement symptoms. Plain x-rays often will either not show thefractureof the lateral process of the talus or have only subtle changes (Figure 11a). Thus a high index of suspicion is required to diagnose this injury. If the fracture is suspected, a bone scan may be performed, but a CT scan is the ideal investigation to visualise thefracture (Figure lib). Standard x-rays of the foot will reveal a fracture of the tuberosity of the fifth metatarsal. The fracture may extend into the fifth metatarsocuboid joint. It is often undisplaced or minimally displaced. The oblique foot x-ray is often the most helpful in identifying fracture of the anterior process of the calcaneus. If the x-rays are not helpful, a bone scan should be performed. In patients who have posterior ankle impingement, plain x-rays may reveal the presence of an os trigonum or trigonal process. Bone scans are very useful in patients with marked tenderness and pain but normal foot and ankle x-rays. The bone scan may reveal a fracture such as an anterior process of the calcaneus fracture. A bone scan also be helpful in localising the pathology in patients with talar dome osteochondral lesions, anterior ankle impingement pain and posterior ankle impingement pain. Ultrasound can identify tears of the peroneal tendons. However, the reliability of the ultrasound result is operator dependent. An MRI scan is a more useful investigation for the assessment of soft tissue injury because it can also identify other associated injuries in the ankle such as chondral or osteochondral injuries to the talar dome. MRI scans are very helpful in investigating patients with chronic pain of unknown aetiology because the MRIs can detect changes in the cartilage and bone (chondral or osteochondral lesions of the talar dome, posterior ankle impingement) and tendons (peroneal tendon tear or dislocations), and synovial impingement. A CT scan is most helpful in the assessment of patients with suspected lateral process of talus fractures. It can also be useful in the patient who has suspected osteochondral lesions of the talar dome. However, an MRI scan can provide more information regarding the stability of the osteochondral lesion. Management Chronic ankle instability Active rehabilitation is the mainstay of treatment for chronic ankle instability. This involves physiotherapy that concentrates on range-of-motion exercises, peroneal muscle strengthening (Figure 12) and proprioceptive retraining (Figure 13). Bracing may be helpful. Orthotics or a lateral heel wedge to correct varus hindfoot alignment may help to prevent reinjury in patients with this malalingment. Most (80%) ankle sprains recover completely with conservative treatment. If the patient continues to have ankle instability despite conservation treatment, surgery is indicated. The aim of the operation is to restore the length of (ie shorten) the elongated anterior talofibular and calcaneofibular ligaments. After surgery, the patient may be able to weight-bear in an ankle brace. Physiotherapy commences two weeks after the operation; this allows a more rapid return to function and sports. The use of plaster cast can delay rehabilitation and return to activities. Ankle pain after an injury The initial treatment of patients with anterior, lateral or posterior ankle pain after an injury is physiotherapy and avoidance of activities that aggravate the symptoms, such as running and jumping sports. Injection of local anaesthetic and corticosteroid may be helpful in patients with synovitis or posterior ankle impingement. Wearing shoes with a 1 to 1,5cm heel lift can help with anterior ankle impingement pain. If the pain persists despite a trial of physiotherapy (up to three months) or if the improvement plateaus, further investigation is required, with possible surgery JANUARY 2003 / MEDICINE OF SOUTH AFRICA 13

7 Chronic symptoms I Active rehabilitation is the after ankle sprain I mainstay of treatment for continued chronic ankle instability. Figure 1 la and b a (left), Anteroposterior x-ray suggesting a fracture of the lateral process of the talus, b (above). The fracture was confirmed on the coronal CT scan. required; this can vary from wearing sneakers with a compressive tubigrip to using a walking cast or boot. Only rarely will the fracture be sufficiently displaced to require open reduction and internal fixation. There may be discomfort in the region of the fracture for up to three months after injury. Peroneal tendon dislocation In acute peroneal tendon subluxation or dislocation, nonoperative treatment with immobilisation is ineffective. Surgical repair of the peroneal retinaculum is required to stabilise the tendons. Conclusion depending on the clinical findings. Exceptions to this are if the patient has a fracture or if there is a peroneal tendon subluxation or dislocation; these are discussed below. Occult fractures As mentioned above, a fracture of the anterior process of the calcaneus can initially be missed on x- ray until a bone scan is done. With early diagnosis, a short-leg walking cast for six weeks will allow thefractureto heal. If the diagnosis is delayed, then a trial of a walking cast or boot for six weeks is helpful. The patient will often have discomfort in the region of thefracturefor up to three months II m ^ m b - V 1 * V- - ^C*- * - Figure, «~ 12. V* Peroneal muscle s * V.V-. strengthening with the use of a theraband. 14 MODERN MEDICINE OF SOUTH AFRICA / JANUARY 2003 after the injury. If the pain persists, surgical excision of the fracturefragmentmay be necessary at a later stage. In a patient with a fracture of the lateral process of the talus, displacement of the fracture (as seen on CT scan) will determine if surgery is required. If a displaced lateral process of talus fracture is left untreated, it may lead to the development of painful post-traumatic arthritis in the subtalar joint. This can develop within 12 months of the injury. The tuberosity of the fifth metatarsal has an excellent blood supply, and a fracture there will heal readily. Symptomatic treatment is usually all that is Figure 13, Proprioceptive retraining using a balance board, Causes of chronic ankle pain after an ankle sprain can be divided into two groups: intra-articular pathology (instability, chondral or osteochondral injuries in the ankle, anterior ankle impingement, posterior ankle impingement) and extra-articular pathology (peroneal tendon tear, peroneal tendon dislocation, fracture of the anterior process of calcaneus, lateral process of talusfracture,fracture of the base of the fifth metatarsal). It is important to determine the cause of the symptoms because this will allow the most effective treatment. CPD questions appear on page 15 In Summary Ankle sprains don't always get better on their own. -1( chronic ankle Instability follows a sprain, look for laxity in the lateral ligaments. Active rehabilitation Is the mainstay of treatment If chronic ankle pain follows a sprain, careful examination and Investigation may reveal pathology in or around the ankle Joint. - Physiotherapy is often the firstline treatment tor ankle pain If a trial of physiotherapy falls, effective surgical treatments are available

8 QUESTIONS FOR CPD ARTICLE NUMBER ONE CPD: 1 point The ankle sprain that does not get better Instructions 1. Before you fill out the computer answer form, mark your answers in the box on this page. This provides you with your own record. 2. The answer form is perforated and bound into this journal. Tear it out carefully. 3. Read the instructions on the answer form and follow them carefully. 4. Your answers for the January issue must reach MODERN MEDICINE, POBox 2271, Clareinch 7740, by April , 5. You must score at least 60% in order to be awarded the assigned CPD points. Answer true or false to parts (a) to (e) of the following questions. Part 1. The following statements relate to ankle injuries: a. Strain in the anterior talofibular ligament increases as the ankle is plantarflexed during inversion. b. Rupture of the calcaneofibular ligament is not possible without major injury to the anterior talofibular ligament. c. Most ankle sprains recover completely with conservative treatment. d. Varus alignment of the ankle may predispose to recurrent lateral ankle sprains. e. A positive anterior drawer test indicates laxity in the anterior talofibular ligament. Part 2. Regarding the clinical features on ankle injuries: a. Pain with push-off activities, such as running, is a feature of chronic ankle instability. b. Anterior ankle impingement due to osteophyte formation is quite common among dancers and soccer players. c. A 'snow boarder's fracture' is a fracture of the lateral process of the talus. d. Fracture of the lateral process of the talus invariably causes swelling posterior to the lateral malleolus. e. Posterior ankle impingement is common in female ballet dancers. Part 3. Regarding the investigation of ankle injuries: a. Patients who present with chronic pain following ankle sprains should have x-rays performed. b. All foot and ankle x-rays should be performed with the patient supine (non-weight-bearing). c. When there is chronic ankle instability without ankle pain, stress x-rays are always required to demonstrate laxity in the lateral ankle ligaments. d. A bone scan may be performed if a fracture is suspected and the x-ray is normal. e. An ultrasound is the most useful investigation for the assessment of soft tissue injury. Part 4. In the management of ankle injuries: a. The initial treatment of chronic ankle pain after a sprain is usually physiotherapy. b. Orthotics may be helpful in preventing reinjury in patients with varus hindfoot alignment and recurrent ligament sprain. c. A local corticosteroid injection may be helpful in patients with posterior ankle impingement. d. A displaced lateral process of talus fracture may be treated with active exercises. e. A fracture of the tuberosity of the fifth metatarsal may be treated symptomatically. CPD Article 1 See tear-out sheet for details. Part 1 Part 2 Part 3 Part 4 a a a a b b b b c c c c d d d d SffiS e e e e JANUARY 2003 / MODERN MEDICINE OF SOUTH AFRICA 15