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Figure 1: Lateral ligaments of the ankle joint. |
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Khan, K., & Bruker, P. (1998). Ankle acute injuries. In: Encyclopedia of Sports Medicine and Science, T.D.Fahey (Editor). Internet Society for Sport Science: http://sportsci.org. 7 March 1998.
Functional Anatomy
Clinical
Perspective
Lateral Ligament
Injuries
Medial Ligament
Injuries
Pott's
Fracture
Persistent Pain:
the "Difficult Ankle"
Osteochondral
Fractures of the Talar Dome
References
Ligamentous injuries around the ankle joint are among the most common sporting injuries especially in jumping sports (e.g., basketball, volleyball). They are not always well managed. Associated injuries are frequently not diagnosed and the rehabilitation of ligamentous injuries is often inadequate leading to a high rate of recurrence.
The ankle contains three joints. The talocrural or ankle joint is a hinge joint formed between the inferior surface of the tibia and the superior surface of the talus. The medial and lateral malleoli provide additional articulations and stability to the ankle joint. The movements at the ankle joint are plantarflexion and dorsiflexion.
The inferior tibiofibular joint the articulation of the distal parts of the fibula and tibia. The inferior tibiofibular joint is supported by the tibiofibular ligaments or syndesmosis. A small amount of rotation is present at this joint. The subtalar joint between the talus and calcaneus is divided into an anterior and posterior articulation separated by the sinus tarsi. The main roles of the subtalar joint are to provide shock absorption, to permit the foot to adjust to uneven ground and to allow the foot to remain flat on the ground when the leg is at an angle to the surface.
The ligaments of the ankle joint are shown in Figure 1. The lateral ligament consists of three parts: the anterior talofibular ligament (ATFL) which passes as a flat band from the tip of the fibula anteriorly to the lateral talar neck; the calcaneofibular ligament (CFL), which is a cord-like structure directed somewhat posteriorly; and the posterior talofibular ligament (PTFL), which runs posteriorly from the fibula to the talus. The medial or deltoid ligament of the ankle (not shown) is a strong, fan shaped ligament extending from the medial malleolus anteriorly to the navicular and talus, inferiorly to the calcaneus and posteriorly to the talus.
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Figure 1: Lateral ligaments of the ankle joint. |
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Inversion injuries are far more common than eversion injuries due to the relative instability of the lateral joint and weakness of the lateral ligaments compared to the medial ligament. Eversion injuries are seen occasionally. The strong medial ligament requires a greater force to be injured, therefore, these sprains usually take longer to rehabilitate. Ankle injuries are listed in Table 1.
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Table 1: Ankle acute injuries. |
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Common |
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Less Common |
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Uncommon but not to be Missed |
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The most important component of the assessment of ligamentous injuries is to determine the degree, if any, of instability present in the joint. This will determine the management of the injury. A comprehensive rehabilitation program is required in athletes with ligamentous injuries of the ankle if they are to return to their sport with full functional capacity and avoid recurrence of the injury.
Occasionally, other structures are damaged in addition to the ligaments. If these are not recognized and treated, prolonged pain and disability may result. These include fractures around the ankle joint, osteochondral fractures of the dome of the talus and dislocation of the peroneal tendons.
History
The mechanism of onset is an important clue to the diagnosis. An inversion injury suggests lateral ligament damage, an eversion injury medial ligament damage. The presence of a compressive component indicates the possibility of osteochondral injury.
At the time of the injury, the athlete may have heard a snap or tear. Unlike the significance of a 'snap' or 'pop' in an acute knee injury, this sensation is not of diagnostic significance
The location of pain will give an indication as to the ligaments injured. The most common site is over the anterolateral aspect of the ankle involving the ATFL. Occasionally in severe injuries, both medial and lateral ligamentous structures will be damaged.
Most ankle joint injuries are accompanied by swelling. The site of the swelling may give an indication of the location of the pathology, but the degree of swelling is usually, but not always a reliable indication of severity.
The degree of disability, both immediately following the injury and subsequently, is an important indicator of the severity of the injury. The initial management, the use of the RICE regimen and the duration of restricted weight bearing after the injury should all be noted.
A previous history of ankle injury and an assessment of the quality of the post-injury rehabilitation programme should be obtained. Subsequent use of protective tape and braces should be noted.
Examination
Examination of the ankle requires assessment of the degree of instability present and the grading of the ligamentous injury. Examination should detect functional disability such as loss of range of motion, reduced strength and reduced proprioception. For illustration of clinical examination the reader is directed to Clinical Sports Medicine pp 440-2
Investigations
X-ray including A-P, lateral and at least one oblique view should be performed after ankle sprains in situations where instability is present or when acute bony tenderness is present on the malleoli or the medial or lateral dome of the talus. X rays of the ankle joint must include the base of the 5th metatarsal to exclude associated fracture.
An osteochondral fracture may not be apparent on initial X-ray. If significant pain and disability are present despite appropriate treatment 4 - 6 weeks after an apparent 'routine' ankle sprain, specialist sports physician or orthopedic surgeon referral is indicated. A radioisotopic bone scan may be performed to exclude an osteochondral fracture.
Lateral ligament injuries occur in activities involving rapid changes in direction, especially on uneven surfaces. They are also seen when contact with another competitor's feet causes imbalance in jumping or landing. They are one of the most common injuries seen in basketball, volleyball, netball and most football codes.
In the typical inversion and plantarflexion injury, the three parts of the lateral ligament are usually damaged in order depending on the severity of the sprain. The ATFL is the first ligament damaged, followed by the CFL and finally the PTFL. Complete tear of all three ligaments results in a dislocation of the ankle joint and is frequently associated with a fracture.
In the assessment of lateral ligament injuries, each of the three components of the ligament must be examined and the overall degree of instability determined. Lateral ligament injuries are divided into three grades. Grade I corresponds to a minor tear with pain produced by stressing the ligament, but no laxity. Grade 11 injuries are painful on stressing the ligament and show some degree of laxity on examination, but have a firm end point. Grade 111 injuries show gross laxity without a discernible endpoint. Grading of these injuries gives a guide to prognosis and helps determine the rate of rehabilitation.
The usual mechanism of lateral ligament injury is inversion and plantarflexion. This may be accompanied by an audible snap, crack or tear. Depending on the severity of the injury, the athlete may have been able to continue activity immediately or have been forced to rest. Swelling usually appears soon after the injury, although occasionally it may be delayed some hours.
Treatment of lateral ligament injuries
The management of lateral ligament injuries of all three grades follows the same principles.
Initial Management
The initial management of lateral ligament injuries requires the RICE regimen. This is probably the single most important factor in treatment, particularly with Grade I and Grade II injuries. Many of the problems resulting from ankle sprains are due to the presence of blood and edema in and around the joint. This restricts the range of motion of the joint and can act as an irritant causing excessive synovial reaction. As well as ice, compression and elevation, it is important for the injured athlete to avoid factors which will promote blood flow and swelling, e.g. hot showers, heat rubs, alcohol, excessive weight bearing.
Reduction Of Pain And Swelling
Pain and swelling can be reduced with the use of electrotherapeutic modalities, e.g., TENS, interferential, magnetic field therapy. Analgesics may be required. Gentle soft tissue therapy and mobilization after the first 48 hours also may help to reduce pain. By reducing pain and swelling, muscle inhibition around the joint is minimized enabling range of motion exercises to be performed.
Restoration of Full Range Of Motion
The patient may be non weight bearing on crutches for the first 24 hours, but should then commence partial weight bearing in normal heel-toe gait. It will be necessary from this stage to protect the damaged joint with strapping or bracing. This will allow partial and ultimately full weight bearing without danger of aggravating the injury. Accessory and physiological mobilization of the ankle, subtalar and midtarsal joints should be commenced early in the rehabilitation process. As soon as pain allows, active range of motion exercises, e.g. stationary cycling, can be commenced.
Muscle Conditioning
Strengthening exercises should be commenced as soon as pain allows. Active exercises should be performed initially with gradually increasing resistance. Exercises should include plantar and dorsiflexion, inversion and eversion. Eversion strength is particularly important in the prevention of future lateral ligament injuries. Weight bearing exercises should be commenced as soon as possible.
Restoration Of Normal Proprioception
Proprioception is invariably impaired after ankle ligament injuries. Proprioceptive retraining exercises can be commenced early in the rehabilitation stage and should be gradually progressed from balancing on one leg to the use of the rockerboard or minitramp and ultimately to functional activities while balancing.
Functional Exercises
Functional exercises, e.g., jumping, hopping, twisting, figure-of-eight running, should be commenced when the athlete is pain-free, has full range of motion and adequate muscle strength and proprioception.
Return To Sport
Return to sport is permitted when functional exercises can be performed without pain during or after activity. While performing rehabilitation activities and upon return to sport, added ankle protection is required. This can be provided either with taping or bracing. As both seem equally effective, the choice of taping or bracing should be made on the grounds of patient preference, cost, availability and expertise in tape application.
Any athlete who has had a significant lateral ligament injury should have protective taping or bracing for all future sporting activities. There are a number of methods to protect against inversion injuries. The three main methods of tape application are stirrups, heel lock and the figure-of-six. Usually at least two of these methods are used.
Braces have the advantage of ease of fitting and adjustment, lack of skin irritation and reduced cost compared to taping over a lengthy period. There are a number of different ankle braces available. The lace-up brace is an effective ankle brace.
Treatment of Grade III Injuries
Treatment of grade III ankle injuries requires initial conservative management over a 6 week period. If the patient continues to make good progress and is able to perform sporting activity with the aid of taping or bracing and without persistent problems during or following activity, surgery may not be required. If however, despite appropriate rehabilitation and protection, the patient complains of recurrent episodes of instability or persistent pain, then surgical reconstruction of the lateral ligament, using one of the peroneal tendons or a fibular periosteal flap, is recommended. Following surgery, it is extremely important to undertake a comprehensive rehabilitation programme to restore full joint range of motion, strength and proprioception.
The indications for use of nonsteroidal anti-inflammatory drugs in ankle injuries is unclear. The majority of practitioners tend to prescribe these drugs in all cases of lateral ligament sprains although evidence of their efficacy in this condition is not convincing. However, it may be appropriate to commence medication 2-3 days following injury because of the risk of developing synovitis on resumption of weight bearing.
Medial ligament injuries do not occur as frequently as lateral ligament injuries because the deltoid ligament requires considerable force to be damaged. Occasionally they may be seen in conjunction with a lateral ligament injury. Medial ligament injuries may occur with fracture of the medial malleolus, talar dome or damage to articular surfaces. Medial ligament sprains should be treated in the same manner as lateral ligament sprains, although return to activity may be prolonged.
A fracture affecting one or more of the malleoli (lateral, medial, posterior) is known as a Pott's fracture. It can be difficult to distinguish clinically between a fracture and a moderate to severe ligament sprain. Both conditions may result from inversion injuries, with severe pain and varying degrees of swelling and disability.
The management of these fractures involves restoration of the normal relationship between the superior surface of the talus and the ankle mortise (inferior margins of tibia and fibula). If this relationship has been disrupted, internal fixation is required.
Isolated spiral fractures of the lateral malleolus (without medial ligament instability) and posterior malleolar fractures involving less than 25% of the articular surface are very stable. These fractures can be treated symptomatically with immobilization and crutches in the early stages for pain relief only.
Lateral malleolar fractures associated with medial instability, hairline medial malleolar fractures or larger undisplaced posterior malleolar fractures are potentially unstable, but may be treated conservatively. This involves a below knee cast extending to include the metatarsal heads. A walking heel may be applied after swelling has subsided (3-5 days). The cast should be worn for 6 weeks.
Displaced medial malleolar, large posterior malleolar, bimalleolar or trimalleolar fractures, or any displaced fracture which involves the ankle mortise, should be internally fixed. A comprehensive rehabilitation program should be undertaken following surgical fixation or removal of cast. The aims of the rehabilitation program are to restore full range of motion, strengthen the surrounding muscles and improve proprioception.
Persistent Pain After Ankle Sprain: the "Difficult Ankle"
In most cases of ligament sprain, the patient progresses satisfactorily through the rehabilitation process with reduction in pain and swelling and improvement in function. However, there is a significant group of patients who do not progress well and complain of persistent pain, swelling and impaired function without any indication of improvement 3-6 weeks after their injury. In these cases, it is important to consider the presence of one of the conditions listed in Table 2.
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Table 2: Causes of persistent ankle pain following acute injury. |
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An ankle ligament injury which is inadequately rehabilitated may present with persistent pain and loss of function. This usually occurs with increased activity levels. The common problems associated with inadequate rehabilitation are a loss of range of motion in the ankle joint (especially dorsiflexion), weakness of the peroneal muscles and impaired proprioception. Management involves restoration of full dorsiflexion by mobilization of the ankle joint, a programme of strengthening exercises for the peroneal muscles and proprioceptive exercises.
If rehabilitation has been appropriate and symptoms persist, it is necessary to consider the presence of other pathology. Symptoms of intra-articular pathology include clicking, locking and joint swelling. Examination may reveal effusion, bony tenderness or swelling at the sinus tarsi or peroneal tendons. The ankle should be re-assessed for evidence of chronic ligamentous instability.
Osteochondral Fractures of the Talar Dome
Osteochondral fractures of the dome of the talus which occur in association with ankle sprains are commonly overlooked. These fractures may occur when there is a compressive component to the inversion injury, especially with landing from a jump. The dome of the talus is compressed by the tibial plafond causing damage of the osteochondral surface. The fractures occur most commonly in the superomedial and the superolateral corners of the talus.
If large, these fractures may be recognized at the time of injury. The fracture site will be tender and may be evident on X-ray. Usually the fracture is not detected initially and the patient presents some time later complaining of an unremitting ache in the ankle, despite appropriate treatment for a ankle sprain. The patient often presents with a history of progressing well following a sprain, but then developing symptoms of increasing pain and swelling, stiffness and perhaps catching or locking as activity is increased.
Anderson, I.F., Crichton, J.K., Grattan-Smith, T., et al. Osteochondral fractures of the dome of the talus. J. Bone Joint Surg. 71A: 143-52, 1989.
Brukner, P. and K. Khan. Clinical sports medicine. Sydney: McGraw Hill, 1993.
Kannus, P. and P. Renstrom. Treatment for acute tears of the lateral ligaments of the ankle. J. Bone Joint Surg. 73A: 305-12, 1991.
Vegso, J.J., and E. Harman. Nonoperative management of athletic ankle injuries. Clin. Sports Med. 1: 85-98, 1982.
