I. Overview
Ankle sprains are one of the most common injuries. Most patients with ankle sprains are younger than 35 years old, usually 15-19 years old, with an incidence of 10%-30% in young athletes. The incidence of ankle sprains varies from sport to sport.
Pain, swelling, stiffness, and instability remain in 59% of ankle sprains, and the presence of these symptoms results in limited activity, with most patients experiencing a decrease in their pre-injury level of motion and even limitations in their daily life after the injury. In nearly 40% of patients, the ankle joint is unstable and prone to repeated sprains and pain, and in severe cases, inversion or valgus deformity. The incidence of lateral instability combined with articular cartilage injury is 55%, with cartilage injury to the talus being the main cause, mostly on the medial surface of the talus, but the rate of lateral articular cartilage injury is also increasing significantly, and the incidence of medial instability combined with cartilage injury is 98%. Cartilage injury is one of the main causes of pain left by ankle sprains, and other causes such as soft tissue impingement and synovitis are also important. Therefore, it is crucial to correctly diagnose and reasonably treat ankle ligament injuries.
Anatomy
(a) Medial collateral ligament: The medial collateral ligament, also known as the triangular ligament, stabilizes the medial side of the ankle joint from front to back in a fan shape and is the strongest ligament of the ankle joint. The deltoid ligament is divided into two layers, the deep layer plays a more important role. The superficial layer includes the navicular tibial ligament and the heel tibial ligament. The deep layer connects the lower surface of the tip of the medial ankle to the medial aspect of the talus and includes the anterior talofibular ligament and the posterior talofibular ligament. The main function is to prevent excessive abduction and valgus of the ankle joint and the subtalar joint, and to limit the valgus, anterior rotation and anterior displacement of the talus.
(2) Lateral collateral ligament: The lateral collateral ligament consists of three bundles, which are the anterior talofibular ligament, the heel-fibular ligament and the posterior talofibular ligament from anterior to posterior. The main role is to limit the anterior displacement and inversion of the talus.
The anterior talofibular ligament starts from the anterior border of the outer ankle and ends at the lateral aspect of the talar neck in a forward oblique line, 2-2.5 mm thick. The main role is to limit the anterior displacement of the talus.
2, heel peroneal ligament: from the tip of the outer ankle, and stop at the lateral side of the heel bone in a posterior oblique line, located in the deep side of the peroneal long and short tendons. The main function is to limit the inversion of the heel bone.
3.Posterior talofibular ligament: it starts from the posterior part of the external ankle fossa and ends at the posterior lateral process of the talus horizontally and posteriorly, which is the strongest of the 3 bundles. The main function is to limit the posterior displacement of the talus.
C. Acute injury of ankle ligament
Acute injury of the ankle ligament is a very common sports injury, and has the highest incidence among joint ligament injuries. Among them, the lateral collateral ligament injury is the most common.
(A) Acute injury of the lateral collateral ligament
1. Mechanism of injury: posterior rotation injury is the most common mechanism of injury. The anterior talofibular ligament rupture is the first to rupture in posterior rotation injury of the ankle; if the injury violence persists, the heel-fibular ligament ruptures subsequently; the posterior talofibular ligament rarely ruptures. Simple valgus injury can also lead to rupture of the lateral collateral ligament.
2, injury pathology: because the ligament is actually a thickened part of the joint capsule and constitutes the bottom of the fibular sheath of the peroneal tendon, ligament rupture is mostly combined with blood accumulation in the ankle joint and peroneal tendon sheath at the same time. When the ligament is completely ruptured, the joint cavity is connected to the peroneal tendon sheath, and pressure on the accumulated blood in the joint cavity will cause the peroneal tendon sheath to bulge, which is diagnostic for complete ligament rupture. According to the different degrees of ligament rupture, the injury can be divided into 3 degrees. degree I injury refers to ligament strain, no instability of the joint. degree II injury refers to partial rupture of the ligament, mild instability; complete rupture of the ligament is degree III injury, combined with obvious instability.
3. Diagnosis and differential diagnosis.
(1) Symptoms: swelling and pain of the lateral soft tissue after ankle sprain, with petechiae in severe cases, accompanied by different degrees of activity limitation. In severe cases, the affected side cannot walk with weight.
(2) Physical signs.
(1) Pressure pain: The pressure pain points are mainly on the lateral side of the ankle joint, where the anterior talofibular ligament and the heel-fibular ligament are located. When looking for pressure pain points, attention should be paid to the examination of joint injuries. Examination of pressure points should include: anterior talofibular ligament, heel-fibular ligament, posterior talofibular ligament, tarsal sinus ligament, heel dice ligament, metatarsal dice ligament, posterior talofibular triangle, paracarpal and anterior talofibular ligament. The palpatory sign is to first locate the lateral depression of the talofibular joint, the tarsal sinus. The anterior talofibular ligament is the line between the upper outer edge of the tarsal sinus and the tip of the outer ankle; the deep side of the abdominal aspect of the short toe extensor muscle is the heel dice joint; the base of the 5th metatarsal is the stopping point of the short fibular muscle, and the metatarsal dice joint can be palpated by finding this point. After the main signs are found, it is easy to diagnose whether the ligament is damaged.
② foot rotation test: repeat the injury action, the foot is passively rotated back, the corresponding injury site on the lateral side is painful. If the medial side of the ankle is painful, it suggests a paramedian navicular injury, or a medial deltoid ligament injury.
③ Front drawer test: The purpose is to check whether the lateral collateral ligament is completely ruptured. The examiner holds the distal calf with one hand and the heel with the other, causing the talus to stagger forward. The two sides are compared, and if the range of misalignment on the injured side is larger, it is positive. This test is usually easiest to perform in the mild plantar flexion position of the ankle. It has also been suggested that a positive drawer test in neutral ankle position indicates a complete rupture of the anterior talofibular ligament and a positive drawer test in plantarflexion indicates a complete rupture of the heel-fibular ligament.
Internal rotation stress test: If the ankle is passively turned inward, a positive test is performed if the injured ankle has a greater “opening” in the lateral joint space. This means that the anterior talofibular ligament or/and the heel-fibular ligament is completely ruptured.
Combined injury: Lateral collateral ligament injury is often combined with other tissue injuries in the foot and ankle, including tarsal sinus ligament injury, deltoid ligament injury, paracarpal injury, posterior talar deltoid injury, talar osteochondral tangential fracture, and heel dice joint injury.
4.Auxiliary examination: including ankle X-ray, arthrography and MRI.
(1) X-ray: including anterior-posterior, lateral, ankle point and stress position of the ankle joint. The anteroposterior and lateral positions are used to exclude ankle fractures and avulsion fractures of the ligament stops; the ankle point position can exclude injuries to the inferior tibiofibular ligament; the stress position can be used to determine the extent of lateral collateral ligament injuries. The inversion stress position X-ray can measure the tilt angle of the talus. If the tilt angle is greater than 5 degrees compared to the contralateral side, it suggests a rupture of the lateral collateral ligament. The anterior drawer stress x-ray can measure the anterior displacement of the talus. The anterior displacement of the talus in the normal ankle joint is no more than 3mm. If the anterior displacement of the talus is greater than 3mm, it indicates a rupture of the lateral collateral ligament. The anterior drawer stress position X-ray can show whether the talus has an anterior subluxation, which has a greater diagnostic significance than measuring whether the anterior distance of the talus is greater than 3mm.
(2) Arthrography or tenascopy: This is used to diagnose a complete rupture of the ligament. When the anterior talofibular ligament is completely ruptured, the contrast agent injected into the joint cavity will leak into the subcutaneous tissue. Since the heel-fibular ligament is involved in forming the base of the peroneal tendon sheath, intra-articular contrast will enter the peroneal tendon sheath in the event of a complete rupture of the heel-fibular ligament; conversely, if contrast is injected into the tendon sheath, it will enter the joint cavity in the event of a rupture of the heel-fibular ligament. Since these tests are invasive and have a high rate of false positives and false negatives, they do not need to be performed routinely.
(3) MRI: Axial films in neutral or dorsal extension 10 degrees of the ankle joint can clearly show the anterior talofibular ligament and the posterior talofibular ligament. The normal MRI image of the anterior talofibular ligament is a striated, homogeneous low signal, whereas the posterior talofibular ligament is a wider, slightly scalloped, inhomogeneous signal. The talofibular ligament is best defined on axial or coronal views in plantarflexion of the ankle joint and appears as a low-signal band. In the acute injury stage, there may be lamellar high signal in the low signal ligament, interruption of ligament continuity, surrounding soft tissue edema and joint cavity effusion, etc.
5.Differential diagnosis: pay attention to differentiate from external ankle fracture, talar osteochondral injury, heel anterior process fracture, peroneal tendon rupture or dislocation.
6.Treatment: Determine the treatment plan according to the stability of the joint. The purpose of treatment is to restore the patient to the pre-injury level of movement as soon as possible and to the greatest extent possible.
(1) Conservative treatment: Applicable to cases without instability or mild instability of the ankle joint. In the acute stage, ice, compression bandage, rest (braking the affected limb) and elevation of the affected limb should be applied; after the pain is relieved, active movement of the ankle joint can be attempted, walking with weight gradually and muscle strength exercises can be performed; after the pain disappears, muscle strength exercises and various functional exercises can be performed, such as straight line jump, Z-jump, figure 8 jump, etc. The ankle joint should be protected with ankle brace or bandage when playing sports within 3 months after the injury.
(2) Surgery: It is suitable for patients with obvious instability of the ankle joint. It is found that when both the anterior talofibular ligament and the heel-fibular ligament are ruptured, conservative treatment is satisfactory in about 58% of patients, while the satisfaction rate of surgical treatment is up to 89%. The torn ligament severed ends should be surgically sutured together; when the ligament is avulsed from the stop and direct suturing is difficult, ligament stop reconstruction should be performed. When intra-articular osteochondral injury is suspected, arthroscopic exploration should be performed to remove the joint free body. After 3 weeks of postoperative plaster immobilization, rehabilitation training such as joint mobility, muscle strength and proprioception should be started early.
(2) Acute injury of the medial collateral ligament (deltoid ligament)
Triangular ligament injuries account for less than 5% of ankle sprains and usually coexist with other injuries.
1. Mechanism of injury: valgus or anterior rotation injury is the mechanism of injury.
2.Injury pathology: simple deltoid ligament injury is rare, and the injury is usually mild. Severe deltoid ligament injury is often accompanied by distal or proximal fibula fracture, lower tibiofibular separation and complete rupture of the anterior and posterior ligaments of the lower tibiofibula.
3.Diagnosis and differential diagnosis.
(1) Symptoms: swelling and pain of the soft tissues on the inside of the ankle joint, with ecchymosis in severe cases, accompanied by different degrees of activity restriction.
(2) Physical signs.
(1) Pressure pain: the most obvious pressure pain is below the tip of the medial ankle.
(2) Foot rotation test: Repeat the injury action and rotate the foot passively forward, and pain will appear at the corresponding injury site medially.
③Front drawer test and valgus stress test: the examination method is the same as the lateral collateral ligament rupture, the difference is that the stress test does valgus action when examining the medial collateral ligament.
(3) Auxiliary examinations include ankle X-ray, arthrography and MRI
(1) X-ray: including anterior-posterior, lateral, ankle point and stress position of the ankle joint. Note whether the talus is displaced. If the medial joint gap in the ankle point position is greater than 4 mm, a rupture of the deltoid ligament can be diagnosed. Radiography in the valgus stress position can measure the tilt angle of the talus, and if the tilt angle is greater than 10 degrees, ligament rupture can be diagnosed.
②Arthrography: When the deltoid ligament is completely ruptured, the ankle joint contrast agent will spill out of the joint. However, this test is invasive and does not need to be performed routinely.
③MRI: A 10-degree axial film of the dorsal extension of the ankle joint shows the four parts that make up the deltoid ligament, while the coronal view shows the superficial and deep layers of the deltoid ligament. The coronal triangular ligament is fan-shaped and shows heterogeneous signal due to the presence of fatty tissue between the fibrous bundles. In acute injury, it shows lamellar high signal in the ligament with low signal, loss of ligament, interruption of continuity, surrounding soft tissue edema, and joint cavity effusion.
(4) Differential diagnosis: pay attention to the combination of external ankle fracture, posterior talus fracture, lower tibiofibular separation and other injuries.
4.Treatment
(1) Conservative treatment: Simple medial collateral ligament injury is very rare, usually the injury is mild and only requires conservative treatment. Including rest, ice, compression bandages and elevation of the affected limb. In case of combined lower tibiofibular separation, if the ankle point returns to normal after closed repositioning and there is no elastic resistance, the ankle joint can be maintained in a mild plantarflexion and inversion position for 3 weeks in a cast. The cast can then be replaced with a neutral position for another 3 weeks, during which time partial weight bearing is possible. X-ray review is required throughout the procedure to ensure that there is no separation of the lower tibiofibular union.
(2) Surgical treatment: If the lower tibiofibular separation is combined and closed reduction fails, surgical treatment is required. Surgery includes repositioning the lower tibiofibular separation, fixing the lower tibiofibular joint with transverse screws, and suturing the torn deltoid ligament. In a small number of patients, surgery is also needed for instability after a simple rupture of the deltoid ligament.
Chronic instability of the ankle joint
Chronic instability of the ankle joint is mainly caused by old damage to the ligaments and should be treated conservatively first if symptoms are present.
(I) Chronic instability of the lateral ankle joint
1. Etiology: caused by old injury to the anterior talofibular ligament and the heel-fibular ligament.
2. Diagnosis and differential diagnosis.
(1) Symptoms: instability of the ankle joint, easy to repeatedly inversion or post-rotation sprain, especially on uneven ground or when playing sports.
(2) Physical signs.
(2) Signs: ① Pressure pain: pain and pressure pain are not obvious in the chronic phase.
(2) Drawer test and inversion test: compared with the opposite side, the ankle joint is lax and the mobility is significantly increased.
(3) Auxiliary examination: including ankle X-ray and MRI.
(1) X-ray: including anterior-posterior, lateral, ankle point and stress position of the ankle joint. The degree of laxity of the ankle joint is judged according to the stress position. In case of combined ankle osteoarthropathy, hyperplastic bone can be seen on X-ray.
②MRI: The chronic phase of ligament injury is manifested by ligament loss, thinning, laxity and bending or thickening due to scar proliferation and hematoma mechanization. At the same time, it can be clarified whether the combination of articular cartilage damage, impingement syndrome.
(4) Differential diagnosis: pay attention to differentiate from osteochondral injury of the talus and recurrent dislocation of the peroneal tendon.
3.Treatment.
(1) Conservative treatment: mainly muscle strength exercises, such as heel lift training, inversion and valgus resistance exercises, etc. Athletes can use rubber plaster support band to strengthen the stability of the joint, and carry out normal training and competition.
(2) Surgical treatment: If conservative treatment fails, surgical treatment should be considered. After surgery, the ankle joint should be fixed in neutral position for 3 weeks in a non-weight-bearing cast, and then replaced by a walking cast for 5 weeks. There are various surgical methods, which can be divided into 3 major categories.
(1) Ligament shortening: the anterior talofibular ligament and the heel-fibular ligament are cut at 2 mm from the outer ankle stop, then overlapping shortening sutures are placed and the extensor support band is sutured to the outer ankle to reinforce the repair ligament.
(2) Anterior superior displacement of the ligament stop: expose the attachment point of the anterior talofibular ligament and the heel-fibular ligament in the outer ankle, cut off the attachment point of the ligament along with the periosteum, separate the anterior talofibular ligament and the heel-fibular ligament flap distally, drill holes on the posterior and proximal sides of the original stop of the ligament, pull the anterior talofibular ligament to the posterior side and the heel-fibular ligament to the proximal side for fixation.
(3) Tendon graft to reconstruct the ligament: the short peroneal tendon and metatarsal tendon can be used to reconstruct the lateral collateral ligament.
(2) Chronic instability of the medial ankle joint
1. Etiology: caused by old injury to the deltoid ligament, which is less common.
2. Diagnosis and differential diagnosis.
(1) Symptoms: instability of the ankle joint, easily sprained by repeated external rotation, especially on uneven ground or when playing sports.
(2) Physical signs.
(2) Signs: ① Pressure pain: pain and pressure pain are not obvious in the chronic phase.
(2) Drawer test and inversion test: compared with the opposite side, the mobility of the ankle joint is significantly increased.
(3) Auxiliary examination: including ankle X-ray and MRI.
(1) X-ray: conventional X-ray examination is mostly normal, and there may be avulsion fracture at the attachment of the triangular ligament at the tip of the inner ankle. External rotation stress X-ray can exclude the occult lower tibiofibular joint separation. External rotation stress position can diagnose medial ankle instability if the talus tilt angle is found to be greater than 10 degrees.
②MRI: The chronic phase of ligament injury is manifested by ligament loss, thinning, laxity and bending or thickening due to scar proliferation and hematoma mechanization. At the same time, it can be clarified whether the combination of articular cartilage damage, impingement syndrome.
(4) Differential diagnosis: Simple deltoid ligament injury is very rare. Among 110 cases of medial deltoid ligament injury in the ankle reported by Staples, only 2 cases were simple deltoid ligament injury. Note whether the combination of old lower tibiofibular joint separation or misaligned healed fibular fracture.
3.Treatment
(1) conservative treatment: muscle strength exercises, including posterior tibial muscle, anterior tibial muscle, flexor [longus, etc. Athletes can use rubber plaster support band to strengthen joint stability, normal training and competition.
(2) Surgical treatment: conservative treatment failure should be considered surgical treatment. The DuVries method is to cut the deltoid ligament crucially and then overlap the sutures to tighten the ligament, which is simple and effective. The principle of plaster fixation is the same as that of posterolateral chronic instability.