4.1 The treatment of acute ankle ligament injury
Lateral ligament of the ankle joint mainly consist of three ligaments: ATFL, CFL and posterior talofibular ligament (PTFL). As we know, the PTFL injury is extremely rare. Therefore, the injury of the lateral ankle ligament is usually referred to as ATFL and/or CFL injury. According to Chorley's classification criteria, the injury of the lateral ligament complex of the ankle without fracture can be categorized into three degree: Grade I injury refers to the slight strain of ligament and the tear of ligament fiber, but the joint is stable; Grade II injury refers to partial ligament rupture, local swelling and pain, regional loss of ankle function with mild or moderate instability; Grade III injury refers to total ligament rupture, obvious local swelling and tenderness, subcutaneous ecchymosis, joint relaxation and instability. In short, the I and II degree of injuries mainly indicate ligament contusion and partial tearing. Conservative treatment can live up to great clinical expectation, and the recovery of function after treatment is also satisfied. Whereas the III degree ankle joint injury implies the complete tear of ATFL and CFL, which can cause instability and functional decline of ankle joint. To make the matters worse, there is some controversy in its treatment.
By means of local injection of hyaluronic acid, strict ankle plaster fixation for 6 weeks and individualized rehabilitation treatment for 3weeks, Řezaninova et al treated 17 young athletes at III degree lateral ligament injury and followed them up for one year. As a result, none of ankle instability occurred. In contrast, Suhr et al followed up 416 patients with ankle sprain who received conservative treatment, 15.9% (66 cases) requiring re-operation. Kerkhoffs et al retrospectively analyzed the results of the conservative treatment and operative treatment for 2562 male adult patients with injury of lateral ankle ligament complex. The result showed that the effective rate of emergency operative treatment was 90%~95%, which was superior to conservative treatment in terms of the activity of daily living, preventing chronic pain, recurrent sprains and the subjective or functional ankle instability. Contrary to research results above, the operative treatment in acute stage is not recommended for simple Ⅲ degree ankle ligament injury yet according to the current relevant guidelines.
At present, there is no relevant literature to report the incidence of ankle joint instability after fixing the fracture alone for patients with ankle fracture combined with lateral ligament injury. However, on the basis of the injury mechanism of lateral ligament of ankle joint: If the foot is suddenly on adduction or entropion when the ankle joint in the plantar-flexion position, strong tension on the lateral ligament of the ankle joint may lead to ligament strain, rupture even avulsion fracture. In consideration of the instability caused by the rupture of ankle ligaments, if the force is not removed right away, there will be collision between the bone and the bone, resulting in the fracture of ankle. Consequently, in this situation the force of injury is significantly greater than that of ankle ligament injury alone, the degree of injury is more serious and the range is more extensive. Once the patients, who have underwent ankle fracture caused by trauma, suffer from chronic instability of ankle joint after operation, the incidence of traumatic arthritis and chronic cartilage injury are more likely to be higher, and the time of complications occurring is earlier. Therefore, we advocate the simultaneous repair of ligaments rupture and fracture fixation for patients who with ankle fracture complicated with III degree ankle ligament injury.
4.2 The diagnosis of Acute Ⅲ Degree Injury of Lateral Ankle Ligament complex
In this study, all the patients had fresh fracture combined with lateral ligament complex injury of ankle joint, so it was difficult to carry out drawer test, talus tilt test and stress position test for detecting ankle joint stability. And even if MRI was performed, it was often difficult to distinguish whether ligament was completely ruptured due to the factors such as bleeding and edema in the acute state. Opposed to MRI, by conducting Ultrasound for patients with acute ligament injury, not only could the edema and coarsening of ligament, abnormal signal in ligament (low signal, high signal, blood flow signal, etc.), ligament relaxation after rupture and avulsion fracture accompanying with Ligament insertion rupture, be obviously observed, but also Ultrasound has the advantages of dynamic observation and high specificity.As a consequence, it can be widely used in preoperative diagnosis of acute and chronic ankle injuries. So in recent years, more and more scholars have adopted Ultrasound for the diagnosis of ankle ligament injury. For this study of cases, we presented Ultrasound as a routinely performed examination before surgery, the imaging results of which were basically consistent with those during operation.
Secondly, in order to further confirm the ligament injury and decide whether there is need to repair the lateral ligament, the stress position of the patients in this study was examined by intraoperative fluoroscopy after anesthesia or intraoperative fixation of the fracture. And for the reason that the anterior drawer test and talus tilt test differed greatly for individual, the stress image of ankle joint on the healthy side compared with that of the lesion side should be as the judgement standard. If one of the following conditions occurred, it should be judged that the lateral instability of the ankle joint existed and the lateral ligament required repairing: Inclination of talus more than 10 degrees or anterior displacement of talus more than 8 mm under stress radio-graphs; Compared to the opposite side, inclination of talus more than 5 degrees or anterior displacement of talus more than 5 mm.
4.3 operative indications and advantages of one-stage repair of ankle fracture combined with lateral ligament injury
Due to the conservative treatment for Ⅲ degree of Lateral ankle ligament damage alone having a good effect on about 85% of patients, the operative indications should be strictly controlled for the one-stage repair of ankle fracture combined with lateral ligament injury. But there is absence of relevant literature for reference, the following operative indications are proposed:
①Patients for Grade III injury of lateral ligament with foot and ankle fracture requiring operation.
If combined with intra-articular fracture of foot and ankle, the repair of the lateral ligament can provide a stable ankle joint, which is beneficial for reducing or delaying the incidence of postoperative traumatic arthritis; If accompanied with internal ankle fracture, it is often caused by the collision of internal talus, which is easy to cause damage to talus cartilage. After the repair of lateral ligament, stable ankle joint is conducive to the self-repair of mild cartilage injury and the prevention of subsequent cartilage injury[14, 15]. If attached with fracture of talus and fibula, the repair of lateral ligament injury can be completed within the same approach, so the operative trauma is limited.
② Patients for Ⅲ degree injury of the lateral ligaments associated with Avulsion fracture
Reiner et al counted 47 patients with reconstruction of lateral ankle ligament, of whom 66% (31cases) had avulsion fracture of ankle joint or fibular. Avulsion fracture indirectly indicates the degree of ligament injury, and the avulsion of ligament insertion also increases the length of ligament, raising the possibility of the instability of ankle joint. Moreover, if the free bone fragment can’t be absorbed, it would be free in the joint, which may cause collision and damage to the articular cartilage, so the removal of free fragment and repair of the lateral ligaments can relieve pain and reduce the incidence of chronic instability.
③ Ankle and foot fracture in patients who with chronic instability of the lateral ankle in the past
In this part of patients, operative indications are available for them before flesh fracture occurs, hence during the surgery after anesthesia, the fracture fixation and ligament repair could be performed at the same time, which reduces the risk of re-operation and the medical cost, and also helps to improve the activity of daily living after injury.
④Patients for Simultaneous Ⅲ degree injury of ATFL and CFL
It was reported that the rotation of medial ankle joint increased 3 times after the ATFL rupture. What’s more, the rotation will increase by 4 times if the ATFL and CFL are all broken. It is easy to cause damage to the medial triangle ligament and aggravate the instability of the ankle joint. To avoid the chronic injury of the triangular ligament, the lateral ligament repair should be promoted.