The symptoms of acute ATFL partial tear including pain, swelling, weakness, and range of motion limitation. Most of the patients can recover in a few weeks with conservative treatment. The inflammation stage takes the first 3 to 7 days which is the most uncomfortable. The painful disability at the first week has significant negative effects on working and quality of life. Steroid has a strong effect of anti-inflammation and it may improve the symptoms of injury at acute stage. Steroid injection for rotator cuff tendon rupture was proved to be safe and effective in short term to relieve pain in a prospective randomized study previously done by our team (10). However, in-vitro studies have shown steroids have necrosis-inducing effects on fibroblasts and tenocytes so that it may have a negative effect for tissue healing (11). Although steroid injection is very popular in clinical practice, it is still controversial for the injured tendons and ligaments. In the current study, we revealed steroid local injection can safely shorten the period of functional disability and relieve pain for acute ATFL partial tear.
Acute ankle ligament injuries are almost always managed by non-operative methods. Successful treatment can be achieved with individualized, aggressive and non-operative measures. A previous study revealed that patients who underwent acute surgical treatment took longer to return to work (16). Also, studies revealed that surgery was not helpful in reducing additional complications, costs and risks (17). Lateral ligament reconstruction of the ankle is indicated when conservative measures have failed to improve functional lateral ankle instability in order to prevent subsequent disorders such as osteochondral lesions of the talar dome and osteoarthritis of the ankle (18). The direct anatomic repair of lateral ligaments of the ankle, originally described by Broström (19), is popular and effective if indicated. The subsequent augmentation of the technique by additionally tightening the inferior extensor retinaculum has resulted in good outcomes in the literatures (20). However, the open technique requires at least a 4-cm-long incision with significant dissection and soft tissue debridement, and it sometimes causes superficial nerve injury (20). Recently, several authors have reported good results using an arthroscopy-assisted lateral ligament repair (21).
The clinical evidence of Platelet Rich Plasma (PRP) on soft tissue healing and repair is so far convincing. Case series have shown the beneficial effect on the partial thickness rotator cuff tear (22). PRP has been increasingly used for therapeutic applications in sports-related injuries, and is thought to stimulate tissue healing. Some studies supported PRP injection for ATFL injury as an alternative non-surgical treatment option with the potential to prevent the development of chronic ankle instability and post-traumatic ankle osteoarthritis (23). And the other study revealed the PRP group presented the highest reduction in pain and better functional scores than the control group at 8 weeks. However, the results of both groups were similar at the end of follow-up period (24). The role of PRP in ankle ATFL injury is still not clear. Therefore, further prospective randomized study for PRP injection is necessary.
ATFL injury has some associated injuries which cannot be evaluated by sonography, including osteochondroal lesion of talar dome and bone contusion. These associated injuries can only be diagnosed by MRI. In a study conducted on 261 ankle MRI scans of athletes who had acute ankle sprains, acute osteochondral lesions of the lateral talar dome were seen in 20 ankles (7.7%). And talar bone contusion risk increased more than three times for ATFL complete ruptures (25). If these associated injuries happen, the functional recovery and the healing process will be different from pure ligamentous injury. In the current study, we did not take associated osteochondral lesion and bone contusion into consideration because MRI was not performed in every patient.
The inclusion criteria of current study was ATFL acute injury less than 3 days. MRI was not the choice of current study because it cannot be available immediately. The definite diagnosis of ATFL injury is arthroscopy which is an invasive procedure and it cannot be apply for all the patients. Ultrasound can be a valuable technique for ATFL injury, but it is operator-dependent (7). Using sonography to evaluate ATFL can have some errors, including inter-observer and intra-observer variability. All sonographic examinations in this study were performed by the same experienced orthopedic surgeon to reduce the inter-observer variability, but intra-observer variability may still exist. In addition, the healing of ruptured ATFL was difficult to identified or compared by sonography (26). We performed sonography before injection, 6 weeks, and 12 weeks after injection. The only information we got from follow-up sonography were the decreasing inflammation and no deterioration of partial tear after injection. Besides, there is high interpatient variability in the structure of ATFL (27). Therefore, the results from sonography was difficult to be compared between groups.
There were some other limitations in the current study. Our sample size was too small, and the duration of follow-up was too short. Block randomization was used because the case number was not sufficient enough to perform the age and sex match distribution between groups. The period of follow-up was only 12 weeks in current study. However, ankle chronic instability after ligament injury was diagnosed after 12 weeks. Although we use ankle anterior drawer test to evaluate the stability for all patients at 12 weeks, the specificity and sensitivity of this physical examination is moderate. According to the literature, the specificity for the anterior drawer test assessed by arthrography ranged from 67.3 to 93.9 and the sensitivity ranged from 12.0 to 89.0 (28). Unlike acute ankle sprain, chronic ankle instability might require surgical intervention (29). Therefore, long term follow-up for ATFL partial tear treated by steroid local injection is necessary to evaluate its long term safety. A larger sample size is also required.