Ankle impingement was first described by Morris in 1942, when it was referred to as the athlete’s ankle, and later defined by McMurray as the soccer player’s ankle. Nowadays, anterior ankle impingement syndrome describes the chronic pain in the ankle joint and the possible accompanying limitation of ankle motion that occurs in the presence of impingement of anatomical structures within and around the ankle joint. This article focuses on the common causes of anterior ankle impingement, clinical diagnostic evaluation, treatment modalities and outcomes.
Anterolateral ankle impingement
In the United States, more than 23,000 inversion ankle sprains occur daily, mostly in athletes. Roughly 20% of patients will have residual symptoms and chronic ankle pain. Studies show that 50 percent of basketball players who experience ankle sprains have residual symptoms and 15 percent will have an impact on their future athletic performance. Approximately 3% of ankle sprains result in anterolateral ankle impingement. Some scholars believe that the term chronic ankle sprain should be changed to anterolateral ankle impingement. The three most common soft tissue lesions that cause anterolateral impingement are meniscal-like lesions, synovitis, and distal anterior inferior tibiofibular ligament impingement.
Meniscus-like lesions
A soft tissue mass of hyaline-like tissue within the patient’s joint is defined as a meniscus-like lesion due to its resemblance to a torn meniscus of the knee and is listed as the cause of anterolateral impingement.
Synovitis
Synovitis may also occur after an inversion sprain of the ankle joint. The sprain may damage the anterior talofibular ligament, anterior inferior tibiofibular ligament, or heel-fibular ligament without significant ankle instability. Inappropriate treatment and rehabilitation can lead to poor healing, prompting repetitive joint motion leading to inflammation of the ligamentous stops. After a period of time, continued motion thickens the synovial membrane, leading to lateral groove impingement and chronic pain on the lateral aspect of the ankle. Minor capsular tears form intra-articular hematomas, leading to hemorrhagic synovitis. The hematoma is eventually absorbed by the synovium, leading to synovitis.
Distal bundle of the anterior inferior tibiofibular ligament
Bassett and colleagues identified another cause of impingement that occurs after an inversion sprain of the ankle, which they described at the time as the distal bundle of the anterior inferior tibiofibular ligament. The presence of the distal bundle of the anterior inferior tibiofibular ligament ranged from 21% to 92%, and this variation may be due to the different perceptions of the distal bundle by different scholars. The presence of the distal fascicle is normal, but it becomes pathogenic when there is an alteration in the mechanical activity of the ankle joint.
Anterolateral ankle impingement
The most common cause of anterolateral ankle impingement is a bony lesion that presents as pain on the anteromedial aspect of the ankle. A small number of cases are also due to soft tissue and occupying lesions within the ankle joint. The main discussion here is on bony lesions. The tibial talar osteophyte that forms on the anterior aspect of the ankle joint is a common cause of chronic pain in the ankle joint.
Clinical presentation
Patients typically present with persistent ankle pain with a history of recent trauma. The patient is usually a young athlete who has had an inversion-type ankle sprain. Patients can have a single severe trauma or a recurrent ankle sprain. The patient’s pain worsens after prolonged walking or sports and may also describe an intra-articular popping and strangulation. Passive dorsiflexion and valgus activities can induce pain. A popping sound may also be heard during ankle motion. Other causes of anterolateral ankle pain must be excluded clinically, such as talar cartilage injury, peroneal tendonitis or subluxation, tarsal coalition and subtalar joint dysfunction.
X-ray examination
Plain radiographs can be used to rule out fractures, widening of the ankle cavity gap or arthritic changes. Stress radiographs can be used to exclude ligamentous laxity. Accurate preoperative examination and localization of the bony tuberosity is essential when the patient is suspected of having anterolateral impingement of the ankle. Standard lateral radiographs are not very accurate in detecting anteromedial impingement, detecting only 40% of tibial impingements and 32% of talar impingements. Oblique radiographs (45/30 anteromedial impingement [AMI] position) are required. In combination with 45/30 AMI, the sensitivity of tibial and talar osteochondrosis was increased to 85% and 73%.
Nuclear magnetic resonance examination
X-rays are important in detecting bony lesions. MRI is the most useful modality to evaluate soft tissue impingement and to rule out other ankle pathologies such as talar cartilage injury, peroneal tendonitis, tarsal coalition, tarsal sinus syndrome, etc.
CT examinations
CT examinations are useful in detecting bony and cartilaginous lesions. Three-dimensional CT examinations are used for preoperative design to accurately locate the tibial talar styloid, which can improve the results of arthroscopic surgery.
Treatment
Conservative treatment
Conservative treatment includes rest from weight bearing, non-steroidal anti-inflammatory drugs (e.g., fotarolimus), ice, steroid injections, bracing, and physical therapy. However, the results of conservative treatment are usually unsatisfactory. Patients who have failed to receive regular conservative treatment for 3-6 months may consider surgery.
Surgical treatment
The main treatment is ankle arthroscopic surgery. Soft tissue and bony lesions in the ankle joint are examined under arthroscopy and cleaned up at the same time.
This is an arthroscopic image of the ankle joint. Figure 1 is a normal presentation with a very smooth intra-articular joint. Figure 2 is a presentation with ankle impingement, and you can see the scar tissue jamming within the joint that has grown.
Clinical results
The results of arthroscopic surgery in patients who have failed conservative treatment are satisfactory, with excellent rates ranging from 75% to 90%.Martin first reported the follow-up results of the application of arthroscopic treatment for soft tissue impingement in the anterior ankle, and Ferkel et al. retrospectively studied the results of 31 patients over 2 years of follow-up, with an excellent rate of 85%.Meislin et al. treated 29 patients with synovial impingement Meislin et al. treated 29 patients with synovial impingement and the excellent rate at 25 months follow-up was 90%. Urguden et al. reported the results of 41 patients at a mean follow-up of 84 months, evaluated using the AOFAS (American Orthopaedic Foot and Ankle Surgery Society) scoring system. The outcome was excellent in 37 patients with a mean AOFAS score of 89.6.
Conclusion
Anterior impingement of the ankle joint is a common and indeed underestimated ankle disorder in clinical practice, and satisfactory clinical outcomes can be achieved by increasing awareness, improving diagnosis, and applying minimally invasive arthroscopic surgical treatment.