Ankle impingement is a common condition that usually occurs due to repeated ankle sprain or microtrauma. Ankle inversion sprain injuries accounts for almost 10% of all cases visiting emergency departments. Majority of ankle injuries resolve quickly but according to Gerber et al, close to 40% of patients have residual symptoms that can last up to 6 months. Synovial hypertrophy and impingement can be happening as a result of injuries.
This can happen anteriorly or posteriorly. Anterior ankle impingement can further devided into anterolateral and anteriomedial impingements. The same rule can be applied for the posterior impingements. Patients usually complain of lack of range of motion (mostly ankle dorsiflexion), vague pain, and ankle instability. MRI does not seem to be reliable imaging modality to look at the soft tissue structures but ankle arthroscopic debridement is recommended.
They did three different experiments with A) plantar flexion of the left ankle with thumb pressure over the anterolateral aspect B) dorsiflexion of the ankle with no thumb pressure and C) combination of the two maneuvers.
They used a frozen anatomical piece for the meniscoid tissue of a knee to stimulate the synovial impingement. It was placed between the tibiotalar joint. The only maneuver that could cause the impingement was when pressure with thumb was applied to the anterior aspect of the gutter with bringing the ankle to dorsiflexion. All participants who had ankle instability were excluded from the study. There were 73 participants in this study who went through arthroscopic examination. They were 41 out of 73 who showed positive impingement sign before going through arthroscopy. 37 out of 41 patients happened to have synovial hypertrophy in the lateral gutter. The ankle impingement sign had a sensitivity of 94.8% and a specificity of 88%. Other patients had other lesions such as chondral lesions, anterior osteophytes, and intra-articular adhesions.
Another study I looked at showed 83% sensitivity in diagnosing anterolateral soft tissue impingement of the ankle. Anterolateral soft tissue impingement could happen as a result of synovitis and fibrosis. Using MRI for chronic ankle sprain; however, is still controversial.
1:Bendall, S, P. Synovial impingement in the ankle. A new physical sign. The Journal of Bone and Joint Surgery. British Volume [2003, 85(3):330-3]
2.Ferkel R, Tyorkin M, Applegate G, Heinen G. MRI Evaluation of Anterolateral Soft Tissue Impingement of the Ankle. Foot & Ankle International. 2010;31(8):655-661.