The squeeze test is a physical examination technique used by clinicians to assess the stability of the lower leg, targeting the integrity of the tibiofibular syndesmosis. This joint complex, often called the high ankle, is frequently injured in athletes, leading to what is commonly termed a “high ankle sprain.” The test is a rapid, non-invasive method used to help differentiate a less severe lateral ankle sprain from a potentially more serious syndesmotic injury. A high ankle sprain injury often requires a different treatment approach and may involve a longer recovery period compared to a standard ankle sprain.
Anatomy of the High Ankle Sprain
The lower leg consists of two bones, the tibia and the fibula, which are held together along their length by a strong sheet of connective tissue called the interosseous membrane. The syndesmosis, or high ankle joint, is located at the end of these two bones, just above the ankle. This structure is stabilized by a network of ligaments that prevent the tibia and fibula from separating and twisting.
The primary ligaments involved in this stabilization are the anterior inferior tibiofibular ligament (AITFL) and the posterior inferior tibiofibular ligament (PITFL), along with the interosseous membrane itself. These ligaments work together to maintain a precise relationship between the tibia and fibula, which is essential for normal ankle mechanics. A high ankle sprain is defined as an injury to these specific ligaments, often occurring when the foot is forced into external rotation and dorsiflexion.
The stability provided by the syndesmosis is crucial because a healthy ankle joint depends on the tight fit of the talus bone between the two lower leg bones. When the syndesmotic ligaments are torn, the space between the tibia and fibula can widen, leading to joint instability.
How the Squeeze Test is Performed
The squeeze test, also known as the fibular compression test, is performed by the clinician to reproduce the patient’s pain away from the actual site of injury. The patient is typically positioned lying on their back with the injured leg extended and relaxed. This relaxed posture is important to ensure the muscles of the lower leg are not tensed, which could interfere with the test’s mechanism.
The examiner places their hands around the patient’s lower leg, usually at the mid-calf level, which is a significant distance above the ankle joint. The specific action involves compressing the tibia and fibula bones together by applying firm, inward pressure. This action is performed gradually, and the compression is applied transversely across the leg.
The mechanism of this test relies on the pressure transmitting force down the leg toward the ankle. When the clinician compresses the bones together in the mid-calf, the force causes a slight bowing of the bones, which in turn stresses the injured syndesmotic ligaments at the ankle. Applying the pressure at the mid-calf ensures that the pain felt is a result of the distant force on the syndesmosis, rather than direct pressure on a localized area of tenderness. For an accurate result, the clinician will often start the compression higher up the leg and gradually move their hands closer to the ankle to pinpoint the area of maximum tenderness.
Interpreting the Test Results
The result of the squeeze test is determined by the patient’s immediate pain response during the compression maneuver. A positive squeeze test occurs when the patient reports sharp, significant pain that is felt specifically at the distal ankle joint, where the syndesmotic ligaments are located. This pain response strongly suggests that the compression has stressed the high ankle joint, indicating a potential compromise of the stabilizing ligaments.
A negative test result, conversely, means the patient feels no pain or only mild, diffuse discomfort that does not localize to the syndesmosis. This finding suggests that the high ankle ligaments are likely intact and stable, pointing toward a more common lateral ankle sprain or another diagnosis. Clinicians also pay attention to the location of the pain, as pain felt higher up the leg during the test may correlate with a more extensive or severe syndesmotic injury.
While the squeeze test is a useful initial screening tool, its reliability has been debated. It has high specificity, meaning that if the test is positive, there is a very high likelihood that a syndesmotic injury is present. However, the test’s sensitivity is low, suggesting that it may fail to detect an injury in a notable percentage of cases, leading to a false negative result. A positive squeeze test is a strong indicator of instability, but a negative result does not completely rule out a high ankle sprain.
Other Diagnostic Tools for Ankle Injuries
The squeeze test is always used as part of a broader diagnostic examination because it may not be sufficient to definitively diagnose or grade a high ankle sprain. One common physical maneuver performed alongside the squeeze test is the External Rotation Test, sometimes called the Kleiger’s Test. This test involves stabilizing the lower leg and externally rotating the foot, with a positive result being pain at the syndesmosis, indicating a rotational instability of the joint.
Imaging Studies
Imaging studies are routinely necessary to confirm the diagnosis, rule out fractures, and evaluate the extent of soft tissue damage. Standard X-rays are usually the first step and are used to check for any associated bony injuries or a widening of the space between the tibia and fibula, which is a sign of significant syndesmotic instability. Weight-bearing X-rays are often preferred, as they can reveal instability that might not be visible when the patient is not standing.
For a more detailed assessment of the soft tissues, a Magnetic Resonance Imaging (MRI) scan is frequently utilized. MRI provides high-resolution images of the ligaments, including the AITFL and PITFL, and the interosseous membrane, allowing the clinician to visualize the degree of tear or rupture. Ultrasound is another tool that can be used to dynamically assess the syndesmotic ligaments, offering a real-time view of the joint’s stability during movement. These imaging techniques, combined with the physical examination findings, provide the comprehensive information required to establish an accurate diagnosis and create an appropriate treatment plan.