Background: Injuries to the posterolateral corner of the knee (PLC) can be difficult to diagnose and are often missed. The prone dial test can be difficult to perform in the acute setting and the supine dial test requires an assistant. Purpose: We present a simple single person seated dial test that can easily be performed in all patients with a suspected diagnosis of PLC injury. Study Design: Case Series. Method: The patient is seated on the edge of the examination couch with their knees flexed over the side and their calves pressed against the couch to reduce any posterior tibial subluxation. The patients’ knees are placed together ensuring the pelvis is square; the knees are at the same level, and the patellae are facing anteriorly. The patients place their hands against the side of their knees and hold their knees together in this position. The examiner then grasps the patient’s feet, approximates the medial malleoli and exerts a lateral rotational force at 30 and 90 degrees of knee flexion. Results: This test has 100% accuracy for diagnosing PLC injury in our institution. Conclusion: We present a sample to use alternative to traditional dial testing that does not require an assistant and also does not require the patient to be prone, thus limiting discomfort in the acute setting.
Injuries to the posterolateral corner of the knee (PLC) are often difficult to diagnose and so are often missed [1] -[3] . This can result in significant disability secondary to persistent instability and pain.
In PLC injury, the salient finding is that of increased tibial external rotation. This forms the basis for several clinical tests, most of which have fallen out of favour due to difficulty with interpretation and side-to-side comparison. Currently the dial testis most commonly used as this allows visual and tactile side-to-side comparison with the thigh-foot angle (TFA) or the patella-tubercle angle (PTA). The test can be done supine [4] or prone. Bae et al. have shown that the dial test correlates well with the degree of PLC injury [1] but it too can be difficult to perform accurately in a clinical setting [5] ; the prone technique may be difficult for patients with painful swollen knees, and itis difficult to visualise the PTA at 30 degrees of flexion [6] , and the standard supine technique requires an assistant to hold the thighs together [6] .
Therefore, a simple, reliable and reproducible test needs to be used by a single clinician to identify disruption of the posterolateral corner. We present a single-person, seated technique that can be performed as a user-friendly alternative to traditional tests.
2. Method
The patient is seated on the edge of the examination couch with their knees flexed over the side and their calves pressed against the couch to reduce any posterior tibial subluxation (Figures 1 and 2). The patients’ knees are placed together ensuring the pelvis is square, the knees are at the same level, and the patellae are facing anteriorly. The patient places their hands against the side of their knees and holds their knees together in this position (Figures 1 and 2). The examiner then grasps the patient’s feet, approximates the medial malleoli and exerts a lateral rotational force at 30 and 90 degrees of knee flexion (Figures 1-3).
3. Results
Between October 2009 and October 2012 this test has been used to identify 42 patients with PLC knee injury. MRI scan confirmed the presence of a PLC injury in all patients. All patients proceeded to PLC reconstruction
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