Kneeling Stress Radiography: A Forgotten Yet Dependable Tool for Postero-lateral Knee Instability.

Introduction: Diagnosing postero-lateral knee instability is a challenge from both clinical and radiologic perspective and can lead to significant morbidity if left untreated. Delayed diagnosis leads to a more demanding surgery and prolonged rehabilitation for the patient. Kneeling stress radiograph is a lost art but remains invaluable in the assessment of postero-lateral knee instability. Methods: This prospective observational study is aimed at re-exploring the undeniable utility of this forgotten tool in early diagnosis of posterolateral knee instability and identifying the mean posterior tibial translation distance (PTTD) and also assessing side to side difference (SSD) between the injured and the contralateral normal knee. Results: Total 27 patients were included in the study, with males being 4.4 times more commonly injured as compared to females. The most common mode of injury was motor vehicle accident (MVA). Out of 27 patients, 11 had isolated PCL (posterior cruciate ligament) injury while the rest had PLC (posterolateral corner) involvement. The mean SSD of PTTD was 8.79 mm in patient with isolated PCL. This was increased by 1.65 times (14.52 mm) in patients with co-existing PLC involvement. Conclusion: Stress radiography is an indelible tool and serves as an adjunct to MRI imaging. It is not a substitute for clinical assessment but assists in early diagnosis and management, facilitating surgical planning and furnishing objective evidence of PCL/PLC functionality which is not possible with any other imaging modality.