Assessment of Laxity in Multiligamentous Knee Injuries Using Stress Radiographs: A Simple Technique for a Busy Clinic

Darius L Lameire; Ajay Shah; Lawrence Wengle; Ryan M Khan; Daniel B Whelan

doi:10.1177/26350254251378514

Assessment of Laxity in Multiligamentous Knee Injuries Using Stress Radiographs: A Simple Technique for a Busy Clinic

Video J Sports Med. 2026 Mar 11;6(2):26350254251378514. doi: 10.1177/26350254251378514. eCollection 2026 Mar-Apr.

Authors

Darius L Lameire¹, Ajay Shah¹, Lawrence Wengle¹, Ryan M Khan², Daniel B Whelan^{1

2}

Affiliations

¹ Division of Orthopaedic Surgery, University of Toronto Faculty of Medicine, Toronto, Ontario, Canada.
² Division of Orthopaedic Surgery, Department of Surgery, Saint Michael's Hospital, Toronto, Ontario, Canada.

Abstract

Background: Multiligamentous knee injuries are complex, with highly individualized treatment plans based on patient and injury-specific factors. Stress radiographs are an important tool for objectively quantifying knee laxity; however, they are often not formally taught during clinical training.

Purpose: To provide a reproducible method for obtaining stress radiographs.

Indications: Stress knee radiographs are used in the setting of acute and chronic knee ligamentous and soft tissue injury.

Technique description: Coronal laxity: Knees are flexed at 20°, the x-ray beam is tilted 20° cephalad, and aligned with the inferior pole of the patella. Apply a valgus force with slight external rotation to the knee to test the medial collateral ligament (MCL). Perform on the contralateral knee. Use a varus force to test the lateral collateral ligament (LCL) and the posterolateral corner. Measure the joint space width with the LaPrade method. Sagittal laxity: Position the patient supine and flex the knee to 80°. The patient holds the cassette parallel to the x-ray beam, which is at the foot of the bed. Allow the tibia to sag without support, and compare the side-to-side difference on the bilateral radiograph.

Results: The case in this video shows a side-to-side difference, suggesting a grade 3 MCL, LCL, and partial posterior cruciate ligament injury.

Discussion/conclusion: Stress radiographs support accurate diagnosis of complex knee injuries and provide an objective measure of knee stability. These techniques can be performed in an ambulatory clinic setting and are cost-effective, efficient, and support clinical decision-making in the treatment of complex knee injuries.

Patient consent disclosure statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Keywords: knee ligament injury; physical examination techniques; stress radiographs; valgus; varus.