Knee positioning systems for X-ray environment: a literature review

Abstract

The knee is one of the most stressed joints of the human body, being susceptible to ligament injuries and degenerative diseases. Due to the rising incidence of knee pathologies, the number of knee X-rays acquired is also increasing. Such X-rays are obtained for the diagnosis of knee injuries, the evaluation of the knee before and after surgery, and the monitoring of the knee joint’s stability. These types of diagnosis and monitoring of the knee usually involve radiography under physical stress. This widely used medical tool provides a more objective analysis of the measurement of the knee laxity than a physical examination does, involving knee stress tests, such as valgus, varus, and Lachman. Despite being an improvement to physical examination regarding the physician’s bias, stress radiography is still performed manually in a lot of healthcare facilities. To avoid exposing the physician to radiation and to decrease the number of X-ray images rejected due to inadequate positioning of the patient or the presence of artefacts, positioning systems for stress radiography of the knee have been developed. This review analyses knee positioning systems for X-ray environment, concluding that they have improved the objectivity and reproducibility during stress radiographs, but have failed to either be radiolucent or versatile with a simple ergonomic set-up.

Functional Imaging of the Knee—A Comprehensive Review

“…2,5 Varus stress radiographs assess the lateral compartment ligaments which primarily consist of the fibular collateral ligament and posterolateral corner. 2,5 Valgus stress radiographs assess the medial compartment ligaments which primarily consist of the medial collateral ligament and posterior oblique ligament (Figure 1). 2,5 Lachman stress radiographs assess anterior tibial translation to test the anterior cruciate ligament.…”

“…2,5 Valgus stress radiographs assess the medial compartment ligaments which primarily consist of the medial collateral ligament and posterior oblique ligament (Figure 1). 2,5 Lachman stress radiographs assess anterior tibial translation to test the anterior cruciate ligament. 2,5 Posterior (kneeling) stress radiographs evaluate posterior tibial translation chiefly assessing the posterior cruciate ligament while the patient is kneeling on a This article is protected by copyright.…”

“…1 The standard anterior/posterior and lateral radiographs are typically screening tools in the setting of a traumatic or atraumatic process, such as identifying indirect signs of anterior cruciate ligament (ACL) injury or evaluating osteoarthritis (OA). 2 However, further imaging with stress radiographs can provide more information regarding knee instability and laxity. In the acute setting, stress radiography can be utilized for assessing ligamentous injuries, which can aid in preoperative decision-making and postoperative evaluation.…”

“…2,3 Varus, valgus, and Lachman stress radiographs position the patient in supine and knee flexed 20 to 30 degrees with specific pressure applied. 2,3 Varus stress radiographs assess the lateral compartment ligaments which primarily consist of the fibular collateral ligament and posterolateral corner. 2,3 Valgus stress radiographs assess the medial compartment ligaments which primarily consist of the medial collateral ligament and posterior oblique ligament (►Fig.…”

“…2,3 Lachman stress radiographs assess anterior tibial translation to test the ACL. 2,3 Posterior (kneeling) stress radiographs evaluate posterior tibial translation chiefly assessing the posterior cruciate ligament while the patient is kneeling on a platform at 90-degree angle. Beyond stress radiographs, additional radiographic imaging methods include fluoroscopy and dynamic stereoradiography (DSR).…”