This injury is considered equivalent to adult ACL tears, as children and adolescents have a greater propensity to suffer acute bone injury from ACL avulsion of the tibial spines rather than ligamentous tear of the ACL as compared to adults. Tibial spine fractures most often occur in skeletally immature knees. 7 The primary emphasis is placed on surgical intervention for the underlying knee internal derangement. Although the injury is subtle in appearance on radiographs, magnetic resonance imaging (MRI) demonstrates the strong association with ACL tear to greater detail). On radiographs, the Segond fracture appears as a small, avulsed bone fragment from the lateral tibial plateau (Figure 1). Patients commonly present with acute knee pain. 8 The typical mechanism involves excessive internal rotation and varus stress, which cause a focal avulsion of bone from the lateral tibial plateau, commonly sustained as a sports-related injury. The Segond fracture is important to recognize due to its strong association with anterior cruciate ligament (ACL) and meniscal tears. We also discuss incidental signs of degenerative joint disease and a developmental anomaly on knee radiographs that mimics worrisome pathology, in order to allow definitive diagnosis and to bestow confidence that no further work up is required. In this article we describe worrisome imaging signs on knee radiographs to inform radiologists and radiologists-in-training how to identify a select group of difficult-to-diagnose traumatic pathologies and when to recommend additional imaging or clinical work up. 4 Other common options in a knee radiograph series include weight-bearing, patellar tangential, oblique, and cross-table lateral views. 3-5 A variety of knee radiography protocols exist, but every study should at minimum contain frontal (anteroposterior or posteroanterior) and lateral views.
Knee radiography is one of the most common musculoskeletal studies interpreted by radiologists in daily clinical practice and is the standard of care for initial imaging of acute or chronic knee pathology. Most diagnostic errors by radiologists in clinical practice involve musculoskeletal findings on radiographs, and missed fractures represent more than 90% of malpractice claims. The second part will appear in the March/April 2023 issue of Applied Radiology. SA-CME credits are available for this article here.Įditor’s note: This is the first part of a two-part series.