SCIENTIFIC ARTICLE Hyperextension injuries of the knee: do patterns of bone bruising predict soft tissue injury? A. M. Ali 1 & J. K. Pillai 2 & V. Gulati 3 & C. E. R. Gibbons 1 & B. J. Roberton 2 Received: 11 March 2017 /Revised: 31 July 2017 /Accepted: 2 August 2017 # ISS 2017 Abstract Objective To establish whether patterns of soft tissue injury fol- lowing knee hyperextension are associated with post-traumatic ‘bone bruise’ distribution. Materials and methods Patients with a knee MRI within one year of hyperextension injury were identified at our institution over a 7 year period. MRIs, plain radiographs and clinical details of these patients were reviewed. Results Twenty-five patients were identified (median time from injury to MRI = 24 days). The most common sites of bone bruising were the anteromedial tibial plateau (48%) and antero- lateral tibial plateau (44%). There were high rates of injury to the posterior capsule (52%), ACL (40%) and PCL (40%) but lower rates of injury to the menisci (20%), medial and lateral collateral ligaments (16%) and posterolateral corner (16%). Anterior tibial plateau oedema and rupture of the posterior cap- sule predicted cruciate ligament injury [OR = 10.5 (p = 0.02) and 24.0 (p = 0.001) respectively]. Whilst anterolateral tibial plateau oedema strongly predicted PCL injury [OR = 26.0, p = 0.003], ACL injury was associated with a variable pattern of bone bruising. Meniscal injury was unrelated to the extent or pattern of bone bruising. 5 out of 8 patients with a ‘double sulcus’ on the lateral radiograph had ACL injury. The presence of a double sulcus showed significant association with anteromedial kissing contusions (OR = 7.8, p = 0.03). Conclusions Following knee hyperextension, bone bruising patterns may be associated with cruciate ligament injury. Other structures are injured less frequently and have weaker associations with bone bruise distribution. The double sulcus sign is a radiographic marker that confers a high probability of ACL injury. Keywords Knee hyperextension . Bone bruising . MRI Introduction Hyperextension of the knee is a common injury in athletes that may result from a posteriorly directed force to the front of the knee or a non-contact mechanism such as landing on an ex- tended leg, forceful kicking or falling forward over a station- ary foot. These mechanisms frequently occur in sports includ- ing football, skiing, martial arts and gymnastics [1–3]. The literature on soft tissue injuries associated with knee hyperex- tension in vivo is sparse. ‘Bone bruises’ or ‘bone contusions’ refer to regions of oe- dema, bleeding and infarction of subcortical cancellous bone that has undergone compression fractures following trauma [4–6]. They are identified as regions of signal change on mag- netic resonance imaging (MRI), most sensitively using T2-weighted fat-saturation or short tau inversion recovery (STIR) sequence techniques [7]. Most of the literature sur- rounding bone bruising relates to the knee, and specific mech- anisms of injury appear to have characteristic bone bruising patterns that reflect the position of femoral impaction upon the tibia [8–10]. Bone bruising has important clinical implications. As it provides an explanation for pain, its recognition may reduce * A. M. Ali adamali@post.harvard.edu 1 Department of Orthopaedic Surgery, Chelsea and Westminster Hospital, London, UK 2 Department of Radiology, Chelsea and Westminster Hospital, London, UK 3 Department of Orthopaedic Surgery, Homerton University Hospital, London, UK Skeletal Radiol DOI 10.1007/s00256-017-2754-y