Abstract

Background: Bone contusions are often identified at magnetic resonance imaging (MRI) in the acutely injured knee. Contusions of both surfaces of the joint are known as kissing contusions.

Objective: To determine the frequency, type, and distribution of kissing contusions occurring in association with injuries of the knee joint.

Methods: 255 MRI examinations in athletes with acutely injured knees (197 men; 58 women; mean age 24.2 years) were reviewed by two independent examiners; 219 MRIs were done within the first month after the injury and 36 within two to four months. None of the knees had been injured before. No fractures were present on x ray.

Results: Bone contusions were diagnosed in 71 cases (27.8%); 55 (22.5%) were identified as single contusions and 16 (6.3%) as kissing contusions. Eight of the kissing contusions were associated with anterior cruciate ligament tears, three with menisceal tears, four were isolated lesions, and one was delayed, following a menisceal tear. The 32 bone contusions (16 kissing contusions) were located as follows: lateral femoral condyle (n = 14; 8 type I, 6 type II); lateral tibial condyle (n = 9; 3 type I, 1 type II, 5 type III); medial tibial condyle (n = 7; 2 type I, 5 type III); medial femoral condyle (n = 2; both type I). The associated injuries were confirmed by arthroscopy in 12/16 patients.

Conclusions: Kissing contusion is a significant injury often associated with ligamentous or menisceal injuries. Type I lesions are most common on the lateral femoral condyle and type III on the lateral tibial condyle.