Case Report of a Traumatic Arthrotomy of the Knee Diagnosed by Ultrasound

In this case report we describe evaluating a patient for a traumatic knee arthrotomy using ultrasound in a resource-limited medical clinic at the base of a ski area. A 23-y-old female presented with a laceration superior to the patella of the left leg. On examination, the wound tracked deep, and providers had concern for traumatic arthrotomy. Lacerations around the knee have the highest risk for traumatic arthrotomy of any joint. This risk is due to the joint capsule of the knee extending up to 12 cm proximally from the joint line of the knee, making suprapatellar lacerations a risk. Although surgical evaluation is the gold standard for diagnosing a traumatic arthrotomy, computed tomography scan has been shown to be more sensitive than the saline-load test for identifying open traumatic arthrotomies. However, computed tomography scan was not available at the ski area clinic, and the authors have found the saline-load test to be extremely painful for patients. In this case, a novel technique using ultrasound to visualize a sterile cotton swab being inserted into the wound until it contacted the knee's joint line successfully identified a traumatic arthrotomy in a proximal knee laceration. The patient was transferred to a trauma center, where she had a surgical washout of her left knee joint. In conclusion, providers should be aware of the risk of traumatic arthrotomy in wounds that are proximal/superior to the patella. In this case, an ultrasound was used to confirm that the wound entered the proximal knee joint.