Traumatic arthrotomy

Saline load test has classically been the diagnostic test of choice when traumatic arthrotomy is suspected. A downside to the saline load test is that it requires violation of the joint with a needle, both painful and potentially infection-introducing, and the saline load is uncomfortable for the patient. The volume required for the saline load test is typically 150-200mL to achieve 95-99% sensitivity in adults. The volume needed for children is less clear, although one study by Haller et al found a volume of 47mL to be 90% sensitive in a sample of 5-18 year olds. In 2013, Konda et al found that CT performed better than the saline load test in diagnosing intraarticular air, an indication of traumatic arthrotomy of the knee. Some authors (Noble et al) have raised the possibility of false positives with use of CT to diagnose traumatic arthrotomy due to “vacuum phenomenon” whereby gas is pulled out of solution in association with closed tibial fracture.