Evaluation of saline load test for simulated traumatic arthrotomies of the ankle

IntroductionA tool frequently used for evaluation of a traumatic arthrotomy is the saline load test. No information exists in the current literature guiding what baseline fluid infusion is required to reliably detect or diagnose a traumatic ankle arthrotomy. The purpose of this study was to provide a reliable benchmark when employing the saline load test for complex ankle soft-tissue wounds with suspected intra-articular involvement.Materials and methodsTwenty-one consecutive patients presenting for elective ankle arthroscopy underwent simulated saline load tests. After placement of an approximately 4-mm standard lateral portal, an 18-gauge needle was inserted into the anteromedial ankle joint and normal saline was injected until frank extravasation from the lateral arthrotomy was observed. The amount of saline required to diagnose a simulated traumatic arthrotomy was recorded.ResultsThe average amount of normal saline that resulted in extravasation was 10.3 cm3. In order to identify 90% and 95% of simulated ankle arthrotomies, 23 and 30 cm3 of saline were required, respectively. The average preoperative range of motion did not correlate with saline infusion requirements (r2 = 0.013368).ConclusionsBased on these results, a minimum infusion of 30 cm3 is recommended to identify 95% of traumatic arthrotomies approximately 4 mm in size. This value needs to be interpreted with the understanding that this study is limited by its inherently simulated nature. An infusion of 30 cm3 represents a relatively safe and reasonable standard to apply to any potential ankle injury in which joint violation remains in question.