Justin M. Haller,James T. Beckmann,Ashley L. Kapron,Stephen K. Aoki

Background: The objective of this study was to quantify the load volume needed for a positive diagnosis of a traumatic arthrotomy in the pediatric knee with use of the saline solution load test (SLT).

Methods: From February 2013 to June 2014, eighty-seven pediatric patients who were undergoing elective knee arthroscopy were prospectively enrolled in this study. An SLT was performed in each patient using a 5-mm superolateral portal as the arthrotomy site, with injection of the saline solution into the lateral aspect of the knee. The 50th, 75th, 90th, and 95th percentiles of saline solution load volume required for a positive result were identified. Univariate linear regression was used to identify possible relationships between demographics (age, height, weight, and body mass index [BMI]) and load volume.

Results: Forty-one female and forty-six male patients with a mean age (and standard deviation) of 13.4 ± 3.0 years (range, five to eighteen years) and a mean BMI of 21.9 ± 5.0 kg/m2 (range, 12.9 to 36.2 kg/m2) were enrolled. The mean saline solution load volume was 28.9 ± 14.2 mL (range, 7.0 to 78 mL). The 50th, 75th, 90th, and 95th percentiles of saline solution load volume were 27, 37, 47, and 58 mL, respectively. The mean load volume did not differ significantly between male and female patients (28.8 ± 13.9 versus 29.0 ± 14.7 mL, respectively; p = 0.92). Load volume was significantly correlated with age, height, weight, and BMI.

Conclusions: On the basis of our findings, a saline solution load volume of 47 mL is required to detect 90% of superolateral traumatic arthrotomies of 5 mm in the pediatric knee with use of the SLT.