Bone Abstracts

Objectives: To make a prediction model for septic arthritis on the basis to analyze CRP versus CD64 on neutrophils (nCD64) as an adjunct parameter to Kocher’s criteria to differentiate septic arthritis from transient synovitis.

Methods: In this open ended prospective study, children (n=34) below 18 years of either gender (M=22/F=12) below 18 years presenting with acute, new onset, non – traumatic limp or joint pain were enrolled as cases and otherwise normal age-sex matched children as controls (n=35). Full clinical work up including Kocher’s criteria [Non weight-bearing; Temperature; Erythrocyte Sedimentation Rate (ESR) [Wintrobe method] and Total Leucocyte count (TLC) [Automated blood count] in addition to C-reactive protein (CRP) [CRP Turbilatex K LABKIT] and CD64 count on neutrophils (nCD64) [Fluorescence-activated cell sorting (FACS)] were done as per standard protocols and were analysed. Blood sample (2 ml) in plain/EDTA viol was collected at forenoon for lab work. High resolution sonography of joint was done to confirm presence or absence of joint effusion (if no effusion, excluded). Arthrocentesis done as per standard protocol under aseptic technique in effusion positive cases. The cases were divided into septic arthritis (polymorph>50 000 cells/mm³) and transient synovitis (polymorph<50,000 cells/mm³).

Results: We analyses 35 cases [septic arthritis (n=18), transient synovitis (n=13)] and controls (n=35). No statistically significant differences were found between demographics of cases and controls. Statistically significant differences were found in parameters like temperature, ESR, CRP, TLC and nCD64 count between cases and controls (<0.0001). In cases, except the nCD64 count (P=0.0079), all the four Kocher’s criteria tests showed insignificant difference between septic arthritis and transient synovitis cases. The sensitivity, specificity and Area under curve (AUC) for nCD64 count were maximum and were 0.50, 0.88 and 0.75 respectively. Addition of nCD64 count in Kocher’s criteria had increase their sensitivity, specificity and AUC from 0.30, 0.62 and 0.57 to 0.65, 0.93 and 0.95 respectively.

Conclusion: The CD64 count on neutrophils (nCD64) was the potential diagnostic test for septic arthritis and addition of nCD64 count in Kocher’s criteria may increase its reliability. This study will be very beneficial in clinical setup and public health in upcoming future.

Disclosure: The authors declared no competing interests.