Retrospective review of immobilization vs. immediate resumption of activity in patients with Oligoarticular juvenile idiopathic arthritis following knee injections

BACKGROUND: Intraarticular corticosteroid injection (IACI) is one of the most common treatments in oligoarticular Juvenile Idiopathic Arthritis (JIA). Activity recommendations following injection vary, as there are no published studies on splinting JIA patients post-IACI (splinting is a form of rest). Texas Scottish Rite Hospital for Children (TSRH) splints patients post-IACI for 24 h while The Children’s Hospital of Philadelphia (CHOP) does not. The aim of this study was to compare the number of cases of recurrent arthritis following IACI between these two post-injection practices. METHODS: Data were retrospectively collected at CHOP and TSRH. Patients diagnosed with oligoarticular JIA according to International League of Associations for Rheumatology (ILAR) criteria (2nd revision, 2001) between 2008 and 2010 were included. Bivariate analysis (Wilcoxon rank-sum tests, chi-squared tests) was run to assess differences in outcomes by site. Inverse probability of treatment weighted Cox regression was employed to adjust for site differences. RESULTS: The population at TSRH was younger than at CHOP (p < 0.05) and had more whites (p = 0.03). Disease duration was significantly longer at TSRH than at CHOP (0.40 vs. 0.74 years, p = 0.014). More children were on biologics at the time of injection at CHOP (p < 0.05). The baseline physician global (p < 0.001) was higher at CHOP, as was the joint disease severity (p < 0.001). CHOP had fewer reoccurrences of knee arthritis compared to TSRH: 26% vs 38% (p = 0.14). CONCLUSIONS: The baseline populations were different in that the TSRH group had more whites and Hispanics, were younger and, perhaps, had less severe disease than CHOP. Patients treated with post-injection splinting had a trend toward more arthritis reoccurrence (38% vs. 26%, p = 0.14). Splinting is not clearly beneficial post-injection. TRIAL REGISTRATION: This is an observational study, so it is not applicable. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12969-019-0339-0) contains supplementary material, which is available to authorized users.