Question 1. What evidence is available regarding symptom-modifying and disease-modifying changes after a single IA injection to treat OA?
Twenty-three articles were included to answer question 1. Of these, 16 focused on humans (12 RCTs, one crossover, one case-control, one retrospective cohort, and one pilot) (Gaffney et al., 1995; Jones & Doherty, 1996; Young et al., 2001; Carette et al., 2003; Meenagh et al., 2004; Heyworth et al., 2008; Chao et al., 2010; Leung et al., 2011; Yavuz et al., 2012; Gialanella & Bertolinelli, 2013; Lattermann et al., 2017; Shrestha et al., 2018; Mendes et al., 2019; Okike et al., 2021; Latourte et al., 2022; Nunes-Tamashiro et al., 2022). Seven studies included horses as the study subjects (five pre-clinicalin vivo and two RCTs) (Todhunter et al., 1998; Fubini et al., 2001; Kay et al., 2008; de Grauw et al., 2016; Ekstrand et al., 2019; Kearney et al., 2021; de Clifford et al., 2021). The risk of bias was considered unclear/high in most studies, with only four RCTs, one crossover, and one retrospective pilot study having a low risk of bias (Figure 3).
Lesions investigated in studies included (in humans) knee OA (ten studies), anterior cruciate ligament injury (one study), rapidly destructive hip disease (RDHD) (one study), shoulder adhesive capsulitis (one study), shoulder rotator cuff tendinopathy (one study), and OA of the carpometacarpal joint of the thumb (two studies). In horses, there was lipopolysaccharide-induced joint inflammation of the fetlock/carpus (five studies), naturally occurring middle carpal joint OA (one study), and lameness associated with joint pain (responsive to IA block) (one study). Human studies included 40 to 465 patients, with one study reporting the number of joints as the experimental unit (757 joints). This experimental unit was primarily employed in equine investigations in which sample numbers ranged from 11 to 41 joints. TA was the most investigated corticosteroid (ten studies; doses were 9–12 mg for horses and 40–80 mg for humans), followed by TH (five studies; doses of 5–40 mg for humans), MPA (five studies, 0.1 mg/kg for horses and 40–120 mg for humans), BTM (two studies; 3–6 mg for humans), and DEX (one study; 0.01–3 mg for horses). The specific corticosteroid type employed was not mentioned in two studies in which authors investigated the effects of IA corticosteroids in general. Follow-up varied from 48 hours to 6 weeks in equine studies and four weeks to five years in human investigations.