101 patients (106 shoulders) were randomized to investigate the efficacy of either an intra-articular injection or periarticular injection in the treatment of symptomatic acromioclavicular joints. Outcome measurements of pain and function were assessed up to 3 weeks post-injection. The results indicated that either injection provided similar, significant improvements in pain and function. There was no difference observed between groups, with the exception that less pain during the crossover arm test (COAT) was reported among participants treated with an intra-articular injection.