Interventions
pain
All patients received three IA PN (20 mg/ml) injections or three IA HMWHAs (20 mg/2 ml) injections at intervals of 1 week. In each institute, the injection was aseptically administered by an independent, skillful orthopedic surgeon. The first injection was administered at the beginning of the treatment (baseline), and the second and third injections were administered at 1 week and 2 weeks from the baseline, respectively. After three IA injections, patients were followed up at 8 weeks and 16 weeks for clinical evaluation. During the study period, use of Acetaminophen (≤ 4 g/day) were allowed for the pain rescue drug (Fig. Study flow diagram.