In this study, investigators compared the efficacy of intra-articular 0.5% lidocaine and saline injection on pain, stiffness and physical function in patients with osteoarthritis.

Patients with osteoarthritis were randomly allocated into two groups. Group I (n=26) received intra-articular injection of 7 mL 0.5% lidocaine and Group II (n=26) received 7 mL saline into painful knee for 3 times with one week intervals under USG guidance. VAS and WOMAC scale including pain, stiffness and physical function was used for the assessment of patients with osteoarthritis. Analgesic requirements were also recorded.

The primary outcome parameter of this study was the pain scores. The sample size for the primary variable was calculated based on a standard deviation of 20 mm estimated from a previous study. A power analysis with a type II error of 20% at a two-sided 5% significance level estimated 22 patients per group to be included. Investigators included 26 patients per groups for possible missing date. χ2 test for categorical data and independent samples t-test for the comparison of VAS and WOMAC scores between groups were used for statistical analysis.

Inclusion Criteria:

• knee pain for more than 25 of the past 30 days, morning stiffness or less than 30 minutes, crepitation in the knee
• pain for more than 25 of the past 30 days and osteophytes on x-ray examination of the knees indicating knee OA

Exclusion Criteria:

• the knees with a history of mechanical derangement, fibromyalgia, skin lesions and other risk factors of infection, therapy with anticoagulants and trauma/surgery