A Randomized Placebo Controlled Study to Determine the Efficacy of Oral Diclofenac Sodium in the Treatment of Symptomatic Osteoarthritis of the Knee in Nnewi, South Eastern Nigeria

Background: Diclofenac sodium is a non-selective non-steroidal anti-inflammatory drug (NSAID) that is widely used therapeutically for its analgesic and anti-inflammatory properties in the treatment of knee osteoarthritis (KOA) but no scientific study has been carried out at Nnewi, a town located in the Southeastern part of Nigeria to determine its therapeutic efficacy. The purpose of this study was to determine the efficacy of oral diclofenac sodium in the treatment of KOA in the local population using knee joint pain intensity, quadriceps muscle strength and 30.4 metres walk-time as outcome measures.

Materials and Methods: The research population comprised of participants who had symptomatic osteoarthritis of the knee according to the criteria established by the American College of Rheumatology (ACR). Seventy-six participants were randomly and equally distributed into two groups: the study group (oral diclofenac sodium) and control group (placebo). The participants in the study group were given one tablet of 50 mg diclofenac sodium and one tablet of vitamin B complex twice daily while those in the control group took only one tablet of vitamin B complex twice daily. Each participant in both groups took the drugs for seven consecutive weeks. The Statistical Package for Social Sciences (SPSS) version 20 software package was used for the data entry and analysis.

Results: Fifty-eight participants comprising of 19(32.8%) males and 39(67.2%) females completed this study. The male to female ratio was 1:2. There was a significant reduction in the knee joint pain intensity score in the study group at the end of seven weeks of treatment which was statistically significant (p=0.001) and also a statistically significant reduction in 30.4m walk-time of the participants in the study group (p=0.010), however there was no statistically significant change in the quadriceps muscle strength (p=0.056). There were no statistically significant changes in any of the outcome measures in the control group.

Conclusion: This study provides evidence to show that oral diclofenac sodium is efficacious in relieving symptoms in patients who have symptomatic KOA, when used with caution in selected patients at Nnewi.