Comparison of Clinical Efficacy between Nonsteroidal Anti-inflammatory Drugs and Acetaminophen in Knee Osteoarthritis according to Ultrasonographic Findings

Do, Ju Ho; Hur, Sung Eun; Paek, Seung In; Nah, Jong Myoung; Kim, Choong Hyun; Lee, Sang Heon; Park, Sung Hwan; Cho, Chul Soo; Kim, Ho Youn; Kim, Wan Uk

Abstract

OBJECTIVE
To compare the clinical efficacy between nonsteroidal antiinflammatory drugs (NSAIDs) and acetaminophen in knee osteoarthritis according to ultrasonographic findings.
METHODS
We administered 12 mg of NSAIDs (lornoxicam) plus misoprostol 300microgram or 1,950 mg of acetaminophen in 40 randomly selected patients who fulfilled the ACR criteria for knee osteoarthritis. The effectiveness of these drugs on osteoarthritis was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. In addition, we performed ultrasonography of the knee joints and assessed length of capsular distension, length of medial and lateral osteophyte, amount of joint effusion, and the presence of synovial proliferation.
RESULTS
There were significant correlations between WOMAC score and length of capsular distension and length of medial/lateral osteophyte. At 6 weeks, both lornoxicam and acetaminophen-treated patients had significant lower levels of WOMAC score compared to the entry into the trial (p<0.01 and p<0.05, respectively). As compared the clinical efficacy between the two groups, the lornoxicam-treated patients showed a greater decrease in WOMAC score than patients treated with acetaminophen (p=0.026). When we further divided the patients into the subgroups according to the sonographic severity, the patients with severe capsular distension (> or =0.7 cm) or severe medial osteophyte (length of osteophytes > or =0.4 cm) showed better responses to lornoxicam than to acetaminophen in terms of the reduction of WOMAC score (p=0.008 for severe capsular distension, p=0.03 for severe medial osteophyte). However, in the subgroup with mild forms of capsular distension (<0.7 cm) or medial osteophytes (<0.4 cm), no difference was found in the reduction of WOMAC score 6 weeks after treatment with lornoxicam versus acetaminophen.
CONCLUSIONS
Patients with osteoarthritis of the knee had significantly greater improvements in pain score over 6 weeks with lornoxicam than with acetaminophen, particularly in patients with severe forms of capsular distension and medial osteophyte on joint ultrasonography. Ultrasonography could be an useful tool to determine the usage of NSAIDs versus acetaminophen in knee osteoarthritis patients.