Opioid therapy for knee osteoarthritis and postoperative persistent pain after knee arthroplasty

Extract

Drugs and pain in revision total knee arthroplasty

Knee OA is a common musculoskeletal disorder in middle-aged and elderly adults. The number of patients with this disorder is increasing, as the population increases in age, especially in the US, Japan and Western Europe. In Japan, 60% of women >80 years of age have complained of osteoarthritic knee pain [ 1 ]. Knee OA, as well as other musculoskeletal disorders, are treated primarily with non-surgical methods such as rehabilitation and NSAIDs.

Recently, because of their potent analgesic effect as well as concerns about severe side effects due to NSAIDs, opioids are becoming increasingly prevalent in treating musculoskeletal disorders, including knee OA. In the USA, prescriptions for patients with chronic non-cancer pain doubled from 8% in 1980 to 16% in 2000 [ 2 ]. A large-scale retrospective study with 15 160 chronic pain patients treated consecutively with opioids showed that 2% of these patients were at risk of developing opioid dependence. Patients with psychiatric disorders had an especially high risk of developing opioid dependence (odds ratio 1.46) [ 3 ]. Previous research on opioid efficacy was <1–2 years in duration [ 4 ], and no study has investigated the long-term efficacy of opioids for chronic non-cancer pain.