Reference: Ann Fam Med 2013 May-Jun;11(3):229 (level 2 [mid-level] evidence)
A 65-year-old Caucasian male with history of right knee osteoarthritis presents to your clinic to discuss options for interventions other than physical therapy. What injection interventions are available for the treatment of this chronic non-inflammatory joint pain?
Care for knee osteoarthritis typically involves multiple modalities but with current systematic review evidence revealing a lack of one best therapy, alternate therapies abound, including the injection of inflammatory solutions to the insertion sites of tendons, ligaments and surrounding joint space, called prolotherapy (prolo- refers to “proliferant”). Dextrose is one of many inflammatory substances most commonly used in prolotherapy protocols; however, evidence for efficacy is limited.
To determine the efficacy of prolotherapy versus placebo and standard exercise physical therapy for the treatment of symptomatic knee osteoarthritis, 98 patients aged 40-76 with knee osteoarthritis for greater than 3 months were followed for one year after random assignment to one of 3 groups: prolotherapy (dextrose injections), sham prolotherapy (saline injections), or home-based knee exercises. The injector, outcome assessor, principal investigator, and the study participants were blinded to the injection received. Injection consisted of 22.5 mL extra-articular injections and 6 mL intra-articular injections performed at 1, 5, and 9 weeks and additionally at 13 and 19 weeks per physician discretion and patients’ preferences. Home exercise participants had a goal in 20 weeks to achieve a regimen of 15 repetitive exercises three times daily for 5 days a week. Primary outcomes were assessed with the Western Ontario McMaster University Osteoarthritis Index (WOMAC) questionnaire, which measure knee pain, stiffness, and function, with assessments done at baseline, 5, 9, 12, 26, and 52 weeks. Other outcomes included the knee pain scale (KPS) and patient satisfaction with treatment at study conclusion. Analyses were adjusted for baseline scores, age, sex, and body mass index.
At 52 weeks, all 90 patients who completed the study were improved from baseline. WOMAC scores of the prolotherapy group were significantly improved by 15.3 points from baseline compared to improvements in the sham prolotherapy group (7.6 points, p = 0.02) and the exercise group (8.2 points, p = 0.03). The authors note that a 12-point change on the WOMAC scale is considered the minimal clinically important difference. Thus, prolotherapy reveals clinically significant benefit over no treatment, but its benefit over exercise and sham prolotherapy is questionable. Also at 52 weeks, KPS scores of prolotherapy patients were reduced compared to sham-prolotherapy and exercise groups in both frequency (p < 0.05) and severity (p < 0.05). Interestingly all patients at the end of the study were similarly pleased with their treatment and would recommend it to others.
This study shows an improvement in knee osteoarthritis pain, stiffness, and function from dextrose prolotherapy compared to placebo, with possible improvement over sham prolotherapy (saline) and home knee exercises. Based on these results, dextrose prolotherapy is a potential intervention for chronic osteoarthritic pain management. However, more studies are needed to evaluate comparative efficacy with other interventions.
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