A randomised trial of a brace for patellofemoral osteoarthritis targeting knee pain and bone marrow lesions.

OBJECTIVE: Braces used to treat (PF) osteoarthritis (OA) may reduce contact stress across the PF joint. We hypothesised that in PF OA, braces would decrease knee pain and shrink PF bone marrow lesions (BMLs). METHODS: Eligible subjects had painful PF OA. Subjects were randomly allocated to brace or no brace for 6 weeks. Knee MRIs were acquired at baseline and 6 weeks. We measured BMLs on post-contrast fat suppressed sagittal and proton density weighted axial images. The primary symptom outcome was change in pain at 6 weeks during a preselected painful activity, and the primary structural outcome was BML volume change in the PF joint. Analyses used multiple linear regression. RESULTS: We randomised 126 subjects aged 40-70 years (mean age 55.5  years; 72 females (57.1%)). Mean nominated visual analogue scale (0-10 cm) pain score at baseline was 6.5 cm. 94 knees (75%) had PF BMLs at baseline. Subjects wore the brace for a mean of 7.4 h/day. 6 subjects withdrew during the trial. After accounting for baseline values, the brace group had lower knee pain than the control group at 6 weeks (difference between groups -1.3 cm, 95% CI -2.0 to -0.7; p<0.001) and reduced PF BML volume (difference -490.6 mm(3), 95% CI -929.5 to -51.7; p=0.03) but not tibiofemoral volume (difference -53.9 mm(3), 95% CI -625.9 to 518.2; p=0.85). CONCLUSIONS: A PF brace reduces BML volume in the targeted compartment of the knee, and relieves knee pain. TRIAL REGISTRATION NUMBER: UK. ISRCTN50380458.

Sensitivity to Change of Patient-Preference Measures for Pain in Patients With Knee Osteoarthritis: Data From Two Trials.

OBJECTIVE: In osteoarthritis (OA) clinical trials, a pain measure that is most sensitive to change is considered optimal. We compared sensitivity to change of patient-reported pain outcomes, including a patient-preference measure (where the patient nominates an activity that aggravates their pain). METHODS: We used data from 2 trials of patients with confirmed (American College of Rheumatology criteria) knee OA: a trial of brace treatment for patellofemoral OA, and a trial of intraarticular steroids in knee OA. Both trials reported an improvement in pain following treatment. Participants rated pain on a 100-mm visual analog scale (VAS), in the activity that caused them the most knee pain (VASNA ), as well as completing questions on overall knee pain and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were also calculated from the KOOS. Standardized changes in each outcome were generated between treatment and control after 6 weeks intervention in the BRACE trial, and 1-2 weeks following intervention in the steroid trial. RESULTS: The VASNA produced standardized changes following treatment that were at least as large as other pain outcomes. In the BRACE trial, the between-groups standardized change with the VASNA was -0.63, compared with the KOOS pain subscale change of -0.33, and pain in the last week VAS change of -0.56. In the steroid study, within-group change following treatment in the VASNA was -0.60, compared to the last week VAS change of -0.51, and KOOS pain subscale change of -0.58. CONCLUSION: Pain on nominated activity appears to be at least as, and in some cases more, sensitive to change than the KOOS/WOMAC questionnaire.