Joost Peerbooms

75 PRP in lateral epicondylitis reinjection with corticosteroids did not see a resolution of pain and disability, according to the mentioned criteria. Successful treatment was defined as more than a 25% reduction in VAS or DASH score without a reintervention after 1 year. The results showed that 24 of the 49 patients (49%) in the corticosteroid group and 37 of the 51 patients (73%) in the PRP group were successful with the VAS score, which was significant ( P < .001). Twenty-five of the 49 patients (51%) in the corticosteroid group and 37 of the 51 patients (73%) in the PRP group were successful with the DASH score, which was also significant ( P = .005). No fevers or rashes were reported. Apart from the local inflammation causing increased pain 3 to 4 weeks after the injection, no systemic or other local reactions were seen. The effect can be characterized as a local mechanism, without systemic side effects. If we set the criteria for success at 50% or 75% improvement of both scores (instead of 25% improvement), the results still show significant differences between both groups, as shown in Tables 3 and 4. Table 3 Pain Resolution for the Corticosteroid (CS) and Platelet-Rich Plasma (PRP) Groups Pain Reduction Percentage Pain Reduction (%) a Time, wks Group n Average ± SE t >75% 50%-75% 25%-50% <25% x 2 4 CS 51 –21.6 ± 3.5 17.6 15.7 19.6 47.1 PRP 48 –15.8 ± 3.6 .14 4.2 10.4 29.2 56.3 .12 8 CS 51 –22.9 ± 4.0 23.5 11.8 17.6 47.1 PRP 48 –22.9 ± 3.5 .99 12.5 16.7 31.3 39.6 .22 12 CS 51 –21.6 ± 3.6 15.7 21.6 15.7 47.1 PRP 48 –31.1 ± 4.2 .09 18.8 33.3 14.6 33.3 .46 26 CS 51 –9.3 ± 3.1 3.9 7.8 27.5 60.8 PRP 49 –37.4 ± 4.6 < .001 40.8 18.4 10.2 30.6 < .001 52 CS 50 –15.7 ± 3.5 13.7 9.8 23.5 52.9 PRP 49 –44.8 ± 4.4 < .001 57.1 8.2 10.2 24.5 <.001 α For all patients, the pain reduction score is classified as > 75%, 50%-75%, 25%-50%, or < 25% pain reduction. For all time points, the percentage of patients in each category is calculated. The 2 groups are compared with the Chi-square test. 5