PURPOSE: To assess the short-term results of repeated intra-articular platelet rich plasma (PRP) injections into the knee in patients with early osteoarthritis (OA) and to determine a better treatment protocol.
METHODS: This is a retrospective study in 191 knees (127 patients) with minimum of 12 months follow-up. We compared the clinical results of three types of injection method, once a month, twice monthly, and three injections at monthly interval. The outcomes were assessed using Visual Rating Scale (VRS), functional score, knee score, range of motion (ROM), WOMAC Stiffness/Pain/Function score, IKDC score, before the first injection and at 12 months post treatment.
RESULTS: There were significant improvements in all scores after treatment as compared to the pre-treatment values (p < 0.05), except Knee score after 1st and 2nd injection and ROM in three groups. The parameters of Visual Rating Scale (VRS), functional score, and WOMAC Stiffness/Pain/Function score showed significant differences among the three groups in favour of the three injections group (p < 0.05). At 12 months, the effects began to decline in one injection and two injections groups, and the data in one injection group showed significant difference compared to two injection group (p < 0.001). Three injections group had higher scores and more improvement at 12 months after treatment when compared to the other two groups.
CONCLUSION: PRP injection appears to be effective in early symptomatic OA knees. The results after treatment are encouraging with significant reduction in pain and improvement in knee function at 12 months after treatment when compared to the pre-treatment status. Three injections per month yielded significantly better results in short-term follow-up.