PRP Injection Resulted in Joint Replacement Avoidance in 568 OA Knees at 3 - 7 Year Follow-Up, Even Bone on Bone

Purpose: Most knee PRP studies report only short-term results and fail to assess total knee replacement (TKR) avoidance/joint survivorship as an outcome. We wished to evaluate the efficacy of PRP at 3-year follow-up with particular attention to TKR avoidance.

Methods and Materials: This prospective study examines the outcomes of patients with medial and lateral KOA who were treated with PRP and followed for 3 to 7 years. 568 knees (487 patients) with KOA were treated with PRP injections. All patients had medial or lateral KOA diagnosed by physical exam and confirmed by x-ray. Outcomes included joint survivorship, global improvement, safety, Single Assessment Numeric Evaluation (SANE) scores, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Evaluations were performed 6 months, 1 year, 18 months, 2 years, and 3 years after treatment.

Results: 207 males and 280 females with a mean age of 65 years were treated. 456 patients had medial KOA and 112 had lateral KOA. No serious adverse events were seen. Patients were separated into 6 groups based on joint space measured on standing AP x-ray (0-1mm, 2-4mm, and 5+mm) and site of KOA (medial or lateral). 101 knees received total knee arthroplasty (TKA) by 36 months, for a total survivorship of 75% at 3 years. Survivorship was 64% for the 0-1mm group, 77% for the 2-4mm group, and 91% for the 5+mm group at 3 years. There were significant improvements in both SANE scores and WOMAC scores by 6-month follow up and these improvements were maintained throughout the three-year follow-up. Linear regression analysis demonstrated no significant change in efficacy when factoring in BMI and age.

Conclusion: PRP for the treatment of medial and/or lateral KOA has excellent survivorship out to 3 years even in bone-on-bone, elderly, and obese patients.