Platelet-Rich Plasma Injections for the Treatment of Ankle Osteoarthritis

Abstract

Background: Ankle osteoarthritis is debilitating and usually affects relatively young people, often as a result of previous ankle traumas, frequently occurring in sports. Platelet-rich plasma (PRP) injections for ankle osteoarthritis have shown no evidence of benefit over the course of 26 weeks. Previous studies on PRP for knee osteoarthritis showed that clinically significant improvements with PRP occurred between 6 to 12 months in the absence of initial benefit. No studies have evaluated the effect of PRP from 6 to 12 months in ankle osteoarthritis.

Purpose: To assess the efficacy of PRP injections in ankle osteoarthritis over the course of 52 weeks.

Study design: Randomized controlled trial; Level of evidence, 1.

Methods: In this 52-week follow-up trial, 100 patients with ankle osteoarthritis were randomized to a PRP group or placebo (saline) group. Patients received 2 intra-articular talocrural injections: at inclusion and after 6 weeks. Patient-reported outcome measures were used to assess pain, function, quality of life, and indirect costs over 52 weeks.

Results: Two patients (2%) were lost to follow-up. The adjusted between-group difference for the patient-reported American Orthopaedic Foot & Ankle Society score over 52 weeks was -2 points (95% CI, -5 to 2; P = .31) in favor of the placebo group. No significant between-group differences were observed for any of the secondary outcome measures.

Conclusion: For patients with ankle osteoarthritis, PRP injections did not improve ankle symptoms and function over 52 weeks compared with placebo injections.

Registration: NTR7261 (Netherlands Trial Register).

Keywords: ankle osteoarthritis; orthopaedic sports medicine; osteoarthritis; platelet-rich plasma; sports medicine.

Figure 1.

Participant recruitment, randomization, and follow-up to week 52 (secondary endpoint). ^a van Dijk classification using ankle radiograph: 0, normal joint or subchondral sclerosis; 1, osteophytes without joint space narrowing; 2, joint space narrowing with or without osteophytes; 3, (sub)total disappearance or deformation of the joint space. ^b Before each consultation, the questionnaires were checked for completeness. A reminder was sent via email in the event of incompleteness. One patient did not complete the secondary outcome questionnaires at 52 weeks because he thought it was too time-consuming. One patient died from an unrelated disease before 52 weeks. OA, osteoarthritis; PRP, platelet-rich plasma; VAS, visual analog scale.

Figure 2.

Mean scores for the unadjusted, patient-reported version of the American Orthopaedic Foot & Ankle Society score in patients treated with platelet-rich plasma (PRP) and placebo (range, 0-100 points; higher scores indicate less pain and better function). See Table 2 notes for scale definitions. The horizontal lines in the boxplots from bottom to top show the 25th, 50th (median), and 75th percentiles. The X in the boxplot indicates the mean. The whiskers indicate the 25th percentile −1.5 × IQR and the 75th percentile −1.5 × IQR. Baseli, baseline; IQR, interquartile range.

Figure 3.

Change in unadjusted American Orthopaedic Foot & Ankle Society (AOFAS) score (range, 0-100 points; higher scores indicate less pain and better function) for each participant by group at baseline and 52 weeks. The baseline patient-reported AOFAS scores for individual participants are connected with a line. See Table 2 notes for scale definitions. Changes from baseline are represented by the vertical lines for platelet-rich plasma (PRP) and placebo. Upward and downward lines indicate improvement and deterioration, respectively. The boxplots (from left to right) show the summary at pre- and postinjection for PRP, at pre- and postinjection for placebo, and the changes by group. The horizontal lines in the boxplots from bottom to top show the 25th, 50th (median), and 75th percentiles. The dot in the boxplot indicates the mean. The whiskers indicate the 25th percentile −1.5 × IQR and the 75th percentile −1.5 × IQR. IQR, interquartile range; Post, postinjection; Pre, preinjection.

Figure 4.

Unadjusted secondary outcomes over the 52-week follow-up period (secondary endpoint). (A) Ankle Osteoarthritis Scale, (B) visual analog scale, (C) 36-Item Short Form Health Survey (SF-36) Mental Component Summary, and (D) SF-36 Physical Component Summary, at baseline and 6, 12, 26, and 52 weeks. The horizontal lines in the boxplots from bottom to top show the 25^th, 50^th (median), and 75^th percentiles. The X in the boxplot indicates the mean. The whiskers indicate the 25^th percentile −1.5 × IQR and the 75^th percentile −1.5 × IQR. IQR, interquartile range; PRP, platelet-rich plasma.