Which patients might benefit from platelet-rich plasma?

Ankle osteoarthritis

❯ ❯ ❯   Additional research is needed

Ankle OA affects 3.4% of all adults and is more common in the younger population than knee or hip OA.¹⁶ An RCT (N = 100) investigating PRP vs placebo (saline) injections showed no statistically significant difference in American Orthopedic Foot and Ankle Society scores evaluating pain and function over 26 weeks (–2 points; 95% CI, –5 to 1; P = .16).¹⁶ Limitations to this study include its small sample size and the PRP formulation used. (The intervention group received 2 injections of 2 mL of PRP, and the platelet concentration was not reported.)¹⁶

A 2020 systematic review and meta-­analysis of 4 RCTs and 5 case series by Evans et al¹⁷ concluded that PRP improves pain and function in small-joint OA compared to controls of saline, corticosteroids, and HA.¹⁷ One of the case series (N = 20) included in the study demonstrated improvement in ankle OA pain and function scores at 24 weeks posttreatment (P = .04), although improvement in pain and function peaked at 12 weeks.¹⁷ In addition, a 2017 retrospective study (N = 20) from the review reported improved VAS scores and function at 17 months following 4 injections of PRP over 4 weeks (P < .001).¹⁷ Given that RCT data found no benefit with PRP in treating small-joint OA, additional research is indicated.

Hip osteoarthritis

❯ ❯ ❯   Additional research is needed

Symptomatic hip OA occurs in 40% of adults older than 65 years, with a higher prevalence in women.¹⁸ Currently, corticosteroid injections are the only intra-articular therapy recommended by international guidelines for hip OA.¹⁹ A systematic review and meta-analysis comparing PRP to HA injections that included 4 RCTs (N = 303) showed a statistically significant reduction in VAS scores at 2 months in the PRP group compared to the HA group (weighted mean difference [WMD] = –0.376; 95% CI, –0.614 to –0.138; P = .002).¹⁸ However, there were no significant differences in VAS scores between the PRP and HA groups at 6 months (WMD = –0.141; 95% CI, –0.401 to 0.119; P = .289) and 12 months (WMD = –0.083; 95% CI, –0.343 to 0.117; P = .534). Likewise, no significant differences were found in WOMAC scores at 6 months (WMD = –2.841; 95% CI, –6.248 to 0.565; P = .102) and 12 months (WMD = –3.134; 95% CI, –6.624 to 0.356; P = .078) and Harris Hip Scores (HHS) at 6 months (WMD = 2.782; 95% CI, –6.639 to 12.203; P =.563) and 12 months (WMD = 0.706; 95% CI, –6.333 to 7.745; P = .844).¹⁸

A systematic review of 6 RCTs (N = 408) by Belk et al²⁰ comparing PRP to HA for hip OA found similar short-term improvements in WOMAC scores (standardized mean differences [SMD] = 0.27; 95% CI, –0.05 to 0.59; P = .09), VAS scores (MD = 0.59; 95% CI, –0.741 to 1.92; P = .39), and HHS (MD = -0.81; 95% CI, –10.06 to 8.43; P = .93). The average follow-up time was 12.2 and 11.9 months for the PRP and HA groups, respectively.²⁰

LR-PRP, which was used in 1 of the 6 RCTs, showed improvement in VAS scores and HHS from baseline, but no significant difference compared to HA at the latest follow-­up.²⁰ A pooled subanalysis of the 3 studies that used LP-PRP found no difference in WOMAC scores between the PRP and HA groups (SMD = 0.42; 95% CI, –0.01 to 0.86; P = .06).²⁰ Future studies comparing the efficacy of intra-articular steroid vs PRP for hip OA would be beneficial.¹⁸

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