PRP not superior to HA injections for treatment of knee degenerative pathology
Platelet-rich plasma vs hyaluronic acid to treat knee degenerative pathology: study design and preliminary results of a randomized controlled trialBMC Musculoskelet Disord. 2012 Nov 23;13:229. doi: 10.1186/1471-2474-13-229
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109 patients with degenerative knee cartilage were randomized to determine the efficacy of platelet-rich plasma (PRP) compared to viscosupplementation via hyaluronic acid (HA) as a treatment method. Patients were allocated to three injections of either solution, and were followed up for 12 months. Results revealed that there were no differences between groups in clinical outcome for the duration of the study. Interestingly, a sub-group analysis of patients with lower degenerative status (Kellgren-Lawrence grade 0-II) indicated a trend of improved outcome with PRP, but did not reach statistical significance.
Was the allocation sequence adequately generated?
Was allocation adequately concealed?
Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?
Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?
Blinding Patients: Was knowledge of the allocated interventions adequately prevented?
Was loss to follow-up (missing outcome data) infrequent?
Are reports of the study free of suggestion of selective outcome reporting?
Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?
Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?
Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?
Yes = 1
Uncertain = 0.5
Not Relevant = 0
No = 0
The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.
Inclusion / Exclusion
Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.
Why was this study needed now?
While participation in sports activity continues to grow among the entire population as a means of maintaining a healthy lifestyle, so to does the incidence of knee cartilage pathologies. As a result, numerous treatment methods have been suggested in the management of these conditions, although the efficacy of these treatments is often limited in both time and satisfaction. A developing treatment option is in platelet-rich plasma (PRP), which has shown a potential beneficial effect in the regeneration of damaged tissue through the release of concentrated growth factors. While promising findings have been reported, high level evidence in support of PRP remains lacking.
What was the principal research question?
Was the application of PRP more efficacious than viscosupplementation with hyaluronic acid (HA) after 12 months as a method of treatment for knee cartilage pathologies?
What were the important findings?
- IKDC subjective score in the PRP group was increased from 50.2 (SD 15.7) at baseline to 62.8 (SD 17.6) at 2 months, 64.3 (SD 16.4) at 6 months and 64.9 (SD 16.8) at 12 months. Corresponding values in the HA group were 47.4 (SD 15.7), 61.4 (SD 16.2), 61.0 (SD 18.2), and 61.7 (SD 19.0), respectively. Although intra-group improvements were significant, there was no statistically significant difference observed between groups.
- No significant differences were observed between groups in EQ-VAS scores, nor in overall KOOS score or in individual KOOS subcategories (pain, activity of daily life, sport, quality of life), despite significant intra-group improvements.
- Activity level on the Tegner scale in the PRP group was improved from 2.9 (SD 1.4) at baseline to 3.8 (SD 1.3) at 12 months, and in the HA group from 2.6 (SD 1.2) at baseline to 3.4 (SD 1.6) at 12 months.
- Sub-analysis of IKDC subjective score in patients with Kellgren Lawrence 0-II revealed a trend of improved outcomes at 6 and 12 months in those with low grade degeneration, although statistical significance was not reached (p=0.08 at 6 months, p=0.07 at 12 months).
- Injections of PRP were associated with higher post-injection pain reaction compared to HA injections (p=0.039); reaction was self-limiting within a few days and did not impact overall outcome.
What should I remember most?
Both treatments resulted in significant improvements in clinical scores. Clinical outcome of platelet-rich plasma injections for knee cartilage pathologies was not superior to viscosupplementation with hyaluronic acid injections, as similar IKDC, KOOS, EQ-VAS and Tegner activity scores were observed between treatment methods. Outcome in patients with lower graded degeneration (Kellgren-Lawrence 0-II) showed a trend of improved outcome, albeit without significance.
How will this affect the care of my patients?
The findings of this research suggest that treatment of knee cartilage pathologies is not better with PRP injection compared to HA injection, and does not support the use of PRP as first line treatment in this population. However, due to the trend observed in a sub-analysis of this study, future research should be considered for evaluating the efficacy of PRP exclusively in patients with lower degenerative status.
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