Proponents of platelet-rich plasma (PRP)—an autologous blood derivative that isolates high concentrations of platelets and is rich in multiple growth factors and cytokines—have touted its use in the treatment of multiple orthopaedic ailments, from fracture healing to tendinopathy. But a closer look at the evidence supporting the use of PRP in soft-tissue injuries shows a more nuanced role for this popular biologic.

Meniscal repair
Data regarding the efficacy of PRP in meniscal repair are limited and mixed. To date, the best available evidence comes from animal models that used scaffolds for PRP deployment. For example, one study reported improved histologic scores at 12 weeks with use of a time-release gelatin hydrogel scaffold for PRP elution. However, no improvements were noted with PRP augmentation as compared to the control group in an additional study that used hyaluron-collagen scaffolds.

The evidence
Further investigation on the use of PRP in meniscal repair is warranted. Currently, no clear evidence for the efficacy of PRP in meniscal regeneration or repair exists.

Rotator cuff repair
Rotator cuff tears are common injuries. As a result, considerable research has focused on the use of biologics in rotator cuff repair. Studies have focused on tear location, morphology, time to fixation, the need for surgical repair, and the optimal surgical technique, among other issues.

Five randomized controlled trials (RCTs) and three nonrandomized trials on the use of PRP to augment healing in rotator cuff repair showed no clinical benefits as compared to controls. Furthermore, two of these studies actually suggested detrimental effects from PRP use.

A prospective study by Adam G. Bergeson, MD, and colleagues evaluated preoperative and postoperative MRI at 1 year, in addition to functional outcome scores, and found a statistically significant increase in retear rates in the group receiving augmentation with a platelet-rich fibrin matrix (PRFM). Similarly, Scott A. Rodeo, MD, and colleagues reported that PRFM augmentation did not demonstrate statistically significant differences with regard to healing at the tendon-bone interface, tendon vascularity, and patient-reported outcome scores. Furthermore, it was determined to be a statistically significant predictor for tendon defect at 12 weeks, suggesting that PRFM augmentation may have detrimental effects.

Results from other studies are consistent with these findings. In one, augmentation with autologous PRFM was found to have no added clinical benefit. A prospective study of 42 patients found no difference with regard to pain, motion, strength, retear rate, or subjective patient outcomes at 16-month follow-up.

According to an Italian study, however, a PRP injectable used in conjunction with an autologous thrombin component may have some benefits. Results of a double-blinded RCT showed more favorable Constant and UCLA patient-reported outcome scores, as well as better outcomes for grade-1 and grade-2 tears and lower rerupture rates.

A comprehensive systematic review of the literature evaluating PRP application in arthroscopic rotator cuff repair concluded: "PRP does not have an effect on overall retear rates or shoulder-specific outcomes after arthroscopic rotator cuff repair."

The evidence
Overall, multiple RCTs, nonrandomized trials, and a comprehensive systematic review of the literature show no clear benefit of PRP used to augment arthroscopic rotator cuff repair. In fact, two studies suggested possible detrimental effects. Although application of PRP with an added, autologous thrombin component may have a role, additional prospective randomized studies are required to determine the true efficacy of PRP use in arthroscopic rotator cuff repair.

Tendon healing
Two conditions that have received considerable attention with respect to PRP application are lateral epicondylar tendinosis (tennis elbow) and Achilles tendinopathy. Routine nonsurgical management of lateral epicondylar tendinosis consists of physical therapy, bracing, and corticosteroid injections into the tendon origin. Three studies—two Level I and one Level II—reported significant benefit with the application of PRP versus an injection of corticosteroid, bupivacaine, or autologous whole blood.

A single Level II study involved a cohort of patients who received an injection of either PRP or bupivacaine following 15 months of failed conservative management. At 8 weeks postinjection, the PRP group experienced a statistically significant improvement in visual analog scale (VAS) pain scores as compared to the bupivacaine group.

A single Level I study comparing PRP and corticosteroid injections found that patients treated with PRP had a statistically significant difference in successful reduction (> 25 percent) in VAS pain and Disabilities of the Arm, Shoulder, and Hand (DASH) scores at 1-year follow-up. At 2-year follow-up, patients in the PRP group reported continued improvement in both VAS pain and DASH scores compared to those who received corticosteroid injections.

Finally, a Level I RCT compared a single injection of PRP to single injection of autologous whole blood. In the group that received PRP, results demonstrated a statistically significant improvement in patient-reported VAS pain scores but no difference in the Liverpool Elbow Score.

Achilles tendinosis (midsubstance and insertional) is most commonly found in athletes and individuals with calf tightness. Treatment is primarily nonsurgical and may include rest, oral pain medications, physical therapy, bracing, orthotic use, and ultrasound.

PRP has been used in an attempt to improve and expedite the healing process of Achilles tendinosis, but results in this area have not been as favorable, with two recent RCTs reporting no significant improvement with PRP compared to saline injection. An additional study found that both PRP and saline injection resulted in a nonstatistical improvement of the mean Victorian Institute of Sports Assessment-Achilles score at 1-year follow-up. In a retrospective review of patients who had undergone intratendinous injection of PRP for midsubstance Achilles tendinopathy, Richard F. Owens, MD, and colleagues reported "modest improvement in functional outcome measures" with no change in Achilles tendon appearance, based on pre- and postinjection MRIs.

The evidence
In summary, the current literature demonstrates potential benefit for the use of PRP in the treatment of lateral epicondylar tendinosis. Both Level I and Level II studies demonstrate efficacy with improved patient-reported outcomes and pain scores. However, additional studies are needed with larger, double-blinded cohorts.

The literature does not currently support the use of PRP for midsubstance or insertional Achilles tendinopathy; further investigation is warranted to determine its efficacy.

Final thoughts
PRP therapy has many potential beneficial applications and has generated much excitement within the orthopaedic community. However, its use must be driven by sound evidence rather than by factors of industry and patient preference.

"As doctors, we need to provide treatment that is evidence-based rather than market-driven," said Freddie H. Fu, MD, chair of orthopaedic surgery at the University of Pittsburgh Medical Center. "Unnecessary medical treatments remain one of our biggest challenges."

Robert L. Parisien, MD, is an orthopaedic surgical resident at Boston University Medical Center in Boston. He can be reached at robert.l.parisien@gmail.com. David P. Trofa, MD, is an orthopaedic surgical resident at Columbia University Medical Center in New York City. Jesse Dashe, MD, is an orthopaedic surgical resident at Boston University Medical Center. Scott F. M. Duncan, MD, MPH, MBA, is chairman of the Department of Orthopaedic Surgery at Boston University Medical Center and a member of the AAOS Now editorial board.

Bottom Line

• Data on the efficacy of PRP in meniscal repair are limited and mixed; further investigation is necessary.
• Multiple RCTs, nonrandomized trials, and a comprehensive systematic review of the literature show no clear benefit when PRP is used to augment arthroscopic rotator cuff repair.
• The current literature demonstrates potential benefit for the use of PRP in the treatment of lateral epicondylar tendinosis.
• The use of PRP for midsubstance or insertional Achilles tendinopathy is not supported by the current literature.

Editor's Note: This is the second in a two-part series on the current evidence surrounding the uses of PRP in the nonsurgical management of musculoskeletal conditions. "PRP: Does It Do Anything?" (AAOS Now, February 2016).

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