The Effects of Platelet-Rich Plasma on Tendon and Ligament: Basic Science and Clinical Application

Role of platelet-rich plasma in the treatment of rotator cuff tendinopathy

Shoulder pain is a common musculoskeletal complaint, and rotator cuff (RC) pathologies are one of the main causes. The RC undergoes various tendinopathic and avascular changes during the aging process. Other degenerative changes affecting its healing potential make it an appealing target for biological agents. Platelet-rich plasma (PRP) has demonstrated the potential to deliver a high concentration of several growth factors and anti-inflammatory mediators, and its clinical use is mainly supported by experiments that demonstrated its positive effect on muscle, ligaments, and tendinous cells. This review aimed to specify the role of PRP and its future applications in RC tendinopathies based on the current clinical evidence. Due to the different characteristics and conflicting outcomes, clinicians should use PRP with moderate expectations until more consistent evidence is available. However, it is reasonable to consider PRP in patients with contraindications to corticosteroid injections or those with risk factors for inadequate healing. Its autologous origin makes it a safe treatment, and its characteristics make it a promising option for treating RC tendinopathy, but the efficacy has yet to be established.

Editorial Commentary: Platelet-Rich Plasma Shows Promise for Improving Shoulder Tendinopathy

Platelet-rich plasma (PRP) injections continue to be used at increasing rates to treat common musculoskeletal conditions. PRP has a low-risk profile and emerging in vitro evidence to support its positive effects on soft-tissue healing. PRP has been shown to be of benefit for knee osteoarthritis, but less has been published regarding the shoulder. PRP delivers a high concentration of growth factors, cytokines, and other important inflammatory modulators. Its use is appealing for treating partial-thickness rotator cuff tears, subacromial bursitis, and rotator cuff tendinopathy since rotator cuff tendons often have poor healing capacity due to intrinsic degeneration. PRP has been shown to increase cell proliferation and matrix synthesis in tenocytes, which may aid tendon regeneration and healing. Adult tendons also contain a small amount of tendon progenitor cells, which can be induced to an active state by PRP. In addition, PRP is an autologous biologic agent and easy to acquire and administer in an outpatient clinical setting. Clinical studies continue to lag and are often heterogenous in quality and in results. PRP can vary widely based on multiple intrinsic and extrinsic factors, including patient age, sex, activity level, centrifugation speed, and number of centrifugation cycles. Thus, quality research methods should include reporting using the PAW (platelets/activation/white blood cells) system. Clinicians should remain cautiously optimistic about the future role of PRP injections in the shoulder.

Methodological variations affect the release of VEGF in vitro and fibrinolysis' time from platelet concentrates

Blood Concentrates (BCs) are autologous non-transfusional therapeutical preparations with biological properties applied in tissue regeneration. These BCs differ in the preparation method, in fibrin network architecture, growth factors release as well as in platelet/cell content. Methodological changes result in distinct matrices that can compromise their clinical effectiveness. The present study evaluated the influence of different g-forces and types of tubes in the release of vascular endothelial growth factor (VEGF) from platelet-rich fibrin (PRF) as a function of time. The PRF-like samples were obtained with three g-forces (200, 400, and 800 x g) for 10 minutes in pure glass tubes or in polystyrene-clot activator tubes. Scanning and Transmission electron microscopy was used to morphometric analyzes of PRF’s specimens and flow cytometry was used to quantify VEGF slow release until 7 days. Our results showed that platelets were intact and adhered to the fibrin network, emitting pseudopods and in degranulation. The fibrin network was rough and twisted with exosomic granulations impregnated on its surface. An increase in the concentration of VEGF in the PRF supernatant was observed until 7 days for all g forces (200, 400 or 800 xg), with the highest concentrations observed with 200 x g, in both tubes, glass or plastic. Morphological analyzes showed a reduction in the diameter of the PRF fibers after 7 days. Our results showed that g-force interferes with the shape of the fibrin network in the PRF, as well as affect the release of VEGF stored into platelets. This finding may be useful in applying PRF to skin lesions, in which the rapid release of growth factors can favor the tissue repair process. Our observations point to a greater clarification on the methodological variations related to obtaining PRF matrices, as they can generate products with different characteristics and degrees of effectiveness in specific applications.

Treatment of lateral ankle sprain with platelet-rich plasma: A randomized clinical study

BACKGROUND

We aimed to clinically evaluate the effect of platelet-rich plasma (PRP) therapy in patients with acute lateral ankle sprain treated with rigid immobilization.

METHODS

Patients with first-time grade II lateral ankle sprain clinically diagnosed were evaluated (n=21). A rigid immobilization was placed in all patients for ten days; previously, an application of PRP over the anterior talofibular ligament was performed in patients from the experimental group. The Visual Analogue Scale, the American Orthopedic Foot and Ankle Score, and the Foot and Ankle Disability Index were applied at 3, 5, 8 and 24 weeks of follow-up period.

RESULTS

The experimental group presented the highest reduction in pain and better functional scores than the control group at 8 weeks. At the end of follow-up period the results of both groups were similar.

CONCLUSIONS

A similar evolution was observed in patients treated with rigid immobilization with or without PRP after 24 weeks.

TRIAL REGISTRATION

Clinical Trials.gov with ID NCT02609308.

The role of biologic agents in the management of common shoulder pathologies: current state and future directions

The field of orthopedic surgery has seen a rapid increase in the use of various biologic agents for the treatment of common musculoskeletal injuries. Most biologic agents attempt to harness or mimic naturally occurring growth factors, cytokines, and anti-inflammatory mediators to improve tissue healing and recovery. The most commonly used biologic agents are platelet-rich plasma and cells derived from bone marrow aspirate and adipose tissue. These agents have become increasingly popular despite a relative dearth of clinical data to support their use. Much confusion exists among patients and physicians in determining the role of these agents in treating common shoulder pathologies, such as glenohumeral osteoarthritis, rotator cuff tears, and tendinopathy. This article reviews the basic science and clinical evidence for the most commonly used biologic agents in the management of common shoulder pathology.

Clinical efficacy and safety of platelet-rich plasma in arthroscopic full-thickness rotator cuff repair: A meta-analysis

BACKGROUND

Arthroscopic repair of rotator cuff tears, although commonly performed, carries the risk of retears. Therefore, bioremediation techniques such as platelet-rich plasma injections have been used as adjuvant therapies. The clinical efficacy of platelet-rich plasma in the arthroscopic repair of full-thickness rotator cuff injury is controversial. We performed a meta-analysis to evaluate the clinical effectiveness and safety of platelet-rich plasma and provide evidence-based medical recommendations for selecting the proper clinical treatment plan for full-thickness rotator cuff injuries.

METHODS

A search for the terms "platelet-rich plasma" and "rotator cuff" was performed in the PubMed, EMBASE, and Cochrane Library databases using a computer. After conducting quality evaluations and data extraction, RevMan 5.3 software was used to combine the effect sizes, and the GRADEpro Guideline Development Tool was used to rate the level of evidence from aspects of functional score, pain score and retear rate.

RESULTS

Eight randomized controlled trials involving 566 patients were included. The long-term retear rate(RR = 0.96, 95% CI [0.52, 1.78], P = .89), Constant score(RR = 0.96, 95% CI [0.52, 1.78], P = .89), and Visual Analog Scale score for pain (SMD = -0.28, 95% CI [-0.60, 0.04], P = .08), as well as both the long-term and short-term Disabilities of the Arm, Shoulder, and Hand scores(SMD = -0.13, 95% CI [-0.44, 0.18], P = .41;SMD = -0.02, 95% CI [-0.40, 0.36], P = .93), were not significantly different between the platelet-rich plasma and control groups. However, the short-term retear rate(RR = 0.29, 95% CI [0.13, 0.65], P = .003) and Visual Analog Scale score (SMD = -0.41, 95% CI [-0.62, -0.19], P = .0002) were significantly lower, while the short-term Constant score(SMD = 0.37, 95% CI [0.19, 0.55], P < .0001) and short-term and long-term University of California at Los Angeles activity scores (SMD = 0.38, 95% CI [0.16, 0.60], P = .0008;SMD = 0.85, 95% CI [0.48, 1.22], P < .00001) were significantly higher, in the platelet-rich plasma group than in the control group.

CONCLUSION

Platelet-rich plasma injection can effectively improve the short-term outcomes following arthroscopic repair of full-thickness rotator cuff tears, thus reducing the rate of retears, alleviating pain, and improving patients' shoulder function. Specifically, the clinical outcomes are better with the use of platelet-rich plasma in single-row fixation than in other fixation techniques. Therefore, platelet-rich plasma injection can be recommended as an adjuvant therapy in single-row repair for improved short-term results.

Platelet-Rich Plasma: Review of Current Literature on its Use for Tendon and Ligament Pathology

PURPOSE OF REVIEW

Platelet-rich plasma (PRP) contains numerous growth factors and cytokines that potentially offer an alternative treatment modality to assist in the healing of multiple musculoskeletal issues. The purpose of this review was to examine the latest literature on the use of PRP for various ligament and tendon pathologies.

RECENT FINDINGS

Recent literature has shown moderate- to high-quality evidence that PRP can have positive clinical effects in certain conditions such as lateral epicondylitis and rotator cuff tendinopathy. Prospective studies have shown that it can also be useful in the treatment of patella tendinopathy. In summary, we found PRP to have variable success in ligament and tendon pathology; however, it should be considered a viable option in chronic musculoskeletal disease that has failed other treatments. Patient selection, duration of symptoms, and combining with other modalities such as physical therapy should all be taken into consideration in treatment with PRP.

Do postoperative platelet-rich plasma injections accelerate early tendon healing and functional recovery after arthroscopic supraspinatus repair? A randomized controlled trial

BACKGROUND

Tendon-bone healing after rotator cuff repair directly correlates with a successful outcome. Biological therapies that elevate local growth-factor concentrations may potentiate healing after surgery.

PURPOSE

To ascertain whether postoperative and repeated application of platelet-rich plasma (PRP) to the tendon repair site improves early tendon healing and enhances early functional recovery after double-row arthroscopic supraspinatus repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 60 patients underwent arthroscopic double-row supraspinatus tendon repair. After randomization, half the patients received 2 ultrasound-guided injections of PRP to the repair site at postoperative days 7 and 14. Early structural healing was assessed with MRI at 16 weeks, and cuff appearances were graded according to the Sugaya classification. Functional scores were recorded with the Oxford Shoulder Score; Quick Disability of the Arm, Shoulder and Hand; visual analog scale for pain; and Short Form-12 quality-of-life score both preoperatively and at postoperative weeks 6, 12, and 16; isokinetic strength and active range of motion were measured at 16 weeks.

RESULTS

PRP treatment did not improve early functional recovery, range of motion, or strength or influence pain scores at any time point after arthroscopic supraspinatus repair. There was no difference in structural integrity of the supraspinatus repair on MRI between the PRP group (0% full-thickness retear; 23% partial tear; 77% intact) and the control group (7% full-thickness retear; 23% partial tear; 70% intact) at 16 weeks postoperatively (P = .35).

CONCLUSION

After arthroscopic supraspinatus tendon repair, image-guided PRP treatment on 2 occasions does not improve early tendon-bone healing or functional recovery.

Clinical applications of platelet-rich plasma in patellar tendinopathy

Platelet-rich plasma (PRP), a blood derivative with high concentrations of platelets, has been found to have high levels of autologous growth factors (GFs), such as transforming growth factor-β (TGF-β), platelet-derived growth factor (PDGF), fibroblastic growth factor (FGF), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF). These GFs and other biological active proteins of PRP can promote tissue healing through the regulation of fibrosis and angiogenesis. Moreover, PRP is considered to be safe due to its autologous nature and long-term usage without any reported major complications. Therefore, PRP therapy could be an option in treating overused tendon damage such as chronic tendinopathy. Here, we present a systematic review highlighting the clinical effectiveness of PRP injection therapy in patellar tendinopathy, which is a major cause of athletes to retire from their respective careers.