Efficacy of a platelet-rich plasma injection for the treatment of proximal hamstring tendinopathy: A pilot study

Evidence-Based Clinical Practice Guidelines on Regenerative Medicine Treatment for Chronic Pain: A Consensus Report from a Multispecialty Working Group

Purpose

Injectable biologics have not only been described and developed to treat dermal wounds, cardiovascular disease, and cancer, but have also been reported to treat chronic pain conditions. Despite emerging evidence supporting regenerative medicine therapy for pain, many aspects remain controversial.

Methods

The American Society of Pain and Neuroscience (ASPN) identified the educational need for an evidence-based guideline on regenerative medicine therapy for chronic pain. The executive board nominated experts spanning multiple specialties including anesthesiology, physical medicine and rehabilitation, and sports medicine based on expertise, publications, research, and clinical practice. A steering committee selected preliminary questions, which were reviewed and refined. Evidence was appraised using the United States Preventive Services Task Force (USPSTF) criteria for evidence level and degree of recommendation. Using a modified Delphi approach, consensus points were distributed to all collaborators and each collaborator voted on each point. If collaborators provided a decision of "disagree" or "abstain", they were invited to provide a rationale in a non-blinded fashion to the committee chair, who incorporated the respective comments and distributed revised versions to the committee until consensus was achieved.

Results

Sixteen questions were selected for guideline development. Questions that were addressed included type of injectable biologics and mechanism, evidence in treating chronic pain indications (eg, tendinopathy, muscular pathology, osteoarthritis, intervertebral disc disease, neuropathic pain), role in surgical augmentation, dosing, comparative efficacy between injectable biologics, peri-procedural practices to optimize therapeutic response and quality of injectate, federal regulations, and complications with mitigating strategies.

Conclusion

In well-selected individuals with certain chronic pain indications, use of injectable biologics may provide superior analgesia, functionality, and/or quality of life compared to conventional medical management or placebo. Future high-quality randomized clinical trials are warranted with implementation of minimum reporting standards, standardization of preparation protocols, investigation of dose-response associations, and comparative analysis between different injectable biologics.

Non-surgical management of acute proximal hamstring avulsions can produce clinically acceptable results

PURPOSE

To evaluate the mid-term clinical outcomes for the non-surgical and surgical management of acute proximal hamstring avulsions.

METHODS

Sixty physically active individuals were offered surgical or non-surgical management for their proximal hamstring avulsion injuries. Distal retraction was defined as greater than 2 cm. Primary outcome measures were the Victorian Institute of sport assessment-proximal hamstring tendons (VISA-H) and functional assessment scale for acute hamstring injuries (FASH). Secondary outcome measures included palpable gap (cm), return to sport (RTS) and the ability to perform Nordic hamstring curls. Outcome variables were adjusted in regression models for gender, age, and treatment.

RESULTS

Thirty-one patients elected to undertake non-surgical management, and 29 chose surgery with a mean follow-up of 34.8 ± 8.7 and 34.9 ± 7.0 months, respectively. The mean VISA-H for the non-surgical and surgical groups were 87.3 ± 3.4 and 87.9 ± 4.1 (n.s.), respectively. The mean FASH for the non-surgical group was 89.3 ± 2.4 and 88 ± 3.6 for the surgical group (n.s.). This was consistent after adjusting for confounders. The mean gap for the non-surgical group was 4.5 ± 1.09 and 4.9 ± 1.19 cm for the surgical group (n.s.). No significant differences were found in the abilities to perform Nordic hamstring curls (n.s.). Both groups achieved comparable RTS rates (n.s.). On average, the non-surgical group achieved RTS at 5.5 ± 1.2 months post-injury, whereas the surgical group was at 5.7 ± 0.7 months (n.s.).

CONCLUSION

Physically active individuals with acute proximal hamstring avulsions and distal retraction of the tendon stump can be managed non-surgically, achieving similar functional levels and RTS compared to patients treated surgically.

LEVEL OF EVIDENCE

Level III.

Current and future advances in practice: tendinopathies of the hip

Tendinopathy describes persistent tendon pain and loss of function related to mechanical loading. Two common hip tendinopathies seen in practice are gluteal tendinopathy and proximal hamstring tendinopathy. Both conditions can be frustrating for patients and clinicians due to the delay in diagnosis, significant disability caused and lack of response to common treatments. Tendinopathy is a clinical diagnosis and can most often be made using findings from the patient interview and pain provocation tests, without the need for imaging. Specific education and progressive exercise offer a low-risk and effective option for gluteal tendinopathy and result in greater rates of treatment success than corticosteroid injection, both in the short term (8 weeks) and at 1 year. Proximal hamstring tendinopathy is a common, but less researched, and under-recognized cause of persistent ischial pain. As research on proximal hamstring tendinopathy is limited, this review summarizes the available evidence on diagnosis and treatment following similar principles to other well-researched tendinopathies.

Most Orthopaedic Platelet-Rich Plasma Investigations Don't Report Protocols and Composition: An Updated Systematic Review

PURPOSE

To systematically review the literature to assess the heterogeneity of platelet-rich plasma (PRP) preparation and composition reporting for the treatment of musculoskeletal/orthopaedic pathologies.

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify Level I and Level II studies from 2016 to 2022 that evaluated the use of PRP therapy for musculoskeletal pathologies. The search phrase used was "platelet-rich plasma clinical studies." Studies were assessed based on their reporting of the PRP preparation methods and reporting of PRP composition.

RESULTS

One hundred twenty-four studies (in 120 articles) met inclusion criteria for analysis. Of these studies, 15 (12.1%) provided comprehensive reporting, including a clear, well-described, and reproducible preparation protocol that future investigators can follow. Thirty-three studies (26.6%) quantitatively reported the final PRP product composition.

CONCLUSIONS

Among the studies using PRP for the treatment of musculoskeletal/orthopaedic pathologies, less than 20% provided a clear, well-described, and reproducible PRP preparation protocol, and only one-fourth of studies reported on the final PRP product composition.

CLINICAL RELEVANCE

A diverse current reporting of PRP composition between studies provides a high heterogeneity of the term "PRP," which becomes a limitation for a comparison of studies using PRP.

Hamstring Injury Treatments and Management in Athletes: A Systematic Review of the Current Literature

BACKGROUND

The field of sports medicine presents a varied landscape of research on hamstring injuries in athletes, characterized by inconclusive and sometimes conflicting findings on effective treatment and rehabilitation strategies. This discordance prompted the current systematic investigation.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for conducting the systematic review. Multiple international bibliometric databases (Scopus, PubMed, Web of Science, and Embase) were searched to identify studies evaluating any treatment option for the management of hamstring injuries in athletes. Eligible studies were appraised for quality using Joanna Briggs Institute and Risk of Bias 2 tools.

RESULTS

A total of 30 studies with 1,195 participants were included. Of the reviewed studies, treatments varied from aggressive rehabilitation, platelet-rich plasma (PRP) injections, manual techniques, various exercise protocols to modalities like high-power laser and nonsteroidal anti-inflammatory drugs. Evidence suggested benefits from treatments like extensive muscle lengthening during eccentric actions, progressive agility, and trunk stabilization. PRP injections produced mixed results regarding return to sport and reinjury rates. Stretching exercises, sometimes combined with cryotherapy, showed benefits.

CONCLUSION

Treatments for hamstring injuries exhibit varied efficacy. Although rest, ice, compression, and elevation remains essential for acute management, rehabilitation focusing on muscle strengthening and flexibility is crucial. The potential benefits of PRP injections, especially for chronic cases, require more conclusive research. A comprehensive approach, combining evidence-based practices and patient-centric factors, is vital for effective management and recovery.

LEVEL OF EVIDENCE

Level IV. See Instructions for Authors for a complete description of levels of evidence.

Angiogenesis and Tissue Repair Depend on Platelet Dosing and Bioformulation Strategies Following Orthobiological Platelet-Rich Plasma Procedures: A Narrative Review

Angiogenesis is the formation of new blood vessel from existing vessels and is a critical first step in tissue repair following chronic disturbances in healing and degenerative tissues. Chronic pathoanatomic tissues are characterized by a high number of inflammatory cells; an overexpression of inflammatory mediators; such as tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1); the presence of mast cells, T cells, reactive oxygen species, and matrix metalloproteinases; and a decreased angiogenic capacity. Multiple studies have demonstrated that autologous orthobiological cellular preparations (e.g., platelet-rich plasma (PRP)) improve tissue repair and regenerate tissues. There are many PRP devices on the market. Unfortunately, they differ greatly in platelet numbers, cellular composition, and bioformulation. PRP is a platelet concentrate consisting of a high concentration of platelets, with or without certain leukocytes, platelet-derived growth factors (PGFs), cytokines, molecules, and signaling cells. Several PRP products have immunomodulatory capacities that can influence resident cells in a diseased microenvironment, inducing tissue repair or regeneration. Generally, PRP is a blood-derived product, regardless of its platelet number and bioformulation, and the literature indicates both positive and negative patient treatment outcomes. Strangely, the literature does not designate specific PRP preparation qualifications that can potentially contribute to tissue repair. Moreover, the literature scarcely addresses the impact of platelets and leukocytes in PRP on (neo)angiogenesis, other than a general one-size-fits-all statement that "PRP has angiogenic capabilities". Here, we review the cellular composition of all PRP constituents, including leukocytes, and describe the importance of platelet dosing and bioformulation strategies in orthobiological applications to initiate angiogenic pathways that re-establish microvasculature networks, facilitating the supply of oxygen and nutrients to impaired tissues.

A pilot randomised trial comparing individualised physiotherapy versus shockwave therapy for proximal hamstring tendinopathy: a protocol

PURPOSE

Proximal hamstring tendinopathy (PHT) presents as localised lower buttock pain with tasks such as squatting and sitting. It is a condition that occurs at all ages and levels of sporting participation and can cause disability with sport, work, and activities of daily living. This paper details a pilot trial protocol for investigating the effectiveness of individualised physiotherapy compared to extracorporeal shockwave therapy (ESWT) on pain and strength in people with PHT.

METHODS

The study is an assessor-blinded, pilot randomised controlled trial (RCT). One hundred participants with PHT will be recruited from the local community and sporting clubs. Participants will be randomised to receive six sessions of either individualised physiotherapy or ESWT, with both groups also receiving standardised education and advice. Primary outcomes will be global rating of change on a 7-point Likert scale, and the Victorian Institute of Sport-Hamstring (VISA-H) scale, measured at 0, 4, 12, 26 and 52 weeks. Secondary outcomes will include sitting tolerance, the modified Physical Activity Level Scale, eccentric hamstring strength, modified Tampa scale for kinesiophobia, the Örebro Musculoskeletal Pain Screening Questionnaire Short Form (ÖMPSQ-SF), Numerical Pain Rating Scale (NPRS) for average and worst pain, participant adherence, the Pain Catastrophizing scale, satisfaction scores, and quality of life. Data will be analysed on an intention to treat basis, with between-group effects estimated using linear mixed models for continuous data and Mann Whitney U tests for ordinal data.

CONCLUSIONS

This pilot RCT will compare individualised physiotherapy versus ESWT for PHT. The trial will determine feasibility and estimated treatment effects to inform a definitive trial in the future.

TRIAL REGISTRATION

The trial has been prospectively registered with the Australia & New Zealand Clinical Trials Registry (ACTRN12621000846820), registered 1 July 2021, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373085.

Lower extremity ultrasound-guided interventions: tendon, ligament, and plantar fascia

Lower extremity tendinopathy and soft tissue injury are common clinical problems that can cause significant disability. Ultrasound-guided minimally invasive treatments using orthobiologics and image-guided percutaneous treatments continue to gain relevance with an ever-growing body of literature. We review the indications, technique, risks, and benefits according to the literature of common ultrasound-guided interventions utilized in the lower extremities.

Female Athlete Hip Injuries: A Narrative Review

OBJECTIVE

In this narrative review, we highlight sex-specific anatomic and biomechanical features of the hip region in female athletes, as well as the potential impact of these characteristics on observed disparities in both intra-articular and extra-articular injury patterns between female and male athletes. It is our goal to broaden the scope of knowledge related to hip pathology in active female athletes among sports medicine providers with the hope of better optimizing sport participation and performance in female athletes.

DATA SOURCES

A literature review was conducted using PubMed database and Google Scholar search engine. Search terms included sport, female, athlete, sex differences, injury, hip, and all diagnoses discussed in this review. Cross-reference of these articles identified additional resources.

MAIN RESULTS

Sex-specific differences in both static design and dynamic function contribute to disparities in hip injury patterns between female and male athletes. Intra-articular injuries, including labral and ligamentum teres pathology, as well as extra-articular injuries, including iliopsoas tendon dysfunction, gluteal and proximal hamstring tendinopathy, ischiofemoral impingement, bone stress injuries, and certain nerve entrapment syndromes, seem to affect female athletes more commonly than male counterparts.

CONCLUSIONS

Given unique anatomic and functional considerations, the growing population of female athletes worldwide warrants specialized care and consideration. Potential predisposition to specific hip injuries should be taken into consideration during diagnostic evaluation of hip pain in the female athlete.

The use of biologics to improve patient-reported outcomes in hip preservation

Despite lack of clear understanding, the use of biologic treatment methods has increased in the United States. Therapeutic methods, including platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC) and hyaluronic acid (HA) among other biologics, are commonly associated with relief of pain in a number of different orthopedic conditions. Within the past two decades, hip preservationists have investigated the roles of these biologic treatments in both non-operative and surgical management of common hip conditions. The purpose is to review the published literature surrounding the application and efficacy of biologics, most notably PRP, BMAC and HA, in the clinical management of hip conditions. The hip conditions examined in this review include hip osteoarthritis, femoroacetabular impingement syndrome and associated labral tear pathology, avascular necrosis of the femoral head and gluteal/hamstring tendinopathy. While our review of the literature suggests that there is support for the implementation of biologics to relieve pain and improve function for hip conditions. Through further research efforts, it is important to stay updated with the clinical efficacy of biologics in hip preservation.

Clinical indications for image-guided interventional procedures in the musculoskeletal system: a Delphi-based consensus paper from the European Society of Musculoskeletal Radiology (ESSR)-part IV, hip

Objectives

Image-guided musculoskeletal interventional procedures around the hip are widely used in daily clinical practice. The need for clarity concerning the actual added value of imaging guidance and types of medications to be offered led the Ultrasound and the Interventional Subcommittees of the European Society of Musculoskeletal Radiology (ESSR) to promote, with the support of its Research Committee, a collaborative project to review the published literature on image-guided musculoskeletal interventional procedures in the lower limb in order to derive a list of clinical indications.

Methods

In this article, we report the results of a Delphi-based consensus of 53 experts who reviewed the published literature for evidence on image-guided interventional procedures offered in the joint and soft tissues around the hip in order of their clinical indications.

Results

Ten statements concerning image-guided treatment procedures around the hip have been collected by the panel of ESSR experts.

Conclusions

This work highlighted that there is still low evidence in the existing literature on some of these interventional procedures. Further large prospective randomized trials are essential to better confirm the benefits and objectively clarify the role of imaging to guide musculoskeletal interventional procedures around the hip.

Key Points

• Expert consensus produced a list of 10 evidence-based statements on clinical indications of image-guided interventional procedures around the hip.

• The highest level of evidence was only reached for one statement.

• Strong consensus was obtained for all statements.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-07997-5.

Proximal Hamstring Tendinopathy: A Systematic Review of Interventions

BACKGROUND

Proximal hamstring tendinopathy affects athletic and non-athletic populations and is associated with longstanding buttock pain. The condition is common in track and field, long distance running and field-based sports. Management options need to be evaluated to direct appropriate clinical management.

PURPOSE/HYPOTHESIS

To evaluate surgical and non-surgical interventions used in managing proximal hamstring tendinopathy.

STUDY DESIGN

Systematic review.

METHODS

Electronic databases were searched to January 2019. Studies (all designs) investigating interventions for people with proximal hamstring tendinopathy were eligible. Outcomes included symptoms, physical function, quality of life and adverse events. Studies were screened for risk of bias. Reporting quality was assessed using the Cochrane Risk of Bias Tool (Randomized Controlled Trials [RCT]) and the Joanna Briggs Institute Checklist (Case Series). Effect sizes (Standard mean difference or Standard paired difference) of 0.2, 0.5 and 0.8 were considered as small, medium and large respectively. Overall quality of evidence was rated according to GRADE guidelines.

RESULTS

Twelve studies (2 RCTs and 10 case series) were included (n=424; males 229). RCTs examined the following interventions: platelet-rich plasma injection (n=1), autologous whole-blood injection (n=1), shockwave therapy (n=1) and multi-modal intervention (n=1). Case series included evaluation of the following interventions: platelet-rich plasma injection (n=3), surgery (n=4), corticosteroid injection (n=2), multi-modal intervention + platelet-rich plasma injection (n=1). Very low-level evidence found shockwave therapy was more effective than a multi-modal intervention, by a large effect on improving symptoms (-3.22 SMD; 95% CI -4.28, -2.16) and physical function (-2.42 SMD; 95% CI-3.33, -1.50) in the long-term. There was very low-level evidence of no difference between autologous whole-blood injection and platelet-rich plasma injection on physical function (0.17 SMD; 95% CI -0.86, 1.21) to (0.24 SMD; 95% CI -0.76, 1.24) and quality of life (-0.04 SMD; 95%CI -1.05, 0.97) in the medium-term. There was very low-quality evidence that surgery resulted in a large reduction in symptoms (-1.89 SPD; 95% CI -2.36, -1.41) to (-6.02 SPD; 95% CI -8.10, -3.94) and physical function (-4.08 SPD; 95%CI -5.53, -2.63) in the long-term.

CONCLUSIONS

There is insufficient evidence to recommend any one intervention over another. A pragmatic approach would be to initially trial approaches proven successful in other tendinopathies.

LEVEL OF EVIDENCE

Level 2a.

Platelet-Rich Plasma Injection for the Treatment of Hamstring Injuries: A Systematic Review and Meta-analysis With Best-Worst Case Analysis

BACKGROUND

Hamstring injuries are common and account for considerable time lost to play in athletes. Platelet-rich plasma has potential as a means to accelerate healing of these injuries.

PURPOSE

(1) To present the evidence of platelet-rich plasma injection in the treatment of hamstring injuries, (2) evaluate the "best-case scenario" in dichotomous outcomes, and (3) evaluate the "worst-case scenario" in dichotomous outcomes.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Two authors systematically reviewed the PubMed, Embase, and Cochrane Library databases according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, with any discrepancies resolved by mutual consensus. The level of evidence was assessed per the criteria of the Oxford Centre for Evidence-Based Medicine and the quality of evidence by the Coleman Methodology Score. Meta-analysis by fixed effects models was used if heterogeneity was low (I² < 25%) and random effects models if heterogeneity was moderate to high (I²≥ 25%). P values <.05 were considered statistically significant.

RESULTS

A total of 10 studies were included with 207 hamstring injuries in the platelet-rich plasma group and 149 in the control group. Random-effects model for mean time to return to play that compared platelet-rich plasma + physical therapy to physical therapy alone non-significantly favored platelet-rich plasma + physical therapy (mean difference, -5.67 days). The fixed effects model for reinjury rates, which also compared platelet-rich plasma + physical therapy with physical therapy alone nonsignificantly favored platelet-rich plasma + physical therapy (risk ratio, 0.88). The best-case scenario fixed effects model for reinjury rates nonsignificantly favored platelet-rich plasma + physical therapy (risk ratio, 0.82). The worst-case scenario fixed effects model for reinjury rates nonsignificantly favored physical therapy alone (risk ratio, 1.13). The mean ± SD complication rate for either postinjection discomfort, pain, or sciatic nerve irritation was 5.2% ± 2.9% (range, 2.7% to 9.1%).

CONCLUSION

There has been statistically nonsignificant evidence to suggest that PRP injection ± PT reduced mean time to RTP or reinjury rates compared to no treatment or PT alone for hamstring injuries in a short-term follow-up. The complication profiles were favorable. Further studies of high quality and large cohorts are needed to better support or disprove the consensus of the systematic review and meta-analysis.

THE MANAGEMENT OF PROXIMAL HAMSTRING TENDINOPATHY IN A COMPETITIVE POWERLIFTER WITH HEAVY SLOW RESISTANCE TRAINING - A CASE REPORT

Background and Purpose

Proximal hamstring tendinopathy is a chronic, overuse condition that commonly develops in athletes. Eccentric exercise has been widely accepted in the clinic as the treatment of choice for the management of tendinopathies. However, this form of treatment has seldom been compared to other forms of load-based management for hamstring tendinopathies. Heavy slow resistance training, which consists of both concentric and eccentric phases, increases the loading time experienced by the tendon compared to eccentric only exercises. Heavy slow resistance training has achieved positive clinical results in the management of Achilles and patellar tendinopathy.

Purpose

The purpose of this case report is to describe the outcomes of a powerlifter with proximal hamstring tendinopathy who responded favorably to a heavy slow resistance biased rehabilitation program after traditional, conservative management failed to alleviate symptoms.

Case Description

A 31-year-old male competitive powerlifter was seen in physical therapy for the management of proximal hamstring tendinopathy. The subject had experienced long duration pain localized at the ischial tuberosity combined with hip weakness that limited his ability to lift weigtht and sit for longer than 30 minutes. Treatment included a 12-week heavy slow resistance program with the focus of increasing load intensity.

Outcomes

Numeric pain-rating scale was assessed at baseline, after a 12-week heavy slow resistance protocol, and 12 months post protocol. Within four weeks of starting the heavy slow resistance program, the subject noted a meaningful decrease in pain. The subject experienced clinically important improvements in numeric pain-rating scale immediately after the protocol and these improvements remained 12 months after completing the protocol. The subject was able to return to competitive powerlifting after the 12-week program.

Discussion

A meaningful change in pain occurred within four weeks of starting the program and continued improvement throughout the remainder of the 12 weeks with outcomes maintained 12 months after completing the program suggests that increasing the loading strategy with a heavy slow resistance program was helpful for this subject.

Level of Evidence

4.

Platelet-rich plasma for treatment of chronic proximal hamstring tendinopathy

Aim: To determine whether platelet-rich plasma (PRP) can successfully treat symptoms associated with proximal hamstring tendinopathy. Materials & methods: Charts were retrospectively reviewed of patients with a diagnosis of chronic proximal hamstring tendinopathy who underwent an ultrasound-guided leukocyte-rich PRP injection to assess reported outcomes at baseline and final follow-up post-intervention. Results: In 22 patients with a mean age of 48.7 years and mean symptom duration of 26.5 months, mean Numeric Pain Rating Scale and Victorian Institute of Sport Assessment Scale for Proximal Hamstring Tendinopathy subscores demonstrated statistically significant improvements (p < 0.05) at a mean of 7.91 months follow-up. Sixty-eight percent of patients demonstrated ≥50% reduction of pain. Conclusion: Pain and functional outcomes improved following injection of PRP.

Post-Procedure Protocols Following Platelet-Rich Plasma Injections for Tendinopathy: A Systematic Review

OBJECTIVE

Platelet-rich plasma (PRP) has been increasingly studied as a treatment for tendinopathy. Many factors may influence outcomes after PRP, including different protocols following administration. It was hypothesized that there would be heterogeneity in post-PRP protocols.

LITERATURE SURVEY

A systematized review of the literature on post-PRP protocols for tendinopathy was conducted using an electronic search of MEDLINE and Embase databases through September 2018.

METHODOLOGY

After duplicates were removed, English language articles involving adult patients who received PRP for tendinopathy were reviewed. Exclusion criteria included studies with fewer than 10 patients, PRP used to treat pathology other than tendinopathy, multiple protocols in one study, and surgical settings. Protocol specifics were extracted including nonsteroidal anti-inflammatory drugs (NSAID) restrictions before and after injection, postinjection restrictions on movement and weight bearing, use of orthoses, activity modifications, and postinjection rehabilitation protocols. Given limitations in the data, a meta-analysis was not performed.

SYNTHESIS

Eighty-four studies met inclusion criteria. Following PRP injection, weight-bearing restrictions were mentioned rarely (12% of protocols). Orthosis use was uncommon overall (18%) but more common in Achilles tendinopathy protocols (53%). The majority of protocols instituted a period of stretching (51%) and strengthening (54%). Stretching programs generally began 2-7 days following injection, and strengthening programs began within 2-3 weeks. Preinjection NSAID restriction was reported rarely (20%), whereas postinjection NSAID restriction was more common (56%), with a typical restriction of greater than 2 weeks (38%). Return to play or full activity was reported in 42% of protocols, most commonly at 4-6 weeks following injection.

CONCLUSION

Although the clinical effectiveness of PRP remains controversial, even less is known about the effect of post-PRP protocols, which may affect the outcomes attributed to PRP itself. No studies directly compare post-PRP protocols, and the protocols studied demonstrate substantial heterogeneity. Some consensus regarding post-PRP protocols exists, although the rationale for these recommendations is limited.