Reference
Sharma R, Chaudhary NK, Karki M, et al. Effect of platelet-rich plasma versus steroid injection in plantar fasciitis: a randomized clinical trial. BMC Musculoskelet Disord. 2023;24(1):172.
Study Objective
To compare the effectiveness of platelet-rich plasma (PRP) injection with steroid injection (SI) in the treatment of plantar fasciitis (PF)
Design
A single-center, hospital-based, open-label, parallel-group, randomized clinical trial
Participants
The study included 90 randomly selected participants (aged 18–60 years; 76% female) with a diagnosis of PF persisting for 6 weeks or longer despite treatments of physiotherapy, splints, and nonsteroidal anti-inflammatory drugs (NSAIDS). All participants were mentally fit and outpatients of the facility.
Three participants were lost to follow-up in the steroid group, resulting in end analyses of 42 in the steroid group and 45 in the PRP group.
Investigators excluded patients if they had undergone previous surgery; had foot pathology, existing trauma, or lumbar radiculopathy; were taking aspirin treatment; or had low platelet counts, bleeding disorders, or any systemic diseases (eg, diabetes and rheumatoid arthritis).
Interventions
Investigators randomized participants to receive either PRP therapy or steroid injections.
Both injection forms were administered into the tender point of the medial calcaneal tuberosity using sterile technique. The midline and endline data were recorded at 3 and 6 months, respectively.
The steroid group was injected with 2 mL of Depo-Medrol 80 mg (methylprednisolone) along with 1 mL lignocaine (0.25%) in a 5-cc syringe.
PRP collection consisted of drawing 30 mL of blood into an acid citrate dextrose tube, which was then centrifuged first at a soft spin of 2,000 rpm (digital centrifuge machine: Remi, R-8C Plus). Of the 3 layers produced, the supernatant and plasma buff coat were once again centrifuged at a hard spin of 3,000 rpm. The upper 2/3 layer of platelet-poor plasma was discarded, and the lower 1/3 layer of concentrated platelet plasma superficial buffy coat was injected.
Investigators advised participants to abstain from any vigorous activity with the affected foot for at least 2 days after the injection and then gradually return to their regular activities.
Study Parameters Assessed
The 3 parameters assessed included The American Orthopaedic Foot & Ankle Society (AOFAS) score, the Visual Analog Scale (VAS), and the plantar fascia thickness via ultrasound measurement. The AOFAS and VAS were measured before intervention (baseline), after intervention at 3 months (midline), and at 6 months (endline), while plantar fascia thickness was measured at baseline and at 6 months.
Primary Outcome
The primary outcomes assessed were functional mobility (AOFAS score) and pain (VAS) of the participants; the secondary outcome measured included plantar fascia thickness.
Key Findings
Key primary findings in this study included the following: At baseline, the mean ±VAS scores were not significantly different between the 2 groups: 5.22 ± 1.34 in the PRP group and 4.77 ± 0.95 in the SI group, with a group difference of 0.44 (95% CI: –0.04 to 0.93; P=0.073).
In the 3-month follow-up, pain scores were 4.22 ± 1.04 and 3.14 ± 0.81 in the PRP and SI groups, respectively, with a group difference of 1.07 (95% CI: 0.67 to 1.47; P<0.001). At the 6-month follow-up, the PRP pain score was 1.97 ± 1.13, and the SI pain score was 2.71 ± 0.94, indicating a significant difference of –0.73 (95% CI: –1.18 to –0.028; P=0.001).
Functional mobility differed at baseline between the 2 groups, as measured with the AOFAS scores: 52.53 ± 14.87 in the PRP group and 58.14 ± 11.47 in the SI group, with a difference of –5.60 (95% CI: –11.30 to 0.08; P=0.005). In the 3-month follow-up, AOFAS score improved to 63.80 ± 12.04 in the PRP group and 75.76 ± 7.18 in the SI group, with a group difference of –11.96 (95% CI: –16.22 to –7.69; P<0.001). At 6 months, there was another significant difference in the AOFAS score in the PRP group vs the SI group, with an increase in functional mobility in the PRP group of 86.04 ± 7.45 and 81.23 ± 9.60 in the SI group, with a group difference of 4.80 (95% CI: 1.15 to 8.45; P=0.011).
Secondary outcomes measured the difference in plantar fascia thickness between the 2 groups at baseline (5.56 ± 0.95 mm vs 5.69 ± 0.88 mm in the PRP and SI groups, respectively, with a nonstatistical difference of –0.12 (95% CI: –1.44 to –0.65; P=0.507). This decreased to 3.53 ± 0.81 mm in the PRP group and 4.58 ± 1.02 mm in the SI group at the 6-month follow-up (difference of –1.04; 95% CI: –1.44 to –0.65; P<0.001).
Transparency
The authors of this study declared no competing interests. The research was funded by the Provincial Research Grant (116/2021) under the Nepal Health Research Council (NHRC), which also approved the ethical review (3322, 06/06/2021). The study methods were also approved by the Ethical Review Board of the NHRC (3322, approved 06/06/2021).
Practice Implications & Limitations
This study contributes to the growing number of studies indicating the use of PRP for musculoskeletal conditions.
The use of PRP in lieu of steroids should be considered not only for its effectiveness in pain relief but, more importantly, for its ability to heal the tissues through the release of growth factors (GFs). The majority of GFs (70%) are released between 10 minutes and 1 hour after injection with PRP, stimulating the synthesis and secretion of further growth factors for approximately 8 days, with complete effects at 6 to 8 weeks.
On the other hand, steroids can interfere with the inflammatory and immune cascade, but these effects are limited in duration. Further, steroids do not contribute to the health of the tissue or any direct regenerative processes.1
Chronic plantar fasciitis is a very common condition that can arise when the weight and stress exerted on the plantar arch is beyond its capability to withstand.
Symptoms and characteristics that define plantar fasciitis include: stiffness in the heel that is worse first thing in the morning, sharp pain in the heel, aching arches, swelling and redness, and pain that is usually better with rest or fascial stretching or ice.
Likelihood of occurrence increases with anatomical, biomechanical, or environmental stressors including obesity or sudden weight gain (as from pregnancy, for example), pes planus (flat feet), pes cavus (high arch), shortened Achilles tendon, overpronation, weak intrinsic or plantar foot muscles of the foot and limited ankle dorsiflexion, anomalies of alignment, deconditioning with new activity undertaken, impact activity on hard surfaces, walking barefoot or wearing poor footwear, prolonged weight bearing such as from standing, and a lack of stretching.2
In terms of diagnosis of plantar fasciitis, it is important to consider other factors as causative since not all heel pain is, in fact, plantar fasciitis. Other causes of heel pain include neurological conditions and neuropathy, fractures, soft-tissue changes, contusions, Achilles tendinitis, retrocalcaneal bursitis, and tibial tendonitis. Although these latter conditions may still lead to the use of PRP as treatment, they may alter the choice of injection points.2
In a study of 220 participants, researchers found that waist girth, ankle plantar flexor strength, multisite pain, and exaggerated pain were not foot-related but systemic or centrally caused. This is important to consider when evaluating for appropriate treatment protocols in practice.3 Acute and physical care provides relief, but as we were taught in naturopathic training, the “site of pain is not always the site of injury.” Therefore, it may be prudent to evaluate with ultrasound the exact nature of the tissue injury before instituting second-line therapies for plantar fasciitis, and if targeted therapies do not provide lasting relief, to conduct more systemic analysis.
It is important to consider other factors as causative since not all heel pain is, in fact, plantar fasciitis.
Before beginning a therapy, the Therapeutic Order should be considered so that the gentlest interventions are done first. Lifestyle modifications will make a difference in the immediate and long-term strategy of care. Initial changes that patients can put into place prior to the initiation of any therapy include proper shoe fit with appropriate arch support and managing provocation factors like walking barefoot, prolonged standing, and running, the latter of which requires more frequent shoe changes due to increased shoe wear and tear. Cross-training is another strategy to minimize fascial degradation, along with stretching exercises specific to the fascia.
A 2014 systematic review in the Journal of Orthopaedic & Sport Physical Therapy (JOSPT) noted that plantar fasciitis will usually resolve within 8 to 10 months without therapy. The guidelines further state that in addition to targeted exercises for muscles that control pronation and lessen weightbearing activities, physiotherapy can include stretching, taping, foot orthoses, night splints, electrotherapy, phonophoresis with ketoprofen gel ultrasound, footwear assessment, and the implementation of nutritional therapies.4
Nutritional therapy may prevent recurrence of fasciitis since higher BMI may be a risk factor.4 If celiac disease is present or undiagnosed, a gluten-free diet is warranted, as PF does present in approximately 12% of celiac cases.5
Plantar fasciitis primarily affects 2 tissues: the sheath and core stem cells, with changes in collagen I and IV tissues in different ways. To better understand the roles of connective tissue in plantar fasciitis, a study by Zhang et al helped practitioners to understand the ‘-itis’ part of PF at a cellular and mechanobiological level. In their analysis, Zhang et al explained that type 1 collagen in the core stem cells (PF-C) plays a role in ligament tissue, and high levels of collagen IV in the sheaths (PF-S) suggests its role in basement membrane integrity. They also found that the amount of mechanical load on the tissue made a difference to development of PF. Increased loads increased angiogenesis and neovascularization, both of which are suggested factors involved in chronic tendon pain, through a mechanism involving induction of CD105. This suggests that mechanical overload with subsequent neovascularization is a factor in the induction of PF inflammation. A moderate load did not produce the same effects on CD105 induction and, therefore, did not promote neovascularization formation. However, both loads did increase collagen IV in the sheath cells and thereby thickened the fascia, which was interpreted as a “mechanical adaptive response."6
Zhang’s study helps to further our understanding of the aetiologies, down to the roles of stem cells and collagen in the development of plantar fasciitis, potentially furthering the nuances of the physiological mechanisms by which PRP works at the cellular and tissue level. This may be something to consider as well when we take into account the pathological development of other conditions that relate to collagen I and IV and vascularization.
While this PRP study evaluated the difference between steroid injection versus PRP, it is also important to consider whether other therapies such as prolotherapy and less-invasive therapies—such as microcurrent and low-level light laser therapy, herbs, bone morphogenic proteins, hydrotherapy, myofascial release techniques, extracorporeal shock wave therapy (ESWT), acupuncture points (PC-7, located at the wrist crease),7 and homeopathy—may be useful in isolation or in combination with PRP to enhance tissue healing.
In practice, prolotherapy is often a modality that healthcare providers would generally consider prior to PRP, as it, too, helps the tissue to heal through provocation of an inflammatory healing cascade, and it provides long-term pain relief when aggravating factors have been addressed.
A 2021 randomized, double-blinded, randomized, placebo-controlled study in India examined the effects of individualized homeopathic medicines vs placebo in the treatment of plantar fasciitis over a 3-month period.8 Foot function indices (FFI) significantly changed in the homeopathy group, with the most drastic reductions occurring in the first month. The most common remedies prescribed were Natrum muriaticum, Rhus tox, and Ruta graveolens.
Other therapies to consider that may enhance, or even make unnecessary, the use of PRP treatment include electroacupuncture or dry-needle acupuncture, both at distal points (including PC-7, a common heel pain point located at the midline point on the palmar wrist crease) and more-local focal points.7 A randomized, controlled trial evaluating sham vs targeted dry needling did find favorable results with targeted dry needling, but the difference was not large enough to meet predefined criteria. The real dry needling group did experience increased transitory adverse events (32% of participants) over the sham group as well.9
Limitations of the current study under review include the fact that the participants were seen in a specialized orthopedic hospital, only after having undergone treatment in another center. Similarly, a multivariate analysis could not be applied without any confounders of the PF, and no anthropometric measurements of body mass were assessed. Investigators did not assess plantar thickness at 3 months due to cost, and data collection occurred during the Covid-19 pandemic (August 2020–March 2022), further impacted data collection.
