Introduction

Plantar fasciitis (PF) is one of the common causes of heel pain, and it manifests as pain originating from the insertion of plantar fascia near the medial calcaneal tubercle and it is worse at the first step in the morning.¹ The peak incidence of heel pain occurs between 40 and 60 years of age and it is a particularly a common problem in older athletes, runners, military recruits, and trades people.^2,3 Plantar fasciitis affects both sedentary and physically active individuals like athletic and military personnel and it is believed to arise from chronic overload, alignment or weakness issues either from lifestyle or exercise. The etiology is poorly understood and is unknown in nearly 85% of cases.⁴

The pathophysiology remains poorly understood, but appears similar to Achilles tendinopathy with microscopic degenerative injury and local disruption of the collagen matrix and microtears rather than a failed healing response.⁵ The presence of erratic blood flow with zones of hypovascularization and hypervascularization also plays a role in the disease process.^6,7 Clinical findings of chronic plantar fasciitis include local tenderness and associated stiffness due to soft tissue tightness and contracture with common patient complaints of morning pain and heel discomfort with initiation of ambulation.⁸

There are a plethora of treatment options, none of these are universally reliable or acceptable. Conservative therapies are usually the first line of treatment that includes ice, rest and avoidance of potentially strenuous activities, physical therapies, orthotics, arch supports, tapping and splinting. Other modalities include use of NSAIDS, ultrasonic Shockwave therapy, and, in the recalcitrant cases, surgery.

Corticosteroid injection is the mainstay of early treatment. However, conflicting evidence exists to support the use of steroid injection. Platelet rich plasma therapy is a revolutionary novel modality that relieves pain by stimulating long lasting healing of musculoskeletal conditions.^9-11 This clinical study was undertaken in patients of chronic planter fasciitis, to evaluate and compare the effectiveness of single injection of autologous platelet rich plasma and steroid injections.

Methods

The study was designed as a single centre prospective controlled randomized research. The present research was conducted in the Department of Orthopaedics, KBN Teaching and General Hospital, Kalaburagi, Karnataka, India from August 2016 to July 2018. Sixty patients having clinically diagnosed chronic unilateral plantar fasciitis who had failed to show any response following extensive traditional non-operative management were randomized into 2 groups for prospective treatment and evaluation.

Inclusion criteria consisted of patients > 18 years, both male and female with clinically diagnosed PF. Patients should have symptoms for a minimum period of three months and should have undergone conservative treatment during that period. 

Exclusion criteria consisted patients younger than 18 years, Plantar fasciitis less than 3 month duration, patients without any trial of conservative treatment, patient with neuropathic symptoms, clotting disorder or on anticoagulation therapy.

Group 1 received a single injection of 40 mg Triamcinolone (1 ml of 40 mg Triamcinolone with1 mL of 2% lidocaine) and group 2 a single injection of 2ml autologous PRP.

Preparation of PRP

The preparation of PRP is undertaken during the actual procedure and it takes about 20 minutes. Under aseptic precautions10 ml blood is withdrawn from antecubital vein in a 20ml sterile EDTAcoated sterile disposable test tube. This test tube is centrifuged at 22-24degree room temperature at 1500rpm/min for 15 minutes.

Following centrifugation, the blood sample is separated in different blood fractions (from bottom to top of the tube): lowest or red cells and granulocytes; middle or whitish opaque layer of buffy coat which contains osteoprogenitor cells, mononuclear cells and some platelets and the top one is yellowish transparent layer and contains plasma and platelets. This top layer is divided in two zones; upper platelet poor plasma (PPP) and lower platelet rich plasma (PRP) (Fig, 1). PPP layer is discarded with the help of a long bore sterile micropipette and around 2ml of PRP is collected and is ready to use.

 Technique

Under aseptic precautions, thoroughly paint the pathological site with povidone iodine and spirit, and identify the point of maximum tenderness.  2 % lidocaine (Xylocaine) 2-3mL of local anesthesthetic is delivered to the point  of maximum tenderness. Dry needling, also called peppering, is used to locally ‘‘injure’’ the soft tissue to excite the inflammatory response. After contacting the hard bony end, the needle is gently partially withdrawn and then advanced in a fan-like wheal, peppering the area 7 to 10 times; simultaneously injecting 0.20.3 ml of either PRP (2ml) or steroid (1 ml of 40 mg Triamcinolone with 1 mL of 2% lidocaine)

Post injection follow up

All patients were advised to refrain from vigorous/ sportive activities for at-least 3days post-procedure. Broad spectrum oral antibiotic and NSAIDs for three days are prescribed to the patients.

The outcomes in both groups are then evaluated and compared using visual analogue scale (VAS) and  Foot and Ankle Ability Measure (FAAM) scale at 1 month, 2 months, 3 months and 6 months post-injection.

Statistical analysis

The data are presented as mean ±SD. All calculations and statistics are performed with Statistical Package of Social Science (SPSS 20) Software. A “p-value” of less than 0.05 (p-<0.05) was regarded as significant.

Results 

The steroid group included 13 males and 17 females with an average age of 38 (range, 19 to 59) years. Symptoms averaged 5.4 (range, 4 to 24) months in duration prior to treatment.

The PRP group had 12 males and 18 females with an average age of 41 (range, 24 to 57) years. They averaged 5.7 (range, 4 to 26) months of symptoms prior to treatment.

All patients completed the follow-ups. The average follow up duration was about 6 months. There was a pronounced female preponderance (60%) mostly house wives (51%). Among males incidence of signs of CPF in groups of heavy workers was significantly higher and had greater disease severity than sedentary group.  Both the groups treated with PRP and with corticosteroid injections showed improvements in pain scores from the base line parameters at the end of 3 months follow up (p<0.05); the corticosteroid group had significant improvement at end of 3 months follow up (p<0.05). However, at 6month PRP group showed a significant (8.56±0.72 to 1.48±0.69) (p<0.05) benefit compared with the corticosteroid group for the pain component (Table 1). The FAAM scores-although better than baseline for both treatment groupsthe patients treated with PRP injection showed statistically significant improvement (30.30±6.10 to 84.1±5.66) (p<0.05) at six month of follow up (Table 2).  No complications were noted. Pain at the injection site was described by 90% of the patients, with no significant difference noted between the groups. This pain was attributed to the peppering maneuver before injection. The pain typically lasted not more than two days.

Discussion

Although the most common cause of heel pain is plantar fasciitis, the etiology and treatment are still not fully understood. There are no definite combinations of clinical, biomechanical, or training variables, or causative factors in the development of CPF have been found.¹² Steroid injections are considered as one of the treatment modalities. Unfortunately it has short term results and is associated with complications.¹⁴  It is widely believed that plantar fasciitis results from repeated micro-trauma from overuse, which results in micro-tears of the tissue substance until a macro injury occurs.¹³

Recently, regenerative medicine therapies such as  platelet-rich plasma have been used as an alternative therapy for CPF. It has shown relief from pain and improved function scores. In our singleblinded, prospective, randomized, longitudinal case series, the use of local PRP injection proved more successful than cortisone injection in the long term management of severe chronic plantar fasciitis in cases where prolonged traditional nonoperative treatment had failed. The likely mechanism of this effect is the release of growth factors and chemoattractants from the highly concentrated platelets in the plantar fascial injury zone.^15-20 These platelet nests may act as rally points for the local recruitment of macrophages and fibroblasts to gradually repair the damaged collagen of the tendon following platelet activation. This can lead to modulation of angiogenesis and local blood flow to assist correction of a failed healing response.^21,22 Collagen processing is improved with the in-migration of fibroblasts.^23,24 The finding that the majority of improvement seen in our patients occurred in the first month following the PRP injection suggests an early antiinflammatory effect possibly due to the inhibition of cyclo-oxygenase-2 (COX-2) enzymes by the cytokines in PRP (25, 26). The long-term durability of clinical success in the PRP group in this 2-year study may be the result of improved collagen upregulation and neovascularization.

In contrast to the encouraging results demonstrated in the PRP group in this study. The long-term results in steroid group were disappointing. Although initial results at 1,2 and 3 months postinjection were encouraging, subsequent clinical scoring at 6 months quickly degraded(short term effective). With the number of subjects available in this study, no significant difference was noted between the pretreatment and post-treatment results in the cortisone group after 6 months. PRP is as effective as corticosteroid injection at achieving symptom relief initially, for the treatment of plantar fasciitis. Unlike steroid, its effect does not wear off with time (long term effective). At 6months follow up, PRP was significantly associated with improved pain and function scores when compared with corticosteroid injections. Adverse effects were minimal, with both groups reporting self limited post injection pain.

The critical analysis of current research showed that PRP injection appears to have slower onset of action than steroid but it is much safer and longer acting as also supported by literature. The present study clearly demonstrate PRP injection to be an effective and well tolerated alternative to corticosteroid injection in the management of patients with chronic plantar fasciitis who have failed to respond to traditional non-operative treatment, with an added advantage of its biological nature of therapy and better patient compliance. Furthermore, PRP also possesses antimicrobial property which contributes to prevention of infection.²⁷

Future research has to focus on optimization of the growth factor concentration in PRP, the effects of white blood cells, and the systemic results of PRP treatment.

Conclusion

The PRP local injection is a new, autologous, readily available and well tolerated therapy, with prolonged effect and safe choice of therapy for chronic PF  and is not inferior to steroid injection in a short term up. Steroid therapy effect appears in a short period , but PRP has a prolonged effect. Comparing the long-term efficacy, PRP injection is better than steroid injection in relieving the pain of planar fasciitis and in improvement of the function of the patient’s foot.