Plantar Fasciitis

Plantar fasciitis is the most common cause of heel pain in adults, accounting for approximately 80% of heel pain presentations. Despite the name, it is primarily a degenerative condition (fasciosis or enthesopathy) rather than an inflammatory one — histological studies show collagen degeneration, fibroblast proliferation, and matrix changes without significant inflammatory infiltrate in chronic cases. Understanding this distinction is clinically important as it influences management, particularly the role of corticosteroid injections.

• Incidence: approximately 1 million physician visits annually in the USA; affects approximately 10% of the population at some point; bilateral in approximately 30% of cases
• The plantar fascia originates from the medial calcaneal tuberosity and fans out to insert at the base of the proximal phalanges; it supports the medial longitudinal arch and assists toe-off via the windlass mechanism
• Windlass mechanism: as the toes are dorsiflexed during heel rise, the plantar fascia tightens (windlass effect), raising the arch, locking the midfoot, and transferring load to the forefoot; dysfunction of this mechanism or overloading of the plantar fascia at its calcaneal origin produces the characteristic insertion enthesopathy
• Pathophysiology: repetitive microtrauma at the calcaneal origin → degenerative change (type III collagen, mucoid degeneration, matrix disruption) → periosteal reaction at enthesis → heel spur formation (not the cause of pain — occurs at the flexor digitorum brevis origin, not the plantar fascia origin)
• Risk factors: obesity (BMI >30), prolonged standing, reduced ankle dorsiflexion (tight Achilles/gastrocnemius), pes planus, pes cavus, sudden increase in activity, running on hard surfaces, middle age (40–60 years)

• Classic presentation: sharp, stabbing medial plantar heel pain worst with the first steps in the morning or after prolonged rest ("post-static dyskinesia"); improves after walking a short distance; worsens again with prolonged activity; gradual onset over weeks to months
• Physical examination: maximal tenderness at the medial calcaneal tuberosity (medial process) on direct palpation — the most reliable clinical finding; tenderness along the plantar fascia in approximately 50%; pain reproduced by passive dorsiflexion of the toes (windlass test)
• Windlass test: extend the great toe passively — positive if this reproduces plantar heel pain; reflects tensioning of the plantar fascia
• Ankle dorsiflexion assessment: reduced ankle dorsiflexion is the most consistent biomechanical risk factor; Silverskiöld test differentiates gastrocnemius (corrects with knee flexion) from combined gastrocnemius-soleus tightness; limitation in dorsiflexion predicts poor response to simple stretching and may require targeted intervention
• Diagnosis is primarily clinical — imaging is not required for straightforward cases but should be performed when the diagnosis is uncertain or when conservative management fails

• Baxter nerve (first branch of lateral plantar nerve): commonly overlooked cause of chronic heel pain; the nerve runs between the deep fascia of the abductor hallucis and the medial margin of the quadratus plantae; compressed in patients with plantar fasciitis (both conditions may coexist); suspect in patients with persistent heel pain not responding to plantar fasciitis treatment; EMG/NCS and USS can confirm

• Plain radiographs: heel spur visible in approximately 50% of plantar fasciitis patients — but also present in 15–20% of asymptomatic individuals; heel spur at the calcaneal origin of plantar fascia is NOT a reliable indicator of plantar fasciitis and is not the cause of pain; assess for stress fracture, bone tumour, or calcaneal erosion (inflammatory arthropathy)
• Heel spur: present in ~50% of plantar fasciitis and ~20% of asymptomatic population; NOT diagnostic and NOT the cause of pain; represents reactive periosteal new bone at the enthesis
• MRI: investigation of choice when diagnosis is uncertain; confirms plantar fascia thickening and signal change at the calcaneal enthesis; rules out calcaneal stress fracture, bone marrow lesion, or other soft tissue pathology; plantar fascia thickness >4 mm on MRI suggests fasciitis
• USS: dynamic assessment; plantar fascia thickening at origin (>4 mm); hypoechogenicity indicating degeneration; guides corticosteroid injection placement; cost-effective alternative to MRI for straightforward cases
• Bloods: if bilateral heel pain, check ESR, CRP, HLA-B27, uric acid to screen for inflammatory arthropathy or gout

Approximately 90% of patients with plantar fasciitis improve with non-operative treatment within 12 months. A structured, stepwise approach is recommended.

• First-line: plantar fascia and gastrocnemius stretching exercises (Digiovanni protocol — seated non-weight-bearing plantar fascia stretch first thing in the morning before standing); NSAIDS for pain relief; activity modification; cushioned heel pad or semi-rigid orthotics; weight reduction counselling
• DiGiovanni stretching protocol: patient seated, crosses the affected foot over the contralateral knee; pulls the toes back towards the shin (dorsiflexes the toes), creating tension in the plantar fascia; holds for 10 seconds × 10 repetitions before the first step out of bed; evidence-based and superior to Achilles stretching alone for plantar fasciitis
• Night splints: maintain ankle at 5° dorsiflexion overnight — prevents tightening of plantar fascia and Achilles during sleep; reduces morning pain significantly; compliance is the main limitation (uncomfortable)
• Corticosteroid injection: USS-guided injection at the plantar fascia origin; provides short-term (4–6 weeks) pain relief; risk of plantar fascia rupture (approximately 10%) and fat pad atrophy with repeated injections; limit to 1–2 injections; warn patients about rupture risk and avoid high-demand activities immediately after injection
• Extracorporeal shockwave therapy (ESWT): for chronic plantar fasciitis (>3 months) refractory to first-line treatment; high-energy or low-energy protocols; evidence of moderate benefit; no clear consensus on optimal protocol; no incision, minimal risk
• Platelet-rich plasma (PRP): increasingly used as an alternative to corticosteroid; avoids fat pad atrophy and rupture risk; evidence mixed but growing; may have longer-lasting effect than corticosteroid

• Reserved for patients who fail 6–12 months of structured non-operative treatment (approximately 5–10% of patients)
• Endoscopic plantar fascia release (EPFR): most common surgical procedure; arthroscopic release of the medial one-third to one-half of the plantar fascia at the calcaneal origin; minimally invasive; release no more than 50% of plantar fascia width — excessive release causes lateral column overloading and medial longitudinal arch destabilisation; flatfoot deformity can result from over-release
• Open plantar fascia release: traditional approach; direct visualisation; also allows Baxter nerve decompression if coexisting nerve entrapment; heel spur excision can be performed simultaneously if symptomatic
• Gastrocnemius recession (Strayer procedure): for patients with plantar fasciitis + reduced ankle dorsiflexion; addresses the biomechanical driver; can be combined with plantar fascia release; increasing evidence supports its role as a primary or combined procedure
• Outcomes: approximately 75–85% good or excellent results after surgery; outcomes less predictable than for non-operative treatment; complications include medial plantar nerve injury, scar tenderness, calcaneal stress fracture, and deformity from over-release

• Plantar fascia rupture: can occur spontaneously or after corticosteroid injection; presents with acute heel pain and inability to weight-bear; MRI confirms; most heal conservatively with a walking boot and gradual return to activity; paradoxically, some patients with chronic plantar fasciitis notice pain improvement after rupture — the release of tension in the degenerate fascia provides relief; rarely requires surgical repair
• Bilateral plantar fasciitis: always consider systemic cause — bilateral enthesitis at multiple sites suggests seronegative spondyloarthropathy (ankylosing spondylitis, psoriatic arthritis, reactive arthritis); check HLA-B27, ESR, CRP, uric acid; refer to rheumatology if suspected; management of the underlying inflammatory disease is essential alongside local treatment
• Calcaneal stress fracture mimicking plantar fasciitis: presents identically in early stages; the squeeze test (medial and lateral compression of the calcaneus) is positive in stress fracture but not in plantar fasciitis; MRI is diagnostic; occurs in runners, military recruits, and osteoporotic patients; immobilisation and cessation of impact activity
• Gastrocnemius tightness as primary driver: increasing evidence implicates isolated gastrocnemius tightness (Silverskiöld test positive with knee extended but negative with knee flexed) as a primary biomechanical driver of plantar fasciitis; gastrocnemius recession alone or combined with plantar fascia release in this subgroup produces better outcomes than fascia release alone; routine ankle dorsiflexion assessment is therefore essential in all patients

• Classic presentation: morning heel pain worst with first steps; medial calcaneal tuberosity tenderness; improves after walking; post-static dyskinesia pattern
• Heel spur: present in 50% of plantar fasciitis AND 20% of asymptomatic — NOT diagnostic; NOT the cause of pain
• Windlass mechanism: toe dorsiflexion tightens plantar fascia and raises arch; windlass test reproduces pain = plantar fascia pathology
• DiGiovanni protocol: seated plantar fascia stretch before first step; 10 × 10 seconds every morning; first-line evidence-based treatment
• Corticosteroid injection: short-term benefit (4–6 weeks); risk of plantar fascia rupture (~10%) and fat pad atrophy; limit to 1–2 injections; USS-guided preferred
• Baxter nerve: first branch lateral plantar nerve; entrapped with plantar fasciitis; suspect in resistant cases; coexists in up to 20% of plantar fasciitis
• Endoscopic plantar fascia release: release medial 50% maximum — over-release → lateral column overload → flatfoot
• Bilateral heel pain + back pain + HLA-B27 positive = seronegative spondyloarthropathy; refer rheumatology
• 90% of plantar fasciitis resolves with non-operative management within 12 months; surgery reserved for 5–10% refractory cases
• Gastrocnemius tightness (Silverskiöld positive): consider gastrocnemius recession alone or combined with fascia release; addresses the biomechanical driver