Tendinopathy in Podiatry

What Is Tendinopathy?

Most Common Tendinopathies of the Foot & Ankle

1. Achilles Tendinopathy (most common in podiatry)

• Non-insertional (mid-portion): occurs 2–6 cm proximal to the calcaneal insertion; accounts for ~75% of cases
• Insertional: degenerative process at the calcaneal attachment; accounts for ~25% of cases

• Repetitive eccentric loading (running, jumping)
• Systemic disease (diabetes mellitus, renal disease, ankylosing spondylitis)
• Fluoroquinolone antibiotic use
• Haglund deformity (bony prominence on the posterior calcaneus)

• Pain, swelling, burning, and stiffness in the posterior heel or distal lower leg
• Worsened with push-off activities: walking uphill/stairs, running, jumping
• Palpable swelling and "wet crepitus" from fluid in the peritenon
• Thompson test to assess tendon integrity (squeeze midgastrocnemius — if ankle fails to plantarflex, rupture is suspected)

• X-ray: usually not needed initially; can reveal calcific tendinopathy, Haglund deformity, insertional enthesophyte, or bone spur
• Ultrasound / MRI: for assessing partial tears and extent of degeneration (changes can persist even after functional recovery)

2. Retrocalcaneal Bursitis / Haglund Deformity (associated with insertional tendinopathy)

• Presents with deep posterior heel pain, fullness, and tenderness medial and lateral to the tendon
• Increased pain with dorsiflexion
• Lateral foot X-ray shows the Haglund deformity
• Management: NSAIDs, padding, ice, heel-lift orthotics, shoe modification; steroid injection avoided due to rupture risk
• Surgery: débridement of bursa + excision of Haglund deformity when indicated

Pathophysiology

• Disorganized collagen architecture
• Mucoid degeneration
• Neovascularization (visible on Doppler ultrasound)
• Nociceptor sensitization (explains chronic pain)

Treatment Principles (General)

1. Address inflammation (early): NSAIDs, ice — limited role in chronic disease
2. Stimulate collagen remodeling: eccentric exercise, deep friction massage, needling (percutaneous tenotomy)
3. Autologous growth factor therapy: Platelet-rich plasma (PRP) initiates stalled healing by delivering growth factors to degenerative tissue
4. Surgical fallback: for those who fail 6+ months of conservative care

Tendinopathy — Full Clinical Overview

1. What Contributes to Tendinopathy?

Intrinsic (patient-related)

Extrinsic (environment/activity-related)

2. Pathophysiology of Tendinopathy

Normal Tendon Healing Stages (after acute injury)

1. Hemorrhagic phase — blood accumulates and clots at injury site
2. Inflammatory phase — neutrophils and macrophages initiate phagocytosis, clearing necrotic material
3. Proliferative phase — extrinsic and intrinsic cells migrate and proliferate; type III collagen synthesised (thinner, less tensile strength than native type I)
4. Formative phase (up to 2 months) — collagen fibers mature and orient along tension lines
5. Remodelling phase — ratio of type I:III collagen normalises; physiologic load reintroduced; full tendon strength may take up to 12 weeks to recover

What Goes Wrong in Tendinopathy

• Mechanical overload overwhelms the tendon's ability to repair → failed healing response
• Histopathology shows disorganized collagen architecture, mucoid degeneration, and minimal inflammatory cells — which is why the term tendinosis (not tendinitis) is more accurate for chronic cases
• Neovascularization develops (visible on Doppler ultrasound) — associated with pain via accompanying nerve ingrowth
• Under-recovery between loads prevents the adaptive remodelling that would otherwise strengthen the tendon (increased collagen content, cross-linking, and mucopolysaccharide content require adequate time)
• The condition becomes self-perpetuating: pain → rest → deconditioning → re-loading → pain

Key Concept: The Continuum Model

Reactive tendinopathy → Tendon disrepair → Degenerative tendinopathy

3. Loading — How to Make a Tendon Stronger

The 4-Stage Loading Continuum

Stage 1 — Isometric Exercise

• Purpose: pain relief, maintain muscle activation without tendon movement
• How: sustained muscle contraction against a fixed resistance (no joint movement)
• Example (Achilles): wall sit with single-leg calf hold; seated calf press on leg press machine (45° knee flexion) — hold 45 seconds × 5 reps, 4×/day
• When to use: acute/reactive phase, high pain, in-season athletes who need to continue training
• Key: isometric loading has a neurological analgesic effect on tendon pain — can reduce pain for 45+ minutes post-exercise

Stage 2 — Isotonic (Heavy Slow Resistance)

• Purpose: stimulate collagen synthesis and remodelling
• How: slow concentric + slow eccentric movement under load (3 seconds up / 3 seconds down)
• Example (Achilles): heavy calf raises (bilateral progressing to unilateral), 3–4 × 8–15 reps
• Load: heavy enough to feel difficult by the last 2–3 reps; pain during exercise ≤ 4/10 on NRS, settles within 24 hours
• When to use: pain is manageable; can tolerate load through range

Stage 3 — Eccentric Training

• Purpose: historically the most evidence-based approach, particularly for mid-portion Achilles; loads the tendon during lengthening phase
• Classic Alfredson Protocol (Achilles):
  • Straight-leg calf drop over a step: 3 × 15 reps
  • Bent-knee calf drop (isolates soleus): 3 × 15 reps
  • 2×/day, 7 days/week, for 12 weeks
  • Performed through pain — this is what distinguishes eccentric protocols; pain should not worsen
• Insertional Achilles: standard eccentric drops off a step are contraindicated (compression at insertion worsens it); use floor-level heel drops only

Stage 4 — Energy Storage / Sports-Specific Loading

• Purpose: prepare tendon for high-load, explosive activities (running, jumping)
• How: plyometrics, hopping, bounding, sport-specific drills
• Example: double-leg jumps → single-leg hops → sprint/jump drills
• When to use: only after Stage 2–3 is well tolerated; pain settled

General Loading Rules

• Keep pain during exercise ≤ 4/10 (NRS)
• Pain should return to baseline within 24 hours — if not, reduce load
• Never progress loading if baseline pain is rising
• Tendons take 6–12 weeks minimum for meaningful structural change — set expectations accordingly
• Patients who recur after returning to sport often fail because they skip Stage 3–4

4. Achilles Tendinopathy

• Mid-portion (~75%): 2–6 cm above insertion
• Insertional (~25%): at the calcaneal attachment; associated with Haglund deformity and retrocalcaneal bursitis

• Pain and stiffness in the posterior heel/lower leg
• Worse in the morning, with activity (early stage: after activity; late stage: during and at rest)
• "Arc sign": the area of tendon thickening moves with ankle dorsiflexion (distinguishes from paratendinitis where a fixed area is tender)
• Royal London Hospital test: tenderness reduced with passive dorsiflexion = positive (indicates mid-portion pathology)

• Clinical diagnosis
• Ultrasound: focal thickening, loss of fibrillar echotexture, hypoechoic foci, peritendinous fluid, neovascularization on Doppler
• X-ray: Haglund deformity, insertional enthesophyte/calcification
• MRI: extent of degeneration, partial tears

5. Patellar Tendinopathy ("Jumper's Knee")

• Gradual onset anterior knee pain localised to the patellar tendon
• Tenderness on palpation at the inferior pole of patella
• Pain with loading: squatting, stairs, jumping, prolonged sitting
• A traumatic mechanism, palpable defect, or inability to straight-leg raise → suspect rupture, not tendinopathy

• X-ray: rule out avulsion fracture, assess for patella alta
• Ultrasound: hypoechoic lesion at inferior pole, neovascularization
• MRI: if diagnosis uncertain or surgical planning required

• Eccentric exercise (decline squat protocol): most evidence-based approach
  • Decline board squat at 25°: allows isolated patellar tendon loading
  • Bilateral → unilateral as tolerated; 3 × 15 reps twice daily
• Heavy slow resistance: leg press, leg extension (pain-guided)
• Load management: avoid provocative activities acutely; graduated return
• No role for corticosteroid injection
• Recurrence affects 49% of athletes — long-term load management is critical
• Surgery (debridement): for truly refractory cases only

6. Tibialis Posterior Tendinopathy (PTTD — Posterior Tibial Tendon Dysfunction)

• PTT fails to invert the hindfoot → transverse tarsal joints remain unlocked → medial arch collapses
• Leads to adult-acquired flatfoot deformity (AAFD) — the most common cause
• Multifactorial: hypovascularity, arch overload, activity, obesity, inflammatory arthritis (RA), and spring ligament insufficiency

• Medial ankle/foot pain (early) → lateral ankle pain from subfibular impingement (late)
• Too-many-toes sign: viewing foot from behind, more than 5 toes visible on lateral side
• Failed single-limb heel rise: patient cannot rise onto toes on the affected side — key clinical test of PTT insufficiency
• Standing: asymmetric hindfoot valgus, depressed arch, abducted forefoot

• Isometric tibialis posterior exercise: foot inversion against resistance (theraband) in a pain-free range
• Eccentric tibialis posterior loading: standing on a decline board, controlled eccentric tibial rotation (hindfoot inversion exercises)
• Progress to: single-leg heel rise training (if tolerated), balance/proprioception, resisted inversion in functional positions
• Orthotic support is essential alongside loading exercises — reduces tendon strain during rehabilitation
• AFO for Stage II gives the highest reported success rate alongside physio

• X-ray: Meary's angle (lateral talar–first metatarsal angle) — negative in pes planus; talonavicular uncovering
• Ultrasound: fluid in tendon sheath (tenosynovitis), tendon thickening, neovascularization
• MRI: extent of tendon degeneration, spring ligament status

Summary Comparison Table