Foot Pain Algorithm · Reasoning GP

Safety

Exclude emergencies & can't-miss diagnoses first

Done

Ask about onset, trauma, systemic features, and vascular/neuropathic risk before any further assessment.

Open fracture / dislocation Visible bone, gross deformity, acute trauma → 999 immediately

Acute limb ischaemia 6 Ps: Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, Perishing cold → 999 vascular emergency

Necrotising fasciitis Rapidly spreading erythema, severe disproportionate pain, sepsis, crepitus → 999 (surgical emergency; NICE NG51)

Septic arthritis Hot swollen joint + fever + raised CRP/WCC → same-day orthopaedics; joint must be aspirated within hours

Diabetic foot emergency Ulceration + infection/ischaemia/Charcot in diabetic patient → same-day diabetic foot team (NICE NG19)

Deep vein thrombosis Unilateral calf swelling, pain, erythema post-immobility/travel → same-day DVTUS / Wells & D-dimer pathway

Stress fracture with high-risk site Anterior tibial cortex, femoral neck, navicular, 5th metatarsal (Jones) in athlete — continued activity risks complete fracture → urgent orthopaedics

Malignancy / Paget's disease Night pain, bony swelling, age >50, no trauma, weight loss → 2WW bone tumour pathway (NICE NG12)

Missed vascular emergencies and necrotising fasciitis carry catastrophic consequences within hours. Acute limb ischaemia requires revascularisation within 6 hours to avoid amputation. Septic arthritis destroys cartilage within 72 hours if untreated. Diabetic foot infections account for over 50% of non-traumatic amputations in the UK (NICE NG19); identifying them early and referring same-day to a multidisciplinary diabetic foot team is a NICE quality standard. Stress fractures at high-risk sites (navicular, Jones) progress to complete fracture with permanent disability if loading continues — early orthopaedic input is mandatory.

Diagnose

Structured history — localise and characterise the pain

Done

Use anatomical location + onset + aggravating factors as your primary diagnostic filter. The foot has 6 key zones — establish which first.

Location

Heel (plantar/posterior), midfoot arch, forefoot/metatarsal heads, toes, diffuse — narrows differential immediately

Onset & duration

Acute (trauma, gout, septic arthritis) vs insidious (>6 weeks → plantar fasciitis, stress fracture, Morton's, inflammatory arthritis)

Character

Sharp stabbing (plantar fasciitis, Morton's neuroma), burning (neuropathy), throbbing (gout, infection), aching (structural/mechanical)

Timing

First-step morning pain → plantar fasciitis; post-activity → stress fracture; night pain → gout, neuropathy, malignancy (alarm)

Aggravating/relieving

Weight-bearing worsens most; rest relief supports mechanical cause; NSAIDs dramatically relieve gout & inflammatory arthritis

Radiation

Into toes → Morton's neuroma (3rd–4th webspace), tarsal tunnel; up leg → referred lumbar, DVT, vascular

Associated features

Swelling, erythema, fever, skin changes, nail dystrophy, numbness/tingling, bilateral symptoms

Systemic review

Diabetes, gout history, psoriasis, IBD, recent sore throat/urethritis (reactive arthritis), RA, SLE, medications (fluoroquinolones → tendinopathy)

Red flag symptoms

Weight loss, night sweats, constant night pain, age >50 with no prior diagnosis → screen for malignancy/Paget's

Activity & footwear

Recent increase in training load (stress fracture), occupation (prolonged standing), footwear type and fit

Location alone narrows the differential to 2–3 diagnoses in most cases. Plantar heel pain in a 40–60 year old with first-step pain is plantar fasciitis until proven otherwise (>80% of plantar heel presentations). Asking about morning stiffness lasting >30 minutes and involvement of other joints differentiates inflammatory arthritis (requiring DMARD therapy) from mechanical causes. The fluoroquinolone/tendinopathy link is a commonly missed iatrogenic cause. Bilateral symptoms should always prompt systemic disease screening.

Diagnose

Classify by anatomical zone & likely diagnosis

Done

Match location to the most likely diagnosis. Most foot pain diagnoses are clinical — classification guides investigation and treatment choice.

🟥 Plantar heel

Plantar fasciitis (most common) — first-step pain, worse AM, tender at medial calcaneal tuberosity. Also: Fat pad atrophy (elderly), Calcaneal stress fracture (squeeze test positive), Tarsal tunnel syndrome (burning, tingling medial ankle)

🟧 Posterior heel

Achilles tendinopathy — mid-portion (2–6 cm above insertion) vs insertional. Also: Retrocalcaneal bursitis, Haglund's deformity (prominent posterosuperior calcaneus)

🟨 Midfoot / arch

Tibialis posterior tendinopathy — medial arch pain, flat foot progression, post-menopausal women. Also: Midfoot OA (dorsal osteophytes), Navicular stress fracture, Lisfranc injury (post-trauma — do not miss)

🟩 Forefoot / MTP joints

Morton's neuroma (3rd–4th webspace burning, Mulder's click). Metatarsal stress fracture (2nd/3rd shaft, focal tenderness). Freiberg's disease (2nd MTP, adolescents). Sesamoiditis (under 1st MTP)

🟦 Toes

Hallux valgus (1st MTP deviation + bunion). Hallux rigidus (1st MTP stiffness/OA). Hammer/claw toes (deformity + dorsal corn). Ingrown toenail (lateral nail fold infection)

🟪 Diffuse / systemic

Gout (acute 1st MTP, red, swollen — podagra in 50%). Psoriatic arthritis (dactylitis, nail changes). Reactive arthritis (asymmetric, post-infection). RA (symmetric MTP synovitis). Peripheral neuropathy (burning bilateral, distal, diabetes/alcohol)

Correct anatomical classification prevents treatment mismatches. Plantar fasciitis and calcaneal stress fracture both present with heel pain but require opposite initial management (exercise vs offloading/imaging). Missing a Lisfranc injury (ligamentous injury between 1st–2nd metatarsals and cuneiforms) leads to chronic midfoot instability and early arthritis — weight-bearing X-rays are essential if suspected after trauma. Inflammatory arthritides (RA, psoriatic, reactive) need early DMARD therapy; delayed diagnosis accelerates joint destruction.

Diagnose

Targeted foot examination — look, feel, move, special tests

Done

Examine weight-bearing and non-weight-bearing. Always check both feet. Examine footwear wear patterns — they reveal gait and loading abnormalities.

Inspection (standing)

Arch height (pes planus / cavus), alignment, swelling, erythema, skin, nails, callus pattern, toe deformities. Observe gait from behind and front

Calcaneal squeeze test

Mediolateral compression of calcaneus — positive (pain) → calcaneal stress fracture; highly sensitive in runners

Plantar fascia palpation

Direct palpation medial calcaneal tuberosity — sharp localised pain = plantar fasciitis. Windlass test: passive great toe dorsiflexion recreates pain

Achilles tendon

Palpate mid-portion and insertion; assess Thompson's test (calf squeeze — no plantarflexion = complete rupture → 999); crepitus suggests tendinopathy

MTP joint assessment

Squeeze across metatarsal heads (metatarsalgia, RA synovitis). Mulder's click test for Morton's neuroma (compression + dorsoplantar squeeze — audible click + pain). Assess 1st MTP range for hallux rigidus

Tarsal tunnel

Tinel's sign: percuss posterior to medial malleolus — tingling in plantar foot distribution = tarsal tunnel syndrome

Neurovascular

Dorsalis pedis + posterior tibial pulses; capillary refill <2 sec; light touch/monofilament sensation (10g Semmes-Weinstein); vibration (128Hz tuning fork)

Ankle / subtalar

Assess dorsiflexion (normal ≥10° weight-bearing); subtalar inversion/eversion; pain on resisted tibialis posterior (tendinopathy vs tear)

Targeted examination discriminates between diagnoses that history alone cannot. Thompson's test must be performed whenever Achilles rupture is possible — a palpable gap alone has poor sensitivity. Monofilament testing (10g Semmes-Weinstein) is the NICE-recommended standard for peripheral neuropathy screening in diabetes (NG19); missing neuropathy means missing the patient's ulcer risk. Mulder's click has ~90% sensitivity for Morton's neuroma when combined with compression, avoiding unnecessary MRI in many cases. Always assess the entire kinetic chain — limited ankle dorsiflexion (e.g., tight gastrocnemius) is a primary driver of plantar fasciitis and needs addressing in treatment.

Diagnose

Targeted investigations — investigate selectively, not reflexively

Done

Most mechanical foot pain diagnoses are clinical. Request investigations only when they will change management or rule out serious pathology.

X-ray foot/ankle 1st line

Weight-bearing views (AP + lateral) for: suspected fracture, Lisfranc injury, OA, hallux valgus, Charcot. Not routine for plantar fasciitis — heel spurs correlate poorly with symptoms (present in 50% asymptomatic adults)

Bloods — gout screen

Serum urate (note: may be normal during acute attack); urea & creatinine; eGFR baseline before urate-lowering therapy. Urate >360 μmol/L confirms hyperuricaemia

Bloods — inflammatory

CRP, ESR, FBC if: suspected septic arthritis, inflammatory arthritis, or systemic disease. Anti-CCP + RF if RA suspected. HLA-B27 if reactive/psoriatic arthritis

Bloods — metabolic

HbA1c + fasting glucose if neuropathy or diabetic foot; calcium, ALP if Paget's suspected (markedly raised ALP); vitamin D if diffuse pain

MRI 2nd line

Suspected: navicular/Jones stress fracture (plain X-ray initially normal), Morton's neuroma if uncertain, tarsal tunnel, osteonecrosis, soft tissue tumour. Refer for MRI via radiology — do not arrange CT for bony stress injury (MRI superior)

Ultrasound

Plantar fascia thickness >4 mm supports fasciitis; Achilles tendinopathy assessment; Morton's neuroma if clinical diagnosis uncertain; guided injection planning

Joint aspiration

If septic arthritis or gout is suspected — same-day orthopaedics/rheumatology for aspiration. Polarised light microscopy: negatively birefringent urate crystals = gout; positively birefringent = pseudogout

Do NOT routinely order

MRI for uncomplicated plantar fasciitis; bone scan (largely superseded by MRI); nerve conduction studies in primary care (refer if tarsal tunnel confirmed clinically)

Over-investigation of plantar heel pain is common and delays treatment. Up to 60% of asymptomatic adults have heel spurs on X-ray; requesting routine X-ray creates false causality and unnecessary patient concern. However, plain X-ray weight-bearing views are critical for Lisfranc injury — non-weight-bearing views miss up to 25% of injuries. MRI is the gold standard for navicular and Jones stress fractures as plain X-rays are normal in up to 30–40% of cases in the first 2 weeks. Joint aspiration in suspected septic arthritis is both diagnostic and therapeutic — do not delay for imaging.

Refer

Referral criteria — know when to escalate and to whom

Done

Most foot pain is managed in primary care. Refer early for high-risk diagnoses, failed conservative management, or when specialist intervention is required.

999 Emergency

999 Acute limb ischaemia, open fracture/dislocation, necrotising fasciitis, complete Achilles rupture with neurovascular compromise, sepsis from foot source

Same-day urgent

Same-day Suspected septic arthritis (hot swollen joint + fever) → orthopaedics/rheumatology for aspiration. Diabetic foot with ulcer + infection/ischaemia → diabetic foot MDT (NICE NG19 standard). Suspected DVT → DVTUS via local pathway

2-Week Wait

2WW Persistent bony swelling, night pain, unexplained lytic/sclerotic lesion on X-ray, age >50 with no trauma → sarcoma/bone tumour 2WW (NICE NG12). New painless nodule in soft tissue >5 cm → soft tissue sarcoma 2WW

Urgent routine (2–4 wks)

High-risk stress fractures (navicular, Jones, 5th metatarsal) → orthopaedics for non-weight-bearing/surgical decision. Suspected Lisfranc injury → orthopaedics. Suspected Charcot foot → diabetic foot team. Acute gout not responding to first-line therapy → rheumatology

Routine orthopaedics / MSK

Hallux valgus/rigidus affecting quality of life and failed conservative management (6 months). Plantar fasciitis failed 6-month conservative treatment. Morton's neuroma failing conservative measures. Hammer/claw toes with pain/ulceration. Tarsal tunnel syndrome confirmed clinically

Podiatry Primary Care

Diabetic foot annual review + any foot concern in diabetics. Nail pathology (ingrown nails, onychomycosis resistant to treatment). Orthotics assessment for plantar fasciitis, tibialis posterior dysfunction, metatarsalgia. Callus/corn management. Verruca pedis not resolving

Physiotherapy

Plantar fasciitis, Achilles tendinopathy (eccentric loading programme), tibialis posterior tendinopathy, post-fracture rehabilitation. Self-refer where available or GP refer

Rheumatology

New inflammatory arthritis (RA, psoriatic, reactive), recurrent gout with renal impairment, suspected crystal arthropathy needing DMARD decision, seronegative arthropathy

Vascular surgery

ABPI <0.8 (peripheral arterial disease), non-healing ulcer, rest pain, critical ischaemia (ABPI <0.5)

The diabetic foot pathway is a NICE quality standard — same-day referral to the MDT diabetic foot team for any infected or ischaemic diabetic foot ulcer is mandatory (NICE QS119). Delayed referral is the most common preventable cause of lower limb amputation. Jones fractures (5th metatarsal base, zone 2) have a high non-union rate with conservative management — early orthopaedic input determines whether surgical fixation is needed, particularly in athletes. Early podiatry referral for diabetic patients without current ulcers reduces amputation risk by 50% (NICE NG19 evidence review).

Treat

Condition-specific treatment — structured by diagnosis

Done

Treatment is diagnosis-specific. Address the four most common diagnoses in primary care below. Always start with conservative measures before escalation.

① Plantar Fasciitis (most common)

Step 1Load management + analgesia: Reduce high-impact activity (not rest). Paracetamol 1g QDS and/or Ibuprofen 400 mg TDS with food (if no CI). Silicone heel cup / cushioned footwear immediately

Step 2Physiotherapy — stretching programme: Plantar fascia stretch (towel toe-curls) and calf stretches (Achilles/gastrocnemius) 3× daily. Night splint if early morning pain prominent. 70–80% resolve by 12 weeks

Step 3Orthotics & podiatry: Custom semi-rigid orthotics for pronation/pes planus. Podiatry referral for taping, assessment. Consider if failed step 2 at 6 weeks

Step 4Corticosteroid injection (if failed 3 months conservative): Methylprednisolone 40 mg + 1% lidocaine into plantar fascia insertion (ultrasound-guided preferred). Short-term benefit; warn: fat pad atrophy risk with repeated injections; do not give more than 2–3 lifetime injections

Step 5Specialist referral at 6 months if failed all above: Extracorporeal shockwave therapy (ESWT — NICE IPG311 supports use), platelet-rich plasma, or surgical plantar fasciotomy (last resort)

② Acute Gout

First-line (no CI)

Naproxen NSAID

500 mg BD with food for 5–7 days. Add PPI (omeprazole 20 mg OD) if >65 yrs or GI risk. Avoid aspirin (raises urate)

CKD / NSAID intolerant

Colchicine 1st line alt.

500 mcg BD–TDS. Continue until attack resolves (usually 7–10 days). Reduce dose in eGFR <30. Watch for diarrhoea/GI upset

Both contraindicated / severe

Prednisolone Oral steroid

25–35 mg OD for 5 days, then stop (no taper needed for short course). Check HbA1c / blood glucose if diabetic

Urate-lowering therapy

Start allopurinol 100 mg OD (NOT during acute attack — wait 4 weeks after resolution). Increase by 100 mg monthly to target serum urate <300 μmol/L (CKS recommendation). Titrate to max 900 mg OD. Start prophylactic colchicine 500 mcg OD for 6 months when initiating allopurinol (prevents flares)

Monitoring on allopurinol

FBC, U&E, LFT at baseline; repeat at 3 months; check serum urate annually once at target. Warn: allopurinol hypersensitivity syndrome (rare but severe — stop if rash, fever, lymphadenopathy)

③ Achilles Tendinopathy

Step 1Load modification: Reduce training load by 50%; avoid hills/barefoot. Heel raise (1–2 cm) immediately — offloads Achilles. Naproxen 500 mg BD short course for acute pain if no CI

Step 2Eccentric loading programme (Alfredson protocol): Heel drops off step — eccentric phase only, 3 sets × 15 reps twice daily, 12 weeks. Physiotherapy referral for supervised programme. Evidence: 60–80% success rate at 12 weeks (Alfredson 1998, BJSM)

Step 3Failed at 3 months: Ultrasound-guided GTN patch (glyceryl trinitrate 1.25 mg/24h patch cut to ¼) applied over tendon — limited evidence; ESWT or PRP injection via sports/orthopaedic referral

⚠ Do NOT inject corticosteroid into or around the Achilles tendon — risk of tendon rupture. Peritendinous steroid injection is contraindicated in Achilles tendinopathy.

④ Inflammatory Arthritis (new presentation)

Acute analgesia

Naproxen 500 mg BD with PPI while awaiting rheumatology. Do not start DMARD without specialist input

RA suspected

Anti-CCP + RF; refer urgently to rheumatology — NICE NG100 recommends referral within 3 weeks of symptom onset. Early DMARD (methotrexate ± hydroxychloroquine) started by specialist

Psoriatic arthritis

Refer rheumatology ± dermatology. NSAIDs first-line symptom control. DMARDs (methotrexate) needed if persistent — specialist decision

Reactive arthritis

Treat underlying infection if active (STI screen, urine culture). NSAIDs. Self-limiting in 3–6 months majority; 25% become chronic — rheumatology if persistent >3 months

Eccentric loading is the gold-standard treatment for Achilles tendinopathy (NNT ≈ 3 for significant improvement at 12 weeks — Alfredson et al, BJSM). The Achilles tendon has poor vascularity; corticosteroid injection causes collagen necrosis and dramatically increases rupture risk — this is a firm contraindication. For gout, starting allopurinol during an acute attack precipitates a further attack by mobilising urate deposits; the 4-week wait is essential. The 6-month colchicine prophylaxis when starting urate-lowering therapy reduces flare risk by 85%. For RA, every week of delay to DMARD therapy correlates with measurable joint erosion progression — urgent rheumatology referral is not optional.

Lifestyle

Non-pharmacological interventions — lifestyle IS treatment

Done

Lifestyle modifications are primary treatment for most foot pain conditions, not adjuncts. Quantify the impact and give specific measurable targets.

Weight management BMI reduction reduces plantar fascia load proportionally. Losing 10 kg reduces plantar fascia tension by ~70 kg per step (approximately 7× body weight force during walking). Target BMI <25; refer to weight management services / NHS Diabetes Prevention Programme if appropriate

Appropriate footwear Supportive shoes with cushioned heel, wide toe box, and rigid midfoot. Avoid flat flip-flops, high heels, and worn-out trainers. Replace running shoes every 500–800 km (every 6–12 months for regular runners). Prescription: "Supportive trainers with heel drop 8–12 mm" for plantar fasciitis

Stretching programme — calf & plantar fascia Towel curls, standing calf stretch (gastrocnemius and soleus — separate stretches), stair stretches. 3 × 30 seconds, 3 times daily, before first steps in the morning. Reduces plantar fasciitis pain by 52% at 8 weeks (Digiovanni 2003, JBJS)

Activity modification — not rest Complete rest is harmful for tendinopathies and plantar fasciitis. Replace high-impact (running, jumping) with low-impact (swimming, cycling) during recovery. Return to running programme: 10% weekly increase in mileage (Couch to 5K structure for beginners)

Dietary modification — gout Reduce: red meat, offal, shellfish, beer, spirits, fructose-sweetened drinks. Increase: low-fat dairy (uricosuric), cherries (reduces flare frequency by 35%), water ≥2L/day. Achieve healthy weight. Avoid crash dieting (increases urate). Alcohol in gout: ≤14 units/week, avoid beer specifically (high purine)

Footwear orthotics & self-management Off-the-shelf silicone heel cups (plantar fasciitis) £5–15 — recommend purchasing immediately. Metatarsal domes for metatarsalgia — position just proximal to MTP heads. Toe spacers for hallux valgus prevention. Custom orthotics via podiatry if significant biomechanical deformity

Smoking cessation Smoking reduces peripheral perfusion and impairs tendon healing. Relevant for all tendinopathies and critical for diabetic foot disease (smoking doubles amputation risk in diabetics). Refer to NHS Stop Smoking services; offer NRT/varenicline (NICE PH10)

Diabetic foot self-care Daily foot inspection (mirror if needed). Moisturise (avoid between toes). Never walk barefoot. Wear properly fitting shoes and specialist diabetic socks. Attend annual podiatry review (NICE NG28). Report any new blister, crack, discolouration, or break in skin within 24 hours

Footwear change is the single most impactful immediate intervention for most mechanical foot pain. Studies show that 78% of plantar fasciitis patients have inappropriate footwear at presentation. Cherry consumption reduces acute gout flare frequency by 35% (Zhang 2012, Arthritis & Rheumatism); combined with reduced alcohol and purine load, dietary change reduces serum urate by 60–90 μmol/L — comparable to low-dose allopurinol in mild cases. Self-care education in diabetic foot disease reduces amputation rates by 50% — it is a NICE quality indicator and CCG performance metric (QS119). Embed these as active prescriptions, not general advice.

Safety

Follow-up, monitoring & safety-netting

Done

Always close the consultation with explicit safety-netting. Tell the patient exactly what symptoms should prompt them to return and when to call 999.

1–2 weeks

Acute gout: confirm resolution, check renal function if NSAID/colchicine used, plan urate-lowering therapy. Suspected stress fracture: X-ray result review + orthopaedic referral outcome. New diagnosis: confirm patient understands self-management plan

4–6 weeks

Plantar fasciitis / tendinopathy: assess adherence to stretching programme; if no improvement, progress to step 3 (orthotics, physiotherapy). Inflammatory arthritis: confirm rheumatology referral accepted and appointment booked

3 months

Plantar fasciitis: reassess — 80% should show improvement. If not, consider corticosteroid injection or podiatry referral. Gout on allopurinol: recheck serum urate, renal function, LFT; increase allopurinol dose if urate >300 μmol/L

6 months

Failed conservative foot pain: refer orthopaedics/podiatry if not already done. Gout: review serum urate target achieved (<300 μmol/L); consider stopping prophylactic colchicine if >6 months flare-free on allopurinol

Annual

Diabetic foot: mandatory annual podiatry/GP review with monofilament testing, ABPI, pulse check, visual skin/nail inspection — NICE NG28 requirement. Gout: serum urate, eGFR, BP annually on allopurinol

Safety-net → 999

999 Sudden severe pain + pale/cold foot + absent pulse (acute ischaemia). Rapidly spreading redness + severe pain + feeling very unwell/fever (necrotising fasciitis). Foot crushing injury / open fracture

Safety-net → same-day GP

Same-day Diabetic patient: any new break in skin, ulcer, blister, or change in foot colour within 24 hours. Non-diabetic: sudden worsening swelling + fever + cannot weight-bear (septic arthritis). Any foot symptom in patient with peripheral vascular disease (ABPI <0.8)

Safety-net → routine

Pain not improving after 4–6 weeks of first-line treatment. New swelling / bony deformity not yet imaged. Spreading rash or nail changes alongside joint pain (psoriatic arthritis). New numbness or tingling in feet

Patient information

Provide written information: NHS Choices foot pain page; Versus Arthritis gout leaflet; Diabetes UK foot care guide. Self-refer to physiotherapy via NHS self-referral where available locally

Explicit safety-netting is an RCGP SCA marking criterion and a patient safety standard. Diabetic foot safety-netting must be specific: "If you develop any new break in the skin, report it within 24 hours" — vague advice leads to delayed presentations and amputation. The 80% resolution rate of plantar fasciitis at 12 months means most patients do not need escalation, but 6-month failure should trigger reassessment rather than continued passive management. Serum urate monitoring on allopurinol is frequently omitted in practice — fewer than 30% of patients on allopurinol are at target (urate <360 μmol/L), driving ongoing crystal deposition and silent joint damage. Follow-up is treatment.