The diabetic foot probe-to-bone test is one of the highest-specificity bedside investigations in primary care for diagnosing osteomyelitis in a diabetic foot ulcer — the technique: with a sterile blunt metal probe (or a sterile cotton-tip applicator with the cotton removed, or a sterile dental probe), gently probe the base of the diabetic foot ulcer. If the probe contacts hard, gritty bone, the test is positive. The positive predictive value of probe-to-bone positive is approximately 89% for osteomyelitis in a diabetic foot ulcer — almost all probe-to-bone positive ulcers have osteomyelitis. A negative probe-to-bone test in a non-infected-appearing diabetic foot ulcer has a negative predictive value of approximately 96%, making osteomyelitis unlikely. This test takes 5 seconds in a properly positioned patient and dramatically changes the urgency of management — probe-to-bone positive = same-day hospital referral for MRI foot + IV antibiotics + surgical debridement planning.

Morton's neuroma management in primary care is frequently inadequate because the diagnosis is missed — the neuroma (actually a perineural fibrosis, not a true neuroma) forms in the common digital nerve between the metatarsal heads, most commonly between the 3rd and 4th toes. The presenting symptoms: burning, sharp, or shooting pain in the forefoot radiating into the affected toes (particularly the 3rd and 4th), often described as 'walking on a pebble,' worsened by tight footwear and high heels, relieved by removing shoes and massaging the foot. The key examination finding: Mulder's click sign — with one hand compressing the metatarsal heads laterally (squeezing the forefoot) while the other hand's thumb and index finger palpate the interspace from above and below, a palpable and audible 'click' produced by moving the neuroma suggests the diagnosis. The clinical approach: wide-toe-box footwear + metatarsal pad (raises the metatarsal arch, reducing nerve compression) is first-line. Ultrasound-guided corticosteroid injection into the interspace if conservative measures fail. Surgical excision if two injections ineffective.

The 10g Semmes-Weinstein monofilament test for diabetic foot neuropathy is the most important screening examination for identifying feet at risk of neuropathic ulceration — it should be performed at every annual diabetic foot check and at any consultation where a diabetic patient presents with a foot complaint. The technique: press the monofilament perpendicular to the skin surface with enough force to bend it (the calibrated monofilament applies 10g of force when buckled). Test four sites on each foot: plantar aspect of hallux, plantar first, third, and fifth metatarsal heads. Ask the patient to say 'yes' when they feel it (eyes closed). A patient who cannot feel the monofilament at one or more sites has significant peripheral neuropathy — their foot cannot generate protective pain, meaning they can sustain tissue-damaging pressure without awareness. These patients need: enhanced foot protection education, footwear advice, regular podiatry, and annual diabetic foot reviews upgraded to 3-6 monthly.

The nail avulsion and phenolisation procedure for recurrent ingrown toenail is a primary care procedure that many GPs are trained to perform — it involves: LA ring block of the great toe (2% lidocaine without adrenaline, approximately 3-4 mL injected at base of toe — medial and lateral digital nerves); removal of the affected lateral nail portion (approximately 3-4 mm); application of 88% phenol solution to the exposed nail matrix for 30 seconds (three 30-second applications with dry cotton swabs) to chemically ablate the matrix and prevent regrowth of the lateral nail edge; and neutralisation with surgical spirit. The recurrence rate after phenolisation is approximately 5-15% (compared to 70-80% for nail avulsion alone). Patients must be warned: the toe looks alarming for 2-4 weeks (yellow-green discharge from phenolised tissue is expected); healing takes 4-6 weeks; keep wound dry except for daily salt water soaks; wear open-toed footwear for 4-6 weeks.

The Charcot neuroarthropathy (Charcot foot) is one of the most devastating complications of diabetic peripheral neuropathy and is frequently missed in primary care — the acute Charcot foot presents as a unilateral warm, swollen, erythematous foot in a patient with significant diabetic peripheral neuropathy. The swelling and erythema are so similar to cellulitis, gout, or DVT that the correct diagnosis is often delayed. The key distinguishing feature: the Charcot foot is typically PAINLESS despite dramatic swelling and warmth — because the neuropathy prevents the patient from feeling pain. A diabetic patient with 'cellulitis' of the foot that is not improving with antibiotics, or with a swollen foot that does not hurt, must be referred to the diabetic foot team for MRI (which shows bone marrow oedema and fragmentation, pathognomonic of Charcot). The treatment window is critical: early immobilisation with a total contact cast (TCC) prevents the collapse of the foot architecture; delayed treatment leads to irreversible midfoot or hindfoot collapse (rocker-bottom foot deformity) requiring amputation.

The colchicine dosing in gout has been revised significantly from earlier high-dose protocols — the traditional high-dose regimen (1 mg loading + 0.5 mg every 2 hours until diarrhoea, nausea, or pain relief) is no longer recommended by EULAR or NICE due to the high rates of GI toxicity (diarrhoea occurs in approximately 80% of patients on the old protocol). The current NICE/EULAR-recommended dosing for acute gout is the low-dose regimen: colchicine 500 mcg (0.5 mg) three times daily for 5 days. This achieves the same clinical efficacy as the high-dose regimen (NNT approximately 2 for 50% pain relief at 24 hours) with significantly fewer adverse effects. In patients with eGFR 10-50 mL/min, reduce to 500 mcg BD. In patients with eGFR <10 or on dialysis, avoid colchicine. Drug interaction: clarithromycin and other CYP3A4 inhibitors dramatically increase colchicine plasma levels and can cause life-threatening colchicine toxicity (myopathy, pancytopenia) — halve the colchicine dose or avoid.

The terbinafine 16-week course for toenail onychomycosis requires specific patient counselling about the expected timeline to visible improvement — terbinafine kills the fungus within the first weeks of treatment, but visible nail improvement lags 6-12 months behind the end of treatment because the toenail grows at approximately 1-1.5 mm per month and the new clear nail must physically grow out from the matrix. Patients who stop terbinafine at 3-4 weeks because 'the nail doesn't look any better' are making a common and understandable error. The correct counselling: 'The treatment takes 16 weeks and then the nail may take a further 6-12 months to look completely clear — this is because new healthy nail must grow out slowly from the root. The fact that it doesn't look different after a few weeks is completely normal.' GP review at 4 months: confirm compliance + check LFTs (hepatotoxicity monitoring). Recurrence counselling: approximately 25% recurrence at 5 years — re-treat promptly.

The metatarsal dome pad placement is critically important for its effectiveness — it must be placed PROXIMAL to (just behind) the metatarsal heads, not under them. A correctly positioned metatarsal dome pad lifts the metatarsal shaft (like a keystone under an arch), spreading the transverse metatarsal arch and separating the metatarsal heads, thereby decompressing the interdigital nerves. If placed directly under the metatarsal heads (the intuitive but incorrect position), it increases rather than decreases pressure on the nerve. The correct placement: the posterior edge of the pad should be approximately 1-1.5 cm behind the metatarsal head (the ball of the foot). Many patients and podiatrists use pre-fabricated metatarsal pads without explaining this positioning detail, resulting in ineffective treatment and unnecessary escalation to steroid injection or surgery. GPs advising patients on metatarsal pads should demonstrate placement on an anatomical model or clear diagram.

The annual diabetic foot risk stratification and follow-up frequency is a NICE NG28 and NICE NG19 quality standard — low risk (normal sensation, normal pulses, no deformity, no ulcer history) = annual review by GP or practice nurse; moderate risk (one of: neuropathy, absent pulses, deformity, skin changes) = 3-6 monthly by community podiatry; high risk (two or more risk factors from: neuropathy, absent pulses, deformity, skin changes, previous ulcer, Charcot) = 1-3 monthly by specialist podiatry or diabetic foot team. Identifying the correct risk category and ensuring the appropriate follow-up is arranged is a GP quality standard. A high-risk diabetic foot patient who is only reviewed annually (as if low risk) represents a clinical governance failure. The QOF indicator DM019 requires that all registered diabetes patients have a foot examination with neuropathy assessment and vascular assessment at least annually — GPs should ensure this is recorded in the diabetic annual review template.