Foot Pain

Introduction

Nearly one quarter of the population is affected by foot or ankle pain at any given time. Foot pain is complex; it presents to primary and secondary care where accurate diagnosis of the pain source and tissue damage can be difficult. This may be due to various pathologies that can give rise to foot pain and the complexity of the biomechanics of the foot and the ankle.

This section is primarily to give an overview of non-traumatic foot pain, its common causes and various management options. Further detailed discussion of the conditions occurs elsewhere in the Hyperbook.

 

Clinical Evaluation

Clinical assessment of the patient includes a detailed history and a thorough - but focused - clinical examination.

 

History

It is important to take a detailed history of the pain and associated features.  It is useful to use the acronym SOCRATES to cover all the history essentials.

Site, Onset, Character, Radiation, Associated factors, Timing, Exacerbating/relieving factors, Severity

Ask about pain at rest and with activity and the effect the pain has on the activities of daily living, sport/leisure, work, physical and mental health, and any other functional limitations.

Complete the history by asking about other relevant medical history, medications and allergies, social history, smoking status and occupation.

 

Clinical Examination

• Assessment of gait, footwear, insoles and orthotics
• Examination of the patient whilst standing: note the alignment of legs, spine, muscle wastage, and asymmetry; note the medial longitudinal arch and hindfoot alignment along with the overall foot shape
• Detailed examination with patient sitting down
  • Look: skin colour, skin changes, nail changes, callus, swelling and deformity; remember to look under the foot for callosities
  • Feel: temperature, cap refill, sensation, pulses, palpation; systematic, relevant approach
  • Move: passive and active; assessment of relevant joint movements; test muscle-tendon unit power: TA, tibialis anterior/posterior, peroneus longus/brevis, EHL, FDL, FHL as appropriate
  • Special tests: ski stance, anterior drawer, inversion stress, external rotation stress, calf squeeze, Coleman block, Semmes-Weinstein monofilament, tarsal tunnel, Mulder’s click, Silfverskiöld etc.

 

Differential Diagnosis

The causes can be categorised either according to the region of the foot (e.g. fore / mid / hind foot) or listed according to the affected tissues.

Common differential diagnoses are listed in the table below:

Skeletal	OA, inflammatory arthropathy, hallux rigidus, stress fracture, osteomyelitis, OCD, AVN, tumour (primary / metastatic), Paget's
Soft tissue	Cellulitis, foreign body, ganglions, ulcers
Tendon / fascia	Tendinitis, tendinopathy, tendon rupture, plantar fasciitis
Neurological	Morton’s neuroma, compressive neuropathy, peripheral neuropathy, CRPS
Nail	Ingrowing toe nails, subungal exostosis
Vascular	Ischaemia, venous changes, compartment syndrome
Biomechanical	Hallux valgus/rigidus, pes planus, pes cavus

 

Investigations

These are to help confirm the diagnosis made from the history and examination. Start simply then more focused:

• Radiographs: weight-bearing AP, oblique, lateral
• Ultrasound: Morton’s neuroma, bursitis, tendinopathies, lumps and bumps, foreign body, targeted injections
• CT scan: coalitions, degenerative changes, 3D orientation
• MRI: tendinopathy, ligament pathologies, degenerative changes, osteochondral defects, stress fractures, bone bruising, Charcot, infection
• SPECT: identify pain generators in multiple pain trigger points
• Blood tests: inflammatory arthropathy, infection, endocrine, diabetes, Vitamin D

 

Types of Pain

Skeletal & Mechanical

• Pain such as tendonitis, stress fracture, corns and callus are routinely attributed - in part or full - to mechanical stress
• Damage occurs when the maximum stress threshold of the tissue or bone is exceeded:
  • Short duration, high magnitude stress
  • Long duration, low magnitude stress
  • Repetitive, moderate magnitude stress

Inflammatory Foot Pain

This can present with a hot, painful, swollen, erythematous foot with reduced function. The management of these patients is via a multidisciplinary approach and to optimise medical management prior to any surgical interventions.

Neuropathic Foot Pain

This can incorporate a variety of symptoms that share similar clinical characteristics, including spontaneous stimulus-dependent and stimulus-independent pain. Pain can be regional and abnormal (e.g. allodynia, dysaesthesia, paraesthesia, hyperaesthesia, hyperalgesia) classically described as “burning”. Features include regional pain, abnormalities of skin temperature and colour, sensory changes, abnormal sweating and oedema.

The pain is typically out of proportion to the initial cause and affected anatomical site. It often has unpredictable treatment responses and may benefit from referral to a pain specialist.