Key Facts

Soft tissue injuries are extremely common in emergency medicine, accounting for a large proportion of musculoskeletal ED attendances. Most are managed conservatively, but it is essential to identify injuries requiring surgical intervention or specialist referral.

Epidemiology

Musculoskeletal soft tissue injuries account for approximately 25-30% of all ED attendances. Ankle sprains alone account for approximately 1-2 million UK ED visits per year. Sports injuries are the most common cause in young adults; falls in the elderly.

Aetiology

• Sprains: Excessive force across a joint exceeding ligament tolerance (e.g., inversion ankle injury)
• Strains: Eccentric muscle loading, sudden acceleration/deceleration
• Contusions: Direct blow causing soft tissue damage
• Tendon injuries: Acute rupture (Achilles, patellar, biceps) or chronic tendinopathy

Pathophysiology

Soft tissue injury triggers an inflammatory cascade: haematoma formation, inflammatory cell infiltration (neutrophils, macrophages), followed by proliferative phase (fibroblast collagen synthesis) and remodelling (6 weeks to 12 months). Optimal loading during rehabilitation stimulates collagen alignment and tensile strength. Prolonged immobilisation causes atrophy, stiffness, and delayed recovery.

Ligament Sprain Grading

• Grade I: Stretch without macroscopic tear; mild swelling, no instability, full weight-bearing
• Grade II: Partial tear; moderate swelling, some instability, pain on weight-bearing
• Grade III: Complete rupture; significant swelling, frank instability, unable to weight-bear

Common Injuries

• Lateral ankle sprain: ATFL most commonly injured; inversion mechanism
• Medial collateral ligament (MCL) knee: Valgus force
• ACL rupture: Pivot/deceleration injury; haemarthrosis, positive Lachman's test
• Achilles tendon rupture: Sudden calf pain ('kicked from behind'), palpable gap, positive Simmonds' test
• Rotator cuff tear: Shoulder weakness, pain with overhead activities

Red Flags

• Inability to weight-bear — consider fracture (Ottawa Rules)
• Gross joint instability — complete ligament rupture needing specialist input
• Rapidly increasing swelling with tenseness — compartment syndrome or vascular injury
• Neurovascular deficit distal to injury — urgent assessment
• Knee locked in flexion — meniscal tear with mechanical block

Bedside

• Ottawa Ankle/Knee Rules: Determine need for X-ray
• Neurovascular assessment: Pulses, sensation, motor function
• Specific clinical tests: Simmonds' (Achilles), Lachman's (ACL), valgus/varus stress (collaterals), anterior drawer (ankle ATFL)

Bloods

• Not routinely required for isolated soft tissue injuries

Imaging

• X-ray: Per Ottawa Rules; to exclude fracture
• USS: Tendon injuries (Achilles, rotator cuff), muscle tears, haematomas
• MRI: Gold standard for ligament, meniscal, and complex soft tissue injury assessment

Special Tests

• Compartment pressure monitoring: If compartment syndrome suspected

Non-pharmacological

• POLICE: Protection (brace/splint), Optimal Loading (early controlled movement), Ice (20 min every 2-4h for 48h), Compression (tubigrip/bandage), Elevation
• Early mobilisation: Begin gentle ROM exercises as pain allows — improves healing
• Physiotherapy referral: For grade II-III sprains, tendon injuries, and significant strains
• Splintage/bracing: Aircast boot for significant ankle sprains; hinged knee brace for MCL injury

Pharmacological

• Paracetamol 1g QDS: First-line analgesia
• NSAIDs (ibuprofen 400mg TDS): After 48-72h (earlier use may impair healing — evidence mixed)
• Topical NSAIDs: Voltarol gel — effective for superficial soft tissue injuries with fewer systemic effects
• Codeine 30-60mg QDS: For moderate-severe pain short-term
• VTE prophylaxis: LMWH if lower limb immobilised in cast/boot and non-weight-bearing

Surgical/Interventional

• Achilles tendon repair: Surgical vs conservative (functional rehabilitation) — patient and injury dependent; discuss with orthopaedics
• ACL reconstruction: Typically delayed 6-12 weeks; for active patients with instability
• Fasciotomy: Emergency for compartment syndrome
• Meniscal repair/meniscectomy: Arthroscopic for locked knee or persistent symptoms

Referral Criteria

• Grade III ligament injuries — orthopaedic/sports medicine
• Tendon rupture — urgent orthopaedic referral
• Locked knee — urgent MRI and orthopaedic assessment
• ACL rupture — orthopaedic clinic (semi-urgent)
• Not improving at 6 weeks — physiotherapy reassessment or imaging

• Grade I sprains: Full recovery in 1-3 weeks
• Grade II sprains: Recovery in 4-8 weeks with rehabilitation
• Grade III sprains: Recovery in 3-6 months; some require surgery
• Achilles tendon rupture: 6-9 month recovery; re-rupture rate ~5% (surgical) to ~10% (conservative)
• ACL rupture: Return to sport typically 9-12 months post-reconstruction
• Chronic ankle instability: Develops in ~20% of ankle sprains — largely preventable with proper rehabilitation

Ottawa Ankle Rules — X-ray Required If

Achilles Tendon Rupture — Clinical Assessment