Complications of Fractures

💥 Complications of Fractures

Compartment syndrome, fat embolism, AVN, CRPS, non-union, and infection — the high-yield complications every surgical trainee must master.

Acute Compartment Syndrome

Acute compartment syndrome (ACS) is a surgical emergency in which pressure within a closed fascial compartment rises to a level that compromises capillary perfusion, causing ischaemia and ultimately irreversible muscle and nerve damage if not treated within hours. It is one of the most important diagnoses not to miss in orthopaedic surgery.

Core Concept — Do Not Wait for Pulse Loss

Absent pulse is a late and catastrophic sign indicating arterial occlusion — permanent damage is already done. The diagnosis must be made and acted upon at the earliest signs: pain out of proportion and pain on passive stretch of the muscles in that compartment. Waiting for the classic “6 Ps” in full is dangerous clinical practice.

Pathophysiology

Normal compartment pressure: 0–8 mmHg. Capillary perfusion requires a pressure gradient between mean arterial pressure and compartment pressure. When compartment pressure rises:

Venous outflow obstructed first → venous hypertension → interstitial oedema → further pressure rise (vicious cycle)
Capillary perfusion pressure falls below compartment pressure → local ischaemia
Nerve ischaemia: within 30 minutes → paraesthesia
Muscle ischaemia: irreversible damage within 4–6 hours (Volkmann’s ischaemic contracture)
Arterial flow compromise: very late sign (compartment pressure must approach diastolic BP)

🔴 Threshold for Fasciotomy

Absolute threshold: Compartment pressure >30 mmHg

Delta P (ΔP) method: Diastolic BP − compartment pressure <30 mmHg → fasciotomy regardless of absolute pressure. More physiologically relevant in hypotensive patients.

Example: BP 80/50, compartment pressure 25 mmHg → ΔP = 50 − 25 = 25 mmHg → fasciotomy indicated

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🟢 Clinical Diagnosis

Do not wait for pressure measurement if clinical signs are clear. Pressure measurement is useful in:

Unconscious / uncooperative patients
Regional anaesthesia masking symptoms
Equivocal clinical picture

Use Stryker STIC device or arterial line manometer. Measure in each compartment at multiple sites.

The 6 Ps — In Order of Progression

Earliest

Pain — out of proportion to the injury

Severe, burning, unrelenting pain that seems excessive for the mechanism. Increasing analgesia requirement. Act on this sign.

Early

Pain on Passive Stretch

Passively extending the toes/fingers stretches the ischaemic muscles in the relevant compartment → severe pain. Most sensitive early sign alongside disproportionate pain. This is your trigger.

Early

Pressure — tense, woody compartment

Compartment feels tense and hard on palpation — like wood. Skin may appear shiny and taut.

Intermediate

Paraesthesia — nerve ischaemia

Tingling and numbness in the distribution of nerves passing through the compartment. Nerve is ischaemic — irreversible damage developing.

Late

Paralysis — muscle death

Motor loss indicates significant muscle ischaemia. Likely irreversible at this stage without immediate fasciotomy. Volkmann’s contracture developing.

Very Late

Pulselessness — do NOT wait for this

Absent pulse = arterial occlusion = compartment pressure ≈ diastolic BP. At this point, irreversible ischaemic damage is almost certain. Fasciotomy is still needed but outcome is poor.

Common Sites & Compartments

Site	No. of Compartments	Compartments	Common Cause
Leg	4	Anterior, lateral, deep posterior, superficial posterior	Tibial fracture, crush, reperfusion. Anterior compartment most commonly affected.
Forearm	3	Volar (flexor), dorsal (extensor), mobile wad	Both-bone forearm fracture, distal radius fracture, supracondylar fracture (children)
Thigh	3	Anterior, posterior, medial (adductor)	Femoral fracture, crush injury, massive haematoma
Foot	9	Multiple (medial, central, lateral, interosseous × 4, calcaneal)	Lisfranc injury, calcaneal fracture, crush
Hand	10	4 dorsal interosseous, 3 palmar interosseous, thenar, hypothenar, adductor pollicis	Metacarpal fractures, burns, injection injury
Gluteal	3	Tensor fasciae latae, gluteus medius/minimus, gluteus maximus	Prolonged lithotomy position, pelvic fracture, trauma

Causes of Acute Compartment Syndrome

Increased Content	Decreased Container Size
Fractures (especially tibial shaft, supracondylar)	Tight cast / backslab (too early, too circular)
Crush injury	Tight dressings / bandages
Burns (circumferential)	Closure of fascial defect
Reperfusion injury (post vascular repair)	External compression (unconscious patient)
Intravenous infiltration / extravasation
Bleeding into compartment (anticoagulated patient)
Intense exercise (exertional compartment syndrome)

Management — Emergency Fasciotomy

Release ALL compartments — incomplete fasciotomy is a common error
Leg: Two-incision technique — lateral (anterior + lateral compartments) and medial (deep + superficial posterior compartments). Full-length skin incisions.
Forearm: Volar Henry approach incision extended through carpal tunnel; dorsal incision if needed
Do not close primarily — leave open, cover with dressings / VAC. Return to theatre at 48–72 hours for reassessment; split skin graft if needed.
After decompression: expect reperfusion injury — myoglobinuria, hyperkalaemia, acute kidney injury (rhabdomyolysis). Aggressive IV fluids to maintain urine output >200 mL/hr.
Timing: Outcomes excellent if within 6 hours. Poor if >12 hours. Fasciotomy may still be required at >12 hours to limit ongoing damage even if outcome compromised.

Pitfalls & Special Situations

Epidural / regional anaesthesia: Masks pain — maintain vigilance, use pressure measurement
Children: Supracondylar fracture → anterior compartment forearm ACS (Volkmann’s). The 3 As: Agitation, Anxiety, increasing Analgesia requirement
Cast too tight: Bivalve cast + remove all padding as first step — if no improvement → fasciotomy
Chronic exertional: Occurs during exercise, resolves with rest. Diagnosed by exercise pressure measurement. Treatment: fasciotomy electively.

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