Volkmann's Ischaemic Contracture — Forearm Compartment Syndrome, Fasciotomy and the Established Claw

Volkmann's ischaemic contracture (VIC) is a claw-like deformity of the hand caused by death and fibrosis of forearm muscles after prolonged ischaemia. StatPearls describes it as a permanent flexion deformity at the wrist and fingers resulting from permanent shortening of the forearm flexor group. It is named after the German surgeon Richard von Volkmann, who in 1881 attributed irreversible flexor contractures to ischaemia from overly tight bandages.

Today it is understood as the end stage of an untreated acute compartment syndrome (ACS) of the forearm. Swollen muscle inside an unyielding osteofascial envelope raises tissue pressure until capillary perfusion fails; muscle and nerve then infarct, and the dead muscle is replaced by shortening scar. The acute phase is often called Volkmann's ischaemia; the late deformity is the contracture.

Anything that raises pressure inside the forearm compartments — or shrinks them — can trigger the ischaemic cascade: fractures with bleeding and oedema, tight circumferential bandages or casts, crush injury, burns (including high-voltage electrical burns), reperfusion after arterial repair, and bleeding disorders.

The supracondylar humerus fracture is the textbook link. It is the commonest elbow fracture in children, accounting for 60–70% of paediatric elbow fractures, and usually follows a fall on the outstretched hand with the elbow extended. Displaced fractures can injure the brachial artery: vascular compromise is reported in roughly 3–19% of cases, and an absent radial pulse in 6–20% of all supracondylar fractures.

• Risk factors for compartment syndrome after a supracondylar fracture: Gartland type III (completely displaced) fracture, pre-operative median nerve palsy, floating elbow (ipsilateral forearm fracture), delayed treatment of a limb with vascular compromise, and a long-arm cast applied in hyperflexion.
• Compartment syndrome may develop 12 to 24 hours after the injury, from vascular injury plus primary swelling.
• Avoid circumferential casting and extreme elbow flexion while treating these fractures.

The forearm has three main compartments: the volar (flexor) compartment with superficial and deep flexors, the dorsal (extensor) compartment, and the mobile wad (brachioradialis, extensor carpi radialis longus and brevis). Pronator quadratus is sometimes described as a fourth compartment.

During ischaemia the deep flexor compartment is the most vulnerable — flexor digitorum profundus (FDP) and flexor pollicis longus (FPL). Lying against the bones and interosseous membrane, it has the least room to expand and is the first and most severely affected. Damage is worst in the middle of the muscle belly and fades towards its edges — Seddon's ellipsoid infarct. With longer or more severe ischaemia the superficial flexors, pronator teres and wrist flexors die too; in the worst cases even the extensors.

Nerves are damaged twice: first by the ischaemia itself, later by fibrous strangulation within the scarred muscle. The median nerve is the most susceptible because it runs between the superficial and deep flexor layers, right in the zone of maximal ischaemia; the ulnar nerve is involved in more severe cases.

ACS is a clinical diagnosis. The classic teaching is the five Ps — pain, pallor, pulselessness, paralysis and paraesthesia — but they do not appear together, and waiting for all five means waiting for necrosis.

On examination the forearm may feel firm and 'wooden' on deep palpation. Pain is subjective and hard to judge in unconscious, sedated or very young patients; this is where compartment pressure measurement helps.

Pressure is measured with a transducer-linked catheter inserted into the compartment (within 5 cm of the injury zone). The normal resting intracompartmental pressure is about 10 mmHg. Early studies proposed absolute cut-offs of 30, 45 or 50 mmHg; 30 mmHg became the most quoted.

Whitesides introduced the idea that the damaging pressure depends on the patient's own perfusion pressure, so a hypotensive patient tolerates less. McQueen and Court-Brown found that a ΔP threshold of 30 mmHg led to no missed cases and no unnecessary fasciotomies. The delta pressure is therefore preferred to any single absolute number.

1. Remove every constriction — split and spread the cast and padding down to the skin.
2. Keep the limb at heart level, not elevated — elevation lowers arterial inflow further.
3. Maintain normal blood pressure, give oxygen and IV fluids; hypotension worsens perfusion.
4. In a supracondylar fracture, reduce and stabilise the fracture and reduce elbow flexion; re-check the circulation.
5. If signs persist → emergency fasciotomy of all involved compartments.

Forearm fasciotomy: a volar (Henry-type) incision from above the elbow to the wrist crease decompresses the flexor compartments and the mobile wad; median nerve decompression is always performed at the same time. If the dorsal compartment remains tight, a straight dorsal incision (Thompson's approach) is added.

• Wounds are left open; a second look and debridement at 48–72 hours is usual.
• Delayed primary closure or skin grafting at 7–10 days once swelling settles.
• Watch for rhabdomyolysis and acute kidney injury — keep urine output above 0.5 mL/kg/h.

Once muscle has infarcted and fibrosed, the patient no longer has pain — they have deformity and loss of function. The deformity progresses over weeks to months and then stabilises; in children it keeps worsening until skeletal maturity, because scarred muscle cannot lengthen as fast as bone grows, and the affected limb ends up shorter.

Typical upper-limb deformity (Botte 1998): elbow flexion, forearm pronation, wrist flexion, thumb flexion and adduction, extension at the metacarpophalangeal joints and flexion at the interphalangeal joints — the 'ischaemic claw'.

Sensory loss in the median (and in severe cases ulnar) distribution, intrinsic muscle weakness and trophic skin changes accompany the moderate and severe forms. A pseudo-Volkmann contracture — FDP or FPL tethered by scar to a radius or ulna fracture — mimics a mild contracture; the muscles look normal at surgery and a simple tenolysis corrects it. MRI helps tell the two apart.

The Holden classification describes the level of injury instead: type I — injury proximal to the ischaemic zone (typically a brachial artery injury at the elbow); type II — injury directly at the zone of ischaemia and contracture (for example a forearm fracture or tight bandage). Series often combine Holden and Tsuge to describe each patient fully.

In the muscle slide, the origins of the flexor-pronator mass are detached from the medial epicondyle, ulna, interosseous membrane and radius and allowed to slide distally by a few centimetres. This corrects the contracture without shortening the muscle's resting length, so remaining muscle power is preserved — an advantage over tendon lengthening, which weakens an already weak muscle. In one series of 19 moderate contractures, 15 achieved good function after a Max Page slide.

The gracilis is preferred for free functional transfer because its length and excursion (about 12 cm) match the excursion needed for finger flexion. Tendon lengthening alone tends to give recurrent contracture, especially in growing children.

• Child with a supracondylar fracture in an above-elbow cast now has severe pain on passive finger extension → first step: remove/split the cast; if no relief → fasciotomy.
• Earliest sign of compartment syndrome → pain on passive stretch (pain out of proportion); pulselessness is late.
• Muscle most affected → FDP (deep flexor compartment, with FPL); nerve most affected → median.
• Pressure indication for fasciotomy → ΔP (diastolic − compartment) ≤ 30 mmHg, or an absolute pressure above about 30 mmHg.
• Volkmann's sign → fingers extend only with the wrist flexed.
• Operation for moderate contracture → Max Page muscle slide; for severe → free functional (gracilis) muscle transfer.

Revise the neighbouring nerve injuries — the upper-trunk brachial plexus lesion in Erb's palsy and the claw hand of lower-trunk injuries — and the physiology of muscle ischaemia. For past papers, see the NEET PG orthopaedics PYQs.