Volkmann Contracture

Etiology

Volkmann ischemic contracture is classically associated with a supracondylar fracture of the humerus. However, any fracture of the arm or elbow may result in this deformity. The key precipitating event in supracondylar fractures of the humerus is ischemia of the forearm due to acute compartment syndrome.[3] Compartment syndrome is a condition in which there is an increase in the intra-fascial pressure of any closed compartment in the body. This may occur due to two basic reasons: a decrease in compartment size or an increase in the volume of the compartment described as intrinsic or extrinsic compartment syndrome. Thus, essentially it can be said that any cause of compartment syndrome may potentially result in Volkmann ischemic contracture. Causes of compartment syndrome include:

1. Tight bandages and dressings
2. Animal bites
3. Burns
4. Intensive and excessive exercises
5. Muscle hypertrophy
6. Neoplasms
7. Bleeding into a closed compartment (injury to a vessel, congenital or acquired disorder)
8. Injections in the forearm
9. Surgery on the forearm

Volkmann ischemic contracture is also described as a sequela of acute arterial insufficiency of the limbs. Emboli lodging in the arterial vasculature can also result in ischemia of the muscles resulting in limb contractures.

Epidemiology

Volkmann ischemic contracture is a relatively rare condition. It most commonly presents after pediatric upper limb trauma. In one study, the incidence of Volkmann contracture was 0.105% of all orthopedic cases, with the majority of cases being males in their second and third decade of life.[4] Another study reviewed children admitted to the hospital with upper extremity long bone fractures over 13 years. Thirty-three of these patients had a supracondylar fracture, out of which 3 developed Volkmann ischemic contracture. Subgroup analysis later showed that ipsilateral displaced extension type supracondylar humerus fractures or displaced forearm fractures had a prevalence of 33% for Volkmann contracture. This highlights the importance of keeping a vigilant eye for signs and symptoms of compartment syndrome in patients with supracondylar humerus fractures, especially those displaced.[5]

Pathophysiology

Volkmann contracture develops when there is sustained ischemic damage to the muscles. Diminished blood flow to the forearm, causing ischemia, may be due to increased compartmental pressures or acute arterial emboli.[6] Intracompartmental pressures of greater than 30 mmHg (normal: less than 10 mmHg) significantly impair the arterial circulation and are indicative of compartment syndrome.[7] Contractures eventually develop due to prolonged myonecrosis, which stimulates fibroblastic proliferation, shortening of the cicatrix, and myotendinous adhesions, resulting in a fibrotic pull on the wrists and fingers.[8]

History and Physical

Patients with Volkmann ischemic contracture have a typical history and physical examination. A displaced supracondylar fracture of the humerus is the most commonly associated injury with Volkmann contracture of the forearm. The key signs and symptoms of compartment syndrome develop well before the actual contracture and fibrosis of the muscles. Pain is the initial symptom, followed by pallor, pulselessness, paresthesias, and paralysis: commonly referred to as the 5 Ps of compartment syndrome.[9] Pain is also exacerbated by passive extension of the hands and fingers of the affected limb. This is one of the earliest signs of compartment syndrome and should prompt quick investigations into the possible development of Volkmann contracture. The palpation of the forearm also shows the firmness of tissues. Palpating the radial artery’s pulse volume and character also yields important clues to the degree of compartment syndrome. Therefore, a proper history and physical examination are key to timely diagnosing and preventing Volkmann contracture.

Volkmann contracture can be classified according to the Tsuge system into three grades: mild, moderate, and severe.[10][11]

Mild

This is a localized type of contracture in which only parts of the flexor digitorum profundus are affected. It commonly presents as flexion of a limited number of fingers, 2 or 3, usually involving the middle and ring fingers. Sensory loss is minimal, if at all present.

Moderate

This is a classic type of contracture in which flexor digitorum profundus and flexor pollicis longus are primarily involved. Superficial muscles such as flexor digitorum superficialis, flexor carpi ulnaris, and flexor carpi radialis may also be affected. Fibrosis of the mentioned muscles leads to a typical claw hand picture, which presents as flexion of all five digits as well as the wrist. Sensory impairment in regions of the median and the ulnar nerve is also common.

Severe

This type of contracture develops in extreme cases and presents as the involvement of both flexors and extensors. This results in severely distorted contractures with pronounced sensory deficits. Long-standing moderate Volkmann contractures have the potential of eventually developing into severe Volkmann contractures.

Evaluation

Volkmann contracture typically presents as a classical picture, making the diagnosis easy and justifiable with the help of history and physical examination. In fact, most cases do not even require lab investigations for reaching a diagnosis. However, if needed, acute compartment syndrome may be investigated with creatine phosphokinase (CPK), blood urea nitrogen (BUN), creatinine, serum electrolytes, serum calcium, urinalysis, and urine myoglobin. Abnormalities in any of the above investigations can suggest compartment syndrome. Coagulation studies may also be warranted if a bleeding disorder is considered a potential cause of compartment syndrome. A complete blood picture will also help rule out anemia, which can potentiate anoxia in the osteofascial compartment.

Measuring the intracompartmental pressure of the osteofascial compartment is the standard of diagnosis when the history and physical examination is nonconclusive. It may also help confirm the findings of clinical assessment. Nevertheless, care must be taken not to exclude compartment syndrome based on a single normal reading.[12] There are many methods of measuring intra-compartmental pressures; among them, the Stryker tonometer gives relatively accurate readings. A compartmental pressure of greater than 30 to 40 mmHg is considered abnormal and warrants immediate fasciotomy, as delays of even a few hours might prove detrimental to the prognosis.[13] Near-infrared Spectroscopy (NIRS) can also aid the assessment and management of acute compartment syndrome. The wide use of NIRS is limited due to its cost and limited availability of sensors, despite proving to be a reliable noninvasive investigation for Volkmann ischemic contracture.[14]

Imaging studies such as x-rays, magnetic resonance imaging scans (MRIs), and computed tomography (CT) scans may prove to be supportive in the diagnosis of Volkmann ischemic contracture but are not considered first-line investigations. X-rays may especially be helpful in identifying displaced supracondylar fractures of the humerus. CT scan and MRI may also have a role in narrowing down the differential diagnosis of compartment syndrome unrelated to fractures of the upper limb. An ultrasound may also help exclude the differential diagnosis of acute compartment syndrome.

Treatment / Management

The first and foremost step in any suspected case of compartment syndrome or early Volkmann contracture is the removal of all external dressings, splints, or casts. This meager but crucial step might halt the development of Volkmann contracture if extrinsic compartment syndrome is the prime culprit. It is shown that casts may restrict compartment expansion by up to 40% and should always be removed, a step that reduces pressure elevation by about 40 to 60%.[15]  This also opens up the field of view to perform necessary investigations and physical examinations. Although elevation of the limb decreases swelling, it is not recommended beyond the level of the heart as it can also reduce limb perfusion, thus increasing the risk of ischemia. Allowing relative hypertension and correcting anemia can also slow down the progression of acute compartment syndrome. Analgesics may be prescribed according to the intensity of pain. However, care must be taken not to get complacent because of the relief of symptoms.(B3)

The primary emergency treatment for acute compartment syndrome leading to Volkmann contracture is emergency fasciotomy. It is generally agreed that intracompartmental pressures above 30 to 40 mmHg necessitate this. Decompression can be achieved by volar or dorsal approach, both of which release compartmental pressure. The median nerve needs decompression throughout its course, especially in the high-risk areas (deep to lacertus fibrosus, in the carpal tunnel, and between the heads of pronator teres).[16](B3)

Physicians must also be wary of myoglobinuria that is a result of prolonged ischemia. Reperfusion syndrome can cause significant systemic abnormalities leading to multiorgan failure.[17] Adequate hydration, monitoring of arterial blood gases, renal function tests, and managing of electrolyte disturbances is required.

If Volkmann contracture has already developed, the treatment approach depends on the degree of contracture. Mild Volkmann contracture may be treated with physical therapy, dynamic splinting along with tendon lengthening, and slide procedures. These are associated with a relatively favorable outcome. Moderate contractures may require tendon slide, neurolysis, and extensor transfer operations. Severe contractures affecting both extensor and flexor groups necessitate extensive and radical debridement of the scar tissue. After debridement, tendon transfer procedures may be used to regain motion of the digits. Brachioradialis is often used to regain the movement of the thumb by transferring the tendon to flexor pollicis longus. Extensor carpi radialis longus is transferred to flexor digitorum profundus to regain finger flexion. Free muscle transplantation may also be needed if the belly of the muscle is necrosed. A necrotic muscle can be identified by its color, contractility, consistency, and capacity to bleed.[18]

Differential Diagnosis

Volkmann contracture needs to be differentiated from:

• Dupuytren contracture
• Pseudo Volkmann contracture

Pseudo Volkmann contracture is defined as the inability to fully extend fingers, because of mechanical entrapment, in patients with forearm fractures. It is important to note that signs and symptoms of ischemia are absent in pseudo-Volkmann contracture.[19] This is a relatively rare condition that may be seen in the pediatric age group due to tethering of flexor digitorum profundus to a fractured ulna.[20]

Dupuytren's contracture is a progressive condition characterized by permanent flexion of one or more fingers. The exact etiology is not fully known; however, risk factors include chronic liver disease, alcoholism, smoking, and prior trauma. Dupuytren's contracture begins as thickening nodules in the palm, later progressing to restriction of finger motion.

Some literature does not limit the term 'Volkmann contracture' to just the presentation in the hand.[8] However, most literature exclusively mentions Volkmann contracture as the ischemic fibrosis of anterior forearm muscles. For the purpose of this writing, we will stay limited to its presentation in the hand.

Prognosis

The outcome of fasciotomy for acute compartment syndrome leading to Volkmann contracture depends on the duration and intensity of compartment syndrome. Prompt fasciotomy, i.e., within 4 hours, leads to minimal sequelae. The prognosis of developed Volkmann contracture varies greatly from case to case. It is, however, observed that nearly all patients suffering from a contracture during childhood end up with a relatively short limb.[21] Functioning free muscle transfer (FFMT) results in substantial improvements in hand function; in contrast, tendon lengthening causes recurrence of contractures in many cases. Generally speaking, tenolysis, neurolysis, tendon transfer procedure, and the removal of necrotic muscle produce good hand function in those who have sufficient muscle remaining.[21]

Complications

Complications of the treatment for Volkmann contracture vary from procedure to procedure. Common complications of the fasciotomy wound include altered sensations (77%), dry and scaly skin (40%), pruritus (33%), and discolored wounds (30%).[21] The unsightly appearance of the wounds is also a cause of significant distress to the patients, with 23% of patients altering their behavior to hide their scars.

Over tensioning and under tensioning is a potential complication for tendon transfer surgery.[22] These may result even with the most skilled hands as the knot used may loosen or slip. Hematoma formation and wound dehiscence may be a cause for postoperative worry when flexor origin slide surgery is performed. Functional free muscle transfer surgery is also associated with complications. Flap loss, infection, scarring, and tendon adhesion formations being the most commonly occurring.