Radial Head Fractures

Radial head fractures are is very common in adults.  The radial head is the uppermost part of the radius bone which articulates with ulna at its proximal end through  the lesser sigmoid notch. It maintains contact with the ulna throughout forearm pronation and supination.

Radial head fracture may be isolated just to the radial head  or they may be part of a combined complex fracture injury pattern involving the other structures of the elbow, distal humerus, or forearm and wrist.

Relevant Anatomy

The elbow joint consists of 3 bones and 3 joints. The bones are the distal humerus , proximal ulna, and proximal radius. The ulnotrochlear joint is between the olecranon process of the ulna and the medial condyle of the humerus. This joint that allows only flexion/extension.

The radiocapitellar joint is between the radial head and the lateral condyle of the humerus. This joint is involved  both flexion and extension and forearm rotation. The radioulnar joint is between the radial head and the proximal ulna. This joint allows forearm rotation.

The elbow joint is supported by medial collateral ligament and lateral lateral collateral ligament, radial collateral, lateral ulnohumeral, and accessory collateral.

Mechanism of Injury to Radial Head

The vast majority of fractures of the radial head are sustained  due to a fall onto the outstretched  hand. The force is transmitted through  the radius to the elbow and the head of the radius is driven against  the capitellum.

The capitellem thus may also be injured.

Sometimes, valgus force to the elbow may result in radial head fracture and is frequently accompanied by a fracture  of the olecranon.  In  these  complex injuries,  it should  be remembered  that  the medial collateral ligament of the elbow is frequently torn. The rupture  of the collateral ligament on one side and the fracture of the radial head on the other render the elbow joint completely unstable.

Radial head fracture occurs in 20% of cases of elbow trauma, and about 33% of elbow fractures and dislocations include injury to the radial head and/or neck.

Presentation of Radial Head Fractures

There would be a history of fall on outstretched hand or blunt trauma. There would be localized swelling, tenderness, and decreased motion. Wrist should be examined for stability of the distal radioulnar joint. Elbow stability needs to be assessed with valgus stress at 30°.

A fracture of the head of radius presents with pain and swelling in the elbow region. There may be associated injuries to the structures in the neighborhood. These include distal humeral region, upper end of ulna. Radial head fractures are seen in quite a number of elbow dislocations.

Following injuries are associated with radial fractures and should be looked for

Associated Injuries

• Fractures of the capitellum
• Fractures of distal radius
• Dislocation of the distal radioulnar joint (Essex Lopresti Fracture)
• Rupture of medial collateral ligament
• Rupture of the triceps tendon
• Dislocation of elbow

Combination of radial head fracture, medial collateral ligament injury and coronoid process fracture is known as terrible triad of the elbow.

The diagnosis may be difficult to make on clinical examination. Radiographs are required to confirm the diagnosis. X-rays in the anteroposterior, lateral, and oblique planes of the elbow are usually sufficient to diagnose the fracture.

Lab Investigations

Generally not required for diagnosis making. May be needed as part of preparation for surgery.

Imaging

Mostly,  radial head fracture can be assessed adequately with anteroposterior and lateral views of elbow. The radial head must be aligned with the capitellum on all views. Sometimes, CT scanning of the elbow is useful to define fracture patterns

A radio-capitellar view may be helpful in doubtful cases (minimally or nondisplaced fractures). This view is taken in in neutral rotation & the x-ray tube is angled 45 degrees.

Alterrnatively modified radial-head capitellum view may be taken to identified undisplaced or minimally displaced fractures.

Modified Radial-Head Capitellum view

This view is taken with the posterior aspect of the supinated forearm in contact with the cassette and the elbow slightly flexed. The beam is directed 45 degrees mediolaterally.

CT scan helps in estimating the fracture size, degree of fragmentation, and displacement and give better understanding for planning for surgery.

Classification of Radial Head Fractures

Radial head fracture classification is described by Mason

Type I

The fracture consists of a simple split-wedge fragment  which may be displaced or undisplaced. It is also called chisel fracture.

Type II

In this fracture  pattern,  part  of the  head  and  neck  remain  intact. The portion  involved in the fracture is tilted and impacted.

Comminution  is variable.

Type III

A severely comminuted  fracture. The hallmark of this fracture is that no portion of the head or neck remains in continuity.

• IIIa – Fracture of the entire radial neck, with the head completely displaced from the shaft
• IIIb-  Articular fracture involving the entire head, consisting of more than two large fragments
• IIIc- Fracture with a tilted and impacted articular segment

Type IV

Fracture of the radial head with dislocation of the elbow joint

Treatment of Radial Head Fractures

Preservation of elbow flexion and extension, supination  and pronation are main goals of the treatment. In fracture dislocations of the elbow, the preservation of the stability of the elbow joint is  another objective.

Treatment options include closed fracture reduction with casting or early motion or open reduction with internal fixation, replacement, or resection.

Fractures with minimum displacement and angulation  are treated with non operative treatment.

Surgery is required if the fracture involves more than 33% of the articular surface, is angulated more than 30°, or is displaced more than 3 mm.

Following are indications for surgery for fractures of radial head-

• Major loose intra-articular fragments
• Displaced fractures that constitute a block the movements [examination is done under anesthesia]
• Displaced fractures of the radial head associated with fractures of the olecranon or with rupture of the ulnar collateral ligament, or with both
• Fractures of the radial  head  associated  with an injury  to the  distal  radio-ulnar joint  and  interosseous  membrane  rendering  the radius  axially unstable

Fixation options include minifragment plates and screws and Herbert screws.  If repair is not possible, excision of comminuted radial head fragments can be considered. If preoperative valgus intability is present medial collateral ligament is repaired.

If there is concomitant ipsilateral to the distal radioulnar joint injury [Essex Lopresti fracture], the distal radioulnar joint should be repaired.

Replacement surgery should be considered if the fracture is till annular ligament. After surgery, rehabilitation with range-of-motion exercises is begun as soon as the wound is healed. Union usually occurs within 6-8 weeks.

Mason classification guides treatment –

Type I Radial Head Fractures

These fractures are undisplaced or  displacement of the fracture is less than 2 mm. They do not need to be reduced and heal well by conservative treatment.

The patient can be treated in a simple arm sling or splint depending upon the soft tissue trauma. Active forearm mobilization followed by physiotherapy helps to restore usually good to excellent function.

Some patients might complain slight loss of extension.

If there is associated elbow dislocation,  the elbow should be splinted for a greater period and days, usually 3 weeks. Then limited motion is begun and weekly xrays should be done to monitor recurrent dislocation or subluxation of the joint. The care should focus on the dislocation rather than radial head fracture.

Type II Radial Head Fractures

This kind of injury is quite challenging for decision making regarding the treatment.  The treatment varies from  open reduction and internal fixation to excision. Patient profile and demands, associated injuries of the interosseous ligament or elbow dislocation can affect the decision.

If  There Is No Mechanical Block

Type II fractures that have no mechanical block to elbow motion can be treated similarly to type I. Close follow-up with weekly xrays is must. In difficult, a CT scan may be helpful in evaluating the case and executing the decision.

If  There Is Mechanical Block

The choice is made between excision and open reduction and fixation of the fracture.  In high-demand patient, preference should be given to open reduction and internal fixation. In the low-demand patient, excision may be better. In older patients excision should be considered as the bone quality does not favor a good fixation. If the condition of the patient does not permit excision it may as well be delayed.

Try should be to  preserve the radial head with open reduction and internal fixation when feasible and replace it with a prosthesis only when needed due to technical inability to obtain rigid fixation.

In elbow dislocation, it is preferable to preserve the radial head if possible.  Excision should be considered only as a last resort

If the radial head requires excision, repair of the lateral ligament complex is also required.

If the radial head cannot be saved and is excised, the potential for redislocation is high.

Type III Radial Head Fracture

These fractures are not repairable. These fractures possess extensive comminution and displacement and  early excision and replacement is the treatment of choice.

Just excision of the radial head is not advisable as it may result in proximal migration of the radius. Leading to  inferior  radioulnar  joint  disturbance  with pain and weakness of the wrist.

Although excision of the radial head might be con- templated as definitive treatment  for a comminuted fracture  if such a fracture  is in isolation, it cannot be considered an option if the fracture of the radial head is associated with rupture of the ulnar collateral ligament and instability of the elbow joint.

Mobilization should be begun early.

Complications of Radial Head Fractures

Neurovascular Injury

Injury to nerve or vessel generally occurs in severe elbow injuries and is rare in case of isolated radial head fracture. Arterial injury is an acute emergency. Neural injury management would vary with whether the injury is open or close.

Compartment Syndrome

A severe injury to elbow can lead to compartment syndrome. The compartment syndrome is an emergency which requires intensive monitoring. Fasciotomy may be required in the cases which do not resolve.

Infection

Infection can be an early or late and usually requires intravenous antibiotics. Irrigation and debridement may also be required. Management is on individual basis and depends if fracture is treated by closed method or open.

Persistent Pain

It may be due to  hardware, intra-articular cartilage injury and posttraumatic arthritis, adhesions, malalignment, or associated nerve or muscle injuries.

Nonunion and Malunion

Nonunion after radial head fracture is usually due to poor biomechanics, poor initial fracture characteristics, soft tissue damage.  An open injury or an extensive periosteal stripping predisposes to slow healing. Treatment of nonunion requires internal fixation or radial head excision or replacement.

Restriction of Movement

Stiffness is common after elbow injuries, especially if they have been immobilized. Motion is difficult to recover  and as far as possible, early mobilization should be initiated. Closed fracture reduction and casting often has associated high rates of stiffness.

Synostosis

After radial head fracture a disabling complication because it limits motion, especially rotation of the forearm. Risks include closed head injury, surgical delay longer than 2 weeks, and penetration of the interosseous membrane  during surgery by instruments or implants. Treatment by resection with an interposition spacer restores motion in about 50% of patients.

Proximal Migration

Because relations of ulna and radius bone alter with proximal migration of radius, it results in deformities at wrist. One of the major factors that prevent proximal migration is the interosseous ligament, also known as interosseous membrane. It is a complex structure that connects radius and ulna in their entire length

Interosseous ligaments shares all the load transferred when radial head is not present. It might get stretched and may migrate proximally.