MyPACS.net: Radiology Teaching Files > Case 8028820

never visited ELBOW INJURY
Contributed by: Bertram Newmark, Radiologist, VCOM, Virginia, USA.
Patient: female
History:
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Findings: Trauma to R elbow. Presents to ER.
Diagnosis: Longitudinal fracture through the lateral aspect of the radial head, with minimal depression. No other fracture or dislocation is seen.
Discussion: History of the Procedure: Radial head and neck fractures and dislocations have been treated by closed and open methods. Early attempts at closed treatment with casting resulted in stiffness and loss of function in the elbow. Consequently, treatment has evolved so that only patients with fractures stable enough to allow early motion undergo closed treatment, while essentially all other patients are treated with a form of surgical treatment. Surgical methods have included excision of the fracture fragments, replacement, and internal fixation. Problems with proximal radial migration, especially with excision but also with replacement, and problems with the replacement implants has led to the belief that anatomic reduction and internal fixation is currently the treatment of choice for unstable and displaced radial head and neck fractures and dislocations.

Problem: Radial head fractures and dislocations are traumatic injuries that require adequate treatment to prevent disability from stiffness, deformity, posttraumatic arthritis, nerve damage, or other serious complications. Radial head fractures and dislocations may be isolated just to the radial head (and neck) and the lateral elbow (and proximal forearm), 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.


Frequency: The radial head is fractured in about 20% of cases of elbow trauma, and about 33% of elbow fractures and dislocations include injury to the radial head and/or neck.

Etiology: Except for the occurrence of congenital radial head dislocations, which are by definition congenital, radial head fractures and dislocations are the result of trauma, usually from a fall on the outstretched arm with the force of impact transmitted up the hand through the wrist and forearm to the radial head, which is forced into the capitellum. Recognizing the congenital radial head dislocation, where the radial head is larger and rounder than expected, is important because operative treatment to reduce a congenital radial head dislocation is not indicated (see Image 1).


Pathophysiology: See Relevant Anatomy. The radial head is intra-articular, so anatomic reduction of bone fragments is necessary to minimize the risks of lateral posttraumatic arthritis from mechanical grinding. The intra-articular position also means that soft tissue attachments to the most proximal portion of the bone are limited, so fractured fragments frequently lose their blood supply, resulting in avascular necrosis and potential nonunion. Luckily, the radial head mostly acts as a spacer preventing proximal migration of the radius, and as long as it maintains its structural support, the patient may do well even if the bone dies
Medical therapy: Treatment options for radial head fractures or dislocations include closed reduction with casting or early motion or open reduction with internal fixation, replacement, or resection. Closed reduction and casting often has associated high rates of stiffness, and closed reduction and early motion may still have high rates of nonunion and malunion in comminuted or unstable fractures, resulting in generally poor functional results. Open treatment (including internal fixation, replacement, or excision depending on the fracture) is associated with better long-term function.

The condition of the soft tissues is as important as the condition of the bone in determining the eventual functional outcome (see Image 4). Schatzker's general observation concerning fracture care is especially relevant for elbow injuries, "long term disability following a fracture is almost never the result of damage to the bone. It is the result of damage to the soft tissues and stiffness of neighboring joints" (Schatzker, 1987).

An isolated radial head dislocation is almost always treated with closed reduction and early motion. If closed reduction cannot be achieved, then open reduction is indicated (see Image 5). Congenital radial head dislocations do not require treatment (see Image 1).

For isolated radial head fractures, the Mason classification guides treatment. Nonsurgical treatment of radial head fractures is indicated if minimal displacement, minimal angulation, and minimal head involvement are noted (see Image 6). Early motion with a functional brace is encouraged to minimize elbow stiffness. Adequate follow-up is essential to be sure late displacement is not missed. (If displacement occurs, operative intervention is usually indicated.)

In the Mason classification, the fracture is type I if it is undisplaced, type II if a single fragment is displaced, and type III if it is comminuted. Type I (nondisplaced) is generally treated nonoperatively. Type II may be treated nonoperatively if the displacement is minimal. The rule of threes is used. Nonsurgical treatment can be considered if the fracture involves less than one third of the articular surface, less than 30 of angulation, and if displacement is less than 3 mm. Type III fractures usually require operative intervention but may occasionally be treated closed with early motion if the radial head is not reconstructible. If a mechanical block to motion is present, then nonsurgical treatment cannot be used.

Fracture-dislocations of the radial head can rarely be treated with closed reduction and splinting, but better results are expected in most cases with operative stabilization and early motion.

Patients whose medical condition is too unstable to allow safe surgery when surgery is indicated can also be treated with splinting followed by early motion, but the prognosis is guarded for achieving optimal function.

Surgical therapy: Surgical treatment is indicated for all unstable radial head (and neck) fractures and dislocations. As described above, the rule of threes can be used for determining the need for surgical intervention. 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. A mechanical block to motion always requires open treatment to remove the blocking bone or osteochondral fragment or fragments. Open fractures are also surgical emergencies. They require surgical irrigation and debridement in an operating room with appropriate antibiotics even if the wound is small. At the same time, immediate stabilization of the bone injury is also performed.

Monteggia fracture-dislocations are a special type of radial head injury. Classically, Monteggia fractures are ulna fractures in the proximal one third with associated radial head dislocation. Instead of the radial head dislocation, the radial head or neck may be fractured as an equivalent injury (see Images 2-3 and Images 14-16). Classification is listed in the following table.

Classification of Monteggia fracture-dislocations

Type Description Equivalent(s) %
Type IAnterior dislocation of the radial head and anterior angulation of the ulna fracture Radial head or neck fracture instead of dislocation 60
Type IIPosterior dislocation of the radial head and posterior angulation of the ulna fracture Posterior elbow dislocation
Radial head or neck fracture instead of dislocation
105
Type IIILateral dislocation of the radial head with proximal ulna fracture Radial head or neck fracture instead of dislocation 20
Type IVAnterior dislocation of the radialhead and proximal shafts of both bones fractured at same level Radial head or neck fracture instead of dislocation 5

The injury pattern is similar to both bone forearm fractures. Monteggia fracture-dislocations are included here because of the importance of not missing either injury. The isolated injuries (radial head dislocation by itself or ulna [nightstick] fracture by itself) are often treated by closed treatment with good results, but the combined injury can almost never be treated by closed methods if good results are expected. Appropriate treatment requires diagnosing both (see Imaging Studies and Images 2-3).

Floating elbow injures are another special case that can include radial head injury. Floating elbow injuries include associated ipsilateral forearm and humerus fractures. They are severe high-energy injuries. The best outcome almost always requires fixation at both levels. Standard fixation methods for the individual fractures are used (see Image 7). Surgical treatment options include open reduction internal fixation with plates and screws, excision of fragments, or radial head replacement.

References: History of the Procedure: Radial head and neck fractures and dislocations have been treated by closed and open methods. Early attempts at closed treatment with casting resulted in stiffness and loss of function in the elbow. Consequently, treatment has evolved so that only patients with fractures stable enough to allow early motion undergo closed treatment, while essentially all other patients are treated with a form of surgical treatment. Surgical methods have included excision of the fracture fragments, replacement, and internal fixation. Problems with proximal radial migration, especially with excision but also with replacement, and problems with the replacement implants has led to the belief that anatomic reduction and internal fixation is currently the treatment of choice for unstable and displaced radial head and neck fractures and dislocations.

Problem: Radial head fractures and dislocations are traumatic injuries that require adequate treatment to prevent disability from stiffness, deformity, posttraumatic arthritis, nerve damage, or other serious complications. Radial head fractures and dislocations may be isolated just to the radial head (and neck) and the lateral elbow (and proximal forearm), 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.


Frequency: The radial head is fractured in about 20% of cases of elbow trauma, and about 33% of elbow fractures and dislocations include injury to the radial head and/or neck.

Etiology: Except for the occurrence of congenital radial head dislocations, which are by definition congenital, radial head fractures and dislocations are the result of trauma, usually from a fall on the outstretched arm with the force of impact transmitted up the hand through the wrist and forearm to the radial head, which is forced into the capitellum. Recognizing the congenital radial head dislocation, where the radial head is larger and rounder than expected, is important because operative treatment to reduce a congenital radial head dislocation is not indicated (see Image 1).


Pathophysiology: See Relevant Anatomy. The radial head is intra-articular, so anatomic reduction of bone fragments is necessary to minimize the risks of lateral posttraumatic arthritis from mechanical grinding. The intra-articular position also means that soft tissue attachments to the most proximal portion of the bone are limited, so fractured fragments frequently lose their blood supply, resulting in avascular necrosis and potential nonunion. Luckily, the radial head mostly acts as a spacer preventing proximal migration of the radius, and as long as it maintains its structural support, the patient may do well even if the bone dies
Medical therapy: Treatment options for radial head fractures or dislocations include closed reduction with casting or early motion or open reduction with internal fixation, replacement, or resection. Closed reduction and casting often has associated high rates of stiffness, and closed reduction and early motion may still have high rates of nonunion and malunion in comminuted or unstable fractures, resulting in generally poor functional results. Open treatment (including internal fixation, replacement, or excision depending on the fracture) is associated with better long-term function.

The condition of the soft tissues is as important as the condition of the bone in determining the eventual functional outcome (see Image 4). Schatzker's general observation concerning fracture care is especially relevant for elbow injuries, "long term disability following a fracture is almost never the result of damage to the bone. It is the result of damage to the soft tissues and stiffness of neighboring joints" (Schatzker, 1987).

An isolated radial head dislocation is almost always treated with closed reduction and early motion. If closed reduction cannot be achieved, then open reduction is indicated (see Image 5). Congenital radial head dislocations do not require treatment (see Image 1).

For isolated radial head fractures, the Mason classification guides treatment. Nonsurgical treatment of radial head fractures is indicated if minimal displacement, minimal angulation, and minimal head involvement are noted (see Image 6). Early motion with a functional brace is encouraged to minimize elbow stiffness. Adequate follow-up is essential to be sure late displacement is not missed. (If displacement occurs, operative intervention is usually indicated.)

In the Mason classification, the fracture is type I if it is undisplaced, type II if a single fragment is displaced, and type III if it is comminuted. Type I (nondisplaced) is generally treated nonoperatively. Type II may be treated nonoperatively if the displacement is minimal. The rule of threes is used. Nonsurgical treatment can be considered if the fracture involves less than one third of the articular surface, less than 30 of angulation, and if displacement is less than 3 mm. Type III fractures usually require operative intervention but may occasionally be treated closed with early motion if the radial head is not reconstructible. If a mechanical block to motion is present, then nonsurgical treatment cannot be used.

Fracture-dislocations of the radial head can rarely be treated with closed reduction and splinting, but better results are expected in most cases with operative stabilization and early motion.

Patients whose medical condition is too unstable to allow safe surgery when surgery is indicated can also be treated with splinting followed by early motion, but the prognosis is guarded for achieving optimal function.

Surgical therapy: Surgical treatment is indicated for all unstable radial head (and neck) fractures and dislocations. As described above, the rule of threes can be used for determining the need for surgical intervention. 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. A mechanical block to motion always requires open treatment to remove the blocking bone or osteochondral fragment or fragments. Open fractures are also surgical emergencies. They require surgical irrigation and debridement in an operating room with appropriate antibiotics even if the wound is small. At the same time, immediate stabilization of the bone injury is also performed.

Monteggia fracture-dislocations are a special type of radial head injury. Classically, Monteggia fractures are ulna fractures in the proximal one third with associated radial head dislocation. Instead of the radial head dislocation, the radial head or neck may be fractured as an equivalent injury (see Images 2-3 and Images 14-16). Classification is listed in the following table.

Classification of Monteggia fracture-dislocations

Type Description Equivalent(s) %
Type IAnterior dislocation of the radial head and anterior angulation of the ulna fracture Radial head or neck fracture instead of dislocation 60
Type IIPosterior dislocation of the radial head and posterior angulation of the ulna fracture Posterior elbow dislocation
Radial head or neck fracture instead of dislocation
105
Type IIILateral dislocation of the radial head with proximal ulna fracture Radial head or neck fracture instead of dislocation 20
Type IVAnterior dislocation of the radialhead and proximal shafts of both bones fractured at same level Radial head or neck fracture instead of dislocation 5

The injury pattern is similar to both bone forearm fractures. Monteggia fracture-dislocations are included here because of the importance of not missing either injury. The isolated injuries (radial head dislocation by itself or ulna [nightstick] fracture by itself) are often treated by closed treatment with good results, but the combined injury can almost never be treated by closed methods if good results are expected. Appropriate treatment requires diagnosing both (see Imaging Studies and Images 2-3).

Floating elbow injures are another special case that can include radial head injury. Floating elbow injuries include associated ipsilateral forearm and humerus fractures. They are severe high-energy injuries. The best outcome almost always requires fixation at both levels. Standard fixation methods for the individual fractures are used (see Image 7). Surgical treatment options include open reduction internal fixation with plates and screws, excision of fragments, or radial head replacement.

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Case Number: 8028820Last Updated: 08-03-2008
Anatomy: Skeletal System   Pathology: Trauma
Modality: Conventional RadiographAccess Level: Readable by all users

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