2.1 Case history and physical examination

The patient is usually in pain and cannot rotate the forearm. As the ulnar nerve is close to the proximal ulna, its sensory and motor function should be evaluated in all cases. Occasionally, dislocations will accompany proximal forearm fractures and should be reduced and splinted as soon as possible.

2.2 Imaging

As extension is difficult and painful, an AP view is taken perpendicular to the forearm, with additional lateral and oblique elbow views ( Fig 6.3.1-2 ). However, simple x-rays are often difficult to interpret and an accurate assessment of the fracture configuration and associated injuries may only be possible at the time of surgery. Additional imaging techniques (computed tomographic [CT] scan, magnetic resonance imaging) can be helpful in complex cases or in cases of suspected ligamentous instability. Fractures may be associated with an unstable elbow joint if they involve the coronoid process or proximal ulna. The congruity of the radiohumeral and ulnohumeral joints must be carefully evaluated—a slight subluxation of these joints may indicate significant instability. The wrist must be examined and if there is any sign of injury, x-rays of the wrist must be taken too to ensure that the injury is isolated to the elbow and does not involve the distal radioulnar joint.

Simple transverse or oblique fractures of the olecranon are not necessarily stable, as they can be associated with elbow or forearm dislocations.

3.1 Proximal radius

The proximal part of the radius is a round to ellipsoid cylinder. This cylinder is circumferentially covered by cartilage, as is its cephalad surface, which articulates with the capitellum. The circumference of the radial head articulates with the radial notch of the proximal ulna, except for the posterolateral portion. Kuhn et al [1] describe the average diameter of radial head to be about 22 mm but radial heads range from 19.8 to 33.6 mm.

The radial head is offset to the radial neck and the head is angulated to the shaft. The neck shaft angle averages 140° [1].

3.2 Proximal ulna

The ulna is wrongly considered as a straight bone, around which the radius winds during forearm rotation. The anatomy of the ulna is much more complex. The ulna has cartilage coverage in three distinct parts, as it is involved in three different articulations. The two proximal articulations are the semilunar notch, a large depression formed by the olecranon and coronoid process, which articulates with the trochlear part of the distal humerus and laterally, on the coronoid process, there is a narrow, oblong, articular depression called the radial notch. It articulates with the circumferential articular surface of the head of the radius.

The proximal part of the ulna has complex anatomy which allows it to articulate with the proximal radius with anterior angulation, varus angulation, and more distally valgus angulation [2].

Keener et al [3] analyzed the anatomy of the insertion of the triceps tendon, as it was recognized that triceps-splitting approaches can result in insufficiency of the triceps mechanism. They describe a distinct lateral tendon expansion continuous with the anconeus fascia. The tendon width, thickness, and dimension of the insertion are correlated with the olecranon width.

3.3 Capsuloligamentous anatomy

The elbow is stabilized both by bony and soft-tissue constraints. The bony stabilizers are the olecranon tip and the coronoid process that engage the olecranon fossa and the coronoid fossa in maximal extension and maximal flexion respectively. Both these structures also significantly contribute to the AP stability throughout the entire range of motion. However, with intact ligaments one can resect the entire olecranon tip or up to 50% of the coronoid tip without significant influence on elbow stability.

On the medial side, the medial collateral ligament complex is the main stabilizer against valgus stress. It is composed of an anterior bundle, a posterior bundle, and a transverse bundle. The anterior bundle runs from the anterior part of the medial epicondyle of the humerus to the sublime tubercle of the ulna and the medial margin of the coronoid process. The posterior bundle runs from the inferior/posterior part of the medial epicondyle to the medial margin of the olecranon. The transverse bundle connects both the anterior and posterior bundle. The anterior bundle is the main valgus stabilizer between 20° and 120° of flexion. If intact, the elbow remains stable in valgus even in the absence of the radial head (secondary stabilizer) and the posterior bundle ( Fig 6.3.1-3a ).

The lateral collateral ligament complex is composed of three distinct ligaments: the lateral ulnar collateral ligament (LUCL), the radial collateral ligament (RCL), and the annular ligament. The LUCL and RCL are thickenings of the capsule. The LUCL extends from the lateral epicondyle, at the center of rotation of the elbow, to the supinator crest of the ulna, traversing the posterolateral aspect of the radial head. It is considered the main constraint resisting posterolateral migration of the radial head. Proximally, the LUCL and RCL are hardly distinguishable and blend with the overlying extensor tendons and intermuscular fascia. The annular ligament encircles the radial head and tapers distally as it extends over the proximal portion of the radial neck. The annular ligament originates from the anterior and posterior margins of the radial notch of the ulna and acts to stabilize the radial head to the ulna throughout the range of pronation and supination of the forearm ( Fig 6.3.1-3b ).

The elbow capsule is a relatively thin and loose structure, enclosing the humeroulnar and radiocapitellar joint. Anteriorly, it inserts 6–10 mm distal to the coronoid tip. It is most lax at a position of 80–90° flexion, the position of minimum intraarticular pressure. Therefore, patients with a joint effusion spontaneously will take this position, and posttraumatic arthrofibrosis will occur most often in this position.

4.1 AO/OTA Fracture and Dislocation Classification

The AO/OTA Fracture and Dislocation Classification of proximal forearm fractures describes both the fractures of the proximal radius and of the proximal ulna ( Fig 6.3.1-4 ).

4.2 Other key classifications

The Mason Classification of Radial Head Fractures is useful and commonly used ( Fig 6.3.1-5 ) [4]. Nijs and Devriendt [5] developed a pathomechanical classification system of the proximal ulna:

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  Type A fractures are extraarticular fractures of the proximal ulna that are the result of a bending force acting on the blocked elbow.

  
  
• 
  

  Type B fractures are partial articular fractures.

  
  
• 
  

  B1 and B2 fractures are disruptions of the extensor mechanism.

  
  
• 
  

  B3 fractures are shear fractures of the coronoid process. These can be classified according to Adams and Morrey [6]. These authors distinguish between five fracture patterns, based on CT analysis:

  
  
  
  
  • 
    

    – Type 1: tip fractures

    
    
  • 
    

    – Type 2: mid transverse

    
    
  • 
    

    – Type 3: basal

    
    
  • 
    

    – Type 4 AM: oblique anteromedial

    
    
  • 
    

    – Type 5 AL: oblique anterolateral

  
  
• 
  

  Most of these fractures are associated with radial head/neck fractures.

  
  
• 
  

  Type C fractures are complete articular fractures, resulting from impaction of the distal humerus into the proximal ulna.

6.1 Nonoperative care

Stable, nondisplaced or minimally displaced fractures of the radial head (less than 2 mm of displacement of less than 30% of the articular surface) are treated nonoperatively. A sling supports the arm for comfort but immediate full range of motion is encouraged. Some authors [7] advocate aspiration of the fracture hematoma and intraarticular infiltration with local anesthetic. This certainly gives good short-term pain relief and movement but the long-term benefit of aspiration remains debatable.

Nonoperative treatment of proximal ulnar fractures is limited to:

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  Undisplaced extraarticular fractures of the proximal ulna

  
  
• 
  

  Undisplaced partial articular fractures of the proximal ulna with the extensor mechanism intact (able to actively extend against gravity)

  
  
• 
  

  Displaced fractures of the olecranon (2U1B1) in low-demand elderly patients

Gallucci et al [8] described a series of 28 elderly patients treated by 5 days of cast immobilization followed by a sling and active mobilization as tolerated. Although 22 patients developed a nonunion, no patients required surgical treatment and function was good (140° flexion and 15° extension).

6.2 Timing of surgery

Dislocations or fracture dislocations need to be reduced urgently. Open fractures require early wound management and this is usually combined with definitive internal fixation unless there is severe contamination. Brachial artery injury with distal ischemia requires immediate treatment to restore circulation and stabilize the injury. For closed injuries, soft-tissue swelling does not often prevent early surgery in this region.

6.3 Implant selection and patient positioning

Implant selection will depend on the size of the patient and of the fracture fragments. Mini-fragment (1.5, 2.0, 2.4, or 2.7 mm) or small fragment (3.5 mm) screws and plates can be used to provide stable fixation. Tension band wire techniques may be needed and anatomical locking plates are available for the various sites on the proximal ulna and radius that commonly fracture. The extreme importance of ligamentous structures must not be forgotten. The aim should always be to produce a stable fracture fixation and stable elbow joint that allow early active motion of the elbow; this may require ligament repair using anchors and a strong suture and occasionally ligament reconstruction.

Surgery for isolated radial head fractures is performed with the patient positioned supine and the arm on a side table. The extremity is prepared from the axilla to the fingers to allow rotation of the forearm and flexion and extension of the elbow during operative fixation.

When dealing with isolated proximal ulnar fractures or complex fracture dislocations, the lateral position with the elbow flexed over a side rest is favored ( Fig 6.3.1-6 ). After skin preparation and draping a sterile tourniquet is placed on the upper arm but is only inflated in case of severe bleeding.

6.4 Operating room set-up

6.4.1 Prone position

After draping the upper arm, including the tourniquet, the hand is draped separately to allow elbow flexion during surgery and imaging. Single-use drapes or sterile sheets are used to complete patient draping. The image intensifier is draped separately ( Fig 6.3.1-7 ).

The operating room personnel and surgeon stand on the side of the injury. The assistant stands on the opposite side. Position the image intensifier on the same side as the surgeon. Place the image intensifier display screen in full view of the surgical team and the radiographer ( Fig 6.3.1-8 ).

6.4.2 Supine position

The patient is draped and the upper arm sterilized including the tourniquet allowing hand and elbow motion after draping ( Fig 6.3.1-9 ).

The operating room personnel stand on the side of injury. Position the image intensifier on the same side as the surgeon. Place the image intensifier display screen on the opposite side ( Fig 6.3.1-10 ).

Related posts:

6.1.1 Scapula 6.2.1 Humerus, proximal 6.3.3 Distal radius and wrist 6.8.2 Tibia, shaft 6.6.3 Femur, distal Section 6 Specific fractures

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