Nightstick Fracture

Etiology

As stated, the origin of the phrase "nightstick fractures" originates from injuries obtained from patients who were struck by a police truncheon in the forearm while protecting their head. More generally, these fractures are caused by any direct blow to the medial forearm, but can also be seen with excessive pronation or supination of the forearm.[3]

Epidemiology

There appears to be no increase in the incidence of nightstick fractures in men or women; however, one study did report a lower mean age of presentation in men (37 years) compared to women (52 years).[4]

History and Physical

Nightstick fractures are characteristically acute injuries caused by some form of direct trauma to the forearm. Nightstick fractures are typically closed injuries, and patients present with obvious pain and lack of function in the affected extremity.

On physical examination, practitioners should begin with a thorough examination of the skin to rule out an open fracture, which would change the immediate management of this patient. A thorough examination of the elbow and wrist is crucial to identify an associated Monteggia fracture or injury to the wrist. Clinicians should test the patient's range of motion at the elbow, palpating for any "clicks" or "clunks" at the site of the radial head. Similarly, a "shuck test" should be performed at the wrist to assess for weakness or instability at the distal radioulnar joint (DRUJ).

Evaluation

Radiography is the most important initial test to be performed in patients with suspected fractures. X-rays of the elbow with a perfect lateral are necessary to assess for appropriate alignment of the radial head to rule out a Monteggia fracture. X-rays of bilateral wrists are useful to assess the wrist joint, taking care to assess for ulnar positivity or negativity compared to the normal contralateral. Ensure that pronation and supination are equal bilaterally at the time of obtaining the radiograph, as pronation and supination affect ulnar positivity and negativity on radiographic views. Computed tomography (CT) scans are very rarely necessary, as any fracture not clearly elucidated on radiograph could be safely managed non-operatively. Thus, advanced imaging such as CT or magnetic resonance imaging (MRI) should only be used to rule out other suspected pathology.

Treatment / Management

Historically, closed non-displaced fractures with less than 50% of displacement could be treated non-operatively, given the low degree of surrounding periosteal and interosseous membrane damage associated with non-displaced fractures.[5] Multiple studies support the early mobilization as an appropriate treatment for minimally displaced fractures due to the stabilizing effects of the radius and interosseous membrane, particularly in fractures that are mid-shaft or distal shaft.[6][7][8][9] There does not appear to be a difference in outcomes with immobilization in either pronation or supination. Mid-prone positioning is appropriate and yields good results.[3][10][11](B3)

In contrast, proximal shaft fractures are more likely to require surgical intervention due to their association with radial head instability. Open isolated ulnar shaft fractures also require a formal surgical debridement with internal fixation, as is the standard of care for open fractures. More than 5 mm of displacement or shortening is an indication for surgical stabilization. Polytrauma patients are also more likely to benefit from surgical stabilization, as surgical intervention allows for easier utilization of the extremity sooner after injury.[3][12]

Differential Diagnosis

Any patient who presents with an isolated fracture of the ulnar shaft should be carefully evaluated for concomitant injuries, such as a Monteggia fracture pattern where the radial head is no longer in continuity with the capitellum. Therefore it is imperative to obtain a perfect lateral x-ray of the elbow to ensure appropriate positioning of the radial head in relation to the capitellum. Monteggia fractures do require semi-urgent operative intervention, with the restoration of the length of the ulna being critical to achieving a stable reduction of the radial head.

Practitioners should also be aware of the risk of concomitant fractures and dislocations at the wrist when evaluating ulnar shaft fractures of any degree of displacement. Contralateral films are very useful in the evaluation of ulnar variance and distal radial/ulnar stability. Intraoperatively, compare fluoroscopic views of the wrist compared to contralateral with the same amount of pronation/supination before securing fixation to ensure appropriate ulnar length. Clinicians should routinely perform a "shuck test" on the wrist joint to test the stability of the DRUJ. If unstable, K-wires can provide temporary stabilization of the DRUJ, maximizing the long-term functional outcomes of the wrist.

Prognosis

There is little meaningful data to compare operative to non-operative treatment of isolated ulnar shaft fractures due to the differences in fracture severity and configuration between operative and non-operative management.

It does seem apparent, however, that for minimally displaced fractures with limited soft tissue damage, early mobilization results in a quicker time to union than prolonged immobilization or functional bracing. Excellent or good functional outcomes appear highest for the functional brace and early mobilization groups, with below elbow bracing being slightly superior to above elbow bracing.[13]

In considering operative interventions, compression plating yields the best patient outcomes. Intramedullary nailing may be an acceptable alternative with the understanding that these patients were reported to have a poorer functional outcome in some studies.[13]

Complications

Classically, nonunion is of greatest concern in the management of isolated fractures of the ulnar shaft; however, it appears that rates of nonunion may be lower than previously thought. For non-operatively managed fractures, one meta-analysis reports a nonunion rate ranging from 2% to 4%. In nightstick fractures that were managed surgically, the nonunion rate was 0% to 2% for fractures treated with plate fixation, while fractures treated with intramedullary fixation had a 5% rate of nonunion.[13]