Midshaft ulna and radius fractures in adults

INTRODUCTION — The hand is a vital structure for a multitude of motor tasks, and the forearm contributes a great deal to the hand's versatility. The forearm allows the hand to interact with objects remote from the body and enables it to pronate and supinate, capabilities that are essential for many activities of daily living as well as technical skills such as those required for music and sports. The forearm also plays an important role in protecting the head and torso from trauma, which explains in part why fractures of the forearm are among the most common.

Given the many important roles of the forearm, it is no surprise that forearm fractures can result in considerable disability, especially if treated improperly. The epidemiology, clinical anatomy, assessment, diagnosis, and nonoperative management of midshaft fractures of the radius and ulna in adults, including those associated with forearm instability (Galeazzi, Monteggia, and Essex-Lopresti injuries), are reviewed here. Distal and proximal forearm fractures in adults and pediatric forearm fractures at all locations are discussed separately:

●Adult forearm fractures (see "Distal radius fractures in adults" and "Radial head and neck fractures in adults" and "Elbow fractures and dislocation in adults")

●Pediatric forearm fractures (see "Proximal fractures of the forearm in children" and "Midshaft forearm fractures in children" and "Distal forearm fractures in children: Diagnosis and assessment")

EPIDEMIOLOGY AND RISK FACTORS — Although forearm fractures are relatively common, studies of the epidemiology of diaphyseal fractures of the forearm are scant. The incidence of diaphyseal fracture of the radius, ulna, or both is reported to be approximately 1 to 10 per 10,000 persons per year, although rates vary by age and sex. Studies show a bimodal distribution with the highest incidence among young males aged 10 to 20 years (10:10,000) and females over age 60 (5:10,000) [1-3]. Diaphyseal forearm fractures occur far less frequently than distal forearm fractures overall [1,2] but are relatively common among snowboarders (0.04 per 1000 person-days) and skiers (0.003 per 1000 person-days) [4].

Risk factors for diaphyseal forearm fractures include sports participation, postmenopausal status, osteoporosis, and frequent walking on icy surfaces [1,2]. Football and wrestling are the highest-risk sports with 0.48 and 0.21 midshaft forearm fractures per 10,000 high school athletic exposures, respectively, in one study [5]. A large (n = 695,000), 20-year cohort study from Sweden reported an increased risk of forearm fracture (hazard ratio [HR] 1.11, 95% CI 1.06-1.15) among highly active individuals compared with the average population [6]. While postmenopausal status increases the risk for both distal and midshaft forearm fractures, it increases the risk for distal fractures far more (nearly an order of magnitude in some studies) [1,2,7].

Galeazzi fractures (radial midshaft fractures with distal radioulnar joint [DRUJ] instability) account for 7 percent of all forearm fractures. Of all fractures involving only the radial shaft, one in four is a true Galeazzi injury. The less common but often missed Monteggia fracture-dislocation (fracture of the proximal third of the ulnar shaft with dislocation of the radial head) comprises 1 to 2 percent of all forearm fractures and is more common in children [7,8]. Essex-Lopresti injuries (radial head fracture with disruption of the interosseous membrane and DRUJ) account for approximately 1 percent of all radial head fractures [9]. (See 'Galeazzi fracture-dislocations' below and "Proximal fractures of the forearm in children", section on 'Monteggia fractures' and "Elbow fractures and dislocation in adults", section on 'Monteggia fracture in adults' and 'Essex-Lopresti injury' below.)

Although statistics vary widely, midshaft forearm fractures commonly occur in association with one or more concomitant injuries, particularly if high-energy trauma is involved. The wide range of statistics concerning associated injuries is likely due to the patient populations studied and other institution-specific factors as well as variation in the definition of associated injury. Studies report 33 to 82 percent of midshaft radius and ulna fracture cases are isolated injuries, while up to 50 percent involve multisystem trauma [10,11]. (See "Initial management of trauma in adults".)

Concomitant fractures of the lower extremity (eg, tibial plateau, fibula, patella, femur) or ipsi- or contralateral upper extremity (eg, humeral shaft, proximal humerus, glenoid) occur in approximately 16 to 26 percent of diaphyseal forearm fracture cases [10,11]. The most frequently associated non-musculoskeletal injuries are reported to be closed-head and peripheral nerve injuries [7]. (See "Overview of upper extremity peripheral nerve syndromes" and "Acute compartment syndrome of the extremities".)

ANATOMY — The anatomy of the forearm is complex. Only important considerations relevant to diaphyseal forearm fractures are presented here.

The radius and ulna are joined by three major groups of ligamentous structures, forming a ring:

●Triangular fibrocartilage complex including the distal radioulnar joint (DRUJ) (figure 1 and figure 2)

●Interosseous membrane

●Annular ligament (figure 3) with the adjacent proximal radioulnar joint (PRUJ) (figure 4 and figure 5)

These structures maintain bony alignment and stability while allowing pronation and supination [7,12]. Like any ring, the forearm develops instability when fracture or disruption of two or more components occurs.

The proximal ulna consists of the olecranon and coronoid, which form the trochlear notch that articulates with the humerus (figure 5). The ulnar diaphysis has minimal curvature and lies in a subcutaneous position on the posteromedial forearm. The ulnar head serves as an insertion point for the triangular fibrocartilage complex (TFCC) (figure 1 and figure 2). The radius is notable for its round head, which articulates with the humeral capitellum and rotates within the annular ligament during pronosupination (figure 5). The radial shaft has a bowed architecture that allows it to rotate around the ulnar shaft; loss of this bowed shape results in decreased range of motion with pronation and/or supination [13,14]. The distal radius broadens to a large metaphysis, creating a stable articulating surface for the scaphoid and lunate. The radius has a nutrient artery foramen on its volar surface approximately 9 cm distal to the radial head that can sometimes be mistaken for a fracture line [7].

Most muscles of the forearm can be classified into two groups: flexors of the wrist and fingers (figure 6 and figure 7 and figure 8 and figure 9) and extensors of the wrist and fingers (figure 10 and figure 11 and figure 12). The flexors lie on the anterior forearm, while the extensors lie on the posterior forearm. All anterior forearm muscles are innervated by the median nerve or its branch, the anterior interosseous nerve (figure 13), with the exception of flexor carpi ulnaris and the medial half of flexor digitorum profundus, both of which receive innervation via the ulnar nerve (figure 14 and figure 15). All posterior forearm muscles are innervated by the radial nerve or its branch, the posterior interosseous nerve (figure 16 and figure 17). Several additional forearm muscles include an elbow flexor (brachioradialis), an elbow extensor (anconeus), pronators (pronator teres, pronator quadratus), the supinator, and a thumb abductor (abductor pollicis longus).

The blood supply to the forearm arises mainly from the brachial artery, which crosses from the medial upper arm into the antecubital fossa, where it divides into multiple branches (figure 18). The ulnar and radial arteries are the principal branches, and both travel through the anterior forearm. The anterior and posterior interosseous arteries arise from the brachial artery via the common interosseous artery in the antecubital fossa. They travel adjacent to their corresponding nerve along the anterior and posterior aspects of the interosseous membrane. Displaced fractures of the radial or ulnar diaphysis can injure these deep neurovascular structures [7].

MECHANISM OF INJURY — The bimodal distribution of midshaft forearm fractures reflects the two primary mechanisms of injury [1,7]. High-energy trauma (eg, motor vehicle collisions, sports injuries, falls from a height) accounts for the large number of forearm fractures among young males with normal bone density. Low-energy trauma, primarily falls from standing, accounts for the large number of fractures among postmenopausal females, attributable to their decreased bone mineral density.

Specific fracture patterns often result from particular mechanisms:

●Radial and ulnar shaft fractures – Both-bone forearm fractures require high energy, most often involving a motor vehicle collision. The injury may be sustained from a direct blow or an indirect injury involving a bending or rotational force placed on the forearm.

●Ulnar shaft fracture – "Nightstick fractures" (isolated fracture of the ulnar shaft (image 1)) almost always result from a direct blow to the forearm, often while the victim was using the forearm to protect their head or torso from a blow.

●Galeazzi fracture-dislocation – A fall onto an extended wrist with a hyperpronated forearm is the usual cause of a Galeazzi fracture-dislocation (solitary fracture near the junction of the middle and distal thirds of the radius associated with subluxation or dislocation of the distal radioulnar joint [DRUJ] (image 2)).

●Monteggia fracture-dislocation – A fall onto an upper extremity with an extended elbow and a hyperpronated forearm is the most common cause of a Monteggia fracture-dislocation (proximal ulnar shaft fracture with radial head dislocation (image 3), usually anterior) [7,15].

●Essex-Lopresti injuries – A high-energy axial load of the forearm is the usual cause of an Essex-Lopresti injury [9,16]. The most common mechanisms are motor vehicle collisions and falls from a height onto an outstretched hand.

CLINICAL PRESENTATION AND EXAMINATION

History and presentation — The patient with a midshaft forearm fracture typically complains of pain, and possibly deformity, at the site immediately following trauma [7]. The mechanism involves either low energy (eg, ground-level fall, especially in older adults) or relatively high energy (eg, motor vehicle accident, collision during a sporting event, fall from a height). It is often difficult for the patient to recall details about the mechanism. Therefore, it is important to assess possible associated injuries at the wrist, elbow, and elsewhere, depending on the circumstances.

In some cases, history provided by the patient or perhaps a witness may reveal important details that assist the clinician. As an example, a fall onto an extended wrist and pronated forearm makes a Galeazzi-type fracture more likely, and the clinician must pay particular attention to ruling out instability of the distal radioulnar joint (DRUJ) in such cases. The mechanisms of injury associated with particular midshaft forearm fractures are described above. (See 'Mechanism of injury' above.)

Soft tissue trauma in the affected extremity is common but varies widely in severity depending upon the mechanism and patient. Such injuries may include skin lacerations, superficial and deep muscle contusions, and contusions or lacerations of tendons or neurovascular structures. Crush injuries and gunshot wounds are associated with extensive soft tissue injury, frequently including neurovascular disruption, and are often significantly contaminated. Any patient with suspected or apparent concomitant injuries of the head, spine, torso, or lower extremities following trauma should be thoroughly assessed. Severe injuries associated with forearm fractures are seen most often following motor vehicle collisions and may include closed-head injuries, peripheral nerve injuries, and concomitant fractures of the upper and lower extremities [7,10,11]. (See "Overview of upper extremity peripheral nerve syndromes" and "Acute compartment syndrome of the extremities" and "Initial management of trauma in adults".)

Physical examination — Physical examination begins with visual inspection, which may reveal swelling and an obvious deformity, suggesting a displaced fracture, or a wound overlying the fracture site (ie, open fracture) requiring immediate surgical evaluation. Palpation reveals focal tenderness at the fracture site and possibly deformity. Palpation should be performed gently.

Whenever a fracture or dislocation involving the forearm is suspected, the wrist and elbow joints should be evaluated looking for any concomitant fracture, dislocation, or other signs of injury, followed by examination of the shoulder and other extremities. Range of motion may be limited due to pain, and testing should be performed gently, judiciously, and only if there are no obvious signs of displaced fracture or dislocation. If tolerated by the patient, stability of the DRUJ may be evaluated by holding the distal radius steady while alternately applying dorsal and palmar stress to the distal ulna [9]. Motion may be compared with the uninjured forearm.

Maneuvers to elicit crepitus may cause further soft tissue damage and should be avoided. Probing open fractures should be avoided to prevent further contaminating the wound. Severe pain and a tense muscle compartment at the fracture site raise suspicion for an acute compartment syndrome, which is a surgical emergency and must be investigated promptly. (See "Acute compartment syndrome of the extremities".)

Neurovascular assessment — Serial neurovascular examinations are essential in the patient with a midshaft ulna or radius fracture given the possibility of nerve and vascular injury from direct (laceration, crush injury) or indirect (acute compartment syndrome) mechanisms. The clinician should inquire about radiating pain, paresthesias, numbness, or weakness in the affected limb. Though not common, acute nerve injury most often involves the radial or median nerves [17-19]; associated ulnar nerve injury is rare [20]. Numbness and tingling along the palmar aspect of the radial side of the hand, including the thumb, index finger, middle finger, and radial half of the ring finger, suggest injury to the median nerve (figure 13), while similar symptoms along the posterior forearm and dorsal aspect of the radial side of the hand suggest radial nerve injury (figure 16). (See "Overview of upper extremity peripheral nerve syndromes".)

More discrete motor deficits may indicate injury to the anterior or posterior interosseous nerves. These nerves are at particular risk of injury whenever the interosseous membrane is disrupted, as can occur with combined radius and ulna fractures and many Monteggia fractures.

●The anterior interosseous nerve, a deep motor branch of the median nerve (figure 13), supplies the flexor pollicis longus, lateral half of the flexor digitorum profundus, and pronator quadratus.

●The posterior interosseous nerve, a deep motor branch of the radial nerve (figure 16), supplies most wrist and finger extensors including the extensor digitorum, extensor indicis, and extensor carpi ulnaris.

COMPLEX MIDSHAFT FOREARM FRACTURES: CLASSIFICATION AND PRESENTATION

Questions for characterizing fractures — Essential questions to ask when assessing a midshaft forearm fracture include the following [7]:

●Is the fracture open or closed (any small laceration or puncture wound around fracture site raises possibility of open fracture)?

●What bones are fractured?

●Where is the fracture (proximal, middle, or distal third)?

●What is the fracture pattern (eg, simple transverse, simple oblique, wedge, comminuted (figure 19 and figure 20))?

●Is there instability at the distal radioulnar joint (DRUJ) or proximal radioulnar joint (PRUJ)?

●Is a previous implant present?

●Is a previous deformity present?

●Does bone density appear normal?

A systematic approach to describing a fracture helps convey important information to a consultant in a concise manner. More detailed assistance with fracture description is provided separately. (See "General principles of fracture management: Bone healing and fracture description", section on 'Fracture description'.)

While any forearm fracture can be described using the American Orthopedic Trauma Association (AO/OTA) classification system, in the clinical setting, this system typically is not used. The Galeazzi, Monteggia, and Essex-Lopresti fractures have their own description schemes, which are described below.

Galeazzi fractures — A Galeazzi fracture is defined as a radial midshaft fracture associated with instability of the DRUJ (image 4 and image 2). Studies of Galeazzi fracture outcomes suggest that an important demarcation for these injuries lies 7.5 cm from the distal radial articular surface. Fractures distal to this point (ie, closer to the wrist) are labeled type I and are more commonly associated with significant DRUJ instability. Fractures proximal to this point (ie, further from the wrist) are labeled type II. Galeazzi type I fractures often require more extensive surgical reconstruction of the DRUJ. Another more basic distinction for Galeazzi fractures is simple (reduction of the radius restores alignment of the DRUJ) versus complex (DRUJ cannot be realigned even with reduction of the radial shaft fracture) [7,21,22].

When a radial midshaft fracture is associated with a fracture of the distal ulnar physis or epiphysis, with or without DRUJ instability, this is termed a Galeazzi-equivalent fracture. The Galeazzi-equivalent fracture pattern occurs in children and skeletally immature adolescents due to the relative weakness of the physis compared with the triangular fibrocartilage complex (TFCC) and may be associated with subsequent ulnar growth arrest. (See "Distal forearm fractures in children: Diagnosis and assessment", section on 'Galeazzi fractures'.)

Monteggia fractures — A Monteggia fracture is defined as a fracture of the proximal third of the ulnar shaft associated with dislocation of the radial head (image 3 and image 5). As such, these are generally considered elbow injuries and are reviewed in detail separately. (See "Elbow fractures and dislocation in adults", section on 'Monteggia fracture in adults' and "Proximal fractures of the forearm in children", section on 'Monteggia fractures'.)

There are four types:

●Type I Monteggia fractures are the most common type in children and fit the classic description of an apex-anterior ulnar shaft fracture near the junction of the proximal and middle thirds, with an associated anterior radial head dislocation. Type I-equivalent injuries are seen when the same injury pattern occurs except the radial head is fractured rather than dislocated. (See "Proximal fractures of the forearm in children", section on 'Monteggia fractures'.)

●Type II Monteggia fractures are similar to type I, except both the ulnar shaft fracture apex and the radial head dislocation are directed posteriorly. Type II fractures account for approximately 80 percent of all Monteggia fractures in adults [7,23]. Occasionally, the elbow dislocates posteriorly, creating a type II-equivalent injury. (See "Elbow injuries in active children or skeletally immature adolescents: Approach", section on 'Posterior elbow dislocation' and "Elbow fractures and dislocation in adults", section on 'Elbow dislocation'.)

●Type III Monteggia fractures consist of an ulnar metaphysis fracture with lateral radial head dislocation.

●Type IV Monteggia fractures consist of fractures of the radial and ulnar shafts in association with an anterior radial head dislocation [24].

Essex-Lopresti injury — The Essex-Lopresti injury is a combination of three injuries:

●Radial head fracture

●Disruption of the interosseous membrane

●Instability of the DRUJ

The comminution, angulation, and intra-articular extension of the radial head fracture vary, and the radial head itself may or may not be dislocated from its capitellar articulation [16]. The interosseous membrane rupture includes the central band at a minimum but typically involves the entire length of the membrane. The DRUJ injury typically involves a tear of the TFCC and disruption of the ligaments of the DRUJ. Though rare, bony injury of the DRUJ, including ulnar head fracture, has been reported as an Essex-Lopresti equivalent [25].

Prompt diagnosis is the primary challenge with Essex-Lopresti injuries. Early diagnosis depends on the clinician being aware of the injury pattern and evaluating for instability of the interosseous membrane and DRUJ whenever a radial head fracture is identified. Essex-Lopresti injuries are often missed acutely [12,16]. In one small case series, only 25 percent were diagnosed at initial presentation [26].

When an Essex-Lopresti injury is suspected based on the history and physical examination, but radiographs are inconclusive, either ultrasound or magnetic resonance imaging (MRI) should be performed to evaluate the interosseous membrane and DRUJ. Ultrasound may show disruption of the central band fibers with or without surrounding hematoma. A sensitive and specific sonographic sign is dynamic herniation of muscle tissue through the interosseous space when manual pressure is applied to the muscles beneath the transducer [27]. When patients with a history of forearm fracture present with chronic forearm instability, the interosseous membrane and DRUJ should be evaluated with ultrasound or MRI depending on local resources and surgeon preference [28].

Standard classification includes three types [12]:

●Type I Essex-Lopresti injuries are acute with a radial head fracture amenable to internal fixation.

●Type II Essex-Lopresti injuries involve a comminuted radial head fracture that requires excision and prosthetic replacement.

●Type III Essex-Lopresti injuries are chronic with proximal migration of the radius and/or an irreducible radial head fracture requiring surgical treatment with radial head replacement.

Other classification schemes — A more recent scheme classifies forearm fractures based on injuries to the radius and ulna bones and their three ligamentous fixations: DRUJ, middle radioulnar joint (MRUJ; comprised of central and oblique bands of the interosseous membrane), and PRUJ [29]. This scheme provides a relatively simple and standardized method for describing forearm fractures and fracture-dislocations, which are often complex, and helps to guide operative repair. Further study of this scheme is needed before its adoption into clinical practice.

DIAGNOSTIC IMAGING

Plain radiographs — In cases of suspected midshaft forearm fracture, anteroposterior (AP) and lateral radiographs showing the entire length of the radius and ulna are usually diagnostic. Because the radius and ulna overlap on the lateral view, additional oblique views may improve assessment of the fracture.

Dedicated plain radiographs with standard views of the wrist (image 6 and image 7) and the elbow (image 8 and image 9 and image 10) are usually obtained to rule out concomitant injuries to these joints. Radiographs should be evaluated for adequacy, and the fractures themselves for displacement, shortening (especially in cases of both-bone fracture (image 11)), angulation, loss of radial bow, orientation of the fracture apex, and comminution. A high-quality lateral view of the elbow is often difficult to obtain when the patient is in pain but is important for determining the alignment of the radius and ulna relative to the humerus, and hence the integrity of the proximal radioulnar joint (PRUJ).

Several important injuries are easily missed when assessing forearm radiographs, and special attention should be paid to the following areas:

●Distal radioulnar joint – The integrity of the distal radioulnar joint (DRUJ) should be carefully examined, especially in cases of a radial shaft or radial head fracture to determine whether a Galeazzi or Essex-Lopresti fracture-dislocation, respectively, is present (image 4). Signs of a disrupted DRUJ include the following:

•Ulnar styloid fracture (image 4)

•Widening of DRUJ on posterior-anterior (PA) view

•Dorsal displacement of ulna on lateral view

•Radial shortening of ≥5 mm compared with unaffected limb (resulting in ulnar positive variance, the distance between straight lines drawn through the distal articular surfaces of the radius and ulna (image 12)).

Signs of DRUJ injury may not appear until days to weeks after the fracture, as the forearm musculature exerts deforming forces, even after the forearm has been placed in a cast [7].

●Radial head – The presence of concomitant radial head dislocation should be assessed, particularly in cases of ulnar shaft fracture (Monteggia fracture-dislocation) (image 3). This injury is easily overlooked. In one study, a Monteggia fracture was missed on initial imaging in 12 of 70 patients (26 percent) [30]. A line drawn through the radial shaft and head on any view should pass through the center of the capitellum (image 10). When radial head dislocation occurs, the radial head usually displaces in the same direction as the ulnar fracture apex (most commonly anterior). In rare cases, radial head dislocation may be delayed by days, weeks, or even years after the fracture, further complicating the diagnosis of Monteggia lesions [31].

●Rotational displacement – Proximal radial shaft fractures can develop rotational displacement due to the forces exerted by unopposed supinator and biceps muscles (image 13). Comparing the position of the bicipital tuberosity in the affected arm and the uninjured arm can help clinicians recognize rotational displacement [7,15].

Ultrasound

Accuracy and utility — For the diagnosis of distal radius fractures, bedside ultrasound is both sensitive (94 to 97 percent) and specific (86 to 99 percent) when compared with plain radiographs [32-35], and the technique necessary for an accurate examination can be learned quickly [32]. However, the accuracy of ultrasound for detecting diaphyseal forearm fractures in adults is less well studied and less clear.

Based on the limited evidence available and the authors' clinical experience, it is reasonable for experienced musculoskeletal ultrasonographers to use ultrasound as an adjunct to plain radiographs in the evaluation of suspected diaphyseal forearm fractures and associated soft tissue injuries. Ultrasound may be useful in the prehospital setting (eg, sporting venues) to screen for fracture and guide initial care [36]. However, given the risks associated with a missed midshaft forearm fracture, we believe that any patient with a suspected diaphyseal forearm fracture should be referred for plain radiographs regardless of ultrasound findings.

Technique — To perform the scan, the patient is positioned with their forearm resting on a table or upright (ie, vertical or perpendicular to the floor) with the elbow on a table and the forearm supinated to the extent tolerated by the patient. Finger traps (picture 1) can be used to suspend the forearm, if available. The sonographer scans the radial and ulnar diaphyses in both the long and short axes, moving from proximal to distal (or vice versa). At a minimum, each bone should be examined along the length of its dorsal and volar aspects. Special attention should be given to any disruption in the cortex, periosteal thickening, or hematoma around a bone.

If a fracture is identified, the degree of angulation and displacement (if any) should be estimated. Nutrient foramina are normally present in the radius and ulna and must not be mistaken for a fracture. In addition, the elbow and wrist should be evaluated for osseous alignment, intra-articular effusion, and ligamentous integrity. (See "Musculoskeletal ultrasound of the elbow" and "Musculoskeletal ultrasound of the wrist".)

Skilled musculoskeletal sonographers may use ultrasound to identify soft tissue defects suggesting disruption of the DRUJ, interosseous membrane, or proximal radioulnar joint. These findings can help to expedite appropriate referral or additional imaging.

Some of the imaging techniques needed to examine the forearm are advanced, and a detailed description is beyond the scope of this topic. Additional information is available from the ultrasound didactics program of the American Medical Society for Sports Medicine and other resources found in the following references [37,38].

Advanced imaging — Advanced imaging is generally not needed for the assessment of midshaft forearm fractures. Indications for advanced imaging include surgical planning (computed tomography [CT] or magnetic resonance imaging [MRI]), evaluation of nonunion (CT), assessment of triangular fibrocartilage complex (TFCC) tears (MRI), disruption of the interosseous membrane (MRI or ultrasound), and neurovascular injury (ultrasound, CT, or MRI with angiography) [7].

INDICATIONS FOR ORTHOPEDIC CONSULTATION OR REFERRAL — Emergency (ie, immediate) orthopedic consultation is necessary for open fractures or signs of arterial compromise or acute compartment syndrome. The accompanying table summarizes the urgent indications and timing for orthopedic consultation according to the injuries sustained and specific fracture types (table 1).

Neurologic symptoms or deficits in the absence of vascular compromise do not require emergency intervention but should be documented and, whenever possible, discussed promptly with an orthopedic consultant. In such cases, close follow-up within one to three days is warranted to monitor neurologic status, but definitive care of the fracture typically proceeds based on the fracture pattern rather than the nerve injury. It is best to obtain specialist consultation if the clinician is uncertain about the severity of injury or has limited experience with fracture assessment.

The large majority of midshaft fractures of the forearm require orthopedic consultation. The main exception is an uncomplicated "nightstick" fractures of the ulna with little to no displacement or angulation (image 1) [7,15,39]. Many midshaft forearm fractures are unstable and, even when placed in a cast, are prone to displacement from the rotational and linear forces exerted by the many muscles that insert on the forearm. These fractures require surgical fixation to avoid poor alignment and possibly nonunion. Even minor deformity of the radius or ulna can cause significant impairment of pronation or supination and disability. In addition, given the high-energy trauma involved in many forearm fractures, significant soft tissue injury is common, and this alone often warrants orthopedic consultation.

There are instances when diaphyseal forearm fractures can be treated nonoperatively by a clinician with experience treating fractures, which may not require orthopedic consultation. Such cases primarily include simple, isolated, nondisplaced fractures of the ulnar shaft ("nightstick" fractures). Nondisplaced, non-angulated, both-bone forearm fractures may be treated nonoperatively, but these are rare in adults [40]. In addition, these fractures must be followed closely with serial radiographs, and any displacement that develops despite appropriate casting warrants orthopedic referral. When there is any doubt as to the appropriateness for nonsurgical treatment, referral to an orthopedist is prudent.

INITIAL TREATMENT AND FOLLOW-UP — A range of issues pertaining to general fracture management are reviewed separately. Management specific to midshaft forearm fractures is discussed below. (See "General principles of acute fracture management" and "General principles of definitive fracture management" and "General principles of fracture management: Fracture patterns and description in children".)

Isolated ulnar shaft ("nightstick") fracture — Nonoperative treatment (casting/splinting) is the accepted approach for uncomplicated "nightstick" fractures (image 1) when all of the following criteria are met before or after successful closed reduction [7,41]:

●Greater than 50 percent apposition (ie, overlap of fracture fragments at the fracture line)

●Less than 10 degrees angulation

●No radial head dislocation

●Fracture located within middle or distal thirds of the ulna

Nonoperative treatment of fractures in the proximal third of the ulna is associated with poor outcomes (loss of pronosupination or nonunion) [7]. Pathologic, comminuted, or otherwise complicated fractures may not be good candidates for nonoperative treatment.

Initial treatment — Closed reduction may be attempted when fracture angulation exceeds 10 degrees or displacement exceeds 50 percent [41]. Our preferred method of reduction involves placing the patient's affected arm in finger traps (picture 1) while the brachium is secured with a strap or weights. This setup allows for ready manipulation of the forearm and rapid splinting once reduction is achieved.

After satisfactory alignment is achieved, the fractured arm is placed in a long-arm posterior splint with the elbow at 90 degrees and the wrist in neutral (ie, without supination or pronation) and slight extension for 7 to 10 days [7,15] or, alternatively, in a long-arm cast for three weeks [7,42]. Circumferential casts should generally not be placed until at least 72 hours after the injury to minimize the risk of compromised circulation should additional swelling develop within the cast. The cast/splint should extend from the deltoid insertion on the proximal humerus to the dorsum of the metacarpophalangeal joints.

Definitive treatment — After the initial 7- to 10-day period of immobilization, the cast or splint is removed, and radiographs are repeated to confirm fracture stability. If repeat radiographs are satisfactory, the patient is placed in a functional forearm brace for four to six more weeks [43]. The functional brace, which is generally custom-made to fit the patient, allows full flexion and extension at the elbow and wrist and full pronation and supination of the forearm (picture 2). Early motion minimizes elbow and wrist stiffness following immobilization [44].

According to a systematic review of four randomized but methodologically limited trials involving 237 patients, evidence is insufficient to recommend functional bracing over long-arm casting for the management of isolated diaphyseal ulna ("nightstick") fractures [45]. In our practice, for the majority of patients, we prefer to immobilize the extremity in a long-arm posterior splint for 7 to 10 days followed by transition to a functional brace with the assistance of an occupational therapist. Other experienced clinicians avoid elbow immobilization and proceed directly to a functional brace supported with a sling as needed for comfort. Available evidence and the general consensus among experts is that prolonged elbow immobilization (beyond 7 to 10 days) likely leads to greater harms (increased stiffness, decreased work capacity, and prolonged recovery) than benefits.

In cases where the ulnar fracture fragments are 10 to 50 percent displaced (and stability is more of a concern) and with less compliant patients, we delay functional bracing for an additional two to three weeks and are more likely to consider long-arm casting or orthopedic referral in lieu of the functional brace. In the authors' experience, off-the-shelf functional braces from several manufacturers have produced good functional outcomes and greater patient satisfaction than traditional casting.

Follow-up radiographs — Radiographic confirmation of proper alignment and healing should be obtained at one week and then every two to four weeks until healing is complete (roughly eight weeks total). In one retrospective study, 4 of 10 patients treated nonoperatively for nightstick fractures developed increasing displacement after the initial radiographs and required surgical fixation [39].

Isolated radial shaft fracture — Orthopedic evaluation for open reduction with internal fixation (ORIF) is recommended as soon as possible, but within one to two weeks is reasonable for all apparently isolated radial shaft fractures (image 13). Long clinical experience demonstrates the difficulty in ruling out distal radioulnar joint (DRUJ) instability, which may be evident only intraoperatively despite a negative computed tomography (CT) or magnetic resonance imaging (MRI) scan and may even occur days to weeks after the initial injury and despite adequate casting [22]. Poor outcomes are common when radial diaphysis fractures are treated nonoperatively [46,47].

Initial treatment — While awaiting orthopedic consultation, the patient should be placed in a well-molded double-sugar-tong splint extending over both the forearm and upper arm (picture 3) [7]. Patients are treated initially as if a Galeazzi fracture is present. (See 'Galeazzi fracture-dislocations' below.)

Galeazzi fracture-dislocations — A Galeazzi fracture is defined as a radial midshaft fracture associated with instability of the DRUJ (image 4). The severity of these injuries is not always obvious from the appearance of plain films, as DRUJ instability often is not detectable except arthroscopically, and in some cases does not manifest until days or weeks following the injury. However, case series of Galeazzi fracture patients with medical contraindications to surgery demonstrate a high rate of late-onset DRUJ instability and the severe consequences of permanent misalignment [24].

Initial treatment — Patients with confirmed or suspected Galeazzi fractures should be splinted with a well-molded double-sugar-tong splint (picture 3) and referred to an experienced orthopedist, preferably an upper extremity specialist [15,48]. In most cases, the fracture is treated surgically, including repair of the triangular fibrocartilage complex (TFCC) and DRUJ.

Combined radius and ulna (both-bone) fractures — Rarely, nondisplaced, non-angulated both-bone fractures are candidates for nonoperative treatment, especially in young children. The vast majority in adults require surgical fixation (image 11) [40]. There is no high-quality evidence that compares nonoperative and operative treatment of nondisplaced both-bone forearm fractures. We suggest consultations with an experienced upper extremity specialist to determine the best course of treatment. (See "Midshaft forearm fractures in children".)

Nonoperative treatment — Nondisplaced, non-angulated both-bone fractures may be treated initially in a well-molded bivalved long-arm cast with the wrist in a functional position, the forearm neutral, and the elbow at 90 degrees of flexion. The cast must cover from the distal palmar crease to the deltoid tuberosity to prevent forearm supination and pronation. A loop of wire or plastic should be incorporated into the radial (medial) aspect of the forearm portion of the cast just distal to the fracture site (picture 4). A strap is placed through this loop and used to suspend the cast from the patient's neck. This technique allows greater control of the ulna and may prevent late angulation.

In-cast radiographs are re-evaluated weekly for the first month to monitor for displacement and angulation. The development of any displacement or angulation requires surgical referral. A standard long-arm cast replaces the bivalved cast at two weeks and is again replaced with a new long-arm cast at four weeks to maintain a snug fit for effective immobilization (casts often become loose as soft-tissue swelling resolves and muscle atrophy develops). After one month, radiographs are obtained every two weeks and the cast replaced every four weeks until healing is complete (generally requires 12 to 16 weeks). Active range of motion of the fingers and shoulder is encouraged, and physical therapy is necessary once the cast is removed to regain function of the elbow, forearm, and wrist [15].

Operative treatment — Both-bone fractures with any angulation or displacement should be placed in a well-molded double-sugar-tong splint while awaiting surgical consultation with an orthopedist experienced in upper extremity surgery [15]. This treatment course is also indicated for patients with nondisplaced both-bone fractures who elect surgical treatment instead of the prolonged course of casting and immobilization.

Operative treatment of these complex fractures commonly requires repair of damaged soft tissue, possibly including severed tendons and neurovascular structures. The patient should be educated about the symptoms and signs associated with acute compartment syndrome and should have access to immediate care if such findings develop [7]. (See "Acute compartment syndrome of the extremities".)

Most patients are treated with ORIF. Excellent results (≥95 percent with good outcomes) have been reported with this technique [49-52]. Intramedullary nailing is a newer surgical approach but may be a good option in cases involving significant soft-tissue trauma or segmental fractures [53,54].

Monteggia fracture-dislocations — All Monteggia fractures are unstable and require surgical treatment [7,15]. Most surgeons opt for ORIF [23,55]. The patient in a primary care office or emergency department following acute injury should be placed in a well-molded double-sugar-tong splint and referred immediately to an orthopedic surgeon, preferably an upper extremity specialist. The patient should be seen by an orthopedist as early as possible, but within one to two weeks from injury is reasonable. Early range of motion is generally initiated immediately after surgery. Hardware is usually left in place; however, the subcutaneous position of the ulna may lead to irritation from the hardware, sometimes prompting removal.

Essex-Lopresti injury — Patients with confirmed or suspected acute Essex-Lopresti injury (radial head fracture with associated injury of the interosseous membrane and DRUJ) should be immobilized in a well-molded double-sugar-tong splint and referred to an experienced orthopedist, preferably an upper extremity specialist. (See 'Essex-Lopresti injury' above.)

As an intact radial head is important for forearm stability and function, in most cases, the injury is treated surgically. If the degree of comminution and displacement make internal fixation unsuitable, a prosthetic radial head may be inserted. The TFCC and DRUJ are repaired, and the interosseous membrane may be repaired as needed. The optimal method for treating a disrupted interosseous membrane in acute Essex-Lopresti injury remains controversial. For chronic injury associated with instability, reconstruction of the interosseous membrane has gained acceptance [16,28].

COMPLICATIONS — Fractures are susceptible to a range of complications, which are reviewed separately; complications of particular concern following midshaft radius and ulna fractures are discussed below. (See "General principles of fracture management: Early and late complications".)

The potential for complications with midshaft forearm fractures sustained from high-energy trauma is relatively high. With all midshaft forearm fractures, poor anatomic alignment (especially loss of radial bow) with secondary lost range of motion is a significant concern. Another important concern is chronic forearm instability due to disruption of two or more components of the forearm ring [12]. Minimizing these risks is a major reason for surgical treatment.

Additional important potential complications include the following [7,15]:

●Nerve injuries, including acute laceration or entrapment and chronic entrapment during fracture healing; radial and median nerve injuries are most common

●Wound infection (approximately 0 to 3 percent)

●Acute compartment syndrome (approximately 2 percent after open reduction with internal fixation [ORIF]) (see "Acute compartment syndrome of the extremities")

●Myositis ossificans (heterotopic ossification)

●Malunion and nonunion (approximately 2 to 10 percent)

●Radioulnar synostosis (approximately 1 to 6 percent) [7]

●Symptomatic surgical hardware requiring removal

While not common, nerve entrapment involving the radial (figure 16) or median (figure 13) nerves (or their branches) may develop days to weeks after the initial injury [56]. Suspected post-fracture nerve entrapments should be investigated with magnetic resonance imaging (MRI) or by an experienced musculoskeletal sonographer [57]. Entrapment often requires surgical exploration and release [20]. The signs and symptoms of radial and median nerve injuries are described above. (See 'Clinical presentation and examination' above.)

Rates of nonunion with diaphyseal forearm fractures range from 2 to 10 percent [47]. Fewer than 10 percent of patients require hardware removal after ORIF, usually due to persistent pain. Re-fracture rates are approximately 18 percent after such hardware removal. Therefore, many experts suggest that hardware removal be delayed 12 to 18 months, if possible, and that the extremity be splinted for an additional four to six weeks after removal [7]. Other potential complications such as infection may follow hardware removal.

Myositis ossificans (heterotopic ossification of adjacent soft tissue) may be related to the injury, the additional trauma of surgery, or both and is especially problematic when it causes synostosis of the proximal or distal radial-ulnar joint.

Joint stiffness can be a major complication, especially if treatment involved prolonged immobilization of the elbow or wrist, and may require extensive physical or occupational therapy. Uncommon-to-rare complications of midshaft forearm fractures include complex regional pain syndrome and osteomyelitis. (See "General principles of fracture management: Early and late complications", section on 'Complex regional pain syndrome' and "Nonvertebral osteomyelitis in adults: Clinical manifestations and diagnosis".)

As would be expected, fractures sustained from lower-energy trauma, such as simple "nightstick" fractures, are associated with fewer complications. Nonunion or malunion with poor anatomic alignment and lost range of motion are the primary complications seen in patients treated nonoperatively. Thromboembolic complications are rare [58].

RETURN TO SPORT OR WORK — Rehabilitation typically begins once a cast is no longer needed or immediately following surgical fixation. The major goals of rehabilitation are to help the patient regain pain-free function, full range of motion, and full strength in the injured extremity. Fine neuromotor control is generally regained with little difficulty.

Decisions concerning return to work or sport are based in part on the severity of injury and the presence of any complications. As rehabilitation can begin immediately following surgical fixation, athletes and heavy laborers often choose surgical fixation since it will speed their return to play and work. The sport and work demands of the patient must be considered in both the design of the rehabilitation program and the criteria for returning to activity. Return to work or sport requiring heavy or repetitive upper extremity loading typically requires 12 to 16 weeks of healing and rehabilitation. Return to work that places few demands on the upper extremity typically requires 8 to 12 weeks. As with any fracture, the time needed for recovery can vary widely depending on the injury, activity demands, and individual rates of healing.

As rehabilitation progresses, it is reasonable to gradually resume former activity levels, beginning with light duty at work or noncontact sports practices (mainly conditioning) [15]. Before being permitted to begin full participation at work or sport, the patient must demonstrate sufficient strength and dexterity to complete all required physical tasks. We suggest that an athlete's return to sport be supervised by an athletic trainer whenever possible.

Data on rates of return to sport in adults after diaphyseal forearm fracture are limited. A case-control study of 36 professional American football players who underwent open reduction with internal fixation (ORIF) for such injury reported a high rate of return to sport (33 of 36 returned at an average of 152.1 +/- 129.8 days), but long-term follow up showed that careers were shortened by one year and athletes played an average of two fewer games per season compared with matched controls [59].

ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:

●(See "General principles of fracture management: Bone healing and fracture description".)

●(See "General principles of fracture management: Fracture patterns and description in children".)

●(See "General principles of definitive fracture management".)

●(See "General principles of acute fracture management".)

●(See "General principles of fracture management: Early and late complications".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Fractures of the skull, face, and upper extremity in adults" and "Society guideline links: Acute pain management".)

SUMMARY AND RECOMMENDATIONS

●Epidemiology – Midshaft forearm fractures involving the radius, ulna, or both bones are relatively common and potentially debilitating. These injuries occur from low-energy trauma (eg, fall from standing), most often in postmenopausal females, or high-energy trauma (eg, motor vehicle collision), most often in young males. Forearm fractures sustained from high-energy trauma are often associated with additional, potentially life-threatening injuries, and such patients must be carefully evaluated. (See 'Epidemiology and risk factors' above and 'Anatomy' above and "Initial management of trauma in adults".)

●Mechanism of injury – Both-bone forearm fractures (image 11) require high energy, most often involving a motor vehicle collision. "Nightstick fractures" (isolated fractures of the ulnar shaft (image 1)) almost always result from a direct blow to the forearm, often while the victim was using the forearm to protect their head or torso from a blow. (See 'Mechanism of injury' above.)

Complex forearm injuries include the following (see 'Complex midshaft forearm fractures: Classification and presentation' above):

•Galeazzi fracture-dislocations (solitary fractures near the junction of the middle and distal thirds of the radius associated with subluxation or dislocation of the distal radioulnar joint [DRUJ] (image 4 and image 2)) usually result from a fall onto an extended wrist with a hyperpronated forearm.

•Monteggia fracture-dislocations (proximal ulnar shaft fractures with radial head dislocation (image 3 and image 5)) usually result from a fall onto an upper extremity with an extended elbow and a hyperpronated forearm.

•Essex-Lopresti injuries (radial head fractures with associated injury of the interosseous membrane and DRUJ) are caused by a high-energy axial load of the forearm, most often related to a motor vehicle collision or fall from a height onto an outstretched hand.

●Clinical presentation – Patients typically complain of pain, and may manifest bony deformity, at the site immediately following trauma. Associated soft tissue injury in the affected extremity is common but varies widely in severity depending upon the mechanism (more common with high-energy trauma and crush injuries) and patient. Such injuries may include skin lacerations, superficial and deep muscle contusions, and contusions or lacerations of tendons or neurovascular structures. Therefore, the injured extremity must be closely inspected and mobility of the wrist and elbow assessed as pain allows. (See 'Clinical presentation and examination' above.)

●Neurovascular assessment – Serial neurovascular examinations are essential in the patient given the possibility of nerve and vascular injury from direct (laceration, crush injury) or indirect (acute compartment syndrome) mechanisms. Inquire about radiating pain, paresthesias, numbness, or weakness in the affected limb. Though not common, acute nerve injury most often involves the radial and median nerves; ulnar nerve injury is rare. Numbness and tingling along the palmar aspect of the radial side of the hand, including the thumb, index finger, middle finger, and radial half of the ring finger, suggest median nerve injury (figure 13), while similar symptoms along the posterior forearm and volar aspect of the radial side of the hand suggest radial nerve injury (figure 16).

●Diagnostic imaging – In most cases of midshaft forearm fracture, anteroposterior (AP) and lateral radiographs showing the entire length of the radius and ulna are diagnostic. Because the radius and ulna overlap on the lateral view, additional oblique views may improve assessment. Dedicated views of the wrist and elbow are usually obtained to rule out concomitant injuries. Radiographs should be evaluated for adequacy and the fractures themselves for displacement, shortening (especially in cases of both-bone fracture (image 11)), angulation, loss of radial bow, orientation of the fracture apex, and comminution. In addition, radiographs should be reviewed carefully for the following injuries (see 'Diagnostic imaging' above):

•DRUJ injury

•Radial head dislocation

•Proximal radial shaft fracture with rotational displacement

●Orthopedic referral – Immediate orthopedic consultation is required for open fractures and for signs of arterial compromise or acute compartment syndrome. The accompanying table summarizes the urgent indications and timing for orthopedic consultation according to the injuries sustained and specific fracture types (table 1).

Neurologic symptoms or deficits on examination in the absence of vascular compromise do not require emergency intervention but warrant timely orthopedic evaluation. Many midshaft fractures of the forearm are unstable, and the large majority require orthopedic consultation. Uncomplicated "nightstick" fractures of the ulna (with little to no displacement or angulation) (image 1) that meet the following criteria may be managed nonoperatively (see 'Indications for orthopedic consultation or referral' above):

•Greater than 50 percent apposition (ie, overlap of fracture fragments)

•Less than 10 degrees angulation

•No radial head dislocation

•Fracture located within middle or distal thirds of the ulna

●Treatment – Standard initial treatment, consisting of rest, ice, elevation, immobilization, and appropriate analgesia, is provided to all patients with a midshaft forearm fracture. The method of immobilization for each type of fracture is described in the text. Definitive care is generally provided by the orthopedic surgeon to whom the patient is referred. (See 'Initial treatment and follow-up' above.)

●Complications – The potential for complications with midshaft forearm fractures sustained from high-energy trauma is relatively high. Poor anatomic alignment (especially loss of radial bow) with diminished mobility is a significant concern. Minimizing this risk is a major reason for surgical treatment. Additional important potential complications include the following (see 'Complications' above and "General principles of fracture management: Early and late complications"):

•Nerve injuries, including acute laceration or entrapment and chronic entrapment during fracture healing; radial and median nerve injuries are most common

•Wound infection

•Acute compartment syndrome (see "Acute compartment syndrome of the extremities")

•Myositis ossificans (heterotopic ossification)

•Malunion and nonunion

•Radioulnar synostosis

•Symptomatic surgical hardware requiring removal

●Return to work and sport – Return to work or sport requiring heavy or repetitive upper extremity loading typically requires 12 to 16 weeks of healing and rehabilitation. Return to work that places few demands on the upper extremity typically requires 8 to 12 weeks. As with any fracture, the time needed for recovery can vary widely depending on the injury, activity demands, and individual rates of healing. (See 'Return to sport or work' above.)