INTRODUCTION — This topic reviews issues related to fractures of the trapezium. General overviews of wrist pain and carpal fractures, as well as topics devoted to other specific carpal fractures in adults, are presented separately. (See "Evaluation of the adult with acute wrist pain" and "Evaluation of the adult with subacute or chronic wrist pain" and "Overview of carpal fractures" and "Scaphoid fractures" and "Lunate fractures and perilunate injuries" and "Capitate fractures" and "Trapezoid fractures".)

EPIDEMIOLOGY — Hand fractures are among the most common of the extremity injuries, accounting for about 18 percent of all fractures. Carpal bones fractures comprise upwards of 8 percent of hand fractures [1]. Fractures to bones of the distal carpal row—comprising the trapezium, trapezoid, capitate, and hamate— are less frequent than fractures of bones in the proximal row (scaphoid, lunate, triquetrum, and pisiform).

The trapezium is rarely injured, representing about 4 percent of all carpal fractures [1-6]. When present, trapezium fractures often occur in association with other injuries, most commonly fracture of the first (thumb) metacarpal followed by other carpal bone injuries and the distal radius [7]. (See 'Differential diagnosis' below.)

CLINICAL ANATOMY — The trapezium is on the radial side of the distal carpal row, and articulates distally with the thumb metacarpal and proximally with the scaphoid and trapezoid (image 1 and figure 1 and figure 2 and figure 3). The trapezium forms a double saddle articulation with the base of the thumb metacarpal, giving the thumb its unique multi-planar range of motion at this first carpometacarpal (CMC) joint. The trapezium has a slightly concave articulation with the scaphoid, and a flat facet articulation with the trapezoid. A longitudinal ridge is present on the volar surface, which serves as the attachment site for the transverse carpal ligament (or flexor retinaculum). The trapezium forms part of the radial aspect of the carpal tunnel, along with the scaphoid. A detailed discussion of wrist anatomy is provided separately. (See "Anatomy and basic biomechanics of the wrist" and "Finger and thumb anatomy".)

The trapezium is palpable at the base of the thumb on the dorsal side, just proximal to the base of the first metacarpal (picture 1 and picture 2). Having the patient repeatedly abduct and adduct the thumb makes palpation of the first CMC joint and the trapezium easier. The two tendons of the first dorsal extensor compartment (abductor pollicis longus and extensor pollicis brevis) pass directly over the bone. Having the patient abduct and extend the thumb puts these tendons under tension and can help distinguish them from the underlying trapezium. The trapezium is also palpable on the palmar side at the base of the thenar eminence just distal to the scaphoid tubercle.

MECHANISM OF INJURY — The two major types of trapezium injuries are body fractures and volar ridge avulsion fractures. Body fractures are most common and typically occur from axial loading or hyperextension of an adducted thumb. Body fractures are typically vertical (oriented roughly with the long axis of the hand) or comminuted. These fractures are intraarticular at the first carpometacarpal (CMC) joint or other neighboring joint and may be associated with a fracture of the first metacarpal base—a common pattern called a Bennet’s fracture (figure 4). (See "First (thumb) metacarpal fractures".)

Ridge fractures are rare and represent an avulsion of the flexor retinaculum. They result from falling onto an outstretched hand or sustaining a direct blow. They are subdivided into avulsions of the proximal base (Type 1) or of the distal tip (Type II) [8,9].

SYMPTOMS AND EXAMINATION FINDINGS — The patient with a trapezium fracture typically presents with focal tenderness over the trapezium [10]. Tenderness over the dorsal aspect of the bone is more likely with injury to the body of the trapezium. The trapezium is palpable at the base of the thumb on the dorsal side, just proximal to the base of the first metacarpal (picture 1 and picture 2). Palpating the anatomic snuffbox yields tenderness of not only the trapezium, which forms the distal portion of the snuffbox, but also the adjacent scaphoid. Thus, snuffbox tenderness may indicate injury to the trapezium. Having the patient repeatedly abduct and adduct the thumb makes palpation of the first carpometacarpal (CMC) joint and the trapezium easier.

Ecchymosis may be present. Typically there is pain and weakness with pinching (eg, when making an "OK" sign, or touching the thumb to the tip of the fifth digit). Axial loading of the thumb may elicit pain. Pain with resisted wrist flexion from a dorsiflexed start position and tenderness limited to the base of the thenar eminence may indicate a fracture of the ridge [8,11].

Examination of surrounding structures is important, as concomitant injury to other bones or to ligaments, tendons, vasculature, and nerves is relatively common. Radial artery integrity should be evaluated with palpation of the pulse at the wrist, assessment of color and capillary refill in the fingers, and the Allen test (picture 3). Median nerve assessment should include sensation testing of the thumb, index, and middle fingers, and the radial aspect of the ring fingers, and strength testing of thumb flexion, abduction and opposition.

DIAGNOSTIC IMAGING — Standard wrist radiographs (anterior posterior [AP], lateral, and oblique views) of the wrist should be obtained if fracture is suspected. Body fractures may be seen with these views (image 2 and image 3 and image 4 and image 5). However, overlapping shadows from other carpal bones can make detection difficult (image 6). The Bett view (AP with approximately 20 degrees of pronation) outlines the trapezium and the first metacarpal base without other structures superimposed (image 7). A ridge fracture is difficult to identify without using a carpal tunnel view (image 8), or computed tomography (CT) (image 9).

However, the sensitivity of conventional plain radiographs for detecting trapezium fractures is poor. One case series of 137 carpal fractures that used CT as the gold standard reported a sensitivity of 18 percent for detecting trapezium fractures with plain radiographs [5], while a similar study of 38 carpal fractures reported a sensitivity of 67 percent [4]. Thus, if radiographs are unrevealing but clinical suspicion persists, a CT or magnetic resonance imaging (MRI) study should be obtained. CT is highly accurate for identifying fracture or dislocation, and for assessing joint surfaces when there is a question of intraarticular displacement. MRI has additional value in detecting both acute and chronic bony and soft tissue injuries. If significant soft tissue injury (eg, ligament rupture or dislocation) is suspected, MRI should be obtained.

Cone beam computed tomography (CBCT) provides higher-resolution images, involves 90 percent less radiation exposure, and can be performed more quickly than conventional CT. In prospective observational case series, CBCT has demonstrated greater sensitivity than plain radiographs in detecting radiocarpal fractures. In patients with clinically suspected wrist fracture but negative plain radiographs (ie, occult fracture), CBCT detected radial or carpal fractures in 50 to 75 percent [12-15]. In two of these studies, trapezium fractures represented about 20 percent of the occult fractures, a slightly higher incidence than even scaphoid fracture [12,16]. These findings emphasize the importance of keeping a high index of suspicion for trapezium fracture in the presence of anatomic snuffbox tenderness despite negative radiographs. CBCT may be a useful tool in this setting.

DIAGNOSIS — The diagnosis of trapezium fracture may be made by plain radiograph, in conjunction with a suggestive history and examination findings. However, as the sensitivity of plain radiographs for trapezium fractures is poor, conventional computed tomography (CT), cone beam CT, or magnetic resonance imaging (MRI) may be needed when fracture is suspected but initial radiographs are normal and a definitive diagnosis is required.

DIFFERENTIAL DIAGNOSIS — Diagnoses that may coincide with or be confused with a trapezium fracture include those described below. The differential diagnosis for acute wrist pain is discussed in detail separately. (See "Evaluation of the patient with thumb pain" and "Evaluation of the adult with acute wrist pain" and "Lunate fractures and perilunate injuries".)

Fracture of scaphoid or other carpal bones — Radial sided wrist pain following trauma may be due to fracture of the scaphoid (the most commonly fractured carpal bone), trapezoid, or lunate, or any combination of these bones. Tenderness may be diffuse at the radial aspect of the wrist. Snuffbox tenderness is suggestive but not diagnostic of scaphoid fracture; note that the trapezium also lies at the distal end of the snuffbox. Diagnostic imaging to identify such fractures should include standard wrist and scaphoid views, but advanced imaging may be required. (See "Overview of carpal fractures" and "Scaphoid fractures" and "Capitate fractures".)

Distal radius fracture — Distal radius fractures are the most common fracture of the wrist and hand. They are typically caused by a fall onto an outstretched hand. Tenderness at the distal radius, and some degree of deformity and ecchymosis are common. Diagnosis is generally made by plain radiograph. Approximately 7 percent of distal radial fractures involve a concomitant carpal fracture, so a careful search for such injuries should be made [17]. (See "Distal radius fractures in adults".)

First metacarpal fractures and fracture-dislocations — Pain, dorsal swelling over the base of the first metacarpal, and difficulty with motion at the first carpometacarpal (CMC) joint suggest possible fracture of the first metacarpal. These injuries are often intraarticular, with Bennett’s fracture (includes dislocation (figure 4)) and Rolando’s fracture (comminuted but without dislocation) being common patterns. Standard views of the thumb (anterior posterior [AP], lateral, oblique)—with possible addition of a Bett view—are generally sufficient to diagnose these injuries, but CT can be useful to determine the extent of injury and position of fragments. (See "Evaluation of the patient with thumb pain" and "First (thumb) metacarpal fractures".)

First CMC dislocation — Dislocation of the first CMC joint rarely occurs in isolation. Crush injury is the most common cause. Typical findings include swelling and pain at the base of the thenar eminence, and possibly gross deformity. Joint instability may be detectable. Plain radiographs are sufficient for diagnosis. A careful search for concomitant fractures should be performed, as such injuries are common.

First CMC osteoarthritis — Degenerative arthritis at the base of the thumb (first CMC joint) is a chronic condition with insidious onset, but flares can cause acute exacerbation of pain, and may be associated with minor thumb trauma. Tenderness is localized to the first CMC joint, and small bony osteophytes may be palpable at the joint line. Pain can be reproduced with axial loading or circular motion of the first MC. Diagnosis is confirmed with plain radiographs.

de Quervain (radial styloid) tendinopathy — Overuse of the abductor pollicis longus and extensor pollicis brevis tendons within the first extensor compartment of the hand can cause de Quervain tendinopathy or tenosynovitis. Pain may acutely flare up following heavy use of the affected hand. Typically, tenderness is present over the radial styloid, and the Finkelstein test is positive (pain with thumb clenched and ulnar deviation of wrist (picture 4)). Radiographs are normal, but ultrasound may show thickening of the tendon sheath and/or tendons. (See "de Quervain tendinopathy".)

INDICATIONS FOR SURGICAL REFERRAL — Emergency referral to a specialist should be obtained for any open fracture or fracture associated with a neurologic or vascular deficit.

All body fractures displaced more than 2 mm, distal ridge fractures (Type II), and any fracture associated with injury to contiguous bones or with carpometacarpal subluxation should be referred to a hand surgeon [7-9,18]. Nearly all trapezium body fractures are intraarticular and therefore the clinician should carefully assess the joint spaces adjacent to the trapezium in all imaging studies.

Displaced fractures and all comminuted fractures should be referred. Type II (distal) trapezium ridge fractures are associated with a higher risk of symptomatic nonunion, hence the recommendation by some authors for surgical management [8,19,20].

INITIAL TREATMENT — Primary care clinicians with experience managing fractures may elect to manage the patient with an isolated, uncomplicated, non-displaced trapezium body fracture or an isolated, non-displaced trapezium ridge base (Type I) fracture.

Treatment of trapezium fractures is based on expert opinion, as studies of this fracture are scant and limited. Nonoperative treatment consists of immobilization for four to six weeks [8,9,20]. Given that swelling is usually minimal, a short arm thumb spica cast can typically be applied at initial presentation. If marked swelling is present, a thumb spica splint can be applied for three to five days (figure 5), while ice and elevation are used to reduce swelling. (See "Basic techniques for splinting of musculoskeletal injuries".)

FOLLOW-UP CARE — The patient should be assessed for cast integrity after approximately three weeks, or as needed for symptoms of poor cast fit. Biweekly cast checks may be prudent in active patients. When the cast is removed, healing should be confirmed clinically by the absence of point tenderness. Plain radiographs should be repeated after cast removal following four to six weeks of immobilization. Displacement can occur following the initial visit so careful reassessment is important. If pain persists with an avulsion or ridge fracture after appropriate treatment, refer the patient to a hand surgeon for possible excision.

Given that the trapezium has three joint faces with articular surfaces, fractures may lead to late arthrosis that may require surgical intervention. Arthritic changes may not become evident on plain radiographs for several years. Arthritic changes appear to develop more frequently after comminuted fractures, while collapse of the bone is more frequent after horizontal fractures or injuries with three or more parts [21,22].

After four to six weeks of casting, the wrist will have lost strength and mobility. Depending on the clinical circumstances, formal physical therapy or a home exercise program can be used to help the patient regain full function. The patient can stop the program once full mobility and strength are regained.

A basic home exercise program might consist of the following:

●Perform passive stretches twice daily, holding each stretch for 30 seconds. Stretch the wrist in flexion, extension, ulnar deviation, and radial deviation. The hand and wrist can be soaked in very warm water for 5 minutes prior to stretching to facilitate motion.

●Perform motion and strength exercises after stretching. Exercises should include active wrist circles 10 times in each direction, followed by two sets of 15 repetitions using appropriate resistance (eg, elastic band, dumbbell) for each of the following: wrist flexion, wrist extension, ulnar deviation, and radial deviation.

The patient's pain, motion and function should be assessed about two weeks after cast removal. Those who are having persistent, significant pain and/or functional impairment may benefit from a referral to physical therapy.

COMPLICATIONS — Nonunion of distal trapezium ridge (Type II) fractures can lead to chronic wrist tenderness and sometimes median nerve irritation, as the fracture fragment is attached to the flexor retinaculum (roof of the carpal tunnel). There are rare reports of radial artery damage in association with trapezium fractures [23]. A careful neurovascular examination should be performed acutely and at follow-up visits.

Other potential complications may include first carpometacarpal (CMC) joint stiffness and arthritis, carpal tunnel syndrome, flexor carpi radialis tendinopathy (possibly including late tendon rupture), and loss of pinch strength and function associated with pain [8,20].

RECOMMENDATIONS FOR RETURN TO SPORT OR WORK — If the patient can perform their work or sport while wearing rigid cast protection, they may proceed with their activities as tolerated during immobilization. Semi-rigid protection in a brace should be continued for four weeks after rigid immobilization is completed. Unprotected return to full sport or heavy physical labor requires full thumb and wrist range of motion and at least 80 percent strength compared with the uninjured extremity in all planes of motion at these joints.

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

●Isolated fractures of the trapezium are uncommon. The two major types of trapezium injuries are body fractures and volar ridge avulsion fractures. Axial loading of the first (thumb) metacarpal in the adducted position typically causes vertical fractures of the body through the articular surface of the trapezium. Ridge avulsion fractures are less common and occur most often from falling onto an outstretched hand. Dorsiflexion of the wrist rotates the radius and scaphoid, making the trapezium more prone to injury. Distal radius and scaphoid fractures, and proximal first metacarpal fracture dislocations, can be associated with trapezium fractures. (See 'Epidemiology' above and 'Mechanism of injury' above and 'Differential diagnosis' above.)

●The patient with a trapezium fracture typically presents with minimal swelling, but may have significant discomfort. Often, there is pain and weakness with pinching (eg, making an "OK" sign, or touching the thumb to the tip of the fifth digit). Tenderness over the dorsal aspect of the bone is more likely with injury to the body of the trapezium. Examination of surrounding structures (eg, distal radius, scaphoid, first metacarpal, median nerve) is important, as concomitant injury is common. (See 'Symptoms and examination findings' above.)

●Trapezium fractures can be difficult to visualize with standard radiographic views. A true anterior posterior (AP or Bett view) and a carpal tunnel view provide better visualization in some instances, but a computed tomography (CT) or magnetic resonance (MRI) scan may be necessary to make the diagnosis. (See 'Diagnostic imaging' above.)

●Emergency referral to a specialist should be obtained for any open fracture or fracture associated with a neurologic or vascular deficit. All body fractures displaced more than 2 mm, distal ridge fractures (Type II), comminuted fractures, and any fracture associated with injury to contiguous bones or carpometacarpal subluxation should be referred to a hand surgeon. (See 'Indications for surgical referral' above.)

●Isolated, uncomplicated, non-displaced trapezium body fractures and isolated, non-displaced trapezium ridge base (Type I) fractures can be treated effectively with four to six weeks of immobilization, typically in a short arm thumb spica cast. Regular follow-up is needed to ensure proper cast fit and to check fracture alignment. Details of management are provided in the text. (See 'Initial treatment' above and 'Follow-up care' above.)

●Involvement of one of the three articular surfaces of the trapezium in the fracture may lead to late arthrosis that requires surgical intervention. Return to sport or heavy physical labor requires full thumb and wrist range of motion and at least 80 percent strength compared with the uninjured extremity in all planes of motion at these joints. (See 'Follow-up care' above and 'Complications' above and 'Recommendations for return to sport or work' above.)