Triquetrum fractures

INTRODUCTION — This topic will review issues related to fractures of the triquetrum. 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 "Hamate fractures" and "Lunate fractures and perilunate injuries" and "Capitate fractures".)

EPIDEMIOLOGY — Hand fractures are among the most common of the extremity injuries, accounting for about 18 percent of all fractures. Carpal bone fractures comprise upwards of 8 percent of hand fractures [1]. Fractures to bones of the proximal carpal row—comprising the scaphoid, lunate, triquetrum and pisiform bones—are most frequent. The triquetrum is the second most common carpal fracture after the scaphoid, representing 13 to 28 percent of all carpal bone injuries [1-4].

CLINICAL ANATOMY — The triquetrum is located just distal to the ulna and the triangular fibrocartilage complex (TFCC), and proximal to the base of the hamate (image 1 and figure 1 and figure 2). The triquetrum is a small, pyramid-shaped bone that is largely covered in ligaments that connect it to surrounding structures. The triquetrum articulates with three bones: lunate, pisiform, and hamate. The lateral surface of the triquetrum is flat and articulates with the lunate, to which it is attached by the lunotriquetral ligament. The distal end faces laterally forming the sinuous, concave facet that articulates with the hamate bone. The ventromedial facet that articulates with the pisiform bone is oval shaped. The proximal end of the triquetrum forms a smooth facet for articulation with the TFCC and distal radioulnar joint. The anatomy of the wrist is discussed in greater detail separately. (See "Anatomy and basic biomechanics of the wrist".)

The triquetrum is palpable on the ulnar or dorsal aspect of the wrist just distal to the ulnar styloid and TFCC, but distinguishing it from the more distal hamate may be difficult, and the extensor carpi ulnaris (ECU) tendon may be superficial to it, further complicating palpation. Placing the wrist into radial deviation may make it more prominent and palpable.

MECHANISM OF INJURY — Triquetrum fractures typically occur from a fall onto an outstretched arm with the wrist in extension and ulnar deviation, or in extreme flexion [5]. Shearing forces exerted by the proximal hamate, distal ulna, or both may play a role. In addition, either the dorsal or volar radiotriquetral ligaments may avulse triquetral fragments at their attachments.

Triquetrum fractures may be divided into two types:

●Avulsion (cortex) fractures – An avulsion fracture, usually off the dorsal-radial surface, typically occurs with a hyperextension injury [6]. Such fractures account for up to 93 percent of triquetrum fractures [5]. Avulsion fractures of the volar cortex are rare but can occur with hyperflexion.

●Body fracture – Fractures through the body of the triquetrum are less common than avulsion fractures. This type of fracture is usually the result of a direct blow with high energy. They may occur in conjunction with a perilunate dislocation in 12 to 25 percent of triquetral injuries [7]. (See "Evaluation of the adult with acute wrist pain".)

SYMPTOMS AND EXAMINATION FINDINGS — The patient with a triquetrum fracture typically presents with a history of injury and complains of pain and swelling at the ulnar aspect of the wrist [5-9]. On examination, there is usually point tenderness dorsally or along the ulnar border of the wrist 1 to 2 cm distal to the most distal aspect of the ulna (ulnar styloid). The triquetrum is palpable on the ulnar or dorsal aspect of the wrist just distal to the ulnar styloid and TFCC. However, distinguishing it from the more distal hamate may be difficult, and the extensor carpi ulnaris (ECU) tendon may lie superficial to the bone. Placing the wrist into radial deviation may make the triquetrum more prominent and palpable (picture 1). Wrist flexion or extension may reproduce or exacerbate pain.

Examination of surrounding structures is important to evaluate for concomitant injury to other bones, ligaments, tendons and nerves. Ulnar nerve injury may cause fifth (little) and fourth (ring) finger numbness and intrinsic hand muscle weakness (weakness of finger spreading and little finger flexion and abduction). Ulnar nerve damage near the Guyon canal—in contrast to a more proximal ulnar neuropathy—will show reduced little finger flexion strength at the MCP joint but normal strength at the DIP and PIP, and reduced fourth and fifth digit sensation but normal sensation of the proximal ulnar palm.

DIAGNOSTIC IMAGING — Standard wrist radiographs (AP, lateral and oblique views) of the wrist should be obtained if fracture is suspected (image 2 and image 1 and image 3). Avulsion fractures are typically difficult to appreciate, but with careful scrutiny, a small radiodense fragment may be seen just dorsal to the proximal row of carpal bones on the lateral view. Transverse fractures of the body of the triquetrum may be visualized on an AP view (image 4A-C and image 5). However, the overall sensitivity of conventional radiography for detecting triquetrum fractures is poor (20 to 29 percent in some observational studies) [2,3]. Therefore, if a fracture is not identified using the three standard plain radiograph views but clinical suspicion persists, a computed tomography (CT) scan or magnetic resonance imaging (MRI) should be obtained.

Conventional radiography may also underappreciate displacement. CT is highly accurate for identifying fracture (image 6) or dislocation, while 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 CT (CBCT) provides images with higher resolution, involves less radiation exposure than standard CT, and is more sensitive than plain radiographs for detecting radiocarpal fractures. (See "Overview of carpal fractures", section on 'Cone beam computed tomography'.)

DIAGNOSIS — The diagnosis of triquetrum fracture may be made by positive plain radiograph, in conjunction with a suggestive history and examination findings. However, as conventional plain radiographs have poor sensitivity for these injuries, CT or 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 triquetrum fracture include those described below. The differential diagnosis for acute wrist pain is discussed in detail separately. (See "Evaluation of the adult with acute wrist pain".)

Fracture of other carpal bones — Ulnar sided wrist pain following trauma may be due to a fracture of the hamate, pisiform, lunate, capitate, or any combination of these bones. Tenderness may be diffuse at the ulnar aspect of the wrist. Diagnostic imaging to identify such fractures should include standard and carpal tunnel wrist views, and advanced imaging may be required. (See "Overview of carpal fractures".)

Fracture-dislocations of carpal bones — These potentially catastrophic injuries may be sustained from trauma, generally involving significant force, and must be diagnosed quickly to avoid possible neurovascular injury and osteoarthritis. Triquetrum body fractures are often associated with concurrent carpal instability. Examination may reveal wrist deformity; definitive diagnosis is made with radiographs or CT. Depending upon the extent of injury, immediate or urgent orthopedic consultation is required. (See "Evaluation of the adult with acute wrist pain", section on 'Perilunate and lunate dislocations' and "Lunate fractures and perilunate injuries".)

Distal radius or ulna fractures — Distal radius fractures are the most common bony injuries of the wrist. If a triquetrum fracture is seen, a careful search for concomitant radial or ulnar bony injury should be undertaken. Tenderness over the radius or ulna is typical, often accompanied by ecchymosis and deformity. Diagnosis is confirmed with radiographs, CT, or MRI. (See "Distal radius fractures in adults".)

Wrist sprain — In the absence of fracture or dislocation, sprain of any of the many wrist ligaments and capsule is likely after acute trauma. Examination typically reveals wrist tenderness and swelling, but plain radiographs are negative. Advanced imaging may be needed to definitively rule out a fracture; MRI is the best modality for imaging ligaments and joint capsule. (See "Evaluation of the adult with acute wrist pain", section on 'Wrist sprain'.)

Pisotriquetral osteoarthritis — Chronic ulnar sided wrist pain may be caused by pisotriquetral chondromalacia or osteoarthritis. A careful history reveals pain at this location that predates the acute trauma, but such trauma could cause a significant increase in pain.

Extensor carpi ulnaris tendinopathy and subluxation — The extensor carpi ulnaris (ECU) tendon can sublux or dislocate from its groove on the distal ulna, which can cause acute discomfort. Patients describe the sensation of clicking or popping as the wrist is actively moved into supination and extension, along with pain in the area of the ulnar styloid. The ECU tendon passes over the triquetrum, so ECU tenderness may be difficult to distinguish from triquetrum injury. Plain radiographs are normal, but ultrasonography typically reveals tendon pathology, as does MRI.

Triangular fibrocartilage complex (TFCC) injury — The TFCC is a complex structure located between the distal ulna and triquetrum that acts as a shock absorber for the wrist. TFCC injury typically presents after an acute injury with ulnar sided wrist pain, occasionally painful clicking in the wrist, and focal tenderness in the small "soft spot" just distal to the ulnar styloid. The TFCC compression test (axial compression of the hand with the wrist ulnar deviated) elicits pain. MRI may be needed to establish the diagnosis. (See "Evaluation of the adult with subacute or chronic wrist pain", section on 'Triangular fibrocartilage complex injury'.)

INDICATIONS FOR SURGICAL REFERRAL — Comminuted or open fractures, and fractures associated with significant nerve (ulnar) or vascular injury, should be referred immediately to a surgeon.

Triquetrum body fractures displaced 2 or more millimeters, or any fractures associated with perilunate ligament rupture or perilunate dislocation, should be referred to a hand surgeon [5,6,8,10]. Treatment of nondisplaced body fractures is controversial and based on expert opinion. As some surgeons recommend treating even nondisplaced triquetrum body fractures with open reduction and internal fixation [10], referral of any fracture of the body of the triquetrum is reasonable. Referral should be made within about 72 hours.

Avulsion fractures that are still significantly tender with radiographic signs of nonunion after six weeks of immobilization may benefit from surgical excision of the fracture fragment and should be referred [5].

TREATMENT — Primary care clinicians with experience managing fractures may elect to treat the patient with an isolated, uncomplicated triquetrum fracture (ie, no step-off, no comminution, no associated ligament injury). These primarily consist of avulsion fractures and non-displaced fractures of the body of the triquetrum.

For three to five days after injury there may be significant swelling. Thus, initial treatment includes immobilization in a volar splint with the wrist placed in slight extension, and the metacarpophalangeal (MCP) joints free to prevent joint stiffness from developing (figure 3). The splint provides compression, protection, and some pain relief, while allowing for ice to be applied and the limb to be elevated. (See "Basic techniques for splinting of musculoskeletal injuries" and "General principles of acute fracture management".)

Oral analgesics can be used for pain control. If the patient is to be referred, splint immobilization will suffice until definitive management can be determined by the consultant.

Due to the absence of controlled studies, treatment of triquetrum fractures is based on expert opinion and limited evidence from case series. Avulsion fractures without major wrist instability are definitively treated—after acute swelling has subsided—with three to six weeks in a short arm cast with the wrist placed in slight extension and the MCP joints free. Avulsion fractures are generally of little consequence, as most go on to an asymptomatic fibrous union, but they do indicate underlying soft tissue injury that must be allowed to heal. Hence, immobilization is important [5-8,10].

Nondisplaced, uncomplicated triquetrum body fractures that are to be treated conservatively should be immobilized in a short arm cast as above for four to six weeks [6]. If after this period of time the fracture is not healing clinically, the patient should be referred for further evaluation. A non-healing triquetrum fracture is identified by persistent point tenderness at the fracture site and of the absence of healing on plain radiograph (eg, no callus formation) at six seeks. (See 'Indications for surgical referral' above.)

FOLLOW-UP CARE — The patient should be assessed for cast integrity after about three weeks or as needed for symptoms of poor cast fit. Biweekly cast checks may be prudent in very 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. Small avulsion fractures may not need a follow-up plain radiograph if the injury is progressing well clinically.

Some patients may experience mild discomfort over the dorsum of the wrist for several months. (See 'Indications for surgical referral' above.)

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 — Reports of nonunion and other major complications involving uncomplicated triquetrum fracture are extremely rare [6]. The great majority of such fractures appear to heal well.

RECOMMENDATIONS FOR RETURN TO SPORT OR WORK — Activities, including sports, can be resumed with cast protection as soon as the acute pain subsides. Baseball, golf, and racquet sports, or heavy labor involving wrist flexion, are not advised during cast treatment. After casting, return to these activities is permitted once the patient has achieved full wrist range of motion and at least 80 percent strength in all wrist planes of motion, compared to the uninjured side. This may occur one to three weeks after cast removal, but additional time may be needed in some cases.

In the rare case of an avulsion nonunion, an athlete can continue to play, with the wrist protected from contusion as desired, until excision can be performed at the end of the season.

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 and clinical anatomy – The triquetrum is located just distal to the ulna and the triangular fibrocartilage complex (TFCC), and proximal to the base of the hamate (image 1 and figure 1 and figure 2), and is connected to neighboring bones by a large number of ligaments. The triquetrum is the second most common carpal fracture after the scaphoid. Unlike the scaphoid and capitate, blood supply to the triquetrum is robust and there is little chance of avascular necrosis. (See 'Clinical anatomy' above and 'Epidemiology' above.)

●Mechanism, clinical presentation, and examination – Triquetrum fractures typically occur from a fall onto an outstretched arm with the wrist in extension and ulnar deviation, or in extreme flexion. Dorsal avulsion fractures are most common. Body fractures can occur with a direct blow to the area. With either, patients typically give a history of wrist trauma and present with pain and some swelling at the ulnar aspect of the wrist. Examination reveals tenderness either dorsally or along the ulnar border of the wrist (picture 1). Concomitant injury to adjacent structures is common, and so the area must be carefully examined, including ulnar nerve function. (See 'Mechanism of injury' above and 'Symptoms and examination findings' above.)

●Diagnostic imaging – Diagnosis is established with imaging. Avulsion fractures of the triquetrum are typically seen on the lateral view (image 6) of standard plain wrist radiographs, while body fractures are generally found on an antero-posterior (AP) view. However, the sensitivity of conventional radiography for detecting triquetrum fractures is poor, and additional views or advanced imaging studies may be needed. (See 'Diagnostic imaging' above.)

●Indications for surgical referral – Fractures with any of the following characteristics should be referred to a surgeon:

•Open fracture

•Fracture associated with nerve (ulnar) or major vascular injury

•Displacement of 2 mm or greater, or comminution

•Significant associated injury, such as perilunate ligament rupture or perilunate dislocation

In addition, the treatment of body fractures of the triquetrum is controversial and referral is reasonable, even if the fracture is non-displaced. Avulsion fractures that remain significantly tender without radiographic signs of healing after six weeks of immobilization should be referred. (See 'Indications for surgical referral' above.)

●Management – Isolated, uncomplicated triquetrum fractures (ie, no step-off, no comminution, no associated ligament injury) are suitable for management by primary care clinicians with experience managing fractures. Definitive treatment of avulsion fractures consists of immobilization for three to six weeks in a short arm cast with the wrist placed in slight extension and the MCP joints free. Body fractures require a short arm cast for four to six weeks. Uncomplicated triquetrum fractures generally heal without complications. Details of treatment are provided in the text. (See 'Treatment' above and 'Follow-up care' above.)