Carpal fractures of bones other than the scaphoid occur at a much lower rate than scaphoid fractures. The close relationship between the carpus, intrinsic and extrinsic wrist ligaments, and wrist kinematics makes a thorough history, clinical examination, and interpretation of imaging for carpal malalignment essential. Carpal malalignment should be addressed with reduction and fixation. Nondisplaced fractures are often treated nonoperatively and displaced intraarticular fractures are almost always treatment operatively. The physician should keep in mind the athlete’s specific goals and needs. Treatment must be individualized. Options for early return to play should be discussed when possible.
Approximately 15% to 41% carpal fractures occur in nonscaphoid carpal bones, and often occur as an avulsion, as part of a peri-lunate pattern of injury, or a direct blow/axial load.
Triquetral fractures are the most common nonscaphoid carpal fractures, accounting for 4% to 29% of all carpal fractures.
In treating athletes, the hand surgeon must determine whether further injury is risked or if early return can be accomplished safely.
Carpal fractures other than scaphoid occur at lower rates compared with scaphoid fractures. Larsen and colleagues estimated the annual incidence of nonscaphoid carpal fractures to be 36 fractures per 100,000 people in Odense, Denmark. The ratio of nonscaphoid to scaphoid fractures varies. Garcia-Elias reviewed 10,400 consecutive wrist injuries over 10 years and noted 249 carpal fractures. Out of these, 153, or 61% of carpal fractures involved the scaphoid, and 26% involved the triquetrum. Others have noted a similar ratio of scaphoid to nonscaphoid fractures with 59% to 85% being a scaphoid fracture and the remaining 15% to 41% being various other carpal injuries.
It is helpful to think of carpal fractures as belonging to 1 of 3 categories. They may be a result of an avulsion injury, usually a ligamentous avulsion. A second possibility is the occurrence of a perilunate pattern, where greater arc injuries may result in scaphoid, capitate triquetrum, and/or radial styloid fractures. Thirdly, a direct blow or an axial load can cause significant soft tissue injury along with unstable fracture patterns. In these cases, the direction of the force can be variable, resulting in a myriad of injury patterns.
The high functional demands of an athlete place them in a category where suspicion for carpal fractures should be high. Carpal fractures, especially those other than the scaphoid are frequently missed on initial presentations. Furthermore, the small size of carpal bones complicates surgery and there is the need for awareness of the vascular supply to each bone. Ligamentous injuries are often an important component of the overall injury, as well as secondary injuries to nerves or tendons.
When dealing specifically with athletes, whether recreational or professional, the goal in management is often to differentiate between injuries that need to be addressed with surgery versus those that may be managed nonoperatively. The athlete usually prefers to return to activity as soon as possible, and the treating hand surgeon needs to determine whether further injury is risked or if early return can be accomplished safely.
Triquetral fractures are the second most common carpal fracture following scaphoid fractures. They account for 4% to 29% of all carpal fractures. Three primary patterns are noted: dorsal cortical or chip fractures, triquetral body fractures, and palmar cortical fractures.
Dorsal Cortical Fractures
Dorsal cortical, or chip fractures of the triquetrum are the most common, with reports indicating they may represent up to 93% of all triquetral fractures. Proposed mechanisms of injury for these include an avulsion, impaction, or shear forces. , , An avulsion of the radiotriquetral and triquetroscaphoid ligaments could occur with extreme palmar flexion with radial deviation. , Impaction occurs with a fall onto a dorsiflexed wrist in ulnar deviation, which is a common presentation. In this scenario, the ulnar styloid is driven into the dorsal cortex of the triquetrum causing the impaction. , An increased length in the ulnar styloid has been noted in patients with triquetral fracture. Finally, a shearing force occurs from the proximal edge of the hamate during wrist dorsiflexion against the distal dorsal triquetrum.
Fractures of the body of the triquetrum are the second most common type of triquetral fractures. These are seen with high-energy injuries, and seen with greater arc perilunate type injury. In fact, a triquetral body fracture should alert the treating physician to carefully evaluate for ligamentous injury of the carpus if no other fractures are noted. Perilunate fracture-dislocations are seen in 12% to 25% of triquetral injuries. Fractures of the triquetral body may be categorized descriptively. Common patterns include sagittal fractures, fractures in the medial tuberosity, transverse fractures of the proximal pole, transverse fracture of the body, and comminuted fractures.
Palmar Cortical Fractures
Avulsion fractures on the volar aspect of the triquetrum are secondary to the palmar ulnar triquetral ligament and the lunotriquetral interosseous ligament injuries. These carry a worse prognosis than dorsal cortical fractures.
Point tenderness at the site of injury will be present in cases of triquetral fractures. Careful examination should differentiate between tenderness at the triangular fibrocartilage complex, the lunotriquetral interval, and other ulnar wrist structures. In patients with dorsal avulsion fractures, pain with wrist flexion and extension will be present.
Anteroposterior, lateral, and 45° pronated oblique radiographs of the wrist will identify most triquetral fractures, with the lateral 2 views being most helpful for dorsal cortical fractures. Palmar cortical fractures can be identified on radial deviation views. Computed tomography (CT) scans are helpful for occult triquetral fractures.
Dorsal cortical fractures are treated nonoperatively ( Fig. 1 ). These are treated with immobilization for approximately 3 to 6 weeks, either in a short arm cast or other form of immobilization. , , , As the treatment is mainly for the underlying soft tissue injury, it is tailored specifically for each athlete, and he or she must understand that the fracture is of little consequence and will likely form a fibrous nonunion. An MRI can identify extrinsic intercarpal ligament injuries or occult fractures. Initially, immobilization is achieved with a cast or splint and the patient is reexamined 1 week after the injury. If the soft tissue swelling is improved and the athlete can play his or her sport with a playing cast or splint, early return to play is allowed. However, vigilance and frequent reexamination should confirm that the soft tissue injury continues to heal. Depending on the athlete’s sport, return to play can be delayed until he or she can demonstrate safe return to play. Patients with dorsal cortical fractures have shown excellent return to motion and function. If symptoms persist for greater than 6 to 8 weeks, further imaging to evaluate for concurrent intercarpal ligament injury or triangular fibrocartilage complex injury is necessary. Symptomatic nonunions may be treated with fragment excision.
Treatment for triquetrum body fractures can be more involved ( Fig. 2 ). In the setting of perilunate fracture-dislocations, treatment often involves either arthroscopic or open reduction of the fracture or carpal injury, fracture fixation and stabilization of the intercarpal ligament injuries, such as the scapholunate or lunotriquetral joints. Nonunion of the triquetral body is rare. The wrist must be immobilized for 8 to 12 weeks after a perilunate fracture-dislocation. Return to sport depends on if use of a playing cast is allowed. Open reduction internal fixation for triquetral fractures has also been described in displaced body fractures. , It is important to look for carpal instability when treating these fractures. The threshold for an MRI must be low as the ligamentous injury will determine return to sport. In the rare situation of a triquetral malunion or nonunion, pisiform excision can provide pain relief in the setting of posttraumatic pisotriquetral arthritis. ,
Palmar cortical fractures must be evaluated with an MRI for the potential associate carpal instability, and treatment should be focused on any carpal instability. Similar to triquetral body fractures, return to sport is determined by the ligamentous injury and its treatment.
Trapezium fractures make up approximately 1% to 5% of carpal bone fractures. They commonly occur with fractures of other bones, often with the distal radius or first metacarpal. , , Isolated fractures are rare. Fractures of the trapezium involve either the body or the ridge.
Trapezium Body Fractures
Body fractures are more common, and these are described based on the fracture pattern ( Fig. 3 ). Body fractures are most commonly a sagittal split fracture, or vertical intraarticular pattern, and this frequently accompanies a Bennett fracture. A dorsoradial tuberosity fracture is the next most common trapezium body fracture. Horizontal fractures and comminuted fractures are rare. Fractures of the body of the trapezium can occur during athletics from a fall onto an outstretched hand, resulting in an axial load from the first metacarpal. This mechanism produces the sagittal split most commonly seen with a Bennett fracture. The lateral body fragment that is often attached to the first metacarpal will displace radially and proximally along with it due to the abductor pollicis longus. A fall may also impact the radial styloid into the trapezium when the thumb is abducted and hyperextended, resulting in a dorsoradial tuberosity fracture. Horizontal shear injury or a high-energy direct blow are required for horizontal fractures and comminuted fractures.
Trapezial Ridge Fractures
Palmar trapezial ridge fractures are classified either as occurring at the base of the ridge (type I) or an avulsion of the tip of the ridge (type II) ( Figs. 4 and 5 ). The ridge is a superficial structure and is palpable distal to the scaphoid tubercle. Thus, fractures are often the cause of direct trauma, which can occur when being struck by a ball or falling onto an outstretched hand. A fall onto an outstretched hand may also cause avulsion of the transverse carpal ligament.
In the acute setting, without the presence of other injuries, the trapezium is palpated distal to the volar tubercle of the scaphoid. The patient may also have pain with thumb motion, and weakness with pinch. Wrist flexion may cause pain as the flexor carpal radialis runs in a groove on the volar aspect next to the palmar ridge.
Standard radiographic views usually identify trapezium body fractures. A pronated anteroposterior (AP) view, Bett’s view, can be of further help as it shows the trapeziometacarpal articulation and help the surgeon identify any displacement. For trapezial ridge fractures, a carpal tunnel view is used. CT scans are very helpful for further detail on fractures noted in radiographs, or identifying rare fractures, such as horizontal, or coronal plane fractures.
Nondisplaced body fractures of the trapezium with joint congruity are treated with thumb spica immobilization for 4 to 6 weeks. Close follow is required as these injuries are unstable and may displace. Displaced fractures are best managed with closed versus open reduction and internal fixation (ORIF) (see Fig. 3 ). If ORIF is required, a volar Wagner incision may be used, and the thenar muscle is elevated to expose the trapezium after capsulotomy. The radial artery should be identified and protected during the approach radially and the palmar cutaneous branch of the median nerve ulnarly. Minifragment screws or Kirschner wires can be used for fixation. The goal of reduction and fixation in the case of displaced fractures is to minimize deformity and posttraumatic arthritis. Depending on the injury, bone grafts (either allograft cancellous or autologous graft) can be considered to support the articular surface.
Fractures of the volar ridge of the trapezium are classified as either base or avulsions of the tip as described earlier. Type I fractures occurring at the base may be treated nonoperatively with 4 to 6 weeks of casting. These should still be followed as the pull of the transverse carpal ligament may prevent fracture healing. Type II fractures occurring as an avulsion of the tip are treated with immobilization. If symptomatic nonunion occurs, the tip can be excised.
With all trapezium fractures, particularly in athletes trying to minimize time out of activity, one should remain vigilant of flexor carpi radialis irritation that may occur near the fracture site. This poses a theoretic risk for tendon rupture if ignored. Carpal tunnel syndrome may also develop following the fracture. In cases of missed trapezium fractures, posttraumatic arthritis can be the first sign of the injury noted, but may also be asymptomatic and noted on radiographs incidentally.
After 4 to 6 weeks of thumb immobilization with evidence of radiographic healing, the athlete begins practicing. Depending on the sport, splinting or taping may be used for comfort. Once safe return to play is demonstrated in practice, full activity is allowed 6 to 8 weeks after initiating treatment. Padded gloves may be useful as the palm can remain tender for several months. Return to activity following fragment excision procedures can occur once the incision is healed and the patient has no other findings on examination (such as carpal tunnel syndrome or flexor carpi radialis irritation). For fixation of body fractures, return to activity occurs once immobilization for 4 to 6 weeks is complete and the patient demonstrates safe return to play.
Hamate fractures make up approximately 2% of all carpal fractures. , , The unique anatomy of the hamate hook places the bone at risk, particularly if the palm is struck. The hook is the origin for the flexor digiti minimi muscles, opponens digiti minimi muscles, hypothenar muscles, pisohamate ligaments, and distal attachment of the transverse carpal ligament. It is the radial border of Guyon’s canal and the ulnar border of the carpal tunnel. Fractures of the hamate are classified as being hook of the hamate or body fractures.
Hook of the Hamate Fractures
Hook of the hamate fractures are likely underreported as they may not always be treated by a hand surgeon. These are more common in athletes compared with the general population. They occur with direction compressive forces, shear forces, or a combination of both. In a batter or golf, sports involving two-handed swings, the nondomination hand is at more at risk. In one-handed swings, such as tennis or racquet sports, the dominant hand during forehand shots receives the force of impact. Shear forces from taut flexor tendons during power grip contribute to the fracture and displacement along with direct compression.
Hamate Body Fractures
Hamate body fractures occur with high-energy axial load to the fourth and fifth digits, and can occur as a carpometacarpal fracture-dislocation. , In the athlete, these can occur with a direct fall causing an axial load at the fourth and fifth carpometacarpal joints. These joints are important for gripping and allow for about 30° of motion. Body fractures of the hamate are further divided into 4 categories: (1) proximal pole fractures, (2) fractures of the medial tuberosity, (3) sagittal oblique fractures, and (4) dorsal coronal fractures. Fractures of the medial tuberosity occur via a direct blow to the ulnar side of the wrist. The remainder are all a result of axial force transmission and high-energy trauma. ,
The most common sign of a hamate hook fracture is pain in the ulnar palm worsened with active gripping. Tenderness to palpation is felt over the hamate hook, which is 2 cm distal and radial to the pisiform. The examiner may place his or her thumb interphalangeal joint on the patient’s pisiform, direct his or her thumb toward the index metacarpophalangeal joint and roll the tip of his or her thumb directly onto the hook of the hamate. Patient’s may also complain of ulnar nerve paresthesias. Hamate hook fractures may also present late as chronic pain at the base of the hypothenar eminence. In this delayed presentation, median or ulnar nerve symptoms may accompany vague ulnar sided wrist pain. Pain may occur with resistance of ring and small finger flexion, which is worse with ulnar deviation and lessened by radial deviation of the wrist. This happens since hamate hook fracture can irritate the flexor tendons of the ring and small finger. In a chronic setting, an untreated hamate hook fracture can lead to a rupture of the ring or small finger flexor tendons.
Hamate hook fractures are difficult to recognize on standard radiographic views. Clues on the posteroanterior radiograph include the absence of the hook, which appears as a cortical ring, or sclerosis in the region due to a nondisplaced nonunion. A carpal tunnel view, a 45° supinated oblique view with the wrist dorsiflexed, and a lateral view projected through the first webspace are 3 difference specialized views to evaluate the hamate hook ( Fig. 6 ). The carpal tunnel is the most common used radiographic view, but with an acute injury this may be painful to obtain. A CT scan is a superior method over radiographs, and has been found to have 100% sensitivity and 94% specificity ( Fig. 7 ). This is in comparison with 72% sensitivity and 88% specificity for radiographs. Hamate body fractures are best identified on lateral and 45° pronated oblique radiographs, but are better defined with CT ( Fig. 8 ).