Surgical Treatment of Carpal Bone Fractures Excluding the Scaphoid

 

 

 

DEFINITION

These injuries include fractures of the lunate, triquetrum, pisiform, hamate body or hook, capitate, trapezoid, and trapezial body or ridge.

Any fracture involving the carpal bones should raise suspicion of associated carpal instability.

 

 

ANATOMY

 

Certain anatomic features of the carpal bones make them more susceptible to injury. These include the unique osteologic regions of some of the carpal bones, such as the hook of the hamate, the ridge or tubercle of the trapezium, and the neck of the capitate.

 

The slender shape and projection of the hamate hook make it an obvious injury target for direct trauma to the palmar-ulnar surface of the wrist (FIG 1A). Surgeons can identify the hook by placing their thumb interphalangeal joint on the patient's pisiform and flexing their thumb toward the patient's first web space. The surgeon's thumb tip will land directly on top of the patient's hamate hook.

 

The trapezial ridge may be considered a radial-sided analogue to the hamate hook in that it is a relatively prominent volar projection, further accentuated by the deep groove for the flexor carpi radialis (FCR) tendon that runs along its ulnar side (FIG 1B).

 

The strong, inelastic transverse carpal ligament attaches to the hamate hook ulnarly and the trapezial tubercle radially.

 

These facts make the ridge of the trapezium more susceptible to fracture after direct trauma to the thenar region of the hand.

 

 

 

FIG 1 • A. CT scan showing hamate hook. B. CT scan showing trapezial ridge.

 

 

The constricted neck portion of the capitate lies between the dense head proximally and the body distally. The body, which accounts for the distal half of the capitate, is rigidly constrained by its associations with the index, middle, and ring finger metacarpal bases; the trapezoid; and the hamate. As a result the capitate neck is a biomechanically vulnerable area.

 

Transverse plane fractures through the capitate neck are reported as being the most common.

 

Fractures across the neck place the capitate head at risk for avascular necrosis because the blood supply to the capitate flows retrograde toward the head proximally.

 

PATHOGENESIS

 

Traumatic fractures of the carpal bones may occur via direct or indirect mechanisms.

 

Direct mechanisms include crush injuries, which should alert the physician to the possible development of compartment syndrome of the hand. Compressive trauma to the hand in the anteroposterior (AP) plane will flatten the palmarly directed concave longitudinal and horizontal arches of the carpus and should raise suspicion for potential carpal body fractures and axial disruptions.

 

 

The presence of a seemingly unusual carpal bone fracture may be a herald of a globally destructive injury to the hand and other associated injuries, such as carpometacarpal (CMC) fracture-dislocations, longitudinal fractures of the metacarpals, severe thumb damage, and significant soft tissue injuries. This constellation of pathologies has been referred to as the “exploded hand” (FIG 2).

 

 

 

FIG 2 • Exploded hand is a constellation of injuries that can include CMC fracture-dislocations, longitudinal fractures of the metacarpals, severe thumb damage, and significant soft tissue damage. (Reprinted from Graham TJ. The exploded hand syndrome: logical evaluation and comprehensive treatment of the severely crushed hand. J Hand Surg Am 2006;31[6]:1012-1023; copyright 2006, with permission from Elsevier.)

 

 

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More focused direct trauma to individual carpal bones may also cause a fracture. Examples of this include direct blows to the dorsum of the hand, typically causing capitate, hamate body, triquetrum, or trapezium fractures, or direct injury to the palmar surface of the hand usually from a racquet or club, often causing a hamate hook or trapezial ridge fracture.

 

Indirect trauma includes the progressive perilunate instability patterns that are well described and may lead to fractures of the lunate, capitate, triquetrum, or other carpal bones.

 

 

Scaphocapitate syndrome involves a dorsiflexion and radial deviation mechanism by which the scaphoid bone fractures and is followed by a fracture of the capitate through the neck in the coronal plane. The capitate head may rotate up to 180 degrees from its anatomic position.

 

A progressive perilunate instability pattern can produce a similar coronal fracture through the capitate neck but normally without such a severe degree of capitate head rotation.

 

Minor indirect trauma can cause isolated carpal bone fractures.

 

 

The commonly seen avulsion fractures from the dorsum of the triquetrum may occur when a fall onto the palmar flexed wrist causes the dorsal radiotriquetral (also known as dorsal radiocarpal) ligament to avulse a portion of the dorsal cortex. However, this seemingly innocuous injury can be associated with significant radiocarpal and/or intracarpal instability patterns and the practitioner should carefully exclude these more severe injuries whenever treating a dorsal triquetral avulsion fracture.

 

An impaction type of fracture of the triquetrum body may be seen more often in patients with an elongated ulnar styloid.

 

NATURAL HISTORY

 

The natural history of carpal bone fractures depends both on the specific bone in question as well as associated impairment of other structures.

 

All of the carpal bones have at least three articular surfaces, except the pisiform, which articulates only with the triquetrum. Anatomic reduction of articular facets is a primary surgical goal in an effort to decrease the incidence and severity of posttraumatic arthritis.

 

Avascular necrosis can have a profoundly negative impact on final outcome after carpal bone fracture.

 

 

Concerns of vascular disruption arise when lunate and capitate fractures occur, although generally, fractures of the lunate are not associated with avascularity.

 

The potential for nonunion is most often seen with hamate hook fractures, capitate neck fractures, and trapezial ridge fractures, especially Palmer type II fractures that involve the tip and not the base of the ridge.

 

Barring nonunion, the related instabilities and involvement of other hand components in association with carpal fractures excluding the scaphoid are the most troublesome issues and will most significantly affect patient outcome.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Determining the mechanism of injury is the most important component of taking the patient's history.

 

Neurovascular symptoms should be explored, especially when a severe crush or high-energy mechanism is involved, or in cases of hamate hook or pisiform fractures, with special attention to the ulnar neurovascular structures within Guyon's canal.

 

 

A complete evaluation of the median, radial, ulnar, and digital nerves is warranted. Assessment of capillary refill, color, temperature, and Doppler signal determines the vascular status. Clinical or Doppler Allen examination may be warranted if radial and/or ulnar artery thrombosis or disruption is suspected.

 

The examiner should observe the patient's hand and wrist for swelling, deformity, and skin and soft tissue injuries, including possible open fractures or fracture-dislocations.

 

 

Swelling and soft tissue damage give an indication as to the severity of the injury. The presence of deformity alerts the examiner to possible carpal dislocations that require emergent reduction. Open fractures and fracture-dislocations will guide surgical management.

 

The examiner should ask the patient where the pain is most significant. The examination should start away from, and progress toward, this point. The hand, forearm, and elbow should also be palpated to assess for possible associated injuries.

 

 

The most obvious area of pain and tenderness is usually the most structurally significant. However, it may mask other more subtle injuries that should be detected by a more thorough global examination.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Routine AP, lateral, and oblique views of the wrist and hand are obtained (FIG 3A).

 

 

Radiographs of the elbow and forearm are ordered if indicated.

 

Dynamic radiographic images, including stress and distraction views, help to rule out carpal instability and may determine the ability to obtain closed reduction.

 

Special views, often best performed with fluoroscopy, help to profile difficult-to-see structures.

 

The hook of the hamate is evaluated with the carpal tunnel view or the supinated/oblique/radial deviation view with the thumb abducted (referred to as the papillon view) (FIG 3B).

 

The trapezial ridge is visualized on the carpal tunnel view (FIG 3C).

 

The pisotriquetral joint is best seen on a 45-degree supinated lateral view of the wrist.

 

Computed tomography (CT) scans effectively assess osseous detail and will often detect more subtle associated carpal fractures that may be missed on routine radiographs.

 

 

CT is considered the imaging modality of choice for confirming a hamate hook fracture if plain films are nondiagnostic.

 

NONOPERATIVE MANAGEMENT

 

Isolated carpal bone fractures without associated carpal instability, significant displacement, or intra-articular step-off may be managed nonoperatively.

 

 

This usually includes use of a cast or brace for several weeks (usually 4 to 6 weeks) until symptoms have improved, tenderness is resolving, and radiographs are stable.

 

Short-arm thumb spica casts or splints have been recommended for isolated trapezium and capitate fractures.

 

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The fingers should be left free for gentle range of motion but nothing more than light activities of daily living.

 

 

 

 

FIG 3 • A. AP radiograph of wrist showing trapezial body fracture. B. Supination, oblique, radial deviation radiograph showing normal hamate hook (arrow). C. Carpal tunnel view showing normal hamate hook (large arrow) and trapezial ridge (small arrow).

 

 

A specific fracture of note is the hamate hook.

 

 

These fractures can be treated with cast immobilization if nondisplaced and acute (<1 month).

 

There is a relatively high rate of symptomatic nonunion, and surgical intervention may eventually be necessary. Close follow-up to determine whether union has occurred is warranted because nonunions may lead to flexor tendon rupture.

 

Similar to the treatment of the hamate hook, trapezial ridge fractures may be initially immobilized and later excised if symptomatic nonunion develops.

 

SURGICAL MANAGEMENT

Indications

 

Indications for surgical management of these fractures include those that significantly involve an articular surface or are structurally destabilizing to the remainder of the carpus, such as a displaced or unstable capitate body fracture.

 

Other operative indications include those that are true for most fractures, such as open injuries and those requiring nerve, vessel, tendon, ligament, or soft tissue repair.

 

If stable and near-anatomic reduction of carpal fractures is not possible, primary limited arthrodesis or carpectomy may be indicated.

 

Because of the unique nature of each carpal bone, more specific indications will be considered for each fracture.

 

Late reconstructive options include partial or total wrist arthrodesis or proximal row carpectomy for symptomatic arthritic changes.

 

Trapezial excision with or without thumb metacarpal suspensionplasty may be used for posttraumatic arthritis after trapezial body fractures. Thumb trapeziometacarpal fusion is also an option in these situations but is usually reserved for young heavy laborers.

 

Total or hemi-wrist arthroplasty for select cases may become a more popular option as techniques improve.

Lunate Fractures

 

In general, fractures that are of sufficient size and displacement should be reduced and internally fixed.

 

Fractures that involve the palmar surface of the lunate where stout volar extrinsic wrist ligaments (long and short radiolunate) and vascular conduits (radioscapholunate ligament of Testut) attach should be stabilized.

 

If the capitate is subluxated volarly relative to the lunate and radius, such as when there is a lunate palmar lip fracture, this must be corrected with reduction and fixation of the lunate palmar fragment.

 

These fractures are routinely approached palmarly as described in Techniques.

 

Alternatively, a standard third and fourth interval dorsal exposure (described under Capitate Fractures) can be used if the fracture pattern dictates a dorsal approach and fixation.

 

Dorsal lip fractures of the lunate typically involve the scapholunate ligament, and if they are displaced, they should be reduced and stabilized to try to prevent scapholunate advanced collapse (SLAC). This is usually performed with small interfragment screw fixation.

Triquetral Fractures

 

In general, displaced fractures of the triquetral body that are of sufficient size are best treated by open reduction and internal fixation (ORIF).

 

This can be accomplished through use of pins or screws into the triquetrum alone or in combination with pinning to the lunate or to the hamate as dictated by the fracture.

 

The triquetrum may be removed in its entirety if it is not amenable to repair, although a volar intercalated segment instability (VISI) pattern may occur if performed in isolation.

 

 

An apparently isolated fracture of the triquetrum may in fact be part of a reverse perilunate instability pattern (in which the portal of energy entry is at the ulnar wrist) and may be associated with other fractures and ligament disruptions.

 

Pisiform Fractures

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The pisiform, similar to another sesamoid bone, the patella, most often fractures in a transverse pattern via an indirect avulsion mechanism through the flexor carpi ulnaris (FCU) or in a pattern of comminution from a direct blow.

 

Virtually all pisiform fractures are treated nonoperatively initially and then excised late if immobilization of the fracture fails to relieve symptoms after 2 or 3 months.

 

Fractures that are of sufficient size and displacement can be reduced and internally fixed, although this is rarely indicated.

 

The approach described in Techniques can be used for fixation or excision of the pisiform.

 

The pisiform is the last carpal bone to ossify, usually by age 12 years, and may have a nonpathologic fragmented appearance before complete ossification.

Hook of Hamate Fractures

 

If an acute hamate hook fracture is truly nondisplaced, it can be treated nonoperatively initially. If the fracture is displaced or remains persistently symptomatic or nonunited, excision is indicated, even for base fractures (FIG 4A).

 

ORIF is associated with relatively high complication rates and provides little or no advantage over simple fragment excision.

 

If ORIF is desired, the hook is exposed as described in Techniques and standard internal screw fixation principles are used.

Hamate Body Fractures

 

Fractures of the hamate body are often associated with fourth and/or fifth CMC dislocations (FIG 4B,C). ORIF is recommended to reduce the articular surfaces and stabilize the CMC joints.

 

These injuries most often result from a dorsal shear mechanism with fracture of the hamate body in the frontal plane. The metacarpals displace dorsally and proximally with the dorsal hamate fracture fragment.

 

 

 

FIG 4 • Hamate fractures. A. Supination, oblique, radial deviation radiograph showing hamate hook fracture. B,C. AP and lateral radiographs of a hamate body dorsal shear fracture associated with the small finger and ring finger CMC articulation as well as a fracture of the base of the ring finger metacarpal.

Capitate Fractures

 

Capitate fractures are by and large associated with high-energy trauma to the wrist.

 

In addition to fractures associated with progressive perilunate instability patterns and the scaphocapitate syndrome, capitate fractures may also occur due to axial loading along the middle finger ray or via direct trauma.

 

If caused by axially directed forces, the fracture line is often in the frontal plane and involves the long finger CMC joint, similar to the hamate dorsal shear fractures described earlier. The capitate may be essentially divided in half in this frontal plane.

 

In these cases, ORIF is performed through a dorsal approach.

 

Truly isolated capitate fractures with minimal displacement heal by immobilization, but this often takes time.

Trapezoid Fractures

 

The trapezoid is believed to be the least frequently fractured carpal bone.

 

As with the other bones of the distal carpal row, assessment of the associated index CMC joint is necessary to rule out a fracture-dislocation.

 

Frontal plane dorsal shear fractures of the trapezoid can destabilize the index CMC.

 

These fractures and fracture-dislocations can often be treated by closed reduction and pinning.

 

If an open approach is required to reduce the articular surface and CMC joint, a standard third and fourth extensor compartment interval dorsal approach may be used. Fixation can be accomplished with pins or screws.

 

A limited exposure (as described in the following text) is an alternative.

Trapezium Fractures

 

Fractures of the body of the trapezium nearly always involve one of its four articular facets and frequently lead to subluxation of the thumb CMC joint (FIG 5).

 

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FIG 5 • A,B. Trapezial body fractures.

 

If internal fixation is not possible, trapezial excision and palmar oblique ligament reconstruction, or the surgeon's preferred alternative procedure used for routine thumb CMC osteoarthritis, is performed.

 

 

 

Preoperative Planning

 

Examination under anesthesia, possibly with concomitant fluoroscopic imaging, helps confirm whether carpal instability coexists.

 

The surgeon should ensure that all needed fixation implants and systems are available before bringing the patient to the operating room.

 

 

A hand table, a well-padded upper arm tourniquet, and a mobile mini-fluoroscopy unit are used. Anesthesia and analgesia may be obtained through regional or general methods.

Approach

 

Carpal fractures may be approached dorsally, palmarly, radially, or ulnarly depending on the reduction needs, implants used, and location and characteristics of the fracture(s).

 

Some surgeons use wrist or small joint arthroscopy as an aid to fracture reduction and management.

TECHNIQUES

• Open Reduction and Internal Fixation of Lunate Fractures

Incision and Dissection

An extended carpal tunnel approach is used for palmar exposure.

 

 

The incision begins in the palm, just ulnar to the thenar crease and in line with the radial border of the ring finger. If the surgeon is comfortable with the deep anatomy, especially the possible anatomic variations involving the thenar motor branch, the incision in the palm may also be along the thenar crease itself.

 

The incision is extended proximally until the distal volar wrist crease is reached.

 

A curved or zigzag continuation of the incision is made at the crease to avoid crossing perpendicular to the wrist crease and associated scarring and flexion contracture.

 

The incision may be continued into the distal forearm, staying ulnar to the palmaris longus so as to avoid damage to the palmar cutaneous branch of the median nerve (TECH FIG 1A).

 

The exposure is deepened distally until the palmar fascia is encountered (TECH FIG 1B). This fascia is incised longitudinally just radial to the hamate hook. Dissection distal to the level of the hamate hook must be performed very carefully, as the ulnar neurovascular bundle is in this region.

 

The transverse carpal ligament is opened longitudinally, staying just radial to the hamate hook and again being very cautious at the distal aspect of the exposure.

 

The incision is continued proximally, releasing the distal volar forearm fascia, again staying ulnar to the palmaris longus.

 

The contents of the carpal canal are now visualized (TECH FIG 1C).

 

The digital flexors and median nerve are gently and bluntly retracted radially, revealing the floor of the canal that overlies the volar carpus (TECH FIG 1D).

 

The volar capsule of the wrist joint is incised longitudinally, providing exposure of the volar carpus and radiocarpal joint.

Reduction and Fixation

 

The palmar lip fracture of the lunate is identified, cleaned, and anatomically reduced.

 

The fracture may be fixed with small interfragment screws or buried Kirschner wires (TECH FIG 2).

 

Screws are favored, if at all possible, to minimize chances of hardware migration into the carpal tunnel.

 

Fluoroscopic images are necessary to confirm that any carpal subluxation has been corrected by stabilizing the lunate fracture.

 

The volar wrist capsule is repaired and the median nerve and digital flexors are allowed to return to their normal resting position.

 

 

The transverse carpal ligament may be repaired in a lengthened fashion or left divided (our preference). Subcutaneous tissue and skin closure is performed according to the surgeon's routine.

 

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TECH FIG 1 • Fixation of lunate palmar lip fractures. A. Carpal tunnel approach. The incision can be continued into the distal forearm, staying ulnar to the palmaris longus to avoid damage to the palmar cutaneous branch of the median nerve. B. Palmar fascia and antebrachial fascia exposed. C. Transverse carpal ligament released from hamate hook. D. Volar wrist capsule exposed.

 

 

 

TECH FIG 2 • Palmar lunate lip exposed and instrumented.

• Open Reduction and Internal Fixation of Triquetral Fractures

   

  Access to the triquetrum is usually achieved through the standard dorsal approach to the wrist that is described for capitate fractures.

   

  If there is truly isolated triquetral pathology, a more limited dorsal approach between the fifth and sixth extensor compartments is used.

   

  This incision is centered distal to that which would be used for distal radioulnar joint (DRUJ) exposure.

   

   

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  The fifth compartment (extensor digiti minimi [EDM]) is retracted radially, whereas the sixth compartment (extensor carpi ulnaris [ECU]) is retracted ulnarly.

   

  The carpal capsule is incised longitudinally or obliquely depending on the fracture and the integrity of the dorsal radiotriquetral ligament.

   

  The triquetral fracture may now be cleaned, reduced, and fixed with mini-screws or Kirschner wires as the fracture pattern prescribes.

   

  Supplemental pinning to the lunate or hamate is performed as needed.

   

  The capsule is closed, followed by routine subcutaneous tissue and skin closure all according to surgeon preference.

• Excision or Open Reduction and Internal Fixation of Pisiform Fractures

   

  A curvilinear incision is made with special care not to cross the distal volar wrist crease perpendicularly. The incision is made centered on or just radial to the pisiform.

   

   

  The ulnar neurovascular bundle is identified proximally and traced distally just past the pisiform body. The pisohamate ligament is divided.

   

  The FCU tendon, if intact, is divided longitudinally directly over the pisiform and the FCU and pisiform periosteum are elevated radially and ulnarly.

   

  At this point, the pisiform can be excised or internally fixed with minifragment screws or Kirschner wires.

   

  The risk for hardware migration, penetration into the pisotriquetral joint, and other complications in the region of the ulnar neurovascular bundle must be weighed against the good results expected with simple excision.

   

  The split FCU is closed with a nonabsorbable suture, and the subcutaneous tissue and skin are sutured in routine fashion.

• Hook of Hamate Excision

 

The hamate hook can be approached through a volar incision (our preferred method) or directly ulnar, proceeding palmar to the small finger metacarpal and dorsal to the abductor digiti minimi.

 

A volar longitudinal or curvilinear skin incision is made, centered over the hook (TECH FIG 3A).

 

The ulnar nerve and artery are identified proximally first and then traced distally, ulnar and superficial to the hamate hook (TECH FIG 3B-D).

 

Once the level of the hook is reached distally, the ulnar neurovascular bundle is gently retracted ulnarly.

 

Soft tissue attachments to the tip of the hook are incised longitudinally, including the transverse carpal ligament radially and the pisohamate ligament ulnarly and proximally.

 

The deep motor branch of the ulnar nerve should be identified as it passes distally around the base of the hamate hook in an ulnar to radial direction and must be protected during excision (TECH FIG 3E).

 

The digital flexors within the carpal canal are identified. The ring and small finger flexors, especially the profundus tendons, are

 

 

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inspected to ensure integrity and should be débrided or repaired or reconstructed as needed (TECH FIG 3F).

 

 

 

TECH FIG 3 • Excision of hamate hook fractures. A. The cardinal line of Kaplan, drawn from the apex of the first web space to the ulnar border of the hand, intersects a second line drawn along the ulnar margin of the ring digit at the hamate hook (circle). A 3-cm incision is centered over the hamate hook, gently curving with the radial border of the hypothenar eminence. B. The ulnar nerve and artery can be found proximally first and then traced distally, ulnar and superficial to the hamate hook. (continued)

 

 

 

TECH FIG 3 • (continued) C. The ulnar artery is encountered first, volar and radial to the ulnar nerve. D. With the artery retracted ulnarly, the common digital nerve to the fourth web space and the small digit ulnar sensory nerve are visualized. The deep motor branch and the hypothenar motor branch have already been given off. E. The hamate hook is subperiosteally exposed and its margins are palpated with an elevator. The deep motor branch curves radially, closely associated with the distal surface of the hook. F. Care is also taken to protect the flexor tendons during exposure and resection, seen here on the radial margin of the hook. G. Fluoroscopy after hook excision can be helpful to ensure that the hook has been removed in its entirety and that no significant prominences remain.

 

 

The tendons are then gently retracted radially.

 

The hook is cleared of all soft tissue attachments down to the level of the fracture site.

 

Use of a no. 69 Beaver blade eases this exposure.

 

Using a rongeur or similar tool, the fractured hook is removed piecemeal, again with care to protect the deep ulnar motor branch and other structures.

 

Once the fragment is removed, the remaining base is inspected and smoothed with a rongeur, curette, or similar tool until there are no sharp bony prominences (TECH FIG 3G).

 

The surrounding periosteum is closed if possible. The fingers are ranged in flexion/extension to make sure that the flexor tendons are not running over any sharp edges following the hamate hook excision. If there is a complete rupture of one of the profundus tendons due to attritional wear against the hamate hook fracture, we prefer side transfer to one of the intact profundus tendons. This typically necessitates lengthening of the exposure distally, and the neurovascular structures should be dissected and protected before performing the tendon work.

 

Subcutaneous tissue and skin closure is performed in a routine manner.

• Hamate Body Fractures

   

  A dorsal longitudinal or curvilinear incision is made centered over the ring or small finger CMC joints (TECH FIG 4A).

   

  The ring and small finger extensor tendons are retracted radially or ulnarly together or individually as needed.

   

  There can be significant variation in the anatomic appearance and interconnections of the extensor digitorum communis tendons to the ring and small fingers as well as the EDM (TECH FIG 4B). These variations usually dictate which direction to retract the tendons and whether to retract them together or individually to give the best access to the CMC joints.

   

  The CMC joint capsule and dorsal CMC ligaments are incised longitudinally. The CMC joint is cleared of any hematoma and bone fragments (TECH FIG 4C).

   

  The fracture site is cleared of hematoma and reduced while directly visualizing the distal articular surface.

   

  A dental pick is useful to reduce small fragments.

   

  The fracture is temporarily stabilized with Kirschner wires, and fluoroscopic images are taken to confirm reduction (TECH FIG 4D,E).

   

  If there is a large dorsal fragment, two or more dorsal to volar lag screws (usually 2.0-mm screws or smaller) are placed

   

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  perpendicular to the fracture line into the hamate body (TECH FIG 4F,G).

   

   

   

  TECH FIG 4 • Fixation of hamate dorsal shear fractures. A. Dorsal curvilinear incision centered on ring finger-small finger CMC joint. B. Extensor tendons exposed. C. Ring finger-small finger CMC joint exposed. D. Dorsal hamate reduced and instrumented. (continued)

   

   

   

  TECH FIG 4 • (continued) E. Temporary Kirschner wire. F,G. Screw fixation. H. Plate fixation.

   

   

  If there are several small fragments, individual screws may be used for each piece or a dorsal plate may be more effective (TECH FIG 4H).

   

  Fluoroscopic images are necessary to confirm that the screws do not protrude outside of the palmar hamate cortex which could potentially damage the ulnar neurovascular structures or flexor tendons.

   

  The dorsal capsuloligamentous sleeve is closed if possible, thus providing a smooth gliding surface between the extensor tendons and the CMC joint and hardware.

   

  The CMC joints may be pinned temporarily if still unstable.

   

  In the acute setting, if the dorsal hamate fracture is of sufficient size and securely stabilized and the joint capsule is closed, this is usually not necessary.

   

  Soft tissues and skin are closed in a routine manner.

• Capitate Fractures

   

  Often, a standard approach to the dorsal carpus is required and is carried out through the routine third and fourth extensor compartment interval.

   

  A dorsal midline longitudinal or curvilinear skin incision is made, in line with the middle finger ray and centered on the capitate.

   

  Full-thickness skin flaps are elevated radially and ulnarly.

   

  The extensor pollicis longus (EPL) is identified, released from its third extensor compartment, and transposed radially.

   

  The plane between the extensor tendons and the wrist capsule is developed by elevating the second and fourth compartments radially and ulnarly, respectively.

   

  The joint capsule and dorsal intercarpal ligament are usually divided longitudinally for access to the capitate body.

   

  Alternatively, the capsule can be opened longitudinally distal to the dorsal intercarpal ligament (TECH FIG 5).

   

  The capsule can also be incised transversely distal to the ligament and in line with its fibers, provided that exposure

   

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  of the capitate is adequate for reduction and fixation of the fracture.

   

   

   

  TECH FIG 5 • Dorsal intercarpal ligament anatomy.

   

   

  The fracture site is explored, cleaned as necessary, and stabilized with mini-screws, plates, or pins as indicated.

   

  The capsule and dorsal intercarpal ligament, if divided, are repaired.

   

  The EPL tendon is left transposed, superficial to the extensor retinaculum.

   

  The retinaculum is closed over the second and fourth compartments, followed by routine closure of subcutaneous tissue and skin.

• Trapezoid Fractures

   

  The trapezoid is approached through a limited dorsal longitudinal or curvilinear incision centered over the index CMC.

   

  Care must be exercised to identify and protect dorsoradial sensory nerve branches.

   

  The EPL tendon is identified, released, and transposed radially if needed.

   

  In the case of limited exposure of the trapezoid, simple retraction of the EPL distal to the extensor retinaculum is effective.

   

  A longitudinal interval is developed between the extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) tendons with radial and ulnar retraction, respectively.

   

  It is important to stay ulnar to the ECRL to avoid inadvertent damage to the dorsal branch of the radial artery.

   

  The capsule is divided longitudinally, exposing the trapezoid and the index CMC joint.

   

  Fracture fixation is carried out with mini-screws or pins, the capsule is closed, and routine subcutaneous tissue and skin closure is performed.

• Trapezium Fractures

 

Fractures of sufficient size and significant displacement are internally fixed (TECH FIG 6).

 

Excision rather than internal fixation may be warranted based on preoperative and intraoperative considerations.

 

Unless the fracture planes dictate a specific approach for fixation, the surgeon has the option of using whichever approach he or she is most comfortable with for routine surgical treatment of thumb CMC arthritis (see Chap. 117).

 

The Wagner approach (described in the following) is one such approach frequently used for surgical reconstruction of thumb CMC arthritis and is an effective exposure for internal fixation of body fractures.

 

 

 

TECH FIG 6 • ORIF of a trapezial body fracture.

 

 

Isolated trapezial ridge fractures and nonunions are best approached using the FCR approach centered on the scaphotrapezial joint, with retraction of the FCR ulnarly or radially out of its trapezial groove to gain access to the ridge. The Wagner approach is also effective.

 

For the Wagner approach, an incision is made along the radial border of the thumb metacarpal at the glabrous skin border.

 

At the distal volar wrist crease, the incision is continued ulnarly to the level of the FCR tendon.

 

Superficial radial sensory nerve and lateral antebrachial cutaneous nerve branches may be encountered and should be carefully preserved.

 

The thenar musculature is elevated in a radial to ulnar direction off the thumb metacarpal base.

 

Once the FCR tendon sheath is reached, it is incised longitudinally and the tendon is retracted ulnarly if necessary.

 

The capsule overlying the trapeziometacarpal and scaphotrapezial joints is opened and the joints are visualized.

The entire length of the trapezium may be exposed if needed, but we avoid excessive subperiosteal dissection, doing so only where necessary for accurate fracture reduction.

Extensive exposure may result in delayed union or nonunion.

At this point, internal fixation is performed if technically feasible, usually using lag screw fixation. The capsule is carefully reapproximated, and the subcutaneous tissues and skin are closed.

 

 

PEARLS AND PITFALLS

P.379

Carpal

instability

• Be aware of the carpal instability patterns that can accompany these fractures

  and treat accordingly.

• Failure to recognize an associated carpal instability pattern can lead to progressive carpal collapse and degeneration.

Fracture ▪ Preoperative imaging is critical so that all fractures that require stabilization are

identification identified; consider CT scanning if plain radiographs are insufficient.

• Failing to identify all unstable fractures before or during surgery can necessitate a return to the operating room.

Screw size

• Use small interfragmentary screws or even small plates for fracture fixation

whenever possible to decrease chances for hardware migration and to increase stability and possibly allow earlier range of motion.

Excision

versus fixation

• We recommend hamate hook excision as opposed to fixation due to the minimal,

if any, added benefit with fixation and the concern for significant nerve and tendon injuries with internal fixation.

Future

surgery

• Be sure the patient is aware of the possible need for further surgery in the future,

such as for hamate hook excision, addressing capitate avascular necrosis, excisional arthroplasty or arthrodesis for posttraumatic articular degeneration of any joints involved with the initial trauma, and so forth.

 

 

POSTOPERATIVE CARE

 

Patients are placed in a well-padded volar plaster wrist splint postoperatively.

 

 

The digits, including the metacarpophalangeal (MCP) joints, are left free unless there is some contraindication, such as a dorsal hamate fracture with CMC dislocation, which may require inclusion of MCP joints.

 

 

If there is no contraindication, we encourage early digital range of motion and elevation. Following ORIF of a trapezial fracture, a short-arm thumb spica splint is applied.

 

One to 2 weeks postoperatively, the patient is placed in a custom-fabricated splint (assuming there is no

associated carpal instability).

 

 

If pins were used and are left outside of the skin, pin care is initiated at this time. Pins are usually removed 4 to 8 weeks postoperatively.

 

In the case of a CMC joint fracture in which relatively large fracture fragments are anatomically stabilized with rigid internal fixation, near-immediate postoperative range of motion is initiated.

 

For most other fractures, a total of about 6 weeks of wrist immobilization is followed by progressive range of motion.

 

OUTCOMES

Most isolated carpal bone body fractures unite, and it is generally thought that these patients do quite well with regard to symptomatic and functional recovery.

The potentially symptomatic exceptions involving the hamate hook and trapezial ridge are easily treated by excision. Posttraumatic symptoms from other fractures, such as of the pisiform, trapezium, or triquetrum, may usually be addressed with isolated carpal bone excision with or without reconstruction, depending on the bone in question and other soft tissue and ligamentous considerations. For those carpal bones that cannot typically be simply excised, such as the hamate body and capitate, symptomatic posttraumatic changes may require partial or total wrist arthrodesis or other reconstructive options.

Associated injuries are often the most problematic, and patients must understand the guarded prognosis for severe destabilizing carpal injuries.

 

 

 

COMPLICATIONS

Those complications common to all surgical procedures may occur, including but not limited to bleeding, infection, damage to structures, failure of surgery, potential need for more surgery, and untoward effects of anesthesia.

Patients must also understand the relative severity of their injuries and risk for pain, stiffness, and loss of function.

Capitate neck fractures are sometimes associated with nonunion or delayed union (up to 50% or more of isolated fractures) and may be analogous to scaphoid proximal pole fractures.

Treatment of such nonunions is similar for both entities.

Although rare, avascular necrosis of the capitate head may follow a capitate neck fracture that disrupts the vascular supply.

The capitate head may be excised with or without interpositional arthroplasty if attaining union is not likely because of avascularity or other issues.

Intra-articular fractures of the carpal bones are often complicated by posttraumatic arthritis. When symptomatic, treatment with traditional arthritis remedies, such as activity modification, anti-inflammatory medications, immobilization, or steroid injection, can be tried. If these fail to relieve the patient's symptoms to his or her satisfaction, the patient may elect to proceed with partial or total wrist arthrodesis, partial carpectomy, whether of the proximal row or otherwise, or selective arthroplasties as indicated.

SUGGESTED READINGS

1. Adler JB, Shaftan GW. Fractures of the capitate. J Bone Joint Surg Am 1962;44-A:1537-1547.

    

    

2. Amadio PC, Moran SL. Fractures of the carpal bones. In: Green DP, Hotchkiss DP, Pederson RN, et al, eds. Operative Hand Surgery, ed 5. Philadelphia: Elsevier, 2005;771-768.

    

    

3. Cohen MS. Fractures of the carpal bones. Hand Clin 1997;13:587-599.

    

    

4. Gelberman RH, Gross MS. The vascularity of the wrist: identification of arterial patterns at risk. Clin Orthop Relat Res 1986;(202):40-49.

    

    

5. Hoppenfeld S, deBoer P. Surgical Exposures in Orthopaedics: The Anatomic Approach, ed 2. Philadelphia: Lippincott Williams & Wilkins, 1994.

    

    

6. Vigler M, Aviles A, Lee SK. Carpal fractures excluding the scaphoid. Hand Clin 2006;22:501-516.

    

    

7. Yu HL, Chase RA, Strauch B. Atlas of Hand Anatomy and Clinical Implications. St. Louis: Mosby, 2004.