Triquetral Fractures

A triquetral fracture is a fracture of the triquetrum, the bone on the ulnar side of the proximal carpal row. The dorsal cortical chip is by far the commonest pattern, over 90% of cases, though body fractures also occur.

How common. Conventionally the triquetrum is the second most common carpal fracture, at 14-20% of all carpal fractures, after the scaphoid at 70-80%. The Swedish Fracture Registry's 6,542 carpal fractures support that ranking, with scaphoid 60% and triquetrum 25%, a share above the 14-20% usually quoted.

The rank depends on how hard you look. A German series in which 91% of patients underwent CT found the triquetrum the commonest carpal fracture of all, ahead of the scaphoid. Only 20% of triquetral fractures are detected on radiographs, so registries built on plain films systematically under-count them while CT-based series do not. Quote "second most common" with that caveat rather than as a fixed fact.

The patients are young to middle-aged adults, with a male predominance.

The bone. Pyramidal, triangular when viewed from its ulnar aspect, and the third largest bone of the proximal row after the scaphoid and lunate. It forms the ulnar border of the proximal row and articulates on four sides:

• Lunate - on its radial side, as part of the intercalated segment
• Hamate - distally, through the hamate facet, with the proximal pole of the hamate
• Pisiform - on the volar surface, a small sesamoid articulation in the volar groove
• TFCC - proximally, through the ulnocarpal complex

The dorsal surface carries a ridge for ligament attachments, and it is the site of the commonest fracture.

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The blood supply. Multiple dorsal and volar nutrient vessels enter the bone: the dorsal surface carries the primary supply, the volar surface secondary vessels, and the other non-articular surfaces add more. No single vessel dominates, unlike the lunate, so the risk of AVN is lower than in other carpals and the healing potential is reliable.

Kinematics. The triquetrum is part of the proximal row "intercalated segment" and moves with the scaphoid and lunate as a functional unit, with limited independent motion. It transmits force from the ulnar carpus, which carries less load than the radial side; the pisiform modifies that transmission, and the hamate comes into contact with it in ulnar deviation.

The mechanism of the dorsal chip. Three explanations compete, and both papers cited on this page reject the one most commonly taught:

• Ligament avulsion (traditional teaching) - the strong radiotriquetral ligament, perhaps with a contribution from the lunotriquetral ligament, pulls off a dorsal flake in traction. It is the most repeated explanation and the weakest.
• Ulnar styloid impaction (Levy) - a cadaveric and radiographic study written specifically to test the avulsion theory disproved it, concluding that a chisel action of the ulnar styloid against the dorsum of the triquetrum causes the chip in a fall onto an outstretched hand held in strong dorsiflexion and ulnar deviation. A prolonged ulnar styloid was noted in every case.
• Hamate impaction (Höcker and Menschik) - a larger series agreed the mechanism is impingement rather than avulsion, but named a different impactor, the dorso-proximal edge of the hamate.

What to say. The dorsal chip is an impaction (chisel) injury in extension and ulnar deviation that shears off the dorsal cortex, with the impactor disputed between ulnar styloid and hamate. Every proposed mechanism produces a similar dorsal flake, so the distinction matters less for treatment than for predicting stability: an impaction mechanism predicts a dorsal cortical flake that does not destabilise the carpus, which is what the outcome data show.

The anatomical classification is the practical one. It is based on fracture location, and location guides both treatment and prognosis.

Type I, the dorsal chip. A small cortical avulsion from the dorsal surface, usually under 5mm.

Type II, the body fracture. A fracture through the substance of the triquetrum, which may point to a higher-energy injury. Unlike chips, body fractures may indicate a greater-arc perilunate injury, so always assess for carpal malalignment and associated injuries when one is present.

Type III, the volar avulsion. Rare as an isolated injury. It is of ligamentous origin (pisotriquetral, ulnotriquetral), usually associated with perilunate dislocation as part of the greater-arc pattern, and it requires assessment for carpal instability.

Type IV, the comminuted body. A high-energy injury with significant fragment displacement and a poor soft-tissue envelope.

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MechanismStability

Mechanism predicts the severity of the injury and the associated injuries to look for, and so guides the workup.

• Impaction - extension and ulnar deviation drive the hamate or ulnar styloid into the triquetrum; typically an isolated dorsal chip, low energy, no carpal instability
• Avulsion - ligament traction, which may involve the radiotriquetral or lunotriquetral ligaments; moderate energy, so assess for subtle instability
• Perilunate-associated - a body or volar fracture as part of a greater-arc ligamentous disruption; high energy, and requires comprehensive evaluation
• Direct trauma - a direct blow to the ulnar wrist; a rare, isolated body fracture, which may be comminuted, with variable associated injuries

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Stability assessment is critical for treatment planning.

• Stable - isolated dorsal chip, undisplaced body fracture, no carpal malalignment, intact ligaments. Conservative.
• Potentially unstable - large body fragment, minor displacement, subtle widening at the LT interval. Conservative, with close and careful follow-up.
• Unstable - displaced body fracture, associated carpal instability, a perilunate injury pattern, VISI or DISI on the lateral. Surgical stabilisation.

History. The usual mechanism is a fall onto the outstretched hand with ulnar deviation. Less often:

• Direct blow - rare, usually to the dorsum of the wrist
• Sports injury - contact and ball sports
• Motor vehicle accident - dashboard injury

Establish the exact mechanism and wrist position, the energy (height of fall, impact speed), the immediate symptoms and pattern of swelling, any previous wrist injury or symptoms, and hand dominance and occupational demands.

Examination. Swelling over the ulnar wrist may be subtle with a dorsal chip, so compare with the other side, and check the skin. The finding that matters is point tenderness over the triquetrum on the dorsal ulnar wrist. The anatomical snuffbox is negative, which rules out the scaphoid; examine the DRUJ for associated injury, and note that the pisiform may be tender as well.

Motion is limited by pain in the acute setting, ulnar deviation particularly. Assess forearm rotation for DRUJ involvement. Neurovascular function is usually preserved, but check the ulnar nerve and document a baseline for comparison.

Special tests.

• Triquetral shear test - direct pressure on the triquetrum; pain suggests triquetral pathology, and the test is specific for triquetral injury
• Ballottement test - assesses lunotriquetral stability against the other side; a positive test means LT instability
• Watson (scaphoid shift) test - should be negative; if positive, consider an additional carpal injury
• ECU subluxation test - supinate and ulnar deviate the wrist; extensor carpi ulnaris may be injured as well

Ulnar-sided wrist pain after a fall has a broad differential. The triquetral fracture must be distinguished from the conditions below, several of which can coexist with it.

Radiographs. PA, lateral and oblique views. The lateral is the essential view for a dorsal chip, which is often missed on the PA: look for a small osseous fragment dorsal to the carpal silhouette, sitting dorsal to the lunate and usually at the level of the triquetrum. It is best identified with true lateral positioning and may be overlooked if not specifically sought. This is a common exam presentation. The lateral may, in turn, miss a body fracture.

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The PA view. Often normal with an isolated dorsal chip, but it may show a body fracture, and it is where carpal alignment and the scapholunate and lunotriquetral intervals are assessed. Signs of an associated injury:

• Scapholunate widening (SL injury)
• LT overlap or widening
• Disruption of the carpal arcs
• A DISI or VISI pattern on the lateral

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CT. CT gives fracture detail, at the cost of radiation and expense. Indications:

• A suspected body fracture that is not clear on radiographs
• Surgical planning for a displaced fracture
• Assessment of comminution
• Evaluation for perilunate injury

It shows the orientation of the fracture line, fragment size and displacement, articular involvement and associated carpal injuries.

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MRI. For a suspected ligamentous injury, the LT ligament and the TFCC, and for an occult fracture not seen on radiographs or CT, which shows as bone marrow oedema. It also shows associated soft-tissue injury; cost and availability limit it.

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Bone scan. Rarely needed. It may detect an occult fracture but has been superseded by MRI for most indications.

Algorithm

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Most triquetral fractures are managed conservatively with excellent results. The decision to operate rests on the fracture pattern and the associated injuries.

After a dorsal chip. Symptomatic non-union is the most common complication, presenting as persistent dorsal wrist pain. The fragment may also abrade the overlying extensor tendons, EDC or EDM most commonly, causing tendon pain or snapping. A large fragment can block extension and produce mechanical symptoms with wrist motion (dorsal impingement). Both are treated by excising the fragment.

After a body fracture. Malunion is rare with appropriate treatment, but it may alter carpal kinematics and lead to secondary arthritis. Non-union is more common than with dorsal chips, is associated with inadequate immobilisation, and may require bone grafting.

Post-traumatic arthritis is uncommon with an isolated triquetral fracture, more common with associated injuries, and may require a salvage procedure. Lunotriquetral instability can develop after a body fracture, and the LT ligament may be injured at the time of fracture. It presents with ulnar wrist pain and clicking and is treated by LT repair or fusion.

After surgery.

• Wound - infection (rare), dehiscence, scar sensitivity
• Hardware - screw prominence or K-wire migration, which may require removal
• Tendon - ECU or EDM at risk; usually prevented with careful technique, and repaired if identified intraoperatively

After fragment excision. A soft dressing and volar splint for 1-2 weeks, with immediate finger motion and elevation. Wrist range of motion begins early, at 2-4 weeks, when the splint may be discontinued and light activities resume. From week 4, full range and strengthening with a return to normal activities without restriction, full activity at 4-6 weeks.

After body fracture ORIF.

• Week 0-2 - volar splint in neutral, immediate finger motion, elevation and wound care; sutures out at 10-14 days
• Week 2-6 - removable splint and gentle wrist range of motion, begun at 2-4 weeks depending on stability; avoid loading and forceful grip
• Week 6-12 - discontinue the splint and begin progressive strengthening; K-wires, if used, are removed at 6 weeks; return to activities at 8-12 weeks

Follow-up.

Most patients achieve full recovery with straightforward rehabilitation.

Dorsal chips. Over 95% heal with conservative treatment, with union typically at 4-6 weeks, and a fibrous union may be asymptomatic. Range of motion recovers to 95-100% of normal, grip strength returns in full, and patients return to their previous activity level with high satisfaction; persistent symptoms are rare. A symptomatic non-union is easily treated by excision, with excellent results.

Body fractures. Healing is good with appropriate treatment, union typically at 6-8 weeks. Anatomic reduction gives good outcomes, although some residual stiffness may remain; the result depends on the associated injuries, and most return to their previous activity. Perilunate spectrum injuries carry a worse prognosis: LT instability may persist and additional procedures may be required.

Prognostic factors.

• Favourable - dorsal chip pattern, isolated injury, early treatment, compliant patient
• Unfavourable - displaced body fracture, associated perilunate injury, delayed diagnosis, high-energy mechanism

Return to activity after conservative treatment:

• Sedentary work - 1-2 weeks, in the splint
• Light manual work - 6-8 weeks
• Heavy manual work - 8-12 weeks
• Contact sports - 8-12 weeks

After surgery the timelines are similar and may be slightly longer after ORIF of a body fracture; athletes return at 3-4 months.

Global Epidemiology (Registry & Population Evidence)

There is no dedicated triquetral-fracture trial registry; the strongest evidence comes from national fracture registries and large carpal-fracture series that report relative frequency, demographics and treatment patterns.

Registry and cohort data are consistent across Europe and North America: the triquetrum is the second most commonly fractured carpal bone, the dorsal cortical (chip) pattern predominates, and the population is skewed towards young adult men. Plain radiographs substantially under-detect these fractures, so persistent clinical suspicion should drive further imaging.

Guideline & Society Positions

No single national society publishes a stand-alone triquetral-fracture guideline; management is governed by general carpal-fracture and wrist-trauma principles. The table below summarises where authoritative guidance is drawn from across major bodies.

Practice Variation

• Consistent across systems: conservative management (short-arm cast or splint, typically 3 to 6 weeks) is standard worldwide for isolated dorsal chip and undisplaced body fractures, reflecting Level IV evidence of reliable union without instability or avascular necrosis.
• Variation: immobilisation duration varies (3 weeks in the Höcker series versus the more commonly quoted 4 to 6 weeks); thresholds for CT after a normal radiograph differ by access and local protocol.
• Surgery: reserved for displaced body fractures, perilunate spectrum injuries and symptomatic dorsal chip non-union (fragment excision) in all systems.

Understanding these key concepts will help with exam success.

The evidence supports conservative management for most triquetral fractures with excellent expected outcomes.