Hamate Fracture
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Clinically Relevant Anatomy
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The hamate bone is a triangular bone located in the distal carpal row and is situated on the ulnar side. He is composed of a body and a hook. Hamate fractures constituted about 2% of all carpal fractures.[1][2] They are classified as type I fractures involving the hook and type II fractures involving the body. Type I fractures are more common than type II fractures.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
The hamate is bordered proximally by the pisiform and the lunate in the proximal carpal row, radially by the capitate, and distally by the bases of the fourth and fifth metacarpals.[3]
The Guyon canal carries the ulnar artery and nerve, for this reason hook fractures should suggest a high probability of ulnar artery and nerve damage.
Mechanism of Injury / Pathological Process
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Hamate fractures are most often seen in racquet, club or bat sports.
Racquet sports, like tennis, cause impact of the grip against the hook of the hamate of the dominant hand where as in golf, baseball and hockey the club will impact against the hamate in the non-dominant hand.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Type I fractures involving the hook of the hamate can occur via several different mechanisms:Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive titleCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive titleCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
- Repeated micro trauma
- Direct trauma
- Indirect trauma
Repeated micro trauma to the hook in sports involving swinging clubs, bats, or racquets can result in a hook stress fracture. These are usually occurring in the non-dominant hand.
Direct trauma can be applied during sports when the butt of the club rests on the hamate and the force of the swing is then transmitted directly to the bone. A fall onto the outstretch hand or fall on the hand while holding an object but is also seen in particular sporting activities.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Indirect trauma can be applied to the hook through its muscular and ligamentous attachments. This can occur either when falling on a hyperextended wrist or during power grips.[1]
Type II fractures involving the body of the hamate always requires a direct force.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title These fractures are typically associated with high-energy, direct-force trauma or contusion injuries.
Clinical Presentation[edit | edit source]
Point tenderness on the hypothenar and weak grip are characteristics of hamate fractures. Patients typically present with pain and tenderness over the hamate. Ulnar and median neuropathy can also be seen, as well as rare injuries to the ulnar artery. Displaced hamate fragments and hematoma as well as nonunion of the hook of the hamate can lead to neuropathy of the deep branch of the ulnar nerve, lesion of the median nerve, or even rupture of deep flexor tendons IV and V. Decreased sensation or weakness may be due to ulnar or median nerve injury. The fracture fragments may injure the nerves directly or swelling and inflammation may injure them indirectly.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title[1]Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive titleCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
With a fracture of the hook of the hamate there might be pain on the dorso-ulnar aspect of the wrist.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Diagnostic Procedures[edit | edit source]
An oblique x-ray view or a carpal tunnel view should be considered as part of the initial diagnostic investigations. It can help with diagnosis and give further important information to aid appropriate management.[3] Usually they are negative, a CT scan of the wrist in the “praying position” is the imaging modality of choice.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive titleCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title A high density CT scan with the wrists in the “praying position” allows comparison between the two wrists. It is reported to have a sensitivity of 100%, specificity of 98.4%, and accuracy of 97.2% and is the radiographic technique of choice in the diagnosis of hook of the hamate fractures.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Fractures of the body of the hamate are difficult to diagnose. AP (anteroposterior), lateral and oblique views are more useful for diagnosis of body fractures than for hook fractures. The oblique and lateral views are the most useful. When routine films are negative and when a fracture is highly suspected, a CT scan should be taken.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title Assessments of the degree of angulations, reduction and articular incongruence or subluxation are the important imaging findings.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
The hook of the hamate pull test (HPPT) is a clinical test for diagnosing a hook of hamate fracture.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Outcome Measures[edit | edit source]
Management / Interventions
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Conservative option for nondisplaced fractures is a short-arm cast. The cast should immobilize the metacarpophalangeal joints of the fourth and fifth fingers and be a thumb spica to decrease micrononuinion at the hook. 2 Cast should be worn for 6-8 weeks to prevent nonunion. If pain is still present after cast removal, then excision for nonunion is the treatment of choice.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
In the most studies, surgical treatment (fragment excision and open reduction and internal fixation (ORIF)) of a hamate fracture has a higher success rate than after conservative treatment.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive titleCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive titleCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Low-intensity ultrasound has been reported to be useful in promoting fracture healing, it accelerates the normal fracture repair process.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Ultrasound treatment might be useful for nonunion caused by a repeated stress, the ultrasound is a treatment for nonunion of the hook of the hamate and is an option in various treatment methods.Cite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title
Differential Diagnosis
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Key Evidence[edit | edit source]
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References[edit | edit source]
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- ↑ 1.0 1.1 1.2 Rainer Schmitt; Ulrich Lanz; Diagnostic imaging of the hand; THIEME; 2008
- ↑ Rosemary Prosser,W. Bruce Conolly; Rehabilitation of the hand and upper limb; 2003
- ↑ 3.0 3.1 Vishal H Borse, James Hahnel, Adnan Faraj; Lessons to be learned from a missed case of Hamate fracture: a case report; Journal of Orthopaedic Surgery and Research; 2010 Aug 27;5:64. (B)
