After sustaining a fall the previous evening, Mr. A, a man aged 29 years, presented to the emergency department (ED). He reported that he tripped over his child’s toy and that his right hand broke his fall; he landed on a clenched fist.
On presentation, Mr. A described pain in the right hand, and there was significant ecchymosis and swelling. The patient reported no other injuries as a result of the fall.
1. History
Mr. A did not report any personal or family medical history. He did report a nicotine habit, having smoked one pack of cigarettes per day for 12 years, but denied any alcohol or drug use. He also reported that he does not take any daily prescription or OTC medication.
Continue Reading
2. Examination
Mr. A had significant edema on the dorsum and palmar surfaces of his right hand, mostly over the carpals and proximal metacarpals. There was ecchymosis noted over the palm, thena, and hypothenar eminences. The patient had limited range of motion in his metacarpophalangeal joints due to pain. There was also very limited right-wrist flexion and extension due to pain and swelling.
Mr. A was most tender over the hypothenar eminence. The right radial pulse was +2 and regular. Capillary refill of the right fingers was brisk. Mr. A had good sensation of all right-hand fingers, dorsum and palm of the hand. He denied any numbness or tingling.
3. Differential Diagnosis
There are several diagnoses to consider with this injury and physical presentation: (1) metacarpal head, neck or shaft fractures; (2) carpal fractures; (3) joint dislocation; (4) hand contusion; (5) tendon, ligament or muscle injury; (6) cellulitis; or (7) deep tissue infection. Given this particular history, infection is unlikely. However, if the fall resulted in an open wound, infection is possible.
The physical exam in this case did not show any evidence of open injury, erythema, warmth or fluctuance, so infection was ruled out. Metacarpal and carpal fracture, and joint dislocations should be suspected with this mechanism of injury and physical presentation. Plain radiographs should be obtained to evaluate for this. Fractures of the fifth metacarpal neck, usually referred to as a Boxer’s fracture, are a very common injury with punch or axial force injuries.1
If hand and wrist x-rays are negative for bone or joint injury or contusion, then tendon, ligament or muscle injuries should be considered.
4. Radiographic Findings
Initially, x-rays of the right wrist and hand (taken while the patient was in the ED) were read as negative for any acute fracture, bone, joint or soft tissue abnormality (Figure 1).
Still, the ED physician suspected a fracture, due to the amount of swelling and ecchymosis present in Mr. A’s hand. A CT scan was obtained to rule out any occult fracture or bone/joint injury. The scan showed evidence of an acute, comminuted, coronal fracture of the hamate with displacement of the fragments of about 5 mm (Figure 2). The hand surgeon consulted also noted dislocation of the right fourth and fifth carpometacarpal (CMC) joints.
5. Diagnosis and Treatment
Mr. A was diagnosed with right fourth and fifth CMC dislocations with fracture of the hamate. The patient was placed in a plaster volar splint in the ED and instructed to follow up in the hand trauma clinic in two days time. Repeat x-rays obtained at the follow-up visit demonstrated no further dislocation or displacement of the fracture.
Treatment options were discussed with the patient and surgical fixation was scheduled. Mr. A underwent open reduction and internal fixation of his hamate fracture and CMC dislocations (Figure 3). Fracture fixation was obtained using two lag screws, and the CMC dislocations were reduced using three Kirschner wires.
6. Discussion
The hamate is a carpal bone that has two components: the body and the hook. It articulates with the triquetrum proximally and the fourth and fifth metacarpals distally.2 Hamate fractures consist of about 2% of all carpal fractures.1 Of the two types of hamate fractures, the most common are fractures of the hook. Because of the hook’s prominence on the palmar side of the hand, it is often fractured as a result of a direct blow during sports that involve holding a racket or a bat. The second, and much less common, type is a fracture through the body of the hamate.3 The fractures of the body of the hamate have been further divided into four major categories: proximal pole fractures, medial tuberostiy fractures, sagittal oblique fractures, and dorsal coronal fractures.1 Coronal fractures usually occur from a punch injury or from axial forces being applied through the metacarpals.1, 3 Dislocation or subluxation of the CMC joint may also be associated with this fracture type.2
Coronal fractures of the hamate are frequently missed on plain radiographs because the hamate-metacarpal joint is not easily seen. There can also be overlap of the carpals and metacarpals in anteroposterior and lateral views.2 CT scan should be considered in cases where there is swelling, ecchymosis, or continued hand and/or wrist pain with negative x-rays.4
Delays in the diagnosis and treatment of these types of fractures can lead to poor outcomes, including nonunion, residual subluxation of the CMC joints, pain, arthritis, loss of grip strength, and decreased range of motion in the wrist.1,5
Non-displaced fractures of the body of the hamate can be treated conservatively with splinting/casting and immobilization.1 Open reduction and internal fixation is usually the best treatment option for displaced fractures of the hamate body. This includes fracture fixation with compression screws or an H-plate, as well as joint stabilization using Kirschner wires if necessary.1
In the primary-care setting, if a patient presents with a painful and swollen hand, diagnoses to consider would be fracture; dislocation; hand contusion; ligament; tendon, or muscle injury; cellulitis; or deep tissue infection. A thorough history is needed to determine the mechanism of injury and to determine whether or not an open injury occurred. This includes puncture wounds, animal/insect bites, lacerations, or abrasions. Prompt hand-surgery referral is appropriate for any suspected fractures, dislocations, tendon or ligamentous injury, or hand infection to ensure proper management and to prevent complications.
Leah Favret, MSN, CNP, works as a nurse practitioner with the hand and orthopedic trauma service at Riverside Methodist Hospital in Columbus, Ohio.
References
1. Wolfe SW, Hotchkiss RN, Pederson WC, Kozin SH. Green’s Operative Hand Surgery. 6th ed. Philadelphia, Pa.: Elsevier;2011:686-689.
2. Ebraheim NA, Skie MC, Savolaine ER, Jackson TW. Coronal fracture of the body of the hamate. J Trauma. 1995;38:169-174.
3. Bucholz RW, Court-Brown CM, Heckman JD, Tornet P. Rockwood and Green’s Fractures in Adults. 7th ed. Philadelphia, Pa.: Lippincott Williams & Wilkins;2010:807-808.
4. Gella S, Borse V, Rutten E. Coronal fractures of the hamate: are they rare or rarely spotted? J Hand Surg Eur Vol. 2007;32:721-722.
5. Wharton DM, Casaletto JA, Choa R, Brown DJ. Outcome following coronal fractures of the hamate. J Hand Surg Eur Vol. 2010;35:146-149.
