- Email: [email protected]
Hamate-metacarpal fracture dislocation
The Journal of Emergency Medicine, Vol 10,pp 565468,199.T
HAMATE-METACARPAL
Printed in the USA
Copyright 0 1992 Pergamon Press Ltd.
FRACTURE DISLOCATION
Harry Davidson Kerr,
MD, FACEP
Emergency Department, Columbia Hospital, Milwaukee, Wisconsin Reprint Address: Harry D. Kerr, MD, FACEP, 4641 North Ardmore Avenue, Whitefish Bay, WI 53211
0 Abstract-A patient is described who punched a brick wail with his clenched fist and sustained a fracture of the body of the hamate with dislocation of the ring and little finger metacarpals. He was treated successfully with surgery. Thls is a rare injury that is frequently mlssed on the initial presentation and should be considered ln the differential diagnosis of posttraumatlc ulnar-sided hand pain. 0 Keywords- hamate fracture; metacarpal dislocation; wrist fracture-dislocation; wrist trauma
INTRODUCTION
A common emergency department (ED) problem is presented by the patient who complains of hand pain and swelling after having punched a hard surface in a fit of rage or frustration. The usual diagnostic entity to explain pain or swelling on the ulnar aspect of the hand is a fracture of the little finger metacarpal. However, other more subtle injuries may occur. The patient described presented with an unusual and complicated carpal fracture-dislocation.
CASE REPORT
A 32-year-old right-handed male laborer struck a brick wall with his right fist. He noted immediate pain in the hand but discounted it until the following morning when marked swelling over the ulnar dorsum prompted him to seek medical attention. Pain was increased by any movement of the ring and little fingers. He noted no paresthesias. Abnormal physical examination findings were confined to the right hand and wrist. The ring and RECEIVED: 9 May 1991; FINAL SUBMISSION RECEIVED: 30 ACCEPTED: 2 December 1991
little fingers were held in extension. There was no ecchymosis. The ulnar aspect of the hand and wrist was swollen near the base of the little finger metacarpal. There was point tenderness at the dorsal ulnar carpus and base of the ring and little finger metacarpals. Sensibility to pin, two-point discrimination to 5 millimeters, and touch were intact. Capillary refill was normal. Radiographs (Figures 1 and 2) showed a dorsally displaced fracture of the body of the hamate on the ulnar side of the hamulus with dorsal and radial displacement of the base of the little finger metacarpal. Subluxation of the bases of the ring finger and little finger metacarpals was noted. Orthopedic consultation was obtained and the injury was repaired by open reduction and internal fixation. A Kirschner wire was used to fix the ring and little finger metacarpals to the capitate. A lag screw was used to unite the hamate (Figure 3). Good function without pain was noted at 3-month follow-up.
DISCUSSION Wrist injuries are a common and often challenging problem for emergency physicians. Wrist anatomy is exceedingly complex and much of the inter-workings of the carpal bones has yet to be explained (1). Clenched fist trauma to the ulnar aspect of the hand and wrist usually results in soft tissue injury or ring or little finger metacarpal fractures. Carpometacarpal (CMC) dislocations, disruption of the extensor tendon mechanism, metacarpophalangeal (MCP) joint capsule rupture, and hamate fractures have also been noted in association with clenched fist trauma (233). October 1991;
07364679192 $5.00 + .OO
Harry D. Kerr
566
The hamate is a wedge-shaped bone that articulates with both the ring and the little finger metacarpals, the triquetrum, the capitate, and the lunate. Fractures of the hamate with or without CMC dislocation are rare (4). Dunn reported that they occur in about 2% of carpal bone fractures (5). Milch classified hamate fractures into those involving the hamulus (hook) and those involving the body (6). The majority involve the hamulus and occur as a result of direct violence or a fall with the wrist dorsiflexed (7). The body may be fractured by a direct crushing injury or as a result of axial loading such as that which occurs when the fist strikes an unyielding object (Figure 4) (8-l 1). In these injuries, with the wrist in ulnar deviation and palmar flexed, force is transmitted through the longitudinal axis of the ring and little finger metacarpals to the hamate. Fractures or dislocations of the ring and little finger metacarpals may also occur. Physical examination of patients with hamate fractures is often unrevealing. Despite differing
Figure 2. Lateral radiograph.
Figure 1. PA radiograph showing hamate fracture and subluxation of the bases of the ring and little finger metacarpals.
mechanisms of injury, the physical findings in body or hamulus fractures may be similar (12). Swelling and diffuse pain on the ulnar aspect of the wrist will be present. Pain upon direct palpation of the hypothenar eminence may be found and should prompt evaluation of ulnar nerve function as well as consideration of the possibility of hamate fracture. The deep palmar branches of the ulnar artery and nerve circle the hamulus on the ulnar side. The tunnel of Guyon is situated between the hamulus and the pisiform bone. The ulnar nerve innervates all interosseous muscles, the adductor pollicis muscle, the long finger and ring finger lumbrical muscles, and the deep head of the flexor pollicis brevis. The sum of ulnar motor nerve injury is loss of grip strength and impairment of fine motor control. Ulnar nerve injury has been reported in fractures of the body and the hook of the hamate (13). Radiographic studies should include the standard posterior-anterior (PA), lateral, and oblique views. Fisher and associates describe an approach to radiograph interpretation when CMC dislocation is sus-
Hamate Fracture
567
Figure 4. Schematic lateral view of the clenched fist from the ulnar aspect. Depending on the angle of impact, axial force can shear or split the body of the hamate. (1) Ring finger metacarpal; (2) Llttle finger metacarpal; (3) Body of the hamate; (4) Hamulus.
Figure 3. Postoperative oblique view.
petted (14). In ring and little finger metacarpal dislocations or fracture dislocations, the normal parallel relationship of opposing joint surfaces is lost on the PA view. The lateral view, however, normally demonstrates CMC fracture dislocations and direction of displacement most definitively. If the diagnosis remains in question after routine radiographs, AP, 30degree pronated views, and tomograms should be obtained. CMC joint injury is rare and frequently subtle on routine radiographs. The majority of these injuries are missed on initial evaluation (3,B). Three-dimensional computed tomography (CT scan), developed in 1983, has been advocated as of-
fering a much better approach to assessment of bony abnormalities in the wrist, in particular displaced fractures, complicated fracture-dislocations, and identification of small bony fragments (15). The CT scan, however, does not have a place in the initial evaluation of such injuries. Emergency treatment of these injuries consists of adequate splinting, pain relief, and prompt consultation. Hall suggests splinting and reinforcement of the need for follow-up (16). Definitive treatment usually requires open reduction and internal fixation to insure proper grip strength and to avoid subsequent posttraumatic arthritis (8,17).
SUMMARY A fracture-dislocation involving the hamate and the ring and little finger metacarpals is a rare injury that can result from blunt trauma such as that resulting from a punch striking an unyielding object. This injury is often missed on initial presentation, which emphasizes the need for compulsive diagnostic evaluation and careful follow-up.
REFERENCES 1. Green DP. Dislocations and ligamentous injuries in the wrist. In: Evarts CMc, (ed). Surgery of the musculoskeletal system pp 2:185-2:232. New York: Churchill Livingstone; 1983. 2. Posner MA, Ambrose L. Boxer’s knuckle-dorsal capsular rupture of the metacarpophalangeal joint of a finger. J Hand Surg. 1989;14A:229-36. 3. Garcia-Elias M, Bishop AT, Dobyns JH, Cooney WP, Lindscheid RL. Transcarpal carpometacarpal dislocations, excluding the thumb. J Hand Surg. 1990;15A:531-40. 4. Kimura H, Kamura S, Akai M, Ohno T. An unusual coronal fracture of the body of the hamate bone. J Hand Surg. 1988; 13A:743-5.
5. Dunn AW. Fractures and dislocations of the carpus. Surg Clin North Am. 1972;52:1513-19. 6. Milch H. Fracture of the hamate bone. J Bone Joint Surg. 1934;16:459-62. 7. Gittien WB. Hamulus fracture. Ann Emerg Med. 1984;13: 122-5. 8. Cain JE, Shepler TR, Wilson MR. Hametometacarpal fracture-dislocation: classification and treatment. J Hand Surg. 1987;12A(2 Pt 1):762-67. 9. Loth TS, McMillan MD. Coronal dorsal hamate fractures. J Hand Surg. 1988;13A:616-18. 10. Freeland AE, Finley JS. Displaced dorsal oblique fracture Of
568 the hamate treated with a cortical mini lag screw. J Hand Surg. 19861 lA:656-8. 11. Thomas AP, Birch R. An unusual hamate fracture. Hand. 1983;15:281-6. 12. Taleisnik J. Fractures of the carpal bones. In: Green DP, (ed). Operative hand surgery; vol 1 (pp 688-90). New York: Churchill Livingstone; 1982. 13. Howard FM. Ulnar nerve palsy in wrist fractures: fracture of the hamate bone. J Bone Joint Surg. 1961;43: 1197-201. 14. Fisher MR, Rogers LF, Hendrix RW. Systematic approach to
Harry D. Kerr identifying fourth and fifth carpometacarpal joint dislocations. AJR. 1983;140:319-24. 15. Nakamura P, Horil E, Tanaka Y, Imaeda T, Hayakawa N. Three-dimensional CT imaging for wrist disorders. J Hand Surg. 1989;14B:53-8. 16. Hall RF. Treatment of metacarpal and phalangeal fractures in noncompliant patients. Clin Orthop. 1987;214:31-6. 17. Bora FW, Didizian NH. The treatment of injuries to the carpometacarpal joint of the little finger. J Bone Joint Surg. 1974;56A:1459-63.
HAMATE-METACARPAL
Printed in the USA
Copyright 0 1992 Pergamon Press Ltd.
FRACTURE DISLOCATION
Harry Davidson Kerr,
MD, FACEP
Emergency Department, Columbia Hospital, Milwaukee, Wisconsin Reprint Address: Harry D. Kerr, MD, FACEP, 4641 North Ardmore Avenue, Whitefish Bay, WI 53211
0 Abstract-A patient is described who punched a brick wail with his clenched fist and sustained a fracture of the body of the hamate with dislocation of the ring and little finger metacarpals. He was treated successfully with surgery. Thls is a rare injury that is frequently mlssed on the initial presentation and should be considered ln the differential diagnosis of posttraumatlc ulnar-sided hand pain. 0 Keywords- hamate fracture; metacarpal dislocation; wrist fracture-dislocation; wrist trauma
INTRODUCTION
A common emergency department (ED) problem is presented by the patient who complains of hand pain and swelling after having punched a hard surface in a fit of rage or frustration. The usual diagnostic entity to explain pain or swelling on the ulnar aspect of the hand is a fracture of the little finger metacarpal. However, other more subtle injuries may occur. The patient described presented with an unusual and complicated carpal fracture-dislocation.
CASE REPORT
A 32-year-old right-handed male laborer struck a brick wall with his right fist. He noted immediate pain in the hand but discounted it until the following morning when marked swelling over the ulnar dorsum prompted him to seek medical attention. Pain was increased by any movement of the ring and little fingers. He noted no paresthesias. Abnormal physical examination findings were confined to the right hand and wrist. The ring and RECEIVED: 9 May 1991; FINAL SUBMISSION RECEIVED: 30 ACCEPTED: 2 December 1991
little fingers were held in extension. There was no ecchymosis. The ulnar aspect of the hand and wrist was swollen near the base of the little finger metacarpal. There was point tenderness at the dorsal ulnar carpus and base of the ring and little finger metacarpals. Sensibility to pin, two-point discrimination to 5 millimeters, and touch were intact. Capillary refill was normal. Radiographs (Figures 1 and 2) showed a dorsally displaced fracture of the body of the hamate on the ulnar side of the hamulus with dorsal and radial displacement of the base of the little finger metacarpal. Subluxation of the bases of the ring finger and little finger metacarpals was noted. Orthopedic consultation was obtained and the injury was repaired by open reduction and internal fixation. A Kirschner wire was used to fix the ring and little finger metacarpals to the capitate. A lag screw was used to unite the hamate (Figure 3). Good function without pain was noted at 3-month follow-up.
DISCUSSION Wrist injuries are a common and often challenging problem for emergency physicians. Wrist anatomy is exceedingly complex and much of the inter-workings of the carpal bones has yet to be explained (1). Clenched fist trauma to the ulnar aspect of the hand and wrist usually results in soft tissue injury or ring or little finger metacarpal fractures. Carpometacarpal (CMC) dislocations, disruption of the extensor tendon mechanism, metacarpophalangeal (MCP) joint capsule rupture, and hamate fractures have also been noted in association with clenched fist trauma (233). October 1991;
07364679192 $5.00 + .OO
Harry D. Kerr
566
The hamate is a wedge-shaped bone that articulates with both the ring and the little finger metacarpals, the triquetrum, the capitate, and the lunate. Fractures of the hamate with or without CMC dislocation are rare (4). Dunn reported that they occur in about 2% of carpal bone fractures (5). Milch classified hamate fractures into those involving the hamulus (hook) and those involving the body (6). The majority involve the hamulus and occur as a result of direct violence or a fall with the wrist dorsiflexed (7). The body may be fractured by a direct crushing injury or as a result of axial loading such as that which occurs when the fist strikes an unyielding object (Figure 4) (8-l 1). In these injuries, with the wrist in ulnar deviation and palmar flexed, force is transmitted through the longitudinal axis of the ring and little finger metacarpals to the hamate. Fractures or dislocations of the ring and little finger metacarpals may also occur. Physical examination of patients with hamate fractures is often unrevealing. Despite differing
Figure 2. Lateral radiograph.
Figure 1. PA radiograph showing hamate fracture and subluxation of the bases of the ring and little finger metacarpals.
mechanisms of injury, the physical findings in body or hamulus fractures may be similar (12). Swelling and diffuse pain on the ulnar aspect of the wrist will be present. Pain upon direct palpation of the hypothenar eminence may be found and should prompt evaluation of ulnar nerve function as well as consideration of the possibility of hamate fracture. The deep palmar branches of the ulnar artery and nerve circle the hamulus on the ulnar side. The tunnel of Guyon is situated between the hamulus and the pisiform bone. The ulnar nerve innervates all interosseous muscles, the adductor pollicis muscle, the long finger and ring finger lumbrical muscles, and the deep head of the flexor pollicis brevis. The sum of ulnar motor nerve injury is loss of grip strength and impairment of fine motor control. Ulnar nerve injury has been reported in fractures of the body and the hook of the hamate (13). Radiographic studies should include the standard posterior-anterior (PA), lateral, and oblique views. Fisher and associates describe an approach to radiograph interpretation when CMC dislocation is sus-
Hamate Fracture
567
Figure 4. Schematic lateral view of the clenched fist from the ulnar aspect. Depending on the angle of impact, axial force can shear or split the body of the hamate. (1) Ring finger metacarpal; (2) Llttle finger metacarpal; (3) Body of the hamate; (4) Hamulus.
Figure 3. Postoperative oblique view.
petted (14). In ring and little finger metacarpal dislocations or fracture dislocations, the normal parallel relationship of opposing joint surfaces is lost on the PA view. The lateral view, however, normally demonstrates CMC fracture dislocations and direction of displacement most definitively. If the diagnosis remains in question after routine radiographs, AP, 30degree pronated views, and tomograms should be obtained. CMC joint injury is rare and frequently subtle on routine radiographs. The majority of these injuries are missed on initial evaluation (3,B). Three-dimensional computed tomography (CT scan), developed in 1983, has been advocated as of-
fering a much better approach to assessment of bony abnormalities in the wrist, in particular displaced fractures, complicated fracture-dislocations, and identification of small bony fragments (15). The CT scan, however, does not have a place in the initial evaluation of such injuries. Emergency treatment of these injuries consists of adequate splinting, pain relief, and prompt consultation. Hall suggests splinting and reinforcement of the need for follow-up (16). Definitive treatment usually requires open reduction and internal fixation to insure proper grip strength and to avoid subsequent posttraumatic arthritis (8,17).
SUMMARY A fracture-dislocation involving the hamate and the ring and little finger metacarpals is a rare injury that can result from blunt trauma such as that resulting from a punch striking an unyielding object. This injury is often missed on initial presentation, which emphasizes the need for compulsive diagnostic evaluation and careful follow-up.
REFERENCES 1. Green DP. Dislocations and ligamentous injuries in the wrist. In: Evarts CMc, (ed). Surgery of the musculoskeletal system pp 2:185-2:232. New York: Churchill Livingstone; 1983. 2. Posner MA, Ambrose L. Boxer’s knuckle-dorsal capsular rupture of the metacarpophalangeal joint of a finger. J Hand Surg. 1989;14A:229-36. 3. Garcia-Elias M, Bishop AT, Dobyns JH, Cooney WP, Lindscheid RL. Transcarpal carpometacarpal dislocations, excluding the thumb. J Hand Surg. 1990;15A:531-40. 4. Kimura H, Kamura S, Akai M, Ohno T. An unusual coronal fracture of the body of the hamate bone. J Hand Surg. 1988; 13A:743-5.
5. Dunn AW. Fractures and dislocations of the carpus. Surg Clin North Am. 1972;52:1513-19. 6. Milch H. Fracture of the hamate bone. J Bone Joint Surg. 1934;16:459-62. 7. Gittien WB. Hamulus fracture. Ann Emerg Med. 1984;13: 122-5. 8. Cain JE, Shepler TR, Wilson MR. Hametometacarpal fracture-dislocation: classification and treatment. J Hand Surg. 1987;12A(2 Pt 1):762-67. 9. Loth TS, McMillan MD. Coronal dorsal hamate fractures. J Hand Surg. 1988;13A:616-18. 10. Freeland AE, Finley JS. Displaced dorsal oblique fracture Of
568 the hamate treated with a cortical mini lag screw. J Hand Surg. 19861 lA:656-8. 11. Thomas AP, Birch R. An unusual hamate fracture. Hand. 1983;15:281-6. 12. Taleisnik J. Fractures of the carpal bones. In: Green DP, (ed). Operative hand surgery; vol 1 (pp 688-90). New York: Churchill Livingstone; 1982. 13. Howard FM. Ulnar nerve palsy in wrist fractures: fracture of the hamate bone. J Bone Joint Surg. 1961;43: 1197-201. 14. Fisher MR, Rogers LF, Hendrix RW. Systematic approach to
Harry D. Kerr identifying fourth and fifth carpometacarpal joint dislocations. AJR. 1983;140:319-24. 15. Nakamura P, Horil E, Tanaka Y, Imaeda T, Hayakawa N. Three-dimensional CT imaging for wrist disorders. J Hand Surg. 1989;14B:53-8. 16. Hall RF. Treatment of metacarpal and phalangeal fractures in noncompliant patients. Clin Orthop. 1987;214:31-6. 17. Bora FW, Didizian NH. The treatment of injuries to the carpometacarpal joint of the little finger. J Bone Joint Surg. 1974;56A:1459-63.