Orthopedics

Case Reports 

Fracture Dislocation of Carpometacarpal Joints: A Missed Injury

Abstract

Fracture dislocation of the carpometacarpal joints on the ulnar side of the hand is an uncommon injury. These are high-energy injuries seen in motorcyclists and boxers. The mechanism of injury involves violent, forceful dorsiflexion of the wrist combined with longitudinal impact on the closed hand. This article reports a case of fracture of the base of the middle finger with dislocation of the ring and little finger carpometacarpal joints. On first examination, a diagnosis of isolated, minimally-displaced, middle-metacarpal base fracture was made and deemed suitable for nonoperative management. The hand was splinted in a plaster-of-Paris slab. Later, a true lateral radiograph was obtained, which showed the exact nature of the injury. The fracture was successfully treated with closed reduction under general anesthesia and transfixation using Kirschner wires. Functional results were excellent with return to work at 10 weeks and excellent grip strength at 14 weeks. This injury may be missed in an acute setting in a busy accident and emergency unit. Swelling around the wrist with shortening of the knuckle should alert the clinician towards the possibility of such an injury. On routine anteroposterior view, overlap of joint surfaces, loss of parallelism, and asymmetry at the carpometacarpal joints should make one suspect the possibility of a subtle carpometacarpal injury. This article highlights the importance of a high index of suspicion, a true lateral radiograph, and careful evaluation of radiographs in diagnosing these injuries. Intensive postoperative physiotherapy is vital to achieving a satisfactory outcome.

Fracture dislocation of carpometacarpal joints on the ulnar side of the hand is an uncommon injury.1 Diagnosis of this unusual form of injury requires a high index of suspicion, careful clinical examination, and good radiographs.2 They are high-energy injuries seen in motorcyclists and boxers with a mechanism that involves violent, forceful palmarflexion of the wrist combined with longitudinal impact on the closed hand.3 Dislocation may be in a palmar or dorsal direction, and associated fractures of adjacent metacarpal or carpal bones may present.4

Carpometacarpal injuries account for <1% of hand injuries and may be overlooked or missed.5 Disability of the hand is severe when untreated or in those who received delayed treatment.6 The carpometacarpal joints of the hand are arthrodial diarthroses (gliding joints). The bases of the metacarpals articulate with the distal row of the carpal bones and with each other in an interlocking mechanism. Intermetacarpal and carpometacarpal ligaments, as well as ligaments of the wrist flexors and extensors that insert into the bases of the second, third, and fifth metacarpals, further reinforce the joints.5

A 26-year-old man presented with right wrist pain after a fall on his outstretched hand. On examination, marked swelling of the wrist with significant bruising over the dorsum of the wrist and hand were found. He was globally tender around the wrist and over the metacarpals. He was unable to move his fingers actively due to pain, but he had good sensation and vascularity in his fingers.

Radiographs of the hand (Figures 1, 2) showed a minimally displaced middle metacarpal base fracture. The fracture was deemed suitable for nonoperative management. The hand was splinted in a plaster-of-Paris back slab.

On second examination, the patient was clinically and radiologically reassessed. The hand was still swollen and diffusely tender over the dorsum. Review of the initial radiographs showed loss of parallelism and symmetry at the carpometacarpal joints of the ring and little fingers with overlap of joint surfaces. Due to clinical suspicion, a true lateral radiograph was obtained. This revealed a dorsoulnar dislocation of the ring and little finger carpometacarpal joints along with a fracture of the third metacarpal base (Figure 3).

Under general…

Abstract

Fracture dislocation of the carpometacarpal joints on the ulnar side of the hand is an uncommon injury. These are high-energy injuries seen in motorcyclists and boxers. The mechanism of injury involves violent, forceful dorsiflexion of the wrist combined with longitudinal impact on the closed hand. This article reports a case of fracture of the base of the middle finger with dislocation of the ring and little finger carpometacarpal joints. On first examination, a diagnosis of isolated, minimally-displaced, middle-metacarpal base fracture was made and deemed suitable for nonoperative management. The hand was splinted in a plaster-of-Paris slab. Later, a true lateral radiograph was obtained, which showed the exact nature of the injury. The fracture was successfully treated with closed reduction under general anesthesia and transfixation using Kirschner wires. Functional results were excellent with return to work at 10 weeks and excellent grip strength at 14 weeks. This injury may be missed in an acute setting in a busy accident and emergency unit. Swelling around the wrist with shortening of the knuckle should alert the clinician towards the possibility of such an injury. On routine anteroposterior view, overlap of joint surfaces, loss of parallelism, and asymmetry at the carpometacarpal joints should make one suspect the possibility of a subtle carpometacarpal injury. This article highlights the importance of a high index of suspicion, a true lateral radiograph, and careful evaluation of radiographs in diagnosing these injuries. Intensive postoperative physiotherapy is vital to achieving a satisfactory outcome.

Fracture dislocation of carpometacarpal joints on the ulnar side of the hand is an uncommon injury.1 Diagnosis of this unusual form of injury requires a high index of suspicion, careful clinical examination, and good radiographs.2 They are high-energy injuries seen in motorcyclists and boxers with a mechanism that involves violent, forceful palmarflexion of the wrist combined with longitudinal impact on the closed hand.3 Dislocation may be in a palmar or dorsal direction, and associated fractures of adjacent metacarpal or carpal bones may present.4

Carpometacarpal injuries account for <1% of hand injuries and may be overlooked or missed.5 Disability of the hand is severe when untreated or in those who received delayed treatment.6 The carpometacarpal joints of the hand are arthrodial diarthroses (gliding joints). The bases of the metacarpals articulate with the distal row of the carpal bones and with each other in an interlocking mechanism. Intermetacarpal and carpometacarpal ligaments, as well as ligaments of the wrist flexors and extensors that insert into the bases of the second, third, and fifth metacarpals, further reinforce the joints.5

Case Report

A 26-year-old man presented with right wrist pain after a fall on his outstretched hand. On examination, marked swelling of the wrist with significant bruising over the dorsum of the wrist and hand were found. He was globally tender around the wrist and over the metacarpals. He was unable to move his fingers actively due to pain, but he had good sensation and vascularity in his fingers.

Radiographs of the hand (Figures 1, 2) showed a minimally displaced middle metacarpal base fracture. The fracture was deemed suitable for nonoperative management. The hand was splinted in a plaster-of-Paris back slab.

On second examination, the patient was clinically and radiologically reassessed. The hand was still swollen and diffusely tender over the dorsum. Review of the initial radiographs showed loss of parallelism and symmetry at the carpometacarpal joints of the ring and little fingers with overlap of joint surfaces. Due to clinical suspicion, a true lateral radiograph was obtained. This revealed a dorsoulnar dislocation of the ring and little finger carpometacarpal joints along with a fracture of the third metacarpal base (Figure 3).

Figures 1 and 2
Figure 1: Posteroanterior radiograph of the hand showing loss of parallelism and symmetry at carpometacarpal joints of the ring and little fingers with joint surfaces overlap. Figure 2: Oblique radiograph of the hand showing a fracture of the base of the third metacarpal.
Figures 3 and 4
Figure 3: Lateral radiograph of the hand showing dislocated metacarpal bases. Figure 4: Postoperative posteroanterior radiograph of the hand showing restoration of parallelism and symmetry of the ring and little finger carpometacarpal joints with Kirschner wires in-situ.

Under general anesthetic, a closed manipulation was performed with image intensifier guidance. The fracture dislocation slipped into place on longitudinal traction and local pressure. However, the position was unstable and required stabilization with percutaneous Kirschner wires inserted from the shaft of the ring and little finger metacarpal into the hamate (Figures 4, 5). A below-elbow ulnar gutter slab was applied. The hand was elevated in a bedside sling and active finger movements were encouraged early on. Postoperative recovery was uneventful. The wires were removed at 4 weeks and gentle mobilization was commenced with the help of a hand therapist. At 10 weeks postoperatively, the patient had regained full function of his hand and was back to his work as a joiner (Figures 6, 7).

Figures 5, 6 and 7
Figure 5: Postoperative lateral radiograph of the hand showing restoration of carpometacarpal alignment with Kirschner wires in-situ. Figure 6: Posteroanterior radiograph of the hand at 10-week follow-up showing anatomical restoration. Figure 7: Lateral radiograph of the hand at 10-week follow-up showing anatomical restoration.

Discussion

Fracture dislocation of the carpometacarpal joints on the ulnar side of the hand is an uncommon injury.1 Fracture of the middle metacarpal with associated dislocation of the ring and little finger carpometacarpal joints is rare, with only 1 previously documented case in the literature.6 On that occasion, a true lateral view enabled the diagnosis to be made immediately and prompt treatment was initiated.

Carpometacarpal joint injuries on the ulnar side are caused by high-energy trauma. Stability at the carpometacarpal joints is provided by 4 ligaments. These are the metacarpal ligaments (dorsal and palmar) and the interosseous ligaments (dorsal and palmar). Unlike carpometacarpal joints on the ulnar side, the index metacarpal has a stable configuration through its wedge-shaped articulation with the trapezoid. A significant force is necessary to disrupt this joint.2

Due to gross swelling of the hand and metacarpal overlap on oblique radiographs, the true injury pattern is difficult to interpret and hence, the diagnosis of this injury may be missed or delayed. On routine anteroposterior (AP) view of joint surface overlap, loss of parallelism and asymmetry at the carpometacarpal joints should make one suspect the possibility of a subtle carpometacarpal injury. Identifying a fracture involving the base of a metacarpal should alert the clinician regarding the possibility of adjacent carpometacarpal joint injury. This should then warrant further clinical and radiological review. A true lateral view is required for diagnosis in those cases with a high index of suspicion. Closed reduction is successful in dislocations <10 days old.6 Injury to the ulnar nerve can occur due to its close proximity to the fifth carpometacarpal joint.6

Fracture of the base of the middle metacarpal with dislocation of the carpometacarpal joints of the ring and little finger is a rare injury. The true extent of this injury can be missed in an acute setting in a busy accident and emergency unit if true lateral radiographs are not taken. A high index of suspicion is required in diagnosing this unusual injury pattern. Swelling around the wrist with shortening of the knuckle should alert the clinician towards the possibility of such an injury. True posteroanterior and lateral radiographs are required to identify this injury. On routine AP view, overlap of joint surfaces, loss of parallelism, and asymmetry at the carpometacarpal joints should make one suspect the possibility of a subtle carpometacarpal injury. Closed reduction is successful if done quickly. Stabilization with percutaneous Kirschner wires is required. Intensive postoperative physiotherapy is vital to achieving a satisfactory outcome.

References

  1. Hsu JD, Curtis RM. Carpometacarpal dislocation on the ulnar side of the hand. J Bone Joint Surg Am. 1970; 52(5):927-928.
  2. Sharma AK, John TJ. Unusual case of carpometacarpal dislocation of all the four fingers of ulnar side of hand. Med J Armed Forces India. 2005; 61(2):188-189.
  3. Phelan MP. A case of carpometacarpal dislocation. J Emerg Med. 2006; 31(3):301-302.
  4. Hazlett JW. Carpometacarpal dislocations other than the thumb: a report of 11 cases. Can J Surg. 1968; 11:315-323.
  5. Henry M. Fractures and dislocations of the hand. In: Buchholz RW, Heckman JD, Green DP, eds. Rockwood and Green’s Fractures in Adults. Philadelphia, PA: Lippincott-Raven; 2001:369-374.
  6. Lawlis JF III, Gunther SF. Carpometacarpal dislocations. Long-term follow up. J Bone Joint Surg Am. 1991; 73(1):52-59.

Authors

Messrs Gaheer and Ferdinand are from the Department of Trauma and Orthopedics, Dumfries and Galloway Royal Infirmary, Dumfries, United Kingdom.

Messrs Gaheer and Ferdinand have no relevant financial relationships to disclose.

Correspondence should be addressed to: Rajinder Singh Gaheer, MS(Orth), MCh(Orth), FRCS(TR&Orth), Clinical Fellow, Department of Trauma and Orthopedics, Dumfries and Galloway Royal Infirmary, Bankend Road, Dumfries, United Kingdom, DG1 4AP (rsgaheer@hotmail.com).

doi: 10.3928/01477447-20110317-29

10.3928/01477447-20110317-29

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