Radial artery injury in association with fractures of the trapezium

RADIAL ARTERY INJURY IN ASSOCIATION WITH F R A C T U R E S OF THE T R A P E Z I U M A. J. C H E C R O U N , A. O. M E K H A I L and N. A. EBRAHEIM

From the Department of Orthopaedic Surgery, Medical College of Ohio, Toledo, Ohio, USA Three cases of trapezial fractures in which the radial artery was injured are reported. The injuries occurred during the initial trauma in one, when internal fixation was done in the second, and during hardware removal in the third. Six cadaveric wrists were dissected to study the relationship between the course of the artery and the trapezium. 'r

Journal of Hand Surgery (British and European Volume, 1997) 22B." 3:419-422 Trapezial fractures are rare, representing only 5% of all carpal injuries (Cordrey and Ferrer-Torells, 1960). Since the course of the radial artery can be distorted by a fracture of the trapezium, identification and protection of this blood vessel is recommended when operating in this region. CASE REPORTS Case 1

A 33-year-old man was injured when the go-cart in which he was riding flipped. He sought treatment 3 weeks after the accident because of persistent pain in the right hand. On examination, mild pain and tenderness at the base of the first metacarpal were noted. Pinching accentuated the pain. Posteroanterior, lateral, and 20 ° pronation X-rays revealed a trapezial fracture. Further evaluation with tomography and CT scans showed a significantly displaced comminuted fracture of the trapezium and a non-displaced coronal fracture of the capitate. Open reduction and internal fixation was done through a longitudinal lateral incision over the first dorsal compartment of the wrist. The interval between the abductor pollicis longus and the extensor pollicis brevis was entered, and the radial artery overlying the trapezium was identified and protected. The trapezium had four main fragments, two dorsal and two palmar. The dorsal fragments were pinned to the corresponding palmar fragments, and the two fragments were pinned together. A Hoffman external fixator was applied to prevent collapse of the comminuted fracture, with one pin in the first metacarpal and one in the radius (Fig 1). A minimal stepoff of the trapezium at the trapeziometacarpal joint was noted under fluoroscopy during surgery. The step-off was acceptable considering the extensive comminution. After surgery, there was no neurovascular deficit. The external fixator was removed 4 weeks later, and a shortarm thumb spica cast was applied for another 2 weeks. Three months after surgery, the fracture had healed, and the patient had regained full function with some irritation from the wires. Four months after surgery, the K-wires were removed through the same incision. When the tourniquet was released at the end of the procedure, a nick in the radial artery overlying the trapezium was discovered and repaired. Postoperatively, there was no neurovascular deficit.

Case 2

A 32-year-old woman with a history of chronic alcohol abuse was an unrestrained front seat passenger in a motor vehicle accident. She sustained a pneumothorax and multiple lacerations including a laceration at the base of the right thumb. X-rays of the right hand were not obtained. She was discharged 4 days later following treatment of the pneumothorax. Five days later, she was seen because of persistent pain at the base of the right thumb. On examination, significant tenderness and crepitus were noted. The neurovascular status was intact. Posteroanterior, lateral and 20 ° pronation X-rays revealed a vertical trapezial fracture. Further tomographic and CT examinations confirmed an isolated trapeziat fracture (Fig 2a). Operation 2 weeks after the injury confirmed the radiographic findings. The radial portion of the trapezium was displaced proximally with the first metacarpal, and the ulnar portion was rotated palmarwards. Two clamps were used to obtain an anatomical reduction under fluoroscopic guidance. Two 2.0 mm screws were placed laterally to medially across the fracture site (Fig 2b). Following release of the tourniquet, significant bleeding occurred from a complete laceration of the radial artery. Five minutes after the ends of the radial

Fig 1

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PA view following pinning of the trapezial fracture and application of an external fixator.

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Fig 2

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(a) Reconstruction CT showing displacement of the first metacarpal proximally between the radial fragment of the trapezium (small arrow) and the ulnar fragment (bifid arrow). (b) Fluoroscopic view of the wrist after screw fLxation.

artery were tied off, good capillary refill to both the thumb and the index finger was observed. A radial gutter splint was applied to immobilize the carpometacarpal joint. Postoperatively, the thumb and index finger were numb along the distribution of the superficial radial nerve. After the stitches were removed, a short-arm thumb spica cast was applied. Three weeks postoperatively, the cast was removed and occupational therapy was started. Seven months after injury, the numbness had completely resolved, and the fracture had healed. However, she had persistent mild pain at the base of the thumb and lacked some opposition.

A 4 cm transverse laceration proximal to the left palmar wrist crease was extended 2 cm distally on the radial side and 4 cm proximally on the ulnar side. Inspection of the wound revealed that the radial artery and vein were divided. After checking the circulation, the injured vessels were ligated. The wrist was reduced, the styloid fracture was fixed with K-wires and a Hoffman external fixator was applied. The trapezial fracture was reduced and fixed internally with K-wires. Postoperatively, the neurovascular status was normal. The K-wires were removed 6 weeks later. ANATOMICAL DISSECTION

Case 3

A 46-year-old woman sustained multiple injuries in a motor vehicle accident. Initial evaluation revealed an open fracture-dislocation of the left wrist. X-rays showed a vertical trapezial fracture, a radial styloid fracture, and dorsal wrist dislocation (Fig 3). After initial stabilization, internal fixation of the wrist was performed.

Six cadaveric wrists were dissected to study the course of the radial artery and its relationship to the trapezium. As it leaves the forearm, the radial artery winds dorsally around the lateral side of the carpus between the radial collateral ligament and the tendons of the abductor pollicis longus and extensor pollicis brevis and descends on the scaphoid and trapezium. Before disappearing between the heads of the first dorsal interosseous muscle,

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RADIALARTERYINJURYIN TRAPEZIALFRACTURES

Fig 3

Lateral view of the left wrist showing an open fracture-dislocation resultingin divisionof the radial artery and vein.

the radial artery is crossed by the extensor pollicis longus tendon. The radial artery courses through the groove between the easily palpable dorsoradial and the dorsoulnar tubercles of the trapezium. In the interval between the two extensor pollicis tendons (the anatomical "snuff box"), the artery is close to the digital branches of the superficial branch of the radial nerve that extend to the thumb and index finger (Fig 4). During its course in the hand, the radial artery anastomoses with the deep palmar branch of the ulnar artery to form the deep palmar arch. In the groove between the dorsoradial and the dorsoulnar tubercles of the trapezium, the radial artery gives several branches to the trapezium (Panagis et al, 1983; Zancolli and Cozzi, 1992). During its course on the trapezium, the radial artery gives the dorsal carpal branch and the second dorsal metacarpal artery (Gelberman et al, 1983; Zancolli and Cozzi, 1992)

proximal radial subluxation of the dorsal trapezial fragment with the attached first metacarpal (Connoly, 1981). The vertical fracture lies in a weak zone in the sagittal plane between two vertical trabecular condensations (Pointu et al, 1988). Jones and Ghorbal (1985) reported three cases of trapezial fractures in which a similar injury pattern was identified on the X-rays. The fracture line extended from the articular surface of the trapezium within the trapeziometacarpal joint into the dorsal and lateral surface of the bone, usually without significantly entering the trapezioscaphoid joint, separating a fragment from the dorsolateral corner of the bone with variable comminution. This fragment displaced dorsally and proximally, and the first metacarpal subluxated with it. As demonstrated in our report, the diagnosis of a trapezial fracture is often delayed. Point tenderness and a high index of suspicion are keys to making a diagnosis since patients are often surprisingly comfortable. In some cases, a painful, weak pinch is the patient's only complaint (Botte and Gelberman, 1987; Cordrey and FerrerTorells, 1960; Griffin et al, 1988; Jones and Pellegrini, 1989). Special X-ray projections can identify trapezial body fractures. The most satisfactory projection is an oblique view, made with the ulnar border of the hand resting on the cassette with the forearm in 20 ° of pronation. The entire horizontal diameter o f the trapezium with its articulation with the second metacarpal and the trapezoid are visualized (Cordrey and Ferrer-Torells, 1960). The anatomical distortion caused by the fracture or

DISCUSSION Pointu et al (1988) classified trapezial fractures into four groups - vertical, horizontal, oblique and comminuted and described vertical fractures in 61 of the 88 cases that they reviewed. Botte and Gelberman (1987) stated that fractures o f the trapezial body have either a vertical or comminuted configuration, the latter being more common. In the study reported by Cordrey and FerrerTorells (1960), isolated vertical fractures accounted for about 20% of all trapezial fractures. Vertical trapezial fractures typically result from cleavage through the midsagittal axis of the bone and often are accompanied by a

Fig 4

Photograph of the snuff box area of the wrist. The radial artery coursesover the trapeziumbetweenthe dorsoradial and dorsoulnar tubercles. The joint around the trapezium is open to show the outline of the trapezium. The radial artery passes beneath the retracted extensor poUicis longus tendon (E) to enter the space between the two heads of the first dorsal interosseous muscle. The extensor pollicis longus tendon covers the joint between the trapezium and second metacarpal. The dorsal carpal branch of the radial artery coursesalong the scaphotrapezialjoint (bifid arrow). Straight arrow = trapeziotrapezoid joint; small arrowhead = joint between trapezium and first metacarpal; large arrowhead = extensorpollicis brevis tendon.

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scarring may increase the risk of radial artery injury during early or delayed surgical treatment of trapezial fractures. Since the radial artery is in line with a vertical trapezial fracture, the surgeon should be aware of the possibility of the artery being caught between the two fracture fragments. Pointu et al (1988) recommended operating without a tourniquet to facilitate identification of the radial artery. The radial artery should be repaired whenever possible. This can be done with standard microvascular techniques using 9/0 interrupted nylon sutures. Since the trapezium has an ample vascular supply, the risk of avascular necrosis is low (Gelberman and Gross, 1986). In the three cases described in this report, the fractures healed without any evidence of avascular necrosis or subsequent vascular impairment. The anatomical reduction of intraarticular fractures is recommended to prevent arthritis in the trapeziometacarpal joint (Botte and Gelberman, 1987; Cordrey and Ferrer-Torells, 1960). Cordrey and FerrerTorells (1960) were the first to recommend open reduction and Kirschner wire fixation of vertically displaced intraarticular trapezial fractures. In their technique, a 5 cm horizontal incision is made at the base of the thumb, and deep dissection is performed between the extensor pollicis brevis and the abductor pollicis longus, which are retracted palmarward, and the extensor pollicis longus, which is retracted ulnarward. Cordrey and Ferrer-Torells noted that the sensory branch of the radial nerve to the thumb courses lateral to the first carpometacarpal joint and thus should be retracted ulnarward along with the radial artery. The capsule of the carpometacarpal joint is opened through a transverse incision. Foster and Hastings (1987) used a 2.5 cm transverse incision over the radial aspect of the wrist at the base of the thumb metacarpal to repair isolated verticallyoriented intraarticular trapezial fractures. In their technique, either the extensor pollicis brevis and abductor pollicis longus are retracted palmarly together or the dissection is carried out between the two. The radial artery is protected and retracted ulnarly. Kirschner wires are used for fixation. Jones and Pellegrini (1989) used a lateral approach to manage a horizontal trapezial fracture with open reduction and internal fixation. Freeland and Finley (1984) obtained an excellent result using a small cancellous lag screw to fix a displaced vertical trapezial fracture through a lateral approach. Pointu et al (1988) used either a transverse or longitudinal lateral incision for open reduction and internal fixation of trapezial fractures. Harvey-Gervis (1949) described the use of an incision parallel to the extensor pollicis brevis in the distal part of the anatomical snuff box to excise the trapezium in a patient with osteoarthritis of the trapeziometacarpal joint. They recommended protecting the distal portion of the radial artery where it crosses the trapezium on its

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way to the deep palmar arch. An elevator can be used in the scaphotrapezial joint while the articulations with the trapezoid and the second metacarpal bones are defined. They emphasized the importance of staying close to the bone while working on the palmar surface to avoid damaging the flexor carpi radialis tendon in its groove in the trapezium. Garcia-Elias et al (1993) used a palmar approach for open reduction and fixation of fractures of the trapezium combined with a Bennett's fracture. The surgeon should be aware of the potential for distortion of the course of the radial artery in either early or late presentations of trapezial fractures. The radial artery should be identified and isolated where it lies on the trapezium before treating the fracture. Acknowledgement The authors thank Dr W. T. Jackson for his contribution to the study.

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