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Trans-Triquetral Dorsal Perilunate Fracture DislocationFrom the Orthopaedics and Traumatology Department, Yan Chai Hospital, Tsuen Wan, China and the Orthopaedics and Traumatology Department, Queen Mary Hospital, Pokfulam, Hong Kong, China Correspondence: Dr. Yuen-Fai Leung, Orthopaedics and Trauma department, Rm 369, Block B, Yan Chai Hospital, Tsuen Wan, NT, Hong Kong, China. Tel.: +86 852 24178383; fax: +86 852 24116536 E-mail:drleungyf{at}gmail.com
A rare case of trans-triquetral dorsal perilunate dislocation is described. It differs from the Mayfield and Johnson theory of progressive perilunar instability in greater arc injuries which states that the injury passes from the radial to the ulnar carpal bones and soft tissues in stages. This injury supports the concept of a reverse greater arc injury from ulnar to radial being possible with the radial carpal bones being spared in some cases.
Key Words: perilunate dislocation • trans-triquetral According to Mayfield and Johnson’s classification of greater arc fracture dislocations of perilunate carpal injuries, the injury starts from the radial carpal bones and soft tissues and then extends to the ulnar side of the carpus with increasing magnitude of injury (Johnson, 1980; Mayfield et al., 1980). Stage III complete arc injury is the end-point of major trauma of the carpal bones and soft tissues around the lunate along the scaphoid–capitate–hamate–triquetrum ring. We report a patient who sustained a wrist injury resulting in trans-triquetral perilunate dislocation with sparing of the scaphoid, capitate and hamate bones. The surgical treatment and clinical outcome are discussed.
A 30 year-old right-handed man sustained an acute right wrist injury in a traffic accident in 1997. As he lost consciousness after the accident and had retrograde amnesia, the exact mechanism of wrist injury could not be recalled. The X-rays showed a trans-triquetral dorsal perilunate fracture dislocation associated with avulsion fracture of the radial and ulnar styloids (Fig 1). Volar intercalated segmental instability (VISI) was noted. Open reduction and internal fixation of the wrist with multiple K-wires (Fig 2) was performed under general anaesthesia. A dorsal approach was performed 2 days later and a transverse fracture of the triquetral body without comminution was confirmed. The scapholunate ligament and the lunato-triquetral ligaments were preserved. Laxity, or mild lengthening, of these ligaments was noticed, but they were in continuity. The radio–scapholunate ligament was intact. Since there were associated avulsion fractures of the ulnar styloid and radial styloid, we also transfixed the scaphoid lunate interval with two K-wires. As the wrist and distal radioulnar joint were then very stable, we did not attempt to fix the two styloid processes. A short arm cast was applied for 6 weeks and followed by a functional short arm plastic brace for a further 4 weeks. The K-wires were removed 8 weeks after the operation. His recovery was uneventful after a course of physiotherapy.
At four-year follow-up, wrist motion was satisfactory with 60° of palmar flexion, 70° of dorsiflexion, full supination and pronation, but with a mild decrease in radial and ulnar deviation. The uninjured wrist could achieve 70° of palmar flexion and 85° of dorsiflexion. The grip strength of his right hand was 20 kgf while that of the uninjured (non-dominant) side was 23 kgf. He had returned to all of his previous activities. The functional outcome was fair, with a Mayo wrist score of 75/100. No avascular necrosis of the triquetrum was detected. The radial styloid fracture healed and he had an asymptomatic ulnar styloid non-union. No degenerative changes of the radio-carpal and mid-carpal joints were present on X-ray (Fig 3).
The mechanism of the greater arc injury is hyperextension, ulnar deviation and intercarpal supination of the wrist. The dorsal radial lip of the distal radius impinges on the waist of the scaphoid resulting in trans-scaphoid perilunate dislocation (Stage I). It further impacts on the body of the capitate and causes a trans-scaphoid, trans-capitate perilunate dislocation (Stage II) (Pandit, 1998; Kaulesar Sukul and Johannes, 1992; Resnik et al., 1983). With further progression of the injury, the triquetrum fractures and a complete greater arc injury of trans-scaphoid, trans-capitate, trans-triquetral perilunate dislocation occurs (Stage III) (Leung et al., 2006; Weseley and Barenfeld, 1972). According to Mayfield and Johnson’s theory of perilunate instability, the greater arc injury progresses from Stages I to Stage III with increasing magnitude of the trauma, with the effect of the injury starting radially and extending ulnarly in stages (Mayfield et al., 1980). Our literature search suggests that an isolated trans-triquetral perilunate dislocation, i.e. an isolated ulnar carpal injury, with intact radial carpal bones has never been reported in the English literature. The injury described above would suggest that a greater arc injury can start ulnarly and progress radially. Skelly et al. (1991) suggested that such a reverse greater arc injury may occur but there has been no previous clinical data to support their theory. Their case report was a combined greater and lesser arc injury, with volar dislocation of the lunate and a triquetral shearing fracture.
Manuscript received August 8, 2006. Accepted for publication May 23, 2007.
Johnson RP (1980). The acutely injured wrist and its residuals. Clinical Orthopedics and Related Research, 149: 33–44.Kaulesar Sukul DM, Johannes EJ (1992). Transscapho–transcapitate fracture dislocation of the carpus. Journal of Hand Surgery, 17A: 348–353.[CrossRef][Medline] [Order article via Infotrieve]Leung YF, Ip, Shirley PS, Wong A, Ip WY (2006). Trans-scaphoid trans-capitate trans-triquetral perilunate fracture dislocation—a case report. Journal of Hand Surgery, 31A: 608–610.[CrossRef][Medline] [Order article via Infotrieve]Mayfield JK, Johnson RP, Kilcoyne RK (1980). Carpal dislocations: pathomechanics and progressive perilunar instability. Journal of Hand Surgery, 5A: 226–241.[Medline] [Order article via Infotrieve]Pandit R (1998). Proximal and palmar dislocation of the lunate and proximal scaphoid as a unit in a case of scaphocapitate syndrome. A 32-month follow-up. Journal of Hand Surgery, 23B: 266–268.[CrossRef][Medline] [Order article via Infotrieve]Resnik CS, Gelberman RH, Resnick D (1983). Transscaphoid, transcapitate, perilunate fracture dislocation (scaphocapitate syndrome). Skeletal Radiology, 9: 192–194.[CrossRef][Web of Science][Medline] [Order article via Infotrieve]Skelly WJ, Nahigian SH, Hidvegi EB (1991). Palmar lunate transtriquetral fracture dislocation. Journal of Hand Surgery, 16A: 536–539.[CrossRef][Medline] [Order article via Infotrieve]Weseley MS, Barenfeld PA (1972). Trans-scaphoid, transcapitate, transtriquetral, perilunate fracture-dislocation of the wrist. A case report. Journal of Bone Joint Surgery, 54A: 1073–1078.
Journal of Hand Surgery (European Volume), Vol. 32, No. 6,
647-648 (2007)
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Abstract
CASE REPORT
