Fracture-dislocations of the carpus represent a spectrum of complex injuries1-3,5-12,14. Accurate description of a specific injury may be difficult because of the number of skeletal and ligamentous structures involved. Some authors have suggested that these injuries represent so-called perilunate injuries, as the mechanism of injury has been noted to follow a pattern about the lunate5,9,10. Moneim described greater arc injuries as those including trans-scaphoid, transcapitate, trans-hamate, and transtriquetral perilunate fracture-dislocations. When the lunate itself is dislocated, the injury is more extensive and classification is more difficult.
We report the case of a patient who had an unusual fracture-dislocation of the wrist. The lunate was displaced volarly in conjunction with displaced fractures of the adjacent scaphoid and triquetrum.
*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.
†Los Angeles County and University of Southern California School of Medicine, 2025 Zonal Avenue, GNH 3900, Los Angeles, California 90033.
Fig. 1-A Posteroanterior, oblique, and lateral radiographs showing the trans-scaphoid, transtriquetral, volar lunate fracture-dislocation.
Fig. 1-B Posteroanterior, oblique, and lateral radiographs showing the trans-scaphoid, transtriquetral, volar lunate fracture-dislocation.
Fig. 1-C Posteroanterior, oblique, and lateral radiographs showing the trans-scaphoid, transtriquetral, volar lunate fracture-dislocation.
Fig. 2-A Line drawings representing the initial posteroanterior and lateral radiographs. S = proximal scaphoid fragment, L = lunate, and T = proximal triquetral fragment.
Fig. 2-B Line drawings representing the initial posteroanterior and lateral radiographs. S = proximal scaphoid fragment, L = lunate, and T = proximal triquetral fragment.
Fig. 3-A Posteroanterior and lateral radiographs, made intraoperatively, showing Kirschner wires stabilizing the scaphoid fracture and two additional Kirschner wires stabilizing the reduction of the carpus.
Fig. 3-B Posteroanterior and lateral radiographs, made intraoperatively, showing Kirschner wires stabilizing the scaphoid fracture and two additional Kirschner wires stabilizing the reduction of the carpus.
Fig. 4 Posteroanterior radiograph, made six months postoperatively, showing complete healing and increased radiodensity in the proximal portion of the scaphoid and in the lunate.
Fig. 5 Posteroanterior radiograph, made eight years after the injury, showing changes consistent with radiocarpal osteoarthrosis and sclerosis of the proximal pole of the scaphoid.
A twenty-six-year-old, female, right-hand-dominant law student fell from a height of approximately twenty-four feet (7.3 meters). She could not recall the position of the upper extremity at the time of the impact. On examination, the right wrist was markedly swollen and any attempt at motion produced pain. Sensibility was diminished in the distribution of the median nerve and, although deep-pressure sensation was present, light-touch sensation was absent. Circulation to the hand was intact. The only associated injury was a compression fracture of the second lumbar vertebra without neurological deficit. Radiographs of the right wrist showed displaced fractures of the scaphoid and triquetrum as well as volar dislocation of the lunate (Figs. 1-A, 1-B, 1-C, 2-A through 2-B).
Open reduction and internal fixation was performed with the use of axillary block anesthesia. The transverse retinacular ligament as well as the fascia over the anterior compartments of the forearm were released through a volar approach. A dorsal incision was necessary to facilitate the realignment of the carpal bones. The operative findings included a complete rupture of the scapholunate ligament and an intact lunotriquetral ligament with an attached fragment of triquetrum. The articular surfaces of the carpal bones were not damaged, although the bones of the proximal row were devoid of soft-tissue attachments.
It was decided to proceed with operative realignment and internal fixation rather than proximal-row carpectomy. The scaphoid fracture was reduced and was stabilized with two 0.045-inch (0.114-centimeter) Kirschner wires. Two additional such wires were used because of the difficulty encountered in maintaining the reduction of the carpus (Figs. 3-A and 3-B). The fixation of the triquetral fracture with Kirschner wires was unsuccessful because of comminution; however, with reduction of the lunate and the scaphoid, the large displaced fragment of the triquetrum was restored to its site of detachment. The torn volar and dorsal intracapsular ligaments were repaired.
Postoperatively, the patient wore an above-the-elbow splint for ten days and then wore a below-the-elbow thumb-spica plaster cast. The immobilization was continued for sixteen weeks, at which time the Kirschner wires were removed. Radiographs made at that time showed that the fractures had united; however, there was an increase in the radiodensity of the proximal portion of the scaphoid and the lunate. The function of the median nerve had returned to normal.
Six months after the operation, the patient was pain-free. She lacked 30 degrees of flexion and 25 degrees of extension of the wrist compared with the values for the contralateral wrist. Pronation and supination of the forearm were equal bilaterally. Radiographs continued to suggest increased radiodensity in the proximal portion of the scaphoid and the lunate (Fig. 4).
Eight years after the original injury, the patient was able to work full-time as an attorney, to perform all activities of daily living, and to enjoy recreational swimming. She noted only minimum discomfort, after typing for forty minutes. She had normal pronation and supination of the forearm. Radial and ulnar deviation of the involved wrist were 8 and 14 degrees, respectively, compared with 15 and 20 degrees for the uninvolved wrist. She lacked 25 degrees of volar flexion and 20 degrees of extension of the wrist compared with the values for the contralateral wrist. Grip strength, as measured with the Jamar dynamometer (J. A. Preston, Jackson, Michigan), was seventy pounds (31.8 kilograms) on the right side compared with ninety pounds (40.8 kilograms) on the left. Radiographs showed radiocarpal osteoarthrosis and continued sclerosis of the proximal pole of the scaphoid (Fig. 5).
A number of classification systems have been developed to describe the patterns of fracture-dislocation of the wrist; however, the constellation of soft-tissue and skeletal injuries makes categorization of these injuries difficult.
The term perilunate dislocation should be reserved for injuries in which the lunate remains in its normal relationship to the radius, with dislocation of the surrounding carpal bones. Weseley and Barenfeld described a trans-scaphoid, transcapitate, transtriquetral perilunate fracture-dislocation of the wrist, which was treated with open reduction and bone-grafting without internal fixation. At the two-year follow-up evaluation, their patient was asymptomatic and the range of motion of the wrist was almost equal bilaterally, but radiographs showed degenerative changes. Campbell et al.2 reported on a patient who had a trans-scaphoid dorsal perilunate dislocation with an associated transtriquetral fracture. The lunate remained in its anatomical association with the radius. Gellman et al. reported the case of a patient that was similar to that of our patient; however, they described the injury as a perilunate fracture-dislocation. Our patient had greater displacement of the osseous structures. On the basis of the radiographs in the study by Gellman et al. as well as the injury described in the current study, we believe that these injuries are best described as trans-scaphoid, transtriquetral, volar lunate fracture-dislocations, as the lunate is completely dislocated.
The severity of the ligamentous and osseous injuries in many fracture-dislocations of the wrist has led some investigators to recommend treatment with open reduction and internal fixation4,12,15. In our patient, the bone fragments (with the exception of those of the triquetrum) were large enough to allow anatomical reduction, and despite the severity of the loss of soft-tissue attachments of these fragments it was thought that reduction and stabilization with Kirschner wires would be better than immediate proximal-row carpectomy.
While the functional recovery of our patient was satisfactory, it must be pointed out that radiographic changes consistent with avascular necrosis of the scaphoid and the lunate as well as with early changes of radiocarpal osteoarthrosis were noted at the eight-year follow-up evaluation. Similarly, Palmer et al. found that these radiographic findings may not be related to the clinical symptoms.
In summary, we propose the term trans-scaphoid, transtriquetral, volar lunate fracture-dislocation to describe this particular injury. In the absence of articular damage, we recommend open reduction and internal fixation, with repair of the ligaments if possible, to optimize the functional result.