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Fracture and dislocation about the carpal lunate
CASE REPORT
Fracture and Dislocation About the Carpal Lunate James R. Ryan, MD Detroit, Michigan
A case of delayed diagnosis of dislocation of the carpal lunate is presented emphasizing the difficulty in diagnosing injuries about the carpal lunate. The types of fractures and dislocations about the carpal lunate are described, along with the clinical and radiographic findings that are helpful in making the diagnosis. Ryan JR: Fracture and dislocation about the carpal lunate. Ann
Emerg Med 9:158-160, March 1980. injury, wrist, dislocation; injury, wrist, fracture INTRODUCTION F r a c t u r e s and dislocations about the carpal l u n a t e are uncommon. 1 Because of the low incidence, and because the radiographs are difficult to interpret, the i n j u r y is commonly overlooked a n d treated as a sprain2, 2 Such a result m a y lead to crippling arthritis of the wrist j o i n t with m a r k e d disability. 1 A case of a mixed diagnosis of carpal l u n a t e dislocation is presented to illustrate the need for close s c r u t i n y of radiographs for injuries about the wrist.
CASE REPORT A 23-year-old m a n was seen i n the office with a history of h a v i n g injured his right wrist three m o n t h s previously. At the time of i n j u r y he was seen i n the emergency d e p a r t m e n t where radiographs were interpreted as n o r m a l by the emergency physician and radiologist. The p a t i e n t was a g y m n a s t for a u n i v e r s i t y athletic team and was u n a b l e to participate because of loss of motion and continued pain in the wrist. Physical e x a m i n a t i o n revealed a n o r m a l young m a n except for the right wrist, which was diffusely swollen. There was tenderness to palpation, especially over the volar aspect of the wrist, where there was thickening. There was loss of range of metion i n all planes of the wrist joint. Radiographs obtained i n the office revealed a volar dislocation of the carpal lunate. The radiographs were obtained from the hospital where the p a t i e n t was originally seen, and confirmed a dislocation at t h a t time. Because the p a t i e n t was y o u n g and a gymnast, it was felt t h a t open reduction rather t h a n excision of the carpal lunate, which is generally recommended for an old dislocation, 3 be attempted. C o n s e q u e n t l y a n open reduction was und e r t a k e n and the bone was fixated with two K i r s c h n e r wires and held in place for six weeks. A t the end of this period the wires were removed and he was started on a range of motion exercise program. F o r t u n a t e l y the bone did not undergo avascular necrosis. The p a t i e n t regained almost normal motion and was able to resume n o r m a l activities. From the Department of Orthopedic Surgery, Wayne State University School of Medicine, Detroit, Michigan. Address for reprints: James R. Ryan, MD, Department of Orthopedic Surgery, Wayne State University School of Medicine, 540 East Canfield Avenue, Detroit, Michigan 48201.
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Ann Emerg Meal
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DISCUSSION The l u n a t e m a y dislocate in relation to the radius and other carpal bones. The dislocation is u s u a l l y in a volar direction (Figure 1). The l u n a t e m a y r e t a i n its n o r m a l relation with the radius even when the other carpal bones dislocate. This i n j u r y is called a p e r i l u n a t e dislocation (Figu r e 2). I n t h i s i n j u r y , t h e c a r p a l bones usually dislocate dorsally. F r e q u e n t l y in a p e r i l u n a t e dislocation the carpal n a v i c u l a r or scaphoid is also fractured. This i n j u r y is called a t r a n s n a v i c u l a r p e r i l u n a t e dislocation, 4 and u s u a l l y results from a fall on the extended wrist. The clinical findings with l u n a t e dislocation are swelling a n d localized t e n d e r n e s s over the volar aspect of the wrist. The fingers are u s u a l l y held in slight flexion. Flexion of the wrist is painful and limited. Because of the volar displacement of the lun a t e , t h e r e m a y be m e d i a n n e r v e symptoms. 3 The clinical findings in p e r i l u n a t e dislocations and t r a n s n a v i c u l a r p e r i l u n a t e dislocations are often s i m i l a r to those of the displaced Colles' fracture. As might be expected, t h e r e is swelling a n d localized t e n d e r n e s s in the area. With l u n a t e dislocations, the anteroposterior radiograph i l l u s t r a t e s the l u n a t e absent from its normal location with a large gap in this region. If the l u n a t e rotates 90 degrees, it is seen as a tria n g u l a r s h a p e r a t h e r t h a n as its n o r m a l quadrilateral shape. On the l a t e r a l r a d i o g r a p h , the l u n a t e appears displaced volarward and usually rotated. A search for the head of the capitate reveals t h a t it does not articulate as it should with the carpal lunate. When one sees a fracture of the n a v i c u l a r , a n associated p e r i l u n a t e d i s l o c a t i o n s h o u l d be c o n s i d e r e d . W i t h o u t a f r a c t u r e d n a v i c u l a r the dislocation, if p r e s e n t , m a y be difficult to i n t e r p r e t in the AP radiograph. The best view is the lateral radiograph, which reveals a l u n a t e normally articulating with the radius. However the capitate is displaced dorsally and the head of the capitate does not articulate with the lunate. There may be related disassociation between the carpal l u n a t e and n a v i c u l a r with these injuries.5, 6 It is i m p o r t a n t to note t h a t this i n j u r y u s u a l l y requires surgical reduction. A n a b n o r m a l gap between the carpal n a v i c u l a r and l u n a t e is seen on the AP radiograph, where the space should bear the same relat i o n s h i p as the space b e t w e e n the other carpal a r t i c u l a t i o n s 2
9:3 (March) 1980
Fig. 1. A. Lateral radiograph of a lunate dislocation. Note that lunate bone has
rotated 90 degrees and is volarward to the radius and capitate. B. AP radiograph of a lunate dislocation. Because of the 90 degree rotation, the lunate is triangular rather than quadrilateral, seen in Figure 2C. C. AP and lateral drawings corresponding with radiographs.
Ann Emerg Med
/159/67
CONCLUSION Fractures and dislocations about the carpal l u n a t e are serious injuries which require prompt attention. Pat i e n t s with injuries about the wrist should not be diagnosed as h a v i n g s p r a i n s a n d r e l e a s e d from t h e e m e r g e n c y d e p a r t m e n t u n t i l the physician is confident in i n t e r p r e t i n g the radiographs of these injuries.
REFERENCES 1. Morawa LG, Ross PM, Schock CC: Fractures and dislocations involving the navicular-lunate axis. Clin Orthop 118: 48-53, 1976. 2. Campbell RD, Lance EM, Yeoh LB: Lunate and perilunar dislocations. J Bone Joint Surg 46B:55-72, 1964. 3. Watson-Jones R: Carpal semilunar dislocations and other wrist dislocations with associated nerve lesions. Problems and Solutions in Medicine 22:11071, 1929. 4. Thompson TL, Campbell RD, Arnold WD: Primary and secondary dislocations of the scaphoid bone. J Bone Joint Surg 46B:73-82, 1964. 5. Linscheid RL, Dobyns JH, Beabout JW, et al: Traumatic instability of the wrist. J Bone Joint Surg 54:1612-1632, 1972. 6. Crenshaw AH (ed): Campbell's Operative Orthopedics. St. Louis, CV Mosby, 1971, pp 431, 447. I f
.
2C
Fig. 2. A. Lateral radiograph of a transnavicular perilunate dislocation. Note that lunate articulates normally with the radius and the capitate is displaced dorsally in relation to the lunate. B. AP radiograph of a transnavicular perilunate dislocation. Note the normal quadrilateral shape of the lunate. A fracture can be seen through the carpal navicular and the capitate overlaps the lunate. C. AP and lateral drawings corresponding with radiographs.
68/160
Ann Emerg Med
9.3 (M arc h) 198O
Fracture and Dislocation About the Carpal Lunate James R. Ryan, MD Detroit, Michigan
A case of delayed diagnosis of dislocation of the carpal lunate is presented emphasizing the difficulty in diagnosing injuries about the carpal lunate. The types of fractures and dislocations about the carpal lunate are described, along with the clinical and radiographic findings that are helpful in making the diagnosis. Ryan JR: Fracture and dislocation about the carpal lunate. Ann
Emerg Med 9:158-160, March 1980. injury, wrist, dislocation; injury, wrist, fracture INTRODUCTION F r a c t u r e s and dislocations about the carpal l u n a t e are uncommon. 1 Because of the low incidence, and because the radiographs are difficult to interpret, the i n j u r y is commonly overlooked a n d treated as a sprain2, 2 Such a result m a y lead to crippling arthritis of the wrist j o i n t with m a r k e d disability. 1 A case of a mixed diagnosis of carpal l u n a t e dislocation is presented to illustrate the need for close s c r u t i n y of radiographs for injuries about the wrist.
CASE REPORT A 23-year-old m a n was seen i n the office with a history of h a v i n g injured his right wrist three m o n t h s previously. At the time of i n j u r y he was seen i n the emergency d e p a r t m e n t where radiographs were interpreted as n o r m a l by the emergency physician and radiologist. The p a t i e n t was a g y m n a s t for a u n i v e r s i t y athletic team and was u n a b l e to participate because of loss of motion and continued pain in the wrist. Physical e x a m i n a t i o n revealed a n o r m a l young m a n except for the right wrist, which was diffusely swollen. There was tenderness to palpation, especially over the volar aspect of the wrist, where there was thickening. There was loss of range of metion i n all planes of the wrist joint. Radiographs obtained i n the office revealed a volar dislocation of the carpal lunate. The radiographs were obtained from the hospital where the p a t i e n t was originally seen, and confirmed a dislocation at t h a t time. Because the p a t i e n t was y o u n g and a gymnast, it was felt t h a t open reduction rather t h a n excision of the carpal lunate, which is generally recommended for an old dislocation, 3 be attempted. C o n s e q u e n t l y a n open reduction was und e r t a k e n and the bone was fixated with two K i r s c h n e r wires and held in place for six weeks. A t the end of this period the wires were removed and he was started on a range of motion exercise program. F o r t u n a t e l y the bone did not undergo avascular necrosis. The p a t i e n t regained almost normal motion and was able to resume n o r m a l activities. From the Department of Orthopedic Surgery, Wayne State University School of Medicine, Detroit, Michigan. Address for reprints: James R. Ryan, MD, Department of Orthopedic Surgery, Wayne State University School of Medicine, 540 East Canfield Avenue, Detroit, Michigan 48201.
66/158
Ann Emerg Meal
9:3 (March) 1980
DISCUSSION The l u n a t e m a y dislocate in relation to the radius and other carpal bones. The dislocation is u s u a l l y in a volar direction (Figure 1). The l u n a t e m a y r e t a i n its n o r m a l relation with the radius even when the other carpal bones dislocate. This i n j u r y is called a p e r i l u n a t e dislocation (Figu r e 2). I n t h i s i n j u r y , t h e c a r p a l bones usually dislocate dorsally. F r e q u e n t l y in a p e r i l u n a t e dislocation the carpal n a v i c u l a r or scaphoid is also fractured. This i n j u r y is called a t r a n s n a v i c u l a r p e r i l u n a t e dislocation, 4 and u s u a l l y results from a fall on the extended wrist. The clinical findings with l u n a t e dislocation are swelling a n d localized t e n d e r n e s s over the volar aspect of the wrist. The fingers are u s u a l l y held in slight flexion. Flexion of the wrist is painful and limited. Because of the volar displacement of the lun a t e , t h e r e m a y be m e d i a n n e r v e symptoms. 3 The clinical findings in p e r i l u n a t e dislocations and t r a n s n a v i c u l a r p e r i l u n a t e dislocations are often s i m i l a r to those of the displaced Colles' fracture. As might be expected, t h e r e is swelling a n d localized t e n d e r n e s s in the area. With l u n a t e dislocations, the anteroposterior radiograph i l l u s t r a t e s the l u n a t e absent from its normal location with a large gap in this region. If the l u n a t e rotates 90 degrees, it is seen as a tria n g u l a r s h a p e r a t h e r t h a n as its n o r m a l quadrilateral shape. On the l a t e r a l r a d i o g r a p h , the l u n a t e appears displaced volarward and usually rotated. A search for the head of the capitate reveals t h a t it does not articulate as it should with the carpal lunate. When one sees a fracture of the n a v i c u l a r , a n associated p e r i l u n a t e d i s l o c a t i o n s h o u l d be c o n s i d e r e d . W i t h o u t a f r a c t u r e d n a v i c u l a r the dislocation, if p r e s e n t , m a y be difficult to i n t e r p r e t in the AP radiograph. The best view is the lateral radiograph, which reveals a l u n a t e normally articulating with the radius. However the capitate is displaced dorsally and the head of the capitate does not articulate with the lunate. There may be related disassociation between the carpal l u n a t e and n a v i c u l a r with these injuries.5, 6 It is i m p o r t a n t to note t h a t this i n j u r y u s u a l l y requires surgical reduction. A n a b n o r m a l gap between the carpal n a v i c u l a r and l u n a t e is seen on the AP radiograph, where the space should bear the same relat i o n s h i p as the space b e t w e e n the other carpal a r t i c u l a t i o n s 2
9:3 (March) 1980
Fig. 1. A. Lateral radiograph of a lunate dislocation. Note that lunate bone has
rotated 90 degrees and is volarward to the radius and capitate. B. AP radiograph of a lunate dislocation. Because of the 90 degree rotation, the lunate is triangular rather than quadrilateral, seen in Figure 2C. C. AP and lateral drawings corresponding with radiographs.
Ann Emerg Med
/159/67
CONCLUSION Fractures and dislocations about the carpal l u n a t e are serious injuries which require prompt attention. Pat i e n t s with injuries about the wrist should not be diagnosed as h a v i n g s p r a i n s a n d r e l e a s e d from t h e e m e r g e n c y d e p a r t m e n t u n t i l the physician is confident in i n t e r p r e t i n g the radiographs of these injuries.
REFERENCES 1. Morawa LG, Ross PM, Schock CC: Fractures and dislocations involving the navicular-lunate axis. Clin Orthop 118: 48-53, 1976. 2. Campbell RD, Lance EM, Yeoh LB: Lunate and perilunar dislocations. J Bone Joint Surg 46B:55-72, 1964. 3. Watson-Jones R: Carpal semilunar dislocations and other wrist dislocations with associated nerve lesions. Problems and Solutions in Medicine 22:11071, 1929. 4. Thompson TL, Campbell RD, Arnold WD: Primary and secondary dislocations of the scaphoid bone. J Bone Joint Surg 46B:73-82, 1964. 5. Linscheid RL, Dobyns JH, Beabout JW, et al: Traumatic instability of the wrist. J Bone Joint Surg 54:1612-1632, 1972. 6. Crenshaw AH (ed): Campbell's Operative Orthopedics. St. Louis, CV Mosby, 1971, pp 431, 447. I f
.
2C
Fig. 2. A. Lateral radiograph of a transnavicular perilunate dislocation. Note that lunate articulates normally with the radius and the capitate is displaced dorsally in relation to the lunate. B. AP radiograph of a transnavicular perilunate dislocation. Note the normal quadrilateral shape of the lunate. A fracture can be seen through the carpal navicular and the capitate overlaps the lunate. C. AP and lateral drawings corresponding with radiographs.
68/160
Ann Emerg Med
9.3 (M arc h) 198O