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Traction radiography for the diagnosis of scapholunate ligament tears
ARTICLE IN PRESS TRACTION RADIOGRAPHY FOR THE DIAGNOSIS OF SCAPHOLUNATE LIGAMENT TEARS M. SCHA¨DEL-HO¨PFNER, G. BO¨HRINGER, L. GOTZEN and I. CELIK From the Department of Traumatology and Hand Surgery, University Hospital, Marburg, Germany, Department of Traumatology, University Hospital, GieX en, Germany and Institute of Theoretical Surgery, University Hospital, Marburg, Germany
The diagnosis of scapholunate ligament injury by traction radiography was investigated within a consecutive study. The right wrists of 25 healthy volunteers and 22 wrists with arthroscopically proven complete scapholunate ligament tears were examined. Traction radiography was performed under fluoroscopy with a force of 5 kg applied to the thumb. In the normal wrists, this led to selective widening of the scapholunate joint space whereas the lunotriquetral distance remained unchanged. In 25 healthy right wrists, the median scapholunate distance measured 2.1 (range 1.3–2.6) mm on resting radiographs and 2.2 (range 1.7–3.5) mm on the stress radiographs. For the 22 wrists with complete scapholunate ligament tears, the median scapholunate distance was increased from 2.0 (range 1.0–3.0) mm to 3.8 (range 3.0–5.5) mm by traction (median difference of 1.8 (range 1.0–3.0) mm). In conclusion, a scapholunate distance of 3.0 mm or more in unloaded wrists or widening of the scapholunate interval by 1.0 mm or more under thumb traction should both be considered as pathological findings. We recommend traction radiography as a simple and valuable diagnostic procedure for suspected scapholunate ligament injury. Journal of Hand Surgery (British and European Volume, 2005) 30B: 5: 464–467 Keywords: scapholunate ligament tear, traction radiography, diagnosis, arthroscopy
INTRODUCTION
Technique of traction radiography
Scapholunate ligament injury is the most frequent ligamentous injury of the wrist (Garcia-Elias, 1999). Numerous publications have dealt with its specific diagnostic and treatment dilemmas. Krimmer et al. (1996) and Watson et al. (1993) have classified scapholunate ligament injuries as partial tears without instability (Grade 1), complete tears with dynamic instability (Grade 2) and complete tears with static instability due to additional extrinsic ligament injury (Grade 3). Grade 1 ligament injury is only diagnosed by arthroscopy and static instability is obvious on standard dorsopalmar and lateral radiographs of the wrist (due to the DISI-position of the scaphoid and lunate and the increased scapholunate joint space). Dynamic instability may be demonstrable as a widening of scapholunate gap in special radiographic views when the wrist is moved or stressed. However, these stress views may be difficult to obtain after an acute injury, when the wrist is painful, and all suspected cases must be confirmed by arthroscopy, which remains the gold standard of diagnosis. The aim of this paper is to present and validate a new method of radiographic diagnosis of scapholunate ligament tear.
The patient was positioned supine on an examination table with his/her arm abducted and the elbow flexed to 901. The thumb was held in a Chinese finger trap and a traction force was applied to the upper arm with a 5 kg weight. Fluoroscopy was performed in the posteroanterior plane, first without traction and, then, with traction (Fig 1). The ulnar border of the hand was elevated 101 to 201 to avoid overlapping of the adjacent articular surfaces of the scaphoid and lunate (Kindynis et al., 1990; Moneim, 1981). Thus, good views of the scapholunate gap were obtained in all cases. Prints of the fluoroscopic pictures were taken and the scapholunate distance was measured from the proximal ulnarmost corner of the scaphoid to the proximal radial-most corner of the lunate (Fig 2), as described by Cautilli and Wehbe´ (1991). The lunotriquetral distance was measured in the same way for comparison (Fig 3). Examination of normal wrists The right wrists of 25 healthy volunteers were examined. There were 16 men and nine women, with an average age of 33 (range 22–57) years. Exclusion criteria were pre-existing injuries and diseases or complaints of the wrist and hand.
PATIENTS AND METHODS
Examination of injured wrists
This study was carried out with ethical committee approval and informed consent was obtained from all participants.
The wrists of 22 patients with arthroscopically proven, scapholunate ligament tears were recruited 464
ARTICLE IN PRESS TRACTION RADIOGRAPHIC DIAGNOSIS
465
Fig 1 Position of the patient and arrangement of the fluoroscope during traction radiography. Fig 3 Arthroscopic proven dynamic scapholunate instability in a 39year-old woman. Widening of scapholunate gap from (a) 2.5 mm to (b) 5.5 mm under thumb traction.
consecutively. All had sustained a hyperextension injury due to a fall on the outstretched hand. There were 14 men and eight women with an average age of 44 (range 20–70) years. Nineteen of them had fractures of the distal radius, one a scaphoid fracture and two were first diagnosed with a ‘‘sprained’’ wrist. Traction radiography was always performed as part of their initial treatment. Traction radiography was performed under local anaesthesia, before the fracture was reduced in patients with distal radius fractures. Wrist arthroscopy was performed in all 22 patients, following the radiographic examination, to determine the diagnosis. Scapholunate ligament injuries were classified according to Krimmer et al. (1996) and Watson et al. (1993). Radiographic analysis Fig 2 Measurement of the scapholunate distance. The distance was measured from the proximal ulnar-most corner of the scaphoid to the proximal radial-most corner of the lunate.
An independent radiologist, who was unaware of the history of the patients and the arthroscopic findings, performed the radiographic analysis. The measurements
ARTICLE IN PRESS 466
THE JOURNAL OF HAND SURGERY VOL. 30B No. 5 OCTOBER–2005
Table 1—Scapholunate and lunotriquetral distance in 25 normal right wrists Unloaded (mm)
Traction (mm)
Scapholunate distance Median Range
2.1 1.3–2.6
2.2 1.7–3.5
Lunotriquetral distance Median Range
1.3 1.3–2.5
1.3 1.3–2.5
Table 2—Scapholunate distance in 22 wrists with scapholunate ligament tears
Scapholunate distance Median Range
Unloaded (mm)
Traction (mm)
2.0 1.0–3.0
3.8 3.0–5.5
DISCUSSION were made in a blinded fashion on anonymous and unpaired X-rays, with the assessor unaware whether the radiographs were obtained with, or without, traction. Statistical methods The ordinal data was analysed using a non-parametric two-sided test for paired samples (Wilcoxon test).
RESULTS Normal wrists The median scapholunate gap was 2.1 (range 1.3–2.6) mm for the 25 normal right wrists (Table 1). Traction caused slight widening of the scapholunate gap to a median value of 2.2 (range 1.7–3.5) mm. Thus, in the normal right wrists, the median scapholunate distance was increased by traction by 0.1 (range 0.0–0.9) mm. Although small, this difference was highly significant ðP ¼ 0:004Þ: In contrast, traction only increased the lunotriquetral gap in one volunteer. Injured wrists All 22 patients had a complete rupture of the scapholunate interosseous ligament, but with no radiological evidence of abnormal tilt of the scaphoid or the lunate. Thus, all the injuries were classified as dynamic instabilities (Grade 2) (Krimmer et al., 1996; Watson et al., 1993). None of the patients had a degenerative ligament tear. The median scapholunate distance in these 22 patients with scapholunate ligament tears was increased by traction from 2.0 (range 1.0–3.0) mm to 3.8 (range 3.0–5.5) mm (Po0.001) (Table 2). This is a median difference of 1.8 (range 1.0–3.0) mm. In three patients with displaced sagittal articular fractures of the distal radius, thumb traction led to a clear step-off deformity in Gilula’s lines (Gilula, 1979). These carpal lines were normal in the remaining 16 cases with distal radius fractures.
Arthroscopy is considered as the gold standard for the diagnosis of scapholunate ligament tears (Cooney, 1993; Richards et al., 1997; Ruch and Bowling, 1998; Sennwald et al., 1996). However, it is the final step in the diagnostic procedure and its disadvantages include the possible complications resulting from anaesthesia and tissue damage, as well as its cost. Therefore, radiographic examination remains indispensable for the diagnosis of presumed ligament injuries of the wrist. Routine posteroanterior and lateral views may indicate scapholunate instability by revealing an increased scapholunate gap, a DISI-position of scaphoid and lunate, a cortical ring sign, a step-off in the continuity of Gilula’s lines or a lack of parallelism of the apposing joint surfaces of lunate and scaphoid (Garcia–Elias, 1999). It is sometimes difficult to obtain good views of the scapholunate gap in the posteroanterior view. To eliminate the overlapping of the lunate and scaphoid, Moneim (1981) recommended obtaining these radiographs with 201 of ulnar elevation and Kindynis et al. (1990) proposed 101 angulation of the X-ray tube from the ulna towards the radius. We recommend 101 to 201 of ulnar elevation and found that fluoroscopy allowed the ideal wrist position to be determined for each patient. Widening of the scapholunate interval might be accentuated by applying forces to the wrist. Dobyns et al. (1975) suggested an anteroposterior view taken while clenching the fist to apply a longitudinal compression force. Distraction views with the hand suspended in finger traps were recommended by Green and O’Brien (1980), to give better visualization of bone disorders. Traction radiography was first described by Fortems et al. (1994), who applied 2 and 5 kg longitudinal traction on the wrist using Chinese finger traps applied to the index, middle and ring fingers. This was performed in a prospective study on 20 patients with chronic wrist pain. Arthroscopy was used to determine the diagnosis and it was concluded that traction radiography had no value for the evaluation of intrinsic ligament ruptures. Yamaguchi et al. (1998) found the carpal stretch test helpful for identifying occult and dynamic scapholunate ligament injuries. In their study, 11 cadaver wrists and
ARTICLE IN PRESS TRACTION RADIOGRAPHIC DIAGNOSIS
40 normal wrists from 20 volunteers were examined. The positioning of the patient and the wrist was similar to ours, but they used the index and middle fingers to suspend the hand. The stretch test did not affect the normal wrists, but sequential sectioning of extrinsic and intrinsic ligaments in the cadaver wrists caused an increasing number of step-off deformities at the scapholunate joint. Unfortunately, the scapholunate gap was not measured. In this study, force was applied to the wrist by 5 kg traction on the thumb and this caused selective widening of the scapholunate gap in normal wrists. Our use of the thumb, rather than the index, middle and ring fingers probably explains why our findings are different to those of Fortems et al. (1994). Traction applied to the index and middle fingers, as done during the carpal stretch test of Yamaguchi et al. (1998), may disrupt Gilula’s lines. Obviously, thumb traction alone is more selective for widening of the scapholunate joint space and is also able to accentuate step-off deformities. There is still controversy about the value for a normal scapholunate gap. Measurement of the scapholunate interval in 25 normal wrists in our study showed a median scapholunate gap of 2.1 (range 1.3–2.6) mm. Kindynis et al. (1990) found a mean scapholunate distance of 1.3 (range 1–2) mm. in 14 cadaveric wrists and Moneim (1981) reported a mean scapholunate gap of 1.6 (range 0–2) mm. in eight volunteers. In contrast, Cautilli and Wehbe´ (1991) found a much larger mean scapholunate distance of 3.7 (range 2.5–5) mm in standard radiographs of 100 asymptomatic wrists. Thumb traction in normal wrists only resulted in minor increases in the scapholunate distance (median: 0.1 mm, range 0.0–0.9 mm). However, the scapholunate interval was enlarged by 1.8 (range 1.0–3.0) mm in the patients with arthroscopically confirmed ligament tears. As Fortems et al. (1994) and Yamaguchi et al. (1998) did not measure the scapholunate distance under traction, our values should be used as standards for clinical practice. We would consider a scapholunate distance of 3.0 mm, or larger, in an unloaded wrist as suspicious of a significant scapholunate ligament tear. Widening of the scapholunate gap by 1.0 mm, or more, under thumb traction should be regarded as pathological and suggesting dynamic scapholunate instability.
Acknowledgements The authors would like to thank Mrs. Professor Madeleine Ennis (Queen’s University of Belfast) for linguistic review.
467
References Cautilli P, Wehbe´ MA (1991). Scapho-lunate distance and cortical ring sign. Journal of Hand Surgery, 16A: 501–503. Cooney WP (1993). Evaluation of chronic wrist pain by arthrography, arthroscopy and arthrotomy. Journal of Hand Surgery, 18A: 815–822. Dobyns JH, Linscheid RL, Chao EYS, Weber ER, Swanson GE (1975). Traumatic instability of the wrist. Instructional Course Lectures, 24: 182–199. Fortems Y, Mawhinney I, Lawrence T, Stanley JK (1994). Traction radiographs in the diagnosis of chronic wrist pain. Journal of Hand Surgery British and European Volume, 19B: 334–337. Garcia-Elias M. Carpal instabilities and dislocations. In: Green DP, Hotchkiss RN, Pederson WC (Eds) Operative hand surgery, New York, Churchill Livingstone, 1999: 865–928. Gilula LA (1979). Carpal injuries: analytic approach and case exercise. American Journal of Roentgenology, 133: 503–517. Green DP, O’Brien ET (1980). Classification and management of carpal dislocations. Clinical Orthopaedics and Related Research, 149: 55–72. Kindynis P, Resnick D, Kang HS, Haller J, Sartoris DJ (1990). Demonstration of the scapholunate space with radiography. Radiology, 175: 278–280. Krimmer H, Hahn P, Prommersberger KJ, Sauerbier M, Lanz U (1996). Diagnostik und Therapie der Skapholuna¨ren Dissoziation. Aktuelle Traumatologie, 26: 264–269. Moneim MS (1981). The tangential posteroanterior radiograph to demonstrate scapholunate dissociation. Journal of Bone and Joint Surgery, 63A: 1324–1326. Richards RS, Bennett JD, Roth JH, Milne Jr. KJ (1997). Arthroscopic diagnosis of intra-articular soft tissue injuries associated with distal radial fractures. Journal of Hand Surgery, 22A: 772–776. Ruch DS, Bowling J (1998). Arthroscopic assessment of carpal instability. Arthroscopy: The Journal of Arthoscopic and Related Surgery, 14: 675–681. Sennwald GR, Fischer M, Zdravkovic V (1996). The value of arthroscopy in the evaluation of carpal instability. Bulletin Hospital for Joint Diseases, 54: 186–189. Watson HK, Ottoni L, Pitts EC, Handal AG (1993). Rotary subluxation of the scaphoid: a spectrum of instability. Journal of Hand Surgery British and European Volume, 18B: 62–64. Yamaguchi S, Beppu M, Matsushita K, Takahashi K (1998). The carpal stretch test at the scapholunate joint. Journal of Hand Surgery, 23A: 617–625. Received: 24 March 2003 Accepted after revision: 25 April 2005 Michael Scha¨del-Ho¨pfner, MD, Department of Traumatology and Hand Surgery, University Hospital, BaldingerstraXe, D – 35033 Marburg, Germany. Tel.: +49 0 6421 2866216; fax: +49 0 6421 2866721. E-mail: [email protected]
r 2005 The British Society for Surgery of the Hand. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhsb.2005.04.017 available online at http://www.sciencedirect.com
The diagnosis of scapholunate ligament injury by traction radiography was investigated within a consecutive study. The right wrists of 25 healthy volunteers and 22 wrists with arthroscopically proven complete scapholunate ligament tears were examined. Traction radiography was performed under fluoroscopy with a force of 5 kg applied to the thumb. In the normal wrists, this led to selective widening of the scapholunate joint space whereas the lunotriquetral distance remained unchanged. In 25 healthy right wrists, the median scapholunate distance measured 2.1 (range 1.3–2.6) mm on resting radiographs and 2.2 (range 1.7–3.5) mm on the stress radiographs. For the 22 wrists with complete scapholunate ligament tears, the median scapholunate distance was increased from 2.0 (range 1.0–3.0) mm to 3.8 (range 3.0–5.5) mm by traction (median difference of 1.8 (range 1.0–3.0) mm). In conclusion, a scapholunate distance of 3.0 mm or more in unloaded wrists or widening of the scapholunate interval by 1.0 mm or more under thumb traction should both be considered as pathological findings. We recommend traction radiography as a simple and valuable diagnostic procedure for suspected scapholunate ligament injury. Journal of Hand Surgery (British and European Volume, 2005) 30B: 5: 464–467 Keywords: scapholunate ligament tear, traction radiography, diagnosis, arthroscopy
INTRODUCTION
Technique of traction radiography
Scapholunate ligament injury is the most frequent ligamentous injury of the wrist (Garcia-Elias, 1999). Numerous publications have dealt with its specific diagnostic and treatment dilemmas. Krimmer et al. (1996) and Watson et al. (1993) have classified scapholunate ligament injuries as partial tears without instability (Grade 1), complete tears with dynamic instability (Grade 2) and complete tears with static instability due to additional extrinsic ligament injury (Grade 3). Grade 1 ligament injury is only diagnosed by arthroscopy and static instability is obvious on standard dorsopalmar and lateral radiographs of the wrist (due to the DISI-position of the scaphoid and lunate and the increased scapholunate joint space). Dynamic instability may be demonstrable as a widening of scapholunate gap in special radiographic views when the wrist is moved or stressed. However, these stress views may be difficult to obtain after an acute injury, when the wrist is painful, and all suspected cases must be confirmed by arthroscopy, which remains the gold standard of diagnosis. The aim of this paper is to present and validate a new method of radiographic diagnosis of scapholunate ligament tear.
The patient was positioned supine on an examination table with his/her arm abducted and the elbow flexed to 901. The thumb was held in a Chinese finger trap and a traction force was applied to the upper arm with a 5 kg weight. Fluoroscopy was performed in the posteroanterior plane, first without traction and, then, with traction (Fig 1). The ulnar border of the hand was elevated 101 to 201 to avoid overlapping of the adjacent articular surfaces of the scaphoid and lunate (Kindynis et al., 1990; Moneim, 1981). Thus, good views of the scapholunate gap were obtained in all cases. Prints of the fluoroscopic pictures were taken and the scapholunate distance was measured from the proximal ulnarmost corner of the scaphoid to the proximal radial-most corner of the lunate (Fig 2), as described by Cautilli and Wehbe´ (1991). The lunotriquetral distance was measured in the same way for comparison (Fig 3). Examination of normal wrists The right wrists of 25 healthy volunteers were examined. There were 16 men and nine women, with an average age of 33 (range 22–57) years. Exclusion criteria were pre-existing injuries and diseases or complaints of the wrist and hand.
PATIENTS AND METHODS
Examination of injured wrists
This study was carried out with ethical committee approval and informed consent was obtained from all participants.
The wrists of 22 patients with arthroscopically proven, scapholunate ligament tears were recruited 464
ARTICLE IN PRESS TRACTION RADIOGRAPHIC DIAGNOSIS
465
Fig 1 Position of the patient and arrangement of the fluoroscope during traction radiography. Fig 3 Arthroscopic proven dynamic scapholunate instability in a 39year-old woman. Widening of scapholunate gap from (a) 2.5 mm to (b) 5.5 mm under thumb traction.
consecutively. All had sustained a hyperextension injury due to a fall on the outstretched hand. There were 14 men and eight women with an average age of 44 (range 20–70) years. Nineteen of them had fractures of the distal radius, one a scaphoid fracture and two were first diagnosed with a ‘‘sprained’’ wrist. Traction radiography was always performed as part of their initial treatment. Traction radiography was performed under local anaesthesia, before the fracture was reduced in patients with distal radius fractures. Wrist arthroscopy was performed in all 22 patients, following the radiographic examination, to determine the diagnosis. Scapholunate ligament injuries were classified according to Krimmer et al. (1996) and Watson et al. (1993). Radiographic analysis Fig 2 Measurement of the scapholunate distance. The distance was measured from the proximal ulnar-most corner of the scaphoid to the proximal radial-most corner of the lunate.
An independent radiologist, who was unaware of the history of the patients and the arthroscopic findings, performed the radiographic analysis. The measurements
ARTICLE IN PRESS 466
THE JOURNAL OF HAND SURGERY VOL. 30B No. 5 OCTOBER–2005
Table 1—Scapholunate and lunotriquetral distance in 25 normal right wrists Unloaded (mm)
Traction (mm)
Scapholunate distance Median Range
2.1 1.3–2.6
2.2 1.7–3.5
Lunotriquetral distance Median Range
1.3 1.3–2.5
1.3 1.3–2.5
Table 2—Scapholunate distance in 22 wrists with scapholunate ligament tears
Scapholunate distance Median Range
Unloaded (mm)
Traction (mm)
2.0 1.0–3.0
3.8 3.0–5.5
DISCUSSION were made in a blinded fashion on anonymous and unpaired X-rays, with the assessor unaware whether the radiographs were obtained with, or without, traction. Statistical methods The ordinal data was analysed using a non-parametric two-sided test for paired samples (Wilcoxon test).
RESULTS Normal wrists The median scapholunate gap was 2.1 (range 1.3–2.6) mm for the 25 normal right wrists (Table 1). Traction caused slight widening of the scapholunate gap to a median value of 2.2 (range 1.7–3.5) mm. Thus, in the normal right wrists, the median scapholunate distance was increased by traction by 0.1 (range 0.0–0.9) mm. Although small, this difference was highly significant ðP ¼ 0:004Þ: In contrast, traction only increased the lunotriquetral gap in one volunteer. Injured wrists All 22 patients had a complete rupture of the scapholunate interosseous ligament, but with no radiological evidence of abnormal tilt of the scaphoid or the lunate. Thus, all the injuries were classified as dynamic instabilities (Grade 2) (Krimmer et al., 1996; Watson et al., 1993). None of the patients had a degenerative ligament tear. The median scapholunate distance in these 22 patients with scapholunate ligament tears was increased by traction from 2.0 (range 1.0–3.0) mm to 3.8 (range 3.0–5.5) mm (Po0.001) (Table 2). This is a median difference of 1.8 (range 1.0–3.0) mm. In three patients with displaced sagittal articular fractures of the distal radius, thumb traction led to a clear step-off deformity in Gilula’s lines (Gilula, 1979). These carpal lines were normal in the remaining 16 cases with distal radius fractures.
Arthroscopy is considered as the gold standard for the diagnosis of scapholunate ligament tears (Cooney, 1993; Richards et al., 1997; Ruch and Bowling, 1998; Sennwald et al., 1996). However, it is the final step in the diagnostic procedure and its disadvantages include the possible complications resulting from anaesthesia and tissue damage, as well as its cost. Therefore, radiographic examination remains indispensable for the diagnosis of presumed ligament injuries of the wrist. Routine posteroanterior and lateral views may indicate scapholunate instability by revealing an increased scapholunate gap, a DISI-position of scaphoid and lunate, a cortical ring sign, a step-off in the continuity of Gilula’s lines or a lack of parallelism of the apposing joint surfaces of lunate and scaphoid (Garcia–Elias, 1999). It is sometimes difficult to obtain good views of the scapholunate gap in the posteroanterior view. To eliminate the overlapping of the lunate and scaphoid, Moneim (1981) recommended obtaining these radiographs with 201 of ulnar elevation and Kindynis et al. (1990) proposed 101 angulation of the X-ray tube from the ulna towards the radius. We recommend 101 to 201 of ulnar elevation and found that fluoroscopy allowed the ideal wrist position to be determined for each patient. Widening of the scapholunate interval might be accentuated by applying forces to the wrist. Dobyns et al. (1975) suggested an anteroposterior view taken while clenching the fist to apply a longitudinal compression force. Distraction views with the hand suspended in finger traps were recommended by Green and O’Brien (1980), to give better visualization of bone disorders. Traction radiography was first described by Fortems et al. (1994), who applied 2 and 5 kg longitudinal traction on the wrist using Chinese finger traps applied to the index, middle and ring fingers. This was performed in a prospective study on 20 patients with chronic wrist pain. Arthroscopy was used to determine the diagnosis and it was concluded that traction radiography had no value for the evaluation of intrinsic ligament ruptures. Yamaguchi et al. (1998) found the carpal stretch test helpful for identifying occult and dynamic scapholunate ligament injuries. In their study, 11 cadaver wrists and
ARTICLE IN PRESS TRACTION RADIOGRAPHIC DIAGNOSIS
40 normal wrists from 20 volunteers were examined. The positioning of the patient and the wrist was similar to ours, but they used the index and middle fingers to suspend the hand. The stretch test did not affect the normal wrists, but sequential sectioning of extrinsic and intrinsic ligaments in the cadaver wrists caused an increasing number of step-off deformities at the scapholunate joint. Unfortunately, the scapholunate gap was not measured. In this study, force was applied to the wrist by 5 kg traction on the thumb and this caused selective widening of the scapholunate gap in normal wrists. Our use of the thumb, rather than the index, middle and ring fingers probably explains why our findings are different to those of Fortems et al. (1994). Traction applied to the index and middle fingers, as done during the carpal stretch test of Yamaguchi et al. (1998), may disrupt Gilula’s lines. Obviously, thumb traction alone is more selective for widening of the scapholunate joint space and is also able to accentuate step-off deformities. There is still controversy about the value for a normal scapholunate gap. Measurement of the scapholunate interval in 25 normal wrists in our study showed a median scapholunate gap of 2.1 (range 1.3–2.6) mm. Kindynis et al. (1990) found a mean scapholunate distance of 1.3 (range 1–2) mm. in 14 cadaveric wrists and Moneim (1981) reported a mean scapholunate gap of 1.6 (range 0–2) mm. in eight volunteers. In contrast, Cautilli and Wehbe´ (1991) found a much larger mean scapholunate distance of 3.7 (range 2.5–5) mm in standard radiographs of 100 asymptomatic wrists. Thumb traction in normal wrists only resulted in minor increases in the scapholunate distance (median: 0.1 mm, range 0.0–0.9 mm). However, the scapholunate interval was enlarged by 1.8 (range 1.0–3.0) mm in the patients with arthroscopically confirmed ligament tears. As Fortems et al. (1994) and Yamaguchi et al. (1998) did not measure the scapholunate distance under traction, our values should be used as standards for clinical practice. We would consider a scapholunate distance of 3.0 mm, or larger, in an unloaded wrist as suspicious of a significant scapholunate ligament tear. Widening of the scapholunate gap by 1.0 mm, or more, under thumb traction should be regarded as pathological and suggesting dynamic scapholunate instability.
Acknowledgements The authors would like to thank Mrs. Professor Madeleine Ennis (Queen’s University of Belfast) for linguistic review.
467
References Cautilli P, Wehbe´ MA (1991). Scapho-lunate distance and cortical ring sign. Journal of Hand Surgery, 16A: 501–503. Cooney WP (1993). Evaluation of chronic wrist pain by arthrography, arthroscopy and arthrotomy. Journal of Hand Surgery, 18A: 815–822. Dobyns JH, Linscheid RL, Chao EYS, Weber ER, Swanson GE (1975). Traumatic instability of the wrist. Instructional Course Lectures, 24: 182–199. Fortems Y, Mawhinney I, Lawrence T, Stanley JK (1994). Traction radiographs in the diagnosis of chronic wrist pain. Journal of Hand Surgery British and European Volume, 19B: 334–337. Garcia-Elias M. Carpal instabilities and dislocations. In: Green DP, Hotchkiss RN, Pederson WC (Eds) Operative hand surgery, New York, Churchill Livingstone, 1999: 865–928. Gilula LA (1979). Carpal injuries: analytic approach and case exercise. American Journal of Roentgenology, 133: 503–517. Green DP, O’Brien ET (1980). Classification and management of carpal dislocations. Clinical Orthopaedics and Related Research, 149: 55–72. Kindynis P, Resnick D, Kang HS, Haller J, Sartoris DJ (1990). Demonstration of the scapholunate space with radiography. Radiology, 175: 278–280. Krimmer H, Hahn P, Prommersberger KJ, Sauerbier M, Lanz U (1996). Diagnostik und Therapie der Skapholuna¨ren Dissoziation. Aktuelle Traumatologie, 26: 264–269. Moneim MS (1981). The tangential posteroanterior radiograph to demonstrate scapholunate dissociation. Journal of Bone and Joint Surgery, 63A: 1324–1326. Richards RS, Bennett JD, Roth JH, Milne Jr. KJ (1997). Arthroscopic diagnosis of intra-articular soft tissue injuries associated with distal radial fractures. Journal of Hand Surgery, 22A: 772–776. Ruch DS, Bowling J (1998). Arthroscopic assessment of carpal instability. Arthroscopy: The Journal of Arthoscopic and Related Surgery, 14: 675–681. Sennwald GR, Fischer M, Zdravkovic V (1996). The value of arthroscopy in the evaluation of carpal instability. Bulletin Hospital for Joint Diseases, 54: 186–189. Watson HK, Ottoni L, Pitts EC, Handal AG (1993). Rotary subluxation of the scaphoid: a spectrum of instability. Journal of Hand Surgery British and European Volume, 18B: 62–64. Yamaguchi S, Beppu M, Matsushita K, Takahashi K (1998). The carpal stretch test at the scapholunate joint. Journal of Hand Surgery, 23A: 617–625. Received: 24 March 2003 Accepted after revision: 25 April 2005 Michael Scha¨del-Ho¨pfner, MD, Department of Traumatology and Hand Surgery, University Hospital, BaldingerstraXe, D – 35033 Marburg, Germany. Tel.: +49 0 6421 2866216; fax: +49 0 6421 2866721. E-mail: [email protected]
r 2005 The British Society for Surgery of the Hand. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhsb.2005.04.017 available online at http://www.sciencedirect.com