Abstract
Purpose Lateral-Oblique projection of carpal scaphoid is a new method for improving the detection rate of carpal scaphoid fracture and displacement.
Materials and methods 46 patients with carpal scaphoid injury were collected with 41 males and 5 females, 14 cases of left wrist were injured and 32 cases of right wrist were injured. All the patients were given standard posterior-anterior(PA) and lateral projections of wrist, PA wrist-ulnar Flexion, and supplemented by lateral-oblique projection of carpal scaphoid. Through the statistical matching designⅹ², a comparative analysis of fracture detections and displacements was made.
Results All of the 46 patients with carpal scaphoid injury were first given posterior-anterior(PA) and lateral projections of wrist and PA wrist-ulnar Flexion, and 38 cases were diagnosed as carpal scaphoid fracture. After lateral-oblique projection of scaphoid was applied, 44 cases were diagnosed as carpal scaphoid fracture and 6 cases were found to be misdiagnosed. The difference is statistically significant. Meanwhile, 41 patients (including 38 cases of carpal scaphoid fracture and three cases of suspected fracture) were given lateral-oblique projection of carpal scaphoid, 15 more cases were found to be with displacements, and the difference is statistically significant. 8 cases still showed suspected carpal scaphoid fracture in spite of the negative results of lateral-oblique projection of carpal scaphoid and ulnar deviated view. When compared with making use of computed tomography (CT) to test the patients, the diagnostic sensitivity and accuracy of lateral-oblique projection of carpal scaphoid are 85.7% and 87.5% respectively, fracture patient was neglect by lateral-oblique projection of carpal scaphoid.
Conclusion Traditional PA wrist-ulnar Flexion in combination with lateral-oblique projection of carpal scaphoid can detect the carpal scaphoid fracture and displacement more accurately, lower the rate of misdiagnosis.
Key words. Dislocation. Digital radiography. Fracture. Scaphoid bone
Introduction
Carpal scaphoid fracture is a common injury that accounts for 82% and 89% of carpal fractures [1]. The traditional radiographic diagnosis is composed of PA and lateral projections of wrist in combination with PA wrist-ulnar Flexion[2]. Due to its irregular shape, adjacent relationship with surrounding carpi, and extent of injury, carpal scaphoid fracture can be appeared different degrees of fractures and displacements by the traditional examination. Without the assistance of computed tomography(CT) or magnetic resonance imaging(MRI)[3], it is difficult to detect the correct diagnosis based on the frontal projection only. The authors can describe the shape of carpal scaphoid from different perspectives, enhance the correct rates of diagnosis of carpal scaphoid fractures and displacements, and avoid misdiagnosis by a novel method named lateral-oblique projection of carpal scaphoid. Consequently, a more scientific and reliable evidence can be provided for further clinical judgment and treatment.
Materials and Methods
Clincal datum 46 patients with carpal scaphoid injury were collected, with 41 males and 5 females. Their ages range from 17 to 58 years old (the average age is 31). Among them, 14 cases were left carpal scaphoid
injury, and 32 cases were right carpal scaphoid injury. The institution
does not require IRB approval.
Instruments The Instruments applied in the study included the digital radiograph (DR) system SIEMENS AXIOM Aristos FX(Munchen Germany) and picture archiving and communication system(pacs) workstation(Beijing, China)
Examination Methods All of 46 patients were given traditional PA and lateral projections of wrist, PA wrist-ulnar Flexion to find the fractures and displacements of carpal scaphoid. On the basis of double blinded trial, three experienced radiologists were arranged to read the X-ray films.
After lateral-oblique projection of scaphoid was further given, a comparative analysis of fracture detections and displacements was made through the statistical matching design ⅹ². The highly suspected patients were examinated by CT and lateral-oblique projection of carpal scaphoid respectively, then we compare the sensibility and accuracy of two different methods that are applied to the patients clinically.
The specific method of lateral-oblique projection of carpal scaphoid
Radiographic position The patient was arranged on one side of the examination bed, kept the thumb straight, made the rest of fingers bent, placed the palm downward, kept proximal end of the thumb and distal end of the radius close to the center of the detector; raised the ulnar side in order to form a 45°angle between forearm coronal section and the
detector.(Figures 1A)
Central line The central line tilts toward the head side at a 20°angle, with the snuffbox of the first metacarpal directed toward the detector. (Figures 1B)
Presentation site The diagonal display of carpal scaphoid was slightly overlapped with os trapezium, with proximal end of metacarpal and distal end of radius and ulna presented in an oblique way. (Figures 1C)
Photography condition The film focus distance was 90cm,2.2mAs tube current,50 KV tube voltage, grid(-).
Statistical Analysis Make a comparative analysis about fracture rates and displacement rates were examined by routine method of PA and lateral projections of wrist, PA wrist-ulnar Flexion，and by the new method of lateral-oblique projection of carpal scaphoid. The datum obtained were tested through the statistical matching designⅹ²of SPSS 12.0 software(P﹤0.05), the result is statistically significant.
Results
46 patients received traditional carpal joint X-ray examinations, 38 of them showed carpal scaphoid fractures, 8 of them showed not obvious fractures. Supplemented by the newly-inovated method lateral-oblique projection of carpal scaphoid, 44 cases were found to be with carpal
scaphoid fractures, two cases showed no clear fractures, so six cases were
missed diagnosed according the traditional examination. The difference is statistically significant(P﹤0.05,ⅹ²=4.039 ，P=0.044), which indicates lateral-oblique projection of carpal scaphoid can enhance the detection rate of carpal scaphoid fracture. (Table 1)
41 patients (including 38 cases of carpal scaphoid fractures and 3 cases of suspected fractures) were examined by the routine PA and lateral projections of wrist, PA wrist-ulnar Flexion , six cases were found to be with displacements and 35 cases without displacements. Supplemented by Lateral-oblique projection of carpal scaphoid, 21 cases were found to be with displacements and 20 cases without displacements. The difference is statistically significant (P﹤0.05,ⅹ²=11.038 ，P=0.001). Among them, 10 patients were given internal fixation, the result of carpal scaphoid fixation showed good. Supplemented by Lateral-oblique projection of carpal scaphoid, 5 cases of carpal scaphoid fixation showed poor results (50%), which indicates a contritution to a comprehensive judgment about carpal scaphoid displacement and a precise evaluation about fracture reposition by surgery. (Table 2)
8 cases of suspected carpal scaphoid fractures were examinated by PA and lateral projections of wrist, and PA wrist-ulnar Flexion, no carpal
scaphoid fractures were found; 8 cases of suspected carpal scaphoid fractures were examinated by lateral-oblique projections of carpal
scaphoid, 6 fractures cases were found, 2 fractures cases were no found. Moreover, 8 cases of suspected carpal scaphoid fractures were examinated by CT, 7 fractures cases were found, 1 fracture case was no found, 1 fracture case was missed diagnosis. The different results show the positive detection rate of the suspected fractures patients increase markedly by lateral-oblique projections of carpal scaphoid. The diagnostic sensitivity and accuracy are 85.7% and 87.5% respectively.(Table 3)
Discussion
Based on Herbert classification, carpal scaphoid fractures can divided into four Types: Type A acute stable fracture, Type B acute unstable fracture, Type C delayed union fracture ,and Type D nonunion fracture [4]. 40 percent of poor prognosis can be attributed to missed diagnosis and misdiagnosis at early stage [5], the reason can be due to two main factors: one is the hidden location of carpal scaphoid in the sense of anatomy, the other is the choice of radiographic position of carpal scaphoid in the sense of digital radiography. If the patients were delayed diagnosis and treatment, a series of complications such as bone ununion, necrosis may occur and the the normal function of wrist can be affected.
Part of carpal scaphoid fractures missed diagnosis clinically ,because the results were negative at first X-ray examination,. 发生率达22％～43％[6]. At present, digital X-ray computed tomography fusion technology [7]or MRI[8-11] or CT [8,10-12]and CBCT [13,14] can be applied to the diagnosis of suspected carpal scaphoid fracture. However, radiography is the first choice in the diagnosis of scaphoid fractures, which usually involves the PA and lateral projections of wrist and PA wrist-ulnar Flexion. From the observation of image of carpal joints, scaphoids are short and scaphoid joints tend to overlap with the proximal end of scaphoid, which lead to unclear presentation of scaphoid fracture line. 能够显示腕舟状骨尺-桡方向骨折线的骨折和错位情况，但是单纯一个摄影体位，观察舟状骨的骨折情况是不全面的，对于腕舟状骨掌-背方向或斜方向的不全骨折，因其重叠而不能清晰显示。舟状骨侧（斜）位使舟状骨向内旋转接近45°，近似舟状骨侧位，能够清晰显示腕舟状骨掌-背方向或斜方向的骨折，弥补了单纯舟状骨尺偏位的不足。 If scaphoid fracture is suspected, PA wrist-ulnar Flexion should be given to adjust its physilogical bias. Thus, with the parallel of long axis of bone and spool box, minor fracture without displacement can be indicated. Meanwhile, through frontal projection images of carpal scaphoids, hidden fractures or incomplete fractures may not be observed. When patients present obvious injury mechanisms--- local swelling stuff box, significant tenderness or the positive results of carpal scaphoid movements, lateral-oblique projection of carpal scaphoid should be given if hidden scaphoid fracture is highly suspected in spite of the negative results of X-ray plain film examination. In this way, diagnosis can be clearer. 6 patients were diagnosed as carpal scaphoid fractures, 2 patients were not fractured.
Meanwhile, 8 patients were examined by CT, 7 patients were fractured, 1 patient was not fractured, and 1 patient was missed diagnosis, the
diagnostic sensitivity and accuracy of lateral-oblique projection of carpal scaphoid are 85.7% and 87.5% respectively. The result shows that lateral-oblique projection of carpal scaphoid as a method to diagnose the obscure fracture can enhance the detection rate of scaphoid fracture. No obvious fracture can be observed in the fifth case based on the standard PA and lateral projections of wrist, and PA wrist-ulnar Flexion.(Figures 2) But the patient complained of swelling snuff box, obvious tenderness, so carpal scaphoid fracture is highly suspected. Making use of lateral-oblique projection of scaphoid shows the carpal scaphoid fracture, which reflects the clinical significance of the technique of lateral-oblique projection in the diagnosis of hidden scaphoid fracture.If the suspected fractures patients were not examinated by lateral-oblique projection of carpal scaphoid, and then you can take advantage of CT or MRI to make a definite diagnosis.
The treatment method of carpal scaphoid fracture is determined by fracture displacement and stability, and accurate and complete imaging data can provide reliable support for the clinical treatment. 正常情况下，在腕舟状骨位中舟状骨的形态为“半月”形，而 (侧)斜位中其形态为“半椭圆形”，如果骨折断端有分离、错位，舟状骨形态随之改变，说明舟状骨呈不稳定状态。腕舟状骨骨折行内或外固定术后，建议拍摄腕舟状骨位和腕舟状骨(侧)斜位，以综合评价错位程度和复位效果。Upon the traditional radiographic examination, 10 patients with internal fixation of carpal scaphoid showed good recovery. However, with the assistance of lateral-oblique projection of carpal scaphoid, the radiograph showed five of them with poor recovery(50%), the hollow screws are in operation.(Figures 3) In order to get a clear and complete picture of carpal scaphoid, surgeons should apply lateral-oblique projection of carpal scaphoid in addition to ensure the reposition and fixation of carpal scaphoid in the course of clinical treatment. Therefore, PA wrist-ulnar Flexion combined with lateral-oblique projection of carpal scaphoid should be applied as a newly-innovated technique in scaphoid fracture surgeries.
The technique’s application provides a new perspective of detection of scaphoid fracture which can improve the clinical treatment. Consequently, we get a systematic and accurate method for testing the negative detection rates and condition of displacement. Besides, the method is also convenient, feasible, and can be widely applicable. Here, we have 6 cases were listed to further prove the clinical significance of lateral-oblique projection of carpal scaphoid (Figures 2-7).
In conclusion, PA wrist-ulnar Flexion should be applied along with the lateral-oblique projection of carpal scaphoid in the process of the clinical diagnosis and treatment. In this way, we can obtain more reliable imaging data that provides solid evidence for the treatment of scaphoid fractures.
