[Ultrasonic and radiographic quantification of palmar angulation in metacarpal IV and V neck fractures]. / Sonografische und röntgenologische Quantifizierung der Palmarabkippung von subkapitalen Frakturen der Metakarpalia IV und V.

PURPOSE/BACKGROUND: Therapy of metacarpal neck fractures depending on radiographically measured palmar angulation is discussed controversially in the literature. Some authors describe normal hand function of malunited metacarpal neck fractures with a palmar angulation up to 70°; others define 30° as the uppermost limit to maintain normal hand function. However, the methods of measuring palmar angulation are not clearly defined. Here, we present a new method to measure palmar angulation using ultrasound. The aim of this prospective study is to compare the radiographic methods of measuring palmar angulation with the ultrasound method. PATIENTS/MATERIAL AND METHOD: 20 patients with a neck fracture of the metacarpals IV or V were treated either conservatively or operatively. 2 weeks after trauma or operation, an x-ray was performed. 2 examiners measured the palmar angulation on the oblique and lateral projections using 2 different methods (medullary canal and dorsal cortex methods). At the same time, the 2 examiners performed measurements of palmar angulation using ultrasound. The measurements obtained with the different methods as well as by the 2 examiners at 2 different terms were compared. Intra- and interobserver reliability of each method was calculated, and for the ultrasound method a test for accuracy of the measured angles was performed. RESULTS: Depending on the method of radiographic measurement and different x-ray projections, an average of up to 20.3° higher angles were determined as compared with the ultrasound method. The average deviation in angles measured within and between the 2 examiners was lower for the ultrasound method than for the radiographic methods, corresponding to a higher degree of intra- and interobserver reliability. CONCLUSION: The ultrasound method for measuring palmar angulation in metacarpal neck fractures is simple, and appears to be more precise in comparison to radiographic methods. An exactly lateral projection of the fractured metacarpal bone can be imaged without superposition and exposure to radiation. The question arises whether previous studies that suggested normal hand function with palmar angulation up to 70° might have been based on too high angle-readings due to the use of radiographic methods.

Inter- and intraobserver reliability of predefined diagnostic levels in high-resolution sonography of the carpal tunnel syndrome - a validation study on healthy volunteers.

PURPOSE: High-resolution ultrasound is becoming increasingly important in the diagnosis of carpal tunnel syndrome (CTS). Most studies define cut-off values of the cross-sectional area (CSA) of the median nerve in different locations. The individual range of nerve swelling, the size of the nerve, and its CSA are not addressed. The aim of the study is to define the intra- and interobserver reliability of diagnostic ultrasound using two different cross-sectional areas of the median nerve at the carpal tunnel in predefined locations. MATERIALS AND METHODS: Two observers using high-resolution ultrasound examined 50 wrists of healthy volunteers independently. The CSA of the median nerve was measured at the entrance of the carpal tunnel and 2 cm proximal to the palmar wrist crease. The height and width of the carpal tunnel were determined using anatomical landmarks. The intra- and interobserver reliability was determined using Cronbach's alpha. RESULTS: Depending on the observer, the mean width of the carpal tunnel ranged from 3.37 to 3.43 cm with the height ranging from 1.18 and 1.19 cm. The CSA of the nerve was measured with values of 8.43 and 9.05 mm (2) on the pisiform level and 9.37 and 9.68 mm (2) on the proximal level. Cronbach's alpha ranged from 0.754 to 0.940 for the interobserver reliability and from 0.924 to 0.996 for the intraobserver reliability. CONCLUSION: To use high-resolution ultrasound for the diagnosis of carpal tunnel syndrome, the reproducibility of this method has to be evaluated. Our study confirms examiner-independent reproducibility of two predefined diagnostic cross-sectional areas resulting in good alpha values.