MRI Study Of Ulnar Impaction Syndrome

Objective:To discuss the MRI manifestation of the ulnar impaction syndrome and the MRI grading of the abnormal arthrodial cartilage and the injured TFC.Methods:The patients of 56 cases aged from 15 to 80 years old, averaged 41.5 years old, there were 38 male, and 18 female. The syndrome of patients included different degree ulnar side pain on all patient's wrist, the limited flex-to-extension and rotation of the suffered hands, and the decreased gripping power of the suffered hands. All patients underwent MR scan by the machine of 0.23T made by PICKER company. The MR sequece included the coronal, transectional and sagital FE3D TIWI, STIR, PDWI and FSE T2WI by the wrist surface coil. In the coronal TIWI of the wrist, the middle line of the radio-ulnar joint was made as the standard, measured by GeIBerman etc. parallel line method to determine the positive, negative and the normal case of the ulna variation. Observed the injury predilection position, the shape and signal change of the malacic osteo-cartilage and the injured TFC, then calculated the incidence rate of the injuries and degenerations.According to the shape and signal changes of osteo-cartilage shown on MR images in these 56 cases, they were classified 4 grades.â… grade:the arthrodial cartilage were normal, but low TIWI and high STIR signal pieces with unsmooth margin were seen in subchondral bone marrow. Irregular low T1WI and STIR signal part were seen in subchondral bone tissue.â…¡grade:There were the irregulation in the formation of arthrodial cartilage and the small cystic focus of low T1WI and high STIR signal were seen in the cartilaginous opereulum, and low T1WI and high STIR signal patchy foci with unsmooth margin or sclerosic-margin cystic foci were seen in subchondral bone marrow, irregular low T1WI and STIR signal margin were seen in subchondral bone tissue.â…¢grade:there were attenuation of the arthrodial cartilage.â…£grade:the disappearance were seen in arthrodial cartilage and the articular surface were collapsed. Extensive low T1WI and high STIR signal pieces with unclear margin in subchondral bone marrow, low or equal T1WI and high STIR signal cystic foci with sclerotic margin in subchondral bone marrow, the irregular low T1WI and STIR signal foci in subchondral bone tissue were all seen inâ…¢andâ…£degree. We compared the MRI grade of the 56 cases (112positions) with their arthroscope grade (which was use Shahriaree standard) by the Crosstabulation Symmetric Measures.According to the changes of injured and degenerate triangular fibrocartilage shown on MR images and injured location, the they were classified 4 grades from mild to severe.â… grade:TFC were integrated, the articular surface were smooth and complete, little edema or degeneration were observed in the TFC which showed as the isolated high STIR signal spots in the STIR images.â…¡grade:the TFC were integrated, the articular surface were smooth and complete, the horizontal tearing not to extend the articular surface were seen in the TFC;â…¢A grade:the TFC were integrated, but the articular surface was not smooth and complete, the high STIR signal line extending the articular surface of TFC.â…¢B grade:the TFC were perforated centrally;â…¢C1 grade:the radial adherent part were discontinuous and high STIR signal piece in MRI;â…¢C2:the ulnar attachment of TFC were discontinuous (T2WI) high STIR signal pieces;â…¢C3:both radial and ulnar of TFC were discontinuous high STIR signal patch in MRI.â…£grade:ir-regulation of the whole cartilage disc, and the signal were confounding in MRI. And the all 56 cases were compared and analysed with the arthroscope and calculated the accuracy of the MRI grading.Results:The positive variation of the ulnae were 34, the negative were 10, and the neutral were 12. The MRI manifestation of the Ulnar Impaction Syndrome include:different degree damage and retrogression of the ulnar aspect of lunate, radius aspect of traquetrum, arthrodial cartilage of ulnarhead and TFC. The incidence rate of the injury and degeneration caused by the ulnar impaction syndrome was:on ulnar aspect of the lunate 94.64%(53/56), on radial aspect of the triquetrum 85.71%(48/56), on articular surface of the head of ulnae 55.36%(31/56), TFC 91.07%.In the MRI grade of these osteocartilage:normal 11 parts,â… grade 24,â…¡grade 57,â…¢grade 17,â…£grade 3. In arthroscope degree:normal 16,â… grade 20, â…¡grade 48,â…¢grade 25,â…£grade 3. With the Crosstabulation Symmetric Measures analysis the grade of MRI and arthroscope was concordant.In these cases, the TFC nomal 5 cases, and also normal in arthroscope;â… grade: 6, and they were integrated in arthroscope;â…¡grade:6,4 were integrated and 2 incomplete in arthroscope (one was teared at the articular surface, one perforated centrally);â…¢grade 34:3 were integrated and 31 were broken in arthroscope (in which, there were surface rupture or abrasion as "the Brush" in 8 cases, perferation centrally in 10, tearing of the radial attachment 9, tearing of the ulnar attachment 6, tearing of both radial and ulnar attachment 2);â…£grade:3 cases which were incomplete in arthroscope. The accuracy of MRI grading with the arthroscope wasâ… grade 100%(6/6),â…¡grade 66.67%(4/6),â…¢grade 86.11%(31/36);â…¢A grade 100% (6/6);â…¢B gradeS 1.82%(9/11);â…¢C1 grade 100%(8/8);â…¢C2 grade 75%(6/8);â…¢C3 grade 66.67%(2/3);â…£grade 100%(3/3). The whole accuracy was 86.27%(44/51).Conclusion:1,MRI can clearly show the different degree damage and retrogression in ulnar aspect of lunate, radius aspect of traquetrum, articular cartilage of the ulnar-head and the TFC disc. We can know the pathogenesis and make early diagnosis by analyzing imaging characters.2,MRI grading can exactly reflect the degree of the articular osteocartilage injury and degeneration caused by ulnar impaction syndrome, and which is helpful to direct the clinical treating methods.3,MRI classification is exactly for the TFC injury and degeneration caused by ulnar impaction syndrome and is helpful to direct the clinical treating methods.