Modified Palmer Classification Of Traumatic Triangular Fibrocartilage Complex Injury Based On Magnetic Resonance Imaging

Objective: The triangular fibrocartilage complex(TFCC)is a group of small anatomical structures located in the space between the distal ulnar of the ulnar and the lunate and triangular bones on the ulnar side of the wrist.The anatomical structure of the TFCC is complex,consisting of triangular fibrocartilage(TFC),meniscal homolog,palmar and dorsal distal radiulnar ligaments,ulnocarpal collateral ligaments,ulnar extensor carpal tendon sheath,ulnotriquetral ligament and ulnolunate ligament.The TFCC is often referred to as the "shock absorber" of the wrist.When the wrist is in front and back rotation,the TFCC can stabilize the radioulnar joint and effectively slow the axial impulse of the ulnar joint.TFCC injury is the main factor causing joint dorsi extension,rotation function decline and ulnar pain.A large number of studies have proved that the soft tissue of magnetic resonance imaging(MRI)has high resolution and clear image,which can sensitively display the anatomical structure and injury types of TFCC.With the continuous development of 3.0T magnetic resonance technology,we found that more types of TFCC injury are not suitable for the original Palmer classification method,so this study will apply 3.0T magnetic resonance to analyze and type the images of patients with traumatic triangular fibrocartilage complex injury.Methods: Ninety-nine patients with a clear history of wrist injuries admitted to the 81 st Group Military Hospital of the Chinese People’s Liberation Army from January 2021 to July 2022 were collected.A total of103 wrists were diagnosed with injuries,including 51 left wrist injuries,44 right wrist injuries,and 4 double wrist injuries.All patients underwent MRI examination within 3 days after trauma.According to the Palmer classification criteria,MRI findings were classified as follows: the focal structures of triangular fibrocartilage(the articular disc)(TFC)injury,the horizontal of the articular disc tear,injuries of ulnar styloid attachment and ulnar fovea attachment in TFC,ulnolunate and ulnotriquetral ligaments injuries,injury of the radial sigmoid notch junction,meniscal homolog injury,ulnar collateral ligament injury,ulnar extensor carpal tendon sheath injury.Some patients with surgical indications received wrist arthroscopic surgery,and all patients were re-examined with wrist MRI one month and three months after injury.SPSS 26.0 software was used for statistical analysis of the data,Kruskal-Wallis 1-way ANOVA test was used to compare the non-normal distribution data between groups,accuracy test(Fisher test)was used for classification data count data,to analyze whether the distribution of different injury types in different genders and ages was different.Results: A total of 103 cases of wrist joint were classified by Palmer method: 21 cases of type IA injury,30 cases of type IB injury,18 cases of type IC injury and 18 cases of type ID injury,and 16 with two or more types of injuries combined.The other 34 wrist joints were not suitable for Palmer classification,5 patients had horizontal tears in the articular disc,and 18 patients had meniscus homologous injuries,8 patients were diagnosed with ulnar collateral ligament injury,17 with ulnar extensor carpal tendon sheath injury,and 14 with two or more types of injuries combined.The results of non-parametric test showed that the age distribution of different subtypes had no statistical difference(P=0.320).Fisher’s test showed that the sex distribution of different subtypes was not statistically significant(P=0.998).Conclusions: Due to its advantages of high soft tissue resolution,zero ionizing radiation,non-invasive,and multi-angle and multi-parameter imaging,magnetic resonance examination is undoubtedly the best examination method for wrist injury.3.0 T magnetic resonance imaging can not only show various subtypes of Palmer classification,but also refine and supplement the classification based on the original classification,such as the ulnar styloid attachment and ulnar fovea attachment at the ulnar end of the articular disc,horizontal tear of the articular disc,meniscus homologous injury,etc.It is of great significance to be familiar with the complex anatomical structure and MRI manifestations of TFCC injury to accurately evaluate TFCC injury and guide the treatment.