Carpal navicular fractures are a common disease in hand surgery. In clinical work, there are many studies on the mechanism of injury, clinical classification and treatment of various types of fractures and nonunion, but there are few studies on the immediate and long-term effects of such fractures on the synovial membrane of the wrist and its adjacent bones and joints, as well as on other ligament and soft tissue injuries of the wrist combined with the fracture in China. With the widespread use of wrist arthroscopy in clinical practice, it has enabled clinicians to have a more comprehensive visualization of the wrist joint while maintaining the basic anatomical integrity of the wrist joint, and has made the above study possible. Materials and methods 1. General data: Fifty-four cases of carpal navicular fractures treated surgically at the Department of Hand Surgery, Nagoya University Hospital, from 1995 to August 2001 were selected. 58 wrist arthroscopic examinations were performed in these patients before surgery (four cases were operated twice), and all had complete medical histories and examination records. 53 of the 54 patients were male and only one was female, aged 12 ~ 64 years (28.3 ± 12 years). Of the 54 patients, 53 were male and only one was female, with ages ranging from 12 to 64 years (28.3 ± 12.2 years). 26 cases of the affected wrist were left-sided and 28 cases were right-sided. 2. Causes of injury: 19 cases of sports injuries (including 10 cases of skiing, 7 cases of soccer, 1 case of baseball and 1 case of rugby), 13 cases of injuries caused by falls, 6 cases of injuries caused by falls from height, 6 cases of injuries caused by traffic accidents, and 10 cases of other traumatic injuries (including 3 cases of mechanical pressure injuries and 2 cases of injuries caused by fights, and the other 5 patients could not recall the traumatic injuries). 3. Preoperative diagnosis: 32 cases of navicular fracture and 22 cases of delayed healing or non-healing of navicular fracture were diagnosed preoperatively based on medical history, physical examination and imaging data. 4. The time from injury to wrist arthroscopy: the shortest was 4 days and the longest was 15 years. There were 2 cases within 1 week, 5 cases between 1 and 2 weeks, 5 cases between 2 and 4 weeks, 21 cases between 1 and 4 months, 9 cases between 4 and 12 months, and 16 cases over 1 year. Four cases were examined before the 2nd surgery. 5, Wrist arthroscopy method: under brachial plexus anesthesia, no tourniquet was routinely applied (only when more bleeding was found intraoperatively and affected the observation field), and the arthroscope was made of Stryker components with a caliber of 2.3 mm and an observation lens inclination of 30°, and the regular puncture and observation points were selected as 3-4 and RMC. When ulnar radial joint lesion is suspected, DRUJ point is selected, and drainage tube is placed at 6U point. 6. Contents of wrist arthroscopy: The main contents of the examination included 7 aspects such as synovial membrane, articular cartilage, palmar ligament, interosseous ligament, TFC, fracture line and others. Results Since the results of wrist arthroscopy after navicular fracture are more closely related to the time of injury, the following observations are described according to different tissues and different times. 1. Synovial changes: no significant abnormal synovial changes were observed in 2 patients within 1 week of injury; 2 of 5 patients from 1 to 2 weeks did not see synovial changes, 2 had mild synovial hyperplasia, and 1 had more synovial hyperplasia on the dorsal side of the radial carpal joint; all patients from 2 to 4 weeks saw synovial hyperplasia, 4 of 5 had radial hyperplasia, 2 had ulnar hyperplasia, and 1 had mild synovial hyperplasia of the midcarpal joint; 1 to 4 The remaining 15 patients all had radial carpal synovial hyperplasia, 6 with ulnar hyperplasia (3 with TFC injury), and 4 with midcarpal synovial hyperplasia; 9 patients from 4 to 12 months all had synovial hyperplasia, 2 of which were so severe that they had difficulty with mirror vision. The synovial hyperplasia was more concentrated in the mid-wrist joint (5 cases) and the navicular-large and small polygonal osteoarthritis (STT) (3 cases), in addition to the radial-wrist joint (5 cases) and the navicular-large and small polygonal osteoarthritis (STT) (3 cases). 2. Articular cartilage changes: In patients with disease duration within 1 month, apart from cartilage fracture or undermining of the navicular fracture, no other articular cartilage damage was observed; in patients with disease duration between 1 and 4 months, 6 cases were observed with articular cartilage fibrosis at different sites (the earliest case was 5 weeks after fracture), including the navicular and ulnar fossae of the radial articular surface (4 cases), the radial styloid process (1 case), and the proximal articular surface of the lunar and cephalic bones (1 case each); 4 cases were observed with articular cartilage fibrosis. In addition to fibrosis of the radial styloid process and distal radial articular surface in 4 to 12 months, two other patients had STT cancellous bone exposure and cartilage destruction of the radial styloid process; 11 cases over 1 year had articular cartilage fibrosis or destruction, including 4 cases involving the cephalic bone, and the most severe case had cartilage destruction of the navicular and lunar bones and their corresponding radial articular surfaces The most serious case was the complete destruction of the navicular bone, lunar bone and the corresponding cartilage of the radial articular surface (duration of disease was 33 months). 3.Lateral palmar ligament injury: Among the 54 patients, there were 9 cases of combined palmar ligament injury, and the main ligaments involved included the radial navicular head and radial navicular ligament. Injury manifestations within 2 weeks can be seen directly ligament rupture (4 cases), some with local hemorrhage (1 case); more than 2 weeks is manifested as ligament fibrosis, congestion and local synovial hyperplasia, covering. 4, interosseous ligament injury: In this group of patients, there were 18 cases of combined interosseous ligament injury, of which the navicular ligament injury was the most common (12 cases), followed by the lunotriquetral ligament (6 cases). The manifestations ranged from ligament congestion, laxity, and bulging to localized fibrosis and synovial hyperplasia, as well as partial or complete tearing of the ligament. While observing, a blunt probe was inserted from points 4-5 to check the interosseous range of motion, and five cases were found to have significantly increased range of motion. 5, TFC injury: A total of 12 patients had combined TFC injury, and in addition to the visible tear of the middle or radial attachment, some of them had local synovial hyperplasia and fibrosis. 6. Fracture line: The fracture line was visible in 46 of 58 microscopic examinations, and in all positive cases the fracture line could be seen at the midcarpal joint (RMC point), whereas in only 13 cases the fracture line could be seen at the radial carpal joint (3-4 points), and in 10 of these 13 cases obvious separation and misalignment of the severed ends were visible from the RMC, and in 2 cases the separation of the severed ends was large enough to allow access with the viewing scope. Another incidental finding was that in one patient with a second navicular fracture, two fracture lines were actually seen, one being a healed fracture line from the previous fracture and the other being a fresh fracture line this time (2 years between the two fractures). 7. Other findings: during the arthroscopic examination, two cases were found to have abnormal alignment of the carpal bones due to obvious dorsal intercalated segment instability (DISI) deformity of the proximal carpal bones; in one case, crystalline joint free bodies were seen in the carpal joint (15 years’ duration); in one postoperative patient, the original implant was seen on the proximal articular surface of the navicular bone. In one case, a crystalline joint free body was seen in the wrist joint (15 years old); in one postoperative patient, a bone redundancy was seen on the proximal articular surface of the navicular bone, and cartilage destruction existed on the articular surface of the radius. 8. Relationship between synovial hyperplasia and fracture displacement: Based on the above examination results, the patients were grouped according to the presence or absence of synovial hyperplasia and the presence or absence of significant fracture displacement, and the χ2 test was used, and the χ2 value was 0.64 (p>0.05), suggesting that there was no correlation between the two. From the results of the arthroscopic examination of this group, it could be seen that the proliferation of synovial tissue in the wrist joint underwent a wave-like process of waxing and waning with the development of the disease, with no or mild proliferation of synovial tissue in the early stage (within 1~2 weeks after injury); after 2 weeks, the severity of synovial lesions gradually increased and their involvement was slowly widespread (the sequence of lesion sites generally started from the radial carpal joint and radial tuberosity, and progressed to the ulnar After 1 year of disease, the synovial lesions are reduced in some patients and replaced by fibrous scar tissue; with the prolongation of the disease, the presence of DISI and non-healing of the navicular fracture (fibrosis of the lunate fossa of the radial articular surface within 4 months after the fracture also indicates the presence of DISI and its destruction), the late stage of “scaphoid non-union advanced collapse (SNAC) secondary to navicular non-union,” and the synovial reaction is again aggravated. This shows that the early stage of the fracture, with less synovial tissue production and insertion, provides a theoretical basis for the early closed reduction with percutaneous Herbert nail internal fixation carried out in recent years to achieve a better outcome. The appearance of late SNAC suggests that not only should the navicular fracture be anatomically repositioned as early as possible, but also the DISI deformity needs to be corrected at the same time as the navicular fracture is treated. Otherwise, patients with advanced SNAC can only be treated by local intercarpal fusion, carpal bone removal or total carpal fusion, which have a greater impact on wrist mobility. In addition, one patient observed in this group showed significant fibrosis of the articular cartilage of the distal radius 5 weeks after the injury, which also suggests that we should operate as early as possible to prevent severe articular cartilage destruction once poor healing after conservative treatment of navicular fractures is confirmed. In the previous treatment of navicular fractures, we often neglected the treatment of the concurrent ligament and other soft tissue injuries, and from the present examination, we found a total of 39 cases of combined metacarpal ligament, interosseous ligament and TFC injuries, which, if not treated promptly, often lead to wrist joint dysfunction even after the navicular fracture is healed, thus affecting the overall treatment effect. Since the distal end of the navicular fracture has a tendency to palmar flexion and the proximal end has a tendency to dorsal extension with the lunate (if the navicular ligament is not damaged), it can cause the fracture line to compress on the palmar radial side and separate on the dorsal ulnar side, so that the fracture line is easier to see by the midcarpal joint when observed with arthroscopy. The degree of fracture displacement and the presence or absence of steps in the fracture are more visualized and clearer with arthroscopy than with any other examination. This is certainly related to the different mechanisms of injury, but at least it shows that some of the navicular fractures are strong enough to withstand violent impact and heavy work after a 2-year healing process. In another case, the patient had a wrist injury 15 years ago and was immobilized in a cast for 4 weeks, after which he had no discomfort for 15 years and was engaged in casting work. This case suggests that there are cases of non-union of the navicular fracture without clinical symptoms, and the wrist pain is probably not due to the navicular fracture itself, but to the SNAC, and the intra-articular free bodies may be worn and broken articular cartilage. The third case is a postoperative patient who underwent arthroscopic examination six months after surgery due to postoperative joint pain and limitation of movement, and saw a bone ridge in the bone graft area of the navicular fracture, and the corresponding radial articular surface was worn, which on the one hand suggests that the implanted iliac bone can heal well, and on the other hand suggests that we should pay attention to maintaining the integrity and smoothness of the articular surfaces of the navicular bone during the bone grafting process in the future. Of course, since the above three cases may be chance, more similar cases need to be verified in the future.