Ulnar positive variance associated with TFCC foveal tear.

OBJECTIVE: The ulnar positive variance (UPV) can be observed on simple radiography due to a triangular fibrocartilage complex (TFCC) foveal tear. This study investigated to identify how much radiographic UPV occurs due to a TFCC foveal tear, which may be misdiagnosed as an ulnar impaction syndrome (UIS). MATERIALS AND METHODS: One hundred forty patients who underwent arthroscopic transosseus TFCC foveal repair from March 2013 to March 2019 in our institution were enrolled in this study. Ulnar variances were measured in preoperative, postoperative 6 weeks, 1-year follow-up wrist posteroanterior (PA) radiograph, and power grip PA radiograph of the affected wrist and were compared with those of the same patient's unaffected wrist. RESULTS: In the neutral wrist PA radiograph, ulnar variance increased by 0.56 mm (p < 0.001) after TFCC foveal tear compared to the unaffected side. In the power grip view, ulnar variance also increased by 0.39 mm (p < 0.001) in the affected wrist. The preoperative ulnar positive variance was reduced after an arthroscopic transosseous TFCC foveal repair from 0.56 to 0 mm (p < 0.001). No significant statistical difference was observed between an Atzei class 2 and 3 TFCC tear (0.56 mm vs. 0.41 mm, p = 0.263). CONCLUSION: This study revealed that TFCC foveal tear induces 0.56 mm of radiologic UPV, which was successfully corrected after arthroscopic transosseous TFCC foveal repair. Therefore, UPV associated with TFCC foveal tear should not be misdiagnosed as an UIS. Also, when ulnar shortening osteotomy is planned in case of UIS combined with TFCC foveal tear, the amount of UPV induced by TFCC foveal tear should be considered to prevent over-shortening.

Influence of TFCC foveal tear on the location of lunate chondromalacia in ulnar impaction syndrome.

OBJECTIVE: The purpose of this study was to identify the location of lunate chondromalacia and to compare the difference in location according to presence or absence of triangular fibrocartilage complex (TFCC) foveal tear, which induces distal radioulnar joint (DRUJ) instability. METHODS: We performed a retrospective study of 97 patients (102 wrists) who were diagnosed with and treated for idiopathic ulnar impaction syndrome (UIS) between 2014 and 2018. Subjects were divided into two groups according to presence or absence of TFCC foveal tear with DRUJ instability. Group I had UIS without a TFCC foveal tear (52 wrists, mean age of 43.2 years), while Group II had UIS with a TFCC foveal tear (50 wrists, mean age of 45.3 years). There was no significant difference in age, sex, or duration of symptoms between the two groups. All patients underwent wrist MR Arthrography (MRA) in the same gantry, and all scanned coronal sections of the lunate were standardized into 10 slices, including the whole anteroposterior width of the lunate. Each slice was sequentially numbered from dorsal to volar side, and the location of chondromalacia was marked in each numbered section. Radiological parameters including ulnar variance and ulnolunate distance (ULD), which indicated the distance between the ulnar head and lunate, were measured in the wrist series. RESULTS: The most frequent location of lunate chondromalacia was slightly to the volar side of the lunate in both groups. Group I showed a higher frequency of chondromalacia in the volar side of the lunate. In Group II, chondromalacia was identified with high frequency not only on the volar side of the lunate but also on the dorsal side. In other words, Group II showed broader chondromalacia in the lunate. There was no significant difference in ulnar variance (Group I, 3.19 ± 1.42 mm; Group II, 2.76 mm ± 1.67 mm) or ulnolunate distance (Group I, 1.66 ± 0.94 mm; Group II, 2.05 mm ± 0.87 mm). The average ULD decreased during radial deviation but increased during ulnar deviation. CONCLUSION: This study showed that lunate chondromalacia associated with idiopathic ulnar impaction syndrome occurs more frequently on the volar side of the lunate. Also, TFCC foveal tear, which causes DRUJ instability, leads to broader lunate chondromalacia in idiopathic ulnar impaction syndrome. Therefore, further analysis of the pattern of lunate chondromalacia can provide a clue for DRUJ instability.

Computed tomography arthrography using a radial plane view for the detection of triangular fibrocartilage complex foveal tears.

PURPOSE: To classify triangular fibrocartilage complex (TFCC) foveal lesions on the basis of computed tomography (CT) arthrography using a radial plane view and to correlate the CT arthrography results with surgical findings. We also tested the interobserver and intra-observer reliability of the radial plane view. METHODS: A total of 33 patients with a suspected TFCC foveal tear who had undergone wrist CT arthrography and subsequent surgical exploration were enrolled. We classified the configurations of TFCC foveal lesions into 5 types on the basis of CT arthrography with the radial plane view in which the image slices rotate clockwise centered on the ulnar styloid process. Sensitivity, specificity, and positive predictive values were calculated for each type of foveal lesion in CT arthrography to detect foveal tears. We determined interobserver and intra-observer agreements using kappa statistics. We also compared accuracies with the radial plane views with those with the coronal plane views. RESULTS: Among the tear types on CT arthrography, type 3, a roundish defect at the fovea, and type 4, a large defect at the overall ulnar insertion, had high specificity and positive predictive value for the detection of foveal tears. Specificity and positive predictive values were 90% and 89% for type 3 and 100% and 100% for type 4, respectively, whereas sensitivity was 35% for type 3 and 22% for type 4. Interobserver and intra-observer agreement was substantial and almost perfect, respectively. The radial plane view identified foveal lesion of each palmar and dorsal radioulnar ligament separately, but accuracy results with the radial plane views were not statistically different from those with the coronal plane views. CONCLUSIONS: Computed tomography arthrography with a radial plane view exhibited enhanced specificity and positive predictive value when a type 3 or 4 lesion was identified in the detection of a TFCC foveal tear compared with historical controls. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.