The Distal Oblique Bundle in the Distal Forearm: From Anatomical Features to Clinical Implementation

Background and objective The distal oblique bundle (DOB) is nowadays recognized as the thickest component of the distal interosseous membrane (DIOM). It is neither thought to be a clear-cut ligament, and nor does it follow the typical configuration of the rest of the DIOM. It is not always present and some studies have raised disputes about its prevalence and a few anatomical features. In this study, we aimed to provide data on the prevalence and anatomical features of the DOB, which are of great importance at this early stage of research into the topic. Our findings have been correlated with current knowledge and are expected to contribute to clinical implementation. Materials and methods Twenty-eight fresh-frozen forearms were utilized for measurements. Specifically, mean length, width, distance from the middle of the bundle's insertion to the ulna to the tip of the styloid process of the ulna, as well as the distance from the midpoint of its insertion to the radius to the tip of the radiuses' styloid process were calculated. The prevalence was described with a cutoff thickness point of 0.5 mm. Early results based on three cases of DOB reconstruction with the "Riggenbach" technique due to distal radioulnar joint (DRUJ) instability were documented. Results Eleven DOBs were reported out of the 28 specimens, suggesting a prevalence of 39.3%. The mean thickness was 0.88 mm (range: 0.6-1.3 mm), the mean width was 5.22 mm (range: 2.2-8.4 mm), and the mean length was 25.68 mm (range: 22.7-29.2 mm). Proximally, the mean distance from the bundle's ulnar insertion to the tip of the styloid process of the ulna was 51.02 mm (range: 45.5-55.6 mm) while distally, the mean distance from the bundle's insertion to the radius to the tip of the styloid process of the radius was 34.5 mm (range: 31.3-37.7 mm). After a follow-up of at least six months, improvement was evident in all measured areas in the three patients who underwent surgery. Additionally, they reported satisfaction and accomplishment of their preoperative goals. Conclusions Discrepancies in measurements in some anatomic features between studies are probably due to variations in specimen types, measurement methods, and sites. Efforts must continue to be made on a more extensive scale and in a more standardized manner for more factual results and conclusions. "Reconstruction-recreation" or "original construction-creation" procedures yield promising results in a fast, simple, and less invasive manner than traditional methods of DRUJ stabilization.