Structural topography of the interosseous membrane of the human forearm.

The aim of this study was to evaluate the morphology of the six different parts of the interosseous membrane (IOM) in 11 human cadaver forearms, including the distal oblique bundle (DOB), the distal accessory band (DAB), the central band (CB), the proximal accessory band (PAB), the dorsal oblique accessory cord (DOAC), and the proximal oblique cord (POC). Hematoxylin-eosin and Elastica van Gieson stained slices were used to investigate the tissue morphology. The DOB and DOAC were absent in one IOM and the POB in two IOMs, respectively. The CB and DAB were longer than all other structures except for each other. The DOAC was longer than the DOB. The DAB, CB, and PAB, were broader than the DOB, DOAC, and POC. No significant differences were observed regarding structure thickness. All structures were found to consist of densely packed parallel collagen fiber arrangement. The DOB and POC had a higher amount of elastic fibers in the fascicular collagen tissue than the other structures. Elastic fibers were more often equally distributed throughout the structures than condensed epifascicular or at the insertion into bone. The tight parallel collagen composition within the different structures reflects the central stabilizing role of the IOM in the forearm. The higher amount of elastic fibers within the DOB and POC can be attributed to their location close to the distal and proximal radioulnar joints, respectively. Here elastic fibers allow adaption to forearm rotation, whereas the structures of the central part of IOM have less elasticity reflecting the predominant stabilizing function.

Digitalization of the IOM: A comprehensive cadaveric study for obtaining three-dimensional models and morphological properties of the forearm's interosseous membrane.

State-of-the-art of preoperative planning for forearm orthopaedic surgeries is currently limited to simple bone procedures. The increasing interest of clinicians for more comprehensive analysis of complex pathologies often requires dynamic models, able to include the soft tissue influence into the preoperative process. Previous studies have shown that the interosseous membrane (IOM) influences forearm motion and stability, but due to the lack of morphological and biomechanical data, existing simulation models of the IOM are either too simple or clinically unreliable. This work aims to address this problematic by generating 3D morphological and tensile properties of the individual IOM structures. First, micro- and standard-CT acquisitions were performed on five fresh-frozen annotated cadaveric forearms for the generation of 3D models of the radius, ulna and each of the individual ligaments of the IOM. Afterwards, novel 3D methods were developed for the measurement of common morphological features, which were validated against established optical ex-vivo measurements. Finally, we investigated the individual tensile properties of each IOM ligament. The generated 3D morphological features can provide the basis for the future development of functional planning simulation of the forearm.

The Effect of Distal Radius Fracture Location on Distal Radioulnar Joint Stability: A Cadaveric Study.

PURPOSE: To investigate whether the location of distal radius osteotomy/shortening relative to the radial insertion of the distal interosseous membrane (DIOM) is correlated with distal radioulnar joint (DRUJ) instability. We hypothesized that distal radius osteotomy and shortening proximal to the DIOM insertion would result in increased DRUJ instability because of induced laxity in the DIOM. METHODS: Osteotomies of the distal radius were performed proximal and distal to the DIOM insertion in 14 fresh-frozen cadaveric specimens. Using a volar plate, 5 conditions were tested: anatomical radius alignment; 2- and 4-mm shortening at the proximal osteotomy site; and 2- and 4-mm shortening at the distal osteotomy site. Basilar ulnar styloid osteotomy was performed to simulate triangular fibrocartilage complex (TFCC) detachment-specimens were tested with the ulnar styloid detached and the ulnar styloid fixed (to restore normal anatomy). The DRUJ stability was quantified using dorsal-volar displacement of the radius in response to 20 N of force using a force-displacement probe in neutral, pronation, and supination. Posttesting specimen dissections assessed DIOM and distal oblique bundle (DOB) anatomy. The DRUJ stability in each experimental condition was compared with a multifactor repeated measures analysis of variance with the specimen treated as the repeated factor. RESULTS: There were no significant differences in dorsal-volar translation of the radius (ie, DRUJ stability) between radial osteotomy/shortening proximal and distal to the DIOM insertion, regardless of forearm rotational position or magnitude of shortening. Five (36%) of the 14 specimens had a DOB present. There was a significant increase in DRUJ instability in the setting of TFCC detachment (via basilar ulnar styloid osteotomy). CONCLUSIONS: No difference in DRUJ stability was observed between distal radius osteotomy/shortening proximal and distal to the DIOM radial insertion, regardless of forearm rotation, magnitude of shortening, and/or TFCC detachment. CLINICAL RELEVANCE: Distal radius osteotomy and shortening did not affect DRUJ stability regardless of location relative to the DIOM insertion.

Interosseous Membrane Reconstruction Utilizing Flexor Digitorum Superficialis Autograft.

Interosseous membrane (IOM) deficiency results in longitudinal radioulnar instability, and may result in proximal radial migration, increased radiocapitellar contact, limitations in forearm rotation, ulnocarpal instability, and ulna-sided pain. A number of reconstruction methods have been posited-however, few have been implemented in vivo. We describe a 2-bundle method of IOM reconstruction, utilizing flexor digitorum superficialis autograft. This technique has the benefits of utilizing a locally available and robust autograft with minimal donor-site morbidity, obviating the concerns associated with synthetic grafts or bone-patella tendon-bone constructs. It also replicates the nonisometric nature of the native IOM. We also present long-term results of a patient who underwent IOM reconstruction utilizing this method, following a cadaveric feasibility study.