The anatomic detail of the interosseous membrane was studied by dissection of 20 preserved cadaveric specimens. The interosseous membrane was found to be a complex structure consisting of a central ...band, accessory bands, a proximal interosseous band, and membranous portions. The central band, a stout ligamentous structure, was found in all specimens. Fibers of the central band originate on the radius and are oriented distal and ulnar an average of 21
0 to the longitudinal axis of the ulna. Accessory bands were of less substance than the central band but were present in all specimens. The number of accessory bands ranged from 1 to 5. The proximal interosseous band is located on the dorsal surface only, and its fibers run counter to the central band. It shares a point of origin with the central band on the radius. This structure was present in 17 of 20 specimens. Since the central band was the most dominant and consistent structure, we chose to analyze the strain in the central band in 6 preserved specimens. Maximum strain in the central band of the intact specimen occurs in neutral forearm rotation. Once the radial head is removed, the percent strain universally increases throughout the arc of forearm rotation and peak strain shifts to pronation.
The biomechanical function of the interosseous membrane of the forearm was examined in 12 fresh cadaver forearms. The strain in the central band of the interosseous membrane was found to be greatest ...in full pronation and was significantly increased with excision of the radial head. The proximal/distal location of the lunate fossa of the radius with respect to the ulna was measured and was found to be most distal in supination and most proximal in pronation, in both the intact specimen and after excision of the radial head. Serial sectioning of the interosseous membrane and the triangular fibrocartilage complex (TFCC) demon-strated that both the central band and the TFCC are important to the axial stability of the forearm. Reconstruction of the central band, using a graft based upon the flexor carpi radialis, was performed in all 12 specimens after the interosseous membrane and the TFCC were sectioned. It was successful in preventing complete migration of the radius to the capitellum, but it was not capable of completely restoring the longitudinal stability of the forearm. Central band reconstruction as described here has not been performed in the clinical setting and is not advocated for clinical application at this time.
Malunion of the metacarpal or phalanx can result in significant functional impairment of the hand. Ideally, thissituation is best dealt with by prevention. When faced with a malunion, surgical ...correction can be a formidable task. However, anatomic alignment can be restored by osteotomy. This paper will explore the techniques of osteotomy, as they apply to a variety of metacarpal and phalangeal malunions. The key to optimal outcome is preoperative planning, meticulous surgical technique, rigid internal fixation and early postoperative range of motion.
Magnetic resonance imaging of seven fresh human cadaveric specimens was used to evaluate the integrity of the triangular fibrocartilage complex of the wrist. A variety of imaging parameters were ...systematically investigated, including T1-weighted images with and without contrast, long repetition times, short echo time images, and T2-weighted sequences. A variety of imaging planes were also evaluated. Wrist arthrography, dissection, and frozen coronal sections were done to substantiate our interpretations of the magnetic resonance images. T2-weighted images in the coronal plane proved to be of the greatest diagnostic value because the synovial fluid of the joint spaces serves as an excellent endogenous contrast agent. Long repetition time, short echo time sequences could be simultaneously obtained with T2-weighted sequences with the use of a multi-echo pulse sequence to provide an excellent diagnostic package in the future. On the basis of our investigation, the triangular fibrocartilage complex can be consistently and accurately evaluated with magnetic resonance imaging. As magnetic resonance imaging technology improves, wrist probes and suitable magnets should become available that will make the evaluation of triangular fibrocartilage complex abnormalities with magnetic resonance imaging clinically useful.
Symptomatic nonunion of the ulnar styloid is an uncommon problem that is usually best treated by simple excision of the ulnar styloid fragment. Two types of nonunion of the ulnar styloid are ...described here on an anatomic basis, and their treatment differs. Type 1 is defined as a nonunion associated with a stable distal radioulnar joint. Type 2 is defined as a nonunion associated with subluxation of the distal radioulnar joint. The postoperative follow-up period for the two types ranged from 4 months to 13 years, with a mean of 5 years 2 months. Eleven type 1 wrists were treated with excision of the fragment, and all patients had satisfactory relief of pain. Nine type 2 wrists required restoration of the anatomy of the triangular fibrocartilage complex. Three of these had large fragments that were treated by open reduction and internal fixation. All three patients were completely relieved of their discomfort. Six other patients underwent excision of the fragment and repair of the triangular fibrocartilage complex to the distal ulna. This group had four excellent, one good, and one fair result. If the distal radioulnar joint is stable on presentation or if its stability is restored, then long-term relief of pain from ulnar styloid nonunion is achieved by treatment of the nonunion.
