Topographical measurement of the attachments of the central band of the interosseous membrane on interosseous crests of the radius and ulna

Background: To suggest a reasonable isometric point based on the anatomical consistency of interosseous membrane (IOM) attachment in association with topographic characteristics of the interosseous crest, the footprints of the central band (CB) of the IOM on the radial and ulnar interosseous crests (RIC and UIC) were measured.Methods: We measured the distance from the CB footprints from each apex of both interosseous crests in 14 cadavers and the angles between the forearm axis of rotation (AOR) and the distal slopes of the RIC and UIC in 33 volunteers. Results: The CB footprints lay on the downslope of both interosseous crests with its upper margin on average 3-mm proximal from the RIC's apex consistently in the radial length, showing normality (p>0.05), and on average 16-mm distal from the UIC's apex on the ulna without satisfying normality (p<0.05). The average angle between the UIC's distal slope and the AOR was 1.3°, and the RIC's distal slope to the AOR was 14.0°, satisfying the normality tests (p>0.05), and there was no side-to-side difference in both forearms (p<0.05).Conclusions: The CB attached to the downslope just distal to the RIC's apex constrains the radius to the UIC that coincides with the AOR of the forearm circumduction, maintaining itself both isometrically and isotonically.

Distal-Ulna Stump Stability: The Role of Distal Interosseous Membrane: Myth or Reality? Anatomical Research

Background Distal-ulna stump (DUS) instability often occurs when performing a distal radioulnar joint (DRUJ) arthroplasty. Recent studies suggest that the distal interosseous membrane (DIOM) reinforces the triangular fibrocartilage complex, providing additional stability to the DRUJ. The aim of this study was to determine whether the DIOM stabilizes the ulnar stump. Methods Twenty fresh-frozen random forearms were dissected. The presence of a distal oblique bundle (DOB) was recorded and measured. The radius was fixed to a vise and the ulna kept free. The DRUJ was fixed with a lag screw. A bone slice was removed by transverse ulna osteotomies 10 and 15 mm proximal to the DRUJ. A 10-N force was applied to the ulna in dorsal and volar directions. Displacements were measured. The DIOM was then transected, and maneuvers and measurements were repeated and compared. Results A distinct distal membrane was present in 70% and a cord-like DOB in 30%. The mean length was 29 mm. Its origin was proximal to the sigmoid notch; its insertion was on the distal third of the ulna, at its lateral border. This attachment is comprised between 39 and 48 mm proximal to the ulnocarpal joint. Initial displacements averaged 22 mm dorsally and 13 mm volarly. After DIOM transection, ulnar translocation increased to 31 mm dorsally and 19 mm volarly. Conclusion In DRUJ arthroplasties, the DIOM does not appear to be a stabilizer of the DUS beneath a useful threshold. Its retaining effect occurs only after an initial 22-mm dorsal displacement, which we consider not clinically admissible. Therefore, in DRUJ arthroplasties, some augmentation might be advisable.

Contribution of a distal radioulnar joint stabilizer on forearm stability: A modeling study

Instability of the forearm is a complex problem that leads to pain and limited motions. Up to this time, no universal consensus has yet been reached as regards the optimal treatment for forearm instability. In some cases, conservative treatments are recommended for forearm instability injuries. However, quantitative studies on the conservative treatment of forearm instability are lacking. The present study developed a finite element model of the forearm to investigate the contribution of the distal radioulnar joint stabilizer on forearm stability. The stabilizer was designed to provide stability between the radius and ulna. The forearm model with and without the stabilizer was tested using the pure transverse separation and radial pull test for the different ligament sectioned models. The percentage contribution of the stabilizer and ligament structures resisting the load on the forearm was estimated. For the transverse stability of the forearm, the central band resisted approximately 50% of the total transverse load. In the longitudinal instability, the interosseous membrane resisted approximately 70% of the axial load. With the stabilizer, models showed that the stabilizer provided the transverse stability and resisted almost 1/4 of the total transverse load in the ligament sectioned models. The stabilizer provided transverse stability and reduced the loading on the ligaments. We suggested that a stabilizer can be applied in the conservative management of patients who do not have the gross longitudinal instability with the interosseous membrane and the triangular fibrocartilage complex disruption.

Coexistence of two accessory flexor pollicis longus heads or coexistence of two-headed flexor pollicis longus with an unrecognized anatomical structure?

The flexor pollicis longus (FPL) is located in the anterior compartment of the forearm. It is morphologically variable in both point of origin and insertion. An additional head of the FPL can lead to anterior interosseous syndrome. This report presents a morphological variation of the FPL (additional head in proximal attachment and bifurcated tendinous insertion in distal attachment) and an unrecognized structure that has not so far been described in the literature. This structure originates in six heads (attached to the FPL or interosseous membrane) that merge together, and inserts on to the FPL. All the variations noted have clinical significance, ranging from potential nerve compression to prevention of tendon rupture.

Surgical Treatment of a Symptomatic Diaphyseal Tibiofibular Synostosis in a Professional Rugby Player: A Case Report and Literature Review

Context: Diaphyseal tibiofibular synostosis (DTS) is a rare pathology with unknown origin especially occurring in intensive sport athletes. No therapeutic guideline has been well established in the literature. Case Presentation: A rare case of DTS in a 26-year-old professional rugby player has been described. A 5-month exhaustive conservative treatment including physiotherapy and oral medication has been achieved but failed. Management and Outcomes: Following the conservative treatment failure, the DTS has been widely removed including the adjacent interosseous membrane, and the patient could return to competition at the same level after 5 months of convalescence. No recurrence has been revealed at a 35-month follow-up at least. Conclusion: In accordance with the literature data and even if the pathophysiology remains obscure, resection of DTS seems to be the adapted treatment to allow and to reduce professional athletes’ recovery time at the same sport level. The resection including a part of the tibiofibular interosseous membrane could avoid the occurrence of recurrence. Conservative treatment should be reserved for senior patients with a low sport activity.

Distal interosseous membrane of the forearm: anatomy, biomechanics, diagnostics

Relevance. Recent studies show that even with damage to the structures of the triangular fibrocartilaginous complex (primary stabilizer), instability of the distal ray-elbow joint does not develop in some cases. Studies carried out by a number of authors prove that the distal interosseous membrane of the forearm can influence the stability of the joint and be a secondary stabilizer for it. Aim of the study. To study the variability in the structure of the distal interosseous membrane of the forearm using anatomical material and determine the effect of the distal interosseous membrane on the stability of the distal ray-elbow joint. Using ultrasound to determine the variability of the structure of the distal interosseous membrane of the forearm. Materials and methods. Material for our study was 10 pairs of anatomical specimens of the upper extremities. The functional viability was assessed by passive rotation of the anatomical material of the forearm. Changes in the tension of the distal interosseous membrane, its additional formations and the capsule of the distal ray-elbow joint were observed. Ultrasound was chosen as an instrumental method for visualizing the distal interosseous membrane of the forearm and its structures. In the course of this work, 30 volunteers of both sexes and different ages were examined. The study was carried out: maximum pronation (position of the sensor back) and maximum supination (position of the sensor palmar). Results. In the course of the anatomical study, we determined that in 6 pairs of anatomical material, the distal interosseous membrane is a thin transparent connective tissue structure. No additional formations in the form of thickening were found. In 4 pairs of preparations, which amounted to 40% of the total amount in the distal interosseous membrane, there were additional formations in the form of thickening of the membrane this is the distal oblique bundle and the distal ray-the ulnar tract. During the functional study, it was revealed that during pronation of the forearm, the distal membrane and dorsal capsule are stretched, which in turn holds the head of the ulna in the sigmoid notch of the radius. After conducting ultrasound, we determined the variability in the structure of the distal interosseous membrane of the forearm. The distal oblique bundle is visualized as a linear hyperechoic formation. Of the 30 surveyed, this formation was identified in 13 women (92.8%) and 1 man (7.1%), which in percentage terms was 43%. Conclusion. After conducting anatomical examination, we determined the variability in the structure of the distal interosseous membrane of the forearm in the form of the presence of thickenings the distal oblique bundle and the distal ray-ulnar tract, and determined the effect of these structures on the stability of the distal ray-elbow joint. An ultrasound scan also identified the features in the structure of the distal interosseous membrane in the form of hyperechoic formation.