Disruption Of Triangular Fibrocartilage Complex Research Articles

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.

Biomechanical Comparison of Open and Arthroscopic Transosseous Repair of Triangular Fibrocartilage Complex Foveal Tears: A Cadaveric Study

To biomechanically compare the stability between open repair and arthroscopic transosseous repair technique for reattachment of the foveal triangular fibrocartilage complex (TFCC). We also evaluated the feasibility of a new aiming device for the creation of 2 bone tunnels simultaneously during the arthroscopic technique. Six matched pairs of fresh-frozen forearm cadaver specimens were prepared for testing. Group I specimens were treated by open repair with suture anchor. Group II specimens were treated by arthroscopic transosseous suture with a new aiming device. Before and after disruption of the TFCC fovea and after its repair, dorsal and palmar translation of the ulna was measured in both groups in response to a load (3kg) applied in the palmar and then in the dorsal direction. The total translation of the ulna was calculated as the sum of the mean dorsal and palmar translations. The mean total ulnar translation before and after TFCC disruption, and after TFCC repair was 5.94 ± 2.16mm, 9.08 ± 2.64mm, and 6.04 ± 2.18mm, respectively. The specimens demonstrated a significant increase in the total translation of the ulna after disruption of the ulnar attachment of TFCC (P= .003), whereas a significant decrease was observed after TFCC foveal repair (P= .003). The median percentage of eliminated translation after TFCC repair was 64% and 172%, respectively, in groups I and II (P= .043). The athroscopic transosseous suture technique demonstrated superior repair efficacy to the open repair technique in terms of biomechanical strength. This cadaveric study also demonstrated the feasibility of a new aiming device. When making decisions about TFCC foveal repair, arthroscopic transosseous suture technique may provide better biomechanical strength than the open repair technique.

Fixing fractures of the ulnar styloid in distal radius fractures

The majority of distal radius fractures are associated with an ulnar styloid fracture [1-3]. There is solid evidence in the literature that this association may ultimately affect the clinical outcome causing instability, disability, and pain in the distal radioulnar joint (DRUJ) [2,4-7]. The main reasons for the worse outcome are: (1) DRUJ instability, (2) impingement with the triquetrum, and (3) Extensor Carpi Ulnaris (ECU) tenosynovitis. Because of its close association with the Triangular Fibrocartilage Complex (TFCC), fractures of the ulnar styloid might indicate possible TFCC disruption with subsequent DRUJ instability [4,8,9]. Studies on the clinical relevance of ulnar styloid fractures have produced conflicting results. However, when considering size and displacement of the fracture, May et al [2] found that, after distal radius fracture stabilization, a fracture through the base of the ulnar styloid that involves most part of the TFCC attachment and stays in a deviated more radial position (2 mm or more) indicates DRUJ instability. In an ulnar styloid fracture model, Shaw et al [4] found that K-wire fixation of the ulnar styloid fracture restored stability to the DRUJ regardless the integrity of other supporting structures. Bone fragments resulting from non-union could also provoke irritation and pain [5,10] due to impingement with the triquetrum [11]. Twenty-six percent of ulnar styloid fractures develop non-union [12]. From those, just a few becomes symptomatic [5]. If the DRUJ is stable, simple removal of the fragment usually solves the problem [5,11]. Extensor carpi ulnaris tendon impingement caused by malalignment of a fibrous nonunion may also be responsible for a poor clinical outcome. [13,14]. This condition is rarely found after a distal radius fracture and it is successfully treated with excision of the bony prominence and reconstruction of the floor of the sixth compartment. Hence, fixation of a small sized ulnar styloid in the acute setting of a distal radius fracture is probably unnecessary. As the results of treatment of chronic instability of DRUJ following a distal radius fracture are more unpredictable [4], it is advisable to take all measures in the acute setting to prevent this complication. Therefore, fixation of the ulnar styloid is indicated when there are large sized fragments that persist deviated after stabilization of the radius or when the distal radioulnar joint is grossly unstable. Immobilization with a sugar tong splint for four weeks or until proper healing is necessary when the surgeon chooses not to fix a reduced ulnar styloid large fragment that is acceptably reduced.

Suture-Button Construct for Interosseous Ligament Reconstruction in Longitudinal Radioulnar Dissociations: A Biomechanical Study

Longitudinal radioulnar dissociation is a triad of injuries consisting of distal radioulnar joint disruption, interosseous ligament complex (IOLC) tear, and radial head fracture. This renders the forearm longitudinally unstable, resulting in proximal migration of the radius and ulnar-sided wrist degeneration. We hypothesized that reconstruction of the central band of the IOLC in cadaver forearms using a Mini-TightRope suture-button construct would restore native forearm stability. We implanted 8 fresh-frozen cadaver arms with steel beads into the distal radius and ulna, mounted them on an MTS machine, and cyclically loaded them from 13 N distraction to 130 N compression. Bead motion was recorded fluoroscopically and analyzed using Image-Pro Express software. We measured distal ulnar forces using strain gauge transducers. Longitudinal radioulnar dissociation injuries were created by radial head excision and complete IOLC and triangular fibrocartilage complex disruption. At each stage, arms were tested with and without a radial head implant. We reconstructed the central band of the IOLC using a Mini-TightRope and tightened until the distal radioulnar joint was reduced fluoroscopically. We used multiple-comparison analysis of variance with Tukey's Honestly Significant Difference test for statistical analysis. The intact arms had an average radioulnar axial displacement of 0.7 ± 0.8 mm and distal ulnar impaction force of 16.7 ± 11.1 N (per 100 N of axial load on the forearm). After destabilization, the radioulnar displacement increased to 10.7 ± 3.9 mm (p < .001) and ulnar load increased 312%, to an average of 52.2 ± 25.7 N (p < .001). After IOLC reconstruction, average displacement decreased to 2.2 ± 0.9 mm with a distal ulnar load of 19.05 ± 13.5 N (not significantly different from intact arms). In this cadaveric study, Mini-TightRope IOLC reconstruction with or without a radial head prosthesis significantly reduced distal ulnar impaction forces to that of the native forearm, while limiting radioulnar displacement to near-anatomic levels.

Evaluation of chronic wrist pain. Arthroscopy superior to arthrography: comparison in 39 patients.

39 patients with chronic wrist pain underwent arthrography and arthroscopy to reveal disruptions of the triangular fibrocartilage complex (TFCC) and/or interosseous ligaments. TFCC disruption was diagnosed arthroscopically in 15 cases of which arthrography revealed the disruption in only 7. In 3 other patients, arthrography showed rupture of the TFCC: however, arthroscopy showed no defects. Rupture of an interosseous ligament was diagnosed arthroscopically in 6 patients in all of whom it was also revealed by arthrography. In 6 other patients, arthrography showed disruption of an interosseous ligament not verified by arthroscopy. We conclude that arthroscopy is superior to arthrography for diagnosing chronic wrist pain.