Radioulnar Ligaments Research Articles

Effect of decrease in radial inclination of distal radius fractures on distal radioulnar joint stability: a biomechanical study.

We investigated the relationship between the radial inclination of the distal radius and distal radioulnar joint stability. Six fresh-frozen upper extremities were used. Radial inclination was decreased by 10° and 20° and increased by 10° from the original radial inclination. Distal radioulnar joint stiffness was assessed with an intact radioulnar ligament and after partial and then complete sectioning of the radioulnar ligament. Radial angulation deformities significantly increased distal radioulnar joint stiffness when the radioulnar ligament is totally or partially attached to the ulnar fovea. After complete sectioning of the radioulnar ligament, distal radioulnar joint stiffness decreased significantly; additional radial angulation deformity slightly increased distal radioulnar joint stiffness, but the distal radioulnar joint never recovered to the original stiffness. Based on the results, radial angulation deformities of the distal radius should be corrected within 10° when the radioulnar ligament is intact, to reduce the risk of symptomatic distal radioulnar joint instability.

Point-of-care wrist ultrasonography in trauma patients with ulnar-sided pain and instability

ObjectiveWe evaluated the effectiveness of point-of-care wrist ultrasonography compared with 3T-magnetic resonance imaging (MRI) for diagnosing triangular fibrocartilage complex (TFCC) injuries in trauma patients with ulnar-sided pain and instability. Moreover, we assessed the inter-observer variability between an emergency physician and a musculoskeletal radiology fellow. Material and methodsA prospective cross-sectional study was conducted in an emergency department; patients with ulnar-sided sprain and instability were recruited. An emergency physician and a musculoskeletal radiology fellow independently evaluated the TFC, meniscal homologue, volar and dorsal distal radioulnar ligaments, and extensor carpi ulnaris using point-of-care ultrasonography. Findings were classified as normal, partial rupture, or complete rupture. Wrist 3T-MRI was used as the reference standard. We compared the diagnostic values for point-of-care ultrasonography obtained by both reviewers using DeLong's test. Intra-class correlation coefficients (ICCs) were calculated for agreement between each reviewer and the reference standard, and directly between the two reviewers. ResultsSixty-five patients were enrolled. Point-of-care wrist ultrasonography showed acceptable sensitivity (97.2–99.1%), specificity (96.8–97.3%), and accuracy (96.9–97.9%); these diagnostic performance values did not differ significantly between reviewers (p=0.58–0.98). Agreement between each reviewer and the reference standard was excellent (emergency physician, ICC=0.964; musculoskeletal radiology fellow, ICC=0.976), as was the inter-observer agreement (ICC=0.968). ConclusionPoint-of-care wrist ultrasonography is as precise as MRI for detecting TFCC injuries, and can be used for immediate diagnosis and further preoperative imaging. Moreover, it may shorten the interval from emergency department admission to surgical intervention while reducing costs.

Transposition of extensor retinaculum to reconstruct distal radioulnar joint dorsal ligament for treatment of distal radioulnar joint dorsal instability

Objective To evaluate the efficacy of distal radioulnar joint (DRUJ) dorsal ligament reconstruction using extensor retinaculum transposition with triagular fibrocartilage complex (TFCC) repair and dorsal capsuloplasty for chronic DRUJ dorsal instability. Methods From October 2007 to July 2016, data of 18 patients (11 men and 7 women with a mean age of 37.4 years) were retrospectively analyzed who underwent DRUJ dorsal ligament reconstruction with extensor retinaculum transposition, DRUJ dorsal capsuloplasty, and TFCC repair for DRUJ dorsal instability. The tissue flap of extensor retinaculum was fixed at the ulnar edge of distal radius by two micro anchors after TFCC repair and dorsal capsuloplasty of the DRUJ capsule. X-ray examination of wrist was performed for all the patients after operation to identify the reduction of DRUJ. The wrist range of flexion and extension, the forearm range of rotation, and the grip strength of hand were measured. Modified Mayo wrist scores, DASH scores and visual analogue scale (VAS) were used to evaluate the function and pain of wrist and upper extremity. Results 18 patients were followed up for 12-70 months with an average period of 34 months. The stability of the DRUJ was restored in 16 patients. The other 2 cases wore long arm splint for 6 weeks after operation due to the residual instability of the DRUJ, after that the instability of DURJ were improved to grade I. The flexion and extension of wrist, the rotation of forearm were improved, but there were no significant difference comparing to those of pre-operation. The VAS, modified Mayo and DASH scores, grip strength of hand were significantly improved from preoperative 4.2±1.1, 67.4±11.2, 51.3±14.2, 16.3±3.7 kg to postoperative 0.2±0.5, 83.9±11.6, 15.9±3.2, 24.9±6.4 kg at the latest follow-up. Conclusion Extensor retinaculum transposition with TFCC repair and DRUJ dorsal capsuloplasty can effectively relieve pain and recovery stability of DRUJ, which was an effective method for chronic DRUJ dorsal instability. Key words: Carpal joints; Joint instability; Ligaments; Reconstructive surgical procedures

Modification of the use of the extensor retinaculum for reducible distal radioulnar joint instability: technique and results.

Different surgical techniques have been described for chronic distal radioulnar joint instability: they are often complicated, quite invasive and may not be recommended for bidirectional instability. We describe a procedure using a radial-based extensor retinaculum strip and a capsular plication. This is a simple technique and less invasive than ‘anatomic’ radioulnar ligament reconstructions. We report the results of 38 patients (38 wrists) who we treated. After a minimum of 8 months we quantified the outcomes of the patients objectively by assessing ranges of motion, grip strength and clinical assessment of stability, and subjectively using questionnaires. Overall, 36 out of 38 patients were stable after surgery. The operated forearm and wrist had approximately 3° less range of motion in all planes and 3 kgf less grip strength compared with the unoperated side. The median Mayo modified wrist score was 90; the median visual analogue scale score was 2. This surgical technique appears to successfully treat patients with chronic reducible distal radioulnar joint instability. Anatomic reconstruction of both radioulnar ligaments is not always necessary.Level of evidence: IV

A biomechanical study on effect of deep radioulnar ligaments on the distal radioulnar joint rotatory stability repaired by bone suture anchors

To discuss the role of the bone suture anchors for repair of avulsed deep radioulnar ligaments in maintaining the rotatory stability of the distal radioulnar joint. Nine upper limbs specimens were selected from fresh adult cadavers to make wrist joint-bone capsular ligaments complex specimen. All the specimens were tested under conditions of intact (normal group), deep radioulnar ligaments injury (injury group), and deep radioulnar ligaments injury repaired with anchoring (repair group). The internal and external rotation torque values were recorded in 45° wrist extension, neutral position, and 45° wrist flexion by AG-IS series MS biomechanical testing system. The statistic software was used to compare difference in rotation torque between groups. In 45° wrist extension, neutral position, and 45° wrist flexion, the internal rotation torque values in normal group were (0.83±0.33), (0.86±0.34), and (0.36±0.30) N·m respectively; the external rotation torque values were (0.86±0.38), (0.44±0.22), and (0.25±0.21) N·m respectively. The internal rotation torque values in injury group were (0.18±0.17), (0.22±0.17), and (0.16±0.15) N·m respectively; the external rotation torque values were (0.27±0.26), (0.13±0.17), and (0.04±0.04) N·m respectively. The internal rotation torque values in repair group were (0.79±0.34), (0.73±0.33), and (0.41±0.23) N·m respectively; the external rotation torque values were (0.80±0.39), (0.41±0.22), (0.41±0.40) N·m respectively. In 45° wrist extension, neutral position, and 45° wrist flexion, the internal and external rotation torque values in injury group were significantly lower than those in normal group and repair group ( P<0.05), but no significant difference was found between repair group and normal group ( P>0.05). The deep radioulnar ligaments are important structure for maintaining rotatory stability of distal radioulnar joint. Bone anchoring of the avulsed deep radioulnar ligaments to the ulna fovea is critically important in reconstructing function anatomy of the distal radioulnar joint.

Topographical Anatomy of the Distal Ulna Attachment of the Radioulnar Ligament

The deep component of the distal radioulnar ligament provides translational stability and rotational guidance to the forearm. However, controversy exists regarding the importance of this structure as well as the nature of its attachment to the distal ulna. We aimed to evaluate the topographic anatomy of the distal ulna attachment of both the superficial and the deep components of the radioulnar ligament and to assess the relationship between its internal and its external morphometry. Thirteen human distal ulnae attached by ulnar part of the distal radioulnar ligament were scanned using micro-computed tomography and reconstructed in 3 dimensions. In addition, the distal radioulnar ligaments were examined under polarized light microscopy to determine the histological characteristics of collagen contained within the ligaments. The deep limbs have broad marginal insertions at the fovea, whereas the superficial limbs have a circular and condensed insertion to the ulnar styloid. The center of the deep limb was separated from the base of the ulnar styloid by a mean of 2.0 ± 0.76 mm, and this distance was positively correlated with the width of the ulnar styloid. The mean distance between the center of the ulnar head and the center of the fovea was 2.4 ± 0.58 mm. The proportion of collagen type I was lower in the deep limb than in the superficial limb. This new observation of the footprint of the radioulnar ligament in the distal ulna indicates that the deep limb may serve as an internal capsular ligament of the distal radioulnar joint, whereas the superficial limb as the external ligament. Knowledge of the topographic anatomy of the radioulnar ligament's attachment to the distal ulna may provide a better understanding of distal radioulnar ligament-related pathologies.

High-resolution 3T Magnetic Resonance Imaging of the Triangular Fibrocartilage Complex in Chinese Wrists: Correlation with Cross-sectional Anatomy.

Background:The injury of the triangular fibrocartilage complex (TFCC) is a common cause of ulnar-sided wrist pain. The aim of this study was to investigate if the high-resolution 3T magnetic resonance imaging (MRI) could demonstrate the detailed complex anatomy of TFCC in Chinese.Methods:Fourteen Chinese cadaveric wrists (from four men and three women; age range at death from 30 to 60 years; mean age at 46 years) and forty healthy Chinese wrists (from 20 healthy volunteers, male/female: 10/10; age range from 21 to 53 years with a mean age of 32 years) in Beijing Jishuitan Hospital from March 2014 to March 2016 were included in this study. All cadavers and volunteers had magnetic resonance (MR) examination of the wrist with coronal T1-weighted and proton density-weighted imaging with fat suppression in three planes, respectively. MR arthrography (MRAr) was performed on one of the cadaveric wrists. Subsequently, all 14 cadaveric wrists were sliced into 2 mm thick slab with band saw (six in coronal plane, four in sagittal plane, and four in axial plane). The MRI features of normal TFCC were analyzed in these specimens and forty healthy wrists.Results:Triangular fibrocartilage, the ulnar collateral ligament, and the meniscal homolog could be best observed on images in coronal plane. The palmar and dorsal radioulnar ligaments were best evaluated in transverse plane. The ulnotriquetral and ulnolunate ligaments were best visualized in sagittal plane. The latter two structures and the volar and dorsal capsules were better demonstrated on MRAr.Conclusion:High-resolution 3T MRI is capable to show the detailed complex anatomy of the TFCC and can provide valuable information for the clinical diagnosis in Chinese.

Arthroscopic assisted tendon reconstruction for triangular fibrocartilage complex irreparable tears.

IV.

Classification of ulnar triangular fibrocartilage complex tears. A treatment algorithm for Palmer type IB tears.

II.

Arthroscopically Assisted Transosseous Foveal Repair of Triangular Fibrocartilage Complex

The radioulnar ligament of the triangular fibrocartilage complex (TFCC), especially the deep fibers inserted at the ulnar fovea, is the key component for the distal radioulnar joint (DRUJ) stability. Traumatic injuries to the TFCC foveal insertion would cause DRUJ instability. Traditionally, arthroscopic techniques of the TFCC repair are suturing the ulnar-sided disruption peripherally to the dorsal or ulnar capsule instead of suturing the TFCC to the fovea and thus fail to restore the DRUJ stability if the TFCC is detached from the fovea. Recently, some arthroscopic foveal repair techniques have been reported using a suture anchor or transosseous sutures to address the foveal tear. This technical note describes an arthroscopic transosseous technique to reattach the foveal-disrupted TFCC. A 1.6-mm small osseous tunnel is created on the radial border of the fovea and 4 sutures are passed into the tunnel by using a 16-gauge needle. The TFCC could be sutured arthroscopically with these 4 sutures and be compressed against the fovea. Our technique provides not only a good suture construct for TFCC foveal reattachment but also an anatomic contact surface between the torn TFCC and its foveal footprint for healing. We recommend this technique as an alternative for repairing TFCC foveal tear.

Ulnar Styloid Base Fractures Cause Distal Radioulnar Joint Instability in a Cadaveric Model.

The deep portion of the distal radioulnar ligaments (DRUL) inserts on the ulnar fovea and is the most important stabilizer of the distal radioulnar joint (DRUJ). Ulnar styloid base fractures that include the ulnar fovea may cause DRUJ instability. DRUJ stability in pronosupination was evaluated in 12 fresh-frozen upper extremities (4 female) aged 52 to 68 years (mean: 58.8 years) using a custom fixture, which allowed free rotation of the radius around the fixed ulna. Optical motion capture was used to record rotation of the radius with respect to the ulna. Each specimen was subjected to 3 N m of torque in both supination and pronation under 4 conditions: intact, ulnar styloid osteotomy with disruption of the foveal insertion of the DRUL, ulnar styloid fixation, and DRUL transection. Group differences were compared using a 1-way repeated-measures analysis of variance and Tukey multiple comparison post hoc tests. When compared with the intact condition, both ulnar styloid osteotomy and DRUL transection significantly increased mean pronation (by 9.40° and 15.21°, respectively) and supination (by 9.05° and 17.42°, respectively) of the forearm. Screw fixation only significantly reduced pronation compared with osteotomy (by 2.62°). Screw fixation did not significantly affect supination. Ulnar styloid fractures that disrupt the fovea cause instability of the DRUJ in pronation and supination under 3 N m of torque in a cadaveric model. Screw fixation of ulnar styloid base fractures achieves anatomic reduction; however, it only partially returns rotational stability acutely to the DRUJ and only during pronation.

Instability and Arthritis of the Distal Radioulnar Joint: A Critical Analysis Review.

Arthritis and instability represent 2 of the most common pathological processes affecting the distal radioulnar joint (DRUJ). These conditions can present in isolation or as components of a multifactorial process. Nonoperative treatment is indicated for most acute injuries to the DRUJ. The joint should be immobilized in a position of stability to allow for ligament healing. Likewise, early arthritis responds favorably to rest, immobilization, corticosteroids, and nonsteroidal anti-inflammatory drugs (NSAIDs). When DRUJ instability is refractory to nonoperative measures, native ligament repair is the preferable method of treatment. When this method is not possible, anatomical reconstruction of the distal radioulnar ligaments should be performed. For advanced DRUJ arthritis Darrach resection should be reserved for the elderly, low-demand patient. The Sauve-Kapandji procedure allows for arthrodesis of the DRUJ while maintaining forearm rotation and a stable base for the ulnar carpus. DRUJ hemiarthroplasty procedures have been associated with favorable preliminary results. These implants attempt to reproduce native biomechanics and may be used in lieu of or as a salvage procedure after resection arthroplasty. DRUJ arthroplasty should be used as a salvage procedure.

Medium- to long-term outcomes of anatomical reconstruction of the radioulnar ligament to the ulnar fovea.

IV.

Topographic Anatomy of Distal Radioulnar Ligament Insertion in the Distal Ulna

Background: Insertion of the distal radioulnar ligaments onto the distal ulna is critical to provide translational stability and rotational guidance of the forearm. However, the topographic anatomy of the footprints of these ligaments and their relationships with morphometry of the distal ulna remain unclear. Purpose: We provide a detailed description of the anatomy and the relationships described above in a cadaveric study. Methods: Seventeen human distal ulnas attached by both the superficial and deep limbs of the distal radioulnar ligaments were scanned using micro-computed tomography and reconstructed 3 dimensionally. Results: The deep limbs have narrow marginal insertions just behind the pole of the distal ulna, but the width of the footprint was larger at the fovea than at the peripheral lesion. The superficial limb footprints were the circular and condensed shape. The center of the deep limb was radially distant from the base of the ulnar styloid by a mean of 2.00 ± 0.72 mm, and the distance was positively correlated with the width of the ulnar styloid ( r = .517, P = .030). The mean distance between the center of the ulnar head and the center of the fovea was 2.34 ± 0.62 mm. Conclusions: The deep limb has a narrow marginal insertion just behind the pole of the distal ulna, suggesting its role as the capsular ligament. The center of the fovea is located more radially from the ulnar styloid base. The data provide a better understanding of distal radioulnar ligament-related pathology to perform distal ulnar fixation or ligament repair to recover distal radioulnar joint stability.

High-Resolution 3T MR Imaging of the Triangular Fibrocartilage Complex.

This study is intended as a review of 3Tesla (T) magnetic resonance (MR) imaging of the triangular fibrocartilage complex (TFCC). The recent advances in MR imaging, which includes high field strength magnets, multi-channel coils, and isotropic 3-dimensional (3D) sequences have enabled the visualization of precise TFCC anatomy with high spatial and contrast resolution. In addition to the routine wrist protocol, there are specific techniques used to optimize 3T imaging of the wrist; including driven equilibrium sequence (DRIVE), parallel imaging, and 3D imaging. The coil choice for 3T imaging of the wrist depends on a number of variables, and the proper coil design selection is critical for high-resolution wrist imaging with high signal and contrast-to-noise ratio. The TFCC is a complex structure and is composed of the articular disc (disc proper), the triangular ligament, the dorsal and volar radioulnar ligaments, the meniscus homologue, the ulnar collateral ligament (UCL), the extensor carpi ulnaris (ECU) tendon sheath, and the ulnolunate and ulnotriquetral ligaments. The Palmer classification categorizes TFCC lesions as traumatic (type 1) or degenerative (type 2). In this review article, we present clinical high-resolution MR images of normal TFCC anatomy and TFCC injuries with this classification system.

Role of the Interosseous Membrane in Preventing Distal Radioulnar Gapping.

Background Damage to the interosseous membrane (IOM) can alter load transmission between the radius and ulna and decrease their axial stability. Less is known about the effect of IOM sectioning on the transverse stability between the radius and ulna. Purpose The purpose of this study was to quantify the radioulnar gapping at the distal radioulnar joint (DRUJ) during forearm rotation when the IOM was experimentally sectioned while maintaining the integrity of the distal radioulnar ligaments. Methods In 12 fresh-frozen cadaver forearms tested in a combined wrist-forearm simulator, the increase in gap between the radius and ulna, at the level of the DRUJ, was determined during cyclic forearm rotation following IOM sectioning. Results IOM sectioning caused a significant increase in dorsal gapping at the DRUJ by 2.1 mm in supination and 0.6 mm in pronation. It also caused an increase in palmar gapping by 1.3 mm in supination and 0.5 mm in pronation. Conclusion This experiment has shown that the IOM has an important role in stabilizing the DRUJ, especially in supination, and that IOM sectioning caused greater loads on the palmar and dorsal radioulnar ligaments. Since DRUJ instability is primarily treated by fixing the laxity at the dorsal radioulnar ligament (DRUL) and palmar radioulnar ligament (PRUL), untreated IOM damage could permit additional injury and instability to the radioulnar ligaments or their reconstruction. Clinical Relevance Reconstruction of a torn IOM should be considered in the presence of persistent DRUJ instability following DRUJ reconstruction.

Volar Central Portal in Wrist Arthroscopy.

Background Nowadays, the wrist is not limited to a dorsal visualization; the joint can be thought of as a "box," which can be visualized from almost every perspective. The purpose of this study was to describe a new volar central portal for the wrist, following three principles: a single incision that allows access to both the radiocarpal and midcarpal joints, centered on the lunate, with the volar structures at risk protected not only by retractors, but also by tendons. Description of Technique The incision begins in the distal wrist crease and extended 1.5 cm proximally up to the proximal wrist crease, following the axis of the third intermetacarpal space. The flexor superficialis tendons are identified and retracted toward the radial side. Next, the fourth and fifth flexor digitorum profundus tendons are retracted toward the ulnar side, while the third and second tendons are retracted toward the radial side. The volar central midcarpal portal is performed under direct vision just over the anterior horn of the lunate through the Poirier space. The volar central radiocarpal portal is created under the lunate through the interval between the ulnocarpal ligaments and the short radioulnar ligament. Methods An anatomical study was performed on 14 cadaver specimens. Two data were recorded: iatrogenic injuries of the structures at risk and the distances to the structures at risk. Results The median (interquartile range [IQR]) distances from the volar central radiocarpal portal to the median nerve, palmar cutaneous branch of the median nerve, and ulnar neurovascular bundle were 10.5 (7.8-15.0), 18.5 (15.8-20.3), and 7.0 (5.0-10.5) mm, respectively. The median (IQR) distances from the volar central midcarpal portal to the median nerve, palmar cutaneous branch of the median nerve, and ulnar neurovascular bundle were 7.0 (4.8-10.3), 16.0 (14.8-19.0), and 4.5 (3.8-9.0) mm, respectively. No iatrogenic injuries were observed. Conclusion The volar central portal is reproducible and safe. The risk of iatrogenic injury is low. The capsule is pierced through one of its thinner portions, and both the radiocarpal and midcarpal joints can be inspected through one single incision.

Histological assessment of the triangular fibrocartilage complex.

The morphological structure of the seven components of triangular fibrocartilage complexes of 11 cadaver wrists of elderly people was assessed microscopically, after staining with Hematoxylin-Eosin and Elastica van Gieson. The articular disc consisted of tight interlaced fibrocartilage without blood vessels except in its ulnar part. Volar and dorsal radioulnar ligaments showed densely parallel collagen bundles. The subsheath of the extensor carpi ulnaris muscle, the ulnotriquetral and ulnolunate ligament showed mainly mixed tight and loose parallel tissue. The ulnolunate ligament contained tighter parallel collagen bundles and clearly less elastic fibres than the ulnotriquetral ligament. The ulnocarpal meniscoid had an irregular morphological composition and loose connective tissue predominated. The structure of the articular disc indicates a buffering function. The tight structure of radioulnar and ulnolunate ligaments reflects a central stabilizing role, whereas the ulnotriquetral ligament and ulnocarpal meniscoid have less stabilizing functions.

Stabilizing Effect of Ulnar Shortening Procedure for DRUJ Instability

Ulnar shortening is widely indicated for ulnocarpal abutment syndrome with positive-variance wrist. It also stabilizes the distal radioulnar joint (DRUJ) because of tightening effect on the triangular fibrocartilage complex (TFCC), as long as either the dorsal or palmar portion of the radioulnar ligament (RUL) is attached to the ulnar fovea. In clinical practice, it is very important to check the condition of the RUL through DRUJ arthroscopy, when the ulnar shortening was indicated for DRUJ instability cases. We retrospectively analyzed our case series.

How does wrist position affect the length of the distal radioulnar ligament: a three-dimensional image study in vivo?

This study was designed to investigate the length changes of the distal radioulnar ligament at different wrist positions and to determine the effect of hyperextension on the distal radioulnar ligament and to find out the most vulnerable position where the distal radioulnar ligament rupture and foveal avulsion. We obtained computed tomography scans of the wrists for 12 volunteers including two groups: hyperextension group and hyperextension with maximal rotation group. The images were reconstructed to the three-dimensional bone structures with customized software. The four portions of the distal radioulnar ligament were measured and analyzed statistically. No significant differences were noted in the lengths of the each portion of the distal radioulnar ligament among neutral position, wrist hyperextension, and hyper-radial extension. From neutral position to hyperextension with maximal pronation, the lengths of the palmar superficial radioulnar ligament (psRU) and dorsal deep radioulnar ligament (ddRU) decreased significantly, whereas the dorsal superficial radioulnar ligaments (dsRU) and palmar deep radioulnar ligament (pdRU) increased significantly. From neutral position to hyperextension with maximal supination, the lengths of the pdRU and dsRU ligaments decreased significantly, and the lengths of psRU and ddRU ligaments changed little. The factor of hyperextension has little effect on the length of the distal radioulnar ligament and the distal radioulnar ligament may be under great tension at the position of hyperextension with maximal pronation. These findings can provide more information to understand the pathomechanics of the triangular fibrocartilage complex injury caused by a fall on the outstretched hand and can provide information relevant to the distal radioulnar ligament restoration.