Meniscus Homologue Research Articles

Quantitative analysis of triangular fibrocartilage complex injury by 3.0T MR 3D VIBE and T2 mapping techniques.

To evaluate triangular fibrocartilage complex (TFCC) injury based on quantitative analysis of fibrocartilage by 3.0T MR 3D VIBE and T2 mapping techniques. In this study, 25 patients with TFCC (15 patients with unilateral injury and 10 patients with bilateral injury) and 30 healthy subjects were enrolled. All 55 participants underwent bilateral wrist joint routine plain scan + enhanced scan, 3D VIBE and T2 mapping sequence scan. The 2 hands were divided into the dominant group and the non-dominant hand group. Pseudo-color images of T2 mapping were obtained through the post-processing workstation. Except for the meniscus homologue, there were statistical differences in the overall mean T2 value of all other regions between the injured group and the healthy group (P < .001). The T2 value of each region in the injury group was statistically different in the pairwise comparison (all P < .02). There was no statistical difference in the overall mean T2 value between the dominant hand group and the non-dominant hand group. 3.0T MR 3D VIBE and T2 mapping techniques are helpful for the evaluation of TFCC injury and the quantitative analysis of fibrocartilage. The parameters can reflect molecular changes of fibrocartilage injury, and T2 values are not affected by dominant hand, age and gender.

The triangular fibrocartilage complex in the human wrist: A scoping review toward uniform and clinically relevant terminology.

The aim of this scoping review was to assess the composition, terminology, and anatomy of the triangular fibrocartilage complex (TFCC) of the wrist and propose unambiguous terminology regarding the individual components. The review was conducted according to the methodological framework by Arksey and O'Malley (International Journal of Social Research Methodology, 2005, 8, 19–32). Electronic databases were searched from inception until September 1, 2021 for original anatomical studies, using MeSH terms and keywords on terminology and anatomy of TFCC components. Studies using gross dissections or macro‐ or microscopic histology were included. Animal studies, fetal studies and studies with unknown disease status, were excluded. A total of 24 studies were included. The articular disc, the radioulnar ligaments, the meniscus homologue and the extensor carpi ulnaris tendon (sub)sheath were unanimously classified as TFCC components. One study did not include the ulnolunate and ulnotriquetral ligaments and only one study did include the ligamentum subcruentum. The largest disagreement existed regarding the inclusion of the ulnar collateral ligament. Terminological ambiguity was seen in “triangular fibrocartilage,” “triangular ligament,” “igamentum subcruentum,” and the “proximal and distal lamina.” Anatomical ambiguity existed especially regarding the radioulnar ligaments, the ulnar attachments of the TFCC and the ulnar collateral ligament. Definitions of the individual TFCC components are redundant, ambiguous, and ill‐defined and therefore subject to different interpretations. In order to preclude confusion, consensus regarding terminology is recommended. We proposed a concise definition of the healthy TFCC that can be used as a starting point for future studies and current clinical practice.

Ulnar Wrist Pain Revisited: Ultrasound Diagnosis and Guided Injection for Triangular Fibrocartilage Complex Injuries.

The triangular fibrocartilage complex (TFCC) serves as the major stabilizer of the wrist. Its injuries can result from trauma or degeneration, both of which are strongly correlated with the loading stress on the ulnar shaft and carpal joints. The TFCC is made of the articular disc, meniscus homologue, ulnocarpal ligament, radioulnar ligament, ulnotriquetral ligament, ulnolunate ligament, and subsheath of the extensor carpi ulnaris tendon. Because of its complexity, it is challenging to confirm the exact component affected in TFCC injuries. The Palmer classification is widely used for investigation of TFCC lesions using magnetic resonance imaging. Recently, high-resolution ultrasound (US) has become more popular in diagnosing musculoskeletal disorders. However, the utility of US imaging in TFCC lesions is less common because its anatomy under US imaging is not described in the current literature. Accordingly, in this review, we aimed to propose a standard US scanning protocol for the TFCC, present relevant images for its pathologies, and illustrate appropriate US-guided injection techniques for their management.

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.

How I manage TFCC injuries

The TFCC consists of triangular fibrocartilage (TFC), meniscus homologue, ulnolunate ligament, ulnotriquetral ligament, radioulnar ligament, and sheath floor of the extensor carpi ulnaris (ECU). The TFCC functions as a stabilizer of the ulnocarpal and DRU joints, load distributor between ulna and ulnar carpus and introduces smooth forearm rotation. The TFCC is a hammock-like shape supporting and surrounding the ulnar carpus, with the strong and nearly vertical anchor to the ulnar fovea, i.e. the RUL. During forearm rotation, the radius, the carpus and distal surface of the TFCC rotate over the ulnar head, thus simple twisting of the RUL occurs at its foveal attachment. The main stabilizer of this tiny joint is the proximal component of the TFCC, the radioulnar ligament (RUL). Central attaching fibers of the RUL at the fovea indicate isometric pattern during forearm rotation, while eccentric fibers at the fovea and base of the styloid indicate changes in length, dorsal indicates longer length in pronation, while palmar indicates longer in supination. When the RUL is torn, instability of the DRUJ occurs. The greater the tear of the RUL be, the greater instability of the DRUJ indicates. When the RUL is ruptured at the fovea, the RUL must be introduced into the central lesion of the fovea of the ulna. Classical Palmer 1B peripheral lesion also demonstrates moderate DRUJ instability, because this lesion is close to the RUL. Other traumatic lesions on the TFCC, such as Palmer 1A and 1D tear, did not indicate DRUJ instability. Diagnosis of DRUJ instability due to TFCC tear is achieved by physical examination, such as DRUJ ballottement test, arthrogram, MRI and arthroscopy. Image diagnosis is useful, however arthroscopy is a gold standard for diagnosis as well as treatment of the TFCC lesions. DRUJ arthroscopy, recently introduced arthroscopic technique, provides direct visualization of fovea lesion, where the RUL attaches. Treatments of TFCC lesions are depending on the tear site. Palmer 1B lesion is easily treated by arthroscopic capsular repair. Debridement is useful for palmer 1A or 1D tear. We also prefer to shorten the ulna, when there were degenerative changes on the TFC (Palmer Class 2) or with ulnar positive variance. Treatment options for DRUJ instability due to TFCC foveal avulsion are arthroscopic and open repair of the TFCC to the fovea for acute or sub-acute cases and reconstruction of the TFCC using ECU half-slip tendon or PL tendon for chronic TFCC injuries. Ulnar shortening procedure can be useful for partial avulsion of the RUL either dorsal or palmar, but not for complete avulsion of the TFCC at the fovea. Arthroscopic partial resection of the TFCC can no longer indicated for unstable DRUJ, because it does not introduce stabilization of the DRUJ.

Anatomy and Clinical Relevance of the Ulnocarpal Ligament

Anatomy and Clinical Relevance of the Ulnocarpal Ligament

Meniscus and discus lesions of triangular fibrocartilage complex (TFCC): treatment by laser-assisted wrist arthroscopy

Meniscus and disc lesions in the triangular fibrocartilage complex (TFCC) are generally caused by falling accidents with pronated, hyperextended wrists, or by distraction injuries that pull the ulnar side of the wrist out of place. Characteristic clinical signs are swelling and pain in the distal radioulnar joint (DRUJ) and a 'clicking' noise in the meniscus lesion. If untreated, loss of mobility and grip strength as well as progressive arthritic changes ensue. We investigated in this study the laser-assisted arthroscopic debridement of the central TFCC and meniscus to compare the advantages and disadvantages of such treatment to conventional arthroscopic debridement. Seventy-two patients underwent laser-assisted arthroscopic debridement of traumatic TFCC tears (meniscus and disc). Patients with TFCC tears that were associated with fractures, significant bone or neurovascular pathology or DRUJ instability were excluded from the study. The mean age was 32.4 years; 28 female and 51 male patients were included in the study. The mean follow up was 25.6 months. First of all, we evaluated the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. We then applied the range of motion of the hand (ROM) as second variable during statistical analysis to identify outcome. There were no complications after surgery. No instabilities or dislocations of the DRUJ were noted. The postoperative DASH score indicated that the laser-assisted arthroscopic repair of traumatic peripheral TFCC tears resulted in a very good functional outcome. All patients with isolated meniscus homologue tears were without pain after the operation. At final follow up, the ROM was equal to or greater than that of the contralateral side. We have demonstrated that the TFCC laser debridement technique is easy and safe to perform. The outcome was excellent with less pain and good ROM. In particular, the laser technique enabled a good intra-articular haemostasis and allowed an exact tear debridement.

The anatomy of the ulnocarpal complex

The ulnocarpal complex (triangular fibrocartilage complex; TFCC) represents an intricate system of structures which secures motion guidance, stability and pressure transmission in the ulnocarpal compartment of the wrist joint. Anatomically, this complex consists of the ulnocarpal disc (triangular disc), palmar and dorsal radioulnar ligaments, ulnolunate, ulnotriquetral and ulnocapitate ligaments, ulnocarpal meniscus homologue, ulnar recess (prestyloid recess), ulnocarpal collateral ligament and tendon sheath of the extensor carpi ulnaris. The distal radioulnar joint and the interosseous membrane of the forearm, which lie close together, also belong functionally to the ulnocarpal complex. Together with the proximal radioulnar joint, they permit rotational movements of the hand (pronation and supination). This review highlights all components of the ulnocarpal complex systematically. Distinctive characteristics involving size, as well as variations, are listed, and their functional meaning analyzed. The accumulated knowledge serves as a basis for possible interventions both at the ulnocarpal complex and the distal radioulnar joint.

High-resolution MR imaging of triangular fibrocartilage complex (TFCC): comparison of microscopy coils and a conventional small surface coil

To compare MR images of the triangular fibrocartilage complex (TFCC) using microscopy coils with those using a conventional surface coil qualitatively and quantitatively. Proton density-weighted images and T2*-weighted images of the TFCC from ten normal volunteers were obtained with a conventional surface coil (C4 coil; 80 mm in diameter), a 47-mm microscopy surface coil and a 23-mm microscopy surface coil) at 1.5 T. Qualitative image analysis of MR images with three coils was performed by two radiologists who assigned one of five numerical scores (0, nonvisualization; 1, poor; 2, average; 3, good; 4, excellent) for five TFCC components, which were disc proper, triangular ligament, meniscus homologue, ulnotriquetral and ulnolunate ligament. Quantitative analysis included the signal-to-noise ratio (S/N) of the disc proper of TFCC, the lunate cartilage, the lunate bone and the contrast-noise-ratio (C/N) between articular cartilage and disc proper or bone marrow were measured. All structures show higher scores qualitatively on MR with microscopy coils than those with a C4 coil, and the difference was significant with the exception of the ulnolunate ligament. MR with microscopy coils showed significantly higher S/N values than those with a conventional surface coil (P<0.05 to P<0.001). T2*-weighted images using microscopy coils showed significantly higher cartilage-disc proper C/N and cartilage-bone marrow C/N (P<0.01 to P<0.001). On proton density-weighted images, the C/N between cartilage and disc proper with two microscopy coils was significantly higher (P<0.01) than that with a conventional coil. High-resolution MR images of the normal wrist using microscopy coils were superior to those using a conventional surface coil qualitatively and quantitatively. High-resolution MR imaging with a microscopy coil would be a promising method to diagnose TFCC lesions.

Histological anatomy of the triangular fibrocartilage complex of the human wrist

The triangular fibrocartilage complex (TFCC) was studied in serial histological sections of the human wrist to reveal its three-dimensional fine structure. The TFCC consisted of a fibrocartilaginous disc proper and other fibrous components. Three-dimensionally, the distal portion of the TFCC had a hammock-like contour that partially surrounded the carpus; while the proximal ligamentous portion corresponding to the radioulnar ligament connected the radius to the ulna. The radioulnar ligament originated at the ulna from both the fovea and the basistyloid. The fibres first gathered and then bifurcated palmarly and dorsally, enclosing and partially coalescing with the proximal side of the disc before inserting around the distal rim of the sigmoid notch of the radius. The meniscus homologue, which corresponded to the ulnar internal wall of the wrist joint, was derived from a loose synovial fold adapting to the stresses from radioulnar deviation. The distal side of the disc consisted of a dense population of chondrocytes in a collagen matrix, while the proximal side was rather rich in fibres directed radioulnarly. Inside the TFCC were loose connective tissues. The histological arrangement of the TFCC is compatible with its function of supporting the carpus, stabilizing the joints and allowing smooth motion of the wrist.

An anatomic study of the ligamentous structure of the triangular fibrocartilage complex

An anatomic study of the ligamentous structures of the triangular fibrocartilage complex and their attachments on the ulnar styloid was performed using 27 embalmed cadaver wrists. The dorsal and palmar distal radioulnar ligaments of the triangular fibrocartilage complex in each specimen contained a superficial and a deep portion. The deep portion of both ligaments inserted on the fovea of the ulna. The superficial portion of both ligaments surrounded the articular disc uniting at the ulnar-most portion of the articular disc. The tissue that is between the ulnar aspect of the superficial ligament (and integrated on its periphery) and the ulnar capsule is defined as the meniscus homologue. Anatomic variations in the meniscus homologue and the prestyloid recess (the cavity adjacent to the ulnar styloid) were seen in 1 of 3 ways; the narrow opening type in 74% of specimens, the wide opening type in 11%, and the no opening type in 15%. The ulnotriquetral ligament inserted on the palmar-radial aspect of the base of the ulnar styloid and the ulnolunate ligament inserted on the palmar border of the articular disc.

Morphology and distribution of nerve endings in the human triangular fibrocartilage complex

We studied the morphology and distribution of nerve endings in the human triangular fibrocartilage complex using both silver staining and immunohistochemical staining using a protein specific to nerve fibres. Free nerve endings were found in the ulnar side of the triangular fibrocartilage complex, especially in the ulnar collateral ligament, meniscus homologue and the adjacent collagen fibre area of the peripheral part of the ulnar side of the articular disc. Meissner's and Krause's corpuscles were observed in the ulnar collateral ligament and meniscus homologue. The fact that free nerve endings were observed in the meniscus homologue and adjacent collagen fibre area of the peripheral part of the ulnar side of the articular disc suggests that this disc may be a source of wrist pain. The presence of nerve end bulbs in the triangular fibrocartilage complex also suggests a possible role for corpuscles as mechanoreceptors.

SOFT-TISSUE ANATOMY AND RELATIONSHIPS ABOUT THE DISTAL ULNA

The author investigates the complex anatomic relationship between the ulnar head and adjacent osseous structures (radius and carpus). Special attention is directed to the orientation and shape of the articular surfaces the constraining effects of specific membranes and ligaments (radio-ulnar and ulnocarpal), the shock-absorbing function of the triangular fibrocartilage, and the dynamic action of specific muscles (pronator quadratus and extensor carpi ulnaris) The anatomy of other nonstabilizing structures (meniscus homologue and prestyloid recess) is also discussed.

Triangular fibrocartilage complex: normal appearance on coronal three-dimensional gradient-recalled-echo MR images.

To evaluate the usefulness of three-dimensional gradient-recalled-echo (GRE) sequences in demonstration of the triangular fibrocartilage complex (TFCC). Appearance of the TFCC in wrists of 11 cadavers, 17 patients, and six volunteers at three-dimensional GRE magnetic resonance (MR) imaging was evaluated and compared with that at dissection. MR appearance of the TFCC was similar for all wrists. Volar and dorsal radioulnar ligaments were identified. The TFCC had two types of attachments to the ulna: The more common consisted of two striated attachments, one to the tip and the other to the base of the styloid; the less common consisted of a broad-based striated attachment along the styloid. MR appearance of the ulnotriquetral and ulnolunate ligaments and meniscus homologue varied but correlated with observations at dissection. The three-dimensional GRE sequence consistently demonstrated most TFCC components. Dissection helped confirm MR-demonstrable variability in the ulnar aspect of the TFCC.

The triangular fibrocartilage complex of the wrist—Anatomy and function

The anatomy and function of the triangular fibrocartilage complex (TFCC) of the wrist was studied through anatomic dissections and biomechanical testing of 61 specimens. The TFCC was found to be a homogenous structure composed of, but not dissectable into, the articular disc, the dorsal and volar radioulnar ligaments, the meniscus homologue, the ulnar collateral ligament, and the sheath of the extensor carpi ulnaris. The TFCC was found to be perforated in 53% of specimens dissected, and all of the wrists with a demonstrable perforation showed evidence of damage or erosion of the cartilage of the lunate and/or distal ulna. Biomechanical studies suggest that the TFCC functions both as a cushion for the ulnar carpus and as a major stabilizer of the distal radioulnar joint. Perforations of the TFCC can result in the ulna-lunate abutment and cartilage erosion. Since excision of the TFCC may lead to ulnolunate abutment, chronic wrist pain, and/or instability of the distal radioulnar joint, it is not recommended.