A. Lee Osterman
DEFINITION
The triangular fibrocartilage complex (TFCC) is a complex anatomic structure located at the ulnar side of the wrist. It has several important biomechanical functions:
Extends the gliding surface of the radiocarpal joint
Cushions and stabilizes the ulnar carpus
Stabilizes the distal radioulnar joint (DRUJ)
Disorders of the TFCC are responsible for the ulnar-sided wrist symptoms of pain, weakness, and instability that affect the patient's function.
The diagnosis and treatment of these injuries to the TFCC will restore stability, resulting in pain relief and a generally good prognosis for functional return.
ANATOMY
The TFCC is a cartilaginous and ligamentous structure interposed between the ulnar carpus and the distal ulna (FIG 1A). It arises from the distal aspect of the sigmoid notch of the radius and inserts into the base of the ulnar styloid.17
The TFCC attaches to the ulnar carpus via the ulnocarpal ligament complex (ulnolunate, ulnotriquetral, and ulnar collateral ligament) (FIG 1B).
The radioulnar ligaments stabilize the DRUJ, limiting rotation as well as axial migration.7
The dorsal and volar radioulnar ligaments are fibrous thickenings within the substance of the TFCC.
As a result of this anatomic configuration, they function as a unit rather than as independent ligaments.
The central, horizontal portion of the TFCC is the thinnest portion, composed of interwoven obliquely oriented sheets of collagen fibers for the resistance of multidirectional stress.
The vascularity of the TFCC has been carefully studied.3 The TFCC receives its blood supply from the ulnar artery through its radiocarpal branches and the dorsal and palmar branches of the anterior interosseous artery. These vessels supply the TFCC in a radial fashion (see Bednar et al3 for a good image of TFCC vascularity).
Histologic sections demonstrate that these vessels penetrate only the peripheral 10% to 40% of the TFCC. The central section and radial attachment are avascular.
This vascular anatomy supports the concept that peripheral injuries can heal if injured and treated appropriately, whereas tears of the central portion do not heal if sutured and are usually débrided.
Biomechanics
The TFCC has several important biomechanical functions: it transmits 20% of an axially applied load from the ulnar carpus to the distal ulna; it is the major stabilizer of the DRUJ; and it is a stabilizer of the ulna.1,6,18,19
The amount of the load transferred to the distal ulna varies with ulnar variance. A greater amount is transferred in positive ulnar variance than negative.
This results in a corresponding decreased thickness of the central portion of the TFCC in ulnar-positive wrists.
There is a variable load placed on the TFCC with forearm rotation. Supination causes a negative ulnar variance due to the proximal migration of the ulna. This is reversed with pronation as the ulna moves distally, causing it to become ulnar-positive.
The ulnar head also moves within the sigmoid notch in a dorsal direction with pronation and a volar direction with supination.
The dorsal and volar radioulnar ligaments, which form the peripheral portion of the TFCC, serve as major stabilizers to translation at the DRUJ during forearm rotation.
PATHOGENESIS
Traumatic injuries of the TFCC result from either the application of an extension, pronation force to the axially loaded wrist or a distraction force to the ulnar aspect of the wrist.
FIG 1 • A. Anatomic coronal section demonstrating the triangular fibrocartilage (TFC) and its relation to the lunate (L), triquetrum (T), distal ulna (U), and radius (R). B. Triangular fibrocartilage complex.
This will most commonly occur with a fall on the outstretched hand or a resisted torque force.
The lesions are more common with ulnar-positive and neutral patients and are frequently found in patients with fractures of the distal radius.
Several authors have examined the incidence of intracarpal soft tissue injuries associated with distal radial fractures.
Geissler et al8 studied 60 patients, finding a TFCC injury in 26 (43%).
In Lindau et al's series of 51 patients,13 43 had a TFCC injury (84%): 24 had a peripheral tear, 10 had a central perforation, and 9 had a combined central and peripheral tear.
In a study of 180 wrist joints in 100 cadavers ranging in age from fetuses to 94 years, Mikic14 found that degeneration of the TFCC begins in the third decade of life.
This degeneration increases in frequency and severity as people age.
After the fifth decade of life, 100% of TFCCs appear abnormal.
However, these age-related TFCC lesions are often asymptomatic.6
NATURAL HISTORY
The classification system described by Palmer16 is the most useful for describing TFCC injuries, dividing them into traumatic and degenerative.
Traumatic lesions are classified according to the location of the tear within the TFCC. The traumatic class has been designated by Palmer as class 1, with subclasses of A, B, C, and D assigned to anatomic lesions within the TFCC (FIG 2A).
A class 1A lesion represents a tear in the horizontal or central portion of the TFCC. The tear is 2 to 3 mm medial to the radial attachment of the cartilage. It is usually oriented from dorsal to volar.
A class 1B lesion represents an avulsion of the peripheral aspect of the TFCC from its insertion onto the distal ulna. This can occur either with a fracture of the ulnar styloid or as a pure avulsion from its bony attachment. This type of injury disrupts the stabilizing effect of the TFCC on the DRUJ, resulting in clinical instability.
A class 1C lesion represents an avulsion of the TFCC attachment to the ulnar carpus by disruption of the ulnocarpal ligaments. These lesions result in ulnar carpal instability with volar translocation of the carpus.
A class 1D lesion represents an avulsion of the TFCC from its radial attachment. Isolated disc tears should be differentiated from disruption of the dorsal and volar radioulnar ligaments. Such global TFCC injury will result in DRUJ instability.
Degenerative type 2 lesions are age-related, nontraumatic lesions to the TFCC, typically characterized by central perforations and positive ulnar variance.6,23
The natural history of such degenerative lesions, when and if they become symptomatic, is a progressive cascade of degenerative changes, as reflected in Palmer's type 2 classification (FIG 2B).
The deterioration proceeds from TFC wear through central perforation (type 2C) to lunatotriquetral ligament tear and arthritic changes of the lunate, triquetrum, and distal ulna (type 2D or E).
Treatment is based on the stage of involvement.
Degenerative and traumatic lesions can coexist, and injury can render a degenerative lesion symptomatic.
PATIENT HISTORY AND PHYSICAL FINDINGS
Symptoms consist of ulnar-sided wrist pain, frequently with clicking, that typically occurs after a fall.
The initial physical examination reveals swelling over the ulnar aspect of the wrist with inflammation of the tendon of the extensor carpi ulnaris.
Point tenderness is present over the TFCC and distal ulna. The more isolated the point of maximal tenderness, the more specific the diagnosis.
A fovea sign (point tenderness directly over the ulnar TFC origin) indicates a type 1A or IB TFC injury or an ulnar extrinsic injury type [1C]).
Ulnar deviation and axial loading of the wrist (TFCC compression test) will elicit a painful response and a click with forearm rotation.
The DRUJ must be assessed for instability. Instability is best assessed with the forearm in neutral rotation, but it is also checked in full supination and full pronation.
The examiner stabilizes the distal radius with one hand and applies a force to the distal ulna, moving it dorsal and volar, looking for increased motion or subluxation of the distal ulna relative to the radius and comparing it with the opposite uninjured wrist.
FIG 2 • A. Axial drawing looking at the radius platform and the TFCC. Dorsal is up and volar is down. Palmer classification for acute triangular fibrocartilage complex (TFCC) injuries. A class 1A lesion involves a tear in the central, horizontal portion of the TFCC. A class 1B lesion is a tear of the TFCC from the distal ulna with or without an ulnar styloid fracture. A class 1C lesion is a tear of the TFCC distal attachment to the lunate and triquetrum through the ulnolunate and ulnotriquetral ligaments. A class 1D lesion is a detachment of the TFCC from its insertion on to the radius at the distal sigmoid notch. B.Palmer classification for degenerative TFCC lesions, usually related to positive ulnar variance and ulnocarpal impaction syndrome. The degeneration occurs in a progressive cascade: types 2A and 2B, TFC wear; type 2C, fibrillated central TFC lesion; types 2D and 2E, arthritic chondral changes of the distal ulna and lunate and disruption of the lunatotriquetral ligament. (A: Modified From Palmer AK. Triangular fibrocartilage complex lesions: a classification. J Hand Surg Am 1989;14A:601.)
Significant instability can present as laxity of the distal ulna with a positive “piano key” sign and dorsal prominence of the distal ulna. This may be due to a significant tear or detachment of the dorsal or volar radioulnar ligaments.
A click produced by ulnar deviation and supination over the extensor carpi ulnaris (ECU) sheath at the distal ulna indicates ECU instability with subluxation out of its sixth extensor compartment.
A visual carpal supination deformity with ulnar prominence that can be passively corrected by a dorsally applied force to the pisiform indicates an ulnar extrinsic ligament tear.
TFCC injuries do not occur in isolation; they are often a component of a spectrum of injury to the ulnar side of the wrist. The examiner must therefore evaluate all of the commonly injured structures on the ulnar side of the wrist.
The lunatotriquetral joint must be assessed for instability due to a lunatotriquetral ligament tear. This would cause tenderness over the lunatotriquetral interval with a positive shuck test (painful click as the lunate and triquetrum slide abnormally).
Point tenderness over the triquetrum may signify a triquetral avulsion fracture.
An audible clunk and visual subluxation of the carpus that occur with active ulnar deviation suggest that a midcarpal instability is present.
Crepitus and pain over the pisotriquetral joint on the shear test may indicate pisotriquetral arthritis.
The other soft tissue structures around the ulnar wrist should be examined, including the ulnar nerve, the dorsal ulnar sensory nerve branch, and the ulnar artery.
Grip strength measurements using a Jamar dynamometer, while subjective, are helpful in quantitating patient effort and as a parameter to follow therapeutic progress.
IMAGING AND OTHER DIAGNOSTIC STUDIES
The diagnostic workup should include plain radiographs and a neutral rotation posteroanterior and lateral view.
This will allow assessment for fracture, ligament instability resulting in carpal malalignment, and ulnar variance. It is important to determine ulnar variance because it will influence treatment options (FIG 3A).
The DRUJ must also be examined radiographically to determine if subluxation, arthritis, or ulnar styloid abnormalities such as an acute or chronic nonunited fracture fragment are present.
MRI is useful in the diagnosis of TFCC tears, especially the class 1A and D lesions.9,11 T2-weighted images in the coronal plane are of the greatest diagnostic value (FIG 3B).
The TFCC has a homogenous low signal intensity. The synovial fluid of the joint appears as a bright image on T2 and will outline tears in the TFCC.
A gadolinium arthrogram enhances the visualization of TFCC tears.
The reported sensitivity and specificity of MRI in diagnosing injuries of the TFCC in the literature is variable.
Golimbu et al9 reported a 95% accuracy of MRI in the detection of TFCC tears. MRI findings were verified arthroscopically.
Schweitzer et al20 reported a sensitivity of 72%, a specificity of 95%, and an accuracy of 89%.
Arthroscopic findings were correlated with the MRI and clinical examination in a series of patients with TFC injuries reported by Bednar et al.2 The MRI sensitivity was 44% (the probability of a positive MRI when a TFCC lesion is present) and the specificity was 75% (the probability of a negative MRI when a TFCC lesion is absent). The clinical examination sensitivity was 95%. The MRI correlated with arthroscopic findings in 45% of the wrists studied.
Joshy et al11 reported on a series of patients with a clinical suspicion of a TFCC tear studied by MR arthrography and then wrist arthroscopy. The MR arthrography sensitivity was 74% and its specificity was 80%. They caution that negative results of MR arthrography in patients with clinical suspicion of TFCC tear should be interpreted with caution.
Wrist arthroscopy has recently become the criterion standard for both diagnosing and treating lesions of the TFCC.6
When compared to MRI and arthrography, arthroscopy most accurately determines the location of lesions and the size of tears and allows determination of whether a flap is unstable.
Wrist arthroscopy can determine the coexistence of other lesions such as tears within the lunotriquetral interosseous ligament, ECU subsheath, or chondral lesions.
FIG 3 • A. Positive ulnar variance is often associated with degenerative triangular fibrocartilage (TFC) tears and ulnocarpal impaction syndrome. The radiograph should be taken in neutral rotation. B. Coronal T2 MRI wrist image. High signal of the joint fluid outlines the low-signal substance of the TFC complex. Tears will show as high signal within the central region (arrow at right) or TFCC periphery. There is a normal clear area (arrow at left) at the insertion of the radial TFC into the medial articular cartilage of the radius.
DIFFERENTIAL DIAGNOSIS
ECU subluxation
Ulnar extrinsic ligament tear
DRUJ instability
Triquetral avulsion fracture
Lunatotriquetral ligament injury
Pisotriquetral arthritis
Ulnar artery thrombosis
Ulnar neuropathy at the canal of Guyon
Dorsal ulnar sensory neuritis
NONOPERATIVE MANAGEMENT
The initial treatment of acute TFCC injuries includes immobilization of the wrist and DRUJ.
The patient must be examined carefully to look for DRUJ instability or ECU subluxation.
If the radiographs are negative and instability is not present, then immobilization for 4 to 6 weeks is recommended to allow healing of the TFCC disruption.
A peripheral tear is expected to heal if the torn edges are held in close contact, due to the good vascularity of the periphery of the TFCC. Many central tears also become asymptomatic with immobilization even though there is no significant vascularity to the central portion.
After immobilization, a therapy program involving rangeof-motion exercises and gradual strengthening is initiated. Forceful grasp or torque is restricted for 8 weeks.
If there is ongoing synovitis, a well-placed cortisone shot can further help to quiet this inflammation.
Tears involving the ligamentous portion of the TFCC or those that heal with a flap of cartilage that impinges on the carpus or distal ulna will fail to respond to conservative treatment and will require operative intervention.
It is reasonable to wait 3 to 4 months before proceeding to surgical treatment.
Class 1B lesions without an ulnar styloid fracture and a stable DRUJ can be immobilized for 4 weeks in a cast. If an ulnar styloid fracture is present, closed reduction should be attempted. If adequate reduction is achieved, then cast immobilization is sufficient. If the styloid remains displaced, then open reduction and internal fixation is required.
SURGICAL MANAGEMENT
Patients who remain symptomatic after adequate immobilization should undergo further workup, including MRI with or without gadolinium.
The specific treatment for each traumatic class 1 lesion is determined by the type of tear found arthroscopically.
Arthroscopic treatment has become increasingly the method of choice for many traumatic lesions.
The treatment of traumatic radial detachment of the TFCC from the sigmoid notch of the distal radius is controversial. There appears to be no vascularity to this portion of the TFCC, so theoretically a reattached cartilage would not heal at this repair site. However, clinical experience with open repair of these tears has been positive.6,21 This may be attributed to vascular ingrowth from the bony radial insertion site that occurs with abrasion of the attachment site, stimulating the formation of new vessels.
If the radial tear includes disruption of one or both of the radioulnar ligaments, repair is required to prevent chronic DRUJ instability.
The algorithm for the treatment of degenerative type 2 tears proceeds from arthroscopy to ulnar-shortening osteotomy (see Chaps. HA-94 and HA-95).
Plain films should identify the ulnar variance, DRUJ alignment, abnormalities of the ulnar styloid, or the presence of arthritic changes. Positive ulnar variance has a strong association with degenerative tears.
Preoperative Planning
All physical examination findings and radiographic study results must be reviewed.
Examination under anesthesia is performed, including the tests discussed earlier, before positioning in the arthroscopy tower.
Positioning
Wrist arthroscopy requires distraction, and the wrist is positioned in the traction tower (FIG 4).
FIG 4 • Positioning for standard wrist arthroscopy. Distraction of the wrist using a wrist traction tower.
WRIST ARTHROSCOPY
Diagnostic wrist arthroscopy of the radiocarpal and midcarpal joints is completed and all pathology is identified.
Recognize the appearance of a normal TFC (TECH FIG 1).
The type of TFC injury is identified.
A trampoline test is positive when the surgeon's probe sinks into the TFCC rather than bouncing off it like a drumstick on a snare drum. Such loss of disc compliance is often seen with a peripheral tear.10However, laxity of the TFCC does not necessarily translate into DRUJ instability.
Loose bodies, if present, are removed.
Inflamed synovium is removed with a shaver or radiofrequency probe.
TECH FIG 1 • Normal arthroscopic view of the intact triangular fibrocartilage (TFC) with normal “trampoline” tension when probed.
ARTHROSCOPIC REPAIR OF PERIPHERAL TFC TEARS
Peripheral TFC tears are well vascularized and amenable to repair using arthroscopic techniques. A two-needle method similar to that employed for the repair of a knee meniscus is described here (TECH FIG 2A).
Visualize the tear through the 3–4 portal.
Initial arthroscopic evaluation may not reveal a tear of the TFCC periphery, but often synovitis and a thin scar will be seen along the periphery of the TFCC at the location of the tear (TECH FIG 2B).
A probe placed through the 6R portal will demonstrate loss of the normal trampoline effect of the TFCC, indicating a peripheral tear and loss of mechanical function of the TFCC (TECH FIG 2C).
Débride the edges of the tear and undersurface scarring with a shaver to create mobile edges with fresh areas for healing.
Adhesions may be present between the undersurface of the TFCC and the distal ulna. These must be released and the TFC mobilized sufficiently to allow advancement to reattach it and to restore proper tension.
After débridement, a 1-cm longitudinal incision is made extending the 6R portal.
Avoid injury to branches of the dorsal ulnar sensory nerve.
Open the sixth extensor compartment radially for 1 cm and retract the extensor carpi ulnaris ulnarly, providing access to its subsheath.
The repair includes the subsheath of the ECU compartment as this is intimately associated with the peripheral TFC.
Two needles are passed across the tear under arthroscopic vision (TECH FIG 2D).
A wire loop is passed through one needle to retrieve a 2-0 PDS suture, which is passed through the other needle.
This allows the placement of a horizontal mattress suture across the tear (author's preference) (TECH FIG 2E).
Alternatively, multiple simple vertical sutures placed at the periphery of the TFCC may approximate the torn edges and restore tension to the TFCC. The suture is tied either under the skin over the dorsal wrist capsule (preferred) or out of the skin over a bolster. Usually two or three sutures are placed.
Postoperatively, a short-arm splint is applied.
I have not found a significant difference between use of a short-arm splint and use of a long-arm or sugartong splint in regard to healing and outcome.
TECH FIG 2 • A. Meniscus repair needles with 2-0 PDS suture used for an out-to-in repair. B,C. Peripheral TFC tear with loss of compliance such that the probe sinks into the lax surface. Unlike a central tear, fibrous tissue and incomplete healing obscure the actual tear. D. Arthroscopic repair of a type 1B peripheral TFC complex tear. Two hollow needles are passed across the tear. A wire loop in one needle is used to pass 2-0 suture across the tear. The suture is tied over the capsule. E. The suture approximates the tear and restores tension to the TFCC.
OPEN REPAIR OF PERIPHERAL TFC TEARS WITHOUT ULNAR STYLOID FRACTURE
If there is significant DRUJ instability and avulsion of the TFC from the ulna fovea, an open repair is preferred.
Expose the fifth extensor compartment and retract the extensor digiti quinti minimi tendon.
Create an L-shaped capsulotomy of the DRUJ and identify the foveal attachment site of the TFC (TECH FIG 3A).
Reattach the TFC with a bone anchor or bone suture
(TECH FIG 3B–D).
Postoperative care mirrors that of arthroscopic TFC repair.10
TECH FIG 3 • Open repair of unstable TFCC avulsion. A. Dorsal exposure through the fifth extensor compartment. A DRUJ capsulotomy has been performed. B. Defining the foveal insertion site. C.Insertion of bone anchor at foveal attachment. D. Sutures in place.
OPEN REPAIR OF PERIPHERAL TFC TEARS WITH ULNAR STYLOID FRACTURE
Expose the ulnar styloid using an incision just volar and parallel to the ECU tendon.
Protect the dorsal ulnar sensory nerve and preserve the ECU sheath.
Base the method of fixation (longitudinal Kirschner wire, screw, bone anchor, or tension band) on fragment size and surgeon comfort.
If the ulnar styloid is comminuted and will not allow stable fixation, it can be excised and the TFCC attached to the ulna by a suture placed through drill holes in the ulna proximal to the fracture or using the suture anchor technique described earlier.
The patient is immobilized in a short-arm splint or cast for 4 weeks before starting rotational motion.
Surgery for Radial-Sided TFC Avulsion Tears
Assess the tear arthroscopically (TECH FIG 4A) and repair it in the manner detailed below if instability is present.
Place a burr through the 6R portal to roughen the radial attachment of the TFCC (TECH FIG 4B).
Drill two holes using a 0.062-inch Kirschner wire in a retrograde manner, starting at the TFC insertion site. These holes will allow placement of the repair suture.
The wires must exit the radius on its radial border, just volar to the first extensor compartment.
An incision is made over the exiting Kirschner wire to retract and protect the radial sensory nerve and the tendons of the first extensor compartment.
A cannula is placed in the 6R portal, through which a meniscal repair suture (2-0 PDS suture with a long straight needle at each end) is passed through the torn radial aspect of the TFCC in a horizontal mattress fashion, with each needle passing through the predrilled holes in the radius. (TECH FIG 4C).
The placement of the needles into the predrilled holes can be challenging since the holes are not visible by the scope in the 3-4 portal. Two 18-gauge spinal needles can be placed from the radial side of the radius through the bone until they can be seen in the joint at the attachment site for the TFCC. The needles provide a visible target for the meniscal repair suture needles.
If the meniscal repair suture with long straight needles is not available, pass 18-gauge needles through the bone tunnels, then directly through the torn radial TFC. A 2-0 PDS suture is passed from one 18-gauge needle to the other using a wire retrieval loop.
The suture is tied over the radius (TECH FIG 4D).
A short-arm splint is applied.
TECH FIG 4 • A. Traumatic radial TFC tear. Such an isolated tear can be débrided or repaired based on the degree of instability. B. Radial TFC tear repair. Burring of the attachment site along the sigmoid notch of the radius to bleeding bone is necessary to introduce additional vascularity and promote wound healing. C,D. Radial tears are repaired with suture on meniscal needles, tied over a bone bridge on the radial aspect of the distal radius.
POSTOPERATIVE CARE
After open or arthroscopic TFC repair, a short-arm splint or cast is applied for 4 to 6 weeks.
Range-of-motion exercises are then progressed, using a removable splint for protection initially.
Forceful wrist use is restricted for 3 months.
OUTCOMES
Arthroscopic limited débridement of the central portion of the tear will provide excellent relief of symptoms, with 80% to 85% of patients having a good to excellent result.15
The biomechanical effect of excision of the central portion of the TFCC has been examined.1,6 The excision of the central two thirds of the TFCC with maintenance of the dorsal and volar radioulnar ligaments as well as the ulnocarpal ligaments had no statistical significant effect on forearm axial load transmission. The removal of greater than two thirds will unload the ulnar column, shifting load to the distal radius and destabilizing the DRUJ.
Adams1 further emphasized that the peripheral 2 mm of the TFCC must be maintained during central débridement in order not to have a biomechanical effect on load transfer.
The results of arthroscopic repair of 1B TFCC lesions are equivalent to those reported for open repair. Gratifying outcomes are reached 85% to 90% of the time.5,6,22
The treatment of radial detachment of the TFCC from the sigmoid notch of the distal radius remains controversial.
Débridement of an isolated radial tear not associated with joint instability, similar to that for 1A lesions, yields excellent results.15
Clinical experience with open repair of radial TFC avulsion tears has also been good.6,21 Short21 reported 79% excellent and good results in his series, with return of grip strength to 90%, after arthroscopic repair of radial TFCC tears.
COMPLICATIONS
Failure to make a complete diagnosis (eg, associated ECU subluxation)
Failure to appreciate DRUJ instability
Loss of wrist motion
Injury to dorsal sensory nerves
Nonunion of the ulnar styloid or ulnar osteotomy
REFERENCES
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