This chapter is dedicated to Richard A. Berger (1954–2022).
Introduction
“The ills of today do not cloud the horizon of tomorrow, but act as a spur to greater effort” (featured in William James Mayo Quotes)
This “spur” has inspired us to try to understand the distal radioulnar joint (DRUJ), referred to as the “black box of the wrist.” In this chapter, we will present what we know today, realizing that what we present was neither the “truth” 20 years ago nor may be the “truth” tomorrow.
The DRUJ connects the radius to the ulna, as well as the forearm to the carpus. This joint is at the center of function of the hand and wrist. The treatment of these disorders is common but controversial.
Anatomy and biomechanics
Rotation of the forearm in the proximal and distal radioulnar joints allows us to position the hand while maintaining grasp. These two joints together should together be looked upon as the “forearm” joint where the ulna is the stable part around which the radius rotates. The center of rotation runs through the center of the radial head proximally and through the fovea of the ulnar head distally. The seat of the ulnar head has a smaller diameter than the arc of the sigmoid notch; thus in the DRUJ rotation and translation take place, while there is a true rotation in the proximal radioulnar joint (PRUJ) ( 
A,B). In addition, there is a proximal motion of the radius in pronation. The DRUJ is stabilized by the bones, ligaments, and muscles. , The stabilizing structures include the triangular fibrocartilage complex (TFCC), the ulnocarpal ligament complex (UCLC), the extensor carpi ulnaris (ECU) tendon and sheath, the pronator quadratus (PQ) muscle, the interosseous membrane (IOM) with the interosseous ligament (IOL), the shape of the bone itself, and the capsule. ,
The TFCC is formed by the discus articularis proper, the UCLC, the soft tissue, and the ligaments running from the dorsal and palmar parts of the sigmoid notch to the ulna in two locations. The distal radioulnar ligaments (DRUL) have a superficial component running from the medial border of the radius and the palmar part of the lunate fossa to the ulnar styloid. The deep component also arising from the same areas inserts into the fovea. Studies have revealed that there might be a third, middle layer of the TFCC. The different components of the DRUL are tight in different positions of forearm rotation ( Figs. 11.1 and 11.2 ).
The conjoined part of the ligaments that attaches to the fovea is referred to as “ligamentum subcruentum.” Studies have shown that even the UCLC, the ECU tendon sheath, and the PQ muscle have fibers that intermingle with the fibers running down to the fovea. When testing the importance of the styloid insertion of the DRUL compared to the foveal insertion, static testing in different positions of forearm rotation did not show any difference, whereas in dynamic testing, the foveal insertion under loaded conditions had a greater effect on stability than the styloid insertion. Atzei and Luchetti suggested to view the TFCC as an “iceberg”: the distal component is the “emerging tip” that can be viewed from the radiocarpal joint, whereas the proximal part, the foveal attachment, is the “submerged” part. The foveal insertion is viewed as the most important ligament insertion for stability of the DRUJ.
The ECU tendon and the PQ muscle both stabilize the DRUJ. , , The IOM that runs from the ulna distally and attaches to the radius proximally transmits load from the radius distally to the ulna proximally. The IOM has a central band, often called the IOL (interosseous ligament, that has material properties and stiffness comparable to ligaments around the knee.
The distal part of the interosseous membrane (DIOM) runs from the distal ulna proximal to the ulnar head to the inferior rim of the sigmoid notch where it has a close relationship with the TFCC. The DIOM has a thicker part called the distal oblique bundle that is, however, not found in all specimens. The DIOM is a secondary stabilizer of the DRUJ and could play a major role when the DRUL or the TFCC are injured, after resection of the ulnar head or after an ulnar-shortening osteotomy. , The radial head prevents proximal migration of the radius. In a fracture dislocation such as an Essex-Lopresti fracture, however, the IOM is torn, and there is no load transfer between the two forearm bones. , ,
The radii of the seat of the ulnar head is smaller than the arc of the sigmoid notch, and translation takes place in the DRUJ during forearm rotation. The stability of the DRUJ will depend on its shape and on the shape of the sigmoid notch itself. These are revealed in CT scans. , Even the capsule, having fibers that blend “seamlessly” with the DRUL, shows properties of resisting axial or anteroposterior translation in different positions of forearm rotation.
The structures stabilizing the DRUJ are the TFCC, UCLC, ECU, PQ, IOM, the bones themselves, and the capsule. For understanding any problems in the DRUJ, all these structures should be examined. In the following, we will classify different lesions of the TFCC, present how to examine the DRUJ, and describe treatment options.
Classification of TFCC disorders
The TFCC is the most important stabilizer of the DRUJ. Palmer presented a classification of the TFCC injuries in 1989 ( Table 11.1 ).
| Traumatic Lesions: | |
|---|---|
| Class 1A: | Central rupture |
| Class 1B: | Disruption of insertion of radioulnar ligaments at ulnar fovea and/or styloid (with or without ulnar styloid fracture) |
| Class 1C: | Avulsion/tear of the ulnocarpal ligaments |
| Class 1D: | Disruption of radial origin(s) of radioulnar ligaments (with or without sigmoid notch fracture) |
| Degenerative Lesions: | |
| Class 2A: | Triangular fibrocartilage complex (TFCC) wear |
| Class 2B: | TFCC wear with lunate and/or ulnar chondromalacia |
| Class 2C: | TFCC perforation with lunate and/or ulnar chondromalacia |
| Class 2D: | Class 2C plus lunotriquetral ligament perforation |
| Class 2E: | Class 2D plus ulnocarpal arthritis |
The lesions were classified as traumatic or degenerative; the traumatic lesions were further subclassified based on the location of the injury, whereas the degenerative lesions were subclassified depending on the extent of the degenerative lesion(s). This classification is still widely used. Most of the disk has been shown to be avascular; however, in the peripheral part there is vascularity giving a potential for healing of a repair. Palmer 1B lesions are often repaired ( Fig. 11.3 ).
Several types of Palmer’s TFCC disorders have been further refined in the past 20 years by Nishikawa et al, del Piñal, and Atzei and Luchetti. , , Atzei and Luchetti divided the peripheral tears, 1B according to Palmer, into distal, proximal, and combined tears, and they suggested repair, reconstruction, or salvage procedures according to the arthroscopic findings and the extent of the injury ( Fig. 11.4 ).
Herzberg et al have presented a 3D three-part arthroscopic and functional concept of the anatomy and pathology of the TFCC. They found wrist arthroscopy to be the best option to investigate, evaluate, and treat TFCC injuries, which is minimally invasive and a relatively easy way to inspect the content of a “box” through holes rather than opening one of its faces. In this classification, both traumatic and degenerative pathologies of the TFCC have been included. The TFCC is considered as a three-part box-like structure where the first part is “The Reins, R,” including the dorsal and palmar radioulnar ligaments, the superficial and the deep components. The second part is described as the continuous peripheral ligamentous component designed to link the “R” component to the ulnar carpus. It is called “The Wall, W” component. This component surrounds the whole ulnar aspect of the ulno-carpal interval, dorsally (capsular interval between the dorsal radiotriquetral ligament, fibrous sheath floor of the ECU tendon), ulnarly (thick ulnar capsular portion including the meniscus homologue between the prestyloid recess and the “R” component), and palmarly (ulnocarpal ligaments). The third part is the fibrocartilaginous disk, the “shock absorber,” between the ulnar head and the ulnar carpus. It is called “The Disk, D” component. This new classification, a TFCC three-part concept, could facilitate the analysis and classification of combined TFCC injuries.
Recently, yet another classification, the CUP classification, has been suggested. Both these new classifications try to include more of the DRUJ and the ulnar carpus. In the last classification, the lesions are divided in three classes, CUP, based on the anatomy of the TFCC: C is central, U ulnar, and P peripheral. Each of the CUP classes are further subdivided into several types according to the severity of the lesions. Based on this, the authors have suggested treatment options.
Clinical presentations and examination
Although commonly perceived to be an instability of the wrist, DRUJ instability is, in fact, an instability of the forearm. Approximately 80% of the stability of the DRUJ can be attributed to the capsule, ligaments, surrounding muscles, and tendons that provide both static and dynamic support. , The remaining 20% is dependent on the bony shape of the DRUJ. The coronal obliquity of the DRUJ varies and has a flat surface in 55% (type I), an oblique surface in 33% (type II), and a reverse oblique surface in 12% (type III) of wrists. The transverse shape of the sigmoid notch varies from flat-faced (type A), “ski-slope” (type B), “C”-shaped (type C), and “S”-shaped (type D). The TFCC is the main soft tissue structure supporting the DRUJ with contributions from other structures. , , , ,
History
DRUJ instability can present as ulnar-sided wrist pain that is characterized by painful pronation and supination exacerbated under loading. Although mechanical snapping or clicking can occur in severe cases, this is rare. Usually, there is a history of a fall with landing on the wrist or of a high-energy twisting injury of the wrist. Hand surgeons specifically asked to examine the wrist for DRUJ instability often underappreciate or miss the diagnosis. The surgeon’s level of experience does not increase the accuracy of the diagnosis. The tests used in clinical examination for DRUJ instability can be positive for multiple conditions, and the interpretation of positive findings can be controversial.
Clinical examination
Because of the multiple conditions that are associated with and that can simulate the pain caused by DRUJ instability, examination of the DRUJ should include examination of the entire wrist including the contralateral wrist for comparison. , , , Examination of the wrist, DRUJ, and contralateral wrist can be performed in approximately 1.5 to 2 minutes ( 
). The total wrist examination including the DRUJ examination is explained step by step in 
, and the individual clinical tests for DRUJ instability are in – .
Specific tests for distal radioulnar joint instability
DRUJ ballottement test.
The DRUJ ballottement test ( 
) is one of the most used clinical tests to evaluate DRUJ instability. The test has various names, including DRUJ shift test, shuck test, and anterior posterior DRUJ displacement test. The name, the description on how to perform test, and the clinical interpretation of this test have varied over time. , , , , , Among experienced surgeons, the DRUJ ballottement test appears to be unreliable with a sensitivity of 24% and a specificity of 94%, and the presence of DRUJ instability is typically underestimated. , In our experience, this is a very useful test providing it is performed properly and considered in the context of other tests.
Technical points of this examination are:
Beginning with the symptomatic wrist, the examiner firmly grasps the distal radius, wrist, and hand ( Fig. 11.5 A and B). The distal ulna is held between the examiner’s contralateral thumb and index, middle, and ring fingers, and the distal ulna is displaced palmarly and dorsally ( Fig. 11.5 C and D).
Fig 11.5
(A and B.) The examiner firmly immobilizes the hand, wrist, and distal radius to create a single unit to test. The examiner’s grip must be very firm, otherwise normal anatomical translation of the distal radioulnar joint will occur and result in a false positive result. (C and D.) The distal ulnar is firmly held and translated dorsally and palmarly. If the test is positive, the distal ulna will displace in relation to the distal radius.
(Courtesy Jeff Ecker.)
It is essential that the distal radius, wrist, and hand are immobilized with a very firm grip so that the hand, wrist, and forearm are stabilized as a single unit. If the radius, wrist, and hand are not firmly immobilized, there will be a false-positive result caused by normal translation of the radius ( ). The test is considered positive when there is increased palmar-dorsal displacement of the distal ulna. A positive test may or may not cause pain.
The increased DRUJ laxity can be subtle, and detection relies not only on seeing the increased displacement but on feeling it. A DRUJ ballottement test should always be repeated on the contralateral wrist for comparison. If the contralateral wrist is stable, this will highlight the laxity in an unstable DRUJ.
To increase the accuracy of the test, it should be performed throughout the range of pronation and supination.
“Wind off” test (WOT).
One of the authors (JE) has developed the “wind off” test (WOT) ( 
). This is intended to be used after the DRUJ ballottement test. If both the WOT and the DRUJ ballottement test are positive, and there is no other pathology in the wrist, it is the author’s opinion that these two tests are pathognomonic for DRUJ instability.
Technical points of this examination are:
Beginning with the asymptomatic wrist, the ipsilateral elbow is rested on the ipsilateral thigh or on an examining table in neutral pronation and supination.
The examiner holds the distal forearm proximal to the wrist with the thumb on the distal ulna and index, middle, and ring fingers on the radius and supinates the forearm gently ( Fig. 11.6 A).
Fig 11.6
(A) The forearm is relaxed in neutral, pronation, or supination, and the distal radius and ulna are held between the examiner’s thumb and index, middle, and ring fingers. (B) The forearm is gently supinated. A positive test will result in pain, apprehension, and the patient moving in the direction of the provocative passive supination to avoid the pain caused by the radius subluxing dorsally on the distal ulna.
(Courtesy Jeff Ecker.)
The WOT is positive if the patient exhibits pain, apprehension, and moves in the same direction as the provocative passive supination. If done slowly, the patient will move off the chair to avoid or minimize the pain. The test has been termed “wind off” because passive supination causes the patient to “wind off” the chair to avoid the painful instability ( Fig. 11.6 B). The WOT is then repeated on the contralateral wrist for comparison.
Ulnar fovea test.
When performing the ulnar fovea test, the examiner exerts pressure on the “soft spot” immediately palmar to the ulnar styloid process and dorsal to the flexor capri ulnaris (FCU) ( 
). The test is considered positive if pressure over the “soft” spot causes pain that is similar to what the patient is experiencing. The sensitivity for detecting foveal disruptions and/or ulnotriquetral ligament injuries using this test has been reported to be 95%, and the specificity was 87% in the author’s own patients.
Technical points of this examination are:
The forearm is in neutral pronation and supination.
Pressure is exerted over the “soft” spot immediately palmar to the ulnar styloid ( Fig. 11.7 ). The pressure is maintained on the soft spot while the forearm is pronated and supinated.
Fig 11.7
Foveal sign: the thumb exerts pressure on the soft spot palmar to the base of the ulnar styloid and dorsal to the flexor carpi ulnaris tendon.
(Courtesy Jeff Ecker.)
The foveal sign is positive if there is pain under the tip of the examiner’s thumb.
DRUJ compression test.
If there is DRUJ arthritis or DRUJ instability (or both), compression of the ulnar head against the sigmoid fossa of the distal radius while passively pronating and supinating the forearm may cause pain, crepitus, or a sensation of instability with or without a clunk ( 
).
Technical points of this examination are:
Rest the elbow on the ipsilateral thigh or examining table to relax the forearm. Grasp the wrist and compress the ulnar head against the distal radius compressing the DRUJ.
Passively pronate and supinate the wrist while maintaining pressure on the DRUJ ( Fig. 11.8 A–C). The test is positive if it causes pain, crepitus, or a grinding sensation.
Fig 11.8
Distal radioulnar joint compression test. (A) The wrist is grasped to compress the radius against the ulna. (B and C) The wrist is passively pronated and supinated.
(Courtesy Jeff Ecker.)
Ulnocarpal grind/stress test.
The ulnocarpal grind test was initially developed to identify ulnocarpal impaction and subsequently evolved and designated as the ulnocarpal stress test to identify ulnar-sided wrist pathology warranting further investigation including arthroscopy ( 
). , The test is nonspecific and can be positive with an injury or pathology to the TFCC, ulnocarpal impaction, lunotriquetral and ECU instability, and DRUJ and wrist arthritis. The test can be compromised in the presence of de Quervain’s syndrome, distal intersection syndrome, and proximal intersection syndrome because the pain caused by these conditions limits the ability to forcefully ulnar deviate the wrist.
Technical points of this examination are:
The forearm is relaxed and in neutral pronation and supination with the elbow on the patient’s ipsilateral thigh or examining table. The wrist is passively deviated ulnarly.
Longitudinal compression is applied while pronating and supinating the wrist.
The test is performed in various positions of forearm pronation and supination to elicit pain and crepitus. The test is positive if it produces pain.
Piano key sign.
A positive piano key sign occurs in connective tissue disorders where there is a prominent ulnar head and supinated carpus ( 
). It can also occur in traumatic injuries of DRUJ instability and can be a normal variation. If there is a positive piano key test, the piano key test should be performed on the contralateral wrist for comparison.
Technical points of this examination are:
The patient rests the forearm on a table or flat surface and forcefully pushes on the palmar surface of the hand and then relaxes the pressure on the palm of the hand ( Fig. 11.9 A–B).
Fig 11.9
(A) A prominent ulnar head and supinated carpus can be seen with the hand and forearm resting on a flat surface. (B) When the patient is asked to push down on the palm, the distal radius and wrist move dorsally, creating the illusion of the distal ulna displacing palmarly.
(Courtesy Jeff Ecker.)
If there is DRUJi, the distal ulnar will appear to depress like a piano key, and when the pressure is released, the ulnar head will spring back to its original position. It is the distal radius and hand that moves in relation to the distal ulna creating the illusion of displacement of the distal ulna.
The examiner can also physically depress the ulnar head with the patient’s hand, wrist, and forearm flat on a table.
Tests for ECU instability and pathology.
The examination of the ECU is an essential part of the examination for DRUJ instability because ECU instability can present with mechanical ulnar-sided wrist pain and simulate or be associated with TFCC tears. The contralateral wrist must be examined for comparison because ECU instability is a normal anatomical variation and has been reported to occur in 42% of the individuals. It is easy to diagnose ECU instability when there is obvious asymmetry, subluxation, or dislocation of the ECU and if it is associated with pain, discomfort, snapping, or clicking ( 
). Smaller degrees of symptomatic ECU instability can be easily missed, and ECU instability can be incorrectly diagnosed when it is not present. When ECU instability is suspected, examination using high-resolution ultrasound is recommended, and in the future most wrist surgeons may likely use high-resolution ultrasound as part of their clinical examination.
Technical points of this examination are:
Begin with both forearms in neutral pronation and supination with the elbows resting on the patient’s thighs or examining table.
Observe any asymmetry or swelling over the sixth extensor compartment and the position of the ECU tendon ( Fig. 11.10 A).
Fig 11.10
(A) The extensor carpi ulnaris (ECU) tendon has subluxed palmarly. (B and C) The examiner’s thumb is placed palmar to the subluxed ECU tendon; as the forearm is pronated and the wrist extended, the ECU tendon can be felt to snap as it reduces into the floor of the sixth extensor compartment.
(Courtesy Jeff Ecker.)
Flex and ulnarly deviate the wrist while passively pronating and supinating the forearm to see if there is any obvious subluxation, dislocation, or snap of the ECU. The maneuver is performed with the thumb over the ECU and then palmar to the ECU to detect if there is pain on pressure and if the ECU is unstable ( Fig. 11.10 B–C). The patient is then asked to perform the maneuver actively and asked to attempt to reproduce the symptoms.
Because of the accuracy and convenience, one of the authors (JE) routinely uses high-resolution ultrasound to evaluate the ECU during clinical examinations.
Medical imaging
The interpretation of medical imaging is subjective. X-rays, CT, MRI, and ultrasound may be interpreted as normal and the diagnosis of DRUJ instability missed or incorrectly diagnosed. Malunion of the radius and/or ulna and deformity of the DRUJ can be detected on x-rays and CT studies, which may include transverse “slices” through the DRUJ in pronation and supination with comparison views of the contralateral wrist. MRI focuses on the soft tissues stabilizing the DRUJ but can also show bone edema (ulnar abutment). MRI diagnosis of TFCC tears have a sensitivity of 69% to 76% and a specificity of 41% to 60%. , Interpretation of MRI scans failed to diagnose a TFCC tear in 33% of cases when later identified during wrist arthroscopy. Although MRI provides useful information, arthroscopy remains the most accurate way to assess the anatomy and the severity of TFCC tears.
Arthroscopy
An arthroscopic classification of DRUJ instability defines TFCC tears as distal where there is a peripheral detachment of the TFCC or proximal if it involves the foveal ligament. Distal, proximal, and combined tears can coexist. Depending on the severity of the tears and the quality of the remaining TFCC, they can be repaired primarily or may require a tendon graft. The classification includes osteoarthritis (OA), which, if present, influences the choice of treatment. In this classification, the integrity of the foveal ligament and insertion can be evaluated using the so-called “hook test.” This is an arthroscopic test that is positive if the TFCC can be elevated toward the lunate by a probe inserted in the recessus of the TFCC ( Fig. 11.11 A–B). In the case of a positive hook test, the diagnosis is a tear of the foveal ligament or a disruption of the foveal insertion, which requires a repair of the foveal ligament.
The most accurate way to diagnose foveal tears is to see and probe the foveal ligament and insertion during arthroscopy. For many surgeons, it appears to be difficult to scope the DRUJ for this diagnosis. The foveal insertion of the TFCC has been reported to be visible during arthroscopic surgery in 57% to 64% of cases. , Nakamura et al has pioneered and established the use of arthroscopy to diagnose and surgically treat DRUJ instability. He was able to see the foveal insertion in 170/196 (87%) of cases. Inability to view the foveal insertion has been attributed to synovial tissue blurring the view. Recently, a dry arthroscopic technique has been developed where the foveal insertion and foveal ligament can be seen and felt with a probe in 168/169 cases (99%) ( 
– ). The increased diagnostic accuracy using dry arthroscopy may impact the choice of surgical repair in the future. After completing wrist arthroscopy, surgeons should know if there is a tear of the TFCC, the exact anatomical location of the tear, and whether the tear is repairable or whether repair requires augmentation with a tendon graft. Other causes of ulnar-sided wrist pain could be caused by other injuries of the wrist (not to be discussed in this chapter). Some key points in examination are summarized in Box 11.1 .
- 1.
The clinical signs and medical imaging of the wrist can be confusing, nonspecific, and open to different interpretations. Correlating medical history, a thorough wrist examination and imaging will result in the highest likelihood of developing a proper differential diagnosis.
- 2.
When arthroscopy of the DRUJ and wrist is added, it is nearly always possible to make an accurate diagnosis.
- 3.
Because a wide range of conditions is associated with and can simulate DRUJ symptoms, clinical and arthroscopic examination should include the entire wrist.
- 4.
In addition, clinical examination should include the contralateral wrist for comparison to define what is normal for the individual patient and whether there is bilateral wrist pathology.
- 5.
An isolated positive finding in the history, clinical examination, imaging studies, and arthroscopic examination does not provide us with a firm diagnosis. It should be considered in the light of all findings and correlated to the patient’s symptoms.
Treatment of DRUJ instability
Patients with ulnar-sided wrist pain will present with pain, pain with instability, or pain with arthritis. They may also have clicking of the wrist or a feeling of giving way and may not be able to turn a doorknob, lift a pan, use a tool, or perform an exercise or work activity as they used to. After an acute injury, the patient often thinks “This is just a bruise” and will observe for a time. They may seek their doctor, who often tells them, “Relax, it will be OK,” and often no further examination is performed. In case of clear signs of instability, however, further examinations will usually be ordered. The delay until they see a hand surgeon may be considerable.
DRUJ instability can be subdivided into two groups ( Box 11.2 ): those with an acute instability (usually considered being within three months from the injury) and those with a chronic instability (more than six months). When instability is the only symptom, treatment should focus on that. In the case of instability with pain, which has been present for a while, arthritis is usually present, and requires another treatment regime. In both cases, a thorough examination of the DRUJ as described in the previous section should be performed. This will usually reveal the problem and often the extent of the injury. An arthroscopic examination will confirm the diagnosis in most cases and should be considered to be the reference standard.
- 1.
An acute instability is within 3 months from injury, and a chronic instability has clinical symptoms more than 6 months after injury. The cases between 3 and 6 months are considered subacute.
- 2.
For acute cases, when instability is the only symptom without functional impairment, no treatment is needed, or splint protection is given.
- 3.
If instability presents with pain, splint or cast protection or percutaneous pining (such as K-wire transfixation) is suggested.
- 4.
Persistent pain, functional loss, and positive arthroscopic findings of ligament tear/disruption lead to the clinical decision for TFCC direct repair (peripheral/proximal tears: capsular suture and foveal reattachment) or reconstruction (peripheral tears, nonrepairable: DRUL reconstruction) with tendon grafts.
- 5.
In chronic cases with pain that has been present for a while, arthritis is usually present, and salvage procedures, such as arthroplasty or bone resections, are often needed. The choice of a procedure depends on the patient’s age and demands.
For acute instability, any fracture should be addressed, and the stability of the joint should be assessed. If instability is verified, the fracture(s) should be fixed, the soft-tissue injuries (usually the TFCC) should be evaluated and repaired, and the hand/wrist should be immobilized. For chronic instability, we must consider if any bony structures cause the instability and address them accordingly. For soft tissue injuries, we need to evaluate the substance of the TFCC and the DRUL and repair, if possible, or reconstruct the TFCC. In case of pain and arthritis, just addressing the bony or soft tissue issues will not resolve the problem; we should offer salvage procedures such as arthroplasty or bone resections. The latter we prefer to avoid. The preferred procedure will also depend on the patient’s age and demands. Patients should be counseled for these different procedures, their results, and complications. The ultimate decision for a specific procedure should be part of shared decision making between patient and surgeon.
In the following, we will present the different treatment options: which procedures, which complications the patient and surgeon may expect, and which are the commonly performed surgeries, depending on the experience level of the surgeon.
Nonoperative treatment
Only in the case of an acute injury with fracture dislocations and major instability should nonoperative management not be chosen primarily. , Without any fracture, a capsular TFCC rupture will probably heal when immobilized for six weeks in a cast. A retrospective has shown that immobilizing the forearm in an above-elbow cast with neutral forearm rotation and the wrist slightly in ulnar deviation will result in a clinically stable DRUJ. No literature is available treating verified foveal detachments with cast only. Analgesics or nonsteroidal antiinflammatory drugs (NSAIDs) are often used in wrist pathology. NSAIDs such as parecoxib and indomethacin may cause impaired tendon healing and possibly also ligament healing. In chronic instability, patients often wear a cast or a brace. Custom-made braces are superior because they allow less motion across the DRUJ.
Operative management
Acute isolated DRUJ dislocation.
Isolated dislocations of the DRUJ are rare but important to diagnose and treat timely ( Fig. 11.12 A–B). , These injuries should be treated with closed reduction, with or without Kirschner (K) wire transfixation, in combination with an above-elbow cast for six weeks. Reduction can be impossible due to soft tissue interposition, and this requires surgery. , The reduction can be performed as an arthroscopically assisted procedure or as an open procedure. We recommend starting with arthroscopy, and we believe this will give us a better overview of the injury to the joint. If we do not succeed with an arthroscopic procedure, we prefer an open dorsal approach through the sixth dorsal tendon compartment. Whatever approach is used, it is essential that the soft tissue should be repaired, and the stability should be tested after the repair.
Associated fractures.
In many cases, a wrist or forearm fracture can accompany DRUJ instability. A TFCC injury is often found in combination with a distal radius fracture, intraarticular as well as extraarticular, with the incidence as high as >80% when viewed arthroscopically. Some of these injuries will heal by themselves if the fracture is treated in a cast, whereas others (10%–37%) were found to cause instability. , We seldom see isolated ligamentous avulsions of the DRUL from the dorsal or palmar attachment to the sigmoid notch. However, we do see fracture avulsions with attached ligaments from the dorsal or palmar part of the sigmoid notch causing instability. Distal radius fractures with relatively small displacements can also result in instablity. , When treating a distal radius fracture surgically, we recommend evaluating the stability of the DRUJ after osteosynthesis. If an instability is found, we advise addressing it arthroscopically or addressing a concomitant ulnar styloid fracture causing instability. Ulnar styloid fractures involving the base and possibly the foveal attachment of the DRUJ should be fixed. , Thereafter the DRUJ should be stable.
Galeazzi and Essex-Lopresti fracture-dislocations will also result in an unstable DRUJ if left untreated. For Galeazzi fractures, there are several classification systems used depending on the distance of the radial fracture from the distal end of the radius, and the fracture-dislocations have also been described as simple or complex. The incidence of these fracture dislocations is 3% to 7% of all forearm fractures.
A Galeazzi fracture should be surgically stabilized, even if closed reduction is possible. After having performed the osteosynthesis, the stability of the DRUJ should be tested. If instability is found, arthroscopically assisted or open repair of the soft-tissue injury, including the TFCC, should be performed.
A fracture of the radial head with concomitant DRUJ injury was described many years ago. , Essex-Lopresti reported two cases in 1951. This type of fracture-dislocation risks proximal migration of the radius as a result of injury to the IOM as well as to the stabilizers of the DRUJ. , Radial head fractures should be fixed if possible, or the radial head replaced by a prothesis. Acutely, it is important to diagnose and treat any DRUJ instability. This injury is often overlooked, leading to a chronic problem of the DRUJ, which is more difficult to address than to treat it acutely.
The primary management of DRUJ instability should involve reduction of the joint and fixation of fractures. After reduction and fixation of fractures, the DRUJ should be evaluated intraoperatively for stability. The different tests to evaluate DRUJ instability have been described earlier in this chapter. If instability is found or suspected, this should be fixed by addressing the bone or the soft-tissue issues.
TFCC surgery.
The TFCC is the most important stabilizer of the DRUJ, and a TFCC injury is the most common cause of DRUJ instability. In Atzei and Luchetti’s classification, the IB tears according to Palmer are divided into distal, proximal, and combined tears ( Fig. 11.4 ). Proximal tears, a detachment of the foveal insertion, will cause major instability, whereas the distal capsular tears do not cause any major instability. The distal tears (according to Atzei) will cause pain and sometimes reveal clicking; however, there is a stable endpoint when testing for DRUJ stability. As with the Palmer IC tears, the foveal sign is positive.
The central portion of the TFCC serves primarily as a cushion for load transmission, whereas the peripheral portion with the palmar and dorsal radioulnar ligaments provides the stability. Instability of the DRUJ can be found when a fracture involves the palmar or dorsal parts of the sigmoid notch, and thus the ligamentous attachments, or involving a rupture or detachment of the ulnar ligament attachments. As described in the “Anatomy and Biomechanics” section earlier, other structures can also cause instability (ulnocarpal ligaments, ECU tendon and tendon sheath, interosseous membrane, the bone itself, and the capsule).
The patients often have an MRI performed by their family doctors. MRIs are not available everywhere, and the quality of the images and the skills of the interpreter are not always up to standard. Thus an MRI could reveal the injury in some cases, although arthroscopy should be considered to be the reference standard for diagnosing TFCC injuries. , As the foveal avulsion will give instability, it is important to differentiate these injuries from a peripheral or central tear to regain stability of the DRUJ.
Central tears debridement.
Most central tears do not create instability and are treated by simple debridement with good results. A laboratory study has shown that excising less than two-thirds of the disk and keeping the peripheral 2 mm of the disk did not result in significant kinematic or structural changes.
A degenerative, central tear is usually seen in patients with ulnar impaction. Just treating this with only a simple debridement will not benefit the patient. We need to reduce the load across the ulnar column by a wafer procedure (debridement of the central TFCC and the distal pole of the ulna) or ulnar shortening procedure. If DRUJ instability is found in a patient with ulnar impaction, an ulnar shortening could address both problems at the same time. If the foveal attachment of the DRUL is intact, which can be verified by arthroscopy with the scope through the central TFCC defect or by performing DRUJ arthroscopy (see previous section), ulnar shortening will stabilize the DRUJ, and this will also tighten the distal oblique bundle of the IOM. , We have found that a 3-mm diaphyseal shortening usually is enough to unload the ulnar column and to stabilize the DRUJ.
Peripheral/proximal tears: Capsular suture and foveal reattachment.
The TFCC tears, class I to III according to Atzei, or the IB tears according to Palmer will have some instability. These tears should, if the patients require surgery, be repaired. This could be performed as an open or an arthroscopically assisted procedure. We advocate use of arthroscopy as this gives us the best overview of the injury and the best option to accurately locate the repair/suture. When an open technique is used, we recommend a dorsal approach through the extensor digiti minimi (EDM) tendon sheath. A capsular suture or a foveal reattachment is performed with either an absorbable or a nonabsorbable suture. Some experts prefer absorbable sutures as they will disappear if a tendon is captured, and they create less synovitis and less risk of having to remove the suture if the patient complains of pain over the portal/scar where the suture is placed. Others claim that a nonabsorbable suture will never rupture when you tie the knot, it will give less synovitis (different experience), and the need for removal is seldom. For foveal reattachments, bone anchors or tunnels through the bone are used. Studies have been performed comparing the different techniques. Although bone anchors are favored by some, others have noted that the anchors may loosen and displace. Tunnels through the ulna give alternatives for fixation: interference screws, bone anchors, or a suture over a bone bridge ( Box 11.3 ).
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
