The Distal Radioulnar Joint: Acute Injuries and Chronic Injuries





CRITICAL POINTS





  • The complex ligamentous support of the distal ulna in the shallow sigmoid notch of the radius provides a delicate balance of stability while allowing great mobility. Change in the bony alignment of either the distal radius, from a malaligned fracture, or distal ulna will limit forearm rotation and result in ulnar-side wrist pain. Injury to the ligamentous support of the distal ulna will result in excessive motion between the distal ulna and radius or between the ulnar carpus and the distal ulna. This motion will initially produce symptoms of a painful click. Chronic instability will progress to significant degenerative arthritis.



  • Successful treatment of problems involving the distal radioulnar joint (DRUJ) requires an understanding of the complex bony and ligamentous anatomy. Acute injuries are treated by correcting the bony malalignment and repair of the soft-tissue defect. Chronic injuries are treated either by stabilization or ablation of the DRUJ.



  • Negative magnetic resonance arthrography in patients with clinical suspicion of a triangular fibrocartilage complex (TFCC) tear should be interpreted with caution and the patients treated as if they have a tear.



  • The ulnar head moves within the sigmoid notch in a dorsal direction with pronation and volar with supination. The dorsal and volar radioulnar ligamentous portions of the TFCC become tight with forearm rotation serving as major stabilizers of the DRUJ controlling this translation during rotation.



Ulnar-sided wrist pain is a common symptom of patients presenting for evaluation and treatment. A significant number of these patients have pain due to pathology involving the DRUJ and its ligamentous attachments. Limitations in forearm rotation caused by DRUJ pathology limits common activities such as keyboard use, receiving change, and eating soup without spilling. This chapter reviews the bony and ligamentous anatomy of the DRUJ, diagnosis by history, physical examination, and imaging studies. Common acute and chronic injuries and their treatment are discussed.




Anatomy and Kinesiology


Bony Morphology


The DRUJ articulation consists of the sigmoid notch of the radius and the ulnar head. The sigmoid notch is a shallow semicylindrical concave notch in the ulnar aspect of the distal radius with variable depth and an average inclination of 7.7 degrees. The ulnar head is the asymmetrical semicylindrical distal end of the ulna on which the radius rotates. The articulation of the sigmoid notch with the ulnar head is not congruous because the radius of the arc of the sigmoid notch is greater than the convex arc of the ulnar head. , This incongruency produces a sliding and rolling component to the motion of the radius as it moves around the distal ulna during forearm rotation.


The radiocarpal unit rotates around a longitudinal forearm axis, defined by a straight line passing through the central radial head at the elbow and the fovea of the distal ulna. The motion is not purely axial, but involves dorsal-volar translation and proximal-distal migration. The larger radius of curvature of the sigmoid notch relative to the ulnar head allows the distal ulnar translation. The radiocarpal unit translates dorsally with supination and volarly with pronation. Proximal-distal migration occurs with rotation. The radius migrates proximally with pronation and distally with supination. From full supination to full pronation, the ulna is effectively lengthened by as much as 2 mm in relation to the radius. ,


Soft-Tissue Stabilizing Structures


The TFCC is a complex anatomic structure located at the ulnar side of the wrist. It has the important biomechanical function of providing stability to both the ulnar carpus and the DRUJ. The TFCC is a cartilaginous and ligamentous structure interposed between the ulnar carpus and the distal ulna ( Fig. 71-1 ). It arises from the distal aspect of the sigmoid notch of the radius and inserts into the base of the ulnar styloid. The TFCC attaches to the ulnar carpus via the ulnocarpal ligament complex (ulnolunate, ulnotriquetral, and ulnar collateral ligaments). The radioulnar ligaments stabilize the DRUJ, limiting rotational as well as axial migration. The dorsal and volar radioulnar ligaments (see Fig. 71-1 ) 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 radioulnar ligaments have a thick lamellar collagen structure capable of bearing tensile loads. ,




Figure 71-1


Dorsally disarticulated wrist demonstrating the triangular fibrocartilage complex (TFC) and its volar ulnocarpal ligaments: ulnolunate ligament (ull); ulnotriquetral ligament (utl); and the dorsal radioulnar ligament ( four dots ). L, Lunate; S, Scaphoid; T, triquetrum.

(From Palmer AK. Triangular fibrocartilage complex lesions: a classification. J Hand Surg . 1989;14A:585, with permission.)


The radioulnar ligaments are separated into two portions: a deep portion known as the ligamentum subcruetum , which joins and inserts into the fovea, and a superficial portion, which joins and inserts into the base of the ulnar styloid.


The volar ligament’s deep portion tightens in pronation; the superficial portion tightens in supination. The dorsal ligament’s deep portion tightens in supination and the superficial portion tightens in pronation. A commonly accepted theory of DRUJ instability states that injury of the volar margin of the TFCC allows palmar dislocation of the radius during pronation, presenting as dorsal subluxation of the distal ulna. Injury of the dorsal components of the TFCC allows dorsal dislocation of the radius in supination, presenting as palmar subluxation of the distal ulna.


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. This central portion is avascular.


The vascularity of the TFCC has been carefully studied. 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 ( Fig. 71-2 ). These vessels supply the TFCC in a radial fashion. Histologic sections demonstrate that these vessels penetrate only the peripheral 10% to 40% of the TFCC. The central section and radial attachment are avascular ( Fig. 71-3 ). This vascular anatomy supports the concept that peripheral injuries possess the ability to heal if injured and treated appropriately.




Figure 71-2


Arterial anatomy of the triangular fibrocartilage complex. br., branch; br. ant. int., branch of the anterior interosseous artery.



Figure 71-3


Axial view of the triangular fibrocartilage complex demonstrating the vascular supply to the periphery and avascular radial attachment. Arrows indicate the location of the tear in the triagular fibrocartilage complex.

(From Bednar MS, Arnoczky SP, Weiland AJ. The microvasculature of the triangular fibrocartilage complex: its clinical significance. J Hand Surg . 1991;16A:1103, with permission.)


Secondary Stabilizers


The pronator quadratus, interosseous membrane, extensor carpi ulnaris (ECU) tendon and its sheath, and flexor carpi ulnaris (FCU) tendon sheath contribute to stability but cannot prevent dislocation if the primary stability is lost.




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 ulnar carpus.


The amount of the load transferred to the distal ulna varies with ulnar variance. A greater amount is transferred in positive ulnar variance rather than negative. This results in a corresponding decreased thickness of the central portion of the TFCC in wrists with positive ulnar variance. In addition, there is a variable load placed on the TFCC with forearm rotation. Supination causes a negative ulnar variance due to the distal migration of the radius. This is reversed with pronation as the radius migrates proximally resulting in positive ulnar variance. The ulnar head also translates within the sigmoid notch in a dorsal direction with pronation and a volar direction with supination. The dorsal and volar radioulnar ligamentous portions of the TFCC become tight with forearm rotation serving as major stabilizers of the DRUJ controlling this translation during rotation.




Diagnosis


History


In most cases, a history of trauma can be elicited. The patients present with a history of a fall onto the pronated, extended wrist or a traction injury to the ulnar aspect of the wrist. , Clinical symptoms consist of ulnar-sided wrist pain, decreased strength, and a painful click at the limits of rotation.


Pain primarily with forearm rotation suggests DRUJ arthritis or instability. Pain with ulnar deviation suggests TFCC pathology or ulnar impaction. Snapping or popping symptoms occur due to subluxing or dislocating tendons, carpal instabilities, or TFCC tears. ,


Physical Examination


Physical examination immediately after an acute injury reveals swelling over the ulnar aspect of the wrist with inflammation of the tendon of the extensor carpi ulnaris (ECU). Point tenderness is present over the TFCC and distal ulna. Ulnar deviation and axial loading of the wrist (TFCC compression test) ( Fig. 71-4 ) will illicit a painful response. A click is frequently present with forearm rotation.




Figure 71-4


Triangular fibrocartilage complex compression test. Ulnar deviation and axial load applied to wrist produces pain.


The DRUJ must be assessed for instability. Instability is best assessed with the forearm in neutral rotation. The examiner stabilizes the distal radius with one hand and applies a force to the distal ulna moving it dorsally and volarly looking for increased motion or subluxation of the distal ulna relative to the radius compared with the opposite uninjured wrist. Significant instability would present as laxity of the distal ulna with a positive “piano key” sign, and dorsal prominence of the distal ulna. This would represent a significant tear or detachment of the radioulnar ligamentous portion of the TFCC.


TFCC injuries do not occur in isolation but are a component of a spectrum of injury to the ulnar side of the wrist. The examiner must therefore evaluate all the commonly injured structures on the ulnar side of the wrist. The lunatotriquetral (LT) joint must be assessed for instability caused by an LT ligament tear. This would cause tenderness over the LT interval with a positive Shuck test result. The dorsal radioulnar ligament complex should be examined to determine whether traumatic DRUJ instability is present.


The differential diagnosis for ulnar-sided wrist pain consistent with a TFCC tear would include ECU subluxation, LT ligament injury, triquetral avulsion fracture, pisotriquetral arthritis, ulnar artery thrombosis, neuritis of the dorsoulnar sensory nerve, and ulnar neuropathy at Guyon’s canal. It is a common finding that one or more of these diagnoses are present in addition to the TFCC injury.


Arthrosis or synovitis of the DRUJ is easily detected by compressing the DRUJ with a hand around the distal forearm while squeezing and rotating the forearm. Care must be taken to not compress other possible sources of pain in this maneuver and to avoid axial loading or radiocarpal torsion in the rotation to focus the examination on the DRUJ. A positive examination result will reproduce the patient’s pain and often produce crepitus when significant degeneration of the DRUJ is present. ,


Testing for ulnocarpal abutment syndrome is performed by placing the wrist in pronation and asking the patient to grip and passively ulnar deviate the hand. Limitation in ulnar deviation and reproduction of pain should be noted. , See Chapter 7 for a detailed discussion of the clinical examination of the wrist.


Imaging


Plain Radiographs


The diagnostic workup should include plain radiographs to include neutral rotation posteroanterior and lateral views. This will allow assessment for fracture, ligament instability resulting in carpal malalignment, as well as determination of ulnar variance. The determination of ulnar variance is important in that it will influence treatment options. The DRUJ must also be examined radiographically to determine whether subluxation, arthritis, or ulnar styloid abnormalities such as an acute and chronic nonunited fracture fragment are present.


CT


CT is most valuable for evaluating the distal radioulnar articulation ( Fig. 71-5 ). Degenerative changes can be clearly seen, and palmar or dorsal instability is quantified by performing axial images in full supination, pronation, and midrotation. The most useful cuts for determining instability are just proximal and distal to Lister’s tubercle. Usually, both wrists are scanned together for comparison. CT may also be used to better define the pattern of complex intra-articular fractures for preoperative planning. ,




Figure 71-5


Distal radioulnar joint. CT scan demonstrating traumatic arthritis involving the sigmoid notch of the radius.


MRI


MRI is useful in the diagnosis of TFCC tears, especially the class 1A and D lesions. , T2-weighted images in the coronal plane are of the greatest diagnostic value. The TFCC has a homogeneous low signal intensity. The synovial fluid of the joint appears as a bright image on T2 and will outline tears in the TFCC. The addition of a gadolinium arthrogram enhances the visualization of TFCC tears.


The series in the literature reviewing the sensitivity and specificity of the MRI in diagnosing injuries of the TFCC show significant variation in the reported results. Golimbu and colleagues reported a 95% accuracy of MRI in the detection of TFCC tears. They studied 20 patients with MRI; 14 had positive findings on MRI studies for TFCC pathology. These patients had surgical examination of the wrist, confirming the TFCC pathology in 13 of the patients with positive findings on MRI. None of the patients with negative findings on MRI had TFCC pathology found at the time of surgery. Schweitzer and colleagues reported 72% sensitivity, 95% specificity, and 89% accuracy in 15 patients. Zlatkin and colleagues reported 89% sensitivity, 92% specificity, and 90% accuracy in 23 patients. Potter and colleagues reported 100% sensitivity, 90% specificity, and 97% accuracy in 59 patients studied with a high-resolution magnet but only performed arthroscopy on patients with positive findings on MRI and therefore could not determine how many patients with a clinical diagnosis of a TFCC injury but negative findings on MRI had TFCC pathology.


Bednar and colleagues reported a series of 75 wrists in 70 patients with a diagnosis of TFCC injury based on clinical criteria. All patients had their MRI read by an experienced bone radiologist and then underwent wrist arthroscopy. The arthroscopic findings were correlated with the MRI and clinical examination. Of the 75 wrists with a clinical diagnosis of TFCC pathology, 71 (95%) were confirmed to have a TFCC tear by arthroscopy: 34 (48%) had a central tear, 33 (46%) had a peripheral tear, and 4 (6%) had both central and peripheral tears. Comparing the arthroscopic findings with the MRI findings produced 31 (44%) with positive findings on arthroscopy and positive findings on MRI, 40 (56%) with positive findings on arthroscopy but negative findings on MRI, and one of the four wrists with negative findings on arthroscopy had positive MRI findings. Correlating TFCC tear type with MRI showed 34 central tears with 19 (56%) MRI positive findings, 33 peripheral tears with 11 (33%) MRI positive findings, and 4 central and peripheral tears with 1 (25%) MRI positive findings. This study produced an MRI sensitivity of 44% (sensitivity is the probability of a positive finding on MRI when a TFCC lesion is present). The clinical examination sensitivity was 95%. If the patients are evaluated using the criteria used by Potter and colleagues, the study by Bednar and colleagues had 32 wrists with positive findings on MRI, of which 31 had positive findings on arthroscopy. The sensitivity for this subgroup of MRI positive patients was 97%. The MRI specificity in the study by Bednar and colleagues was 75% (specificity is the probability of a negative MRI when a TFCC lesion is absent). The MRI correlated with arthroscopic findings in 45% of the wrists studied.


Joshy and colleagues reported a series of 24 patients with a clinical suspicion of TFCC tear studied by direct magnetic resonance arthrography and then wrist arthroscopy. They found the magnetic resonance arthrography to have 74% sensitivity, 80% specificity, and 79% accuracy for detecting a full-thickness TFCC tear. They advise that negative results of magnetic resonance arthrography in patients with clinical suspicion of TFCC tear should be interpreted with caution.




Problem-Specific Management


Acute Injuries


Bony Injuries


Fractures of the Ulnar Styloid


An ulnar styloid fracture is an avulsion fracture of the major stabilizing ligaments of the distal ulna. They occur in more than 50% of distal radius fractures and are usually treated with benign neglect because routine operative repair historically has not been found necessary to obtain good results. Approximately 25% of these ulnar styloid fractures go on to nonunion. , A tear producing instability of the DRUJ should be suspected if there is radial displacement of the styloid of greater than 2 mm , and if the fracture is through the base of the styloid ( Fig. 71-6 ). The styloid should be stabilized with closed reduction and K-wire fixation or open reduction and tension band or screw fixation ( Fig. 71-7 ). If the ulnar styloid fracture is comminuted, it can be excised and the TFCC sutured to the distal ulna with appropriate tension.




Figure 71-6


Distal radial fracture with displaced ulnar styloid fracture.



Figure 71-7


Ulnar styloid fracture treated by open reduction and internal fixation.


Distal ulnar shaft fractures that are angulated disrupt the congruency of the DRUJ. DRUJ incongruency and restricted motion usually become symptomatic with 20 degrees or more of dorsal angulation. , If adequate reduction and stability cannot be obtained closed, open reduction and internal fixation with a plate and screw construct are recommended.


Intra-articular fractures of the distal ulna are rare, but as in other articular fractures, anatomic reduction should be sought. These should be treated with small K-wire fixation or small compression screws.


Acute Fractures of the Distal Radius


Distal radius fractures affect the function of the DRUJ by any combination of shortening, angulation, or articular involvement. Kihara and colleagues noted dramatic changes in DRUJ congruency with angles of dorsal inclination greater than 20 degrees, corresponding to 10 degrees of dorsal tilt of the distal radial articular surface on an x-ray. Adams noted radial shortening produced the most distortion of the TFCC.


Incongruency of the sigmoid notch articular surface will lead to painful degeneration, with radiocarpal arthrosis resulting in pain with wrist flexion and extension. Earlier studies indicated that as much as 2 mm of stepoff in the distal radial articular surface could be accepted with good outcomes. A more recent study showed that radiographic arthrosis develops in all patients with residual incongruity or stepoff, although not all are symptomatic. A CT scan should be considered to assess the congruency of the sigmoid notch and reduction of the DRUJ. Open reduction of the distal radial fracture is recommended if adequate reduction cannot be obtained and maintained by closed treatment.


Several authors examined the incidence of intracarpal soft-tissue injuries associated with distal radial fractures. Geissler and colleagues studied 60 patients and found a TFCC injury in 26 (43%). In the series of Lindau and colleagues , of 51 patients, 43 (84%) had a TFCC injury, 24 had a peripheral tear, 10 had a central perforation, and 9 had combined central and peripheral tears. In the series of Richards and colleagues of 118 patients, there was a TFCC injury in 35% of the intra-articular fractures and 53% of the extra-articular fractures.


Galeazzi’s fracture of the radius occurs at the junction of the middle and distal thirds with an associated DRUJ dislocation. Treatment is anatomic reduction of the radius with stable fixation and reduction of the DRUJ. If the reduction is stable after radial fixation, cast immobilization in supination will suffice. If there is instability but reduction is easily obtained, the author recommends arthroscopic TFCC repair pinning the reduced DRUJ in neutral rotation for 6 weeks. If there is marked instability or inability to obtain reduction, the DRUJ should be opened dorsally, reduced, and the TFCC and capsule repaired followed by pinning. ,


Radial head fractures can be associated with dislocation of the DRUJ—the Essex–Lopresti injury. This pattern indicates disruption of the interosseous membrane as well. The radial head should be reconstructed to maintain longitudinal stability of the radius. If it is not reconstructable, a metallic radial head implant should be used for the same purpose, preventing proximal migration of the radius and relative ulnar prominence at the wrist. , After repairing or replacing the radial head, the wrist should be evaluated by arthroscopy. If a TFCC tear is found, it should be repaired by arthroscopic or open methods and the DRUJ reduced and pinned for 6 weeks.


Soft-Tissue Injuries About the Distal Ulna


TFCC Tears


The classification system described by Palmer is the most useful for describing TFCC injuries, both 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.


A class 1A lesion ( Fig. 71-8A ) is 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.




Figure 71-8


A, Palmer classification of acute, traumatic triangular fibrocartilage complex (TFCC) injuries. Class 1A lesion involves a tear in the central horizontal portion of the TFCC. B, Class 1B lesion is a tear of the TFCC from the distal ulna with or without an ulnar styloid fracture. C, Class 1C lesion is a tear of the TFCC distal attachment to the lunate and triquetrum through the ulnolunate and ulnotriquetral ligaments. D, Class 1D lesion is a detachment of the TFCC from its insertion on the radius at the distal sigmoid notch.


A class 1B lesion ( Fig. 71-8B ) is an avulsion of the peripheral aspect of the TFCC from its insertion onto the distal ulna. This can either occur 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 ( Fig. 71-8C ) is an avulsion of the TFCC attachment to the ulnar carpus by disruption of the ulnocarpal ligaments. This type of lesion will result in ulnar carpal instability with volar translocation of the carpus.


A class 1D lesion ( Fig. 71-8D ) is an avulsion of the TFCC from its radial attachment. Involvement of the dorsal and/or volar radioulnar ligaments will result in instability of the DRUJ.


Treatment of acute, traumatic TFCC injuries is initially conservative, with immobilization of the wrist and DRUJ. The patient must be examined carefully to look for instability of the distal radioulnar or radioulnar joint. Routine radiographs should be obtained to detect a fracture or subluxation of the distal ulna. If the radiograph findings 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 would be expected to heal if the torn edges are held in close contact because of 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. Mikic examined the TFCC in 180 cadavers ranging in age from infant to 97 years old. He found no TFCC perforations in those wrists of individuals younger than 30 years of age. A linear progression of perforations with age was present over time such that all cadavers of those older than age 50 were found to have a TFCC perforation. This supports the concept that a defect in the central portion of the TFCC can occur without symptoms. It is those 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 that will clinically fail conservative treatment and require further treatment.


Those patients who present acutely with instability by clinical and/or radiographic criteria should be treated by arthroscopic evaluation with TFCC and ligament repair.


Those patients who remain symptomatic after adequate immobilization should be subjected to further workup to include magnetic resonance arthrography and treated arthroscopically.


The specific treatment for each class 1 lesion is determined by the type of tear found arthroscopically.


Class 1A lesions are isolated stable central tears of the TFCC. In patients with neutral or negative ulnar variance in whom conservative treatment has failed, arthroscopic limited debridement of the central portion of the tear will give excellent relief of symptoms. , The biomechanical effect of excision of the central portion of the TFCC has been examined. 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 statistically significant effect on forearm axial load transmission. The removal of more than two thirds will unload the ulnar column, shifting load to the distal radius and destabilizing the DRUJ. Adams further emphasized that the peripheral 2 mm of the TFCC must be maintained during central debridement to not have a biomechanical effect on load transfer.


Arthroscopic debridement is performed by insertion of the arthroscope through the 3,4 portal to visualize the tear and insertion of a small punch and shaver through the 6R portal to trim the tear. The dorsal ulnar portion of the TFCC cannot be trimmed from the 6R portal using a punch. It can be trimmed using a small arthroscopic knife or the edge of an 18-gauge needle, raising a flap sufficient for the punch to trim. The alternative solution is to switch the arthroscope to the 6R portal and use the punch through the 3,4 portal to accomplish the trimming of the ulnar portion of the tear.


Patients with central tears who are ulna positive or demonstrate chondromalacia may represent degenerative lesions with an overlying acute tear. These are best treated by limited debridement and ulnar recession by wafer resection or ulna-shortening osteotomy.


Class 1B lesions without an ulnar styloid fracture and a stable DRUJ can be treated by immobilization 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 are required. The ulnar styloid fracture is best approached through the sixth compartment. The distal third of the retinaculum is longitudinally divided. The ECU tendon is retracted, taking care not to disrupt the ECU subsheath. The ulnar styloid fracture will be visible once the tendon is retracted. It can be mobilized by a longitudinal incision in the periosteum. The fracture is reduced by ulnar deviation and slight supination. Fixation is performed by either a longitudinal K-wire, screw, or tension band. If the ulnar styloid is comminuted and will not hold a fixation device, it should be excised and the TFCC attached to the ulna by a suture placed through drill holes in the ulna proximal to the fracture. The suture should be placed in the periphery of the TFCC under arthroscopic guidance to confirm proper placement of the suture and restoration of proper TFCC tension. A peripheral avulsion of the TFCC should be ruled out in all patients treated for a distal radial fracture and treated in a manner similar to that for an isolated lesion.


Class 1B lesions that are present in the chronic stage at more than 3 months post-injury require arthroscopic evaluation. A peripheral tear that involves the dorsal radioulnar ligamentous portion of the TFCC can easily be repaired by arthroscopic means. The repair is performed using a two-needle technique similar to that used for repair of a knee meniscus. Initial arthroscopic evaluation may not show a discrete tear of the TFCC periphery. 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. Synovitis and a thin scar will be seen along the periphery of the TFCC at the location of the tear. A shaver will easily debride the synovium and scar to demonstrate the tear. Adhesion will be present between the undersurface of the TFCC and the distal ulna. These must be released and the TFCC mobilized sufficiently to allow advancement to reattach it and to restore proper tension. Failure to adequately debride and mobilize the chronic TFCC tear will prevent an adequate repair. After debridement, two hollow needles are passed across the tear percutaneously under arthroscopic guidance. A wire loop is passed through one needle to retrieve a 2-0 polydioxanone suture that is passed through the other needle. This allows the passage of a horizontal mattress-type suture across the tear. The authors prefer a horizontal type of suture for TFCC repair. Many other authors have reported good results using multiple simple vertical sutures placed at the periphery of the TFCC. As the suture is drawn tight, it approximates the tear and restores tension to the TFCC. The suture can be tied under the skin, over the dorsal wrist capsule, or out of the skin over a bolster. The patient is immobilized in a long arm cast for 4 to 6 weeks before restarting rotational motion and suture removal. Those patients with a nonunited ulnar styloid fragment and instability of the distal radioulnar joint due to the disruption of the TFCC require open reattachment of the styloid fragment or excision of the fragment and reattachment of the TFCC to the remaining proximal ulna.


The results of arthroscopic repair of class 1B TFCC lesions are equivalent to those reported for open repair. Hermansdorfer and Kleinman reported the results of open repair in 11 patients, with 8 of them having complete pain relief and grip strength return to 87% of normal. Cooney and colleagues reported the results of open repair in 33 patients evaluated using the Mayo Modified Wrist Score. The average score was 83, with 11 excellent results, 15 good, 6 fair, and 1 poor. Bednar reported the results of arthroscopic repair of a class 1B lesion in 40 wrists assessed using the Modified Mayo Wrist Score. The average score was 86, with 11 excellent results, 22 good, 6 fair, and 1 poor.


Trumble and colleagues reported the results of arthroscopic repair in 24 wrists (9 class 1B, 2 class 1C, and 13 class 1D lesions). The average postoperative grip strength was 85% of normal, with 89% excellent and good results, 11% fair, and 0% poor results. Corso and colleagues reported the results of a multicenter study evaluating 45 wrists from three institutions. Of 45 wrists, 27 had other associated injuries (4 distal radial fractures, 7 scapholunate ligament injuries, 9 lunatotriquetral ligament injuries, 2 ulnocarpal ligament injuries, and 2 radiocarpal ligament injuries). All TFCC injuries were repaired arthroscopically. The patients were evaluated using the Mayo Modified Wrist Score, with 29 excellent results, 12 good, 1 fair, and 3 poor.


The treatment of class 1B TFCC tears in an ulnar positive patient is determined by history and arthroscopic findings. If the patient reports an acute injury in a previously asymptomatic wrist, and arthroscopic evaluation demonstrates an acute peripheral tear with no arthroscopic findings of ulnar abutment (chronic central tear, osteochondral lesion on the ulnar aspect of the lunate), then an arthroscopic repair of the TFCC is performed. Note that the long ulna will decrease the available working space in the joint between the TFCC and the carpus, which will increase the technical difficulty of passing the repair suture. Bednar presented the results of arthroscopic repair of a class 1B lesion in an ulnar-positive wrist in 20 patients assessed by the Mayo Modified Wrist Score. The average score was 83, with 5 excellent results, 9 good, 5 fair, and 1 poor. The average grip strength was 73% of normal. If there is a history of an ulnar abutment type symptom before acute tear and arthroscopic evaluation demonstrates evidence of ulnar abutment in addition to an acute TFCC injury, then in addition to TFCC repair, ulna-shortening osteotomy is recommended. Trumble and colleagues reported the results of arthroscopic TFCC repair with ulna-shortening osteotomy in 21 patients (9 class 1B, 2 class 1C, 10 class 1D lesions) with 90% pain relief and grip strengths of 81% of normal.


Class 1C lesions involve a disruption of the ulnocarpal ligament complex. Those tears that do not heal with immobilization require operative repair to stabilize the ulnar carpus. Peripheral tears that involve the volar radioulnar ligaments or the ulnocarpal ligament complex can be repaired arthroscopically with limited open exposure to retract the ulnar nerve and artery. The success rate for open repair is 80% to 85% good and excellent results. ,


Class 1D lesions involve the radial detachment of the TFCC from the sigmoid notch of the distal radius. The treatment of these lesions remains controversial. There appears to be no vascularity to this portion of the TFCC. Theoretically, a reattached cartilage would not heal at this repair site. Clinical experience with open repair of these tears, however, has been good. This may be attributed to vascular ingrowth from the radial insertion site, which occurs with abrasion of the attachment site, stimulating the formation of new vessels. The tear needs to be assessed arthroscopically to determine its extent. If the radial tear includes disruption of one or both of the radioulnar ligaments, repair is required to prevent chronic instability of the DRUJ.


Short described an arthroscopic technique for repair of class 1D lesions. The arthroscope is placed in the 3,4 portal. A burr is placed through the 6R portal to roughen the radial attachment of the TFCC. A 0.62 mm K-wire is used to predrill two holes for the placement of the repair suture. The wires need to exit the radius on the radial side just volar to the first extensor compartment. An incision is made to retract 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 (a suture with a long straight needle at each end) is passed through the radial aspect of the TFCC in a horizontal mattress fashion with each needle passing through the predrilled holes in the radius. The suture is tied over the radius.


The placement of the needles in the predrilled holes can be challenging because the holes are not visible by the arthroscope 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 meniscal repair suture needles are not available, the 18-gauge needles can be passed directly through the radial attachment site of the TFCC. A 2-0 polydioxanone suture is then passed from one 18-gauge needle to the other using a wire retrieval loop. The needles are removed and the suture tied over the radius. Short reported 79% excellent and good results in his series, with return of grip strength to 90%.


If the radial tear does not involve the radioulnar ligaments, it is not destabilizing and debridement of the central one to two thirds of the TFCC is recommended. Osterman reported a series of 19 patients with radial TFCC tears. All tears were chronic, and no patient had instability of the DRUJ. Ten patients were treated with arthroscopic debridement and 9 with arthroscopic repair; 80% of the debridement group and 67% of the repair group were asymptomatic at follow-up. The data suggested that debridement of the radial TFCC tear was equally effective for repair in the patients with no instability.


Degenerative tears represent a spectrum of wear on the ulnocarpal articulation. Particular attention must be given to ulnar variance, which is strongly associated with the process of degeneration because it is primarily caused by overloading of the ulnar wrist. If ulnar-positive variance is present, an ulna-shortening osteotomy is indicated for any stage. An alternative is a wafer procedure removing a 2- to 4-mm slice off the ulnar head.


DRUJ Dislocations


The ulna is stationary. DRUJ dislocation occurs by displacement of the radius relative to the ulna. The ulna’s position is most evident on inspection, and dislocations are traditionally described by the position of the ulna relative to the radius. Dorsal subluxation or dislocation is more common than volar subluxation or dislocation and is produced by loading in hyperpronation and wrist extension. Clinically, the ulna is prominent dorsally, and the forearm is locked in pronation. Reduction is performed by supinating the forearm while depressing the distal ulna. If reduction occurs easily and there is good stability in supination, long-arm cast immobilization for 4 to 6 weeks in supination will usually allow adequate healing. If the DRUJ is unstable in supination, acute repair of the TFCC is performed by either an open or arthroscopic technique, and the joint should be pinned for 6 weeks. If closed reduction cannot be obtained, the joint should be opened dorsally, reduced, the TFCC repaired, and the DRUJ pinned in neutral rotation.


Volar dislocation (ulna palmar to radius) usually occurs in hypersupination and wrist extension. , The forearm is locked in supination, and reduction is performed by pronation and dorsally directed pressure on the distal ulna. If closed reduction is achieved, a long-arm cast in pronation is used for 4 to 6 weeks. Open reduction, pinning, and repair of torn structures are performed if closed reduction cannot be obtained.


Chronic Injuries


Malunions of the Distal Radius


Dorsal angulation of the distal radius of 20 degrees is disruptive of DRUJ function. Radial shortening relative to the ulna causes higher force transmission across the ulnar carpus, TFCC, and ulnar head. This leads to TFCC degeneration and ulnocarpal abutment syndrome, with eventual arthrosis of the ulnar wrist. This condition results in painful and restricted ulnar deviation of the wrist and diminished grip strength. If DRUJ arthritis is not present, the best treatment for most cases of distal radial malunion with dorsal angulation is a corrective osteotomy of the radius. , This can be performed using either a dorsal or volar approach with a trapezoidal bone graft placed to correct radial length and alignment.


A malunion that maintains normal radial inclination and radial tilt but has excessive shortening can be treated by ulna-shortening osteotomy or wafer resection of the distal ulna.


Ulnocarpal Abutment Syndrome


Ulnocarpal abutment or impaction syndrome is a painful condition caused by a relative prominence of the ulnar head relative to the articular surface of the radius (i.e., positive ulnar variance). The long ulna abuts against the central portion of the TFCC, resulting in wear and eventual erosion of the opposing ulnar side of the lunate. This causes painful synovitis of the ulnar wrist and eventually degenerative changes of ulnocarpal articulation. If the radial articular alignment is satisfactory, this can be corrected with an ulna-shortening osteotomy, which is usually stabilized with a plate. Ulna-shortening procedures decrease ulnocarpal pressure but increase pressure at the DRUJ.


If the ulna plus deformity is less than 4 mm, a wafer procedure as described by Feldon and colleagues. can be performed, resecting from 2 to 4 mm of the distal ulna either arthroscopically or open. The procedure has the advantage of being an excision, and therefore rehabilitation can progress more quickly. There is no change in the radius–ulna relationship and no increase in DRUJ pressure.


Arthritis of the DRUJ


Whether post-traumatic or inflammatory in origin, arthritis of the DRUJ can cause disabling pain and limitation of forearm rotation ( Fig. 71-9 ). When not responsive to conservative measures, a variety of surgical treatments are available.


Apr 21, 2019 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on The Distal Radioulnar Joint: Acute Injuries and Chronic Injuries
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