➢ Arthritis and instability represent 2 of the most common pathological processes affecting the distal radioulnar joint (DRUJ). These conditions can present in isolation or as components of a multifactorial process.
➢ Nonoperative treatment is indicated for most acute injuries to the DRUJ. The joint should be immobilized in a position of stability to allow for ligament healing. Likewise, early arthritis responds favorably to rest, immobilization, corticosteroids, and nonsteroidal anti-inflammatory drugs (NSAIDs).
➢ When DRUJ instability is refractory to nonoperative measures, native ligament repair is the preferable method of treatment. When this method is not possible, anatomical reconstruction of the distal radioulnar ligaments should be performed.
➢ For advanced DRUJ arthritis Darrach resection should be reserved for the elderly, low-demand patient. The Sauvé-Kapandji procedure allows for arthrodesis of the DRUJ while maintaining forearm rotation and a stable base for the ulnar carpus.
➢ DRUJ hemiarthroplasty procedures have been associated with favorable preliminary results. These implants attempt to reproduce native biomechanics and may be used in lieu of or as a salvage procedure after resection arthroplasty. DRUJ arthroplasty should be used as a salvage procedure.
Pathological processes involving the distal radioulnar joint (DRUJ) pose a treatment dilemma because of the joint’s minimal osseous constraints. Numerous pathological processes affect this articulation, including arthritis and instability. These issues may develop separately but often coexist. Incomplete treatment may yield only nominal improvement.
The present article focuses on instability and degenerative conditions of the DRUJ. Injuries and pathological processes involving the triangular fibrocartilage complex will not be discussed in this review.
The sigmoid notch is a concavity on the ulnar aspect of the distal part of the radius that forms a loose osseous articulation with the distal part of the ulna1. The radius of curvature of the ulnar head averages 4 to 7 mm smaller than that of the sigmoid notch, allowing DRUJ translation and rotation and placing the burden of stability largely on soft-tissue stabilizers. The triangular fibrocartilage complex and interosseous membrane provide 70% to 80% of total DRUJ stability during forearm rotation2.
The triangular fibrocartilage complex arises from the ulnar aspect of the lunate fossa of the radius and inserts into the ulnar head at the base of the ulnar styloid3. It comprises the dorsal and volar radioulnar ligaments, articular disc, meniscus homologue, extensor carpi ulnaris subsheath, and ulnar collateral ligament. The dorsal and volar radioulnar ligaments tighten differentially during forearm rotation to stabilize the DRUJ in the sagittal plane, and the interosseous membrane functions as an important secondary stabilizer4,5.
Load-bearing through the DRUJ has been studied extensively and is closely related to ulnar variance. Historically, studies have shown that a wrist with neutral ulnar variance transmits 20% of forearm axial load through the ulna6. In a slightly different model in which compressive force was generated across the wrist through the action of the flexor tendons, the load borne by the ulna increased to 33% with a neutral ulnar variance7. This load was shown to increase with ulnar lengthening and to decrease with shortening6. A more recent study, however, indicated that native ulnar variance is less important than the position of the forearm (e.g., increased force occurs with pronation) in determining force transmission through the ulnocarpal joint8.
Atraumatic instability may be related to generalized ligamentous laxity, a connective-tissue disorder, or an inflammatory arthritic disease. Posttraumatic instability of the DRUJ is far more common and may manifest as articular incongruity, ligamentous disruption, or a combination of the two. Malunited fractures of the distal part of the radius, ulnar and/or radial shaft, and volar or dorsal lip of the sigmoid notch are common causes of articular incongruity. Injuries of the distal radioulnar ligament and triangular fibrocartilage complex are the primary forms of ligamentous disruption leading to instability. A recent biomechanical study showed increasing degrees of volar, ulnar, and distal displacement of the ulna with increasing dorsal angulation of the distal part of the radius after fracture9. Similarly, Jupiter and Ring found that wrist kinematics were adversely affected by dorsal angulation of >20° after distal radial fracture10. Kwon et al. reported that an ulnar-positive variance of ≥6 mm on radiographs made before the reduction of a distal radial fracture was an important risk factor for DRUJ instability11.
Displaced fractures through the base of the ulnar styloid are also risk factors for DRUJ instability12. However, recent clinical studies have failed to show improved clinical outcomes for patients undergoing fixation of displaced ulnar styloid fractures in the setting of concomitant distal radial fractures13,14.
Madelung deformity is a common congenital cause of DRUJ dysfunction. In this condition, pathological volar and ulnar tilting of the radius is attributed to growth arrest caused by a dyschondrosteosis involving the volar aspect of the ulnar third of the distal radial physis.
DRUJ arthritis can be classified as posttraumatic, inflammatory, congenital, or degenerative. Distal radial fractures extending into the sigmoid notch can produce joint surface asymmetry and can alter joint kinematics, which can lead to posttraumatic arthritis. A distal radial malunion may alter the relationship between the ulnar head and the sigmoid notch. Also, pediatric fractures involving the distal aspects of the radius and ulna have been associated with growth disturbances in 4% and 50% of cases, respectively, with the potential for future incongruity and degenerative changes to the DRUJ (Fig. 1)15.
Rheumatoid arthritis and other inflammatory arthropathies also can affect the DRUJ. Disease-modifying agents like etanercept and infliximab have rendered advanced changes far less prevalent. Madelung deformity is one of the more common congenital causes of DRUJ arthritis.
Physical examination of the DRUJ begins with careful inspection of the skin, evaluation of the resting posture, and comparison with the contralateral wrist. The importance of comparing both sides cannot be overstated, especially when the patient has underlying joint laxity. Asymmetry is a key finding that may represent distal radial malunion or advanced degenerative changes. Palpation with particular attention to the distal ulnar and styloid areas is important. Tay et al. described the “ulnar fovea sign,” defined as foveal tenderness when the examiner presses between the ulnar styloid and the flexor carpi ulnaris tendon16. In that study, a positive ulnar fovea sign had a sensitivity of 95.2% and a specificity of 86.5% for identifying a foveal tear of the radioulnar ligaments or a tear of the ulnotriquetral ligament.
Forearm pronation and supination should be assessed for limitation of motion, crepitus, and pain. The so-called shucking test is used to elicit DRUJ instability by grasping the distal part of the ulna and applying dorsal-volar forces in neutral, pronation, and supination. The findings are compared with those on the contralateral side to account for normal variations in joint laxity. Subluxation of the extensor carpi ulnaris tendon often can be reproduced by pronation and supination of the ulnar-deviated wrist. The press test is employed by asking the patient to push up from a chair with use of the affected wrist. A positive test, signified by focal ulnar-sided pain, is highly sensitive for a triangular fibrocartilage complex tear17,18.
Standard anteroposterior and lateral radiographs should be the first imaging studies performed when evaluating for possible pathological processes involving the DRUJ. Radiographs of the contralateral wrist can be especially helpful in controlling for variant anatomy. Ulnar variance, joint congruity and/or narrowing, and evidence of malunion should be noted.
Computed tomography (CT) and magnetic resonance imaging (MRI) studies may be valuable adjuncts for diagnosing pathological processes involving the DRUJ. Lo et al., with use of axial CT cuts through the DRUJ, developed the radioulnar ratio in an attempt to predict instability of the DRUJ19. The ratio of the distance from the ulnar head to the sigmoid notch compared with the length of the sigmoid notch can predict the likelihood of instability. A modified version of this method, involving the use of CT scans of the wrist made with the forearm in varying degrees of rotation, may be more accurate for diagnosing dynamic DRUJ subluxation20. Likewise, MRI has become an increasingly powerful tool for evaluating the soft-tissue supports of the DRUJ. In one study in which diagnostic arthroscopy was used as the gold standard, the sensitivity and specificity of 3-T MRI scans for predicting triangular fibrocartilage complex tears were 94% and 88%, respectively, compared with 85% and 75%, respectively, for 1.5-T scans21. Clinical correlation is imperative, however, as another study demonstrated 39 triangular fibrocartilage complex abnormalities and 23 full-thickness tears on the MRI scans of 103 asymptomatic volunteers22.
We rely primarily on the history, physical examination, and radiographs to identify pathological processes involving the DRUJ. We use CT and MRI studies sparingly. We use CT primarily to evaluate DRUJ congruity and MRI to assess soft-tissue components. Key points from the history include complaints of instability, difficulty lifting objects, and painful clicking.
Nonoperative treatment is indicated for most acute osseous and ligamentous injuries. Dorsal radioulnar ligament injuries are often stable when treated with splinting with the forearm in mid-supination, whereas volar radioulnar ligament injuries generally reduce with the forearm in mid-pronation. Fluoroscopy can be a useful adjunct to identify a position of stability. Early arthritis also often responds well to conservative treatment. As is the case with other degenerative joint conditions, rest, nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroid injections, physical therapy, and immobilization all can be effective.
Operative Treatment of DRUJ Instability
Correction of the distorted osseous anatomy of the DRUJ following a distal radial fracture is critical to the restoration of stability and normal biomechanics10,23. Malunion commonly occurs in tandem with soft-tissue injury. Adams and Berger, in a series of 14 patients who were managed with ligament reconstruction for the treatment of posttraumatic DRUJ instability, performed ligament reconstruction along with corrective osteotomies of the distal part of the radius in 2 patients with previous fractures24. Both patients went on to achieve stability of the DRUJ. In 1 patient who developed recurrent instability, osseous deficiency of the sigmoid notch was later identified. Kihara et al., in a biomechanical study, found that 20° of dorsal angulation of the radius markedly increased DRUJ diastasis23. Likewise, Jupiter and Ring reported that corrective osteotomy for patients with ≥20° of dorsal angulation resulted in improved outcomes10.
Sigmoid notch insufficiency is another possible cause of instability of the DRUJ. Several authors have reported that DRUJ instability resolved only after corrective osteotomy of a malunited sigmoid notch25,26. Recreating the native osseous anatomy of a joint with inherent osseous instability can restore a stable joint and likely represents the essential element of retensioning of the soft-tissue stabilizers.
Madelung deformity is a unique entity that deserves special consideration. In the young patient with mild deformity and substantial growth remaining, we recommend excision of the Vickers ligament and close observation. In cases of more advanced deformity, we prefer to perform a corrective osteotomy with or without an epiphysiodesis of the distal part of the ulna, depending on the amount of anticipated growth remaining in the distal part of the ulna.
DRUJ Ligament Reconstruction
Regardless of the chronicity of injury, we make every effort to repair the distal radioulnar ligaments. Ligamentous reconstruction should be performed only when primary repair is not possible. Importantly, it is not always clear preoperatively when native tissues will prove insufficient, although the need for reconstruction is more common in cases of chronic injuries.
Early techniques were developed as an alternative or adjunct to distal ulnar resection procedures. Multiple variations of extensor carpi ulnaris or flexor carpi ulnaris tenodesis procedures have been described in which the extensor carpi ulnaris and/or flexor carpi ulnaris tendon is split and passed through the ulnar head, often in combination with a distal ulnar resection (Fig. 2)27-29. Breen and Jupiter reported that the initial results of the combined extensor carpi ulnaris/flexor carpi ulnaris tenodesis were favorable, yielding a stable ulna and excellent range of motion29.
Anatomical reconstruction of the DRUJ ligaments has been developed more recently24. Our preferred technique for ligamentous reconstruction, described by Adams and Berger24, reconstructs both the dorsal and volar DRUJ ligaments (Fig. 3). In that series, 12 (86%) of 14 patients had improved stability and grip strength24. In a study of 25 patients who were managed with this technique, Henry found significantly (p < 0.05) improved Disabilities of the Arm, Shoulder and Hand (DASH) scores with no recurrent instability at 51 months of follow-up30.
Operative Treatment of DRUJ Arthritis
Distal Ulnar Resection
Darrach originally described the technique of distal ulnar resection in a patient with DRUJ instability31. This procedure has demonstrated predictable results when used for the treatment of DRUJ arthritis, especially in the low-demand patient. We use a modified version of this procedure. With the forearm pronated, a 30° to 40° radially inclined oblique osteotomy is made just proximal to the sigmoid notch to avoid leaving a sharp subcutaneous prominence (Fig. 2). Careful dissection allows for maintenance of the surrounding soft-tissue envelope, including the extensor carpi ulnaris subsheath, the interosseous membrane, and the triangular fibrocartilage complex.
Radioulnar impingement is an almost ubiquitous radiographic finding associated with scalloping of the ulnar border of the radius due to contact between the shortened ulna and the distal aspect of the radius32. When symptoms are present, the patient often complains of painful clicking and wrist instability associated with a weak grip. This constellation of symptoms is often referred to as radioulnar impaction. Symptomatic impingement can be minimized by limiting the osseous resection to just below the sigmoid notch and preserving the interosseous membrane to stabilize the residual ulnar stump31. We mark our point for resection just proximal to the sigmoid notch, ensuring complete resection of arthritic joint surfaces but avoiding excessive shortening. We routinely stabilize the residual ulnar stump with a distally based hemi-slip of the extensor carpi ulnaris tendon that is passed into the distal part of the stump and retrieved dorsally. The forearm is rotated into full pronation prior to securing the extensor carpi ulnaris tendon to itself and imbricating the remaining tissues surrounding the distal radioulnar joint.
Results following distal ulnar resection have been mixed. Grawe et al. reported an average QuickDASH score (a validated, shortened version of the DASH questionnaire) of 17 and visual analogue scale (VAS) pain score of 0.1 (of 4) in a study of 27 patients with a minimum duration of follow-up of 5 years33,34. In contrast, Bieber et al., in a series of 20 patients (mean age, 38 years) with pain and disability after distal ulnar resection, reported an average of 2.2 additional operations, with continued ulnar stump instability, weakness, and pain35. Ishikawa et al., in a long-term study of patients with rheumatoid arthritis of the wrist, reported that the Darrach procedure with extensor synovectomy resulted in a reduction in pain and an improvement in forearm rotation while accelerating ulnocarpal shift36.
Partial Distal Ulnar Resection
Partial ulnar resection techniques have been developed partly in response to the complications associated with complete distal ulnar resection. These procedures involve resection of the articular portion of the distal aspect of the ulna with retention of as much of the triangular fibrocartilage complex as possible37. Extensor retinacular flaps are raised, and the articular surface and bone are resected. The forearm is moved through a full arc of rotation to ensure that there is no radioulnar impingement38. The hemiresection-interposition technique involves placing a tendon into the resected space to maintain radioulnar separation37,38. Another variation, the matched hemiresection technique, involves concave resection of the distal aspect of the ulna in a fashion that precludes radial impingement through forearm rotation39. Favorable outcomes following hemiresection techniques have been reported for patients with traumatic injuries as well as for those with rheumatoid arthritis39,40.
The Sauvé-Kapandji procedure involves the creation of an arthrodesis of the articular surface of an arthritic DRUJ and maintains forearm rotation by creating a pseudarthrosis of the ulna proximal to the fusion site. The retained distal part of the ulna provides a stable base for the ulnar-sided carpus. Approximately 10 to 14 mm of bone, just proximal to the ulnar head, is resected. The articular surfaces of the ulnar head and sigmoid notch are prepared for arthrodesis, and the ulnar head is then reduced into the sigmoid notch and is secured with compression41. The pronator quadratus muscle belly or its fascia is advanced into the ulnar resection gap in order to prevent osseous healing across the defect and instability of the ulnar stump. Adaptations of the original description of the procedure have improved its execution over time. Two cannulated screws are now routinely placed across the articular surface to prevent rotation of the distal ulnar fragment. The original Sauvé-Kapandji procedure was performed with a single, non-cannulated screw42. Also, the original resection gap of 3 cm has decreased to a little less than half of that size as a gap of approximately 1.5 cm seems to be sufficiently wide to prevent reossification while decreasing stump instability.
Although not as prevalent in the literature as resection and hemiresection procedures, the Sauvé-Kapandji procedure has drawn favorable comparisons with those procedures in terms of reported outcomes. Zimmermann et al., in a study of 105 patients who were managed with the Sauvé-Kapandji procedure, reported that ulnar wrist pain was reduced in 102 patients (97%), that forearm rotation and grip strength were improved, and that the mean DASH score was 28 points at an average of 8 years postoperatively43. Minami et al., in a study of 61 patients who were managed with the Darrach, hemiresection-interposition, or Sauvé-Kapandji techniques, reported improved postoperative flexion, extension, grip strength, and return to previous employment in the Sauvé-Kapandji and hemiresection-interposition groups as compared with the Darrach group, whereas pain scores and pronation-supination were comparable across all 3 groups44. The Darrach group also had a higher rate of complications. Conversely, Nikkhah et al., in a systematic review comparing the Darrach and Sauvé-Kapandji procedures, concluded that the procedural complexity of the Sauvé-Kapandji procedure was not warranted by the existing evidence45.
Multiple implant arthroplasty procedures have been developed, including partial and total ulnar head replacement and total DRUJ replacement. Partial ulnar head replacement involves replacement of only the damaged, articular portion of the ulna while sparing the ulnar-sided triangular fibrocartilage complex attachments and ligaments46. This procedure is recommended as a secondary procedure for patients who have had a failure of the hemiresection-interposition procedure; however, it is contraindicated for patients with a previous distal ulnar resection or DRUJ instability due to triangular fibrocartilage complex insufficiency. One series of 3 patients showed promising results, with an average pronation of 75°, an average supination of 80°, and a 100% rate of return to work46.
Total ulnar head replacement has been described as a solution for the altered biomechanics and instability that often occur following resection procedures. In this procedure, the distal part of the ulna is resected and replaced with a stemmed prosthesis (Fig. 4)47. Sabo et al., in a study of 79 total ulnar head implants in 74 patients, reported that the implant survival rate was 90% at both 5 and 15 years48. After a mean duration of follow-up of 7 years, the patients had a functional range of pronation-supination, an average grip strength 67% of that on the contralateral side, and overall good self-reported satisfaction. Functional outcomes measures, however, demonstrated considerable residual disability, most notably in patients with posttraumatic diagnoses. Axelsson et al., in a series of 21 patients with an average duration of follow-up of 7.5 years, reported significant improvement in supination, an average DASH score of 27, symmetrical grip strength, and no evidence of radiographic loosening49.
Total DRUJ arthroplasty represents the most constrained prosthetic option and is an alternative for patients lacking native soft-tissue stabilizers. Multiple variations of the total DRUJ arthroplasty exist, but they all involve replacement of the native ulnar head and sigmoid notch with prosthetic components (Fig. 5). Initial intermediate-term results have been positive, with Axelsson and Sollerman reporting improved DASH scores and no implant loosening or major complications at an average of 3.7 years postoperatively50.
In cases of DRUJ instability in which the native soft tissues cannot be repaired primarily, we believe that anatomical reconstruction offers the potential advantage of recreating native joint kinematics. Level-IV studies have demonstrated favorable intermediate-term results in association with the use of this method. We are not aware of any higher-level studies proving superiority of this technique over tenodesis procedures; therefore, this recommendation is categorized as Grade C (Table I). Likewise, in cases of altered DRUJ osseous architecture due to malunion of the distal aspect of the radius, we recommend corrective osteotomy to restore joint stability. This recommendation is also classified as Grade C. The Darrach resection procedure has long been a mainstay in the treatment of DRUJ arthritis. Although it is accompanied by a higher rate of complications in younger patients, it continues to provide good outcomes in the elderly population. When an excisional arthroplasty is considered, we prefer the Sauvé-Kapandji procedure to maintain a load-bearing column through the ulna. Both the Sauvé-Kapandji procedure and hemiresection procedures have been shown to provide acceptable outcomes in younger patients, and both carry a Grade-C recommendation. Although we have had some favorable results with total ulnar head replacement, the unconstrained nature of these implants is worrisome, and we therefore prefer total DRUJ arthroplasty for salvage situations.
Investigation performed at the Curtis National Hand Center, MedStar Union Memorial Hospital, Baltimore, Maryland
Disclosure: There was no external source of funding for this study. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article.
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