Acute Distal Radioulnar Joint Instability: Evaluation and Treatment

Ulnar Bowing and Distal Radioulnar Joint Anatomy: A Three-Dimensional, In Situ Clinical Assessment

Purpose

Distal radioulnar joint (DRUJ) injuries can be devastating and challenging to manage. The multiplanar curvature exhibited by the ulna impacts the morphology of the DRUJ, making it difficult to assess through two-dimensional radiographs alone. We used full-length, three-dimensional (3D) computed tomography angiography scans to assess the relationship between ulnar bowing, DRUJ ulnar variance (UV), and sigmoid notch angle. The goal of this study was to establish normal anatomic ranges for these landmarks to improve treatment for forearm traumas and DRUJ pathologies.

Methods

Eighty-two intact upper extremity computed tomography angiography scans were examined and reconstructed into 3D models. We characterized ulnar bowing and DRUJ metrics using computer-aided design software. Measures of central tendency and Pearson correlation coefficients were calculated for comparative analysis.

Results

The study yielded an average ulnar length of 272.3 mm. We identified the proximal ulnar bow at 36.7% of the bone's total length, possessing a depth of 10.3 mm, a proximal angle of 6.6°, and a distal angle of 3.9°. The distal ulnar bow appeared at 75.3% of the bone's length, characterized by a depth of 4.2 mm, a proximal angle of 2°, and a distal angle of 4.3°. In the coronal plane, the proximal angle of the proximal ulnar bow correlated positively with UV (r = 0.39, P < .001), whereas the distal angle of the distal ulnar bow correlated negatively (r = -0.48, P < .001). We also found significant correlations between the depths of both proximal and distal bows with UV (r = 0.38, P < .001; r = -0.34, P < .001, respectively). Moreover, UV within the DRUJ strongly correlated with the sigmoid notch angle (r = -0.77, P = .01). In contrast, the sagittal plane metrics did not show meaningful correlations with UV.

Conclusion

Sagittal alignment and translation at the DRUJ articulation are directly related to ulna bowing at the distal ulna. A nuanced understanding of these 3D relationships can enhance preoperative planning when correcting ulnar-side pathology.

Type of study/level of evidence

Therapeutic IV.

A structured non-operative treatment program for traumatic triangular fibrocartilage complex tear: A quasi-experimental study

OBJECTIVES

Triangular fibrocartilage complex (TFCC) injury is a common cause of ulnar-sided wrist pain. However, treatment protocols vary across clinical settings and a standardized treatment protocol is needed to improve quality of care. We devised a rehabilitation regime which comprised both orthoses and exercises. We hypothesized that the program can effectively reduce pain and improve functional performance.

MATERIALS AND METHODS

Thirty-two subjects participated in the 5-phase rehabilitation program. Progress was monitored every 3 weeks. Outcome measures comprised numeric pain rating scale (NPRS), activities of daily living (ADL) pain score, wrist range of motion (ROM), ADL performance score, patient-rated wrist evaluation (PRWE), power grip and distal radioulnar joint (DRUJ) instability grade.

RESULTS

NPRS decreased from 5.3/10 to 0.5/10 while the ADL pain score improved from 10/20 to 19.1/20. ROM in flexion/extension and supination/pronation improved by 35%. Functional performance on ADL performance score and PRWE improved from 21/40 to 38/40 and 49.5/100 to 14.6/100, respectively. Power grip increased by 59.5%, and DRUJ stability improved.

DISCUSSION

The combination of orthoses and progressive strengthening and proprioception training was effective in re-establishing DRUJ stability, and improving wrist strength and functional performance.

CONCLUSIONS

This study provided insight for the development of a rehabilitation protocol for patients with TFCC injury.

Acute isolated volar distal radioulnar joint dislocation: first surgery or conservative?

Isolated distal radioulnar joint (DRUJ) dislocations are referred to as dorsal or volar of neglected isolated volar DRUJ dislocation which was detected at the second dislocations concerning the position of the ulnar head in relationship to the radius. In contrast to large joint dislocations such as a shoulder dislocation, the clinical picture may mimic a simple soft tissue injury and the dislocation may be missed. In this article, we aimed to present a case presentation to the emergency department. Our patient who had no complaint other than wrist pain was diagnosed with volar dislocation on lateral radiography and closed reduction was performed in the emergency department with sedation. There was no recurrence in the follow-up and we achieved a satisfactory result with a painless and unrestricted wrist joint at six months. DRUJ and the ligaments stabilize the joint work in anatomical coordination and play an important role in forearm rotation movement. Traumatic injuries to these structures range from isolated tears to severe fractured dislocations. Isolated DRUJ dislocations are rare. Initial treatment of this injury is closed reduction, post-reduction stability is important and fixation is required in case of instability. Although surgical treatment is performed in cases that cannot be closed reduced and in the presence of instability after reduction, it is possible to obtain successful results in acute cases with closed reduction performed with sedation in emergency departments. For this reason, a conservative approach should be tried before making a surgical decision in these injuries that require special attention in diagnosis.

Ulnar positive variance associated with TFCC foveal tear

OBJECTIVE

The ulnar positive variance (UPV) can be observed on simple radiography due to a triangular fibrocartilage complex (TFCC) foveal tear. This study investigated to identify how much radiographic UPV occurs due to a TFCC foveal tear, which may be misdiagnosed as an ulnar impaction syndrome (UIS).

MATERIALS AND METHODS

One hundred forty patients who underwent arthroscopic transosseus TFCC foveal repair from March 2013 to March 2019 in our institution were enrolled in this study. Ulnar variances were measured in preoperative, postoperative 6 weeks, 1-year follow-up wrist posteroanterior (PA) radiograph, and power grip PA radiograph of the affected wrist and were compared with those of the same patient's unaffected wrist.

RESULTS

In the neutral wrist PA radiograph, ulnar variance increased by 0.56 mm (p < 0.001) after TFCC foveal tear compared to the unaffected side. In the power grip view, ulnar variance also increased by 0.39 mm (p < 0.001) in the affected wrist. The preoperative ulnar positive variance was reduced after an arthroscopic transosseous TFCC foveal repair from 0.56 to 0 mm (p < 0.001). No significant statistical difference was observed between an Atzei class 2 and 3 TFCC tear (0.56 mm vs. 0.41 mm, p = 0.263).

CONCLUSION

This study revealed that TFCC foveal tear induces 0.56 mm of radiologic UPV, which was successfully corrected after arthroscopic transosseous TFCC foveal repair. Therefore, UPV associated with TFCC foveal tear should not be misdiagnosed as an UIS. Also, when ulnar shortening osteotomy is planned in case of UIS combined with TFCC foveal tear, the amount of UPV induced by TFCC foveal tear should be considered to prevent over-shortening.

Structurally intact and functionally incompetent foveal triangular fibrocartilage complex injuries : an under-recognized spectrum of injury

Injury to the triangular fibrocartilage complex (TFCC) may result in ulnar wrist pain with or without instability. One component of the TFCC, the radioulnar ligaments, serve as the primary soft-tissue stabilizer of the distal radioulnar joint (DRUJ). Tears or avulsions of its proximal, foveal attachment are thought to be associated with instability of the DRUJ, most noticed during loaded pronosupination. In the absence of detectable instability, injury of the foveal insertion of the radioulnar ligaments may be overlooked. While advanced imaging techniques such as MRI and radiocarpal arthroscopy are well-suited for diagnosing central and distal TFCC tears, partial and complete foveal tears without instability may be missed without a high degree of suspicion. While technically challenging, DRUJ arthroscopy provides the most accurate method of detecting foveal abnormalities. In this annotation the spectrum of foveal injuries is discussed and a modified classification scheme is proposed.Cite this article: Bone Joint J 2023;105-B(1):5-10.

Case report: Isolated acute dorsal distal radioulnar joint (DRUJ) dislocation

Introduction

Isolated acute distal radioulnar joint (DRUJ) dislocation is a rare injury that should be early recognized and treated promptly to avoid the limitation and disability associated with delayed diagnosis and management.

Case presentation

We present a patient with a traumatic dorsal isolated DRUJ dislocation who was successfully treated with a closed reduction and k-wire pinning along with cast immobilization.

Discussion

Previous reports of distal radioulnar joint dislocation have described the mechanics of this injury as well as a guidance to diagnosis and treatment. Closed reduction, stabilization of wrist joint, and early mobilization of elbow joint can help in preserving the joint function and a faster recovery.

Conclusion

Closed reduction under general anesthesia, DRUJ stabilization by k-wire pinning, and above elbow casting can be successful in most cases. We recommend an early transition to below elbow cast to encourage early elbow range of motion and prevent joint stiffness.

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Isolated acute distal radioulnar joint dislocations are rare injuries.

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Early diagnosis and prompt treatment are mandatory to obtain satisfactory outcome.

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Postoperatively, early transition to below-elbow cast prevent elbow stiffness and allows a speedy recovery.