Distal Radioulnar Joint Instability

Suture-Based Distal Radioulnar Joint Stabilization: A Biomechanical Evaluation in a Cadaveric Model

Purpose  Management of acute distal radioulnar joint (DRUJ) instability is complex and controversial. Common treatment options include prolonged immobilization, stabilization with wires, and acute triangular fibrocartilage complex repair. However, none of these permits an early range of motion. The purpose of this study is to investigate the feasibility of a suture-based stabilization (SBS) technique for acute DRUJ instability to permit early active motion. Materials and Methods  A biomechanical study utilizing eight cadaveric arms was performed. All specimens were tested in the intact state prior to the creation of bidirectional DRUJ instability. For the SBS group, 2-mm suture tapes with suture button fixation were utilized to recreate the respective contributions of distal oblique bundle and volar and dorsal radioulnar ligaments to DRUJ stability. All specimens were cyclically loaded with a simulated ballottement stress of 20N in forearm positions of neutral, 60 degrees of pronation and 60 degrees of supination. Range of motion and total translation were measured and then compared between the two groups. Results  The average range of motion in the intact and SBS specimens was 174 and 175 degrees, respectively. There were no significant differences in displacement between the intact and SBS group in neutral and in supination. However, the SBS group had less translation than the intact group in pronation. Conclusion  For acute DRUJ instability, the described SBS technique provides similar stability to the native intact DRUJ without compromising the range of motion in a cadaveric model. Future comparative studies are warranted prior to translation into the clinical arena. Clinical Relevance  This is a biomechanical study investigating a treatment technique for acute DRUJ instability that would allow an early range of motion.

Ligament reconstruction for distal radioulnar joint instability with the biomechanical analysis: A case report

RATIONALE

The aim of the study is to evaluate the clinical effects and feasibility on chronic distal radioulnar unstable joint (DRUJ) under wrist arthroscope triangular fibrocartilage complex (TFCC) repair and reconstruction. The biomechanical characteristics of the recovery process after treatment were analyzed using finite element modeling.

PATIENT CONCERNS

A patient with chronic DRUJ instability was treated with reconstruction of the distal radioulnar ligament using the Adams Berger method. Piano sign and forearm rotation tests were used to evaluate the function of the DRUJ. Grip power, range of motion, and visual analog scale scores were recorded at the last follow-up. Joint function was evaluated by the disability of the arm, shoulder, and hand score. A geometric model for the surgical repair of TFCC damage, meshing in finite element simulation, and stress distribution of the repaired ligament during forearm rotation were analyzed by finite element simulation.

DIAGNOSES

The diagnosis was confirmed as chronic DRUJ instability.

INTERVENTIONS AND OUTCOMES

The patient had no postoperative complications and was followed-up for 6 months. Stability was achieved in all patients. The results of the stress and forearm rotation tests are negative. At the last follow-up, the grip power, disability of the arm, shoulder, and hand score, visual analog scale score, and range of motion of the wrist were significantly improved compared with the preoperative values (P < .05).

LESSONS

TFCC repair and reconstruction under wrist arthroscopy can effectively treat chronic DRUJ and improve wrist function. Our study established a three-dimensional finite element model of the entire DRUJ, which provided a digital visual platform for simulating the biomechanical features of the TFCC, DRUJ, and other structures in different states. This study demonstrated that the rotation angle of the wrist joint should be confined within 75° for a short period after surgery to avoid tearing the tendon as a result of excessive force. It also provides an intuitive simulation tool for the design of TFCC repair and the evaluation of curative effects.

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.

Biomechanical Outcomes of Surgically Repaired TFCC Palmer Type 1B Tears: A Systematic Review of Cadaver Studies

BACKGROUND

Palmer type 1B triangular fibrocartilage complex (TFCC) tears are a common cause of distal radioulnar joint (DRUJ) instability. Unfortunately, the best surgical technique for TFCC reinsertion is still unknown, and up to a quarter of patients report instability after repair. The purpose of this systematic review of cadaver studies was to compare the biomechanical outcomes of different surgical techniques used for Palmer 1B TFCC tears.

METHODS

A systemic review of all cadaver studies published before January 2022 was performed using the PubMed and EMBASE databases. Only cadaver studies on reinsertion techniques for Palmer type 1B lesions were included. Biochemical outcome parameters evaluated were stability of the DRUJ and strength of the repair.

RESULTS

A total of 248 articles were identified. Five articles fulfilled the inclusion criteria. Four different surgical techniques were identified. In 3 studies, transosseous tunnel repair was tested and resulted in the most stable DRUJ and strongest TFCC repair compared with the suture anchor repair, the peripheral capsular repair, and the outside-in repair.

CONCLUSIONS

These results suggest that the transosseous tunnel repair might be a good technique for restoring DRUJ stability. However, more cadaver studies are needed to identify the most optimal technique.

Comparative Analysis of Treatment Outcomes: Modified Ulnar Gutter Slab vs. Sugar Tong Slab for Distal Radioulnar Joint Instability Following Triangular Fibrocartilage Complex Repair

The standard treatment for distal radioulnar joint (DRUJ) instability involves repairing the triangular fibrocartilage complex (TFCC) and immobilizing the joint with a sugar tong slab, but this can cause elbow stiffness. To address this, a modified ulnar gutter slab was designed to enhance elbow mobility during immobilization. A prospective randomized controlled trial was conducted on 23 DRUJ instability patients who underwent arthroscopic TFCC repair. Two post-operative splinting techniques were compared: the modified ulnar gutter slab and the sugar tong slab. The assessment included the Disabilities of Arm, Shoulder, and Hand (DASH) score; elbow, forearm, and wrist range of motion (ROM); post-operative DRUJ stability; and complications. DASH scores at 4 and 6 weeks were not significantly different. However, the modified ulnar gutter slab improved elbow extension range of motion at 4 weeks (extension lag: 20.0 vs. 6.5 in the sugar tong group) (p = 0.011). Post-operative DRUJ stability was comparable between the two groups. Notably, one patient in the sugar tong slab group experienced complex regional pain syndrome (CRPS). The modified ulnar gutter slab offers a post-operative alternative after TFCC repair. It effectively immobilizes forearm and wrist motion while enhancing elbow mobility, potentially reducing post-operative elbow stiffness.