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Concept: Proximal radioulnar articulation

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INTRODUCTION: We present the case of a patient with extensor carpi ulnaris tendon subluxation who was first treated for distal radioulnar joint sprain. CASE PRESENTATION: A 25-year-old Caucasian man was seen at our policlinic one month after he had fallen on his outstretched hand. A diagnosis of extensor carpi ulnaris subluxation was made clinically but we also had the magnetic resonance imaging scan of the patient’s wrist which displayed an increased signal on T2-weighted images consistent with inflammation around the extensor carpi ulnaris tendon. The extensor carpi ulnaris tendon was found to be dislocating during supination and relocating during pronation. The sheath was reconstructed using extensor retinaculum due to attenuation of subsheath. CONCLUSION: There was no recurrent dislocation of the extensor carpi ulnaris tendon of the patient at his last follow up 12 months after the operation.

Concepts: Nuclear magnetic resonance, Magnetic resonance imaging, Wrist, Joint dislocation, Distal radioulnar articulation, Extensor carpi ulnaris muscle, Extensor carpi radialis longus muscle, Proximal radioulnar articulation

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Background Chronic, dynamic bidirectional instability in the distal radioulnar joint (DRUJ) is diagnosed clinically, based on the patient’s complaints and the finding of abnormal laxity in the vicinity of the distal ulna. In cases where malunion is ruled out or treated and there are no signs of osteoarthritis, stabilization of the DRUJ may offer relief. To this end, several different techniques have been investigated over the past 90 years. Materials and Methods In this article we outline the procedure for a new technique using a tendon graft to reinforce the distal edge of the interosseous membrane. Description of Technique A percutaneous technique is used to harvest the palmaris longus tendon and to create a tunnel, just proximal to the sigmoid notch, through the ulna and radius in an oblique direction. By overdrilling the radial cortex, the knotted tendon can be pulled through the radius and ulna and the knot blocked at the second radial cortex, creating a strong connection between the radius and ulna at the site of the distal oblique bundle (DOB). The tendon is fixed in the ulna with a small interference screw in full supination, preventing subluxation of the ulna out of the sigmoid notch during rotation. Results Fourteen patients were treated with this novel technique between 2011 and October 2013. The QuickDASH score at 25 months postoperatively (range 16-38 months) showed an improvement of 32 points. Similarly, an improvement of 33 points (67-34 months) was found on the PRWHE. Only one recurrence of chronic, dynamic bidirectional instability in the DRUJ was observed. Conclusion This simple percutaneous tenodesis technique between radius and ulna at the position of the distal edge of the interosseous membrane shows promise in terms of both restoring stability and relieving complaints related to chronic subluxation in the DRUJ.

Concepts: Ulna, Forearm, Tendon, Ulnar nerve, Reinforcement, Distal radioulnar articulation, Proximal radioulnar articulation, Supinator muscle

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Isolated radial head dislocation is a rare injury with an unclear pathomechanism, and the treatment is controversial. The purpose of the present study was to investigate the biomechanical contributions of the annular ligament, quadrate ligament, interosseous membrane, and annular ligament reconstructions to proximal radioulnar joint stability.

Concepts: Present, Distal radioulnar articulation, Proximal radioulnar articulation

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The radius bone has a slight dorsoradial bow that allows for full forearm pronosupination around the ulna. However, radial malunion can lead to reversal of the radial bow and subsequent volar instability of the distal radioulnar joint (DRUJ), predominantly in supination. This study assessed the outcomes of corrective radial osteotomy for volar DRUJ instability after radial malunion in children.

Concepts: Humerus, Ulna, Forearm, Wrist, Distal radioulnar articulation, Proximal radioulnar articulation, Supinator muscle

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Background Damage to the interosseous membrane (IOM) can alter load transmission between the radius and ulna and decrease their axial stability. Less is known about the effect of IOM sectioning on the transverse stability between the radius and ulna. Purpose The purpose of this study was to quantify the radioulnar gapping at the distal radioulnar joint (DRUJ) during forearm rotation when the IOM was experimentally sectioned while maintaining the integrity of the distal radioulnar ligaments. Methods In 12 fresh-frozen cadaver forearms tested in a combined wrist-forearm simulator, the increase in gap between the radius and ulna, at the level of the DRUJ, was determined during cyclic forearm rotation following IOM sectioning. Results IOM sectioning caused a significant increase in dorsal gapping at the DRUJ by 2.1 mm in supination and 0.6 mm in pronation. It also caused an increase in palmar gapping by 1.3 mm in supination and 0.5 mm in pronation. Conclusion This experiment has shown that the IOM has an important role in stabilizing the DRUJ, especially in supination, and that IOM sectioning caused greater loads on the palmar and dorsal radioulnar ligaments. Since DRUJ instability is primarily treated by fixing the laxity at the dorsal radioulnar ligament (DRUL) and palmar radioulnar ligament (PRUL), untreated IOM damage could permit additional injury and instability to the radioulnar ligaments or their reconstruction. Clinical Relevance Reconstruction of a torn IOM should be considered in the presence of persistent DRUJ instability following DRUJ reconstruction.

Concepts: Ulna, Forearm, Wrist, Distal radioulnar articulation, Pronation, Supination, Proximal radioulnar articulation, Dorsal radioulnar ligament

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Range of motion and stability are important outcome parameters to assess function of the distal radioulnar joint (DRUJ), in particular pronation, supination, and weight-lifting capacity. The DRUJ semiconstrained implant developed by Scheker et al is intended to reproduce all the functions of the triangular fibrocartilage complex and the DRUJ. The aim of the study was to investigate the subjective, clinical, and radiographic results in 10 patients after primary implantation of the semiconstrained DRUJ arthroplasty following DRUJ derangement and painful instability, with an average follow-up of 3 years with a special focus on the complications. Standardized preoperative and postoperative evaluation included assessment of pain by a visual analog scale, radiographic examination, range of motion measurements, lifting capacity, and grip strength. The patient-perceived function was investigated using clinical score charts. Compared with the preoperative status, range of motion showed little change, while grip strength, lifting capacity, pain score, and patient-perceived functions improved significantly. One patient developed an ulna stem loosening, while two patients had to be reoperated because of an irritation of the extensor tendons and the superficial radial nerve at the first dorsal compartment of the wrist. In this study, arthroplasty of the DRUJ using the semiconstrained DRUJ arthroplasty was found to result in satisfactory outcome. Level of evidence: Level IV.

Concepts: Evaluation, Assessment, Forearm, Radial nerve, Distal radioulnar articulation, Triangular fibrocartilage, Proximal radioulnar articulation, Superficial branch of the radial nerve

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This study describes a minimally invasive procedure for stabilization of the distal radioulnar joint, using a suture-button construct placed percutaneously in the direction of the distal oblique bundle in the distal interosseous membrane. In five cadaveric specimens, placement of the suture-button suspension system reduced dorsal displacement of the radius in an unstable distal radioulnar joint to baseline values, both in neutral position and in pronation and supination. These results indicate the possibility of minimally invasive treatment for distal radioulnar joint instability.

Concepts: Minimally invasive, Invasive, Invasiveness of surgical procedures, Distal radioulnar articulation, Proximal radioulnar articulation

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To compare the joint contact area and peak contact stress of different radial head (RH) hemiarthroplasty articular profiles for the proximal radioulnar joint (PRUJ) to the native radial head with the hypothesis that the side radius and side angle closest to the native mating ulnar articular profile would provide the best contact mechanics.

Concepts: Hertzian contact stress, Mechanical engineering, Forearm, Solid mechanics, Distal radioulnar articulation, Profiles, Proximal radioulnar articulation, Contact mechanics

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Proximal radial fractures are common elbow injuries. Because of the fracture pattern, stability criteria, or plate configuration, a plate position outside the “safe zone” (SZ) may be required in some cases when performing a radial head plate osteosynthesis. We examined the gross anatomy of the radial head and analyzed different so-called low-profile and precontoured radial head and neck plates with respect to the SZ.

Concepts: Bone, Head and neck anatomy, Head and neck, Fracture, Distal radioulnar articulation, Proximal radioulnar articulation

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Background: To date, the Aptis distal radioulnar joint (DRUJ) prosthesis by Scheker is the only total, bipolar prosthesis available. In the literature, only few data exist concerning the prosthesis and its surgical technique. Aim of the present study was the evaluation of the medium-term clinical and radiological outcome following implantation of the Aptis DRUJ prosthesis. Methods and Patients: 5 patients (4 women and 1 man) with mean age of 40.2 (30-65) years underwent secondary implantation of the Aptisprosthesis between February 2006 and May 2013. The average date of the follow-up was after 36 (24-48) months. Besides the complications, the wrist range of motion (ROM) and the strength in grip were measured. The quality of pain was determined using a visual analogue pain scale from 0-10. In follow-up X-ray controls, bone resorption and bony abnormalities were evaluated. The DASH score as well as the postoperative subjective satisfaction of the patients were recorded. Results: No patient required removal of the prosthesis. Only 1 patient underwent secondary surgery in which debridement of the screw tip over the radius was required. The postoperative range of motion in pronation and supination was measured with 78 (70-90)° and 82 (70-90)°. The average grip strength amounted to 29 (24-32) kg. This represented 85 (76-100)% of the value of the contralateral side. Postoperative pain symptoms on the visual analogue pain scale were measured with 0 points at rest and with 1.2 (0-2) points under strain. Radiological evaluation showed bone resorption at the radial peg in 2 patients, but without evidence of implant loosening. The DASH score was recorded with 37 (13-75) points. All patients were satisfied or very satisfied after the surgical treatment. Conclusion: The Aptis prosthesis is a safe and efficient treatment option for previously failed surgery of the DRUJ.

Concepts: Bone, Hospital, Surgery, Physician, Pain, Amputation, Distal radioulnar articulation, Proximal radioulnar articulation