Instability of the distal radioulnar joint

Predictive factors of distal radioulnar joint instability after surgical treatment of distal radius fractures

Distal radioulnar joint (DRUJ) instability is a common postoperative complication of distal radius fractures, seriously impacting patients' quality of life. This study investigated its possible influencing factors to determine prognosis and to guide treatment better. We retrospectively included a series of patients with distal radius fractures that underwent volar locking plate fixation. Basic patient information and imaging parameters were collected. The incidence of DRUJ instability during follow-up was recorded, and factors associated with DRUJ instability were determined using univariate analysis and multifactorial logistic regression analysis. A total of 159 patients were enrolled in this study. At 6 months of follow-up, 54 patients (34.0%) had DRUJ instability, and multivariate analysis showed coronal plane displacement (OR, 1.665; 95% CI, 1.091-2.541), fracture classification (OR, 0.679; 95% CI, 0.468-0.984) and DRUJ interval (OR, 1.960; 95% CI, 1.276-3.010) were associated with DRUJ instability after volar locking plate. DRUJ interval, coronal plane displacement, and fracture classification are associated with DRUJ instability during follow-up. Therefore, preoperative risk communication and intraoperative attention to recovering relevant imaging parameters are necessary for these patients.

Midterm Functional Outcome of the Linked Semiconstrained Distal Radioulnar Joint Prosthesis

Background  A painful unstable distal radioulnar joint (DRUJ) can seriously compromise hand and wrist function. The semiconstrained prosthesis was developed to restore DRUJ function. To date, most outcome reports are coauthored by the designer. Questions  Does independent reporting confirm the promising results of the semiconstrained DRUJ prosthesis? Are complication and failure rates acceptable? Patients and Methods  We evaluated patients with the semiconstrained DRUJ implant and a minimum follow-up of 2 years. We monitored patient satisfaction and function with functionality questionnaires and measured wrist range of motion, grip, and key pinch strength. Statistical analysis was done using descriptive statistics, Pearson correlation coefficients, linear and logistic regression. Results  We included 41 patients with 42 implants. Mean follow-up was 46 months (range: 24-102 months). Eighty percent of wrist had undergone previous surgery. We found a mean pronation of 83 degrees (0-90 degrees), supination of 70 degrees (0-90 degrees), flexion of 42 degrees (0-90 degrees), extension of 49 degrees (0-90 degrees), ulnar deviation of 24 degrees (0-60 degrees), and radial deviation of 14 degrees (0-40 degrees). Grip and key pinch strength were 20.1 (1-50 kg) and 6 kg (1-12 kg), respectively. Average patient-rated wrist and hand evaluation score was 42.7 (0-95), disabilities of the arm, shoulder and hand score was 38 (0-88), and visual analog scale score was 3.6 (0-8). We found a 43% complication rate (mostly minor: ulnar or radial tendinopathy, temporary hypoesthesia) with 24% reoperation and 92% prosthesis survival rate. Conclusion  The linked semiconstrained DRUJ prosthesis has its value in the surgical treatment of DRUJ failure. Currently, most implants are used in secondary surgery and multioperated wrists. More research is required to assess the value of the DRUJ prosthesis as a primary procedure. Level of evidence  This is a level IV, therapeutic study.

Wrist weight-bearing tolerance in healthy adults

STUDY DESIGN

Cross-sectional.

INTRODUCTION

No information is available in the literature regarding the amount of weight-bearing tolerance in a normal human wrist.

PURPOSE OF THE STUDY

To establish the normal limits of human wrist weight-bearing tolerance and to determine if gender, age and height are predictors of this weight-bearing tolerance.

METHODS

A sample (N = 465) of healthy adults ages 18-64 completed a questionnaire indicating their gender, age range and height. Subjects were instructed in performing a wrist weight-bearing tolerance test using a calibrated analog scale. The amount of pressure that the subject was able to apply to the scale in 3 independent trials was recorded and analyzed.

RESULTS

A strong positive correlation was found between average weight- bearing values achieved through the right and left hands for the subjects of this study, r(463)= .97, P < .001. A 2-way analysis of covariance revealed main effects for both gender (20.9, 95% CI [15.7, 26.0] pounds, P < .001) and age (F(4, 454) = 6.143, P < .001, partial η² = .051). The highest weight-bearing tolerance was observed in males and individuals 25-34 years of age. Multiple regression analysis affirmed that gender, height and age categories of 45-54 and 55 to 64 were all statistically significant predictors of wrist weight-bearing tolerance, P < .01.

DISCUSSION

These results establish normal wrist weight-bearing tolerance values and demonstrate that gender, age and height are predictors of this weight-bearing tolerance.

CONCLUSION

These results could allow identification of pathologies associated with wrist instability.

Radius distraction during volar plating of distal radius fractures may improve distal radioulnar joint stability at minimum 3-year follow-up: a retrospective case series study

Background

The surgical technique of radius distraction for stabilization of distal radioulnar joint (DRUJ) if intraoperative DRUJ instability was found after the fixation of distal radius fracture has been previously described, but this surgical technique lacks clinical and radiographic effect in minimal 3 years follow-up. We therefore evaluated the clinical outcome and radiographic results of radius distraction in minimal 3 years follow-up as long-term evaluation.

Methods

We reviewed the case series of distal radius fracture with concomitant DRUJ instability receiving radius distraction from the senior author over a 5-year period (January 1^st, 2013, to June 30^th, 2017) retrospectively. Radius distraction during volar plating was performed by moving the volar plate distally via compression screw loosening/fastening to achieve firm endpoint on the dorsopalmar stress test. The evaluations of radiographic, including bone union time and ulnar variance, and clinical outcomes, including grading of DRUJ instability, NRS of wrist pain, DASH score, MMWS score, and range of motion of operated wrist at final follow-up, were performed at clinic as minimum 3-year follow-up; a total 34 patients had been evaluated.

Results

At minimal post-operative 36 months follow-up, all cases demonstrated acceptable wrist range of motion with stable DRUJs, low NRS of wrist pain (0.6, SD 0.7), and satisfactory DASH score (mean 9.1, SD 6.2) and MMWS score (mean 87, SD 10). There were no cases suffering from nonunion of distal radius. The mean ulnar variance of injured wrist and uninjured wrist were -1.2 mm and 0.2 mm, respectively (SD 1.0 and 0.6) with significant statistical difference.

Conclusions

Radius distraction during volar fixation of distal radius fracture should be considered if DRUJ instability was found by the dorsopalmar stress test intraoperatively, and the long-term DRUJ stability could be achieved by maintenance of normal-to-negative ulnar variance, with decreased wrist pain and satisfactory function outcome.

Level of Evidence

Therapeutic Level IV

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05108-z.

Treatment Options for Distal Radioulnar Joint Arthritis: Balancing Functional Demand and Bony Resection

The distal radioulnar joint is a complex anatomic structure that allows for a combination of rotation and translation with extrinsic and intrinsic stabilizers that maintain stability through a delicate equilibrium. Traumatic, congenital, inflammatory, and degenerative processes can disturb this sensitive balance, resulting in distal radioulnar joint arthritis. We discuss the joint's anatomy and biomechanics and the clinical approach to the patient. We review the surgical treatment options, expected outcomes, and their shortcomings. Selecting the best surgical intervention often means choosing the procedure with the set of complications and limitations best suited for the specific patient.

Hemiresection Interposition Arthroplasty of the Distal Radioulnar Joint: A Long-term Outcome Study

Background: The aim of this study was to assess factors associated with long-term patient-reported functional, pain, and satisfaction scores in patients who underwent (Bowers) hemiresection interposition technique (HIT) arthroplasty of the distal radioulnar joint (DRUJ). The secondary aims were to determine the complication and reoperation rates. Methods: A retrospective study with long-term follow-up of patients undergoing HIT arthroplasty was performed. Demographic, disease, and treatment characteristics were collected for the 66 included patients. Thirty-one patients completed all surveys, which were the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), our custom-made HIT arthroplasty questionnaire, Numeric Rating Scale (NRS) for pain, and NRS for satisfaction. The mean interval between surgery and follow-up by means of questionnaires was 8.6 ± 3.4 years. Results: The mean QuickDASH score was 31.0 ± 20.2. The mean score of the HIT arthroplasty questionnaire was 2 ± 2. The median NRS for pain was 1 (interquartile range [IQR], 0-3), and the median NRS for satisfaction was 9 (IQR, 8-10). The complication rate and reoperation rate were 14% and 8%, respectively. Conclusion: Overall, patients expressed satisfaction with HIT arthroplasty, despite a mean QuickDASH score of 31.0. In our cohort, patients with inflammatory arthritis had higher satisfaction and lower pain scores. Patients who had prior trauma, prior surgery, or DRUJ subluxation are generally less satisfied. Men, older patients, and posttraumatic patients had higher long-term pain scores; however, posterior interosseous nerve neurectomy is associated with improved pain scores. Our findings support the use of HIT arthroplasty in patients with inflammatory arthritis.

Distal Radioulnar Joint Instability: Assessment of Three Intraoperative Radiographic Stress Tests

Background: The purpose of this study is to describe three radiographic stress tests that could be used to examine for distal radioulnar joint (DRUJ) instability intraoperatively, and to determine their ability to detect DRUJ instability after sequentially sectioning the DRUJ. Methods: Eleven fresh frozen cadaveric upper extremities (mean age 52.6 ± 14.9 years) were obtained. We sequentially sectioned the DRUJ. After each component of the DRUJ was sectioned, we performed three radiographic stress tests-squeeze test, ulnar pull in coronal plane, and simulated DRUJ ballotment test. Results: The squeeze test detected a significant increase in diastasis relative to the intact DRUJ after sectioning of the foveal insertion of the triangular fibrocartilage complex (TFCC; 1.0 mm) and the distal oblique bundle (DOB; 1.2 mm). The ulnar pull test in the coronal plane detected a significant increase in diastasis relative to the intact DRUJ after sectioning of the dorsal and volar radioulnar ligaments (2 mm), the foveal insertion of the TFCC (2.6 mm), and the DOB (4.4 mm). The simulated DRUJ ballotment test detected a significant increase in dorsal translation of the ulna relative to the intact DRUJ with sectioning of the foveal insertion of the TFCC (4.9 mm) and the DOB (5.6 mm). Conclusion: The squeeze test and simulated DRUJ ballotment test detect a significant increase in diastasis after the foveal attachment of the TFCC was sectioned. The ulnar pull test in the coronal plane was the most sensitive test for detecting a significant increase in diastasis relative to the intact DRUJ.

Contribution of a distal radioulnar joint stabilizer on forearm stability: A modeling study

Instability of the forearm is a complex problem that leads to pain and limited motions. Up to this time, no universal consensus has yet been reached as regards the optimal treatment for forearm instability. In some cases, conservative treatments are recommended for forearm instability injuries. However, quantitative studies on the conservative treatment of forearm instability are lacking. The present study developed a finite element model of the forearm to investigate the contribution of the distal radioulnar joint stabilizer on forearm stability. The stabilizer was designed to provide stability between the radius and ulna. The forearm model with and without the stabilizer was tested using the pure transverse separation and radial pull test for the different ligament sectioned models. The percentage contribution of the stabilizer and ligament structures resisting the load on the forearm was estimated. For the transverse stability of the forearm, the central band resisted approximately 50% of the total transverse load. In the longitudinal instability, the interosseous membrane resisted approximately 70% of the axial load. With the stabilizer, models showed that the stabilizer provided the transverse stability and resisted almost 1/4 of the total transverse load in the ligament sectioned models. The stabilizer provided transverse stability and reduced the loading on the ligaments. We suggested that a stabilizer can be applied in the conservative management of patients who do not have the gross longitudinal instability with the interosseous membrane and the triangular fibrocartilage complex disruption.

Outcomes of the Adams-Berger Ligament Reconstruction for the Distal Radioulnar Joint Instability in 95 Consecutive Cases

Objective  The objective of this article is to evaluate the outcomes and complication rate for Adams-Berger anatomic reconstruction of the distal radioulnar joint (DRUJ), in addition, to determine the role of sigmoid notch anatomy on failure. Methods  We conducted a retrospective chart review to evaluate adult patients that had undergone reconstruction of the DRUJ for instability with the Adams-Berger procedure between 1998 and 2015 within our institution with > 24 months follow-up. Charts were reviewed for patient demographics, mechanism of injury, outcome, and complications. Results  Ninety-five wrists in 93 patients were included. Mean age at surgery was 37.3 years with 65.2 months follow-up. At the last follow-up, 90.8% had a stable DRUJ, 5.3% did not, and 3.4% had some laxity. Postoperatively, 75.9% described either no pain or mild pain. Grip strength increased while pronosupination decreased. Procedure success was 86.3%, as 12 patients underwent revision at 13.3 months postoperatively. Reconstructive failure was more common in females when an interference screw was utilized for tendon fixation. Age, timing of surgery, type of graft, sigmoid notch anatomy, and previous surgery did not affect revision or failure rate. Conclusion  Our findings demonstrate that Adams-Berger reconstruction of the DRUJ provides reliable long-term results with an overall success of 86% at > 5 years follow-up. Level of evidence/Type of study  This is a Level IV, therapeutic study.

Level of evidence in wrist ligament repair and reconstruction research: a systematic review

There have been numerous studies on surgery of wrist ligament injuries, but a quick assessment reveals few with a high level of evidence (LoE). The primary aim of this study was to categorize the study type and LoE of studies on repair and reconstruction of the scapholunate ligament, the lunotriquetral ligament and the triangular fibrocartilage complex by applying the LoE rating system proposed by the Oxford Centre for Evidence-Based Medicine. The secondary aims were to evaluate the journal- and geographic- distribution of the included studies.

An electronic literature search of articles published 1985–2016, in PubMed, Embase, and Cochrane Library was carried out in May 2016 and updated in April 2017. Therapeutic studies written in English were included. The PRISMA checklist guided the extraction and reporting of data.

A total of 1889 studies were analyzed, of which 362 were included. Three journals represented 40% of the included studies and American authors dominated.

Most studies (97%) had low LoE (IV-V). No studies of LoE I-II were found. There is insufficient evidence to recommend one technique over the other in terms of wrist ligament surgery in clinical practice. There is an immense lack of comparison studies with high level of evidence in the area of wrist ligament repair and reconstruction.

The status of triangular fibrocartilage complex after the union of distal radius fractures with internal plate fixation

PURPOSE

Distal radius fractures are associated with a high incidence of triangular fibrocartilage complex (TFCC) tears. This study aims to evaluate the status of TFCC after the healing of distal radius fractures, and its clinical significance.

METHODS

Wrist arthroscopies were performed on 43 distal radius fractures, with an average age of 54 years old.

RESULTS

Twenty-six complete tears and 15 partial healed tears were noted. Five out of eight patients with intact TFCC tears had neither signs nor symptoms, while eight patients with TFCC tears had no complaint. While no association was found between ulnar wrist pain and TFCC tears, there was association between DRUJ instability and TFCC tears and fovea tears. The function outcome did not differ with respect to the integrity of TFCC.

CONCLUSIONS

A large majority of TFCC tears remained unhealed after the union of distal radius fractures. However, not all patients with tear were symptomatic.

Techniques of Force and Pressure Measurement in the Small Joints of the Wrist

BACKGROUND

The alteration of forces across joints can result in instability and subsequent disability. Previous methods of force measurements such as pressure-sensitive films, load cells, and pressure-sensing transducers have been utilized to estimate biomechanical forces across joints and more recent studies have utilized a nondestructive method that allows for assessment of joint forces under ligamentous restraints.

METHODS

A comprehensive review of the literature was performed to explore the numerous biomechanical methods utilized to estimate intra-articular forces.

RESULTS

Methods of biomechanical force measurements in joints are reviewed.

CONCLUSIONS

Methods such as pressure-sensitive films, load cells, and pressure-sensing transducers require significant intra-articular disruption and thus may result in inaccurate measurements, especially in small joints such as those within the wrist and hand. Non-destructive methods of joint force measurements either utilizing distraction-based joint reaction force methods or finite element analysis may offer a more accurate assessment; however, given their recent inception, further studies are needed to improve and validate their use.

Outcomes of Isolated Radial Osteotomy for Volar Distal Radioulnar Joint Instability Following Radial Malunion in Children

PURPOSE

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.

METHODS

The charts of 7 children (2 boys and 5 girls) treated with corrective radial osteotomy for volar DRUJ instability after a radius fracture or deformity were reviewed. Demographic, diagnostic, treatment, and complication information was collected for each patient. Radiographs at initial injury, fracture union, diagnosis of DRUJ instability, and final follow-up were reviewed for radiographic measurements of radial deformity and subsequent correction.

RESULTS

Fractures included 4 distal radius, 2 proximal radius, and 1 plastic deformation of the radial shaft. Volar DRUJ instability was diagnosed an average of 2.7 years (range, 1-6 years) after fracture at an average age of 13.6 years (range, 12-17 years). Two of 7 patients had persistent symptoms despite having undergone previous soft tissue surgery for DRUJ instability. Radial osteotomy was performed on all patients (3 dorsal and 4 volar approaches), with an average sagittal plane correction of 23° ± 10° (range, 14° to 40°). Osteotomy site varied (3 proximal third, 1 middle third, and 3 distal third) based on the apex of maximal deformity. Patients were observed an average of 2.3 years (range, 1.0-5.7 years). At final follow-up, all patients had a stable DRUJ and no patient required soft tissue stabilization.

CONCLUSIONS

Apex volar malunion of radial fractures may result in volar instability of the DRUJ. Radial osteotomy restored the normal apex dorsal radial bow and effectively stabilized the DRUJ without the need for soft tissue repair. Osteotomy should be tailored to the specific site of radiographic deformity.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Distal radio-ulnar implant arthroplasty: a systematic review

The use of implant arthroplasty in the hand and wrist is increasing, often with little evidence of outcomes in the literature. We therefore undertook a systematic review of the outcomes of distal radio-ulnar joint arthroplasties following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Papers were assessed for outcomes, implant survival and methodological quality. Fourteen papers assessed ulna head replacements. The implant survival rate was 93% at a mean follow-up of 45 months. One paper assessed a partial ulna head replacement. Fourteen papers assessed total distal radio-ulnar joint replacements; all but two used the Aptis prosthesis. These implants had a survival rate of 97% at a mean of 56 months. Complications rates were 28% in both groups, and many were major. Although these data are impressive, worldwide there are many more implants placed and not followed up. All studies were level IV and V studies with low Coleman scores. This systematic review demonstrates that implant arthroplasty for the distal radio-ulnar joint has produced acceptable results in small numbers of patients. Whilst these short term outcomes are encouraging, the indications should be carefully considered and there should be proper consideration of the potential for later failure.

LEVEL OF EVIDENCE

III.

Rehabilitation of distal radioulnar joint instability

Distal radioulnar joint (DRUJ) instabilities are common and often combined with other injuries of the interosseous membrane and/or the proximal radioulnar joint. Once they are diagnosed and the treatment is chosen, physiotherapists have limited choices due to the lack of validated protocols. The benefits of proprioception and neuromuscular rehabilitation have been brought to light for the shoulder, knee and ankle joints, among others. However, no program has been described for the DRUJ. The purpose of this article is to study the muscular elements responsible for active DRUJ stability, and to propose a proprioceptive rehabilitation program suited to this condition.

Ultrasound imaging of the distal radioulnar joint: a new method to assess ulnar radial translation in forearm rotation

A cross-sectional reliability study was conducted with 23 normal participants to establish normal values, and the repeatability and validity of distal radioulnar joint translation measurements using ultrasound imaging. Static transverse images of maximal supination, neutral and maximal pronation were examined to assess translation, using a method consistent with the rheumatoid arthritis subluxation ratio. Translation while gripping a 1 kg weight in supinated and pronated positions was then compared with non-gripping translation. There was significantly more ulnar radial translation found with pronation than supination, when compared with neutral. Gripping in pronation did not produce statistically significant changes in translation, whereas the changes produced by gripping in supination were significant. Internal consistency was deemed very high and the rheumatoid arthritis subluxation ratio values measured using ultrasound imaging were consistent with previously documented values measured by computerized tomography. This study demonstrated that translational movement of the distal radioulnar joint can be reliably detected in healthy participants using ultrasound imaging. This may reduce dependency on other imaging modalities to diagnose distal radioulnar joint instability.

LEVEL OF EVIDENCE

2.

Treatment of symptomatic non-unions of the base of the ulnar styloid with plate osteosynthesis

The purpose of this prospective case series was to assess the efficacy of plate osteosynthesis using a low profile distal ulna plate for the management of persistently symptomatic non-unions of the base of the ulnar styloid. Six consecutive patients underwent resection of the non-union and plate osteosynthesis with a 2.0 mm distal ulna hook plate. Post-operative measurements of mean pain scores, QuickDASH scores, grip strength, and range of motion parameters showed significant improvements compared with the pre-operative values. No complications were reported at a mean follow-up of 25 months. The present study presents an alternative method for treating symptomatic ulnar styloid non-unions that provides stable fixation with low risk of implant removal.

LEVEL OF EVIDENCE

Therapeutic IV.

Casting and Splinting Management for Hand Injuries in the In-Season Contact Sport Athlete

Context:

Upper extremity injuries are extremely common in contact sports such as football, soccer, and lacrosse. The culture of competitive athletics provides an environment where hand injuries are frequently downplayed in an effort to prevent loss of game time. However, studies have shown that many sport-induced hand injuries do not actually require immediate surgical attention and can be safely treated through immobilization so that the athlete may complete the athletic season. In these cases, appropriate casting and splinting measures should be taken to ensure protection of the injured player and the other competitors without causing loss of game time.

Evidence Acquisition:

Articles published between 1976 and 2015 were reviewed to capture historical and current views on the treatment of hand injuries in the in-season athlete.

Study Design:

Clinical review.

Level of Evidence:

Level 5.

Results:

Although traditionally many sports-induced traumatic injuries to the hand held the potential to be season-ending injuries, experience has shown that in-season athletes do not necessarily need to lose game time to receive appropriate treatment. A thorough knowledge of converting everyday splints and casts into game day, sport-approved protective immobilization devices is key to safely allowing athletes with select injuries to play while injured.

Conclusion:

Protective techniques allow for maximum functionality during gameplay while safely and effectively protecting the injury from further trauma while bony healing takes place.

Topographic matching of distal radius and proximal fibula articular surface for distal radius osteoarticular reconstruction

During osteoarticular reconstruction of the distal radius with the proximal fibula, congruity between the two articular surfaces is an important factor in determining the quality of the outcome. In this study, a three-dimensional model and a coordinate transformation algorithm were developed on computed tomography scanning. Articular surface matching was performed and parameters for the optimal position were determined quantitatively. The mean radii of best-fit spheres of the articular surfaces of the distal radius and proximal fibula were compared quantitatively. The radial inclination and volar tilt following reconstruction by an ipsilateral fibula graft, rather than the contralateral, best resembles the values of the native distal radius. Additionally, the ipsilateral fibula graft reconstructed a larger proportion of the distal radius articular surface than did the contralateral. The ipsilateral proximal fibula graft provides a better match for the reconstruction of the distal radius articular surface than the contralateral, and the optimal position for graft placement is quantitatively determined.

The correlation of initial radiographic characteristics of distal radius fractures and injuries of the triangular fibrocartilage complex

Our purpose was to determine the correlation of initial radiographic parameters of a distal radius fracture with an injury of the triangular fibrocartilage complex. In a prospective study, 85 patients with surgically treated distal radius fractures were included. Wrist arthroscopy was used to identify and classify triangular fibrocartilage complex lesions. The initial radial length and angulation, dorsal angulation, ulnar variance and distal radioulnar distance were measured. Wrist arthroscopy identified a triangular fibrocartilage complex lesion in 45 patients. Statistical analysis did not identify a correlation with any single radiographic parameter of the distal radius fractures with the associated triangular fibrocartilage complex injuries. The initial radiograph of a distal radius fracture does not predict a triangular fibrocartilage complex injury.

LEVEL OF EVIDENCE

III.

In-vivo three-dimensional measurement of distal radioulnar joint translation in normal and clinically unstable populations

Assessment of distal radioulnar joint instability is clinically difficult and subjective. The distal radioulnar joint is postulated to 'tighten' in ulnar/radial deviation and pronation/supination. Using a rig, we measured mean distal radioulnar joint translation in neutral forearm rotation and neutral wrist radial and ulnar deviation, as well as extremes of wrist radial and ulnar deviation and forearm rotation. We tested the rig on ten cadaver forearms to validate the measurements we made. We tested 50 normal adults and 50 patients with clinical distal radioulnar joint instability. Distal radioulnar joint stability in men and women and on contralateral sides were comparable. Distal radioulnar joint translation decreased significantly with wrist radial and ulnar deviation and forearm pronation and supination, matching clinical practice and further validating the rig. The data in normal patients is comparable with previous computed tomography-based studies. Translation in all positions was statistically increased within the clinical instability group and did not cross-over with the normal ranges. Distal radioulnar joint translation is a physically measurable phenomenon. Our device appears to be a valid test of distal radioulnar joint translation, establishing normal data in vivo.

LEVEL OF EVIDENCE

III.

Effect of volar angulation of extra-articular distal radius fractures on distal radioulnar joint stability: a biomechanical study

The relationship between increased volar tilt of the distal radius and distal radioulnar joint stability was examined. Distal radioulnar joint stiffness was recorded at 10° intervals from 10° dorsal angulation to 20° of volar angulation from the anatomical position of the radius. Tests were performed with the intact radioulnar ligament and repeated after partial and then complete sectioning of the radioulnar ligament at the ulnar fovea. With the intact radioulnar ligament, distal radioulnar joint stiffness increased significantly at 10° and 20° of volar angulation. Partial sectioning of the radioulnar ligament resulted in an approximate 10% decrease of distal radioulnar joint stiffness compared with the intact state, but distal radioulnar joint stiffness still increased significantly with greater volar tilt. Complete sectioning of the radioulnar ligament significantly decreased distal radioulnar joint stiffness, and increasing the volar tilt did not result in increased distal radioulnar joint stiffness. These results suggest that volar angulation deformities of the distal radius should be corrected to 10° of volar tilt when the triangular fibrocartilage complex is intact. Level of evidence: N/A.

Surgical treatment of acute distal radioulnar joint instability associated with distal radius fractures

This study investigates the question of whether open repair of acute distal radioulnar joint instability at the time of volar plating of distal radius fractures would enable early mobilization of the wrist without the risk of distal radioulnar joint instability. We evaluated 29 patients of mean age 53 years with a distal radius fracture and acute distal radioulnar joint instability who underwent volar plating of the radius combined with surgical repair of the triangular fibrocartilage complex or an ulnar styloid base fracture, followed by active motion exercise of the wrist at 1 week after surgery. At 1 year after treatment, all patients had a stable distal radioulnar joint and grip strength averaged 90% of the normal side. This study demonstrates that surgical repair of the triangular fibrocartilage complex or ulnar styloid fracture followed by early mobilization did not result in distal radioulnar joint instability, and suggests that the surgical treatment of distal radioulnar joint instability may permit early mobilization of the wrist in patients who are considered suitable for rapid rehabilitation after surgery. Type of study: Therapeutic Level IV.

Distal Oblique Bundle Reinforcement for Treatment of DRUJ Instability

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.

The biomechanical and functional relationships of the proximal radioulnar joint, distal radioulnar joint, and interosseous ligament

This biomechanical study assessed integrated function of the proximal radioulnar joint (PRUJ), interosseous ligament (IOL), and distal radioulnar joint (DRUJ). Tekscan™ pressure sensors were inserted into the DRUJ and PRUJ of 15 cadaveric specimens. MicroStrain(®) sensors were mounted onto the IOL on nine of these specimens. A customized biomechanical jig was used to apply axial loads and take measurements through pronosupination. The PRUJ, IOL, and DRUJ were shown to function as an integrated osseoligamentous system distributing applied load. The PRUJ has transmitted pressure profiles similar to those of the DRUJ. Different IOL components support loading at different stages of pronosupination. The IOL is lax during pronation. Mid-IOL tension peaks in the midrange of forearm rotation; distal-IOL tension peaks in supination. Axial loading consistently increases IOL strain in a non-linear fashion. There are clinical implications of this work: disease or surgical modification of any of these structures may compromise normal biomechanics and function.

Management of complications of forearm fractures

Forearm fractures may be complicated by the disruption of the distal radioulnar, proximal radioulnar, or radiocapitellar joints. The key principles in treating this unique subset of fractures include early recognition and management of the injury and restoration and maintenance of the anatomic alignment. This articles addresses radial diaphyseal fractures with distal radioulnar joint disruption, proximal ulnar fractures with radiocapitellar disruption, and disruption of the forearm longitudinal axis and how to properly recognize and manage these forearm fracture-dislocations.

Acute isolated volar dislocation of the distal radio-ulnar joint: case report and literature review

The acute isolated distal radio-ulnar (DRU) dislocation is a rare traumatic pathology and no consensus concerning its management has been established. This case report describes an acute isolated volar DRU dislocation in a 26-year-old patient. The authors propose, based on this case and after an exhaustive review of the literature, a non-operative management for these isolated and non-complicated dislocations.