Commentary: the effect of ulnar styloid fractures on patient-rated outcomes after volar locking plating of distal radius fractures

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.

Radial Sided Triangular Fibrocartilage Complex Tears: A Comprehensive Review

When evaluating the available literature on the diagnosis and management of triangular fibrocartilage complex tears (TFCC), ulnar tears comprise the major focus of TFCC literature. Radial-sided (Class 1D) tears are seldom researched or discussed. The purpose of this study was to review the methods for identifying and treating radial-sided TFCC lesions, by examining the anatomy of the TFCC, the pathology of its radial portion, diagnostic techniques, and both surgical and nonoperative treatments. The avascular nature of the radial TFCC may influence its healing potential. Magnetic resonance arthrogram is the gold standard for non-invasively diagnosing a radial-sided tear. Non-operative management should be exhausted prior to surgical intervention, which commonly involves an inside-out repair involving radial trans-osseous sutures. Still, the literature is limited by patient sample size and therefore requires a greater population of class 1-D tears to confirm optimal diagnostic and treatment methods.

Distal radioulnar joint instability: Diagnosis and treatment of acute and chronic lesions

Distal radioulnar joint instability is a common clinical condition that can be either acute or chronic. Its management requires extensive knowledge of all the anatomical structures around the wrist area. The clinical examination must identify all damaged structures in order to define a customized reconstruction strategy. The aim of treatment is to prevent the development of chronic instability and/or arthritic lesions, which can only be treated with palliative surgery. Distal radioulnar instability is complex. Its management shares similarities with that of knee instability, with a wide range of conditions ranging from a sprain with isolated ligament tear to complex dislocation in which multiple ligaments are torn. In particular, the triangular fibrocartilage complex, which is a pillar of distal radioulnar joint stability, is not the sole stabilizer of this joint. The treatment strategy is not as simple as just reattaching this ligament to treat all of the acute and chronic clinical signs. The goal of the present study is to describe the various structures and possible lesions in this joint and then how to repair them. The diagnostic and therapeutic difficulties justify treatment at a specialized center.

Ulnar shortening osteotomy for posttraumatic ulnar impaction syndrome in adolescent (younger than 18 years) - Based on the Cha & Shin assessment

PURPOSE

We performed ordinary ulnar shortening osteotomy (USO) in patients younger than 18 years old with secondary ulnar impaction syndrome (UIS) after traumatic events. Here, we report the clinical and radiologic outcomes with a review of the previous literature through a retrospective case series.

METHODS

Twenty-two adolescents treated by USOs from 2006 to 2018 were investigated. The amount of shortening was classified into three categories. The first category was for a still open physis on the medial half of the radius in those younger than 15. In this category, we osteotomized the ulna for the physis level to be left neutral or negative by 1-2 mm. The second category had no growth potency in the radius. If the patient was younger than 15, we considered only residual growth of the ulna, thus performing USO for the ordinary UV to be negative by 2-3 mm. For patients aged 15-18 years old, if growth potency was nearly absent in the ulna, we performed traditional USO with a neutral ulnar variance (UV).

RESULTS

Categories 1, 2, and 3 for the amount of USO were determined for 4, 4, and 14 patients, respectively. All USOs properly healed without substantial complications. The mean preoperative UV was 2.91 mm, and the final value decreased to 0.23 with statistical significance (p < 0.001). The range of wrist motion was improved after USO from 133.86° and 132.73° to 154.77° and 160.68° (all, p < 0.001 in flexion-extension and pronation-supination arcs, respectively). The preoperative VAS and MMWS scores also improved from 2.77 to 75.00 to 0.18 and 88.86, respectively, at the final follow-up (all, p < 0.001).

CONCLUSIONS

UIS in adolescent populations after trauma in their children/younger adolescents could be properly treated by USO. Even with an open physis at the ulna, neutral UVs could be achieved, and the clinical outcomes were satisfactory. However, long-term follow-up is still needed regarding TFCC and DRUJ status.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Distal-Ulna Stump Stability: The Role of Distal Interosseous Membrane: Myth or Reality? Anatomical Research

BACKGROUND

Distal-ulna stump (DUS) instability often occurs when performing a distal radioulnar joint (DRUJ) arthroplasty. Recent studies suggest that the distal interosseous membrane (DIOM) reinforces the triangular fibrocartilage complex, providing additional stability to the DRUJ. The aim of this study was to determine whether the DIOM stabilizes the ulnar stump.

METHODS

Twenty fresh-frozen random forearms were dissected. The presence of a distal oblique bundle (DOB) was recorded and measured. The radius was fixed to a vise and the ulna kept free. The DRUJ was fixed with a lag screw. A bone slice was removed by transverse ulna osteotomies 10 and 15 mm proximal to the DRUJ. A 10-N force was applied to the ulna in dorsal and volar directions. Displacements were measured. The DIOM was then transected, and maneuvers and measurements were repeated and compared.

RESULTS

A distinct distal membrane was present in 70% and a cord-like DOB in 30%. The mean length was 29 mm. Its origin was proximal to the sigmoid notch; its insertion was on the distal third of the ulna, at its lateral border. This attachment is comprised between 39 and 48 mm proximal to the ulnocarpal joint. Initial displacements averaged 22 mm dorsally and 13 mm volarly. After DIOM transection, ulnar translocation increased to 31 mm dorsally and 19 mm volarly.

CONCLUSION

In DRUJ arthroplasties, the DIOM does not appear to be a stabilizer of the DUS beneath a useful threshold. Its retaining effect occurs only after an initial 22-mm dorsal displacement, which we consider not clinically admissible. Therefore, in DRUJ arthroplasties, some augmentation might be advisable.

Intraoperative evaluation of DRUJ instability through dorsal stress radiography in distal radius fractures

INTRODUCTION

Certain type of injury of the triangular fibrocartilage complex associated with distal radius fracture can result in distal radioulnar joint instability (DRUJ). Untreated DRUJ instability may lead to poor result in the treatment of acute distal radius fractures. The aim of this study was to evaluate DRUJ instability in distal radius fractures through dorsal stress radiography comparing the affected and unaffected wrists intraoperatively.

MATERIALS AND METHODS

49 patients with a distal radius fracture who were operatively treated with a volar locking plate were included. Dorsal stress radiography was used to evaluate both affected and unaffected wrists peri-operatively to detect DRUJ instability. Under general anesthesia, a dorsal stress test was performed on the unaffected wrist. Additionally, after fixation of the affected wrist, a dorsal stress test was performed. The ulnar translation ratio (UTR) was measured through the dorsal stress radiograph. Arthroscopic examination was performed on all affected wrists according to Palmer's and Atzei classification.

RESULTS

The UTR of the affected wrist and the TFCC injury Palmer-type IB tendency were positively correlated (odds ratio: 1.18, p-value: 0.002). Additionally, as the UTR difference between the affected and unaffected wrists enlarged, it revealed a significant DRUJ instability tendency due to Palmer-type IB TFCC injury (p-value: 0.000006, Wilcoxon rank-sum test).

CONCLUSIONS

Dorsal stress radiography is a reliable, simple procedure to evaluate DRUJ instability intraoperatively. UTR value from dorsal stress radiography could be useful for evaluating DRUJ instability associated with distal radius fracture.

Operative Stabilization of Distal Radius Fractures Presenting With Ulnar Head Subluxation/Dislocation Addresses Distal Radioulnar Joint Instability Without Further Stabilization Procedures

OBJECTIVES

To determine the prevalence of ulnar head subluxation/dislocation in distal radius fracture and to discuss management, surgical outcomes, and relevant anatomy.

SETTING

Urban tertiary care hospital.

PATIENTS/PARTICIPANTS

Two hundred seventy-one patients with displaced distal radius fractures undergoing surgical management were reviewed to determine the incidence of ulnar head subluxation or dislocation using the Mino criteria defined by Mino et al.

MAIN OUTCOMES

Postoperative computed tomography and radiographs were assessed for sigmoid notch and distal radioulnar joint (DRUJ) reduction and fracture healing. Range of motion, functional limitation, and pain were documented at final outcome.

RESULTS

Of the 271 cases, there were 8 cases of prereduction DRUJ subluxation/dislocation, including 2 frank dislocations and 6 subluxations (2.95%). All were treated with open reduction and internal fixation (ORIF) of the distal radius with a volar locked plate. In addition, 1 patient underwent ORIF of an associated distal ulnar shaft fracture and another, who had a grade 1 open fracture over the distal ulna, underwent open TFCC repair. The remaining 6 patients had closed reduction of the DRUJ without further stabilizing procedures. All had stable DRUJ joints following ORIF, both intra-operatively and at final follow-up. All ulnar heads were located within the DRUJ on post-op computed tomography; using the more sensitive radioulnar ratio there was residual ulnar head subluxation in 5/8 patients. Range of motion and functional outcome were excellent at an average of 133 weeks postoperatively. The DRUJ was stable at long-term follow-up in all patients.

CONCLUSIONS

Ulnar head subluxation/dislocation is an uncommon injury in the setting of distal radius fracture. When present, it can usually be treated effectively with operative stabilization of the distal radius fracture without further stabilizing procedures.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Corrective osteotomy for malunion of distal diaphyseal/metaphyseal radius or ulna fracture affecting stability of the distal radioulnar joint

BACKGROUND

We postulated that residual distal radioulnar joint (DRUJ) instability after distal diaphyseal or metaphyseal fracture in the radius or ulna may occur due to malaligned or malunited bony structures as well as primary or secondary soft issue stabiliser. Here, we report the outcomes of corrective osteotomy in a retrospective study.

METHODS

Patients undergoing the osteotomy for DRUJ instability between March 2000 and February 2018 were included in the study. Thirteen patients were evaluated. The initial injury occurred at a mean age of 12.3 years and corrective osteotomy was performed at a mean age of 20.8 years. The mean follow-up period was 33.1 months. The male to female ratio was 8:5 and the corrected radius/ulna ratio was 11:2. DRUJ instability was diagnosed clinically and radiologically based on the stress/clunk test and the distance between the cortex of the radius, and the radioulnar ratio. All osteotomies in the radius and ulna were of the open wedge type and were performed using plates/screws.

RESULTS

The radioulnar ratio was significantly higher than the normal ratio (p < 0.001). All osteotomies healed well without any serious complications. The preoperative distance between the cortex of the radius and ulna was significantly decreased at the final follow-up, from 4.74 ± 0.82 to 1.16 ± 0.46 mm (p < 0.001). Positive findings of two instability tests were all converted to negative. The ranges of motion of the flexion-extension and pronation-supination arcs were significantly improved. Finally, preoperative VAS pain and DASH scores improved to 0.23 ± 0.44 and 3.92 ± 1.84, respectively (p < 0.001).

CONCLUSIONS

Malunited radius or ulna plays a role in DRUJ instability, affecting the bony geometry in terms of the relationship between the sigmoid notch and ulnar head. Treatment of malunion by corrective osteotomy represents a useful option for resolving instability.

LEVEL OF EVIDENCE

Level IV, Retrospective therapeutic study.

Distal Radius Fracture and the Distal Radioulnar Joint

In this article, we discuss the incidence and types of injuries to the distal radioulnar joint (DRUJ) that occur in the setting of a distal radius fracture. We review the anatomy of the distal radioulnar joint, which is critical to understanding its biomechanics, and how injury could cause symptomatic incongruency and instability. We highlight how patients with an injury to the distal radioulnar joint might present both at the time of injury and after treatment of a distal radius fracture, the appropriate workup, the available treatment options, and the evidence-based literature.

Distal radioulnar joint instability: current concepts of treatment

Distal radioulnar joint (DRUJ) instability is often an underestimated or missed lesion which may entail fatal consequences. The triangular fibrocartilage complex is a biomechanically very important stabilizer of the DRUJ and guarantees unrestricted range of motion of the forearm. To detect DRUJ instability a systematic examination is of uppermost importance. The contralateral healthy arm will be used for comparison during clinical examination. X-rays are required to exclude osseous lesions or deformities. Computed tomography of both wrists in neutral forearm rotation, supination, and pronation may be necessary to verify DRUJ instability in ambiguous situations. Following a systematic clinical examination wrist and DRUJ arthroscopy detects lesions definitely. Tears of the distal radioulnar ligaments which entail DRUJ instability should be repaired preferably anatomically. Ulnar-sided ligament ruptures which cause instability are detected more often than radial-sided ones. Osseous ligament avulsions are mostly refixated osteosynthetically. Ligamentous tears of the distal radioulnar ligaments may be reconstructed using anchor suture or transosseous refixation. Secondary procedures such as tendon transplants are necessary for anatomical reconstruction in cases of unrepairable ligament tears.

Prevalence of the distal oblique bundle of the interosseous membrane of the forearm: an anatomical study

A study was undertaken to examine the presence of the distal oblique bundle of the forearm in a large sample in order to describe its true prevalence. The study sample consisted of 200 cadaveric forearms. Fifteen were excluded due to defects in the distal interosseous membrane. In the remaining 185 specimens, the distal interosseous membrane was examined following removal of soft tissue, to determine whether a distal oblique bundle was present and whether there were connecting fibres to the distal radio-ulnar joint. The distal oblique bundle was observed in 53 specimens (29%). In 45 of these forearms (85%), one or more connecting fibres to the distal radio-ulnar joint were identified. The presence of a distal oblique bundle in 29% is less frequent than that reported in previous literature. The presence of the distal oblique bundle should be noted and may be of importance in the management of disorders of the distal radio-ulnar joint.

The value of computed tomography in detecting distal radioulnar joint instability after a distal radius fracture

This study evaluated the value of computed tomography scans for the diagnosis of distal radioulnar joint instability. A total of 46 patients, conservatively treated for a unilateral distal radius fracture, were evaluated. Clinical instability was tested using the stress test and clunk test. A computed tomography scan of both wrists was performed in pronation and supination. Two independent observers reviewed the computed tomography scans using: the radioulnar line, subluxation ratio, epicentre and radioulnar ratio methods. Radiological distal radioulnar joint instability was assessed by comparing the measurements of the injured wrist with those of the contralateral uninjured wrists. A total of 22 patients had clinical instability of whom 12 suffered from pain in the injured wrist. Distal radioulnar joint instability was diagnosed on computed tomography in 29 patients. Reliability analysis between clinical and radiological evaluations showed at best moderate, but generally poor agreement. The diagnostic ability of computed tomography for identifying distal radioulnar joint instability seems limited.

LEVEL OF EVIDENCE

IV.

Clinical DRUJ instability does not influence the long-term functional outcome of conservatively treated distal radius fractures

OBJECTIVE

The presence of distal radioulnar joint (DRUJ) instability remains often unnoticed initially, but may worsen functional outcome of distal radius fractures (DRF). The aim of this study was to evaluate the influence of concurring clinical DRUJ instability on the outcome of conservatively treated DRF.

METHODS

In a retrospective cohort study, all unilateral, conservatively treated DRF patients were invited for physical examination, CT scan of both wrists and filling out questionnaires. Static and dynamic DRUJ instability were clinically tested.

RESULTS

Forty-nine DRF patients with a mean follow-up of 4.2 years (SD 0.5) were assessed. Seventeen patients tested positive for DRUJ instability. No differences were found in baseline characteristics between the DRUJ stable and unstable group. Apart from wrist flexion, no statistical significant differences in outcome was found between patients with and without DRUJ instability.

CONCLUSION

The presence of clinical DRUJ instability does not seem to affect functional outcome of conservatively treated distal radius fractures at long-term follow-up.

Computed tomography for the detection of distal radioulnar joint instability: normal variation and reliability of four CT scoring systems in 46 patients

OBJECTIVES

The diagnosis of distal radioulnar joint (DRUJ) instability is clinically challenging. Computed tomography (CT) may aid in the diagnosis, but the reliability and normal variation for DRUJ translation on CT have not been established in detail. The aim of this study was to evaluate inter- and intraobserver agreement and normal ranges of CT scoring methods for determination of DRUJ translation in both posttraumatic and uninjured wrists.

MATERIALS AND METHODS

Patients with a conservatively treated, unilateral distal radius fracture were included. CT scans of both wrists were evaluated independently, by two readers using the radioulnar line method, subluxation ratio method, epicenter method and radioulnar ratio method. The inter- and intraobserver agreement was assessed and normal values were determined based on the uninjured wrists.

RESULTS

Ninety-two wrist CTs (mean age: 56.5 years, SD: 17.0, mean follow-up 4.2 years, SD: 0.5) were evaluated. Interobserver agreement was best for the epicenter method [ICC = 0.73, 95 % confidence interval (CI) 0.65-0.79]. Intraobserver agreement was almost perfect for the radioulnar line method (ICC = 0.82, 95 % CI 0.77-0.87). Each method showed a wide normal range for normal DRUJ translation. Normal range for the epicenter method is -0.35 to -0.06 in pronation and -0.11 to 0.19 in supination.

CONCLUSION

DRUJ translation on CT in pro- and supination can be reliably evaluated in both normal and posttraumatic wrists, however with large normal variation. The epicenter method seems the most reliable. Scanning of both wrists might be helpful to prevent the radiological overdiagnosis of instability.

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.

The impact of coronal alignment on distal radioulnar joint stability following distal radius fracture

PURPOSE

Shift of the distal fragment of a distal radius fracture (DRF) in the coronal plane (coronal shift) may compromise the contributions of the distal oblique bundle (DOB) of the interosseous membrane to distal radioulnar joint (DRUJ) stability. The purpose of the study was to test our hypothesis that coronal shift of the distal fragment would increase dorsal-volar DRUJ displacement in response to applied load.

METHODS

A distal radius osteotomy was performed proximal to the sigmoid notch base and the ulnar styloid was cut (to simulate triangular fibrocartilage complex detachment) in 10 cadaveric specimens. A volarly placed plate was used to shift the distal radius fragment radially in 2-mm increments. A mechanical testing apparatus applied a 20 N load to the distal fragment perpendicular to the volar cortex with the forearm in neutral, 60° pronation, and 60° supination. Dorsal-volar displacement of the radius relative to the fixed ulna was measured in the control state (DRF and ulnar styloid anatomically fixed) and in 3 positions (anatomical reduction, 2-mm coronal shift, 4-mm coronal shift) with ulnar styloid displacement. The specimens were dissected post hoc to evaluate for a distinct DOB (thickness, > 0.5 mm). Dorsal-volar DRUJ displacement was compared among testing and control states using analysis of variance.

RESULTS

In specimens with a distinct DOB, 2-mm coronal shift significantly increased dorsal-volar DRUJ displacement. However, there was no difference in DRUJ displacement between 4-mm coronal shift and control state. Coronal shift did not affect dorsal-volar DRUJ displacement in specimens without a distinct DOB.

CONCLUSIONS

In the setting of an ulnar styloid fracture, a 2-mm (but not a 4-mm) coronal shift of the DRF is associated with increased dorsal-volar DRUJ displacement in specimens with a distinct DOB, but not in specimens without a distinct DOB.

CLINICAL RELEVANCE

Awareness of the importance of coronal shift may aid in prevention of DRUJ instability associated with DRF, especially in patients with a DOB.

Influence of ulnar translation of the radial shaft in distal radius fracture on distal radioulnar joint instability

It has been reported that the distal interosseous membrane (DIOM) of the forearm constrains the dorsal dislocation of the distal radius. A residual ulnar translation deformity of the radial shaft in distal radius fractures has the potential to cause distal radioulnar joint (DRUJ) instability when triangular fibrocartilage complex (TFCC) injury is also present, because it may result in detensioning of the DIOM. Correction of ulnar translation of the radial shaft is critical because it restores DIOM tension, which then firmly holds the ulnar head in the concavity of the sigmoid notch.

Bilateral test for potential subluxation of the DRUJ

Untreated distal radioulnar joint (DRUJ) instability can lead to arthritis of the DRUJ. To date, however, the clinical determination of DRUJ instability still represents a challenge. We developed a new clinical test to determine its stability. This works by directly observing the ulnar head's dynamic behavior during active pro-supination or testing the DRUJ's static stability at different grades of rotation. With the test results, the examiner gains a better understanding of the ulna head's behavior during rotational movements and how that compares to that of the uninjured side.

Changes in length of the radioulnar ligament and distal oblique bundle after Colles' fracture

The purpose of this study was to investigate changes in length of the radioulnar ligament and distal oblique bundle (DOB) within the distal interosseous membrane after Colles' fracture and correlate the magnitude of the changes in length with clinical features. This study investigated 10 patients with malunion of a Colles' fracture. In three-dimensional computed tomography, the paths of the four limbs of the radioulnar ligament (superficial and deep, dorsal, and palmar limbs) and DOB were modelled and each path length was computed. Differences in length between the affected and contralateral unaffected side were calculated and correlated with the radiographic parameters of deformity on plain X-ray, subluxation of the DRUJ on CT, and limited range of forearm rotation in the clinical examination. In the malunited radius, the superficial and deep dorsal limbs of the radioulnar ligament were significantly elongated and DOB was significantly shortened compared with the contralateral side. These length changes correlated with radiographic radial shortening, subluxation of the DRUJ, and inversely correlated with limited range of forearm pronation. This study suggests that the dorsal radioulnar ligament would be overstretched and disrupted in Colles' fracture with severely increased radial shortening, producing laxity of the distal radioulnar joint that could negate limitation of pronation.

Treatment with or without internal fixation for ulnar styloid base fractures accompanied by distal radius fractures fixed with volar locking plate

The purpose of this study was to evaluate the treatment results, with and without internal fixation of ulnar styloid base fractures associated with acute distal radius fractures. A total of 48 patients were enrolled, including 20 patients treated by internal fixation (fixation group) and 28 treated without internal fixation (non-fixation group). The evaluated parameters were postoperative range of motion, grip strength, DASH score, and the presence or absence of ulnar wrist pain over time. The outcome was assessed as "excellent" in 15 patients of the fixation group and 21 patients of the non-fixation group, and "good" in five patients of the fixation group and seven patients of the non-fixation group. There were no significant differences in the clinical outcomes or any of the parameters at the final evaluation between the two groups. However, the grip strength was significantly better in the non-fixation group than in the fixation group until 12 weeks postoperatively. The overall clinical outcome was good in both groups, with no significant difference between the groups.

The distal interosseous membrane: current concepts in wrist anatomy and biomechanics

The distal interosseous membrane (DIOM) of the forearm acts as a secondary stabilizer of the distal radioulnar joint (DRUJ) when the dorsal and palmar radioulnar ligaments of the triangular fibrocartilage complex are cut. Recent anatomical studies revealed that thickness of the DIOM varies widely among specimens and the distal oblique bundle (DOB) exists within the DIOM in 40% of specimens. The DOB originates from the distal one-sixth of the ulnar shaft and runs distally to insert on the inferior rim of the sigmoid notch of the radius. The mean thickness of the DIOM without a DOB was 0.4 mm, which was significantly thinner than 1.2 mm with a DOB. Biomechanical studies have shown that the DOB is an isometric stabilizer of the forearm during pronosupination. The presence of a DOB was shown to have a significant impact on DRUJ stability. Innate DRUJ laxity in the neutral forearm position was greater in the group without a DOB than in the group with a DOB. Ulnar shortening with the osteotomy performed proximal to the attachment of the DIOM had a more favorable effect on stability of the DRUJ compared with the effect of distal osteotomy, especially in the presence of a DOB. The longitudinal resistance to ulnar shortening was significantly greater in proximal shortening than in distal shortening. It also suggested that the DIOM is of great importance in the management of concomitant ulnar-side injuries in distal radius fracture.

Clinical and non-clinical aspects of distal radioulnar joint instability

Untreated distal radioulnar joint (DRUJ) injuries can give rise to long lasting complaints. Although common, diagnosis and treatment of DRUJ injuries remains a challenge. The articulating anatomy of the distal radius and ulna, among others, enables an extensive range of forearm pronosupination movements. Stabilization of this joint is provided by both intrinsic and extrinsic stabilizers and the joint capsule. These structures transmit the load and prevent the DRUJ from luxation during movement. Several clinical tests have been suggested to determine static or dynamic DRUJ stability, but their predictive value is unclear. Radiologic evaluation of DRUJ instability begins with conventional radiographs in anterioposterior and true lateral view. If not conclusive, CT-scan seems to be the best additional modality to evaluate the osseous structures. MRI has proven to be more sensitive and specific for TFCC tears, potentially causing DRUJ instability. DRUJ instability may remain asymptomatic. Symptomatic DRUJ injuries treatment can be conservative or operative. Operative treatment should consist of restoration of osseous and ligamenteous anatomy. If not successful, salvage procedures can be performed to regain stability.

Management of the distal radioulnar joint and ulnar styloid fracture

Fractures of the distal radius and ulnar styloid have the potential to disturb the normal function of the distal radioulnar joint (DRUJ), resulting in loss of motion, pain, arthritis, or instability. The DRUJ can be adversely affected by several mechanisms, including intra-articular injury with step-off, shortening, and angulation of an extra-articular fracture; injury to the radioulnar ligaments; ulnar styloid avulsion fracture; and injury of secondary soft tissue stabilizers. This article discusses the management of the DRUJ and ulnar styloid fracture in the presence of a distal radius fracture.

Arthroscopic evaluation of the foveal attachment of the triangular fibrocartilage

Anatomical and biomechanical studies have highlighted the importance of the deep attachment of the TFCC for maintaining stability of the distal radioulnar joint (DRUJ). The standard arthroscopic assessment of the TFCC does not allow one to definitively determine whether the deep fibers are indeed intact, and establishing the diagnosis of a foveal detachment remains an exacting challenge. DRUJ arthroscopy is useful to assess the foveal fibers in any patient with DRUJ instability and can aid in the surgical decision making.

Distal radius instability and stiffness: common complications of distal radius fractures

Emphasis in the literature over the past hundred years regarding distal radius fracture management has been on restoration of anatomic radio-carpal alignment. Until the two most recent decades, little emphasis has been placed on the great morbidity and compromise to upper limb function associated with distal radio-ulna joint (DRUJ) pathology occurring with fractures of the distal radius. This article emphasizes that attention to restoration of anatomy of the DRUJ should be considered at least as important as that given to the radio-carpal relationship. This article also points out how stiffness of forearm rotation can result from a well-treated distal radius fracture and how this complication can be treated to restore healthy upper limb function.