The radioulnar ratio: a new method of quantifying distal radioulnar joint subluxation

Validating Clinical Distal Radioulnar Joint Examination With Radiographic Parameters

BACKGROUND

The purpose of this study was to quantify the in vivo displacement of bilateral distal radioulnar joints (DRUJs) in resisted pronosupination. We hypothesize that this will demonstrate no appreciable difference between the left and right DRUJ, thus validating the concept of using the uninjured wrist as a control for physical examination as well as dynamic imaging studies.

METHODS

Thirty-two participants without a history of wrist pathology underwent a dynamic computed tomography (CT) protocol evaluating bilateral forearm rotation in neutral forearm rotation, 60° pronation, and 60° supination, including maximal isometric muscle loading. The DRUJ alignment, specifically the absolute degree and direction of subluxation of the ulna relative to the sigmoid notch, was then assessed using a modification of the radioulnar line method.

RESULTS

There was no significant difference in the mean displacement when comparing the right and left sides in neutral, pronation, or supination. The mean displacement was also compared between male and female patients, and there was no statistically significant difference in absolute displacement in neutral (male 0.99 mm vs female 1.38 mm) or supination (male -0.57 mm vs female -0.23 mm). However, the difference in pronation was statistically significant (male 2.69 mm vs female 3.26 mm). Of the 192 sequences, the measurements of displacement of the authors were within 1 mm 86% of the time (166 of 192).

CONCLUSIONS

Dynamic CT of bilateral DRUJs in resisted pronation, supination, and neutral demonstrated symmetry between the right and left DRUJ, supporting the concept of using the contralateral side as a control to identify instability in an injured wrist.

Analyzing the reduction quality of the distal radioulnar joint after closed K-wire transfixation in a cadaver model: is supination or neutral position superior?

INTRODUCTION

Distal radioulnar joint (DRUJ) instabilities are challenging and their optimal treatment is controversial. In special cases or when reconstruction of the stabilizing triangular fibrocartilage complex (TFCC) fails, K-wire transfixation can be performed. However, no consensus has been reached regarding the rotational position of the forearm in which this should be done. Therefore, it was investigated whether anatomical reduction would best be achieved by transfixation in neutral position or supination of the forearm.

MATERIALS AND METHODS

Twelve cadaveric upper limbs were examined before dissection of the DRUJ stabilizing ligaments and after closed transfixation in both positions by C-arm cone-beam CT. Whether this was first done in neutral position or in supination was randomized. The change in the radioulnar ratio (RR) in percentage points (%points) was analyzed using Student's t-test. RR was used since it is a common and sensitive method to evaluate DRUJ reduction, expressing the ulnar head's position in the sigmoid notch as a length ratio.

RESULTS

The analysis showed an increased change in RR in neutral position with 5.4 ± 9.7%points compared to fixation in supination with 0.2 ± 16.1%points, yet this was not statistically significant (p = 0.404).

CONCLUSIONS

Neither position leads to a superior reduction in general. However, the result was slightly closer to the anatomical position in supination. Thus, transfixation of the DRUJ should be performed in the position in which reduction could best be achieved and based on these data, that tends to be in supination. Further studies are necessary to validate these findings and to identify influential factors.

Is pronator quadratus muscle repair required after anterior plate fixation for distal radial fractures? A prospective randomized comparative study

In this prospective, randomized comparative study in patients with distal radial fractures, we aimed to determine whether surgical repair of the superficial head after anterior locking plate fixation of the radius improves clinical or functional outcomes or both, and distal radioulnar joint stability. One hundred patients were randomized to undergo distal radial fixation with or without repair of the superficial head. Twenty-one patients were lost to follow-up, leaving a final sample of 79 patients. No differences were observed between the groups in functional scores or complication after operation. Surgical repair of the superficial head of the pronator quadratus muscle after osteosynthesis with an anterior locking plate for distal radial fractures does not appear to substantially contribute to preserving distal radioulnar joint stability or improving the consolidation process.Level of evidence: II.

Reliability and Validity Analysis of the Distal Radioulnar Joint Ballottement Test

PURPOSE

Triangular fibrocartilage complex injuries can cause distal radioulnar joint (DRUJ) instability, which can be evaluated clinically with the DRUJ ballottement test. However, the reliability and validity of the test are unclear. This study aimed to analyze the reliability and validity of the test using a tracking device on healthy participants and patients with triangular fibrocartilage complex injuries.

METHODS

In this cross-sectional study, three orthopedic hand surgeons performed the DRUJ ballottement test using a technique of holding the carpal bones to the radius on 25 healthy participants (50 hands; 10 men and 15 women; mean age, 33 years; range, 20-51 years) and eight patients with triangular fibrocartilage complex injuries (16 hands; six men and two women; mean age, 43 years; range, 27-59 years). We used a three-dimensional electromagnetic tracking device to quantify the movement of the DRUJ and verify the reliability and validity of the test.

RESULTS

The intrarater and interrater intraclass correlation coefficients for DRUJ movement were 0.77 and 0.61, respectively, and the kappa coefficient for grading of DRUJ instability was 0.79. The correlation coefficient between DRUJ movement measured using the tracking device and instability judged clinically was 0.77. A comparison of healthy participants and the patients showed significantly greater DRUJ movement in the patients.

CONCLUSIONS

The test showed substantial intrarater and interrater reliability for assessing DRUJ movement and instability. The significant positive correlation between DRUJ movement and instability indicates the concurrent validity of the test. Moreover, the test showed discriminative validity in identifying mild or moderate DRUJ instability.

CLINICAL RELEVANCE

The DRUJ ballottement test using the holding technique has a relatively high diagnostic accuracy and can be used to assess DRUJ instability.

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.

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.

Normal Values of Distal Radioulnar Joint Kinematics during a Dynamic Press Test

Background  Measurement of in vivo distal radioulnar joint (DRUJ) pathomechanics during simple activities can represent the disability experienced by patients and may be useful in diagnostics of DRUJ instability. A first step is to describe the physiological normal limits for DRUJ kinematics in a reproducible and precise test setup, which was the aim of this study. Methods  DRUJ kinematics were evaluated in 33 participants with dynamic radiostereometry (RSA) while performing a standardized press test examination. AutoRSA software was used for image analyses. Computed tomography (CT) forearm bone models were generated, and standardized anatomical axes were applied to estimate kinematic outcomes including, DRUJ translation, DRUJ position ratio, and changes in ulnar variance. Repeatability of dynamic RSA press test double examinations was evaluated to estimate the precision and intraclass correlation coefficient (ICC) test-retest agreement. Results  The maximum force during the press test was 6.0 kg (95% confidence interval [CI]: 5.1-6.9), which resulted in 4.7 mm (95% CI: 4.2-5.1) DRUJ translation, DRUJ position ratio of 0.40 (95% CI: 0.33-0.44), and increase in ulnar variance of 1.1 mm (95% CI: 1.0-1.2). The mean maximum DRUJ translation leveled off after a 5 kg force application. The DRUJ translation ICC coefficient was 0.93 within a prediction interval of ± 0.53mm. Conclusions  This clinical study demonstrates the normal values of DRUJ kinematics and reports excellent agreement and high precision of the press tests examination using an automated noninvasive dynamic RSA imaging method based on patient-specific CT bone models. The next step is the application of the method in patients with arthroscopic verified triangular fibrocartilage complex injuries. Level of Evidence  This is a Level IV, case series study.

Midterm Results of Arthroscopy-Assisted "Tent Form" Triangular Fibrocartilage Complex Repair With Dorsal Distal Radioulnar Joint Capsule Imbrication for Posttraumatic Chronic Distal Radioulnar Joint Instability

PURPOSE

To evaluate the outcomes of "tent form" triangular fibrocartilage complex (TFCC) repair combined with dorsal distal radioulnar joint (DRUJ) capsule imbrication for posttraumatic chronic DRUJ instability.

METHODS

All patients treated with arthroscopic "tent form" TFCC repair and DRUJ capsule imbrication from 2016 to 2019 were retrospectively reviewed. The inclusion criteria were symptomatic chronic DRUJ instability for >6 months and dorsal DRUJ subluxation on magnetic resonance imaging. The Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, grip strength, Modified Mayo Wrist Score, range of motion, and distal radioulnar joint stability were assessed for a minimum of 2 years postoperatively.

RESULTS

Thirty-eight patients were included in the final analysis. The average follow-up duration was 35.6 months (range, 24-48 months). The 24-month postoperative grip strengths and 3-dimensional motions of wrist were not significantly different from that of the nonoperated wrist. Compared with their preoperative status, Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, and Modified Mayo Wrist Score indicated the significant improvement with P values of .001, .001, and .002, respectively.

CONCLUSIONS

In chronic DRUJ instability with a loosening dorsal capsule, "tent form" TFCC transcapsular repair combined with DRUJ capsule imbrication restored the integrity of TFCC and dorsal DRUJ capsule and achieved a promising outcome. We recommend this procedure as an option of treatment for patients with posttraumatic chronic DRUJ instability.

LEVEL OF EVIDENCE

IV, case series.

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.

Morphologic Characteristics of the Sigmoid Notch of the Distal Radius for Patients With Peripheral Triangular Fibrocartilage Complex Tear

The distal radioulnar joint (DRUJ) is stabilized by the bony anatomy of the contact surfaces. The authors analyzed the morphologic characteristics and radiologic parameters at the sigmoid notch of patients with a peripheral triangular fibrocartilage complex (TFCC) tear compared with asymptomatic patients. Preoperative axial computed tomography scans were reviewed for 76 wrists with peripheral TFCC injuries, including foveal avulsion, and 76 wrists of age- and sex-matched control subjects. The authors used axial computed tomography scans of the DRUJ to classify the patients into 4 groups according to the type of sigmoid notch, namely, flat face, ski-slope, C-type, and S-type. They also measured the tilting angle, depth, width of the sigmoid notch, and radioulnar ratio (RUR). Statistical analyses were performed with the chi-square test or paired t test (P<.05). The mean proportions of flat face, ski-slope, C-type, and S-type sigmoid notches among patients with peripheral TFCC injuries were 42%, 22%, 29%, and 7%, respectively, whereas those for the control group were 33%, 1%, 65%, and 1%, respectively (P<.05). The tilting angle was lower (TFCC injury, 84.5°; control, 86.2°; P<.05) and the RUR was significantly higher (TFCC injury, 0.67; control, 0.56) in the TFCC group, particularly for men (P<.05). Depth (TFCC injury, 1.0 mm; control, 1.3 mm; P>.05) and width (TFCC injury, 14.8 mm; control, 14.5 mm; P>.05) were similar between the groups. Patients with ski-slope or dorsally tilted sigmoid notches may be at greater risk for peripheral TFCC injuries. [Orthopedics. 2021;44(6):e729-e734.].

Distal Radioulnar Joint Instability

Instability of the distal radioulnar joint is a source of ulnar-sided wrist pain and functional impairment. Symptomatic instability may present acutely, after a recent traumatic injury, or in a delayed fashion as chronic instability following a history of a traumatic event. A detailed understanding of the complex anatomy, biomechanics, and stabilizing structures of the distal radioulnar joint is important to evaluate and treat acute and chronic instability. This article describes the pathophysiology of distal radioulnar joint instability with attention to the anatomic structures involved and provides information about evaluation and treatment.

Distal Radioulnar Joint Instability and Associated Injuries: A Literature Review

The distal radioulnar joint (DRUJ) allows supination and pronation of the distal forearm and wrist, an integral motion in everyday human activity. DRUJ injury and chronic instability can be a significant source of morbidity in patients’ lives. Although often linked with distal radius fractures, DRUJ injury may occur in a variety of other upper extremity injuries, as well as an isolated pathology. Diagnosis of this injury requires the clinician to have a high index of suspicion and low threshold for clinical testing and further imaging of the DRUJ. The purpose of this article is to provide a review on DRUJ anatomy and biomechanics, to discuss common diagnostic and treatment modalities, and to identify common injuries associated with DRUJ instability.

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.

A new quantitative evaluation system for distal radioulnar joint instability using a three-dimensional electromagnetic sensor

BACKGROUND

The accurate assessment of distal radioulnar joint (DRUJ) instability is still challenging as there is no established objective evaluation method. This study aimed to develop a noninvasive measurement method using a three-dimensional electromagnetic sensor system (EMS) to quantitatively assess and characterize the normal DRUJ movement in healthy volunteers.

METHODS

The DRUJ movement was mimicked using both a block model and saw bone. Movement of the models was measured by EMS, and the accuracy and reproducibility of the measurements were assessed. In vivo measurement was performed in a sitting position with the elbow flexed and the forearm pronated. One sensor each was attached to the distal radial shaft and the ulnar head. The examiners fixed the distal radius and the carpal bones, moved the ulnar head from the dorsal to the volar side and measured the dorsovolar translation. The volar translation was measured by EMS and ultrasonography, and the correlation coefficient was calculated. The dorsovolar translation was evaluated in 14 healthy volunteers (7 men and 7 women) by three hand surgeons. The intraclass and inter-rater correlation coefficients (ICCs), the differences between the dominant and non-dominant sides and between men and women were assessed.

RESULTS

The accuracy and reproducibility assessment results of the EMS showed high accuracy and reproducibility. In the comparison between EMS and ultrasonography, the correlation coefficient was 0.920 (p = 0.16 × 10^-3). The ICC (1,5) for the intra-rater reliability was 0.856, and the ICC (2,5) for inter-rater reliability was 0.868. The mean ulnar head translation and difference between dominant and non-dominant sides were 6.00 ± 1.16 mm (mean ± SD) and - 0.12 ± 0.40 mm, respectively. There were no significant differences between any of the parameters.

CONCLUSIONS

A new measurement method using EMS could evaluate DRUJ movement with high accuracy, reproducibility, and intra- and inter-rater reliability. In healthy volunteers, the dorsovolar ulnar head translation was 6.00 mm. The difference between the dominant and non-dominant sides was < 1.0 mm with no significant difference. EMS provided an objective, non-invasive, real-time assessment of dynamic changes in the DRUJ. These findings could be useful in the treatment of patients with DRUJ instability.

Galeazzi fracture-dislocations: Long-term prognosis of the distal radioulnar joint

The aim of the present study was to evaluate long-term functional and radiographic outcome in the distal radioulnar joint (DRUJ) for Galeazzi fracture-dislocation after anatomic reduction and rigid fixation of the radius. Fourteen patients, with an average age of 38 years, presenting with Galeazzi fracture-dislocation treated by open reduction and internal fixation (ORIF) of the radius and closed reduction of the DRUJ were retrospectively evaluated, with a minimum follow-up of 6 years. At final evaluation (mean: 8 years), the DRUJ was objectively and subjectively evaluated for range of motion (RoM), grip strength, ballottement test, pain on axial loading, function on visual analog scale (VAS) and DASH score. Radiographs and dynamic CT scans were performed to screen for DRUJ instability and/or osteoarthritis. Six of the patients had a positive comparative ballottement test, but none reported pain during the maneuver. No significant differences in RoM were found between the injured and uninjured wrist. Mean grip strength in the injured wrist was 77% of the contralateral value. Mean pain on VAS was 0.6. Mean global function on VAS was 9. Mean DASH score was 3. Dynamic CT showed no clear subluxation in any of the patients, and none showed severe articular changes. Our findings suggest that long-term clinical and radiological prognosis for the DRUJ in Galeazzi lesions is favorable when adequate closed reduction of the ulna is achieved after anatomical ORIF of the radius. LEVEL OF EVIDENCE: IV. Therapeutic case series.

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 stability measured with radiostereometry during the piano key test

Distal radioulnar joint instability is difficult to grade by clinical examination and interobserver reliability is low. This study used a new and precise radiostereometry method for measurement of distal radioulnar joint translation. Eight human donor arms were positioned in a custom-made fixture and a standardized piano key test was done with pressure on the ulnar head. Examination was done before and after dividing the styloid and foveal insertions of the triangular fibrocartilage complex. In the intact wrists, the piano key test induced a mean 1.36 mm translation of the ulnar head, which increased statistically significantly to 1.96 mm after a lesion of the styloid ligament insertion and to 2.3 mm after combined lesions of the styloid and foveal ligament insertions. This experimental cadaver study demonstrates a radiological method for precise quantification of distal radioulnar joint stability after different grades of triangular fibrocartilage complex injury.

Instability in the Setting of Distal Radius Fractures: Diagnosis, Evaluation, and Treatment

Distal radius fractures with severe displacement or concomitant triangular fibrocartilage complex tears may be accompanied by distal radioulnar joint instability. Clinicians should examine the distal radioulnar joint closely when managing wrist fractures and treat coexisting instability appropriately. Chronic instability from distal radius malunion may require osteotomy or radioulnar ligament reconstruction. With proper management, most patients recover forearm stability and rotational motion after distal radius fracture.

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.

Reliability of the Dorsal Tangential View in Assessment of Distal Radioulnar Joint Reduction in the Neutral, Pronated, and Supinated Positions in a Cadaver Model

PURPOSE

Intraoperative assessment of distal radioulnar joint (DRUJ) alignment is often based on lateral radiographs whose interpretation is dependent upon positioning the forearm in neutral rotation. The dorsal tangential view (DTV) is a near-axial view of the dorsal wrist used in assessing dorsal screw penetration during radius fixation. The purpose of this study was to determine whether the DTV can also reliably assess DRUJ alignment in multiple forearm positions.

METHODS

Four transhumeral cadaveric specimens were used to simulate an unstable DRUJ. The stabilizing soft tissue structures of the DRUJ were sectioned. Fluoroscopic DTV images were obtained with the DRUJ of each specimen held in 5 positions: dorsally dislocated, dorsally subluxated, reduced, volarly subluxated, and volarly dislocated. In each position, images were taken with the forearm in neutral rotation, full pronation, and full supination. Three observers independently assessed DRUJ position on DTV images. Intra- and interobserver reliability were assessed in each forearm position.

RESULTS

Observers correctly identified DRUJ position as reduced, volarly malreduced, or dorsally malreduced on 94% of the DTV images (97%, 95%, and 92% in the neutral, supinated, and pronated forearm positions, respectively). Weighted kappa values for intraobserver reliability were 0.965, 0.964, and 0.965 for the 3 observers. The mean kappas for intraobserver reliability were 1.000, 0.967, and 0.930 with the forearm in neutral, supinated, and pronated positions, respectively. Weighted kappa values for interobserver reliability between paired observers were 0.948, 0.912, and 0.929. The mean kappa for interobserver reliability was 0.926, 0.931, and 0.930 for the forearm in neutral, supinated, and pronated positions, respectively.

CONCLUSIONS

The DTV reliably demonstrated the position of the DRUJ independent of forearm rotation in a cadaveric model.

CLINICAL RELEVANCE

Surgeons may consider the DTV as another tool for fluoroscopic verification of the DRUJ reduction in the operating room or clinic.

Evaluation of radiological instability signs in the distal radioulnar joint in children and adolescents with arthroscopically-verified TFCC tears

INTRODUCTION

Recent reports in the adult literature reported the use of standardized radiographic measurement techniques to determine distal radioulnar joint (DRUJ) instability. The aim of this study was to evaluate the efficacy and accuracy of (1) the MRI-based modified radioulnar ratio technique and (2) the pisoscaphoid (PiSca) and radioulnar (RaUl) distances in true lateral radiographs in children and adolescents with arthroscopically-verified TFCC tears.

MATERIALS AND METHODS

We retrospectively assessed lateral wrist radiographs and axial MRI sequences of 18 adolescent patients (22 wrists) who had arthroscopically-confirmed TFCC tears and compared them to similar imaging of a control group of 28 healthy patients (28 wrists). Three raters assessed the images twice in a 2-week interval. Intraclass correlation coefficients (ICCs), unifactorial ANOVA, and ROC analysis were performed with regards to the different radiographic variables.

RESULTS

The interrater ICCs were almost perfect for all measurements except RaUl1, which showed a substantial agreement (0.751) among the three observers. The intrarater ICCs were almost perfect when measuring PiSca and MRI, and substantial to almost perfect for RaUl. Pearson's correlation showed a moderate, positive correlation between PiSca and RaUl distances (r = 0.608; p < 0.001), and a moderate, negative correlation between RaUl distance and MRI shift (r = - 0.486; p = 0.010). When the three core groups (peripheral, central tear, controls) were compared to each other regarding the radiographic instability parameters, only the MRI shift revealed a statistically significant difference (p = 0.003). Comparisons revealed significant differences between patients and controls (p = 0.004) and peripheral tears vs. controls (p = 0.001 and p = 0.010). The ROC analysis revealed a significant AUC only for the MRI (AuC 0.787 and p = 0.002).

CONCLUSIONS

Children and adolescents with peripheral TFCC tears showed significantly increased instability parameters in MRI compared to controls. These measurement techniques are no replacement for a thorough clinical examination but may be helpful for indicating diagnostic wrist arthroscopy in ambiguous cases.

LEVEL OF EVIDENCE

Level III; Diagnostic.

Distal radioulnar joint instability with three different injury patterns assessed by three-dimensional C-arm scans: a cadaveric study

The aim of this study was to establish a radiographic method for detecting distal radioulnar joint instability intraoperatively. We created three successive instabilities in 12 intact Thiel-fixed upper limb specimens: lesion of the triangular fibrocartilage complex, Galeazzi injury and Essex-Lopresti injury. We made three-dimensional scans of the wrists in pronation and supination with a mobile C-arm. We used four validated measurement methods to quantify ulnar migration in the standard axial planes: the radioulnar line method, the subluxation ratio method, the epicentre method and the radioulnar ratio method. All types of instability showed significantly increased migration of the ulna compared with the control group. The subluxation ratio and the radioulnar ratio methods showed the highest sensitivity and specificity in detecting the instabilities. We conclude that these two methods are feasible for radiographically assessing distal radioulnar joint instability. Instability may be assumed if the migration of the ulna in the sigmoid notch is at least 45% of the length of the sigmoid notch, in which case wire transfixation of the distal radioulnar joint is advised.

[Radiology of the distal radioulnar joint and the ulnocarpal complex]

X-ray images exposed in neutral position and radiocarpally centred are essential in imaging of the distal radioulnar joint (DRUJ). The anatomic orientation of the DRUJ is favourable for acquiring transaxial scans to display its anatomy, subtle derangements, osteoarthritis and intra-articular fractures free from superpositions. The triangular fibrocartilage complex (TFCC) is the most important stabilizer of the DRUJ. Provided that a focused clinical indication is given, high-resolution images are acquired, and an intra-venous or intra-articular contrast-agent is applied, all TFCC structures and destabilizing lesions can be displayed with the use of CT and MRI.

A Novel Technique to Assess Distal Radioulnar Joint Stability Using Increasing Torque

Background  Previous studies on computed tomography (CT) in patients with a suspected triangular fibrocartilage complex (TFCC) injury have not been successful in assessing distal radioulnar joint (DRUJ) laxity. The aim of this study was to develop a novel servomotor-driven device for the assessment of DRUJ by applying increasing torque to the DRUJ in pronation and supination. Methods  A custom-built device was designed to function during four-dimensional (4D) CT of the wrist. A torque meter, positioned between the incoming hand holder, and a direct current (DC) servomotor were used for angular positioning and for applying rotational force to the patient's arm. A total of 110 healthy participants were recruited to gather reference values for the range of motion (ROM), maximum torque in neutral and supinated/pronated position, and the ability to withstand an increasing, device-generated torque in these positions. The device was also used during 4D DRUJ CT in five patients with suspected TFCC injuries. Results  A gender- and age-relevant reference chart for ROM and torque was created. Men showed a tendency (ns) toward having a larger ROM and increasing strength with increasing age, whereas women showed the opposite. Also, the dominant hand showed a tendency toward having a larger ROM and being stronger than the nondominant hand (ns). A smaller cohort of patients ( n  = 5) with suspected TFCC injuries showed a significantly decreased ability to withstand increasing torque in both supination (2.1 ± 0.3 vs. 3.1 ± 0.2 s; p  < 0.005) and pronation (2.3 ± 0.5 vs. 3.1 ± 0.4 s; p  < 0.0005) and also showed a clear laxity on real-time 4D CT image sequences. Decreased strength at all positions was also found (average 74% decrease compared to noninjured side). Conclusion  Reference values for torque strength and ability to withstand increasing torque can be used clinically in the assessment of patients with symptoms that could represent ligamentous injuries to the TFCC. The ability to use the device during CT enables radiographic evaluation of instability during increasing torque. Level of Evidence This is a Level II study.

Quantitative assessment of distal radioulnar joint stability with pressure-monitor ultrasonography

Background

Diagnosing distal radioulnar joint (DRUJ) instability remains a challenge as it relies on physical examination. To quantitatively assess DRUJ stability, a pressure-monitor ultrasound system was developed. The objective of this study was to evaluate the force-displacement relationship of DRUJ in normal subjects.

Methods

Nine wrists of 9 asymptomatic volunteers were evaluated. The pressure-monitor ultrasound system was developed to apply pressure to the tissue with a pre-determined cycle and displacement of the transducer. Each subject was imaged sitting with the elbow flexed and forearm pronated. The dorsal surface of the distal radius and the center of the ulnar head were displayed at DRUJ level. The pressure toward palmar direction was applied to the distal ulna with different levels of transducer displacements, i.e., 1 mm, 2 mm, and 3 mm. The distance between the dorsal surface of the ulnar head and the dorsal surface of the distal radius was measured. The first measurement was performed at the initial position, and the second measurement was performed when the transducer pressed down the ulna to the degree that the ulnar head had shifted to the most palmar position. At the same time, the pressure to the transducer was measured. The changes of radioulnar distance (=the measurement at the most palmar position—the measurement at the initial position) and pressure, and pressure/distance ratio were compared among the different transducer displacements.

Results

The pressure was significantly increased as the transducer displacement became larger (P < 0.01). The changes of radioulnar distance were smaller in the 1 mm displacement condition compared to the 2 and 3 mm displacement conditions (P < 0.05). The pressure/distance ratio was larger in the 1 mm displacement condition compared to the 2 and 3 mm displacement conditions (P < 0.05).

Conclusions

A method to assess DRUJ stability by measuring changes in radioulnar distance and force application was developed. It was found that the application of 2 mm displacement and 200 g force was the critical stress for the capsuloligamentous structures to start stabilizing DRUJ. This methodology and the indices may be clinically useful to investigate the mechanical properties of patients with DRUJ instability.

The Acutely Injured Wrist

Wrist traumas are a frequent clinical emergency for which instrumental imaging assessment is required. The purpose of this article is to review the role of imaging assessment of traumatic wrist injuries, with particular reference to fractures and associated lesions.

The effects of incremental ulnar styloid osteotomies on distal radioulnar joint stability: a biomechanical cadaveric study

The purpose of this study was to systematically quantify distal radioulnar joint stability with a cadaveric model, using radiographic and joint contact force measurements. Six fresh-frozen cadavers underwent sequential ulnar styloid osteotomies. Posteroanterior and lateral stress radiographs were obtained and joint contact forces and areas were measured. Posteroanterior radiographs showed a significant increase in the distal radioulnar joint gap after osteotomy of the base of the ulnar styloid. Contact force and contact area measurements were not significantly different. We conclude that fractures that involve the ulnar styloid base should be considered for operative fixation when carrying out open reduction and internal fixation of fractures of the distal radius.

Dorsal Lunate Facet Fracture Reduction Using a Bone Reduction Forceps

Background  The dorsal lunate facet fragment represents part of a complex articular injury of the distal radius and is challenging to reduce through a standard volar approach. We propose reduction through a standard volar approach and intraoperative dorsal lunate facet reduction using a bone forceps. To evaluate the postoperative reduction, we used computed tomography (CT) scan. Methods  We retrospectively included 60 patients with a median follow-up of 44 weeks. Fracture reduction was evaluated using pre- and direct postoperative CT scans of the wrist, measuring the articular gap and step of the sigmoid notch. The range of motion was evaluated clinically by the treating physician. Bivariate analysis was performed to compare pre- and postoperative radiographic measurements and to compare wrist range of motion. Results  When comparing the injured with the uninjured wrist, there was a significant difference in flexion, extension, pronation, and supination. In 87% of the patients, there was complete radiographic reduction of the fracture. Conclusion  This study shows that dorsal ulnar lunate facet fracture fragments in distal radius fractures can be reduced through a standard volar approach with the help of an intraoperative bone reduction forceps. Using wrist CT, we showed that 87% of the patients with a dorsal ulnar lunate facet fragment had a postoperative articular step or gap of <1 mm. Level of Evidence : This is a level IV, therapeutic study.

Assessment of Distal Radioulnar Joint Stability After Reconstruction With the Brachioradialis Wrap

BACKGROUND

The brachioradialis (BR) wrap technique is an option to restore the stability of the distal radioulnar joint (DRUJ). The technique capitalizes on the BR's advantageous insertion point on the radial styloid and the ability of the BR to be harvested with minimal to no deficit. The tendon can then be wrapped around the radius and ulna, tunneling under the pronator quadratus and extensor compartments and secured back into its insertion to provide stability. In this cadaveric study, we used micro-computed tomography (CT) to assess the stability restored by this procedure.

METHODS

Axial CT scans were taken of cadaveric specimens (n = 10) in 3 different positions (neutral, 60° pronation, and 60° supination) to establish the baseline measurements of each DRUJ. Surgical disruption of the dorsal and volar ligaments of each DRUJ then simulated a destabilizing injury and the specimens were scanned again. The specimens then underwent the BR wrap procedure and were scanned once more. Degree of ulnar subluxation with respect to the Sigmoid notch was determined using the modified radioulnar line method.

RESULTS

The mean percentages of subluxation in the neutral position for the normal, injured, and reconstructed DRUJ were 22.4±4.9%, 56.2±12.9%, and 29.0±6.5%, respectively. In 60° pronation, these values were 15.4±4.7%, 53.5±15.0%, and 36.5±11.8%, respectively. In 60° supination, these values were 18.6±2.5%, 69.7±20.5%, and 31.9±8.7%, respectively.

CONCLUSIONS

Values differed significantly between normal and injured conditions in all positions. No significant difference was noted between normal and reconstructed conditions, suggesting reconstruction improves DRUJ biomechanics and more closely approximates normal stability.

The "second ulnar groove", a MRI sign suggesting a previous palmar luxation of the ulna at the distal radioulnar joint

INTRODUCTION

A cortical lined impaction on the radiodorsal side of the ulnar head may be at the origin of a "second ulnar groove" (SUG). The goal of this article is to illustrate this MRI sign, prompting for further investigation of the distal radioulnar joint (DRUJ). Hence associated soft tissue pathology may be detected, which may lead to instability.

MATERIAL AND METHODS

Following an anterior luxation of the ulna at the DRUJ a second cortical lined groove in a previously normal distal ulna was discovered. A data base review from January 2008 to August 2016 of the axial FS PD-TSE WI 1.5T MRI views of 1.716 patients was accomplished in search of similar bone defects.

RESULTS

Eight patients with previous severe wrist trauma presented with a similar posttraumatic ulnar bone defect. The preceding anterior luxation at the DRUJ was only clearly demonstrated in five patients. However, two more patients had a residual anterior subluxation. Different imaging techniques are discussed and the differential diagnosis is well illustrated.

CONCLUSIONS

The type of trauma, the specific location and the morphology of a second ulnar groove, all compatible with a sequel of an anterior luxation of the ulna at the DRUJ, should lead to a further specific clinical and MRI revaluation of the DRUJ.

Topographical Anatomy of the Distal Ulna Attachment of the Radioulnar Ligament

PURPOSE

The deep component of the distal radioulnar ligament provides translational stability and rotational guidance to the forearm. However, controversy exists regarding the importance of this structure as well as the nature of its attachment to the distal ulna. We aimed to evaluate the topographic anatomy of the distal ulna attachment of both the superficial and the deep components of the radioulnar ligament and to assess the relationship between its internal and its external morphometry.

METHODS

Thirteen human distal ulnae attached by ulnar part of the distal radioulnar ligament were scanned using micro-computed tomography and reconstructed in 3 dimensions. In addition, the distal radioulnar ligaments were examined under polarized light microscopy to determine the histological characteristics of collagen contained within the ligaments.

RESULTS

The deep limbs have broad marginal insertions at the fovea, whereas the superficial limbs have a circular and condensed insertion to the ulnar styloid. The center of the deep limb was separated from the base of the ulnar styloid by a mean of 2.0 ± 0.76 mm, and this distance was positively correlated with the width of the ulnar styloid. The mean distance between the center of the ulnar head and the center of the fovea was 2.4 ± 0.58 mm. The proportion of collagen type I was lower in the deep limb than in the superficial limb.

CONCLUSIONS

This new observation of the footprint of the radioulnar ligament in the distal ulna indicates that the deep limb may serve as an internal capsular ligament of the distal radioulnar joint, whereas the superficial limb as the external ligament.

CLINICAL RELEVANCE

Knowledge of the topographic anatomy of the radioulnar ligament's attachment to the distal ulna may provide a better understanding of distal radioulnar ligament-related pathologies.

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.

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.

A Biomechanical Perspective on Distal Radioulnar Joint Instability

Background The purpose of this article was to review the anatomy, kinematics of the distal radioulnar joint (DRUJ), and to discuss definition, classification, and diagnosis of DRUJ instability. Methods A biomechanical perspective on physical examination of DRUJ ballottement test was documented. Physiological dynamic DRUJ translation and differences of the translation following sequential ligament sectioning and changes in different forearm and wrist positions were demonstrated. The clinical significance of each ligament's contribution to joint stability in specific wrist positions was addressed. Conclusion Each ligament stabilizing the DRUJ contributed to joint stability depending on the direction (palmer or dorsal) and different positions of the wrist and forearm. DRUJ ballottement test in each wrist and forearm position may detect tears of specific ligament stabilizing the DRUJ.

Stability and Clinical Outcome after Reconstruction of Complete Triangular Fibrocartilage Disruption

Purpose Patients with symptomatic instability of the distal radioulnar joint (DRUJ) after traumatic complete disruption of the triangular fibrocartilage complex (TFC) are best treated by anatomic reconstruction of the TFC. Postoperative clinical results from the literature are known but the improvement of DRUJ instability remains still challenging to quantify. We recently published a reliable and validated method to measure the instability of the DRUJ. This sonographic method was used to quantify the pre- and postoperative instability in correlation with clinical outcome in patients with complete TFC disruption. Methods 11 patients with complete disruption of the TFC resulting in symptomatic instability of the DRUJ underwent open reconstruction of the TFC. The instability was measured with sonography preoperatively and one year postoperatively including the Patient-Rated Wrist Evaluation score (PRWE Score). Results By subjective measurement, 9 patients showed comparable stability to the contralateral side. By objective measurements, DRUJ stability was completely restored in 6 patients. Seven patients had a very good and good clinical outcome. The dorsovolar shift (preoperative mean 5.2mm, min 2.4, max 7.1; postoperative 3.6mm, min 1.2, max 6.2) was significantly decreased (p < 0.05) and was postoperatively not different to the contralateral healthy side (p > 0.1). PRWE score in the 1 year follow up was 13.8. Three patients remained with significant pain, sonographically two of them were still more lax and one tighter compared to the contralateral side. Conclusions The sonographic measurement technique allows evaluation of the stability pre- and postoperatively and does not always correlate with the qualitative clinical assessment. The described operation technique is effective for treatment of irreplaceable TFC ruptures and significantly improves the DRUJ stability and wrist function one year after surgery, which could be quantified objectively by ultrasound.

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.

Instability of the distal radioulnar joint

The distal radioulnar joint is a complex structure necessary for forearm motion and force transmission across the wrist. Anatomic and biomechanical advances have revealed broad contributions to distal radioulnar joint stability and refined our understanding of the forces acting across it. Instability often co-occurs with other modes of pathology, such as arthrosis or malunion; and appropriate diagnosis and treatment require a comprehensive understanding of all contributing factors. Distal radioulnar joint instability can be broadly categorized as primary, post-traumatic or post-surgical. Treatment strategies include percutaneous, arthroscopic, soft-tissue, osteotomy and arthroplasty techniques. The purpose of this article is to review distal radioulnar joint instability and its management.

Clinical and ultrasonographic evidence of a proximal positional fault of the radius. A case report

Positional faults are considered a possible underlying mechanism mimicking the symptoms of a joint sprain. Despite numerous clinical studies indicating the presence of positional faults, there is limited evidence of imaging studies confirming positional faults. This case report is a preliminary study that offers clinical and ultrasonographic evidence of a proximal positional fault of the radius, treated successfully with manual therapy techniques. Three weeks after a bike fall on the outstretched hand, the patient in this study presented with right wrist pain and a lack of progress with conventional conservative treatment (NSAIDs, rest and immobilization). Clinical findings indicating a proximal positional fault of the radius included pain during active pronation increased by associating a passive movement of the radius in a proximal direction and it was reduced by associating a passive movement of the radius in a distal direction. Ultrasonographic (US) images showed a reduction of radio-capitellar distance on the right side (11.4 mm) compared to the left side (13.3 mm). A positive response with a distal mobilization of the radius supported the proximal positional fault of the radius. After two manual therapy sessions, the patient had recovered normal asymptomatic function. The outcomes used to assess function and pain were active pronation range of motion, the Spanish version of the DASH questionnaire and a 0-10 numeric pain rating scale. Each measure was conducted prior and after each treatment session and one week post treatment. The patient was re-examined at 6 months follow-up, during which US images, demonstrated a normalization of the right radio-capitellar distance.

In-vivo measurement of distal radio-ulnar joint translation

Distal radio-ulnar joint (DRUJ) instability is increasingly recognised and assessment can be subjective and difficult. Previous research has used cadaveric models or in-vivo with CT, with variable results. A test device was designed to establish normal values of in-vivo DRUJ dorso-palmar translation. Twenty volunteers were recruited. Those with previous wrist/forearm injuries were excluded. The device held the elbow at 90° flexion and neutral forearm rotation, with the distal ulna secured. A dorso-palmar shear force was applied to the distal radius and displacement measured three times on each wrist alternately by the same operator. The mean translation of the DRUJ is 5.5 mm. Same-sided mean measurements for two subjects taken days apart varied by 1 mm. The intra-class correlation coefficient was 0.93. The device is reliable, reproducible and appears to be a simple valid test. Contralateral sides were comparable. It will primarily be a research device to guide clinical practice in DRUJ instability.

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.

[Surgical treatment of Galeazzi fractures in adults by compression plate: about 28 cases]

La fracture de Galeazzi associe une fracture diaphysaire du radius ou des deux os de l'avant bras à une luxation de l'articulation radio ulnaire distale. Décrite en 1934, sa fréquence varie chez l'adulte entre 2,7% et 6,8% de l'ensemble des fractures de l'avant bras. Le traitement admis de façon consensuel chez l'adulte est chirurgical reposant sur une ostéosynthèse stable par une plaque vissée de compression dynamique associée ou non à un embrochage de la radio ulnaire distale. Nous rapportons dans notre étude les résultats cliniques de 28 patients colligés au service de traumatologie et orthopédie A du CHU Hassan II de Fès sur une période de 06 ans. L’âge moyen de nos patients était de 30 ans avec prédominance masculine de 90%; tous nos patients ont présenté un traumatisme de poignet lors d'un accident de sport. Le côté droit était atteint dans 75% des cas. Le bilan radiologique objectiva une fracture diaphysaire du raduis associée à une luxation radio ulnaire distale; nous avons adopté la classification de de Mansat. Le traitement a consisté en une synthèse par une plaque vissée dynamique associée à un embrochage transversal chez six patients qui ont présenté une instabilité de la radio ulnaire distale. L'immobilisation par attelle plâtrée postérieure BABP était de mise. Après un recul de 36 mois, nos résultats ont été très satisfaisants suivant le score de Mestdagh, avec bonne récupération de la mobilité du poignet et reprise de toute activité sportive.

[SPECT/CT in diagnostics of the hand joint]

CLINICAL/METHODICAL ISSUE

Hand and wrist pain remains a diagnostic challenge, both for hand surgeons and for radiologists. Especially chronic wrist pain is often hard to localize clinically and further cross-sectional imaging is often indispensable.

STANDARD RADIOLOGICAL METHODS

The well-established standard for non-invasive diagnostic imaging in chronic wrist pain is magnetic resonance imaging (MRI).

METHODICAL INNOVATIONS

Recently, state-of-the-art single photon emission computed tomography/computed tomography (SPECT/CT) systems have been introduced into the diagnostic array for musculoskeletal conditions. Besides morphological data SPECT/CT also provides metabolic information.

PERFORMANCE

SPECT/CT allows an exact detection and precise anatomical mapping of different pathologies of the wrist, which is often crucial for therapy.

ACHIEVEMENTS

In patients with chronic wrist pain, SPECT/CT is more specific than MRI. It is also beneficial in patients with posttraumatic conditions and metal implants and may serve as a problem-solving tool in difficult cases.

PRACTICAL RECOMMENDATIONS

It is considered that SPECT/CT imaging is useful if MRI results are equivocal or present no clearly leading pathology. A primary examination with SPECT/CT seems to be a reasonable option for patients with certain bone pathologies, metal implants and non-specific wrist pain.

A novel technique for detecting instability of the distal radioulnar joint in complete triangular fibrocartilage complex lesions

We performed this study to investigate whether discrepancy of bilateral dorsovolar shift of the distal radioulnar joint (DRUJ) is decisive for the diagnosis of DRUJ instability. Although several cadaver studies have quantified the amount of physiological dorsovolar shift, so far, there is no reliable method of quantification of DRUJ mobility in daily practice. The aim was to describe a novel sonographic method of quantifying DRUJ instability and evaluate its reliability and validity. In this study, 40 healthy volunteers and 17 patients with complete rupture of the triangular fibrocartilage complex (TFCC) underwent sonographic quantification of the grade of instability of their DRUJ bilaterally. Dorsovolar ulnar head translation relative to the distal radius was quantified by means of ultrasonography performed in a transversal plane through the ulnar head and Lister tubercle. Measurements were done while actively pressing the volar surface of the hand onto a brick 30 degrees pronated, and after lifting the hand. A quotient Q of the radioulnar distance (distance between the dorsal radius surface and the ulnar head) between the unloaded and loaded wrist was calculated for differentiation of a normal and unstable DRUJ. The Q ratio of the 17 patients with unilateral TFCC lesion was significantly different between the pathologic side and the contralateral wrist (1.19 vs. 0.54, p < 0.001). There was no significant difference in the Q ratio in the 40 healthy volunteers between the right and left side or dominant and nondominant wrist. A Q ratio > 0.8 was found to be a reasonable cut-off for pathologic laxity of the DRUJ with a sensitivity of 88% and a specificity of 81%. A quotient Q > 0.8 determines instability of the DRUJ reliably. This was a level II diagnostic study.