Ulnar-positive variance as a predictor of distal radioulnar joint ligament disruption

Ulnar-Sided Wrist Pain: A Diagnostic Evaluation Guide From 30-Plus Years of Experience

INTRODUCTION

While multiple ulnar-sided wrist pain (USWP) diagnostic evaluation guides have been presented, none have included original clinical data or statistical analysis. The purpose of this study is to provide a diagnostic evaluation guide derived from original clinical data and analysis to help clinicians arrive at a differential diagnosis for USWP.

METHODS

Using a computer search of patients presenting with sprains, instability, and laxity of the wrist, 385 patient charts were identified. Patient demographics, mechanism of injury, subjective complaints, physical findings, and diagnostic test findings were reviewed. Statistical analysis was performed to determine sensitivity and specificity of diagnostic methods on their ability to identify lunotriquetral ligament tears, triangular fibrocartilage complex (TFCC) tears, and ulnar impaction syndrome. Diagnostic arthroscopy was used as the reference standard.

RESULTS

Ninety-three patients, comprising 101 cases of USWP, were included in the study. The onset of injury was traumatic in 83 out of 101 cases with motor vehicle accidents (N=46) being the most common, followed by overuse (N=18), and a fall onto an outstretched hand (N=16). The ulnocarpal tenderness test exhibited sensitivity/specificity of 72%/33%; lunotriquetral ligament laxity test of 42%/62%; bone scan of 80%/33%; radiocarpal arthrogram of 90%/98% for TFCC tears and 50%/91% for lunotriquetral ligament tears; midcarpal arthrogram of 82%/86% for lunotriquetral ligament tears. The mean ulnar variance on standard posteroanterior view radiograph was 0.95 mm, increasing to 2.67 mm on gripping posteroanterior view.

CONCLUSION

Physicians should suspect a lunotriquetral ligament and/or TFCC tear with the acute onset of USWP following a loaded dorsiflexed mechanism of injury. Ulnocarpal tenderness tests and pre-operative ulnar variance measures are effective for increasing suspicion of USW pathology. Bone scans are helpful in diagnosing ulnar impaction syndrome in conjunction with radiographic findings. A combination of midcarpal arthrogram for lunotriquetral ligament tears and radiocarpal arthrogram for TFCC tears should be employed.

Altered Ulnar Variance With Full-Body Weight-bearing During Handstands With Upper Extremity Weight-bearing CT

PURPOSE

Ulnar variance (UV) is a radiographic measurement relating the articular surface heights of the distal radius and ulna. Abnormal UV increases the risk for wrist pathology; however, it only provides a static measurement of an inherently dynamic bony relationship that changes with wrist position and loading. The purpose of this study was to investigate how full-body weight-bearing affects UV using weight-bearing computed tomography (WBCT).

METHODS

Ten gymnasts completed two 45-second scans inside a WBCT machine while performing a handstand on a flat platform (H) and parallettes (P). A non-weight-bearing CT scan was collected to match clinical practice (N). Differences in UV between weight-bearing conditions were evaluated separately for dominant and nondominant sides, and then, UV was compared between weight-bearing conditions on pooled dominant/nondominant data.

RESULTS

Pooled analyses comparing weight-bearing conditions revealed a significant increase in UV for H versus N (0.58 mm) and P versus N (1.00 mm), but no significant change in UV for H versus P (0.43 mm). Significant differences in UV were detected for H versus N, P versus N, and H versus P for dominant and nondominant extremities. The change from N to H was significantly greater in the dominant versus nondominant side, but greater in the nondominant side from N to P.

CONCLUSIONS

Ulnar variance changed with the application of load and position of the wrist. Differences in UV were found between dominant and nondominant extremities.

CLINICAL RELEVANCE

Upper extremity loading patterns are affected by hand dominance as defined by a cartwheel and suggest skeletal consequences from repetitive load on a dominantly used wrist. Although statistically significant, subtle changes detected in this investigational study do not necessarily bear clinical significance. Future WBCT research can lead to improved diagnostic measures for wrist pathologies affected by active loading and rotational wrist behavior.

Ulnar positive variance associated with TFCC foveal tear

OBJECTIVE

The ulnar positive variance (UPV) can be observed on simple radiography due to a triangular fibrocartilage complex (TFCC) foveal tear. This study investigated to identify how much radiographic UPV occurs due to a TFCC foveal tear, which may be misdiagnosed as an ulnar impaction syndrome (UIS).

MATERIALS AND METHODS

One hundred forty patients who underwent arthroscopic transosseus TFCC foveal repair from March 2013 to March 2019 in our institution were enrolled in this study. Ulnar variances were measured in preoperative, postoperative 6 weeks, 1-year follow-up wrist posteroanterior (PA) radiograph, and power grip PA radiograph of the affected wrist and were compared with those of the same patient's unaffected wrist.

RESULTS

In the neutral wrist PA radiograph, ulnar variance increased by 0.56 mm (p < 0.001) after TFCC foveal tear compared to the unaffected side. In the power grip view, ulnar variance also increased by 0.39 mm (p < 0.001) in the affected wrist. The preoperative ulnar positive variance was reduced after an arthroscopic transosseous TFCC foveal repair from 0.56 to 0 mm (p < 0.001). No significant statistical difference was observed between an Atzei class 2 and 3 TFCC tear (0.56 mm vs. 0.41 mm, p = 0.263).

CONCLUSION

This study revealed that TFCC foveal tear induces 0.56 mm of radiologic UPV, which was successfully corrected after arthroscopic transosseous TFCC foveal repair. Therefore, UPV associated with TFCC foveal tear should not be misdiagnosed as an UIS. Also, when ulnar shortening osteotomy is planned in case of UIS combined with TFCC foveal tear, the amount of UPV induced by TFCC foveal tear should be considered to prevent over-shortening.

The Value Added of Advanced Imaging in the Diagnosis and Treatment of Triangular Fibrocartilage Complex Pathology

PURPOSE

Pathology of the triangular fibrocartilage complex is a prevalent cause of ulnar-sided wrist pain that presents a diagnostic challenge. We hypothesized that a history and physical examination (H&P) would be more cost-effective alone or with diagnostic injection than with magnetic resonance imaging (MRI) or magnetic resonance arthrogram (MRA) in the diagnosis and treatment of a symptomatic triangular fibrocartilage complex abnormality.

METHODS

A simple-chain decision analysis model was constructed to assess simulated subjects with ulnar-sided wrist pain and normal radiographs using several diagnostic algorithms: H&P alone, H&P + injection, H&P with delayed advanced imaging (MRI or MRA), and H&P + injection with delayed advanced imaging (MRI or MRA). Three years after diagnosis, effectiveness was calculated in Disabilities of the Arm, Shoulder, and Hand-adjusted life years. Costs were extracted from a commercial insurance database using US dollars. A probabilistic sensitivity analysis with 10,000 second-order trials with sampling of parameter distributions was performed. One-way and 2-way sensitivity analyses were performed.

RESULTS

All strategies had similar mean effectiveness between 2.228 and 2.232 Disabilities of the Arm, Shoulder, and Hand-adjusted life years, with mean costs ranging from $5,584 (H&P alone) to $5,980 (H&P, injection, and MRA). History and physical examination alone or with injection were the most cost-effective strategies. History and physical examination alone was the most preferred diagnostic strategy, though H&P + injection and H&P with delayed MRA were preferred with adjustments in willingness-to-pay and parameter inputs. As willingness-to-pay increased considerably (>$65,000 per Disabilities of the Arm, Shoulder, and Hand-adjusted life year), inclusion of MRA became the most favorable strategy.

CONCLUSIONS

Advanced imaging adds costs and provides minimal increases in effectiveness in the diagnosis and treatment of a symptomatic triangular fibrocartilage complex abnormality. The most cost-effective strategy is H&P, with or without diagnostic injection. Magnetic resonance arthrogram may be favored in situations with a high willingness-to-pay or poor examination characteristics.

TYPE OF STUDY/LEVEL OF EVIDENCE

Economic/Decision Analysis IV.

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.

The Combined Procedure of Ulnar Metaphyseal Shortening Osteotomy With Triangular Fibrocartilage Complex Foveal Knotless Repair

Ulnar impaction syndrome (UIS) and triangular fibrocartilage complex (TFCC) tear are common causes of ulnar-sided wrist pain. As a standard surgical treatment, ulnar-shortening osteotomy (USO) and TFCC repair are used respectively. Patient spectrums of UIS accompanied by distal radioulnar joint instability or traumatic TFCC foveal tear with UIS symptoms exist, and both USO and TFCC repair are necessary for treating some of these patients. However, there have been few reports on the procedure for performing these 2 operations concurrently. We introduce a combined procedure to concurrently perform USO and TFCC repair. We performed a USO in the ulnar metaphysis using a locking plate and open TFCC knotless repair using a suture anchor at the ulnar fovea. In this technique, USO is conducted in the metaphysis, which is favorable to union, using a small plate that is easy to handle, and knotless TFCC repair can be performed simultaneously through a single small incision.

In Vivo Mechanical Function of the Distal Radial Ulnar Ligaments During Rotation of the Wrist

PURPOSE

The purpose of this study was to investigate changes in length of the volar and dorsal radioulnar ligaments (VRULs and DRULs), and the distal radioulnar joint (DRUJ) space during unweighted and weighted rotation of the wrist using magnetic resonance imaging and biplanar fluoroscopy.

METHODS

Fourteen wrists in 7 normal adult volunteers were imaged to define the 3-dimensional geometry of the DRUJ and the insertion sites of the superficial and deep bundles of the VRULs and DRULs. Subjects were imaged at 10 positions of forearm rotation ranging from full pronation to full supination, with or without a 5-pound weight. Lengths of the superficial and deep VRUL and DRUL bundles and DRUJ space were measured (in millimeters) at each position to evaluate ligament function and DRUJ stability.

RESULTS

In the unweighted and weighted trials, maximal elongation of both deep and superficial VRUL bundles occurred in supination and maximal lengths of the deep and superficial DRUL bundles occurred in pronation. Maximum DRUJ space occurred during pronation and a minimum occurred in 30° of supination. In weighted trials, there was a significant increase in deep and superficial VRUL bundle length at positions between 30° of pronation and 30° of supination; however, there was no effect of weight on DRULs length. In weighted trials, there was a significant increase in DRUJ space at positions between full pronation and 15° of supination.

CONCLUSIONS

This study demonstrates elongation of the VRULs in supination and the DRULs in pronation. There was no evidence of reciprocal loading of superficial/deep ligament bundles on either the dorsal or the volar aspects of the DRUJ. The effect of loading the wrist during rotation was apparent primarily in the VRULs, but not the DRULs. The DRUJ space was lowest at approximately 30° of supination.

CLINICAL RELEVANCE

These results add information to the literature regarding the complicated biomechanics of the triangular fibrocartilage complex and DRUJ. Future work should evaluate changes in biomechanics caused by triangular fibrocartilage complex tears to determine how tear severity and location relate to clinical symptoms.

[Arthroscopy of the distal radioulnar joint]

OBJECTIVE

The aim of the procedure is to visualize the proximal pouch of the DRUJ, the joint surfaces of the sigmoid notch and the ulnar head, the convexity of the ulnar head and the proximal ulnar side surface of the triangular fibrocartilage complex (TFCC).

INDICATIONS

Arthroscopy of the distal radioulnar joint is applied for the evaluation of joint pathologies in ulnar-sided wrist pain, especially in cases without diagnostic findings in standard X‑rays and MRIs and arthroscopically assisted procedures.

SURGICAL TECHNIQUE

In vertical extension, two portals of the wrist are created on the dorsal side of the DRUJ between the extensor digiti minimi and extensor carpi ulnaris tendons. By insertion of a small joint arthroscope via these portals visualization of the ulnar head, the sigmoid notch, the proximal pouch of the DRUJ and the proximal surface of the TFCC is accomplished.

CONCLUSIONS

Arthroscopy of the DRUJ is a rarely and not routinely performed procedure for the diagnosis and therapy of ulnar-sided wrist pain. It is technical demanding with a flat learning curve and anatomy-related obstacles. A complete view of the joint is not always accessible. Rare complications are injuries of the extensor digiti minimi tendon, as well as contusion or sectioning of the transverse branch of the dorsal branch of the ulnar nerve. In distinct cases, this procedure offers important additional information about the distal radioulnar joint. The procedure is especially valuable for the detection of proximal TFCC injuries that are missed otherwise.

Changes in Ulnar Variance after a Triangular Fibrocartilage Complex Tear

Purpose  The relationship between triangular fibrocartilage complex (TFCC) tear and ulnar impaction syndrome has not been fully understood. We hypothesized that a TFCC tear could change the ulnar variance, which may be the cause of ulnar impaction syndrome. Patients and Methods  A total of 72 patients who underwent TFCC foveal repair between January 2011 and June 2016 were included in this retrospective study. Among them, 44 patients diagnosed with TFCC foveal tear with distal radioulnar joint instability and no ulnar impaction syndrome underwent TFCC foveal repair only (group A) and 28 patients diagnosed with TFCC foveal tear with ulnar impaction syndrome underwent TFCC foveal repair and ulnar shortening osteotomy simultaneously (group B). We measured their ulnar variances in preoperative, postoperative, and last follow-up plain radiography. We also compared them with the ulnar variance of the contralateral (uninjured) wrist. Postoperative clinical outcomes, such as range of motions of the wrist, the visual analog scale (VAS) for pain, grip strength, and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, were assessed. Results  Ulnar variance increased after TFCC tears compared with that on the uninjured side in both groups (group A: 0.98 vs. 0.52 mm, p  = 0.013; group B: 2.71 vs. 2.13 mm, p  = 0.001). Once the TFCC was repaired, ulnar variance decreased (group A: 0.98 to 0.01 mm, p  < 0.01; group B: 2.71 to 0.64 mm, p  < 0.01). However, it was increased on the last follow-up radiograph (group A: 0.01 to 0.81 mm, p  < 0.01; group B: 0.64 to 1.05 mm, p  = 0.004). There were no significant improvement of range of motion, except for pronation-supination motion ( p  = 0.04). Mean grip strength increased from 56.8 to 70.8% of the contralateral unaffected hand at the last assessment ( p  = 0.01). Mean VAS for pain decreased from 7.4 ± 2.5 preoperatively to 2.7 ± 2 postoperatively ( p  = 0.001). The QuickDASH score significantly improved from 45 to 9 ( p  = 0.001). Conclusion  Ulnar variance may be changed after a TFCC tear. In our study, it decreased after TFCC foveal repair. However, as time went on, the ulnar variance increased again, which could be one of the causes of ulnar impaction syndrome and ulnar-sided wrist pain. Level of Evidence  This is a therapeutic Level IV study.

The Role of Triangular Fibrocartilage Complex in Axial Stability of the Forearm

Background  The triangular fibrocartilage complex (TFCC) provides stability to the wrist and disruption of this complex can result in axial instability which can lead to ulnocarpal abutment. Purpose  This article determines the individual contributions of the volar radioulnar ligament (VRUL), dorsal radioulnar ligament (DRUL), and foveal attachment of the TFCC to longitudinal stability of the forearm under axial load. Materials and Methods  Eighteen cadaveric specimens were randomly assigned into three groups representing the component of the TFCC to be initially transected: VRUL, DRUL, and foveal attachment. Prior to transection, posterioranterior radiographs of the wrist were obtained at 0, 44.5, and 90 N of axial load. Serial transection of the TFCC components were performed with radiographs obtained at each of the aforementioned loads. Ulnar variance was assessed with two-way repeated measures analysis of variance and paired t -tests. Results  Transection of the foveal attachment demonstrated a significant change in ulnar variance of 1.5 and 0.6 mm under 45 and 90 N of load, respectively. At 0 N of load, there was no significant change in ulnar variance between an intact wrist and a wrist with all three ligaments transected; however, a significant change in ulnar variance, 1.0 mm, was observed under 90 N of load. Conclusion  The foveal attachment of the TFCC provides the largest contribution to axial stability. Clinical Relevance  The TFCC provides axial stability to the wrist and disruption of the TFCC may result in change in ulnar variance observed on an axial loaded wrist radiograph.

The Effect of Axial Loading on Ulnar Variance

Background  Forearm rotation results in change in ulnar variance. Axial loading of the wrist is required to maintain daily activities. Change in ulnar variance during axial loading has not been investigated previously. Purpose  To measure the change in ulnar variance on axially loaded wrists. Patients and Methods  We examined 21 asymptomatic individuals and 24 patients with unilateral ulnar-sided wrist pain. All patients underwent standard neutral posteroanterior wrist radiographs without load and under axial loading on bilateral wrists. Axial loading was standardized at 18.1 kgf using an analog weight scale. A magnetic resonance (MR) arthrogram was obtained only in patients with ulnar-sided wrist pain. Beighton flexibility score was recorded on healthy volunteers. Change in ulnar variance between 0 and 18.1 kgf was compared for each wrist among all subjects. A correlation was sought between the change in ulnar variance, MR arthrogram findings, and physical examination. Results  In individuals without wrist pain, on average, 0.4 mm increase in ulnar variance was measured between 0 and 18.1 kgf. There was no difference between the dominant and nondominant side. No correlation was found with increasing age. In contrast, patients with ulnar-sided wrist pain displayed an average increase of 0.8 mm in ulnar variance. Compared with the contralateral wrist, more than 1 mm increase in ulnar variance was correlated with intra-articular pathologies including dorsoulnar ligament disruption, central triangular fibrocartilage complex (TFCC) perforation, and foveal detachment. Conclusion  Compared with contralateral side, more than 1 mm increase in ulnar variance is suggestive of longitudinal instability or TFCC pathology. Level of Evidence  Level II, diagnostic.

Dual Plating Technique for Volar Rim Fracture of the Distal Radius Using DePuy-Synthes 2.0 m and 2.4 mm Locking Plates

BACKGROUND

To assess the surgical results of distal radius fractures with the involvement of a volar rim fragment using the DePuy-Synthes 2.0 mm and 2.4 mm locking plates.

METHODS

Subjects were six women and one man of average age 57 years (range, 31-83 y) and a mean follow-up period of 9 months (range, 5-19 mo) with AO B3 (volar shearing) distal radius fractures. Time of the procedure, physical examination of wrist range of motion, grip strength compared with the contralateral healthy wrist, and radiographic evaluation (volar tilt, radial inclination, and ulnar variance) were evaluated. The Visual Analog Scale (VAS: 0 points represents no pain, 100 points represents the worst pain possible) and the Quick Disability of the Arm, Shoulder, and Hand questionnaire (QuickDASH, 0 = no disability, 100 = extreme disability) were completed by patients at the final follow-up.

RESULTS

The average time of the procedure was 74 min. There were no perioperative complications. Average radiographic measures were: volar tilt, 8°; radial inclination, 23°, and ulnar variance, 0 mm. Wrist range of motion averaged 63° in wrist extension (range, 55-80°) and 55° in wrist flexion (range, 45-65°). Grip strength averaged 81% of the contralateral side at final evaluation (range, 67-100%). The mean QuickDASH score was 3.0 points (range, 0-9.1 points) and the mean VAS for pain was 9.3 at final follow-up.

CONCLUSIONS

Open reduction internal fixation with the DePuy-Synthes 2.0 mm and 2.4 mm locking plates is an effective means of fixing a distal radius fracture that includes a volar rim fragment without interfering with flexor tendon gliding.

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.

Measurement of the Shift in the Distal Radioulnar Joint Using a Custom Platform

Diagnosis of subluxation and dislocation of the distal radioulnar joint (DRUJ) is difficult. In order to measure the shift between radius and ulna, we evaluate a method with a custom platform in this study. Cadaver specimen was fixed on a custom platform, and the volar and dorsal translation of the ulnar head was measured under different stress forces. We built a subluxation model via a surgical procedure that removed components of the radioulnar joint, and the translation at varying stress levels was measured again. We find at the same stress level, the normal model results in significantly less translation than the subluxation model at the majority of the stress forces, and particularly with volar forces. Our results indicate that this measurement is a potential method to evaluate the stability of the DRUJ.

The Outcomes of Arthroscopic Repair Versus Debridement for Chronic Unstable Triangular Fibrocartilage Complex Tears in Patients Undergoing Ulnar-Shortening Osteotomy

PURPOSE

The aim of this study was to compare the results of arthroscopic peripheral repair (AR) and arthroscopic debridement (AD) for the treatment of chronic unstable triangular fibrocartilage complex (TFCC) tears in ulnar-positive patients undergoing ulnar-shortening osteotomy (USO).

METHODS

A total of 31 patients who underwent arthroscopic treatments combined with USO for unstable TFCC tears and were followed-up at a minimum of 24 months were included in this retrospective cohort study. Fifteen patients were treated with AR, and 16 patients were treated with AD while at the same time undergoing a USO. Outcome measures included wrist range of motion, grip strength, Disabilities of the Arm, Shoulder, and Hand (DASH) and Patient-Rated Wrist Evaluation (PRWE) scores, and overall outcomes according to the modified Mayo wrist scoring system. In addition, a stress test to assess distal radioulnar joint (DRUJ) stability was performed before and after surgery to compare the 2 cohorts.

RESULTS

Both respective cohorts showed significant improvements in grip strength and subjective scores at the final follow-up. Grip strength, DASH, and PRWE scores were better in the AR group than in the AD group. The recovery rate from DRUJ instability observed during the preoperative examination was superior in the AR group.

CONCLUSIONS

Both AD and AR of the TFCC combined with USO are reliable procedures with satisfactory clinical outcomes for unstable TFCC tears in ulnar-positive patients. However, AR of the TFCC is suggested if DRUJ stability is concomitantly compromised.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Update TFCC: histology and pathology, classification, examination and diagnostics

The TFCC is a crucial stabilizer of the DRUJ. Based on its superficial and deep fibers, the TFCC guarantees unrestricted pronation and supination which is essential for performing sophisticated tasks. The ability to perform complex movements is of uppermost importance for hand function. Therefore, a functional intact TFCC is a prerequisite in this context. The articular disc of the TFCC is a fibrocartilaginous extension of the superficial zone of hyaline articular cartilage which arises from the radius. The peripheral 10-40 % of the TFC is vascularized. Degeneration of the articular disc is common with increasing age. Even though the central part of the articular disc is avascular, potential regeneration of lesions could be detected. The Palmer and Atzei classifications of TFCC lesions are complementary. TFCC innervation is based on different nerves. There is a high variability. A diligent clinical examination facilitates specific tests which help to allocate symptoms to the pathology. Therefore, a thorough clinical examination is not dispensable. Wrist arthroscopy remains the "gold standard" for diagnosing TFCC pathologies despite technical progress in imaging modalities. MR arthrography may have the potential to become a real alternative to wrist arthroscopy for diagnosing TFCC pathologies with technical progress in the future.

The effect of acute distal radioulnar joint laxity on outcome after volar plate fixation of distal radius fractures

OBJECTIVES

The objective of this study was to determine whether intraoperative laxity of the distal radioulnar joint (DRUJ) is associated with adverse postoperative outcomes after volar plate fixation of a distal radius fracture (DRF) and 4 weeks of immobilization.

DESIGNS

Prospective study with clinical and radiographic assessment.

SETTING

Level 1 trauma center.

PATIENTS

One hundred consecutive patients were treated by volar locking plate fixation at our institution for an unstable DRF from April 2007 to November 2009. Of these patients, 84 patients with a minimum follow-up of 12 months were enrolled in this study.

INTERVENTION

Intraoperative DRUJ laxity was evaluated using a radioulnar stress test after fixation of DRF using volar locking plate and splint immobilization of the forearm for 1 month in patients with intraoperative DRUJ laxity. Patients were allocated to an unstable group or stable group according to the presence of intraoperative DRUJ laxity.

MAIN OUTCOME MEASUREMENTS

Our primary outcome measure was disabilities of arm, shoulder, and hand score and the secondary outcome measures were wrist motion, grip strength, modified Mayo wrist score, visual analogue scale for wrist pain, and ongoing pain in the DRUJ.

RESULTS

Nineteen of the 84 study subjects were allocated to the unstable group and 65 to the stable group. No significant differences were observed between 2 groups in wrist range of motion, grip strength, modified Mayo wrist score, disabilities of arm, shoulder, and hand score, visual analogue scale score, and ongoing pain in the DRUJ at 1 year postoperatively.

CONCLUSIONS

In our series of patients treated with volar locking plate and immobilization of the forearm for 1 month in patients with intraoperative laxity of the DRUJ, laxity did not affect impairment, pain, or disability 1 year after fracture. However, the role of postoperative immobilization of the forearm is debatable and merits additional study.

LEVEL OF EVIDENCE

Prognostic level I.

Clinical and radiographic factors associated with distal radioulnar joint instability in distal radius fractures

BACKGROUND

Distal radioulnar joint (DRUJ) instability is an important cause of ulnar-sided wrist pain in distal radius fractures. However, instability is frequently undiagnosed and the clinical and radiographic factors associated with instability are not well understood.

QUESTIONS/PURPOSES

We therefore identified clinical and radiographic factors associated with DRUJ instability in distal radius fractures.

PATIENTS AND METHODS

We retrospectively reviewed all 221 patients who underwent surgical treatment for unstable distal radius fractures from 2007 to 2010. Ten patients (five men and five women) had DRUJ instability by intraoperative manual testing (Group I); these patients had a median age of 52 years. The other 211 patients (81 men and 130 women) (Group II) had a median age of 55 years. Clinical and radiographic data were compared between the groups.

RESULTS

The incidence of open wounds at the wrist and the relative ulnar length measured on the prereduction radiograph were greater in Group I. An open wound at the wrist and positive ulnar variance of 6 mm or greater on the prereduction radiograph increased the risk of DRUJ instability (relative risks = 45 and 17, respectively) in distal radius fractures.

CONCLUSIONS

An open wound at the wrist or positive ulnar variance of 6 mm or greater observed on the prereduction radiograph in patients with distal radius fractures should alert the physician to the possibility of DRUJ instability.

LEVEL OF EVIDENCE

Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Distal radioulnar joint stress radiography for detecting radioulnar ligament injury

PURPOSE

To determine the reliability and efficacy of clenched-fist stress radiographs in patients with radioulnar ligament injury.

METHODS

We examined 30 patients with chronic radioulnar ligament injury. These patients underwent stress radiography, which included clenched-fist posteroanterior (PA) views in forearm pronation and computed tomography in pronation. We measured distal radioulnar joint (DRUJ) gap distance and ulnar variance using clenched-fist PA views. We measured the radioulnar ratio with pronated computed tomography to quantify dorsal translation of the ulnar head. We analyzed these radiographic data and compared them between the injured and contralateral sides. We examined test-retest reliability and interobserver and intraobserver reliability using intraclass correlation coefficients as a measurement of the DRUJ gap distance in clenched-fist PA views.

RESULTS

The DRUJ gap distance observed with clenched-fist PA views in injured wrists was significantly greater than in the contralateral side. The DRUJ gap distance observed with stress radiography significantly correlated with the magnitude of the radioulnar ratio in forearm pronation. We found a significant test-retest reliability for measuring DRUJ gap distance using clenched-fist PA views, as well as a significant level of intraobserver and interobserver reliability.

CONCLUSIONS

The DRUJ gap distance observed with clenched-fist PA radiography in forearm pronation was a reliable parameter and may be useful for evaluating DRUJ instability.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

ARTHROSCOPIC VISUALISATION OF THE DISTAL RADIOULNAR JOINT

The diagnosis of chronic wrist pain is challenging and wrist arthroscopy has been recognised as the "gold standard". The present study investigated the efficacy of adding distal radioulnar joint (DRUJ) arthroscopy to routine wrist arthroscopy. The records of 67 patients who underwent DRUJ arthroscopy were reviewed, and the success rates for visualisation of intra-articular structures were determined. Pathological findings were correlated with ulnar-side wrist pain. In seven patients, pre-operative diagnoses were altered after DRUJ arthroscopy. The ulnar head and proximal surface of the triangular fibrocartilage complex (TFCC) were visualised in 100% and 99% of patients, respectively, while the foveal insertion of TFCC and sigmoid notch were visualised in 57% and 69%, respectively. Pathological findings of the proximal surface of TFCC tended to relate to ulnar wrist pain (p = 0.06). DRUJ arthroscopy should be included in routine wrist arthroscopy to enhance the accuracy of diagnosis.

Remodeling of distal ulna after excision arthroplasty for acute comminuted distal ulnar fracture: a case report

Bone adaptation after excision arthroplasty of distal radioulnar joint in an acute traumatic distal ulna fracture has never been reported. A case of irreparable and comminuted distal ulnar head fracture was managed by excising the ulna head and repairing the fovea (deep ligament) attachments of distal radioulnar ligaments, and then an unexpected remodeling of the distal ulna with the shape of pole and seat was noted. The anatomy of deep fibers of distal radioulnar ligament is important not only in biomechanics about the stability of distal radioulnar joint but it is also possible in the morphology about the shape of the distal radioulnar joint.

Management of peripheral triangular fibrocartilage complex tears in the ulnar positive patient: arthroscopic repair versus ulnar shortening osteotomy

PURPOSE

One pattern of injury to the triangular fibrocartilage complex (TFCC) is a traumatic peripheral tear located at the ulnar end of the TFCC. Since 1989, this specific injury has been classified as a Palmer type 1B lesion. Various treatment options have been described for 1B injuries, yet when there is coexistent ulnar positive variance, it can make the choice of treatment difficult. The purpose of this article is to help the surgeon decide how to treat type 1B lesions in ulnar positive patients by directly comparing arthroscopic repair (repair) to ulnar shortening osteotomy (USO). The null hypothesis was that repair and USO would provide equivalent postoperative improvement with regard to motion; Disability of the Arm, Shoulder, and Hand (DASH) score; visual analog scale (VAS) score; and grip strength.

METHODS

We tested our hypothesis by retrospectively reviewing prospectively collected data from 51 patients treated surgically between 2000 and 2006 with type 1B tears in the setting of ulnar positive variance. Of these 51 patients, 27 were treated with arthroscopic repair and 24 with USO. All patients were evaluated before surgery as well as at final follow-up for active range of motion measurements, grip strength, DASH score, and VAS score. Radiographs were taken of all patients before surgery to confirm the presence of ulnar positive variance, and after surgery in the USO group to evaluate for bony union.

RESULTS

At the final follow-up, we found no statistically significant difference between the repair and USO groups with regard to flexion, extension, pronation, supination, radial deviation, or ulnar deviation. Likewise, there was no significant difference in grip strength, DASH scores, or VAS scores. When analyzing each cohort individually, both groups improved significantly after surgery with regard to DASH score, VAS score, and wrist extension. There was also a trend toward improved motion in all other directions except for an insignificant decrease in postoperative pronation in the repair group. Two patients in the USO group required additional surgery, with one revision performed for nonunion and one for painful hardware, which caused extensor carpi ulnaris tendonitis.

CONCLUSIONS

The results of our study suggest that type 1B TFCC tears in the ulnar positive patient can be managed equivalently well with repair or USO.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

In-vivo kinematic analysis of forearm rotation using helical axis analysis

BACKGROUND

Controversy still exists regarding the location and nature (static or dynamic) of the forearm joint axis. This might be due to inconsistent results from in-vitro data and less precise methods of analysis. We present the first in-vivo kinematic analysis of normal forearm joint rotation described by helical axis analysis.

METHODS

Data obtained from computed tomography images of both forearms of five healthy volunteers was used to calculate finite helical axis parameters from transformation matrices. Four positions were analyzed: maximum pronation, maximum supination, 60 degrees pronation, and 60 degrees supination. Kinematic analysis focused on the motion of the radius around the ulna.

FINDINGS

The forearm axis as defined by finite helical axis extended from the radial head between its kinematic center and the proximal radioulnar joint, to the dorsal region of the ulnar head at the distal radioulnar joint. The axis was found to be variable.

INTERPRETATIONS

Helical axis analysis has precisely defined the nature and location of the forearm axis. This new information of forearm kinematics defined by finite helical analysis, may be useful in implant design, and in guiding surgeons in their reconstruction of instabilities of the distal and proximal radioulnar joint.

Importance of distal radioulnar joint arthroscopy for evaluating the triangular fibrocartilage complex

BACKGROUND

The present study evaluated the importance of visualizing both sides of the triangular fibrocartilage complex (TFCC) when diagnosing ulnar wrist pain.

METHODS

A total of 20 patients with ulnar wrist pain who underwent both radiocarpal joint (RCJ) and distal radioulnar joint (DRUJ) arthroscopy were studied retrospectively. TFCC was graded as normal or as having wear or tear. The definitive diagnosis was made by evaluating the TFCC from both joints. The medical records were reviewed to document the preoperative diagnosis, arthroscopic findings, postoperative diagnosis, and operative procedure(s) performed after the arthroscopic examinations. The patients' status at final follow-up was evaluated using the modified Green and O'Brien wrist scoring system. The TFCC grading on RCJ and DRUJ arthroscopies was compared.

RESULTS

The final diagnosis was modified after arthroscopic examination in three cases (15%). In six patients (30%), DRUJ arthroscopy revealed pathological TFCC findings that could not be detected on RCJ arthroscopy. The DRUJ arthroscopy detected wear or degenerative changes seen only on the proximal aspect of the TFCC in four patients and tear in two patients. On the other hand, in only one patient (5%) were there no pathological findings observed from the DRUJ portal, although RCJ arthroscopy found wear. In eight patients (45%), the arthroscopic grading of TFCC was the same on RCJ and DRUJ arthroscopy; of these, the TFCC was graded as normal in one patient, showing wear in three patients, and with a tear in five patients. For diagnosing TFCC pathology, RCJ arthroscopy had a sensitivity of 68% and a negative predictive value (NPV) of 14%, whereas the sensitivity was 95% and the NPV was 50% for DRUJ.

CONCLUSIONS

Adding DRUJ arthroscopy to RCJ arthroscopy enables more accurate diagnosis of TFCC pathology because the proximal aspect of the articular disk and the foveal insertion of the distal radioulnar ligament can be visualized.

In vivo three-dimensional displacement of the distal radioulnar joint during resisted forearm rotation

PURPOSE

The in vivo displacement of the distal radioulnar joint (DRUJ) while under resisted pronation or supination has never been previously quantified. Being a joint with 3 dimensions of motion (dorsopalmar translation, changes in ulnar variance, and radioulnar coaptation), our purpose was to determine its 3-dimensional (3D) displacement during resisted rotational torque.

METHODS

Ten normal subjects (aged 31.8 years+/-7.8; F, 5; M, 5) were recruited. Computed tomography scans of a subjects' distal forearms were obtained while grasping the handles of a custom apparatus to keep the fist and forearm in neutral rotation. Scanning was performed in 3 conditions: no rotational torque (control), maximum isometric supination, and maximum isometric pronation. The 3D displacement of the DRUJ, using the ulnar fovea as the reference point, during isometric rotational torque was determined using markerless bone registration techniques.

RESULTS

The mean 3D displacement of the ulnar fovea during maximum isometric pronation and maximum isometric supination was 3.09 mm+/-0.94 and 2.17 mm+/-1.55, respectively. During maximum isometric pronation, the ulnar fovea displaced a mean of 0.51 mm+/-1.79 dorsally. During maximum isometric supination, the ulnar fovea displaced a mean of 0.13 mm+/-2.07 volarly. In both conditions, ulnar variance increased (0.23 mm+/-2.52 for isometric pronation and 0.44 mm+/-1.57 for isometric supination), and there was increased radioulnar coaptation (0.37 mm+/-0.86 for isometric pronation, 0.039 mm+/-0.66 for isometric supination).

CONCLUSIONS

Resisted rotational torque can be applied to the DRUJ while in neutral rotation during computed tomography imaging, producing measurable displacements in 3D. This technique of studying the DRUJ has the potential to improve our ability to detect and quantify instabilities of the DRUJ.