Negative Ulnar Variance Lessens DRUJ Instability After DRUJ Disruption: A Biomechanical Analysis

BACKGROUND

The purpose of this study was to perform a biomechanical investigation on the effect of ulnar variance (UV) on the stability of the distal radioulnar joint (DRUJ) prior to and after DRUJ sectioning.

METHODS

Ten cadaveric forearm specimens were included in the study and baseline UV was assessed radiographically. Radial motion relative to the ulna was evaluated using Intel real sense cameras and a custom developed program. The forearms were dissected, and a radial osteotomy was performed. Using a custom-made plate, radial stability was assessed with an UV of + 4, 0, and -4 mm by measuring the maximum and minimum radial position relative to the ulna during a simulated Shuck test. The volar radioulnar ligaments and triangular fibrocartilage complex (TFCC) were then sectioned, and testing was repeated at each UV state.

RESULTS

Sectioning significantly increased radial translation at neutral (P = .008), +4 mm UV (P = .008), and -4 mm UV (P = .018). There were no significant differences in translation between the 3 UV groups with the DRUJ intact (P = .124). The ulnar negative (-4 mm) state had significantly lower translation compared to the positive (+4 mm) (P < .001) and the neutral (0 mm) (P = .026) UV states. There were no significant differences between the positive and neutral UV groups with the DRUJ sectioned.

CONCLUSIONS

Fixating the radius in -4 mm of ulnar negativity significantly decreased radial translation after sectioning the volar radioulnar ligament and TFCC. Ulnar variance had no effect on stability with an intact DRUJ.

STUDY TYPE

Biomechanical Study.

Distal radioulnar joint translation evaluated by maximum intensity projection images of computed tomography

This study compared distal radioulnar joint (DRUJ) translation measured using the subluxation ratio (SR) method between maximum intensity projection (MIP) and conventional CT images on 30 wrists with ulnar positive variance. The results show that DRUJ translation can be reliably evaluated with MIP.

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.

Low-Intensity Pulsed Ultrasound for Delayed Union of Distal Radius Fracture After Palmar Locking Plate Fixation: A Case Report

Delayed union and non-union of distal radial fractures (DRFs) are rare, and there are a few reports of delayed union and nonunion of DRFs after palmar locking plate (PLP) fixation. A 68-year-old female patient presented to our hospital with left-sided wrist pain. Radiographs and computed tomography revealed a displaced DRF and ulnar styloid fracture. We performed open reduction and internal fixation with a PLP for the DRF and tension band wiring for the ulnar styloid fracture. However, bone union was not completed three months after the operation. We initiated low-intensity pulsed ultrasound (LIPUS) to achieve fracture healing. Complete bone union was confirmed radiographically five months after LIPUS. There have been few case reports on the delayed union or nonunion of DRFs after PLP fixation treated with LIPUS. LIPUS might be an effective option for the delayed union of DRFs after PLP fixation.

Association of ulnar variance with three-dimensional carpal alignment and demographics in asymptomatic volunteers

BACKGROUND

Several carpal pathologies are considered to be related to ulnar variance. Recently, computer-aided computed tomography (CT) analysis software was introduced to quantify three-dimensional (3D) carpal alignment with high accuracy and reliability.

PURPOSE

To determine the association of ulnar variance with 3D carpal alignment and demographics.

MATERIAL AND METHODS

A wrist of 121 asymptomatic volunteers (69 men, 52 women; mean age = 38 ± 10.4 years) was imaged in the neutral wrist position with cone-beam CT. Computer-aided CT analysis software (Bonelogic), based on segmentation and numerical modelling, was used to define ulnar variance and standardized 3D axes for all carpal bones. The association of ulnar variance with 3D carpal alignment, age of the volunteer, and side and dominance of the imaged wrist was assessed.

RESULTS

The mean ulnar variance was -1.6 ± 1.5 mm (range = -5.3 to 2.4 mm). The mean ulnar variance was -1.9 mm and -1.1 mm in men and women (P = 0.007), respectively. Of the imaged 121 wrists, 18 (15%) had positive and 103 (85%) negative ulnar variance. There was no association between ulnar variance and any of the radio- or intercarpal angle values in either the sagittal or coronal plane (ρ = -0.16…0.17, r = -0.13….0.12). The ulnar variance showed no association with side (P = 0.51) or dominance (P = 0.27) of the imaged wrist.

CONCLUSION

3D carpal alignment is not affected by ulnar variance. The association of ulnar variance with sex may in part explain the difference in reported prevalence of some carpal pathologies, such as ulnar impaction syndrome and Kienböck's disease.

Ulnar-Sided Sclerosis of the Lunate Does Not Affect Outcomes in Patients Undergoing Volar Locking Plate Fixation for Distal Radius Fracture

BACKGROUND AND AIM

Radial shortening after distal radius fracture causes ulnar impaction, and a mild reduction loss of radial height occurs even after volar locking plate fixation. This study aimed to determine whether preoperative ulnar-sided sclerosis affects clinical outcomes after volar locking plate fixation for distal radius fracture (DRF).

METHOD

Among 369 patients who underwent volar locking plate fixation for DRF, 18 with preoperative ulnar-sided sclerosis of the lunate were included in Group A and compared to a 1:4 age-, sex- and fracture-pattern-matched cohort without sclerosis (72 patients, Group B). The visual analog scale (VAS), Disabilities of the Arm, Shoulder, and Hand (DASH) score, and grip strength were assessed as clinical outcomes. Ulnar variance (UV), radial inclination, radial length, and volar tilt at two weeks after surgery and the final follow-up were measured as radiographic outcomes.

RESULTS

The mean VAS and DASH scores and grip strength did not differ between the two groups. The mean UV at two weeks after surgery and the last follow-up was significantly higher in Group A. The mean changes in UV were +0.62 mm in Group A and +0.48 mm in Group B. There were no significant intergroup differences. Neither UV nor its changes showed any association with DASH and VAS scores.

CONCLUSIONS

Preoperative ulnar-sided sclerosis of the lunate did not affect clinical outcomes after volar locking plate fixation, even if UV increased postoperatively.

Ulnar Variance in Athletes: A Scoping Review

CONTEXT

Ulnar variance (UV) is a measurement of the relative locations of the radius and ulna that may become perturbed in athletic populations. Positive UV can be associated with wrist pathologies often treated conservatively or surgically and may result in interruption of sports participation.

OBJECTIVE

This scoping review aims to summarize diagnostic measures of UV in athletes, describe its relation to separate wrist conditions, and present treatment strategies for symptomatic UV.

DATA SOURCES

A systematic search was created and modified for PubMed, CINAHL, Embase, and SPORTDiscus including articles from inception until February 2, 2022.

STUDY SELECTION

Articles including UV characterization, imaging modality style, and an athletic population were searched across multiple databases.

STUDY DESIGN

A scoping review was designed to identify the methods for imaging UV in athletic populations following the PRISMA Extension for Scoping Reviews (PRISMA-ScR).

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

The specific athletic population, imaging modality, measurement style, wrist pathology association, and surgical management of UV were extracted.

RESULTS

A total of 4321 records were screened independently for eligibility: 22 met inclusion criteria. Eight sports comprised the analysis. All studies referenced conventional radiography to diagnose UV; 50% specified the posteroanterior, 18.2% anteroposterior, and 13.6% pronated, gripping radiographs. Hafner's method (7×), Palmer's technique (2×), and the method of perpendiculars (3×) were used to measure UV. Athletes displayed more positive UV than nonathletes and UV became more positive over time in longitudinal studies. Triangular fibrocartilage complex tears, focal lunate necrosis, and ulnar abutment were associated with positive UV. Ulnar shortening osteotomy was the most performed operation for positive UV.

CONCLUSION

Conventional radiography is the gold standard for imaging UV in athletes. Hafner's method is the most commonly used radiograph measurement technique. Wrist pathology in athletic populations may indicate positive UV in need for operative management.

Accuracy of radiographic measurements of fracture-induced deformity in the distal radius

Background

Management of the distal radius fracture (DRF) is to some extent based on radiographic characterization of fracture displacement. It remains unclear, however, if the measurements used to quantify displacement are accurate.

Purpose

To quantify accuracy of two radiographic measurements: dorsal/volar tilt and fracture compression, measured indirectly as ulnar variance (UV), using radiostereometric analyses (RSA) as reference standard.

Material and Methods

Twenty-one fresh frozen non-fractured human cadaveric forearms (right = 11, left = 10) were thawed and eligible for inclusion. The forearms were mounted on a custom made platform that allowed for controlled forearm rotation, and they underwent two rounds of imaging (both rounds consisted of RSA and radiographs). In round one, the non-fractured forearms were radiographed. In round two, artificial DRF´s with compression and dorsal angulation were created and imaging procedures repeated. Change in tilt and UV between the non-fractured and later fractured forearms was defined as fracture-induced deformity. Deformity was measured radiographically and additionally calculated using RSA. Bland Altman analyses were used to estimate agreement between radiographically measured, and RSA calculated, fracture-induced deformity.

Results

Our results indicated that radiographs underestimate the amount of fracture-induced deformity. Mean measured differences (bias) in dorsal tilt deformity between radiographs and RSA were -2.5° for both observers. The corresponding values for UV were -1.4 mm and -1.5 mm.

Conclusion

Quantifying fracture-induced deformity on radiographs underestimated the actual deformity when compared to RSA calculated deformity. These findings suggest that clinicians, at least in part, base fracture management and potentially corrective surgery on inaccurate measurements.

The effect of ulnar variance on the pisotriquetral joint

BACKGROUND

Pisotriquetral joint (PTJ) disorders are an important cause of ulnar-sided wrist pain but are often underrecognized. Ulnar variance (UV) has been associated with several wrist pathologies.

PURPOSE

To determine the effect of UV on PTJ in patients with trauma.

MATERIAL AND METHODS

A total of 143 patients (77 men, 66 women; mean age=41.64 ± 18.07 years) were included. Patients with fractures, severe and high-energy trauma, arthritic conditions, avascular necrosis, congenital deformity, bone and soft-tissue tumors, suboptimal image quality, and incorrect joint position were excluded. UV and the amount of PTJ subluxation were evaluated using coronal and sagittal computed tomography images.

RESULTS

PTJ subluxation was divided into five grades. A statistically significant difference was found between the presence of PTJ subluxation and sex (P = 0.045). PTJ subluxation was more common in men (46.8%) than in women (30.3%). There was no significant difference between the presence of PTJ subluxation and age (P = 0.758). The patients were also divided into three groups as positive, neutral, and negative UV. A statistically significant relationship was found between the UV and presence of PTJ subluxation (P = 0.01). PTJ subluxation was significantly less in the neutral (none=51.1%, present=48.9%; P < 0.05) and negative (none=77.8%, present=22.2%; P < 0.05) groups.

CONCLUSION

PTJ subluxation was found to be less among the groups with neutral and negative UV in our study population. PTJ subluxation is more common in men while there is no relationship with age. UV and gender may be risk factors for PTJ subluxation by affecting force dynamics at the wrist joint.

Ulnar variance in distal radial fractures: assessment and interpretation

We explored patterns of shortening of the distal radius and investigated the effect of displacement on 'ulnar variance' in 250 patients with distal radial fractures. A small number of patients (5%) had a fracture that resulted in true shortening. Thirty-two per cent had fractures that appeared short, but lateral radiographs revealed that the articular surface was tilted, with either the anterior or dorsal rim of the articular surface being proximal to the distal ulna but the other rim was distal to it. We recommend initial assessment of variance on lateral radiographs. If the anterior and dorsal rims of the distal radial articular surface are proximal to the distal ulna, then true shortening is present and lengthening and stabilization, to hold the radius distracted, should be considered. If only one rim is proximal to the distal ulna, then correction of the tilt will lessen the apparent positive variance.Level of evidence: IV.

The association of three anatomical factors with ulnar-sided wrist pain: a radiological study

BACKGROUND

Ulnar-sided wrist pain is associated with the development of multiple wrist pathologies. But the anatomical etiologies have not been fully understood.

PURPOSE

To determine the association of three anatomical factors with ulnar-sided wrist pain, including ulnar variance (UV), distal ulnar volar angle (DUVA), and pisiform-ulnar distance (PUD).

MATERIAL AND METHODS

A total of 64 patients who had ulnar-sided wrist pain associated with training injuries were retrospectively studied. A control group included 64 healthy athletes from the same unit. The UV, DUVA, and PUD of each individual was measured on radiographs.

RESULTS

The average UV and DUVA of those in the ulnar-sided pain group were 0.84 mm and 174.65°, respectively; the control group values were 0.39 mm and 175.11°. The differences between the two groups had no statistical significance (P > 0.05). The average PUD of the ulnar-sided wrist pain group was shorter than that of the control group (2.37 cm vs. 2.65 cm); the difference had statistical significance (P < 0.05). PUD had a negative correlation with ulnar-sided pain; it was an anatomical protective factor (odds ratio = 0.01; P < 0.00; 95% confidence interval=0.00-0.05). Both UV and DUVA had no significant correlations with ulnar-sided wrist pain (P > 0.05).

CONCLUSION

PUD has a significant correlation with ulnar-sided wrist pain. It is the anatomical protective factor. Both the UV and DUVA have no statistical association with ulnar-sided wrist pain, but we cannot ignore their potential pathogenic effects on wrists, and further studies are needed to confirm the results.

Comparison of extra-articular radiographic parameters of distal radius fractures on plain radiographs and CT scans

The aim of this study was to compare extra-articular radiographic parameters of distal radial fractures measured on plain radiographs and CT scans. Two researchers independently measured four extra-articular radiographic parameters (dorsal tilt, carpal alignment, radial inclination and ulnar variance) on both radiographs and CT scans in 85 patients. Inter-observer reliability for both techniques was assessed, along with the agreement between CT scans and radiographs using the intraclass correlation coefficient and Bland-Altman plots. The results showed that dorsal tilt, carpal alignment, radial inclination and ulnar variance can be measured reliably on both radiographs and CT scans. At a patient level, carpal alignment, radial inclination and ulnar variance CT scan measurements are an acceptable alternative to plain radiograph measurements in the vast majority of patients. In contrast, dorsal tilt CT scan measurements are not comparable with radiographs in 40% of the cases. Therefore, caution should be taken in measuring dorsal tilt on CT scans.

Arthroscopic Anatomy of the TFCC with Relevance to Function and Pathology

Introduction  The authors present a new comprehensive arthroscopic anatomical description of the fibrocartilage complex "TFCC" which is related to the current TFCC functional and pathological knowledge. Methods  Our description of the TFCC is based on an arthroscopic view from the 3-4 portal as observed in more than 100 wrist arthroscopies in fresh cadavers and more than 1000 diagnostic and/or therapeutic wrist arthroscopies. Results  TFCC is considered as a 3-D-3-part box-like structure (Reins, Wall and Disc). The first TFCC component ("R") corresponds to 2 strong radio-ulnar ligamentous Reins, one dorsal (DRUL) and one palmar (PRUL). This "V-shaped" RUL reins diverge from the fovea and ulnar styloid to the volar and dorsal edges of the sigmoid notch. It is a main stabilizer of the DRUJ. The second TFCC component ("W") is a continuous, radially concave Peripheral Capsular Wall attached and perpendicular to the RUL reins. It surrounds the ulnar aspect of the ulno-carpal interval while attaching to the RUL reins proximally and to the medial carpus distally. Along with the radiocarpal ligaments, the TFCC peripheral capsular wall contributes to the stability of the carpus with respect to the radius-ulna entity. This is especially true for the thick volar TFCC capsular wall. The third TFCC component ("D") is the disc proper which is a static and dynamic shock absorber intercalated between the ulnar head and the medial proximal row in the coronal/sagittal planes and between the two strands of the RUL in the axial plane. Its pathology is influenced and related to the ulnar variance. Discussion  This new arthroscopic description of the TFCC provides a comprehensive anatomical, functional ant pathological background for TFCC disorders analysis and treatment. Currently known disorders are included as "R 1,2,3,4", "W 1, 2, 3, 4", and "D 1, 2". Combined TFCC disorders and further new pathology descriptions may be included in this open classification.

Kienböck Disease in a 66-Year-Old Man after Distal Ulna Fracture

Kienböck disease after fracture-dislocations around the wrist is a rare occurrence. This case report presents a case of a 66-year-old man who developed Kienböck disease 18 months after his distal ulnar fracture. The patient developed negative ulnar variance after union of the distal ulnar fracture. Nonsurgical treatment was not effective in relieving his pain. Radial shortening osteotomy was performed based on the negative ulnar variance that developed. One year postoperatively, visual analog scale improved to 0, grip strength improved to 25 kg, and flexion-extension arc improved to 150 degrees. The patient achieved satisfactory clinical outcomes. This is a therapeutic level IV study.

Biomechanics of the Distal Radioulnar Joint During In Vivo Forearm Pronosupination

Background  Ulnar variance (UV) and center of rotation (COR) location at the level of the distal radioulnar joint (DRUJ) change with forearm rotation. Nevertheless, these parameters have not been assessed dynamically during active in vivo pronosupination. This assessment could help us to improve our diagnosis and treatment strategies. Questions/purposes  We sought to (1) mathematically model the UV change, and (2) determine the dynamic COR's location during active pronosupination. Methods  We used biplanar videoradiography to study DRUJ during in vivo pronation and supination in nine healthy subjects. UV was defined as the proximal-distal distance of ulnar fovea with respect to the radial sigmoid notch, and COR was calculated using helical axis of motion parameters. The continuous change of UV was evaluated using a generalized linear regression model. Results  A second-degree polynomial with R 2 of 0.85 was able to model the UV changes. Maximum negative UV occurred at 38.0 degrees supination and maximum positive UV occurred at maximum pronation. At maximum pronation, the COR was located 0.5 ± 1.8 mm ulnarly and 0.6 ± 0.8 mm volarly from the center of the ulnar fovea, while at maximum supination, the COR was located 0.2 ± 0.6 mm radially and 2.0 ± 0.5 mm volarly. Conclusion  Changes in UV and volar translation of the COR are nonlinear at the DRUJ during pronosupination. Clinical Relevance  Understanding the dynamic nature of UV as a function of pronosupination can help guide accurate evaluation and treatment of wrist pathology where the UV is an important consideration. The dynamic behavior of COR might be useful in designing DRUJ replacement implants to match the anatomical motion.

Radial shortening, bone grafting and vascular pedicle implantation versus radial shortening alone in Kienböck's disease

We prospectively compared outcomes of two surgical procedures for Stage II and IIIa Kienböck's disease with negative ulnar variance. Group I (13 wrists) was treated with radial shortening alone, and Group II (14 wrists) with combined radial shortening, bone grafting and implantation of a vascular pedicle. At follow-up 3 to 7 years (mean 4.5) after operation, scores by the Quick version of the Disability of Arm, Shoulder and Hand questionnaire and scores for pain and grip strength were significantly better in Group II, but the differences were rather small. On MRI all patients in Group II had revascularization, but 11 patients in Group I had not. We conclude that combining radial shortening with the revascularization procedure improved revascularization. Clinically, both treatments were efficient, and the additional bone grafting and vascular pedicle insertion did not greatly improve function, although statistically there were differences in several follow-up variables. This study also could not identify the independent role of the three procedures (drilling, grafting and artery insertion) in Group II, because decompression or bone grafting alone may be effective.Level of evidence: II.

Morphology at the Distal Radioulnar Joint: Identifying the Prevalence of Reverse Obliquity

Background  Recent advances in the understanding of ulnar-sided wrist pathologies such as ulnar abutment syndrome (UAS) have brought increased attention to the anatomy of the distal radioulnar joint (DRUJ). Previous work established three anatomical variants of the sigmoid notch (parallel, oblique, and reverse oblique). The reverse oblique DRUJ poses theoretical risk of increased contact forces following ulnar shortening osteotomy, a common method of treating UAS. Purpose  As prevalence of reverse oblique morphology has been under-reported, this study aims to better define the prevalence of reverse oblique morphology in the adult population. Methods  Institutional Review Board-approved review of 1,000 radiographs over a 2-year period was performed. Demographic data and radiographic measurements were recorded (ulnar variance, notch inclination, and presence of arthritis). Correlation tests, a test of proportions, a t -test, and linear and logic regression tests were used to examine associations between ulnar variance, sigmoid inclination, sex, age, and presence of arthritis. Results  One thousand radiographs were analyzed revealing prevalence rates of: parallel-68%, oblique-26%, and reverse oblique-6%. Females were significantly more likely to have reverse inclination. No significant correlation was noted for morphology by age. Ulna positive variance was negatively correlated with reverse inclination. DRUJ arthritis was noted in 14% of patients. Higher sigmoid inclination was associated with higher odds of presence of arthritis, adjusting for sex and age. Higher incidence of arthritis was noted among patients with the oblique (20.8%) or reverse oblique (24.6%) compared with parallel (10.5%) morphology. Conclusion  This series of 1,000 radiographs demonstrates a 6% overall prevalence of reverse obliquity. This large dataset allows for better quantification of the prevalence of DRUJ morphologies and determination of correlations that have clinical implications for patients with ulnar-sided wrist pathology. Level of Evidence  This is a Level IV study.

Midcarpal Structure Effect on Force Distribution through the Radiocarpal Joint

Background  Wrist structure is complicated by distinct anatomical patterns. Previous studies defined radiographic wrist types based on lunate and capitate shape within the midcarpal joint. We hypothesized that these disparate structural patterns will transfer forces differently through the wrist. Objective  This study aims to correlate force transferred to the distal radius and ulna with morphological measurements in cadaver arms. Methods  Radiographs from 46 wrists, previously tested for force transfer between the radius and ulna, were examined. The percentage of compressive force through the distal ulna was determined by mounting load cells to the radius and ulna, while 22.2 Newton (N) tensile forces were individually applied to multiple tendons. Each wrist was tested in a neutral flexion-extension and radial-ulnar deviation position. Results  Wrist type and lunate type were associated with percentage of force transfer through the ulna ( p  = 0.002, p  = 0.0003, respectively). Percentage of force transfer was correlated with capitate circumference ( p  = 0.02, r  = 0.34). Conclusions  This study supports distinct force transfer between morphological wrist types. Clinical Relevance  Understanding the mechanical significance of different structural variations in the wrist bones will improve our ability to understand wrist function and the distinctive development of wrist pathology. Level of Evidence  This is a Level II study.

Ulnolunate Distance and Lunate Height: Reliability Testing

PURPOSE

Many methods for measuring ulnar variance have been described. The purpose of this study was to introduce the use of both lunate height and ulnolunate distance on the zero-rotation view as well as to assess the intra- and interobserver reliabilities of these measurements. The hypothesis was that the use of concave surfaces in the measurement of both lunate height and ulnolunate distance will yield a higher intra- and interobserver reliability than ulnar variance, which uses the convex surface of the distal radius.

METHODS

Seven hand fellows reviewed 32 radiographs. Measurements of lunate height, ulnolunate distance, and ulnar variance, using the method of perpendiculars, were recorded to the nearest 0.5 mm. Intraclass correlation coefficient (ICC) was then calculated for each radiograph for intra- and interobserver reliability.

RESULTS

The ICC measurements were similar for lunate height, ulnolunate distance, and ulnar variance. The inter- and intraobserver reliability was similar for all 3 measurements.

CONCLUSIONS

Measurements of ulnar variance utilize the concave surface of the distal radius. The use of the convex surface of the lunate and pole of the ulna does not seem to improve the reliability of these measurements. Further studies are necessary to confirm the clinical utility of these measurements.

CLINICAL RELEVANCE

The use of ulnolunate distance and lunate height as an adjunct to ulnar variance may assist in evaluation of distal radius fractures and ulnocarpal abutment, improve surgeon communication, and contribute to our overall knowledge of the wrist.

Clinical and Radiographic Correlates for the Treatment of Ulnocarpal Impaction

Background  Ulnocarpal impaction (UCI) is a described cause of ulnar side wrist pain. Questions  Does absolute ulnar variance (UV) or change in UV with grip affect patient-rated outcome scores (PROS) in patients with symptomatic UCI undergoing surgery? Does UV differ between symptomatic and contralateral wrists? Does arthroscopic grade of triangular fibrocartilaginous complex (TFCC) tears and lunotriquetral (LT) ligament tears influence PROS? Do PROS improve following ulnar shortening osteotomy (USO) or wafer procedures and does improvement depend on the amount of shortening or achievement of negative UV? Patients and Methods  We analyzed information on patients undergoing USO or wafer procedures for UCI as recorded in a database of prospectively collected information on individuals with ulnar side wrist pain. This included (1) patient-rated wrist evaluation and QuickDASH scores on enrolment, 3 and 12 months postoperatively; (2) standardized bilateral posteroanterior (PA) wrist radiographs, including PA grip views of the symptomatic wrist; and (3) arthroscopic findings. Results  Larger changes in UV between PA neutral and grip views prior to surgery were associated with smaller improvements in PROS, 12 months after surgery. Actual UV value before and after surgery did not affect PROS. There was no difference in UV between symptomatic and contralateral wrists. The presence of TFCC or LT ligament tears did not influence PROS. Mean PROS improved postoperatively. Conclusions  Ulnar shortening procedures result in improvement in PROS in patients with UCI. Variation in UV with rotation and grip results in variable outcomes. Level of Evidence  This is a Level II, cohort study.

During forearm rotation the three-dimensional ulnolunate distance is affected more by translation of the ulnar head than change in ulnar variance

Ulnolunate abutment has been thought to be aggravated by pronation because of an increase in ulnar variance. We hypothesized that the ulnolunate distance might be greater in pronation because the ulnar head is dorsally translated. Twenty-one three-dimensional reconstructions of computed tomographic scans of wrists taken in supination and pronation were investigated. The ulnolunate distance was measured in each position, and the change in ulnolunate distance from supination to pronation was calculated. The changes in ulnar variance from supination to pronation and the amount of translation of the ulnar head were measured directly by superimposing three-dimensional reconstructions. The mean ulnolunate distance in pronation was significantly greater than in supination. There was no significant correlation between the changes in ulnolunate distance and in the ulnar variance. The change in ulnolunate distance had a significant positive linear relationship with the amount of translation of the ulnar head. The change in ulnolunate distance during forearm rotation is determined by the amount of translation of the ulnar head rather than by change in ulnar variance. Level of evidence: IV.

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.

Distal radius nonunion after volar locking plate fixation of a distal radius fracture: a case report

We describe a 59-year-old man who had nonunion of a right distal radius fracture after volar locking plate fixation. He underwent open reduction and internal fixation with a volar locking plate system for a dorsally displaced, unstable distal radius fracture at a previous hospital 5 months ago. Radiographs of the injured wrist showed nonunion of the distal radius with 1.5-mm ulnar minus variance. Radiographs of the unaffected wrist showed 3.5-mm ulnar plus variance. Intraoperative findings of surgical revision showed an unstable nonunion; thus, debridement of the nonunion, autogenous inlay bone grafting, and internal fixation using another type of volar locking plate system were performed. Healing of the re-operative site was confirmed radiographically 3 months postoperatively. We considered that volar locking plate fixation with excessive distraction of the fracture may lead to nonunion.

Correlation of the Lateral Wrist Radiograph to Ulnar Variance: A Cadaveric Study

PURPOSE

Both positive and negative ulnar variance have been implicated in a variety of wrist disorders. Surgery aims to correct the variance in these pathologic conditions. This necessitates accurate and reproducible measuring tools; however, the most accurate radiographic measurement technique remains unclear. The purposes of this study were to evaluate 3 methods for determining ulnar variance and to compare each with direct anatomic measurement in a cadaver model.

METHODS

We fixed 10 fresh above-elbow cadaver specimens in neutral rotation and obtained standardized fluoroscopic posteroanterior and lateral wrist images. A dorsal approach was performed and two independent investigators directly measured ulnar variance using digital calipers with the cartilage both intact and denuded. Ulnar variance was measured radiographically using the lateral, perpendicular, and central reference point methods. The reliability of each set of measurements (within a 1-mm cutoff) was assessed by the intraclass coefficient; agreement between radiographic and direct measurements was evaluated by the Bland-Altman method.

RESULTS

Each method of determining ulnar variance demonstrated near perfect agreement by the intraclass coefficient. The lateral radiograph method correlated highly with the directly measured ulnar variance with the cartilage denuded with an average measurement difference of 0.06 mm. No radiographic measurement technique demonstrated consistent agreement within 1 mm of the measured ulnar variance with the cartilage intact.

CONCLUSIONS

Ulnar variance measured by the lateral wrist radiograph technique correlates highly with the directly measured osseous ulnar variance. The remaining measurement techniques did not correlate reliably to within 1 mm of the directly measured ulnar variance with 95% confidence. No method was able to account accurately for the articular cartilage thicknesses at the lunate facet of the radius or the distal ulnar head, which we found to vary in an unpredictable manner. Whereas the lateral radiograph has been shown to allow for more reliable standardization of wrist position compared with the posteroanterior view, this study also highlights the inherent limitations of using static radiographic images in evaluating ulnar variance.

CLINICAL RELEVANCE

The results of the current study demonstrate the utility of the lateral wrist radiograph for assessing bony ulnar variance.

The Parallelogram Effect: The Association Between Central Band and Positive Ulnar Variance

PURPOSE

Ulnar impaction syndrome is a poorly understood degenerative wrist condition characterized by symptoms of pain thought to be caused by increased loads between the ulnar head and the carpals. Radiographic evaluation often reveals an ulnar-positive wrist. We hypothesize that progressive elongation of the central band of the forearm interosseous ligaments changes the longitudinal radial-ulnar relationships, resulting in an ulnar-positive wrist. The objective of the study was to identify a relationship between the loss of integrity of the forearm interosseous ligaments and increased ulnar variance.

METHODS

Six cadaveric human forearms were used to measure displacement of the radius relative to the ulna during axial loading of the lunate fossa of the radius. Radial heights were measured in supination and pronation under a 5-lbF (22-N) preload. Gradual axial loads were applied up to 50 lbF (222N); the resultant axial displacement was measured in supination and pronation. All measurements were evaluated with the interosseous ligament intact and repeated with the central band cut.

RESULTS

With an applied 5-lbF preload, cutting the central band increased ulnar variance by 3.02 ± 0.80 mm in supination and by 2.15 ± 0.79 mm in pronation. In supination, when the loads were increased from the 5-lbF preload to 50 lbF, the radius displaced 2.1 times further after the central band was cut (3.00 mm) compared with the group with the intact forearm construct (1.41 mm). In pronation, when the loads were increased from the 5-lbF preload to 50 lbF, the radius displaced 1.8 times further when the central band was cut (2.84 mm) than with the intact forearm construct (1.57 mm).

CONCLUSIONS

Because of a parallelogram effect, the radius shifted proximally under a 5-lbF preload, creating an ulnar-positive wrist relationship. Dynamic loading of the forearm after ligament excision resulted in significant additional radial displacement relative to the intact forearm.

CLINICAL RELEVANCE

Deficiency in the ligamentous restraints of the central band leads to positive ulnar variance, which could be a factor (among others) that contributes to idiopathic ulnar impaction syndrome.

Vascularized Bone Graft to the Lunate Combined With Temporary Scaphocapitate Fixation for Treatment of Stage III Kienböck Disease: A Report of the Results, a Minimum of 2 Years After Surgery

PURPOSE

To report the outcomes of patients with stage III Kienböck disease treated by vascularized bone graft (VBG) followed by temporary scaphocapitate (SC) fixation, a minimum of 2 years after surgery.

METHODS

Twenty-six patients (mean age, 35 years) with stage III Kienböck disease (16 with stage IIIA and 10 with stage IIIB), treated with VBG followed by SC fixation for 4 months, were retrospectively followed for at least 2 years (range, 24-121 months; mean, 61.8 months). The preoperative and postoperative assessments included range of motion (ROM) of the wrist, grip strength (GS), wrist pain, the modified Mayo wrist score (MMWS), carpal height ratio (CHR), Ståhl index (STI), and radioscaphoid angle (RSA). The outcomes of each assessment of the stages IIIA and IIIB groups at the final examination were compared with those before surgery.

RESULTS

In both stages IIIA and IIIB groups, GS increased after surgery. Decrease of CHR and STI was associated with the increase of RSA in the stage IIIA group after surgery, while RSA decreased, although neither CHR nor STI significantly increased in the stage IIIB patients. No patient demonstrated deterioration of the wrist pain after surgery. Twenty-one of 26 patients had an improved MMWS grade at the final follow-up.

CONCLUSIONS

Vascularized bone graft combined with SC fixation for 4 months provided greater GS, pain relief, and functional improvement compared with before surgery in both stages IIIA and IIIB groups.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

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.

Risk Factors of Lunate Collapse in Kienböck Disease

PURPOSE

Not all patients with Kienböck disease progress to collapse of the lunate and carpal malalignment, but it is difficult to determine which patients are at risk. We aimed to identify demographic or anatomical factors associated with more advanced stages of Kienböck disease.

METHODS

We included all 195 eligible patients with Kienböck disease and available preoperative posteroanterior and lateral radiographs. We compared the mean age, sex distribution, mean ulnar variance, radial height, radial (ulnarward) inclination, palmar tilt, anteroposterior distance, and lunate type among the different Lichtman stages of Kienböck disease and performed ordinal logistic regression analysis.

RESULTS

We found that patients with more negative ulnar variance had more advanced stages of Kienböck disease (adjusted odds ratio, 1.4). An increase in age was also independently associated with a higher Lichtman stage of Kienböck disease (adjusted odds ratio, 1.02).

CONCLUSIONS

Our findings suggest that more negative ulnar variance may be related to a greater magnitude of lunate collapse in Kienböck disease. Additional long-term study is needed to confirm the longitudinal relationship of negative ulnar variance with progressive Kienböck disease.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Interobserver Agreement in Diagnosing Early-Stage Kienböck Disease on Radiographs and Magnetic Resonance Imaging

BACKGROUND

The appearance of early Kienböck disease on radiographs and magnetic resonance imaging (MRI) may be difficult to distinguish from other conditions that affect the lunate. We aimed to assess the interobserver agreement in the diagnosis of early Kienböck disease when evaluated on different imaging modalities.

METHODS

Forty-three hand surgeon members of the Science of Variation Group were randomized to evaluate radiographs and 35 hand surgeons to evaluate radiographs and MRI scans of 26 patients for the presence of Kienböck disease, the lunate type, and the ulnar variance. We used Fleiss' kappa analysis to assess the interobserver agreement for categorical variables and compared the κ values between the 2 groups.

RESULTS

We found that agreement on the diagnosis of early Kienböck disease was fair (κ, 0.36) among observers who evaluated radiographs alone and moderate (κ, 0.58) among observers who evaluated MRI scans in addition to radiographs, and that the difference in κ values was not statistically significant ( P = .057). Agreement did not differ between observers based on imaging modality with regard to the assessment of the lunate type ( P = .75) and ulnar variance ( P = .15).

CONCLUSIONS

We found, with the numbers evaluated, a notable but nonsignificant difference in agreement in favor of observers who evaluated MRI scans in addition to radiographs compared with radiographs alone. Surgeons should be aware that the diagnosis of Kienböck disease in the precollapse stages is not well defined, as evidenced by the substantial interobserver variability.

Negative Ulnar Variance and Kienböck Disease

PURPOSE

To test the primary null hypothesis that there is no difference in mean ulnar variance (UV) scaled to the length of the capitates between 166 wrists with Kienböck disease and an equal number of matched controls and to test the secondary null hypothesis that mean scaled UV does not vary based on age, sex, or race in both Kienböck and control wrists.

METHODS

Ulnar variance was measured on posteroanterior radiographs of the wrist as the distance between a line through the midpoint between the volar and the dorsal edges of the ulnar margin of the radius and a line tangential to the most distal aspect of the carpal surface of the head of the ulna, both perpendicular to the longitudinal axis of the radius. Measurement of UV was scaled to the length of the capitate, resulting in a UV to capitate height (UV:CH) ratio.

RESULTS

We found a significant difference in mean UV:CH ratio between patients with Kienböck disease and a control group matched by age, sex, race, and limb. The prevalence of negative UV was high in both patients with Kienböck disease and matched controls. There were no differences in mean UV:CH ratio with respect to age, sex, or race among patients with Kienböck disease or matched controls.

CONCLUSIONS

The precise role of ulna minus in the development of Kienböck disease remains uncertain and unanswered, given that many patients with Kienböck disease have neutral or positive UV. In addition, a large proportion of the normal population has negative UV, whereas Kienböck disease is rare.

Ulnar Shortening Osteotomy After Distal Radius Fracture Malunion: Review of Literature

Malunion of distal radius fracture is often complicated with shortening of the radius with disturbed radio- ulnar variance, frequently associated with lesions of triangular fibrocartilage complex and instability of the distal radioulnar joint. Positive ulnar variance may result in wrist pain located in ulnar part of the joint, limited ulnar deviation and forearm rotation with development of degenerative changes due to the overloading that occurs between the ulnar head and corresponding carpus. Ulnar shortening osteotomy (USO) is the standard procedure for correcting positive ulnar variance. Goal of this procedure is to minimize the symptoms by restoring the neutral radio - ulnar variance. In this paper we present a variety of surgical techniques available for ulnar shorthening osteotomy, their advantages and drawbacks. Methods of ulnar shortening osteotomies are divided into intraarticular and extraarticular. Intraarticular method of ulnar shortening can be performed arthroscopically or through open approach. Extraarticular methods include subcapital osteotomy and osteotomy of ulnar diaphysis, which depending on shape can be transverse, oblique, and step cut. All of those osteotomies can be performed along wrist arthroscopy in order to dispose and treat possibly existing triangular fibrocartilage complex injuries. At the end we described surgical procedures that can be done in case of ulnar shorthening osteotomy failure.

Force variations in the distal radius and ulna: effect of ulnar variance and forearm motion

PURPOSE

To better define normal wrist joint forces during wrist motion and forearm motion at specific wrist and forearm positions and to see if there is a relationship between these forces and the amount of ulnar variance. A secondary purpose was to determine the relationship between the thickness of the articular disk of the triangular fibrocartilage complex and the amount of force transmitted through the distal ulna.

METHODS

Multi-axis load cells were attached to the distal radius and ulna of 9 fresh cadaver forearms. The axial radial and ulnar compressive forces were recorded while each wrist was moved through wrist and forearm motions using a modified wrist joint simulator. During each motion, the tendon forces required to cause each motion were recorded. The ulnar variance and triangular fibrocartilage complex articular disc thickness were measured.

RESULTS

The axial force through the distal ulna and the wrist extensor forces were greatest with the forearm in pronation. No relationship was found between the amount of force through the distal ulna and the amount of ulnar variance. A strong inverse relationship was found between the triangular fibrocartilage complex thickness and the ulnar variance.

CONCLUSIONS

Wrists with positive ulnar variance have generally been thought to transmit greater loads across the distal ulna, which has been felt to predispose these wrists to the development of ulnar impaction. The results of this study appear to show that all wrists have similar loading across the distal ulna regardless of ulnar variance. By comparison, pronation relatively increases loading across the distal ulna.

CLINICAL RELEVANCE

Because these results suggest that within reasonable ranges of ulnar variance loading across the distal ulna is independent of ulnar variance, the clinically observed incidence of ulnar impaction is more likely the result of increased wear on a thinner and less durable triangular fibrocartilage complex than due to increased distal ulna loading in ulnar positive variant wrists.

Inter- and intrarater reliability of ulna variance versus lunate subsidence measurements in Madelung deformity

PURPOSE

To assess inter- and intrarater reliability of both ulna variance and lunate subsidence measurement methods in a large consecutive series of children with Madelung deformity.

METHODS

Ulnar variance and lunate subsidence were measured on 41 standard anteroposterior wrist radiographs from 31 patients with Madelung deformity. The patients had a mean age of 13 years (range, 5-25) at the time of presentation. Two pediatric orthopedic hand/upper limb surgeons evaluated all radiographs twice in a 4-week interval using standard digital imaging software. Intraclass correlation coefficients (ICCs) were calculated for inter- and intrarater reliability, and results were reported using the Landis and Koch criteria.

RESULTS

The interrater ICC for the ulna variance measurements was substantial, and for the lunate subsidence almost perfect. The intrarater ICC for ulna variance was substantial for both raters. In contrast, the intrarater ICC for lunate subsidence was almost perfect for both raters.

CONCLUSIONS

Measurement of lunate subsidence showed both superior interrater and intrarater reliability compared with the ulnar variance method. Whenever relative ulna length is assessed in children and adolescents with Madelung deformity, the lunate subsidence should be the preferred method to characterize deformity.

A comparison of 3-D computed tomography versus 2-D radiography measurements of ulnar variance and ulnolunate distance during forearm rotation

Positive ulnar variance is associated with ulnar impaction syndrome and ulnar variance is reported to increase with pronation. However, radiographic measurement can be affected markedly by the incident angle of the X-ray beam. We performed three-dimensional (3-D) computed tomography measurements of ulnar variance and ulnolunate distance during forearm rotation and compared these with plain radiographic measurements in 15 healthy wrists. From supination to pronation, ulnar variance increased in all cases on the radiographs; mean ulnar variance increased significantly and mean ulnolunate distance decreased significantly. However on 3-D imaging, ulna variance decreased in 12 cases on moving into pronation and increased in three cases; neither the mean ulnar variance nor mean ulnolunate distance changed significantly. Our results suggest that the forearm position in which ulnar variance increased varies among individuals. This may explain why some patients with ulnar impaction syndrome complain of wrist pain exacerbated by forearm supination. It also suggests that standard radiographic assessments of ulnar variance are unreliable.

Proximal radial diaphyseal segment resection for posttraumatic proximal radioulnar synostosis: a prospective study of 15 cases

BACKGROUND

Proximal radioulnar synostosis is a complication after elbow injuries. Various treatment methods have been reported and are associated with unpredictable outcomes. In a prospective study, we evaluated the medium-term effects of proximal radial resection on wrist and elbow function and forearm rotation in 15 cases.

METHODS

We treated 15 patients with posttraumatic proximal radioulnar synostosis by resection of 1 cm of the proximal radial diaphysis. On the preoperative examination and last follow-up, the Mayo Elbow Performance Score, grip force, visual analog scale for elbow and wrist score, radiographic ulnar variance changes, and elbow range of motion were measured. The Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score and the general satisfaction of the patients were assessed at the final follow-up.

RESULTS

The mean duration of follow-up was 31 ± 13 months. The mean active postoperative supination/pronation arc was 101° ± 45°. The mean increase measured in the ulnar variance at the final follow-up was 3.3 ± 1.5 mm (P = .02). The mean final QuickDASH score was 13.3 ± 12.1. The preoperative and final Mayo scores were 57 ± 10 and 91 ± 7, respectively (P = .01). The general satisfaction with the results of the operation was 86.6%.

CONCLUSIONS

We suggest that proximal radial resection for the treatment of posttraumatic proximal radioulnar synostosis shows acceptable results in adults regarding the recovery of range of motion and patient satisfaction. This technique might be considered as a salvage procedure, particularly in cases with previous failed heterotopic resection at the proximal radioulnar joint, resulting in disturbed anatomy.

LEVEL OF EVIDENCE

Level IV, case series, treatment study.

Reconstructed animation from four-phase grip MRI of the wrist with ulnar-sided pain

In order to visualize dynamic variations related to ulnar-sided wrist pain, animation was reconstructed from T2* coronal-sectioned magnetic resonance imaging in each of the four phases of grip motion for nine wrists in patients with ulnar pain. Eight of the nine wrists showed a positive ulnar variance of less than 2 mm. Ulnocarpal impaction and triangular fibrocartilage complex injury were assessed on the basis of animation and arthroscopy, respectively. Animation revealed ulnocarpal impaction in four wrists. In one of the four wrists, the torn portion of the articular disc was impinged between the ulnar head and ulnar proximal side of the lunate. In another wrist, the ulnar head impacted the lunate directly through the defect in the articular disc that had previously been excised. An ulnar shortening osteotomy successfully relieved ulnar wrist pain in all four cases with both ulnocarpal impaction and Palmer's Class II triangular fibrocartilage complex tears. This method demonstrated impairment of the articular disc and longitudinal instability of the distal radioulnar joint simultaneously and should be of value in investigating dynamic pathophysiology causing ulnar wrist pain.

The association of Kienbock's disease and ulnar variance in the Iranian population

We retrospectively determined the distribution of ulnar variance in 60 patients with Kienböck's disease. We also measured the ulnar variances in 400 standard wrist radiographs in the normal adult population. The mean ulnar variance of the Kienböck's group was -1.1 mm (SD 1.7) and the mean ulnar variance of the general population was +0.7 (SD 1.5), which was significantly different. In the Kienböck's disease group there were 38 (63%) with ulnar negative, 16 (27%) neutral and six (10%) with ulnar positive variance. The preponderance of ulnar negative variance was statistically significant. There was an association between ulnar negative variance and the development of Kienböck's disease in this study.