Distal Radioulnar Joint Incongruity After Shortening of the Ulna

Does the distal radioulnar joint orientation influence the outcome of ulnar shortening osteotomy: a retrospective study

The aim of this retrospective study was to evaluate the long-term outcome of ulnar shortening osteotomy. A total of 66 patients treated with an ulnar shortening osteotomy for a primary or post-traumatic ulnar impaction syndrome were included, with a median follow-up time of 75 months.There was a positive correlation between the sigmoid notch angle and the final QuickDASH score, but no correlation with final range of motion, grip strength or pain level. Radiological signs of osteoarthritis of the distal radioulnar joint were seen in 20% of patients, yet there was no correlation between the development of distal radioulnar joint osteoarthritis and the sigmoid notch angle. No symptomatic distal radioulnar joint osteoarthritis was observed.Ulnar shortening osteotomy is a good option to treat patients with ulnar impaction syndrome regardless of the distal radioulnar joint angle.Level of evidence: IV.

Stress distribution pattern in the distal radioulnar joint before and after ulnar shortening osteotomy in patients with ulnar impaction syndrome

Ulnar shortening osteotomy (USO) for ulnar impaction syndrome potentially leads to degenerative changes of the distal radioulnar joint (DRUJ). This study was performed to evaluate the effect of the sigmoid notch morphology on the stress distribution pattern of the DRUJ using computed tomography (CT) osteoabsorptiometry (CT-OAM). We reviewed the pre- and postoperative transverse CT images of 15 wrists that had undergone USO. The examined wrists were classified into two groups based on the sigmoid notch morphology: the linear-type notch (type L) and the curved-type notch (type C). We calculated and statistically compared the percentage of the high-density area (%HDA) in each divided region of the sigmoid notch. In type L, %HDA was significantly larger in the distal-dorsal region of the sigmoid notch before USO. Postoperatively, in type L, no specific regions showed a significantly different %HDA. In type C, %HDA was significantly larger in the distal-volar region of the sigmoid notch before USO. Postoperatively, %HDA of type C was significantly larger in the proximal-volar region. Our results suggest that in patients with ulnar impaction syndrome, morphological evaluation of the sigmoid notch can serve as a predictor of osteoarthritis in the DRUJ with or without USO.

Long-term radiographic outcomes and functional evaluation of ulnar shortening osteotomy in patients with ulnar impaction syndrome and reverse oblique sigmoid notch: a retrospective case series study

BACKGROUND

Ulnar shortening osteotomy (USO) is an effective treatment for ulnar impaction syndrome. However, there have been reports of osteoarthritis (OA) at the distal radioulnar joint (DRUJ) when USO was performed on patients with a reverse oblique sigmoid notch. This study aimed to evaluate the radiographic and functional outcomes following USO in patients with a reverse oblique sigmoid notch.

METHODS

We retrospectively reviewed patients having a reverse oblique sigmoid notch who underwent USO for ulnar impaction syndrome between 2002 and 2013. We evaluated radiographic changes of the DRUJ and functional outcomes of patients.

RESULTS

We enrolled 22 patients (22 wrists) with an average age of 49.6 years and a mean follow-up of 93.2 (range, 36-179; standard deviation [SD], 38.2) months. We found that there were changes in the inclination angle of the sigmoid notch, from an average reverse oblique of 14.9^o (range, 11^o-23^o; SD, 3.4^o) preoperatively to a more parallel 5.1^o (range, 0^o-11^o; SD, 3.2^o) at the final follow-up. The functional results at the final follow-up were good, with a mean visual analogue scale for pain of 0.2 (range, 0-1; SD, 0.4) at rest and 1.3 (range, 0-3; SD, 0.9) during activity, QuickDASH of 15.1 (range, 2.3-34.1; SD, 8.8), and modified Mayo Wrist Score of 91.6 (range, 70-100; SD, 6.4). Seven wrists (31.8%) had changes compatible with OA, but the wrists did not exhibit a significantly worse function when compared to wrists without OA changes, except for supination motion and grip strength.

CONCLUSIONS

For patients with a reverse oblique sigmoid inclination following USO, we observed that the inclination angle had a tendency to become parallel and some patients developed OA at the DRUJ. However, long-term functional outcomes could still be good. The reverse oblique sigmoid inclination does not seem to be an absolute contraindication for USO.

Three-Dimensional Automated Assessment of the Distal Radioulnar Joint Morphology According to Sigmoid Notch Surface Orientation

PURPOSE

To develop reproducible 3-dimensional measurements for quantification of the distal radioulnar joint (DRUJ) morphology. We hypothesized that automated 3-dimensional measurement of the ulnar variance (UV) and the sigmoid notch (SN) angle would be comparable to those of the reference standard while overcoming some drawbacks of conventional 2-dimensional measurements.

METHODS

Radiological data of healthy forearm bones (radiographs and computed tomography) of 53 adult subjects were included in the study. Automated measurements were developed for assessment of the SN morphology based on 3-dimensional landmarks, incorporating subject-specific estimation of cartilage surface orientation. A common anatomical reference was defined among the different imaging modalities and a comparison of the SN angle and UV measurements was performed in radiographs, computed tomography scans, and 3-dimensional models. Finally, the 3-dimensional UV measurements were evaluated in an experimental setup using 3-dimensional printed bone models.

RESULTS

The automated 3-dimensional measurements of SN subtypes showed a notably larger notch radius (18.9 mm) for negative SN angles compared with positive SN angles in subjects (16.9 mm). Similar UV measurements were obtained in healthy DRUJ morphologies, with a high correlation between radiographs and 3-dimensional measurements for the SN angle (0.77) and UV (0.85). In the experimental setup with pathological radial inclinations, UV was on average 1.13 mm larger in the radiographs compared with the 3-dimensional measurements, and 1.30 mm larger in the cases with pathological palmar tilts. Furthermore, UV radiograph measurements on the modified palmar tilt deviated from the 3-dimensional measurements.

CONCLUSIONS

The developed 3-dimensional automated measurements were able to quantify morphological differences among sigmoid notch subtypes and were comparable to those of the reference standard.

CLINICAL RELEVANCE

The developed methods do not depend on the forearm position or orientation of the distal radius and can be used for 3-dimensional quantification of DRUJ pathologies in 3-dimensional surgical planning.

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.

The correlation between shape of the sigmoid notch of the distal radius and the risk of triangular fibrocartilage complex foveal tear

Aims

The aim of this study was to analyze the association between the shape of the distal radius sigmoid notch and triangular fibrocartilage complex (TFCC) foveal tear.

Methods

Between 2013 and 2018, patients were retrospectively recruited in two different groups. The patient group comprised individuals who underwent arthroscopic transosseous TFCC foveal repair for foveal tear of the wrist. The control group comprised individuals presenting with various diseases around wrist not affecting the TFCC. The study recruited 176 patients (58 patients, 118 controls). The sigmoid notch shape was classified into four types (flat-face, C-, S-, and ski-slope types) and three radiological parameters related to the sigmoid notch (namely, the radius curvature, depth, and version angle) were measured. The association of radiological parameters and sigmoid notch types with the TFCC foveal tear was investigated in univariate and multivariate analyses. Receiver operating characteristic curves were used to estimate a cut-off for any statistically significant variables.

Results

Univariate analysis showed that the flat-face type was more prevalent in the patients than in the control group (43% vs 21%; p = 0.002), while the C-type was lower in the patients than in the control group (3% vs 17%; p = 0.011). The depth and version angle of sigmoid notch showed a negative association with the TFCC foveal tear in the multivariate analysis (depth: odds ratio (OR) 0.380; p = 0.037; version angle: OR 0.896; p = 0.033). Estimated cut-off values were 1.34 mm for the depth (area under the curve (AUC) = 0.725) and 10.45° for the version angle (AUC = 0.726).

Conclusion

The proportion of flat-face sigmoid notch type was greater in the patient group than in the control group. The depth and version angle of sigmoid notch were negatively associated with TFCC foveal injury. Cite this article: Bone Joint J 2020;102-B(6):749–754.

Distal radioulnar joint configurations in three-dimensional computed tomography in patients with idiopathic ulnar impaction syndrome

We retrospectively reviewed 26 patients diagnosed with idiopathic ulnar impaction syndrome and measured the slopes of the sigmoid notch and ulnar head at their centre using their preoperative three-dimensional computed tomography. We found that the slope of the sigmoid notch and that of the ulnar head were not parallel to each other. There was a significant linear relation between the slope of the ulnar head and the changes in the closest joint space of the distal radioulnar joint at the centre of the sigmoid notch after ulnar shortening. We conclude that the slope of the ulnar head is more strongly correlated with changes in the closest joint space in the distal radioulnar joint than that of the sigmoid notch. Our findings suggest that slope of the ulnar head might be as important a predisposing factor as that of the sigmoid notch for the progression of distal radioulnar joint arthritis after ulnar-shortening osteotomy. We should consider the slopes of both the sigmoid notch and ulnar head before the osteotomy. Level of evidence: IV.

Morphological characteristics of the sigmoid notch of the distal radius affect the stress distribution patterns in the distal radioulnar joint

The aim of this study was to clarify the effects of morphological patterns of the sigmoid notch on the stress distribution across the articular surface of the distal radioulnar joint using a computed tomography osteoabsorptiometry method. Fourteen wrists from 13 patients were classified into two groups according to the type of sigmoid notch, namely the 'C' type and ski-slope sigmoids, and the percentages of high-density areas on the articular surface were quantitatively analysed. The percentage of the high-density area of the dorsal region in the ski-slope sigmoid group was significantly greater than that of the 'C' type sigmoid group (16% vs 4.1%) and of the volar region of the ski-slope sigmoid group (16% vs 2.4%). The results indicate that bony morphological differences in the radial sigmoid notch affect the stress distribution pattern through the distal radioulnar joint.

Radiological degenerative changes in the distal radioulnar joint after ulnar shortening osteotomy in patients with idiopathic ulnar impaction syndrome: Analysis of factors affecting degenerative lesions

PURPOSE

To identify factors influencing overall radiologic changes in the distal radioulnar joint after ulnar shortening osteotomy (USO) in patients with idiopathic ulnar impaction syndrome.

MATERIALS AND METHODS

A total of 310 patients who had undergone USO between May 2007 and December 2013 were included in this retrospective case-control study. The patients were classified into two groups (with or without radiologic findings of new arthritic changes), after which the following factors were analyzed: 1) demographic factors; 2) radiologic aspects, including ulnar variance (UV), morphological DRUJ type (classified according to Tolat et al.), and union period after USO; and 3) operative aspects, including the triangular fibrocartilage complex degeneration type, use of a parallel double-blade saw, type of plate used for fixation, and plate position on the volar or dorsal ulnar surface.

RESULTS

Group 1 (no arthritic changes) consisted of 243 patients, whereas Group 2 (arthritic changes) consisted of 67 patients. Univariate and multivariate analyses showed that the presence of lunate cystic changes, amount of shortening, and the union period were significantly associated with newly developed arthritic changes in the distal radioulnar joint (DRUJ) after USO. The morphological DRUJ type was not a significant factor. Arthritic changes were significantly more prevalent in patients with a shortening amount >4.5 mm and a union period <3.25 months.

CONCLUSIONS

Radiologic arthritic changes after USO, were associated with the presence of cystic changes in the lunate, a shortening amount (>4.5 mm), and early bony union (<3.25 months).

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic level III.

The influence of cartilage thickness at the sigmoid notch on inclination at the distal radioulnar joint

AIMS

The aims of this study were: firstly, to investigate the influence of the thickness of cartilage at the sigmoid notch on the inclination of the distal radioulnar joint (DRUJ), and secondly, to compare the sensitivity and specificity of MRI with plain radiographs for the assessment of the inclination of the articular surface of the DRUJ in the coronal plane.

PATIENTS AND METHODS

Contemporaneous MRI images and radiographs of 100 wrists from 98 asymptomatic patients (mean age 43 years, (16 to 67); 52 male, 53%) with no history of a fracture involving the wrist or surgery to the wrist, were reviewed. The thickness of the cartilage at the sigmoid notch, inclination of the DRUJ and Tolat Type of each DRUJ were determined.

RESULTS

The assessment using MRI scans and cortical bone correlated well with radiographs, with a kappa value of 0.83. The mean difference between the inclination using the cortex and cartilage on MRI scans was 12°, leading to a change of Tolat type of inclination in 66% of wrists. No reverse oblique (Type 3) inclinations were found when using the cartilage to assess inclination.

CONCLUSION

These data revealed that when measuring the inclination of the DRUJ using cartilage, reverse oblique inclinations might not exist. The data suggest that performing an ulna shortening osteotomy might be reasonable even in distal radioulnar joints where the plain radiographic appearance suggests an unfavourable reverse oblique inclination in the coronal plane. We recommend using MRI to validate radiographs in those that appear to be reverse oblique (Tolat Type 3), as the true inclination might be different, thereby removing one possible contraindication to ulnar shortening. Cite this article: Bone Joint J 2017;99-B:369-75.

A finite element model to investigate the effect of ulnar variance on distal radioulnar joint mechanics

Ulnocarpal impaction syndrome involves excessive loading of the ulnocarpal joint. Ulnar shortening osteotomies are an effective way to reduce ulnocarpal loading but alter contact mechanics at the distal radioulnar joint (DRUJ). This study used a computational model to investigate the relationship between ulnar length and DRUJ mechanics. Detailed, finite element models of the radius and ulna bones were constructed from magnetic resonance imaging data. The length of the ulna bone model was increased and decreased up to 5 mm in 1 mm increments. A computational model was used to predict joint contact at the DRUJ for each ulnar length. Lengthening the ulna caused a slight decrease in DRUJ contact pressure, with a more substantial decrease in contact area. Shortening the ulna caused a substantial increase in contact area, with a smaller increase in DRUJ contact pressure. The location of contact on the radial sigmoid notch changed with 2 mm lengthening and 3 mm shortening. The results of this study demonstrate the sensitivity of DRUJ contact to ulnar length changes, which may explain the DRUJ cartilage degeneration that often follows ulnar osteotomies. The joint contact model implemented in this study allowed the relationship between ulnar length and DRUJ contact to be examined systematically, in a way that is difficult to achieve through cadaveric experimentation. The results confirmed published experimental data showing an increased DRUJ contact pressure with ulnar shortening. It is important that clinicians consider the influence of ulnar osteotomies, not only on ulnocarpal loading but also on DRUJ mechanics. Copyright © 2016 John Wiley & Sons, Ltd.

Osseous Anatomy of the Distal Radioulnar Joint: An Assessment Using 3-Dimensional Modeling and Clinical Implications

PURPOSE

Using a novel technique, we assess and describe the distal radioulnar joint (DRUJ) anatomy. The purpose of this study was to provide the anatomic dimensions of the DRUJ and to evaluate contralateral symmetry.

METHODS

Computed tomography images of 100 cadaveric forearms were obtained. Three-dimensional models of the radius and ulna were generated and evaluated using 3-dimensional modeling software. Measurements of the radius of curvature of the sigmoid notch (SN) and ulnar head (UH), as well as the length of the SN and volar and dorsal lips were performed in the axial and coronal sequences. In addition, mid-coronal angular measurements were made of the SN and UH to quantify the obliquity of the DRUJ. All coronal measurements were performed with the forearm set to neutral rotation.

RESULTS

The average ulnar variance was -0.9 ± 1.8 mm. The radius of curvature of the UH (8.2 ± 1.3 mm) was markedly smaller than that of the SN (18.2 ± 8.5 mm). The length of the SN in coronal sequences increased from volar to dorsal by 65%. The mid-coronal angle (DRUJ obliquity) of the SN and UH measured 6.0 ± 9.9° and 18.0 ± 9.9°, respectively. A direct inverse correlation was demonstrated in the obliquity of the DRUJ and ulnar variance. All anatomic measurements were similar when comparing bilateral specimens.

CONCLUSIONS

The SN length tends to increase in size from volar to dorsal. Bilateral specimens from the same individual demonstrate similarities and can be cautiously used for comparison.

CLINICAL RELEVANCE

The relationships and measurements demonstrated in this study can be a guide when considering reconstructive procedures or dealing with complex fractures involving the DRUJ.

Distal Radioulnar Joint Reaction Force Following Ulnar Shortening: Diaphyseal Osteotomy Versus Wafer Resection

PURPOSE

To compare how ulnar diaphyseal shortening and wafer resection affect distal radioulnar joint (DRUJ) joint reaction force (JRF) using a nondestructive method of measurement. Our hypothesis was that ulnar shortening osteotomy would increase DRUJ JRF more than wafer resection.

METHODS

Eight fresh-frozen human cadaveric upper limbs were obtained. Under fluoroscopic guidance, a threaded pin was inserted into the lateral radius orthogonal to the DRUJ and a second pin was placed in the medial ulna coaxial to the radial pin. Each limb was mounted onto a mechanical tensile testing machine and a distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Data sets were entered into a computer and a polynomial was generated and solved to determine the JRF. This process was repeated after ulnar diaphyseal osteotomy, ulnar re-lengthening, and ulnar wafer resection. The JRF was compared among the 4 conditions.

RESULTS

Average baseline DRUJ JRF for the 8 arms increased significantly after diaphyseal ulnar shortening osteotomy (7.2 vs 10.3 N). Average JRF after re-lengthening the ulna and wafer resection was 6.9 and 6.7 N, respectively. There were no differences in JRF among baseline, re-lengthened, and wafer resection conditions.

CONCLUSIONS

Distal radioulnar joint JRF increased significantly after ulnar diaphyseal shortening osteotomy and did not increase after ulnar wafer resection.

CLINICAL RELEVANCE

Diaphyseal ulnar shortening osteotomy increases DRUJ JRF, which may lead to DRUJ arthrosis.

Comparison of plain x-rays and computed tomography for assessing distal radioulnar joint inclination

PURPOSE

To compare the inclination of the distal radioulnar joint (DRUJ) on computed tomography (CT) and plain radiography (XR) in order to assess the effect of narrowing the range of inclination used in the original Tolat classification system to identify potentially problematic reverse oblique DRUJs.

METHODS

Two independent investigators compared the angle of inclination and Tolat type on matched wrist XRs in the coronal plane and CTs of the same patients with normal DRUJs. The degree of agreement between XR and CT was determined. Inter- and intra-observer reliabilities were calculated. The prevalence of the 3 inclination types of the DRUJs using Tolat's definition was recorded. Their original quantitative definition of the parallel Tolat type 1 DRUJ included all DRUJs with a measured inclination of ±10°. We noted and compared the resultant changes in prevalence of the different DRUJ types after narrowing the inclination range to ±5° and ±3°.

RESULTS

Highly significant correlation between CT and XR measurements were found for both observers. Despite this, the limits of agreement between CT and XR in determining the sigmoid notch inclination was -9° to 11° (±2° standard deviations from the mean difference). When measured from the CTs and using Tolat's original algorithm, the prevalence of Tolat type 1 DRUJ was 47% (N = 34), type 2 was 51% (N = 37), and type 3 was 1% (N = 1). These percentages changed to 7% (N = 5) for type 1, 78% (N = 56) for type 2, and 15% (N = 11) for type 3 when applying narrower ranges of inclination.

CONCLUSIONS

Narrowing the range of sigmoid notch inclination that defines type 1 (parallel) DRUJs when using CT provided a more accurate representation of the morphological types. It revealed an increased number of potentially problematic type 3 DRUJs. However, the statistical limits of agreement between CT and XR suggested that high-resolution 3-dimensional imaging is required to apply the new algorithm.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Ulnar shortening osteotomy for malunited distal radius fractures: results of a 7-year follow-up with special regard to the grade of radial displacement and post-operative ulnar variance

INTRODUCTION

The treatment of ulnar-sided wrist pain after malunited distal radius fractures remains controversial. Radial corrective osteotomy can restore congruity in the distal radioulnar joint (DRUJ) as well as adequate length of the radius. Ulnar shortening osteotomies leave the radius' angular deformities unchanged, risking secondary DRUJ osteoarthritis. We supposed that, even within the widely accepted limit of 20°, a greater angulation of the radius in the sagittal plane correlates with a higher rate of DRUJ osteoarthritis. Furthermore, we suspected worse results from an ulna shortened to a negative rather than a neutral or positive ulnar variance.

MATERIALS AND METHODS

For this retrospective study, we reviewed 23 patients a mean 7.2 (range 5.6-8.5) years after ulnar shortening osteotomy for malunion of distal radius fractures. We compared 14 patients with up to 10° dorsal or palmar displacement from the normal palmar tilt of 10° to 9 patients with more than 10° displacement, and 15 patients whose post-operative ulnar variance was neutral or positive to 8 who had a negative one.

RESULTS

Ulnar-sided wrist pain decreased enough to satisfy 21 of the 23 patients. Clinical results tended to be better when radial displacement was minor and when post-operative ulnar variance was positive or neutral. A shorter ulna significantly increased the rate of DRUJ osteoarthritis, whereas a greater degree of radial displacement only increased the rate slightly.

CONCLUSIONS

Radial corrective osteotomy should be discussed as alternative when displacement of the radius in the sagittal plane exceeds 10°. The ulna should be shortened moderately to reduce the risk of osteoarthritis in the distal radioulnar joint.

Subluxation-related ulnar neuropathy (SUN) syndrome related to distal radioulnar joint instability

Ulnar neuropathy coexistent with distal radioulnar joint (DRUJ) instability has previously been observed in our practice. The aim of this study was to define this phenomenon and investigate the hypothesis that the cause of this intermittent, positional ulnar neuropathy is related to kinking of the ulnar nerve about the DRUJ. Ulna neuropathy was present in 10/51 (19.6%) of a historical cohort of patients who presented with DRUJ instability. Nine subsequent patients with DRUJ instability and coexistent ulnar neuropathy underwent 3-T magnetic resonance imaging to better understand the mechanism of the observed syndrome. Both 3D qualitative and quantitative analyses were used to assess the presence of nerve 'kinking', displacing the nerve from its normal course and causing nerve compression/distraction in the distal forearm and Guyon's canal. Results of the quantitative analysis were statistically significant (p < 0.05). The clinical features of the condition have been delineated and termed subluxation-related ulnar neuropathy or SUN syndrome. The imaging study was a level II diagnostic study.

Ulnar-sided wrist pain: evaluation and treatment of triangular fibrocartilage complex tears, ulnocarpal impaction syndrome, and lunotriquetral ligament tears

Ulnar-sided wrist pain is a common cause of upper extremity disability. Presentation can vary from acute traumatic injuries to chronic degenerative conditions. Because of its overlapping anatomy, complex differential diagnosis, and varied treatment outcomes, the ulnar side of the wrist has been referred to as the "black box" of the wrist, and its pathology has been compared with low back pain. Common causes of ulnar-sided wrist pain include triangular fibrocartilaginous complex injuries, lunotriquetrial ligament injuries, and ulnar impaction syndrome.

Long-term outcomes of ulnar shortening osteotomy for idiopathic ulnar impaction syndrome: at least 5-years follow-up

Background

There have been few outcomes studies with follow-up after performing ulnar shortening osteotomy for ulnar impaction syndrome. We investigated the long-term clinical and radiological outcomes of ulnar shortening osteotomy for the treatment of idiopathic ulnar impaction syndrome.

Methods

We retrospectively reviewed 36 patients who had undergone ulnar shortening osteotomy for idiopathic ulnar impaction syndrome for a mean follow-up of 79.1 months (range, 62 to 132 months). The modified Gartland and Werley scores were measured pre- and postoperatively. The radiographic parameters for the assessment of the distal radioulnar joint (DRUJ) as well as the relationship between these radiographic parameters and the clinical and radiological outcomes were determined.

Results

The average modified Gartland and Werley wrist score improved from 65.5 ± 8.1 preoperatively to 93.4 ± 5.8 at the last follow-up visit. The average preoperative ulnar variance of 4.7 ± 2.0 mm was reduced to an average of -0.6 ± 1.4 mm postoperatively. Osteoarthritic changes of the DRUJ were first seen at 34.8 ± 11.1 months follow-up in 6 of 36 wrists (16.7%). Those who had osteoarthritic changes in the DRUJ had significantly wider preoperative ulnar variance, a longer distal radioulnar distance and a greater length of ulnar shortening, but the wrist scores of the patients who had osteoarthritic changes in the DRUJ were comparable to those who did not have osteoarthritic changes in the DRUJ.

Conclusions

The clinical outcomes are satisfactory for even more than 5 years after ulnar shortening osteotomy for treating idiopathic ulnar impaction syndrome despite the osteoarthritic changes of the DRUJ. The patients who need a larger degree of ulnar shortening may develop DRUJ arthritis.

A biomechanical evaluation of the relative load change in the joints of the wrist with ulnar shortening: a 'handbag' model

The wrist joint is loaded not only while applying a proximally directed load but also, less obviously, while carrying a handbag. Ulnar shortening reduces pressure and relieves pain in the ulnocarpal joint. The present study evaluated the pressure distribution in the wrist joints with ulnar shortening and lengthening when applying traction to the flexed fingers while the fingers were loaded and unloaded. The compressive forces in the loaded wrist were distributed with 67% across the radiocarpal joint and 33% across the ulnocarpal joint. Shortening the ulna by 3 mm increased load in the radius to 80%. Lengthening of the ulna by 1 mm increased its load to 55%. The load share of the distal radioulnar joint was constant even when the ulna was shortened 3-4 mm. It seems advisable to shorten the ulna by 3 mm, since the increased load in the related joints are constant within a range of -2 to -4 mm.

Ulnar-sided wrist pain: evaluation and treatment of triangular fibrocartilage complex tears, ulnocarpal impaction syndrome, and lunotriquetral ligament tears

Ulnar-sided wrist pain is a common cause of upper-extremity disability. Presentation can vary from acute traumatic injuries to chronic degenerative conditions. Because of its overlapping anatomy, complex differential diagnosis, and varied treatment outcomes, the ulnar side of the wrist has been referred to as the "black box" of the wrist, and its pathology has been compared with that of low back pain. Common causes of ulnar-sided wrist pain include triangular fibrocartilage complex injuries, lunotriquetral ligament injuries, and ulnar impaction syndrome.

Ulnar shortening osteotomy for ulnar ideopathic impaction syndrome

Twenty-eight patients were treated by ulnar shortening osteotomy for static or dynamic ulnar impaction syndrome. Ulnar variance was measured on a true anteroposterior radiograph. There were 25 wrists that were too long, two neutral, and one that was short. Bones were shortened by a mean of 3.5 mm. Mean follow-up time was 29 months (range 7-60), all with confirmed consolidation. At final follow-up mean grip strength had improved from 67% to 75%, mean Disabilities of the Arm, Shoulder, and Hand (DASH) score from 40 (range 12-83) to 26 (range 0-61) and mean range of movement from 80% (range 40%-100%) to 88% (range 50%-100%). Smoking, age at operation, type of osteotomy (transverse or oblique), dominance of hand, and sex did not influence consolidation or functionality. Special attention was paid to the anatomy of the distal radioulnar joint and the inclination of the sigmoid notch of the radius. There was no correlation between the anatomy and the functional outcome scores. Mean consolidation time (10 months) (range 2-32) and return to work were longer than in similar studies. Our findings confirm the usefulness of ulnar shortening osteotomy in the relief of ulnocarpal impingement symptoms.

Ulnar-shortening effect on distal radioulnar joint pressure: a biomechanical study

PURPOSE

The ulnar-shortening procedure has been successfully used to relieve ulnar impaction syndrome and may help in stabilizing the distal radioulnar joint (DRUJ) by increasing the tension within the triangular fibrocartilage complex. This procedure, however, may increase pressure at the DRUJ and possibly induce degenerative changes in the joint. This study aimed to examine the changes in pressure at the DRUJ by simulating the ulnar-shortening procedure in intact and torn states of the triangular fibrocartilage complex.

METHODS

Seven fresh-frozen cadaver arms amputated at the midportion of the humerus were used. The ulna and humerus were affixed firmly to a custom mount that allowed 60 degrees forearm rotation. An external fixator was attached to the distal ulna, leaving a 10-mm space to allow progressive shortening. Pressure sensors were inserted in the DRUJ, and pressure distribution in the joint was recorded after every 1-mm shortening that was performed up to a maximum of 6 mm with or without the application of muscle load. These data were then compared with those obtained with the original length of the ulna in 3 joint positions: neutral, 60 degrees pronation, and 60 degrees supination. The tests were repeated after sectioning either the dorsal or the palmar portion of the radioulnar ligament (RUL) and finally after complete sectioning of the RUL.

RESULTS

The peak pressure at the DRUJ increased notably in the intact specimens during progressive ulnar shortening. Compared with the intact specimens, those with partial RUL sectioning exhibited a smaller increase in the peak pressure with ulnar shortening. Complete sectioning of the RUL at its attachment to the ulnar fovea resulted in even smaller increases.

CONCLUSIONS

The greater the amount of ulnar shortening, the higher is the peak pressure at the DRUJ. The amount of ulnar shortening should be carefully planned to avoid excessive pressure at the DRUJ.

Factors affecting results of ulnar shortening for ulnar impaction syndrome

Although ulnar shortening osteotomy is the most frequently performed operation for ulnar impaction syndrome, little attention has been given to detect certain preoperative factors affecting clinical outcomes of this procedure. We asked whether preoperative factors influenced the postoperative score of ulnar shortening osteotomy combined with arthroscopic debridement of the triangular fibrocartilage complex. We retrospectively reviewed 51 patients (53 wrists) with ulnar impaction syndrome treated with this procedure. There were 28 males and 23 females ranging in age from 14 to 67 years (mean, 37.5 years). The minimum followup was 12 months (mean, 26.3 months; range, 12-95 months). At last followup, we determined a modified Mayo wrist score for each patient. Preoperative factors affecting the clinical score were identified using multiple regression analysis. The clinical score ranged from 40 to 100 points (mean, 84.5 points). A long duration of symptoms and workers' compensation predicted worse clinical scores. We recommend considering these two factors when deciding whether to perform this procedure.

Ulnar shortening effect on distal radioulnar joint stability: a biomechanical study

PURPOSE

The ulnar-shortening procedure has been adopted widely to reduce pressure between the ulna and ulnar carpus in ulnocarpal abutment syndrome. The hammock-like structure of the triangular fibrocartilage complex (TFCC), which supports and connects the ulnocarpal and distal radioulnar joint (DRUJ), variably is torn in this condition. The degree to which the torn TFCC may be tensioned to restabilize the DRUJ with ulnar recession is uncertain. This study examined changes in the stabilizing effect of the ulnar-shortening procedure in several TFCC tear conditions.

METHODS

Six fresh-frozen cadaver arms amputated at the midportion of the humerus were used. The skin, muscles, and capsuloligamentous structures below the elbow all were preserved. The ulna and humerus were affixed firmly to a custom mount that allowed 60 degrees of forearm rotation. An external fixator was attached to the distal ulna leaving space for a 10-mm resection of the ulna to allow progressive shortening. The radius was attached to a materials testing machine. The load-displacement curves were obtained while translating the distal radius dorsally or palmarly with respect to the ulna at 1.25 mm/s. Stiffness in dorsopalmar displacement was recorded at 1-mm intervals through 6 mm of length. These measurements then were compared with controls (0 mm shortening of the intact specimens) at 60 degrees pronation, neutral position, and 60 degrees supination. The tests then were repeated after sectioning either the dorsal or palmar portion of the radioulnar ligament (RUL) and then after complete sectioning of the RUL. Each portion was sectioned at its attachment to the ulnar fovea.

RESULTS

The stiffness of the DRUJ increased significantly in all 3 rotatory positions after shortening the ulna. A shortening of 6 mm resulted in a 26% to 44% increase in DRUJ stiffness. The stiffness decreased after partial sectioning of the RUL but increased with further ulnar shortening in all 3 positions. The DRUJ stiffness with the partially sectioned RUL after a shortening of 3 to 6 mm was as large as that of the intact specimens. The stiffness of the DRUJ after the complete section of the RUL was significantly smaller than that of the intact specimens even after shortening of 6 mm.

CONCLUSIONS

The ulnar-shortening procedure can stabilize the DRUJ by increasing intrastructural tension of the TFCC, only when the RUL is attached totally or partially to the ulnar fovea. If the RUL is avulsed completely then stability of the DRUJ no longer is obtained by the ulnar-shortening procedure.

Dynamic effects of joint-leveling procedure on pressure at the distal radioulnar joint

PURPOSE

Wrist joint-leveling procedures for decompression of the radiocarpal and ulnocarpal joints are accompanied by the risk for subsequent disorders of the adjacent distal radioulnar joint (DRUJ). This study evaluated the dynamic change of the pressure pattern at the DRUJ after joint-leveling procedures.

METHODS

Thirteen fresh-frozen adult cadaveric upper extremities were used. A segment of the radius was excised at its midshaft to allow lengthening and shortening via a mini external fixator attachment. Dynamic pressure sensors were inserted into the DRUJ and the ulnocarpal joint. Axial loads were applied to the extensor carpi radialis brevis, extensor carpi radialis longus, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris for a total of 89 N with or without 30 N of radioulnar loading. The dynamic pressure distribution for full range of forearm rotation was recorded from 6 mm of radial shortening to 6 mm of radial lengthening in increments of 1 mm.

RESULTS

The peak pressures at the DRUJ before the joint-leveling procedures averaged 3.3 MPa without radioulnar loading and 5.0 MPa with radioulnar loading. The peak pressures with axial and radioulnar loading increased 85% at 6 mm of lengthening and only 8% at 6 mm of shortening. The peak pressures at the DRUJ for radial lengthening of 4 mm or more were significantly greater than that of the original length. Pressure at the ulnocarpal joint increased in proportion to the amount of radial shortening and decreased with radial lengthening.

CONCLUSIONS

Radial lengthening but not radial shortening significantly increases the peak pressure at the DRUJ.

Patterns of subchondral bone mineralization in the distal radioulnar joint

PURPOSE

Studies have shown that it is possible to derive direct knowledge about the actual mechanical conditions of the wrist by analyzing the subchondral mineralization. The aim of the present study was to evaluate the distribution of the subchondral bone mineralization of the distal radioulnar joint (DRUJ) noninvasively in living subjects by using computed tomography (CT) osteoabsorptiometry to gain new information about the long-term loading conditions.

METHODS

Twenty-two wrist joints were investigated in 11 healthy young subjects by means of CT osteoabsorptiometry. The CT scans of the DRUJ were taken in the axial plane in neutral position of the forearm and in both maximum pronation and supination. The CT datasets of 1.5-mm sections were obtained and then transferred to an image-analyzing system. The subchondral bone plate in each section was isolated, reconstructed in 3 dimensions, and converted into a false color series.

RESULTS

The maximum subchondral bone density in the sigmoid notch of the radius was found along the distal border in all wrists. It was located dorsally in 10 wrists, palmarly in 8 wrists, and centrally in 4 wrists. The maximum bone density on the corresponding articular surface of the ulna was found dorsally in 10 cases, centrally in 8 cases, and palmarly in 4 cases. In 13 cases the maximum bone density was found in direct opposition on radius and ulna in neutral position. A statistically significant difference could not be detected in subjects with an ulna minus variance nor in those with a DRUJ angulation greater than 10 degrees .

CONCLUSIONS

Our results show that in the sigmoid notch the load is transmitted through either the dorsal or palmar parts of the joint. In contrast the maximum bone density on the side of the ulna was found dorsally and centrally. We conclude that the ulna receives the maximum load in neutral position and supination, whereas because of the dorsopalmar translation of the ulnar head the radius may lead the ulna with either its palmar or dorsal borders during pronosupination. The ligamentous apparatus, the shape of the joint, and the ulna variance, however, may influence load transmission.

MR imaging findings in ulnar-sided wrist impaction syndromes

Ulnar-sided wrist impaction syndromes are a common source of ulnar pain and limitation of motion. These conditions refer to a group of pathologic entities that result from repetitive or acute forced impaction between the distal ulna and ulnar carpus or distal radius and surrounding soft tissues. MR imaging allows earlier detection of the bone and soft-tissue lesions that are present in the different ulnar-sided wrist impaction syndromes and is helpful in formulating the extensive differential diagnosis in patients with ulnar wrist pain and limitation of motion.

Relationship between joint laxity and radio-ulno-carpal joint morphology

The relationships between wrist laxity, ulnar variance, sigmoid notch inclination, and lunotriquetral motion were analysed in 60 normal volunteers. A strong correlation between ulnar length and sigmoid notch inclination was found for the entire group. Joint laxity was found to correlate with ulnar variance and lunotriquetral mobility in women, but not in men. The greater the laxity, the shorter the ulna and the greater the lunotriquetral motion during radial to ulnar deviation. These results support the concept that laxity increases the vulnerability of the wrist to injury.