The severity of ulnar variance compared with contralateral hand: its significance on postoperative wrist function in patients with distal radius fracture

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.

Posttraumatic arthritis and functional outcomes of nonoperatively treated distal radius fractures after 3 years

Recent studies have shown that distal radius fractures (DRFs) in elderly patients can be treated nonoperatively with good functional results after 1 year. However, scientific evidence regarding longer follow-up to assess posttraumatic arthritis (PA), complications, and functional outcomes is scarce. This prospective case series aimed to evaluate these outcomes in a cohort of patients ≥ 65-year-old with nonoperatively treated DRFs after a minimum of 3 years. The primary outcome was PA. Secondary outcomes were complications, Quick Disabilities of the Arm, Shoulder and Hand Outcome Measure (QuickDASH), Patient-Rated Wrist/Hand Evaluation (PRWHE), pain, range of motion and grip strength. The full data of 32 patients with a mean follow-up of 3.3 years were available: 10/32 patients had radiological signs of PA, but only 2 of these patients reported pain. A total of 11/32 fractures healed in malunion (> 10° dorsal angulation). There was no significant difference in QuickDASH or PRWHE from 1 year to the latest follow-up after more than 3 years. This study thus adds to the literature stating that radiological signs, including PA and malunion, do not necessarily result in symptoms. Moreover, it underpins that nonoperative treatment of these patients results in good functional outcomes after 1 and 3 years.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL RELEVANCE

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

Use of Plain Radiography of Uninjured Wrists as Patient-Specific Markers of Successful Reduction of Unilateral Distal Radius Fractures

BACKGROUND

The standard of care of distal radius fractures requiring operative intervention involves restoration of anatomical alignment radiologically by comparing preoperative films and intraoperative fluoroscopy with established values based on population norms. The objective of this study is to evaluate the use of plain radiographs obtained from the uninjured wrist of patients who present with unilateral displaced distal radius fractures as a measure of successful achievement of anatomical realignment.

METHODS

A retrospective review was performed on 133 consecutive patients who presented from August 2020 to August 2021 with a diagnosis of unilateral distal radius fracture as confirmed on 3-view plain radiography. Patients who had bilateral radiographs and underwent open reduction and internal fixation were included. The primary outcome measure was comparison of radial inclination, radial height, tilt, and ulnar variance measured by 3 observers on preoperative, 1-week postoperative, and uninjured contralateral wrist films.

RESULTS

Twenty-one patients were included for analysis. Comparison of postoperative radiologic parameters with the contralateral uninjured extremity revealed a mean radial inclination difference of 3.8°, radial height difference of 2.0 mm, volar tilt difference of 6.3°, and ulnar variance difference of 0.9 mm. The average postreduction radial height was found to deviate from contralateral radial height significantly more than from the historic radial height parameter (2.0 vs 0.6 mm, P < .001).

CONCLUSION

Attempts at achieving distal radius fracture reduction to within historical normal limits may result in an increased deviation from patient-specific anatomical parameters, especially with respect to radial height.

Radial distraction may reduce the incidence of ulnar-sided wrist pain in ulna-plus morphology intraoperatively following distal radius fractures fixation

INTRODUCTION

Fixed-angle plate fixation can be an effective treatment for distal radius fractures (DRFs). However, patients with existing ulnar positive variance might be at risk of developing symptoms of ulnar-sided wrist pain (USWP). Ulnar shortening osteotomy (USO) is one of the main treatment options for USWP. We hypothesized that a limited radial distraction at the fracture site at the time of surgery for DRF would be functionally equivalent to an indirect USO and that if this were done in a patient with an ulnar plus morphology it could potentially decrease the risk of USWP.

METHODS

This retrospective study was conducted at a single institution and all the surgeries were performed by single surgeon. A total of 136 patients (92 women and 44 men) with a mean age of 55 years were enrolled with 57 patients in the distraction group (from 2014 to 2017) and 79 patients (from 2011 to 2013) in the non-distraction group. Patients were assessed USWP. Functional outcomes were assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, Visual Analogue Scale (VAS) for pain, grip strength, and range of motion for the wrist.

RESULTS

The mean follow-up was 37.9 months (range, 28-61 months). The radiographs at postoperative 2-year follow-ups showed the mean ulnar positive variance was 1.3 mm (range, 1-2 mm) in the distraction group and 3.5 mm (range, 2-5 mm) in the non-distraction group. The average of the distraction length was 2.32 mm (range, 2-3 mm). At the 2-year follow-ups, USWP presented in 7% (four patients) in the distraction group, which was significantly less than the incidence of 28% (22 patients) in the non-distraction group. The distraction group exhibited significantly better DASH scores and grip strength and less subsequent ulnar-shortening osteotomy for ulnar-sided wrist pain.

CONCLUSIONS

The radial distraction procedure performed during DRFs fixation could possibly reduce the occurrence of postoperative USWP and improve the functional outcomes.

LEVEL OF EVIDENCE

Level III, Therapeutic.

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.

Biomechanical function requirements of the wrist. Circumduction versus flexion/abduction range of motion

The biomechanical function of the wrist is widely assessed by measuring the range of motion (RoM) in two separate orthogonal planes: flexion-extension (FE) and radioulnar deviation (RUD). However, the two motions are coupled. The aim of this study is to compare wrist circumduction with FE and RUD RoM in terms of representativeness of the kinematic requirements for performing activities of daily living (ADL). To this end, the wrist motion of healthy participants was measured while performing maximum RoM in FE and in RUD, circumduction, and thirty-two representative ADL. Active and functional RoM (ARoM and FRoM) were computed in each plane, the evolving circumduction curves were adjusted to ellipses, and intensity maps representing the frequency of the coupling angles in ADL were plotted, both per ADL and globally for both hands. Ellipses representing different percentages of coupling angles in ADL were also plotted. Wrist circumduction fits the coupling angles measured in ADL better than ARoM or FRoM. As a novelty, quantitative data for both circumduction and the coupling angles required in ADL are provided, shedding light on the real biomechanical function requirements of the wrist. Results might be used to quantify mobility reduction and its impact on the performance of ADL, globally and per ADL, to enhance rehabilitation strategies, as well as in clinical decision-making, robotics, and prostheses.