Study of the position of six volar locking plates for distal radius fracture relative to the watershed line

INTRODUCTION

Volar plate malpositioning in the treatment of distal radial fracture can lead to tendinitis or even tendon tear, especially when the plate position is very distal. We studied the impact of design on plate position in the distal radius. The primary aim was to compare the position of six volar wrist plates relative to the watershed line using the Soong classification. The secondary objectives were to assess the epidemiology of volar locking plate fixation within the administrative Département of Finistère (northwestern France) and to study whether the type of fracture played a role in plate position.

HYPOTHESIS

The plate design itself influences positioning relative to the watershed line on the Soong classification.

MATERIALS AND METHODS

A total of 2723 volar locking plate fixation cases were analyzed and categorized according to the Soong classification. Plates used were divided into six groups based on design: Zimmer Biomet®, Newclip Technics®, Stryker®, Synthes®, Medartis® and Medartis® Footprint. The number of Soong 0 + 1 plates (i.e., plates graded 0 and 1 taken together) was determined for each design, then compared using the Marascuilo procedure with a significance level of α = 0.05.

RESULTS

On the Marascuilo procedure, we found significant differences in the number of Soong grade 0 + 1 plates. The Zimmer Biomet and Newclip Technics® plates were significantly more often proximal to the watershed line than the Synthes and Medartis Footprint plates. Plate position with the Medartis® design was significantly more proximal to the watershed line than for its companion design, the Medartis® Footprint plate. The rate of volar locking plate fixation of distal radial fractures over the past 10 years increased in Finistère. Also, the type of fracture affected the choice of plate when different designs were available within a hospital center (Medartis® Footprint plate used in 2R3A fractures).

CONCLUSION

Our study highlights a significant difference in volar locking plate position relative to the watershed line between the various models available. Plate design is a deciding factor when treating distal radial fracture, to avoid impingement when implant removal is not routinely planned.

LEVEL OF EVIDENCE: 3

Volar Locking Plate Fixation for Distal Radius Fractures Distal to the Watershed Line with an Intact Lunate Volar Rim

Background: We treated distal radius fractures (DRFs) beyond the watershed line without fracture of the lunate volar rim using a volar locking plate (VLP) and report the radiological and clinical outcomes at least 3 years after surgery. Methods: In 41 consecutive patients between January 2012 and August 2017, the fragment was composed of the radial styloid process (distal to the watershed line) and the lunate volar rim was intact. We evaluated demographic factors, radiological features and radiological/clinical outcomes at the final follow-up. Results: Twenty-nine patients were followed and evaluated. The mean follow-up period was 5.7 years. The mean patient age was 52.7 years and 24 patients had intracapsular intra-articular fractures. The fracture line was present in the lunate fossa in all patients. Twenty patients were classified as Soong grade 2, and five and four patients were grades 1 and 0, respectively. No radiological parameter (volar tilt, radial inclination, step-off and ulnar variance) was significantly different between the affected and contralateral normal sides. The mean visual analogue scale pain score and Disabilities of the Arm, Shoulder and Hand score, as well as the range of movement of the wrist, were not different between the affected and contralateral normal wrists. Finally, the grip strength on the affected side was 92% of the contralateral value. Major complications, such as nonunion, malunion and tendon rupture, were absent. Conclusions: DRFs distal to the watershed line with an intact lunate volar rim are rare and easy to miss. Careful inspection of 3D-CT images is necessary to determine these injuries, and the optimal choice for proper fixation of the fragment amongst the commercial VLPs would result in satisfactory radiological and clinical outcomes. Level of Evidence: Level IV (Therapeutic).

Functional outcomes following fixation of a marginal distal radius fracture with two commonly used volar locking plates: a retrospective cohort study

Introduction

The volar locking plate has been widely used for unstable distal radius fractures to provide early recovery of wrist function. Volar plate prominence to the watershed line has been reported to be related to flexor tendon irritation, and avoid implant prominence in this area was suggested. On the other hand, marginal distal radius fracture patterns required the plate to cross the watershed line, making conflict over plate positioning on marginal distal radius fractures. This study compared functional outcomes in patients with marginal distal radius fractures treated with two different implants.

Materials and methods

A retrospective study was conducted, all patients who received a Synthes 2.4 mm LCP or an Acumed Acu-Loc VLP between January 2015 and December 2018 were reviewed. The marginal distal radius fracture pattern was the most distal horizontal fracture line within 10 mm of the lunate fossa’s joint line. The primary outcomes including patient-reported pain scores, range of motion, and grip strength were assessed. Secondary outcomes included patient-based subjective satisfaction scores of the injured wrist and hand function. The Mayo Wrist Score and the requirement for a secondary procedure related to hardware complications were also recorded.

Results

Forty-two patients met our inclusion criteria. Twenty-one patients were treated with the Synthes 2.4 mm LCP, and 21 patients with the Acumed Acu-Loc VLP. The primary outcome revealed that post-operative range of motion (P = 0.016) and grip strengths (P = 0.014) were significantly improved in the Acu-Loc VLP group. The MAYO wrist score in the Acu-Loc VLP group was also significantly better (P = 0.006).

Conclusions

Despite advances in implant designs, flexor tendon irritation or rupture is still a complication following distal radius’s volar plating. We believe the Acumed Acu-Loc VLP design provided better functional outcomes than the Synthes 2.4 mm LCP if appropriately and carefully placed into its designed-for position. This positioning results in promising patient satisfaction when treating marginal distal radius fractures.

Flexor tendon rupture after volar plating of distal radius fracture: A systematic review of the literature

Flexor tendon rupture after volar plate fixation of distal radius fracture (DRF) is rare. There is no consensus as to how to prevent them. The aim of our study was to identify the pathological mechanisms, and to establish the clinical and epidemiological profile of patients suffering from this complication. We carried out a systematic review using the PubMed, Scopus and Cochrane databases. Studies were included if they described complete or partial flexor tendon rupture following volar plate fixation of DRF. Forty-six 46 were included, for a total of 145 patients were reported: 138 from the literature, and 7 from our personal experience. Etiology was usually mechanical, by impingement with either the plate or protruding screws. Plate impingement was due to positioning beyond the watershed line, consolidation with posterior tilt, plate thickness, or low palmar cortical angle. Mean patient age was 62.4 years (range, 23-89 years). Median postoperative interval was 8 months (range, 3-120 months). Flexor pollicis longus was the most frequently injured tendon. The plate should be positioned proximally to the watershed line if possible, to ensure good initial reduction. Hardware should be removed 4 months after surgery if the plate is causing impingement according to the Soong criteria or if signs of tenosynovitis appear.

Pronator quadratus repair after volar plate fixation in distal radial fractures: evaluation of the clinical and functional outcome and of the protective role on the flexor tendons-a randomized controlled study

The objective was to evaluate pronator quadratus (PQ) repair following volar plating of distal radial fractures on clinical and functional outcome, as well as flexor tendon friction, during the first 12 months in ideally positioned plates (Soong 0). Confounding factors like variation in plate positioning, anatomical consolidation of the fracture and associated lesions were excluded. Eighty patients were included with distal radius fractures treated by volar locking plate in Soong grade 0 position, who were randomized to group PQ repair and group no repair. Sixty-five patients completed the 1-year follow-up: group PQ repair (n = 35) and group no repair (n = 30). Primary outcomes included range of motion, grip strength, pain level and QuickDASH. Secondary outcomes included distance between flexor pollicis longus (FPL) and volar rim and the largest distance between FPL and plate (soft tissue thickness occupied by PQ), assessed by ultrasonography. Mobility, grip strength and QuickDASH revealed no significant differences, except extension was significantly higher only in first 3 months and radial deviation was significantly higher only at 6 weeks after PQ repair. Pain level was significantly lower after PQ repair only in the first 3 months. Distance between FPL and volar rim and the largest distance between FPL and plate were significantly higher after PQ repair. No friction contact between FPL and volar rim was measured in both groups at all measurement moments. Consequently, protective flexor tendon effect of PQ repair could consequently not be concluded. In conclusion, clinical and functional short term benefits, except improved wrist extension and reduced pain in the first 3 months, were not proven in this study. In Soong grade 0, PQ repair is probably not necessary to prevent flexor tendon pathology. In Soong grade 1 or 2, this is still to be investigated. LEVEL OF EVIDENCE: 2.

Juxta-articular Plate Fixation in Distal Radius Intra-articular Fractures with Accompanying Volar Free Fragments beyond the Watershed Line

Background

Although distal radius fractures (DRF) are common fractures, intra-articular comminuted DRF with volar free fragments are uncommon. There is considerable difficulty in the fixation of free fragments beyond the watershed line using the existing volar locking plate. We aimed to examine the efficacy and potential complications associated with the use of juxta-articular volar plates in intra-articular DRF accompanied by free fragments beyond the watershed line.

Methods

The patients were enrolled in a consecutive manner between 2007 and 2016. In cases of DRF with free fragments beyond the watershed line, we employed a 2.4-mm small fragment juxta-articular volar locking compression plate using a volar Henry approach. A total of 32 patients were included in this study. There were 15 males and 17 females with a mean age of 52.3 years (range, 33 to 69 years). The mean follow-up period was 14.5 months (range, 10 to 24 months). Preoperative radiographs and three-dimensional computed tomography images were used to analyze fracture patterns and assess the free fragments beyond the watershed line. The mean number of free fracture fragments beyond the watershed line was 2.33. Plain radiographs of immediate postoperative and last follow-up were used to confirm fracture union, incongruence, radial height, volar tilt, radial inclination, and arthritic changes. For functional assessment, we measured grip strength, range of motion (ROM), modified Mayo wrist score (MMWS) and determined Disabilities of Arm, Shoulder and Hand (DASH) scores at the last follow-up. Postoperative complications were monitored during the follow-up period.

Results

All patients obtained sound union without significant complications. At the last follow-up, 16 cases presented with an articular step-off of more than 1 mm (mean, 1.10 mm). The mean MMWS was 76.3 (range, 55 to 90), mean DASH score was 15.38 (range, 9 to 22), mean visual analogue scale score for pain was 1.2 and mean grip strength was 75.5% of the opposite side. The mean ROM was 74.3° for volar flexion and 71.5° for dorsiflexion.

Conclusions

In cases of intra-articular DRF with free fragments beyond the watershed line, a volar approach with use of a juxtaarticular plate provided favorable outcomes without significant complications.

Danger zones for flexor tendons in volar plating of distal radius fractures

PURPOSE

To define a danger zone for volar plates using magnetic resonance imaging by analyzing the position of the flexor tendons at risk around the watershed line.

METHODS

We analyzed 40 wrist magnetic resonance images. The location of the flexor pollicus longus (FPL) and index flexor digitorum profundus (FDPi) tendons was recorded at 3 and 6 mm proximal to the watershed line of the distal radius. We measured the distance between the volar margin of the distal radius and the FPL and FDPi tendons, and the coronal position of the tendons.

RESULTS

At a point 3 mm proximal to the watershed line, FPL and FDPi were located on average 2.6 and 2.2 mm anterior to the volar margin of the distal radius. This distance increased to 4.7 and 5.3 mm at a point 6 mm proximal to the watershed line. The FPL and FDPi were located at 57% and 42% of the total width of the distal radius from the sigmoid notch at 3 mm from the watershed, and at 66% and 46% at 6 mm from the watershed.

CONCLUSIONS

Surgeons should be aware of the close proximity of the flexor tendons to the volar cortex of the distal radius proximal to the watershed line and their radial to ulnar position. Three millimeters proximal to the watershed line, plate placement more than 2 mm anterior to the volar cortex or the use of plates thicker than 2 mm poses a high risk for directly contacting flexor tendons.

CLINICAL RELEVANCE

This article may prove to be helpful in avoiding flexor tendon injury during volar plate fixation.