Ultrasonic Evaluation of the Flexor Pollicis Longus Tendon Following Volar Plate Fixation for Distal Radius Fractures

Changes in Distance Between the Flexor Pollicis Longus Tendon and Volar Locking Plate: An Ultrasonographic Study

PURPOSE

Flexor pollicis longus rupture is a major complication after volar locking plate fixation of distal radius fractures. Although the distance between the flexor pollicis longus tendon and the plate (plate-tendon distance) measured by ultrasonography is used to predict tendon rupture risk, the timing of the ultrasonography can affect the measurements. Therefore, this study aimed to analyze the chronological change of the plate-tendon distance between the tendon and plate.

METHODS

A total of 166 wrists underwent the plate-tendon distance measurement twice or more times within 15 months after surgery. Longitudinal ultrasonography scans with the wrist in a neutral position and the thumb flexed were used to measure the plate-tendon distance. The plate-tendon distances at 0-5 months, 5-10 months, and 10-15 months after surgery were compared. A multiple linear regression analysis was performed to evaluate the influence of the interval between surgery and examination, Soong grade, and plate type on the plate-tendon distance.

RESULTS

The plate-tendon distance decreased as the interval between surgery and examination increased. The plate-tendon distance was an average of 2.0 ± 1.1 mm, 1.4 ± 0.9 mm, and 1.2 ± 0.9 mm at 0-5 months, 5-10 months, and 10-15 months after surgery, respectively. Significant differences were observed between 0-5 months and 5-10 months and between 5-10 months and 10-15 months after surgery. A multiple linear regression showed that significant predictors of the plate-tendon distance were the intervals between surgery and examination and Soong grade.

CONCLUSIONS

The plate-tendon distance decreased as the time since surgery increased. When ultrasonography is used for the assessment of tendon rupture risk, it should be considered that the plate-tendon distance decreases as the interval between the surgery and examination increases.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognosis IV.

Diagnostic ultrasound of tendon injuries in the setting of distal radius fractures

OBJECTIVE

Describe tendon injuries and their structural causes seen on ultrasound in wrists with distal radius fractures and estimate the accuracy of ultrasound and its impact on clinical management.

MATERIALS AND METHODS

Ultrasounds of 226 wrists (221 patients) with distal radius fractures were retrospectively reviewed. Ultrasound findings of tendon injuries and their structural causes were correlated with surgery and clinical outcome. Accuracy and inter- and intra-observer reproducibilities were calculated.

RESULTS

Twenty-five wrists were treated non-operatively while 201 underwent surgery. Ultrasound demonstrated hardware contact with flexor pollicis longus (FPL) in 76 wrists, extensor pollicis longus (EPL) in 21, and other tendons in 94. Ultrasound identified tendon ruptures in 23 wrists (13 EPL/8 FPL/2 extensor indicis proprius (EIP)), most of which were surgically confirmed. Among 12 wrists with confirmed EPL ruptures, distal radius fracture had been treated with volar plating in 6 and non-operatively in 6, and ultrasound showed osseous irregularity at the rupture site in 8. All FPL ruptures occurred in wrists with volar plating. Ultrasound findings were concordant with subsequent clinical management in most. In 2, ultrasound findings led to the decision to remove hardware despite lack of symptoms. Ultrasound had sensitivity/specificity/accuracy of 88/99/98% for identifying a specific tendon as ruptured and 88/87/88% for tendon abnormalities in general. Inter- and intra-observer reproducibilities were excellent (kappa = 0.85 ~ 1.0).

CONCLUSION

Certain wrist tendons, particularly EPL and FPL, are vulnerable after distal radius fractures. Ultrasound is accurate and useful for detecting tendon injury and sources of tendon irritation and can guide clinical management.

Evaluation of the Coronal Malposition of the Volar Locking Plate in the Treatment of Distal Radius Fractures

Background and objectives: Literature does not show any studies regarding plate placement problems in the coronal plane of patients with volar plating due to distal radius fracture diagnosis. We aimed to investigate the functional and laboratory results of the coronal malposition of the volar locking plate in patients with distal radius fracture treated with internal fixation.

Methods: In this retrospective study, we included patients who had volar plate fixation, were aged between 18 and 80, had no pathological fracture, had a minimum of six months of follow-up, and had the same rehabilitation protocol. We consider the angle subtended on the coronal axis between the distal radius long axis and the distal radius locking plate as coronal malposition. We named the coronal malposition angle the "AYE Angle." Patients with an AYE angle of over 1 degree were evaluated under group 1. Patients with an AYE angle of 0-1 degrees were evaluated under group 2. Radiological parameters were taken from AP-Lateral X-ray views. Superficial University System of Georgia (USG) examinations were applied to detect tendon problems. The DASH and QUICK-DASH scoring systems were used for clinical evaluation. Grip strength was measured with a dynamometer in all patients. All results were compared between the two groups.

Results: Thirteen patients were female and 27 patients were male. Nineteen patients who had coronal malposition were added to group 1, while 21 patients who had no coronal malposition were added to group 2. Fifteen patients had normal USG results in group 2, while 18 patients had edema around the flexor pollicis longus (FPL) tendon as a result of USG in group 1. Statistically, a significant difference was detected between the two groups in terms of the amount of tenosynovitis around FPL (p=0.01).

A statistically significant relationship was found between USG grading and malposition grading. The study revealed that a higher rate of USG grade 2 was found in patients with malposition grade 2 (90.9%), while a higher rate of USG grade 1 (50%) was observed in patients with malposition grade 1 (p=0.01).

A statistically significant difference was not found between Soong grading and USG in terms of the level of tenosynovitis around the FPL tendon. The amount of tenosynovitis detected around the FPL tendon was 62.5% for Soong and grade 0 level, 60.7% for grade 1 level, and 50% for grade 2 level. There was no statistically significant difference between the two groups in the DASH and QUICK-DASH scoring systems (p=0.96). There was no statistically significant difference between the two groups in the grip strength (p=0.52).

Conclusion: Coronal plate position in the treatment of the distal radius fracture is important to avoid potential flexor tendon problems. The volar plate position should be adjusted properly both in the coronal and sagittal axes.

Radiography of the Distal Radius

Imaging of the distal radius is of paramount importance in diagnosing injuries, indicating patients for operative or nonoperative treatment, and appropriately following patients for associated injuries and complications. Plain radiographs and fluoroscopy are the dominant imaging modalities in all settings because they are readily available and provide valuable information about the osseous structures and any instrumentation. Computed tomography can offer more information about implant placement and the level of comminution of the articular surfaces but is more expensive and exposes patients to higher doses of radiation. Magnetic resonance imaging is less commonly used but is useful for occult fractures and other associated injuries. Ultrasonography is gaining popularity in evaluating implant placement, especially regarding tendon impingement and subsequent tendon injury.

Shear Wave Elastography (SWE) Evaluation of Asymptomatic Flexor Pollicis Longus Tendon Condition After Volar Plate Fixation for Distal Radius Fracture

Objective

This study aimed to evaluate asymptomatic flexor pollicis longus (FPL) tendon condition after volar plate fixation for distal radius fracture using shear wave elastography (SWE).

Methods

We evaluated 36 distal radius fractures with shear wave elastography to evaluate the FPL tendon after volar plate fixation. Ultrasonography was used to measure the FPL distance to the volar plate in the involved wrists, and the thickness of the FPL tendon in the involved wrists was measured on SWE sonograms taken 12 months postoperatively. Measurements of the involved wrists were compared with those of the intact wrists. The radiographic parameters and Soong grade were collected to analyze the correlation between these indicators and the value of the Young’s modulus and asymptomatic tendon injury.

Results

The mean values of the Young’s modulus for involved wrist were lower than for intact wrist tendons. The values of the Young’s modulus were correlated with the FPL distance, radial inclination, and Soong grade. FPL tendons of involved wrists exhibited in the majority a yellow (intermediate) SWE signal, compared to intact wrist tendons, which exhibited a red (hard) signal in the vast majority, and there were significant differences between the involved and intact wrist.

Conclusion

FPL tendon may develop asymptomatically changes after volar locking plate fixation of distal radius fractures, which can be detected by SWE effectively. FPL distance, radial accretion, and Soong grade may be the main causes of asymptomatic FPL tendon erosion.

Comparison of clinical outcomes with and without volar lunate facet fragments in dorsal displaced distal radius fractures

Introduction: Although many clinical studies about distal radius fracture (DRF) accompanied by volar lunate facet fragments (VLFF) have recently been reported, none focus on the direction of displacement of distal fragments. Many previous cases with difficulty in treating DRF with VLFF were volar-displaced fractures. Thus, the postoperative risk for re-displacement is different between volar- and dorsal-displaced fractures with VLFF. The aim of this study is to compare the outcome of dorsal-displaced fractures treated using proximal volar locking plates (PVLP) between those with VLFF and those without, in order to reconsider the indications of distal volar locking plates (DVLP) and investigate the possibility of treating dorsal-displaced DRF with VLFF using PVLP. Methods: The subjects were 122 patients with dorsal-displaced DRFs treated using PVLP (42 males and 80 females, mean age: 59.2 years old). The patients were divided into 13 patients with VLFF group and 109 patients without VLFF group, and the clinical outcomes at 12 months after surgery were compared. Results: No significant difference was noted on any evaluation between the groups. In addition, no postoperative re-displacement of VLFF was observed and bone union was confirmed. Furthermore, no osteoarthritic change was noted in all patients. Conclusions: We confirmed that surgical treatment for dorsal-displaced DRF using PVLP is possible even in cases of DRF with VLFF. In addition, DVLP is an implant with a high complication risk; therefore, it may be necessary to reconsider the use of DVLP for dorsal-displaced DRF with VLFF treatable by PVLP.

Interpretations of the Term "Watershed Line" Used as Reference for Volar Plating

Objective  The objective of this systematic review is to provide an overview of all interpretations of the definition of the watershed line used in literature. Methods  The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed for this review. A comprehensive search was performed for definitions of the watershed line given in literature. A total of 32 studies giving an explicit interpretation of the definition of the watershed line or anatomical reference for plate positioning in writing and/or imaging were included. Results  In 32 studies, we found eight different landmarks used to refer to the watershed line or correct plate positioning. Five studies used two different soft tissue landmarks. Six different bony landmarks were described in 24 studies. These could further be subdivided into three anatomical interpretations, described in seven studies, in which the term "watershed line" is explained as a distinguishable anatomical line, and two surgical interpretations, described in 15 studies, which are purely reflecting the optimal location of the volar plate. One interpretation of the watershed line described in two studies combined both anatomical and surgical landmarks. Conclusion  The (mis)interpretation of the definition of the term "watershed line" as described by Orbay is subject to the type of landmarks and purpose used: soft tissue or bony landmarks and an anatomical or a surgical purpose. A clear distinction can be made between interpretations using bony landmarks, as the true watershed line is defined and definitions using soft tissue landmarks, which might represent the reference points surgeons use in clinical practice.

Complications after operatively treated distal radius fractures

In the recent years, treatment of distal radius fractures (DRF) has advanced considerably. Surgical fixation with palmar angular stable plate has gained popularity, due to a reported lower complication rate when compared to dorsal fixation. The type of trauma or injury, surgical procedure and impaired bone quality are all contributors to complications in DRF. The main aim of this review is to summarize the most common complications and possible therapeutic solutions. In addition, strategies for minimizing these complications will be discussed.

The Watershed Line of the Distal Radius: Cadaveric and Imaging Study of Anatomical Landmarks

Background  Placement of volar plates remains a challenge as the watershed line may not be an easy-identifiable distinct line intraoperatively. Objectives  The main objective of this article is to define how anatomical landmarks identifiable upon the volar surgical approach to the distal radius relate to the watershed line. Methods  We identified anatomical landmarks macroscopically upon standard volar approach to the distal radius in 10 cadaveric forearms and marked these with radiostereometric analysis (RSA) beads in cadaveric wrists. The RSA beads were then referenced against the volar osseous structures using quantification of three-dimensional computed tomography and advanced imaging software. Results  The mean measurements were the radial and ulnar prominences 11.1 mm and 2.1 mm proximal to the joint line of the distal radius, respectively. The interfossa sulcus was 0.3 mm proximal and 3 mm dorsal to the ulnar prominence. The watershed line was between 3.5 (minimal) and 7.6 (maximal) mm distal to the distal line of insertion of the pronator quadratus. Conclusion  The watershed line is situated distal to the pronator quadratus, but with a wide variability making it an impractical landmark for plate position. The osseous ulnar prominence is a good anatomical reference for safe plate positioning, as it is located on the watershed line and easily palpated at surgery. One should keep in mind the sulcus-the point on the watershed line where the flexor pollicis longus runs-can be situated just proximal to the ulnar prominence. Clinical Relevance  To provide anatomical landmarks that are easy to identify upon surgical approach without the direct need for intraoperative imaging.

Positioning of a Volar Locking Plate with a Central Flexor Pollicis Longus Tendon Notch in Distal Radius Fractures

Background  Volar locking plates with a central notch were designed to reduce the risk of flexor pollicis longus (FPL) tendon irritation after volar plating for distal radius fractures. Objective  The purpose of this study was to evaluate the course of the FPL tendon after FPL-plate osteosynthesis to identify a plate position that avoids an impingement with the FPL tendon. Patients and Methods  Nineteen patients treated with volar plating using an FPL plate for a distal radius fracture were evaluated. Transverse ultrasound images were used to assess whether the profile of the FPL tendon lied within the plate notch. The position of the FPL tendon on transverse ultrasound images was transferred onto postoperative dorsovolar X-ray images to define an FPL tendon corridor for a plate position not interfering with the FPL tendon. Results  The FPL tendon was aligned inside the plate notch completely in three cases, partially in 11 cases, and missed the notch in five cases. An FPL corridor was defined at the level of the watershed line with all FPL tendons being completely (74%) or partially (26%) aligned inside that corridor. There was a moderate correlation between the plate notch being positioned inside this corridor and the FPL tendon being positioned inside the plate notch ( r  = 0.49; p  = 0.033). Conclusion  It seems advantageous to place the plate notch within a corridor parallel to the radial shaft between the ulnar edge of the scaphoid tubercle and the scapholunate interval for the FPL tendon protection. Level of Evidence  This is Level IV study.

Ultrasound Evaluation of the Protector Role of the Pronator Quadratus Suture in Volar Plating

The main complication of volar locking plates for distal radius fractures is flexor tendon rupture. The flexor pollicis longus (FPL) is the most commonly ruptured. Repair of the pronator quadratus (PQ) is one of the ways to prevent tendon rupture. The main purpose of this series was to evaluate the role of PQ repair after volar plating to prevent flexor tendon rupture using ultrasound (US). This work was a mono-operator prospective series of 20 consecutive patients with volar locking plates for distal radius fracture between September 2014 and May 2015. The PQ was repaired in all patients. A clinical, ultrasound, and perioperative evaluation of the flexor tendon was performed by this same surgeon. There was no flexor tendon rupture or tenosynovitis. There were no type A cases, which are characterized by contact between the plate and the FPL, and mostly type C cases, which are characterized by no contact between the plate and the FPL on US imaging. The suture of the PQ was sustainable over time when we removed the plate. Pronator quadratus repair is one of the ways to prevent flexor tendon rupture after volar plating. The outward-running suture is an effective technique for repairing the PQ. Ultrasound may be helpful during follow-up to detect asymptomatic flexor tendon irritation.

The Effect of Plate Design on the Flexor Pollicis Longus Tendon After Volar Locked Plating of Distal Radial Fractures

BACKGROUND

Injury to and rupture of the flexor pollicis longus (FPL) tendon are known complications after volar locking plate fixation for distal radial fractures. Recent investigations have demonstrated that plate positioning contributes to the risk of tendon rupture; however, the impact of plate design has yet to be established. The purpose of this study was to compare FPL tendon-to-plate distance, FPL tendon-plate contact, and sonographic changes in the FPL tendon for 2 volar locking plate designs (ADAPTIVE compared with FPL) using ultrasound examination.

METHODS

We identified patients who underwent distal radial fracture fixation by 2 fellowship-trained hand surgeons with either standard (ADAPTIVE) or FPL plates. Patients were matched by age, sex, and Soong grade. Enrolled patients returned for a research-related office visit for a clinical examination and bilateral wrist ultrasound. We measured plate-tendon distance, plate-tendon contact, sonographic changes in the FPL tendon, and postoperative radiographic parameters in the operatively treated wrist and the uninjured wrist.

RESULTS

Forty patients with Soong grade-1 or 2 plate prominence underwent bilateral wrist ultrasound examination; all of the patients had distal radial fracture fixation, 20 with the standard volar locking plate and 20 with the FPL volar locking plate. Similar proportions of patients with the FPL plate (65%) and those with the standard plate (79%) had plate-tendon contact (p = 0.48); however, the FPL volar locking plate group had significantly less of the FPL tendon in contact with the volar plate than the standard volar locking plate group at wrist extension at both 0° (p < 0.001) and 45° (p < 0.001). There was no difference (p = 0.5) in the proportion of patients with sonographic changes in the FPL tendon between the FPL volar locking plate group (25%) and the standard volar locking plate group (21%). The postoperative volar tilt was significantly lower in patients with FPL plate-tendon contact (p = 0.01) and correlated moderately with the percentage of FPL tendon-plate contact at 0° (r = -0.51; p < 0.001) and 45° (r = -0.53; p < 0.001). There were no cases of tendon rupture in the cohort.

CONCLUSIONS

We found that the FPL volar locking plate and increased volar tilt significantly reduced the plate-tendon contact area compared with the standard volar locking plate. In our asymptomatic cohort, we were unable to find a difference in sonographic changes in the FPL tendon. Further studies are needed to determine the clinical importance of decreased tendon-plate contact area seen in modified volar locking plate designs.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of Levels of Evidence.

Volar locking plates not touching the flexor pollicis longus tendon appear as prominences on radiographs: a cadaver study

Background

Plate protrusion is a risk factor for flexor pollicis longus (FPL) rupture following volar locking plate (VLP) surgery. However, plate prominence on follow-up radiographs is common. We hypothesised that a VLP that does not touch the FPL tendon can appear as a plate prominence projected over the volar ridge on lateral radiographs.

Materials and methods

We studied six current designs of widely used plates in formalin-fixed cadavers. Each plate was placed in six cadavers. We analysed 36 different plate–cadaver combinations. The main aim of plate fixation was to position the plate in the most distal position without FPL tendon contact. Radiographs were obtained using fluoroscopy. We evaluated plate prominence from the volar ridge according to the Soong grading system.

Results

Soong grades 0 (plate did not extend beyond volar ridge), 1 (plate protruded beyond volar ridge) and 2 (plate directly on or located beyond the volar ridge) were observed in 23 (63.9%), 9 (25.0%) and 4 (11.1%) cadavers, respectively. VariAx, DVR and VALCP showed grade 1 prominence, whereas Acu-Loc2, HYBRIX and MODE showed grade 2 prominence.

Conclusions

Implant protrusion was observed in 36% of plate–cadaver combinations, even if the plate did not touch the FPL. Estimating the risk of FPL rupture using lateral radiographs alone is likely insufficient. Our findings can be applied to accurately identify the presence of implant prominence following VLP surgery.

Evaluation of the Acquisition of Ultrasound Proficiency in Hand Surgery Fellows

OBJECTIVES

To evaluate hand surgery fellow ultrasound (US) evaluations and performance of clinically relevant tasks after brief instruction.

METHODS

Six hand surgery fellows completed an US assessment and a survey on US use before and 1 month after a 30-minute US course.

RESULTS

The time to obtain an adequate image decreased from 4 minutes 42 seconds (4:42; range, 3:57-7:55) to 0:52 (range, 0:30-1:14; P < .001). Participants' performance for structure identification improved from 9.7 (range, 8-13) to 12 (range, 10-13) of 14 structures (P < .05). The average time to completion decreased from 14:6 (range, 12:08-18:30) to 9:34 (range, 4:40-15:54; P < .01). After instruction, all 6 participants identified and measured the cross-sectional area of the median nerve, identified and measured a zone 3 flexor tendon gap, and identified a simulated flexor digitorum profundus avulsion and its level of retraction (P < .05). Five of 6 successfully administered an US-guided injection to the extensor carpi ulnaris subsheath.

CONCLUSIONS

After a 30-minute instructional session, hand surgery fellows can achieve a basic level of US competency.

Investigating the minimum distance between the finger flexor tendons and distal radius during wrist and finger positions in healthy people

PURPOSE

Rupture of the flexor pollicis longus (FPL) and index flexor digitorum profundus (FDP2) tendons often occurs after locking plate fixation for distal radius fracture. This study aimed to determine the shortest tendon-radius distances of different hand positions.

METHODS

Fifty-nine hands of 30 healthy volunteers were studied. Distances between the FPL or FDP2 and distal radius were calculated in six wrist positions: 30° palmar flexion, neutral, 30° dorsiflexion, 60° dorsiflexion, maximum dorsiflexion, and 40° ulnar deviation with three finger positions (full extension and flexion of fingers, full flexion of the thumb or index finger, and full extension of the other four fingers). The shortest distance between the FPL or FDP2 and distal radius was noted.

RESULTS

The shortest distance between the FPL and distal radius was during maximum wrist dorsiflexion with isolated thumb flexion. The distance between the FDP2 and distal radius was shortest with all-finger flexion in 30° wrist dorsiflexion.

CONCLUSIONS

It is necessary to measure the distance between the FPL and distal radius in maximal wrist dorsiflexion with full flexion of the isolated thumb, as the shortest distance was observed with flexion of the isolated thumb. On the contrary, we recommend measuring the distance between the FDP2 and distal radius in 30° wrist dorsiflexion with flexion of all fingers.

Three-dimensional kinematics of the flexor pollicis longus tendon in relation to the position of the FPL plate and distal radius width

INTRODUCTION

The standard therapy of intra-articular and extra-articular distal radius fractures consists of open reduction and stabilization using palmar osteosynthesis with an angularly stable plate. The integrity of the flexor pollicis longus tendon (FPLT) may be mechanically affected by the plate, with rupture rates between 1 and 12% reported in the literature, occurring during a postoperative time period from 4 to 120 months. The aim of this study was to investigate the position of the tendon in relation to the distal edge of the plate using high-resolution ultrasonic imaging.

MATERIALS AND METHODS

Nineteen patients undergoing osteosynthesis for distal radius fracture in 2015 with the Medartis^® APTUS^® FPL plate were included in this study. Of these, seven dropped out for various reasons. Therefore,  twelve patients with a median age of 52 years (range 24-82 years) were included in the final analysis. High-frequency ultrasound was performed within a median of 28 (range 10-52) weeks by an experienced radiology specialist to locate the FPLT position in two separate wrist positions: (1) wrist held in 0° position and fingers extended and (2) wrist held in 45° of dorsal extension and actively flexed fingers II to V (functional position). For analysis, we used the axial ultrasound videos. Postoperative X-rays and CT scans were included for the analysis, especially the soft-tissue CT scan window for the exact localization of the FPLT.  Dynamic ultrasound scanning was used to localize the FPLT in relation to the plate in 0° and functional position of the hand. Using CT scanning, the position of the plate relative to the bone was determined. In this way, we were able to correlate the functional FPLT position with the osseous structures of the distal radius.

RESULTS

In all cases, the FPLT was positioned closer to the volar distal edge of the FPL plate in functional position than in 0° position. In four cases, the FPLT did not touch the plate at all and was shown to shift diagonally from radio-volar in ulno-dorsal direction during wrist movement from 0° to functional position, similarly to the sliding of the tendon in the assumed physiological motion sequence. In these cases, in the functional position the center of the FPLT was positioned slightly ulnarly of the center of the distal radius (i.e., less than 50% of the distal radius width measured from the radial border of DRUJ), and positioned more ulnarly than in all other cases (i.e., in which the FPLT came into contact with the plate). In the remaining two-thirds of the cases (eight patients), the FPLT touched the plate during wrist movement from 0° to functional position, shifted in dorsal direction and slid into the plate indentation, irrespective of whether the tendon entered the indentation from the radial or the ulnar side, and independent of the ulnoradial position of the plate. No signs of tendinopathy of the FPLT were found in any of the cases.

CONCLUSION

The results show that the indentation of the Medartis^® APTUS^® FPL plate reduces the tendon-plate contact and ideally even prevents it entirely. In particular, ulnar positioning of the plate lowers the risk of tendon-plate contact. If the FPLT touches the plate, the tendon pulls into the plate indentation, thus lowering the contact. Consequently, the Soong criteria are not applicable when a FPL plate is used.

Comparison of Intended Lengthening of Magnetically Controlled Growing Rods: Ultrasound Versus X-Ray

BACKGROUND

In the treatment of early onset scoliosis (EOS), there has been a trend to use magnetically controlled growing rods (MCGR) in order to reduce the number of surgeries. To confirm the amount of lengthening, spine radiographs were required. Recently, ultrasound (US) has been added to monitor lengthening of MCGR to avoid radiation exposure. Our aim was to determine whether US is as accurate as plain radiography (x-ray) in determining the amount of length achieved at individual MCGR lengthening episodes.

METHODS

Retrospective study; inclusion criteria: EOS cases with dual MCGR with minimum 12 months follow-up. Intended lengthening IL (mm), lengthening on US (mm) and x-ray (mm) were documented from medical records for both right and left rods. Primary (no surgery before MCGR) and conversion (other types of instrumentation were replaced with MCGR) cases were reviewed separately. P-values determined with analysis of variance.

RESULTS

Sixteen cases with 100 lengthening episodes met the inclusion criteria. Eleven were primary MCGR cases with 67 episodes. Mean follow-up was 19±5 months. Significant differences were found between IL (3.4±1 mm), US (2.7±1.9 mm), and x-ray (4.1±2.2 mm) (P<0.001). The difference between IL and x-ray was minimal, but statistically significant (P=0.046). US showed statistically lower values than both IL (P=0.001) and x-ray (P<0.001). The mean ratio of x-ray/IL, US/IL, and US/x-ray were 1.1, 0.75, and 0.84, respectively. Five conversion cases had 33 episodes. Mean follow-up was 21±2 months. Significant differences were found between IL (3.4±0.8 mm), US (1.3±0.8 mm), and x-ray (1.7±0.9 mm) (P<0.001) but there was no significant difference between US and x-ray (P=0.283). IL was significantly higher than both US (P< 0.001) and x-ray (P<0.001). The mean ratio of x-ray/IL, US/IL, and US/x-ray were 0.64, 0.41, and 1.1, respectively.

CONCLUSIONS

US can provide confirmatory information of noninvasive lengthening of MCGR. However, US tended to underestimate the achieved length as measured by x-ray in primary cases. Conversion cases demonstrate better concordance between US and x-ray but in these cases less overall length was achieved at each lengthening episode.

LEVEL OF EVIDENCE

Level III.

Flexor tendon complications in comminuted distal radius fractures treated with anatomic volar rim locking plates

OBJECTIVE

Anatomic volar rim locking plates are designed with the aim of treating intraarticular distal radius fractures. When used to treat comminuted distal radius fractures, these plates can damage the flexor tendons. In this study, we sought to determine the radiological and functional results and rate of complications of these plates.

METHODS

We retrospectively reviewed the records of 36 patients (28 males, 8 females; mean age: 46.4 years) with AO/OTA Type C2-C3 distal radius fractures treated with anatomic volar rim distal radius plates between January 2011 and December 2014. Radial length, radial inclination and palmar tilt were compared with the intact wrist. Results were evaluated with the Mayo wrist and Lidstrom scores. Complications were documented throughout the follow-up period of 23.8 (range: 12 to 48) months.

RESULTS

Postoperative measurements of the radial length, inclination and palmar tilt did not differ significantly. Mayo wrist and Lidstrom scores were good and excellent in 27 and 32 patients, respectively. Flexor tenosynovitis was symptomatic in 15 patients and asymptomatic (localized swelling only) in 21. Plates were removed from 15 patients due to symptomatic tenosynovitis and from six patients due to partial rupture of the flexor pollicis longus tendon. The flexor digitorum profundus tendon of the second finger was also partially ruptured in three patients.

CONCLUSION

Anatomic volar rim locking plates provide satisfying radiological and functional results in treating AO/OTA Type C2-C3 comminuted distal radius fractures. However, if these plates interfere with the union of the fracture, they should be removed to avoid potential tendon problems caused by their placement in the rim region.

LEVEL OF EVIDENCE

Level IV, Therapeutic study.