Extrusion and meniscal mobility evaluation in case of ramp lesion injury: a biomechanical feasibility study by 7T magnetic resonance imaging and digital volume correlation

Introduction: The existing body of literature on the biomechanical implications of ramp lesions is limited, leaving a significant gap in our understanding of how these lesions impact joint kinematics and loading in the medial compartment. This cadaveric biomechanical study aims to address this gap by employing an innovative Digital Volume Correlation (DVC) method, utilizing 7 Tesla Magnetic Resonance Imaging (MRI) images under various loading conditions. The primary objective is to conduct a comprehensive comparison of medial meniscal mobility between native knees and knees affected by grade 4 ramp lesions. By focusing on the intricate dynamics of meniscal mobility and extrusion, this work seeks to contribute valuable insights into the biomechanical consequences of medial meniscus ramp lesions. Materials and methods: An initial set of 7T MRI imaging sessions was conducted on two intact native knees, applying load values up to 1500N. Subsequently, a second series of images was captured on these identical knees, with the same loads applied, following the creation through arthroscopy of medial meniscus ramp lesions. The application of DVC enabled the precise determination of the three components of displacement and spatial variations in the medial menisci, both with and without ramp lesions. Results: The measured directional displacements between native knees and injured knees indicate that, following the application of axial compression load, menisci exhibit increased extrusion and posterior mobility as observed through DVC. Discussion: Injuries associated with Subtype 4 medial meniscus ramp lesions appear to elevate meniscal extrusion and posterior mobility during axial compression in the anterior cruciate ligament of intact knees. Following these preliminary results, we plan to expand our experimental approach to encompass individuals undergoing weight-bearing MRI. This expansion aims to identify meniscocapsular and/or meniscotibial insufficiency or rupture in patients, enabling us to proactively reduce the risk of osteoarthritic progression.

Minimally Invasive Surgery for Posterior Spinal Instrumentation and Fusion in Adolescent Idiopathic Scoliosis: Current Status and Future Application

The posterior minimally invasive spine surgery (MISS) approach-or the paraspinal muscle approach-for posterior spinal fusion and segmental instrumentation in adolescent idiopathic scoliosis (AIS) was first reported in 2011. It is less invasive than the traditionally used open posterior midline approach, which is associated with significant morbidity, including denervation of the paraspinal muscles, significant blood loss, and a large midline skin incision. The literature suggests that the MISS approach, though technically challenging and with a longer operative time, provides similar levels of deformity correction, lower intraoperative blood loss, shorter hospital stays, better pain outcomes, and a faster return to sports than the open posterior midline approach. Correction maintenance and fusion rates also seem to be equivalent for both approaches. This narrative review presents the results of relevant publications reporting on spinal segmental instrumentation using pedicle screws and posterior spinal fusion as part of an MISS approach. It then compares them with the results of the traditional open posterior midline approach for treating AIS. It specifically examines perioperative morbidity and radiological and clinical outcomes with a minimal follow-up length of 2 years (range 2-9 years).

Meniscal injuries in skeletally immature children with tibial eminence fractures. Systematic review of literature

PURPOSE

Although the mechanisms of injury are similar to ACL rupture in adults, publications dealing with meniscal lesions resulting from fractures of the intercondylar eminence in children are much rarer. The main objective was to measure the frequency of meniscal lesions associated with tibial eminence fractures in children. The second question was to determine whether there is any available evidence on association between meniscal tears diagnostic method, and frequencies of total lesions, total meniscal lesions, and total entrapments.

METHODS

A comprehensive literature search was performed using PubMed and Scopus. Articles were eligible for inclusion if they reported data on intercondylar tibial fracture, or tibial spine fracture, or tibial eminence fracture, or intercondylar eminence fracture. Article selection was performed in accordance with the PRISMA guidelines.

RESULTS

In total, 789 studies were identified by the literature search. At the end of the process, 26 studies were included in the final review. This systematic review identified 18.1% rate of meniscal tears and 20.1% rate of meniscal or IML entrapments during intercondylar eminence fractures. Proportion of total entrapments was significantly different between groups (17.8% in the arthroscopy group vs. 6.2% in the MRI group; p < .0001). Also, we found 20.9% of total associated lesions in the arthroscopy group vs. 26.1% in the MRI group (p = .06).

CONCLUSION

Although incidence of meniscal injuries in children tibial eminence fractures is lower than that in adults ACL rupture, pediatric meniscal tears and entrapments need to be systematically searched. MRI does not appear to provide additional information about the entrapment risk if arthroscopy treatment is performed. However, pretreatment MRI provides important informations about concomitant injuries, such as meniscal tears, and should be mandatory if orthopaedic treatment is retained. MRI modalities have yet to be specified to improve the diagnosis of soft tissues entrapments.

STUDY DESIGN

Systematic review of the literature REGISTRATION: PROSPERO N° CRD42021258384.

Prediction of the 3D shape of the L1 vertebral body from adjacent vertebrae

The aim of treatments of vertebral fractures is the anatomical reduction to restore the physiological biomechanics of the spine and the stabilization of the fracture to allow bone healing. However, the three-dimensional shape of the fractured vertebral body before the fracture is unknown in the clinical setting. Information about the pre-fracture vertebral body shape could help surgeons to select the optimal treatment. The goal of this study was to develop and validate a method based on Singular Value Decomposition (SVD) to predict the shape of the vertebral body of L1 from the shapes of T12 and L2. The geometry of the vertebral bodies of T12, L1 and L2 vertebrae of 40 patients were extracted from CT scans available from the VerSe2020 open-access dataset. Surface triangular meshes of each vertebra were morphed onto a template mesh. The set of vectors with the node coordinates of the morphed T12, L1 and L2 were compressed with SVD and used to build a system of linear equations. This system was used to solve a minimization problem and to reconstruct the shape of L1. A leave-one-out cross-validation was performed. Moreover, the approach was tested against an independent dataset with large osteophytes. The results of the study show a good prediction of the shape of the vertebral body of L1 from the shapes of the two adjacent vertebrae (mean error equal to 0.51 ± 0.11 mm on average, Hausdorff distance equal to 2.11 ± 0.56 mm on average), compared to current CT resolution typically used in the operating room. The error was slightly higher for patients presenting large osteophytes or severe bone degeneration (mean error equal to 0.65 ± 0.10 mm, Hausdorff distance equal to 3.54 ± 1.03 mm). The accuracy of the prediction was significantly better than approximating the shape of the vertebral body of L1 by the shape of T12 or L2. This approach could be used in the future to improve the pre-planning of spine surgeries to treat vertebral fractures.

Percutaneous balloon calcaneoplasty versus open reduction and internal fixation (ORIF) for intraarticular SANDERS 2B calcaneal fracture: Comparison of primary stability using a finite element method

INTRODUCTION

Fractures of the calcaneus are common, with 65% being intra-articular, which can lead to a major impairment of the patient's quality of life. Open reduction and internal fixation with locking plates can be considered as gold-standard technique but has a high rate of post-operative complications. Minimally invasive calcaneoplasty combined with minimally invasive screw osteosynthesis is largely drawn from the management of depressed lumbar or tibial plateau fractures. The hypothesis of this study is that calcaneoplasty associated with minimally invasive percutaneous screw osteosynthesis presents biomechanical characteristics comparable with conventional osteosynthesis.

MATERIALS AND METHODS

Eight hind feet were collected. A SANDERS 2B fracture was reproduced on each specimen, while four calcanei were reduced by a balloon calcaneoplasty method and fixed with a lateral screw, four others were manually reduced and fixed with conventional osteosynthesis. Each calcaneus was then segmented for 3D finite element modeling. A vertical load was applied to the joint surface in order to measure the displacement fields and the stress distribution according to the type of osteosynthesis.

RESULTS

Analyses of the intra-articular displacement fields showed lower overall displacements in calcaneal joints treated with calcaneoplasty and lateral screw fixation. Better stress distribution was found in the calcaneoplasty group with lower equivalent joint stresses. These results could be explained by the role of the PMMA cement as a strut, enabling better load transfer.

CONCLUSION

Balloon Calcaneoplasty combined with lateral screw osteosynthesis has biomechanical characteristics at least comparable to locking plate fixation in the treatment of SANDERS 2B calcaneal joint fractures in terms of displacement fields and stress distribution under the premise of anatomical reduction.

Test characteristics of rasterstereography for the early diagnosis of adolescent idiopathic scoliosis

This study aimed to evaluate rasterstereography of the spine as a diagnostic test for adolescent idiopathic soliosis (AIS), and to compare its results with those obtained using a scoliometer. Adolescents suspected of AIS and scheduled for radiographs were included. Rasterstereographic scoliosis angle (SA), maximal vertebral surface rotation (ROT), and angle of trunk rotation (ATR) with a scoliometer were evaluated. The area under the curve (AUC) from receiver operating characteristic (ROC) plots were used to describe the discriminative ability of the SA, ROT, and ATR for scoliosis, defined as a Cobb angle > 10°. Test characteristics (sensitivity and specificity) were reported for the best threshold identified using the Youden method. AUC of SA, ATR, and ROT were compared using the bootstrap test for two correlated ROC curves method. Of 212 patients studied, 146 (69%) had an AIS. The AUC was 0.74 for scoliosis angle (threshold 12.5°, sensitivity 75%, specificity 65%), 0.65 for maximal vertebral surface rotation (threshold 7.5°, sensitivity 63%, specificity 64%), and 0.82 for angle of trunk rotation (threshold 5.5°, sensitivity 65%, specificity 80%). The AUC of ROT was significantly lower than that of ATR (p < 0.001) and SA (p < 0.001). The AUCs of ATR and SA were not significantly different (p = 0.115). The rasterstereographic scoliosis angle has better diagnostic characteristics than the angle of trunk rotation evaluated with a scoliometer, with similar AUCs and a higher sensitivity.

Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits

PURPOSE

The objective of this study was to analyze the intra- and interobserver variability of this measurement according to a strict methodology and on a representative sample of the general population, as well as to identify the possible difficulties of measurement in case of patellar or trochlear dysplasia.

METHODS

This observational study involved radiographic analysis by three independent observers of a total of 50 patients who had a loaded patellofemoral X-ray taken with the knee flexed to 45°. An initial reading was taken to measure the angle of the trochlear sulcus, the Merchant angle, and to classify the knees according to a possible trochlear dysplasia and/or patellar dysplasia according to Wiberg. A second measurement was then performed to analyze intraobserver agreement. Interobserver agreement was measured on all radiographic measurements (n = 100).

RESULTS

The Merchant patellofemoral congruence angle showed good intraobserver concordance ranging from 0.925 (95% CI 0.868-0.957) to 0.942 (95% CI 0.898-0.967), as well as interobserver concordance ranging from 0.795 (95% CI 0.695-0.862) to 0.914 (95% CI 0.872-0.942). Poor results were found in terms of interobserver concordance on the measurement of the Merchant angle in case of stage 3 Wiberg patella ranging from 0.282 (95% CI -0.920 to 0.731) to 0.611 (95% CI 0.226-0.892).

CONCLUSION

Congruence angle is one of most commonly used measurements for patellar tracking. However, the convexity of the patellar surface makes it difficult to identify the patellar apex on its intraarticular facet, making the measurement of the Merchant congruence angle unreliable and not very reproducible in cases of stage 3 Wiberg patella. Registration N°IRB 2021/139.

Osteoarticular Infections in Children: Accurately Distinguishing between MSSA and Kingella kingae

Introduction: Osteoarticular infections (OAIs) constitute serious paediatric conditions that may cause severe complications. Identifying the causative organism is one of the mainstays of the care process, since its detection will confirm the diagnosis, enable adjustments to antibiotic therapy and thus optimize outcomes. Two bacteria account for the majority of OAIs before 16 years of age: Staphylococcus aureus is known for affecting the older child, whereas Kingella kingae affects infants and children younger than 4 years old. We aimed to better define clinical characteristic and biological criteria for prompt diagnosis and discrimination between these two OAI. Materials and methods: We retrospectively studied 335 children, gathering 100 K. kingae and 116 S. aureus bacteriologically proven OAIs. Age, gender, temperature at admission, involved bone or joint, and laboratory data including bacterial cultures were collected for analysis. Comparisons between patients with OAI due to K. kingae and those with OAI due to S. aureus were performed using the Mann−Whitney and Kruskal−Wallis tests. Six cut-off discrimination criteria (age, admission’s T°, WBC, CRP, ESR and platelet count) were defined, and their respective ability to differentiate between OAI patients due to K. kingae versus those with S. aureus was assessed by nonparametric receiver operating characteristic (ROC) curves. Results: Univariate analysis demonstrated significant differences between the two populations for age of patients, temperature at admission, CRP, ESR, WBC, and platelet count. AUC assessed by ROC curves demonstrated an exquisite ability to discriminate between the two populations for age of the patients; whereas AUC for CRP (0.79), temperature at admission (0.76), and platelet count (0.76) indicated a fair accuracy to discriminate between the two populations. Accuracy to discriminate between the two subgroups of patients was considered as poor for WBC (AUC = 0.62), and failed for ESR (AUC = 0.58). On the basis of our results, the best model to predict K. kingae OAI included of the following cut-offs for each parameter: age < 43 months, temperature at admission < 37.9 °C, CRP < 32.5 mg/L, and platelet count > 361,500/mm3. Conclusions: OAI caused by K. kingae affects primarily infants and toddlers aged less than 4 years, whereas most of the children with OAI due to MSSA were aged 4 years and more. Considering our experience on the ground, only three variables were very suggestive of an OAI caused by K. kingae, i.e., age of less than 4 years, platelet count > 400,000, and a CRP level below 32.5 mg/L, whereas WBC and ESR were relatively of limited use in clinical practice.

Surgical Site Infections after Spinal Surgery in a Tropical Area: A Prospective Monocentric Observational Study

To date, no study has described the microbiological profile of surgical site infections (SSIs) after spine surgery in a tropical environment. The main objective of this study is to describe the microbiology and the risk factors of SSI after spinal surgery in a tropical climate. Our hypothesis is that the microbiology of SSIs in tropical areas is different to what is mainly described in temperate countries. As a consequence, the recommendation for antibiotic prophylaxis administered in the operative room, which mainly relays on the literature, might not be adequate in such countries. We included 323 consecutive patients who underwent a spinal intervention between 2017 and 2019, with a 2-year minimum follow-up. Objective ISO criteria were established in accordance with the criteria accepted by the Center of Disease Control in Atlanta. The identification of risk factors for SSI was carried out by uni- and multivariate analysis with a significance threshold of P < 0.05. The incidence of SSI was 7.7%. A total of 54.8% were in favor of a predominantly digestive origin of germs with an average of 1.68 bacteria found by ISO. Inadequate antibiotic prophylaxis was found in 54.8%. Age and body mass index were found to be independent risk factors for SSI. We report here an unusual microbiological profile of SSI with a predominance of gram-negative bacteria and a low proportion of Staphylococcus aureus and Staphylococcus epidermidis.

Study of Mechanical Behavior in Epiphyseal Fracture Treated by Reduction and Cement Injection: No Immediate Post-Operative Weight-Bearing but Only Passive and Active Mobilization Should be Advised

The development of new percutaneous treatment techniques using a balloon for the reduction and cement for the stabilization for tibial plateau fractures (TPF) are promising. The biomechanical changes brought by the cement in the periarticular fracture are unknown. The objective of this study was to provide elements of understanding of the bone behavior in an epiphyseal fracture treated with cementoplasty and to define the modifications brought about by the presence of this cement in the bone from both an architectural and biomechanical point of view.

In vitro animal experimentation was conducted. Bones samples were prepared with a cavity created with or without cancellous compaction, aided by balloon expansion following the same protocol as in the treatment of TPF. A uniaxial compression test was performed with various speeds and by using Heaviside Digital Image Correlation to measure mechanical fields. Preliminary finite element models were constructed with various boundary conditions to be compared to our experimental results.

The analysis of the images permits us to obtain a representative load vs. time response, the displacement fields, and the strain distribution for crack initiation for each sample. Microcracks and discontinuity began very early at the interface bone/cement. Even when the global behavior was linear, microcracks already happened. There was no strain inside the cement. The finite element model that matched our experiments had no link between the two materials.

In this work, the use of a novel correlation process highlighted the biomechanical role of the cement inside the bone. This demonstrated that there is no load transfer between bone and cement. After the surgery, the cement behaves like a rigid body inside the cancellous bone (same as a screw or plate). The cement provides good reduction and primary stabilization (mini-invasive approach and good stress distribution), permitting the patient to undergo rehabilitation with active and passive mobilization, but no weight-bearing should be authorized while the cortical bone is not consolidated or stabilized.

Percutaneous surgery with balloon for tibial plateau fractures, results with a minimum of 5 years of follow-up

Tibial plateau fracture is a frequent entity for which surgical management is difficult both surgically and postoperatively, with multiple complications and often delayed recovery. The challenge lies in the anatomical reduction of the joint, the limitation of complications and the rapid functional recovery. Tuberoplasty appears to be an innovative technique that meets current expectations. The objective is to evaluate the reliability of tuberoplasty in reducing surgical risks and improving postoperative clinical results. This single-centre retrospective study included 30 patients with depressed tibial plateau fractures who underwent tuberoplasty from September 2011 to March 2014. Reduction analysis was performed by comparing pre-operative and post-operative depression from computed tomography (CT) data. Clinical outcomes were assessed by measuring flexion joint ranges, time to weight-bearing, KOOS questionnaire and a pangonogram. The mean depression was 7.4mm pre-operatively and 2.6mm [0;9] post-operatively, with 47% (14/30) having a residual depression of 2mm or less. Mean flexion at 6 weeks was 103° [30; 130]. Partial and total weight-bearing were allowed on day 47 [3; 150] and day 58 [20; 150], respectively. The mean KOOS score was 25.43 [1.15; 62.30] at a minimum of 5 years after surgery and the mean axis was 176.54° [172; 180]. There was one case of thrombophlebitis and one sensory-motor deficit in the common fibular nerve territory. The reduction of the tibial plateau observed in our study from tuberoplasty is in line with the literature results obtained from a conventional approach. Our results indicate that tuberoplasty is stable in the long term, has good functional results and early recovery with few complications. This preliminary study presents results that need to be investigated in a prospective randomised double-blind study.

Varus malalignment of the lower limb increases the risk of femoral neck fracture: A biomechanical study using a finite element method

INTRODUCTION

The understanding of the stresses and strains and their dependence on loading direction caused by an axial deformity is very important for understanding the mechanism of femural neck fractures. The hypothesis of this study is that lower limb malalignment is correlated with a substantial stress variation on the upper end of the femur. The purpose of this biomechanical trial using the finite element method is to determine the effect of the loading direction on the proximal femur regarding the malalignment of the lower limb, and also enlighten the relation between the lower limb alignment and the risk of a femoral neck fracture.

METHODS

Ten segmentations of CT scans were considered. An axial compression load was applied to the femoral head to digitally simulate the physiological configuration in neutral position as well as in different axial positions in varus/valgus alignment.

RESULTS

The stress at the proximal femur changes as the varus _valgus angle does. It can be observed the smaller absolute stress at angle 10° (valgus) and the higher absolute stress at angle -10° (varus). The mean maximum von Mises stress value was 14.1 (SD=±3.48) MPa for 0°, while the mean maximum von Mises stress value was 17.96 MPa (SD=4.87) for -10° in varus. The fracture risk indicator of the proximal femoral epiphyses changes inversely with angle direction. The FRI was the highest at -10° and the lowest at 10°.

CONCLUSION

Based on the biomechanical findings and the fracture risk indicator determined in this preliminary study, varus malalignment increases the risk of femoral neck fracture. Consideration of other parameters such as bone mineral density and morphological parameters should also help to plan preventive medical strategy in the elderly.

Comanipulation Robotic Platform for Spine Surgery with Exteroceptive Visual Coupling: Development and Experimentation

In this paper, a novel surgical robotic platform intended to assist surgeons in cervical spine surgery is presented. The purpose of this surgery is to treat cervical spine instabilities. The surgical procedure requires drilling into specific region of the vertebrae in order to attach spinal implants and ensure a normal spacing between each vertebra. In this context, the proposed robotic platform allows to control and restrict surgeon's movements to a specific drilling direction set by the surgeon. The current platform is composed of a collaborative robot with 7 DoF equipped with a drilling tool and directly comanipulated by the surgeon. A motion capture system, as an exteroceptive sensor device, provides the robot controller with the movement data of the vertebra to be drilled. Robot Operating System (ROS) framework is used to enable real-time communication between the collaborative robot and the visual exteroceptive device. In addition, an implemented compliance control program allows to enhance the safety aspect of the robotic platform. Indeed, the collaborative robot follow the patient's movements while constraining the tool movements to an optimal trajectory as well as a limited drilling depth selected by the surgeon. The robot's elbow movements are also restricted by exploiting the null-space in order to avoid collisions with other equipment or medical team members. Experimental drilling trials have been performed by an orthopedic surgeon to validate the usefulness and different functionalities of the developed robotic platform, and provide that a collaborative robot can comply with spine surgery procedure.

Correlation of Isokinetic Testing and ACL Failure With the Short Graft Tape Suspension Technique at Six Months

Purpose

The objective of this study was to correlate the data of the 6-month postoperative isokinetic muscle evaluation before resuming sports activities with the occurrence of ACL reconstruction rerupture after semitendinosus short graft.

Methods

From 2015 to 2018, all patients who were operated for an ACL reconstruction with a short semitendinosus autograft (TLS System) and who performed isokinetic tests on dynamometer at their 6th postoperative month were included in this study. The follow-up was prospective with the measurement of epidemiological, radiographic, and isokinetic parameters at 6 months of the ACL reconstruction. The cohort was divided into 2 groups: one group without an ACL reconstruction rerupture (Group 1) and the second group with a rerupture (Group 2).

Results

One hundred and four patients were analyzed with an average follow-up of 42.3 months (Minimum: 24; Maximum: 63.5), of which 11 patients (10.6%) had an ACL reconstruction rerupture. Group 1 consisted of 93 patients with an average age of 26.5 ± 9.0 years old who did not have an ACL reconstruction rerupture with an average follow-up of 41.6 ± 12.1 months. Group 2 consisted of 11 patients with an average age of 22.7 ± 6.1 years old, who had an ACL reconstruction rerupture with an average follow-up of 44.8 ± 11.3 months. Concerning extension force recovery, the ratio between operated and healthy knee was 81.8% ± 32.0 for Group 1, and 53.4% ± 20.6 for Group 2 (P = .035). A statistically significant difference was also found (P = .0017) during 60°/s flexion isokinetic test between the two groups.

Conclusions

This study revealed a significant link between muscle weakness in flexion and extension during 60°/s isokinetic test at 6 months of ACL reconstruction and semitendinosus autograft rerupture. Patients with an ACL reconstruction retear had inferior muscle dynamometric recovery results at 6 months before resuming sports activities.

Level of Evidence

Level III, prognostic, retrospective cohort study.

Biomechanical analysis of the correlation between mid-shaft atypical femoral fracture (AFF) and axial varus deformation

Background

Atypical femoral fractures (AFF) are diaphyseal fractures of the elderly that occur at the end of a minor trauma. The objective of this biomechanical study, using finite element modelling, was to evaluate the variations of the femoral diaphysis fracture indicator according to the variations of the mechanical axis of the lower limb, which can explain all the different atypical fracture types identified in the literature.

Methods

In order to measure variations in stress and risk factors for fracture of the femoral diaphysis, the distal end of the femur was constrained in all degrees of freedom. An axial compression load was applied to the femoral head to digitally simulate the bipodal support configuration in neutral position as well as in different axial positions in varus/valgus (− 10°/10°).

Results

The maximum stress value of Von Mises was twice as high (17.96 ± 4.87 MPa) at a varus angle of − 10^° as in the neutral position. The fracture risk indicator of the femoral diaphysis varies proportionally with the absolute value of the steering angle. However, the largest simulated varus deformation (− 10°) found a higher risk of diaphysis fracture indicator than in valgus (10°).

Conclusions

Variations in the mechanical axis of the lower limb influence the stress distribution at the femur diaphysis and consequently increase the risk of AFF. The axial deformation in varus is particularly at risk of AFF. The combination of axial deformation stresses and bone fragility consequently contribute to the creation of an environment favorable to the development of AFF.

Trial registration: ‘retrospectively registered’.

Contribution of Minimally Invasive Bone Augmentation With PMMA Cement in Primary Fixation of Schatzker Type II Tibial Plateau Fractures

Background: The most common type of fracture of the lateral tibial plateau is the Schatzker type II split-depressed fracture. Minimally invasive surgery using balloon reduction appears to be very promising compared to the gold standard using a bone tamp. This surgery aims to have the best reduction and stabilization to benefit from an early passive and active rehabilitation to avoid stiffening and muscle wasting. Using a balloon for fracture reduction has allowed the use of semi-liquid Injectable Bone Cement (IBC) fillers. These fillers can be phosphocalcic or polymethyl methacrylate (PMMA). The latest recommendations on these IBCs in spinal surgery increasingly rule out phosphocalcic fillers because of their low mechanical strength.

Questions/purposes: 1) What is the mechanical influence of IBC filling (PMMA) regarding the split and depression components of a Schatzker type II fracture? 2) What is the mechanical influence of osteosynthesis regarding the split and depression components of a Schatzker type II fracture with or without PMMA filing in three different kinds of percutaneous fixations?

Methods: This biomechanical study was performed on 36 fresh frozen tibia/fibula specimens. Six groups were formed according to the type of percutaneous osteosynthesis or possible PMMA filling. Mechanical strength tests were carried out using a Unicompartmental Knee prosthesis and displacement components were measured on either side of the separation on the anterolateral facet by optical method.

Results: We found a significant difference between cementless and cemented osteosynthesis for depression fracture stabilization (difference −507.56N with 95% confidence interval [−904.17; −110.94] (p-value = 0.026)). The differences between the different types of osteosynthesis were not significant (p-value = 0.58). There was a significant difference between osteosynthesis without cement and osteosynthesis with cement on separation (difference −477.72N [−878.52; −76.93] (p-value = 0.03)). The differences between the different types of fixations were not significant regarding separation (p-value = 0.99).

Conclusion: PMMA cement significantly improves primary stability, regardless of the type of osteosynthesis for a Schatzker type II plateau fracture. Filling with PMMA cement during tuberoplasty seems to be a very promising strategy in association with percutaneous osteosynthesis to allow rapid recovery after surgery.

Professional Status of Persistent Spinal Pain Syndrome Patients after Spinal Surgery (PSPS-T2): What Really Matters? A Prospective Study Introducing the Concept of "Adapted Professional Activity" Inferred from Clinical, Psychological and Social Influence

Persistent Spinal Pain Syndrome Type 2 (PSPS-T2) represents a main cause of work disruption. Beyond its societal consequences, occupational inactivity is responsible for a major decrease in physical/mental health in individuals but remains poorly analyzed. We designed a study to prospectively examine Professional Status (PS) evolution and its association with key bio-psychological markers. Data from 151 consecutively included working-age PSPS-T2 patients were analyzed to determine the proportion of professional inactivity and the relationships between PS and Social Gradient of Health (SGH), Numeric Pain Rating Scale (NPRS), EuroQol 5-Dimensional 5-Level (EQ-5D-5L), Oswestry Disability Index (ODI), Hospital Anxiety and Depression Scale (HADS), and Fear-Avoidance Belief Questionnaire work subscale (FABQ-W). Despite optimized medical management, 73.5% of PSPS-T2 patients remained inactive after 1 year of follow-up/p = 0.18. Inactive patients presented a low SGH/p = 0.002, higher NPRS/p = 0.048, lower EQ-5D-5L/p < 0.001, higher ODI/p = 0.018, higher HADS-D/p = 0.019 and higher FABQ-W/p < 0.001. No significant mediation effect of FABQ-W on SGH consequences regarding PS was observed in our structural model/p = 0.057. The link between unemployment and bio-psycho-social pain dimensions appears bidirectional and justifies intense collaboration with social workers. Optimizing therapeutical sequencing towards personalized professional plans implies restoring "Adapted Physical Function" as an initial goal, and tailoring an "Adapted Professional Activity", matching with patient expectations and capabilities, as a final objective.

Development of Digital Twins to Optimize Trauma Surgery and Postoperative Management. A Case Study Focusing on Tibial Plateau Fracture

Background and context: Surgical procedures are evolving toward less invasive and more tailored approaches to consider the specific pathology, morphology, and life habits of a patient. However, these new surgical methods require thorough preoperative planning and an advanced understanding of biomechanical behaviors. In this sense, patient-specific modeling is developing in the form of digital twins to help personalized clinical decision-making.

Purpose: This study presents a patient-specific finite element model approach, focusing on tibial plateau fractures, to enhance biomechanical knowledge to optimize surgical trauma procedures and improve decision-making in postoperative management.

Study design: This is a level 5 study.

Methods: We used a postoperative 3D X-ray image of a patient who suffered from depression and separation of the lateral tibial plateau. The surgeon stabilized the fracture with polymethyl methacrylate cement injection and bi-cortical screw osteosynthesis. A digital twin of the patient’s fracture was created by segmentation. From the digital twin, four stabilization methods were modeled including two screw lengths, whether or not, to inject PMMA cement. The four stabilization methods were associated with three bone healing conditions resulting in twelve scenarios. Mechanical strength, stress distribution, interfragmentary strains, and fragment kinematics were assessed by applying the maximum load during gait. Repeated fracture risks were evaluated regarding to the volume of bone with stress above the local yield strength and regarding to the interfragmentary strains.

Results: Stress distribution analysis highlighted the mechanical contribution of cement injection and the favorable mechanical response of uni-cortical screw compared to bi-cortical screw. Evaluation of repeated fracture risks for this clinical case showed fracture instability for two of the twelve simulated scenarios.

Conclusion: This study presents a patient-specific finite element modeling workflow to assess the biomechanical behaviors associated with different stabilization methods of tibial plateau fractures. Strength and interfragmentary strains were evaluated to quantify the mechanical effects of surgical procedures. We evaluate repeated fracture risks and provide data for postoperative management.

Experimental validation of a new technique for the assessment of posterior tibial translation (ABC angle) after posterior cruciate ligament rupture

Background

The aim of this cadaver study was to evaluate an original technique for measuring posterior tibial translation based on an angle value instead of a distance value, with and without posterior stress application. It was hypothesized that an angle measurement of the posterior tibial translation would confirm the presence of a PCL tear with the knee flexed and completely extended.

Method

Using fresh cadavers, a set of strict lateral views were taken by fluoroscopy with the knee at 0°, 45° and 90° flexion on the intact knee and after transecting the PCL. The primary endpoint was the change in the posterior translation measured using a new technique, the ABC angle. This measurement was compared to the conventional posterior translation distance measurement with and without a posterior stress placed on the knee.

Results

Application of a posterior stress revealed clear changes in posterior translation after PCL transection with the knee at 0° for the angle technique and at 45° and 90° for the two techniques (p < 0.05). Contrary to the reference method, the ABC angle method found a statistically significant difference in posterior translation with the knee in extension.

Conclusion

Our technique provides a reliable radiographic measurement of posterior translation with the knee in extension, which should make it easier to acquire radiographs in patients who have pain with knee flexion. This angular measurement also has the advantage of not needing length calibration contrary to the reference technique.

Level of evidence

IV

Long-Term Efficacy of a Home-Care Hypnosis Program in Elderly Persons Suffering From Chronic Pain: A 12-Month Follow-Up

BACKGROUND

Pain is a major public health concern in the aging population. However, medication brings about negative effects that compel healthcare professionals to seek alternative management techniques to alleviate pain. Hypnosis has been recognized as an effective technique to manage pain, but its long-term efficacy has yet to be examined in older adults.

AIMS

The aim was to assess the effectiveness, over a 12-month period, of home-care hypnosis in elderly participants suffering from chronic pain.

DESIGN

Real-life retrospective one-arm study with a 12-month follow-up.

SETTINGS

Elderly Persons Suffering From Chronic Pain enrolled in a clinical health care program that offered home medical follow-up.

PARTICIPANTS/SUBJECTS

Fourteen elderly women (mean age 81 years) with chronic pain participated in the home-care hypnosis program. All participants presented chronic pain (≥6 months) with average pain score >4/10.

METHODS

Participants took part in seven 15-minute hypnosis sessions within 12 months. The Brief Pain Inventory questionnaire was used to evaluate pain perception and pain interference at baseline and at 3-, 6-, and 12-month follow-up period.

RESULTS

Hypnosis home-care program significantly decreased pain perception and pain interference compared to baseline after 3 months (-29% and -40%, p < .001), and remained lower at 6 (-31% and -54%, p < .001) and 12 (-31% and -47%, p < .001) months.

CONCLUSIONS

Seven sessions of 15 minutes allocated throughout a 12-month period produced clinically significant decreases in pain perception and pain interference. Hypnosis could be considered as an optimal additional way for health practitioners to manage chronic pain in an elderly population with long-term efficacy. This study offers a new long-term option to improve chronic pain management at home in elderly populations through a low-cost nonpharmacological intervention.

Cell-cell interactions via non-covalent click chemistry

Metabolic glycoengineering with unnatural sugars became a valuable tool for introducing recognition markers on the cell membranes via bioorthogonal chemistry. By using this strategy, we functionalized the surface of tumor and T cells using complementary artificial markers based on both β-cyclodextrins (β-CDs) and adamantyl trimers, respectively. Once tied on cell surfaces, the artificial markers induced cell-cell adhesion through non-covalent click chemistry. These unnatural interactions between A459 lung tumor cells and Jurkat T cells triggered the activation of natural killer (NK) cells thanks to the increased production of interleukin-2 (IL-2) in the vicinity of cancer cells, leading ultimately to their cytolysis. The ready-to-use surface markers designed in this study can be easily inserted on the membrane of a wide range of cells previously submitted to metabolic glycoengineering, thereby offering a simple way to investigate and manipulate intercellular interactions.

Fracture behavior of cancellous bone and cancellous bone-PMMA bone cement interface: An experimental study using an integrated methodology (wedge splitting test and Heaviside-based digital image correlation)

Minimally invasive methods, such as balloon kyphoplasty (BKP) and percutaneous sacroplasty (PS), which are now widely used for the surgical treatment of compression fractures, involve injection of a bolus of poly (methyl methacrylate) bone cement (hereafter, "bone cement") into the fractured tissue. Many of the common complications following these surgeries, such as cement leakage and adjacent-level fractures (in the case of BKP), have been postulated to be related to the quality of the cancellous bone-bone cement interface, which, in turn, is a function of its fracture resistance. It is common to use bovine cancellous bone or polyurethane foam (PF) as a substitute for human cancellous bone in biomechanical studies of these surgical methods. The literature is lacking in studies of determination of fracture properties of human cancellous bone-bone cement interface, bovine cancellous bone-bone cement interface, and PF-bone cement interface. In the present work, an integrated methodology (combination of wedge splitting test and Heaviside-based digital image correlation) was used to make these determinations as well as those for the bone cement, bones and the PF alone. The fracture properties determined were maximum fracture load (F_max), fracture toughness (K_c), and specific fracture energy (G_f). For example, G_f values for human cancellous bone and human cancellous bone-bone interface were 0.48±0.14 N/mm and 0.38±0.05 N/mm, respectively, whereas in the case of bovine cancellous bone and bovine cancellous bone-bone cement interface, they were 1.08±0.11 N/mm and 0.22±0.05 N/mm, respectively, and for PF (Grades 12.5 and 15.0) and PF-bone cement interface, they were 0.81±0.12 and 0.55±0.06 N/mm, respectively. The same trends were seen in the F_max and K_c results. These results suggest that it may not be justified to use either bovine cancellous bone or either of the PF grades as a substitute for human cadaveric cancellous bone in biomechanical studies of BKP, PS, and similar surgical methods.

Quantitative MRI to Characterize the Nucleus Pulposus Morphological and Biomechanical Variation According to Sagittal Bending Load and Radial Fissure, an ex vivo Ovine Specimen Proof-of-Concept Study

Background and context: Low back pain is a dramatic burden worldwide. Discography studies have shown that 39% of chronic low back pain patients suffer from discogenic pain due to a radial fissure of intervertebral disc. This can have major implications in clinical therapeutic choices. The use of discography is restricted because of its invasiveness and interest in it remains low as it represents a static condition of the disc morphology. Magnetic Resonance Imaging (MRI) appears to be less invasive but does not describe the biomechanical dynamic behavior of the fissure. Purpose: We aimed to seek a quantitative MRI protocol combined with ex vivo sagittal loading to analyze the morphological and biomechanical changes of the intervertebral disc structure and stress distribution. Study design: Proof of concept. Methods: We designed a proof-of-concept ovine study including 3 different 3.0 T-MRI sequences (T₂-weighted, T₁ and T₂ mapping). We analyzed 3 different mechanical states (neutral, flexion and extension) on a fresh ovine spine specimen to characterize an intervertebral disc before and after puncturing the anterior part of the annulus fibrosus. We used a mark tracking method to calculate the bending angles and the axial displacements of the discal structures. In parallel, we created a finite element model to calculate the variation of the axial stress and the maximal intensity shear stress, extrapolated from our experimental boundary conditions. Results: Thanks to an original combination of specific nuclear relaxation time quantifications (T₁, T₂) of the discal tissue, we characterized the nucleus movement/deformation into the fissure according to the synchronous mechanical load. This revealed a link between disc abnormality and spine segment range of motion capability. Our finite element model highlighted significant variations within the stress distribution between intact and damaged disc. Conclusion: Quantitative MRI appears to provide a new opportunity to characterize intra-discal structural morphology, lesions and stress changes under the influence of mechanical load. This preliminary work could have substantial implications for non-invasive disc exploration and could help to validate novel therapies for disc treatment.

Clinical, biological and bacteriological characteristics of osteoarticular infections in infants less than 12 months of age

Aim: This retrospective study's objective was to evaluate osteoarticular infection in infants less than 12 months of age, with a particular focus on biological features and bacteriological etiology. Material & methods: We retrospectively reviewed the medical records of every infant younger than 12 months old admitted in our institution for a suspected osteoarticular infection between January 1980 and December 2016. Results: Sixty-nine patients records were reviewed, including eight neonates, 16 infants from 1 to 5 months old, and 45 from 6 to 12 months old. Conclusion: Neonates and infants aged from 6 to 12 months old were more exposed to infections. Staphylococcus aureus remained the main pathogen in children <6 months, whereas Kingella kingae has become the most frequently isolated microorganism in infants aged from 6 to 12 months old.

Patient-Specific Finite Element Models of Posterior Pedicle Screw Fixation: Effect of Screw's Size and Geometry

Pedicle screw fixation is extensively performed to treat spine injuries or diseases and it is common for thoracolumbar fractures. Post-operative complications may arise from this surgery leading to back pain or revisions. Finite element (FE) models could be used to predict the outcomes of surgeries but should be verified when both simplified and realistic designs of screws are used. The aim of this study was to generate patient-specific Computed Tomography (CT)-based FE models of human vertebrae with two pedicle screws, verify the models, and use them to evaluate the effect of the screws' size and geometry on the mechanical properties of the screws-vertebra structure. FE models of the lumbar vertebra implanted with two pedicle screws were created from anonymized CT-scans of three patients. Compressive loads were applied to the head of the screws. The mesh size was optimized for realistic and simplified geometry of the screws with a mesh refinement study. Finally, the optimal mesh size was used to evaluate the sensitivity of the model to changes in screw's size (diameter and length) and geometry (realistic or simplified). For both simplified and realistic models, element sizes of 0.6 mm in the screw and 1.0 mm in the bone allowed to obtain relative differences of approximately 5% or lower. Changes in screw's length resulted in 4-10% differences in maximum deflection, 1-6% differences in peak stress in the screws, 10-22% differences in mean strain in the bone around the screw; changes in screw's diameter resulted in 28-36% differences in maximum deflection, 6-27% differences in peak stress in the screws, and 30-47% differences in mean strain in the bone around the screw. The maximum deflection predicted with realistic or simplified screws correlated very well (R ² = 0.99). The peak stress in screws with realistic or simplified design correlated well (R ² = 0.82) but simplified models underestimated the peak stress. In conclusion, the results showed that the diameter of the screw has a major role on the mechanics of the screw-vertebral structure for each patient. Simplified screws can be used to estimate the mechanical properties of the implanted vertebrae, but the systematic underestimation of the peak stress should be considered when interpreting the results from the FE analyses.

Osteoarticular infection in children

AIMS

We aimed to describe the epidemiological, biological, and bacteriological characteristics of osteoarticular infections (OAIs) caused by Kingella kingae.

METHODS

The medical charts of all children presenting with OAIs to our institution over a 13-year period (January 2007 to December 2019) were reviewed. Among these patients, we extracted those which presented an OAI caused by K. kingae and their epidemiological data, biological results, and bacteriological aetiologies were assessed.

RESULTS

K. kingae was the main reported microorganism in our paediatric population, being responsible for 48.7% of OAIs confirmed bacteriologically. K. kingae affects primarily children aged between six months and 48 months. The highest prevalence of OAI caused by K. kingae was between seven months and 24 months old. After the patients were 27 months old, its incidence decreased significantly. The incidence though of infection throughout the year showed no significant differences. Three-quarters of patients with an OAI caused by K. kingae were afebrile at hospital admission, 11% had elevated WBCs, and 61.2% had abnormal CRPs, whereas the ESR was increased in 75%, constituting the most significant predictor of an OAI. On MRI, we noted 53% of arthritis affecting mostly the knee and 31% of osteomyelitis located primarily in the foot.

CONCLUSION

K. kingae should be recognized currently as the primary pathogen causing OAI in children younger than 48 months old. Diagnosis of an OAI caused by K. kingae is not always obvious, since this infection may occur with a mild-to-moderate clinical and biological inflammatory response. Extensive use of nucleic acid amplification assays improved the detection of fastidious pathogens and has increased the observed incidence of OAI, especially in children aged between six months and 48 months. We propose the incorporation of polymerase chain reaction assays into modern diagnostic algorithms for OAIs to better identify the bacteriological aetiology of OAIs. Cite this article: Bone Joint J 2021;103-B(3):578-583.

Vertebral balloon kyphoplasty versus vertebral body stenting in non-osteoporotic vertebral compression fractures at the thoracolumbar junction: a comparative radiological study and finite element analysis (BONEXP study)

OBJECTIVE

To compare radiologically balloon kyphoplasty (BKP) and vertebral compression fracture (VCF) expansion and corroborate with a finite element (FE) analysis. The principle of BKP is to stabilize VCF by restoring vertebral body anatomy using bone expansion and cement filling. More recently, vertebral body stenting (VBS) has been developed to reduce the loss of vertebral height observed after balloon deflation.

METHODS

A retrospective, monocentric and continuous study of 60 non-osteoporotic fractures of the thoracolumbar junction treated by vertebral bone expansion was carried out over three years. The main endpoint was radiological correction of vertebral kyphosis (VK) at 3 months. The other studied parameters were vertebral height, index of Farcy, index of Beck, cement leakages and their location. A FE model was developed to analyze effects linked to the stent during cement injection, specifically throughout the risk of cement leakage evaluation.

RESULTS

After three months, average reduction of VK was 4.73° ± 4.8° after BKP, and 4.63° ± 2.7° after VBS. There was no difference between the two techniques, but cement leakage was significantly greater with BKP (41.7%) than with VBS (4.2%). FE analysis showed substantial changes of the cement flow orientation in the presence of a stent.

CONCLUSION

BKP and VBS offer comparable expansion with no added value of VBS in non-osteoporotic VCF reduction. VBS technique appears to prevent cement leakage due to its mesh architecture hindering the leaking process. In counterpart, such balloon expansion is likely to require higher pressure to deploy the stent. This could be an important parameter to take into account in young patients with high bone density.

Percutaneous treatment of tibial plateau fractures

In France, 11,294 proximal tibia fractures occurred in 2018 and 6880 surgical procedures were done to treat them. Most of these were tibial plateau fractures, although fractures can occur in the metaphysis only or in the intercondylar eminence. The proximal tibia's poor vascularization justifies sparing it by doing a percutaneous treatment, setting the stage for bone union. The treatment must be based on rigorous planning with 3D imaging to determine the type of fracture accurately. The goals of treatment are first to realign the lower limb and then to reduce the articular surface, while addressing any associated injuries. Percutaneous reduction is based on ligamentotaxis and the use of spatulas or balloons that spare the vascularization. Surgical navigation and arthroscopy are precious tools for verifying the reduction. There are several options for stabilization, ranging from using polymethylmethacrylate cement for a Schatzker III fracture to applying a cannulated screw or doing MIPPO (Minimal Invasive Percutaneous Plate Osteosynthesis) with an anatomical plate and adjustable locking screws placed under the depression in complex fractures. Percutaneous surgery is not about the size of the incisions; the focus is on sparing the metaphysis and its vascularization to ensure high-quality and long-lasting stability. It appears to yield better functional outcomes than open reduction and internal fixation, not only for Schatzker type I, II and III fractures, but also for complex fractures where open fixation is more damaging and the source of complications.

An innovative fixation technique by osteosuture in a young athletic female patient with coracoid process fracture: a case report

Coracoid process fractures are uncommon lesions but are frequently associated with an acromioclavicular dislocation. The aim of this article is to report our experience of an innovative fixation technique by osteosuture in a young athletic female patient presenting a displaced fracture of the coracoid process on the insertion footprint of coracoclavicular ligaments, with no breach of continuity of the lower coracoid cortex. She also had a roockwood type 3 acromioclavicular dislocation. After a deltopectoral approach, the fracture was reduced to the anatomical position and stabilized by a first lacing, using a non-absorbable large caliber thread passing under the mid part of the coracoid process between the 2 coracoclavicular ligaments. A second lacing passing under the coracoid process and through the trapezoid ligament, and a third one through the conoïd ligament. At 6 months, the fracture was consolidated and the constant score was 100/100. This innovative fixation provides good clinical and radiological results in the short and medium term.

Should we recommend occipital plate fixation using bicortical screws or inverted occipital hooks to optimize occipito-cervical junction fusion? A biomechanical study combining an experimental and analytical approach

BACKGROUND

Occipito-cervical fusion can be necessary in case of cranio-cervical junction instability. Proximal stabilisation is usually ensured by bi-cortical occipital screws implanted through one median or two lateral occipital plate(s). Bone thickness variability as well as the proximity of vasculo-nervous elements can induce substantial morbidity. The choice of site and implant type remains difficult for surgeons and is often empirically based. Given this challenge, implants with smaller pitch to increase bone interfacing are being developed, as is a surgical technique consisting in inverted occipital hook clamps, a potential alternative to plate/screws association. We present here a biomechanical comparison of the different occipito-cervical fusion devices.

METHODS

We have developed a 3D mark tracking technique to measure experimental mechanical data on implants and occipital bone. Biomechanical tests were performed to study the mechanical stiffness of the occipito-cervical instrumentation on human skulls. Four occipital implant systems were analysed: lateral plates+large pitch screws, lateral plates+hooks, lateral plates+small pitch screws and median plate+small pitch screws. Mechanical responses were analysed using 3D displacement field measurements from optical methods and compared with an analytical model.

FINDINGS

Paradoxical mechanical responses were observed among the four types of fixations. Lateral plates+small pitch screws appear to show the best accordance of displacement field between bone/implant/system interface providing higher stiffness and an average maximum moment around 50 N.m before fracture.

INTERPRETATION

Stability of occipito-cervical fixation depends not only on the site of screws implantation and occipital bone thickness but is also directly influenced by the type of occipital implant.

Comparison of conventional, burst and high-frequency spinal cord stimulation on pain relief in refractory failed back surgery syndrome patients: study protocol for a prospective randomized double-blinded cross-over trial (MULTIWAVE study)

Background

While the evolution of technology provides new opportunities to manage chronic refractory pain using different waveform modalities of spinal cord stimulation in failed back surgery syndrome (FBSS), there is no randomized controlled trial available to compare the efficacy of these different stimulations waveforms to date. MULTIWAVE is a prospective, randomized, double-blinded, crossover trial study designed to compare the clinical efficacy of tonic conventional stimulation (TCS), burst stimulation (BURST) and high-frequency stimulation (HF) in FBSS patients over a 15-month period in SCS implanted patients.

Methods/design

Twenty-eight patients will be recruited in the Poitiers University Hospital, in Niort and La Rochelle Hospitals in France. Eligible patients with post-operative low back and leg pain with an average visual analog scale (VAS) score ≥ 5 for low back pain are implanted and randomly assigned to one of the six arms (in a 1:1:1:1:1:1 ratio), where they receive a 3-month combination of TCS, BURST and HF including one treatment modality per month and varying the order of the modality received within the six possible combinations. Patients receiving intrathecal drug delivery, peripheral nerve stimulation and back resurgery related to the original back pain complaint and experimental therapies are excluded from this study. Patients included in the spinal cord stimulation group undergo trial stimulation, and they all receive a TCS treatment for 2 months, as the gold standard modality. Thereafter, patients are randomly assigned to one of the six arms for the total duration of 3-month crossover period. Then, patients choose their preferred stimulation modality (TCS, BURST, or HF) for the follow-up period of 12 months. Outcome assessments are performed at baseline (first implant), before randomization (2 months after baseline) and at 1, 2, 3, 6, 9 and 15 months post-randomization. Our primary outcome is the average global VAS of pain over 5-day pain diary period between baseline and after each period of stimulation. Additional outcomes include changes in leg and back pain intensity, functional disability, quality of life, psychological state, paraesthesia intensity perception, patient satisfaction and the number of adverse events.

Discussion

Recruitment began in February 2017 and will continue through 2019.

Trial registration

Clinicaltrials.gov NCT03014583. Registered on 9 January 2017.

Three-Dimensional Navigation (O-arm) for Minimally Invasive Shelf Acetabuloplasty

Hip dysplasia is an important cause of osteoarthritis in young adults. For these patients, conservative treatment is an interesting alternative to arthroplasty. The current literature suggests better clinical and functional outcomes when shelf acetabuloplasty is performed for a moderate joint pinch (<50%) associated with an important external coverage defect of the acetabular cup (<25°). Compared with open surgical procedures, minimally invasive surgical techniques or arthroscopy tend to reduce morbidity. To date, the major intraoperative difficulty remains the positioning of the graft. This Technical Note aims to outline a minimally invasive shelf acetabuloplasty, with optimization of the position of the autologous iliac crest bone graft using 3-dimensional navigation.

Medial closing-wedge distal femoral varus osteotomy: Symptoms and functional impact in cases of associated patellofemoral osteoarthritis. A two-year follow-up prospective pilot study

PURPOSE

To date, indications for distal femoral varus osteotomy (FVO) in cases of associated patellofemoral osteoarthritis (PFO) have yet to be clarified. The purpose of this prospective study is to assess the short-term symptoms, functional and radiological impact of a medial closing-wedge femoral varus osteotomy on the patellofemoral joint in patients with valgus deformities who are afflicted with lateral tibiofemoral osteoarthritis (LTFO) associated with PFO.

METHODS

Fourteen patients (15 knees) received a medial closing-wedge femoral varus osteotomy. The functional impact of an FVO on the patellofemoral joint was assessed based on the KOOS-PF (Knee Injury and Osteoarthritis Outcome Score-Patellofemoral Subscale), the Kujala score and the patellofemoral symptoms. Realignment of the patella was measured by the Merchant's patellofemoral congruence angle. The pre- and post-operative symptoms and functional scores were compiled prospectively and compared two years after the surgery.

RESULTS

The Kujala patellofemoral functional scores and the KOOS-PF showed considerable improvement with a differential of +37.5 points ± 20.4 and +42.7 points ± 19.3 (p < .01) respectively. The average Merchant's congruence angle went from 8.8° laterally to 3.6° medially, resulting in medialization of the patella, with a significant difference (p < .01). Based on the specific clinical analysis of the patellar joint, preoperative J-sign was identified in 26.7% of patients (n = 4) and was not found during postoperative examination (p = .1). Preoperative apprehension test was identified in 33.3% of patients (n = 5) against 13.3% (n = 2) after surgery (p = .39). Preoperative pain extension test was identified in 40% of patients (n = 6) against 20% during postoperative clinical analysis (p = .43).

DISCUSSION

Although the threshold of significance for patellofemoral symptoms was not reached, the medial closing-wedge femoral varus osteotomy induces a significant medialization of the patella (Merchant's congruence angle) and improves short-term functional results even with co-existing patellofemoral osteoarthritis. Due to the lack of specificity of the patellofemoral scores, patellofemoral osteoarthritis improvement is difficult to determine on its own, but does not represent a contraindication to FVO.

LEVEL OF EVIDENCE

III. Prospective clinical study.

How tibial tubercle torsion impacts patellar stability: A biomechanics study

INTRODUCTION

A new factor for patellofemoral instability-external torsion of the tibial tubercle-has recently been described. The primary aim of this biomechanics study was to analyze the consequences of internal torsion tibial tubercle osteotomy (TTO) on an experimentally unstable patella. We hypothesized that internal TTO can stabilize an experimental patellar instability.

MATERIALS AND METHODS

This in vitro study was conducted on six fresh anatomical specimens. The knees were flexed to 25°. The patella was destabilized by transecting the patellar retinaculae and the vastus medialis tendon and by applying continuous oblique traction on the quadriceps tendon. A 3D stereovision system was used to record patellar displacement and tilt and to determine whether patellar dislocation occurred. The measurements were done before the osteotomy then repeated on the same knee after a triangular internal torsion 30° TTO was completed, without medialization.

RESULTS

There was a significant difference in the patellar displacement and tilt before and after the osteotomy (p<0.05). Patellar dislocation, which was induced by traction on all the knees before osteotomy, did not occur after the osteotomy was performed.

DISCUSSION

Internal torsion of the tibial tubercle improves patellar stability, confirming our hypothesis. These findings confirm the stabilizing effect of placing the tibial tuberosity in internal torsion. Although a knee without instability factors is not the perfect model for patellar instability, our findings suggest that tibial tubercle torsion influences patellar stability. Internal TTO may be justified as a surgical treatment of patellofemoral instability.

Mismatch between rod bending and actual post-operative lordosis in lumbar arthrodesis with poly axial screws

BACKGROUND

The question of rod bending is essential during posterior lumbar fusion. The role of posterior instrumentation during spinal surgery remains to be defined. Despite an appropriate bending, a mismatch between rod lordosis and lumbar lordosis can occur. There is no study on the link between rod bending and lordosis. The purpose of this study was to evaluate parameters that explain the mismatch between lumbar lordosis and rod bending in lumbar surgery using polyaxial screws.

HYPOTHESIS

Radiological parameters explain the mismatch between the rod and the lordosis.

METHODS

This study was monocentric, retrospective, descriptive and analytic. All patients with posterior L3L5 fusion in an university-affiliated hospital in 2017 were included. Patients with past surgical history of anterior fusion on the levels L3L5, Coronal malalignment with a Cobb angle superior to 5°, the use of dynamic fixation systems were excluded. We measured on immediate post-operative standing profile x-ray: pelvic incidency, lumbar lordosis, lordosis of the instrumented segment, the distance between posterior wall and rod (EcarT) which reflect how homogeneously the screws are put in depth, the angle between screw and rod (thetaMA), the angle between screw and superior endplate (lambdaMA), the rod lordosis. Univariate and multivariate analysis were conducted to see if there was a link between all those parameters and the mismatch: vertebral lordosis-rod lordosis.

RESULTS

A total of 74 patients were included, mean age was 67. Eighteen were 360° fusion and 56 were postero-lateral fusions. There was no statistical association between demographic data, pelvic parameters, use of interbody devices and the mismatch. There was a statistical association between thetaMA, lambdaMA, EcarT and the mismatch (P<0,0001). A multivariate linear regression model was developed to create a new index: Mismatch analysis index.

CONCLUSION

Our study is the first on the link between rod bending and lumbar lordosis. Three radiologic factors are involved in not obtaining the planned lordosis in short lumbar fusion with polyaxial screws. Two factors depend on the way the surgeon positions screw parallel to the superior vertebral endplate(lambdaMA), and with a homogeneous depth (EcarT). And the last factor: ThetaMA is depending on the surgical technique (compression on screws, osteotomies, monoaxial screws, use of interbody devices).

LEVEL OF EVIDENCE

IV.

Comparative evaluation of minimally invasive 'tibial tuberoplasty' surgical technique versus conventional open surgery for Schatzker II-III tibial plateau fractures: design of a multicentre, randomised, controlled and blinded trial (TUBERIMPACT study)

INTRODUCTION

Fractures of the tibial plateau are in constant progression. They affect an elderly population suffering from a number of comorbidities, but also a young population increasingly practicing high-risk sports. The conventional open surgical technique used for tibial plateau fractures has several pitfalls: bone and skin devascularisation, increased risks of infection and functional rehabilitation difficulties. Since 2011, Poitiers University Hospital is offering to its patients a new minimally invasive technique for the reduction and stabilisation of tibial plateau fractures, named 'tibial tuberoplasty'. This technique involves expansion of the tibial plateau through inflation using a kyphoplasty balloon, filling of the fracture cavity with cement and percutaneous screw fixation. We designed a study to evaluate the quality of fracture reduction offered by percutaneous tuberoplasty versus conventional open surgery for tibial plateau fracture and its impact on clinical outcome.

METHODS AND ANALYSIS

This is a multicentre randomised controlled trial comparing two surgical techniques in the treatment of tibial plateau fractures. 140 patients with a Schatzker II or III tibial plateau fracture will be recruited in France. They will be randomised either in tibial tuberoplasty arm or in conventional surgery arm. The primary outcome is the postoperative radiological step-off reduction blindly measured on CT scan (within 48 hours post-op). Additional outcomes include other radiological endpoints, pain, functional abilities, quality of life assessment and health-economic endpoints. Outcomes assessment will be performed at baseline (before surgery), at day 0 (surgery), at 2, 21, 45 days, 3, 6, 12 and 24 months postsurgery.

ETHICS AND DISSEMINATION

This study has been approved by the ethics committee Ile-De-France X and will be conducted in accordance with current Good Clinical Practice (GCP) guidelines, Declaration of Helsinki and standard operating procedures. The results will be disseminated through presentation at scientific conferences and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

Clinicaltrial.gov:NCT03444779.

Impact of time to surgery in upper femoral fracture in orthogeriatrics

INTRODUCTION

Treatment of hip fracture in the elderly is a major public health issue. Orthogeriatric departments have been developed for these patients at high risk of complications. Time to surgery seems to be an important factor in the care pathway, but remains controversial.

OBJECTIVES

The aim of this study was to assess the impact of less than 24 hours' time to surgery on 1-year morbidity and mortality in patients managed in our orthogeriatric department.

HYPOTHESIS

The study hypothesis was that<24 hours' time to surgery decreases mortality in elderly patients with upper femoral fracture.

MATERIALS AND METHODS

A retrospective cohort study from September 2015 to July 2016 included patients aged 75 years and older, eligible for orthogeriatric management of upper femoral fracture. Patients with comorbidities were prioritized for admission and for access to the operating room. Time to surgery was defined as time between the arrival in A&E and transfer to the operating room. The primary endpoint was 1-year survival. Comorbidities were assessed on Charlson score. ROC curve analysis determined the optimal cut-off for time to surgery. Variables significantly associated with mortality were included in a Cox regression model to estimate the adjusted effect of time to surgery on mortality.

RESULTS

One hundred and eight patients were included; mean age, 87±6.2 years; 26 male (24.1%), 82 female (75.9%). One-year mortality was 24.1% (26/108). Mean time to surgery was 14.1±30.9hours. ROC curve analysis showed a rise in mortality after a cut-off of 22hours 37minutes (p<0.0001).

CONCLUSION

Within a dedicated orthogeriatric department, time to surgery is a significant factor in the management of hip fractures in the elderly. Patients should be prioritized for theater and ideally receive "early" surgery within 24hours of admission to A&E. The potential benefit of "ultra-early" surgery (time to surgery<6hours) requires robust assessment.

LEVEL OF EVIDENCE

IV, Retrospective cohort study.