Clinical outcomes after inferior vena cava resection for malignant disease. A single center experience of 51 vena cava resections

BACKGROUND AND OBJECTIVE

For tumors involving inferior vena cava (IVC), surgery with complete resection remains the first line treatment. Management of IVC after resection, either ligation without reconstruction or primary reconstruction, is debated. Our study aimed to evaluate type of venous reconstruction, anticoagulation management and morbidity.

METHODS

A French single center database of patients who underwent partial or total circumferencial resection of the IVC for malignant disease was analyzed. Inclusion criteria were any oncologic procedure for a retroperitoneal neoplasm requiring concomitant resection of the IVC with or without venous reconstruction with prosthesis. Exclusion criteria were surgery before year 2000. Data were descriptive and reverse Kaplan Meier was used for follow-up calculation. The endpoints were the rate of prosthetic reconstruction, the use of anticoagulation and the post-operative outcomes.

RESULTS

Fifty - one patients were included with a median duration of follow-up of 54.8 months. The majority of patients were men (56.9%). Median age of the population was 44.1 years. Most of the patients underwent surgery for primary testicular cancer and for sarcoma. Complete IVC resections were performed in 46 (90,2%) patients, 32 having a concomitant prosthetic replacement. Eight patients underwent aortic resection in the same operative time. Postoperative morbidity was 33.3%. Post-operative anticoagulation was done in 24 patients. At 1 month, four patients developed thrombosis in the prosthesis.

CONCLUSIONS

IVC resections are feasible and safe. Venous reconstruction and postoperative management were planned according to the preoperative imaging and intraoperative findings. We propose a decision-tree for peri-operative management and anticoagulation.

A multifunctional ionic liquid coating on 3D-Printed prostheses: Combating infection, promoting osseointegration

Periprosthetic infection and mechanical loosening are two leading causes of implant failure in orthopedic surgery that have devastating consequences for patients both physically and financially. Hence, advanced prostheses to simultaneously prevent periprosthetic infection and promote osseointegration are highly desired to achieve long-term success in orthopedics. In this study, we proposed a multifunctional three-dimensional printed porous titanium alloy prosthesis coated with imidazolium ionic liquid. The imidazolium ionic liquid coating exhibited excellent bacterial recruitment property and near-infrared (NIR) triggered photothermal bactericidal activity, enabling the prosthesis to effectively trap bacteria in its vicinity and kill them remotely via tissue-penetrating NIR irradiation. In vivo anti-infection and osseointegration investigations in infected animal models confirmed that our antibacterial prosthesis could provide long-term and sustainable prevention against periprosthetic infection, while promoting osseointegration simultaneously. It is expected to accelerate the development of next-generation prostheses and improve patient outcomes after prosthesis implantation.

Mid-term clinical radiological results of the constrained condylar knee prosthesis in total knee revision

INTRODUCTION

The aim of the present study is to analyze the clinical-radiological outcomes of patients undergoing knee prosthesis revision surgery using constrained condylar prosthesis (LCCK; Zimmer-Biomet).

MATERIAL AND METHODS

Retrospective study of 89 patients operated on between the years 2008 and 2020 with a minimum of 2 years of follow-up. Clinical outcomes were evaluated using the WOMAC Index score and KOOS scales. Radiological results (radiolucent lines, osteolysis, and cortical hypertrophy) were evaluated by two independent observers. Implant survival was analyzed using the Kaplan-Meier method.

RESULTS

At the end of follow-up, a mean WOMAC Index score of 78.67 and KOOS score of 68.8 were obtained. Radiolucent lines (both non-progressive and progressive) were detected in 83.3% of the patients in the sample. Areas of osteolysis > 5 mm around the components were present in 6.75%. Cortical hypertrophy was seen around the femoral stem in 20.3% of cases, around the tibial stem in 20.3% and around both components in 6.76%. No statistically significant relationship was found between the presence of radiolucent lines, osteolysis or cortical hypertrophy with functional results. Implant survival was 88.1% at 13 years.

CONCLUSION

The present study shows high survival of LCCK prosthesis in revision surgery. The progressive radiolucencies, were associated with worst clinical outcome.

Comparison of inter-joint coordination strategies during activities of daily living with prosthetic and anatomical limbs

While healthy individuals have redundant degrees of freedom of the joints, they coordinate their multi-joint movements such that the redundancy is effectively reduced. Achieving high inter-joint coordination may be difficult for upper limb prosthesis users due to the lack of proprioceptive feedback and limited motion of the terminal device. This study compared inter-joint coordination between prosthesis users and individuals without limb loss during different upper limb activities of daily living (ADLs). Nine unilateral prosthesis users (five males) and nine age- and sex-matched controls without limb loss completed three unilateral and three bilateral ADLs. Principal component analysis was applied to the three-dimensional motion trajectories of the trunk and arms to identify coordinative patterns. For each ADL, we quantified the cumulative variance accounted for (VAF) of the first five principal components (pcs), which was the lowest number of pcs that could achieve 90% VAF in control limb movements across all ADLs (5 ≤ n ≤ 9). The VAF was lower for movements involving a prosthesis compared to those completed by controls across all ADLs (p < 0.001). The pc waveforms were similar between movements involving a prosthesis and movements completed by control participants for pc1 (r > 0.78, p < 0.001). The magnitude of the relationship for pc2 and pc3 differed between ADLs, with the strongest correlation for symmetric bilateral ADLs (0.67 ≤ r ≤ 0.97, p < 0.001). Collectively, this study demonstrates that activities of daily living were completed with distinct coordination strategies in prosthesis users compared to individuals without limb loss. Future work should explore how device features, such as the availability of sensory feedback or motorized wrist joints influence multi-joint coordination.

Computational analysis of prosthesis production via topology optimization

This work investigates the use of Topology Optimization (TO) to support the design of femur prosthesis to obtain more efficient solutions from the point of view of material distribution and internal forces. Computational tests were performed by the Interior-Point OPTimizer (IPOPT) method, seeking to explore the elastic mechanical characteristics of three real scenarios of daily loads on the femur. Numerical examples are presented to verify the novelty of the proposed method. The results obtained indicate that it is possible to reduce the volume of material up to 30% of the customize human femoral prosthesis, respecting all the boundary conditions.

Updates in Surgical Oncology

New knowledge and data can influence the treatment options of dogs and cats affected by neoplasms. Partial limb amputation with the use of a prosthesis is possible in dogs. Newer studies attempt to define better and understand the complications and limb function associated with this approach. Limb sparing is an alternative to amputation, and three-dimensional printing allows the manufacturing of personalized endoprostheses. Finally, the recommended approach for the excision of cutaneous mast cell tumors (MCTs) is with proportional margins. In dogs, grade shifting might have occurred when removing a recurrent MCT or soft tissue sarcoma.

Indication and surgical approach for reconstruction with endoprosthesis in bone-associated soft tissue sarcomas: Appropriate case management is vital

It is important for surgeons performing sarcoma surgery to know that bone resection and tumor prosthesis applications in soft tissue sarcomas (STS) have unique features in terms of indication, surgical approach and follow-up, in terms of the management of these cases. Some STS are associated with bone and major neurovascular structures. Bone-associated STS are generally relatively large and relatively deep-seated. Additionally, the tendency for metastasis is high. In some cases, the decision about which structures to resect is difficult. These cases are often accompanied by poor oncological and surgical outcomes. Management of cases should be done by a multidisciplinary team in advanced centers specialized in this field. The surgical team must have sufficient knowledge and experience in the field of limb-sparing surgery. Preoperative evaluation and especially good planning of bone and soft tissue reconstruction are vital.

Ultra-high-resolution CT of the temporal bone: The end of stapes prosthesis dimensional error and correlation with patient symptoms

PURPOSE

To describe the reliability of ultra-high-resolution computed tomography (UHR-CT) in the measurement of titanium stapes prostheses using manufacturer data as a reference.

MATERIALS AND METHODS

This retrospective study included patients treated by stapedectomy with titanium prostheses who underwent UHR-CT between January 2020 and October 2023. Images were acquired using an ultra-high-resolution mode (slice thickness: 0.25 mm; matrix, 1024 × 1024). Two radiologists independently evaluated the length, diameter, and intra-vestibular protrusion of the prosthesis. Post-operative air-bone gaps (ABGs) were recorded.

RESULTS

Fourteen patients were enrolled (mean age, 44.3 ± 13.8 [SD] years, 9 females), resulting in 16 temporal bone UHR-CTs. The exact length was obtained in 81.3 % (n = 13/16) and underestimated by 0.1 to 0.3 mm in the remaining 18.7 % (n = 3/16) CT scans for both readers (mean misestimation: -0.02 ± 0.06 [SD] mm, overall underestimation of 0.43 %). The exact diameter was reported in 75 % (n = 12/16) and 87.5 % (n = 14/16) of the CT scans for readers 1 and 2, respectively, and was off by 0.1 mm in all discrepancies (mean misestimation: 0.01 ± 0.04 [SD] mm, overall overestimation of 2.43 %). Intravestibular prosthesis protrusion was of 0.5 ± 0.43 [SD] mm (range: 0-1) and 0.49 ± 0.44 [SD] mm (range: 0-1.1) for readers 1 and 2, respectively, and did not correlate with ABGs (r = 0.25 and 0.22; P = 0.39 and 0.47 for readers 1 and 2, respectively). Intra and interobserver agreements were excellent.

CONCLUSION

UHR-CT provides 99.6 % and 97.6 % accuracy for prosthesis length and diameter measurements, respectively.

De Quervain tendinitis after total trapeziometacarpal joint arthroplasty: Biomechanical evaluation of tendon excursion in the first extensor tendon compartment

De Quervain's tenosynovitis is the most common complication after total trapeziometacarpal joint replacement. Etiology is unclear. Implantation of a ball-in-socket implant changes the biomechanics of the normal trapeziometacarpal saddle joint and increases its range of motion. The present study demonstrates that this procedure also significantly increases excursion of the abductor pollicis longus and extensor pollicis brevis tendons during thumb flexion-extension, and not during thumb abduction-adduction. Increased tendon gliding under the retinaculum of the first extensor tendon compartment could predispose to the development frictional tenosynovitis and play a role in the development of de Quervain's syndrome after total trapeziometacarpal joint replacement. LEVEL OF EVIDENCE: Not applicable (laboratory study).

Surface replacing arthroplasty of a post-traumatic stiff and deviated proximal interphalangeal joint in an adolescent

This case report describes the 4-year outcomes of proximal interphalangeal joint arthroplasty in a 14-year-old girl with a stiff joint after trauma. At follow-up, active range of motion was 35°, she was pain-free and satisfied with the outcome. Implant arthroplasty seems to be a valuable option for young patients with persistent post-traumatic stiff and deviated PIP joints to-at least temporarily-increase quality of life.

The influence of pontic distribution on the marginal and internal gaps of CAD/CAM five-unit anterior zirconia framework

Background/purpose

Nowadays, zirconia-based framework has been used for longspan or full-arch fixed dental prostheses (FDPs). This study aimed to evaluate the effect of pontic distribution on marginal and internal gaps of five-unit anterior zirconiabased DPs.

Materials and methods

Right maxillary central incisor and second premolar were selected as terminal abutments and three different edentulous conditions with one nonterminal abutment were simulated. Marginal and internal gaps in each zirconia-based samples(n = 10) were examined by computer-aided replica technique. Five regions, including marginal gaps at mesial or distal finishing line, internal gaps at the mesial or distal axial wall, and occlusal surface, were statistically analyzed (α = .05).

Results

Most of marginal gaps and internal gaps at axial wall were clinically acceptable, but larger at occlusal surface. For the three experimental groups, clinically accepted percentage with qualified gaps were less than 30%.There were statistical differences at axial wall over pontic side and marginal gaps over non-pontic side between groups (P<0.05). For sum of gaps of all abutments in each group, statistical differences were found at marginal and axial wall (P < 0.05). As for those on terminal and non-terminal abutments, statistical differences were found on second premolar (P < 0.05).

Conclusion

Except for occlusal surface, the overall marginal gaps and internal gaps at axial wall of five-unit anterior zirconia-based FDPs with different pontic distribution were clinically acceptable. However, the percentage with qualified gaps were low (<30%). Greater gaps were noted when adjacent pontic existed. Different pontic size and distribution with curvature had an influence on the gaps.

Three Sliding Probes Placed on Forelimb Skin for Proprioceptive Feedback Differentially yet Complementarily Contribute to Hand Gesture Detection and Object-Size Discrimination

The purpose was to assess the effectiveness of three sliding tactile probes placed on the forelimb skin to provide proprioceptive feedback for the detection of hand gestures and discrimination of object size. Tactile contactors representing the first three fingers were driven along the proximodistal axis by linear servo motors. Twenty healthy subjects were involved in the gesture detection test, with 10 of them also participating in the object-size discrimination task. Motors were controlled by computer in the first four sessions of the gesture detection experiment, while the fifth session utilized a sensorized glove. Both the volar and dorsal sides of the forearm were examined. In the object-size discrimination experiment, the method was exclusively assessed on the volar surface under four distinct feedback conditions, including all fingers and each finger separately. The psychophysical data were further analyzed using a structural equation model (SEM) to evaluate the specific contributions of each individual contactor. Subjects consistently outperformed the chance level in detecting gestures. Performance improved up to the third session, with better results obtained on the volar side. The performances were similar in the fourth and fifth sessions. The just noticeable difference for achieving a 75% discrimination accuracy was found to be 2.90 mm of movement on the skin. SEM analysis indicated that the contactor for the index finger had the lowest importance in gesture detection, while it played a more significant role in object-size discrimination. However, all fingers were found to be significant predictors of subjects' responses in both experiments, except for the thumb, which was deemed insignificant in object-size discrimination. The study highlights the importance of considering the partial contribution of each degree of freedom in a sensory feedback system, especially concerning the task, when designing such systems.

Advances in Implant Technologies for Spine Surgery

Spine implants are becoming increasingly diversified. Taking inspiration from other industries, three-dimensional modeling of the spinal column has helped meet the custom needs of individual patients as both en bloc replacements and pedicle screw designs. Intraoperative tailoring of devices, a common need in the operating room, has led to expandable versions of cages and interbody spacers.

Three-dimensional printed pure-titanium implantation for chest wall reconstruction involving the sternum and ribs: a novel approach

Chest wall reconstruction is challenging due to the complex shape and large defect size. The three-dimensional printing technology enables the fabrication of customized implants, and 3D-printed pure-titanium could provide superior mechanical properties to conventional materials. The aim of this study was to evaluate long-term outcomes of patients undergoing chest wall reconstruction with a 3D-printed pure-titanium implant. Between August 2018 and May 2021, 5 patients underwent surgery due to sternal metastasis (n = 3), postoperative sternal wound infection (n = 1) and deformity (n = 1). The customized implant was designed and constructed based on the size and shape of the chest wall defect measured on computed tomography. All patients demonstrated uneventful recovery without complications during the hospital course. During the median follow-up of 20 months, 1 patient underwent revision surgery due to implant breakage, and 1 removed the implant due to trauma-related chest wall infection. One patient died from cancer progression, while 3 patients are alive without any implant-related complications. Chest wall reconstruction using a 3D-printed pure-titanium implant could be a novel alternative for patients with various conditions affecting the sternum and ribs.

Modular intercalary prosthetic reconstruction for malignant and metastatic tumours of the proximal femur

To illustrate the surgical technique and explore clinical outcomes of the reconstruction for the malignant and metastatic bone tumour of proximal femur with metallic modular intercalary prosthesis. Sixteen patients who underwent modular intercalary prosthetic reconstruction after tumour resection were included from April 2012 and October 2020. Prosthesis and screws parameters, resected bone length and residual bone length, clinical outcomes and survivorship were analyzed. All patients were followed up for an average of 19 months (range 1-74). In our series, 12 patients died of the progression of the primary disease at the final follow-up. The cumulative survivorship since the treatment of proximal femoral metastasis was 78.6% (11 patients) at 6 months and 38.5% (5 patients) at 1 year. The mean MSTS score was 22.25 ± 4.55 among all patients. There were no cases of loosening or breakage of the prostheses, plates or screws, despite the various measurements of prostheses and residual bones. Modular intercalary prosthetic reconstruction was an effective method for malignant tumour of the proximal femur, including the advantages of providing early pain relief, quickly restoring postoperative function, required a short operation time, and preserving the adjacent joints.

The influence of prosthetic suspension on gait and cortical modulations is persons with a transfemoral amputation: socket-suspended versus bone-anchored prosthesis

BACKGROUND

Persons with a transfemoral amputation (TFA) often experience difficulties in daily-life ambulation, including an asymmetrical and less stable gait pattern and a greater cognitive demand of walking. However, it remains unclear whether this is effected by the prosthetic suspension, as eliminating the non-rigid prosthetic connection may influence stability and cortical activity during walking. Spatiotemporal and stability-related gait parameters, as well as cortical activity during walking, were evaluated between highly active individuals (MFC-level K3-4) with a TFA and able-bodied (AB) persons, and between persons with a bone-anchored prosthesis (BAP) and those with a socket-suspended prosthesis (SSP).

METHODS

18 AB persons and 20 persons with a unilateral TFA (10 BAP-users, 10 SSP-users) walked on a treadmill at their preferred speed. Spatiotemporal and margin of stability parameters were extracted from three-dimensional movement recordings. In addition, 126-channel electroencephalogram (EEG) was recorded. Brain-related activity from several cortical areas was isolated using independent component analysis. Source-level data were divided into gait cycles and subjected to time-frequency analysis to determine gait-cycle dependent modulations of cortical activity.

RESULTS

Persons with TFA walked with smaller and wider steps and with greater variability in mediolateral foot placement than AB subjects; no significant differences were found between BAP- and SSP-users. The EEG analysis yielded four cortical clusters in frontal, central (both hemispheres), and parietal areas. No statistically significant between-group differences were found in the mean power over the entire gait cycle. The event-related spectral perturbation maps revealed differences in power modulations (theta, alpha, and beta bands) between TFA and AB groups, and between BAP- and SSP-users, with largest differences observed around heel strike of either leg.

CONCLUSIONS

The anticipated differences in gait parameters in persons with TFA were confirmed, however no significant effect of the fixed suspension of a BAP was found. The preliminary EEG findings may indicate more active monitoring and control of stability in persons with TFA, which appeared to be timed differently in SSP than in BAP-users. Future studies may focus on walking tasks that challenge stability to further investigate differences related to prosthetic suspension.

Can99mTc-MDP-SPECT/CT Differentiate Loosening and Infection After Hip and Knee Replacements?

Background

Prosthetic loosening and infection are still common complications after joint replacement. Over the past few years, single-photon emission computed tomography-computed tomography (SPECT/CT) was widely used and showed unique value based on the combination of anatomic and metabolic information of foci. However, its performance in differentiating between prosthetic loosening and periprosthetic infection after joint replacement is still the focus of clinicians and deserves further investigation.

Purpose

This retrospective study was aimed to determine whether bone scintigraphy combined with SPECT/CT still can differentiate prosthetic infection from loosening in patients after joint replacement. The differential efficacy in hip and knee prosthesis was also analyzed. Blood biomarkers for the diagnosis of periprosthetic infection were also evaluated.

Patients and methods

Data sets of 74 prosthetic joints (including knees and hips), with suspected prosthetic loosening or infection between 2015 and 2021, were evaluated. Besides the results of nuclear imaging, X-ray images and serum biomarker were also recorded. Telephone follow-up and revision surgery after SPECT/CT were used as a gold standard. The sensitivity and accuracy of different imaging modalities were calculated by Chi-square test. The diagnostic efficacy of imaging methods and serum biomarkers were then analyzed by the area under curve (receiver operating characteristic curves, ROC) in SPSS 26.

Results

In all, 47 joints (14 knees and 33 hips) were confirmed as aseptic loosening, while 25 joints (18 knees and 7 hips) were confirmed as infection. The sensitivity and accuracy of SPECT combined with SPECT/CT imaging were the highest (92.86% and 87.84%, respectively). The differential efficacy of bone scintigraphy combined with SPECT/CT imaging was also better than any other single imaging modality. In the analysis of involved prosthesis, prosthetic loosening occurred more in hip prosthesis and knee prosthesis was easily infected (P < 0.05). Finally, the sensitivity of ESR and CRP were 80% and 84%, respectively.

Conclusions

Bone scintigraphy with hybrid SPECT/CT remains encouraging in differentiating prosthetic infection from loosening after joint replacement. The diagnostic efficacy of differentiation in hip prosthesis was better than knee. Serum biomarkers cannot be used alone to differentiate prosthetic infection from loosening.

User- and Speed-Independent Slope Estimation for Lower-Extremity Wearable Robots

Wearable robots can help users traverse unstructured slopes by providing mode-specific hip, knee, and ankle joint assistance. However, generalizing the same assistance pattern across different slopes is not optimal. Control strategies that scale assistance based on slope are expected to improve the feel of the device and improve outcome measures such as decreasing metabolic cost. Prior numerical methods for slope estimation struggled to estimate slopes at variable walking speeds or were limited to a single estimation per gait cycle. This study overcomes these limitations by developing machine-learning methods that yield continuous, user- and speed-independent slope estimators for a variety of wearable robot applications using an able-bodied wearable sensor dataset. In a leave-one-subject-out cross-validation (N = 9), four-phase XGBoost regression models were trained on static-slope (fixed-slope) data and evaluated on a novel subject's static-slope and dynamic-slope (variable-slope) data. Using all available sensors, we achieved an average error of 0.88° and 1.73° mean absolute error (MAE) on static and dynamic slopes, respectively. Ankle prosthesis, knee-ankle prosthesis, and hip exoskeleton sensor suites yielded average errors under 2° MAE on static and dynamic slopes, except for the ankle prosthesis and hip exoskeleton cases on dynamic slopes which yielded an average error of 2.2° and 3.2° MAE, respectively. We found that the thigh inertial measurement unit contributed the most to a reduction in average error. Our findings suggest that reliable slope estimators can be trained using only static-slope data regardless of the type of lower-extremity wearable robot.

A systematic investigation of sensorimotor mechanisms with intelligent prostheses in patients with ankle amputation while walking

It is thought that creating sensorimotor feedback in people with ankle joint amputation can affect motor biomechanics during gait, but there is little evidence or previous research. This study e aim ed to investigate the sensorimotor mechanism of smart prostheses in with ankle amputations while walking. Search in Google Scholar, Scopus, PubMed and Medline databases between April 2017 and February 2023, in addition to a detailed review in specialized clinical and engineering databases, 29 articles were selected based on the inclusion and exclusion criteria. Trials that mainly include; Proprioception, walking process in movement disorders, ankle amputation were included. Qualitative assessments of selected trials using PEDro' scale was used. The review of studies showed that the use of pressure sensors, neural stimulation through encoded algorithms can provide continuous tactile and positional information of the artificial leg in the direction of neural stimulation throughout the entire walking cycle. These findings indicate that restoration of intraneuronal sensory feedback leads to functional and cognitive benefits. With these definitions, different companies and research centers are trying to improve the mechanics of walking, however, movement strategies are unknown despite little research in creating sense and movement in the use of smart prostheses.

Validation of Proprietary and Novel Step-counting Algorithms for Individuals Ambulating With a Lower Limb Prosthesis

OBJECTIVE

To compare the accuracy and reliability of 10 different accelerometer-based step-counting algorithms for individuals with lower limb loss, accounting for different clinical characteristics and real-world activities.

DESIGN

Cross-sectional study.

SETTING

General community setting (ie, institutional research laboratory and community free-living).

PARTICIPANTS

Forty-eight individuals with a lower limb amputation (N=48) wore an ActiGraph (AG) wGT3x-BT accelerometer proximal to the foot of their prosthetic limb during labeled indoor/outdoor activities and community free-living.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Intraclass correlation coefficient (ICC), absolute and root mean square error (RMSE), and Bland Altman plots were used to compare true (manual) step counts to estimated step counts from the proprietary AG Default algorithm and low frequency extension filter, as well as from 8 novel algorithms based on continuous wavelet transforms, fast Fourier transforms (FFTs), and peak detection.

RESULTS

All algorithms had excellent agreement with manual step counts (ICC>0.9). The AG Default and FFT algorithms had the highest overall error (RMSE=17.81 and 19.91 steps, respectively), widest limits of agreement, and highest error during outdoor and ramp ambulation. The AG Default algorithm also had among the highest error during indoor ambulation and stairs, while a FFT algorithm had the highest error during stationary tasks. Peak detection algorithms, especially those using pre-set parameters with a trial-specific component, had among the lowest error across all activities (RMSE=4.07-8.99 steps).

CONCLUSIONS

Because of its simplicity and accuracy across activities and clinical characteristics, we recommend the peak detection algorithm with set parameters to count steps using a prosthetic-worn AG among individuals with lower limb loss for clinical and research applications.

Optimized reamer geometry for controlled reaming of the proximal femur

Preparation of the femoral proximal medullary cavity by reaming is essential for intramedullary nail osteosynthesis and hip revision arthroplasty. The use of reamers sometimes exerts high torsional forces on the bone. Design and direction of rotation of the reamer are potential influencing factors. The aim of this biomechanical study is to evaluate the best combination of a right- or left-cutting reamer with a clockwise- or counterclockwise-rotating insert in terms of preparation and safety. Right- and left-cutting reamers with conical design were each introduced into five synthetic femurs in both clockwise and counterclockwise rotation with constant feed force. A specially constructed test system was used for this series of tests, with which the respective intramedullary channel were reamed step by step. This was then used to determine the required torque. In addition, the feed rate measurement was analyzed using a modified digital caliper. The feed rates of the reamers with rotation in the same direction as the cutting direction were significantly increased compared to rotation in the opposite cutting direction (CCRLC vs. CCRRC 76.8 ± 9.0 mm/s vs. 25.2 ± 8.3 mm/s and CRRC vs. CRLC 54.3 ± 12.3 mm/s vs. 19.3 ± 0.6 mm/s; p < 0.01). In contrast, the mean torque during the reaming process was identical in all four groups. When preparing the proximal femoral medullary cavity, especially in cases with fragile bone structure, the available reamers should be introduced in opposite rotation to the cutting direction to achieve a more controllable feed of the reamer. Left-cutting reamers represent an alternative, using them in the usual clockwise-rotating technique to reduce the risk of complications during reaming.

Thumb basal joint arthritis in 2023

Thumb carpometacarpal or basal joint arthritis is the second most common location for osteoarthritis in the hand. It mainly affects women over 50years of age. Basal joint arthritis causes pain, loss of strength during pinch grips, and eventually stiffness and progressive deformity of the thumb column. Conservative treatment must be implemented first. It aims to spare the joint by using standardized methods. It must be initiated as soon as pain starts, not once the deformity has settled in. There is broad agreement that surgery is indicated when pain relief is not achieved after at least 6months of conservative treatment. The available surgical techniques can be classified as joint-sparing (extra-articular) and joint-sacrificing (intra-articular). The former consists of trapeziometacarpal stabilizing ligament reconstruction, subtraction osteotomy of the first metacarpal and thumb carpometacarpal denervation. The latter consists of trapeziometacarpal fusion, trapeziectomy (and its variants) and implant arthroplasty. Except in very specific cases, trapeziectomy and trapeziometacarpal implant arthroplasty with a total joint prosthesis or an interposition implant are the two main surgical techniques for treating basal joint arthritis. After reviewing the pathophysiology and the diagnosis of thumb basal joint arthritis, we will provide an overview of the available treatment options, with emphasis on the accepted surgical strategies in 2023. LEVEL OF EVIDENCE: III.

Does trapezium remodeling correlate with cup shape?

We investigated whether trapezium bone reaction was different following implantation of a trapeziometacarpal total joint replacement with a hemispheric or a conical cup. Fifty-three Keri Medical Touch implants with hemispheric cup and 53 with conical cup were prospectively followed up radiographically. We compared radiographs taken immediately and one year after surgery for cup subsidence, tilt, heterotopic ossification and loosening. Cup subsidence of at least 1 mm was detected in 4% of cases for both cup types. Additive bone reaction around the cup of more than 1 mm was present in 62% of conical cups and 47% of hemispheric cups. These were minor and there were no large ossifications with risk of impingement. Minor radiolucency was seen superficially at the implant-bone interface of 13% of the hemispheric cups and 9% of the conical cups. None of these bone reactions differed significantly according to cup design.

Transfemoral limb loss modestly increases the metabolic cost of optimal control simulations of walking

Background

In transtibial limb loss, computer simulations suggest that the maintenance of muscle strength between pre- and post-limb loss can maintain the pre-limb loss metabolic cost. These results are consistent with comparable costs found experimentally in select cases of high functioning military service members with transtibial limb loss. It is unlikely that similar results would be found with transfemoral limb loss, although the theoretical limits are not known. Here we performed optimal control simulations of walking with and without an above-knee prosthesis to determine if transfemoral limb loss per se increases the metabolic cost of walking.

Methods

OpenSim Moco was used to generate optimal control simulations of walking in 15 virtual "subjects" that minimized the weighted sum of (i) deviations from average able-bodied gait mechanics and (ii) the gross metabolic cost of walking, pre-limb loss in models with two intact biological limbs, and post-limb loss with one of the limbs replaced by a prosthetic knee and foot. No other changes were made to the model. Metabolic cost was compared between pre- and post-limb loss simulations in paired t-tests.

Results

Metabolic cost post-limb loss increased by 0.7-9.3% (p < 0.01) depending on whether cost was scaled by total body mass or biological body mass and on whether the prosthetic knee was passive or non-passive.

Conclusions

Given that the post-limb loss model had numerous features that predisposed it to low metabolic cost, these results suggest transfemoral limb loss per se increases the metabolic cost of walking. However, the large differences above able-bodied peers of ∼20-45% in most gait analysis experiments may be avoidable, even when minimizing deviations from able-bodied gait mechanics. Portions of this text were previously published as part of a preprint (https://www.biorxiv.org/content/10.1101/2023.06.26.546515v2.full.pdf).

Surgical aortic valve replacement etiologies, hemodynamics, and outcomes in 1346 patients from the Malaysian heart centre

BACKGROUND

This study examined the characteristics and outcomes of surgical aortic valve replacement (SAVR) both isolated and in combination with other cardiac surgery in Malaysia from 2015 to 2021.

METHODS

This was a retrospective study of 1346 patients analyzed on the basis of medical records, echocardiograms and surgical reports. The overall sample was both considered as a whole and divided into aortic stenosis (AS)/aortic regurgitation (AR)-predominant and similar-severity subgroups.

RESULTS

The most common diagnosis was severe AS (34.6%), with the 3 most common etiologies being bicuspid valve degeneration (45.3%), trileaflet valve degeneration (36.3%) and rheumatic valve disease (12.2%). The second most common diagnosis was severe AR (25.5%), with the most common etiologies being root dilatation (21.0%), infective endocarditis (IE) (16.6%) and fused prolapse (12.2%). Rheumatic valve disease was the most common mixed disease. A total of 54.5% had AS-predominant pathology (3 most common etiologies: bicuspid valve degeneration valve, degenerative trileaflet valve and rheumatic valve disease), 36.9% had AR-predominant pathology (top etiologies: root dilatation, rheumatic valve disease and IE), and 8.6% had similar severity of AS and AR. Overall, 62.9% of patients had trileaflet valve morphology, 33.3% bicuspid, 0.6% unicuspid and 0.3% quadricuspid. For AS, the majority were high-gradient severe AS (49.9%), followed by normal-flow low-gradient (LG) severe AS (10.0%), paradoxical low-flow (LF)-LG severe AS (6.4%) and classical LF-LG severe AS (6.1%). The overall in-hospital and total 1-year mortality rates were 6.4% and 14.8%, respectively. Pure severe AS had the highest mortality. For AS-predominant pathology, the etiology with the highest mortality was trileaflet valve degeneration; for AR-predominant pathology, it was dissection. The overall survival probability at 5 years was 79.5% in all patients, 75.7% in the AS-predominant subgroup, 83.3% in the AR-predominant subgroup, and 87.3% in the similar-severity subgroup.

CONCLUSIONS

The 3 most common causes of AS- predominant patients undergoing SAVR is bicuspid valve degeneration, degenerative trileaflet valve and rheumatic and for AR-predominant is root dilatation, rheumatic and IE. Rheumatic valve disease is an important etiology in our SAVR patients especially in mixed aortic valve disease. Study registration IJNREC/562/2022.