Key safety considerations for MRI examination of patients with an orthopaedic implant.

Introduction: Magnetic resonance imaging (MRI) provides superior soft tissue contrast, multiplanar capabilities, and avoids ionizing radiation, making it valuable for evaluating orthopedic conditions. Despite persistent concerns regarding MRI safety with orthopedic instrumentation, this imaging modality is particularly well-suited to evaluate pain and weakness following hardware placement. This review examines the evidence regarding safety and efficacy of MRI in patients with orthopedic implants.

Noise-robust foreground segmentation of multispectral imaging calibration volume in the presence of metallic implants for spectral range estimation in phantom and in-vivo data.

Purpose: Multispectral Imaging (MSI) methods can use a calibration scan to estimate an off-resonance field-map to determine the spectral range required to cover off-resonant signal in the presence of metallic implants of various shape and composition. Background signal noise can corrupt the field-map estimation in this calibration process. Previous work on foreground segmentation used a cumulative distribution function (CDF) to remove signal extrema, which can remove regions of true off-resonance signal from the calibration analysis.

Arthrofibrosis Severity in Knees With Failed Total Knee Arthroplasties Differs With Magnetic Resonance Imaging Synovial Classification.

Background: Treatment of stiffness following total knee arthroplasty (TKA) is complicated by a lack of a specific diagnosis for arthrofibrosis. Magnetic resonance imaging (MRI) provides a noninvasive means to generate and evaluate clinically diagnostic images of deep structures within the knee. The purpose of this study was to assess how the severity and location of arthrofibrosis observed on MRI relate to MRI synovial classifications and range of motion in primary TKA patients undergoing revision surgery.

Utility of Zero Echo Time MRI for the Diagnosis and Characterization of Ankle Fractures.

Zero echo time (ZTE) imaging is a relatively new magnetic resonance (MR) pulse sequence that provides bone-soft tissue contrast similar to that of computed tomography (CT). We sought to (1) determine the accuracy of ZTE MRI for the diagnosis of common ankle fractures and (2) investigate whether ZTE imaging sequences are equivalent to the gold standard of CT for the characterization of fracture fragments. We conducted a prospective case series of 54 patients with acute ankle trauma, in whom ZTE MRI was performed, followed by surgical reduction.

MRI-based radiomic analysis of soft tissue reactions near total hip arthroplasty.

This study applied radiomics to MRI data for automated classification of soft tissue abnormalities near total hip arthroplasty (THA). A total of 126 subjects with 1.5 T MRI of symptomatic THA were included in the analysis.

Baseline-to-loaded changes in regional tibial cartilage thickness, T1ρ and T2: Utilization of an MRI compatible loading device.

The objective of the study was to evaluate tibial cartilage thickness (TCT), T1ρ and T2 values within both loaded and baseline configurations in a cadaveric knee model using a 3D bone based tibial coordinate system. Ten intact cadaveric knees were mounted into an magnetic resonance imaging (MRI) compatible loading device. Morphologic and quantitative MRI (qMRI) images were acquired with the knee in a baseline configuration and after application of 50% body weight.

Fully automated determination of robotic pedicle screw accuracy and precision utilizing computer vision algorithms.

Historically, pedicle screw accuracy measurements have relied on CT and expert visual assessment of the position of pedicle screws relative to preoperative plans. Proper pedicle screw placement is necessary to avoid complications, cost and morbidity of revision procedures. The aim of this study was to determine accuracy and precision of pedicle screw insertion via a novel computer vision algorithm using preoperative and postoperative computed tomography (CT) scans.

Association of Total Hip Arthroplasty Flexural Rigidity With Magnetic Resonance Imaging and Histological Findings.

Background: Modular connections in total hip arthroplasty (THA) offer surgical advantages, but can contribute to implant fretting and corrosion due to micromotion at the head-stem interface. Previous studies implicated lower flexural rigidity as a key contributing factor to THA corrosion and fretting, but none associated flexural rigidity with direct histological evaluation or magnetic resonance imaging (MRI) outcomes. The purpose of this study was to determine how implant flexural rigidity is associated with MRI imaging metrics and histopathological outcomes in patients who have a failed THA.

Multiparametric MRI of Knees in Collegiate Basketball Players: Associations With Morphological Abnormalities and Functional Deficits.

Background: Rates of cartilage degeneration in asymptomatic elite basketball players are significantly higher compared with the general population due to excessive loads on the knee. Compositional quantitative magnetic resonance imaging (qMRI) techniques can identify local biochemical changes of macromolecules observed in cartilage degeneration.

Purpose/hypothesis: The purpose of this study was to utilize multiparametric qMRI to (1) quantify how T and T relaxation times differ based on the presence of anatomic abnormalities and (2) correlate T and T with self-reported functional deficits.

Chondral Injury Associated With ACL Injury: Assessing Progressive Chondral Degeneration With Morphologic and Quantitative MRI Techniques.

Background: Anterior cruciate ligament (ACL) injuries are associated with a risk of post-traumatic osteoarthritis due to chondral damage. Magnetic resonance imaging (MRI) techniques provide excellent visualization and assessment of cartilage and can detect subtle and early chondral damage. This is often preceding clinical and radiographic post-traumatic osteoarthritis.

The role of advanced metal artifact reduction MRI in the diagnosis of periprosthetic joint infection.

Identification and diagnosis of periprosthetic joint infection (PJI) are challenging, requiring a multi-disciplinary approach involving clinical evaluation, laboratory tests, and imaging studies. MRI is advantageous to alternative imaging techniques due to superior soft tissue contrast and absence of ionizing radiation. However, the presence of metallic implants can cause signal loss and artifacts.

Novel Osteochondral Biotemplate Improves Long-term Cartilage Repair Compared With Microfracture in an Ovine Model.

Background: Current cartilage repair therapies do not re-create the complex mechanical interface between cartilage and bone, which is critical for long-term repair durability. New biomaterial designs that include hard tissue-soft tissue interface structures offer promise to improve clinical outcomes.

Purpose/hypothesis: The purpose of this study was to evaluate the efficacy and safety of a naturally derived osteochondral biotemplate with a novel contiguous hard tissue-soft tissue interface in an ovine model as a regenerative solution for articular cartilage defects.

MRI Advancements in Musculoskeletal Clinical and Research Practice.

Over the past decades, MRI has become increasingly important for diagnosing and longitudinally monitoring musculoskeletal disorders, with ongoing hardware and software improvements aiming to optimize image quality and speed. However, surging demand for musculoskeletal MRI and increased interest to provide more personalized care will necessitate a stronger emphasis on efficiency and specificity. Ongoing hardware developments include more powerful gradients, improvements in wide-bore magnet designs to maintain field homogeneity, and high-channel phased-array coils.

A multimodal assessment of cementless tibial baseplate fixation using radiography, radiostereometric analysis, and magnetic resonance imaging.

Fixation in cementless total knee arthroplasty is provided by osseous integration. Radiography, radiostereometric analysis (RSA), and magnetic resonance imaging (MRI) were used simultaneously to investigate fixation. Relationships between RSA-measured implant micromotions and MRI-evaluated osseous integration at the component-bone interface were assessed in 10 patients up to 6 months postoperation.

Exuberant Rice Body Formation Associated with Adverse Local Tissue Reaction After Hip Resurfacing Arthroplasty: A Case Report and Review of the Literature.

Case: A 65-year-old man with osteoarthritis of the hip developed a soft-tissue mass of the inferior gluteal region 3 years after metal-on-metal resurfacing hip arthroplasty. Clinical and imaging findings suggested an adverse local tissue reaction. Intraoperatively, nearly 1 liter of intra-articular fibrinous loose bodies (rice bodies) was removed, and histology showed features of an adaptive immune response.

Correlation of Arthroscopic Grading and Optical Coherence Tomography as Markers of Early Repair and Predictors of Later Healing Evident on MRI and Histomorphometric Assessment of Cartilage Defects Implanted with Chondrocytes Overexpressing IGF-I.

Objective: Injury of articular cartilage is common, and due to the poor intrinsic capabilities of chondrocytes, it can precipitate joint degradation and osteoarthritis (OA). Implantation of autologous chondrocytes into cartilaginous defects has been used to bolster repair. Accurate assessment of the quality of repair tissue remains challenging.

Significantly Worse Fixation of Cemented Patellar Components on Multiacquisition Variable-Resonance Image Combination Magnetic Resonance Imaging Compared to Femoral and Tibial Components: A Cause for Concern?

Background: The etiology of anterior knee pain after total knee arthroplasty (TKA) remains unclear. Few studies have examined patellar fixation quality. The purpose of the present study was to evaluate the patellar cement-bone interface after TKA on magnetic resonance imaging (MRI) and to correlate the patella fixation grade with the incidence of anterior knee pain.

Bone Marrow Edema Injury Patterns in the Pediatric Knee: An MRI Study.

Background: Symptomatic pediatric patients referred for magnetic resonance imaging (MRI) commonly present with traumatic bone marrow edema (BME) patterns.

Purpose: We sought to associate discrete MRI patterns of BME with specific injury mechanisms in pediatric knee injuries to classify injury patterns by anatomical location of the BME. We aimed to group these into 6 patterns: patellar dislocation, extensor mechanism overload, hyperextension, single compartment impaction, ligament avulsion/translation, and direct contusion.

Diffusion-weighted MRI of total hip arthroplasty for classification of synovial reactions: A pilot study.

Background: Conventional quantitative diffusion-weighted imaging (DWI) is sensitive to changes in tissue microstructure, but its application to evaluating patients with orthopaedic hardware has generally been limited due to metallic susceptibility artifacts. The apparent diffusion coefficient (ADC) and T-values from a multi-spectral imaging (MSI) DWI combined with 2D multi-spectral imaging with a 2D periodically rotated overlapping parallel lines with enhanced reconstruction (2D-MSI PROPELLER DWI) based sequence and a MAVRIC based T mapping sequence, respectively, may mitigate the artifact and provide additional quantitative information on synovial reactions in individuals with total hip arthroplasty (THA). The aim of this pilot study is to utilize a 2D-MSI PROPELLER DWI and a MAVRIC-based T mapping to evaluate ADC and T-values of synovial reactions in patients with THA.

MAVRIC based T2 mapping assessment of infrapatellar fat pad scarring in patients with total knee arthroplasty.

The infrapatellar fat pad (IPFP) has been implicated as a source of postoperative knee pain. Imaging the IPFP is challenging in patients with total knee arthroplasty (TKA) due to metallic susceptibility artifact. Multi-Acquisition Variable-Resonance Image Combination (MAVRIC)-based T2 Mapping has been developed to mitigate this artifact and can generate quantitative T2 data.

Multiacquisition Variable-Resonance Image Combination Magnetic Resonance Imaging to Study Detailed Bone Apposition and Fixation of Cementless Knee System Compared to Cemented Total Knee Replacements.

Background: The ability to utilize magnetic resonance imaging (MRI) to assess bony fixation may allow a better understanding of implant design and longevity. A new cementless total knee arthroplasty (TKA) was introduced, and we hypothesized that this cementless system would show similar fixation compared to a cemented system as assessed by multispectral MRI.

Methods: Multiacquisition variable-resonance image combination selective MRI was performed in 20 patients implanted with a cementless TKA.