Patellar articular overlap is better associated with patellar alignment during weight-bearing than traditional measures of patellar height.

Background: A consequence of a high riding patella is reduced osseous stability and malalignment of the patella (i.e., lateral patellar tilt and displacement).

Managing Patients With Unlabeled Passive Implants on MR Systems Operating Below 1.5 T.

The standard of care for managing a patient with an implant is to identify the item and to assess the relative safety of scanning the patient. Because the 1.5 T MR system is the most prevalent scanner in the world and 3 T is the highest field strength in widespread use, implants typically have "MR Conditional" (i.

Xenograft bone-patellar tendon-bone ACL reconstruction: a case series at 20-year follow-up as proof of principle.

Purpose: ACL reconstruction has a significant failure rate. To address the need for inexpensive strong tissue, a treatment process to "humanize" porcine tissue was developed and tested in primates and humans. This report describes the long-term outcomes from the first human clinical trial using a porcine xenograft ACL reconstruction device.

Variations of magnetic resonance imaging findings in asymptomatic elbows.

Background: Magnetic resonance imaging (MRI) findings in asymptomatic patients have been described for hips, knees, ankles, shoulders, and intervertebral disks. No such description exists for the elbow.

Methods: MRI scans of 189 asymptomatic elbows divided into 3 groups by age (group 1, 20-39 years; group 2, 40-59 years; and group 3, ≥60 years) were evaluated for abnormalities within 13 anatomic structures using a novel classification system.

Magnetic Resonance Imaging for Patellofemoral Chondromalacia: Is There a Role for T2 Mapping?

Background: Patellofemoral pain is common, and treatment is guided by the presence and grade of chondromalacia.

Purpose: To evaluate and compare the sensitivity and specificity in detecting and grading chondral abnormalities of the patella between proton density fat suppression (PDFS) and T2 mapping magnetic resonance imaging (MRI).

Study Design: Cohort study; Level of evidence, 2.

Identifying Hidden Zones of the Far Posterior Cartilage of the Femoral Condyles Not Visible During Knee Arthroscopy.

Objective: The purpose of this study was to compare standard knee arthroscopic and MRI findings and measurements for visualization of the femoral condyle articular cartilage. The hypothesis was that certain posterior cartilage defects identified with MRI may not be accessible with routine arthroscopy.

Materials And Methods: Six cadaveric knees were examined by routine arthroscopy through standard inferomedial and inferolateral portals.

Osteochondral grafting for failed knee osteochondritis dissecans repairs.

Background: Revision of failed surgical treatments of osteochondritis dissecans (OCD) lesions remains a challenge without an obvious solution. The aim of this study was to evaluate seven consecutive patients undergoing osteochondral grafting of a failed OCD repair.

Methods: The mean time from surgery to the latest evaluation was 7.

Clinical and magnetic resonance imaging findings associated with Little League elbow.

Background: Valgus overload in the skeletally immature elbow can lead to medial epicondyle apophysitis, or Little League elbow. The skeletal manifestations have been well described through radiographic studies. The involvement of surrounding structures, including the ulnar collateral ligament, remains unclear.

A quantitative approach to sequence and image weighting.

Weighting is the term most frequently used to describe magnetic resonance pulse sequences and the concept most commonly used to relate image contrast to differences in magnetic resonance tissue properties. It is generally used in a qualitative sense with the single tissue property thought to be most responsible for the contrast used to describe the weighting of the image as a whole. This article describes a quantitative approach for understanding the weighting of sequences and images, using filters and partial derivatives of signal with respect to logarithms of tissue property values.

Bone marrow edema is the most specific finding for rheumatoid arthritis (RA) on noncontrast magnetic resonance imaging of the hands and wrists: a comparison of patients with RA and healthy controls.

Objective: To evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) in detecting erosions, bone edema, and synovitis in the metacarpophalangeal and wrist joints for rheumatoid arthritis (RA).

Methods: MRI scans of bilateral hands and wrists of 40 healthy subjects and 40 RA patients were performed using 0.2 T extremity-MRI and read blindly using a modified RA MRI (RAMRIS) system (no contrast injection, imaging in 1 plane only).

Complexities of MRI and false positive findings.

MRI is a robust technology that allows for superior contrast of muscles, tissues, and bones within the body, which enables visualization of soft tissue pathology that cannot be seen with CT or plain film radiography. In order to appreciate the subtle (and sometimes not so subtle) intricacies of MRI, one must have a basic knowledge of the MRI physics involved to acquire an image, which leads to better recognition and a clearer understanding of some of the more important artifacts seen with MRI, including incomplete fat suppression, chemical shift, magnetic susceptibility, magic angle, partial volume, wraparound, and motion artifact. There are, however, many complexities and pitfalls in imaging the rheumatoid wrist.

Technical considerations and potential advantages of musculoskeletal imaging at 3.0 Tesla.

High field magnetic resonance imaging at 3.0 T is rapidly gaining clinical acceptance as the preferred platform for magnetic resonance (MR) imaging. This is spurred in part because advances in the manufacture of magnet technology have brought the cost of 3.

Repair site integrity after arthroscopic transosseous-equivalent suture-bridge rotator cuff repair.

Background: Successful healing after arthroscopic rotator cuff repair remains a challenge. Earlier studies have shown a relatively high rate of failure. New surgical techniques may improve healing potential.

Ironman triathletes: MRI assessment of the shoulder.

Objective: The objective of this paper was to demonstrate the prevalence of shoulder magnetic resonance imaging (MRI) abnormalities, including abnormal bone marrow signal at the acromioclavicular (AC) joint in symptomatic and asymptomatic Ironman Triathletes.

Materials And Methods: The shoulders of 23 Ironman Triathletes, seven asymptomatic (group I) and 16 symptomatic (group II), were studied by MRI. A separate, non-triathlete group was evaluated specifically for AC joint marrow signal abnormalities to compare with the Ironman Triathletes.

Meniscal sizing based on gender, height, and weight.

Purpose: Successful meniscus transplantation may depend on accurate sizing. Meniscal sizing is currently determined by measuring a combination of bony landmarks and soft-tissue insertion points through images obtained radiographically or by magnetic resonance imaging (MRI). The literature widely reports inaccuracy in sizing resulting from radiographic errors in magnification, erroneous identification of bony landmarks, and difficulty in differentiating between the soft-tissue and bone interface.

Open-label, pilot protocol of patients with rheumatoid arthritis who switch to infliximab after an incomplete response to etanercept: the opposite study.

Objective: To incorporate a new trial design to examine clinical response, cytokine expression and joint imaging in patients with rheumatoid arthritis (RA) switching from etanercept to infliximab treatment.

Methods: A randomised, open-label, clinical trial of 28 patients with an inadequate response to etanercept was conducted. Eligible patients received background methotrexate and were randomised 1:1 to discontinue etanercept and receive infliximab 3 mg/kg at weeks 0, 2, 6, 14 and 22, or to continue etanercept 25 mg twice weekly.

3.0 Tesla imaging of the musculoskeletal system.

High-field MRI at 3.0T is rapidly gaining clinical acceptance and experiencing more widespread use. The superiority of high-field imaging has clearly been demonstrated for neurological imaging.

Low-field musculoskeletal MRI.

Since it was first introduced in the field of medical imaging in the early 1980s, MRI has become essential for the diagnosis and treatment of musculoskeletal conditions. Most imaging in the United States is performed on high-field (>1.0T), whole-body scanners.

Magnetic resonance imaging is more sensitive than radiographs in detecting change in size of erosions in rheumatoid arthritis.

Objective: To evaluate the technological performance of magnetic resonance imaging (MRI) with respect to projection radiography by determining the incidence of changes in the size of individual bone lesions in inflammatory arthritis, using serial high-resolution in-office MRI over short time intervals (8 months average followup), and by comparing the sensitivity of 3-view projection radiography with in-office MRI for detecting changes in size and number of individual erosions.

Methods: MR examinations of the wrists and second and third metacarpophalangeal joints were performed using a portable in-office MR system in a total of 405 patients with inflammatory arthritis, from one rheumatologist's practice, who were undergoing aggressive disease modifying antirheumatic drug therapy. Of the patients, 156 were imaged at least twice, allowing evaluation of 246 followup examinations (mean followup interval of 8 months over a 2-year period).

Low field MRI: a review of the literature and our experience in upper extremity imaging.

Since its introduction to medical imaging in the early 1980s, MRI has become essential in diagnosis and treatment of musculoskeletal conditions. Most imaging in the United States is performed on high-field whole-body scanners (>1.0 T).

MR procedures: biologic effects, safety, and patient care.

The technology used for magnetic resonance (MR) procedures has evolved continuously during the past 20 years, yielding MR systems with stronger static magnetic fields, faster and stronger gradient magnetic fields, and more powerful radiofrequency transmission coils. Most reported cases of MR-related injuries and the few fatalities that have occurred have apparently been the result of failure to follow safety guidelines or of use of inappropriate or outdated information related to the safety aspects of biomedical implants and devices. To prevent accidents in the MR environment, therefore, it is necessary to revise information on biologic effects and safety according to changes that have occurred in MR technology and with regard to current guidelines for biomedical implants and devices.