Li ng Foo

Concentrated Bone Marrow Aspirate Improves Full-thickness Cartilage Repair Compared with Microfracture in the Equine Model

BACKGROUND The purpose of this study was to compare the outcomes of treatment with bone marrow aspirate concentrate, a simple, one-step, autogenous, and arthroscopically applicable method, with the outcomes of microfracture with regard to the repair of full-thickness cartilage defects in an equine model. METHODS Extensive (15-mm-diameter) full-thickness cartilage defects were created on the lateral trochlear ridge of the femur in twelve horses. Bone marrow was aspirated from the sternum and centrifuged to generate the bone marrow concentrate. The defects were treated with bone marrow concentrate and microfracture or with microfracture alone. Second-look arthroscopy was performed at three months, and the horses were killed at eight months. Repair was assessed with use of macroscopic and histological scoring systems as well as with quantitative magnetic resonance imaging. RESULTS No adverse reactions due to the microfracture or the bone marrow concentrate were observed. At eight months, macroscopic scores (mean and standard error of the mean, 9.4 + or - 1.2 compared with 4.4 + or - 1.2; p = 0.009) and histological scores (11.1 + or - 1.6 compared with 6.4 + or - 1.2; p = 0.02) indicated improvement in the repair tissue in the bone marrow concentrate group compared with that in the microfracture group. All scoring systems and magnetic resonance imaging data indicated that delivery of the bone marrow concentrate resulted in increased fill of the defects and improved integration of repair tissue into surrounding normal cartilage. In addition, there was greater type-II collagen content and improved orientation of the collagen as well as significantly more glycosaminoglycan in the bone marrow concentrate-treated defects than in the microfracture-treated defects. CONCLUSIONS Delivery of bone marrow concentrate can result in healing of acute full-thickness cartilage defects that is superior to that after microfracture alone in an equine model. CLINICAL RELEVANCE Delivery of bone marrow concentrate to cartilage defects has the clinical potential to improve cartilage healing, providing a simple, cost-effective, arthroscopically applicable, and clinically effective approach for cartilage repair.

Magnetic Resonance Imaging of Articular Cartilage Trauma, Degeneration, and Repair

The assessment of articular cartilage using magnetic resonance imaging has seen considerable advances in recent years. Cartilage morphologic characteristics can now be evaluated with a high degree of accuracy and reproducibility using dedicated pulse sequences, which are becoming standard at many institutions. These techniques detect clinically unsuspected traumatic cartilage lesions, allowing the physician to study their natural history with longitudinal evaluation and also to assess disease status in degenerative osteoarthritis. Magnetic resonance imaging also provides a more objective assessment of cartilage repair to augment the information obtained from more subjective clinical outcome instruments. Newly developed methods that provide detail at an ultrastructural level offer an important addition to cartilage evaluation, particularly in the detection of early alterations in the extracellular matrix. These methods have created an undeniably important role for magnetic resonance imaging in the reproducible, noninvasive, and objective evaluation and monitoring of cartilage. An overview of the advances, current techniques, and impact of magnetic resonance imaging in the setting of trauma, degenerative arthritides, and surgical treatment for cartilage injury is presented.

An autologous cartilage tissue implant NeoCart for treatment of grade III chondral injury to the distal femur: prospective clinical safety trial at 2 years.

Background The healing potential of damaged articular cartilage is limited. The NeoCart is a tissue-engineered collagen matrix seeded with autogenous chondrocytes designed for the repair of hyaline articular cartilage. Hypothesis The NeoCart implant is well tolerated in the human knee. Study Design Case series; Level of evidence, 4. Methods Eight patients (treatment group) with full-thickness cartilage injury were treated with the NeoCart and evaluated prospectively. Autogenous chondrocytes provided by arthroscopic biopsy were seeded into a 3-dimensional type I collagen scaffold. The seeded scaffold was subjected to a tissue-engineering protocol including treatment with a bioreactor. Implantation of the prepared cartilage tissue patch was performed via miniarthrotomy and secured with a collagen bioadhesive. Evaluations through 24 months postoperatively included the subjective International Knee Documentation Committee questionnaire, visual analog scale, range of motion, and cartilage-sensitive magnetic resonance imaging (MRI), including quantitative T2 mapping. Results Pain scores after NeoCart implantation were significantly lower than baseline at 12 and 24 months after the procedure (P < .05). Improved function and motion were also noted at 24 months. Six patients had 67% to 100% defect fill at 24 months with MRI evaluation. One patient had moderate (33%-66%) defect fill, and another patient had poor (less than 33%) defect fill. Partial stratification of T2 values was observed for 2 patients at 12 months and 4 patients at 24 months. No patients experienced arthrofibrosis or implant hypertrophy. Conclusion Pain was significantly reduced 12 and 24 months after NeoCart treatment. Trends toward improved function and motion were observed 24 months after implantation. The MRI indicated implant stability and peripheral integration, defect fill without overgrowth, progressive maturation, and more organized cartilage formation.

The Maturation of Synthetic Scaffolds for Osteochondral Donor Sites of the Knee An MRI and T2-Mapping Analysis

Objective: The purpose of this study was to analyze the morphological imaging characteristics and incorporation of TruFit bone graft substitute (BGS) plugs using cartilage-sensitive magnetic resonance imaging (MRI) and quantitative T2 mapping. Design: Twenty-six patients (mean age, 28.72 years; range, 11-56 years) underwent osteochondral autologous transplantation (OATS) for chondral defects with filling of the knee joint donor sites using Trufit BGS plugs. The mean follow-up interval between implantation and MRI analysis was 21.3 months (range, 6-39 months). During this period, 43 cartilage-sensitive and 25 quantitative T2-mapping MRI studies were performed. The donor sites were assessed for plug and interface morphology, displacement, hypertrophy, subchondral edema, presence of bony overgrowth, percentage fill, and degree of incorporation. T2 relaxation times were measured for the superficial and deep layers of the repair tissue. A linear regression and correlational analysis was performed with Bonferroni correction, and P < 0.05 was defined as significant. Results: Longitudinal analysis revealed favorable plug appearance at early follow-up (≤6 months), with 75% of plugs demonstrating flush morphology and 78% demonstrating near complete to complete fill. Plug appearance deteriorated at intermediate follow-up (~12 months), with only 26% of plugs demonstrating flush morphology and 52% with near complete or complete fill. Plug appearance substantially improved with longer follow-up (≥16 months), with 70% of plugs demonstrating flush morphology and 90% demonstrating near complete or complete fill. Interface resorption was common at ~12 months (P < 0.0001) and was associated with older age (P = 0.01) or a single-plug configuration (P = 0.04). T2 values for the repair cartilage approached that of normal cartilage with increasing duration after surgery (P < 0.004), more so for single- compared with multiple-plug configurations (P = 0.03). Conclusions: The Trufit BGS plug demonstrates a predictable pattern of postoperative maturation on MRI images that parallels its biological incorporation. An intermediate postoperative interval can be associated with unfavorable MRI findings. However, the plug appearance significantly improves with greater postoperative duration and has mean T2 relaxation times that approach those of normal articular cartilage.

Magnetic Resonance Imaging of Cartilage in the Athlete: Current Techniques and Spectrum of Disease

In the athletic population, reproducible imaging of cartilage damage is vital for treatment considerations. With appropriate pulse sequencing, magnetic resonance imaging has been shown to be an accurate noninvasive method for the evaluation of articular cartilage injuries and for evaluating postoperative changes following chondral repair. In addition, magnetic resonance imaging does not utilize ionizing radiation, has direct multiplanar capabilities, and allows high-resolution imaging of soft-tissue structures. The purposes of the present review are to update orthopaedic surgeons on the applications and techniques for magnetic resonance imaging of cartilage in the athletic population, to define the normal magnetic resonance imaging characteristics of articular cartilage, to illustrate the spectrum of articular cartilage lesions that are detectable with magnetic resonance imaging, and to review normal and abnormal magnetic resonance imaging findings following cartilage repair. After reviewing this article, the reader should (1) have a basic understanding of pulse sequences and terminology for cartilage-sensitive magnetic resonance imaging, including proton-density-weighted high-resolution fast-spin-echo sequences; (2) be able to identify normal and abnormal articular cartilage in the hip, knee, elbow, shoulder, and ankle; and (3) be able to identify normal and abnormal findings on postoperative magnetic resonance images after chondral repair techniques. An understanding of the structure of articular cartilage is crucial in order to understand the magnetic resonance imaging appearance of normal and abnormal cartilage morphology and is also the basis for the development of new imaging techniques. Articular cartilage is a viscoelastic material composed of chondrocytes (approximately 1%) embedded in an organized extracellular matrix composed primarily of water (65% to 80%), collagen, and proteoglycan. The predominant collagen is type II (95%), although smaller amounts of other collagen types (types IV, VI, IX, X, and XI) have been identified1. Collagen provides the structural framework and tensile strength of articular cartilage. Chondroitin and keratin sulfates …

What is the Role of Magnetic Resonance Imaging in the Evaluation of Total Hip Arthroplasty

MRI has been shown to be an extremely effective instrument in the management of painful hip arthroplasty. Its superior soft tissue contrast and direct multiplanar acquisition compared to computerized tomography (CT) and radiographs allows for reproducible visualization of periacetabular osteolysis, demonstrating compression of neurovascular bundles by extracapsular synovial deposits. In addition, MRI can often elucidate etiology of neuropathy in the perioperative period and is further helpful in evaluating the soft tissue envelope, including the attachment of the hip abductors, short external rotators and iliopsoas tendon. A further advantage of MRI over CT is its lack of ionizing radiation. Most importantly, MRI can disclose intracapsular synovial deposits that precede osteoclastic resorption of bone.

Using magnetic resonance angiography to measure abnormal synovial blood vessels in early inflammatory arthritis: a new imaging biomarker?

Objective. To ascertain whether magnetic resonance angiography (MRA) can reliably detect synovial neovascularization in subjects with early inflammatory arthritis. Methods. Subjects with 6 weeks to 6 months of clinical evidence of inflammatory hand arthritis had a radiograph, power Doppler ultrasound (PDU) scan, magnetic resonance imaging (MRI), and contrast enhanced MRA performed on the more symptomatic hand. Ultrasound examination of the wrist and 2nd–5th metacarpophalangeal (MCP) joints was scored for erosions, synovial thickening, and synovial blood flow. MRI were assessed using the OMERACT Rheumatoid Arthritis MRI Score (RAMRIS). MRA was used to assess the number of abnormal vessels in the 2nd–5th MCP and in the wrist. Results. Of 30 subjects, 66.7% showed abnormal vasculature on MRA in the MCP and/or wrist; mean number of abnormal vessels was 5.24 (range 0–22). Number of abnormal vessels on MRA was strongly correlated with degree of blood flow seen in the corresponding area on PDU (r = 0.79, p ≤ 0.0001). The number of abnormal vessels was highly correlated with MRI MCP synovitis scores (r = 0.69, p ≤ 0.0001), MRI wrist synovitis scores (r = 0.73, p ≤ 0.0001), and ultrasound synovitis scores (r = 0.68, p ≤ 0.0001). Conclusion. In this cross-sectional pilot study, MRA identified abnormal vessels in patients with early inflammatory arthritis. This is the first report of MRA visualizing abnormal vessels in this patient population. If the degree of neovascularization in early inflammatory arthritis predicts disease course, MRA evidence of abnormal vessels could be a new imaging biomarker.

Magnetic Resonance Imaging in the Diagnosis and Management of Hip Pain After Total Hip Arthroplasty

Evaluation of pain following total hip arthroplasty (THA) can be challenging in the absence of radiographic pathology. This study aimed to examine the diagnostic utility of magnetic resonance imaging (MRI) in the evaluation of enigmatic hip pain following THA. We reviewed a series of patients who were evaluated with MRI after presenting with enigmatic hip pain following THA. MRI was able to demonstrate pathology in the periprosthetic tissues in all hips with minimal artifact. Patients underwent a range of conservative and operative interventions depending on the underlying pathology. If used discriminately in situations where pathology cannot be detected by conventional methods, MRI is a highly effective modality that can aid in the diagnosis of a wide range of disorders thereby allowing the clinician to determine the most appropriate intervention.

Traumatic Lateral Plantar Artery Pseudoaneurysm and the Use of Time-Resolved MR Angiography

Vascular injury resulting in pseudoaneurysm formation in the plantar aspect of the foot is an uncommon injury after trauma. Such injuries are more often reported in the lateral plantar artery rather than the medial plantar artery, most likely because of its more superficial location. Traditional modalities in diagnosis have included ultrasound and digital subtraction angiography. We present a case of traumatic pseudoaneurysm of the lateral plantar artery following a foot laceration. Diagnosis was made by the use of high-resolution, time-resolved contrast-enhanced 3D magnetic resonance angiography, also referred to as “TRICKS” (time-resolved imaging of contrast kinetics). This technique provided high spatial resolution for the arterial anatomy as well as temporal resolution which allowed better delineation of the hemodynamic characteristics of the pseudoaneurysm.

Anterior glenoid perforation with suture anchor causing subscapularis irritation and pain.

Background:Suture anchors for labral repair have been associated with complications including suprascapular notch encroachment and osteolysis.Case Description:We present a case of suture anchor penetration of the anterior glenoid neck leading to pain secondary to subscapularis muscle irritation in a 14-year-old boy. The patient had labral repair and subsequent anterior shoulder pain which resolved after anchor removal.Literature Review:Chondrolysis of the glenohumeral joint has been described following labral repair with knotless anchors. There have also been cases of injury to the suprascapular nerve following labral repair. However, we are not aware of any reports describing suture anchor penetration of the anterior glenoid neck leading to pain secondary to subscapularis muscle irritation.Purposes and Clinical Relevance:Labral repair has become a common and routine procedure, but complications can occur. We report a new complication related to osseous penetration of the anterior glenoid neck of the scapula by a suture anchor. We identified the complication using magnetic resonance imaging, an important part in reproducible, noninvasive, and objective assessment of the postoperative shoulder. We also present the technique for anchor removal used to resolve the patient’s anterior shoulder pain.