Carl S. Winalski

Evaluation of cartilage injuries and repair.

Articular cartilage injuries ( Fig. 1 ) are common findings during arthroscopy 1 and diagnostic imaging of the joints 2,3. While there are many techniques for the treatment of cartilage injuries, not enough is known about which lesions need treatment or about the proper treatment modality for a particular lesion. More objective data regarding cartilage injuries and more accurate methods to evaluate the operative outcomes are required, especially since new procedures are becoming increasingly expensive. There are many published reports on the outcomes of total joint replacement based on clinical scores and radiographic evaluations. However, it has been quite difficult to interpret the reported results of the repair of focal cartilage defects as there is no universally accepted system to describe the lesions, the repair tissue, or the clinical symptoms for this category of patients. More studies on clinical articular cartilage resurfacing will appear in the future, making it important to develop common evaluation measurement tools and standards. The International Cartilage Repair Society (ICRS) was founded in 1997 and has been interested in developing a standardization system for the evaluation of cartilage injury and repair 4,5. A working group of the ICRS was established with the aim of developing a common, easy system for clinical and arthroscopic evaluation ( Table I ). Shortly thereafter, the Articular Cartilage Imaging Committee of the ICRS was created to assess the existing clinical imaging techniques, to recommend specific magnetic resonance imaging techniques for the assessment of articular cartilage 6, and to develop a standardized magnetic resonance imaging evaluation system for native and repaired cartilage ( Table I ). A state-of-the-art system for clinical cartilage evaluation and imaging assessment is presented below. Fig. 1: A cartilage lesion on a femoral condyle, extending deep down to bone. Note that some calcified …

Contrast manipulation and artifact assessment of 2D and 3D RARE sequences

The extent of contrast manipulation and the assessment of characteristic artifacts in imaging studies of brain and knee as performed with novel variants of the Rapid Acquisition Relaxation Enhanced (RARE) sequence are reported. Methods of ordering the phase encoding within one or two echo trains are proposed for manipulating T2 contrast. Options for minimizing artifacts associated with the various schemes are discussed. The extent of T1 contrast manipulation in RARE sequences is explored by varying repetition rates in a signal averaging scheme and by applying inversion pulses prior to data acquisition. The results demonstrate that RARE sequences can be utilized for obtaining good quality images with a range of tissue contrast options similar to those associated with slower spin-echo methods. They also suggest that RARE applications need not be confined to highlighting long T2 fluid spaces, an application already well documented.

MRI of Articular Cartilage: Revisiting Current Status and Future Directions

OBJECTIVE The purpose of this article is to review the current understanding of the MRI appearance of articular cartilage and its relationship to the microscopic and macroscopic structure of articular cartilage, the optimal pulse sequences to be used in imaging, the appearance of both degenerative and traumatic chondral lesions, the appearance of the most common cartilage repair procedures, and future directions and developments in cartilage imaging. CONCLUSION Articular cartilage plays an essential role in the function of the diarthrodial joints of the body but is frequently the target of degeneration or traumatic injury. The recent development of several surgical procedures that hold the promise of forming repair tissue that is hyaline or hyalinelike cartilage has increased the need for accurate, noninvasive assessment of both native articular cartilage and postoperative repair tissue. MRI is the optimal noninvasive method for assessment of articular cartilage.

Magnetic resonance imaging of articular cartilage of the knee: comparison between fat-suppressed three-dimensional SPGR imaging, fat-suppressed FSE imaging, and fat-suppressed three-dimensional DEFT imaging, and correlation with arthroscopy.

To compare signal‐to‐noise ratios (S/N) and contrast‐to‐noise ratios (C/N) in various MR sequences, including fat‐suppressed three‐dimensional spoiled gradient‐echo (SPGR) imaging, fat‐suppressed fast spin echo (FSE) imaging, and fat‐suppressed three‐dimensional driven equilibrium Fourier transform (DEFT) imaging, and to determine the diagnostic accuracy of these imaging sequences for detecting cartilage lesions in osteoarthritic knees, as compared with arthroscopy.

Magnetic Resonance Imaging of Articular Cartilage

Magnetic resonance imaging is the optimal modality for assessing articular cartilage because of superior soft tissue contrast, direct visualization of articular cartilage, and multiplanar capability. Despite these advantages, there has been disagreement as to the efficacy of magnetic resonance imaging of articular cartilage. The reason for this controversy is multifactorial but in part is attributable to the lack of the use of optimized pulse sequences for articular cartilage. The current authors will review the current state of the art of magnetic resonance imaging of articular cartilage and cartilage repair procedures, discuss future new directions in imaging strategies and methods being developed to measure cartilage thickness and volume measurements, and propose a magnetic resonance imaging protocol to evaluate cartilage that is achievable on most magnetic resonance scanners, vendor independent, practical (time and cost efficient), and accepted and used by a majority of musculoskeletal radiologists.

Outcomes After a Single-Stage Procedure for Cell-Based Cartilage Repair A Prospective Clinical Safety Trial With 2-year Follow-up

Background: There are currently several approaches being pursued to treat focal defects of articular cartilage, each having specific advantages or challenges. A single-stage procedure that uses autologous cartilage fragments, Cartilage Autograft Implantation System (CAIS), is being evaluated in patients and may offer a clinically effective option. Purpose: To establish the safety of CAIS and to test whether CAIS improves quality of life by using standardized outcomes assessment tools. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Patients (n = 29) were randomized (1:2) with the intent to treat with either a control (microfracture [MFX]) or an experimental (CAIS) procedure. Patients were followed at predetermined time points for 2 years using several standardized outcomes assessment tools (SF-36, International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS]). Magnetic resonance imaging was performed at baseline, 3 weeks, and 6, 12, and 24 months. Results: Lesion size and International Cartilage Repair Society (ICRS) grade were similar in both groups. General outcome measures (eg, physical component score of the SF-36) indicated an overall improvement in both groups, and no differences in the number of adverse effects were noted in comparisons between the CAIS and MFX groups. The IKDC score of the CAIS group was significantly higher (73.9 ± 14.72 at 12 months and 82.95 ± 14.88 at 24 months) compared with the MFX group (57.78 ± 18.31 at 12 months and 59.5 ± 13.44 at 24 months). Select subdomains (4/5) in the KOOS instrument were significantly different at 12 and 18 months, and all subdomains (Symptoms and Stiffness, Pain, Activities of Daily Living, Sports and Recreation, Knee-related Quality of Life) were significantly increased at 24 months in CAIS with scores of 88.47 ± 11.68, 90.64 ± 7.87, 97.29 ± 3.8, 78.16 ± 22.06, and 69 ± 23.15 compared with 75 ± 9.31, 78.94 ± 13.73, 89.46 ± 8.13, 51.67 ± 26.01, and 37.15 ± 21.67 in the MFX group. These significant improvements were maintained at 24 months in both IKDC and KOOS. Qualitative analysis of the imaging data did not note differences between the 2 groups in fill of the graft bed, tissue integration, or presence of subchondral cysts. Patients treated with MFX had a significantly higher incidence of intralesional osteophyte formation (54% and 70% of total number of lesions treated) at 6 and 12 months when compared with CAIS (8% and 25% of total number of lesions treated). Conclusion: The first clinical experience in using CAIS for treating patients with focal chondral defects indicates that it is a safe, feasible, and effective method that may improve long-term clinical outcomes.

Treatment of Advanced Primary and Recurrent Diffuse Pigmented Villonodular Synovitis of the Knee

Background: Diffuse pigmented villonodular synovitis of the knee is a difficult tumor to eradicate. We report our experience with a combined open posterior and anterior synovectomy with and without adjuvant postoperative radiation therapy in patients with advanced extracapsular disease.Methods: A single surgeon operated on forty patients, with an average age of thirty-five years (range, fourteen to sixty-eight years), who had diffuse pigmented villonodular synovitis of the knee. All patients had been referred to us after having initially undergone arthroscopic or open surgical procedures without eradication of the disease. Patients were retrospectively placed into one of three groups: Group I received surgery alone (five patients), Group II had surgery and intra-articular radiation synovectomy with use of dysprosium-165 (thirty patients), and Group III had surgery and external beam radiation (five patients). Adjuvant radiation was performed three months postoperatively. Magnetic resonance imaging was used for all patients for preoperative staging and postoperative follow-up.Results: The average Knee Society score for the entire series improved from 61 points preoperatively to 92 points at the time of follow-up, at an average of five years (range, 1.5 to eight years) (p < 0.001). There was also a significant (p < 0.001) increase in the average range of motion of the knees across all groups. On the basis of the Knee Society scores, thirty-seven patients (93%) had a good or excellent result, two patients had a fair result, and one patient had a poor result. Complications included stiffness requiring manipulation in three knees, one case of reflex sympathetic dystrophy, advanced osteoarthritis leading to a total knee replacement in four patients, and seven recurrences (a prevalence of 18%) after operative treatment and radiation therapy.Conclusions: This surgical technique allows excellent visualization and removal of intra-articular and extra-articular diffuse pigmented villonodular tissue and yields excellent functional results and a low prevalence of knee stiffness. However, the rate of recurrence detected by magnetic resonance imaging was 18%. Adjuvant intra-articular radiation therapy may be beneficial for eradication of small foci of residual disease, but complete resection of all pigmented villonodular tissue appears to be the key to preventing recurrence. Magnetic resonance imaging was essential for accurate preoperative staging of the tumor and for follow-up since the presence of residual disease did not reliably correlate with the clinical findings. Patients with minimal degenerative arthritis and primary or recurrent extra-articular disease will benefit most from this approach.

Magnetic resonance imaging of autologous chondrocyte implantation

There is now over 10 years experience with autologous chondrocyte implantation (ACI) for the management of full-thickness chondral injuries in the knee. This article briefly reviews the surgical procedure, the time lines of graft maturation, and patient rehabilitation in the context of postoperative magnetic resonance imaging (MRI) assessment. The normal and abnormal appearances of ACI repair cartilage on MR images are described, with an emphasis on the MR appearances of the complications that may occur after this procedure, and the usefulness of MR imaging for the surgeon.

MR imaging of cartilage repair procedures

It is becoming increasingly important for the radiologist to evaluate the appearance and outcome of cartilage repair procedures. MR imaging is currently the best method for such evaluation but it is necessary to use cartilage-specific sequences and to modify those sequences when necessary to minimize artifacts from retained metal within the joint. This article reviews the surgical technique of the more commonly performed cartilage repair procedures, currently recommended techniques for the MR imaging evaluation of articular cartilage and cartilage repair procedures, and the MR imaging appearance of cartilage repair procedures and of the most frequently encountered complications following such procedures.

MRI-guided percutaneous cryotherapy for soft-tissue and bone metastases: initial experience.

OBJECTIVE We sought to determine the safety and feasibility of percutaneous MRI-guided cryotherapy in the care of patients with refractory or painful metastatic lesions of soft tissue and bone adjacent to critical structures. MATERIALS AND METHODS Twenty-seven biopsy-proven metastatic lesions of soft tissue (n = 17) and bone (n = 10) in 22 patients (15 men, seven women; age range, 24-85 years) were managed with MRI-guided percutaneous cryotherapy. The mean lesion diameter was 5.2 cm. Each lesion was adjacent to or encasing one or more critical structures, including bowel, bladder, and major blood vessels. A 0.5-T open interventional MRI system was used for cryoprobe placement and ice-ball monitoring. Complications were assessed for all treatments. CT or MRI was used to determine local control of 21 tumors. Pain palliation was assessed clinically in 19 cases. The mean follow-up period was 19.5 weeks. RESULTS Twenty-two (81%) of 27 tumors were managed without injury to adjacent critical structures. Two patients had transient lower extremity numbness, and two had both urinary retention and transient lower extremity paresthesia. One patient had chronic serous vaginal discharge, and one sustained a femoral neck fracture at the ablation site 6 weeks after treatment. Thirteen (62%) of the 21 tumors for which follow-up information was available either remained the same size as before treatment or regressed. Eight tumors progressed (mean local progression-free interval, 5.6 months; range, 3-18 months). Pain was palliated in 17 of 19 patients; six of the 17 experienced complete relief, and 11 had partial relief. CONCLUSION MRI-guided percutaneous cryotherapy for metastatic lesions of soft tissue and bone adjacent to critical structures is safe and can provide local tumor control and pain relief in most patients.