[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to evaluate whether patients with bilateral metal-on-metal (MoM) hip
replacements have symmetric adverse local tissue reactions (ALTRs) at follow-up. An MRI of both hips was
performed at a mean time of six years after surgery in 43 patients. The prevalence and severity of ALTRs were found to be similar in simultaneous hips but differences were observed in sequential hips. The order and timing of sequential hip arthroplasties did not affect the severity of ALTRs. Thus, in addition to metal ion exposure from an earlier MoM implant other factors may also play a role in the progression of ALTRs. Bilateral implants should be given special consideration in risk stratification algorithms for management of patients with MoM hip arthroplasty.
The Journal of Arthroplasty 10/2015; 30(10):1794-1798. · 2.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Adverse local tissue reactions (ALTRs) around hip arthroplasties are an important reason for failure of metal-on-metal (MoM) hip implants. Little is known about capsular dehiscence patterns as ALTRs decompress from the hip into the surrounding tissue planes; these patterns may also influence the onset and severity of patient symptoms.
Through a multicenter study approach, we asked: (1) Is ALTR location related to the surgical approach used for arthroplasty in patients who underwent hip arthroplasty (resurfacing or THA) with a single, recalled hip arthroplasty system? (2) Do ALTR severity and location affect patient-reported outcomes in these patients? (3) Is ALTR severity different between patients who received the resurfacing version of this component (Articular Surface Replacement [ASR]) and those who received the THA implant in this system (ASR XL)?
In a multicenter prospective study of patients who had undergone surgery with use of the ASR and ASR XL hip system (DePuy Orthopaedics, Warsaw, IN, USA), 288 patients (333 hips) from two centers had a metal artifact reduction sequence MRI of the hip performed at a mean time of 6 years postsurgery. Procedures included 166 hips (50%) with ASR resurfacing and 167 hips (50%) with ASR XL THA performed between 2004 and 2010. One hundred twenty-nine hips (39%) had been operated on using a direct lateral approach and 204 using a posterior approach (61%). The EQ-5D, Harris hip score, UCLA activity score, and visual analog scale pain score were obtained for each patient. ALTRs were classified using the Anderson ALTR grading system, and the location, synovial thickness, and diameter of the ATLRs were assessed. The relationship between ALTR location and surgical approach as well as for ALTR severity and patient-reported outcomes were evaluated, and logistic regression was used to identify predictors for moderate-to-severe ALTRs.
Moderate or severe ALTRs were identified in 79 hips (24%); 41 of these hips had been operated on using the direct lateral approach and 38 using the posterior approach. In patients in whom the lateral approach was used, 83% had an anterior ALTR. Similarly, 71% of patients in the posterior approach group had posterior ALTRs. There were no differences in patient-reported outcome measures between patients with moderate-to-severe ALTRs and those with no ALTR findings on MRI (p > 0.09). Use of ASR XL was an independent risk factor for moderate-to-severe ALTRs (odds ratio, 2.8; 95% confidence interval, 1.4-5.5 p = 0.004) and patients with ASR XL also had a thicker synovium (median ASR XL = 3.6 mm [1.2-10.6 mm], median ASR = 2.6 mm [1.2-10.7 mm], p < 0.001) and larger maximal ALTR diameter (median ASR XL = 47.6 mm [14-109.70 mm], median ASR = 38.4 [17.2-118.0 mm], p = 0.02) than patients treated with ASR.
The location of ALTRs can be predicted based on the previous surgical approach to the hip. Patients with ASR XL are more likely to develop moderate-to-severe ALTRs compared with ASR patients. An extensive range of patient-reported outcome measures may not identify all patients with ALTRs further supporting the use of MRI as a screening measure for ALTRs.
Level II, therapeutic study.
Clinical Orthopaedics and Related Research 08/2015; DOI:10.1007/s11999-015-4456-x · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: PURPOSE/AIM
Discuss optimization strategies for MRI of knee arthroplasty and the utility of dedicated metal artifact reduction pulse sequences Review the normal MRI appearances of knee arthroplasty Systematically illustrate the MRI diagnoses of arthroplasty-associated complications
The role of MRI following knee arthroplasty Optimized MR imaging protocol, MR angiography and dedicated metal artifact reduction pulse sequences Normal MRI appearances and MRI diagnosis of complications: Fibrous membrane formation, bone resorption and aseptic loosening Polyethylene wear-induced synovitis and osteolysis Infection, non-specific synovitis and arthrofibrosis Impingement syndromes and patellar clunk Recurrent hemarthrosis – MR angiography assessment Stress reactions and fractures Component rotational alignment Polyethylene displacement Instability and excessive soft tissue balancing Musculotendinous abnormalities Neurovascular compromise
Optimized and dedicated MRI techniques reduce metal artifacts and improve our ability to assess and differentiated knee arthroplasty-associated complications. MRI is accurate for the diagnosis of bone resorption, synovitis, malalignment and hemarthrosis and can detect infection, muscle, tendon and nerve abnormalities.
Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 08/2015
[Show abstract][Hide abstract] ABSTRACT: Background: Osteochondral autografts and allografts have been widely used in the treatment of isolated Grade IV articular cartilage lesions of the knee. However, there is paucity in the literature with regards to the basic science investigating the direct comparison between fresh osteochondral allografts to autografts.
Hypothesis: At twelve months, fresh osteochondral allografts are equal to autografts with respect to function, bony incorporation into host bone and chondrocyte viability.
Study Design: Prospective comparative in-vivo animal model study
Methods: Eight adult mongrel dogs underwent bilateral hind limb osteochondral graft implantation in the knee after creation of an Outerbridge Grade IV cartilage defect. One hind limb knee received an autograft, and the contralateral knee received an allograft. All dogs were sacrificed at twelve months. Graft analysis included gross examination, radiographs, magnetic resonance imaging, biomechanical testing and histology.
Results: Magnetic resonance imaging demonstrated excellent bony incorporation of both autografts and allografts, except one allograft, which revealed partial incorporation. Histologic examination of cartilage showed intact hyaline appearance for both autografts and allografts, with fibrocartilage at the interface of both. Biomechanical testing demonstrated no significant difference between allografts and autografts (p=0.76). Furthermore, no significant difference was observed between allografts and the native cartilage with biomechanical testing (p=0.84).
Conclusions: After 12 months from time of implantation, fresh osteochondral allograft and autograft tissue are not statistically different with respect to biomechanical properties, bony incorporation and chondrocyte viability.
Western Orthopedic Association Annual Meeting, Couer d'Alene, Idaho; 08/2015
[Show abstract][Hide abstract] ABSTRACT: Magnetic resonance imaging (MRI) visualization of meniscal signal is particularly challenging as the highly organized ultrastructure of meniscal fibrocartilage yields very short T2 values (∼6 ms) and a paucity of signal intensity during conventional image acquisition.
The purpose of this study was to evaluate the feasibility of imaging postoperative menisci using an experimental, quantitative ultrashort echo time (UTE) MRI pulse sequence. This sequence acquires short echo images (echo time (TE) ∼0.3 ms) to produce multi-echo images for quantitative T2* calculations that provide an objective measure of collagen organization.
MRI scans of the knee were acquired at 6- and 12-month intervals on a clinical 3.0 T scanner following meniscal surgery in eight patients (ages 13-41), four of whom underwent repair and the other four partial meniscectomy. Conventional MRI sequences were qualitatively evaluated for meniscal morphology and signal and correlated with quantitative UTE results.
A wide range of mean T2* values for both postsurgical groups was measured, and these values changed for each patient between the 6- and 12-month intervals. In many instances, the UTE sequence demonstrated quantitative differences between the two time intervals that were not detected with conventional sequences.
This pilot study presents preliminary, observational data to be used as a baseline for future studies. Although the T2* values did not reveal a trend in either group or correlate with expected signal changes on conventional MRI, we speculate that the UTE sequence may detect ultrastructural alterations in meniscal composition that are otherwise not perceived with routine fast spin echo (FSE) sequences.
[Show abstract][Hide abstract] ABSTRACT: The enhanced posterior soft tissue repair has reduced the frequency of dislocation after primary THA performed through the posterolateral approach. However, the long-term integrity of the repair is unknown and could influence surgeon choice regarding surgical technique and THA approach.
We asked: (1) What is the durability of the enhanced posterior soft tissue repair at a minimum of 49 months using MRI to evaluate soft tissue to bone integrity? (2) How does the appearance of the posterior soft tissues change during this time? (3) Are there patient characteristics associated with the long-term imaging appearance of the posterior repair?
All patients without a contraindication for MRI who were undergoing unilateral primary uncemented THA through a posterior approach between February and May 2005 were eligible for inclusion. Ninety percent consented to participate (36 of 40 patients), and 30 patients were followed prospectively with MRI postoperatively and again at 3 months; of those, 22 (73%; 12 men, 10 women) completed the study by having another MRI study at a minimum of 49 months (mean, 51 months; range, 49-59 months). Each patient underwent metal-artifact-reduction sequence MRI to evaluate the integrity of the posterior soft tissues, which had been repaired anatomically during primary THA at a minimum of 4 years earlier. The results were compared with those of prior MR images obtained immediately after surgery and at 3 months postoperatively. All patients were given a self-reported modified Harris hip score at the time of the most recent MRI study (maximum score = 81).
At latest followup, 21 of 22 (96%) patients had a posterior capsule in contact with bone, and 21 of 22 (96%) had an intact quadratus femoris. Twenty-one patients (96%) had soft tissue or a scar from the piriformis and conjoined tendons in continuity with bone. In these cases, the interface between the piriformis and conjoined tendons and the greater trochanter observed immediately postoperatively and at 3 months postoperatively became filled with hypointense tissue, with signal characteristics similar to tendon. Time from surgery was most associated with changes in native tendon-to-bone distances (p < 0.001) and MRI signal intensity of the repair (p < 0.001).
At followup of just more than 4 years, the posterior capsule and quadratus femoris most often were healed to bone. In the majority of patients, scar tissue between the piriformis and conjoined tendons and bone matured to achieve orientation and signal intensity resembling native tendon. We believe the enhanced posterior soft tissue repair facilitates this process. Our results provide a plausible explanation for improved postoperative stability observed in patients receiving an enhanced soft tissue repair compared with those in whom a repair is not performed.
Level IV, therapeutic study.
Clinical Orthopaedics and Related Research 06/2015; 473(10). DOI:10.1007/s11999-015-4380-0 · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Analysis of fresh specimens in research studies is ideal; however, it is often necessary to freeze samples for evaluation at a later time. Limited evaluation of the effect of freeze-thawing of tendon tissue samples on inherent magnetic resonance imaging (MRI) parameters, such as ultrashort echo time (UTE) T2* values, have been performed to date.
This study performed UTE MRI on 14 bovine patellar tendons at harvest and after four consecutive freeze-thaw cycles.
Results demonstrated a small but significant reduction (12%) in tendon T2* values after the first freeze thaw cycle, but not after successive cycles. Tendons from juvenile animals with open physis had a significant reduction of T2* following a single freeze thaw cycle, P<0.0001.
The results of this study emphasize the importance of using uniform tendon storage protocols when using UTE MRI in preclinical models.
[Show abstract][Hide abstract] ABSTRACT: Optimization of metal artifact reduction pulse sequences over the past decade has rendered MRI valuable in knee arthroplasty assessment. MRI can reliably predict the presence and extent of infection, component loosening and polyethylene wear, and component malrotation, and it can evaluate the integrity of surrounding soft tissue structures. Using dynamic contrast-enhanced angiographic techniques, vascular pathology such as pseudoaneurysm formation and recurrent hemarthrosis can also be assessed.
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
[Show abstract][Hide abstract] ABSTRACT: Reason for performing studyPostoperative imaging in subjects with orthopaedic implants is challenging across all modalities. Magnetic resonance imaging (MRI) is preferred to assess human postoperative musculoskeletal complications, as soft tissue and bones are evaluated without using ionising radiation. However, with conventional MRI pulse sequences, metal creates susceptibility artifact that distorts anatomy. Assessment of the postoperative equine patient is arguably more challenging due to the volume of metal present, and MRI is often not performed in horses with implants. Novel pulse sequences such as multi-acquisition variable resonance image combination (MAVRIC) now provide improved visibility in the vicinity of surgical-grade implants and offer an option for imaging horses with metal implants.Objectives
To compare conspicuity of regional anatomy in an equine fracture-repair model using MAVRIC, narrow receiver bandwidth fast spin echo (NBW FSE), and wide receiver bandwidth (WBW) FSE sequences.Study DesignNon-randomised in vitro experiment.MethodsMAVRIC, NBW FSE and WBW FSE were performed on 9 cadaveric distal limbs with fractures and stainless steel implants in the 3rd metacarpal bone and proximal phalanx. Objective measures of artifact reduction were performed by calculating the total artifact area in each transverse image as a percentage of the total anatomic area. The number of transverse images in which fracture lines were visible was tabulated for each sequence. Regional soft tissue conspicuity was assessed subjectively.ResultsOverall anatomic delineation was improved using MAVRIC compared to NBW FSE; delineation of structures closest to the metal implants was improved using MAVRIC compared to WBW FSE and NBW FSE. Total artifact area was the highest for NBW FSE and lowest for MAVRIC; the total number of transverse slices with a visible fracture line was highest in MAVRIC and lowest in NBW FSE.ConclusionMAVRIC and WBW FSE are feasible additions to minimise artifact around implants.
[Show abstract][Hide abstract] ABSTRACT: Anterior cruciate ligament (ACL) reconstruction in skeletally immature patients can result in growth disturbance due to iatrogenic physeal injury. Multiple physeal-sparing ACL reconstruction techniques have been described; however, few combine the benefits of anatomic reconstruction using sockets without violation of the femoral or tibial physis.
The American Journal of Sports Medicine 10/2014; 42(12). DOI:10.1177/0363546514552994 · 4.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Magnetic resonance (MR) imaging evaluation of the painful failed shoulder arthroplasty is a useful imaging modality due to advancements in metal artifact reduction techniques, which allow assessment of the integrity of the supporting soft-tissue envelope and the implant.
The focus of this pictorial review is to illustrate the benefits of MR imaging, whether used alone or as an adjunct to other imaging modalities, in aiding the clinician in the complex decision making process.
A PubMed (MEDLINE) search focusing on the complications and imaging assessment of shoulder arthroplasty was performed. Articles were selected for review based on their pertinence to the aforementioned topics.
We discuss the ability of MR imaging to identify why a patient’s arthroplasty may have failed. Specific causes including component loosening and implant failure, rotator cuff and deltoid integrity, infection, subtle fractures, and nerve pathology are reviewed, with illustrative sample images.
MRI is a valuable tool in the assessment for pathology in the shoulder following arthroplasty.
[Show abstract][Hide abstract] ABSTRACT: Tendinopathy affects individuals who perform repetitive joint motion. Magnetic resonance imaging (MRI) is frequently used to qualitatively assess tendon health, but quantitative evaluation of inherent MRI properties of loaded tendon has been limited. This study evaluated the effect of cyclic loading on [Formula: see text] values of fresh and frozen rabbit patellar tendons using ultra short echo (UTE) MRI. Eight fresh and 8 frozen rabbit lower extremities had MR scans acquired for tendon [Formula: see text] evaluation. The tendons were then manually cyclically loaded for 100 cycles to 45N at approximately 1Hz. The MR scanning was repeated to reassess the [Formula: see text] values. Analyses were performed to detect differences of tendon [Formula: see text] values between fresh and frozen samples prior to and after loading, and to detect changes of tendon [Formula: see text] values between the unloaded and loaded configurations. No difference of [Formula: see text] was found between the fresh and frozen samples prior to or after loading, p=0.8 and p=0.1, respectively. The tendons had significantly shorter [Formula: see text] values, p=0.023, and reduced [Formula: see text] variability, p=0.04, after cyclic loading. Histologic evaluation confirmed no induced tendon damage from loading. Shorter [Formula: see text] , from stronger spin-spin interactions, may be attributed to greater tissue organization from uncrimping of collagen fibrils and lateral contraction of the tendon during loading. Cyclic tensile loading of tissue reduces patellar tendon [Formula: see text] values and may provide a quantitative metric to assess tissue organization.
Journal of Biomechanics 09/2014; 47(13). DOI:10.1016/j.jbiomech.2014.08.018 · 2.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
The purpose of this article is to explain the basic physics of imaging patients with metal implants, explain conflicting information regarding MRI scanning of "MR Conditional" devices, and relate our experience of scanning total joint arthroplasty (TJA) at our institution.
MRI near TJA is effective with appropriate imaging protocols and standardized safety precautions. Strict adherence to MR Conditional labeling may preclude broad use of MRI for TJA assessment.
American Journal of Roentgenology 07/2014; 203(1):154-61. DOI:10.2214/AJR.13.11991 · 2.73 Impact Factor