Brett Lurie

MR Imaging of Hip Arthroplasty Implants

Hip arthroplasty has become the standard treatment for end-stage hip disease, allowing pain relief and restoration of mobility in large numbers of patients; however, pain after hip arthroplasty occurs in as many as 40% of cases, and despite improved longevity, all implants eventually fail with time. Owing to the increasing numbers of hip arthroplasty procedures performed, the demographic factors, and the metal-on-metal arthroplasty systems with their associated risk for the development of adverse local tissue reactions to metal products, there is a growing demand for an accurate diagnosis of symptoms related to hip arthroplasty implants and for a way to monitor patients at risk. Magnetic resonance (MR) imaging has evolved into a powerful diagnostic tool for the evaluation of hip arthroplasty implants. Optimized conventional pulse sequences and metal artifact reduction techniques afford improved depiction of bone, implant-tissue interfaces, and periprosthetic soft tissue for the diagnosis of arthroplasty-related complications. Strategies for MR imaging of hip arthroplasty implants are presented, as well as the imaging appearances of common causes of painful and dysfunctional hip arthroplasty systems, including stress reactions and fractures; bone resorption and aseptic loosening; polyethylene wear-induced synovitis and osteolysis; adverse local tissue reactions to metal products; infection; heterotopic ossification; tendinopathy; neuropathy; and periprosthetic neoplasms. A checklist is provided for systematic evaluation of MR images of hip arthroplasty implants. MR imaging with optimized conventional pulse sequences and metal artifact reduction techniques is a comprehensive imaging modality for the evaluation of the hip after arthroplasty, contributing important information for diagnosis, prognosis, risk stratification, and surgical planning.

All-Inside, Physeal-Sparing Anterior Cruciate Ligament Reconstruction Does Not Significantly Compromise the Physis in Skeletally Immature Athletes: A Postoperative Physeal Magnetic Resonance Imaging Analysis

Background: 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. Purpose: To utilize physeal-specific magnetic resonance imaging (MRI) to quantify the zone of physeal injury after all-inside ACL reconstruction in skeletally immature athletes. Study Design: Case series; Level of evidence, 4. Methods: Twenty-three skeletally immature patients (mean chronologic age 12.6 years; range, 10-15 years) were prospectively evaluated after all-inside ACL reconstruction. The mean bone age was 13.2 years. There were 8 females and 15 males. Fifteen patients underwent an all-epiphyseal (AE) ACL reconstruction and 8 patients had a partial transphyseal (PTP) ACL reconstruction, which spared the femoral physis but crossed the tibial physis. At 6 and 12 months postoperatively, MRI using 3-dimensional fat-suppressed spoiled gradient recalled echo sequences and full-length standing radiographs were performed to assess graft survival, growth arrest, physeal violation, angular deformity, and leg length discrepancy. Results: The mean follow-up for this cohort was 18.5 months (range, 12-39 months). Minimal tibial physeal violation was seen in 10 of 15 patients in the AE group and, by definition, all patients in the PTP group. The mean area of tibial physeal disturbance (±SD) was 57.8 ± 52.2 mm2 (mean 2.1% of total physeal area) in the AE group compared with 145.1 ± 100.6 mm2 (mean 5.4% of total physeal area) in the PTP group (P = .003). Minimal compromise of the femoral physis (1.5%) was observed in 1 case in the PTP group and no cases in the AE group. No cases of growth arrest, articular surface violation, or avascular necrosis were noted on MRI. No postoperative angular deformities or significant leg length discrepancies were observed. Conclusion: The study data suggest that all-inside ACL reconstruction is a safe technique for skeletally immature athletes at short-term follow-up. Physeal-specific MRI reveals minimal growth plate compromise that is significantly lower than published thresholds for growth arrest.

Comprehensive Analysis of a Recalled Modular Total Hip System and Recommendations for Management

BACKGROUND Recent total hip arthroplasty designs have introduced modularity at the neck-stem junction. There are reports of failure of this class of designs due to corrosion at the modular junction. The purpose of this study was to evaluate patients implanted with a recently recalled modular total hip arthroplasty system. METHODS This was a prospective study of 216 total hip arthroplasties in 195 patients performed by a single surgeon. All hips had a titanium-alloy stem, but 199 had a modular cobalt-chromium neck and seventeen were monolithic. The mean patient age was 65.4 years (range, twenty to eighty-eight years); seventy-nine were men and 116 were women. Patients were evaluated for infection and with metal ion assays and MRI (magnetic resonance imaging). Intraoperative tissue samples were graded, and retrieved implants were examined. RESULTS At a mean follow-up of 19.3 months, eighty (37%) of 216 hips had been revised. An adverse local tissue reaction (ALTR) was the cause for revision in seventy-three of these eighty hips; all had the modular neck design. Assay results for the patients requiring revision showed higher levels of cobalt (mean, 8.6 ng/mL) than chromium (mean, 1.8 ng/mL). MRI showed moderate to severe levels of synovial response in sixty-three of 166 hips. The mean ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) score for the revised hips was 8.1. Corrosion was visible on all tapers at the neck-stem junction but not the head-neck junction. CONCLUSIONS Early failures of modular total hip arthroplasty occur due to fretting and corrosion at the neck-stem junction, resulting in ALTR. Surveillance utilizing metal ion levels and MRI may be indicated for all patients regardless of symptoms, as the early survivorship is poor and the ultimate failure rate may be catastrophically high.

MR Imaging of Adverse Local Tissue Reactions around Rejuvenate Modular Dual-Taper Stems

PURPOSE To describe the magnetic resonance (MR) imaging characteristics associated with adverse local tissue reactions and tissue damage around hip arthroplasties in which the recalled Rejuvenate modular dual-taper stem was used. MATERIALS AND METHODS The institutional review board of the Hospital for Special Surgery approved the study. All study patients provided informed consent. MR imaging studies were retrospectively reviewed in a cohort of 58 patients with 66 hip arthroplasties with Rejuvenate stems who had presented for imaging evaluation because of recall of the implant. Multiple regression analysis was used to examine MR imaging features, biomechanical factors, and metal ion levels as predictors of aseptic lymphocytic vasculitis-associated lesion (ALVAL) score at histologic assessment while adjusting for age and sex for 54 revised hips. RESULTS Revision surgery was performed in 54 hips on the basis of clinical or imaging findings (24% of hips were completely asymptomatic). The median ALVAL score among the revised hips was 9 (range, 1-10). Imaging characteristics observed with high frequency in patients with ALVAL included synovitis, mixed- or solid-type synovitis, synovial thickening, and capsular dehiscence. CONCLUSION MR imaging provides an effective noninvasive method for assessing the presence and severity of adverse local tissue reaction, as well as the degree of pre-existing tissue damage, thereby facilitating early and accurate identification of candidates for revision surgery.

MR Imaging of Knee Arthroplasty Implants

Primary total knee arthroplasty is a highly effective treatment that relieves pain and improves joint function in a large percentage of patients. Despite an initially satisfactory surgical outcome, pain, dysfunction, and implant failure can occur over time. Identifying the etiology of complications is vital for appropriate management and proper timing of revision. Due to the increasing number of knee arthroplasties performed and decreasing patient age at implantation, there is a demand for accurate diagnosis to determine appropriate treatment of symptomatic joints following knee arthroplasty, and for monitoring of patients at risk. Magnetic resonance (MR) imaging allows for comprehensive imaging evaluation of the tissues surrounding knee arthroplasty implants with metallic components, including the polyethylene components. Optimized conventional and advanced pulse sequences can result in substantial metallic artifact reduction and afford improved visualization of bone, implant-tissue interfaces, and periprosthetic soft tissue for the diagnosis of arthroplasty-related complications. In this review article, we discuss strategies for MR imaging around knee arthroplasty implants and illustrate the imaging appearances of common modes of failure, including aseptic loosening, polyethylene wear-induced synovitis and osteolysis, periprosthetic joint infections, fracture, patellar clunk syndrome, recurrent hemarthrosis, arthrofibrosis, component malalignment, extensor mechanism injury, and instability. A systematic approach is provided for evaluation of MR imaging of knee implants. MR imaging with optimized conventional pulse sequences and advanced metal artifact reduction techniques can contribute important information for diagnosis, prognosis, risk stratification, and surgical planning.

Three-dimensional magnetic resonance imaging of physeal injury: reliability and clinical utility

Background: Injuries to the physis are common in children with a subset resulting in an osseous bar and potential growth disturbance. Magnetic resonance imaging allows for detailed assessment of the physis with the ability to generate 3-dimensional physeal models from volumetric data. The purpose of this study was to assess the interrater reliability of physeal bar area measurements generated using a validated semiautomated segmentation technique and to highlight the clinical utility of quantitative 3-dimensional (3D) physeal mapping in pediatric orthopaedic practice. Methods: The Radiology Information System/Picture Archiving Communication System (PACS) at our institution was searched to find consecutive patients who were imaged for the purpose of assessing a physeal bar or growth disturbance between December 2006 and October 2011. Physeal segmentation was retrospectively performed by 2 independent operators using semiautomated software to generate physeal maps and bar area measurements from 3-dimensional spoiled gradient recalled echo sequences. Inter-reliability was statistically analyzed. Subsequent surgical management for each patient was recorded from the patient notes and surgical records. Results: We analyzed 24 patients (12M/12F) with a mean age of 11.4 years (range, 5-year to 15-year olds) and 25 physeal bars. Of the physeal bars: 9 (36%) were located in the distal tibia; 8 (32%) in the proximal tibia; 5 (20%) in the distal femur; 1 (4%) in the proximal femur; 1 (4%) in the proximal humerus; and 1 (4%) in the distal radius. The independent operator measurements of physeal bar area were highly correlated with a Pearson correlation coefficient (r) of 0.96 and an intraclass correlation coefficient for average measures of 0.99 (95% confidence interval, 0.97-0.99). Four patients underwent resection of the identified physeal bars, 9 patients were treated with epiphysiodesis, and 1 patient underwent bilateral tibial osteotomies. Conclusions: Semiautomated segmentation of the physis is a reproducible technique for generating physeal maps and accurately measuring physeal bars, providing quantitative and anatomic information that may inform surgical management and prognosis in patients with physeal injury. Level of Evidence: Level IV.

Magnetic Resonance Imaging of the Hip Labrum, Capsule, and Synovium

Magnetic resonance imaging (MRI) is the imaging modality of choice in the preoperative and postoperative assessment of patients undergoing hip arthroscopy. MRI offers high soft tissue contrast, sensitivity to fluid, and direct multi-planar acquisition and avoids exposure to ionizing radiation. With attention to scan parameters, accurate and reproducible imaging can be obtained allowing for precise assessment of the labrum, capsule, synovium, and cartilage. The MRI appearance of the labrum, capsule, and synovium is discussed with reference to the most common pathologies encountered at hip arthroscopy.

MR Imaging in Patients with Ulnar Collateral Ligament Injury

Magnetic resonance imaging (MRI) offers unparalleled soft tissue contrast resolution, direct multiplanar imaging capabilities, and high-spatial resolution, allowing for reproducible, accurate preoperative diagnosis of ulnar collateral ligament (UCL) abnormalities. The UCL of the elbow may be injured acutely or as a result of chronic repetitive valgus stress. MRI of the injured and the reconstructed UCL is discussed, with reference to associated findings in the setting of acute UCL injury and chronic valgus extension overload.

Physeal-Specific MRI Analysis of Growth Plate Disturbance Following All-Inside Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients: Does a Physeal-Sparing Technique Offer any Advantage?

Objectives: The decision to perform anterior cruciate ligament (ACL) reconstruction in skeletally immature patients carries a risk of growth disturbance due to iatrogenic physeal injury. Multiple physeal-sparing techniques have been described but none, to our knowledge combine the benefits of an anatomic reconstruction and socket fixation, without violation of either the femoral or tibial physis at any stage of the procedure. The purpose of this study was to compare the incidence and calculate the area of post-operative physeal disturbances, using a physeal-sensitive magnetic resonance imaging (MRI) sequence*, between all-epiphyseal (AE) and partial transphyseal (PTP) ACL reconstructions in a cohort of skeletally-immature patients. Methods: Twenty-one skeletally immature patients with a mean chronologic age of 12.7 years (range 10 to 16) undergoing all-inside ACL reconstruction were prospectively followed. Fourteen patients had an all-epiphyseal (AE) ACL reconstruction and 7 patients had a partial transphyseal (PTP) ACL reconstruction, which spared the femoral physis but crossed the tibial physis. Hamstring autograft was used in all cases. At a mean of 11.6 months follow-up, all patients were assessed for focal physeal disturbance and graft survival using a three-dimensional (3D) fat suppressed spoiled gradient-recalled echo (SPGR) MRI sequence. Angular deformity and leg length discrepancy were evaluated on full-length standing radiographs. The International Knee Documentation Committee (IKDC) subjective score and Lysholm knee score were also documented. Results: The tibial physis was violated in 13/14 patients in the AE group and all patients in the PTP group. The mean area of post-operative tibial physeal disturbance (± SD) was 42.4 ± 38.6 mm2 (mean 1.7% of total physeal area) in the AE group compared to 216.7 ± 129.1 mm2 (mean 7.3% of total physeal area) in the PTP group (p = 0.003). The femoral physis was violated in one case in both groups resulting in a mean physeal disturbance of 1.5% of the total distal femoral physeal area. No cases of fracture, articular surface violation or avascular necrosis were noted on MRI in either group. Short-term graft survival was 100% amongst the entire cohort. There were no cases of angular deformity in either group with a mean side-side difference in the lateral distal femoral angle of 1.11° ± 1.02° in the AE group and 0.72° ± 0.65° in the PTP group (p = 0.23). No significant leg-length discrepancies were measured in either group. The mean IKDC and Lysholm scores (± SD) were 93.3 ± 5.9 and 97.8 ± 3.8 respectively in the AE group and 87.7 ± 3.5 and 96 ± 5.2 respectively in the PTP group. Conclusion: All-epiphyseal ACL reconstruction caused significantly less focal physeal disturbance than PTP ACL reconstruction, as determined by a 3D physeal-sensitive MRI sequence. Neither technique however resulted in angular deformity or leg-length discrepancy at early follow-up. Both all-inside ACL reconstruction techniques used in this study are safe and effective at early follow-up in skeletally immature patients. Further longitudinal study of this cohort is required to determine any potential advantages of a purely physeal-sparing technique.