MRI Predicts ALVAL and tissue damage in metal-on-metal hip arthroplasty

Adult Reconstruction and Joint Replacement Division Surgery, Hospital for Special Surgery, New York, NY, USA.
Clinical Orthopaedics and Related Research (Impact Factor: 2.77). 01/2013; 472(2). DOI: 10.1007/s11999-013-2788-y
Source: PubMed


BACKGROUND: Adverse local tissue reactions (ALTR) around metal-on-metal (MOM) hip arthroplasties are increasingly being recognized as a cause of failure. These reactions may be associated with intraoperative tissue damage and complication rates as high as 50% after revision. Although MRI can identify ALTR in MOM hips, it is unclear whether the MRI findings predict those at revision surgery. QUESTIONS/PURPOSES: We therefore (1) identified which MRI characteristics correlated with histologically confirmed ALTR (using the aseptic lymphocytic vasculitis-associated lesions [ALVAL] score) and intraoperative tissue damage and (2) developed a predictive model using modified MRI to detect ALVAL and quantify intraoperative tissue damage. METHODS: We retrospectively reviewed 68 patients with failed MOM hip arthroplasties who underwent preoperative MRI and subsequent revision surgery. Images were analyzed to determine synovial volume, osteolysis, and synovial thickness. The ALVAL score was used to grade tissue samples, thus identifying a subset of patients with ALTR. Intraoperative tissue damage was graded using a four-point scale. Random forest analysis determined the sensitivity and specificity of MRI characteristics in detecting ALVAL (score ≥ 5) and intraoperative tissue damage. RESULTS: Maximal synovial thicknesses and synovial volumes as determined on MRI correlated with the ALVAL score and were higher in cases of severe intraoperative tissue damage. Our MRI predictive model showed sensitivity and specificity of 94% and 87%, respectively, for detecting ALVAL and 90% and 86%, respectively, for quantifying intraoperative tissue damage. CONCLUSIONS: MRI is sensitive and specific in detecting ALVAL and tissue damage in patients with MOM hip implants. MRI can be used as a screening tool to guide surgeons toward timely revision surgery. LEVEL OF EVIDENCE: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

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Available from: Danyal H Nawabi, Jul 15, 2014
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    • "ease and relationship of the abnormality to normal anatomy can readily be appreciated . MARS MRI has been reliably and extensively used to investigate MOM hip complications (Sabah et al. 2011, Hayter et al. 2012a, Thomas et al. 2013, Nawabi et al. 2013) and has been shown to permit early diagnosis of pseudotumor and other soft tissue pathologies (Toms et al. 2008) associated with pain, loss of function, and higher revision rates. However, the use of MARS MRI is limited by susceptibility artifact at the prosthesis-bone interface, local availability, patient compliance, and cost. "
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    ABSTRACT: Background and purpose — Metal artifact reduction sequence (MARS) MRI is widely advocated for surveillance of metal-on-metal hip arthroplasties (MOM-HAs). However, its use is limited by susceptibility artifact at the prosthesis-bone interface, local availability, patient compliance, and cost (Hayter et al. 2011a). We wanted to determine whether CT is a suitable substitute for MARS MRI in evaluation of the painful MOM-HA. Patients and methods — 50 MOM-HA patients (30 female) with unexplained painful prostheses underwent MARS MRI and CT imaging. 2 observers who were blind regarding the clinical data objectively reported the following outcomes: soft tissue lesions (pseudotumors), muscle atrophy, and acetabular and femoral osteolysis. Diagnostic test characteristics were calculated. Results — Pseudotumor was diagnosed in 25 of 50 hips by MARS MRI and in 11 of 50 by CT. Pseudotumors were classified as type 1 (n = 2), type 2A (n = 17), type 2B (n = 4), and type 3 (n = 2) by MARS MRI. CT did not permit pseudotumor classification. The sensitivity of CT for diagnosis of pseudotumor was 44% (95% CI: 25–65). CT had “slight” agreement with MARS MRI for quantification of muscle atrophy (κ = 0.23, CI: 0.16–0.29; p < 0.01). Osteolysis was identified in 15 of 50 patients by CT. 4 of these lesions were identified by MARS MRI. Interpretation — CT was found to be superior to MRI for detection of osteolysis adjacent to MOM-HA, and should be incorporated into diagnostic algorithms. CT was unable to classify and failed to detect many pseudotumors, and it was unreliable for assessment of muscle atrophy. Where MARS MRI is contraindicated or unavailable, CT would be an unsuitable substitute and other modalities such as ultrasound should be considered
    Acta Orthopaedica 09/2014; 85(6). DOI:10.3109/17453674.2014.964618 · 2.77 Impact Factor
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    • "Recently, periacetabular osteolysis has been described as a reason for revision in modular MoM THA [12–14]. While the clinical value of metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) in the assessment of periprosthetic soft tissues is well documented [15, 16]; the best image modality to detect periacetabular osteolysis around metal-on-metal implants remains unclear [13, 17–19]. "
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    ABSTRACT: Objective Osteolysis has not been recognized as a common failure mode of the Birmingham modular metal-on-metal (MoM) total hip arthroplasty (THA). The clinical value of metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) to assess the periprosthetic soft tissue is well documented; however, the appropriate image modalities to detect periacetabular osteolysis remain unclear. Case summary Eleven patients with periacetabular osteolysis within 3–6 years after uncemented Birmingham modular MoM THA with a synergy stem are presented. All 11 patients received corresponding standardized AP pelvis radiographs, high-quality MARS MRIs and CT scans with a metal artifact reduction sequence. While periacetabular osteolysis around MoM THA was not detected on MARS MRI in ten patients, CT imaging identified osteolysis in all patients. Periacetabular osteolysis appears to be a failure mechanism of the Smith & Nephew Birmingham MoM THA. Discussion There is no evidence in the literature to support the effectiveness of MARS MRI to detect periacetabular osteolysis around cobalt chromium alloy metal-on-metal total hip arthroplasties. Osteolysis due to corrosion-related particles seems to be one of the primary modes of failure in modular MoM THA. Conclusions MRI is not a sensitive test to identify periacetabular osteolysis. The authors recommend CT for the screening of implants with this failure mode. Our study suggests that patients with a Birmingham modular MoM THA are at increased risk to develop acetabular osteolysis and should be carefully monitored for this failure mode.
    Archives of Orthopaedic and Trauma Surgery 05/2014; 134(7). DOI:10.1007/s00402-014-2005-9 · 1.60 Impact Factor
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    ABSTRACT: For hip resurfacing, this is the first biomechanical study to assess anterior and posterior femoral neck notching and femur flexion and extension. Forty-seven artificial femurs were implanted with the Birmingham Hip Resurfacing (BHR) using a range of notch sizes (0, 2, 5 mm), notch locations (superior, anterior, posterior), and femur orientations (neutral stance, flexion, extension). Implant preparation was done using imageless computer navigation, and mechanical tests measured stiffness and strength. For notch size and location, in neutral stance the unnotched group had 1.9 times greater strength than the 5-mm superior notch group (4539 vs. 2423 N, p=0.047), and the 5-mm anterior notch group had 1.6 times greater strength than the 5-mm superior notch group, yielding a borderline statistical difference (3988 vs. 2423 N, p=0.056). For femur orientation, in the presence of a 5-mm anterior notch, femurs in neutral stance had 2.2 times greater stiffness than femurs in 25-deg flexion (1542 vs. 696 N/mm, p=0.000). Similarly, in the presence of a 5-mm posterior notch, femurs in neutral stance had 2.8 times greater stiffness than femurs in 25-deg extension (1637 vs. 575 N/mm, p=0.000). No other statistical differences were noted. All femurs failed through the neck. The results have implications for BHR surgical techniques and recommended patient activities.
    IEEE transactions on bio-medical engineering 03/2013; 60(8). DOI:10.1109/TBME.2013.2251745 · 2.35 Impact Factor
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