Objectives. Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. Methods. In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters. Results. There was no significant difference between the two bearing types with both genders combined. However, dividing patients by THA bearing and gender, women with MoM bearings had the highest Ktrans values, exceeding those of women with MoP bearings (0.067 min. −1. versus 0.053 min. −1. ; p-value < 0.05) and men with MoM bearings (0.067 min. −1. versus 0.034 min. −1. ; p-value < 0.001). Considering only the men, patients with MoM bearings had lower Ktrans than those with MoP bearings (0.034 min. −1. versus 0.046 min. −1. ; p < 0.05). Conclusion. DCE-MRI is feasible to perform in tissues surrounding THA. Females with MoM THA show high Ktrans values in DCE-MRI, suggesting altered tissue perfusion kinematics which may reflect relatively greater inflammation. Cite this article: Dr P. E. Beaule. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot stud. Bone Joint Res 2016;5:73–79. DOI: 10.1302/2046-3758.53.2000572

Introduction and Objectives: The aim of this study is to characterize cartilage perfusion and determine the degree of cartilage lesion using MRI during the injection of a paramagnetic contrast medium in pharmacokinetic models with the aim of obtaining the corresponding dynamic parameters (permeability and fraction of extracellular extravascular volume). Materials and Methods: We included 20 patients with patellar cartilage alterations in this study and proceeded to carry out their clinical assessment. The patients were randomly chosen for the glucosamine sulphate group or the placebo group. Both groups began treatment immediately after the first MR and continued uninterrupted treatment until the second exam 6 months later. Results: in patients treated with glucosamine sulphate significant differences were found between pain reported by the patients and their functional score results. There are also statistically significant differences in the Ktrans parameter, with higher values in the group that received glucosamine sulphate, both for arthritis and for chondromalacia. Discussion and Conclusions: Glucosamine sulphate has an effect on the vascular properties and metabolism of cartilage. There was a strong relationship between treatment and increased cartilage vascular permeability (Ktrans): This makes it possible for us to suggest that the measurement of capillary permeability could be a surrogate marker for determining the effect of 6 months treatment with glucosamine sulphate on the metabolism of degenerated cartilage