Bone and muscle assessment in patients undergoing total hip arthroplasty using HU based analysis

Abstract

Total hip arthroplasty (THA) is performed with or without the use of bone cement. The lack of reliable clinical guidelines for deciding which one to implement has encouraged this approach of joint clinical and engineering with the following objectives: 1. Validate quadriceps muscles and femur bone atrophy by extracting the mineral density from Computer Tomographic (CT) images. 2. Validate computational processes based on 3-D modeling and Finite Element Methods (FEM). A clinical trial was started, where 36 volunteer patients underwent THA surgery for the first time: 18 receiving cemented implant and 18 receiving uncemented implant. The patients were CT scanned prior-, immediately after and 12 months post-surgery. The CT data are further processed to segment muscles and bones and to create 3D-models for the simulation and for calculating bone mineral density (BMD). Furthermore quadriceps muscle density Hounsfield (HU) based value is calculated from the segmented file on healthy and operated leg. These preliminary results indicate computational tools and methods that are able to quantitatively analyse patient's condition pre and post-surgery. The BMD and muscle density measurement in correlation with the fracture risk analysis display a potential method for eligibility to receive non-cemented implant; the preliminary results show that also elderly that according with current clinical evaluation receives a cemented implant are suitable for the non-cemented type. The risk for structural failure during THA surgery is estimated by calculating femoral bone fracture risk index (FRI) as a ratio between compressive stress during surgery and estimated failure stress on bone. The correlations with the BMD observations during the clinical trial will assess and validate this potential predictor tool.

Health technology assessment through Six Sigma Methodology to assess cemented and uncemented protheses in total hip arthroplasty

“…The decision-making process relating to the type of prosthesis has been much discussed in the literature, 41,[44][45][46][47] but different opinions on the subject remain.. The past objectives were to find differences between biomechanical parameters extracted from patients undergoing cemented and uncemented prosthesis THA.…”

“…The selection of the type of implant and the most appropriate method of fixation depend on the preferences of the surgeon (age, effectiveness and bone quality). 41,42 The prosthesis with cemented fixation, allows almost immediate ambulation, thus allowing fast rehabilitation. This solution is taken into consideration by patients over the age of 60 or those who have poor bone quality or severe forms of arthritis, although it is not very suitable for overweight or particularly active patients, as cement break-down could occur.…”

“…This type of intervention is recommended for younger, more active patients with better bone quality. 41…”

CT and MRI assessment and characterization using segmentation and 3D modeling techniques: applications to muscle, bone and brain

“…The preoperative BMD values calculated on the proximal femur (affected side) for all of the patients participating in the study are displayed in figure 5 . 25 From the same data set, figure 6 shows rectus femoris muscle density (affected side) for all the patients participating in the study. Finally figure 7 shows the fracture risk index calculated on different anatomical regions around the proximal femur for all patients.…”

Improving planning and post-operative assessment for Total Hip Arthroplasty

“…Both bone and muscle densities tend to be lower in the operated side which may be caused by the patient's shielding the involved side due to pain. 25 However, muscular strength tends to increase substantially on this side following the first post-operative year. 26 The functionality of the muscles is correlated with the muscle composition.…”