Migration of the trial femoral head is a rarely occurring complication of total hip arthroplasty (THA) performed using the anterolateral approach (ALA). This migration of the trial femoral head under the rectus femoris is extremely risky because of the anatomical situation. Analyzing the morphological character of a case of migration may help us to avoid this risk. We analyzed the three-dimensional bone morphology using computed tomography (CT) scan images to investigate the physiological characteristics of five migration cases.Introduction
Objective
Hydroxyapatite and poly-L-lactide (HA/PLLA) composites are osteoconductive and biodegradable. They have already been used clinically to treat fractured bones by inducing osteosynthesis and serving as the bone filling material. During revision of total hip arthroplasty, we have grafted bone onto the bone defect and covered it with an HA/PLLA mesh instead of using a metal mesh on the non-load bearing portion of the cup (Figure 1). However, whether the interface between the HA/PLLA and the titanium alloy cup was stable remains unclear. The purpose of this study was to determine and compare the histological osteoconductivity and osteoinductivity of HA/PLLA and titanium alloy.Introduction
Objectives
The initial stress distribution in the femur after total hip arthroplasty (THA) influences the remodeling of the bone and the clinical results. We conducted thermoelastic stress analysis to evaluate the surface stress distribution in femurs after THA in vitro and elucidated the changes in the stress distribution that were due to the stem design. Using this method, we can analyze the change in the sum of the principal stresses on the basis of the changes in temperature at the bone surface and visualize the change three-dimensionally. We compared the thermoelastic stress analysis results with the clinical results of specially shaped stems that have two flanges, one anterior and one posterior.Introduction
Objectives
We have previously shown that joint distraction and movement with a hinged external fixation device for 12 weeks was useful for repairing a large articular cartilage defect in a rabbit model. We have now investigated the results after six months and one year. The device was applied to 16 rabbits who underwent resection of the articular cartilage and subchondral bone from the entire tibial plateau. In group A (nine rabbits) the device was applied for six months. In group B (seven rabbits) it was in place for six months, after which it was removed and the animals were allowed to move freely for an additional six months. The cartilage remained sound in all rabbits. The areas of type II collagen-positive staining and repaired soft tissue were larger in group B than in group A. These findings provide evidence of long-term persistence of repaired cartilage with this technique and that weight-bearing has a positive effect on the quality of the cartilage.
