We report a case of late dissociation of a one-piece metal-backed acetabular component, associated with a prolific soft-tissue reaction to the polyethylene debris. The polyethylene liner was not visible on the radiographs. The metal-backed shell could not be removed because of bone ingrowth. We recommend that modular systems be utilised in cementless arthroplasty of the hip and that radiographi...

The trait of the ball mill is chaotic in nature due its complex dynamics associated during grinding. Grinding in ball mill generates high-intensity vibration and is too complex on account dependency of multiple variables. In this paper, the vibration signal is acquired using a low power ZigBee based three axes wireless MEMS accelerometer sensor mounted onto the mill shell. Firstly, the exact fr...

A nonlinear, finite-element, model is used to examine the biodynamic impact response to helmeted and unhelmeted headforms having human response characteristics. The human response headform is modeled as a spherical brain of nearly incompressible material, a covering of linear elastic dura, a linear elastic spherical skull, and a layer of nonlinear scalp material. The helmet system is modeled as...

The ABG I cementless hip prosthesis has demonstrated unacceptably high rates of wear and osteolysis in our patients. We performed a retrospective study of 97 hips implanted between 1992 and 1998. Radiographic analysis revealed high rates of wear of the polyethylene liner with marked peri-acetabular osteolysis. Clinical examination indicated that many of these patients were initially asymptomati...

A high incidence of acetabular osteolysis (43%), associated with osteolytic lesions in the proximal femur (22.6%) and leading to a high revision rate, was experienced with the Omnifit total hip prosthesis. We reviewed the clinical and radiological results with 429 Omnifit total hips in 356 patients after a mean follow-up of 60 months. Time to revision and wear of the polyethylene liner with dif...

The parameters of mill load (ML) not only represent the load of the ball mill, but also determine the grinding production ratio (GPR) of the grinding process. In this paper, a novel soft sensor approach based on multi-spectral segments partial least square (PLS) model and on-line adaptive weighted fusion algorithm is proposed to estimate the ML parameters. At first, frequency spectrums of the s...

We report complications from the use of modular components in 20 hip replacements in 18 patients. Fifteen complications (in 13 patients) were related to failure of a modular interface after operation. Femoral head detachment from its trunnion was seen in 6 hips from trauma (3), reduction of a dislocation (2), and normal activity (1). In one case the base of the trunnion fractured below an extra...

Backside wear due to micromotion and poor conformity between the liner and its titanium alloy shell may contribute to the high rates of retroacetabular osteolysis and consequent aseptic loosening. The purpose of our study was to understand the wear process on the backside of polyethylene liners from two acetabular cup systems, whose locking mechanism is based on a press-fit cone in combination ...