Femoral head penetration, radiographic

The absolute amoimt of wear observed in a group of patients is going to depend on the time interval between radiographic examinations. Consequently, clinical researchers starting with Charnley have been interested in the linear wear rate (LWR), or the change in apparent femoral head penetration (P) over time (f) ... 

Patient Study Number Date of Index Radiograph Date of Follow-up Radiograph Femoral Head Penetration from Index Radiograph (mm) Femoral Head Penetration at Follow-up Radiograph (mm)... 

A key assumption of any femoral head penetration measurement is that the femoral head is seated into the deepest p)ortion of the acetabular comp)onent at each radiographic... 

The goal of using radiographic analysis techniques to measure wear in total hip arthroplasty has changed over time. Originally, they were used to correlate the amount of femoral head penetration with the incidence of periprosthetic osteolysis. This association is now well established and irrefutable. New bearing materials, such as... 

Methods have been proposed by Griffith et al. (1978) and Deavane et al (1995) to radiographically measure linear wear in UHMWPE acetabular cups of total hip replacements. The overall penetration of a femoral head (Tables 7.8 and 7.9) into a UHMWPE acetabular cup is a consequence of both creep and wear, where creep is predominantly observed for the first million loading cycles (Dowson, 1995). Atkinson et al (1980) estimated that the total UHMWPE residual compression due to creep in total hip replacements after x can be estimated by ... 

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