Cement strain measurement surrounding loose and well-fixed femoral component stems

Strain measurement within the cement surrounding stemmed total hip femoral components was accomplished using PMMA encapsulated and embedded strain gauges. Cement strain measurement associated with a well-bonded stem-cement interface and an unbonded stem-cement interface (i.e., loose prosthesis) was performed. The presence of a stem-cement bond was found to reduce proximal cement strain magnitudes while having little effect on distal cement strain magnitudes. The assurance of a stem-cement bond on only the proximal third of the interface was found to have an effect similar to that of a complete stem-cement bond. The results of this experimental investigation confirm the theoretical prediction that the stem-cement bond is important in maintaining the integrity of the cement mantle surrounding a stemmed femoral component.