Evaluation of the effect of custom burr holes on a surgeon's sense of screw fixation in revision porous metal cups.

BACKGROUND/AIMS: It is common practice to burr custom holes in revision porous metal cups for screw insertion. The objective of this study was to determine how different hole types affect a surgeon's sense of screw fixation.

METHODS: Porous revision cups were prepared with pre-drilled and custom burred holes. Cups were held in place adjacent to synthetic bone material of varying density. Surgeons inserted screws through the different holes and materials. Surgeon subjective rating, compression, and torque was recorded.

RESULTS: The torque achieved was greater ( p  = 0.002) for screws through custom holes than pre-fabricated holes in low and medium density material, with no difference for high density. Peak compression was greater ( p  = 0.026) through the pre-fabricated holes only in high density material.

CONCLUSION: Use of burred holes affects the torque generated, and may decrease the amount of cup-acetabulum compression achieved.