In total hip arthroplasty, the procedural standard for the fixation of metallic acetabular shells is underreaming and impaction. Recently, concerns have arisen regarding achieving and maintaining secure ceramic liners when thin shells are deformed during normal insertion. Failure to achieve an adequate ceramic taper lock has been associated clinically with disassembly1 and liner fracture2. Additionally, this phenomenon has been hypothesized to be a possible cause of articular squeaking, leading to revision in a small number of patients3. This study evaluates the influence of shell deformation on the locking-mechanism integrity of contemporary modular acetabular designs that employ ceramic liners.