Head-neck modularity for total hip arthroplasty. Is it necessary?

Although modular head-neck combinations for femoral components are convenient and useful, theoretical concerns make them less attractive. In a consecutive series of 100 primary cementless total hip arthroplasties, the neck length chosen for the broach trial reduction was compared with the final neck length chosen after the actual femoral component had been impacted. In 19%, the neck length was changed after insertion of the femoral component. As a result, leg-length inequality or wastage of these femoral components would have resulted. For cementless femoral components, the ability to adjust neck length after component impaction remains important.