Femoral head modularity in total hip arthroplasty (THA) design emerged in the 1970’s as an alternative to monolithic stem designs to overcome the disadvantages of limited head size and offset availability. Through the use of tapers, modularity has evolved and includes the femoral neck and stem to provide off-the-shelf flexibility for customizing proximal and distal canal filling, preservation of soft tissue structures, biomechanical restoration of offset, version and leg length as well as accommodating difficult situations of femoral deformity and bone loss.