The early days of the modern total hip arthroplasty (THA), in the 1960s and early 1970s, were primarily dominated by two different design philosophies. Sir John Charnley’s design was based on the “low friction” principle – using a monobloc femoral stem with a small head to articulate with a large polyethylene acetabular component to reduce volumetric wear(1). The McKee-Farrar prosthesis....