Charnley's 1960 paper uses cadaveric friction measurements on human knee and ankle joints to challenge the prevailing hydrodynamic theory of joint lubrication. It asks: what is the actual mechanism of joint lubrication, and what does that mean for how we build artificial joints? The answer drives his first clinical series of low-friction hip arthroplasty.
The critical insight here is not just that cartilage is slippery — it is that BOTH bearing surfaces must be intrinsically low-friction for an artificial joint to work. A polished metal head relying on synovial fluid for lubrication will fail because synovial fluid cannot maintain a hydrodynamic film under physiologic loads.
When you select bearing surfaces for total hip arthroplasty, this paper is the reason the acetabular component material matters as much as the femoral head. High friction at the interface generates torque that twists the implant loose from bone. Reducing µ reduces fixation failure.
When you perform hemiarthroplasty, this paper explains why the indication matters: intact acetabular cartilage (fresh fracture) provides low-friction articulation with the prosthesis, while eburnated bone (osteoarthritis) does not. Choosing hemiarthroplasty for end-stage osteoarthritis invites the exact high-friction scenario Charnley demonstrated in the lab.
Although PTFE was abandoned within a decade due to catastrophic wear debris, the principle Charnley established here. Low-friction arthroplasty requiring a purpose-designed acetabular liner. Led directly to ultra-high-molecular-weight polyethylene and the Charnley total hip, the most replicated implant in surgical history.
Charnley's 1960 paper uses cadaveric friction measurements on human knee and ankle joints to challenge the prevailing hydrodynamic theory of joint lubrication. It asks: what is the actual mechanism of joint lubrication, and what does that mean for how we build artificial joints? The answer drives his first clinical series of low-friction hip arthroplasty.
The critical insight here is not just that cartilage is slippery — it is that BOTH bearing surfaces must be intrinsically low-friction for an artificial joint to work. A polished metal head relying on synovial fluid for lubrication will fail because synovial fluid cannot maintain a hydrodynamic film under physiologic loads.
When you select bearing surfaces for total hip arthroplasty, this paper is the reason the acetabular component material matters as much as the femoral head. High friction at the interface generates torque that twists the implant loose from bone. Reducing µ reduces fixation failure.
When you perform hemiarthroplasty, this paper explains why the indication matters: intact acetabular cartilage (fresh fracture) provides low-friction articulation with the prosthesis, while eburnated bone (osteoarthritis) does not. Choosing hemiarthroplasty for end-stage osteoarthritis invites the exact high-friction scenario Charnley demonstrated in the lab.
Although PTFE was abandoned within a decade due to catastrophic wear debris, the principle Charnley established here. Low-friction arthroplasty requiring a purpose-designed acetabular liner. Led directly to ultra-high-molecular-weight polyethylene and the Charnley total hip, the most replicated implant in surgical history.