Total Hip Arthroplasty (THA) is a major surgical procedure that replaces the damaged hip joint (femoral head and acetabulum) with prosthetic components to restore movement and relieve severe pain caused by conditions like arthritis. This common and highly successful modern operation has a complex developmental history, marked by many decades of trial and error before a durable solution was achieved.
Early Attempts and Precursors
The earliest recorded attempts to replace portions of the hip joint date back to the late 19th century (around 1891). These initial efforts involved using non-biological materials such as ivory to replace the femoral head, often secured with screws or plaster. These early implants, while innovative, were not successful in the long term due to the body’s inability to integrate them and the materials’ failure under the constant load of the hip joint.
Surgeons later experimented with interpositional arthroplasty, placing various materials between damaged bones to create a new gliding surface. This involved substances like pig bladder submucosa, metal foil, or glass, but these methods frequently led to painful, unstable joints or material failure, such as the shattering of glass molds. Another common technique, resection arthroplasty, involved removing the diseased bone entirely to relieve pain, but this often resulted in a flail, unstable leg. These procedures highlighted the need for a solution that could both replace the joint and remain securely fixed to the bone without causing a rejection response.
The Pivotal Breakthrough
The first successful, standardized, and long-lasting total hip replacement procedure was performed in the United Kingdom by Sir John Charnley in the early 1960s. After earlier failures with materials like Teflon, which wore out rapidly, Charnley pioneered what he called the “low-friction arthroplasty” system. This breakthrough was based on three synchronized innovations that addressed the issues of wear and fixation.
Charnley’s design used a small, polished stainless steel femoral head articulating against a socket made of ultra-high-molecular-weight polyethylene. The smaller ball size was a deliberate choice to decrease the friction and resulting wear debris between the moving surfaces. The most transformative element was the use of polymethyl methacrylate (PMMA) bone cement, a material adapted from dentistry, to securely grout both the femoral stem and the acetabular cup into the bone. This cemented fixation provided immediate stability, separating Charnley’s method from all prior temporary measures. The procedure, first performed successfully in November 1962, rapidly became the gold standard for treating severe hip arthritis.
Evolution of Modern Materials and Techniques
Following Charnley’s innovation, subsequent decades focused on improving the longevity and wear resistance of the original components. A major development was the introduction of uncemented or press-fit fixation, which uses porous or textured implant surfaces. This allows the patient’s own bone tissue to grow directly onto the implant, providing a biological, long-term anchor, particularly beneficial for younger, more active patients. These cementless stems are often coated with materials like hydroxyapatite to promote this bone ingrowth.
Refinements in bearing surfaces have been substantial. Engineers developed highly cross-linked polyethylene, which significantly reduced the amount of wear debris compared to the original plastic, thereby minimizing the body’s inflammatory response that can cause implant loosening. Alternative bearing combinations, such as ceramic-on-ceramic and metal-on-metal systems, were also introduced to address wear concerns. Furthermore, surgical approaches have advanced, with minimally invasive and computer-assisted techniques offering more precise implant placement and potentially faster patient recovery.
Current Scope and Success
Total hip arthroplasty is now one of the most successful and commonly performed procedures in orthopedic surgery globally. Hundreds of thousands of these operations are performed annually in the United States alone. The success rate is extremely high, with approximately 90% of patients reporting significant improvement in pain and mobility within five years of surgery. Modern implants have excellent long-term durability, with many studies showing a survival rate of approximately 90% or greater at 15 years post-implantation. This longevity and consistency of outcome have profoundly improved the quality of life for millions of individuals suffering from debilitating hip joint disease.