Technology is Extending the Scope of Hip and Joint Replacement Specialists
The very existence of surgeons who have become specialists in the replacement of the hip and various other joints with a prosthetic implant is a testament to the vast extent by which orthopaedic surgery has progressed since the 18th century and the days of the so-called bonesetters. No longer confined to reducing fractures and attempts to straighten the misshapen spinal columns of young children, much of the theatre time of a modern orthopaedic surgeon is likely to be spent on restoring smooth, pain-free articulation for patients affected by diseased or damaged hips, shoulders, knees, elbows, and ankles.
Known as arthroplasty, apart from the need to repair accidental injuries, the most common reason for performing this type of procedure is to rectify the damage caused by osteoarthritis. Where the ball and socket joint in the hip is affected, specialists may perform either a total or partial replacement to relieve pain and restore movement, depending upon the extent of the damage.
The surface of the socket, in this case, a cup-shaped recess called the acetabulum, and that of the ball, in this case, the head of the femur, is covered by a protective coating of cartilage. This allows the two surfaces to move smoothly against one another while walking, running, or bending. Should one or both of these cartilage layers become damaged, they will no longer articulate smoothly. The resulting friction causes further wear and tear to the affected surfaces, leading to pain and, as the severity of the damage increases, often to loss of mobility.
Unlike those performed by today’s specialists, the early attempts at hip and joint replacement were frustrated by the lack of suitable materials from which to fashion the implanted components. The subsequent development of stronger and more biocompatible materials, in combination with successive refinements to the surgical procedures used to insert the implants, has served to position total arthroplasty and partial or hemiarthroplasty as the most successful interventions in the history of orthopaedics.
Joint excision surgery was being performed regularly as early as the 17th century, as a means to avoid amputations among injured naval and military personnel. However, only in 1891, with the implantation of an ivory prosthesis, was an actual hip joint replacement seen to be possible. Although it failed quite quickly, orthopaedic specialists eventually developed less fragile materials and improved techniques, so by the 1920s, patients undergoing this type of implantation surgery were showing fairly consistent improvements in their mobility.
In addition to the use of various metal-on-metal, metal-on polypropylene, ceramic-on-metal, and ceramic-on-ceramic combinations to create the implants, the surgical procedure has been made far less invasive thanks to the introduction of a technique known as arthroscopy. A modified endoscope inserted into the joint via a keyhole incision offers live viewing of any damage to the bone and connective tissues and, if indicated, the specialist may proceed with the replacement of a hip, knee, or other joint using instruments introduced through a second keyhole incision. Arthroscopic procedures limit the risk of infection and reduce recovery time.
There are some exciting times ahead for orthopaedic surgeons. Surgical machines already enable more precise positioning of prostheses, while research into the growth of natural cartilage and bone from stem cells has been showing some very promising results.