How Long Does a Knee Replacement Last?
Barring accidents, most patients who undergo a knee replacement today can look forward to many years of invaluable aid from their prosthetic joint. While the skill of the attending orthopaedic surgeon plays a crucial role in the success of this procedure, its longevity is also the result of decades of advances in technique and materials science. Running, walking and even standing place considerable strain on the bones, even in a healthy joint. Thus, any material which is to be used as a substitute for bone needs to be equally robust. It must also be biocompatible.
Walking back in History
The first attempt at this procedure was by a German surgeon during the 1860s. To perform his patient’s knee replacement, he inserted a hinged joint made of iron. However, while the implantation was successful, its benefits were short-lived. Short-term failures continued to plague early efforts at transplantation, and it took a further one hundred years before the problem was resolved. In the late 1960s, a British surgeon named John Charnley utilised a metal-on-polythene prosthesis to perform the first successful total knee arthroplasty.
Since then, new materials like ceramics and titanium, changes to the geometry of prosthetic joints and alternative fixation methods have continued to improve performance and longevity. Today, knee replacement is widely accepted as one of the most successful interventions devised by orthopaedic surgeons. With care, most patients who receive one of these prosthetic joints can expect it to continue functioning for as long as fifteen to twenty-five years. Nevertheless, ultimately, a significant portion of the responsibility for this type of surgery’s short- and long-term success rests with the patient.
Resuming Business as Usual
Many patients are surprised when their surgeon encourages them to stand and walk soon after their operation. However, this is not an invitation to resume business as usual. A knee replacement is a traumatic procedure. It involves the dissection of soft tissue, blood loss, the removal of damaged bone and the attachment or embedding of the prosthetic components. Naturally, the surgery will result in some swelling and discomfort, so during those early attempts at movement, most patients are likely to require some support from a cane or walking aid.
Rather than exposing the entire joint, some surgeons now favour a minimally-invasive procedure. They make three or more minor incisions to provide portals for their instruments and use a miniature video camera to monitor their actions. However, although an arthroscopic knee replacement will require less recovery time than open surgery, patients still need to exercise caution. Well-honed skills, experience, and improved prostheses have made the need to perform revision surgery due to a primary surgical failure rare. In practice, when a revision is necessary, it is usually because the patient has not adhered to the advice concerning the correct post-operative care.
The Next Steps
The secret is to make haste slowly. While building up the muscles that support the newly replaced joint is essential, this must be a gradual process. So, for example, patients should first avoid stairs and stick to the mild exercise programme prescribed by the physiotherapist.
If you think you may require a knee replacement, you might want to complete these multiple-choice questions.