Knee Surgery Now Includes Partial and Total Joint Replacements

Oct 22, 2018 | Articles

Knee Surgery Now Includes Partial and Total Joint Replacements

While most of the remarkable procedures performed by the bone and joint specialists of today are of relatively recent origin, there is actually evidence of advanced orthopaedic intervention that dates back to the time of the Ancient Egyptians. Although a single isolated case, a mummy first unearthed in 1971 was subjected to a DNA test more than two decades later, at which time it was discovered to have a 23-centimetre long, orthopaedic screw made of iron, embedded in its knee. The surgery was less sophisticated than the joint replacements performed today and was designed to stabilise the joint rather than mobilising it. Nevertheless, the design of this 3 000-year-old screw suggests that early Egyptian physicians may have had a far better understanding of orthopaedic principles than was previously believed.

The largest joint in the body involves the articulation of three bones – the femur, the tibia, and the patella or kneecap. They are secured in position, while preserving their mobility, by a combination of muscles, tendons, ligaments, and cartilage. In practice, each of these components is vulnerable to damage due to injury or disease that could create the need for various types of knee surgery, and even partial or total joint replacements in some cases.

One of the most common injuries to this joint is a torn meniscus. It is a common injury among sportsmen and women that often occurs when squatting, heavy lifting, or pivoting suddenly, and is characterised by pain and swelling. The meniscus is actually a wedge-shaped piece of cartilage attached to the head of the tibia that acts as a shock absorber, protecting the bone surfaces from impact damage. Although the damage may be relatively minor, a procedure known as a meniscectomy involving the removal of the torn portion is indicated in some cases, even though it may be possible to perform a meniscus repair. Performed, arthroscopically, these minimally-invasive forms of knee surgery are highly effective and joint replacements should not be necessary.

The arthroscope is a narrow tube that relays a video image of the inside of a joint to a monitor screen or eyepiece via an illuminated fibre-optic cable. An adaptation of earlier endoscopic devices, it has done much to simplify the task of the orthopaedic surgeon. Inserted via a tiny incision, it acts first as a diagnostic aid but, if an opportunity for intervention is seen, the surgeon may proceed to perform one or two more keyhole incisions to provide access for instruments. While not always an option when performing joint replacements, other common types of knee surgery that may be performed using this minimally-invasive technique include repairs to the patellar or quadriceps tendon, and reconstruction of the anterior cruciate ligament (ACL).

Where, as in cases of osteoarthritis, the damage to the cartilage is too severe to be repaired, the only remaining option may be to replace the natural joint with a prosthetic one. If the cartilage on just one of the long bones is involved, a partial prosthesis will normally be adequate and can sometimes be undertaken arthroscopically. However, if the surfaces of both the femur and tibia are badly damaged, the only practical form of knee surgery remaining will be to provide suitable prosthetic replacements for the heads of both of the damaged bones.