Arthritis in the knees is a debilitating condition that affects thousands of people every day.
Description of Knee Arthritis
Knee arthritis is any injury that involves damage to the cartilage on the end of the bones (the gristle that one sees on the end of a chicken bone is the cartilage). Once the cartilage in the knee is injured, there are no current treatments to restore it back to a healthy state. Thus, an injury to cartilage in the knee cannot heal naturally and any cartilage resurfacing technique does not restore normal cartilage surfaces.
Symptoms of knee arthritis include:
Knee osteoarthritis is the most common form of arthritis in the knees. Osteoarthritis of the knee is often caused by a traumatic injury from previous years. It is a slow, progressive degenerative disease in which the joint cartilage gradually wears away. This injury is typically seen in middle-aged and older people, but can sometimes affect younger patients, especially for patients who have had part of their meniscus removed for previous tears.
It is a common misconception that knee osteoarthritis is only seen as an end stage pathology prior to needing a knee replacement – the vast majority of knee arthritis we see were due to impact injuries – this knee arthritis is called traumatic arthritis. Post-traumatic arthritis can develop after an injury to the knee. This type of arthritis is similar to knee osteoarthritis and may develop years after a fracture, ligament tear, or meniscus injury. Many of these injuries are in localized areas of the knee, making potential treatments easier to perform and potentially more successful than arthritis in larger areas of the knee.
Treatment of Knee Arthritis
One of the most important aspects when treating knee arthritis is its location. Knee osteoarthritis on the femoral condyles (lower extremity of the femur) is much easier to treat than that of the trochlear groove (groove on top of the femur where the patella rests), patella (kneecap) or tibial plateaus (upper extremity of the tibia). The size of the lesion is an important factor as well – in general, smaller lesions are easier to treat than larger lesions.
Evaluation for a cartilage replacement surgery requires an assessment that includes: an analysis of the lesion’s size, whether there is a “kissing lesion” involving the cartilage surface on the opposite side of the defect, how much meniscus is present, any ligament instability, and the patient’s structural knee alignment. If the meniscus had a previous excision of a sizable portion – then there is a much lower chance that the cartilage replacement will be successful. This is due to the important cushioning role the menisci play in the knee. The meniscus serves as a shock absorber and cushions the tibia and femur from impact. Thus, for some types of knee arthritis, a concurrent meniscal transplant must be performed to restore the cushioning effect for the surfaces of the knee joint.
In addition, it is important to assess the alignment of the patient’s knee. In comparison with patients who have a normal alignment or knock-knee alignment, patients who are bowlegged (varus alignment) and have lesions is on the inside of the knee have a much lower chance that the cartilage replacement surgery will work successfully.
Our treatment method for knee arthritis includes microfracture for well-shouldered and smaller lesions,osteochondral autograft transplants of healthier cartilage from a lesser weight bearing area of the knee to the affected area for slightly larger areas and smaller areas where there may be small bone cysts, andfresh osteoarticular allografts for failed microfracture surgeries and larger lesions. We have performed autogenous cartilage implantation procedures in the past, but have found that the histological appearance, which is closely similar to microfractures, the high cost, and fact that the recovery time is much greater limits us in performing this procedure to very select circumstances.
In addition, it is important for the patient to have a thorough assessment of their overall health; their relative age, knee alignment, amount of joint space narrowing, size of the defect, remaining portion of the meniscus, smoking history as well as other medical factors such as diabetes or conditions which require the use of oral steroids are required to choose the best treatment for their specific symptoms of knee arthritis. With a complete and thorough evaluation, the chances of having an improved and longer lasting outcome increase and the symptoms of knee arthritis will decrease.
An essential part of treating arthritis in the knees is the post-operative rehabilitation program. Patients who undergo microfracture treatment and begin an immediate weight-bearing program have less successful results than those who are non-weight bearing for six weeks and for those who use a continuous passive motion machine for 6-8 hours each day. There are additional post-operative rehabilitation protocols that increase a patient’s chance for a successful outcome for each individual cartilage resurfacing procedure. Thus, patients must work diligently with their physical therapist to optimize their post-operative result.