Arthritis is a debilitating condition that affects thousands of people every day. Symptoms of knee arthritis include knee pain, soreness and a dull, constant ache in the knee joint. Osteoarthritis of the knee is the most common form of knee arthritis. It is a slow, progressive degenerative disease in which the joint cartilage gradually wears away. It most often affects middle-aged and older people, but can affect younger patients, especially those who have had part of their menisci taken out for tears.
Arthritis, in essence, is any injury which 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 cartilage is injured, there is no current treatment which can restore it back to normal. Thus, an injury to cartilage does not heal.
While most people think of osteoarthritis of the knee as the end stage pathology that one has prior to needing a knee replacement, the vast majority of localized areas of knee arthritis we see are due to injuries, hence this is called traumatic arthritis. Post-traumatic arthritis can develop after an injury to the knee. This type of arthritis is similar to osteoarthritis and may develop years after a fracture, ligament tear, or meniscus injury. Many of these injuries are in localized areas of the knee and can be more easily treated.
One of the most important aspects about the treatment of localized knee arthritis is the location. Osteoarthritis of the knee on the femoral condyles is much easier to treat than that of the trochlear groove, patella or tibial plateaus. The size of the lesion is an important factor as well and in general, smaller lesions do better than larger lesions.
Any workup for potential treatment for a cartilage replacement technique must include an assessment 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 remains,an assessment of any ligament instability, and the patient’s knee alignment. If the meniscus had a previous excision of a sizable portion, then there is a much lower likelihood that the cartilage replacement procedure will work. This is because the meniscus has an important cushioning affect, acting as a shock absorber and cushioning the tibia and femur from impact.
Thus, for some treatments of localized knee arthritis, a concurrent meniscal transplant must be performed. In addition, it is important to assess the alignment. If a patient is bowlegged (varus alignment) and the lesion is on the inside of the knee, there is a much lower chance the replacement procedure will work compared to a patient with normal alignment or knock-knee alignment (valgus).
Our treatment method for localized knee arthritis includes microfracture for well shouldered and smaller lesions, autogenous osteochondral transplants of more normal cartilage from a lesser weight bearing area of the knee to the affected area, and fresh osteoarticular allografts. We have performed autogenous cartilage implantation procedures in the past, but have found that the downtime involved with these, the histological appearance which is essentially similar to microfractures, the high cost, and fact that patients take much longer to return to activities and work limits us in performing this procedure to very select circumstances.
It is important for the patient to have a thorough assessment of their overall health, relative age, alignment, amount of joint space narrowing, size of the defect, remaining portion of the meniscus, smoking history as well as other medical factors, in order to choose the best treatment for their symptomatic localized area of arthritis. With a complete and thorough workup, the chances of having an improved and longer lasting outcome increase and the symptoms of knee arthritis will decrease.
An absolutely essential part of treatment for localized areas of knee arthritis is the postoperative rehabilitation program. Patients who undergo microfracture and begin an immediate weight bearing program have much poorer 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 other similar postoperative rehabilitation protocols, which must be followed for treatment of localized knee arthritis, which increases a patient’s chance for a successful outcome. Thus, working with ones physical therapist can help to optimize ones postoperative result.
Osteoarthritis of the knee is often caused by a traumatic injury from years prior. This ultimately can cause localized knee arthritis.
