Osteoarthritis (OA or degenerative arthritis) is the most common joint disorder known. Osteoarthritis is characterized by cartilage loss at the joint, and symptoms generally include pain and stiffness. The disease can affect all joints of the body, including the hip, shoulder, ankle, and spine, to name a few. One form of the disorder, osteoarthritis of the knee, is a common and rapidly growing problem amongst U.S. adults. Knee osteoarthritis often causes severe pain and is associated with loss of function leading to a diminished quality of life. Knee osteoarthritis can be defined by the thinning, softening, fissuring, fibrillation, and eventual loss, of cartilage covering the surface of the bones in the knee joint. In the early stages of the disease process, this loss of cartilage may cause minimal pain and often those afflicted are asymptomatic. Unfortunately, the natural history of knee OA usually is progressive, leading to the significant symptoms and problems already described.
The main goal of osteoarthritis treatments is to reduce or eliminate pain, and restore normal joint function. Both non-surgical and surgical treatments are currently available for this purpose, with the appropriate treatment being selected based in part on the stage and/or severity of the disease.
Non-surgical treatments for knee osteoarthritis include weight loss (for the overweight patient), activity modification (low impact exercise), quadriceps strengthening, patellar taping, analgesic and anti-inflammatory medications, injections, and with corticosteroid and/or viscosupplements. Typically, non-surgical treatments, usually involving pharmacological intervention such as the administration of non-steroidal anti-inflammatory drugs or injection of hyaluronic acid-based products, are initially administered to patients experiencing relatively less severe pain or joint complications. However, when non-surgical treatments prove ineffective, or for patients with severe pain or bone injury, surgical intervention is often necessary.
One type of surgical treatment focuses on unloading forces from the damaged joint. Another type of surgical treatment aims to replace, either partially or wholly, the damaged area of the joint. For example, one surgical treatment seeks to replace the damaged or worn cartilage by way of cartilage resurfacing or cartilage replacement. Other surgical treatments, such as high tibial osteotomy (HTO) or total knee arthroplasty (TKA), are often recommended for patients with severe pain associated with osteoarthritis, especially when other non-invasive options have failed. Both procedures have been shown to be effective in treating knee pain associated with osteoarthritis, at least in the short term.
These treatments are based on the popular theory within the medical community that knee pain results from bone-on-bone contact or inadequate cartilage cushioning. These conditions are believed to frequently result from the progression of osteoarthritis, which is measured in terms of narrowing of the joint space. Therefore, the severity of osteoarthritis is believed to be an indicator or precursor to joint pain. Most surgeons and medical practitioners thus base their treatments for pain relief on this theory. However, the severity of osteoarthritis, especially in the knee, has been found to correlate poorly with the incidence and magnitude of knee pain. Because of this, surgeons and medical practitioners have struggled to deliver consistent, reliable pain relief to patients, especially if preservation of the joint is desired.
One of the most popular treatments for knee OA today is a procedure generally referred to as arthroscopic knee surgery. This type of surgery is frequently used when the patient has associated mechanical symptoms (i.e., locking, clicking, catching, etc.) During an arthroscopic knee surgery, the doctor uses an arthroscope to see inside the knee joint and do repairs without major surgery. With the arthroscope, the doctor may see early arthritic changes of the articular cartilage and small tears in the meniscus. The tear may be repaired with sutures, staples, or other known tissue fixation devices. Other minor repairs to the cartilage may also be performed in this procedure.
However, it has been observed that patients with osteoarthritis continue to deteriorate and the disease worsens after an arthroscopic knee surgery. It has been observed, in fact, that a large proportion of the patients who undergo an arthroscopy of the knee report experiencing worsened pain approximately six months later, with many of these same patients eventually requiring a total knee replacement (TKR). Total knee replacement is a highly invasive, major surgery that is irreversible.
Accordingly, better treatment options are still needed for patients suffering from osteoarthritis to treat the pain and avoid a total joint replacement surgery. It would be particularly desirable to provide a surgical option that can be performed during an arthroscopic surgery as a preventative step to either stop, or at least delay, the progression of the osteoarthritis symptoms, whereby the surgical option can also alter the natural course of the disease.