Articular cartilage covers the ends of each bone and allows a smooth, fluid, pain free motion of the knee joint. The cartilage is an extremely important component of a healthy knee and when damaged a patient will suffer from pain and swelling during activities. If the damage progresses, it will eventually lead to a complete loss of cartilage down to the bone, commonly known as osteoarthritis. A chondral defect, or damage to the articular cartilage, may require surgical treatment if a patient has persistent symptoms despite appropriate conservative care.
In the office, cartilage injuries are diagnosed using a history and physical exam. Plain x-rays will be used to assess the amount of cartilage remaining. In most cases an MRI will be used to evaluate the cartilage surfaces and identify a defect. In addition, the alternate structures in the knee such as the meniscus and ligaments are reviewed.
Knee cartilage repair depends on a number of factors including the size, depth and location of the torn knee cartilage, associated knee injuries, patient’s activity level and patient’s age and weight. Some cartilage injuries can be treated non-operatively, but a surgical knee cartilage treatment is commonly needed in cases with a focal cartilage defect.
The most common knee cartilage repair procedures are chondroplasty and Microfracture. Dr. Waterman will choose the appropriate treatment based on each patient’s torn knee cartilage injury. Listed below are common techniques used by Dr.Waterman:
- Chondroplasty: During this procedure, Dr.Waterman will trim away the damaged area of cartilage to alleviate the troublesome pain and swelling using an arthroscopic approach. This knee cartilage treatment is typically reserved for patients who do not have full thickness defects, or no bone to bone rubbing.
- Microfracture: During this procedure, Dr.Waterman will utilize a small pick to make holes in the defect’s bony surface. The holes allow the flow of marrow and stem cells which form a clot over the defect, eventually leading to a covering of a fibrocartilage layer. This technique is typically reserved for patients who have a full thickness loss of cartilage, or bone to bone rubbing.
- OATs: There are two types of OATs procedures- osteochondral autograft transfer and osteonchondral allograft transplantation. An autograft requires tissue to be harvested from the patient while an allograft requires a donor tissue from a tissue bank. In an autograft OATs procedure, small plugs of cartilage and bone are removed from the healthy portion of a patient’s knee and transferred to the damaged area. In an allograft OATs procedure, the cartilage and bone plugs are harvested from a donor and transplanted to the damaged area.
- Autologous cartiage implantation (ACI): ACI is a two stage procedure where a biopsy of healthy cartilage is first removed from the knee. Cartilage cells are harvested from the biopsy tissue, expand in a lab, and the replanted in the patients knee during a second surgery to facilitate growth of new cartilage surfaces.
Recovery and Rehabilitation after Articular Cartilage Defects Surgery
Dr. Waterman and his team will provide a detailed physical therapy program for patients following a knee cartilage treatment. Post-operative management is unique for each patient and depends on the specific knee cartilage repair performed and the severity of the torn knee cartilage. Patients who underwent chondroplasty are typically instructed to use crutches for a few days and allowed tolerated weight bearing with full range of motion. Patients who underwent Microfracture, ACI or an OATs procedure are placed in a brace and weight bearing is protected for approximately six to eight weeks. Following surgery, a continuous passive motion (CPM) machine is generally used in these patients for six weeks. Typical time frame for maximum improvement following cartilage replacement is often six to twelve months.