Recently, an evidence-based study reported that arthroscopy was no more effective than physical therapy and medication for patients with osteoarthritis (OA) of the knee. How do you treat patients who present with moderate OA of the knee, and do you see a role for arthroscopic débridement in treating knee OA?
Frederick M. Azar, MD
Before considering any kind of surgical procedure for OA of the knee, I typically exhaust all the nonsurgical treatment options—activity modification, bracing, physical therapy, nonsteroidal anti-inflammatory drugs (NSAIDs), neutriceuticals, cortisone injections, and viscosupplementation (hyaluronic acid).
Frederick M. Azar, MD
J. Richard Steadman, MD
The protocol we use is designed to address the pain generators in the knee, but specific and correct rehabilitation is needed to maintain the gains made at surgery. Nonsurgical treatment of symptomatic degenerative arthritis is the first step in management. This includes activity modification, physical therapy, oral anti-inflammatories, and injectables such as steroids and viscosupplementation. Bracing is also considered in patients with varus or valgus alignment.
If nonsurgical management fails, arthroscopic surgery is the next step in our management plan. In our experience, painful symptoms decrease about 70 percent of the time if arthroscopic surgery is used to treat several crucial conditions and is followed by rehabilitation to maintain the gains obtained during surgery. Many conditions can produce pain in the degenerative knee. These include joint capsule stiffness, synovitis, loose bodies, meniscus tears, closed spaces due to compartmentalization or old adhesions, chondral defects, or flaps.
J. Richard Steadman, MD
The first step is to expand the joint using insufflation. The severely degenerative knee has diminished joint volume (60 mL to 90 mL, compared to the 180 mL in a normal knee). If the patient has never had knee arthroscopy before, the meniscus may be causing pain, so we always trim a meniscus tear to a stable rim. Retaining the meniscus rim and surface area coverage is essential, even in the chronic knee.
The synovium is often inflamed and becomes hypertrophic. Using a thermal ablation device on a low-intensity setting, we brush the surface to remove the inflamed portion of the synovium. If the synovium is dense, we use a higher-intensity setting. The goal is to remove the inflamed, hypertrophic synovium, which is a pain generator. Emphasis should be placed on the area adjacent to chondral damage—never directly to the chondral surface. Infrapatellar plica and suprapatellar plica are also removed.
Normally, no bridging scar tissue is found in the anterior interval—the space between the infrapatellar fat pad and patellar tendon anteriorly, and the anterior border of the tibia and the transverse meniscal ligament (anterior intermeniscal ligament) posteriorly. Scarring, however, is commonly found in the degenerative knee or the knee that has had previous surgery. For proper joint kinematics, the anterior interval needs to be opened by releasing the area just anterior to the intermeniscal ligament. The release is done from medial to lateral, just anterior to the peripheral rim of the anterior horn of each meniscus. The release can be performed with either electrocautery or a thermal ablation device.
Chondroplasty is performed as needed, and loose bodies are removed. Anterior osteophytes often block full knee extension, so they are removed with a burr or shaver. In the process of removing osteophytes, inflammatory elements (bone marrow) enter the joint. Therefore, a drain is recommended for several hours after the surgery to remove the marrow elements released by the osteophytectomy.
The principal goals of the rehabilitation program include the maintenance of joint volume and the prevention of scar reformation while preserving joint mobility. Regaining strength is a secondary goal. The rehabilitation program excludes exercises that elicit significant pain, and postoperative regimens are specifically tailored to each patient.
Jesse C. DeLee, MD
The San Antonio Orthopaedic Group, LLP
Patients with “moderate arthritis” of the knee have the following radiographic findings: marginal osteophytes; joint space narrowing, as demonstrated on weight-bearing AP and 30º PA radiographs; and sclerosis and/or deformity of bone contour in the involved compartment. The radiographs may also show that the affected knee has mild (less than 5º) varus or valgus malalignment when compared with the opposite knee.
These conditions correspond to the Kellgren-Lawrence scale Grades 2 and 3 (although the description of these grades is highly subjective and does not appear to be have been validated). Magnetic resonance images of many of these patients reveal degenerative meniscus tears that are not the cause of their symptoms.
Patients older than 50 years of age with the aforementioned radiographic findings, systematic joint disease, previous surgery, or increased pain with weight bearing (indicating chondral damage), but no mechanical symptoms or history of trauma, would not be candidates for arthroscopic meniscectomy. Treatment for these patients includes the following:
- physical therapy to restore full range of motion, including extension and quadriceps strengthening
- over-the-counter NSAIDs (if there is no contraindication)
- activity modification
- perhaps one steroid injection every 9 to 12 months
I occasionally offer viscosupplementation injections. If the patient has mild alignment abnormalities, I will recommend shoe modifications.