Abstract
Arthritis of the knee is a common painful condition. The knee joint is susceptible to the development of arthritis from various conditions that can damage the joint cartilage. Osteoarthritis is the most common form of arthritis that results in knee pain; rheumatoid arthritis and posttraumatic arthritis are also common causes of knee pain. Less-frequent causes of arthritisinduced knee pain include the collagen vascular diseases, infection, villonodular synovitis, and Lyme disease. Acute infectious arthritis is usually accompanied by significant systemic symptoms, including fever and malaise, and should be easily recognized.
Keywords
arthrtis knee, osteoarthritis, knee pain, rheumatoid arthritis, psoriatic arthritis, torn meniscus, septic arthritis, Lyme disease, villonodular synovitis, magnetic resonance imaging, intra-articular injection, diagnostic sonography, ultrasound guided injection
ICD-10 CODE M17.9
Keywords
arthrtis knee, osteoarthritis, knee pain, rheumatoid arthritis, psoriatic arthritis, torn meniscus, septic arthritis, Lyme disease, villonodular synovitis, magnetic resonance imaging, intra-articular injection, diagnostic sonography, ultrasound guided injection
ICD-10 CODE M17.9
The Clinical Syndrome
Arthritis of the knee is a common painful condition. The knee joint is susceptible to the development of arthritis from various conditions that can damage the joint cartilage. Osteoarthritis is the most common form of arthritis that results in knee pain; rheumatoid arthritis and posttraumatic arthritis are also common causes of knee pain. Less-frequent causes of arthritis-induced knee pain include the collagen vascular diseases, infection, villonodular synovitis, and Lyme disease. Acute infectious arthritis is usually accompanied by significant systemic symptoms, including fever and malaise, and should be easily recognized; it is treated with culture and antibiotics rather than injection therapy. Collagen vascular disease generally manifests as polyarthropathy rather than as monarthropathy limited to the knee joint, although knee pain secondary to collagen vascular disease responds exceedingly well to the treatment modalities described here.
Signs and Symptoms
Most patients with osteoarthritis or posttraumatic arthritis of the knee complain of pain localized around the knee and distal femur. Activity makes the pain worse, whereas rest and heat provide some relief. The pain is constant and is characterized as aching; it may interfere with sleep. Some patients complain of a grating or popping sensation with use of the joint, and crepitus may be present on the physical examination.
In addition to pain, patients often experience a gradual reduction in functional ability because of decreasing knee range of motion that makes simple everyday tasks such as walking, climbing stairs, and getting in and out of a car quite difficult ( Fig. 105.1 ). With continued disuse, muscle wasting may occur, and a frozen knee resulting from adhesive capsulitis may develop.
Testing
Plain radiographs, magnetic resonance imaging (MRI), and ultrasound imaging are indicated in all patients who present with knee pain ( Figs. 105.2, 105.3, and 105.4 ). Based on the patient’s clinical presentation, additional testing may be warranted, including a complete blood count, erythrocyte sedimentation rate, and antinuclear antibody testing. MRI and ultrasound imaging of the knee are also indicated if the diagnosis is in question, if an occult mass or tumor is suspected, or in the presence of trauma ( Fig. 105.5 ).
