Rheumatoid arthritis invades any movable joint. It presents with pain (aggravated by activity), swelling and tenderness. Typical joint involvement is mostly: hands and wrists, feet and ankles, elbows, shoulders, knees, necks, and hips, mostly in a symmetrical distribution, and initially there may be only one pair of joints. Almost all patients with rheumatoid arthritis have involvement of the hand and wrist joints. These joints are the first to be involved and are the site of characteristic deformities in the late stages. A typical early feature is the pyknotic appearance of the proximal interphalangeal joint (PIP) due to swelling, often accompanied by a metacarpophalangeal joint
(MCP) symmetrical swelling, especially in the II and III metacarpophalangeal joints is very common, while the distal interphalangeal joint (DIP)
The distal interphalangeal joint (DIP) is rarely involved. Soft tissue laxity can produce ulnar deviation of the fingers, often accompanied by palmar subluxation of the proximal phalanges; ulnar deviation of the metacarpophalangeal joints is often combined with radial deviation of the radial metacarpophalangeal joints, resulting in a “zigzag” deformation of the hand; in advanced patients, due to hyperextension of the PIP and flexion of the distal interphalangeal joints, a “swan In advanced patients, “swan neck” deformity may occur due to PIP hyperextension and distal interphalangeal joint flexion. These changes will result in a loss of hand strength. Wrist involvement is particularly common in Chinese rheumatoid arthritis, and painless swelling of the ulnar styloid process is one of the early signs of rheumatoid arthritis. Acute synovitis manifests as cystic soft tissue swelling on the dorsal side of the wrist. Synovial thickening and sheathing on the palmar side may compress the median nerve under the transverse ligament, causing “carpal tunnel syndrome”. It may also be accompanied by atrophy of the greater interphalangeal muscle. In advanced stages, the wrist becomes immobile due to fibrous or bony ankylosis of the radial carpal, intercarpal, and/or carpometacarpal joints, and the involvement of the distal radial ulnar joint often causes extreme impairment of anterior and posterior rotation. Foot and ankle Arthritis of the foot is common and may even precede lesions of the hand and wrist, but the ankle is rare in early and mild cases. Synovitis of the metatarsophalangeal joint (MTP) is most common, and the interphalangeal joint is rarely involved. Swelling and subluxation of the metatarsophalangeal joint cause pressure pain on both sides of the toe, metatarsal pain, metatarsal head subluxation, bunion, lateral toe deviation and claw-like foot deformity. In early rheumatoid arthritis, the metatarsophalangeal joint is often the first to show erosive changes, and radiological examination of the 4th and 5th
The erosive changes of the 4th and 5th metatarsophalangeal joints are particularly sensitive. Elbow In the early stages of the disease, flexion contracture due to hyperplastic synovitis of the elbow can be seen, and a mass can be formed behind the lateral epicondyle of the humerus, proximal to the radial head, and the pars plana sulcus is often flooded with hypertrophic synovium. 4. Shoulder Involvement of the shoulder joint is common, but usually not in the early stages. The glenohumeral and acromioclavicular joints are most likely to be involved, with typical signs being limitation of motion and painful pressure below and around the external rostral process, and rupture of the joint capsule and subluxation of the humerus. About 25% of patients with early rheumatoid arthritis have cervical spine involvement, and as the disease progresses, symptoms eventually appear in 60% to 70% of patients. Neck pain and stiffness are common in rheumatoid arthritis, often invading the first and second cervical vertebrae. Progressive bone erosion can cause subluxation of the atlantoaxial joint, resulting in neurological symptoms due to crural compression, as well as torsion and compression of the vertebral artery, resulting in inadequate blood supply to the basilar artery, resulting in a range of clinical symptoms: abnormal limb movement, sphincter dysfunction, ataxia, nystagmus, and Swallowing difficulties, and can cause pain from the occiput to the scapula. 6, knee The knee is one of the most commonly involved and most disabling joints, with approximately l0% to 15% of patients with rheumatoid arthritis having the knee as the first manifestation. Hypertrophy and effusion of the synovial membrane are common, and clinical symptoms include joint stiffness, pain, difficulty walking and sitting, and getting up. Atrophy of the quadriceps muscle may occur several weeks after the knee lesion and rapidly affect knee extension function. Late complications include flexion contracture, valgus deformity, and ligament instability of varying degrees. The fluid accumulation in the knee cavity may increase the pressure in the cavity during knee flexion, at which time the fluid is squeezed into the synovial bursa of the gastrocnemius-semimembranosus muscle on the posterior side of the joint, causing an enlargement of the bursa cavity and forming a fossa cyst called a Baker cyst, where an elastic soft tissue mass can be palpated, and the patient complains of pain and swelling behind the knee, occasionally the cyst grows rapidly or ruptures and can cause symptoms similar to acute thrombophlebitis, called “pseudo-thrombophlebitis”. 7, hip Hip lesions are uncommon and often occur in the late stage of the disease, patients often complain of groin discomfort, followed by hip, lower back or knee pain, swelling and pressure pain are rare, and can only be judged by gait and joint movement restriction to have hip lesions. In the late stage, there may be destruction of the femoral head.