If the pain is judged as coming from the joint in question then certain decisions have to be made as to the causes of this. Inflammatory arthritis is the first category to be considered, with inflammatory changes affecting the the synovial membranes and the entheses, the junctions between the bones and the ligaments and tendons. Non-inflammatory arthritis involves changes in the structure and function of the joint, occurring as damage to the menisci or the articular cartilage lining the joint or secondary to changes in the joint which can be from a variety of causes.
There can be significant knee pain without any discernible pathology perhaps due to clinical changes not yet presenting in early disease or in pain conditions such as fibromyalgia. Two or more types of disorder can occur within one joint at the same time and an inflammatory arthritis can lead to the joint becoming less stable and more damaged. One of the main symptoms of such joint disorders is pain and with inflammatory causes pain is present with the joint moving or at rest and usually worse at the start of the movement. With non-inflammatory arthritic changes the pain is usually better when resting and worse with movement.
If the arthritic changes become very advanced in the spine or major joints patients may suffer pain even when they are resting and also at night. Larger joint pain is less clearly localised to the joint than pain from smaller joints, with hip pain possibly referred to the buttock, lateral thigh, groin or front of thigh. Stiffness is common with arthritis and a difficult symptom to define, but it means difficulty moving a joint, especially after a period of resting, which goes off with movement. Inflammatory joint stiffness may last longer, for example half an hour to an hour, while osteoarthritic stiffness may ease after 10-15 minutes.
There are several changes which can occur in a joint to make it swell. If the joint is affected by non-inflammatory arthritis then bony growths form at the margins of the joints and the end of the fingers or the knees become knobbly joints. Or an effusion, a collection of fluid within a joint capsule, can form secondary to inflammatory disease and can be drawn off by injecting the joint. It is common for an affected joint to show a degree of loss of movement either because the soft tissues have tightened up, the joint is damaged anatomically or by restriction from pain and inflammation.
An arthritic joint or joints can significantly interfere with activities of daily living (ADL) such as climbing stairs, maintaining self care and dressing. Part of these difficulties may be related to atrophy and weakness of muscles, which in combination with pain point to a musculoskeletal cause rather than muscle or nerve pathology. Muscle weakness interferes with normal actions such as gripping objects, standing up from sitting or walking any distance without falling. Fatigue and malaise can be present in systemic arthritis as it affects the whole body. The onset of arthritic symptoms can be rapid or slow and steady, with infections, trauma and crystal causes tending to come on rapidly.
The develop of joint symptoms over weeks to months is more common and is the case in osteoarthritis and rheumatoid arthritis, the two most common conditions. If symptoms are present less than six weeks they are acute, from 6 to 12 weeks they are sub-acute and over 12 weeks they are termed chronic, although this is not a rigid classification. Joint involvement varies with different patterns, such as episodes of joint pain with pain-free times in between as in gout, to the persistence of joint problems as further joints are involved. Arthritis is also classified by the number of joints affected with polyarthritis affecting five or more, oligoarthritis two to four and monoarthritis one joint only.
Non-symmetrical and symmetrical joint patterns of involvement can occur. SLE and rheumatoid arthritis tend to affect the same joints on each side of the body in a symmetrical pattern while psoriatic arthritis and reactive arthritis involve different joints on each side of the body, the asymmetrical pattern. Joints may be involved in different patterns also, for example distal finger joints in osteoarthritis and psoriatic arthritis but not in rheumatoid arthritis.
Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about
Physiotherapists, physiotherapy,
Physiotherapists in Exeter, back pain, orthopaedic conditions, neck pain and injury management. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.
