Osteoarthritis

Osteoarthritis normally affects older people. It is a disease where joints wear out. As the joint surface wears away, it sheds particles which stimulate the joint lining to produce fluid. This causes the joint to swell. When the joint cartilage wears away, the core of the bone becomes exposed. The exposed bone rubs against other exposed bone.

Synovial fluid analysis

Synovial fluid examination^[1][2]

Type	WBC (per mm3)	% neutrophils	Viscosity	Appearance
Normal	<200	0	High	Transparent
Osteoarthritis	<5000	<25	High	Clear yellow
Trauma	<10,000	<50	Variable	Bloody
Inflammatory	2,000–50,000	50–80	Low	Cloudy yellow
Septic arthritis	>50,000	>75	Low	Cloudy yellow
Gonorrhea	~10,000	60	Low	Cloudy yellow
Tuberculosis	~20,000	70	Low	Cloudy yellow
Inflammatory: Arthritis, gout, rheumatoid arthritis, rheumatic fever

Management

Exercise

Weight loss and exercise give long-term treatment.^[3] Short-term treatments usually have risk of harm (in the long-term).^[4] The way to get through the pain is to be active (exercise), not rest. This is similar to the management of back pain, but other conditions require rest.

Symptoms

Joints will be stiff and painful, and may be swollen. The pain may be worse after exercise. It may get harder to move the joint.

An X-ray image of a knee with osteoarthritis.