Capsular contracture is a condition where the immune system responds to foreign materials in the human body, mostly in the context of complications from breast implants and artificial joint prosthetics. It occurs when the collagen-fiber capsule shrinks, tightens, and compresses the breast implant, much like the collapse of a bubble gum bubble. Capsular contracture can be painful and discomforting, and might distort the aesthetics of the breast implant and the breast. The degree of an incidence of capsular contracture is graded using the four-grade Baker scale:

• Grade I — the breast is normally soft and appears natural in size and shape
• Grade II — the breast is a little firm, but appears normal
• Grade III — the breast is firm and appears abnormal
• Grade IV — the breast is hard, painful, and appears abnormal

Capsular contracture can happen around any type of breast implant (both saline and silicone) . The exact causes of this condition vary from patient to patient, but clinicians have a number of theories on what causes capsular contracture. Factors common to its incidence include bacterial contamination, rupture of the breast-implant shell, leakage of the silicone-gel filling, and hematoma. Smoking, radiation therapy, and autoimmune disorders are also thought to increase the risk of capsular contracture. Capsular contracture can be treated with surgical breast implant revision, which involves removing the implant and the capsule of scar tissue around it. In cases of mild capsular contracture, regular massaging of the breast can help to reduce the tension of the scar tissue.