TABLE I.

Definitions and Complications after Successful Anterior Cruciate Ligament Surgery

Condition	Definition
Anterior cruciate ligament injury	Injuries range from mild, such as a small tear, to severe, such as when the ligament tears completely or when the ligament and part of the bone separate from the rest of the bone.3,4,13,20
Arthrofibrosis (adhesive capsulitis)	Excessive scar tissue formation within the knee joint secondary to an inflammatory process, fibroblast hyperactivity, exaggerated endothelial proliferation, and disorganized deposition of the protein matrix that leads to stiffness, pain and loss of normal motion (loss of flexion, extension or both).29,67 Histologically, a dense collagen deposition is common.20 Arthrofibrosis can contribute to PTOA, and vice versa.
Post-traumatic osteoarthritis (PTOA)	A form of osteoarthritis from an accelerated form of inflammation, cartilage degeneration and joint dysfunction that causes stiffness and pain.3,4,31–34
Surgical trauma	Trauma from surgery itself could add to the molecular events and exacerbate acute joint injury, and later life complications. This area has received little attention.65