Extensor Tendon Lacerations

ABC7’s The More in the Morning team spoke with Dr. Michael K. Kim, Board-Certified Plastic Surgeon, to explain Extensor Tendon Lacerations, which can cause the finger to bend and not extend after an injury to the back of the hand or fingers.

Extensor tendons are just under the skin. They lie next to the bone on the back of the hands and fingers and straighten the wrist, fingers and thumb. They can be injured by a minor cut or jamming a finger, which may cause the thin tendons to rip from their attachment to bone. If not treated, an extensor tendon injury may make it hard to straighten one or more joints.

The diagnosis is evident by the appearance of the finger. Dr. Kim will often order x-rays to see if a piece of bone is pulled away and to make sure the joint is aligned.

Common Extensor Tendon Injuries

  • Mallet Finger

    Mallet Finger refers to a drooping end-joint of a finger. This deformity of the finger is caused when the tendon that straightens your finger (the extensor tendon) is damaged. When a ball or other object strikes the tip of the finger or thumb and forcibly bends it, the force tears the tendon that straightens the finger. The force of the blow may even pull away a piece of bone along with the tendon. The tip of the finger or thumb no longer straightens.

  • Boutonnière Deformity

    Boutonnière Deformity describes the bent-down (flexed) position of the middle joint of the finger. Boutonniere can happen from a cut or tear of the extensor tendon.


Tears caused by jamming injuries are usually treated with splints. Splints hold the tendon in place and should be worn at all times until the tendon is healed. The tendon may take six to twelve weeks to heal completely. Longer periods of splinting are sometimes needed.

Surgical repair may be considered when extensor tendon injuries include large bone fragments or joint mal-alignment. In these cases, pins, wires or even small screws are used to secure the bone fragment and realign the joint. Surgery may also be considered if splint wear is not feasible or if non-surgical treatment is not successful in restoring adequate finger extension. Surgical treatment of the damaged tendon can include tightening the stretched tendon tissue, using tendon grafts or even fusing the joint straight. Surgery to free scar tissue is sometimes helpful in cases of severe motion loss.

After treatment, hand therapy may be necessary to improve motion. It is important to find a specialist shortly after the injury in order for the best recovery in the shortest amount of time.

Lipomas, however, are lumps of fatty tissue mostly appearing on the forehead, neck, shoulders, back, chest, abdomen, arms, buttocks and thighs. Although not sure of causation, experts believe genetics, injury or trauma, weight issues or obesity, liver disease, alcohol abuse or glucose intolerance are factors that can cause lipomas. Most lipomas are also found to be benign.

Tumors, another category of lumps and bumps found on the skin and elsewhere on the body, are accumulations of cells that can be either benign or malignant. Malignant tumors are cancerous cells that can cluster anywhere, grow rapidly, and can also spread or metastasize. Malignant skin cancer tumors are only one example and require a more aggressive diagnosis and treatment than just surgical removal. However, most common benign tumors, in addition to Lipomas as mentioned above, include: Fibroids (uterine benign tumors), Adenomas (colon polyps) and Hemangiomas (liver benign tumors).

Dr. Kim is one of the few board-certified hand surgeons in the area. In addition to doing 5 years of general surgery, 2 years of plastic surgery training, 1 year of research in wound healing, he also completed a 1 year hand surgical fellowship at the famous Kutz-Kleinert hand institute in Louisville, KY. Dr. Kim participated in the first US hand transplant in 1999. Dr. Kim has passed the intensive examinations to obtain (CAQH) board certification in hand surgery. He is also a member of the ASSH (American Society of Surgery of the Hand). He performs many of his hand surgeries with WALANT ( wide awake local anesthesia no tourniquet ) which makes the procedure and recovery fast and comfortable

Learn More About Dr. Michael K. Kim

Contact Us

Phone: 239-939-5233
Email Dr. Kim


RealSelf Reviews

5.0 stars from 9 reviews