What does extensor tendon subluxation feel like?

Most patients describe a snapping or popping over the knuckle when straightening the finger, often paired with weakness when making a fist and trouble extending the finger from a flexed position. There may be a visible bump or shift on the back of the hand. Some patients have no symptoms at all and the diagnosis is incidental.

Can it be treated without surgery?

Acute injuries treated within 2 to 3 weeks often heal with an extension splint worn for 4 to 6 weeks, followed by guided hand therapy. Older injuries or those that have failed splinting usually need surgery, because the torn sagittal band will not scar back into place without help.

What does surgery involve?

Surgery is a same-day, outpatient procedure done through a small incision over the affected knuckle. The torn sagittal band is repaired directly when the tissue is good. When it is not, a strip of nearby tendon is used to reconstruct the restraint. The goal is to re-center the tendon over the knuckle so it tracks normally during finger motion.

How long is recovery after surgery?

Most patients are in a protective splint for 4 to 6 weeks post-op, with hand therapy throughout, and resume light desk work during that window. Strengthening and gradual return to gripping, lifting, and recreation typically happen between 6 and 12 weeks. Return to contact sports or high-demand hand use is usually at 3 months.

Extensor Tendon Subluxation, Steven J. Lee, MD

Extensor Tendon Subluxation: when the tendon slips off the knuckle.

The extensor tendons on the back of the hand should stay centered over each knuckle. When the small bands that hold them in place tear, the tendon slips into the valley between knuckles, and the finger feels weak or catches when you straighten it. Acute injuries often heal with splinting; chronic cases need surgical realignment.

The extensor tendons are the structures that straighten your fingers. Each one runs over the back of a knuckle, held centered by a small soft-tissue sleeve called the sagittal band. When the sagittal band tears, the tendon slips off the knuckle and slides into the valley between the metacarpal heads.

The usual cause is a punch, a fall onto a closed fist, or chronic inflammation of the joint, often from rheumatoid arthritis or other autoimmune condition. Patients describe a snapping or catching as they straighten the finger, weakness when making a fist, or an inability to extend the finger fully.

Anatomy

The extensor tendons run from forearm muscles, across the back of the wrist and hand, to attach to the fingers. They function like ropes that straighten the fingers. Over each metacarpophalangeal (MCP) joint, the tendon is held centered by the sagittal bands, thin but strong tissues on either side.

When a sagittal band tears, the tendon loses its restraint and slips into the gap between knuckles, most often toward the ulnar (pinky) side.

Causes

Trauma is the most common cause: punching a hard object or falling onto a closed fist, sometimes called a 'boxer's knuckle'.

Inflammatory conditions, especially rheumatoid arthritis, weaken the sagittal bands over time and can lead to spontaneous subluxation without a discrete injury.

Symptoms

A snapping or popping sensation as the tendon shifts off and back onto the knuckle.

Pain over the back of the knuckle, especially when making a fist.

Difficulty straightening the affected finger from a flexed position, while passive straightening is preserved.

Some patients have a visible bump or asymmetry over the knuckle. In milder cases there are no symptoms at all and the diagnosis is incidental.

Diagnosis

The diagnosis is usually clinical. Dr. Lee can see and feel the tendon shift as the patient flexes and extends the finger.

X-rays may be obtained to rule out fractures or arthritis. MRI or ultrasound is occasionally used when the picture is unclear, and rheumatologic workup is recommended when an inflammatory cause is suspected.

Non-surgical treatment

Acute injuries, treated within the first 2 to 3 weeks, often heal with a relative motion splint. The finger is held in full extension for 4 to 6 weeks to allow the sagittal band to scar back into place, then progressively weaned with the guidance of a hand therapist.

When the injury is older or the splint trial has failed, conservative care alone is unlikely to restore stability.

Surgical treatment

Chronic subluxation and acute injuries that fail splinting are treated surgically. The procedure is performed as outpatient surgery through a small incision over the affected knuckle.

The sagittal band is repaired directly when the tissue is good, or reconstructed using a slip of adjacent tendon when the native tissue is too damaged to hold. The goal is to re-center the tendon over the knuckle so it tracks normally with finger motion.

Dr. Lee's approach

Dr. Lee tailors the approach to the cause: traumatic tears in younger patients are usually amenable to direct sagittal band repair, while inflammatory or chronic cases more often need a reconstruction. In either case the priority is centering the tendon and protecting the repair during early healing.

Hand therapy is started early under careful supervision so the joint does not stiffen while the soft tissue heals.

Recovery timeline

Acute (splinting), weeks 1 to 6
Continuous extension splint for 4 to 6 weeks, removed only for skin care, with gradual weaning under hand-therapy supervision.
Post-op, weeks 1 to 2
Hand elevated above the heart; clean, dry dressing; sutures removed at 7 to 10 days.
Weeks 2 to 6
Custom hand-therapy splint and protected motion. Most desk work resumes during this window.
Weeks 6 to 12
Strengthening and gradual return to gripping, lifting, and recreational use.
3 months and beyond
Return to contact sports, full strength, and any high-demand hand use.

This page is general educational content authored by Dr. Lee. It is not a substitute for individual medical advice. Every patient's case is different, book a consultation to discuss yours.

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