Why does my pinky-side wrist hurt only with certain motions?

If the ulna is even 2 to 3 millimeters longer than the radius, it will impact the small bones and TFCC on the pinky side of the wrist during forearm rotation and wrist extension, like twisting a doorknob or doing a push-up. Activities that don't load the joint in those positions often feel fine. An X-ray measurement of ulnar variance is what confirms the diagnosis.

Do I need surgery, or can it be managed without?

Many patients do well with splinting for 4 or more weeks, activity modification, and either a corticosteroid injection or PRP. Surgery is considered when symptoms persist despite a real trial of conservative care, when imaging shows progressive cartilage damage, or when the variance is large enough that non-operative treatment is unlikely to succeed.

What is the wafer procedure?

The wafer procedure is a minimally invasive arthroscopic surgery that shortens the ulna by removing a thin slice (wafer) of bone from its tip through a wrist scope. It is best for variance under 3 to 4 millimeters with preserved cartilage. Recovery is faster than a formal osteotomy because no plate or fracture-healing is involved.

When is a formal ulnar shortening osteotomy needed instead?

When the variance is larger than about 3 to 4 millimeters, or when associated cartilage damage is more extensive, a formal shortening osteotomy with a plate and screws is more reliable. Bone-healing extends the recovery (typically 3 to 6 months to full strength) but the result is durable.

Ulnar Impaction Syndrome, Steven J. Lee, MD

Ulnar impaction syndrome (sometimes called ulnocarpal abutment) is a common cause of pain on the pinky side of the wrist. It occurs when the ulna, one of the two forearm bones, is too long relative to the radius. With every forearm rotation the ulna impacts the small carpal bones and the TFCC (triangular fibrocartilage complex), causing pain, swelling, and sometimes cartilage damage.

Some patients are born with a naturally long ulna ('ulnar positive variance'). In others the imbalance develops after a distal radius fracture that heals slightly shortened, making the ulna effectively longer. Inflammatory conditions can also play a role.

Anatomy

The wrist sits at the intersection of three structures: the distal radius, the distal ulna, and the carpal bones. The TFCC is a small cartilage and ligament complex that cushions the load between the ulna and the carpal bones during forearm rotation and gripping.

When the ulna is even 2 or 3 millimeters too long, the TFCC and adjacent cartilage take a load they were never designed for, and degenerative tears develop over time.

Causes

Congenital ulnar positive variance: a naturally longer ulna present from birth.

Prior distal radius fracture that healed short, leaving the ulna relatively longer.

Inflammatory arthritis affecting wrist alignment.

Symptoms

Pain on the pinky side of the wrist, worse with twisting motions (turning a doorknob, pouring a pot), wrist extension (push-ups), and gripping.

Onset can be sudden after a specific activity or gradual from cumulative overuse.

Some patients describe clicking, swelling, or a feeling of weakness with rotation.

Diagnosis

Examination focuses on point tenderness over the ulnar wrist and provocative maneuvers that load the TFCC. Dr. Lee compares wrist motion and stability to the opposite side.

X-rays measure ulnar variance directly: a difference of a few millimeters is enough to be symptomatic. MRI may be ordered to assess the TFCC and adjacent cartilage when surgery is being considered.

Non-surgical treatment

Initial care emphasizes wrist rest, splinting in a removable wrist brace for 4 or more weeks, and avoiding the activities that load the joint (push-ups, gripping-heavy training, twisting).

Corticosteroid injections can provide meaningful temporary pain relief and help confirm the diagnosis. PRP (platelet-rich plasma) is sometimes used in early or biologically promising cases. Dr. Lee was among the first surgeons in NYC to use PRP for upper-extremity injuries and performs more than 250 PRP procedures per year.

Surgical treatment

When the variance is small (under 3 to 4 millimeters) and the cartilage is preserved, the ulna can often be shortened arthroscopically. The 'wafer procedure' removes a thin slice of bone from the end of the ulna through a wrist scope. Patients typically wear a removable splint for 4 to 6 weeks afterward.

When the variance is larger or the cartilage is more involved, a formal ulnar shortening osteotomy with a plate and screws is the more reliable option. In selected inflammatory cases the head of the ulna is removed (Darrach or related procedures).

Dr. Lee's approach

Dr. Lee is fellowship trained in both Hand and Upper Extremity Surgery and Sports Medicine, and regularly instructs other surgeons in cadaver labs on the wafer procedure and ulnar shortening osteotomies. Procedure selection is matched to the variance, the cartilage status, and the patient's activity demands.

For active patients with smaller variance, the arthroscopic wafer is favored when feasible because of the faster recovery. For larger variance or complex cases, a formal shortening with internal fixation is the more predictable solution.

Recovery timeline

Weeks 1 to 4 (wafer)
Removable splint, gentle motion, and edema control.
Weeks 4 to 12 (wafer)
Progressive hand therapy and return to most daily activities.
3 to 4 months (wafer)
Return to full strength and most sport.
Weeks 1 to 4 (formal shortening)
Long-arm cast or splint to protect the osteotomy.
Weeks 4 to 12 (formal shortening)
Removable splint and hand therapy beginning around week 6 once bone-healing is confirmed.
3 to 6 months (formal shortening)
Return to gripping, twisting, and contact sport.

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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Ulnar Impaction Syndrome: pinky-side wrist pain, explained.