What does a mild positive ulnar variance indicate?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: May 5, 2026 • View editorial policy

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question

Mild Positive Ulnar Variance: Clinical Significance

Mild positive ulnar variance indicates that the ulna extends slightly longer than the radius at the wrist joint, which can predispose to ulnar-sided wrist pathology including triangular fibrocartilage complex (TFCC) tears, ulnar impaction syndrome, and degenerative changes in the ulnar compartment of the wrist.

What It Means Anatomically

Ulnar variance refers to the relative length relationship between the distal ulna and radius at the wrist. When measured on posteroanterior radiographs with the wrist in neutral position, positive ulnar variance means the ulnar articular surface sits distal (longer) relative to the radial articular surface 1.

Key measurement considerations:

  • Radiographs must be obtained in neutral position and rotation for accurate measurement 1
  • Standard measurement is performed on posteroanterior views 2
  • The measurement can be affected by forearm rotation and X-ray beam angle 3

Clinical Implications and Associated Pathology

Positive ulnar variance is harmful to the ulnar compartment of the wrist because it increases mechanical loading between the ulnar head and carpal bones 4. This creates a cascade of degenerative changes:

Primary Associated Conditions:

  1. TFCC Pathology

    • Degeneration and perforation of the triangular fibrocartilage complex 4
    • TFCC foveal tears can themselves cause approximately 0.56 mm of radiographic positive ulnar variance 5
    • This creates a diagnostic challenge: is the positive variance causing TFCC damage, or is TFCC damage causing apparent positive variance?

  2. Ulnar Impaction Syndrome

    • Cartilaginous wear of carpal bones (particularly lunate) 4
    • Chronic ulnar-sided wrist pain exacerbated by loading 6
    • Progressive degenerative changes in the ulnocarpal joint

  3. Focal Lunate Necrosis

    • Associated with chronic increased loading in the ulnar compartment 2

Important Clinical Caveats

Critical diagnostic pitfall: A TFCC foveal tear can create 0.56 mm of apparent positive ulnar variance on radiographs 5. This means what appears to be ulnar impaction syndrome may actually be secondary to ligamentous injury rather than true anatomic positive variance. After arthroscopic TFCC foveal repair, this radiographic positive variance resolves 5.

Measurement reliability issues:

  • Standard radiographic measurements can be unreliable due to beam angle and forearm position 3
  • 3D CT measurements show that ulnar variance changes with forearm rotation vary among individuals 3
  • Some patients with ulnar impaction have pain with supination rather than pronation, contrary to traditional teaching 3

Biomechanical Factors

Positive ulnar variance can develop from:

  • Genetic factors and age 4
  • Repetitive loading (seen in gymnasts and athletes) 2, 4
  • Central band interosseous ligament deficiency - creates a "parallelogram effect" where the radius shifts proximally, producing positive ulnar variance 6

Clinical Workup Algorithm

When mild positive ulnar variance is identified on radiographs:

  1. Correlate with clinical presentation:

    • Ulnar-sided wrist pain location and character
    • Provocative positions (grip, pronation, supination)
    • Duration and progression of symptoms

  2. Advanced imaging if symptomatic 1:

    • MRI without contrast is usually appropriate for evaluating TFCC lesions and ulnar-sided pain
    • High-resolution sequences (3.0T preferred over 1.5T) for TFCC evaluation 1
    • MR arthrography may be appropriate if direct joint injection is feasible and higher sensitivity needed 1
    • CT arthrography is an alternative with similar accuracy to MR arthrography 1

  3. Consider underlying ligamentous injury:

    • If TFCC foveal tear is identified, the positive variance may resolve with ligament repair 5
    • Avoid misdiagnosing as primary ulnar impaction syndrome requiring shortening osteotomy

Treatment Implications

If considering ulnar shortening osteotomy for symptomatic positive ulnar variance with TFCC pathology, account for the 0.56 mm of variance induced by the TFCC tear itself to prevent over-shortening 5. The ligamentous component should be addressed first, as repair may normalize the radiographic variance.

Athletes demonstrate more positive ulnar variance than non-athletes and variance increases over time with repetitive loading 2, making this particularly relevant in athletic populations with ulnar-sided wrist pain.

References

1
Guideline

acr appropriateness criteria<sup>®</sup> chronic wrist pain.

Journal of the American College of Radiology, 2018

4
Research

Ulnar variance: facts and fiction review article.

Acta orthopaedica Belgica, 1994

Related Questions

Does ulnar positive variance require treatment?
1. What is the major health problem resulting from a pulse deficit? (A) Bradycardia (B) Activity intolerance (C) Decreased cardiac output (D) Impaired tissue perfusion. 2. What should the nurse do when a pulse deficit is suspected? (A) Measure the radial pulse for one minute, then measure the apical pulse for one minute (B) Measure the radial pulse for 30 seconds, then measure the apical pulse for 30 seconds (C) Measure the radial pulse for one minute, wait five minutes, then measure the apical pulse for one minute (D) Ask another health‑care provider to count the radial pulse while the nurse counts the apical pulse. 3. After identifying a pulse deficit, which action should the nurse perform? (A) Reassess the apical‑radial pulse in five minutes (B) Assess the patient for signs of decreased cardiac output (C) Notify the primary health‑care provider of the pulse deficit (D) Initiate interventions directed toward managing the patient’s symptoms. 4. A patient has oral temperature 36.8 °C, radial pulse 112 weak and thready, apical pulse 117 regular, respirations 24 regular, blood pressure 104/56 right arm, 102/50 left arm; what is the pulse deficit? (A) 2 (B) 5 (C) 6 (D) 48. 5. Which of the following is an early manifestation of decreased cardiac output? (A) Fatigue (B) Substernal pain (C) Nail‑bed cyanosis (D) Shortness of breath.
In a 24-year-old woman who experiences severe nausea, shakiness, and dizziness lasting about 30 minutes after sexual intercourse, what are the possible differential diagnoses?
How should a 2-year-old child presenting with a dry cough and wheezing be managed?
What is the appropriate management for a 10‑month‑old infant with cough, wheezing, coarse breath sounds, and diarrhea?
Is doxycycline 100 mg daily recommended as an adjunct to HIV pre‑exposure prophylaxis (PrEP) for preventing bacterial STIs, and what are the contraindications and monitoring requirements?
What are the differential diagnoses for a diffuse, generalized rash in an adult?
In a healthy asymptomatic female with sinus rhythm and an isolated incomplete right bundle branch block, is this finding concerning or a normal variant?
Can spironolactone improve psoriasis?
For sciatica with neuropathic pain, is gabapentin preferable to cyclobenzaprine (Flexeril) as treatment?
What is the appropriate oral prednisolone dose for a 10‑month‑old child?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.