Skip to main content
OrthoVellum
Knowledge Hub

Study

  • Topics
  • MCQs
  • ISAWE
  • Operative Surgery
  • Flashcards

Company

  • About Us
  • Editorial Policy
  • Contact
  • FAQ
  • Blog

Legal

  • Terms of Service
  • Privacy Policy
  • Cookie Policy
  • Medical Disclaimer
  • Copyright & DMCA
  • Refund Policy

Support

  • Help Center
  • Accessibility
  • Report an Issue
OrthoVellum

© 2026 OrthoVellum. For educational purposes only.

Not affiliated with the Royal Australasian College of Surgeons.

Trauma
advanced
X-Type

Deformity Analysis - CORA, Mechanical Axis Deviation, and Osteotomy Planning

Deformity Correction

A 35-year-old man presents 18 months after a tibial shaft fracture with a painful varus deformity of the left leg. Clinical examination shows obvious varus alignment. Long-leg standing radiographs are obtained. The mechanical axis line passes through the medial tibial plateau, 25mm medial to the knee center. Analysis shows the proximal tibial joint orientation is normal (MPTA 87 degrees) but the distal tibial joint orientation is abnormal (LDTA 78 degrees, normal 89-90 degrees). The CORA is identified at the level of the malunited fracture. Regarding deformity analysis principles and CORA:

Mark each as TRUE or FALSE

A

MECHANICAL AXIS of lower limb: line from HIP CENTER (center of femoral head) to ANKLE CENTER (midpoi...

B

ANATOMICAL AXIS vs MECHANICAL AXIS: femoral anatomical axis is LINE through shaft (5-7° valgus to me...

C

The mechanical axis normally passes through the lateral tibial plateau; MAD of 50mm medial is normal...

D

CORA (Center of Rotation of Angulation): the INTERSECTION point of the proximal and distal mechanica...

E

MALALIGNMENT TEST: draw proximal and distal joint orientation lines; if they are PARALLEL, deformity...

Answer the questions to see explanations

Click T (True) or F (False) for each option