On a long-leg standing radiograph of a healthy adult, the medial proximal tibial angle (MPTA) measures closest to:
- A 101 degrees
- B 93 degrees
- C 87 degrees ✓
- D 79 degrees
Correct answer: C. 87 degrees
Explanation
The MPTA, the angle between the tibial mechanical axis line and the proximal tibial joint orientation line, has a normal mean of 87 degrees (range roughly 85 to 90 degrees). D value below this range indicates proximal tibial varus, while a value above it indicates valgus of the proximal tibia. The corresponding lateral distal femoral angle averages about 88 degrees. Recognising these normal joint orientation angles is the first step of the malalignment test.
Reference: Campbell's Operative Orthopaedics, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.