In a proximal tibial valgus-producing osteotomy (high tibial osteotomy) for medial compartment knee osteoarthritis, the surgical goal is to shift the mechanical axis of the lower limb to what percentage across the tibial plateau?
- A 62% (slightly lateral to center — Fujisawa point) ✓
- B 50% (neutral, through the center of the knee)
- C 30% (medial to center to offload lateral compartment)
- D 75% (far lateral for maximum offloading)
Explanation
The Fujisawa point (62% across the tibial plateau from the medial edge) is the target for mechanical axis correction in medial-compartment osteoarthritis HTO. This slightly overcorrects to the lateral compartment (62% = lateral of center) to offload the diseased medial compartment, reduce pain, and slow cartilage degradation. Neutral (50%) is insufficient offloading; >65% risks excessive lateral compartment loading. This target translates to approximately 3-5° of valgus overcorrection on standing X-ray. HTO is most appropriate for young, active patients with isolated medial OA and preserved lateral compartment.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
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Written and medically reviewed by the StethoPrep medical team.