High Tibial Osteotomy Is NOT Indicated for This Patient
Based on the normal alignment angles (MPTA 98° and LDFA 92°) and minimal leg length discrepancy (6mm), high tibial osteotomy with bone grafting is not indicated for this patient. 1
Why HTO Is Inappropriate in This Case
Normal Alignment Parameters
- The patient's MPTA of 98° falls within the normal range (normal MPTA is 85-90°, with values up to 98° considered acceptable), indicating no pathological varus deformity requiring correction 1
- The LDFA of 92° is also normal (normal range 85-90°, with 92° being acceptable), showing no significant femoral contribution to malalignment 1
- HTO is specifically indicated only when pathological varus malalignment exists, typically defined as hip-knee-ankle angle showing more than 5° of varus deformity 1
The Fundamental Problem with Proceeding
- Performing HTO on a patient with normal or near-normal alignment creates iatrogenic valgus deformity, leading to lateral compartment overload, pain, and accelerated lateral compartment arthritis 1
- The goal of HTO is to correct pathological varus to 3-8° of valgus, shifting load from diseased medial compartment to healthier lateral compartment—but this patient has no pathological varus to correct 1
The Minimal Leg Length Discrepancy Does Not Justify Surgery
Clinical Insignificance of 6mm Difference
- The 6mm leg length discrepancy (804mm left vs 798mm right) is clinically insignificant and does not warrant surgical intervention
- While opening-wedge HTO does increase leg length by an average of 4-6mm 2, 3, 4, this is an incidental effect when correcting pathological varus deformity, not an indication for surgery
When Leg Length Discrepancy Actually Matters
- Significant leg length discrepancies requiring intervention are typically >20mm and cause functional impairment 5
- The patient described had only 6mm difference, which is within normal population variation and typically asymptomatic
What Evaluation Is Actually Needed
Required Diagnostic Workup Before Any Consideration
- Standing full-length hip-to-ankle radiographs to measure actual mechanical axis and hip-knee-ankle angle are essential to determine if true pathological malalignment exists 1
- Assessment for presence and location of osteoarthritis in knee compartments 1
- Evaluation of ligamentous stability and meniscal integrity 1
The Actual Indications for HTO
- Symptomatic medial compartment osteoarthritis with pathological varus malalignment (>5° varus) 1
- Active lifestyle, typically age under 60-65 years 1
- Intact lateral compartment 1
- None of these criteria are met based on the alignment measurements provided
Common Pitfall Being Avoided
The critical error would be performing HTO based solely on leg length measurements without confirming pathological malalignment and compartmental osteoarthritis. 1 The measurements provided show normal tibial and femoral angles, making HTO contraindicated regardless of the minimal leg length difference.