Understanding why anatomical bone correction is essential for effective knee osteotomy
Successful knee osteotomy relies on addressing the true anatomical deformity rather than merely shifting the mechanical axis. When surgeons focus only on global alignment targets, they may unintentionally leave underlying bone abnormalities uncorrected, increasing the risk of joint line obliquity and compromised biomechanics.
This study explores how often modern osteotomy planning truly aims at anatomical bone correction.
How the researchers evaluated planning accuracy using simulated osteotomy corrections
The authors retrospectively analysed 327 patients who underwent tibial or femoral osteotomy. Each case was recreated using 3D planning software to determine whether the intended correction properly addressed the anatomical deformity. The simulation identified residual abnormalities and categorised them as:
- Type 1: Under- or over-correction at the correct anatomical site.
- Type 2: Correction performed at the wrong anatomical level (e.g., tibia instead of femur).
The study also examined the relationship between pre-operative varus/valgus alignment and the likelihood of non-anatomic correction.
What the study revealed about residual deformity and alignment accuracy
- 50.7% of planned tibial osteotomies still showed anatomical abnormalities after simulation.
- Femoral corrections were substantially more accurate, with only 6.7% showing residual deformity.
- Patients with more severe varus deformity had a significantly higher risk of receiving a non-anatomical correction plan.
- Many plans corrected mechanical axis deviation but failed to correct the bone segment where the deformity originated, risking long-term loading imbalance and joint line tilt.
Why surgeons should move beyond mechanical axis targets and incorporate anatomical planning
The study emphasises that mechanical axis targets alone are insufficient for optimal osteotomy outcomes. Anatomical localisation of deformity—whether femoral, tibial, or combined—must guide decision-making. Planning that neglects bone-specific angles (MPTA, LDFA, CORA markers, joint line orientation) may leave residual deformity or create unwanted joint line obliquity, potentially impacting both function and longevity of the correction.
Key insights for improving osteotomy planning and execution
- Less than half of osteotomies around the knee are planned with true anatomical correction in mind.
- Tibial osteotomies are especially prone to leaving residual deformity when anatomical mapping is not prioritised.
- Pre-operative varus alignment strongly predicts non-anatomical planning errors.
- Comprehensive deformity analysis—including joint line orientation and bone-segment angles—should be mandatory in modern osteotomy planning.
