Why this investigation is important: planning deficits in knee osteotomies
Correct osteotomy around the knee (for varus or valgus malalignment) requires detailed pre-operative planning, specifically anatomical bony correction rather than simply utilising a generic mechanical axis target.
This study is important because it evaluates how often knee osteotomies are actually planned with anatomical correction in mind—and finds a concerning deficit.
Study design: cohort, methods and measurements
This was a retrospective cohort study analysing osteotomies around the knee (both femoral and tibial) in a surgical database. The key evaluation was whether pre-operative and intra-operative planning targeted anatomic bone angles (rather than only global mechanical axis) and whether post-operative correction achieved those anatomical criteria. The authors used full-length alignment radiographs and calculated whether the planned correction met “anatomical” thresholds. The study found that in less than 50% of cases the planning was aligned with an anatomical correction intent.
They noted that non-anatomic correction (i.e., not restoring bone segment angles) occurred in more than half the cases—and particularly when pre-operative alignment was in varus.
Key findings: frequency of anatomical planning and implications
- Less than half of knee osteotomies were planned according to anatomical bone correction (instead of solely mechanical axis correction).
- Correction that was non-anatomic (i.e., residual anatomical deformity) was found in more than 50% of cases analysed.
- Non-anatomic corrections were more common in patients with pre-operative global varus alignment.
- The authors conclude that if anatomical values (bone angles) are not considered, there is a risk of creating an undesirable oblique joint line (joint line obliquity, JLO) which can adversely affect knee biomechanics.
Clinical implications: what surgeons should consider
- Surgeons performing osteotomies around the knee should extend planning beyond just mechanical axis (hip-knee-ankle) to include anatomical bone angles (e.g., proximal tibial angle, distal femoral angle).
- When planning correction, assessing whether the deformity is in bone (femur/tibia) or joint (intra-articular) is key. Ignoring anatomic correction increases the risk of residual deformity and joint line obliquity, which may lead to suboptimal functional outcomes.
- Particularly in varus-aligned patients, more attention is needed: the study found higher incidence of non-anatomic correction in varus cases.
- The implication for rehabilitation and long-term joint health is that non-anatomic correction may predispose to cartilage overload, altered biomechanics, and potentially earlier failure or arthroplasty.
Take-away messages for practice and performance
- In contemporary knee osteotomy practice, anatomical bone correction is planned in fewer than half of cases.
- More than half of procedures result in non-anatomical correction, risking joint line obliquity.
- Varus malalignment patients are at higher risk of non-anatomic correction if anatomical planning is not applied.
- Incorporating anatomical bone angle targets into osteotomy planning may improve alignment quality and long-term joint biomechanics.
Sources used in report overview:
- https://www.sciencedirect.com/science/article/pii/S1877051721001222 (ScienceDirect)
- https://www.em-consulte.com/article/1446735/les-osteotomies-autour-du-genou-sont-planifiees-da (EM Consulte)
- https://www.researchgate.net/publication/351761973_Les_osteotomies_autour_du_genou_sont_planifiees_dans_moins_de_la_moitie_des_cas_selon_une_correction_osseuse_anatomique (ResearchGate)
