High Tibial Osteotomy (HTO)

Core Concept

• HTO realigns the mechanical axis to unload the medial compartment

• Primary goal: shift the weight-bearing axis to neutral or slight valgus — Fujisawa point: 62–66% of tibial plateau width

• Bridge treatment: buys 10–15 years before TKA in well-selected patients

Indications

• Symptomatic medial compartment OA with varus malalignment (HKA <177°)

• Age <65, high activity demand

• Failed conservative management >3 months

• Kellgren-Lawrence grade 2–3 (grade ≥3 acceptable in carefully selected cases — see survival data below)

• Intact or reconstructable lateral and patellofemoral compartments

Bonus indications:

• ACL-deficient knee + varus + medial OA → HTO reduces anterior tibial translation

• Medial meniscus root tear + varus → combined HTO + root repair improves objective outcomes

• Osteochondral lesion + varus malalignment → unloading prior to cartilage restoration

Contraindications

• Lateral or patellofemoral compartment involvement

• Inflammatory arthropathy

• Fixed flexion contracture >15°

• Severe osteoporosis

• BMI >35 (relative)

• Active smoker (relative — delayed union risk)

MOW vs LCW — Quick Comparison

Bottom line: Comparable clinical scores for pain, Lysholm, and HSS. At 10 years, MOW shows significantly better survivorship. Choose based on slope management and associated pathology.

Survival Data

Annual failure rates markedly increase after 10 years — counsel patients accordingly.

Risk Factors for Failure

OA Grade: KL >2 is a significant independent predictor of failure. Grade ≥3 requires careful patient selection.

Age paradox: Younger patients fail sooner.

• Age 40–49 → TKA conversion rate 14.2%

• Age 50–59 → 6.7%

• Age 60–69 → 2.3%

Joint Line Obliquity (JLO): Target neutral JLO (177°–183°) postoperatively. Deviation → worse WOMAC, stiffness, and function. MPTA should remain ≤95°.

Concomitant cartilage repair (microfracture, ACI): Does not significantly improve overall survivorship vs isolated HTO. Select wisely.

Surgical Pearls

Don't overcorrect. Target 2–3° valgus of mechanical axis. Overcorrection → lateral compartment overload and technically demanding TKA later.

Hinge fracture = most feared intraoperative complication. Preserve a 10–15 mm lateral hinge.

Slope matters. MOW increases posterior tibial slope — advantage in ACL-deficient knees, disadvantage after ACL reconstruction.

Conversion to TKA — What to Expect

• Prior HTO makes TKA technically more challenging: altered anatomy, soft tissue scarring, bone loss, residual deformity

• TKA revision rate after HTO: OR 2.09 vs primary TKA

• Most common failure modes: aseptic loosening, deep infection

• Stemmed tibial implants often required for stability

• Neutral JLO at index HTO → significantly better TKA outcomes later

Ideal Patient Profile

Age <65 · Varus malalignment · KL 2–3 · Intact lateral compartment · High activity demand · BMI <35

Pitfalls

1. Inadequate Deformity Analysis

• Focusing only on the tibia and missing a femoral component

• Performing a single osteotomy in multiapical deformities → residual malalignment

• Lack of full-length standing alignment radiographs → most common planning error

2. Overcorrection / Undercorrection

• Overcorrection (>3–5° valgus)
  → lateral compartment overload
  → accelerated lateral OA
  → technically more difficult future TKA

• Undercorrection
  → persistent symptoms
  → early failure

Most common cause of failure: incorrect target alignment

3. Ignoring Posterior Tibial Slope

• MOW → increases slope

• LCW → decreases slope

Common mistakes:

• Performing MOW after ACL reconstruction → increased graft stress

• Failing to adjust slope in ACL-deficient knees → persistent instability

4. Lateral Hinge Fracture

• Most critical intraoperative complication

• Risk factors:

  • Thin hinge (<10 mm)

  • Excessive opening

  • Incorrect osteotomy orientation

Consequences:

• Loss of correction

• Nonunion

• Reoperation

5. Joint Line Obliquity (JLO) Malalignment

• JLO outside 177°–183° range
  → altered knee biomechanics

Results:

• Poor functional outcomes

• Increased joint loading

• More challenging future TKA

6. Neglecting the Patellofemoral Joint

• Unrecognized PF degeneration → persistent anterior knee pain

• MOW may lead to patella baja, worsening PF symptoms

7. Incorrect Indications

• Tricompartmental OA → poor outcomes

• Advanced OA (KL ≥4) → limited benefit

• Inflammatory arthritis → continued disease progression

8. Underestimating Biological Factors

• Smoking → delayed union / nonunion

• Osteoporosis → compromised fixation stability

9. Technical Errors

• Inadequate fixation → loss of correction

• Large opening wedge without graft → nonunion

• Skipping fibular osteotomy in LCW → technical complications

10. Poor Future TKA Planning

• Excessive correction

• Residual abnormal JLO

Leads to:

• Technically demanding TKA

• Need for stemmed implants

• Higher complication rates

References:

1. Loke, R. W. K., et al. (2025). "Conversion to Total Knee Arthroplasty After High Tibial Osteotomy: A Systematic Review and Meta-analysis." The Orthopaedic Journal of Sports Medicine.

2. Herman, B. V., & Giffin, J. R. (2016). "High tibial osteotomy in the ACL-deficient knee with medial compartment osteoarthritis." Journal of Orthopaedics and Traumatology.

3. Chen, X., et al. (2020). "Higher risk of revision in total knee arthroplasty after high tibial osteotomy: a systematic review and updated meta-analysis." BMC Musculoskeletal Disorders.

4. Efe, T., et al. (2011). "Closing-wedge high tibial osteotomy: survival and risk factor analysis at long-term follow up." BMC Musculoskeletal Disorders.

5. Dal Fabbro, G., et al. (2024). "High survivorship rate and good clinical outcomes after high tibial osteotomy in patients with radiological advanced medial knee osteoarthritis: a systematic review." Archives of Orthopaedic and Trauma Surgery.

6. Kim, J.-H., Kim, H.-J., & Lee, D.-H. (2017). "Survival of opening versus closing wedge high tibial osteotomy: A meta-analysis." Scientific Reports.

7. Maniar, A. R., et al. (2026). "Improved clinical outcomes when maintaining a neutral joint line obliquity at high tibial osteotomy and subsequent total knee arthroplasty." Journal of Experimental Orthopaedics.