Precision of Pacient-specific Instrumented Open Wedge High Tibial Osteotomy vs Conventional Technicque

Medial opening wedge high tibial osteotomy is a well-established surgical procedure to correct knee alignment in patients with medial knee osteoarthritis and varus deformity. The accuracy of the bone cut is critical for surgical success. However, conventional techniques performed with anatomical landmarks and fluoroscopy may result in variability and suboptimal correction.

Recent advances in 3D imaging and printing allow the creation of patient-specific surgical guides designed from preoperative CT scans. These guides may improve the accuracy and reproducibility of the osteotomy.

This single-center randomized clinical trial will include 50 adult patients, randomly assigned to undergo conventional osteotomy or osteotomy assisted by patient-specific instrumentation. The main outcome is the accuracy of the osteotomy cut compared with preoperative planning. Secondary outcomes include leg alignment, surgical efficiency, radiation exposure, complications, and functional recovery. Patients will be followed for 12 months.

Inclusion criteria

• Informed consent: able to sign informed consent
• Clinical: predominantly medial pain/limitation refractory ≥3-6 months
• Mobility: flexion ≥90º and flexion contracture ≤10º Stability: varus/valgus and pivot-shift ≤ grade 1.
• Radiology:

• Medial gonarthrosis Ahlbäck I-III with preserved lateral compartment.
• Patellofemoral Iwano 0-2 without disabling patellofemoral pain.
• Varus alignment: HKA 4-10°.
• Predominantly tibial deformity (decreased MPTA; LDFA close to normal) according to planning.
• Anatomy/technical feasibility: proximal tibial morphology suitable for medial opening osteotomy and PSI guide placement.

Exclusion criteria

• Comorbidity/clinical situations:

• Inflammatory arthritis (e.g., RA, spondyloarthropathies), unresolved previous joint infection or osteomyelitis.
• Severe peripheral vasculopathy (ABI <0.7), advanced peripheral neuropathy or Charcot foot.
• Poorly controlled diabetes (HbA1c >8.5%), advanced renal/hepatic failure (eGFR <30 ml/min/1.73 m²; Child-Pugh B/C).
• Smoking >20 cigarettes/day without commitment to cessation; active IV drug use or uncontrolled alcoholism.
• BMI >35 kg/m².
• Disorder affecting gait (e.g., neurological disease).
• Inability to walk at a speed of at least 0.8m/s
• Anatomy/radiology

• Multiplanar deformities not correctable with isolated medial opening tibial valgus osteotomy (e.g., dominant femoral deformity).
• Severe medial subchondral bone defect or extensive necrosis.
• Sequelae of proximal tibia fracture or previous ipsilateral HTO that prevent correction or guide use.
• Treatments/medication and logistics

• Anticoagulation/antiplatelet therapy that cannot be suspended or bridged.
• Systemic corticosteroids >10 mg/day or high-risk immunosuppressants without possibility of adjustment.
• Intra-articular infiltration (HA/CS/PRP) within the previous 60 days (respect defined wash-out).
• Pregnancy.
• Participation in another interfering trial.
• Inability to undergo CT (e.g., uncontrollable claustrophobia).
• Inability to complete ≥12 months of follow-up.