Double level knee osteotomy using patient-specific cutting guides is accurate and provides satisfactory clinical results: a prospective analysis of twenty-two continuous patients

Correcting combined tibial and femoral deformity requires excellent accuracy to avoid residual malalignment or excessive joint line obliquity (JLO). A double level osteotomy (DLO) carries higher technical demands than single-level procedures, and alignment errors can have meaningful biomechanical consequences.
This study evaluates whether patient-specific cutting guides (PSCGs) can help surgeons perform DLO with greater precision and produce strong clinical outcomes.

Study design and methodology: cohort characteristics and technical workflow

This prospective single-centre study followed 22 consecutive patients undergoing DLO using PSCGs between 2014 and 2018.

Pre-operative planning established target values for:
• Hip-Knee-Ankle angle (HKA)
• Medial Proximal Tibial Angle (MPTA)
• Lateral Distal Femoral Angle (LDFA)
• Posterior Proximal Tibial Angle (PPTA)

PSCGs were produced from patient-specific imaging and used intra-operatively to guide both femoral and tibial cuts.

Clinical follow-up averaged ~2 years, with radiographic accuracy and KOOS outcome measures as the primary endpoints.

What the data revealed: alignment precision and clinical improvement

• Alignment accuracy was high across all parameters:
  
  • ΔHKA: 1.3 ± 0.5°
  • ΔMPTA: 0.98 ± 0.3°
  • ΔLDFA: 0.94 ± 0.2°
  • ΔPPTA: 0.45 ± 0.4°
    
• Joint line obliquity was very well preserved (mean change 0.4 ± 0.2°).
  
• KOOS improved significantly across all subdomains at final follow-up.
  
• Patient satisfaction was high: 19 “enthusiastic”, 2 “satisfied”, 1 “moderately satisfied”. These results support PSCG-assisted DLO as both highly precise and clinically beneficial in the medium term.

Clinical meaning: how surgeons can apply these findings

• PSCGs allow surgeons to achieve alignment values within ~1° of planned targets, which is excellent for multilevel correction.
  
• Preserving a near-physiologic joint line orientation (JLO) helps maintain more natural mechanical loading patterns.
  
• Functional improvements and satisfaction scores suggest precision translates into meaningful patient benefit.
  
• PSCGs may help reduce variability between surgeons and increase reproducibility of DLO—especially valuable for those performing fewer osteotomies annually.
  
• However, the study size is small (n=22), and longer-term (>5 year) results are still needed.

Key insights and real-world relevance

1. PSCGs enable highly accurate double level correction, achieving near-perfect execution of planned alignment.
   
2. Joint line orientation is reliably preserved, reducing the risk of pathological obliquity.
   
3. Clinical outcomes and patient satisfaction are strong at two years.
   
4. For complex malalignment cases, PSCGs may enhance both safety and reproducibility—particularly in centres performing high volumes of alignment surgery.
   

Link to full paper: Double level knee osteotomy using patient-specific cutting guides is accurate and provides satisfactory clinical results: a prospective analysis of twenty-two continuous patients

Sources used in report overview:

1. https://pubmed.ncbi.nlm.nih.gov/34536082/
2. https://link.springer.com/article/10.1007/s00264-021-05194-z
3. https://u1093.ube.fr/en/publication/double-level-knee-osteotomy-using-patient-specific-cutting-guides-is-accurate-and-provides-satisfactory-clinical-results-a-prospective-analysis-of-a-cohort-of-twenty-two-continuous-patients-3/