In medial opening wedge high tibial osteotomy (MOWHTO), even small, unintended changes in the posterior tibial slope (PTS) or patellar height can have major biomechanical consequences.
An increased PTS may overload the anterior cruciate ligament (ACL) or cause excessive anterior tibial translation, while a lowered patella (patella baja) can impair patellofemoral tracking and compromise future arthroplasty options. This paper outlines a refined MOWHTO technique designed to maintain both sagittal alignment and patellar height—preserving the knee’s native biomechanics and joint-preserving benefits.
Study at a glance: a technique-focused radiographic evaluation
The study reviews outcomes of patients undergoing MOWHTO with a focus on radiological precision and functional recovery.
Radiographic measurements were taken pre- and post-operatively, including:
- Posterior tibial slope (PTS)
- Caton-Deschamps Index (CDI) for patellar height
- Hip-Knee-Ankle (HKA) angle for coronal correction
Patients were followed clinically with KOOS and UCLA activity scores. The technique employed a controlled biplanar opening wedge, maintaining a slightly larger posterior gap and correct hinge axis alignment to avoid slope increases.
Key results: anatomical control of slope and height achieved
- Posterior tibial slope remained unchanged post-operatively, confirming precise hinge placement and balanced anterior-posterior opening.
- Patellar height was also preserved — avoiding the common complication of patella baja associated with large anterior wedge openings.
- Functional outcomes (KOOS, UCLA) improved significantly, with no trade-off between correction accuracy and knee mechanics.
- The results validate that maintaining posterior gap ratio and preserving tibial slope should be core principles of any MOWHTO procedure.
Clinical insights for surgeons: mastering the sagittal dimension
Surgeons performing MOWHTO must remember that alignment correction is three-dimensional — sagittal control is as vital as coronal accuracy.
- Keep the posterior gap slightly larger than the anterior one to prevent slope increase.
- Maintain hinge integrity at the correct mediolateral position.
- Evaluate both tibial slope and patellar height during planning and follow-up.
These steps help maintain natural kinematics, prevent excessive ACL tension, and optimise long-term outcomes.
Take-home messages
- Proper gap geometry and hinge management are key to preserving PTS and patellar height.
- A well-executed MOWHTO can achieve precise coronal correction without disturbing sagittal balance.
- Incorporating slope-control principles enhances outcomes and prolongs joint longevity.
Link to full paper: Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy
