Tibial slope changes following dome-type high tibial osteotomy

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Knee Joint Anatomy

Background:

• The tibial slope is crucial for knee biomechanics, affecting ligament function and kinematics.
• High tibial osteotomy (HTO), used for frontal plane malalignment in knee osteoarthritis, can unintentionally alter the tibial slope.

Purpose of the Study:

• To evaluate changes in tibial slope after dome-type HTO in patients with medial compartment osteoarthritis.
• To analyze the relationship between frontal plane correction and sagittal plane (tibial slope) changes.

Main Methods:

• Prospective evaluation of 40 knees treated with dome-type HTO and external fixation.
• Measurement of tibial slope using four methods (anterior tibial cortex, proximal tibial anatomic axis, posterior tibial cortex, proximal fibular anatomic axis) preoperatively and postoperatively.
• Classification of patients into hypercorrection, normocorrection, and undercorrection groups based on final frontal plane alignment.

Main Results:

• A significant decrease in tibial slope was observed postoperatively across all measurement methods.
• Undercorrection of frontal plane deformity resulted in a more pronounced tibial slope decrease.
• A positive correlation was found between the degree of postoperative mechanical axis valgus and the resulting posterior tibial slope.

Conclusions:

• Dome-type HTO generally leads to a decrease in tibial slope.
• These sagittal plane changes should be considered in planning future reconstructive procedures, such as total knee arthroplasty.