The Tibia Plafond Horizontal Orientation Angle for Frontal Alignment Evaluation of the Distal Lower Extremity

Area of Science:

• Orthopedic Surgery
• Radiology
• Biomechanics

Background:

• Knee osteotomies are used to treat knee osteoarthritis by redistributing weight.
• Accurate assessment of lower limb alignment is critical for successful surgical outcomes.

Purpose of the Study:

• To evaluate the reliability of the Tibia Plafond Horizontal Orientation Angle (TPHA) for assessing distal tibia coronal plane alignment.
• To determine the clinical utility of TPHA in the context of knee osteotomies.

Main Methods:

• Retrospective analysis of 146 patients undergoing supracondylar rotational osteotomies.
• Collection of five radiographic variables: mLDTA, mMA, MHA, TPHA, and TTTA.
• Comparison of preoperative and postoperative measurements using the Wilcoxon signed rank test.

Main Results:

• TPHA showed a significant decrease postoperatively (p = 0.013), indicating a reliable change.
• The change in TPHA correlated significantly with the change in Malleolar Horizontal Orientation Angle (MHA) (p = 0.025).
• No significant preoperative-to-postoperative changes were observed for mLDTA and mMA.

Conclusions:

• TPHA is a dependable metric for evaluating distal tibial alignment in the frontal plane.
• Ankle orientation assessment, including TPHA, is recommended for preoperative planning and evaluating postoperative ankle discomfort following knee osteotomies.