Difference in Correction Power between Hybrid Lateral Closed-Wedge High Tibial Osteotomy and Medial Open-Wedge High Tibial Osteotomy was Associated with Severity of Varus Deformity and Different Hinge Distance from Center of Deformity

Abstract

Hybrid lateral closed-wedge high tibial osteotomy (HBHTO) carries certain advantages over medial open-wedge high tibial osteotomy (OWHTO). We investigated the potential difference in the required correction angle between HBHTO and OWHTO to achieve an equal amount of whole lower-extremity alignment correction, retrospectively analyzing the preoperative plain radiographic images of 100 patients. The medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), mechanical lateral distal femoral angle (mLDFA), hip-knee-ankle axis (HKA), length of the tibia, width of the tibial plateau, length of the lower limb (leg length), and location of the center of deformity (CD) were measured. Differences in the required correction angle at the hinge point between the two techniques (CAD) were compared, and correlation analysis was performed to reveal the influential factors. The mean difference in CAD between HBHTO and OWHTO was 0.78 ± 0.22 (0.4~1.5)°, and mean WBL position change per correction angle was 3.9 ± 0.3 (3.0~4.6)% in HBHTO and 4.1 ± 0.3 (3.1~4.7)% in OWHTO. Correlation analysis revealed a strong positive correlation between CAD and HKA. mLDFA, JLCA, MPTA, leg length, OWCD, HBCD, and HCD were also significantly correlated with CAD. HBHTO required a 5.6% larger correction angle at the hinge point to achieve the same amount of alignment correction as OWHTO.

Keywords: knee; osteoarthritis; osteotomy; retrospective study; tibia.

Figure 1

CONNECTEVE-X software was used to assess radiological parameters.

Figure 2

Center of deformity was designated as a crossing point between mechanical axis of the femur and tibia. Hinge points and correction angles were designated using Miniaci method. (A) Identification of center of deformity in the long standing radiograph (B) Designation of OWHTO plan based on the hinge point 10 mm distal to the lateral tibial plateau and 10 mm medial to the lateral proximal tibial cortex (C) Designation of HBHTO plan based on the hinge point located on the osteotomy line one-third from the medial tibial cortex (D) Relationship between center of deformity and two different hinge points (E) Distance from HBHTO hinge point to center of deformity was defined as HBCD and one from OWHTO hinge point to center of deformity was defined as OWCD; In case of highest CD position (A1–E1); high CD position(A2–E2); low CD position(A3–E3).

Figure 3

Difference in required correction angle tends to increase according to increasing hip–knee–ankle axis.

Figure 4

Correlation analysis between alignment parameters and CAD. **: The correlation is significant at the 0.01 level (both sides).

Figure 5

Correlation analysis between distance parameters and CAD. Correlation coefficient 0.000~0.250. *: The correlation is significant at the 0.05 level (both sides). **: The correlation is significant at the 0.01 level (both sides).

Figure 6

Distribution of CAD between different CD positions.