Change of the Patellar Height and Tibial Inclination after Opening- and Closing-Wedge High Tibial Osteotomy

Cho, Se Hyun; Hwang, Sun Chul; Park, Jin Sung; Lee, Sang Hyuk

Abstract

PURPOSE: We wanted to evaluate the patella height, the tibial inclination and the joint height changes after closing-wedge high tibial osteotomy (CW HTO) and opening-wedge high tibial osteotomy (OW HTO).
MATERIALS AND METHODS
The lateral radiographs taken with 30degrees flexion of the knees for 46 CW HTOs and 32 OW HTOs were assessed regarding the patellar height by the Insall-Salvati index (ISI) and the Blackburne-Peel index (BPI) and for the tibial inclination by the Moore-Harvey (MH) method. The average follow up period was 3.6 years (range: 2.0 to 4.7 years). Spearman correlation analysis was used to determine the influence of the two types of HTO with the amount of correction in the frontal plane Hip-Knee-Ankle (H-K-A) axis. The joint height was measured between the fibular head and the lateral tibial plateau. Measurements were made at the preoperative, postoperative and final follow-up periods.
RESULTS
In the CW group, both the ISI and BPI were increased at the postoperative and final follow-up periods, while the BPI showed a statistically significant increase (p=0.046). In the OW group, both the ISI and BPI were decreased, while the BPI showed a statistically significant decrease (p=0.007). There was a tendency of a decrease of the tibial inclination in the CW HTO group without statistical significance. But in the OW HTO group, there was a statistically significant increase of the tibial inclination (p=0.012). The frontal plane H-K-A axis correction did not influence the change of the patellar height and tibial inclination in both groups (r<0.3). The joint height measured between the fibular tip and the lateral tibial plateau showed a significant decrease in the CW group (p=0.000), while there was no significant change in the OW group.
CONCLUSION
The anatomical alteration of the patellar height was significantly influenced in opposite ways by the two methods of HTO. The BPI was more statistically significant then the ISI for the measurement of the patellar height after HTO. The joint height was significantly decreased in the CW HTO group. These changes should be kept in mind when converting HTO to total knee arthroplasty.