2015 ISAKOS Biennial Congress ePoster #1718

Comparison of Results of Medial Opening-Wedge High Tibial Osteotomy With and Without Subchondral Drilling

Jae-Heon Jeong, MD, Seoul, Seoul KOREA, REPUBLIC OF
Woonhwa Jung, MD, Changwonsi, Gyeongnam KOREA, REPUBLIC OF
Department of Orthopaedic Surgery of Murup Hospital, Changwon-si, Gyeongnam , KOREA

FDA Status Cleared

Summary: Subchondral drilling had no effect on the outcome at 2 years after MOWHTO. In addition, there was no significant difference in the formation of fibrocartilage with or without subchondral drilling. Therefore, subchondral drilling is not necessary after MOWHTO.

Abstract:

Purpose

The purpose of this study was to compare the results of medial opening-wedge high tibial osteotomy with and without subchondral drilling. Second-look arthroscopy at 2 years postoperatively was used to assess the formation of fibrocartilage in both groups.

Methods

Patients were divided into two groups. Thirty knees who were treated with osteotomy and subchondral drilling (Group I) and 31 knees treated with osteotomy alone (Group II). Clinical evaluations were performed by use of Knee Society scores preoperatively and at 2 years postoperatively. For evaluation of cartilage degeneration, the International Cartilage Repair Society grading system was used for arthroscopic grading on initial arthroscopy during high tibial osteotomy. The patients underwent a second-look arthroscopic evaluation of the articular cartilage at the time of removal of the plate, an average of 2 years after the initial osteotomy. For evaluation of formation of fibrocartilage on second-look arthroscopy, the articular cartilage was classified either as having no change from initial surgery (Grade I) or if white scattering with fibrocartilage, partial coverage with fibrocartilage or even coverage with fibrocartilage (Grade II). Also, maturation of the appearance of the cartilage was defined. The appearance was mature if the chrondral defects were evenly covered with fibrocartilage. It was considered immature if there was white scattering or only partial coverage with fibrocartilage.

Results

In group I, the mean Knee Society knee score and function score were 67.3 ± 8.2 and 66.5 ± 14.3, respectively, preoperatively. At 2 years postoperatively, they improved to 91.2 ± 6.4 and 92.8 ± 10.0, respectively (P = .001 and P = .001, respectively). In group II, the mean Knee Society knee score and function score were 63.7 ± 13.9 and 66.8 ± 9.1, respectively, preoperatively. At 2 years postoperatively, they improved to 92.5 ± 5.3 and 92.2 ± 8.0, respectively (P =.001 and P = .001, respectively). There were no significant differences in the postoperative Knee Society knee score and function score at follow-up two year between the groups (p=0.389, 0.806, respectively). Grade II regeneration was achieved in the medial femoral condyle articular cartilage in 100 % of knees in group I and 94 % of knees in group II (P=0.492). Maturation of the cartilage was found in the medial femoral condyle articular cartilage in 10 % of knees in group I and 3 % of knees in group II (P=0.354). There was no significantly difference of the formation of fibrocartilage between the groups.

Conclusions

Subchondral drilling had no effect on the outcome at 2 years after MOWHTO. In addition, there was no significant difference in the formation of fibrocartilage with or without subchondral drilling. Therefore, subchondral drilling is not necessary after MOWHTO.