2023 ISAKOS Biennial Congress ePoster
The Effect Of Medial Closing Wedge Distal Femoral Varus Osteotomy On Contact Stress Distribution Pattern Of The Femorotibial Joint
Masanari Hamasaki, MD,PhD, Sapporo, Hokkaido JAPAN
Eiji Kondo, MD, PhD, Sapporo, Hokkaido JAPAN
Koji Yabuuchi, MD, Muroran, Hokkaido JAPAN
Koji Iwasaki, MD, PhD, Sapporo, Hokkaido JAPAN
Yuki Suzuki, MD, PhD, Sapporo JAPAN
Masatake Matsuoka, PhD, Sapporo JAPAN
Tomohiro Onodera, MD, PhD, Sapporo, Hokkaido JAPAN
Kazunori Yasuda, MD, PhD, Prof., Sapporo, Hokkaido JAPAN
Tomonori Yagi, MD, PhD, Sapporo, Hokkaido JAPAN
Norimasa Iwasaki, MD, PhD, Sapporo, Hokkaido JAPAN
Hokkaido University, Sapporo, Hokkaido, JAPAN
FDA Status Not Applicable
Summary
By an evaluation using computed tomography osteoabsorptiometry, our research indicated medial closing wedge distal femoral varus osteotomy shifted the stress distribution pattern of the lateral compartment of the proximal tibia articular surface toward the medial compartment.
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Abstract
Introduction
Distal femoral varus osteotomy (DFVO) is a well-described treatment option for patients with valgus malalignment associated with a broad range of knee disorders. Previous studies reported that medial closing wedge - DFVO (MCW-DFVO) may be a useful concomitant procedure in young patients with isolated lateral compartment osteoarthritis. However, how the distribution pattern of subchondral bone density changes on the articular surface across the knee joint after MCW-DFVO is yet to be elucidated. Our previous studies using Computed tomography (CT) osteoabsorptiometry evaluated stress distribution at each joint under various loading conditions by measuring subchondral bone density. The purpose of this study was to evaluate change in the pattern of subchondral bone density distribution of the femorotibial (FT) joint in patients with valgus knee before and after MCW-DFVO.
Methods
Thirteen patients (14 knees) who underwent MCW-DFVO for lateral compartment osteoarthritis (OA) with valgus knee from June 2016 to May 2021 were enrolled prospectively in this study. There were 1 man and 12 women with a mean age of 43 years (range; 14 to 73 years) at the time of surgery. Clinical and radiological evaluations were performed in all cases before surgery and at the final follow-up. The distribution patterns of subchondral bone density through the FT articular surface of tibia were assessed before and more than 1 years after the surgery using a CT osteoabsorptiometry method. The quantitative analysis of the obtained mapping data focused on location of the high density area (HDA) through the articular surface. The %HDA in each region was defined as HDA of each divided region by HDA of entire articular surface. In FT joint, the medial and lateral compartment of the proximal tibia was divided into each 4 subresions of equal width in the coronal direction, denoted M1 to M4 and L1 to L4 from the medial to lateral sides. Statistical analysis was made using a paired t test. The significance level was set at p=0.05.
Results
The mean postoperative functional knee score and Lysholm score significantly improved at the final follow-up (p<0.001 for each). The correction angle averaged 7.1° varus. Postoperatively, the Hip Knee Angle, Femoro Tibial Angle , mechanical axis, and mLatera Distal FAangle changed significantly (p<0.001) as compared with the preoperative values. In CT osteoabsroptiometry evaluation of FT joint, the %HDA in the M2, M3 and the M4 of the tibia were significantly increased after MCW-DFVO surgery (p=0.029, p=0.026, and p=0.003, respectively). The %HDA in the L2, L3 and L4 of the tibia were significantly decreased after MCW-DFVO surgery (p=0.031, p=0.043, and p=0.036, respectively).
Discussion
This study demonstrated that postoperative clinical scores significantly improve after MCW-DFVO. The valgus malalignment significantly corrected to mild varus alignment. Using CT osteoabsorptiometry methods, we investigated in vivo stress distribution patterns of the FT joint before and after MCW-DFVO. This study demonstrated that the MCW-DFVO procedure significantly increased stress distribution patterns of %HDA in the M2, M3 and M4, and decreased those of %HDA in the L2, L3 and L4. It indicated that MCW-DFVO shifted the stress distribution pattern of the lateral compartment of the proximal tibia articular surface toward the medial compartment.