2023 ISAKOS Biennial Congress ePoster
Medial Closed-Wedge Distal Femoral Varus Osteotomy Improves Patellofemoral Joint Congruity
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 Cleared
Summary
Our data suggested that Medial Closed-Wedge Distal Femoral Varus Osteotomy effectively improved the congruity of the PF joint in valgus deformity.
ePosters will be available shortly before Congress
Abstract
Objective
Distal femoral varus osteotomy (DFVO) is a well-described treatment option for patients with valgus malalignment. Biomechanical studies have confirmed the role of DFO in unloading the lateral compartment and correcting the mechanical axis of the lower limb. The most commonly studied diagnosis has been isolated lateral compartment osteoarthritis in the physiologically young, active patient. Systematic review reported that no evidence exists proving better results of either the medial closing wedge (CW) or the lateral opening wedge (OW) techniques. Previous studies reported that it may be a useful concomitant procedure in young patients with lateral meniscus deficiency, focal chondral defects in lateral compartment, and/or patellofemoral (PF) instability. DFO reduces the Q angle and medializes the tibial tubercle, which unloads the PF compartment laterally and may improve patellar tracking, thereby decreasing PF pain and instability in select patients. However, change in PF congruity after MCW-DFVO remains unclear. The purpose of this study was to evaluate the changes of the PF joint congruity following MCW-DFVO.
Methods
Twenty patients(23knees) who underwent MCW-DFVO for lateral compartment OA spontaneous osteonecrosis of the knee (SONK) with valgus knee from 2016to2020 were enrolled prospectively in this study. There were 2men and 18women with a mean age of 42(14 to 75) years at the time of surgery. The indication for the MCW-DFVO procedure was symptomatic, isolated lateral compartment OA knees or SONK with valgus deformity. Clinical and radiological evaluations were performed in all cases before surgery and at the final follow-up (12to62 months). 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 (Japanese Orthopedic Association score) and Lysholm score significantly improved at the final follow-up (p<0.001). The correction angle averaged 7.0°varus. Postoperatively, the hip-knee-ankle angle (HKA) significantly changed from 6.3° to -1.9° (p<0.001). The lateral femorotibial angle (FTA) significantly changed from 168.2° to 176.6° (p<0.001). The mechanical axis (%MA) significantly changed from 74.6% to 38.0% (p<0.0001). The mechanical lateral distal femoral angle (LDFA) significantly changed from 81.7° to 89.4° (p<0.0001). Concerning the patella height, there were no significant differences in the Caton-Deschamps (CD) index between the 2 periods. Regarding the PF joint congruity, the tilting angle significantly decreased from 7.5° to 5.5° after surgery (p<0.0001). The lateral shift ratio significantly decreased from 18.3% to 14.0% (p<0.0001). The mean femoral anteversion was significantly decreased from 23.2° to 21.8° (p<0.0001). The tibial tuberosity-trochlear groove (TT-TG) distance significantly decreased from 14.6 mm to 11.8 mm (p=0.0004).
Discussion
This study clearly demonstrated that postoperative clinical scores significantly improved after MCW-DFVO. The valgus malalignment was significantly corrected to mild varus alignment. Regarding postoperative PF joint, the tilting angle significantly decreased, and the lateral shift ratio showed significant medial translation at the final follow-up compared with the preoperative value. The reduction of PF congruity suggested that this osteotomy might decrease the contact pressure on the lateral PF joint by decreasing the Q angle, TT-TG distance, and femoral anteversion. Recent clinical studies reported that MCW-DFVO is a suitable treatment for patellar instability and mal-tracking due to genu valgum. Our data suggest that MCW-DFVO effectively improved the congruity of the PF joint in valgus deformity.