2017 Volume 36 Issue 4 Pages 427-433
Background: We have developed a novel fixation system (TriS Medial HTO Plate System®; Olympus Terumo Biomaterials, Japan) for medial open-wedge high tibial osteotomy (OWHTO). The purpose of this study was to clarify the short-term clinical outcome of OWHTO using TriS plates.
Methods: Fifty consecutive patients (54 knees) who underwent OWHTO with a locking plate (TriS plate) were enrolled in this study between 2014 and 2016, inclusive. Inclusion criteria involved patients who had persistent pain due to medial osteoarthritis or spontaneous osteonecrosis of the knee. There were 31 women and 19 men with a mean age of 61.7 (36-78) years at the time of surgery. Intraoperatively, we performed a biplanar osteotomy of the tibia. Beta-tricalcium phosphate spacer (Osferion 60®, Olympus Terumo Biomaterials, Japan) was implanted in the opening space. Following that, the TriS plate was implanted onto the tibia. All patients underwent clinical, radiological, and computed tomography evaluations before surgery and at six months after surgery.
Results: Postoperatively, the mean Japan Orthopaedic Association score significantly improved from 68.9 to 89.0 points (P<0.001). At the final examination, the lateral femorotibial angle changed from 180.2 degrees to 169.7 degrees. The weight-bearing line percentage shifted to pass through a point 69.1% lateral from the medial edge of tibial plateau. The Insall-Salvati ratio and the mean posterior slope did not significantly change after surgery. The following complications occurred; one case of superficial wound infection (1.9%) and seven cases (13.0%) of lateral hinge fracture: six cases of type Ⅰ, and one case of type Ⅲ according to Takeuchi’s classification. There were no severe complications, such as pseudoarthrosis or deep surgical site infection.
Conclusions: Using the TriS plate system, the medial knee pain resolved in all cases. This study demonstrates that the TriS plate is a useful system for medial OWHTO procedures.
