Tomofix plate

The surgical indication was medial knee arthritis accompanied by mild varus deformity found in weight bearing radiographic evaluation. In addition, we selected patients who had no osteophyte in the lateral compartment, who had reasonable joint space preservation and who had medial meniscus damage alone. Arthroscopy with microfracture was performed in each patient preoperatively and partial meniscectomy or suture was performed when medial meniscus damage was found. Surgeon pulled the torn meniscus with an arthroscopic probe and decided partial meniscectomy or suture.
A longitudinal skin incision was made on the medial side of the tibial tuberosity. The superficial medial collateral ligament was completely released below the osteotomy site. Biplanar medial open wedge osteotomy was performed using chronOS vivify spacer (DePuy Synthes, Solothurn, Switzerland) and TomoFix plate (DePuy Synthes). Target correction angle was measured at the point where the mechanical axis of the lower limb passed through the Fugisawa point, which is 62.5% from the medial tibial articular margin.

The target correction angle was measured on a long-standing hip-to-ankle radiograph with the patella facing forward, using the method described by Miniaci et al.²³
The target weightbearing point was adjusted from 62.5% from the medial border along the width of the tibial plateau, based on arthroscopic findings regarding the severity of degenerative changes in each compartment of the knee joint.^{7 (link)}
After partial detachment of the semitendinosus and gracilis tendons, the superficial medial collateral ligament was distally released below the osteotomy level. Biplanar osteotomy was performed until 9 mm of the intact lateral hinge remained. The proximal tibia was opened using a laminar spreader under intraoperative fluoroscopy and fixed with TomoFix plate (DePuy Synthes). A distal cortical screw was inserted in full extension of the knee joint. Weightbearing was gradually allowed from toe-touch during the first 2 weeks to full weightbearing at 6 to 8 weeks postoperatively.

After a diagnostic arthroscopy procedure, biplanar supracondylar lcwDFO^{34 (link)} or mowHTO^{14 (link)} was performed as previously described. For the biplanar mowHTO, first a bicortical frontal osteotomy was performed with an ascending or a descending osteotomy orientation, depending on the patellofemoral cartilage status.^{14 (link)} Next, 2 axial K-wires were positioned in an oblique direction toward the fibular head. For lcwDFO, the biplanar osteotomy planes were marked and an ascending bicortical frontal osteotomy was performed. Next, 4 axial K-wires marking the osteotomy wedge to be excised proximally and distally were placed for an axial osteotomy. Next, respective osteotomies preserving the contralateral cortex were performed with the hinge located at a 0.5- to 1-cm distance from the medial cortex. The osteotomy gap was carefully closed (lcwDFO) or opened (mowHTO), applying valgus stress and axial compression. To control for adequate mechanical correction, the osteotomy was fixed temporarily, and alignment was assessed via intraoperative hip-knee-ankle alignment fluoroscopy with an alignment rod^{8 (link)} and adjusted as needed. Consecutively, the osteotomy was secured with a locking compression plate, using either a Polyetheretherketone-Power plate (Arthrex) or a Tomo-Fix plate (DePuy Synthes).