Objective To evaluate the effectiveness of open wedge high tibial osteotomy (OWHTO) in treatment of medial unicompartmental knee osteoarthritis (MUKOA). Methods A clinical data of 61 cases with MUKOA who were treated with OWHTO between January 2015 and January 2017 were retrospectively analyzed. There are 14 males and 47 females with an average age of 52.8 years (mean, 44-60 years). The body mass index ranged from 19.1 to 34.7 kg/m2 (mean, 25.3 kg/m2). Twenty-seven cases were left side and 34 cases were right side. The disease duration was 1-9 years (mean, 5.3 years). The MUKOA was rated as stage Ⅱ in 33 cases and stage Ⅲ in 28 cases. Preoperative Hospital for Special Surgery (HSS) score was 56.0±3.7. Walking visual analogue scale (VAS) score was 4.6±1.0. Results The operation time was 49-85 minutes (mean, 66.5 minutes). The length of incision was 10-13 cm (mean, 11.0 cm). The total overt blood loss was 80-210 mL (mean, 139.1 mL). The postoperative bed-rest time was 1-10 days (mean, 4.7 days). All patients were followed up 12-24 months (mean, 17.3 months). The bearing area of tibial platform at 3 months after operation was 60.3%-66.8%, with an average of 63.4%. At 3 and 6 months after operation, the HSS score was 79.1±4.2 and 85.3±3.1 respectively, and the VAS score was 1.7±0.7 and 0.6±0.5 respectively, all showing significant differences (P<0.05). Conclusion OWHTO is an ideal choice for treating MUKOA with less postoperative complications. The force line could be corrected by OWHTO. However, the preoperative preparations are very important, especially that the open angle should be measured accurately.
ObjectiveTo summarize the related research results of open wedge high tibial osteotomy (OWHTO) complicated with lateral hinge fracture. MethodsTo review the relevant literature of OWHTO at home and abroad in recent years and summarize and analyse the clinical experience. ResultsThe lateral hinge rupture may occur during the OWHTO, which may lead to the loss of correction angle after operation, delayed healing or non-union of osteotomy and so on. The lateral hinge plays an important role in the stability of the osteotomy. During the operation, the " safe zone” internal osteotomy can be used to protect the bone. Once the lateral hinge breaks, the TomoFix plate can be used to obtain the sufficient stability. For patients with lateral hinge rupture, functional exercise and full weight loading time should be guided by hinge breakage classification. ConclusionThe intact lateral hinge is beneficial to the healing and rehabilitation of OWHTO. The lateral hinge should be paid enough attention by clinicians.
The use of a filling block can improve the initial stability of the fixation plate in the open wedge high tibial osteotomy (OWHTO), and promote bone healing. However, the biomechanical effects of filling block structures and materials on OWHTO remain unclear. OWHTO anatomical filling block model was designed and built. The finite element analysis method was adopted to study the influence of six filling block structure designs and four different materials on the stress of the fixed plate, tibia, screw, and filling block, and the micro-displacement at the wedge gap of the OWHTO fixation system. After the filling block was introduced in the OWHTO, the maximum von Mises stress of the fixation plate was reduced by more than 30%, the maximum von Mises stress of the tibia decreased by more than 15%, and the lateral hinge decreased by 81%. When the filling block was designed to be filled in the posterior position of the wedge gap, the maximum von Mises stress of the fixation system was 97.8 MPa, which was smaller than other filling methods. The minimum micro-displacement of osteotomy space was –2.9 μm, which was larger than that of other filling methods. Compared with titanium alloy and tantalum metal materials, porous hydroxyapatite material could obtain larger micro-displacement in the osteotomy cavity, which is conducive to stimulating bone healing. The results demonstrate that OWHTO with a filling block can better balance the stress distribution of the fixation system, and a better fixation effect can be obtained by using a filling block filled in the posterior position. Porous HA used as the material of the filling block can obtain a better bone healing effect.