Is the High Tibial Osteotomy (HTO) Still a Valid Method for Treatment of Medial Unicompartmental Knee Osteoarthritis?

The history of proximal fibular osteotomies for medial compartmental knee osteoarthritis is long. Its beginnings reach the 1950s, when JP Jackson published a study on the treatment results [1]. In the following years, various authors published on the topic, describing positive clinical results for the corrective osteotomies of the knee. These provided burdening relief of the affected part of the knee joint due to the change in the mechanical axis of the limb. The overload was the main source of complaint and caused increasing physical disability [2,3]. As surgeons gained experience, they introduced a series of modifications to the operative techniques, while new technologies allowed for their implementation [4,5]. Open wedge high tibial osteotomies (HTO) became particularly popular thanks to their relatively simple operative technique. The first attempts were encumbered by various intra-operative complications, the most common of which were the fractures of the lateral tibial plateau or the lateral bony hinge. According to the literature, their frequency varied between 11 and 25% [6,7]. Usually, this required unexpected long-term immobilization in the form of a cast or a rigid brace, or a weeks-long limitation of weightbearing that necessitated the use of crutches and orthoses. These were supposed to secure the achieved correction until efficient bone tissue formed. Further inconveniences consisted of the unstable forms of the fragments fixations. Additionally, the hardware required removal in a repeated operative intervention after the bones healed. In order to accelerate the restoration of the osteotomy area and to achieve efficient bone healing, surgeons filled the open space between fragments with bony allo- or autografts. Recent years have brought about a significant deepening in the knowledge of the causes of adverse intra- and post-operative events. The techniques involved in the cutting methods of the proximal part of the tibia, the positioning of the bony hinge for the opening space of the fragments, as well as the methods for opening of the cut line and filling the empty spaces have significantly decreased the primary complications observed. Surgeons today know the localization of the tensions of the inner bone structure in the lateral tibial condyle and have established ways to avoid their fracture through the partial resection of the fibula in its proximal part. Thanks to that, we may protect the patients from severe complications caused by the fractures in the lateral column of the tibia.

The fixation of bony fragments through the stable setting of size-appropriate wedges made of biodegradable materials is the next step in the development of treating the early, unicompartmental forms of knee arthroses [8]. The paper ‘Open-wedge HTO with absorbable β-TCP/PLGA spacer implantation and proximal fibular osteotomy for medial compartmental knee osteoarthritis: New technique presentation’ presents this method. Similar filling methods of the open wedge of the osteotomy space were presented earlier using of tricalcium phosphates spacers. They required, however, additional stabilization with plates or other fixators [9]. In addition, due to its osteoinductive properties and the stable anchoring on the cut surfaces of the tibia described in the paper, the method relieves from the need to use bone grafts and other forms of stabilizing of bony fragments. Thanks to this solution, one avoids the need to collect bone grafts from the iliac crest or from alien grafts from the tissue bank. The option to undertake early weight-bearing of the operated limb is possible because tibial fragments have axial stabilization, instead of non-axial stabilization, achieved through plate fixation. Additionally, the patient avoids a further intervention to remove the hardware thanks to the biodegradability of the implant. If the general practitioners and rheumatologists cooperate well, there is an opportunity to select a significant number of patients with early forms of unicompartmental knee arthroses. This group, encouraged by the small scale of the operative intervention and the fast pace of return to ability, can achieve significant deferment or definite prevention of early total knee arthroplasty. The long-term high tibial osteotomy results presented by Saphan et al. and the low percentage of later conversion of the HTO to total knee arthroplasty encourages in favor of the presented operative techniques [10].

Disclosure statement

The authors have no competing interests to declare.