Opening-wedge High Tibial Osteotomy (HTO) has been shown to be an effective procedure to treat mild to moderate osteoarthritis of the medial compartment of the knee in active individuals. It has also become a mandatory surgical adjunct to articular cartilage restoration when there is preoperative mal-alignment. However, its efficacy is directly correlated with the accuracy of the correction, which must be within 3° of the preoperative target. Achieving this goal is a significant challenge with conventional techniques. Therefore, computer-assisted navigation protocols have been developed; however, they do not adequately address the technical difficulties associated with this procedure. We present an integrated solution dedicated to the opening-wedge HTO. Advantages to the technique we propose include: 1) a minimum number of implanted bone trackers, 2) depth control of the saw, 3) improved 3-D accuracy in the location of the lateral tibial hinge, and 4) micrometric adjustment of the degree of correction. The proof of concept has been completed on all six specimens. The following key points have been validated: a) Compatibility with a minimally-invasive (5–6 cm) surgical incision b) The compact navigation station can be placed close to the operative field and manipulated through a sterile draping device c) Only two trackers are necessary to acquire the required landmarks and to provide 3-D control of the correction. These can be inserted within the surgical wound without any secondary incisions d) The optimised guide accurately controlled the external tibial hinge in all six cases e) The implant cavity could be milled effectively f) The distractor used to complete the desired realignment maintained stability of the distraction until final fixation with the PEEK implant g) The PEEK implant could be fixed to the tibia with excellent stability in a low-profile fashion. The solution presented here has the potential to help surgeons perform a medial opening-wedge HTO more safely and accurately. This will likely result in an increase in the number of HTOs performed for both isolated medial compartment osteoarthritis as well as for lower extremity realignment in association with cartilage restorative procedures.