The CISKO imaging study will assess whether there is a difference between the TomoFix and Ellipse system in terms of bone regeneration in the tibial wedge by performing a CT-scan at 3 and 6 months post-operatively. This will be quantified by two independent radiological reports. A secondary objective is to investigate patient satisfaction and also patient pain levels at these time intervals. The degree of bone healing is usually the main factor holding clinicians back when it comes to advising patients on what activities they can return to post-operatively. A difference in bone healing between the two systems may impact on the advice clinicians can give patients regarding recommencing more intense activities such as recreational sports, which ultimately could positively impact patients' health and well-being.