Custom knee surgery aims for better alignment in osteoarthritis patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patients undergoing High Tibial Osteotomy * Male or Female, aged 18 to 65 years * Primary diagnosis of Non-Inflammatory Degenerative Joint Disease (NIDJD) * Predominately diagnosed with unicompartmental medial osteoarthritis of the knee with the normal clinically acceptable level of other compartmental involvement * Varus deformity \<20 ° * BMI ≤ 35. An exemption to this may be made if the participant (in the investigators opinion) is suitable for surgery. * Participant is willing and able to give informed consent for participation in the study. * Able (in the Investigators opinion) and willing to comply with all study requirements. * Willing to allow his or her General Practitioner and consultant, if appropriate, to be notified of participation in the study. Exclusion Criteria: * Female participants who are pregnant, lactating or planning pregnancy during the course of the study. * Prisoners * Participants with a known deep tissue sensitivity to device materials * Participants with an active or suspected latent infection in or about the affected knee joint * Participants who have received any orthopaedic surgical intervention to the lower extremities (excluding investigative surgery) within the past 12 months, or is expected to require any orthopaedic surgical intervention to the lower extremities, other than the HTO to be enrolled in this study, within the next 12 months (including intra-articular procedures). * Participants who require bilateral HTO with surgery planned on their second knee within 6 months of their first operation (bilateral HTO patients are otherwise included). * Participants who require bilateral HTO who have had a previous unsuccessful contralateral partial replacement or HTO * Chronic heart failure (NYHA Stage ≥ 2) * Neuromuscular or neurosensory deficiency, which limits the ability to evaluate the safety and efficacy of the device * Systemic disease diagnosis (e.g. Lupus Erythematosus) or a metabolic disorder (e.g. Paget's disease) leading to progressive bone deterioration. * Participant is immunologically suppressed or receiving steroids in excess of normal physiological requirements (e.g. \> 30 days). * Participant is a smoker. * Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study.