REC REF: 13/LO/1639


To determine whether a patient-matched cutting block is an accurate and reliable method of achieving planned deformity correction. Specifically, if this approach results in a final radiographic alignment that is within two degrees of the pre-operative plan in both sagittal and coronal planes.


Knee deformity

For people whose leg bones do not line up properly, extra stress is placed on either the inner or outer side of the knee joint due to uneven transfer of body-weight, gradually resulting in osteoarthritis. An operation exists whereby one of the bones either side of the knee is cut (an osteotomy) and hinged open to straighten the leg. This alteration redistributes body-weight more equally across the knee joint, and is known to be effective in delaying, and possibly preventing the progression of knee osteoarthritis. In patients with more advanced osteoarthritis, osteotomy is not an appropriate surgical intervention and a partial knee replacement is more preferable, with the aim to re-line the osteoarthritic part of the knee. Current methods used during these operations to determine whether the bone has been cut in the correct position potentially lack accuracy. To improve accuracy we propose the use of a custom-made ‘cutting block’, tailored for each individual patient.  The ‘patient-matched cutting block’ will be manufactured to meet individual needs, using three-dimensional imaging that is tailored to your leg, and your operation. It will contain slots and holes (the position of which will have been calculated by your surgeon at the planning stage, before the operation). These slots and holes will then guide your surgeon’s drill holes and bone cuts, and should ensure that your implant is positioned correctly.

This is an international multicentre study, primarily looking to examine whether there is a close match between the planned and actual correction of leg deformities when using a patient –matched cutting block.