Validation of a Stress Device for the Knee

X-rays are the most frequently used imaging test when evaluating the knee for joint replacement. They are non-invasive, safe and cost effective. They allow assessment of: progression of disease, appropriateness for joint replacement (in particular unicompartmental knee replacement (UKR)) as well as likely prognosis following replacement. Currently standard assessment involves: standing anteroposterior, lateral and skyline X-ray views. In addition in patients being considered for joint replacement valgus/varus stress X-rays are used to evaluate the lateral compartment (as well as medial collateral ligament) and medial compartment respectively to assess the status of the cartilage. Stress X-rays require the clinician to attend X-ray, often during busy clinics, exposing them to additional radiation, and as such they are seldom performed. A patient and user friendly device for performing valgus and varus stress X-rays of the knee for diagnostic and pre-operative planning purposes in the setting of knee replacement surgery has been developed. This device has the potential to benefit patients as it will allow an accurate assessment of the pattern and severity of arthritis affecting their knee without the need for additional diagnostics such as MRI or arthroscopy. Furthermore for healthcare practitioners and providers this device will facilitate the smooth running of clinics and reduce the additional clinic appointments required to review MRI results. Ultimately this device will allow an informed discussion about treatment options, reduce the pre-operative uncertainty about suitability for UKR in those undergoing surgery and ensure that those patients who are suitable for UKR benefit from this procedure. This device will help ensure that patients receive the optimum treatment in a clinically and cost efficient manner. This study will validate valgus and varus stress X-rays performed using the investigators' device against the gold standard of clinician performed manual stress.