NitrX Total Knee Arthroplasty RSA

Model based Radiostereometric Analysis (RSA, specialized Xrays) will be used to register the location of the tibial implant components during supine and standing exams and measure implant movement. Changes throughout the different time points of potential tibial migration, with the use of the tibial bone beads, will be measured in millimeters.

Model based Radiostereometric Analysis (specialized Xrays) will be used to register the location of the femoral components during supine and standing exams and measure implant movement. Changes throughout the different time points of potential femoral migration, with the use of the femoral bone beads, will be measured in millimeters.

Model based Radiostereometric Analysis (specialized Xrays) will be used to register the location of the femoral and tibial components in both standing and supine exams where the minimum joint space width between components on the medial and lateral condyles can be calculated as a measurement (in millimeters) of polyethylene wear.

Patients will have blood drawn and the levels of circulating cobalt, chromium, and nickel will be measured in whole blood. One vial of blood will be drawn from the patient (in milliliters).

Patients will complete an MRI exam using metal artefact reduction sequences. Scans will be evaluated and scored for synovial inflammation and fibrosis, indicative of reactions to metal debris, and the presence of fibrous tissue at the bone-cement-implant interface, indicative of component loosening.

Patient reported outcome measure. Holds 42 items that asks patient about pain, functional daily living, and sport and recreation. Questionnaire measures levels in frequency (never to always) and severity (none to extreme). Scores are from 0-100, with higher scores indicating no knee problems.

Patient reported outcome measure observing the ability of a patient to forget about a joint due to successful treatment. Contains 12 items with frequency level measurement (never to mostly). The higher the score (0-100), the less aware the patient is of their affected joint when performing daily activity.

Patient reported outcome measure observing physical and mental health status of patient. Contains 14 items measuring levels of severity (excellent to poor) and frequency (None of the time to Yes, all of the time). Higher scores indicate higher quality of life and vice versa.

Patient reported outcome measure. Standardized 5 item instrument measuring generic health status of patient. The EQ5D uses a Likert scale which assesses five states (mobility, self care, usual care, pain and discomfort and anxiety and depression) at five different levels - none(0), slight(1), moderate(2), severe(3) or unable to perform(5). Levels are coded 1-5 and an index score is then generated. Higher scores indicate higher health status of patient.

Patient reported outcome measure. Screening tool for noting pre-operative environmental metal exposures. Questionnaire contains Yes or No questions. Higher scores would indicate greater exposure and/or metal sensitivity.