RCT Comparing Functional Outcomes for Navigated Kinematically Aligned TKR Versus Navigated Mechanically Aligned TKR

STUDY DESIGN

1. .subject recruitment Patients will be recruited from the outpatient clinic of some of the orthopaedic surgeons working at Hull and East Yorkshire NHS trust hospitals over 18-24 months period. The patients coming to new clinic during this period will be explained about the trial and explained about the two methods of TKR- kinematically aligned and mechanically aligned. The participants involved in this study will NOT be paid any remuneration. The procedure involved and the follow up details will be explained to the patient and patient information leaflets handed over to them. The consent will be obtained in the clinic, in the presence of a nurse and / or family members of the patient. In case of non-English speaking patients, an interpreter will be called to do the translation of the communication between doctor and the patient. The interpreter in such scenarios will have to sign on the consent form in addition to the patients. Patients will be given sufficient time to arrive at a decision. In case they want to think over this study, they will be given one month, after which a telephonic conversation will be conducted to reach a decision. Patients can sign the consent form in the clinic or on the day of the surgery. On the day of surgery, reconfirmation of the consent to participate in the trial will be undertaken. Patient will be free to come out of trial at any stage of the trial if they wish to do so. Patients with special needs (mentally ill, children, those suffering from dementia) will be excluded from the study.
2. .Source of patients Patients visiting orthopaedic elective clinic of 2-3 consultants will be selected for this study. The study will be carried out at Hull Royal Infirmary and Castle Hill Hospitals. Expected number of patients eligible for the trial is 130 (65 in each group of kinematically aligned knee and mechanically aligned knee). We expect that at least 95% patients will agree to the trial. One surgeon will perform all kinematically aligned TKR and other surgeons will perform all mechanically aligned TKR which will ensure that there is no change of clinical practice for any surgeons in terms of kinematic or mechanical alignment of the TKR .

5….Randomisation Patients will be randomised using research randomiser computer software (randomisation.com).{16}.This program is a pseudo random number generator. The numbers are generated by complex algorithm (seeded by computer clock) that gives the appearance of randomness. This will help us randomly assign our study population into the two groups. It is a single blinded study and patients will be blinded. Envelopes will be opened after clinic appointment and patients will be booked for surgery based on which group they get randomised to.

6….withdrawal of subjects Patients may be withdrawn at any stage of the follow up/trial. If any patient develops dementia, deep infection, fracture, failure of extensor mechanism or any other injury which affects their mobility or ability to make decision will be withdrawn from the study. Under such circumstances randomization codes may have to be broken. Also if the patients want to sought second opinion or continue the treatment outside the trust, the codes may have to be broken. The codes will be available with the inpatient secretaries and may be obtained from them after taking due permission from the investigators. There won't be a need to replace a subject in this matter. Only randomization might have to be adjusted accordingly. The withdrawn subjects will be followed up in the clinics of respective surgeons, till a suitable period when they can be discharged to the care of the GPs, unless and until the subjects wishes not to do so.

7…Study treatments