To examine whether removing the infrapatellar fat pad from the knee during total knee arthroplasty affects the patient outcome in terms of pain and knee function following the procedure. Currently there is no consensus on whether removing this tissue from the knee has a positive or detrimental effect. Small studies have been published, some showing improved symptoms and some worse symptoms. Current practice of orthopaedic surgeons is either to routinely remove or routinely retain the tissue when performing total knee arthroplasty.

Aim and Objectives The aim of the study is to examine whether removing or retaining the infrapatellar fat pad influences pain or knee function in the short and medium term.

Study Design A single centre randomized controlled trial of total knee arthroplasty with and without infrapatellar fat pad excision

Methodology A research nurse or the responsible consultant orthopaedic surgeon will identify potentially eligible patients from the list of those invited to attend the pre-operative assessment clinic for total knee arthroplasty. As part of their written invitation to attend this clinic, they will receive an information leaflet about the study from their consultant.

A research nurse or the responsible consultant orthopaedic surgeon will discuss the trial with them at the pre-assessment clinic. If the patient is willing to take part in the study they would then be asked to sign a consent form and will be reminded of the opportunity to withdraw from the study at any point. Their consent will be confirmed on the day of their admission for surgery.

Consented patients will be randomized to one of two arms of the study, the only variable being whether or not the infrapatellar fat pad is excised.

Randomisation to excision or retention of the infrapatellar fat pad will occur immediately prior to the total knee arthroplasty procedure being performed, and will be performed using the program freely available at http://www.randomization.com. Sealed envelopes will be prepared and the operating surgeon will open the randomisation envelope immediately before performing the total knee arthroplasty procedure. The procedure will then be performed and recorded. The excision of the infrapatellar fat pad itself takes less than 20 seconds to perform, and the knee replacement procedure is otherwise performed as normal. The outcome of the randomisation and procedure performed will be known only to the operating surgeon and researcher and not to those following up the patients and recording the outcome measures.

Seven consultant orthopaedic surgeons will take part in the trial. All perform total knee arthroplasty surgery regularly . Other than the consent process and additional questionnaires and clinical assessment performed, the care of patients in the study will be identical to all other non-study patients. Follow up will follow our normal routine pathway of visits at 3 months, 1 year and 2 years.

Inclusion Criteria:

• Male/female patients between 40 and 100 years of age
• Undergoing primary total knee arthroplasty

Exclusion Criteria:

• Patient undergoing unicompartmental knee arthroplasty
• Patient undergoing revision knee arthroplasty
• Patient undergoing arthroplasty using non standard implants
• Previous patella surgery or injury
• Cognitive impairment
• Lack of conversational English

double blinded RCT