This will be a prospective single cohort investigation of the Columbus all polyethylene tibia (Aesculap AG, Tuttlingen, Germany) used in total knee arthroplasty (TKA) surgery. The aim of the project is to determine post-operative outcome of the all polyethylene tibia up to two years.

Thirty consecutive TKA patients under the care of two orthopaedic consultants at the Golden Jubilee National Hospital who meet the inclusion/exclusion criteria will be recruited to the study and will be given the all polyethylene tibia. Participants will return for their standard postoperative followup appointments (6 weeks and 1 year post-operatively). In addition to standard care, a bone density scan using dual energy x-ray absorptiometery (DXA) will be done as part of the 6 weeks post-operative follow-up. A second DXA scan will be done at an additional appointment at the hospital between 18 and 24 months post-operatively for a bone density scan which is not part of standard care.

The data which will be analysed will be the results of the bone scan, computer generated data about the range of movement (RoM) and alignment of the operated knee collected as part of the operation, the RoM, clinical outcome and satisfaction data collected at the pre-operative assessment and post-operative followups, pre- and post-operative x-rays, complications, survivorship and surgeon experience of using the all polyethylene tibia. These data will be investigated to see if the all polyethylene tibia has satisfactory outcomes with no adverse effects.

Inclusion Criteria:

1. Unilateral TKA
2. Aged 70 year or older
3. BMI < 37.5
4. Suitable to receive the study implant

Exclusion Criteria:

1. Revision of existing knee replacement
2. Previous lower limb replacement
3. Proximal tibial bone defects
4. Diagnosed osteopenia or osteoporosis
5. Unable to give informed consent
6. Unwilling to take part
7. Unable to return to the Golden Jubilee National Hospital for followup appointments