Project:
Custom positioning guides technique versus conventional technique in knee arthroplasty

Background:
The use of individualized positioning guides in total knee replacement (TKR) and Unicompartimental Knee Arthroplasty (UKA) created using MRI or CT scans is becoming more popular. Patient Matched Instruments (PMI), based on MRI or CT data, fit directly onto the patient's anatomy. With these positioning guides a knee arthroplasty is performed without the traditional invasive instrumentation. Preoperatively the anticipated positions can be defined in a three-dimensional computer program and surgery can be visualized digitally.

Methods:
Prospective randomized clinical studies
Radiostereometric Analysis (RSA)
Patient Matched Instruments (PMI)
X-ray (CT and Conventional)
Clinical follow up of patients

Purpose:
To investigate implant positioning and clinical results in TKR and UKA by using PMI.

Aim:
- To investigate whether pre-operative planning and use of custom made positioning guides (PMI) matches the postoperative position of the knee components in TKR and UKA
- To determine implant positioning, radiostereometry and clinical results with PMI compared to the conventional method in total knee arthroplasty

Planned studies:
1. Prospective randomized multicenter study: compare implant positioning and clinical results of the PMI method to the conventional method in TKR
2. Compare pre-operative software planning and use of PMI with the post-operative implant positioning in TKR
3. Compare pre-operative software planning and use of PMI to the post-operative implant positioning in UKA
4. Determine Vanguard implant stability with Radiostereometric Analysis (RSA)

Supervisors:
Stephan M. Röhrl, MD, PhD, Orthopaedic Surgeon
Bjarne Grøgaard, MD, PhD, Orthopaedic Surgeon
Finnur Snorrason, MD, PhD, Orthopaedic Surgeon

Current affiliation: Betanien Hospital, Skien, Norway. Orthopaedic surgery with special interest in knee, hip and shoulder arthroplasty.