Abstract
Background
In our pursuit of surgical accuracy and precision we often neglect to evaluate our results objectively. With the use of Computerised Tomography (CT) in pre-operative planning we can use the same technology in order to evaluate surgical accuracy.
Hypothesis
The use of Patient Specific Instrumentation (CT based) produces an accurate intra operative guide for precision cutting in knee arthroplasty.
Method
A prospective study using Patient Specific Instrumentation (customized cutting blocks) was performed on 35 patients. The small cohort value is due to the high costs of post-operative CT. A CT based software was used to evaluate the pre-operative knee alignment. Surgery was planned and verified on a web based programme with the use of 3D models. Cutting blocks were custom made and used as intra operative guide to make the relevant cuts.
Pre and post-operative CT scans were compared for AP and lateral alignment, femoral external rotation and flexion and tibial slope. Knee Society scores were also used to evaluate the clinical outcome.
Results
The values for AP and lateral limb alignment, femoral external rotation and flexion were the same as the pre-operative values with no significant deviation (maximum 2 degree difference). The posterior tibial slope was the only value that showed significant deviation from the pre-planned values.
Conclusion
There was a significant difference for the posterior tibial slope but otherwise we found no difference in pre and post-operative limb alignment measurements. Pre-operative planning with the use of CT based customised cutting blocks is a reliable and accurate option to obtain optimal alignment and prosthetic orientation in total knee arthroplasty.
NO DISCLOSURES
