Abstract
BACKGROUND
The aim of Patient-specific instrumentation surgery is to improve accuracy and limit the range of surgical variability. The main purpose of this study is to summarize and compare the radiographic outcomes of TKA performed using Patient-specific instrumentation compared with conventional techniques.
PURPOSES
In this study, we compared varus/valgus of the individual prosthesis components, rotation of femoral components and posterior slope of tibial components of 40 TKAs performed using a patient-specific technique with values from a matched control group of patients who were operated on by conventional intramedullary alignment technique.
METHODS
We retrospectively evaluated 55 primary TKAs performed for osteoarthritis: conventional instrumentation using the PFC Sigma (n = 15) patient-specific instrumentation using GMK MyKnee© (n = 40). Varus/valgus of the individual prosthesis components, rotation of femoral components and posterior slope of tibial components were measured from CT images taken post operation, whether there were more outliers with one of the two methods. The fraction of outliers (> 3°) was determined.
RESULTS
There was excellent reliability with low standard deviations for the determination of femoral component rotation and varus/valgus of the tibial components. There were significantly more outliers in the conventional (26.7%) group than in the patient-specific instrument group (10.0%).
Outliers in Varus/valgus of femoral components were comparable between groups (7.5% in the patient-specific instrument group and 6.7% in the conventional instrument group).
Other parameters such as posterior slope of tibial components did not differ in terms of outliers.
CONCLUSIONS
In this study, Patient-specific instrument was effective in significantly reducing outliers of rotational femoral component and varus/valgus of the tibial components alignment during TKA.
Therefore, additional studies are needed to determine whether patient-specific instrumentation improves clinical function or patient satisfaction.
