Incorrect positioning of the implant and improper alignment of the limb following total knee arthroplasty (TKA) can lead to rapid implant wear, loosening, and suboptimal function. The aim of this study was to determine if the alignment of the tibial component is associated with an early failure of the implant.

A retrospective cohort study with two groups of patients undergoing TKA between 2006 and 2011. Group A (GA) early aseptic loosening (15±);Group B (GB) randomized case-control (35). Early failure arthroplasties were considered when there was clinical and radiological loosening signs before 48 months.

In GA, 93.3% female, mean age 64.93±8.0 years, mean BMI 29.2±4.6kg m², 86.7% varus knees, average alignment of the tibial component of 6.2±2.5. In GB, 85.7% female, mean age 70.9±5.7 years, mean BMI 28.2±2.6kg m² 88.57% varus knee. In both comorbidities (P=0.885) and BMI (P=0.334) did not correlate with early failure of the implant. Interestingly we found a significant correlation (P<0.0035) between younger patients and aseptic loosening. We found another significant correlation (P<0.0001) between increasing angle in the coronal plane of the tibial component and aseptic loosening.

There are several factors associated with early failure in TKA. In addition to septic causes variables such as BMI, age and malalignment of prosthetic components are described in literature. In our study, younger patients had a statistically significant association with early loosening. BMI showed no relationship with early loosening, different to previously published results. The alignment deviation in the coronal plane of the tibial component in TKA is a determining factor for early loosening, whereas values“greater than 6” may be considered unacceptable in view of longevity arthroplasty.