Summary

We studied the influence of different surgeon’s and patient’s related factors on the postoperative tibial tray coronal alignment.

Abstract

Purpose

total knee arthroplasty (TKA) malalignment may result in pain and limited range of motion. The present study assessed the influence of different surgeon’s and patient’s related factors on the postoperative tibial tray coronal alignment.

Methods

the charts and the x-rays of a continuous prospective series of 1417 TKAs operated between 1987 and 2015 were retrospectively reviewed. The long-leg AP views were performed at 2 months postop and the tibial mechanical angle of the tibial tray was measured. Three groups were defined: varus (=87° n=167), valgus (=93° n=55) and well alignment (88° to 92° n=1195). The influence of several preoperative and perioperative factors was investigated: surgeon handedness and experience (junior or senior), previous tibial osteotomies, Ahlbäck stage of osteoarthritits, preoperative alignment, height and weight, age at surgery, approach (medial, lateral or tibial tubercle osteotomy), generation of implants, tray fixation, size of the tray and stem lenght. Univariate then multivariate analysis were performed to find out any correlation.

Results

multivariate analysis showed a strong correlation between varus alignment of the tibial tray and preoperative varus of the lower limb (p=0.037), increased BMI (p=0.016) and operated side opposite to the dominant surgeon’s arm (p=0.006). In a similar way a strong correlation was found between valgus alignment and preoperative valgus of the limb (p=0.026).

Conclusion

poor alignment of the tibial tray after TKA was associated with preoperative malalignment of the lower limb, increased BMI and an index knee which was opposite to surgeon’s dominant arm.