The effect of weight-bearing positions on coronal lower limb alignment: A systematic review

Background: The coronal alignment of the lower limb is generally accepted as a major determinant of surgical outcome in total knee arthroplasty (TKA). To achieve the ideal post-operative alignment, surgeons need to be aware of the influence that weight -bearing positions have on the final knee alignment. Therefore, this review aims to define the effect of varying weight-bearing positions on the coronal alignment of the lower limb. We hypothesized that a coronal alignment defor-mity increases with loading. Methods: The PubMed, Medline and google scholar databases were searched systemati-cally in June 2022. Only studies which compared coronal alignment with a standardized radiographic protocol in the single leg, double leg and supine positions were included. To obtain pooled estimates of the effect of different weight-bearing positions, random -effect analysis were fitted using SAS. Results: Compared to the supine position, double leg weight-bearing positions were found to be associated with a more pronounced varus deformity (mean difference in HKA is 1,76 & DEG; (95% CI 1,32: 2,21), p < 0.0001)). The mean difference in HKA between double leg and single leg weight-bearing conditions was 1.43 & DEG; (95% CI (-0,042;2,90), p = 0.0528). Conclusion: The overall knee alignment was found to be influenced by the weight-bearing position. An average difference of 1.76 & DEG; in HKA-angle was found between a double leg -stance and supine position, tending to increased varus in the former weight-bearing posi-tion. It is therefore possible that the deformity could increase by 1.76 & DEG; if knee surgeons only follow a pre-op planning based on double-leg stance full length radiographs. & COPY; 2023 Elsevier B.V. All rights reserved.