Effect of medial tibial torsion on the sagittal alignment of lower legs in patients with medial knee osteoarthritis

Changes in the femoral varus and rotational profiles are correlated in women with varus osteoarthritic lower limbs

INTRODUCTION

Previous studies have reported the relationship between coronal alignment of the lower limbs and the rotational profile of the femur and tibia. However, the relationship between coronal alignment of the femur and tibia and their rotational profiles in patients with varus osteoarthritic knees is unclear.

METHODS

One hundred women with varus osteoarthritic knees (varus OA group) and 50 women with neutrally aligned lower limbs without osteoarthritis (non-OA group) were evaluated retrospectively. The coronal alignment and rotational profile of the femur and tibia were evaluated, and the correlation between coronal alignment and rotational profile was analyzed, respectively.

RESULTS

The femoral anteversion, posterior condylar angle of the distal femur, and tibial torsion were significantly smaller in the varus OA group than in the non-OA group. In the varus OA group, the femoral anteversion and rotational profile of the distal femur had significantly negative correlations with the degree of femoral varus, while tibial torsion was not related to the degree of tibial varus. In the non-OA group, there was no relationship between coronal alignment and rotational profiles of the femur and tibia in both the varus OA and non-OA groups.

CONCLUSION

Femoral anteversion and the rotational profile of the distal femur were negatively correlated with the degree of femoral varus in Asian women with varus osteoarthritic knees. This study enhanced the understanding of the relationship between changes in coronal alignment of the femur and tibia and their rotational profiles in patients with varus osteoarthritic lower limbs, although this study was limited by the small sample sizes and methodological quality.

Internal tibial torsion is related to syndesmosis injury in a large osteological collection

BACKGROUND

The long-term consequences of tibial torsion remain unclear. This study evaluated whether syndesmotic injuries are associated with tibial torsion.

METHODS

A collection of over 3000 cadaveric skeletons was screened for irregular bony prominence along the lateral distal tibia, consistent with previous syndesmosis injury. Tibial torsion was measured and compared to 1034 control cadaveric tibiae.

RESULTS

Mean torsion of 236 specimens with syndesmotic injury was 6.2±8.9 degrees, while that of control specimens was 7.9±8.8 degrees (P = 0.008). Multiple regression analysis showed a non-statistically significant trend toward internal torsion and syndesmotic injury (standardized beta=-0.051, P=0.059). Syndesmosis injury was present in 48/200 specimens (24.0%) with internal torsion and 31/199 specimens (15.6%) with external torsion (P=0.035).

CONCLUSION

This association between internal tibial torsion and syndesmotic injury suggests that internal tibial torsion might not be an entirely benign condition and merits further study.

Analysis of the effect of tibial torsion on tibial osteotomy in knee arthroplasty using a three-dimensional computed tomography-based modelling technique

Background

Extramedullary systems are commonly used in knee arthroplasty, with the rod location being determined from the tibial torsion line during surgery. The traditional method for tibial torsion measurement is not in accordance with clinical practice. This study aimed to evaluate proximal and distal tibial torsion using 3-dimensional (3D) computed technology to establish a new evaluation method, as well as to investigate the association between tibial torsion and postoperative alignment deviation.

Methods

Fifty-five osteoarthritis tibias with >10°varus preoperatively were divided into valgus, neutral, and varus groups based on their postoperative alignment deviation. A new method based on clinical practice was built using a 3D tibial model. Proximal and distal tibial torsions were measured by both the new and traditional methods. In addition, tibial osteotomy that followed the intramedullary osteotomy system was simulated on the 3D model in the varus and valgus groups to investigate the association between tibial torsion and alignment deviation.

Results

Proximal tibial torsion was smaller and distal torsion was greater in the valgus group than the other two groups, according to the new method (p = 0.03 and p = 0.02, respectively). No significant difference was found when comparing these torsions by the traditional method (p = 0.782 and p = 0.753, respectively). In the valgus group, the postoperative alignment deviation improved after simulated osteotomy guided by the intramedullary system, while no significant improvement was found in the varus group.

Conclusion

According to this new tibial-rotation evaluation method, valgus deviation in knee arthroplasty was identified as the main cause for knees in which the proximal tibial internal torsion is too small and the distal external torsion is too great. The use of an intramedullary system may help reduce this deviation.

Trial registration

Prospectively registered.

Kinematic analysis of knee varus and rotation movements at the initial stance phase with severe osteoarthritis of the knee

BACKGROUND

The purposes of this study were to understand the kinematics changes in the frontal and horizontal planes with severe medial knee OA at the stance phase and to examine the relationship between varus and rotational movements.

METHODS

The OA group comprised 18 knees in 12 subjects (five men, seven women) with a Kellgren-Lawrence grade of three or four in at least one knee. From the results of gait analysis, we calculated Spearman rank-correlation coefficients for the following items: varus angle at initial contact (IC); varus angle at loading response (LR); amount of varus thrust from IC to LR; rotational angle at IC; rotational angle at LR and amount of rotational angle change from IC to LR.

RESULTS

The results indicated that, as the external rotation angle at IC and internal rotational movement from IC to LR increased, the maximum varus angle to LR showed a tendency to become large. In addition, varus thrust showed a tendency to become larger as the external rotation angles increased at IC and LR. The subjects with severe knee OA showed a strong correlation between the knee varus angle at IC and at LR. Furthermore, an increase in movement to internal rotation of the knee during the initial stance phase increased the knee varus angle at LR.

CONCLUSIONS

The control of the rotational movement according to the extent of varus thrust during the initial stance phase may have possible effects to decrease the load on the medial compartment of the knee.