Objective
To compare the effectiveness of one-stage bilateral total hip arthroplasty by direct anterior approach (DAA) and by posterolateral approach, and to investigate the application value of DAA in one-stage bilateral total hip arthroplasty.
Methods
The clinical data of 65 patients who underwent one-stage bilateral total hip arthroplasty by DAA or posterolateral approach between June 2010 and November 2015 were analyzed retrospectively. DAA was used in 34 cases (group A) and posterolateral approach was used in 31 cases (group B). There was no significant difference in the gender, age, body mass index, preoperative hemoglobin level, etiology, disease duration, preoperative Harris score, and preoperative visual analogue scale (VAS) score between 2 groups (P>0.05) with comparability. The incision length, operation time, intraoperative blood loss, total blood transfusion volume, hospitalization time, early postoperative complications, Harris score, and VAS score were recorded and compared between 2 groups. The simple Likert scale method was applied to evaluate the patient satisfaction, and the imaging evaluation was used.
Results
The incision length, operation time, intraoperative blood loss, total blood transfusion volume, and hospitalization time of group A were significantly less than those of group B (P<0.05). The patients were followed up 15-48 months (mean, 25.3 months) in group A and 12-51 months (mean, 27.6 months) in group B. The overall incidence of complications related to surgery in group A (10.29%) was significantly lower than that of group B (19.35%) (χ2=8.769, P=0.023). The acetabular anteversion and abduction angle were in the normal range of 2 groups except 1 hip (1.47%) of group A had a higher acetabular anteversion than normal value. Unstable fixed prosthesis happened in 1 hip of groups A and B respectively, and the remaining femoral calcar had no obvious bone resorption and fixed stably. The Harris score and VAS score at each time point after operation of 2 groups were significantly improved when compared with preoperative scores (P<0.05), and the differences between the time points after operation were also significant (P<0.05). The Harris score at 1 and 3 months after operation and the VAS score at 3 days after operation of group A were significantly better than those of group B (P<0.05), but no significant difference was found at last follow-up between 2 groups (P>0.05). According to the simple Likert scale method to analyze patient satisfaction, comprehensive satisfaction of group A (97.1%, 33/34) was significantly higher than that of group B (67.7%, 21/31) (χ2=10.343, P=0.001).
Conclusion
The application of DAA in one-stage bilateral total hip arthroplasty can significantly relieve the pain, accelerate the recovery of hip joint function, and improve the patient satisfaction. But in clinical application, more attentions should be paid to strictly grasp the indications and prevent the early complications. The long-term effectiveness needs to be further observed.
A certain degree of varus alignment is physiological in the native knee, and alignment strategies such as kinematic and functional alignment permit residual postoperative varus. However, identical total varus angles may result from varying combinations of femoral and tibial varus, whose biomechanical implications for implant loading and ligament stress remain unclear. This study aims to investigate the biomechanical effects of different femoral–tibial varus configurations in total knee arthroplasty (TKA). Using combined geometric modeling and finite element analysis, TKA models with different varus combinations were constructed to evaluate changes in limb moment arms, polyethylene insert stress, and ligament forces during static knee flexion (0°–90°). Results demonstrated that a higher proportion of femoral varus, under equivalent total varus and flexion angles, led to reduced maximum polyethylene stress and decreased tension in the medial collateral ligament (MCL) and anterolateral ligament complex (ALL). Knee flexion angle had a more significant impact on polyethylene stress than varus: stress increased by approximately 2.48 times at 90° flexion compared to 0°, whereas 12° varus increased stress by only approximately 14%. The ALL experienced the greatest tensile load during flexion, indicating a key stabilizing role. In conclusion, optimizing the combination of femoral and tibial varus may help redistribute loads and improve implant longevity. This study reveals, from a biomechanical perspective, how different varus configurations affect stress distribution in the prosthesis and surrounding soft tissues, suggesting that intraoperative osteotomy strategies should comprehensively consider the combined alignment of the femur and tibia.
