OBJECTIVE: Compared to the posterior approach (PA), the direct anterior approach (DAA) can achieve better clinical outcomes for total hip arthroplasty (THA). The purpose of this study was to investigate whether the same advantages associated with the DAA could be attained in patients undergoing simultaneous bilateral THA.
METHODS: We retrospectively reviewed 89 patients who underwent one-stage bilateral THA through the DAA (group A, n = 46) and through the PA (group B, n = 43) between June 2015 and November 2017 at our institution. The patients were followed up for a minimum of 1 year. There were no significant differences in gender, age, body mass index (BMI), preoperative hemoglobin level, preoperative Harris hip score (HHS), and preoperative visual analogue scale (VAS) score between the two groups (P > 0.05 for all).
RESULTS: The incision length, operation time, intraoperative blood loss, blood transfusion volume, and the length of stay (LOS) were significantly less in group A than in group B (p < 0.05). The surgery-related complications were not significantly lower in group A (5.43%) than in group B (10.47%) (χ2 = 2.209, p = 0.112). In 46 cases in group A, one hip had an acetabular anteversion higher than normal value. In both groups, one hip developed aseptic loosening. The HHS was significantly higher in group A than in group B 1, 3, 12 month(s) after operation (p < 0.05). The VAS was significantly lower in group A than in group B 1, 3, 12 month(s) after operation. Against the simple Likert scale, comprehensive satisfaction was significantly higher in group A (97.8%, 45/46) than in group B (76.7%, 33/43) (χ2 = 9.119, p = 0.003).
CONCLUSIONS: In patients who underwent simultaneous bilateral THA, DAA could significantly relieve pain, accelerate the functional recovery of hip joint and improve the satisfaction more than PA. In clinical practice, however, more attention should be paid to strict compliance to operative indications and the prevention of early complications. The long-term effectiveness warrants further observation.

BACKGROUND: This study aimed to compare the clinical data of ankylosing spondylitis (AS) patients who underwent unilateral and bilateral total hip arthroplasty (THA) due to advanced hip involvement. Furthermore, to determine the factors associated with bilateral THA.
METHODS: Utilizing a single-institution database, we selected 373 consecutive AS patients undergoing primary THA from 2012 to 2017 and compared the clinical characteristics and anti-tumor necrosis factor (TNF) therapy of the patients who underwent unilateral and bilateral THA. Logistic regression was used to identify factors associated with bilateral THA.
RESULTS: Bilateral THA was performed in 67.3% (n=251) of the patients. Male patients had a higher frequency of undergoing bilateral THA compared with female ones (P<0.05). The proportion of the patients who had bilateral onset in hips, administration of TNF inhibitors, flexion contracture in the hip, and a BASRI-hip score of 4 was significantly higher in patients with bilateral THA than that with unilateral THA (P<0.05). Patients with bilateral THA experienced longer disease duration than those with unilateral THA (P<0.05). The results of the logistic regression showed that factors related to bilateral THA were bilateral onset in hips, administration of TNF inhibitors, a BASRI-hip score of 4, and an erythrocyte sedimentation rate (ESR) level (P<0.05).
CONCLUSIONS: Bilateral THA is more common in AS patients with advanced hip involvement. Bilateral onset in hips, a BASRI-hip score of 4, and a higher level of ESR are risk factors associated with bilateral THA, while anti-TNF therapy is a protective factor reducing the progression of hip involvement to bilateral THA.

BACKGROUND: Bilateral osseous ankylosed hips secondary to ankylosis spondylitis (AS) are relatively rare but impact the quality of life hugely. Cementless total hip arthroplasty (THA) for bilateral osseous ankylosed hips with AS is a challenging procedure. No previous literature compares the clinical outcomes of synchronous and sequential bilateral THA for these special patients.
METHODS: 23 patients (46 hips) were retrospectively analyzed and divided into bilateral THA synchronously (group A) and sequentially (group B). The clinical measurement, radiological assessments, and complications were compared. Independent sample T test was used for data analysis.
RESULTS: Harris Hip Scores (HHS) improved greatly for both groups (P = 0.58) as well as the range of motion (P = 0.64). But group B can realize shorter time (3.6 ± 1.2 days) to walk for the first time postoperatively (P = 0.02). Group A needed more blood transfusions (P = 0.028). For group A, no statistical difference was found in the bilateral inclination of cup (IC) (P = 0.48) and femoral offset (FO) (P = 0.07). For group B, no statistical difference was observed in bilateral IC (P = 0.37) but in bilateral FO (P = 0.04). Group A showed the fewer difference of bilateral IC (P = 0.02), while comparative measurements were found for two groups in the difference of bilateral FO (P = 0.78) and leg length discrepancy (P = 0.83). For both groups, the total hospital expense for each patient was similar and almost all patients were very satisfied with the outcomes. For group A, one patient encountered femoral fracture intraoperatively and another patient encountered hip dislocation and delay union of wound. 3 hips from group A and 3 hips from group B encountered heterotopic ossification.
CONCLUSIONS: Our retrospective research demonstrated that cementless bilateral THA was a reliable treatment for osseous ankylosed hip due to AS. Synchronous and sequential bilateral THA can realize similarly satisfactory clinical outcomes and radiographic evaluation.