Objective To compare the short-term effectiveness of staged bilateral total hip arthroplasty via different approaches. Methods Thirty-two patients (64 hips) with bilateral hip disease were treated with total hip arthroplasty between January 2012 and December 2014. There were 20 males and 12 females with the mean age of 45.3 years (range, 30-67 years). There were avascular necrosis of femoral head in 14 cases, developmental dislocation of the hip in 12 cases, ankylosing spondylitis in 4 cases, osteoarthritis in 2 cases. All patients were treated with total hip arthroplasty; and the direct anterior approach (DAA) or direct lateral approach (DLA) was chosen for the unilateral hip randomly. The length of incision, operation time, total blood loss volume, the time of first postoperative activity, and the acetabular anteversion angle were compared. The Harris score, visual analogue scale (VAS) score, and incidence of complication were compared between 2 groups. Results All incisions healed at stage Ⅰ. All patients were followed up 20-53 months (mean, 39.6 months). The length of incision, total blood loss volume, the time of first postoperative activity were significantly shorter in DAA group than in DLA group (P<0.05). The operation time was significantly longer in DAA group than in DLA group (P<0.05). There was no significant difference in acetabular anteversion angle between 2 groups (t=1.122, P=0.266). The incidence of complication were 25.00% and 15.63% in DAA group and DLA group, respectively, showing no significant difference (χ2=0.869, P=0.536). The Harris score in DAA group significantly increased at 3 and 9 months after operation than in DLA group (P<0.05); there was no significant difference at 18 months after operation between 2 groups (P>0.05). The VAS score was significantly lower in DAA group than in DLA group at 1 day, 3 days, and 1 week after operation (P<0.05); there was no significant difference at 4 and 8 weeks between 2 groups (P>0.05). The prosthesis did not loosen and sink during the follow-up. Conclusion Total hip arthroplasty via DAA can reduce operation related complication and speed up the recovery of hip function at the early stage after operation. However, the lateral cutaneous nerve injury is the most common complication.
This study aims to analyze the biomechanical stability of Magic screw in the treatment of acetabular posterior column fractures by finite element analysis. A three-dimensional finite element model of the pelvis was established based on the computed tomography (CT) and magnetic resonance imaging (MRI) data of a volunteer and its effectiveness was verified. Then, the posterior column fracture model of the acetabulum was generated. The biomechanical stability of the four internal fixation models was compared. The 500 N force was applied to the upper surface of the sacrum to simulate human gravity. The maximum implant stresses of retrograde screw fixation, single-plate fixation, double-plate fixation and Magic screw fixation model in standing and sitting position were as follows: 114.10, 113.40 MPa; 58.93, 55.72 MPa; 58.76, 47.47 MPa; and 24.36, 27.50 MPa, respectively. The maximum stresses at the fracture end were as follows: 72.71, 70.51 MPa; 48.18, 22.80 MPa; 52.38, 27.14 MPa; and 34.05, 30.78 MPa, respectively. The fracture end displacement of the retrograde tension screw fixation model was the largest in both states, and the Magic screw had the smallest displacement variation in the standing state, but it was significantly higher than the two plate fixations in the sitting state. Magic screw can satisfy the biomechanical stability of posterior column fracture. Compared with traditional fixations, Magic screw has the advantages of more uniform stress distribution and less stress, and should be recommended.
Objective To explore the effectiveness of distal humeral dual-planar osteotomy followed with distal humeral lateral column anotomical locking plate fixation in the treatment of adult cubitus varus deformity combined with flexion restriction. Methods The clinical data of 6 adult patients with cubitus varus deformity and flexion restriction treated with dual-planar osteotomy and internal fixation between April 2012 and September 2014 were reviewed. There were 3 males and 3 females with an average age of 22.2 years (range, 18-35 years). All the patients had history of elbow injury in childhood, the age being injured was 6.5 years on average (range, 2-13 years). There was no nerve injury, elbow strength weak, or unstable complications before admission. The preoperative elbow flexion was (107.50±5.24)°, elbow extension was (–12.17±3.48)°; the carring angle was (–19.50±4.46)°, the contralateral elbow carrying angle was (11.50±2.67)°; the length of humerus was (0.42±0.38) cm shorter than the unaffected humerus. The postoperative carrying angles, elbow flexion and extension, and humerus length were recorded. The modified Laupattarakasem criteria in which the comparison of bilateral elbow range of motion excluded was used to evaluate the results. Results Primary healing of incision was got in all patients and there was no early postoperative complications. All the patients were followed up 19-27 months (mean, 20.8 months). During the follow-up, there was no complication such as loosening and breakage of the internal fixators and all fractures were healed within 3 months after operation. At last follow-up, the elbow flexion was (124.17±5.85)°, the elbow extension was (0.83±2.04)°, the carrying angle was (12.00±4.19)°, and the humerus shortening was (1.88±0.45) cm, all showing significant difference when compared with preoperative ones (t=–6.742, P=0.001; t=–11.068, P=0.000; t=–20.400, P=0.000; t=–13.914, P=0.000). According to the modified Laupattarakasem criteria, 1 case was excellent, 4 were good, and 1 was fair with an excellent and good rate of 83.3%. Conclusion Normal carrying angle can be restored and elbow flexion can be increased by coronal closing wedge and sagittal trapezoid dual-planar osteotomy, single lateral anatomical locking plate fixation is available for early mobilization.