ABSTRACT
Objective To investigate the relationship between pelvic asymmetry and Crowe classification of unilateral developmental dysplasia of the hip in adults. Methods According to the inclusion criteria, 100 cases of unilateral DDH in adults were collected, including 78 females and 22 males, with an average age of 56.3 years old (range, 21-79 years). In terms of Crowe classification, there were 30 cases of Crowe typeⅠ, 24 cases of Crowe typeⅡ, 23 cases of Crowe typeⅢ, and 23 cases of CroweⅣ. The normal?side and affected?side pelvic vertical height (the distance from the highest point of the ischial tuberosity to the iliac crest peak) were measured via the radiogram of anteroposterior pelvis. Furthermore, we compared the affected?side pelvic vertical height with the normal?side and analyzed the relationship between Crowe classification and the difference in pelvic verti?cal height. Results The average pelvic vertical height was 23.38±1.46 cm in the normal?side and 22.41±1.38 cm in the affected?side. The average D?value of pelvic vertical height between two sides is 0.98 ± 0.76 cm. From Crowe typeⅠto Ⅳ, the average heights of the normal?side were 22.89±1.09 cm, 23.23±2.07 cm, 23.75±1.16 cm, 23.79±1.22 cm, while those of the affected?side were 22.70 ± 0.98 cm, 22.41 ± 1.98 cm, 22.47 ± 1.12 cm and 21.92 ± 1.32 cm. The average D?values in each group were 0.19 ± 0.37 cm, 0.82±0.43 cm, 1.28±0.32 cm, 1.87±0.59 cm. The differences between the normal?side and the affected?side in each type were statistically significant. The average D?value increased significantly with Crowe type increased, and there was a positive correla?tion between the D?value of bilateral pelvic vertical height and the degree of hip dislocation. Conclusion The pelvic asymmetry does exist in adult patients with unilateral developmental dysplasia of the hip. Moreover, the asymmetry has positive correlation with the degree of hip dislocation.
ABSTRACT
Objective To investigate the mechanical stability and clinical outcome of minimally invasive plate osteosynthesis of pubic ramus fractures.Methods Stability of minimally invasive plate osteosynthesis and traditional open fixation of pubic ramus fractures was compared in finite element analysis.A retrospective analysis was performed on fractures of pubic rami (126 sides) in 101 consecutive patients treated with minimally invasive plate osteosynthesis from 2005 to 2012.Operation time,intraoperative blood loss and follow-up of fracture healing were evaluated.Results In finite element analysis,traditional open fixation and minimally invasive plate osteosynthesis resulted in the maximum pelvic force of 7.35 MPa and 5.59 MPa,maximum fracture displacement of 4.31 mm and 4.38 mm and relative fracture gap displacement of 0.029 mm and 0.012 mm.Displacement of fracture gap after minimally invasive plate osteosynthesis and traditional open fixation was reduced 26％ and 59％ respectively.In the clinical study,the surgery acquired for pubic ramus fractures averaged 65 minutes with mean blood loss of 94 ml.Follow-up duration was 5-50 months (mean,24.3 months).Reduction of the fracture as assessed using Matta' s criteria was excellent in 118 sides (93.7％),good in eight sides (6.3％).Totally,the fracture was healed within postoperative 12 weeks in 117 sides and within postoperative 6 months in 9 sides.No iatrogenic nerve or vascular injury occurred.Conclusions Minimally invasive plate osteosynthesis is a safe and effective technique for fixation of pubic ramus fractures.Moreover,satisfactory results can be achieved together with less trauma and better cosmetic effect.