| Part Ⅰ Epidemiology, clinical and radiological feature of acetabular fracture in the e1derlyObjective: To analyze the epidemiological features in patients aged 60 years and older, and to compare the clinical and radiological features in the elderly and younger patients with acetabular fractures. Methods: We retrospectively analyzed the clinical data of patients with acetabular fractures in the First Affiliated Hospital of Soochow University between January 1990 and December 2013. According to certain inclusion and exclusion criteria, a total of 637 patients(637 hips) with acetabular fractures were included in the study. The patients were divided into two group ? acetabular fractures in elderly(patients aged 60 years and older) and acetabular fractures in younger patients(patients aged less than 60 years), according to patients’ age. We evaluated the annual incidence of acetabular fractures in elderly and annual mean age; associated injuries in the elderly and younger patients with acetabular fractures; the mechanisms of injury in the elderly and younger patients; classification of fracture patterns in the elderly and younger patients; radiological features of fractures in the elderly and younger patients. Results: All of 637 patients, 133 patients were 60 years of age and older and the remaining 504 were less than 60 years of age. We identified a significant increase in the incidence of elderly patients with acetabular fractures between 1990 and 2013(6.7% in 1990 vs. 40.0% in 2013, p = 0.021), and a significant increase in the mean age of patients with acetabular fractures between 1990 and 2013(40.9±9.2 years in 1990 vs. 49.8±15.6 years in 2013, p = 0.045). The incidence of elderly patients with acetabular fractures increased by 1.7-fold between the early period(1990 to 2000) and the later(2001 to 2013) of this study(14.1% vs.24.1%, p=0.004). The incidence of associated injuries were significant lower in the elderly than in the younger patients(27.1% vs.48.8%, p=0.000). The most common mechanism of injury in the elderly was a fall(36.1%), but this accounted for only 0.2% of the younger patients with fractures(p=0.000). The incidence of anterior wall(8.3% vs.1.0%, p=0.000), anterior column(10.5% vs.4.8%, p=0.013), and anterior + posterior hemitransverse(3.8% vs.0.4%, p=0.005) were significant higher in the elderly than in the younger patients. The incidence of radiological features were significant higher in the elderly than in the younger patients, including quadrilateral plate fracture(23.3% vs.3.2%, p=0.000), Gull sign(21.1% vs.0.8%, p=0.000), anterior dislocation of hip(21.8% vs.10.3%, p=0.000), femoral head injury(13.5% vs.4.6%, p=0.000), comminuted posterior wall fracture(10.5% vs.3.6%, p=0.001) and posterior wall marginal impaction(12.0% vs.3.2%, p=0.000), except posterior dislocation of hip which was significant lower in the elderly than in the younger patients(16.5% vs.31.9%, p=0.000). Conclusions: There was an increasing trend of the proportion of elderly patients in acetabular fractures and the mean age of patients with fractures during the period of study. The older patients had a different incidence of associated injuries, mechanism of injury, fracture pattern, and radiological features compared with the younger patients. Considering the elderly is often associated with radiological features which have been reported in other studies to be predictive of a poor outcome, therefore medical decision-making for older patients with acetabular fractures, the surgeon must base on fracture pattern and radiological features, only in this way may patients achieve a satisfactory outcomes. In view of the fall is the most common cause of acetabular fracture in the elderly, therefore intervention strategies targeting the falls should be strengthened to prevent the occurrence of falls in elderly people.Part Ⅱ Predictors of clinical outcomes after surgical treatment of displaced acetabular fractures in the elderlyObjective: Outcomes following the open reduction and internal fixation(ORIF) of displaced acetabular fractures in the elderly have been inconsistent. Several factors associated with significant poor clinical outcomes have been reported; however, the factor that contributes independently to the outcomes remains unknown. This study aims to identify independent prognostic factors for the outcomes of surgically treated displaced acetabular fractures in the elderly. Methods: A total of 86 elderly patients with displaced acetabular fractures were treated by ORIF between May 1990 and June 2010. Matta’s criteria and modified Merle d’Aubigne-Postel score were used as reduction grades and clinical outcome measures, respectively. Reduction grades and six radiographic features were identified as prognostic factors. The six radiographic features include quadrilateral plate fracture, Gull sign, posterior dislocation of hip, femoral head injury(FHI), comminuted posterior wall fracture(CPWF) and posterior wall marginal impaction. Results: The average clinical score of the patients associated with the six radiographic features was 14.4±3.1, whereas the average clinical score for those without was 17.2±1.6 points. The average clinical score of the patients with anatomical, imperfect and poor reduction were 16.8±2.4, 14.5±2.3 and 11.3±1.4 points, respectively. Multivariate analysis identified three independent predictors of clinical outcomes: reduction grades(t =-10.45, p = 0.000), CPWF(t =-2.74, p = 0.008) and FHI(t =-3.51, p = 0.000). Conclusions: Both CPWF and FHI are important risk factors for clinical outcome. The postoperative quality of reduction independently predicted patient prognosis, and anatomical reduction is predictive of a good prognosis.Part Ⅲ Design and comparative biomechanical study of a novel fixation system for acetabular quadrilateral plate fractureObjective: Although a variety of implants are available for acetabular fracture involving the quadrilateral plate, the treatment remained challenging in this fracture combined with osteoporosis, comminuted or free floating medial wall fracture. This study aims to assess the biomechanical properties of a novel fixation system, and to compare it with other five different fixation techniques for quadrilateral plate fractures. Methods: Quadrilateral plate fractures were created in ten fourth-generation synthetic hemi-pelvises and were used to compare biomechanical properties by six fixation techniques:(1) Unidirectional hinged acetabular plate(UHAP, Experimental group),(2) L-shaped plate fixation(LPF, LPF group),(3) T-shaped plate fixation(TPF, TPF group),(4) H-shaped plate fixation(HPF, HPF group),(5) multidirectional titanium plate fixation(MTPF, MTPF group), and(6) pelvic brim long screws fixation(PBSF, PBSF group). The synthetic hemi-pelvis was fixed rigidly to a customized fixture which was placed on the testing table of the universal material testing machine(Instron Electro Puls E10000, Instron Corporation Norwood, MA, USA), and we used a customized metal femoral head connected to the load cells of the universal material testing machine. The position of synthetic hemi-pelvis which is the metal femoral head perpendicular to the acetabulum. The biomechanical properties were assessed using four factors: the load to create 2 mm displacement; the load to create 3 mm displacement, displacement under the maximum load level of 300 N, and stiffness. Results: In the experimental group, when specimens were loaded to 300 N, the mean displacement was 2.3±0.2 mm; when specimens were loaded to create 2 mm or 3 mm displacement, the mean was 220.2±49.0 N and 327.9±52.3 N, respectively; The mean stiffness was 119.9±21.1 N/mm. In the LPF group, when specimens were loaded to 300 N, the mean displacement was 3.0±0.5 mm; when specimens were loaded to create 2 mm or 3 mm displacement, the mean was 199.8±34.9 N and 310.0±46.0 N, respectively; The mean stiffness was 100.8±15.5 N/mm. In the TPF group, when specimens were loaded to 300 N, the mean displacement was 3.4±0.2 mm; when specimens were loaded to create 2 mm or 3 mm displacement, the mean was 138.4±20.7 N and 284.4±61.0 N, respectively; The mean stiffness was 78.5±12.6 N/mm. In the HPF group, when specimens were loaded to 300 N, the mean displacement was 3.2±0.7 mm; when specimens were loaded to create 2 mm or 3 mm displacement, the mean was 206.6±56.4 N and 306.3±48.1 N, respectively; The mean stiffness was 100.4±24.3 N/mm. In the MTPF group, when specimens were loaded to 300 N, the mean displacement was 1.7±0.3 mm; when specimens were loaded to create 2 mm or 3 mm displacement, the mean was 395.2±107.7 N and 645.7±77.8 N, respectively; The mean stiffness was 192.1±43.1 N/mm. In the PBSF group, when specimens were loaded to 300 N, the mean displacement was 1.7±0.3 mm; when specimens were loaded to create 2 mm or 3 mm displacement, the mean was 386.0±83.0 N and 539.2±68.6 N, respectively; The mean stiffness was 187.0±33.8 N/mm. The PBSF and MTPF group showed significantly higher load to create 2 mm, and 3 mm displacement compared with other groups(p < 0.05). Regarding the load to create 2 mm displacement, the lowest load was observed for the TPF group(p < 0.05). When specimens were loaded to 300 N, the PBSF and MTPF group showed the minimum displacement(p < 0.05), the UHAP group showed the second minimum displacement(p <0.05). Regarding stiffness, the MTPF and PBSF group attained highest values than all other groups(p < 0.05), UHAP group attained the second highest value(p < 0.05), the least value by the TPF group(p < 0.05). Conclusions: The multidirectional titanium plate and pelvic brim long screws provided the best biomechanical properties for quadrilateral plate fracture; unidirectional hinged acetabular plate gives a better biomechanical performance than L-shaped plate, T-shaped plate, and H-shaped plate. |
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