Combined pelvic ring disruption and acetabular fracture: associated injury patterns in 40 patients.

OBJECTIVES: Combined pelvic ring disruptions and acetabular fractures are thought to be uncommon. Our objectives were to characterize concomitant injury patterns and to compare them with historically observed rates for each injury in isolation. DESIGN: Retrospective review comparing a study group with historical controls. Fracture patterns were compared with our institution's isolated injury patterns and with isolated injury patterns of other published series. SETTING: Level I academic medical center. PATIENTS: Between 1997 and 2001, 854 pelvic ring disruptions and 457 acetabular fractures were evaluated. Forty patients sustained combined injuries. INTERVENTION: None. MAIN OUTCOME MEASUREMENTS: Fracture patterns, Injury Severity Scores, and mortality rates. RESULTS: Our series of combined injuries included 5% posterior wall fractures. This was significantly different from the 30% incidence of posterior wall fractures among isolated acetabular fractures at our institution (P < 0.006). No posterior column or posterior column with associated posterior wall fractures occurred. Fifty-three percent of the patients sustained anterior-posterior compression pelvic ring injuries, exceeding our center's 19% norm for isolated pelvic ring injuries (P < 0.001). For combined injuries, the mean injury severity score was 27.9 and the overall mortality rate was 13%. Early death occurred in 19% of patients with combined anterior-posterior compression injuries and 6% with lateral compression injuries. CONCLUSIONS: Patients with combined pelvic and acetabular injuries have multiple system injuries and high Injury Severity Scores. Fracture patterns differ from those observed with isolated injuries. Posterior acetabular fractures are uncommon components. Anterior-posterior compression pelvic injuries seem much more frequent in cases of combined injuries than isolated injuries and are associated with high mortality rates. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Acetabular fracture types vary with different acetabular version.

PURPOSE: Acetabular fractures typically occur in high energy trauma. Understanding of the various contributing biomechanical factors and trauma mechanisms is still limited. While several investigations figured out what role femoral position during impact plays in distinct fracture patterns, no data exists on the influence of acetabular version on the fracture type. Our study was carried out to clarify this issue. METHODS: Radiological data sets of 192 patients (145 male, 47 female, age 14-90 years) sustaining acetabular fractures were assessed retrospectively. The crossover ratio of the crossover sign and presence or absence of the posterior wall sign and ischial spine sign were used to determine acetabular retroversion on conventional radiographs. Acetabular version in the axial plane was measured on a computed tomography (CT) scan. Statistics were then performed to analyse the relationship between the acetabular fracture type according to the Letournel classification and acetabular version. RESULTS: A significant difference (p = 0.029) in acetabular version was found between fractures of the anterior [mean equatorial edge (EE) angle 19.93°] and posterior (mean EE angle 17.53°) acetabulum in the CT scan. No difference was shown on the measurements on conventional radiographs. CONCLUSIONS: Acetabular version in the axial plane has an influence on the acetabular fracture pattern. While more anteverted acetabula were frequently associated with anterior fracture types according to the Letournel classification, retroversion of the acetabulum was associated with posterior fracture types.

Normal values of Wiberg's lateral center-edge angle and Lequesne's acetabular index--a coxometric update.

BACKGROUND: The historical pathological cut-off values for Wiberg's lateral center-edge (LCE) angle and Lequesne's acetabular index (AI) are below 20° and above 12° for the LCE and AI, respectively. The aim of this study was to reassess these two angles more than 50 years after their introduction using a standardized conventional radiological measurement method, considering changing social habits and their associated physiological changes. METHODS: A total of 1,226 anteroposterior radiographs of the pelvis (2,452 hips) were obtained according to a strict standardized radiographic technique allowing reliable measurements of the LCE angle and the AI. RESULTS: Distributions of the LCE and AI were pronouncedly Gaussian, with mean values of 33.6° for the LCE and 4.4° for the AI. The 2.5th and 97.5th empirical percentiles were 18.1 and 48.0° for the LCE and -6.9 and 14.9° for the AI. These intervals contained 95 % of the data in our large sample. Small but statistically significant differences between the sexes and right and left hips have been demonstrated. Correlation between age and coxometric indices was low. CONCLUSION: The above findings do not conflict with the historical benchmarks. Statistical differences between sexes and between right and left hips were not clinically relevant. No conclusion can be drawn about coxometric indices and clinical manifestations of hip dysplasia.

A biomechanical comparison of a locking plate, a nail, and a 95° angled blade plate for fixation of subtrochanteric femoral fractures.

OBJECTIVE: To compare the biomechanical performance of a cephalomedullary nail (CMN), a proximal femoral locking plate, and a 95° angled blade plate in a comminuted subtrochanteric fracture model. METHODS: A comminuted subtrochanteric femoral fracture model was created with a 2-cm gap below the lesser trochanter in 15 pairs of human cadaveric femora confirmed to be nonosteoporotic. The femora were randomized to treatment with one of the previously mentioned 3 devices. Each was tested under incrementally increasing cyclic load up to 90,000 cycles from 50% to 250% of body weight to simulate progressive weight bearing during 3 months of an average 700-N (approximately, 70 kg or 150 lb) person. Force, number of cycles, and total load sustained to reach 10 mm of displacement were compared. Failure modes were also noted. RESULTS: The CMN construct withstood significantly more cycles, failed at a significantly higher force, and withstood a significantly greater load than either of the plate constructs (P < 0.001). Varus collapse was significantly lower in the CMN construct (P < 0.0001). Modes of failure differed among implant-bone constructs with damage to the femoral head through implant cutout in 5 of 10 blade plate specimens and 2 of 10 CMN specimens, whereas no damage to the femoral head bone was observed in any of the locking plate constructs. CONCLUSIONS: The CMN construct was biomechanically superior to either the locking plate or 95° blade plate constructs. The locking plate construct was biomechanically equivalent to the blade plate construct.

Relationship between Wiberg's lateral center edge angle, Lequesne's acetabular index, and medial acetabular bone stock.

OBJECTIVE: Knowledge of acetabular anatomy is crucial for cup positioning in total hip replacement. Medial wall thickness of the acetabulum is known to correlate with the degree of developmental dysplasia of the hip (DDH). No data exist about the relationship of routinely used radiographic parameters such as Wiberg's lateral center edge angle (LCE-angle) or Lequesne's acetabular index (AI) with thickness of the medial acetabular wall in the general population. The aim of our study was to clarify the relationship between LCE, AI, and thickness of the medial acetabular wall. MATERIALS AND METHODS: Measurements on plain radiographs (LCE and AI) and axial CT scans (quadrilateral plate acetabular distance QPAD) of 1,201 individuals (2,402 hips) were obtained using a PACS imaging program and statistical analyses were performed. RESULTS: The mean thickness of the medial acetabulum bone stock (QPAD) was 1.08 mm (95% CI: 1.05-1.10) with a range of 0.1 to 8.8 mm. For pathological values of either the LCE (<20°) or the AI (>12°) the medial acetabular wall showed to be thicker than in radiological normal hips. The overall correlation between coxometric indices and medial acetabular was weak for LCE (r =-0.21. 95% CI [-0.25, -0.17]) and moderate for AI (r = 0.37, [0.33, 0.41]). CONCLUSIONS: We did not find a linear relationship between Wiberg's lateral center edge angle, Lequesne's acetabular index and medial acetabular bone stock in radiological normal hips but medial acetabular wall thickness increases with dysplastic indices.

Radiographic markers of acetabular retroversion: correlation of the cross-over sign, ischial spine sign and posterior wall sign.

Radiological diagnosis of acetabular retroversion is based on the presence of the cross-over sign (COS), the posterior wall sign (PWS), and prominence of the ischial spine (PRISS). The primary purpose of the study was to correlate the quantitative cross-over sign with the presence or absence of the PRISS and PWS signs. The hypothesis was that both, PRISS and PWS are associated with a higher cross-over sign ratio or higher amount of acetabular retroversion. A previous study identified 1417 patients with a positive acetabular cross-over sign. Among these, three radiological parameters were assessed: (1) the amount of acetabular retroversion, quantified as a cross-over sign ratio; (2) the presence of the PRISS sign; (3) the presence of the PWS sign. The relation of these three parameters was analysed using Fisher's exact test, ANOVA, and linear regression analysis. In hips with cross-over sign, the PRISS was present in 61.7%. A direct association between PRISS and the cross-over sign ratio (p < 0.001) was seen. The PWS was positive in 31% of the hips and was also significantly related with the cross-over sign ratio (p < 0.001). In hips with a PRISS, 39.7% had a PWS sign, which was a significant relation (p < 0.001). In patients with positive PWS, 78.8% of the cases also had a PRISS (p < 0.001). Both the PRISS and PWS signs were significantly associated with higher grade cross-over values. Both the PRISS and PWS signs as well as the coexistence of COS, PRISS, and PWS are significantly associated with higher grade of acetabular retroversion. In conjunction with the COS, the PRISS and PWS signs indicate severe acetabular retroversion. Presence and recognition of distinct radiological signs around the hip joint might raise the awareness of possible femoroacetabular impingement (FAI).

Evaluation of computed tomography for determining the diagnosis of acetabular fractures.

OBJECTIVE: We assessed whether, in contrast to reports in the literature, computed tomographic (CT) scans improve the ability to classify acetabular fractures in comparison with plain radiographs. DESIGN: Prospective. SETTING: Level I trauma center. PATIENTS: Seventy-five patients with 75 acetabular fractures treated between June 2005 and May 2006. INTERVENTION: Four different image sets for each patient were evaluated: image set A, Judet view plain radiographs plus axial view CT scans; image set B, Judet view plain radiographs alone; image set C, three-dimensional CT reconstructions; and image set D, CT-simulated anteroposterior and Judet views of the pelvis. The 300 image sets were viewed in random order by four orthopaedic trauma fellowship-trained surgeons who independently recorded a diagnosis. A gold standard diagnosis was determined by group consensus. MAIN OUTCOME MEASUREMENTS: Agreement among four imaging methods was evaluated by using kappa statistics for multiple raters and nominal data. RESULTS: Comparing the gold standard diagnosis with the four image sets, Judet view plain radiographs had a worse kappa value than CT scans (P < 0.05). The adjusted kappa values for all three image sets that included CT scans averaged greater than 0.62, showing substantial agreement, whereas the image set with plain radiographs alone (image set B) had a lower kappa value of only 0.48 (P < 0.05). CONCLUSIONS: In contrast to previous reports in the literature, the accuracy of plain radiographs alone was less than the accuracy of CT scans in terms of diagnosis. The interobserver reliability was also worse for plain radiographs alone.

Resuscitation before stabilization of femoral fractures limits acute respiratory distress syndrome in patients with multiple traumatic injuries despite low use of damage control orthopedics.

BACKGROUND: Femoral shaft fractures are associated with acute respiratory distress syndrome (ARDS). The idea that primary intramedullary nailing increases the incidence of ARDS has theoretical support. Our approach to treating femoral fractures in patients with multiple traumatic injuries is to perform reamed nailing after adequate resuscitation has been shown by normalizing lactate plus optimized ventilatory and hemodynamic parameters. Damage control orthopedics (DCO) with primary external fixation usually is reserved for those rare patients who do not respond to resuscitation. Our hypothesis was that this approach yields a low rate of ARDS. METHODS: A prospective trauma database was searched for all femoral shaft fractures treated at a Level I trauma center during a 3-year period, yielding 582 patients. Exclusion criteria included death before treatment (n = 9), age younger than 16 years (n = 16), age older than 65 years (n = 35), fractures that were not amenable to nail fixation (n = 31), shaft fractures treated with a plate (n = 3), patients with bilateral femoral shaft fractures who had a primary nail placed in one femur and an external fixator on the other limb (n = 1), and patients with an Injury Severity Score (ISS) 17, only 12% were initially treated with DCO, and 88% were treated with primary reamed nailing. The 227 patients achieved successful early resuscitation as shown by lactate values that decreased significantly on the operative day compared with presenting values (p < 0.05). ARDS rates were low, including rates for the subgroup of patients with lung injury (thoracic Abbreviated Injury Scale score >2, n = 175) who were treated with nailing and had an ARDS rate of 2.0% and a death rate of 2.0%. The ARDS rate for the most severely injured patients who underwent nailing (ISS >28, thoracic Abbreviated Injury Scale score >2, n = 78) was only 3.3%, and 1.7% died. CONCLUSIONS: In the context of resuscitation before reamed intramedullary nailing of femoral shaft fractures, our rate of ARDS was lower (p < 0.001) than that of a similar study reported in the literature in which the DCO approach was used in up to 36% of patients (p < 0.001) and was more in keeping with previously reported rates of ARDS. This remained true despite frequent use of early reamed femoral nailing and infrequent use of DCO. An explanation for the discrepancy between the centers might be differences in preoperative resuscitation or medical care provided to treat shock.

Prevalence of acetabular dome retroversion in a mixed race adult trauma patient population.

The goals of the present investigation were to identify the prevalence of acetabular dome retroversion in a mixed race population, to quantify the average amount of cross-over ratio, and to determine normative values. The presence of the cross-over sign and its overlap ratio was assessed for 2,925 hips meeting strict radiographic criteria of the pelvic radiograph. Fifty-two percent of the hips had no cross-over sign whereas 48% had at least a minimal amount of overlap of the anterior and posterior acetabular wall. Analysis of only those hips with positive cross-over sign revealed a mean cross-over ratio of 26% +/- 11% (range: 3 to 93). Forty-two percent of the patients had no cross-over on either side, 18% on one side, and 40% on both sides. The presence of the cross-over sign is more common than previously expected. Further studies will be necessary to determine the risk of pathological abnormality and to correlate symptoms to crossover ratios. Surgery should not be based solely on the finding of a cross-over sign without clinical correlation.

Reconstruction of distal tibia fractures using a posterolateral approach and a blade plate.

OBJECTIVE: The aim of this article is to report a technique for the management of distal tibia fractures with significant anteromedial soft-tissue injury. The patients were initially treated with a spanning external fixator, open reduction and internal fixation (ORIF) of the fibula at the discretion of the surgeon, and soft-tissue management or flap coverage. ORIF of the tibia was performed on a staged basis, using a 90-degree cannulated blade plate and autogenous iliac crest bone graft through a posterolateral approach. DESIGN: Retrospective analysis of a consecutive series of patients. SETTING: Two academic level-1 trauma centers. PATIENTS: Fifteen patients with 15 distal tibia fractures (13 open fractures), Orthopedic Trauma Association (OTA) type 43A3 and 43C1, were definitively treated and followed to union between July 2000 and July 2004. Five patients were referred from outside sources after initial stabilization. INTERVENTION: Initial stabilization in an external fixator and management of the open fracture and soft tissue. Staged ORIF of the tibia with bone graft was performed through a posterolateral approach when the soft tissues allowed. OUTCOME MEASUREMENTS: Radiographic union, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, and complications. RESULTS: All 15 fractures were followed to union. Average time to union was 20 (12 to 47) weeks from the time of fixation with blade plate and bone grafting. (AOFAS) ankle-hindfoot score was used to measure outcome. The average score was 81 (60 to 97) out of a possible 100. There were no deep infections. There was one nonunion; the fracture united after revision with a locked plate and bone graft. The average length of follow-up was 14 months (4 to 37). CONCLUSIONS: The staged treatment of high-energy distal tibia fractures with soft-tissue injury can lead to good outcomes and consistent bone union. Our results were obtained by the combination of the posterolateral approach, careful soft-tissue management, and stable internal fixation.