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Treatment of both-column fractures with posterior wall involvement is still a controversial topic. This type of posterior wall fracture is different from isolated acetabular posterior wall fracture (AO/OTA62-A1). The aim of this study is to compare the morphology of the posterior wall fragments of these two fracture patterns using computed tomography (CT) scans. All measured data were compared, and the differences between the groups (acetabular both-column fractures with posterior wall involvement were included in group A, and acetabular isolated posterior wall fractures were included in group B) were significant (P ≤ 0.05), including the direction angle, displacement, articular surface-posterior cortex ratio and articular surface area of the fracture fragment. The intraclass correlation coefficient of the measurements included inter-observer (ICC = 0.860) and intra-observer (ICC = 0.853). The morphology of the posterior wall fragments associated with both-column fractures is significantly different from that in isolated acetabular posterior wall fractures, and the treatment of the posterior wall fragment involved in both-column fractures of the acetabulum should be different from that of isolated acetabular posterior wall fractures. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Introduction Besides head-insert articulation in hip joint replacements, micro-motions between the backside of assembled polyethylene acetabular liners and the metal cup may cause additional wear. Pelvic osteolysis frequently occurs in the region of screw holes, and cup loosening hints to clinically relevant amounts of polyethylene backside wear. It has yet to be confirmed whether backside wear particles differ in size and morphology compared to articulating wear. Previous methods have been limited to subjective assessment of backside surface damages without consideration of wear debris. The aim of this study was to develop and validate a method for quantitative in vitro measurements of polyethylene backside wear in artificial hip cups and to characterize these wear particles for the first time. Methods Titanium cup-systems (Plasmafit®Plus7, Aesculap, UHMWPE liner) were sinusoidally loaded (2.5 kN) and a torque of 5 Nm was simultaneously applied. The front and rear side of the cup were separated to isolate backside wear. After 2 × 106 cycles the surrounding fluid was filtered and a particle analysis was performed. Results Backside wear had a particles size of 64.1 ± 1.9 nm and was verified as round and oval particles with partly rough outlines. An estimated total number of particles of 1.26 × 109 ± 1.67 × 108 per 106 cycles was determined. Conclusion Backside wear was estimated to be several times lower than published values of articulating wear. However, polyethylene backside wear particles represented significantly smaller particles with partly roughened outlines than articulating wear particles and may therefore cause higher biological response in macrophage-mediated bone resorption compared to articulated particles. Statement of Significance Within this study, an analytical method for quantitative measuring polyethylene backside wear of artificial hip cups was successfully developed and validated for the first time. It could be shown that backside wear is still present, even in modern cup-systems. These findings can be further used for investigations of the osteolytic potential of polyethylene particles, for evaluating and improving new implant systems and to evaluate the effectiveness of screw hole plugs to prevent the particle migration to the acetabulum. [ABSTRACT FROM AUTHOR]

Background: Pubic bone nonunion and delayed union are reported as post-operative complications after peri-acetabular osteotomy (PAO). However, few studies have determined the incidence of delayed union using computed tomography (CT) scans. This study aimed to determine the incidence of delayed union at one year after PAO using X-ray and CT scans.Methods: We performed a retrospective review of 150 hips in 132 consecutive patients with acetabular dysplasia who underwent PAO between January 2012 and June 2016 and evaluated 107 hips for which pelvic CT scans taken at one year after PAO were available. Clinical evaluations included age at surgery, weight, body mass index (BMI) and history. Radiographic evaluations were to assess pubic, ischial and iliac delayed union at one year post-operatively.Results: Based on X-ray analysis, the incidence of delayed union in the pubic, ischial and iliac bones was 11.2% (12 hips), 5.6% (6 hips) and 0% (0 hips), respectively, and20.6% (22 hips), 8.4% (9 hips) and 0% (0 hips), respectively, based on CT scans.Conclusion: The incidence of delayed union of the pubis and ischium at one year after PAO according to CT scans was higher than that based on X-ray imaging. CT scans are useful in patients with some symptoms at the osteotomy site.Level Of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Background: Elderly patients have more special medical needs when compared with young ones; thus, the results of open reduction and internal fixation (ORIF) for acetabular fractures should be stratified by age in these patients. This study seeks to determine whether the age of the patient influences the results of the ORIF for acetabular fractures.Methods: We performed a retrospective analysis of prospectively collected data on 53 elderly patients with displaced acetabular fractures who underwent ORIF between May 2004 and May 2011. Patients were divided into two groups by age: young-old group (60-74 years) and old-old group (75-90 years). The number of patients in each group was 28 and 25. The reduction quality and clinical function was evaluated using the Matta criteria and modified Postel Merle D'Aubigne Score, respectively. Operative time, bleeding amount, and complications were recorded.Results: Patients in old-old group had significantly lower anatomical reduction rate (p = 0.024), less operative time (p = 0.021), and less bleeding amount (p = 0.016) than those in the young-old group. The reduction quality in the young-old group was strongly associated with clinical function (p < 0.05). However, no difference in clinical function was detected among the different reduction qualities in the old-old group (p > 0.05). Moreover, no significant difference in clinical functions (p = 0.787) and complications (p = 0.728) was detected between the two groups.Conclusions: Old-old patients may expect comparable clinical functions and complications with young-old patients. The reduction quality in old-old patients may be not significantly associated with clinical function. Different treatment strategies may be applied for acetabular fractures with ORIF in different age groups. [ABSTRACT FROM AUTHOR]

Background: Pelvic discontinuity is uncommon and presents the surgeon with complex reconstructive challenges. The objective of this study is to report the results of current strategies used in the treatment of pelvic discontinuity.Methods: We retrospectively analyzed prospectively collected data on 113 consecutive revision total hip arthroplasties performed for the treatment of unilateral pelvic discontinuity at a single institution. The study included 18 male and 95 female patients with a mean age of 63 years at the time of revision surgery. Preoperative, immediate postoperative, and latest follow-up radiographs were reviewed to assess healing of the discontinuity as well as acetabular component stability. Treatment modalities included an uncemented cup with a posterior column plate (50 hips; 44%), a cup-cage construct (27 hips; 24%), an antiprotrusio cage with or without a posterior column plate (26 hips; 23%), and an uncemented cup alone (10 hips; 9%). The average duration of follow-up for each of these types of surgical reconstruction was similar (range, 3.9 to 7.2 years).Results: Five-year revision-free survivorship of the implant was best with a cup-cage construct (100%) and worst with an uncemented cup with a posterior column plate (80%) and a cup alone (80%). Healing of the discontinuity was achieved in 50% of the hips with an uncemented cup alone, 74% of the hips with an uncemented cup and a posterior column plate, 74% of the hips with a cup-cage construct, and 88% of the hips with an antiprotrusio cage construct (91% of these hips when structural allograft was used). The overall complication rate was 26.5%. The average Harris hip score improved from 54 preoperatively to 69 postoperatively (95% confidence interval: 50 to 57 preoperatively and 65 to 72 postoperatively; p = 0.017).Conclusions: Improved survivorship and healing rates were seen in this series when a reconstruction cage was used as an adjunct to an uncemented cup (cup-cage) or in combination with structural allograft bone that bridged the discontinuity.Level Of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Misplaced screw during the internal fixation of acetabular fractures may penetrate the hip joint which might cause chondrolysis and traumatic osteoarthritis in the future. This study aims to acquire the safe path for screw insertion along inferior border of the arcuate line fixation route at acetabular area.Methods: Computed tomography (CT) scans of 98 patients without pelvic trauma were rebuilt for three-dimensional models of pelvis. After depicting the fixation route curve, five cross-sections perpendicularly to the curve were established from the anterior of pelvis to the posterior along inferior border of the arcuate line. The safe screw lengths for section 1 and 5 were measured from the computer models. In section 2, 3 and 4, a line from the screw entry point tangent to the inferior edge of the acetabulum was depicted and the measurements of minimum safe direction of screw insertion were performed then marked with angle θ.Results: The safe screw lengths for section 1 and 5 were 22.29 ± 4.41 mm and 32.64 ± 4.70 mm (n = 98). The minimum safe angles of screw insertion for the middle three sections 2, 3, and 4 were 65.38 ± 10.23°, 74.20 ± 10.20°, and 57.88 ± 11.11°(n = 98), respectively. The results for the male group (n = 98) indicated smaller minimum safe angles in these three sections compared with the female (n = 98).Conclusions: Compared to male, the minimum safe angles of screw placement at acetabular area for female should be more away from inferior edge of acetabulum and tilt to the bottom of pelvis along inferior border fixation route in surgical management of acetabular fractures. [ABSTRACT FROM AUTHOR]

Background: Sarcopenia is a condition of clinically relevant loss of muscle mass and function. Acetabular fractures in elderly patients are common and difficult to treat. This study aimed to determine if sarcopenia is common in elderly patients with acetabular fractures and correlates with lower-energy mechanisms of injury, higher rates of complications, and higher mortality than patients with normal muscle mass.Methods: The Rhode Island Hospital Trauma Database was queried for patients who were ≥60 years of age from 2005 to 2014 using the International Classification of Diseases, Ninth Revision, code for closed acetabular fracture, 808.0. Charts were retrospectively reviewed for demographic data, operative intervention, mechanism of injury, mortality, comorbidities, and other factors. Computed tomography (CT) was used to determine the muscle cross-sectional area and to calculate the skeletal muscle index.Results: The database revealed 192 patients coded for acetabular fracture; of these, 181 were correctly diagnosed. Ninety-nine patients had recorded body mass index (BMI) and adequate CT scans to measure the skeletal muscle index. Forty-two patients (42.4%) had sarcopenia, and 57 patients (57.6%) did not have sarcopenia. There were no significant differences in demographic characteristics between the groups with the exception of BMI and sex. BMI was higher in patients who did not have sarcopenia (31.7 kg/m) than it was in patients with sarcopenia (23.6 kg/m) (p < 0.001). Male sex was significantly greater (p = 0.0104) in patients with sarcopenia at 76.2% (32 of 42 patients) than in patients without sarcopenia at 50.9% (29 of 57 patients). Fractures in patients without sarcopenia were associated with a higher-energy mechanism of injury in 78.9% of cases compared with 52.4% of cases of patients with sarcopenia (p = 0.005). Sarcopenia was significantly associated (p = 0.0419) with increased 1-year mortality (28.6%) compared with the absence of sarcopenia (12.3%). This association was even stronger if in-hospital mortality was excluded (p = 0.00074). Finally, anterior column fractures were more likely (p = 0.017) to be sustained by patients with sarcopenia at 47.6% (20 patients) than by patients who did not have sarcopenia at 24.6% (14 patients).Conclusions: Sarcopenia is common in elderly patients with acetabular fractures and is associated with lower-energy mechanisms, anterior column fractures, and higher risk of 1-year mortality.Level Of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Introduction: Anatomical reduction of displaced acetabular fracture is not without its' limitations and complications. This study is conducted to assess clinical and radiological outcomes as well as complications of treating displaced acetabular fractures with emphasis on anatomical reduction in weight-bearing area, mainly the posterior column, and imperfect reduction of the anterior column is acceptable. However, stability of both columns is mandatory.Methods: It was a retrospective study carried out in a Level 1 arthroplasty and trauma centre. 23 patients (17 males, 6 females) with average age of 50.1 years (range, 36-68 years) with displaced acetabular fracture treated with combined incisions and plate-cable systems were included. There were 3 elementary and 18 associated fractures according to Letournel classification. Average follow-up was 23.5 months (range, 12-38.7 months). Mean operation time was 160min (range: 75-320min). Functional scores were evaluated using Harris Hip Score (HHS) whilst reduction was assessed by Matta criteria. Any displacement of reduction, osteoarthritis, heterotopic ossification, and other complications was recorded.Result: 65.2% (15/23) of the patients obtained excellent HHS and 21.7% (5/23) had good HHS. There were 12 anatomical, 6 imperfect, and 5 poor reductions. No displacement was recorded in final follow-up. Complications documented: three lateral femoral cutaneous nerve injuries, two conversions to total hip arthroplasty, three Brooker stage 1 heterotrophic ossification, one pulmonary embolism and one screw irritation. No incidence of wound breakdown, infection and radiological osteoarthritis was reported.Conclusions: Imperfect reduction of the anterior column provided clinical outcomes that are as good as total anatomical reduction. This approach minimizes soft tissue damage and reduces perioperative morbidities. [ABSTRACT FROM AUTHOR]

Background: Acetabular dysplasia (AD) is a well-known cause of osteoarthritis (OA) of the hip, with its prevalence previously determined on plain radiography. The prevalence of preexisting AD was reported as 7.3% in a patient-based Asian population. Although computed tomography (CT) could evaluate AD in multiple planes, its prevalence using multiplanar CT images has not been reported. We investigated its prevalence with CT on coronal, axial, and sagittal planes and then determined if adding the axial and sagittal planes enhanced the investigation.Methods: We retrospectively examined 52 consecutive Japanese individuals (mean age 59.4 years) who had undergone CT for conditions unrelated to hip disorders. The inclusion criteria of CT images were (1) reconstructed axial slice thickness of ≤1 mm and (2) normal pelvic rotations and tilt. Exclusion criteria were (1) age <20 years, (2) neither hip center could be clearly detected, (3) evidence of hip OA. The parameters used to define AD on the coronal plane were the center-edge angle, Sharp angle, acetabular index, acetabular depth ratio, and acetabulum head index. The anterior and posterior acetabular sector angles were used as axial parameters and the vertical-center-anterior margin angle as the sagittal parameter. AD prevalence was calculated using multiplanar images and then compared with the previously reported Asian prevalence using 95% confidence intervals (CI). In this study, we defined "prevalence" as the proportion of subjects who had AD in at least one hip.Results: The mean prevalence of AD on coronal, axial, and sagittal planes was 16.9, 15.4, and 7.7%, respectively. The lowest prevalence found by combining the three planes was 25.0% (95% CI 15.2-38.2%). This prevalence was significantly higher than that in the previously reported Asian population (7.3%).Conclusions: At the lowest estimate, the prevalence of AD evaluated in three planes was more than twice as high as the previously reported prevalence in Asians when we investigated its prevalence using multiplanar images. The prevalence of AD in the axial and sagittal planes was not negligible. We therefore suggest that it is important to add axial and sagittal planes' data when investigating the prevalence of AD. [ABSTRACT FROM AUTHOR]

Objective: Treatment of acetabular fractures remains one of the most challenging tasks that orthopaedic surgeons face. An accurate assessment of the injuries and preoperative planning are essential for an excellent reduction. The purpose of this study was to evaluate the feasibility, accuracy and effectiveness of performing 3D printing technology and computer-assisted virtual surgical procedures for preoperative planning in acetabular fractures. We hypothesised that more accurate preoperative planning using 3D printing models will reduce the operation time and significantly improve the outcome of acetabular fracture repair.Methods: Ten patients with acetabular fractures were recruited prospectively and examined by CT scanning. A 3-D model of each acetabular fracture was reconstructed with MIMICS14.0 software from the DICOM file of the CT data. Bone fragments were moved and rotated to simulate fracture reduction and restore the pelvic integrity with virtual fixation. The computer-assisted 3D image of the reduced acetabula was printed for surgery simulation and plate pre-bending. The postoperative CT scan was performed to compare the consistency of the preoperative planning with the surgical implants by 3D-superimposition in MIMICS14.0, and evaluated by Matta's method.Results: Computer-based pre-operations were precisely mimicked and consistent with the actual operations in all cases. The pre-bent fixation plates had an anatomical shape specifically fit to the individual pelvis without further bending or adjustment at the time of surgery and fracture reductions were significantly improved. Seven out of 10 patients had a displacement of fracture reduction of less than 1mm; 3 cases had a displacement of fracture reduction between 1 and 2mm.Conclusions: The 3D printing technology combined with virtual surgery for acetabular fractures is feasible, accurate, and effective leading to improved patient-specific preoperative planning and outcome of real surgery. The results provide useful technical tips in planning pelvic surgeries. [ABSTRACT FROM AUTHOR]

The gold standard for fractures of the acetabulum is to perform an open reduction and internal fixation in order to achieve anatomical reduction. In a well-defined subset of patients, percutaneous techniques may be employed but achieving reduction by closed means can be challenging especially for fractures with large degrees of displacement. Such patient may include elderly patients who may not have the physiologic reserve to withstand open approaches. In our paper, we present a new option using laparoscopic assisted reduction of the acetabular fracture and percutaneous fixation. The young obese patient refused all forms of blood products transfusion and presented with a displaced transverse posterior wall fracture. While we do not recommend routine use of such technique and recognize its numerous limitations, we present it as an alternative strategy in a small subset of patients. [ABSTRACT FROM AUTHOR]

Purpose: The aims of this retrospective study were to firstly introduce three practical bulk bone graft techniques based on acetabular morphology for dysplasia and secondly evaluate the long-term durability of acetabular reconstruction using those techniques combined with cemented total hip arthroplasty (THA).Methods: The study comprised 101 consecutive THAs with a minimum follow-up of ten years; these procedures were categorised as being L shape (n = 58), Wall (n = 33) and D shape (n = 10) types.Results: At the last follow-up, all bone grafts acquired trabecular reorientation, and no evidence of revision for aseptic or radiological loosening was noted.Conclusions: These bone graft techniques will be effective for improving the management of dysplasia in cemented THA by providing both acetabular reconstruction and cement containment. [ABSTRACT FROM AUTHOR]

The adult human pelvis is useful to estimate age because it contains three age indicators-the pubic symphysis, auricular surface, and acetabulum. This study tested the accuracy, inaccuracy, and bias of age estimation from the Suchey-Brooks pubic symphysis, Osborne auricular surface, Rissech and Calce acetabulum aging methods, and a summary age of these indicators. The study sample consisted of 212 White individuals with known age and sex from the William M. Bass Donated Skeletal Collection. The Rissech method performed the best, was the most accurate method with smallest inaccuracy and bias, followed by the Osborne, Suchey-Brooks, summary age, and then Calce methods. Though the Pearson correlation showed only the Suchey-Brooks method to correlate significantly with known age, it is likely the Suchey-Brooks study sample coincidentally reflected the age distribution of this test sample. Results suggested that Bayesian prediction may improve age estimation and should be applied to other age indicators. [ABSTRACT FROM AUTHOR]

Background: Better understanding of three-dimensional (3D) morphology of the pelvis at the area of inferior border of the arcuate line is very important, which could guide the surgeons to treat pelvic and acetabular fractures more efficiently. The objective of this study is to provide references for screw placement and design of anatomical internal fixators for the fixation route along the pelvic inferior border of the arcuate line.Methods: Seventy five cases of computed tomography (CT) scan data were collected using Medical Image Database in Shanghai General Hospital between December 2009 and November 2010. 44 males and 31 females, aging from 21 to 91 years (average: 57.8 years) were enrolled. Using MIMICS 13.0, these data were used for three dimensional (3D) reconstructions of pelvic model. A curve from the pubic tubercle, along the inferior border of the arcuate line, to the sacroiliac joint was depicted and then divided into 11 equal parts. The measurements of whole length of the curve, the radius of the curvature and the thickness of bone at each decile point were performed, respectively.Results: The thinnest bone thickness at acetabular area was 17.24 ± 2.90 mm and 9.94 ± 2.69 mm for male and female, respectively. The radius of curvature at the decile points 1, 8 and 10 were smaller compared with the surrounding points.Conclusions: Using a screw shorter than 10 mm perpendicular to the bone surface along the inferior border of the arcuate line can avoid intra-articular screw penetration. There should be more recontouring of the plate at the areas of pubic tubercle and posterior edge of the acetabulum when placing a fixator along this fixation route. This study provides solid guidance for pelvic and acetabular surgeries as well as designing of anatomical fixators along inferior border fixation route at this area. [ABSTRACT FROM AUTHOR]

Introduction: Pelvic fractures requiring surgical fixation are rare injuries but present a great societal impact in terms of disability, as well as economic resources. In the literature, there is no description of these costs. Main aim of this study is to describe the direct and indirect costs of these fractures. Secondary aims were to test if the type of fracture (pelvic ring injury or acetabular fracture) influences these costs (hospitalization, consultation, medication, physiotherapy sessions, job absenteeism).Materials and Methods: We performed a retrospective study on patients with surgically treated acetabular fractures or pelvic ring injuries. Medical records were reviewed in terms of demographic data, follow-up, diagnosis (according to Letournel and Tile classifications for acetabular and pelvic fractures, respectively) and type of surgical treatment. Patients were interviewed about hospitalization length, consultations after discharge, medications, physiotherapy sessions and absenteeism.Results: The study comprised 203 patients, with a mean age of 49.1 ± 15.6 years, who had undergone surgery for an acetabular fracture or pelvic ring injury. The median treatment costs were 29.425 Euros per patient. Sixty percent of the total costs were attributed to health-related work absence. Median costs (in Euros) were 2.767 for hospitalization from trauma to definitive surgery, 4.530 for surgery, 3.018 for hospitalization in the surgical unit, 1.693 for hospitalization in the rehabilitation unit, 1.920 for physiotherapy after discharge and 402 for consultations after discharge. Total costs for treating pelvic ring injuries were higher than for acetabular fractures, mainly due to the significant higher costs of pelvic injuries regarding hospitalization from trauma to definitive surgery (p < 0.001) and hospitalization in the surgical unit (p = 0.008).Conclusions: Pelvic fractures are associated with both high direct costs and substantial productivity loss. [ABSTRACT FROM AUTHOR]

Background: Transverse acetabular ligament (TAL) has been used as a landmark for aligning cup anteversion. The use of TAL as a guide is based on the assumption that TAL version is distributed within the safe zone of acetabular cup. However, there was rarely reported to compare anteversion between TAL and acetabulum using direct measurement methods. The purpose of this study was to measure the anteversion of TAL in computed tomography arthrography (CTA) and compare it with Lewinnek's safe zone and anteversion of bony acetabulum. Methods: 81 patients (90 hips) were selected among 204 patients (228 hips) who received CTA for hip pathology evaluation between March 2010 and June 2013. The anteversion of TAL measured at the lowest level of the acetabular notch and the anteversion of the acetabulum was measured at the level of femoral head center. Results: The mean TAL anteversion was 11.8° (SD 4.5, range 0-22.2). In eight hips (8.8%), TAL anteversion was outside the safe zone (15° ± 10°) as defined by Lewinnek. The mean acetabular anteversion was 13.3° ± 4.4° (range -1.0° to 22.6°). There was a strong correlation between TAL anteversion and acetabular anteversion (Pearson's correlation coefficient; 0.908, p < 0.001). Conclusions: TAL anteversion has a large individual variation, and considerable portion of hips have TAL anteversion outside the safety zone of cup anteversion. TAL anteversion is influenced by acetabular anteversion. In hips with retroverted or pauci-anteverted acetabulum, TAL should be used cautiously because there is a risk of cup malposition. [ABSTRACT FROM AUTHOR]

Background: Although little is known, a limited number of three-dimensional computed tomography (CT) images of the pelvis present focal concavity of posterior superior acetabulum. The purpose of the present study was to investigate this morphologic deformity and its relation with dysplasia and retroversion in adults who were expected to have the original morphology of the acetabulum after growth.Methods: Consecutive adult patients with hip pain who visited our hospital and had three-dimensional pelvic CT images were retrospectively analyzed after approval of the institutional review board; exclusion criterions included diseases, injuries and operations that affect the morphology of the hip including radiographic osteoarthritis Tönnis grades 2 and 3. Focal concavity of posterior superior acetabulum was evaluated by three-dimensional CT image. Acetabular dysplasia was determined by lateral center edge (LCE) angle <25°, Tönnis angle >10°, and anterior center edge (ACE) angle <25° on standing hip radiographs. Acetabular version angle was measured at the one-fourth cranial level of axial CT image. A subgroup analysis included only younger adult patients up to 50 years.Results: The subjects analyzed were 46 men (92 hips) and 54 women (108 hips) with a median age of 57.5 (21-79) and 51.0 (26-77) years, respectively. Focal concavity of posterior superior acetabulum was observed in 13 hips; 7 patients had unilaterally, while 3 patients showed bilaterally. Among these hips, pain was observed in 8 hips but 4 hips (2 patients) were associated with injuries. This morphologic abnormality was not associated with acetabular dysplasia determined by LCE angle <25°, Tönnis angle >10° or ACE angle <25°. Of note, no acetabulum with the deformity plus dysplasia was retroverted. These findings were confirmed in a subgroup analysis including 22 men (44 hips) and 27 women (54 hips) with a median age of 31.0 (21-50) and 41.0 (26-50) years, respectively.Conclusions: Focal concavity of posterior superior acetabulum could be a rare morphologic abnormality of acetabular formation independent of lateral or anterior dysplasia or retroversion. [ABSTRACT FROM AUTHOR]

Rapid destructive arthritis of the hip is a rare entity with unknown pathogenesis and outcome. First described by Forestier in 1957, it is characterized by a rapidly progressive hip disease resulting in rapid destruction of both the femoral and acetabular aspects of the hip joint, with almost complete disappearance of the femoral head within a few months. Since the original description, case reports and small series have been reported, and many names have been proposed to describe the rapid destruction of the femoral head and occasionally the acetabulum. Initial presentation includes acute hip pain with the lack of radiographic evidence of joint destruction, rapidly progressing to complete vanishing of the proximal femur within a few months. This article summarizes the related literature aiming to present the current concepts for the diagnosis and treatment of rapid destructive arthritis of the hip. [ABSTRACT FROM AUTHOR]

Introduction Minimal-invasive placement of screws into the posterior column of the acetabulum (PC) is challenging. Due to the saddle-shaped curvature of the medial cortical border of the PC, the standard fluoroscopic views of the pelvis cannot provide the desired safety during screw insertion. The aim of this study was to define a view tangentially to the medial cortex of the PC and to evaluate its accuracy and inter-observer reproducibility. Methods Radio-dense markers on the medial cortex of the PC along the axis of a PC screw were brought in line and landmarks of the new “Down the PC” view were determined. Kirschner wires were placed into the PC of a pelvis composite model and five pelvic cadaver specimens in a total of 34 different correct and incorrect positions. Based on either only the “Down the PC” view, only the standard views, or a combination of both, three fellowship-trained orthopaedic surgeons had to decide if the inserted wires were in bone in the posterior column or had exited cortex, and if they penetrated the acetabulum. Sensitivity, specificity, and the intra-class correlation coefficient were calculated. Results A view using three radiographic landmarks (pelvic brim, medial cortical wall of the body of the ischium, ischial spine) was found. Sensitivity and specificity to detect perforation out of the bone were 1.00 and 0.97 for the “Down the PC” view, 0.46 and 0.97 if only the standard views were used, and 1.00 and 0.95 for a combination of both. Sensitivity and specificity to detect intra-articular wire placement were 1.00 and 0.96 for the “Down the PC” view, 0.72 and 0.95 if only the standard views were used, and 0.94 and 0.99 for a combination of both. Inter-observer agreement using only the “Down the PC” view was excellent with an ICC of 0.92 for perforation and ICC of 0.82 for intra-articular wire placement. Conclusions The “Down the PC” view is a useful addendum in the orthopaedic trauma surgeon's tool box. Using simple landmarks, it is easily to reproduce and thereby shows excellent accuracy and inter-observer agreement in order to detect medial perforation or intra-articular implant position. [ABSTRACT FROM AUTHOR]

Background: Acetabular reinforcement devices (ARDs) are frequently used as load-sharing devices to allow allograft incorporation in revision hip arthroplasty with massive acetabular bone loss. The key to a successful reconstruction is robust fixation of the device to the host acetabulum. Interlocking fixation is expected to improve the initial stability of the postoperative construct. However, all commercially available ARDs are designed with non-locking fixation. This study investigates the efficacy of standard ARDs modified with locking screw mechanisms for improving stability in acetabular reconstruction. Methods: Three types of ARDs were examined to evaluate the postoperative compression and angular stability: i) standard commercial ARDs, ii) standard ARDs modified with monoaxial and iii) standard ARDs modified with polyaxial locking screw mechanisms. All ARDs were implanted into osteomized synthetic pelvis with pelvic discontinuity. Axial compression and torsion tests were then performed using a servohydraulic material testing machine that measured load (angle) versus displacement (torque). Initial stability was compared among the groups. Results: Equipping ARDs with interlocking mechanisms effectively improved the initial stability at the device/bone interface compared to standard non-locked ARDs. In both compression and torsion experiments, the monoaxial interlocking construct demonstrated the highest construct stiffness (672.6 ± 84.1 N/mm in compression and 13.3 ± 1.0 N·m/degree in torsion), whereas the non-locked construct had the lowest construct stiffness (381.4 ± 117.2 N/mm in compression and 6.9 ± 2.1 N·m/degree in torsion) (P < 0.05). Conclusions: Our study demonstrates the potential benefit of adding a locking mechanism to an ARD. Polyaxial ARDs provide the surgeon with more flexibility in placing the screws at the cost of reduced mechanical performance. This in vitro study provides a preliminary evaluation of biomechanical performance for ARDs with or without interlocking mechanisms, actual clinical trial deserves to be further investigated in future studies. [ABSTRACT FROM AUTHOR]

ABSTRACT Femoral head size provides important information on body size in extinct species. Although it is well-known that femoral head size is correlated with acetabular size, the precision with which femoral head size can be estimated from acetabular size has not been quantified. The availability of accurate 3D surface models of fossil acetabular remains opens the possibility of obtaining accurate estimates of femoral head size from even fragmentary fossil remains [Hammond et al.,: Am J Phys Anthropol 150 (2013) 565-578]. Here we evaluate the relationship between spheres fit to surface models of the femoral head and acetabulum of a large sample of extant anthropoid primates. Sphere diameters are tightly correlated and scale isometrically. In spite of significant taxonomic and possibly functional differences in the relationship between femoral head size and acetabulum size, percent prediction errors of estimated femoral head size remain low regardless of the taxonomic composition of the reference sample. We provide estimates of femoral head size for a series of fossil hominins and monkeys. Am J Phys Anthropol 155:469-475, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Background: Since the original description by Letournel in 1961, the ilioinguinal approach has remained the predominant approach for anterior acetabular fixation. However, modifications of the original abdominal approach described by Stoppa have made another option available for reduction and fixation of pelvic and acetabular fractures. Questions/purposes: We evaluated our results in patients with acetabulum fractures with the modified Stoppa approach in terms of (1) hip function as measured by the Merle d'Aubigne hip score; (2) complications; and (3) quality of fracture reduction and percentage of fractures that united. Methods: Between September 2008 and August 2012, 289 patients with acetabular fractures were treated at our Level I trauma center. Twelve percent (36 of 289) of patients were treated operatively using the modified Stoppa approach. Ninety-seven percent (35 of 36) of our patients had fracture patterns involving displacement of the posterior column. Six (17%) were converted early to a total hip arthroplasty, and 14 (39%) were lost to final followup, leaving 22 of 36 for subjective clinical outcome analysis at a mean of 32 months (range, 9-59 months). Our general indications for this approach during the period in question were fractures of the anterior column and anterior wall, anterior column with posterior hemitransverse fractures, both column fractures, transverse fractures, and T-type fractures. Followup included regularly scheduled office visits with radiographs (AP pelvis, Judet views) that were graded by the treating surgeon and by the authors of this study (MJI, BCT) and patient outcome surveys. Results: Merle d'Aubigne hip scores were very good in 55% (12 of 22), good in 9% (two of 22), medium in 18% (four of 22), fair in 5% (one of 22), and poor in 14% (three of 22), and 70% (23 of 33) of patients were able to ambulate without any assistive devices. Complications included one superficial infection and three deep infections, two patients with temporary lateral thigh numbness, no obturator nerve palsies, and one inguinal hernia. Three deaths in the cohort were seen in followup as a result of unrelated causes. Radiographic grading of fracture reductions after surgery revealed that 27 (75%) were anatomic, six (17%) were satisfactory, and three (8%) were unsatisfactory. A total of 94% of the fractures united. Conclusions: In agreement with prior published data, our results show good functional outcomes with minimal complications using the modified Stoppa approach for a variety of acetabular fractures. Our results highlight the difficulty but feasibility in treating posterior column displacement through an anterior approach. Consideration for dual approaches with posterior column involvement may be warranted to optimize fracture reduction and functional outcomes. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

The article presents a commentary on the article "Acetabular Wall Indices Help to Distinguish Acetabular Coverage in Asymptomatic Adults with Varying Morphologies" which focuses on the examination of the radiographic acetabular morphology among asymptomatic senior athletes. Topics include the measurement of the posterior and anterior femoral head coverage of the hips, the treatment of acetabular overcoverage, and the importance of acetabular morphology measurements for asymptomatic patients.

Periacetabular osteotomy (PAO) is a surgical procedure to correct acetabular orientation in developmental dysplasia of the hip (DDH). It changes the position of the acetabulum to increase femoral head coverage and distribute the contact pressure over the cartilage surface. The success of PAO depends significantly on the surgeon's experience. Using computed tomography data from patients with DDH, we developed a 3D finite element (FE) model to investigate the optimal position of the acetabulum following PAO. A virtual PAO was performed with the acetabulum rotated in increments from the original center edge (CE) angle. Contact area, contact pressure, and Von Mises stress in the femoral and pelvic cartilage were analyzed. Five dysplastic hips from four patients were modeled. Contact area, contact pressure, and Von Mises stress in the cartilage all varied according to the change of CE angle through virtual PAO. An optimal position could be achieved for the acetabulum that maximizes the contact area while minimizing the contact pressure and von Mises stress in the pelvic and femoral cartilage. The optimal position of the acetabulum was patient dependent and did not always correspond to what would be considered a 'normal' CE angle. We demonstrated for the first time the interrelation of correction angle, contact area, and contact pressure between the pelvic and femoral cartilage in PAO surgery. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 472-479, 2013 [ABSTRACT FROM AUTHOR]

Pediatric acetabular fractures are rare, and anterior column fractures are even rarer. Generally, conservative treatment is applied. If there is displacement of more than 2mm or findings of instability or fragments within the joint, then surgical treatment is applied. Anterior and posterior approaches may be used in surgical treatment. With pediatric patients, even greater care should be taken in the choice of surgery to be performed according to the fracture pattern to avoid postoperative triradiate cartilage damage. Therefore, minimally invasive surgery is more appropriate. We herein present a case of an acetabulum anterior column posterior hemitransverse fracture following a traffic accident, which was treated surgically using a modified Stoppa (technique) approach. [ABSTRACT FROM AUTHOR]

Understanding the three-dimensional orientation of the coxo-femoral joint remains a challenge as an accurate three-dimensional orientation ensure an efficient bipedal gait and posture. The quantification of the orientation of the acetabulum can be performed using the three-dimensional axis perpendicular to the plane that passes along the edge of the acetabular rim. However, the acetabular rim is not regular as an important indentation in the anterior rim was observed. An innovative cadaver study of the labrum was developed to shed light on the proper quantification of the three-dimensional orientation of the acetabulum. Dissections on 17 non-embalmed corpses were performed. Our results suggest that the acetabular rim is better represented by an anterior plane and a posterior plane rather than a single plane along the entire rim as it is currently assumed. The development of the socket from the Y-shaped cartilage was suggested to explain the different orientations in these anterior and posterior planes. The labrum forms a plane that takes an orientation in between the anterior and posterior parts of the acetabular rim, filling up inequalities of the bony rim. The vectors VL, VA2 and VP, representing the three-dimensional orientation of the labrum, the anterior rim and the posterior rim, are situated in a unique plane that appears biomechanically dependent. The three-dimensional orientation of the acetabulum is a fundamental parameter to understand the hip joint mechanism. Important applications for hip surgery and rehabilitation, as well as for physical anthropology, were discussed. [ABSTRACT FROM AUTHOR]

Purpose: Acetabular morphology is an important predictor of the severity of osteoarthrosis and survival of hip prostheses but there is limited data on the normal range of acetabular measurements on plain radiographs. The aim of this project was to determine the statistically normal ranges of acetabular inclination (AI) and center-edge angle (CEA).Method: One hundred coronal CT localizers (50 men and 50 women aged 20-30 years) were included in this study. All the patients underwent CT examination for thoracic or intra-abdominal indications. Patients with pelvic disease, fractures, history of serious trauma, or previous pelvic surgery were excluded. One pair of independent observers measured the AI and pelvic tilt (PT), and a further pair measured the center-edge angle (CEA), using electronic calipers on a high-resolution PACS workstation.Results: AI and CEA measurements were obtained for 200 hips. There was very good intra-class correlation between the observers (r = 0.7-0.8). The mean AI was 38.8° (2SD 32.1-45.5°). That in men was 38.0° (2 SD 31.8-44.1°) and 39.6° (2 SD 32.7-46.8°) in women, which was statistically significantly different (p < 0.001). The mean CEA measurement for all patients was 36.3° (SD 13.8°), for men 37.7° (SD 10.8°) and for women 34.9° (SD 11.4°) with a statistically significant gender difference (p < 0.001). The mean pelvic tilt measurement (sacro-coccygeal-pubic symphysis) was 38.3 mm (2 SD 18.3-58.3 mm) with a significant gender difference (p < 0.001).Conclusions: The results of this study define reference ranges of two common measures of acetabular morphology and confirm statistically significant differences between men and women. [ABSTRACT FROM AUTHOR]

Background: Acetabular retroversion has been identified in mature patients with sequelae of Legg-Calvé-Perthes (LCP) disease. Whether this is a contributing etiologic factor that leads to the disease process or result of the head deformity is not known. The prominence of the ischial spine (PRIS) sign, which reflects retroversion, can be observed before ossification of the anterior and posterior walls in a skeletally immature patient and could help determine whether the retroverted acetabulum is present before or after head involvement in patients with LCP disease. Questions/purpose: We therefore determined (1) the prevalence of the PRIS sign in patients with LCP disease compared with healthy control subjects, (2) whether the PRIS sign is seen at the time of head involvement in patients with LCP disease, and (3) the prevalence of bilaterality of the PRIS sign in patients with LCP disease and control subjects. Patients and Methods: Of 295 patients with LCP disease, 47 (49 hips) met our inclusion criteria. Of these, 39 (41 hips) had open triradiate cartilage and comprised the study group. Twenty-five pediatric patients with polytrauma (50 hips) with standardized radiographs comprised the control group. Results: A positive PRIS sign was noted in 37 of the 41 skeletally immature hips compared with only 16 of the 50 control hips. We observed a positive PRIS sign early in the LCP disease process with eight of nine patients in the fragmentation phase having a positive PRIS sign. The PRIS sign was seen bilaterally in 25 of 39 patients with unilateral LCP disease and in only five of 25 control patients. Conclusions: Acetabular retroversion, as evidenced by a positive PRIS, was present in nine of 10 children with LCP disease. It is uncertain if retroversion is a cause or a sequela of the disease, but it was seen early in the disease process at the time of head involvement in the majority of patients. Level of Evidence: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Neglected hip dislocation is a rare situation among children. The coexistence of acetabulum fracture is less common. The result of treatment depends on the time of diagnosis. Early treatment is mandatory in such cases. Seven years old female brought to our outpatient clinic with the complaints of right hip pain and walking difficulty. Her parents said that she had fallen from a horse one month ago. X-ray and CT showed a posterior dislocation of her right hip and a fracture on her right posterior acetabular lip. We performed an open reduction via posterior approach. Because the hip was unstable we fixed the femoral head to the acetabulum by a Kirshner wire. Pelvipedal cast was applied after the operation for 6 weeks. After 6 months avascular necrosis (AVN) developed on her right femoral head, the range of motion (ROM) of the hip was restricted and she had minimal pain on her right hip. [ABSTRACT FROM AUTHOR]

Dislocation is the second most common complication in total hip arthroplasty, with reported incidences of up to 8 per cent. The authors' hypothesis is that, by modifying the rim of an acetabular component in order to shift the femoral neck contact position towards the periphery of the acetabulum, the torque required to dislocate the hip joint can be increased without reducing the range of motion. Three liners were designed and their dislocation characteristics mechanically evaluated using a custom experimental test jig designed to simulate the seated leg-cross. On the basis of torque and energy to dislocate and angle at dislocation, the hypothesis was accepted; geometrically varying the contact area between the femoral neck and the acetabular rim appear to be a powerful way to modify hip dislocation characteristics. [ABSTRACT FROM AUTHOR]

Background: Eccentric rotational acetabular osteotomy for the operative treatment of acetabular dysplasia consists of a spherical but eccentric osteotomy and rotation of the acetabulum that moves the center of rotation of the head of the femur medially and distally. No bone graft is needed. The reorientation of the acetabular fragment not only improves acetabular coverage but also restores the center of rotation of the subluxated hip. The purpose of this paper was to describe eccentric rotational acetabular osteotomy for the treatment of acetabular dysplasia and to evaluate its clinical and radiographic outcomes.Methods: We performed this procedure consecutively in 132 hips in 126 patients with dysplasia of the hip. Eighteen hips had no osteoarthritis, fifty-three had early osteoarthritis, and sixty-one had advanced osteoarthritis. Seven patients were male, and 119 were female. The average age was 36.5 years at the time of the index operation, and the average duration of follow-up was 7.5 years. Twenty-three hips in twenty-two patients were also treated with intertrochanteric valgus osteotomy to further improve joint congruency at the time of the acetabular osteotomy.Results: The average preoperative Harris hip score of 71 points improved to an average score of 89 points at the time of the latest follow-up. The average center-edge angle improved from 0 to 36 . An apparent change in the stage of the arthritis was observed in seven hips (5%), one of which had had early-stage disease and six of which had had advanced disease preoperatively.Conclusions: Eccentric rotational acetabular osteotomy appears to be a good treatment option for young patients with either early or advanced hip osteoarthritis secondary to dysplasia. [ABSTRACT FROM AUTHOR]

With carbon particles we analyzed patterns of growth in Acetabularia acetabulum (Lam.) P.C. Silva, a giant unicell famous for classic development studies. We focussed on the stalk apex, which generates the stalk, whorls of hairs, and whorls of gametophores. To gain visual and physical accessibility, we amputated the youngest whorls of hairs and the original apex and performed experiments on the apex that regenerated. Video analysis indicated that most growth occurred near the tip of the new apex. Less growth occurred throughout the cut-interwhorl. We also analyzed cell wall thickness along stalks cleared of cytoplasm. Correlating growth data to wall morphology suggests growth near the apex may be proportional to stress on the cell wall. We propose that turgor-pressure wall stress modulates local apical cell wall growth rates. A supplementary model, relating cell wall curvature and growth rate in the cut-interwhorl, characterizes how the stalk's final dimensions and nearly cylindrical shape may arise. See http://faculty.washington.edu/mandoli/vondassow for supplementary data, analysis, and mathematical appendices. We believe this is the first quantitative description of apex morphogenesis of A. acetabulum. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the MR imaging characteristics of normal acetabular labra on both hips. Three hundred sixty acetabular labra on both hips of 180 asymptomatic volunteers were examined on a 0.5-T MR unit utilizing a superficial coil. T1-weighted and T2-weighted gradient-echo sequences (TR/TE/FA 169/10 ms/40 degrees, and 316/25 ms/40 degrees, respectively) were used. The volunteers were classified into five age groups (10-19, 20-29, 30-39, 40-49, and 50 + years of age). The shape (triangular, flat, round, absent), size, and the presence of intralabral foci of increased intensity (diffuse, linear, central, or basal) were noted on both labra in each volunteer, and symmetry-asymmetry of these features were investigated. The most common labrum shape was triangular, whereas absence of labrum was the least common condition. A difference of labral shapes between both hips was present in approximately 15% of volunteers. A size difference of over 25% between each labrum was noted in approximately one-fourth of volunteers. An age-related pattern of intralabral intensity increase was noted on both MR sequences (more commonly on T1-weighted gradient-echo images). Shape differences and age-related intensity changes of the acetabular labrum in the MR imaging of the hips were confirmed, and the possibility of variability of the labra, with regard to the shape and size, on both hips of the same individual was documented. [ABSTRACT FROM AUTHOR]