Acetabular Rotation Research Articles

A prospective and consecutive study assessing short-term clinical and radiographic outcomes of Chinese domestically manufactured 3D printing trabecular titanium acetabular cup for primary total hip arthroplasty: evaluation of 236 cases.

We prospectively evaluate the short-term clinical and radiographic outcomes of the only Chinese domestically produced trabecular titanium acetabular cup(3D ACT™ cup) in primary total hip arthroplasty (THA), aiming to provide evidence-based support for its clinical application. A total of 236 patients, who underwent primary THA using 3D ACT™ cup in the Department of Joint Surgery at our hospital between January 2017 and June 2019, were included in this study. General patient data, imaging information, functional scores, and complications were collected to evaluate the early clinical efficacy. All patients were followed up for 33-52 months, with an average of (42.2 ± 9.2) months. At the last follow-up, the preoperative HHS score increased significantly from 43.7 ± 6.8 to 85.6 ± 9.3 points (P < 0.01). Similarly, the preoperative WOMAC scores showed significant improvement from 59.2 ± 5.8 to 13.1 ± 3.5 points (P < 0.01). 92.3% of the patients expressed satisfaction or high satisfaction with the clinical outcome. Furthermore, 87.7% of the acetabular cups were positioned within the Lewinnek safe zone, achieving successful reconstruction of the acetabular rotation center. The cup survival rate at the last follow-up was 100%. The utilization of the only Chinese domestically manufactured 3D printing trabecular titanium acetabular cup in primary THA demonstrated favorable short-term clinical and radiographic outcomes. The acetabular cup exhibits excellent initial stability, high survival rate, and favorable osseointegration, leading to a significant enhancement in pain relief and functional improvement. In the future, larger sample sizes and multicenter prospective randomized controlled trials will be required to validate the long-term safety and effectiveness of this 3D ACT™ cup.

Poster 118: False Profile Radiograph Sourcil-Edge and Bone-Edge Measurements Both Correlate to Different Weight-Bearing Regions of the Acetabulum: A Three-Dimensional Analysis

Objectives: The acetabular sourcil has been thought of as the radiographic representation of the weightbearing dome of the acetabulum; however, there are limited modern data to support this supposition. In the literature, assessment of weightbearing acetabular coverage has been described using both the sourcil-edge and bone-edge as anatomic landmarks, leading to confusion and controversy in classification of hip dysplasia, indications for hip preservation surgery, and intraoperative coverage assessment. The purpose of this study was to localize the three-dimensional (3D) anatomic correlates of the sourcil-edge and bone-edge radiographic position on false profile radiographs. The authors hypothesized that the sourcil-edge on the false profile represents anterolateral coverage while the bone-edge represents anterior coverage. Methods: Forty hips were grouped by large or small differences between bone-edge and sourcil-edge anterior center edge angles (ACEA). The small difference group comprised the lowest quartile of sourcil-edge to bone-edge difference of an initial cohort of 80 hips, while the large difference group comprised the highest quartile of difference. 3D surface mesh models and digitally reconstructed radiographs (DRRs) were generated from hip computed tomography scans using the 3D Slicer Image Computing Platform (Figures 1 &amp; 3). Sourcil-edge, bone-edge, and ACEAs were identified on DRRs and registered to the 3D models with fiducial markers. Intersection of bone-edge and sourcil-edge projection lines with the acetabular rim were obtained from the 3D models (Figures 2 &amp; 4). 3D Anterior acetabular rim morphology was correlated with ACEA difference. Results: The bone-edge and sourcil-edge projections intersected the acetabular rim at a mean of 2:08 ± 0:25 and 1:20 ± 0:24 o’clock, respectively. The 3D models consistently demonstrated that, in both large and small discrepancy groups, the sourcil-edge corresponded to an area just posterior to the AIIS projection while the bone-edge corresponded to the weight-bearing region inferior to the AIIS (Figures 2 &amp; 4). Additionally, in large discrepancy hips, the bone-edge corresponded to a more prominent acetabular coverage in the region of the AIIS than when compared to the small discrepancy hips. Conclusions: This study demonstrates that both the sourcil-edge and bone-edge projections on false profile radiographs correlate with differing weightbearing regions of the acetabulum. The sourcil-edge ACEA represents coverage at 1:20 o’clock on the acetabular rim and is consistently posterior to the AIIS, while the bone-edge measurement represents the region of the acetabular rim at 2:08 o’clock and is consistently inferior to the AIIS. In hips with a large discrepancy between bone-edge and sourcil-edge (highest quartile), ACEA measurement differs by a mean of 19.7 degrees based on the selection of these radiographic landmarks. These findings have substantial implications for hip preservation surgery technique and clinical decision making. A comprehensive understanding of femoral head coverage is essential for the treatment of young adult hip pathology. Although the sourcil and bone edge are two of the most important radiographic landmarks for assessment of acetabular dysplasia, descriptions of these landmarks are often over simplified. Some authors have advocated for greater utilization of measurements of coverage to the bone edge as it can be more consistently identified. Other authors have advocated for utilizing the sourcil-edge measurement as this is more representative of the “weight bearing dome”. These descriptions are limited as they do not improve our understanding of the anatomic and radiographic structure of the anterior acetabular rim. Although the concept of the “weight bearing dome” is classically described, it lacks anatomic precision. The present study clarifies the anatomic features of the acetabular rim that correspond to these radiographic features. Increased difference between the sourcil-edge and bone edge is generated by the differences in undulation of the anterosuperior acetabular rim. Acetabuli that have maximal anterior rim prominence at or near the superior-most aspect of the acetabulum (generally counterclockwise from the AIIS) tend to demonstrate smaller discrepancy between the bone-edge and sourcil-edge (Figure 4). Acetabuli that have maximal rim prominence medial and anterior to the superior-most aspect of the acetabulum generally demonstrate larger discrepancy (Figure 2). The present anatomic description can be utilized by the hip arthroscopist to better determine which areas of the anterior rim may cause impingement. Similarly, while conducting a periacetabular osteotomy, the surgeon may use this information to better understand how acetabular rotation is contributing to both anterior and anterolateral coverage. In conclusion, on false profile radiographs, the sourcil-edge corresponds to superior femoral head coverage, while the bone-edge corresponds to anterosuperior coverage. False profile radiographs with a large discrepancy between sourcil-edge and bone-edge measurements demonstrate a prominent weight bearing surface in the region of the AIIS. These data regarding the radiographic phenomena of the acetabular rim can aid in clinical decision-making and intraoperative technique.

Facteurs influençant la reprise du sport après ostéotomie acétabulaire rotationnelle excentrique

BackgroundAlthough eccentric acetabular rotation osteotomy (ERAO) is an effective treatment for developmental dysplasia of the hip (DDH), there is little information about return to sports after ERAO. This study aimed to investigate 1) the patient factors that influence the return to sports after ERAO, 2) whether postoperative sports participation will affect future osteoarthritis progression. HypothesisSome factors affect the return to sports after ERAO. Patients and methodsOf 503 patients who underwent ERAO from 1990 to 2010, 124 who had been continuously participating in sports preoperatively (average 13.2 years after surgery) were included. Patient demographics of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative Kellgren-Lawrence (KL) grade, center edge angle, joint congruency, Harris hip score, complications and the survival rate were compared between the S group (patients who participated in the same sports preoperatively) and N group (patients who could not participate in sports postoperatively). ResultsSeventy-two (58%) and 52 patients (42%) in the S and N groups, respectively, had an overall return to sports rate of 64% (79 patients). The most common sports that patients participated in were swimming (30 patients [24%]), jogging (12 [10%]), and golf (10 [8%]) preoperatively, and swimming (14 patients [11%]), golf (8 [6%]), and jogging (8 [6%]) postoperatively. There were no significant differences between both groups in terms of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative KL grade, and joint congruency. There was a significant difference in patient factors between the S (11 joints [14%]) and N (20 joints [38%]) groups only when the preoperative center edge angle was <0°. There was no significant difference in the preoperative Harris hip score and the final survey between the S (73.2±4.6 and 93.4±7.2) and N (72.5±4.8 and 92.1±7.4) groups. Complications showed no significant differences between the five patients (7%) in the S group and six patients (13%) in the N group. The KL grade progressed in 10 cases (grade II to III in 2 cases and grade III to IV in 8) in the S group and 8 cases (grade II to III in 1 case and grade III to IV in 7 cases) in the N group. The 10-year and 20-year joint survival rates with THA conversion as the endpoint were 98.1% (95% CI: 87.4%–99.7%) and 83.7% (95% CI: 62.6%–93.4%) in the S group and 100% (95% CI: 70.7%–99.3%) and 95.2% (95% CI: 12.6%–92.6%) in the N group, respectively. In the evaluation of factors affecting sports return by logistic regression analysis, only one significant factor (odds ratio 3.42, 95% confidence interval: 1.58–7.42, p<0.01) was the preoperative center edge angle <0°. DiscussionThe chief factor affecting the return to sports after surgery was a preoperative center edge angle <0°; moreover, the continuation of sports did not affect the subsequent progression of osteoarthritis or THA conversion. Level of evidenceLevel III, cohort study.

Factors affecting return to sports after eccentric rotational acetabular osteotomy

BackgroundAlthough eccentric acetabular rotation osteotomy (ERAO) is an effective treatment for developmental dysplasia of the hip (DDH), there is little information about return to sports after ERAO. This study aimed to investigate 1) the patient factors that influence the return to sports after ERAO, 2) whether postoperative sports participation will affect future osteoarthritis progression. HypothesisSome factors affect the return to sports after ERAO. Patients and methodsOf 503 patients who underwent ERAO from 1990 to 2010, 124 who had been continuously participating in sports preoperatively (average 13.2 years after surgery) were included. Patient demographics of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative Kellgren-Lawrence (KL) grade, center edge angle, joint congruency, Harris hip score, complications and the survival rate were compared between the S group (patients who participated in the same sports preoperatively) and N group (patients who could not participate in sports postoperatively). ResultsSeventy-two (58%) and 52 patients (42%) in the S and N groups, respectively, had an overall return to sports rate of 64% (79 patients). The most common sports that patients participated in were swimming (30 patients [24%]), jogging (12 [10%]), and golf (10 [8%]) preoperatively, and swimming (14 patients [11%]), golf (8 [6%]), and jogging (8 [6%]) postoperatively. There were no significant differences between both groups in terms of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative KL grade, and joint congruency. There was a significant difference in patient factors between the S (11 joints [14%]) and N (20 joints [38%]) groups only when the preoperative center edge angle was <0°. There was no significant difference in the preoperative Harris hip score and the final survey between the S (73.2±4.6 and 93.4±7.2) and N (72.5±4.8 and 92.1±7.4) groups. Complications showed no significant differences between the five patients (7%) in the S group and six patients (13%) in the N group. The KL grade progressed in 10 cases (grade II to III in 2 cases and grade III to IV in 8) in the S group and 8 cases (grade II to III in 1 case and grade III to IV in 7 cases) in the N group. The 10-year and 20-year joint survival rates with THA conversion as the endpoint were 98.1% (95% CI: 87.4%–99.7%) and 83.7% (95% CI: 62.6%–93.4%) in the S group and 100% (95% CI: 70.7%–99.3%) and 95.2% (95% CI: 12.6%–92.6%) in the N group, respectively. In the evaluation of factors affecting sports return by logistic regression analysis, only one significant factor (odds ratio 3.42, 95% confidence interval: 1.58–7.42, p<0.01) was the preoperative center edge angle <0°. DiscussionThe chief factor affecting the return to sports after surgery was a preoperative center edge angle <0°; moreover, the continuation of sports did not affect the subsequent progression of osteoarthritis or THA conversion. Level of evidencelevel III, cohort study.

The significance of the Dega osteotomy.

Wiktor Dega has significantly impacted contemporary pediatric orthopedics by developing transiliac osteotomy - Dega's pelvic osteotomy. The global implementation of the surgery technique gained dynamism in the 2000s after being published by Ward and Grudziak. Since then, derivative operative techniques called Dega, Dega-like or Dega family osteotomies have been developed. We analyzed the original articles published by Dega between 1929 and 1974 concerning transiliac osteotomy technique development and articles about its derivatives. The epidemiological significance of developmental hip dysplasia focused Wiktor Dega's attention in the 1920s. At that time, he treated patients according to König's idea of acetabular roof plastic surgery. The osteotomy depth gradually increased, which allowed deeper graft placement to perform what we nowadays call acetabuloplasty. In 1958, Dega coined the name 'supraacetabular semicircular osteotomy'. It differed from the final concept of the transiliac osteotomy by not assuming the cut of the inner cortex of the iliac bone. The hinge for the acetabular rotation was located at the inner cortex's whole length, disallowing the excessive redirection. The final concept of osteotomy allows for simultaneous acetabuloplasty and redirection to change the shape, location and acetabular volume. Dega derivatives are Mubarak (San Diego) and high Dega osteotomies. Dega osteotomy and its derivates are routinely implemented to treat developmental hip dysplasia and spastic hip disorders. It might be considered an option in Legg-Calve-Perthes disease, congenital deficiencies, and flaccid hip displacement in neurological conditions.

Application of personalized digital analog assisted acetabular prosthesis precise implantation in Crowe typeⅠand Ⅱ hip dysplasia

To explore the effect of personalized digital analog assisted acetabular prosthesis precise implantation in hip dysplasia. From February 2017 to July 2019, 11 patients(12 hips) with hip dysplasia underwent total hip arthroplasty, including 4 males(5 hips) and 7 females(7 hips), aged from 27 to 61 years old, with an average of (46.64±12.93) years old;Crowe classification:8 hips in typeⅠ and 4 hips in typeⅡ. The preoperative thin-layer CT scan was imported into Mimics 10.01 software. The appropriate size and placement angle of acetabular prosthesis were selected through preoperative simulation, and the acetabular bone defect was understood to determine whether structural bone grafting was needed during the operation. The length of both lower limbs, the anteversion angle of acetabular prosthesis, the abduction angle, the height of acetabular rotation center and the horizontal distance of hip joint center before and after the operation were measured, and the postoperative dislocation, bone graft healing and acetabular cup loosening were observed. The hip Harris score was used to evaluate the joint function. All patients were followed up for 18 to 30 months with an average of (23.45±3.70) months. There was no prosthesis dislocation, loosening and bone graft healing after operation. One case had numbness in the innervation area due to the traction of sciatic nerve during operation, and was treated with neurotrophic drugs and recovered one month after operation. The length difference of both lower limbs decreased from (31.73±5.98) mm before operation to (4.73±1.90) mm 3 months after operation (t=15.268, P<0.01). The anteversion angle of acetabular cup and acetabulum was (17.45±3.62)°and abduction angle was (40.10 ± 2.30)° after operation. In all cases, the abduction angle and anteversion angle were within the safe range of Lewinek. The height of hip rotation center was (20.64±2.58) mm and the horizontal inward displacement of hip was (33.46±3.61) mm. Harris score increased from (45.36±2.34) before operation to (91.27±2.37) 3 months after operation (P<0.05). Through preoperative personalized digital analog reconstruction of acetabulum in patients with hip dysplasia, we can better understand the acetabular defect, help to evaluate the size and placement angle of acetabular prosthesis and whether structural bone grafting is needed, and obtain satisfactory clinical curative effect.

Effectiveness of total hip arthroplasty in patients with a history of hip preservation surgery with secondary osteoarthritis for developmental dysplasia of the hip

To evaluate early to medium-term effectiveness of total hip arthroplasty (THA) in patients with a history of hip preservation surgery with secondary severe osteoarthritis for developmental dysplasia of the hip (DDH). The clinical data of 25 DDH patients (31 hips) who had severe osteoarthritis after hip preservation surgery and received THA between September 2009 and March 2021 were retrospectively analyzed. There were 1 male and 24 females; the age ranged from 18 to 65 years, with an average age of 43 years; 8 hips were classified into Crowe type Ⅰ, 9 hips were type Ⅱ, 3 hips were type Ⅲ, and 11 hips were type Ⅳ. The time between osteotomy and THA ranged from 31 to 51 years, with an average of 31.96 years. Preoperative hip flexion range of motion was (69.31±29.72)°, abduction range of motion was (24.00±14.79)°; and Harris hip score was 45.3±15.5. Postoperative Harris hip score, hip range of motion, complications, radiographic findings, and implant survival rate were analyzed. Patients in both groups were followed up 2-132 months, with an average of 51 months. During the follow-up, periprosthetic fracture occurred in 1 case; there was no complication such as dislocation, periprosthetic infection, nerve palsy, or deep vein thrombosis. At last follow-up, the hip flexion range of motion was (109.52±11.17)°, abduction range of motion was (41.25±5.59)°, showing significant differences when compared with preoperative values ( t=8.260, P=0.000; t=6.524, P=0.000). The Harris hip score was 91.5±4.1, and the difference was significant when compared with preoperative score ( t=11.696, P=0.000); among them, 13 cases were excellent and 12 cases were good. Radiographic evaluation showed that the center of acetabular rotation moved up 0-18 mm (mean, 6.35 mm). The cup abductor angle was 28°-49° (mean, 37.74°) and the coverage rate was 69.44%-98.33% (mean, 81.04%). All femoral stems were fixed in neutral position without varus or valgus. No osteolysis, radiolucent line, or implant migration was observed. By the end of follow-up, none of the patients underwent revision and the survival rate of prothesis was 100%. THA is still the gold standard for the treatment of DDH patients with secondary osteoarthritis after hip preservation surgery. The postoperative joint function can be rapidly restored, the patients' quality of life can significantly improve, and the early to medium-term survival rate of the prosthesis is satisfactory.

Is Anterior Rotation of the Acetabulum Necessary to Normalize Joint Contact Pressure in Periacetabular Osteotomy? A Finite-element Analysis Study.

Inappropriate sagittal plane correction can result in an increased risk of osteoarthritis progression after periacetabular osteotomy (PAO). Individual and postural variations in sagittal pelvic tilt, along with acetabular deformity, affect joint contact mechanics in dysplastic hips and may impact the direction and degree of acetabular correction. Finite-element analyses that account for physiologic pelvic tilt may provide valuable insight into the effect of PAO on the contact mechanics of dysplastic hips, which may lead to improved acetabular correction during PAO. We performed virtual PAO using finite-element models with reference to the standing pelvic position to clarify (1) whether lateral rotation of the acetabulum normalizes the joint contact pressure, (2) risk factors for abnormal contact pressure after lateral rotation of the acetabulum, and (3) whether additional anterior rotation of the acetabulum further reduces contact pressure. Between 2016 and 2020, 85 patients (92 hips) underwent PAO to treat hip dysplasia. Eighty-two patients with hip dysplasia (lateral center-edge angle < 20°) were included. Patients with advanced osteoarthritis, femoral head deformity, prior hip or spine surgery, or poor-quality images were excluded. Thirty-eight patients (38 hips) were eligible to participate in this study. All patients were women, with a mean age of 39 ± 10 years. Thirty-three women volunteers without a history of hip disease were reviewed as control participants. Individuals with a lateral center-edge angle < 25° or poor-quality images were excluded. Sixteen individuals (16 hips) with a mean age of 36 ± 7 years were eligible as controls. Using CT images, we developed patient-specific three-dimensional surface hip models with the standing pelvic position as a reference. The loading scenario was based on single-leg stance. Four patterns of virtual PAO were performed in the models. First, the acetabular fragment was rotated laterally in the coronal plane so that the lateral center-edge angle was 30°; then, anterior rotation in the sagittal plane was added by 0°, 5°, 10°, and 15°. We developed finite-element models for each acetabular position and performed a nonlinear contact analysis to calculate the joint contact pressure of the acetabular cartilage. The normal range of the maximum joint contact pressure was calculated to be < 4.1 MPa using a receiver operating characteristic curve. A paired t-test or Wilcoxon signed rank test with Bonferroni correction was used to compare joint contact pressures among acetabular positions. We evaluated the association of joint contact pressure with the patient-specific sagittal pelvic tilt and acetabular version and coverage using Pearson or Spearman correlation coefficients. An exploratory univariate logistic regression analysis was performed to identify which of the preoperative factors (CT measurement parameters and sagittal pelvic tilt) were associated with abnormal contact pressure after lateral rotation of the acetabulum. Variables with p values < 0.05 (anterior center-edge angle and sagittal pelvic tilt) were included in a multivariable model to identify the independent influence of each factor. Lateral rotation of the acetabulum decreased the median maximum contact pressure compared with that before virtual PAO (3.7 MPa [range 2.2-6.7] versus 7.2 MPa [range 4.1-14 MPa], difference of medians 3.5 MPa; p < 0.001). The resulting maximum contact pressures were within the normal range (< 4.1 MPa) in 63% of the hips (24 of 38 hips). The maximum contact pressure after lateral acetabular rotation was negatively correlated with the standing pelvic tilt (anterior pelvic plane angle) (ρ = -0.52; p < 0.001) and anterior center-edge angle (ρ = -0.47; p = 0.003). After controlling for confounding variables such as the lateral center-edge angle and sagittal pelvic tilt, we found that a decreased preoperative anterior center-edge angle (per 1°; odds ratio 1.14 [95% CI 1.01-1.28]; p = 0.01) was independently associated with elevated contact pressure (≥ 4.1 MPa) after lateral rotation; a preoperative anterior center-edge angle < 32° in the standing pelvic position was associated with elevated contact pressure (sensitivity 57%, specificity 96%, area under the curve 0.77). Additional anterior rotation further decreased the joint contact pressure; the maximum contact pressures were within the normal range in 74% (28 of 38 hips), 76% (29 of 38 hips), and 84% (32 of 38 hips) of the hips when the acetabulum was rotated anteriorly by 5°, 10°, and 15°, respectively. Via virtual PAO, normal joint contact pressure was achieved in 63% of patients by normalizing the lateral acetabular coverage. However, lateral acetabular rotation was insufficient to normalize the joint contact pressure in patients with more posteriorly tilted pelvises and anterior acetabular deficiency. In patients with a preoperative anterior center-edge angle < 32° in the standing pelvic position, additional anterior rotation is expected to be a useful guide to normalize the joint contact pressure. This virtual PAO study suggests that biomechanics-based planning for PAO should incorporate not only the morphology of the hip but also the physiologic pelvic tilt in the weightbearing position in order to customize acetabular reorientation for each patient.

Does robotic assisted technology improve the accuracy of acetabular component positioning in patients with DDH?

Accurate positioning of the acetabular component is key in performing total hip arthroplasty (THA). However, reconstruction of the acetabulum in the setting of developmental dysplasia of the hip (DDH) is a challenge. Robotic assisted THA has the potential to improve the accuracy of implantation of the acetabular cup in cases with DDH. The purpose of this study was to assess whether robotic technology improves the accuracy of acetabular component positioning in patients with DDH. We included 59 THAs using robotic assisted technology from June 2019 to January 2020 as the study group. These were compared to conventional THAs without robotic technology after control for age, gender, body mass index (BMI), Crowe type and operation date. Radiographic measurements were taken by 2 blinded orthopaedic residents. The percentage of hips within the Lewinnek and Collanan safe zones were calculated, along with acetabular rotation centers for the "target zone." Surgical time and perioperative bleeding were also compared between both groups. One patient suffered dislocation in conventional group while no dislocation occurred in robotic group. The acetabular components of the robotic assisted group had more cases located within the Lewinnek (p = 0.013) and Collanan (p = 0.008) safe zones than conventional group (94.9% vs 79.7% and 74.6% vs 50.8%). There were 7 cases in conventional group and 4 cases in robotic group that had more lateral or more superior rotational centers of THA, but did not reach statistical significance (p = 0.342). No statistical difference was detected between groups with regards to blood loss (p = 0.098) and surgical time (p = 0.602). Robot assisted technology can assist surgeons with implanting acetabular cups more in Lewinnek and Callanan safe zone than conventional techniques without additional blood loss and surgical time. Therapeutic Level Ⅲ.

Proximal femoral changes related to obesity: an analysis of slipped capital femoral epiphysis pathoanatomy.

Recent research has revealed the importance of the femoral epiphyseal tubercle and cupping height in the stability of the physis and its association with capital femoral slippage. To better understand the connection between the pathogenesis of slipped capital femoral epiphysis and obesity, we performed a retrospective analysis of proximal femur and acetabular anatomies using computed tomography (CT) scans in the hips of normal weight and obese pediatric patients. We measured morphologic characteristics of the proximal femur and acetabulum in developing hips of 31 obese adolescent patients and age-matched and sex-matched control group using pelvic CT scans. Measurements included physeal diameter, tubercle height, width, and volume, cupping height, acetabular rotation and inclination, and metaphyseal bone density. Measurements were performed on true coronal and sagittal views through the center of the epiphysis using previously described and validated techniques. Statistical analysis was performed to compare the measurements between obese and nonobese adolescents. The epiphyseal tubercle volume and average cupping size were similar between the two groups. Acetabular inclination and metaphyseal bone density were significantly different between the cohorts. Metaphyseal bone density was lower among obese patients. Obesity does not appear to cause morphologic changes to the capital femoral physis, though it is associated with a decreased metaphyseal bone mineral density which could indicate physeal instability. This could suggest increased metabolic activity in the metaphyseal bone in obese adolescents. Therefore, metabolic factors associated with obesity, rather than anatomical changes, may be responsible for physeal instability seen in obese adolescents.

Application of computer aided design 3D printed navigation template in Salter pelvic osteotomy for dislocation of hip joint in children

Objective To explore the feasibility of accurate localization for the acetabular direction in Salter pelvic osteotomy for the developmental dislocation of the hip joint in children by using computer aided design and 3D printing technique. Methods The clinical data of 12 patients of unilateral hip dislocation treated with Salter pelvic osteotomy by using 3D printed navigation template in Department of Orthopedics, Children′s Hospital of Nanjing Medical University From October 2016 to April 2017 were retrospectively analyzed.Among the 12 cases, there were 4 males and 8 females, 5 hips on the left and 7 hips on the right, aged 1.5 to 5.0 years old (mean 2.3 years old). According to the CT data, the models of the healthy hip joint were mirrored to the contralateral side by Mimics software.Computer-aided simulations of Salter pelvic osteotomy on models of the affected hip joints were performed.Then, the models of the affec-ted hip joint were rotated to the mirror models of the contralateral hip joint.The navigation templates were designed according to the exposed pelvic surface morphology during the operation.The navigation templates were printed by rapid prototyping technology to guide the operation.Preoperative and postoperative acetabular index (AI) and center edge angle (CEA) of affected side were compared to postoperative AI and CEA of contralateral side respectively. Results A method of making personalized navigation templates for Salter pelvic osteotomy was established in 12 children with developmental dislocation of the hip joint.The operation time ranged from 40.2 to 64.5 min, averaging (50.6±8.5) min.The intraoperative bleeding volume ranged from 35 to 60 mL, averaging 52 mL.No vascular and nerve injury was found in the postoperative examination, and no child had complications such as infection, residual foreign body of the guide plate and so on.There was significant difference in preoperative measurements regarding AI between the affected side [(38.4±2.8)°] and the contralateral side [(21.6±0.8)°](t=-18.77, P 0.05), there was no significant difference in postoperative measurements regarding CEA between the affected side[(21.2±2.6)°] and the contralateral side(t=-0.435, P>0.05). Conclusions The navigation template prepared by computer aided design and 3D printing technology has good accuracy, and is a new approach to accurate acetabular rotation in children with the developmental dislocation of the hip joint for Salter pelvic osteotomy. Key words: Dislocation of hip joint; Osteotomy; 3D printing

Is lateral acetabular rotation sufficient to correct anterolateral deficiency in periacetabular reorientation osteotomy? A CT-Based simulation study

BackgroundResidual acetabular deficiency after periacetabular reorientation osteotomy can result in suboptimal outcome. The optimal algorithm of acetabular fragment correction to achieve normal anterolateral acetabular coverage is not well characterized. The aim of this study was to determine the prevalence of residual anterolateral deficiency after lateral acetabular rotation and to evaluate the ability of additional sagittal and axial rotation of the acetabulum to normalize the acetabular coverage in periacetabular osteotomy. MethodsWe performed computed tomography-based simulated periacetabular osteotomy on 85 patients (85 hips) with hip dysplasia. The acetabular fragment was rotated laterally to achieve a lateral center-edge angle (CEA) of 30°. For hips with residual anterolateral deficiency, which were identified based on the reference interval of the anterior CEA, the acetabulum was further rotated in the sagittal or axial direction in 5-degree increments from 5° to 20°, and the ability of these two manoeuvres to restore a normal anterior CEA was assessed. ResultsAfter lateral acetabular rotation, 16 hips (19%) had residual anterolateral deficiency, 67 hips (79%) had normal acetabular coverage, and 2 hips (2.4%) had acetabular overcoverage. A preoperative anterior CEA <37° predicted residual deficiency (sensitivity, 94%; specificity, 81%). Additional anterior sagittal rotation was more effective than posterior axial rotation in normalizing the anterior CEA, while minimizing the decrease in posterior CEA. The highest number of hips with normal anterior and posterior CEA was noted at 10° sagittal rotation (81%), which was followed by 15° sagittal rotation (63%). ConclusionsNormal anterolateral coverage was achieved in 79% of patients after rotating the acetabulum laterally. However, lateral rotation of the acetabulum may be insufficient to correct the anterolateral deficiency in patients with an anterior CEA of <37°. In them, additional 10°–15° anterior sagittal rotation may be appropriate to achieve sufficient anterolateral coverage while retaining posterolateral coverage.

Prevalence of Radiographic Morphology of Femoroacetabular Impingement in Indian Population: A Multicenter Study

BackgroundFemoroacetabular impingement (FAI) is an overlooked entity in India, as primary osteoarthritis of hip is uncommon in Indian population. The purpose of this study is to find out the prevalence of radiographic morphology of FAI in young asymptomatic population in India. MethodsThis is a multicenter, cross-sectional study. Radiographs of 500 young asymptomatic volunteers were taken from 10 centers across India. Suboptimal imaging lead to exclusion of 48 radiographs. Crossover sign, ischial spine sign, and posterior wall sign were included in “acetabular rotation abnormalities (R),” lateral center-edge angle and acetabular index were included in “acetabular overcoverage abnormalities (O)” while pistol grip deformity and alpha angle in “femoral abnormalities (F).” Furthermore, all the hips were divided into 4 types: normal hips (N); type I hip with single abnormality (R/O/F); type II with combination of any 2 (RO/RF/OF), and type III with all 3 abnormalities. ResultsSixty-eight percent of 904 hips had at least 1 type of abnormality with 47.5% hips having signs of pincer impingement, 7.9% with signs of cam impingement, and 10.8% with mixed signs. Type I.R hips (32%) were the most common hips followed by type I.O hips (18%) and type I.F (8%). Males had higher percentage of abnormalities (1.5 times) compared to females. Interobserver reliability was 0.55 to 0.81 for all the parameters. Power of study was 0.98. ConclusionRadiographic morphology of FAI exists with high prevalence in young asymptomatic Indian population similar to other ethnicities except for low prevalence of cam morphology. Long-term follow-up of this cohort will reveal the natural history of these morphologies.

Computer-Assisted Optimization of the Acetabular Rotation in Periacetabular Osteotomy Using Patient's Anatomy-Specific Finite Element Analysis.

Periacetabular osteotomy (PAO) is a complex surgical procedure to restore acetabular coverage in the dysplastic hip, and the amount of acetabular rotation during PAO plays a key role. Using computational simulations, this study assessed the optimal direction and amount of the acetabular rotation in three dimensions for a patient undergoing PAO. Anatomy-specific finite element (FE) models of the hip were constructed based on clinical CT images. The calculated acetabular rotation during PAO were 9.7°, 18°, and 4.3° in sagittal, coronal, and transverse planes, respectively. Based on the actual acetabular rotations, twelve postoperative FE models were generated. An optimal position was found by gradually varying the amount of the acetabular rotations in each anatomical plane. The coronal plane was found to be the principal rotational plane, which showed the strongest effects on joint contact pressure compared to other planes. It is suggested that rotation in the coronal plane of the osteotomized acetabulum is one of the primary surgical parameters to achieve the optimal clinical outcome for a given patient.

Effectiveness of acetabular revision using a metal reconstruction cage

To explore the clinical outcomes of acetabular revision using a metal reconstruction cage. Between October 2006 and October 2013, 16 patients (16 hips) underwent acetabular revision with a metal reconstruction cage. There were 4 males and 12 females, with the mean age of 62.7 years (range, 49-78 years). The time from total hip arthroplasty to revision was 3-15 years (mean, 8.2 years). The causes for revision were aseptic acetabular loosening in 15 cases, and femoral periprosthetic fracture (Vancouver type B3) in 1 case. According to the American Academy of Orthopaedic Surgeons (AAOS) classification, there were 12 cases of type III and 4 cases of type IV; according to the Paprosky classification, there were 12 cases of type IIIA and 4 cases of type IIIB. Harris score was used for hip function evaluation, and visual analogue scale (VAS) for pain in the thigh. X-ray films were taken for imaging evaluation. Healing of incision by first intention was obtained in all patients. Deep venous thrombosis occurred in 1 patient, and was cured after anticoagulation therapy. No complications of infection, neurovascular injury, and prosthetic dislocation were found. Sixteen patients were followed up 6.8 years on average (range, 2-9 years). The Harris score was significantly increased from preoperative 42.44±4.66 to 91.88±3.28 at last follow-up ( t=-106.30, P=0.00). Two patients had mild pain in the thigh, but pain disappeared at 1 year after operation. At immediate after operation, the abduction angle was 37-54° (mean, 42.9°). The distance between acetabular rotation centre and teardrop line was (33.67±12.19) mm for preoperative value and was (20.67±9.63) mm for postoperative value, showing significant difference ( t=-9.60, P=0.00). The distance between acetabular rotation centre and lateral teardrop was (34.98±12.30) mm for preoperative value and was (40.04±6.61) mm for postoperative value, showing significant difference ( t=-3.15, P=0.00). X-ray film results showed bony fusion at the osteotomy sites at 4 to 12 months after operation. No continuous radiolucent line, prosthetic dislocation, or osteolysis was found, and bony ingrowth was observed in all patients. No patient received re-revision due to prosthetic loosening. The metal reconstruction cage for acetabular revision can achieve good effectiveness for patients with serious bone defect.

Application of 3D reconstruction navigation template in Bernese periacetabular osteotomy

Objective To explore the feasibility of using a navigation template designed based on CT 3D reconstruction in Bernese periacetabular osteotomy (PAO). Methods The 3D print navigation template technology was introduced in the Bernese periacetabular osteotomy for 26 patients (26 hips) with acetabular dysplasia from July 2013 to March 2015. They were 10 males and 16 females, 12 to 32 years of age (average, 18.6 years). There were 14 right hips and 12 left ones. Preoperative patients were prepared by pelvic plain film, CT scan, CT data reconstruction and simulated acetabular osteotomy and rotation in Mimics10.1 software. According to preoperative planning, reverse engineering technology was applied to extract the pelvic anatomic morphology and the osteotomy surface of operative field. Navigation templates were designed and manufactured by 3D printing technology. In operation, the navigation template was attached onto the exposed pelvis and osteotomy surface with complete accurate rotation displacement of osteotomy and acetabular bone block. Lateral center-edge (LCE) angle, acetabular index (AC), extrusion index (EI) and femoral coverage were analyzed. Results The operation time for this group ranged from 2.7 to 4.6 hours, averaging 3.2 hours. Intraoperative bleeding ranged from 950 mL to 3,300 mL, averaging 1,630 mL. No injury to the femoral nerve or sciatic nerve was observed in this group. No serious complications like bone fragments into the hip joint occurred. Postoperative infection was not found in all the cases. Posterior column breakage occurred in only one case. There were significant differences between the preoperative and postoperative measurements regarding LCE, AC, EI and femoral coverage (P 0.05). Conclusion Since application of the navigation template designed based on CT 3D reconstruction in PAO can improve the surgical accuracy and safety, it is an effective method to solve the difficulties of PAO. Key words: Hip dysplasia; Osteotomy; Computer-aided design; 3D reconstruction; Navigation template

Cementless total hip arthroplasty for secondary traumatic hip arthritis after acetabular fracture fixation

Objective To retrospectively analyze short-term outcomes of cementless total hip arthroplasty (THA) in the treatment of secondary traumatic hip arthritis following internal fixation of acetabular fractures in adults. Methods From September 2009 to December 2013, 28 patients were treated with cementless THA for secondary traumatic hip arthritis following internal fixation of acetabular fracture. They were 19 males and 9 females, aged from 23 to 58 years (average, 45.7 years). After surgical debridement and removal of metal implants, all patients underwent intraoperative pathologic analysis of frozen sections. Twenty cases whose neutrophilic granulocyte count ≤ 10 in a high power field received THA at one stage while 8 underwent an antibiotic-loaded cement spacer at the first stage and THA at the second stage when their values of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) became normal. Harris scores were used to evaluate function of the hip. Results All the patients were followed up for an average of 28.5 months (range, from 15 to 58 months). The Harris hip score improved significantly from 52.7±4.7 preoperatively to 93.7±5.7 at the final follow-up (t = 32.341, P= 0.000). No prosthetic dislocation, loosening or periprosthetic osteolysis was found at the last follow-up. By the Engh criteria, bony fusion was achieved at the interface of prosthesis-bone, positions of the acetabular cups were stably fine, and no change occurred in acetabular rotation. No reinfection or periprosthetic fracture occurred after THA. Conclusions THA is an effective salvage procedure for severe posttraumatic hip arthritis following internal fixation of acetabular fracture. Intraoperative pathologic analysis of frozen sections is necessary to judge hip infection. Releasing contracted hip soft tissue, removing metal implants, reconstructing acetabular bone defects and implanting Tantalum monoblock acetabular cup with a high frictional coefficient are essential to good outcomes of THA. Key words: Acetabulum; Fractures, bone; Osteoarthritis, hip; Arthroplasty, replacement, hip

Diagnose und Therapie der Hüftdysplasie des älteren Kindes

Diagnosis of congenital hip dysplasia is based on normal values of the acetabulum, but also criteria such as deficiency of the acetabular rim and an increased distance from the tear drop figure. Instability of the hip joint is seen in arthography. Acetabuloplasty is the way to treat it. Unstable joints will deteriorate, stable ones are frequently improving spontaneously. The technique of open reduction from an inguinal approach medial of the psoas muscle is described. There are many advantages. Simultaneous shortening osteotomy and acetabuloplasty to permit immediate movements out of the hip spica are recommended to avoid stiffening and contractures. Hip dysplasia is corrected by a lateral acetabuloplasty that levers down the acetabular roof in the triradiate cartilage. After consolidation of the cartilage triple pelvic osteotomy for acetabular rotation is the method to correct dysplasia in adolescents and adults. The closer the osteotomies are performed to the hip joint, the better rotation is possible. Our technique has proved successful now in 12 years.

Three-dimensional computed tomography analysis and anteversion study after periacetabular osteotomy of pelvis in children

Three-dimensional computed tomography (CT) is the method of choice in understanding the morphological changes after periacetabular osteotomy in children. We studied different parameters and compared aspects of operated hip (OH) with non-operated hip (NOH) to define the maneuver that promotes normalization of the hip during repositioning of the acetabulum. A total of 22 patients with 25 OHs underwent CT control scans an average of 4 years after surgery. The patients, with a mean age of 6.8 years, had either Legg-Calvé-Perthes disease (12 cases) or dysplasia (10 cases).The measurements included the anterior and posterior coverage angles of the hip and version of the acetabulum on axial CT views. The 3D reconstructed images measured the inclination of the antero- and postero-lateral lips, the external rotation and the anterior inclination of the acetabulum. The mean anterior coverage angle was 27 degrees for OHs, 31 degrees for NOHs, and 12 degrees versus 10.3 degrees for the posterior coverage angle. Acetabular anteversion was 2 degrees for OHs (6.3 degrees in the dysplastic OHs) and 6 degrees for NOHs. The mean angle of inclination of the antero-lateral lip was 37 degrees for OHs, 47 degrees for NOHs, and the postero-lateral lip inclination was 56 degrees for OHs and 67 degrees for NOHs. Inferior 3D views showed a mean internal acetabular rotation of 1.5 degrees (4.8 degrees in the dysplastic OH), 3 degrees for NOH. The anterior acetabular inclination angle measured with lateral 3D views was 6 degrees for OHs, 11 degrees for NOHs. Our analysis demonstrated a mean anteversion of the acetabulum despite normalization of the anterior coverage of the hip, particularly in the dysplastic group, in which the osteotomized fragments had anteversion superior to NOH. The unexpected external rotation used to improve anterior coverage of a coax magna in Legg-Calvé-Perthes disease was responsible for the retroversion and the decrease of the posterior coverage.

Lateral Acetabular Rotation Improves Anterior Hip Subluxation

Surgical reorientation of the acetabulum is used to improve stability of subluxated or dysplastic hips, but the specific mechanical consequences of reorientation have not been quantified. I used a rigid body spring model of the human hip to study the effects of different acetabular positions on hip stability during single-limb stance. The model predicted subluxation direction and magnitude, and the effective joint contact area, as functions of acetabular position. Frontal plane acetabular orientation varied from 20 degrees medial rotation to 50 degrees lateral rotation, corresponding to center-edge angles from 0 degrees to 70 degrees. Sagittal acetabular orientation varied from 45 degrees anterior rotation to 15 degrees posterior rotation. Center-edge angles less than 20 degrees produced progressive anterolateral subluxation, with dislocation occurring when center-edge angles were less than 0 degrees. Lateral subluxation disappeared when cen-ter-edge angles were 30 degrees or greater. Anteroposterior subluxation was controlled by anterior or posterior rotation of the acetabulum in the presence of low center-edge angles, but there was no specific position of stability that effectively stabilized the femoral head. Anterior subluxation also was controlled by lateral rotation of the acetabulum. Joint contact area increased 1% for every 3 degrees lateral acetabular rotation. The anterolateral subluxation associated with hip dysplasia can be controlled by acetabular reorientation. Joint contact area will increase, thereby reducing peak joint pressure. Anterior and lateral subluxation can be improved by lateral rotation alone, which may reduce the severity of anterior femoroacetabular impingement after periacetabular osteotomy.