Automatic measurement of polyethylene modification in metal-backed artificial hip joints using three-dimensional CT

A new method has been developed for automatic measurement of polyethylene linear modification using three-dimensional CT in total hip arthroplasty (THA) and bipolar hemiarthroplasty (BHP). We obtained a three-dimensional digital image of the metal components by widening the maximum window width, adjusting the proper cutoff threshold level, and removing the metal artifact. The centric coordinates of both the metal-backed cup and the femoral head were calculated from this image. Modification was defined as a change in distance between those two points from their original interval. Phantom studies of the accuracy and reproducibility of the method indicated that the average error ranged from 0.02 to 0.12mm and the standard deviation ranged from 0.01 to 0.05mm. Clinical in vivo measurement was performed without error of computer software on 19 hips in which modification of highly cross-linked polyethylene components was significantly large.     

Evaluation of acetabular dysplasia using a top view of the hip on three-dimensional CT

We assessed coverage over the femoral head, using three-dimensional computed tomography (CT) imaging on 20 hips in 18 patients before rotational acetabular osteotomy, and on 18 normal hips as control. In particular, we introduced a "top view of the hip" in three-dimensional CT evaluation in order to detect posterolateral deficiency, which needs special attention in regard to rotational transfer of the acetabular fragment. We determined the horizontal plane passing through 5 mm cranial to the top of the femoral head on the coronal view of a multiplanar reconstruction image. Then, we erased the images of the ilium that were more cranial than this horizontal plane from the conventional cranial view of the pelvis and the proximal femur, and defined this view as the "top view of the hip". This top view clearly showed any uncovered area on the femoral head. Of the 20 hips, 6 were deficient anterolaterally (anterolateral type), 9 were deficient laterally (lateral type), and 5 were deficient posterolaterally (posterolateral type). On plain anteroposterior radiographs, 7 of the 20 hips had the cross-over sign of Reynolds. Five of these 7 hips with the cross-over sign were the posterolateral type in top view, while none of the 13 hips without the cross-over sign was the posterolateral type. We recommend preoperative evaluation using a top-view on three-dimensional CT images in patients who have the cross-over sign on an anteroposterior radiograph. Received: December 16, 1999 / Accepted: June 28, 2000     

Assessment of the talar deformity and alignment in congenital clubfoot using three-dimensional MRI after Ponseti method

BackgroundPonseti method have been widely accepted as the initial treatment of congenital idiopathic clubfoot because its excellent primary result. On the other hand, relapses after Ponseti method are not uncommon and the cause of relapses have not been fully elucidated. We investigated detailed morphology and alignment of tarsal bones in clubfoot after Ponseti method using three-dimensional MRI analysis.MethodsWe performed MRI with 10 patients of unilateral clubfoot at three months after Achilles tenotomy. Based on the MRI volume data, we reconstructed three-dimensional bone surface model using the marching cubes method. We evaluated the volume of the talus and navicular bone, medial and planter deviation of the talar head and neck, medial deviation of the navicular bone, and internal rotation angle of the distal tibiofibular joint.ResultsIn clubfoot, the volume of talus and navicular bone were significantly smaller compared with the contralateral side. Deviation of the talar head and neck varied from medially to almost the same as that on the contralateral side. The degree of deformity of the talus and alignment of the navicular bone and distal tibiofibular joint showed correlations.ConclusionsPatients with the medial deviated talar neck might have the alignment change of navicular bone and distal tibiofibular joint. Deformity of talar neck might to be compensated by talonavicular joint and distal tibiofibular joint through the manipulation of Ponseti method.     

术前三维CT理想钉道测量辅助置入经皮骶髂螺钉

目的探讨术前三维CT理想钉道测量在经皮骶髂螺钉置入中的临床价值。方法 15例骨盆后环损伤行CT三维重建后,在三维图像上设计骶髂螺钉的理想钉道(进钉点为髂前上棘与髂后上棘连线的中后1/3处,通过S1椎弓根中轴线)。在出口位及入口位上,测量理想钉道的进钉角度(∠A、∠B)。术中C臂机射线投照方向与术前三维图像测量时的位置保持一致,参照所测角度置入克氏针,并测量术中C臂机图像上克氏针进针角度(∠a、∠b),然后置入螺钉。按Mears复位标准评价骨折复位情况;根据CT图像判断螺钉的穿透情况;采用Majeed功能评分进行临床评价。结果 15例患者术前在三维图像的骨盆出口位及入口位上理想钉道进钉角度(∠A、∠B)分别为1°~19°(7.9°±5.8°)、1°~9°(5.6°±2.8°),术中在C臂机透视下骨盆出口位及入口位上测量克氏针进钉角度(∠a、∠b)分别为1°~21°(8.4°±4.9°)、1°~15°(6.9°±4.5°),两者间差异无统计学意义(P0.05)。共置入18枚螺钉。15例均获随防,时间5~35(14.2±5.1)个月。无医源性血管、神经损伤,无螺钉断裂发生。Mears标准评价骨折复位情况:解剖复位8例,满意复位7例。根据CT图像判断螺钉的穿透情况:0级16枚,1级2枚,无2、3级穿透。Majeed功能评分:优10例,良4例,可1例。结论通过三维CT测量获得理想钉道在出口及入口位上的进钉角度,结合术中C臂机透视个体化进钉能够保证经皮置入骶髂螺钉的准确性。     

Assessment of hindfoot deformity by three-dimensional MRI in infant club foot

In 12 infants aged under 16 months with unilateral club foot we used MRI in association with multiplanar reconstruction to calculate the volume and principal axes of inertia of the bone and cartilaginous structures of the hindfoot. The volume of these structures in the club foot is about 20% smaller than that in the normal foot. The reduction in volume of the ossification centre of the talus (40%) is greater than that of the calcaneus (20%). The long axes of both the ossification centre and the cartilaginous anlage of the calcaneus are identical in normal and club feet. The long axis of the osseous nucleus of the talus of normal and club feet is medially rotated relative to the cartilaginous anlage, but the angle is greater in club feet (10 degrees v 14 degrees). The cartilaginous structure of the calcaneus is significantly medially rotated in club feet (15 degrees) relative to the bimalleolar axis. The cartilaginous anlage of the talus is medially rotated in both normal and club feet, but with a smaller angle for club feet (28 degrees v 38 degrees). This objective technique of measurement of the deformity may be of value preoperatively.     

三维CT重建对先天性髋关节脱位的临床价值

目的探讨三维CT重建在先天性髋关节脱位(CDH)的临床应用.方法本组CDH患儿22例,其中双髋脱位15例,单髋脱位7例,另有正常髋2例,共计患髋37个,正常对照髋11个.采用Picker公司PQ6000螺旋CT机,在独立工作站进行表面遮盖成像(SSD)、最大密度投影(MIP)、多平面重建(MPR)和相关数据测量.结果分别对股骨头颈、髋臼及头臼关系行三维直观显示,运用MPR技术测量了髋臼指数(AI)和股骨颈前倾角(FNA).结论三维CT可以直观、全面及分解地显示髋关节结构,对于股骨头、髋臼形态和头臼关系的显示具有常规X线和普通CT平扫所无法比拟的优越性,加之更加精确的测量,大大提高了术前诊断的科学性和手术的预见性,为手术方案的制定提供了新的客观依据.     

三维CT重建在肩胛骨骨折中的应用

目的 探讨三维CT重建在肩胛骨骨折治疗中的指导意义。方法 7例肩胛骨粉碎性骨折患者接受x线、CT扫描、三维CT重建检查，对骨折的严重程度进行评估，并据此制定最佳治疗方案。结果 7例中，4例累及肩胛颈，2例累及肩胛颈和肩胛盂，1例伴锁骨骨折；6例接受手术治疗。所有患者均获得随访，随访时间3个月-2年6个月，骨折平均愈合时间7-10周，肩关节功能恢复良好。结论 三维CT重建能多方位、立体、全面地显示肩胛骨骨折部位、程度。对骨折手术方案的制定、手术人路和内固定的选择有很强的指导意义。     

CT image analysis for surface reconstruction of the hip joint

From a sequence of planar CT-pictures of the hip joint the diagnostically relevant contours are extracted on a graphic monitor by means of an image analysis process. To enable this an image-preprocessing has been needed to improve quality of the CT-pictures. From theses contour data, a mathematical surface model of the hip joint will be derived with well-known methods to simulate osteotomy.     

Measurement of hip prostheses using image analysis. The maxima hip technique

A computer-based image analysis system has been developed as a research tool in total hip replacement. The system has been programmed to take multiple measurements from coronal plane radiographs. Poor quality radiographic images can be enhanced and standardised. The measurements which can be obtained include stem subsidence, cup migration, cup wear, and stem loosening. Reproducibility and accuracy were +/- 0.01 mm and +/- 0.5 mm respectively. The present application is in retrospective research, but prospective monitoring of radiographs is planned.     

三江地区成人颧骨复合体三维X线头影测量与三维CT测量的比较

目的 探讨颧骨复合体三维X线头影测量与三维CT测量的比较研究.方法 从佳木斯大学在校学生中挑选120名汉族女大学生（出生并生长于三江地区）,年龄19～23岁（平均21.4岁）.采用三维X线头影测量技术和三维CT测量技术,对其面部和颅骨组织做定量测量研究,测量标记点参照祁佐良颧骨颧弓大小的测量方法,测量上面宽、中面宽、下面宽、颧突宽、颧突距和颧突角,并计算骨性面型宽度比值,对以上两种测量结果进行统计学分析.结果 三维CT测量面型宽度比值分别为0.83和0.79,骨性面型宽度比值分别为0.81和0.77;三维X线头影测量面型宽度比值分别为0.84和0.80,骨性面型宽度比值分别为0.82和0.77.两种方法的测量结果差异无统计学意义（P＞0.05）.结论 三维CT测量与三维X线头影测量,均可以应用于颧骨复合体肥大的诊断.     

Assessment of midcarpal deformity of the wrist using the triangulation method

PURPOSE: The purpose of this study is to present an alternative method for static radiologic assessment of the wrist for midcarpal instability (ie, palmar intercalated segmental instability [PISI] and dorsal intercalated segmental instability [DISI]). The triangulation method uses 3 anatomic landmarks observed on the standard lateral x-ray of the wrist. METHODS: A total of 125 normal lateral radiographs were measured to determine the normal range for the dorsal limb (DL) to palmar limb (PL) ratio. A 2-step process of performing triangulation is described. The first step is nonspecific screening of the radiograph and defines values greater than 1.0 as having a DISI deformity and values less than 0.5 as having a PISI deformity. The second step is used only for borderline values, which takes the position of the wrist into consideration and uses a normagram (reference chart) to match the DL:PL ratio with the radiometacarpal (RM) angle. RESULTS: The average lateral wrist position was 8.4 degrees of extension (-8.4). The average DL:PL ratio was 0.75 +/- 0.09 (range, 0.93-0.57). CONCLUSIONS: Based on these data we defined DISI deformity of the wrist as DL:PL ratios greater than 1.0, and ratios less than 0.5 representing PISI deformities. The triangulation method of assessing midcarpal alignment of the carpus is a practical and simple alternative to the traditional static radiologic method of assessing midcarpal instability of the wrist.     

Limb lengthening and three-dimensional deformity corrections

Summary Different methods of limb lengthening as used at the Orthopedic Surgery Clinic of the Medical School, University of Zagreb, are compared. The results of operations performed between 1979 and 1989 on 111 patients are presented. These patients were subjected to surgery aimed at length equalization of limbs and/or correction of three-dimensional deformities. Lengthening was performed in 104 patients at one level, and in 7 patients at two levels of the same limb for a total of 118 procedures. In order to compare limb lengthening techniques the patients were divided into four groups: group I, original Wagner technique (45 patients); group II, Wagner technique using corticotomy (33 patients); group III, original Ilizarov technique (35 patients); group IV, continuous lengthening (2 patients). The evaluation covered radiological aspects of regenerated bone, complications and basic lengthening parameters. The results indicate that corticotomy has considerable advantages over osteotomy, provided bone circulation is maintained. These advantages manifest themselves in a reduced number of operations, lower incidence of infection and improved bone regeneration. It is preferable to perform corticotomy at the metaphysis site because of its optimum blood supply and its higher potential for osteogenesis. With corticotomy performed at the diaphysis site, satisfactory results were observed in only one-third of the cases.     

Application of three-dimensional image reconstruction technology based on high-resolution CT in pyeloplasty

BackgroundThree-dimensional (3D) image reconstruction technology is widely used in surgical operations for its intuitive visualization. Pyeloplasty requiresprecise cutting and suturing. The reconstruction technology can accurately determine the location and scope of the stenosis at the junction of the renal pelvis and ureter and the relationship with the surrounding vasculature. The purpose of this article is to retrospective evaluate the application value of image reconstruction technology in pyeloplasty based on high-resolution 3D CT images.MethodsA total of 20 patients with renal pelvic ureteral junction obstruction admitted to our hospital from August 2019 to August 2020 were selected. In this group, left pyeloplasty was performed in 8 patients and right pyeloplasty in 12 patients. In terms of conditions, there was 1 case with secondary pyeloplasty, 6 cases of patients with kidney stones, 2 cases with renal ectopic blood vessels, 1 case with renal prolapse, 1 case with horseshoe kidney, and 1 case with ureteral polyps. There were 12 males and 8 females, with an average age of 34.65±10.67 years and an average body mass index (BMI) of 22.48±3.03 kg/m². In all patients, 3D CT reconstruction technology was used to guide the formulation of robot-assisted laparoscopic pyeloplasty plans; verify the consistency between the actual operation and the preoperative planning; and observe the operation time, blood loss, postoperative exhaust time, indwelling drainage tube time, and follow-up for comorbidities.ResultsThe operation was successful in all 20 patients. The actual operation was 100% consistent with the preoperative planning, the operative time was 160.80±63.26 min, the intraoperative blood loss was 47±30.45 mL, the postoperative exhaust time was 1.15±0.37 days, the drainage tube indwelling time was 4.35±1.50 days, and the average follow-up time was 7.95±3.41 months. There were no complications.ConclusionsThree-dimensional image reconstruction technology based on high-resolution CT has high clinical application value in the treatment of ureteropelvic junction obstruction (UPJO), which simplifies the operation process and shortens the operation time, and is a valuable tool for auxiliary surgeons in devising the operation plan.     

CT三维重建在尺骨冠状突骨折中的应用

目的探讨CT三维重建在尺骨冠状突骨折治疗中的指导意义。方法对19例尺骨冠状突骨折患者摄X线片、CT扫描及CT三维重建检查,对骨折进行分型,并据此制定最佳治疗方案。结果根据尺骨冠状突骨折的O’Drlscoll分型,CT三维重建图像显示19例尺骨冠状突骨折患者中Ⅰ型骨折6例,Ⅱ型骨折11例,Ⅲ型骨折2例。除2例Ⅰ型冠状突骨折外,余17例均采用了内固定治疗。19例均获得随访,时间6～30个月。骨折均愈合,愈合时间8～12周。疗效根据Morrey et al的肘关节功能诊断标准评定:优12例,良4例,差3例。结论 CT三维重建能多方位、立体、全面地显示冠状突骨折情况,对骨折分型、治疗方案选择有很强的指导意义。     

Assessment of incident spine and hip fractures in women and men using finite element analysis of CT scans

Finite element analysis of computed tomography (CT) scans provides noninvasive estimates of bone strength at the spine and hip. To further validate such estimates clinically, we performed a 5‐year case‐control study of 1110 women and men over age 65 years from the AGES‐Reykjavik cohort (case = incident spine or hip fracture; control = no incident spine or hip fracture). From the baseline CT scans, we measured femoral and vertebral strength, as well as bone mineral density (BMD) at the hip (areal BMD only) and lumbar spine (trabecular volumetric BMD only). We found that for incident radiographically confirmed spine fractures (n = 167), the age‐adjusted odds ratio for vertebral strength was significant for women (2.8, 95% confidence interval [CI] 1.8 to 4.3) and men (2.2, 95% CI 1.5 to 3.2) and for men remained significant (p = 0.01) independent of vertebral trabecular volumetric BMD. For incident hip fractures (n = 171), the age‐adjusted odds ratio for femoral strength was significant for women (4.2, 95% CI 2.6 to 6.9) and men (3.5, 95% CI 2.3 to 5.3) and remained significant after adjusting for femoral neck areal BMD in women and for total hip areal BMD in both sexes; fracture classification improved for women by combining femoral strength with femoral neck areal BMD (p = 0.002). For both sexes, the probabilities of spine and hip fractures were similarly high at the BMD‐based interventional thresholds for osteoporosis and at corresponding preestablished thresholds for “fragile bone strength” (spine: women ≤ 4500 N, men ≤ 6500 N; hip: women ≤ 3000 N, men ≤ 3500 N). Because it is well established that individuals over age 65 years who have osteoporosis at the hip or spine by BMD criteria should be considered at high risk of fracture, these results indicate that individuals who have fragile bone strength at the hip or spine should also be considered at high risk of fracture. © 2014 American Society for Bone and Mineral Research.     

Virtual Bernese osteotomy using three-dimensional computed tomography in hip dysplasia

Background  

Accurate assessment of acetabular morphology and its relationship to the femoral head is essential for planning a periacetabular osteotomy. We observed the acetabular coverage after virtual Bernese osteotomy using computer-aided technique.     

严重髋关节融合强直畸形的全髋关节置换术

目的探讨采用全髋关节置换术(THA)治疗严重髋关节融合强直畸形的手术方法及临床疗效。方法对48例(57髋)严重髋关节融合强直畸形分次行单侧THA,均采用外侧切口,通过对股骨颈2次截骨后,根据骨盆倾向头侧还是尾侧进行髋臼成形,正确定位臼杯的外展角,根据患侧屈曲畸形情况进行股骨柄和髋臼前倾角的调整。结果术后48例均获随访平均28.5(12~36)个月,1例一侧假体下沉4 mm,1例出现假体周围骨折,1例出现股骨近端劈裂,1例出现坐骨神经的牵拉伤。末次随访时,Harris评分从术前平均16.3分提高到85.6分;髋关节活动度由术前0°提高至术后平均152.5°,其中平均屈髋91.4°;髋关节屈曲畸形程度由术前平均25.6°改善至术后平均5.1°。术后患者髋痛基本消失,术侧步态基本恢复正常,无严重并发症发生。结论严重髋关节融合强直屈髋畸形的THA不能按常规的方式处理,显露出真臼底和根据术前患肢的内旋或外旋程度把握好准确的前倾角、外展角是手术成功的关键。     

Evaluation of the urinary bladder using three-dimensional CT cinematic rendering

Three-dimensional (3D) visualizations of volumetric data from computed tomography (CT) acquisitions can be important adjuncts to interpretation of two-dimensional (2D) reconstructions. Recently, the 3D technique known as cinematic rendering (CR) was introduced, allowing photorealistic images to be created from standard CT acquisitions. CR methodology is under increasing investigation for use in the display of regions of complex anatomy and as a tool for education and preoperative planning. In this article, we will illustrate the potential utility of CR for evaluating the urinary bladder and associated pathology. The urinary bladder is susceptible to a multitude of neoplastic and inflammatory conditions and their sequelae. The intrinsic properties of CR may prove useful for the display of subtle mucosal/luminal irregularities, the simultaneous display of soft tissue detail with high-resolution maps of associated tumor neovasculature, and the improved display of spatial relationships to aid pre-procedural planning. Further refinement of presets for CR image creation and prospective evaluation of urinary bladder CR in real-world settings will be important for widespread clinical adoption.