The combined anteversion technique for acetabular component anteversion

The combined anteversion technique for acetabular component placement of total hip arthroplasty is beneficial because of the surgeons' limited ability to control the anteversion of a cementless femoral stem. Our data show that the cementless stem anteversion can be 15 degrees different than anticipated. By determining femoral stem anteversion before positioning cup anteversion, the cup anteversion can be adjusted for the stem anteversion. The combined anteversion technique should provide a mean near 35 degrees with a safe zone of 25 degrees to 50 degrees.     

CT-based navigation systems for intraoperative radiotherapy using the afterloading-flab technique.

INTRODUCTION: The fact that conventional intraoperative radiotherapy does not give the opportunity to exactly document the radiation volume applied and the dose distribution has been criticized in many ways. We would like to introduce a system for surgical navigation and documentation of flap positioning in intraoperative brachytherapy using the afterloading flap technique. METHODS: Our system consists of an electromagnetic 3D-digitizer and a PC workstation. Spiral CT scans of the tumor region taken preoperatively are used for navigation and documentation of flap positioning, analogous to the procedure in neuronavigation. Registration is done via an external reference system which is attached to the iliac bone of the patient. RESULTS: The mean accuracy of digitalization of the 100 spheres in a pelvis model is about 2.6 +/- 0.5 to 3.7 +/- 9.9 mm. The mean navigation accuracy is 2.4 +/- 0.8 to 3.3 +/- 0.8 mm. These figures correspond to the clinical experience of our surgeons. DISCUSSION: The optimization of flab positioning by CT-guided navigation and the more accurate documentation of the dose volume and distribution in the patient is an important step on the way to improving the quality of individual radiation therapy. We are of the opinion that surgical navigation in the pelvic region should be subject to additional investigation in order to optimize the procedure.     

Achievement of optimal implant alignment using taper wedge stems with cup-first THA through the MIS antero-lateral approach

European Journal of Orthopaedic Surgery & Traumatology - Combined anteversion (CA) technique (stem-first procedure) has become generally accepted as an ideal means to achieve optimal CA value...     

X线透视与计算机导航系统引导颈椎椎弓根螺钉内固定技术的对比研究

目的对X线透视下和计算机导航系统引导下颈椎椎弓根螺钉内固定的精确性进行对比研究。方法X线透视引导下145枚和CT三维导航系统辅助下置入的159枚颈椎椎弓根螺钉,术后进行经椎弓根螺钉水平的CT平扫或术后c型臂透视3D重建,观察椎弓根螺钉置入的精确性。结果X线透视引导组螺钉置入满意率为91．7％,CT三维导航系统引导组螺钉置入满意率为97．5％,两组满意率有显著性差异（P〈0．05）。两组病例均未出现明显的神经血管损伤并发症。对其中20例病例进行了术中导航操作时间和导航精确性的监测,术中工具注册和参考点照合时间平均3．5min（2～8min）,位置误差率平均0．31mm（0．12～0．56mm）。每颗椎弓根螺钉定位针置入所需时间平均2min（1-3．5min）。术中只需进行两次C型臂透视印证螺钉定位针和螺钉置入的准确性。结论采用CT三维导航系统辅助,能显著提高椎弓根螺钉置入的精确性。     

Femoral neck anteversion, acetabular anteversion and combined anteversion in the normal Indian adult population: A computed tomographic study

Background:

Abnormal femoral neck anteversion (FNA) and/or acetabulum anteversion (AA) have long been implicated in the etiogenesis of hip osteoarthritis (OA), developmental dysplasia of the hip (DDH), and impingement, instability and wear in total hip arthroplasty (THA). Since studies on the Indian population are sparse on this topic, the purpose of this study was to report the normal values of FNA, AA and the combined anteversion (CA= FNA+ AA) in Indian adults.

Materials and Methods:

FNA, AA and CA were prospectively measured in 172 normal hips in 86 Indian adults using standardized computed tomographic (CT) methods and this data was compared with the established Western values.

Results:

The median values and interquartile ranges were 8° (6.5-10.0°) for FNA, 19° (16.0-22.0°) for AA and 27° (23.5-30.0°) for CA. AA and CA values were significantly (P<0.05) lower in males, and there was also a trend towards lower FNA in males. Although a negative correlation was observed between the FNA and AA, this was not strong and may not be clinically relevant.

Conclusion:

When compared with the Western data, the FNA values were 3-12° lower and the CA values were 3-5° lower in Indian adults. The AA values were comparable, but were skewed towards the higher side. Further studies are needed to assess the clinical relevance of our basic science data in pathogenesis of OA, and to validate it in relation to hip surgeries like corrective osteotomies and THA.     

Novel measurement method on plain radiographs to predict postoperative stem anteversion in cementless THA

Preoperative knowledge of femoral stem anteversion can reduce instability and impingement especially using the standard “cup first” technique in cementless total hip arthroplasty (THA). In this study, we asked whether stems at risk of retroversion or high anteversion (>20°) can be detected preoperatively using hip radiographs in two planes (anteroposterior and Lauenstein). In 123 patients undergoing cementless THA using a non‐anatomic, non‐modular, straight stem, low centered hip radiographs in two planes were obtained preoperatively and three‐dimensional computed tomography (3D‐CT) 6 week postoperatively. The novel developed Isthmus Ratio (iRatio) as the relation between canal isthmus and calcar isthmus in the anteroposterior and Lauenstein view was calculated by two observers twice in a 6‐week interval. iRatio was compared to postoperative 3D‐CT stem version measured by an independent and blinded, external institute. We found a correlation between mean radiographic iRatio and 3D‐CT stem torsion of r = 0.578 (p < 0.0001). The observers had excellent agreements within (ICC ≥0.918) and between (mean CCC = 0.967) radiographic iRatio measurements. Eighty‐one percent (21/26) of the retroverted cementless stems had a preoperative iRatio below 0.35 and 91% (10/11) of stems with an anteversion exceeding 20° an iRatio above 0.55, respectively. The novel iRatio represents a feasible and reliable method for analyzing anteversion of the final stem on plain radiographs before cementless THA with a straight, tapered stem. iRatios below 0.35 and above 0.55 represent a warning of retroversion and anteversion more than 20° of the final stem, respectively. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2025–2030, 2016.     

Navigation in total-knee arthroplasty: CT-based implantation compared with the conventional technique

Background Exact axial limb alignment in total-knee arthroplasty (TKA) is important for a successful outcome. We evaluated the efficiency of computer-assisted implantation in TKA and compared it with the classical surgeon-controlled technique. Patients and methods We implanted 100 TKA using either the computer-assisted technique (50) or the conventional approach (50). There were no significant differences between the groups regarding the preoperative leg deformity. Accuracy of implantation was determined in postoperative long-leg coronal and lateral radiographs. Results A postoperative leg axis between 3 degrees varus and 3 degrees valgus was achieved in 46 patients in the group with computer-assisted implantation and 36 patients in the control group (p=0.01). A significant difference was also seen for the femoral component alignment in frontal plane. No complications influencing the clinical outcome were observed. Interpretation A CT-based navigation system improves the accuracy of TKA, but higher costs and time-consuming planning will mean that its usage is limited to special cases. Additional tools such as ligament balancing, which are presently only available with the CT-free software module, require to be added to the CT-based system.     

Use of the Cusum technique for evaluation of a CT-based navigation system for total knee replacement

Most of the early failures of total knee replacements are related to technical flaws. Conventional ancillary devices achieve good alignment in the frontal plane in only an average of 75% of total knee replacements. Computer-assisted surgery may improve the technical quality of implantation surgery. The aim of our study was to evaluate the use of computer-assisted surgery using a quality control process. Seventy-eight total knee arthroplasties were done with a CT-based computer-assisted surgery system. The outcomes studied were alignment of the lower limb, implant positioning, and operative time. The target for alignment was 180 degrees +/- 3 degrees. Cusum analysis showed that the three outcomes were controlled during the study. The cusum test identified any existing outliers. Because few data were available at the beginning of this study regarding computer-assisted surgery for total knee replacement, a randomized study was not relevant. However, a control of the procedure was mandatory. The cusum technique allowed continuous evaluation of the performance of the new procedure, and is a useful tool in assessing new technology. The results of this study showed that it is possible to do a randomized study to determine if computer-assisted surgery can improve the technical result of total knee replacement.     

联合前倾角技术在成人发育性髋关节发育不良全髋关节置换术中的应用

目的探讨联合前倾角技术在成人发育性髋关节发育不良全髋关节置换术中应用的可行性及临床价值。方法回顾性分析自2016-09—2018-06采用联合前倾角技术行全髋关节置换术治疗的31例(36髋)成人发育性髋关节发育不良,比较手术前后髋臼前倾角、股骨前倾角、联合前倾角及髋关节功能Harris评分。结果31例均获得12个月以上随访。术后骨盆正位及髋关节侧位X线片显示假体位置及对应关系良好,无假体松动、下沉,无脱位表现。末次随访时所有患者步态均明显改善,髋部疼痛均消失,仅2例轻度跛行。术后髋臼前倾角、股骨前倾角、联合前倾角较术前明显减小,末次随访时髋关节功能Harris评分较术前明显增加,差异有统计学意义(P<0.05)。结论联合前倾角技术应用于成人发育性髋关节发育不良全髋关节置换术对于指导合适假体的选择、设计以及确定合适的髋臼前倾角、股骨柄前倾角具有重要意义,良好的联合前倾角能够有效预防术后假体脱位的发生。     

Navigated femoral anteversion measurements: a new intraoperative technique

AIM: To evaluate and compare the accuracy of using the femoral neck axis and the greater trochanter with navigation to determine femoral anteversion. METHODS: Eight human femora with midshaft fractures were used. Real anteversion (AV) values were first measured on a movable fixation system, with digital images imported to software. Second, a navigation system determined the femoral AV with fluoroscopic images of hip, fracture site and femoral condyles. AV I: the centre of the femoral head to the femoral neck axis, the lateral distal femoral condyles and the distal fragment were marked. AV II: the centre of femoral head to the centre of the greater trochanter was marked by the same method. RESULTS: Actual femoral AV ranged from 1.0 degrees to 9.0 degrees . Head-neck landmarks revealed a mean difference of 1.4 degrees . The greater trochanter-femoral head landmarks revealed a mean difference of 0.3 degrees , significantly less than the head-neck measurements. CONCLUSIONS: Compared with the reliable methods of determining femoral rotation postoperatively, intraoperative measurement is difficult. We found that the centre of the tip of the greater trochanter is easier to identify than the centre of the femoral neck and gives more precise results. This requires analysis of the contralateral limb, which may be feasible with newer non-invasive registration methods.     

The laparoscopic nissen-hill hybrid: pilot study of a combined antireflux procedure

Background

Laparoscopic antireflux surgery is highly effective in patients with uncomplicated gastroesophageal reflux disease (GERD). However, long-term failure rates in paraesophageal hernia (PEH) and Barrett’s metaplasia (BE) are higher and warrant a more durable repair. Outcomes for the laparoscopic Nissen fundoplication (LNF) and Hill repair (LHR) are equivalent, but their anatomic components are different and may complement each other (Aye R Ann Thorac Surg, 2012). We designed and tested the feasibility and safety of an operation that combines the essential components of each repair.

Methods

A prospective, phase II pilot study was performed on patients with symptomatic giant PEH hernias and/or GERD with nondysplastic Barrett’s metaplasia. Pre- and postoperative esophagogastroduodenoscopy (EGD), upper gastrointestinal study (UGI), 48-hour pH testing, manometry, and three quality-of-life metrics were obtained.

Results

Twenty-four patients were enrolled in the study. Three patients did not complete the planned procedure, leaving 21 patients, including 12 with PEH, 7 with BE, and 2 with both. There were no 30-day or in-hospital mortalities. At a median follow-up of 13 (range 6.4–30.2) months, there were no reoperations or clinical recurrences. Two patients required postoperative dilation for dysphagia, with complete resolution. Mean DeMeester scores improved from 54.3 to 7.5 (p < 0.0036). Mean lower esophageal sphincter pressures (LESP) increased from 8.9 to 21.3 mmHg (p < 0.013). Mean short-term and long-term QOLRAD scores improved from 4.09 at baseline to 6.04 and 6.48 (p < 0.0001). Mean short-term and long-term GERD-HQRL scores improved from 22.9 to 7.5 and 6.9 (p < 0.03). Mean long-term Dysphagia Severity Score Index improved from 33.3 to 40.6 (p < 0.064).

Conclusions

The combination of a Nissen plus Hill hybrid reconstruction of the gastroesophageal junction (GEJ) is technically feasible, safe, and not associated with increased side effects. Short-term clinical results in PEH and BE suggest that this may be an effective repair, supporting the value of further study.     

Three dimensional-CT evaluation of femoral neck anteversion, acetabular anteversion and combined anteversion in unilateral DDH in an early walking age group

Purpose

At present, the indications for femoral derotational osteotomy remain controversial due to the inconsistent findings in femoral neck anteversion in developmental dysplasia of the hip (DDH). Moreover, combined anteversion is not assessed in unilateral DDH using three dimensional-CT. Therefore, the purposes of our study were to observe whether the femoral neck anteversion (FA), acetabular anteversion (AA) and combined anteversion (CA) on the dislocated hips were universally presented in unilateral DDH according to the classification system of Tönnis.

Methods

Sixty-two patients with unilateral dislocation of hip were involved in the study, including 54 females and eight males with a mean age of 21.63 months (range, 18–48 months). The FA, AA and CA were measured and compared between the dislocated hips and the unaffected hips.

Results

Although no significant difference was observed in FA between the dislocated hips and the unaffected hips (P = 0.067, 0.132, respectively) in Tönnis II and III type, FA was obviously increased on the dislocated hips compared with the unaffected hips in Tönnis IV type. Increased AA on the dislocated hips was a universal finding in Tönnis II, III and IV types. Meanwhile, a wide safe range of CA from 24° to 62° was demonstrated on the unaffected hips.

Conclusion

Femoral derotational osteotomy seems not to be necessary in Tönnis II and III types in unilateral DDH. Femoral derotational osteotomy should be considered in DDH, especially in Tönnis IV type, if the CA is still above 62° and the hip joints present instability in operation after abnormal acetabular anteversion, acetabular index and acetabular coverage of the femoral head are recovered to normal range through pelvic osteotomy.     

How does soft tissue distribution affect anteversion accuracy of the palpation procedure in image-free acetabular cup navigation? An ultrasonographic assessment.

Navigation of the acetabular cup in total hip replacement (THR) is used to improve the reproducibility of acetabular component positioning. When the palpation of anatomic landmarks, which is necessary to determine the pelvic coordinate system, is performed epicutaneously, the question as to how uneven soft tissue distribution can influence navigation accuracy arises.To obtain data, the questionable soft tissue thickness was measured in 72 patients scheduled for THR. In addition, distances between the landmarks were recorded. On the basis of this information, we were able to calculate the expected misinterpretation of the anteversion given by a navigation system for each patient.The calculations suggest that a navigation system would have underestimated the anteversion on average by 2.8 degrees +/- 1.8 degrees. The median of anteversion misinterpretation was 2.4 degrees and its 95% confidence interval was calculated to be 2.2 degrees -3.0 degrees. No correlation with substantial significance between anteversion misinterpretation and the patients' biometrical data could be found.According to the current knowledge, acetabular cups in THR should be positioned within a range of 30 degrees -50 degrees of inclination and 10 degrees -30 degrees of anteversion. In comparison with these permitted +/- 10 degrees windows, the amount of misinterpretation that was found due to uneven soft tissue distribution seems to be acceptable.     

Snodgrass术联合去表皮组织瓣覆盖技术在小儿尿道下裂手术中的应用

目的：报道联合应用Snodgrass术与去表皮组织瓣覆盖技术治疗小儿先天性尿道下裂的效果。方法：回顾性分析2003年6月～2005年3月收治的68例9个月～11岁先天性尿道下裂患儿资料,其中远端型（包括阴茎头、阴茎体型）52例,阴茎阴囊型12例,近端型（阴囊型）4例,采用Snodgrass术及去表皮组织瓣覆盖技术一期尿道成形。观察其术后效果。结果：术后随访6～15个月,4例出现尿瘘．2例出现尿道狭窄。尿瘘及尿道狭窄者再次治疗均成功。结论：Snodgrass术是尿道下裂手术治疗的一种安全、有效的术式;同时与去表皮组织瓣覆盖技术联合。降低了术后尿瘘的发生率。提高了手术成功率。     

Effective in vivo radiation dose with image reconstruction controlled pedicle instrumentation vs. CT-based navigation

There is a rapid increase of computer-assisted surgery (CAS) in the spine for insertion of pedicle screws. In contrast to the traditional technique using fluoroscopy, CT is the primary source for surgical navigation systems. PURPOSE OF THE STUDY: To compare organ and effective doses of fluoroscopy-controlled versus computer-assisted pedicle screw insertion under the aspect of risk reduction and number needed to treat. MATERIALS AND METHODS: In 20 consecutive cases of traditional pedicle screw instrumentation under fluoroscopic control the effective doses were recorded in vivo and the organ doses then calculated. Simulating a spiral CT necessary for the 3-D-model for navigation we defined a spiral CT protocol for the instrumented levels and calculated organ and effective doses from Monte Carlo Results from CT examinations. RESULTS: Organ doses were clearly higher for the CT model than in any of the fluoroscopic procedures in vivo. The mean effective dose for the CT model was fifteen times higher than the fluoroscopic dose: 7.27 mSv versus 0.48 mSv. CONCLUSIONS: In experienced hands open pedicle screw insertion in the thoracic and lumbar spine using fluoroscopy-control requires a fifteen times lower radiation dose than do CT scans necessary for computer-assisted surgery. Regarding the published small percentage of neurological complications in traditional screw insertion technique the use of computer-assisted surgery in pedicle screw insertion using CT scan should be limited to carefully chosen indications. The development of navigation systems based on other data sources than CT should be encouraged.