CT-based surgical planning software improves the accuracy of total hip replacement preoperative planning

The present study is aimed to compare accuracy and the repeatability in planning total hip replacements with the conventional templates on radiographs to that attainable on the same clinical cases when using CT-based planning software. The sizes of the cementless components planned with new computer aided preoperative planning system called Hip-Op and with standard templates were compared to those effectively implanted. The study group intentionally included only difficult clinical cases. The most common aetiology was congenital dysplasia of hip (65.6%). The Hip-Op planning system allowed the surgeons to obtain a preoperative planning more accurate than with templates, especially for the socket. Assuming correct a size planned one calliper above or below that implanted the accuracy increased from 83% for the stem and 69% for the socket when using templates to 86% for the stem and 93% for the socket when using the Hip-Op system. The repeatability of the Hip-Op system was found comparable to that of the template procedure, which is much more familiar to the surgeons. Furthermore, the repeatability of the preoperative planning with the Hip-Op system was consistent between surgeons, independently from their major or minor experience. The study clearly shows the advantages of a three-dimensional computer-based preoperative planning over the traditional template planning, especially when deformed anatomies are involved. The surgical planning performed with the Hip-Op system is accurate and repeatable, especially for the socket and for less experienced surgeons.     

股骨近段CT扫描与全髋关节置换的术前计划

背景：做好全髋关节置换前假体型号预测的前提是对股骨近段的充分了解和精确测量,但X射线片仅提供一个平面图像,不能了解股骨近段横断面的情况,而股骨上段CT扫描可以提供更多信息。 目的：观察股骨近段CT扫描在全髋关节置换前计划中的作用。 方法：对61例进行初次全髋关节置换的患者行股骨近端CT扫描,选取股骨小转子最突出处上方2 cm股骨颈平面(T20)、股骨小转子最突出点处的股骨转子区平面(T0)和股骨干髓腔最狭窄处平面(N)的横断面CT影像。测量股骨颈平面髓腔长径、宽径、内侧径;小转子平面髓腔长径、内侧径;股骨峡部平面髓腔长径、宽径、皮质厚度。 结果与结论：股骨颈T20长径40.8~63.3 mm,平均(49.6±5.1) mm;T20宽径13.3~29.1 mm,平均(22.4±3.4) mm;T20内侧径7.2~14.6 mm,平均(10.6±1.6) mm。股骨转子区T0长径20.5~40.2 mm,平均(28.7±4.4) mm;T0内侧径4.3~13.0 mm,平均(8.1±1.7) mm。股骨峡部N长径8.2~22.4 mm,平均(14.1±3.1) mm;N宽径6.1~17.9 mm,平均(10.2±2.9) mm;N皮质厚度2.7~12.7 mm,平均(7.5±1.8) mm。提示股骨近端CT扫描可以提供更多的影像信息和更精确的测量数据,对全髋关节置换前计划有所帮助。     

全髋关节翻修术（48例50髋随诊分析）

目的评价人工全髋关节翻修术临床效果。方法自1984年1月～2006年4月,56例58髋行髋关节翻修术,男22例,女34例,年龄36～73岁,平均63岁。初次人工髋关节置换前诊断为股骨颈骨折28例,股骨头缺血坏死18例,髋关节发育不良骨关节炎9例,强直性脊柱炎1例。初次行股骨头置换术9例,其中骨水泥2例,生物型固定7例。全髋关节置换47例49髋。其中骨水泥30髋,生物型固定19髋。术后早期脱位2例,16髋因髋关节严重疼痛,45例47髋因无菌性松动行全关节翻修术。翻修手术中28髋行髋臼植骨,其中自体碎屑植骨17例18髋。自体碎骨屑加异体大块植骨10例。结果资料完整48例50髋获得随访,最长20年,最短4个月,平均随访时间为5年。经随访,患者髋关节基本无疼痛,X线片显示髋臼和股骨柄假体位置满意,无松动和感染征象,髋臼植骨后愈合良好。4例股骨柄假体正位X线片仅1区出现约1mm宽的透亮带,临床检查无松动迹象。Harris评分由术前的平均41.3分(10～70分)提高到术后的平均80.4分(55～97分)。结论全髋关节翻修手术的病例经随访,临床达到满意效果。     

髋关节表面置换三维可视化设计

背景：髋关节表面置换过程中二维图谱只能观察到三维解剖结构的某一个侧面,不能全面地把握整体的三维结构。 目的：利用个人计算机结合图像处理软件Amira 4.1对髋关节表面置换进行三维重建,建立髋关节表面置换的可视化数字模型。 方法：对1例髋关节表面置换后患者骨盆进行多排螺旋CT扫描,观测内置物的位置形态,将原始数据以.dicom格式输入个人PC,利用Amira软件,经剪切、分割、表面重建及体绘制等步骤,根据解剖结构特点,对骨盆及髋关节进行三维重建,获得立体形态的髋关节及内置物位置结构。 结果与结论：重建了骨盆、髋关节及内置物的形态构成,重建的三维结构可以多彩色、透明或任意组合显示,经不同角度观察,整体显示清晰、实体感强。在三维表面重建的图像中可清楚观察表面假体的位置形态,特别是可以立体直观显示全髋关节表面置换假体的大小、倾角、稳定性以及磋磨股骨头形态,并可精确测量。提示髋关节表面置换三维重建对基础研究、临床试验及手术规划具有重要价值,应用Amira软件可为三维建模提供基础。     

老年人髋关节置换术疗效分析

目的探讨全髋关节置换术(THR)对老年患者的临床价值。方法回顾分析我院2002年至2005年38例全髋关节置换术老年患者的手术效果,术后随访1~3年,平均2.4年。对术后髋关节功能进行评分。结果38例平均随访2.4年,无一例感染,无关节严重疼痛,功能阻碍及DVT发生。无术后关节早期脱位,无假体松动、断裂、下沉等并发症发生。随访表明髋关节置换术的优良率达92.1%,手术效果满意。结论全髋关节置换术对老年患者可解决患髋的疼痛,改善髋关节功能。是一种治疗老年髋部疾患安全有效的方法,但应严格掌握其手术适应证。     

31例人工髋关节翻修的临床分析

目的探讨初次人工髋关节置换后翻修的原因。方法对31例患者行全髋关节翻修术，对髋臼或股骨缺损者进行修复重建。通过术前X线片和术中所见，推测翻修原因。结果31例患者中共有30例得到随访，随访时间为6～36月，平均18．7月。Harris评分由术前的平均（32．56±17．31）分升高至术后平均（75．40±12．52）分。术后所有患者双下肢均恢复或保持等长，髋关节疼痛缓解。并发症为术中发生股骨骨折1例，无1例发生感染或髋关节脱位。结论引起人工髋关节置换术后翻修的主要原因是无菌性假体松动。翻修术中应合理地选择髋臼或股骨缺损的修复与重建方法，同时也应重视提高初次手术质量。     

Quality of life following total hip replacement

Orthopaedic surgeons have traditionally used disease-specific scoring systems that focus on relief of pain and improvement in function. However, these allow little scope for patient assessed outcomes such as quality of life. This study assessed quality of life before and after Total Hip Replacement (THR) using the Short Form 36 (SF-36) questionnaire. 100 patients were interviewed pre-operatively and 9 months to one year post-operatively. Data on waiting times/length of stay/complication rates were collected by reviewing clinical notes. The mean length of stay was 22.0 +/- 10.6 days, with a pre-operative length of stay of 5.0 days. 12 patients in all had a post-operative complication, including one post-operative death. There was a statistically significant improvement in overall SF-36 score (+19%) and in 7 out of the 8 parameters that make up the SF-36 score (p < 0.001). Patients undergoing THR in Navan showed a statistically significant improvement in their quality of life post-operatively. Complication rates were in keeping with international norms. It is apparent that patients receive a high quality of care.     

Cost analysis of primary total hip replacement

Arthritis of the hip is a cause of significant morbidity to the sufferer, for which total hip replacement is firmly established as an effective treatment. In order to assess the cost utility and benefit of total hip replacement, we compared the costs incurred to the health benefit accrued as measured by improvement in pre to post operative Harris hip scores, WOMAC osteoarthritis indices and SF 36 scores. Our calculations suggested the average unit cost of a total hip replacement at Cappagh National Orthopaedic Hospital, in 1999, to be in the region of 6,500 pounds. Cost utility was calculated as cost per QALY. Cost benefit was expressed as cost per 10 point increments in Harris hip scores, WOMAC and SF 36 scores. We conclude that total hip replacement is a worthwhile and efficient investment of health resources.     

Diagnosis of infection after total hip replacement

Subclinical infection in patients with pain following total hip replacement (THR) is an underestimated condition that needs consideration because it mimics aseptic loosening, contributes to periprosthetic osteolysis, and necessitates proper treatment. We aimed to define the reliability of diagnostic parameters that are routinely used before revision surgery for the assessment of infection. A continuous series of 26 subjects who underwent THR revision surgery was considered, including 21 cases diagnosed as aseptic loosening (group A) and 5 hip revisions with a clinical diagnosis for infection (group B). Seven subjects at the time of the primary arthroplasty were used as negative controls (group C). Technetium-99m labeled hydroxymethylene diphosphonate [(99m)Tc-HDP]- and technetium-99m hexamethylpropyleneamine oxide [(99m)Tc-HMPAO)]-labeled granulocyte scintigraphy, histology of peri-implant tissues, laboratory tests for inflammation, and microbiology were performed. Scintigraphy was positive for loosening [positive (99m)Tc-HDP scan] but negative for infection [negative (99m)Tc-HMPAO-labeled granulocyte scan] in all group A patients, whereas in 11 cases (52%) a positive culture was unexpectedly obtained. Histology showed conflicting results: Polymorphonuclear cells (PMNs) were found only in 5 of 11 culture-positive patients, whereas in 2 cases the presence of PMNs did not correspond to a positive culture. In group B patients, both isotope scans and microbiology were found to be positive. All control subjects (group C) had negative cultures. In our opinion, smoldering infection could be present in a significant proportion of cases of failed hip implants currently diagnosed as "nonseptic." The inflammatory response to wear debris and the presence of superimposed, slowly growing bacteria could act synergically, both contributing to the pathogenesis of periprosthetic osteolysis.     

人工全髋关节假体置换治疗运动性髋损伤的理论与实践☆

背景：全髋关节表面置换尽可能保持了髋关节原有的力学性能,置换后关节稳定性及活动度好,且无明显的年龄限制。 目的：探讨人工髋关节假体在髋关节运动损伤治疗中的临床应用,以及髋关节假体置换治疗的材料与方法进展。 方法：应用计算机检索1998-01/2011-10 PubMed数据库及中国知网数据库有关生物材料与组织工程髋关节的文献,英文检索词“hip joint injury,artificial hip joint,hip replacement,hip resurfacing arthroplasty”,中文检索词“髋关节损伤,人工髋关节,人工髋关节置换,全髋关节表面置换”。最终纳入符合标准的文献41篇。 结果与结论：严重髋关节运动损伤应行人工髋关节置换,以恢复患者的生活能力,甚至一定程度的运动能力。目前人工髋关节假体置换的关键因素在于假体材料,假体材料主要有金属材料、陶瓷材料高分子材料、新一代骨水泥等,各自具有一定优点与缺点,由于随访时间和临床观察周期较长,各种材料的疗效还需要进一步研究。计算机模拟髋关节的三维有限元分析成为研究的热点,将运动生物力学与材料科学结合,对新材料的研发与检验是制造满足组织工程学人工髋关节假体的要求,达到修复和重建目的的重要途径。     

影响人工全髋关节置换稳定性的因素

背景：人工全髋关节置换后出现假体松动的现象较常见,了解影响人工全髋关节稳定性的因素对提高人工全髋关节置换疗效是十分必要的。 目的：总结近年人工全髋关节置换稳定性影响因素的最新研究进展,进一步认识人工全髋关节的稳定性。 方法：应用计算机检索中国期刊全文数据库1997-01/2010-12有关人工髋关节置换后假体无菌性松动的相关文章,检索词“人工关节,置换,稳定性”。检索文献量总计98篇,最终纳入符合标准的文献30篇。 结果与结论：人工全髋关节置换稳定性的影响因素及发病机制较为复杂,其主要原因是力学因素,其次是生物学因素,它们共同结果是造成骨吸收、骨溶解,最终导致假体松动、骨质破坏。其过程还与许多细胞因子的参与密切相关。针对引起人工全髋关节稳定性的影响因素,可以从关节材料、安放角度、抑制磨损颗粒移动、促进成骨及抑制骨吸收等方面来防治。     

无柄全髋关节置换术治疗强直性脊柱炎髋关节强直的临床体会

目的探讨强直性脊柱炎(AS)髋关节强直行无柄全髋关节置换术的方法与疗效.方法回顾性分析2006年1月~2011年10月,对9例14髋强直性脊柱炎患者进行髋关节无柄全髋置换术.结果本组随诊时间1~5年,术后1例1髋出现脱位.4髋发生轻度异位骨化,根据 Brooker 分期,Ⅰ级3髋,Ⅱ级1髋.术后患者髋关节活动度得到明显改善,生活质量得到大幅度提高.结论无柄全髋关节置换术是一种强直性脊柱炎患者髋关节强直有效的治疗方法.     

Bone remodeling assessment after total hip replacement

It is known that total hip arthroplasties (THA) lead to adaptative remodeling changes resulting in periprosthetic bone loss. DEXA is recognized as the most precise and accurate method for quantifying bone mineral density (BMD) in humans. The present study compares over two years after THA, DEXA data to those of urinary deoxypyridinoline (uDPYR), a pyridinium crosslink of bone collagen fibrils proven to be a reliable bone resorption marker. 41 patients (21 postmenopausal female, 20 male) underwent cemented THA. Urinary excretion of DPYR was determined using ACS : 180 SE (Bayer Diagnostics) and normalized for creatinine excretion while periprosthetic BMD (g/cm2) was measured (QDR 4500, Hologic), at post-operative day, 3 months, 1 year and 2 years after surgery. The 7 periprosthetic subregions (R1-R7) of the Gr en method are the regions of interest for evaluating bone remodeling process. uDPYR showed a significant decrease between postoperation and 1 year: 10.6 0.80 vs 4.8 0.6 nmol/mmol, p < 0.0001 (Wilcoxon Test for paired samples and statistical significance accepted at p < 0.05) and non significant variation between 1 and 2 years. Between post-operation and 3 months global and regional BMDs decrease significantly (p < 0.04) followed by an increase in distal BMD (R3, R4, R5). During the second year BMD increases also for other regions. At 2 years BMD in distal regions is recovered except in the proximal R7 when comparing post-operation and 2 years, pattern consistent with literature. Thus, a discrepancy is observed between uDPYR and DMO results that does not allow us to use a bone resorption urinary marker to monitore local bone periprosthetic remodeling.     

Soft-tissue response to total hip surface replacement

Tissue reaction to prosthesis wear debris and its relationship to prosthetic loosening was investigated. Eighteen dogs underwent hip surface replacement; 6 animals accounted for 6 control and 6 carbon hips, and 13 experimental animals accounted for 13 implanted carbon and 13 cobalt-chromium-molybdenum (CoCrMo) prostheses. Both kinds of prostheses articulated against a high-density polyethylene acetabular component. One year after implantation, tissue response to the prostheses was evaluated according to a semiquantitative method, and a total tissue score indicating the degree of tissue response was obtained. The total tissue score was then compared with the normalized final vertical ground reaction force (GRF) for each hip in the animals with bilateral hip replacements. Compared with the controls, significantly greater tissue response was seen in both kinds of prosthetic hips (p = .001). No statistically significant difference in the tissue response of the two types of hip prostheses was noted, although the tissue response score of the CoCrMo demonstrated a trend toward more severe reaction than the carbon. No statistical difference in tissue reaction was noted for loosened components as compared with tightly fixed components. Amount of wear debris was the best predictor of component loosening. Gait analysis demonstrated a statistically significant negative correlation between GRF and total tissue score (p = .036), and between GRF and wear debris score (p = .034). The results of this study suggest that GRF may predict the amount of wear debris in the tissues surrounding a total hip surface arthroplasty, and that severity of pain is related to the degree of tissue response.     

Metal ion release after total hip replacement

The concentration of cobalt (Co), chromium (Cr), molybdenum (Mo), nickel (Ni), iron (Fe) and zinc (Zn) was measured using neutron activation analysis in tissue taken from an 81 year old female at necropsy. The patient had bilateral cobalt chromium molybdenum (Co-Cr-Mo) total hip replacements: one, a metal-on-metal had been in place for 14 years, the other a metal-on-plastic for 5.5 years. Although the metal-on-metal side had become painful, the patient remained active until she died. The measurements indicated that the concentrations of Co and Cr in the lung, kidney, liver and spleen were up to fifty times ‘Standard Man’ values. High values occurred also in the urine and in the hair. The tissue adjacent to the metal-on-metal joint was heavily laden with metal wear debris, whereas that adjacent to the metal-on-plastic joint was relatively uncontaminated. The concentration varied with distance from the implant. Co predominated in the urine, whereas Cr predominated near the implants. The existence of such high levels, especially in the organs, is a possible cause for concern.     

Probabilistic analysis of an uncemented total hip replacement

This paper describes the application of probabilistic design methods to the analysis of the behaviour of an uncemented total hip replacement femoral component implanted in a proximal femur. Probabilistic methods allow variations in factors which control the behaviour of the implanted femur (the input parameters) to be taken into account in determining the performance of the construct. Monte Carlo sampling techniques were applied and the performance indicator was the maximum strain in the bone. The random input parameters were the joint load, the angle of the applied load and the material properties of the bone and the implant. Two Monte Carlo based simulations were applied, direct sampling and latin hypercube sampling. The results showed that the convergence of the mean value of the maximum strain improved gradually as a function of the number of simulations and it stabilised around a value of 0.008 after 6200 simulations. A similar trend was observed for the cumulative distribution function of the output. The strain output was most sensitive to the bone stiffness, followed very closely by the magnitude of the applied load. The application of latin hypercube sampling with 1000 simulations gave similar results to direct sampling with 10,000 simulations in a much reduced time. The results suggested that the number of simulations and the selection of parameters and models are important for the reliability of both the probability values and the sensitivity analyses.     

全髋关节置换术后假体周围组织的病理生理

全髋关节置换术后远期失败的主要原因是假体无菌性松动和局部软组织不良反应。在置换术后关节假体的长期使用过程中,假体微动、磨损微粒/离子刺激、液压波动、应力遮挡等因素共同作用下,导致假体周围骨组织丢失和软组织不良反应。既往文献对上述因素单一作用导致骨溶解的讨论较多。本文主要从关节置换术后病理生理进程的角度出发,探讨假体微动、磨损微粒/离子刺激、液压波动等因素在人工关节置换术失败中的协同作用。上述致病因素所导致的炎性假瘤、骨溶解甚至是无菌性松动,均可以是无临床症状的,但其持续进展,终将导致置换手术失败。     

人工全髋关节置换后33例翻修原因解析

背景：人工髋关节置换后出现感染、假体松动、假体磨损断裂、骨溶解、复发性脱位等并发症的数量逐渐增多,最终导致行全髋关节翻修。 目的：分析人工全髋关节置换后进行翻修的原因和治疗措施。 方法：对33例患者全髋关节翻修的原因、假体选择、骨缺损处理及康复进行分析研究。其中髋臼有21例行普通金属杯加内衬置换、8例行大头臼杯置换、4例行聚乙烯臼杯置换。股骨柄有15例行普通柄(11例应用骨水泥固定)置换、18例行加长柄置换(9例应用骨水泥、6例为组合型柄)。 结果与结论：33例患者全部获得随访,翻修后随访24-60个月,平均随访36.5个月;翻修后伤口愈合良好,假体固定可靠,未再次出现感染脱位患者;髋关节功能均得到了较大的改善,Harris评分：翻修前平均为37.1分,翻修后平均为91.3分。中短期临床随访结果示,若翻修手术指征正确,骨缺损处理得当,翻修假体选择正确,行一期人工全髋关节翻修可以获得良好的临床疗效。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程全文链接：     

模拟全髋关节置换后股骨假体的稳定性

背景：国内外关于髋关节置换后股骨的压缩力学实验研究较多,因此研究髋关节置换后股骨的扭矩、扭转角、载荷-位移关系非常重要。对比分析传统型假体和解剖型假体的压缩、扭转力学特性,对于髋关节置换及人工假体的稳定性研究具有重要意义。 目的：通过模拟髋关节置换后股骨的轴向压缩和扭转实验,对比分析传统型和解剖型人工假体的稳定性,为临床提供生物力学参数。 方法：取股骨左右侧标本共12个,其中左侧6个标本保留股骨颈作为解剖型钛合金人工关节假体组,右侧6个标本去除股骨颈作为传统型钴铬钼人工关节假体组。分别将两组标本置于电子万能试验机工作台上,以     5 mm/min的实验速度对标本施加压应力,读取20,40,60,80,100 N时所对应的位移值。之后取两组标本,将标本两端置于扭转试验机夹头内,以1 (°)/s的实验速度对标本施加扭矩,读取5,10,15,20 N•m扭矩时所对应的扭转角值。 结果与结论：在100 N外力作用下,传统型假体位移为(2.03±0.06) mm,解剖型假体位移为(1.83±0.05) mm;在20 N•m扭矩作用下,传统型假体扭转角为(21.7±0.7)°,解剖型假体扭转角为(13.2±0.4)°。解剖型假体在100 N作用下的位移和在20 N•m扭矩作用下的扭转角均小于传统型假体组,差异有显著性意义(P < 0.05)。提示解剖型假体和传统型假体具有不同的压缩和扭转力学特性,解剖型假体置入股骨后具有较好的稳定性。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Disparities in the utilization of high-volume hospitals for total hip replacement

ObjectiveHigher hospital surgical volumes have been associated with lower complication rates following total-hip replacement. The objective of this study was to identify the characteristics of patients who undergo total-hip replacement at high-volume hospitals and their differences from those who receive care at low-volume hospitals.MethodsDischarge data from patients undergoing total hip replacement in California from 1995 to 2005 were analyzed. Hospitals were classified into 3 tiers of low, intermediate, or high surgical volume. The relationships between race/ethnicity and income to utilization of low-volume and high-volume hospitals were examined by creating logistic regression models that include patient covariates such as age, gender, and comorbidity.ResultsThis study analyzed 138399 cases of primary total-hip replacements during the study period. Patients of Hispanic ethnicity, or black or Asian race had higher relative risk ratios for being treated at a low-volume center compared to white patients.ConclusionsThere are disparities in the characteristics of patients receiving care at hospitals performing a high volume or low volume of total-hip replacements. Hispanic ethnicity, and black and Asian race were statistically significant predictors of utilization of a low-volume hospital.