Inaccuracies in the assessment of femoral anteversion in proximal femoral replacement prostheses

Accurately judging anteversion of proximal femoral replacement prostheses (PFRPs) during insertion can be difficult and may affect performance/stability. We designed a gravity goniometer jig, which attaches directly to the prosthesis, to improve rotational placement. Our hypotheses were that surgeons cannot accurately estimate anteversion in the context of a PFRP and that our jig would improve rotational placement. In our model, a 15-centimeter PFRP was placed in a saw-bones femur set in a lateral position. The prosthesis could rotate into anteversion/retroversion while the femur was fixed. Orthopedic residents and surgeons made 2 attempts to place the prosthesis into 15 degrees of anteversion; first without, then with the jig. Each attempt was recorded by photograph and angle-measuring jig. Nineteen surgeons and 28 residents participated. Without the jig, the mean PFRP anteversion was 18.3 degrees (range, 1 degrees -50.5 degrees ; SD, 9.6) compared to 14.3 degrees (range, 12.5 degrees -15.5 degrees ; SD, 0.7) using the jig (P = .006). Without a jig, the mean anteversion of resident-placed endoprosthesis was 18.4 degrees (range, 3 degrees -36 degrees ; SD, 8.1) compared to 18.1 degrees (range, 1 degrees -50.5 degrees ; SD, 12.1) (P = .91) recorded for attending physicians. The angle measurements from the jig and photographs were statistically equal. The placement of the PFRP into proper anteversion was more accurate with the aid of the jig. Simple jigs, such as the one developed for this study, may improve rotational placement of PFRPs.     

Hydroxyapatite and revision of femoral hip prostheses

Summary Implants coated with hydroxyapatite (HA) are of very special importance in revisions of total hip prostheses. As far as the fernur is concerned, the rapid bony reconstruction due to the osteoconductive properties which ensure in particular the filling of defects of bony contact guarantee excellent secondary stabilization of the implants, provided that the mechanical assembly secured at operation be stable. The results of a personal series of 46 patients confirm the efficacity of the HA coating by demonstrating the quality of bony reconstruction and the long-term stability of the implants with satisfactory clinical results.     

The rate of hip osteoarthritis in patients with proximal femoral fractures versus hip contusion

Summary  

We found no difference in the rate of radiological hip osteoarthritis in the injured hip when comparing 349 patients with proximal femoral fractures and 112 patients with hip contusion. There was, however, a tendency for more osteoarthritis in patients with trochanteric fractures than in patients with femoral neck fractures.     

股骨头骨坏死范围对髋关节表面置换术后股骨近端力学分布的影响

目的探讨髋关节表面置换术后股骨头骨坏死范围对股骨近端与假体松动或股骨颈骨折相关的应力分布的影响。方法依据基于连续CT断层图像构建的股骨三维图形和髋关节表面置换假体，采用计算机辅助技术，建立股骨头部无坏死和前后位坏死角分别为60°、80°、100°、120°、140°的表面置换三维有限元模型，单腿负重条件下，模拟坏死骨未清除及清除后填充骨水泥的情形进行受力分析。结果骨坏死范围对股骨颈部的应力分布影响微小。股骨头近端骨质出现明显的应力遮挡。当坏死角≤80°时，骨水泥界面和头颈交界骨质中的Von Mises等效应力峰值变化较小；当坏死角≥100°时，应力峰值变化明显，其中水泥层外上缘的峰值增幅为22．3％和27．3％（坏死角120°和140°），头颈交界外上缘骨质的峰值增幅为13．2％、28．3％和53．3％（坏死角100°、120°和140°）。填充骨水泥后，主要应力集中区的等效应力峰值逐渐减小或变化不明显。结论髋关节表面置换术改变了股骨头内应力分布；股骨头近端出现明显的应力遮挡，允许股骨头负重区出现小的骨坏死（坏死角≤80°）；坏死角≥100°的骨坏死，是否适于髋关节表面置换术还需深入研究。     

The use of structural proximal femoral allografts in complex revision hip arthroplasty

Between April 1992 and November 1998 we used 34 massive proximal femoral allografts for femoral reconstruction at revision hip arthroplasty. Seven patients have died and two have been lost to follow-up. There were thus 25 grafts in 24 patients for review. The mean follow-up was 53 months (16 to 101). By the time of the review two patients had undergone a further revision for failure of the allograft. Another had required secondary plating and grafting at the graft-host junction for symptomatic nonunion. One had recurrence of deep sepsis and was being managed conservatively. Trochanteric union was considered to have occurred radiologically in 16 of the 25 grafts and union at the host-graft junction in 20. Resorption of the allograft was significant in only two hips. We recommend this technique in cases in which femoral bone loss has been catastrophic.     

立体影像学分析对组配式全髋关节置换术后股骨假体迁移的早期评估

目的 探讨立体影像学分析(roentgen stereophotogrammetric analysis,RSA)对全髋关节置换术后股骨假体迁移的评估价值.方法 2009年5月至2010年4月,行组配式全髋关节置换37例,男25例,女12例;年龄58～72岁,平均(60.23±5.64)岁.退行性骨关节炎32例,股骨颈骨折3例,髋关节发育不良2例.术后3、6、12、24个月采用Harris髋关节评分评估髋关节功能及RSA评估股骨假体的早期迁移度.结果 Harris髋关节评分从术前(26.36±10.56)分提高至术后不同随访时间点的(78.24±12.72)分、(84.51±16.05)分、(86.72±9.34)分及(87.55±8.97)分,与术前比较差异均有统计学意义.无假体翻修病例,3例有轻微的大腿痛.RSA评估发现早期迁移幅度个体差异较大,术后3～6个月存在较高的初始迁移.36例于术后24个月达到临床和生物学稳定,1例表现为假体进行性迁移.股骨假体向远端迁移(1.37±0.59) mm、向后迁移(1.37±0.54) mm,与术前差异有统计学意义.术后24个月内股骨假体向远端迁移与向后迁移呈正相关(r=0.3,P=O.O1),假体在横断面和矢状面上呈现出相对宿主骨界面稳定固定的趋势,股骨假体向远端及向后的倾斜或旋转移位主要发生在术后3个月内.不同尺寸的股骨头假体和不同偏心距的组配式股骨颈假体与发生在各个方向的迁移度无相关性.结论 RSA为组配式全髋关节置换术后股骨假体迁移度的早期评估提供了客观依据,可用于评估人工关节假体的早期稳定性.     

Total hip arthroplasty in patients with proximal femoral deformity

Most proximal femoral deformities encountered during hip arthroplasty are secondary to developmental processes, previous osteotomy, or fracture. A classification method is proposed in which deformities are categorized anatomically by level. Anatomic deformity levels include: greater trochanteric deformities, femoral neck deformities, metaphyseal level deformities, and diaphyseal level deformities. Deformities at each level may be angular, rotational or translational, abnormal bone size, or a combination thereof. Treatment is individualized according to patient needs and the anatomy of the deformity. Careful preoperative planning helps predict prosthesis requirements and technical challenges. If cemented implants are used, care must be taken to obtain reasonable alignment and a continuous cement mantle. For uncemented implants, obtaining a good fit is challenging and there is a risk of intraoperative fracture. Access to a wide range of implants helps the surgeon treat unique femoral geometries. Implants fixed in the diaphysis allow some proximal femoral deformities to be bypassed. Modular or custom implants simplify treatment of certain deformities. For patients with severe deformities, femoral osteotomy may be required. Successful osteotomy requires correcting the deformity, maintaining vascular supply of fragments, obtaining fixation of osteotomy fragments (with the implant or adjunctive fixation), and obtaining implant stability. Although most deformities can be treated during hip arthroplasty, occasionally there is a role for two-stage treatment: deformity correction followed later by arthroplasty.     

Corrosion between the components of modular femoral hip prostheses.

We studied the tapered interface between the head and the neck of 139 modular femoral components of hip prostheses which had been removed for a variety of reasons. In 91 the same alloy had been used for the head and the stem; none of them showed evidence of corrosion. In contrast, there was definite corrosion in 25 of the 48 prostheses in which the stem was of titanium alloy and the head of cobalt-chrome. This corrosion was time-dependent: no specimens were corroded after less than nine months in the body, but all which had been in place for more than 40 months were damaged. We discuss the factors which may influence the rate of these changes and present evidence that they were due to galvanically-accelerated crevice corrosion, which was undetected in previous laboratory testing of this type of prosthesis.     

动力髋螺钉与股骨近端髓内钉治疗不稳定型股骨粗隆间骨折的临床比较

目的：比较动力髋螺钉（ DHS）和股骨近端髓内钉（ PFNA）两种内固定治疗不稳定型股骨粗隆间骨折的临床疗效。方法自2008年5月至2013年4月间对95例老年股骨粗隆间不稳定型骨折患者进行回顾性研究,患者分为DHS组45例与PFNA组50例,比较两组的手术时间,术中出血量,下地行走时间,骨折愈合时间及髋关节功能等数据。结果 PFNA组和DHS组在手术时间,术中出血量,下地行走时间有显著差异,而在骨折愈合时间无明显差异,对于不稳定型股骨粗隆间骨折, PFNA组的髋关节功能优良率高于DHS组。结论对于不稳定的股骨粗隆间骨折,PFNA系统具有出血少,手术时间短,恢复快等的优点。     

Roentgenographic changes in proximal femoral dimensions due to hip rotation

Three human adult femurs were examined using anteroposterior (AP) roentgenograms in anatomical position and in 15 degrees, 30 degrees, and 45 degrees of internal and external rotation. Relatively small (15 degrees or less) amounts of femoral rotation can cause significant changes in proximal femoral dimensions on supine AP hip roentgenograms, and the magnitude of these changes increases with rotation. Fifteen degrees of rotation can change it by almost 3 mm. These changes are comparable to the medullary canal expansion of a normal adult femur over a five- to ten-year period. These changes in measured proximal femoral dimensions with rotation necessitate either an improved roentgenographic technique or precise rotational matching of standard supine roentgenograms to obtain accurate measurements of their changes over time.     

股骨颈组配式假体在全髋关节置换术后偏心距重建中的作用

目的 探讨股骨颈组配式假体对全髋关节置换术后偏心距重建的意义.方法 对2009年6月至2012年6月使用股骨颈组配式假体行全髋关节置换术的75例患者进行回顾性研究,男42例,女33例;年龄44～83岁,平均(64.7±12)岁.左髋40例,右髋35例.术前Harris髋关节功能评分32～65分,平均(54±6)分.均采用M/L Taper with Kinectiv假体系统.术前应用模板技术预计假体大小及偏心距,术中实体测量,结合术前计划和术中情况选取大小合适的股骨颈假体,恢复偏心距,重建髋关节外展力臂.术后于X线片上测量偏心距及下肢长度.术后l、3、6、12个月及以后每年随访一次,采用Harris髋关节功能评分评价疗效.结果 股骨偏心距均得到重建,误差从-3.0～3.0 mm,平均(1.3±0.3)mm.双下肢长度差平均(3.0±0.8) mm.术后随访6～36个月,平均19.7个月.术后12周站立位髋关节外展角平均40°±10°;Harris髋关节功能评分65～94分,平均(86±13)分,与术前比较差异有统计学意义(t=19.360,P=0.000).末次随访时Harris髋关节功能评分78～98分,平均(95±15)分.随访期间未出现关节脱位和髋臼股骨撞击征病例.结论 使用股骨颈组配式假体可在不影响下肢长度的情况下恢复患肢的股骨偏心距,获得良好的髋关节外展肌力、活动度及稳定性,术后近期并发症发生率低.     

股骨近端缩短及全髋置换术治疗陈旧股骨颈骨折伴严重髋关节脱位

目的 探讨陈旧股骨颈骨折伴严重髋关节脱位的有效治疗方法及临床疗效。方法 自1996年4月采用股骨近端缩短及全髋置换术治疗7例陈旧股骨颈骨折伴严重的髋关节脱位的患者。结果 7例患者平均为51岁,术后随访平均为27．3个月,在近期随访过程中,按Harris评分由手术前的36．7分增加至术后84．3分,髋臼及股骨柄假体位置良好,未出现假体松动和下沉,也未出现截骨处骨不愈合。结论 股骨近端缩短及全髋置换术治疗陈旧股骨颈骨折伴严重髋关节脱位,近期疗效十分满意,其后期疗效有待进一步随访观察。     

全髋关节置换术后股骨近端应力遮挡

股骨近端应力遮挡效应是全髋关节置换(THA)术后的普遍现象,是引起股骨近端骨丢失的重要原因之一.测量骨丢失程度可以评估应力遮挡水平.该文综述了THA术后应力遮挡所致股骨近端骨丢失的3种常见诊断方法及其临床应用.早期研究认为THA术后应力遮挡与临床症状明显相关,但近年研究结果则否认了这一看法,其临床意义需要进一步深入研究.     

Minimal stress shielding with a Mallory-Head titanium femoral stem with proximal porous coating in total hip arthroplasty

Background  

As longevity of cementless femoral components enters the third decade, concerns arise with long-term effects of fixation mode on femoral bone morphology. We examined the long-term consequences on femoral remodeling following total hip arthroplasty with a porous plasma-sprayed tapered titanium stem.     

股骨近端Z形短缩截骨全髋置换术治疗成人CroweⅣ型发育性髋关节脱位

目的 探讨股骨近端Z形短缩截骨全髋置换术治疗CroweⅣ型成人髋关节发育不良的手术方法和临床疗效.方法 2000年7月至2006年2月,对13例CroweⅣ型成人发育性髋关节脱位继发骨关节炎患者行全髋关节置换术,同时采用股骨近端Z形短缩截骨.回顾性分析13例患者的临床资料,其中左髋9例,右髋4例.术前Harris评分36.9分.结果 所有患者均获得随访,随访时间4～55个月,平均32个月.Harris评分术后增加至84.1分.患者均能自行下地行走,步态明显改善,髋关节功能良好.结论 股骨近端Z形短缩截骨及全髋关节置换术是治疗Crowe Ⅳ型成人髋关节发育不良继发骨关节炎的有效方法,但手术难度大.其后期疗效有待进一步随访观察.     

Transfer of metallic debris after dislocation of ceramic femoral heads in hip prostheses

Introduction: Main reasons for the early revision of total hip arthroplasties are aseptic loosening as a result of wear debris caused by polyethylene particles, and postoperative dislocations. In revision arthroplasty of the hip metallic deposits were frequently found on femoral heads after dislocation or repositioning in total hip arthroplasties with metal back acetabular components. Materials and methods: In this study we examined ceramic femoral heads from alumina-on-alumina and alumina-on-polymer pairings, respectively. All the heads resulted from revision of total hip replacement with a titanium containing acetabular component and showed metallic deposit on their surface. The metallic deposit was characterized by environmental scanning electron microscopy, energy dispersive X-ray spectroscopy and laser scanning microscopy. Results: The metallic deposits covered areas between 5 mm² and 8 cm² and reached a maximum height of 30 μm. They were shown to consist of titanium, and thus resulted from contact between the femoral head and the posterior part of the metal back. In case of twofold dislocated alumina-on-alumina pairings the titanium deposits showed different roughness profiles, whereas no differences were detectable for alumina-on-polymer pairings. Conclusion: From the obtained results it can be concluded, that titanium deposited onto a femoral head during dislocation will be abraded within the harder alumina-on-alumina bearing couple during normal gait and will subsequently be released into the body by synovial fluid. In case of a ceramic-on-polymer bearing the deposited metal seems to be more harmful. The increased surface roughness of the femoral head within the tribological pairing probably initiates damage of the polymeric acetabular inlay and increases the wear of the bearing surface through a third-body wear mechanism resulting in the release of high amounts of PE.