High-turnover periprosthetic bone remodeling and immature bone formation around loose cemented total hip joints.

Aseptic loosening and periprosthetic osteolysis are the major problems awaiting solution in total hip surgery. The clinical investigation focused on the analysis of periprosthetic bone remodeling to clarify one important key event in the cascade of periprosthetic connective tissue weakening and osteolysis around loose artificial hip joints. Twelve acetabular bone samples adjacent to granulomatous synovial-like membrane of loose hip prosthesis were retrieved at revision surgery and processed for Villanueva bone staining for morphological observation and bone histomorphometric analysis. Eight well-fixed bony samples were used as control. Although osteoclastic surface and eroded surface by osteoclasts were evident in the periprosthetic bone from loose hip joints (p = 0.003 and p = 0.027), increased osteoid/low-mineralized bone matrix (p < 0.001) and osteoid width (p < 0.001) also were significant findings in structural analysis. In addition, not only elevated mineral apposition rate (MAR; p = 0.044) but also increased mineralizing surface (p = 0.044) and bone formation rate (BFR; p = 0.002) in loose periprosthetic bones were shown in dynamic data analysis. These results were confirmed by precise morphological observation by confocal laser scanning microscopy. Active coupling of bone formation and resorption and increased osteocytes with abundant bone canalicular projections were found in combined with the presence of immature bone matrices (osteoid and low-mineralized bone areas) in periprosthetic bones from loose hip joints. These results indicated that active osteoclastic bone resorption and/or defective bone formation are coupled with monocyte/macrophage-mediated foreign body-type granuloma in the synovial-like interface membrane of loose hip joints. Thus, this unique high-turnover periprosthetic bone remodeling with bad bone quality probably is caused by the result of cellular host response combined with inappropriate cyclic mechanical loading. The fragile periprosthetic bone may contribute to hip prosthesis loosening.     

Cancellous allograft in revision total hip arthroplasty. A clinical review

There are numerous indications for the use of cancellous allograft bone in the context of revision hip arthroplasty. These indications range from the well-documented use of morselized bone chips to fill cavitary defects during cementless acetabular reconstructions--in which complete or near-complete graft remodeling is expected--to the use of particulate allografting with bipolar hemiarthroplasty for acetabular revision, which largely has been abandoned because of frequent component migration, graft resorption, and clinical failure. Most other indications, including femoral and acetabular impaction allografting techniques, curettage of osteolytic defects with component retention, and complex reconstructions using acetabular reconstruction rings or cages with cancellous donor bone, are controversial but are supported by published clinical series. The current study reviews the literature on cancellous allografting in revision total hip arthroplasty.     

全髋关节翻修术中髋臼假体的选择和髋臼骨缺损的处理

目的探讨全髋关节翻修术中髋臼假体的选择和髋臼骨缺损的处理。方法2002年1月至2007年6月收治资料较完整的全髋关节翻修术患者共55例，其中行髋臼假体翻修术的患者有36例，男8例，女28例；年龄52～86岁，平均73岁。左髋13例，右髋23例。髋臼翻修原因：髋臼假体松动20例，髋臼和股骨假体均有明显松动12例；头臼不匹配2例；髋臼假体位置不良导致复发性脱位2例。髋臼骨缺损21例，按照美国矫形外科学会（AAOS）分类标准：Ⅰ型：节段性骨缺损6例；Ⅱ型：腔隙性骨缺损9例；Ⅲ型：混合型骨缺损6例。结果36例中，4例仅翻修髋臼侧假体，保留原股骨假体；3例更换了磨损严重的聚乙烯内衬，未予更换金属假体，其余29例均行全髋关节置换翻修术。髋臼骨缺损21例中，6例使用颗粒骨打压植骨＋骨水泥假体，2例为结构性和颗粒性打压植骨＋骨水泥假体，9例为结构性植骨＋颗粒打压植骨后，使用金属加强环＋骨水泥假体，1例为结构性植骨后，使用常规髋臼假体，3例仅对局部骨缺损部位进行植骨未予更换稳定的金属假体。随访时间6～68个月，平均39个月。Harris评分由术前的平均48分，提高至随访时平均89分。结论机械性磨损是人工髋关节松动翻修的主要原因；翻修时，假体的选择和骨缺损的处理要根据患者个体情况差异和术中具体情况综合考虑；周密的术前计划、准备多种类型髋臼假体供术中选择、充分自体和异体植骨是保证手术顺利进行的根本。     

髋关节翻修术中髋臼骨缺损的处理与重建

目的探讨髋关节翻修术中髋臼骨质缺损的处理和重建方法。方法对28例髋关节置换术后髋臼骨缺损的患者进行翻修,观察术后随访X线片上的髋臼假体及周围骨质变化情况,并对髋关节行Harris功能评定。结果 28例均获随访,随访时间12～184个月,平均61.6个月。1例术后出现脱位,2例术后出现骨溶解并伴患髋疼痛。7例术后随访的X线片上出现髋臼的骨溶解,但髋臼假体无松动表现,患髋无疼痛,患髋功能不受影响。至末次随访为止,25例髋（89%）获得良好的稳定性。术前Harris评分平均31.8分（14～57分）,末次随访时平均85.2分（46～99分）。两组数据具有显著性差异。结论充分的术前准备是手术顺利进行并获得良好效果的一个重要前提,植骨的方式和翻修假体的选择还需结合术中对骨缺损的评价。髋臼假体表面被自体骨覆盖超过50%,可考虑行植骨加非骨水泥型髋臼假体置换;自体骨覆盖不足50%,宜行骨水泥型髋臼假体置换。如骨缺损面积较大,可行加强环等翻修。从随访中可见,颗粒骨打压植骨是治疗髋臼骨缺损可靠的方法。     

The fate of massive allografts in total hip acetabular revision surgery.

A series of 23 major load-bearing acetabular allografts done in conjunction with revision total hip arthroplasty were prospectively evaluated. This study includes cases with a minimum 2-year follow-up period. The procedures were performed using noncemented porous-coated acetabular components with pegs. In seven acetabula there was no change in cup position when compared with the initial postoperative roentgenogram (35%). Six acetabula migrated 3-5 mm during the first 2 years, then became stable without further progression (28.6%). In six cases (30%) gross loosening and migration occurred, requiring revision to a larger cup. One case required exchange arthroplasty for infection (5%). All biopsies taken at the time of the revision for failure showed viable bone replacing allograft. If the criteria for success of major superior acetabular allografts include incorporation of the graft and long-term stability of the implant, then the success rate in this series is very low. Only 7 of 20 hips were successful over a relatively short time period. However, if expectations are lowered, and the procedure is considered successful if adequate bone stock is restored to the acetabulum to allow reconstruction with a cementless cup firmly fixed in viable bone, then all but three revisions were successful.     

Femoral head autograft in simultaneous primary and revision total hip arthroplasty

Bilateral total hip arthroplasty during one anesthetic procedure can be beneficial in properly selected patients. For patients who have a failed hip arthroplasty requiring revision and a contralateral arthritic hip requiring primary arthroplasty, bilateral surgery permits the resected femoral head from the primary procedure to be used as a fresh autogenous bone—graft during the revision procedure. Four patients underwent combined primary hip arthroplasty and contralateral revision hip arthroplasty during one anesthetic procedure. The femoral head obtained during the primary procedure was used as a structural acetabular bone—graft in three patients, and bone slurry was used to fill cavitary acetabular defects in one patient. A femoral neck autograft was used to reconstruct a calcar defect in one of the patients. After an average follow-up period of 27 months, all hips were functioning well with healed bone—grafts and stable prosthetic components.     

Acetabular revision using a total acetabular allograft

The most challenging aspect of an acetabular revision is the management of severe bone loss, which compromises implant fixation and stability. We present a case of failed acetabular revision with extensive bone loss (Paprosky Type 3b) in a 50-year-old woman with rheumatoid arthritis, which was treated using total acetabular allograft. At a follow-up of 1 year and 3 months, the allograft had united with the host bone. This is the first report of the use of a total acetabular allograft for revision total hip arthroplasty in India. The total acetabular allograft allows the placement of the component closer to the normal hip center, provides initial stability for the acetabular component, and restores bone stock to the host pelvis.     

Bone density adjacent to press-fit acetabular components. A prospective analysis with quantitative computed tomography

BACKGROUND: The status of periprosthetic bone stock is an important concern when revision total hip arthroplasty is undertaken. Remodeling of periprosthetic femoral bone after total hip arthroplasty has been studied extensively, and the phenomenon of femoral stress-shielding has been well characterized. Finite element analysis and computer-simulated remodeling theory have predicted that retroacetabular bone-mineral density decreases after total hip arthroplasty; however, remodeling of periprosthetic pelvic bone in this setting has yet to be well defined. This study was conducted to evaluate the short-term natural history of periacetabular bone-mineral density following primary total hip arthroplasty. METHODS: Periacetabular bone-mineral density was studied prospectively in a group of twenty-six patients who underwent primary hybrid total hip arthroplasty for the treatment of advanced osteoarthritis. Density within the central part of the ilium (directly cephalad to a press-fit acetabular component) was assessed with serial quantitative computed tomography. Baseline density was measured within the first five days following the total hip arthroplasty. Ipsilateral density measurements were repeated at an average of 1.28 years postoperatively. Density values at corresponding levels of the contralateral ilium were obtained at both time-points in all patients to serve as internal controls. RESULTS: Bone-mineral density decreased significantly (p< or =0.001) between the two time-points on the side of the operation. The mean absolute magnitude of the interval density reduction (75 mg/cc) was greatest immediately adjacent to the implant (p<0.001), but it was also significantly reduced (by 35 mg/cc) at a distance of 10 mm cephalad to the implant (p = 0.001). Relative declines in mean density ranged from 33% to 20% of the baseline values. No focal bone resorption (osteolysis) was detected at the time of this short-term follow-up study. With the numbers available, no significant interval alteration in bone-mineral density was found on the untreated (internal control) side (p> or =0.07). CONCLUSIONS: We suggest that the observed decline in bone-mineral density represents a remodeling response to an altered stress pattern within the pelvis that was induced by the presence of the acetabular implant. This finding corroborates the predictions of finite element analysis and computer-simulated remodeling theory. It remains to be seen whether this trend of atrophy of retroacetabular bone stock will continue with longer follow-up or will ultimately affect the long-term stability of press-fit acetabular components.     

颗粒骨打压植骨结合多孔非骨水泥臼杯在AAOSⅢ型髋臼大面积骨缺损翻修中的应用

背景：颗粒骨打压植骨是修复髋臼骨缺损的重要方法,对大面积髋臼骨缺损采用打压植骨结合非骨水泥臼杯重建仍然存在争议。目的：探讨同种异体颗粒骨打压植骨结合多孔非骨水泥臼杯髋臼重建术修复AAOSⅢ型髋臼大面积骨缺损的方法及近期疗效。方法：随访2005年6月至2010年4月收治的28例（28髋）AA0SⅢ型髋臼大面积骨缺损患者。男18例,女10例,年龄34-74岁,平均53．8岁。髋关节置换术后感染醐翻修9例,骨溶解及髋臼假体松动翻修19例。本组AAOSⅢ型髋臼骨缺损面积大,术中见髋臼骨缺损超过髋臼关节面的50％。全部采用同种异体颗粒骨打压植骨结合多孔非骨水泥臼杯髋臼重建术。术后定期随访,观察臼杯有无松动、植入骨与宿主骨整合情况,髋关节功能评分采用Harris评分。结果：28例均获得随访,术后随访时间为13-70个月,平均43个月。Harris评分由术前32-48分,平均41分,提高至末次随访时86-95分,平均90分。28例髋臼假体均固定牢固无松动征象,植入骨逐渐与宿主骨整合,无感染及坐骨神经损伤。结论：在获得臼杯初始稳定固定的情况下,大面积颗粒骨打压植骨（臼杯与宿主骨接触面积〈50％）结合多孔非骨水泥臼杯髋臼重建术修复AAOSⅢ型髋臼大面积骨缺损近期疗效较好,远期疗效尚待进一步随访。     

6 years follow-up of hip revision surgery

Revision total hip arthroplasty often presents surgeons with difficult bone loss problems. The purpose of this study was to evaluate the results of hip revision surgery according to bone stock We evaluated, in a retrospective study, 148 hip revision surgeries during 2004 to 2010. The Harris Hip Score (HHS), the acetabular cementation, the AAOS classification, the SOFCOT 99 bone loss grading and Barrack classification were used for clinical and radiological assessment. It can be observed significant improvement of HHS from a mean value of 45 preoperatively to 77.2 points postoperatively. Grade B acetabular cementation was observed in a significantly higher rate for situations that needed acetabular allograft reconstruction and where it cannot be performed because of allografts lack. Barrack grades C and D cementation were associated with 70% of SOFCOT 99 stage III and IV cases and only 5% of SOFCOT 99 stage 0-II cases.Using bone graft seems to be a reliable solution for restoring bone stock and stabilizing the cup in revision total hip arthroplasty with type II-IV acetabular defect according to the AAOS classification. Because SOFCOT 99 stages III-IV are often associated with poor cementation we prefer using uncemented distally fixed with screws revision stems for these cases.     

Acetabular reconstruction with bone impaction grafting and a cemented cup: 20 years' experience.

Acetabular bone stock loss compromises the outcome in primary and revision total hip arthroplasty. In 1979, a biologic method was introduced with tightly impacted cancellous allografts in combination with a cemented polyethylene cup for acetabular reconstruction. With this technique, it is possible to replace the loss of bone and to repair normal hip mechanics and hip function with a standard implant. Based on the authors' 20 years experience, a review of the long-term data is presented in primary total hip arthroplasty with preexisting acetabular bone stock loss, primary total hip arthroplasty in rheumatoid arthritis, patients who had bone impaction when younger than 50 years, and in acetabular revisions. The survival rate with revision of the cup for aseptic loosening as the end point was 94% at 10 to 17 years, 90% at 10 to 18 years, 91% at 10 to 17 years, and 92% at 10 to 15 years. From biopsy specimens from humans and histologic data in animal experiments the incorporation of these impacted bone chips was proven. The acetabular bone impaction technique using large morselized bone chips (range, 0.7-1 cm) and a cemented cup is a reliable technique with favorable long-term outcome.     

Bulk Femoral Head Autograft Without Decortication in Uncemented Total Hip Arthroplasty : Seven- to Ten-Year Results

Superolateral acetabular bone defect is a serious challenge in uncemented total hip arthroplasty for acetabular dysplasia. We report a bulk bone autografting technique without decortication of the acetabulum and femoral head contact surfaces in 22 joints. Mean follow-up time was 8.3 years, and survival rates were 100% for loosening and revision end points. The preoperative Japanese orthopedic association hip score increased from 49.5 to 94.0. Although trabecular bridging and graft remodeling occurred in all cases, complete trabecular reorientation was observed in only 15 joints. Eccentric polyethylene wear was observed in 8 of 22 joints, and osteolysis, in 1 joint. Our technique is easy to perform, and midterm results were favorable; thus, we conclude that it may be an effective option for bulk bone autografting.     

Revision total hip arthroplasty: analysis of the predictive value of a radiographic classification system for assessment of bone stock loss

AIM: The aim of this study was to evaluate the predictive value of a radiographic classification system concerning implant and bone graft in revision total hip arthroplasty. This classification is used to assess bone stock loss prior to surgery, thus hypothetically enabling an adequate choice of the implant and bone graft required. METHOD: 33 consecutive patients with the diagnosis of aseptic failure of total hip arthroplasty were included in the study. The investigation was performed using the classification system according to Saleh et al. The predictive value was analyzed by comparing the radiographically based recommendation concerning implant and bone graft and the intraoperative procedure according to a blinded observer technique. The Spearman coefficient of correlation (r (s)) was used to establish levels of agreement among multiple ordinal variables. RESULTS: Analysis of correlation between preoperative radiological estimations and intraoperative conclusions concerning implant and bone graft revealed coefficients of correlation (r (s)) of 0.53 (p < 0.01) for the acetabular and of 0.63 (p < 0.01) for the femoral classification. CONCLUSION: Our results indicate that the Saleh classification does not provide sufficient information for preoperative assessment of the revision implant and bone graft required concerning the acetabular side, whereas planning of the operative procedure regarding the femoral implant seems to be possible. These ambivalent findings should be taken into account prior to revision total hip arthroplasty.     

Bulk femoral head autograft without decortication in uncemented total hip arthroplasty: seven- to ten-year results

Superolateral acetabular bone defect is a serious challenge in uncemented total hip arthroplasty for acetabular dysplasia. We report a bulk bone autografting technique without decortication of the acetabulum and femoral head contact surfaces in 22 joints. Mean follow-up time was 8.3 years, and survival rates were 100% for loosening and revision end points. The preoperative Japanese orthopedic association hip score increased from 49.5 to 94.0. Although trabecular bridging and graft remodeling occurred in all cases, complete trabecular reorientation was observed in only 15 joints. Eccentric polyethylene wear was observed in 8 of 22 joints, and osteolysis, in 1 joint. Our technique is easy to perform, and midterm results were favorable; thus, we conclude that it may be an effective option for bulk bone autografting.     

Trabecular metal used for major bone loss in acetabular hip revision

The purpose of this study was to evaluate the outcome of trabecular metal (TM) acetabular components used in revision hip arthroplasty with major bone deficiency. We retrospectively reviewed the records of 46 patients undergoing revision hip arthroplasty with severe acetabular bone loss. Clinical outcomes were assessed using Harris Hip Score, Western Ontario and McMaster Universities, and Short-Form 12. Mean follow-up was 50 months. All patients had Paprosky type IIc or III acetabular bone deficiency. Major complications included 1 infection, 2 dislocations, and 1 arterial bleeding. Average Harris Hip Score was 78.2. Short-Form 12 scores were within population-based age-matched averages. Western Ontario and McMaster Universities scores were mainly in the 2 lowest disability categories. Porous tantalum shows promising results in revision arthroplasty with severe acetabular bone loss.     

异体骨移植在髋关节翻修术中应用的1O年随访

目的探讨异体骨移植在髋关节翻修术中应用的长期效果。方法自1997年6月至2000年12月,共进行15例15髋髋关节翻修术,得到随访13例13髋,男9例9髋,女4例4髋;左侧8髋,右侧5髋;平均年龄53岁（45-65岁）;初次置换术后至翻修时间4年8个月-11年9个月（平均9年2个月）;骨缺损情况：髋臼和股骨缺损均按AAOS分类,髋臼缺损Ⅰ型6髋,Ⅱ型5髋,Ⅲ型2髋;股骨缺损Ⅰ型5髋,Ⅱ型4髋,Ⅲ型3髋,无明显缺损1髋。手术采用髋关节后外侧切口,髋臼侧用髋臼锉打磨修整,将异体骨粒植入骨缺损区,打压塑形;2髋安放加大的生物型髋臼假体,11髋安上钛网杯或加强臼杯,螺钉固定后行骨水泥固定臼假体。股骨侧,假体应长于原假体的长度;尽可能保存股骨结构,以颗粒骨填入髓腔以获得重建;如缺损严重采用1-3块异体骨块放置于缺损区,骨块应长于缺损区2-3cm。术后1周,3个月,6个月,12个月,以后每年一次摄X片观察假体的变化。结果本组13例13髋随访时间10-12.5年（平均11年5个月）。Harris评分由翻修前43分（41-47分）提高至87分（85-89分）。影像学,2髋股骨柄假体术后两年出现垂直移位,1髋10mm,另1髋20mm,以后没有继续发展,11年后假体仍然稳定,无松动;宿主骨与颗粒骨的骨整合血管化,术后6个月出现并不断进行至2年左右完成,但宿主骨与块状骨的整合血管化时间要在5年以上,有5例在术后8年仍可辩认出骨块;2例在术后10年,1例在术后12年仍可清晰地辩认出部份骨块,而其余骨块己完全整合血管化。结论在髋关节翻修术中,应用同种异体骨修复骨缺损,为假体提供可靠的、充分的支撑,已成为必要的技术手段。骨的改建过程,视乎个体的特性,宿主骨的保有量,植入骨的多少等条件而定,一般在术后1-2年,部份患者超过10年。     

Arthroscopic treatment of cam-type femoroacetabular impingement: preliminary report at 2 years minimum follow-up

Femoroacetabular impingement is defined as anterior hip abutment between the acetabular rim and proximal femur. When it is secondary to acetabular overcoverage, it is pincer impingement. When it is secondary to femoral head and neck deformity, it is cam impingement. Open remodeling of impinging deformities is the standard treatment of this condition. We describe arthroscopic treatment of cam impingement in 19 patients using standard hip arthroscopy portals by the lateral approach. Sixteen patients improved their symptoms after the procedure; and 3 patients deteriorated, with 1 needing a total hip arthroplasty at 2 years follow-up. We had no cases with postoperative femoral neck fractures or avascular necrosis. Hip arthroscopy can be successfully used to treat cam impingement. The precautions used in open surgery to preserve femoral neck bone stock and hip vascularity should be followed.     

Displaced intracapsular hip fractures: hemiarthroplasty or total arthroplasty?

The role of total hip arthroplasty for the treatment of displaced intracapsular fractures of the proximal femur in active patients is controversial. Some authors have shown that such patients, when treated with a bipolar or unipolar hemiarthroplasty, are at increased risk of having acetabular erosion develop that might require later revision to a total hip replacement. In fact, the results of some authors were not substantially different from those reported for elective total hip arthroplasty and were better than results reported for hemiarthroplasty. However, other authors have strongly recommended avoiding total hip replacement in active elderly patients without preexisting acetabular disease (osteoarthritis, rheumatoid arthritis, Paget's disease). Although the current belief is that there is a place for primary total hip arthroplasty after intracapsular hip fracture, and that this procedure should be reserved for patients with preexisting symptomatic acetabular disease, in a preliminary prospective comparative study of 46 active patients without preexisting acetabular disease, the current author found better results with cemented Charnley's total hip arthroplasty than with cemented Thompson's hemiarthroplasty. Long-term outcome and more detailed indications for total hip replacement as the primary treatment for intracapsular displaced fractures of the proximal femur are topics for additional study.     

人工髋关节置换术后翻修术的临床分析

目的　对人工髋关节置换术后翻修的原因、治疗方法及疗效进行综合评价 ,以避免或减少翻修术的发生。方法　总结本院 1991～ 2 0 0 0年收治的人工髋关节置换术后翻修术病例 ,从翻修术的原因、治疗方法及疗效等方面进行系统的分析比较。结果　 10年间我院施行翻修术 98例。翻修术的原因以髋臼磨损为主 ,占 45 .92 %。其他依次为假体松动、感染、脱位、假体位置不良、柄远端股骨骨折和人工髋关节强直等 ,非假体松动原因而行翻修术 79例 ,占翻修病例总数的 80 .5 8%。 2次及以上翻修术的主要原因是习惯性脱位和感染。翻修术方式主要采用生物学固定。合并髋臼骨缺损 2 9例 ,股骨侧骨缺损 2 5例 ,自体或异体骨植骨修复骨缺损 2 5例。平均随访 63 .9个月 ,Harris评分翻修术后优良率 82 .2 8%。结论　翻修术的主要原因是髋臼磨损 ,多次翻修术的原因主要是假体习惯性脱位和感染。翻修术应以生物学固定为主。为避免或减少翻修术的发生和次数 ,在行初次人工关节置换术时 ,应严格掌握手术适应证 ,规范手术操作 ,减少术后并发症     

Cemented cup revisions

Among the several treatment techniques for acetabular reconstruction after total hip arthroplasty is cemented acetabular revision. Use of isolated cemented cup revision is not frequently chosen for acetabular revision, however, because outcomes with this technique are poor despite improved cementing techniques. Most cemented cup revisions are performed for severe bone loss when biologic fixation near the normal hip center is unlikely and are often supplemented with bone grafting and metal reinforcement devices cases. Advantages of using this technique are the ability to incorporate antibiotics into the cement and the ability to customize the cement mantle to host bone.