同种异体骨移植后的病理组织学观察

目的探讨同种异体骨移植后骨修复的生物学过程和病理组织学变化。方法收集自2002年2月-2004年3月因临床并发症取出的异体骨标本5例及因大段异体骨移植后不愈合再次植骨手术中活检病例2例，共7例。骨肿瘤4例，其中肱骨近端恶性纤维组织细胞瘤行肿瘤切除大段异体骨移植髓内钉内固定术1例，股骨干骨肉瘤行肿瘤段切除大段异体骨移植1例，股骨远端骨巨细胞瘤行肿瘤切除股骨远端大段异体骨移植钢板内固定术1例，胫骨近端巨细胞瘤行肿瘤切除大段异体骨移植钢板内固定术1例。创伤3例，其中2例为左股骨远端开放粉碎性骨折行大段异体骨移植骨不愈合切开取内固定植骨、外固定架固定术，同时对大段异体皮质骨取材活检；1例为胫骨中段开放性骨折，行钢板固定异体松质骨移植术，术后感染。结果通过观察骨吸收的病理组织学特点发现骨吸收主要集中在5例病例中，其临床特点可以归纳为：(1)X线片所示有严重的骨吸收，无伤口问题；(2)X线片显示有骨吸收伴有窦道、渗出；(3)伤口化脓。后者可以认为是骨组织的化脓性感染引起的骨吸收，前两种情况骨吸收可以分为：一是破骨细胞性骨吸收，常伴有新骨形成；二是炎症性骨吸收，吸收部位有较多的慢性炎性细胞，骨表面缺乏破骨细胞和成骨细胞，无新骨形成。3例有明显骨吸收者可以观察到血管内皮细胞增生、官腔闭塞。结论破骨细胞骨吸收是机体对异体骨修复和骨重建的过程。炎症性骨吸收的出现是异体骨移植中的不良组织学反应；如出现血管病变表示排斥反应重，异体骨移植可能失败。     

四肢恶性骨肿瘤功能重建后的并发症防治

目的分析四肢恶性骨肿瘤功能重建后并发症的发生原因与防治。方法自2002年9月至2004年12月共有22例患者接受保肢治疗。年龄10～63岁，平均26.3岁。男10例，女12例。其中骨肉瘤15例，恶性骨巨细胞瘤2例，软骨肉瘤5例。15例骨肉瘤患者术前均接受了2～3次化疗。待伤口愈合后再接受5～6次化疗。肿瘤部位：胫骨近端5例，股骨远端12例，股骨近端1例，股骨中段2例，肱骨近端2例。手术方法为局部肿瘤完整切除，大段异体骨移植术、人工假体重建术和肿瘤灭活再植术。其中10例行人工假体重建术，10例行大段异体骨移植术，2例行肿瘤灭活再植术。结果随访7～27个月，3例骨肉瘤患者术后局部复发，复发时间分别为术后3个月、7个月、1年，后行截肢术。1例患者术后3个月出现肺转移，经化疗后肺部肿块消失；2例大段异体骨移植术患者术后出现排斥反应，伤口不愈伴感染，后经清创、腓肠肌肌皮瓣转移术后愈合。1例人工假体重建术后2周，伤口出现渗液，后经局部换药后愈合。结论恶性骨肿瘤采取保肢的术后并发症与适应证的选择、肿瘤对化疗的敏感性、瘤体切除的方式、功能重建选择的方法等都有密切的关系。因此，在对恶性肿瘤采取保肢手术治疗时，必须综合考虑上述因素，才能减少并发症的发生。     

交锁翻修柄在股骨侧假体翻修术的应用

目的 报道采用交锁翻修柄(Bicontact和Kent)进行在全髋关节股骨侧假体翻修手术的疗效。方法 12例股骨侧假体翻修手术(假体松动5例，假体周围骨折7例)均采用现代无骨水泥技术，Bictintact翻修柄8例，Kent翻修假体4例，结合金属网、钢丝线缆握紧系统器械和异体骨移植进行结构重建。结果 平均随访8．40个月，功能优良10例(83．34％)，可1例(8．33％)，差1例(8．33％)，后出现Bicontact假体柄断裂和股骨干骨折。结论 在老年患股骨侧假体翻修术中，运用交锁翻修柄(Bicontact和Kent)能使手术时间和创伤减少，股骨侧固定快且牢固，并允许患早期进行功能锻炼；在股骨近端广泛骨缺失而需要大块异体骨移植进行重建的情况下，交锁翻修柄解决了既往各种假体较难固定于异体植骨块和残留的受体股骨中的问题。     

膝关节定制型肿瘤假体的翻修

目的通过对膝关节定制型肿瘤假体的翻修进行回顾性分析,总结手术技术和翻修原因,明确翻修术后并发症的发生,以及假体生存和功能情况。方法回顾性分析2002年6月-2007年6月收治的33例膝关节定制型肿瘤假体置换术后再次翻修患者的临床资料。其中男17例,女16例;年龄16～67岁,平均33.1岁。骨肉瘤17例,骨巨细胞瘤11例,骨恶性纤维组织细胞瘤2例,软骨肉瘤、滑膜肉瘤、脂肪肉瘤各1例。肿瘤部位:股骨远端22例,胫骨近端11例。翻修术与置换术间隔时间为6～180个月,平均45.3个月。翻修原因:肿瘤局部复发2例,假体周围感染8例,假体无菌性松动7例,创伤后假体周围骨折伴松动1例,假体柄折断6例,假体铰链机构失败9例。6例假体周围感染者,将原假体取出后行二期假体翻修;其余患者均行一期翻修。翻修假体均采用骨水泥固定假体,其中2例残留髓腔长度短于翻修假体柄,用异体骨段移植复合假体植入。结果17例两次手术均于同一医院进行的患者,首次置换手术时间为(149.8±40.5)min,翻修术为(189.9±43.8)min;置换术出血量为(605.2±308.0)mL,翻修术为(834.1±429.9)mL;以上指标比较差异均有统计学意义(P0.05)。患者术后均获随访,随访时间12～76个月,平均45.1个月。2例行异体骨移植者分别于术后1年半和2年达骨性愈合。3例于翻修术后12～24个月死于肺转移;3例发生肺转移,随访期间带瘤生存。术后30例存活患者9例出现并发症,发生率为30%;其中浅表感染2例,深部感染5例,机械性并发症2例。7例发生假体失败,失败率为23.3%。Kaplan-Meier生存曲线分析翻修假体5年生存率为68.6%。翻修术前患者肢体功能根据1993年美国骨肿瘤学会评分系统(MSTS93)评分为57.1%±10.6%,术后6个月为73.6%±14.4%,差异有统计学意义(P0.01)。结论膝关节定制型肿瘤假体的翻修主要原因是机械性问题和感染,翻修手术虽较复杂,具有一定并发症,但可保留大部分患者的肢体并恢复其功能。     

定制肿瘤型关节假体髓外柄断裂的有限翻修技术

 目的 介绍定制肿瘤型关节假体髓外柄断裂的有限翻修方法,并评价其临床应用效果。方法 3例患者行定制肿瘤型关节假体置换术后发生假体髓外柄断裂,男2例,女1例;年龄分别为25岁、51岁和52岁。原发肿瘤部位及病理组织学类型分别为股骨远端骨肉瘤、股骨远端复发性骨巨细胞瘤及股骨近端软骨肉瘤。假体髓外柄断裂分别发生于术后11个月、34个月和28个月,均无明显外伤史,为行走时发生假体断裂。假体断裂处位于股骨远端假体髓外柄结合部和股骨近端假体的股骨颈基底部。依据假体断裂后髓内柄固定牢固及髓外柄残留足够长度的情况,为避免常规翻修手术中较困难的原假体髓内柄及骨水泥取出,设计了股骨近端和远端翻修假体进行有限翻修,该翻修假体由套筒部和关节部组成,材质及关节部外形与原假体相同,翻修时保留原假体髓内柄,将翻修假体套接于残留的髓外柄,骨水泥及挤压螺钉固定,同时更换磨损的配件,从而完成有限翻修。术后常规功能锻炼,定期随访观察翻修假体稳定性及肢体功能恢复情况。结果 3例患者假体断裂原因为股骨远端假体髓外柄结合部、股骨近端假体股骨颈基底部疲劳断裂各1例,股骨远端假体髓外柄结合部松动、锁钉断裂1例。翻修术后分别随访1个月、103个月和110个月,1例骨巨细胞瘤患者发生软组织内肿瘤复发而再行肿瘤切除术。至末次随访时,3例患者翻修假体固定牢固、无松动。MSTS评分肢体功能评分分别为66.7%、86.7%和83.3%。结论 定制肿瘤型关节假体由于疲劳或结构失效可发生断裂,套接式翻修假体可保留固定牢固的原假体髓内柄而行有限翻修,降低了手术难度,有利于肢体功能的尽快恢复。     

骨肿瘤初次保肢手术后生物性重建失败的肿瘤假体翻修术

目的评估骨肿瘤初次保肢手术后生物性重建失败的肿瘤假体翻修的疗效。方法2004至2006年，13例骨肉瘤和3例骨巨细胞瘤患者在香港威尔斯亲王医院接受手术治疗。15例患者应用同种异体骨重建，另1例患者应用带血管腓骨移植重建骨缺损。应用肿瘤型假体进行翻修手术的重建。翻修术后患者膝关节活动范围良好时，订制的可延长假体接受延长手术。结果患者平均年龄23．2岁（13～43岁），平均随诊26．4个月（6～47个月）。翻修手术的原因包括：7例患者出现同种异体骨骨折或软骨下骨塌陷，5例患者骨不愈合，3例患者异体骨感染，1例患者膝关节僵硬。翻修手术的假体包括10例患者应用订制型假体，其他患者应用组合式假体。翻修手术的部位包括9例股骨远端假体，6例胫骨近端假体和1例股骨中段假体。订制假体中6例是可延长假体，假体的延长方式中5例是微创延长、1例无创延长。翻修手术后，膝关节活动改善，平均从18．1°（0°-90°）至91．9°（50°-120°）。下肢缩短不等长畸形从平均5cm（2-11．5cm）纠正至平均1．5cm（0-4cm）。翻修术后患肢功能MSTS评分从34．6％改善到89．2％。翻修术后2例患者出现部分皮肤坏死，1例患者出现腓总神经麻痹，以后部分恢复，1例患者出现胫骨裂纹骨折；没有感染和植入物失败。结论保肢手术后生物学重建失败所引起下肢缩短和僵硬，应用人工假体翻修是可行的，早期效果令人鼓舞。膝关节僵硬患者可获得良好的关节活动度。严重的下肢缩短畸形通过可伸长假体逐渐获得纠正。     

远端固定型假体结合同种异体骨移植在髋关节股骨翻修中的应用

[目的]探讨应用远端固定生物型假体结合同种异体骨移植进行髋关节股骨侧翻修的临床效果。[方法]2008年7月~2014年5月,行非感染性假体松动股骨侧翻修11例(骨水泥假体10例,非骨水泥假体1例)。所有患者采用远端固定生物型假体结合股骨近端同种异体颗粒骨打压植骨,其中7例同时应用同种异体皮质骨支撑植骨。男4例,女7例;平均年龄65.3岁(48~79岁);左侧7例,右侧4例。初次置换原因:股骨头无菌性坏死6例,股骨颈骨折3例,骨性关节炎2例。翻修距原手术时间平均12.8年(3~21年)。依据Paprosky分型,Ⅱ型4例,ⅢA型4例,ⅢB型3例。临床功能评价采用Harris评分。翻修用假体:Restoration(Stryker)3髋,MP(Link)8髋。[结果]所有患者均获得随访,随防时间12~75个月,平均29个月。1例术后出现切口渗液,15d后愈合;1例术后6年并发假体周围螺旋形骨折(Vancouver分型B1),假体未松动,行切开复位内固定术。随访期内X线片显示移植骨均愈合良好,假体稳固,周围未见透亮带及松动、下沉征象;术前6例双下肢不等长患者均得到矫正(长度差1 cm);无感染、脱位及深静脉血栓形成等并发症;无假体再翻修病例。Harris评分从术前的平均(30.3±7.2)分提高到最后评估时的平均(82.4±5.9)分,Harris评分优良率为81.8%。[结论]在伴有广泛骨质缺失的股骨翻修中,远端固定生物型假体是较好的选择。术中采用股骨近端颗粒骨打压植骨重建干骺端骨缺损,并在股骨干部皮质薄弱或缺损时结合同种异体皮质骨支撑植骨,可使假体柄远近段均获得较好的初始稳定性,且中短期临床效果满意,远期疗效尚有待观察。     

原位微波灭活瘤段＋重建治疗骨巨细胞瘤的临床观察

目的应用微波原位灭活瘤段＋重建技术治疗骨巨细胞瘤,观察临床疗效和肢体功能。方法 2004年3月至2011年4月本组共应用此方法治疗32例骨巨细胞瘤患者,其中骨盆1例,股骨远端12例,胫骨近端10例,桡骨远端4例,肱骨近端3例,肱骨远端1例,跟骨1例。病理分级：Ⅰ级4例,Ⅱ级11例,Ⅲ级17例。术中边缘外分离肿瘤,原位插入微波针,控制性高温灭活瘤体,自体骨粒或骨水泥填充病灶腔隙,填充骨水泥和异体骨混合物,部分需行内固定,观察术后肿瘤复发和肢体功能评分。结果 32例患者皆得到随访,平均随访2年8个月。发现1例复发,1例感染,肢体关节功能评定：好者28例,可者4例,差者0例。结论原位微波灭活瘤段＋重建技术治疗骨巨细胞瘤可能降低了骨巨细胞瘤术后的复发,并保留较好的肢体功能。     

股骨肿瘤瘤段切除后修复重建的体会

目的总结股骨肿瘤切除后修复重建的经验教训。方法手术治疗16例股骨肿瘤患者,9例股骨近端肿瘤患者中7例采用瘤段切除＋假体重建,2例股骨转子部肿瘤应用瘤段切除＋Gamma钉＋骨水泥固定;4例股骨干肿瘤采用瘤段切除＋带锁髓内钉＋骨水泥重建;3例股骨远端肿瘤采用瘤段切除＋膝关节假体置换。结果 16例获随访,时间1年2个月～13年。按Enneking肢体肌肉骨骼肿瘤外科治疗重建术后功能评估标准进行评估：4～5分12例,3分3例,1分1例。结论严格掌握适应证、无瘤无菌操作、彻底灭活肿瘤截骨端是降低复发率的关键。有效的组织修复和功能重建不但可以保留股骨骨肿瘤切除后的肢体,而且具有良好的功能。     

大段同种异体骨修复骨肿瘤手术后缺损研究进展

大段同种异体骨移植重建肢体功能已成为骨肿瘤保肢手术的重要方法。根据肿瘤类型确定手术切除边界,在保证肿瘤完整切除的前提下重建患肢功能,术中辅以坚强的内固定对大段同种异体骨移植后骨愈合至关重要。大段同种异体骨移植的骨愈合机制主要为激活骨诱导及骨传导,体现在受体逐渐爬行替代异体骨的缓慢过程。异体骨缓慢愈合过程中感染、异体骨骨折及骨不愈合等并发症发生率较高,影响了大段同种异体骨移植治疗的效果。该文就骨肿瘤保肢手术中大段同种异体骨移植手术方法、并发症防治方面的研究进展作一综述。     

Limb-salvage surgery in the treatment of osteosarcoma in skeletally immature individuals

Sacrifice of major growth plates during resection and fixed-length reconstruction of a limb in a skeletally immature child with osteosarcoma may result in a significant limb-length inequality as growth progresses. A limb-length discrepancy in the humerus may cause minor cosmetic problems but does not generally result in a significant functional deficit. In the lower extremity, tumors about the knee, including the distal femur and proximal tibia, usually present the dilemma of whether limb salvage by arthrodesis, osteoarticular allograft, or endoprosthetic replacement would result in a significant limb-length inequality and whether amputation of the extremity is a preferable procedure. The techniques of rotationplasty and an expandable endoprosthesis have been successfully used for treating skeletally immature patients with osteosarcoma of the distal femur. With regard to survival and function, the results obtained with these innovative methods are favorable compared with those of a high above-knee amputation.     

151 endoprosthetic reconstructions for patients with primary tumors involving bone

As part of the UCLA limb salvage program, 151 patients received 151 endoprostheses for primary tumors involving bone. Follow-up of all patients was to death (56), revision (21), or a minimum two years for the 74 additional survivors (range: 24-114 months; mean: 52 months). Endoprosthetic replacements were of the distal femur (81), proximal femur (19), proximal humerus (13), proximal tibia (11), scapula (11), total femur (8), total humerus (4), intercalary prostheses (2), and one each of the distal humerus and the pelvis. There were three soft tissue sarcomas, five benign bone lesions, and 143 primary malignant tumors of bone. MSTS function was good-excellent in 78%. There were 64 local complications in 55 patients (36%). Mechanical failure occurred in 24 patients (15.9%), local recurrence occurred in ten (6.6%), minor wound healing problems in nine (5.9%), and infection in eight (5.3%). Few systemic complications were reported. Function appeared to be location dependent. All of the 29 patients with benign or low grade malignant tumors (parosteal, IA, IB) have survived. Of the 116 patients with stage IIA and IIB disease, 59% survived three years, and a Kaplan-Meier analysis projects that 56% are expected to survive at five years. Only 17 (11%) of these 151 endoprostheses have been revised; an additional four (3%) eventually came to amputation. The Kaplan-Meier analysis revealed that 91% of the prostheses survived three years and 83% survived five years. The Cox Proportional Hazards model revealed that for patients with stage IIA and IIB disease, the risk of death is four times the risk of the need for revision at five years. Although endoprosthetic reconstructions have their own unique complications, they have proven durable in this series of patients. Local problems usually can be managed without amputation, and patient satisfaction is high.     

Survivorship analysis of 141 modular metallic endoprostheses at early followup

Although our institution historically has been known for its use of osteoarticular allografts in limb salvage surgery for tumors, during the last 8 years there has been an increase in the use of metallic modular endoprostheses. A retrospective review of 141 patients in whom a modular endoprosthesis was implanted in the past 8 years was done, and survival data were compiled using Kaplan-Meier survival analysis, clinical score was determined using a previously described system, and a multivariate regression analysis was done to identify independent risk factors. There were 13 failures (defined as need for revision of the majority of the prosthetic components, excluding cases of local recurrence) yielding an overall implant survival of 91%. Based on Kaplan-Meier estimates, the endoprosthetic survival rate was 88% at 3 years and 76% at 5 years; per location, it was 100% for the proximal humerus, 100% for the proximal femur, 87% for modular knees, and 53% for total femoral implants at 3 years. The clinical scores were good to excellent in 74% of the patients. Multivariate analysis showed that only location and infection were independent risk factors for prosthesis failure. Loosening, infection, and dislocation were independently predictive of a fair or poor clinical score. Age, gender, diagnosis, length of implant, dislocation, nor failed prior allograft had an independent effect on implant survival or clinical outcome. The proximal humeral and proximal femoral implants had greater survival rates than modular knee and total femoral implants. Conversion of failed allografts to modular endoprostheses had a trend for a higher failure rate, but after a multivariate analysis, did not prove to be an independent risk factor for failure. We think that our experience is similar to other endoprosthesis survivorship reports in the literature with short-term followup.     

Limb salvage surgery for primary bone sarcoma of the lower extremities: Long-term consequences of endoprosthetic reconstructions

Background: Adjuvant chemotherapy and endoprosthetic replacement for bone sarcomas of the lower extremity is well established. The specific long-term consequences of these endoprosthetic reconstructions for the patient's affected limb are unknown. Method: The oncologic results and the survival of the endoprostheses were reviewed in 32 patients with primary bone sarcoma of the femur or proximal tibia. There were 26 high-grade sarcomas, and 6 low-grade sarcomas. A proximal femoral endoprosthesis was used for reconstruction in 4 patients, a total or push-through femoral endoprosthesis in 11 patients, a distal femoral endoprosthesis in 15 patients, and a proximal tibial endoprosthesis in two patients. Results: Median survival was 10 years (range, 1.1 to 18.9 years) for patients with high-grade sarcoma, and 8.1 years (range, 7.1 to 10 years) for patients with low-grade sarcomas. Distant metastases developed in seven patients (22%), all with stage IIB sarcoma, with concomitant local recurrence in 3 patients (9%). Five-year overall and disease-free survival rates for high-grade sarcomas were 81% and 73%, respectively. The overall endoprosthetic survival rate was 87% at 5 years, 80% at 10 years, and 56% at 15 years. Median follow-up of the original endoprostheses was 8.3 years (range, 0.6 to 18.7 years). Endoprosthesis-related complications occurred in 13 patients (41%); most complications were mechanical failures. The highest complication rate was found in distal femoral replacements (60%); amputation was necessary in both patients treated with a proximal tibial endoprosthesis. Five endoprostheses (16%) were revised. An amputation of the involved limb was performed in four patients (13%): in two patients because of local recurrence and in the other two patients because of infection. For patients alive at follow-up, the median functional Enneking evaluation score was 22 points (range, 12 to 28 points), with the highest functional scores in patients with a distal femoral endoprosthesis, and the lowest functional scores in patients with total or push-through femoral replacements. Conclusion: Endoprosthetic reconstructions gave satisfying functional results in most patients after long-term survival. However, the proximal tibial and distal femoral endoprosthesis are particularly at risk for long-term endoprosthetic complications requiring additional surgical procedures.Presented at the Ninth International Symposium of the International Society of Limb Salvage (ISOLS), New York, September 11, 1997.     

肱骨近端恶性肿瘤的保肢治疗

目的 探讨肱骨近端恶性肿瘤切除术后的重建方法。方法 36例肱骨近端恶性肿瘤,其中骨肉瘤 11例、软骨肉瘤 6例、皮质旁骨肉瘤及纤维肉瘤各 3例、原始神经外胚层瘤及恶性纤维组织细胞瘤各 2例、转移性骨肿瘤 5例、恶性骨巨细胞瘤 4例。骨肉瘤、原始神经外胚层瘤与恶性纤维组织细胞瘤患者均接受了新辅助化疗。肿瘤关节内切除 33例,关节外切除 3例。 21例采用异体半关节移植, 4例采用人工假体置换, 6例行游离锁骨移植, 5例行带骨膜血管蒂锁骨移植。结果 随访 6～ 118个月,平均 62.7个月。死亡 11例,局部复发 3例。按 Enneking功能评价标准, 21例采用异体半关节移植的患者,平均得分 24分; 4例人工假体置换的患者,平均得分 26分; 11例采用同侧锁骨重建肱骨近端的患者,平均得分 23分。结论 肱骨近端恶性肿瘤保肢手术的重建以人工假体置换和异体半关节移植为首选,儿童的保肢可选用同侧锁骨移植。保肢术后的功能与肩袖和肩外展肌的修复密切相关。     

恶性骨肿瘤保肢手术后的骨关节返修术

目的 分析四肢恶性骨肿瘤保肢手术后进行返修术的原因及手术治疗经验。方法 1994年1月－1997年12月进行保肢手术后骨关节返修术8例,平均无瘤生存时间8年。主要返修原因是严重的创伤性骨关节炎、骨折、骨吸收。影响返修手术的主要困难是软组织挛缩和肢体短缩。结果 行全髋返修1例,股骨下端长段同种异体骨移植再建3例,在原移植物基础上行全膝关节置换3例,更换髓内钉1例。术前骨扫描结果提示原移植的4例长段同种异体骨已有较活跃的骨代谢,术后病理学检查显示移植骨段存活。术后疼痛症状明显改善,功能满意。结论 保肢手术后的返修术主要原因是植入的异体骨或灭活瘤段发生骨折、关节功能较差。在有良好的软组织覆盖下,应用绞链式可旋转全膝关节假体或长段异体骨复合半限制球轴式表面置换人工膝关节假体可获得较理想的术后功能。     

Pelvic reconstruction with a free vascularized distal femur for revision total hip arthroplasty

The reconstruction of massive structural acetabular defects after revision arthroplasty presents a unique challenge to the orthopedic surgeon. This report describes such a salvage procedure where an autologous vascularized distal femur was used to reconstruct acetabular bone stock with subsequent implantation of a total femoral endoprosthetic replacement that uses a constrained cup and a hinged total knee system. At 2 years of follow-up, there is a good functional result with full incorporation of the graft.     

Intramedullary, antibiotic-loaded cemented, massive allografts for skeletal reconstruction 26 cases compared with 19 uncemented allografts

We compared the outcomes of 26 intramedullary cemented massive allografts with 19 allografts without cementation; all allografts were used for reconstruction after excision of bone sarcomas. In the cementation group, 12 allografts were used as osteochondral grafts (proximal humerus 4, proximal tibia 4, and distal femur 4), 7 as intercalary diaphyseal allografts of the femur, and 7 for a knee arthrodesis. In the uncemented allografts, 3 allografts were used as osteochondral grafts (proximal humerus 2, proximal tibia 1), 2 as intercalary diaphyseal allograft of the femur, and 14 for a knee arthrodesis. The average length of follow-up was 40 (25-60) months. 14 of 26 cemented allografts had an excellent (osteotomy line: not visible) or good (fusion 75% of the cortical thickness) healing of the junction site. Infection developed in 1 allograft. Fracture occurred in 4 of 12 cemented osteochondral allografts due to a subchondral collapse (all in the proximal tibia). Fractures at the junction site in the lower extremity developed in 4 of 22 cemented allografts. In 19 allografts without cementation, 11 had excellent or good healing of the junction. Late infection developed in 4 allografts, fracture of the allograft in 3 cases, and junction fracture in 3 of 17 patients with reconstruction of the lower extremity. Intramedullary graft cementation seems to reduce the fracture and infection rates.     

What Is the Survival of the Telescope Allograft Technique to Augment a Short Proximal Femur Segment in Children After Resection and Distal Femur Endoprosthesis Reconstruction for a Bone Sarcoma?

BackgroundLarge, malignant bone tumors and revision limb salvage procedures often result in the resection of extensive lengths of the involved bone segment, leaving a residual segment of bone that may be too short to support a standard intramedullary stem for endoprosthetic reconstruction. Telescope allografting, in which an allograft is used to augment the remaining bone segment by telescoping it into the residual bone segment, was described for situations in which residual bone stock is insufficient after tumor resection or prosthetic revision. Apart from one study that first described the procedure [15], there are no other studies reporting the outcome of this telescopic concept for restoring bone stock.Questions/purposesFor patients younger than 18 years who underwent the telescopic allograft technique to augment a short segment of the proximal femur after resection of bone sarcomas who also underwent endoprosthesis reconstruction of the distal femur, we asked: (1) What is the survivorship free from removal of the telescopic allograft and the endoprosthetic stem at 7 years after surgery? (2) What proportion of these reconstructions will heal to the host bone without delayed union or nonunion? (3) What is the functional outcome based on the Musculoskeletal Tumor Society (MSTS) score?MethodsWe retrospectively studied our institutional database and identified 127 patients younger than 18 years who underwent surgery for a primary malignant bone tumor of the distal femur between December 2008 and October 2018. After excluding 16 patients undergoing amputation and rotationplasty and 57 patients undergoing recycled autograft/allograft reconstruction, 54 patients who underwent primary or revision distal femur endoprosthesis reconstruction were identified. Among these patients, we considered 15 patients who underwent telescopic allograft augmentation of the femur for analysis. One patient was lost to follow-up before 2 years but was not known to have died, leaving 14 for analysis at a median (range) 49 months (24 to 136 months) of follow-up. The indications for telescopic allograft augmentation of the femur in our institution were a proximal femur length of less than 120 mm after resection or resection of more than two-thirds of the total length of the femur. Ten of 14 patients underwent telescopic allograft augmentation as a revision procedure (distal femur resorption in five patients, endoprosthesis stem loosening in three patients, implant fracture in one patient, and infection in one patient), and the remaining four patients underwent telescopic allograft augmentation as a primary limb salvage procedure for large malignant bone tumors of the distal femur. The histologic diagnosis in all patients was osteosarcoma. At the time of telescopic allograft augmentation and reconstruction, the median age of the patients was 14 years (7 to 18 years). The size and the type of bone allograft to be used (femoral shaft or proximal femur) was planned before surgery, with consideration of the extent of resection, level of osteotomy, diameter of the host bone at the osteotomy site, and approximate diameter of the endoprosthesis stem to be used. The segment of the cylindrical allograft used for telescoping was thoroughly washed, prepared, and impacted onto the native femur to achieve telescoping and overlap. Serial digital radiographs were performed once a month for the first 6 months after the procedure, every 2 months until 1 year, and then every 6 months thereafter. Two surgeons in the department (at least one of which was involved in the surgery) retrieved and reviewed clinical notes and radiographs to determine the status of the telescopic allograft and endoprosthesis stem. We defined delayed union as radiological union at the osteotomy site more than 6 months after the procedure without additional surgery; we defined nonunion as no radiological evidence of callus formation at the osteotomy site 9 months after the procedure, necessitating additional surgery. The reviewers did not disagree about the definition of healing time. None of the patients missed radiographic follow-up. Kaplan-Meier survivorship free from removal of telescopic allograft and the endoprosthesis stem at 7 years after surgery was estimated. Patient function was assessed using the 1993 version of the MSTS [9], as determined by chart review of the institutional database performed by one of the surgeons from the department.ResultsThe survivorship free from removal of the telescopic allograft and endoprosthesis stem at 7 years after surgery was 80% (95% confidence interval 22% to 96%). The allograft united with the host bone in 100% (14 of 14) of the patients. Though 21% (3 of 14) had delayed union, no nonunions were seen. The median (range) MSTS score at the final follow-up interval was 27 (22 to 30).ConclusionAlthough this is a small group of patients, we believe that allograft segments help augment short bone stock of the proximal femur after long-segment resections, and the telescopic technique seems to be associated with a low proportion of nonunion or delayed union, which is one of the most common complications of allografts. Maintaining an adequate length of the proximal femur is important in preserving the hip, and this technique may be especially useful for young individuals who may undergo repeated revision procedures.Level of EvidenceLevel IV, therapeutic study.     

Survivorship and clinical outcome of modular endoprosthetic reconstruction for neoplastic disease of the lower limb

We reviewed retrospectively the results in 211 consecutive patients who had undergone limb salvage for bone neoplasia with endoprosthetic reconstruction of the proximal femur (96), distal femur (78), proximal tibia (30) and total femur (7). Their mean age was 50 years (11 to 86) and the mean follow-up period was 37.3 months (1 to 204). A total of 35 (16.6%) prostheses failed. Overall, implant survival was 78% (95% confidence interval (CI) 0.29 to 0.54) at five years, 60% (95% CI 0.93 to 2.35) at ten years and 60% (95% CI 1.27 to 3.88) at 15 years. Survivorship of the limb was 97.6% (95% CI 1.73 to 3.35) at ten years. The gender, age, diagnosis and location of the tumour were not prognostic variables for failure. Modular endoprosthetic replacement in the lower limb is a durable long-term reconstructive option, with the implants generally outlasting the patient.