Revision of anterior cruciate ligament reconstruction with allografts in patients younger than 40 years old: a 2 to 4 year results

Purpose

The purpose of this study is first to report the outcomes, at 4 years follow-up, in revision ACL surgery using allografts in patients younger than 40 years old, and then compared soft tissue allografts to bone tendon allografts.

Methods

This retrospective study included 47 patients who underwent ACL revision surgery with fresh-frozen allografts. Patellar tendon allograft or tibialis anterior allograft was used. Twenty-seven patients undergoing ACL revision with patellar tendon allograft were compared retrospectively with twenty-two patients undergoing the same procedure with soft tissue tibialis anterior allograft. Lysholm, IKDC, and KT-1000 values were obtained preoperatively and postoperatively.

Results

The average patient follow-up was 4.6 years (±2.5). The mean age at time of the revision was 34 years old (±6.3). Overall, patients reported the overall condition of their knee as excellent or good in 85 % of the patients (10 excellent, 33 good). Based on their experience, 85 % would have the surgery again if they had the same problem in the other knee. Both subgroups experienced significant improvement in Lysholm, IKDC, and KT-1000 values, with no difference found between groups at final follow-up.

Conclusion

Revision ACL with allografts has excellent and good results in 85 % of patients younger than 40 years old. No statistical difference was seen between soft tissue (tibialis anterior) and patellar tendon allograft.

Level of evidence

IV.     

Long-term results of tendon allografts for anterior cruciate ligament replacement in revision surgery and in cases of combined complex injuries

We assessed the long-term validity of anterior cruciate ligament (ACL) reconstruction using tendon allografts. Nineteen patients were followed up for 8 years (mean 94 months) after tendon allograft replacement for ACL rupture. The evaluation used the International Knee Documentation Committee (IKDC) grades, the Lysholm score, and the Tegner scale. Two patients sustained a rerupture after a serious injury. Two others scored poorly because of associated proximal ipsilateral tibial and other fractures (IKDC grade D). Nine patients scored nearly normal (grade B) and six abnormal (grade C). The Lysholm score showed nine excellent (average 98), five good (average 87), and one fair result (70). Two of the excellent-rated patients were IKDC grade C solely because the X-rays showed a slight (1-mm) narrowing of the medial cartilage. One patient had 0.5-mm narrowing. The X-ray findings may indeed indicate future problems. On the Tegner scale the sports level decreased by an average of 2.1 points (from 6.87 to 4.73), and by 0.8 point compared to the level at which the patient had wished to perform. ACL repair using tendon allografts appears to provide satisfactory results on the Lysholm and Tegner scales. The IKDC scoring suggests future cartilage degeneration. Its value for knees with multiple ligament lesions and for revision cases is demonstrated. Only two reruptures were noted, suggesting good reliability of allografts on the long term. Received: 10 July 1998 Accepted: 12 June 1999     

异体皮质骨板在股骨假体周围骨折中的应用

目的研究异体皮质骨板在股骨假体周围骨折中的作用。方法回顾性分析2002年10月-2006年7月使用异体皮质骨板治疗的股骨假体周围骨折患者22例,其中术中骨折18例,术后骨折4例。采用Vancouver分型方法对骨折进行分类,其中A型4例,B型13例,C型5例。所有骨折均采用非骨水泥柄加异体皮质骨板支撑固定,异体皮质骨板以钢丝和(或)捆绑带与股骨固定。采用Harris评分对术后效果进行评价。结果所有患者均获随访,随访时间8~45个月,平均27.5个月,术后平均Harris评分89分。术后12~24周22例患者中21例愈合,平均愈合时间16.5周。1例患者于术后17周发生移植骨板骨折。最后一次随访时X线片均证实移植物与宿主骨整合。1例患者术后患肢疼痛,3例同侧膝关节僵直。结论异体皮质骨板是治疗股骨假体周围骨折的有效手段,能够作为生物接骨板提供机械稳定性和生物稳定性。短期随访发现使用皮质骨板有较高的骨折愈合率并能增加骨量。异体皮质骨板应在股骨假体周围骨折中常规应用。     

髋关节置换术后股骨假体周围Vancouver B型骨折的治疗

目的研究全髋关节置换术后股骨假体周围VancouverB型骨折的治疗效果。方法股骨假体柄周围骨折10例，其中Vancouver分类B1型3例，B2型2例，B3型5例。B1型骨折行切开复位，异体皮质骨板移植加钢丝环扎治疗；B2型骨折行切开复位，钢丝或线缆固定，加长股骨柄翻修；B3型骨折行切开复位，加长股骨柄翻修，异体皮质骨板移植加钢丝环扎固定。全部患者均得到随访，时间8～36个月，平均27个月，采用Harris髋关节功能评分和X线片对治疗结果进行评价。骨折愈合，患肢恢复行走功能为治疗成功，而骨折未愈合、假体松动、发生感染等并发症需要再次手术治疗者为治疗失败。结果10例患者骨折全部愈合，假体无松动、感染等并发症，治疗成功率100％。9例患者自由行走，1例需要助行器帮助。最后一次随访，Harris评分平均为83分。移植骨板与宿主骨骨性愈合，股骨皮质厚度增加3～5mm。结论假体稳定性和局部骨骼条件是影响VancouverB型骨折治疗效果的重要因素，针对髋关节置换术后假体柄周围VancouverB型骨折不同亚型采用不同的治疗方法能够取得很好的疗效。同种异体皮质骨板移植重建股骨假体周围骨折，不但能提供固定支撑作用，而且可促进骨折愈合，增加局部骨量和改善骨强度，显示出较好的优越性。     

Imaging of vascularized fibula autograft placed inside a massive allograft in reconstruction of lower limb bone tumors

OBJECTIVE: Bone allografts and vascularized fibula autografts were combined (the fibula inside the massive allograft) for skeletal reconstruction in a homogeneous group of patients. To verify the biologic behavior of the grafts, we followed the series using conventional radiography and CT analysis. MATERIALS AND METHODS: Twenty-four patients with bone tumors had intercalary segments of tibia or femur reconstructed and were followed up for 36-120 months. Sequential radiographs and CT scans were analyzed. RESULTS: Three types of behavior were observed. In 13 patients, the allograft maintained its architecture without fracture, although a regular enlargement of the inlaid fibula led to progressive integration with the allograft. A dense line on allograft endosteum was the first sign of bone bridges heralding fusion of the two grafts. In eight patients, fracture or nonunion of the allograft occurred, and the autograft reacted with rapid appearance of dense hypertrophy that again induced bridges to the allograft. In three patients, no changes in autograft size and density were followed by fracture with no callus formation. This behavior was interpreted as unsuccessful vascularization of the autograft. CONCLUSION: Sequential radiography and CT analysis enabled us to understand the changes in a combined graft offering an original way to revascularize bone allografts.     

Sterilization of bone allografts by microwave and gamma radiation

Abstract

Purpose: Bone allografts are used to enhance healing in osteotomies, arthrodesis, fractures and to replace bone loss resulting from tumour or trauma. However, a major concern associated with the bone allografts is the potential for disease transmission. Various sterilization techniques have been developed to prevent infection through allografts. This study was undertaken with the aim of exploring the use of microwave radiation for sterilization of bone allografts and to compare with gamma radiation sterilization.

Materials and methods: Bone allografts were processed from femoral heads obtained from living donors. The effect of microwave and gamma radiation on the bacteria isolated from bone allograft was evaluated. The microwave radiation treatment was performed at 2450 MHz (frequency) for varying lengths of time at maximum power 900 Watts (W). Viability of three Gram-positive bacteria – Bacillus subtilis, Corynebacterium, Staphylococcus aureus and three Gram-negative bacteria – Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was examined after irradiation of bacterial suspensions and contaminated processed bone allografts. The sterility test of microwave and gamma irradiated bone allograft was carried out in accordance with ISO (International Organization for Standardization) 11737-2.

Results: Microwave irradiation (2450 MHz and 900 W) of bacterial isolates resulted in complete inactivation within 60 seconds. The contaminated bone samples showed no growth of organisms after 2 minutes of exposure to microwave irradiation. No viable counts were detected in bone grafts inoculated with Gram-negative bacterial species on gamma irradiation to a dose of 15 kGy. Bones contaminated with Gram-positive bacteria required a higher dose of 20 kGy for complete inactivation.

Conclusions: The study shows that sterilization of contaminated femoral head bone allografts can be achieved by short exposure of 2 min to 2450 MHz and 900 W microwave radiation.     

Complication rate and diagnostic yield of 515 consecutive ultrasound-guided biopsies of renal allografts and native kidneys using a 14-gauge Biopty gun

Our objective was to evaluate the safety and diagnostic efficacy of the ultrasound-guided renal biopsy procedure using an automated biopsy device (Biopty gun) with a 14-gauge needle. Five hundred fifteen consecutive ultrasound-guided renal biopsies performed in two large university hospitals were retrospectively reviewed. Three hundred forty-five biopsies were performed on renal allografts and 170 on native kidneys. The tissue specimen was adequate for histological evaluation in 95.3% of the cases (94.8% in the transplanted kidney group, 96.5% in the native kidney group). The overall complication rate was 12.2% and was significantly higher in the native kidney group (19.4%) than in the renal allograft group (8.7%). Major complications occurred in 2.7% of the cases (2.9% of the renal allografts and 2.4% of the native kidney biopsies), including one procedure-related death and the loss of the renal allograft in two other patients. Minor complications were noted in 9.5% of the biopsies and there were significantly more in the group of the native kidneys (17.1%) than in the group of the transplanted kidneys (5.8%). Renal biopsy with an automated device using a 14-gauge needle has a high tissue recovery rate, but it is associated with a small risk of serious complications. Electronic Publication     

S-MRI score: A simple method for assessing bone marrow involvement in Gaucher disease

Semi quantitative MRI is a very useful procedure for evaluating the bone marrow burden (BMB) in Gaucher disease (GD). Score systems have been applied to obtain a parameter for evaluating the severity of bone disease. Our purpose was to test a simple, reproducible and accurate score to evaluate bone marrow involvement in GD patients. MRI was performed in spine, pelvis and femora at diagnosis in 54 adult GD1 patients, 61.1% of whom were female. Three MRI patterns and punctuation in each location were defined: normal, 0; non-homogeneous infiltration subtypes reticular, 1; mottled, 2; diffuse, 3; and homogeneous infiltration, 4. This score was called Spanish-MRI (S-MRI). Two independent observers applied the S-MRI and bone marrow burden score and compared the differences using the non-parametric Mann-Whitney test. Correlation rank test was calculated. In 46 patients (85.2%), bone involvement was observed. Thirty-nine (72.3%) had their spine affected, 35 (64.8%) pelvis and 33 (61.2%) femora. Fourteen patients had bone infarcts, 14 avascular necrosis, 2 vertebral fractures and 2 bone crises. Correlation analysis between S-MRI and BMB was (r(2)=.675; p=.0001). No evidence of correlation was observed between CT activity and S-MRI nor between CT activity and BMB. We have found a relationship between genotype and bone infiltration according to S-MRI site and complications. S-MRI is a simple method that provides useful information to evaluate bone infiltration and detect silent complications. Our results correlated with the BMB score but offer higher sensitivity, specificity and accuracy for classifying the extent of bone disease.     

Giant cell tumor of bone: radiographic changes following local excision and allograft replacement

The authors retrospectively evaluated the clinical records and radiographs obtained from 41 patients who had giant cell tumor of bone and who were treated by local resection and allograft replacement. Postoperative complications developed in 41% of the patients. However, the eventual clinical outcome was considered to be satisfactory in 85% of all cases. There were no instances of tumor recurrence, and surprisingly, postoperative arthritis was not a major problem. The major complications encountered were infection and allograft fracture; bone infection accounted for most of the clinical failures. All infections were associated with the increasing soft-tissue swelling and bone resorption detected on radiographic studies. Other radiographic parameters that were associated with an increased rate of complications included osteopenia, increased periosteal reaction, and decreased bone formation at the host-donor junction site. The clinical outcome was distinctly less favorable in those cases in which the patient had had a pathologic fracture or a previous resection, or in whom the graft was implanted at the distal radius.     

清创后Ⅰ期植骨治疗慢性骨髓炎的远期疗效

目的 探讨清创后Ⅰ期植骨治疗慢性骨髓炎的远期效果.方法 1999年3月-2003年5月,79例(28例骨不连)慢性骨髓炎患者接受清创后Ⅰ期自体、同种异体或混合骨移植治疗.随访时间60～111个月,平均77个月.结果 79例患者中,6例(8%)患者感染复发,其中自体骨移植2例,异体骨移植3例,混合骨移植1例.三种植骨方法感染复发率差异无统计学意义.28例骨不连患者,27例(96%)感染治愈并获得骨愈合,其中自体骨移植(23例)和异体骨移植(2例)均获得骨愈合,无感染复发;混合骨移植3例,2例骨愈合,1例感染复发伴骨不连.结论 清创后Ⅰ期骨移植治疗慢性骨髓炎可以获得90%以上的感染治愈率及骨愈合率,感染复发多在术后1年内,远期疗效稳定.     

High-resolution CT of temporal bone trauma

Computed tomographic (CT) findings in 18 patients with temporal bone trauma were reviewed. Eight patients suffered longitudinal fractures of the petrous bone, which were associated with ossicular dislocation in two patients. Transverse fractures were detected in six patients, with a contralateral mastoid fracture in one patient. In four patients, the fractures were restricted to the mastoid region. Of the 14 patients in whom adequate neurologic evaluation was available, seven had a permanent facial nerve or hearing deficit while five suffered at least a transient neurologic deficit related to the temporal bone trauma. Routine head CT (10 mm sections) demonstrated only eight of 19 petrous bone injuries. Clues to such injury included opacification of the mastoid air cells (10 patients), sphenoid sinus (11 patients), external canal and middle ear air space (10 patients), and local pneumocephalus (five patients). Evidence of brain trauma or extraaxial hematoma was seen in 12 patients. In 13 cases, high-resolution CT was also performed, demonstrating temporal bone injuries in all. This latter technique allows rapid and detailed evaluation of temporal bone trauma. Reports of radiographic evaluation of temporal bone trauma tend to deal with a somewhat skewed population, selected on the basis of clinical symptomatology. In a major trauma center equipped with high-resolution CT, it was found that temporal bone fractures may be seen incidentally, or in patients in whom symptomatology related to temporal fracture is obscured by much more serious neurologic compromise.     

I期后路全脊椎切除治疗重度胸腰椎畸形的神经系统并发症

目的 探讨应用I期后路全脊椎切除治疗重度胸腰椎畸形的神经系统并发症,并分析相关危险因素.方法 2000年2月-2010年9月接受I期后路全脊椎切除治疗的重度胸腰椎畸形患者67例,男29例,女38例;年龄14～62岁,平均31.4岁.其中青少年(年龄<18岁)21例,成人(年龄≥18岁)46例.侧凸畸形11例,平均冠状面主弯Cobb角90.4°;侧后凸畸形25例,冠状面主弯Cobb角94.5°,后凸角度平均65.5°;角状后凸畸形28例,平均后凸角74.3°;圆弧状后凸3例,平均后凸角91.1°.初次手术患者59例,翻修患者8例.采用主弯区顶椎全脊椎切除,全节段椎弓根螺钉内固定矫形和360°植骨融合术,统计神经系统并发症的发生情况.结果 平均随访时间14个月(3～69个月),出现神经系统并发症者共8例(11.9%),其中严重神经并发症3例,发生率4.5%,包括1例大量失血血容量灌注不足导致完全性脊髓损伤.轻度神经并发症患者5例,发牛率7.5%.胸椎全脊椎切除的神经损伤发生率要明显高于腰椎(P<0.05).多个椎体切除的并发症发牛率显著增加(P<0.05).术前已经伴有或者不伴有神经损害表现患者的神经并发症发生率分别为33.3%和7.3%(P<0.05),翻修手术的并发症发生率明显增加(P<0.05).差异虽无统计学意义(P>0.05),但出现神经系统并发症的8例患者术前均合并有严重的后凸畸形(>60.).结论 I期后路全脊椎切除是外科治疗重度胸腰椎畸形有效手术方式,但神经并发症应引起关注.相关神经损伤危险因素包括术中操作不当、大量失血、术前已经有神经受损表现、胸段截骨、多个椎体切除、翻修手术和严重后凸.

Abstract：

Objective To analyze the neurological complications in treatment of severe thoracolumbar spinal deformity with one stage posterior vertebral column resection (pVCR) and discuss the related risk factors. Methods There were 67 patients with severe thoracolumbar spinal deformity who underwent one-stage pVCR from February 2000 to September 2010.There were 29 males and 38 females at an average age of 31.4 years old(range,14-62 years).There were 21 patients at age less than 18 years old and 46 at age more than 18 years old.Patients were divided into four pathological types:severe scoliosis group(n=11,mean Cobb angle 90.4°),kyphoscoliosis group(n=25,mean scoliosis 94.5°,and mean kyphosis 65.5°),angular kyphosis group(n=28,mean kyphosis 74.3°)and global kyphosis group(n=3,mean kyphosis 91.1°).of all the patients,59 patients underwent primary surgery and eight underwent revision surgery.Surgical methods included posterior apex vertebral column resection,segemental pedicle screw fixation and correction as well as 360° bone fusion.Neurological complication was statistically analyzed. Results The average follow-up was 14 months (range,3-69 months),which showed severe neurologic complication in eight patients(11.9%)after surgery.Severe neurologic complication occurred in three patients (4.5%),among whom one patient presented delayed complete paraplegia 23 hours after surgery.Five patients had mild neurologic deficits(7.5%),the incidence of which was higher than 23.1%for thoracic osteotomy (P<0.05).Multilevel pVCR had high rate of neurological complications (P<0.05).The incidence rate was 33.3% for patients with preoperative neurologic compromise and 7.3%for patients mthom preoperative neuroiogic compromise (P<0.05).The incidence rate was increased in the revision surgery (P<0.05).Eight patients with neurological deficits had kyphotic angle of raore than 60°although there was no statistical difference (P>0.05). Conclusions pVCR is an effective surgical method for the correction of severe thoracolumbar spinal deformity.The neurological complications,however,should be paid attention to the surgeons.The risk factors for neurologic complications include improper manipulation,massive blood losing,preoperative neurologic compromise,osteotomy at thoracic rein,multi-level vertebrectomy,revision surgery and severe kyphosis.     

动力髁螺钉在股骨转子周围骨折治疗中的应用

目的 通过观察动力髁螺钉(DCS)在股骨转子周围骨折治疗中的应用和疗效,探讨DCS治疗股骨转子周围骨折的固定原理、可行性、优越性及相关注意事项. 方法 回顾性分析自2000年1月至2006年12月应用DCS治疗股骨转子周围骨折23例,其中老年患者10例,均有不同程度的内科并存症;青壮年13例,均系交通伤等高能量损伤.按Boyd分型:Ⅰ型1例,Ⅱ型5例,Ⅲ型9例,Ⅳ型8例.术前进行详细体检及针对性治疗后.用DCS固定转子周围骨折. 结果 术后经平均18个月随访,无死亡患者.早期并发症3例,其中肺部感染2例,泌尿系统感染1例,均经治疗痊愈.1例远期并发症,为创伤性关节炎.23例均达骨性愈合.按Harris评分标准,优良率达96%,无一例发生断钉、骨不连、髋内翻及下肢缩短外旋畸形等并发症. 结论 DCS治疗股骨转子周围骨折操作简单,符合生物力学特点,固定牢固可靠,是治疗股骨转子周围骨折的理想方法 之一,尤其适用于转子下骨折、反转子骨折、骨折累及大转子梨状窝和转子下外侧皮质骨粉碎的骨折.     

Radiographic evaluation of joints resurfaced with osteochondral shell allografts

The radiographic features of 41 cadaveric osteochondral shell (low ratio of subchondral bone to articular cartilage) allografts placed in 24 patients for articular resurfacing as an alternative to arthroplasty are presented. Underlying causes of joint disease included ischemic necrosis (20 grafts), osteochondritis dissecans (nine), chondromalacia patellae (10), and posttraumatic osteochondral fracture with degenerative disease (two). Congruity with the adjacent native articular surface and the opposite side of the joint was evident on immediate postoperative radiographs in all patients, and proved to be critical to the ultimate success of the procedure. On follow-up radiographs over a period of 2-28 months, successful incorporation of the allograft was characterized by progressive loss of the relative increased density of the graft, in association with diminished lucency related to new bone formation at the graft-native bone interface, as well as maintained alignment. Graft failure was associated with positional changes including collapse, persistent increased density, and poorly defined fragmentation that occasionally simulated infection radiographically and resulted in intraarticular bodies. Resurfacing of diseased articulations with osteochondral shell allografts constitutes a potentially desirable alternative to total joint arthroplasty, particularly among younger patients. Consequently, an awareness of the expected radiographic alterations associated with graft incorporation and failure is important.     

Allografts in the treatment of anterior cruciate ligament injuries

Symptomatic knee instability is a common complaint among athletic individuals after a torn anterior cruciate ligament (ACL) of the knee. Allograft ACL reconstruction has gained popularity for primary and revision reconstructions. This graft choice has become popular with good intermediate term results combined with decreased operative times, hospital costs, and improved immediate postoperative pain and function. Intermediate follow-up has demonstrated similar results with autograft reconstructions, without the addition of donor site morbidity. Multiple allograft options exist for ACL reconstruction. The most commonly selected grafts include patellar tendon, Achilles tendon, and tibialis allografts. The use of a tibialis allograft provides a stout graft for reconstruction, while minimizing bone tunnel size. Bone-patella-bone allografts provide bone to bone fixation options with flexibility in tunnel selection sizing.     

Management of post-biopsy renal allograft arteriovenous fistulas with selective arterial embolization: immediate and long-term outcomes

AIM: To evaluate the outcomes after transcatheter embolization of percutaneous biopsy-related arteriovenous fistulas in renal allografts. MATERIALS AND METHODS: All post-biopsy renal-transplant vascular injuries referred for embolization between June 1999 and October 2006 were reviewed retrospectively. There were six male and six female patients with a mean age of 49.8 years (range 25-67 years); nine patients were symptomatic, three asymptomatic. Colour Doppler ultrasound (CDUS) and angiography showed one intra-renal arteriovenous fistula in 10 patients and two in two patients, combined with a pseudoaneurysm in six patients. Superselective embolization using a single catheter or coaxial microcatheter was performed with 0.035' coils or 0.018'microcoils, respectively, in all 12 cases. 24-h creatinine clearance values before (the day of biopsy) and after (7-14 days; 3 months) the procedure were compared using the Wilcoxon signed-rank test. Physical examination and CDUS were performed after 1, 6, and 12 months, and yearly thereafter. Mean follow-up was 33.6 months. RESULTS: Complete definitive occlusion of the fistula was achieved consistently with a single procedure. No procedure-related complications occurred. Renal infarction was minor in all patients (0-10% in nine and 10-20% in three). Symptoms resolved completely. Creatinine clearance values obtained before and after embolization were not statistically different (p=0.168;.889 respectively). No late recurrences were reported. CONCLUSION: Transcatheter embolization with coaxial or single-catheter techniques was effective and safe for treating post-biopsy arteriovenous fistulas in renal transplants. The loss of renal parenchyma was minimal and no mid-term deterioration of allograft function was noted. The long-term survival of the renal allograft seemed to be not affected by embolization.     

颈椎单侧关节突交锁的治疗选择

目的 探讨颈椎单侧关节突交锁的不同治疗方法选择.方法 32例颈椎单侧关节突交锁,行头颅牵引复位成功8例,其中3例维持牵引1个月后改行头颈胸石膏固定,余5例行前路减压植骨融合内固定术.23例牵引失败,其中14例行前路切开复位、椎间盘切除植骨融合内固定术;3例前路复位失败行椎间盘切除加椎体次全切除减压植骨内固定术,1例前路复位失败改行后路切开复位后再前方植骨内固定术;3例行后路切开复位侧块内固定植骨融合术,2例行后路切开复位减压、前路椎间盘切除减压植骨内固定术.1例由于漏诊,伤后8个月行前路减压植骨融合术.结果 平均随访18个月.发现颈椎不稳2例,均为仅行牵引复位,未做融合术者.颈前路手术者植骨块术后12周均获骨性融合.颈椎生理曲度及椎间隙高度恢复较好.无内固定并发症,亦无治疗中神经并发症.结论 下颈椎单侧关节突交锁的治疗需要综合考虑多方面的因素,包括是否伴有椎间盘损伤、是否合并后柱骨折、脊髓压迫及损伤情况.对伴有创伤性颈椎间盘突出的单侧关节突交锁者,前路减压复位稳定术是首选方法,对于不伴椎间盘突出者,可试行牵引复位或直接后路切开复位固定.     

Cement coating of osteoarticular allografts in rats to prevent the immune response

Recently, more attention is being paid to the treatment of the articular surface defect in the young, active individual. Resurfacing or "shell" allografts are being considered as one of the alternatives for treatment. The immune response by the host may be the chief obstacle to the successful use of fresh osteoarticular allografts. Since proteins on the surfaces of allograft bone cells are considered to be the principal antigens eliciting the immune response, we hypothesized that mechanical masking of these cells by a biodegradeable blocking agent might prevent the immune response. Osteoarticular allografts of the distal femur were performed in rats and the cut surfaces of the graft were coated with cement before implantation. In a preliminary experiment, six biodegradeable cement materials were tried (bone wax, zinc polycarboxylate, collodion, fibrin adhesive, zinc oxide, and isobutyl-cyanoacrylate). Of these, the zinc oxide cement and isobutyl-cyanoacrylate were effective in inhibiting the immune response observed in control rat distal femur allografts. A second experiment was performed using nine rats with zinc oxide and nine rats with isobutyl-cyanoacrylate cements. These were compared with 20 control rats that had allografts without cement coating. Eighteen of the control rats (90%) developed an immune response, while only 22% (2/9) of the rats with zinc oxide coating and 33% (3/9) of the rats with isobutylcyanoacrylate developed an immune response. In a third experiment distal femur allografts were performed in 13 rats using only the liquid component of the zinc oxide cement.(ABSTRACT TRUNCATED AT 250 WORDS)     

The radiology of total hip replacement

The radiology of total hip replacement (THR) and its complications is reviewed in conjunction with a long-term follow-up study on 402 patients with 501 prostheses. The indications, contraindications, biomechanics, and operative management of these patients is discussed. Clinical complications such as deep vein thrombosis, pulmonary embolism, and hemorrhage are mentioned. Postoperative infections including granulomatous pseudotumors, dislocations and fractures, true loosening of the prosthesis, and heterotopic bone formation (HBF) are discussed and illustrated. The importance of differentiating the lucent line from true loosening is stressed. Mechanical and other clinical complications which are largely ignored by radiologists are also discussed. The uses of arthrography and bone scanning are included.