Initial fixation strength of a new hybrid technique for femoral ACL graft fixation: the bone wedge technique

Background Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation. Hypothesis A hybrid fixation technique (extracortical and aperture fixation) with undersized interference screw placed behind a bone wedge provides a higher fixation strength as aperture fixation with a screw alone matching the size of the tunnel. Study design Experimental laboratory study. Methods We evaluated the initial fixation strength (single cycle and cyclic loading tests) of hybrid and interference screw aperture fixation using different sized interference screws in porcine knees. Results Analysis of yield load, maximum load and stiffness in the single cycle loading test showed no statistically significant differences for hybrid fixation with a 1 mm undersized screw and aperture fixation with a screw matching the size of the tunnel. The use of an undersized screw alone resulted in low fixation strength. Conclusion The initial fixation strength of the hybrid technique with undersized screws is comparable to that of interference screw fixation matching the size. Clinical relevance The new “bone wedge fixation” is an alternative for ACL graft fixation without the risk of graft laceration and graft rotation.     

ACL reconstruction by bone-patellar tendon-bone graft: mechanical evaluation of the elastic modulus and failure modes

The aim of this study was to apply an engineering approach to study the biomechanical behaviour of both native and reconstructed anterior cruciate ligaments (ACL) under tensile test, simulating the primary stability of the reconstructed ACL in the immediate postoperative period, when the bone callus has not formed yet. We used the bovine bone-patellar tendon-bone grafts to reconstruct ACL in bovine knees. The grafts were fixed by means of titanium interference screws and titanium transverse compressive screws. We tested 18 native and 18 reconstructed ligaments (7 with interference screws and 11 with transverse compressive screws). We applied mechanical tension at a 500 mm/min strain rate, and observed the mode of failure. The data analysis confirmed the different behaviour recorded in load elongation curves, a difference enhanced in stress-strain curves for both fixation methods. The stress-strain patterns for the interference screw and for the native ligament were quite similar.     

Primary stability with tibial press-fit fixation of patellar ligament graft: An experimental study in ovine knees

Purpose: To investigate the initial fixation strength and to assess the value of tibial press-fit fixation of the bone-tendon-bone graft in anterior cruciate ligament reconstruction. Type of Study: Nonrandomized control trial. Methods: For tibial press-fit fixation, the tibial bone block of the bone-tendon-bone graft is countersunk in a bony groove at the distal tunnel outlet and fixed over a bone bridge with 2 No. 6 Ethibond sutures. The bone cylinder harvested from the tibial tunnel using an oscillating hollow saw is plugged into the tibial tunnel parallel to the graft, thus providing for additional anchoring of the graft by tibial press-fit fixation. In a comparative experimental study in 46 ovine knees, this fixation method was assessed for its value in anterior cruciate ligament reconstruction. A tibial bone tunnel was placed in routine manner in each ovine tibia using a target drill unit and an oscillating hollow saw. The complete patellar ligament, proximally attached to the patella and distally to a cylindrical bone block (20 × 8.4 mm), served as graft. Tibial fixation in group A (n = 10) was done using a titanium interference screw (20 × 8 mm), in group B (n = 10) using a titanium staple, in group C (n = 12) using suture fixation over a bone bridge, and in group D (n = 14) using the press-fit fixation described above. In a materials testing machine, all specimens were subjected to continuously increasing load until failure at a velocity of 1 mm/second. Ultimate failure load, stiffness, stress-strain characteristics, and failure mode were evaluated. Results: Ultimate load to failure was 572 N (range, 473 to 680 N) in group A, corresponding to a fixation stiffness of 17.68 N/mm. For group B, ultimate load to failure was 608.4 N (range, 511 to 727 N) and stiffness of 19.92 N/mm. Bone block dislocation was the failure mode in groups A and B. Group C with exclusive suture fixation showed an ultimate load to failure of 304.5 N (range, 120 to 327 N) and a stiffness of only 6.96 N/mm. The mode of failure was suture cutout caused by the bone block in 9 of the cases and untying of the suture knot in 3 cases. Group D with press-fit fixation showed a significantly higher primary stability of 758 N (range, 513 to 993 N) relative to group C, with a corresponding stiffness of 25.12 N/mm (P < .02). In this group, the mode of failure was ligamentous rupture from the bone block. Regarding mechanical properties, no significant differences were seen between groups A, B, and D. Conclusions: Tibial press-fit fixation allows for metal-free fixation with high primary stability. By refilling the bone tunnel, the ligament (with a rather small cross-sectional diameter compared with hamstrings) is safely fixed within the bone tunnel to prevent potential postoperative tunnel enlargement due to movement of the graft within the tunnel. Anchoring the graft at the entrance into the joint, it provides for reduced graft length and adequate elasticity and accomplishes the requirements of fixation at the correct anatomic insertion site.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 9 (November-December), 2001: pp 963–970     

Femoral press-fit fixation versus interference screw fixation in anterior cruciate ligament reconstruction with bone-patellar tendon-bone autograft: 20-year follow-up

Introduction

The aim of this paper is to present our experience with femoral press-fit fixation in anterior cruciate ligament reconstruction using bone-patellar tendon-bone autograft.

How four and twelve weeks of implantation affect the strength and stiffness of a tendon graft securely fixed in a bone tunnel: a study of Evolgate fixation in an extra-articular model ovine model

Healing of a tendon graft to a bone tunnel is slower than the healing of a bone plug. Therefore, the device chosen for hamstring fixation may need to maintain its strength and stiffness longer than the device chosen for bone-tendon-bone fixation. We evaluated, in an extraarticular ovine model, how 4 and 12 weeks of implantation affect the strength of a tendon graft fixed to bone with the Evolgate. The long digital extensor tendon was transplanted and fixed with the Evolgate into a 30-mm long, 8 mm diameter bone tunnel drilled in the tibial metaphysis of both posterior limbs of 15 skeletally mature Suffolk sheep. Immediately after implantation, and 4 and 12 weeks later, biomechanical cyclic load tests in 50 N increments were performed until failure to evaluate the ultimate failure load (UFL). Histological analysis was also performed at 4 and 12 weeks. Biomechanical tests revealed a UFL of 339±120 N at time 0, and increases to 635±19 N (4 weeks) and to 867±80 N (12 weeks). The differences between all 3 groups were significant (p<0.001, paired t test). The histological evaluation showed a layer of cellular, fibrous tissue between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganized during the healing process. The collagen fibers that attached the tendon to the bone resembled Sharpey’s fibers. The strength of the interface significantly and progressively increased between weeks 4 and 12 after transplantation, and was associated with a degree of bone ingrowth noted histologically. The use of the Evolgate seems not to interfere with the bone ingrowth after implantation, allowing an improvement in strength of the bonetendon- device complex.     

Effects of reinforcement with the iliotibial tract flap in ACL reconstruction using bone-patellar tendon-bone

Introduction We attempted to reinforce the transplanted ligament by wrapping it with the iliotibial tract (ITT) flap to get more volume and to protect the graft from impingement in the intercondylar space postoperatively in reconstruction of the anterior cruciate ligament (ACL) using bone-patellar tendon-bone (BTB), and investigated the results in comparison with those of BTB alone.Materials and methods The study included 88 cases (88 knees). Group A comprised 43 knees with the reinforcement and group B 45 knees with BTB alone. Both groups were evaluated by second-look arthroscopy, magnetic resonance imaging (MRI), manual testing, International Knee Documentation Committee (IKDC) score, and histopathological evaluation more than 2 years after the reconstruction.Results In the second-look arthroscopic findings, 84% of the reconstructed ACL in group A had good appearance, and no fibrous split was observed. The ratio of fibrous disorder was significantly less in group A in comparison with group B (p=0.0037). Distinct reduction of the tension of the reconstructed ligament was observed in 9% of group A and 36% of group B (p=0.0088). Regarding the results of the Lachman test, the ratio of the negative group was higher in group A (p=0.0067). In the MRI findings fulfilled pictures to the inside of the reconstructed ligament were observed in 77% of the patients photographed in group A. In contrast, the fibrous split was observed in 55% in group B.Conclusions Reinforcement by wrapping with the ITT flap for the BTB autograft was effective in ACL reconstruction. The ratio of fibrous disorder and reduction of tension in the reconstructed ligament decreased.     

Femoral bridge stability in double-bundle ACL reconstruction: impact of bridge width and different fixation techniques on the structural properties of the graft/femur complex

Background  The aim of this study was to evaluate the impact of different widths of the bony bridge between the femoral AM and PL bundle tunnel and different fixation techniques on the structural properties of the graft/femur complex in double-bundle ACL reconstructions. Hypothesis  Double-bundle ACL reconstruction with a bony bridge between AM and PL bundle tunnel of 1 mm results in significantly lower structural properties of the graft/femur complex when compared to a bridge of 2 and 3 mm. Interference screw fixation significantly lowers the structural properties when compared to cortical fixation. Study design  Controlled laboratory study. Methods  Double-bundle ACL reconstructions using different bridge widths (1 mm, 2 mm, and 3 mm bridge) were loaded to failure after a cyclic loading protocol (1,000 cycles 0–200 N) and the structural properties were compared to a single-bundle ACL reconstruction group (n = 10 in each group). The structural properties of using a cortical button fixation were then compared to interference screw fixation (2 mm bridge). Statistical analyses were performed using a Mann–Whitney test (P < 0.05). Results  Double-bundle reconstructions with cortical button fixation (1, 2, and 3 mm bridge) showed significantly higher ultimate failure loads and stiffness and significantly lower elongation compared to single-bundle reconstructions. Double-bundle ACL reconstructions with a 1 mm bridge showed significantly reduced structural properties of the graft/femur complex compared to a 2 or 3 mm bridge. Aperture fixation led to significantly lower ultimate loads when compared to cortical fixation. Conclusion  The bony bridge between the two femoral tunnels in double-bundle ACL reconstructions influences the stability of the graft/femur complex. Aperture fixation using interference screws shows inferior results when compared to cortical fixation. Clinical relevance  The results suggest that the indication for anatomical ACL reconstruction may include the size of the lateral femoral condyle. In small knees, a second femoral tunnel may be difficult to locate with a minimum bridge width of 2 mm.     

锁定加压钢板内固定联合植骨治疗Barton骨折

目的 探讨应用锁定加压接骨板(LCP)联合支撑植骨治疗Bartoll骨折的临床疗效.方法 2002年6月-2008年1月,对30例Barton骨折患者,采用切开复位支撑植骨LCP内固定法治疗.术后早期进行合适的康复锻炼.结果 术后30例均获得3-24个月的随访,平均12个月.术后X线片显示骨折全部愈合.掌倾角6°～16°,平均10.4°;尺偏角17°～25°,平均20.1°.桡骨纵向无短缩.采用腕关节功能及X线片测量指标进行综合评定:优20例,良8例,差2例;优良率达93.3%.结论 应用锁定加压钢板内固定联合支撑植骨治疗Banon骨折,能最大限度地恢复桡骨与尺骨的相对长度、掌倾角及尺偏角,关节面平整.术后配合合理的康复锻炼,能使腕关节功能达到最大的恢复.     

髓内植骨单臂外固定架固定治疗前臂骨折骨不连

骨不连是前臂骨折的并发症之一,治疗方法较多,有时疗效并不令人十分满意.自1994～1999年应用髓内植骨单臂外固定架固定治疗前臂骨折骨不连14例,骨不连全部愈合,前臂功能恢复良好.     

寰椎椎板钩联合枢椎椎弓根螺钉内固定的力学稳定性评价

目的 评价寰椎椎板钩联合枢椎椎弓根螺钉内固定的生物力学稳定性.方法 取6具新鲜尸体颈椎标本置于1.5 N·m载荷下,测量C_(1-2)节段的三维运动范围(ROM).标本按随机顺序,依次行完整状态(完整状态组)、不稳状态(齿状突周围韧带切除,为不稳状态组)、经寰枢关节间隙螺钉联合Gallic内固定(固定A组)、寰椎椎板钩联合枢椎椎弓根螺钉内固定(固定B组)、寰枢椎椎弓根螺钉内固定(固定C组)5种状态下的三维ROM值测量.比较各组标本的屈伸、侧屈、旋转ROM值.结果 完整状态组、不稳状态组、固定A、B、C组的平均屈伸ROM值分别为17.78°、30.69°、2.25°、2.93°、2.73°,组间比较差异有统计学意义(F=216.69,P=0.000);平均侧屈ROM值分别为9.56°、17.18°、1.91°、2.30°、2.05°,组间比较差异有统计学意义(F=122.75,P=0.000);平均旋转ROM值分别为44.19°、57.30°、1.22°、2.88°、2.07°,组间比较差异有统计学意义(F=154.54,P=0.000).固定A、B、C组较完整状态组和不稳状态组各个方向的ROM值均明显减少,差异均有统计学意义(P<0.05),但固定A、B、C组之间符个方向的ROM值比较差异均无统计学意义(P>0.05).结论 寰椎椎板钩联合枢椎椎弓根螺钉内固定可提供与经寰枢关节间隙螺钉联合Gallic内固定和寰枢椎椎弓根螺钉内固定相当的力学稳定性.在以上两种方法无法实施时,可作为一种安全的替代.     

Technique of split skin graft fixation using hypafix: a 15-year review

The technique of graft fixation with Hypafix was introduced in 1986 and has since been adapted for use in all sites to become the standard technique in the management of paediatric burns at the Women's and Children's Hospital Burn Unit. The technique is versatile, safe, simple, reliable and inexpensive, and has proven to be effective in over 700 burn patients, with 18 patients (2%) requiring repeat grafts. The patient's care is continued in a designated Burn Scar Assessment Clinic with a range of 'contact media', including Hypafix, Elastofix, silicone gel and Elastomer products, being applied as necessary.     

Internal fixation of congenital pseudarthrosis of the tibia with plate and bone graft

Surgical Principles Stable internal fixation of the tibial fragments with correct axial alignment using a one-third tubular plate, a semitubular plate or a dynamic compression plate depending on the age of the patient and size and thickness of the tibial fragments. The plate is placed against one side of the tibia and fixed with screws to an autogenous corticocancellous bone graft which has been inserted on the opposite side of the same tibia. A strong autogenous bone graft from the contralateral tibia or the ipsilateral femur is essential because the screws necessary to keep the plate in place cannot be firmly anchored in the atrophic fragments alone. The thickened, fibrous periosteum tightly bound to the fragments around the pseudarthrosis must be resected. Autogenous bone grafts from the iliac crest or from the site of removal of the autogenous corticocancellous graft are added as well. First published in: Operat. Orthop. Traumatol. 1 (1989), 237–253 (German Edition).     

排钉内固定结合植骨治疗胫骨平台骨折的疗效分析

目的:探讨排钉内固定结合植骨治疗胫骨平台骨折的临床疗效。方法:回顾性分析2012年5月至2014年5月收治且获得随访的36例胫骨平台骨折患者的临床资料,男25例,女11例;年龄17～65岁,平均43.5岁。受伤至手术时间3～10 d,平均5.8 d.所有患者采用L形或T形骨板排状螺钉内固定结合植骨方法治疗。末次随访时按照美国特种外科医院膝关节功能评分法评定疗效。测量比较患者术后3 d与术后1年的胫骨平台内翻角、后倾角及股胫角。结果:36例患者的手术时间平均(2.2±0.6) h,术中出血量平均(310.5±36.2) ml,住院时间平均(14.8±2.7) d.36例患者术后获随访,时间12～30个月,平均18.2个月。骨折愈合时间4～8个月,平均6.2个月。36例患者术后3 d 与术后1年的胫骨平台内翻角、后倾角及股胫角比较差异无统计学意义。末次随访时按照美国特种外科医院膝关节功能评分法评定疗效:优18例,良13例,中4例,差1例。结论:采用排钉内固定结合植骨治疗胫骨平台骨折可有效预防关节面二次塌陷,达到解剖复位、坚强固定及早期进行功能锻炼的目的,效果满意。     

Effects of hyperbaric oxygen treatment on tendon graft and tendon-bone integration in bone tunnel: biochemical and histological analysis in rabbits.

Despite moderate success in clinical applications, outcome of tendon grafts employed for anterior cruciate ligament (ACL) reconstruction remains unsatisfactory. This study investigated the effects of hyperbaric oxygen (HBO) on neovascularization at the tendon-bone junction, collagen fibers of the tendon graft, and the tendon graft-bony interface incorporated into the osseous tunnel in rabbits. Forty rabbits were assigned to two groups. The HBO group was exposed to 100% oxygen at 2.5 atmospheres pressure for 2 h daily, 5 consecutive days in a week. The control group was maintained in cages exposed to normal air. Histological studies of 12 rabbits were performed postoperatively at 6, 12, and 18 weeks. Biomechanical studies of 24 rabbits were conducted postoperatively at 12 and 18 weeks. Electron microscopy (EM) analyses of four rabbits were performed postoperatively at 18 weeks. Experimental results demonstrated that a higher number of Sharpey's fibers bridged the newly formed fibrocartilage and graft in the HBO group than in the control group. In addition, HBO treatment increased neovascularization and enhanced the incorporation of the progressive interface between tendon graft and bone. Biomechanical analysis showed that the HBO group achieved higher maximal pullout strength than the control group. Examination by EM showed that HBO treatment resulted in regenerated collagen fibers with increased compaction and regularity. Based on experimental results, HBO treatment is a treatment modality that potentially improves outcome following ACL reconstruction.     

关节镜下骨-髌腱-骨移植重建前十字韧带

目的关节镜下以可吸收界面螺钉固定骨-髌腱-骨(bone-patellartendon-bone,BPB)重建膝前十字韧带(ACL),并分析影响疗效的因素。方法1999年12月～2003年6月,采用关节镜下可吸收界面螺钉固定BPB移植修复ACL损伤32例,男22例,女10例;年龄20～45岁,平均32.5岁;左膝18例,右膝14例。急性损伤8例,陈旧性损伤24例。术前膝关节功能Lysholm评分平均为(52.1±5.6)分。行膝前小切口切取BPB并修整,建立骨隧道,安放胫骨侧骨块时外旋90°以适应ACL前内和后外两束的解剖结构和生理功能,采用可吸收界面螺钉固定BPB两端骨块。同时,在关节镜下处理合并损伤。术后早期行CPM功能锻炼。结果32例患者均获随访,随访6～40个月,平均32个月。采用改良Lysholm评分标准评价疗效:优24例,良7例,可1例;术后膝关节功能Lysholm评分为(98.7±3.6)分,与术前相比差异有显著性(P<0.05)。结论关节镜下可吸收界面螺钉固定BPB移植重建ACL是一种微创手术,操作简单,疗效肯定。     

钢板内固定加植骨治疗肱骨干骨折术后骨不愈合的疗效分析

目的评价钢板内固定结合自体松质骨植骨治疗肱骨干骨折术后骨不愈合的疗效。方法2002年2月～2004年12月对41例肱骨干骨折术后骨不愈合患者均采用钢板内固定结合自体松质骨植骨治疗。其中男32例,女9例;平均年龄37．5岁(17～67岁)。骨不愈合类型：肥大型16例,萎缩型25例。结果所有患者获平均22．6个月(8～42个月)随访。40例(97．6%)患_者骨折愈合,骨折愈合时间平均为5．8个月(3～12个月)。并发症：桡神经损伤3例,伤口感染1例,骨折不愈合1例。最终随访时,肩关节和肘关节功能恢复满意。结论对于肱骨干骨折术后骨不愈合的患者,采用钢板内固定加自体松质骨植骨治疗是有效的方法。     

锁定钢板内固定加植骨治疗跟骨关节内骨折

目的探讨锁定钢板内固定加植骨治疗跟骨关节内骨折的疗效。方法采用锁定钢板内固定加陶瓷骨或人工异体骨植骨治疗40例跟骨关节内骨折患者共44足,分析临床疗效。结果切口一期愈合38足,切口持续渗液4足,皮瓣坏死2足。40例均获随访,时间6~20个月。骨折愈合时间3~6个月。Bhler角由术前-15°~5°(-4.16°±3.98°)恢复至术后25°~40°(32.18°±4.28°),Gissane角由术前73.9°~91.5°(84.1°±6.28°)恢复至术后108.8°~117.4°(112.8°±5.63°),跟骨宽度由术前38~45(40.9±2.2)mm恢复至术后30~34(31.2±2.1)mm。术后无骨折畸形愈合、足弓塌陷、腓骨下端撞击综合征等并发症的发生。按Maryland评分标准评定:优29足,良10足,可4足,差1足,优良率88.6%。结论锁定钢板内固定加植骨治疗跟骨关节内骨折,能重建跟骨的大体形态,临床疗效良好。     

经皮骨移植增强对椎体生物力学性能的影响

目的 利用腰椎三维有限元模型,评价经皮骨移植增强(Optimesh(R))的生物力学性能.方法 L1～L2的三维脊柱功能单位的有限元模型由脊柱尸体标本CT扫描后形成.功能脊柱单元有限元模型有23446实体单元和310纤维单元组成,共36009个节点.模拟经皮骨移植增强(Optimesh(R))过程在L2椎体中置入松质骨粒,分析轴向压缩、前屈和后伸3种加载状态下手术前后椎体应力和应变的变化.结果 在压缩、前屈和后伸3种加载状态下,松质骨粒增强模型强化区最大的Von Mises应力分别为0.333、0.436、0.321 MPa,应变分别为0.335%、0.438%、0.322%;骨质疏松模型相应区域最大的Von Mises应力分别为0.174、0.239、0.161 MPa,应变0.512%、0.709%、0.474%.与术前(骨质疏松)模型相比,松质骨粒增强模型强化区最大的Von Mises应力增加1倍,应变下降1/3左有.结论 经皮骨移植增强(Optimesh(R))能有效地恢复椎体的生物力学性能,可为临床提供一种新的经皮椎体成型术方法.     

椎弓根螺钉固定结合可注射型人工骨治疗严重腰椎爆裂性骨折

目的 探讨应用椎弓根螺钉固定结合可注射型人工骨(MIIG)治疗严重腰椎爆裂性骨折的临床疗效. 方法 自2002年3月至2004年1月,采用此方法治疗严重腰椎爆裂性骨折患者38例,Denis分型:A型5例,B型16例,c型8例,D型3例,E型6例.观察手术前后后凸畸形、椎体前后缘高度变化、腰背疼痛VAS评分、神经功能分级,并行单因素方差统计分析. 结果 所有患者获得18～36个月(平均26个月)随访.骨折椎体近似解剖复位34例,椎体高度恢复4/5者4例,手术前后Cobb角、椎体前缘高度、腰背疼痛VAS评分手术前、后均存在明显差异(P<0.05),术后均无神经症状加重或出现新的神经症状,未见人工骨灌注后造成椎管渗漏,随着新骨的长入MIIG逐步完全被新骨替代.全部骨性愈合,无断钉、断棒、退钉及松动现象.于术后10～15个月取出内固定,骨折椎体未发生再塌陷,仅2例遗留腰背痛. 结论 严重腰椎爆裂性骨折应用椎弓根螺钉固定结合可注射型人工骨治疗可减少椎体高度、角度丢失及纠正后凸畸形,减轻腰背疼痛,手术安全性高,疗效确切.