The comparison of functional results of anterior cruciate ligament injuries treated with semitendinosus tendon and central one-third of patellar tendon autografts

The results of ACL reconstructions with autologus grafts taken from semitendinosus tendon and patellar ligament are presented. There were 78 patients in four groups. Patient age ranged from 15 to 47 years. The period of observation varied from 1 to 10 years, average 3.5. The first group consisted of 28 people treated with single semitendinosus tendon graft. In the second group there were 12 patients with acute ACL injuries treated by reinsertion of torn ligament attachment augmented by semitendinosus tendon. The third group of 18 persons had an ACL reconstruction with central one-third of patellar ligament fastened with thread loops on bone screws or staples. The last group of 20 patients had ACL reconstruction with central one-third of patellar ligament autograft. All patients were prospectively evaluated according to the Hospital for Special Surgery and the Lysholm and Gillquist scales. The statistical analysis clearly reveals the best results in the fourth group of patients, who had graft fixation with interference screws. Received: 4 April 2001/Accepted: 23 April 2001     

Local administration of alendronate reduced peri‐tunnel bone loss and promoted graft‐bone tunnel healing with minimal systemic effect on bone in contralateral knee

Continued systemic administration of alendronate was reported to reduce peri‐tunnel bone resorption and promoted graft‐bone tunnel healing at the early stage post‐anterior cruciate ligament (ACL) reconstruction. However, systemic increase in bone mineral density (BMD) in the contralateral intact knee was observed. We tested if single local administration of alendronate into the bone tunnel during ACL reconstruction could achieve similar benefits yet without the systemic effect on bone. Seventy‐two rats with unilateral ACL reconstruction were divided into three groups: saline, low‐dose (6 μg/kg) and mid‐dose (60 μg/kg) alendronate. For local administration, alendronate was applied to the bone tunnels for 2 min before graft insertion and repair. At weeks 2 and 6, the reconstructed complex was harvested for high‐resolution computed tomography (vivaCT) imaging followed by biomechanical test or histology. Our results showed that local administration of low‐dose alendronate showed comparable benefits on the reduction of peri‐tunnel bone loss, enhancement of bone tunnel mineralization, tunnel graft integrity, graft osteointegration and mechanical strength of the reconstructed complex at early stage post‐reconstruction, yet with minimal systemic effect on mineralized tissue at the contralateral intact knee. A single local administration of alendronate at the low‐dose therefore might be used to promote early tunnel graft healing post‐reconstruction. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1897–1906, 2013     

兔四股半腱肌腱重建前交叉韧带的生物力学研究

目的应用动物模型研究四股半腱肌腱重建兔前交叉韧带（ACL）后的生物力学转归以及是否可以通过将四股半腱肌腱编织改善等张性的方法促进束间融合,改善生物力学性能。方法采用成年健康新西兰大白兔32只,分为两组,每组16只,一组行常规自体四股半腱肌腱重建ACL（常规重建组）,另一组行编织的四股半腱肌腱重建ACL手术（编织组）。每组于术后26周和52周各处死8只进行ACL观察,并每组取6只行生物力学测试对比研究。结果常规重建组26及52周共16例韧带中,5例融合为一束,11例存在分束。编织组16例标本中,13例合为一束,3例呈不同程度的分束状态。生物力学测试显示：常规重建的韧带26和52周的最大载荷分别达到正常韧带的22．63％和35．87％,编织组26和52周的最大载荷达到正常韧带的33．17％和67．20％;编织组26、52周标本的最大载荷和硬度均显著高于常规重建组。结论四股半腱肌腱作为前交叉韧带的移植物,各束之间可以发生融合、部分融合以及分束的状态,原因可能与它们之间的相对运动有关,通过编织减少这种相对运动,可以促进各束融合,提高生物学及生物力学性能。     

Initial biomechanical properties of anterior cruciate ligament reconstruction autografts

To provide more information to consider when selecting a reconstruction technique, we did a side-by-side comparison of some of the initial biomechanical properties of currently accepted reconstruction methods. Our research hypotheses were that a quadrupled, woven semitendinosus and gracilis graft is as strong as any of the other commonly used graft materials and that quadrupling and weaving the hamstring graft may increase the stiffness of the overall construct Using lower extremity cadaveric specimens harvested from young donors, we fashioned seven each of seven types of graft: 9-mm, 10-mm, and 11-mm-wide patellar tendon graft (PTG); 10-mm-wide central quadriceps tendon graft; doubled semitendinosus graft; tripled semitendinosus graft; and quadrupled, woven semitendinosus and gracilis graft. Specimens were stripped of remaining soft tissue, and anterior cruciate ligament (ACL) constructs were created for biomechanical testing. The tibia was translated anteriorly on the femur, mimicking a pivot shift maneuver, andfailure strength, failure mechanism, and construct stiffness were recorded. No differences in mean strength were detected. The quadrupled, woven graft was significantly stiffer than the doubled semitendinosus graft and no less stiff than any of the PTG constructs. All grafts showed similar and adequate initial absolute strength to reconstruct the ACL. Quadrupling and weaving the semitendinosus and gracilis graft increases the stiffness of the reconstructed specimen to a level statistically similar to that of specimens reconstructed with a PTG.     

关节镜下重建前交叉韧带移植物的选择与疗效比较

目的 比较分析膝关节镜下自体和异体骨-髌腱-骨、自体半腱肌腱、异体胫前肌肌腱、LAPS人工韧带五种重建前交叉韧带方法的疗效.方法 回顾分析112例膝关节镜下自体骨-髌腱-骨移植、23例自体半腱肌肌腱移植、87例异体骨-髌腱-骨移植、126例异体胫前肌肌腱、28例LARS人工韧带重建前交叉韧带的情况.采用Lysholm评分、IKDC分级和KT-1000评价疗效.结果 前四组中期关节稳定性及功能差异无统计学意义.LAPS人工韧带近期效果与其他移植物相比有统计学意义.自体骨-髌腱-骨组膝前痛发生率高,异体骨-髌腱-骨排斥反应发生率高于异体胫前肌肌腱.结论 关节镜下前四种前交叉韧带替代物重建前交叉韧带的疗效大致相同,但LARS人工韧带近期效果优于其他移植物.     

Patellar tendon versus quadrupled bone-semitendinosus anterior cruciate ligament reconstruction: a prospective clinical investigation in athletes

Purpose:Patellar tendon and hamstrings are both used in anterior cruciate ligament (ACL) reconstruction, and comparisons have been reported with different results. The purpose of this clinical study was to compare the results of ACL reconstruction in athletes with 2 different graft types, both using bone-to-bone healing: bone-patellar tendon-bone graft and a quadrupled bone-semitendinosus graft.Type of Study:Outcomes study.Methods:From 1994 to 1997, 2 groups of 40 athletes who underwent ACL replacement with patellar tendon and quadrupled bone-semitendinosus grafts were prospectively evaluated. Preinjury activity level, age, and gender were comparable in both groups. All patients were operated on by the same surgeon within 5 months from injury and underwent group-specific rehabilitation programs. An independent examiner performed the final evaluations at 36 months. Review included clinical examination, radiographs, computed analysis, isokinetic and functional strength tests, and subjective and objective evaluation with standard knee scores. Additional procedures were recorded. Statistical analysis was performed with both parametric and nonparametric tests.Results:Average surgical time was longer with the semitendinosus graft, and postoperative pain was higher in the patellar tendon group. Standard knee evaluation scores and subjective assessment revealed no significant differences. Isokinetic testing of flexion-extension and internal-external rotation showed lower quadriceps strength and a mild deficit of external rotation in the patellar tendon group and slightly lower flexor strength in the semitendinosus group at 12 months. Computerized laxity analysis showed no difference between the 2 groups with 90% of patients having less than 3 mm side-to-side difference, with a gender difference in the semitendinosus group. Kneeling pain was higher in patellar tendon group.Conclusions:The bone-patellar tendon-bone and quadrupled bone-semitendinosus autograft provide excellent grafts for ACL reconstruction. Both techniques are comparable regarding final stability, but in patients with extensor mechanism problems or those who engage in sports with a high incidence of patellar tendonitis, the semitendinosus graft should be considered.     

Semitendinosus muscle fatty infiltration following tendon harvest in rabbits

The hamstring tendon autograft is one of the most commonly used graft choices in Anterior cruciate ligament (ACL) reconstruction. There are conflicting results regarding postoperative hamstring strength deficits in patients who have had a hamstring graft. The semitendinosus tendon has been shown to regenerate after harvesting for ACL autograft, suggesting that the muscle has the potential to regain normal function. However, no studies have been performed to define the microstructural changes that occur in the semitendinosus muscle after tendon resection. In this study, we hypothesized that fatty infiltration of the semitendinosus muscle after tendon harvest in New Zealand White rabbits increases postoperatively and remains constant or increases during the first year of repair. The semitendinosus tendon was unilaterally detached and harvested from 15 rabbits. Five rabbits were sacrificed at 3‐, 6‐, and 12‐month intervals, and the semitendinosus muscle‐tendon units were analyzed. The contralateral unoperated limb served as the control. The gross tendon and muscle dimensions and histologic percentage of fatty infiltration were measured. We found no significant difference in fatty infiltration at any time point between the control muscle and test specimens and that there was no progression of fatty infiltration over time. If these results hold true in humans, natural repair of the hamstring muscle following tendon harvest during ACL autograft reconstruction is not inhibited by fatty infiltration. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1234–1239, 2013     

Indian hedgehog signaling and the role of graft tension in tendon‐to‐bone healing: Evaluation in a rat ACL reconstruction model

The structure and composition of the native enthesis is not recapitulated following tendon‐to‐bone repair. Indian Hedgehog (IHH) signaling has recently been shown to be important in enthesis development in a mouse model but no studies have evaluated IHH signaling in a healing model. Fourteen adult male rats underwent ACL reconstruction using a flexor tendon graft. Rats were assigned to two groups based on whether or not they received 0N or 10N of pre‐tension of the graft. Specimens were evaluated at 3 and 6 weeks post‐operatively using immunohistochemistry for three different protein markers of IHH signaling. Quantitative analysis of staining area and intensity using custom software demonstrated that IHH signaling was active in interface tissue formed at the healing tendon‐bone interface. We also found increased staining area and intensity of IHH signaling proteins at 3 weeks in animals that received a pre‐tensioned tendon graft. No significant differences were seen between the 3‐week and 6‐week time points. Our data suggests that the IHH signaling pathway is active during the tendon‐bone healing process and appears to be mechanosensitive, as pre‐tensioning of the graft at the time of surgery resulted in increased IHH signaling at three weeks. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:641–649, 2016.     

Prospective clinical comparisons of semitendinosus versus semitendinosus and gracilis tendon autografts for anatomic double-bundle anterior cruciate ligament reconstruction

Background

The data available from the previously reported clinical studies remains insufficient concerning the hamstring graft preparation in double-bundle anterior cruciate ligament (ACL) reconstruction.

Objective

To test the hypothesis that there are no significant differences between the semitendinosus tendon alone and the semitendinosus and gracilis tendon graft fashioning techniques concerning knee stability and clinical outcome after anatomic double-bundle ACL reconstruction.

Methods

A prospective study was performed on 120 patients who underwent anatomic double-bundle ACL reconstruction according to the graft fashioning technique. The authors developed the protocol to use hamstring tendon autografts. When the harvested doubled semitendinosus tendon is thicker than 6 mm, each half of the semitendinosus tendon is doubled and used for the anteromedial (AM) and posterolateral (PL) bundle grafts (Group I). On the other hand, when the harvested semitendinosus tendon is under 6 mm in thickness, the gracilis tendon is harvested additionally. The distal half of the semitendinosus and gracilis tendons are doubled and used for the AM bundle graft, and the remaining proximal half of the semitendinosus tendon is doubled and used for the PL bundle grafts (Group II). Sixty-one patients were included in Group I, and 59 patients in Group II. The two groups were compared concerning knee stability and clinical outcome 2 years after surgery.

Results

The postoperative side-to-side anterior laxity averaged 1.3 mm in both groups, showing no statistical difference. There were also no significant differences between the two groups concerning the peak isokinetic torque of the quadriceps and the hamstrings, the Lysholm knee score, and the International Knee Documentation Committee evaluation.

Conclusion

There were no significant differences between the two graft fashioning techniques after anatomic double-bundle ACL reconstruction concerning knee stability and postoperative outcome. The present study provided orthopedic surgeons with important information on double-bundle ACL reconstruction with hamstring tendons.

Level of evidence

Level II; prospective comparative study.     

Nanocomposite therapy as a more efficacious and less inflammatory alternative to bone morphogenetic protein‐2 in a rodent arthrodesis model

The use of recombinant human bone morphogenetic protein‐2 (rhBMP‐2) in spine fusion has led to concerns regarding a potential accompanying inflammatory response. This study evaluates a combination therapy (TrioMatrix®; Pioneer Surgical, Inc., Marquette, MI) comprised of a demineralized bone matrix (DBM), hydroxyapatite, and a nanofiber‐based collagen scaffold in a rodent spine fusion model. Thirty‐six athymic rats that underwent a posterolateral intertransverse spinal fusion were randomly assigned to 1 of 5 treatment groups: absorbable collagen sponge alone (ACS, negative control), 10 µg rhBMP‐2 on ACS (positive control), TrioMatrix®, Grafton® (Osteotech, Inc., Eatontown, NJ), and DBX® (Synthes, Inc., West Chester, PA). Both TrioMatrix® and rhBMP‐2‐treated animals demonstrated 100% fusion rates as graded by manual palpation scores 8 weeks after implantation. This rate was significantly greater than those of the ACS, Grafton®, and DBX® groups. Notably, the use of TrioMatrix® as evaluated by microCT quantification led to a greater fusion mass volume when compared to all other groups, including the rhBMP‐2 group. T2‐weighted axial MRI images of the fusion bed demonstrated a significant host response associated with a large fluid collection with the use of rhBMP‐2; this response was significantly reduced with the use of TrioMatrix®. Our results therefore demonstrate that a nanocomposite therapy represents a promising, cost‐effective bone graft substitute that could be useful in spine fusions where BMP‐2 is contraindicated. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1812–1819, 2011     

Influence of bone adaptation on tendon‐to‐bone healing in bone tunnel after anterior cruciate ligament reconstruction in a rabbit model

Anterior cruciate ligament (ACL) reconstruction with placement of grafted tendon in bone tunnel is a common surgical procedure. Bone tunnel creation may result in stress shielding of postero‐lateral regions of tibial tunnel. The present study was designed to characterize the changes of peri‐graft bone and compare with tendon‐to‐bone (T‐B) healing in spatial and temporal manners after ACL reconstruction in rabbit. Surgical reconstruction using digital extensor tendon in bone tunnel was performed on 48 rabbits. Twelve rabbits were sacrificed at 0, 2, 6, and 12 weeks postoperatively for radiological and histological examinations. Bone mass and microarchitecture at the anterior, posterior, medial, and lateral regions of tunnel wall at distal femur and proximal tibia were evaluated. Using peripheral quantitative computed tomography, a 26, 22, and 42% decrease in bone mineral density (BMD) relative to baseline was present in the medial region of the femoral tunnel and the posterior and lateral regions of the tibial tunnel, respectively, at week 12 postoperatively (p < 0.05). It was accompanied by a decrease in trabecular number and increase in trabecular spacing, the shift of platelike to rodlike trabeculae, and loss of anisotropy under micro‐computed tomography evaluation. This finding was echoed by histology showing increased osteoclastic activities and poor T‐B healing in these regions. In conclusion, the postoperative bone loss and associated poor T‐B healing was region‐dependent, which may result from adaptive changes after tunnel creation. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1447–1456, 2009     

可吸收缝合线在移植韧带中降解性能的实验研究

目的 探讨可吸收缝合线在移植肌腱内的降解吸收机制及移植腱束之间的愈合情况。方法 15只成年新西兰大白兔，切取半腱肌，折叠成双股后，采用3个0快薇乔可吸收缝合线编织缝合，建立采用可吸收缝线编织缝合的前交叉韧带自体肌腱移植重建模型。术后观察实验动物一般情况，术后2、4、8周取材行大体及组织学观察。结果 术后动物肢体活动情况良好，大体观察实验动物前交叉韧带连续性完整，张力适中。组织学观察术后2周位于移植肌腱内部的缝合线无降解，少量炎性细胞浸润，而位于移植肌腱边缘的缝合线开始出现降解，移植腱束间通过纤维组织连接；术后4周移植肌腱内部缝合线部分降解，降解区未见新生组织长入；术后8周移植肌腱内部缝合线完全降解，形成一不规则无染色区。结论 可吸收缝合线在移植肌腱内部降解速度不变，但吸收周期明显延长。     

Comparative in vivo study of injectable biomaterials combined with BMP for enhancing tendon graft osteointegration for anterior cruciate ligament reconstruction

This study was to compare effect of osteointegration of grafted tendon in bone tunnels between injected calcium phosphate cement (ICPC) and injected fibrin sealant (IFS) combined with bone morphogenetic protein (BMP) after anterior cruciate ligament (ACL) reconstruction. ACL reconstruction was performed bilaterally in 51 rabbits. ICPC‐BMP composite was injected into one knee, with the contralateral knee IFS–BMP composite. The rabbits were killed at postoperative weeks 2, 6, and 12 for testing. Histological observations showed the ICPC composite gradually increased the new bone formation during the whole healing process, while the IFS composite had a burst effect on enhancing the healing of tendon‐to‐bone at 2 and 6 weeks. By 12 weeks, there was more new cartilage and new bone in the interface in the ICPC‐bBMP group. Micro‐CT showed that the values of BMD in the ICPC‐bBMP group were lower than those in the IFS‐bBMP group at 6 weeks, while the values in the ICPC‐bBMP group were higher than those in the IFS‐bBMP group at 12 weeks (p > 0.05). Fluorescent labels showed that the rate of new bone formation of IFS–BMP composite was significantly higher than that of ICPC composite at 6 weeks (3.45 ± 0.62 µm/day vs. 2.93 ± 0.51 µm/day), but the rate was decreased compared with ICPC composite at 12 weeks (2.58 ± 0.72 µm/day vs. 3.05 ± 0.68 µm/day; p < 0.05). Biomechanically, the ultimate failure load in the ICPC‐BMP group was always higher than that in the IFS–BMP group. It is evident that the ICPC composite achieved a more prolonged osteogenic effect than that by IFS composite. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1015–1021, 2011     

Morphology of hamstring torque‐time curves following acl injury and reconstruction: mechanisms and implications

The purposes of this study were (i) to examine the effects of anterior cruciate ligament (ACL) status on hamstring force steadiness, peak hamstring strength, quadriceps (antagonist) activation, and physical performance, and (ii) to evaluate the associations of physical performance with hamstring steadiness and hamstring strength. Thirteen subjects with unilateral deficiency of the ACL (ACLD), 39 matched subjects with unilateral reconstructed ACL (ACLR; n = 25 with bone‐patella tendon‐bone (ACLR‐PT) graft and n = 14 with combined semitendinosus and gracilis tendon (ACLR‐STGT) graft) and 33 control subjects participated. Each subject performed maximal‐effort isokinetic knee flexion repetitions at 180° s^?1 with electromyography (EMG) electrodes attached to their medial and lateral quadriceps muscles. Physical performance was assessed using the single‐limb long hop for distance. Wavelet‐derived mean instantaneous frequency (Mif) of flexor torque‐time curves was significantly (p < 0.05) higher (i.e., less smooth) in ACLR‐STGT subjects compared to the ACLD, ACLR‐PT and control subjects. No significant differences existed for peak hamstrings strength (i.e., peak torque produced) or quadriceps antagonist EMG activity. Positive correlations were identified between hamstrings force steadiness and quadriceps antagonist activity for ACLD (r = 0.797), ACLR‐PT (r = 0.467), and ACLR‐STGT (r = 0.628) subjects. For ACLR‐STGT subjects, reduced hamstrings force steadiness associated with poorer long‐hop performance (r = ?0.695). Reduced steadiness amongst ACLR‐STGT subjects may reflect motor output variability of the antagonist (i.e., quadriceps dyskinesia) and/or agonist musculature—a maladaptive feature which potentially contributes to poorer single‐limb hop performance. Measures of hamstring force steadiness in combination with traditional measures of peak hamstring strength provide valuable clinical information regarding knee joint function following ACL injury/ACLR. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:907–914     

Hamstring regrowth following harvesting for ACL reconstruction: The lizard tail phenomenon

This study evaluated the ability of the native semitendinosus tendon to regenerate after harvest for anterior cruciate ligament (ACL) reconstruction in a rabbit model. The histological and biomechanical properties of the regenerate tendons also were studied. At 16 and 28 weeks post-harvesting of the semitendinosus tendon, the regenerate tissue was evaluated by magnetic resonance imaging, gross and histologic pathologic specimens, and biomechanical evaluation. Ten of 10 specimens at 16 weeks and 10 of 10 specimens at 28 weeks demonstrated regeneration of the semitendinosus tendon, with biomechanical strength 23% of normal tendon at 16 weeks and 62% of normal tendon at 28 weeks. The results of this study support regeneration of the semitendinosus tendon to its osseous insertion on the proximal tibia after harvesting for ACL reconstruction.     

Double-bundle anatomic anterior cruciate ligament reconstruction using bone-hamstring-bone composite graft

The bone-hamstring-bone (BHB) composite graft is a hybrid ligament reconstruction methodology that combines the advantages but eliminates the disadvantages of the bone-patellar tendon-bone (BPTB) and tendon of semitendinosus and gracilis muscle (STG) methods. We have developed an innovative modified BHB method involving anatomic anterior cruciate ligament (ACL) reconstruction. It takes into account the 2 bundles of the ACL: the anteromedial bundle and the posterolateral bundle. The composite graft was prepared by folding the gracilis and the semitendinosus tendons twice and flanking the ends by bone blocks obtained from the tibia. One tunnel of 11-mm diameter was made in the tibia and the femur, and the top of the graft was introduced into the femoral socket; the distal end of the graft was rotated 90° in the counterclockwise direction for a right knee and 90° in the clockwise direction for a left knee to apply a twist to the graft, giving rise to an anteromedial bundle and a posterolateral bundle. The bone blocks attached to the graft were fixed with 2 interference screws. Modified BHB technique allows free selection of the location of the bone plug, minimizes the intra-articular length of the graft, and maintains the double-bundle structure of the original ACL.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 5 (May-June), 2002: pp 550–555     

Tendon-to-bone healing of a semitendinosus tendon autograft used for ACL reconstruction in a sheep model

Anterior cruciate ligament (ACL) reconstruction was performed in a single hind limb of 30 sheep using a doubled semitendinosus tendon graft. Three additional animals were used as controls. Histologic and biomechanical analysis was performed from 4-52 weeks postoperatively. Perpendicular collagen fibers were found connecting the tendon graft to the bone tunnels at 8 weeks. These fibers were seen circumferentially at 12 weeks. By 24 weeks, the bone tunnel was well-defined, and no further changes were observed at 52 weeks. Tendon incorporation within the femoral and tibial tunnels was similar at each interval. Although the small sample size did not permit statistical testing, the reconstruction strength was similar up to 12 weeks (15%-19% of controls). This increased at 24 (28%) and 52 (40%) weeks. The stiffness primarily increased from 4-8 weeks (18%-39%) and 24-52 weeks (52%-82%). Up to 12 weeks, failures occurred by graft pull-out from the bone tunnel. All 24- and 52-week specimens ruptured through the intra-articular portion of the graft, further indicating sufficient graft incorporation within the bone tunnels.     

兔保留与切除残迹前交叉韧带重建生物力学的比较

目的比较兔保留与切除残迹前交叉韧带（ACL）重建的生物力学差异,探讨保留残迹的意义。方法新西兰兔10只,体重（2．66±0．32）kg。切断双侧ACL,右侧股骨与胫骨端各保留残迹2mm,左侧完全切除两端残迹。切取跟腱制备移植物,对应ACL印迹解剖位分别建立胫骨与股骨隧道,重建双侧ACL。于术后8周,行单轴拉力测试。SPSS19．0软件进行数据统计。结果术后8周,保留残迹组的最大载荷（t=2．931,P〈0．05）、屈服载荷（t=2．680,P〈0．05）、刚度（t=5．411,P〈0．05）明显高于切除残迹组,两组之间差异均有统计学意义;保留残迹组拉伸长度显著低于切除残迹组,两组差异有统计学意义（t=-3．872,P〈0．05）。两组损毁模式不同,保留残迹组多表现为移植物关节内断裂,而切除残迹组多表现为移植物自骨隧道拔出。Fisher精确检验表明两组的样本损毁模式有统计学差异（P〈0．05）。结论保留残迹ACL重建的生物力学特征优于切除残迹ACL重建,提示临床采用保留残迹技术重建ACL有可能促进移植物腱-骨愈合和“韧带化”,从而改进治疗效果。     

Rekonstruktion des vorderen Kreuzbandes

The treatment of ruptures of the anterior cruciate ligament (ACL) plays an essential role for both clinicians and resident physicians. To date many questions regarding the outcome as well as ACL reconstruction techniques have not yet been conclusively clarified. Whether reconstruction of the ACL protects the knee from osteoarthritis is still unproven; however, it is well known that an unstable knee joint is more vulnerable to secondary injuries, such as meniscal tears. Thus, early ACL reconstruction is recommended to minimize the risk of these secondary injuries. Three alternative sources of material for autologous ACL reconstruction are commonly utilized. An accessory hamstring (i.e. semitendinosus tendon with or without the gracilis tendon), a central strip of the patellar tendon with bone blocks and a central strip of the quadriceps tendon with or without bone block are the most common donor tissues used in autografts. Besides selection of the type of graft, the tendon diameter also plays a crucial role. Some progress has recently been made with respect to tunnel placement. The aim is to find an anatomical tunnel position. Reconstruction of both the anteromedial and the posterolateral ACL bundles helps to rebuild the anatomy of the original ACL; however, scientifically this approach did not lead to any improvement in the results. For fixation techniques a differentiation is made between aperture, extracortical and implant-free fixation. Generally, re-ruptures are less common than revisions as a result of graft ruptures due to technical mistakes during surgery. The most common mistakes concern tunnel placement and graft fixation. Also overlooked instability can have a negative influence on the outcome of ACL reconstruction.     

Biomechanical comparisons of anterior cruciate ligament: reconstruction procedures with flexor tendon graft

An experimental study was conducted to compare the biomechanical characteristics of six currently available anterior cruciate ligament (ACL) reconstruction procedures with flexor digitorum profundus tendons. Forty porcine knees were divided into eight groups, of 5 knees each. In groups A, B, C, and D, the flexor tendon graft was fixed with sutures and an Endobutton, with 20-mm-wide polyester tapes and staples, with 10-mm-wide polyester tapes and an Endobutton, and with bone plugs and interference screws, respectively. In group E, the graft was fixed using a combined procedure of those in groups B and D. In group F, the graft was directly fixed with interference screws. In groups G and H, the bone-patellar tendon-bone graft was fixed with interference screws, and sutures, respectively. Each femur-graft-tibia complex specimen was tested with a tensile tester by anteriorly translating the tibia until failure. This study demonstrated that the biomechanical properties of the femur-graft-tibia complex reconstructed with the flexor tendon graft were significantly affected by synthetic fixation devices. Regarding the average maximal load of the groups with the flexor tendon graft, group B had the highest (893 N) and group C had the second highest (770 N). Groups E and A were in the third rank. Group F had the second lowest (312 N), and Group D had the lowest (230 N). The maximal load of group B was significantly greater (P < 0.01) than that of group G (656 N) with the bone-patellar tendon-bone grafts. As to clinical relevance, this study indicated that the flexor tendon graft can be an alternative substitute for the bone-patellar tendon-bone graft for ACL reconstruction, if we understand the biomechanical characteristics of each reconstruction procedure. Received: January 21, 2000 / Accepted: June 8, 2000