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Vascularized Patellar Tendon Graft with Rigid Internal Fixation for Anterior Cruciate Ligament Insufficiency
Abstract
After diagnosing the anterior cruciate ligament (ACL) rupture by manual and arthroscopic examination with the patient under anesthesia, the decision to augment or substitute depends on the patient's requirements. In a community of athletically motivated patients, a method of strong, durable stabilization is achieved using a pedicled patellar tendon graft with a 90 degrees twist and bone-to-bone fixation. The intercondylar notch is surgically enlarged; holes are drilled from without into the tibia and femur, the graft is harvested with bone plugs at each end, pulled into place, and transfixed with screws. Knee function is tested before closure. After operation, the emphasis is on joint ranging exercises. Quadriceps exercises are not initiated until three months after operation. Participation in a sport is not advised for approximately one year. The patellar tendon graft has all of the advantages of an autologous tissue, either for augmentation or substitution of the ACL. It has strength, durability, and elasticity; it can be transplanted with bone plugs; with the infrapatellar fat pad preserved, it retains its paratendinous vascularity. The method has been employed for five years. No graft failures have occurred, and no patient has reinjured the reconstructed ligament. Not one patient has had to give up the sport that caused the injury due to recurrent instability.
... Optimally, secure graft fixation allows for an aggressive postoperative rehabilitation program and early return to athletic activity. Several different fixation devices are available for ACL construction, [1][2][3] this implant has become the gold standard for graft fixation devices. [4][5][6] The first interference screw, utilized in ACL graft fixation was a metallic device which obtained good results. 1 At present, titanium is considered the most biocompatible metal due to its resistance to corrosion from bodily fluids, bio-inertness, capacity for osseointegration, and high fatigue limit. ...
... [4][5][6] The first interference screw, utilized in ACL graft fixation was a metallic device which obtained good results. 1 At present, titanium is considered the most biocompatible metal due to its resistance to corrosion from bodily fluids, bio-inertness, capacity for osseointegration, and high fatigue limit. Titanium interference screws provide high initial fixation strength, promote early integration into the bone, and have demonstrated reliably positive clinical outcomes and low complication rates. ...
... Titanium interference screws provide high initial fixation strength, promote early integration into the bone, and have demonstrated reliably positive clinical outcomes and low complication rates. 1,7,8 In addition, titanium interference screws have also demonstrated a higher ultimate failure strength than bioabsorbable interference screws. 8,9 Because of the good initial fixation strength of interference screws and the generally satisfactory results, some researchers have reported complications using interference screws, such as graft laceration and lack of parallelism between the bone tunnel and the screw axis. ...
The interference screw is a widely used fixation device in the anterior cruciate ligament (ACL) reconstruction surgeries. Despite the generally satisfactory results, problems of using interference screws were reported. By using additive manufacturing (AM) technology, we developed an innovative titanium alloy (Ti6Al4V) interference screw with rough surface and inter‐connected porous structure designs to improve the bone‐tendon fixation. An innovative Ti6Al4V interference screws were manufactured by AM technology. In vitro mechanical tests were performed to validate its mechanical properties. Twenty‐seven New Zealand white rabbits were randomly divided into control and AM screw groups for biomechanical analyses and histological analysis at 4, 8, and 12 weeks postoperatively; while micro‐CT analysis was performed at 12 weeks postoperatively. The biomechanical tests showed that the ultimate failure load in the AM interference screw group was significantly higher than that in the control group at all tested periods. These results were also compatible with the findings of micro‐CT and histological analyses. In micro‐CT analysis, the bone‐screw gap was larger in the control group; while for the additive manufactured screw, the screw and bone growth was in close contact. In histological study, the bone‐screw gaps were wider in the control group and were almost invisible in the AM screw group. The innovative AM interference screws with surface roughness and inter‐connected porous architectures demonstrated better bone‐tendon‐implant integration, and resulted in stronger biomechanical characteristics when compared to traditional screws. These advantages can be transferred to future interference screw designs to improve their clinical performance. The AM interference screw could improve graft fixation and eventually result in better biomechanical performance of the bone‐tendon‐screw construct. The innovative AM interference screws can be transferred to future interference screw designs to improve the performance of implants. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
... The effect of early reperfusion on the ultimate success of ACL reconstructions has been studied using vascularised (pedicled) tendon grafts, which were implanted into the knee as replacement for the ACL. [23][24][25][26][27] Promising results were reported by Lambert 23 and Benedetto and Klima 24 whereas van Rens et al, 25 Butler 26 and Butler et al 27 did not find any significant improvement in the ultimate mechanical properties of the grafts. No conclusive information on the early phase of reperfusion can be drawn from these studies because of their design. ...
... The effect of early reperfusion on the ultimate success of ACL reconstructions has been studied using vascularised (pedicled) tendon grafts, which were implanted into the knee as replacement for the ACL. [23][24][25][26][27] Promising results were reported by Lambert 23 and Benedetto and Klima 24 whereas van Rens et al, 25 Butler 26 and Butler et al 27 did not find any significant improvement in the ultimate mechanical properties of the grafts. No conclusive information on the early phase of reperfusion can be drawn from these studies because of their design. ...
... In particular, the role of connective tissue of the preserved graft on the revascularisation pattern of ACL substitutes has not been addressed. 3,4,6,7,[11][12][13]16,23,[25][26][27] In our study, only grafts which had preserved connective tissues (PTP and PTU) showed a rapid onset of revascularisation within two days after transplantation. In these grafts, the time of revascularisation was almost identical with that of other freely transplanted non-neoplastic 33 or neoplastic tissues. ...
Free patellar tendon grafts used for the intra-articular replacement of ruptured anterior cruciate ligaments (ACL) lack perfusion at the time of implantation. The central core of the graft undergoes a process of ischaemic necrosis which may result in failure. Early reperfusion of the graft may diminish the extent of this process.
We assessed the role of peritendinous connective tissue in the revascularisation of the patellar tendon graft from the day of implantation up to 24 days in a murine model using intravital microscopy. The peritendinous connective-tissue envelope of the graft was either completely removed, partially removed or not stripped before implantation into dorsal skinfold chambers of recipient mice.
Initial revascularisation of the grafts with preserved peritendinous connective tissues began after two days. The process was delayed by five to six times in completely stripped patellar tendons (p < 0.05). Only grafts with preserved connective tissues showed high viability whereas those which were completely stripped appeared to be subvital.
The presence of peritendinous connective tissues accelerates the revascularisation of free patellar tendon grafts.
... La prótesis ideal debe proveer una función biológica adecuada, ser biocompatible y permitir el desarrollo y el crecimiento de colágeno en el interior de la prótesis, lo cual contribuye al refuerzo del ligamento y a su estabilidad y durabilidad durante largo tiempo (213) . Sin embargo, es necesaria una nueva generación de ligamentos sintéticos que combinen las ventajas de los materiales sintéticos (alta resistencia, fácil fabricación y almacenamiento) y los injertos biológicos (biocompatibilidad y crecimiento tisular) (214) . El colágeno, por sus características físicas, químicas y biológicas, es un material que puede ser interesante para el desarrollo de prótesis ligamentosas, al ser el mayor componente extracelular del LCA (215) que puede ser procesado en fibras reabsorbibles de alta resistencia, con diámetros semejantes al del LCA. ...
... El colágeno, por sus características físicas, químicas y biológicas, es un material que puede ser interesante para el desarrollo de prótesis ligamentosas, al ser el mayor componente extracelular del LCA (215) que puede ser procesado en fibras reabsorbibles de alta resistencia, con diámetros semejantes al del LCA. El colágeno es biocompatible sin presentar problemas antigénicos y, además, es quimiotáctico para los fibroblastos y otras células que aparecen en el tejido de reparación (214) . ...
... In the early 1980s, Dandy used an arthroscope, originally designed for meniscal tears, to perform the first arthroscopic ACL reconstruction [19]. The refinement of interference screw fixation further increased reliability of intra-articular ACL reconstruction, diminishing the need for extra-articular procedures [20,21]. In 1989, extra-articular procedures were abandoned in the United States after the AOSSM published a consensus that they were not beneficial and concerns were raised about potential post-operative stiffness and late osteoarthritis [22]. ...
... The graft was then fixed using wires and extra-articular screws. In this context, the introduction of interference screws brought a significant improvement (40,41). As these techniques became more reliable and refined, the need for anterolateral tenodesis declined. ...
Management of anterior cruciate ligament (ACL) tears has continuously evolved since its first description in approximately 170 A.D. by Claudius Galenus of Pergamum and Rome. The initial immobilization using casts was replaced by a variety of surgical and conservative approaches over the past centuries. The first successful case of ACL repair was conducted by Mayo Robson in 1885, suturing cruciate at the femoral site. In the nineteenth century, surgical techniques were focused on restoring knee kinematics and published the first ACL repair. The use of grafts for ACL reconstruction was introduced in 1917 but gained popularity in the late 1900s. The introduction of arthroscopy in the 1980s represented the greatest milestones in the development of ACL surgery, along with the refinements of indications, development of modern strategies, and improvement in rehabilitation methods. Despite the rapid development and multitude of new treatment approaches for ACL injuries in the last 20 years, autografting has remained the treatment of choice. Compared to the initial methods, arthroscopic procedures are mainly performed,and more resistant and safer fixation devices are available. This results in significantly less trauma from the surgery and more satisfactory long-term results. The most commonly used procedures are still patellar tendon or hamstring autograft. Additionally, popular, but less common, is the use of quadriceps tendon(QT) grafts and allografts. In parallel with surgical developments, biological reconstruction focusing on the preservation of ACL remnants through the use of cell culture techniques, partial reconstruction, tissue engineering, and gene therapy has gained popularity. In 2013, Claes reported the discovery of a new ligament[anterolateral ligament (ALL)] in the knee that could completely change the treatment of knee injuries. The intent of these modifications is to significantly improve the primary restriction of rotational laxity of the knee after ACL injury. Kinematic studies have demonstrated that anatomic ACL reconstruction and anterolateral reconstruction are synergistic in controlling pivot displacement. Recently, there has been an increased focus on the application of artificial intelligence and machine learning to improve predictive capability within numerous sectors of medicine, including orthopedic surgery,
... Interference screw designs have evolved from 6.5 mm AO metallic screws to a more contemporary bioabsorbable screw composition [1,15,16]. Prior studies, primarily focusing on the use of metallic screws on tibial tunnel fixation using soft tissue grafts, have observed several variables influencing fixation strength such as screw geometry, insertional torque, and bone quality [17][18][19][20][21][22]. As such, there remains limited evidence on effect of interference screw diameter on femoral-sided aperture fixation strength using modern bioabsorbable screws [1]. ...
Purpose: The purpose of this study was to evaluate the effect of bioabsorbable interference screw diameter on the pullout strength and failure mode for femoral tunnel fixation in primary anterior cruciate ligament reconstruction (ACLR) at time zero fixation using bone-patellar tendon-bone (BTB) autograft in a cadaveric model.
Methods: Twenty-four fresh-frozen cadaveric knees were obtained from 17 different donors. Specimens were allocated to three different treatment groups (n = 8 per group) based on interference screw diameter: 6 mm, 7 mm, or 8 mm biocomposite interference screw. All specimens underwent dual energy X-ray absorptiometry (DEXA) scanning prior to allocation to ensure no difference in bone mineral density among groups (n.s.). All specimens underwent femoral-sided ACLR with BTB autograft. Specimens subsequently underwent mechanical testing under monotonic loading conditions to failure. The load to failure and failure mechanism were recorded.
Results: The mean pullout force (N) at time zero for each group was 309 ± 213 N, 518 ± 313 N, and 541 ± 267 N for 6 mm, 7 mm, and 8 mm biocomposite interference screw diameter, respectively (n.s.). One specimen in the 6 mm group, two specimens in the 7 mm group, and one specimen in the 8 mm group failed by screw pullout. The remainder in each group failed by graft failure (n.s.).
Conclusion: Biocomposite interference screw diameter did not have a significant influence on fixation pullout strength or failure mode following femoral tunnel fixation using BTB autograft at time zero. A 6 mm interference screw can improve preservation of native bone stock, increase potential for biologic healing, and decrease the risk of damage to the graft during insertion without significantly compromising fixation strength. This study supports the use of smaller 6 mm interference screw diameter options for femoral tunnel fixation in ACLR.
... In the 1980s, with the advent of arthroscopy, screw with washer fixation became widely used. Around that time, Lambert described intra-tunnel fixation with a cortical screw [27,28]. ...
Anterior cruciate ligament (ACL) insufficiency can be disabling, given the physical and sports activity constraints that negatively impact the quality of life. Consequently, surgery is the main approach for most active patients. Nonetheless, ACL reconstruction cannot be successful without adequate pre- and postoperative rehabilitation. Since the 1960s, post-ACL reconstruction rehabilitation has evolved, mainly from advances in surgery, coupled with a better understanding of the biological concepts of graft revascularization, maturation and integration, which have impacted ACL postoperative rehabilitation protocols. However, new technologies do involve a definite learning curve which could affect rehabilitation programs and produce inconsistent results. The development of rehabilitation protocols cannot be defined without an accurate diagnosis of ACL injury and considering the patient's main physical demands and expectations. This article discusses how postoperative rehabilitation following ACL reconstruction has changed from the 1960s to now, focussing on surgical technique (type of tendon graft, fixation devices, and graft tensioning), biological concepts (graft maturation and integration), rehabilitation protocols (prevention of ACL injuries, preoperative rehabilitation, postoperative rehabilitation), criteria to return to sports, patient's reported outcomes (PROM), and outcome. Although rehabilitation plays an essential role in managing ACL injuries, it cannot be fully standardized pre- or postoperatively. Pre- and postoperative rehabilitation should be based on an accurate clinical diagnosis, patients' understanding of their injury, graft tissue biology and biomechanics, surgical technique, the patient's physical demands and expectations, geographical differences in ACL rehabilitation, and future perspectives.
... Different combinations of synthetic materials have been used: PGA (polyglycolic acid), copolymers of PGA/PLA (polyglycolic acid/poly lactic acid), polyparadioxanone and various stereoisomers of lactic acid, poly-L-lactic acid and poly-D-lactic acid 4,5,6 . Traditionally, metallic interference screws (MISs) have afforded reliably positive clinical outcomes, prevention of excessive laxity, and low complication rates 7 . MISs promote early integration into bone with high initial fixation strength and have a higher failure-load than bioabsorbable interference screws (BISs) in biomechanical studies 8 . ...
“A COMPARATIVE EVALUATION OF BIODEGRADABLE VERSUS METALLIC INTERFERENCE SCREW FOR TIBIAL SIDED ACL RECONSRUCTION”
ABSTRACT
Background: Traditionally, metallic interference screws have a higher failure load than bioabsorbable interference screws in ACL reconstruction. We studied the comparative evaluation of biodegradable and metallic interference screw for tibial sided ACL reconstruction.
Material And Methods : This a prospective comparative study conducted in 50 patients aged between 15-55 years with MRI evidence of complete ACL tear, fulfilling inclusion and exclusion criteria, treated Arthroscopically with ACL reconstruction were followed up for an average duration of 12 months. Lysholm and Gillquist Knee Scoring Scale was used and outcome scores were divided into Excellent, Good, Fair and Poor.
Results: In our study 41 patients were male and 9 were female. Bio screw was used in 24 male and 6 female patients. Metallic screw was used in 17 male and 3 females. Outcome score was excellent in 26 (52%) cases, good in 18 (36%) cases, fair in 4 (8%) cases, poor in 2 (4%) cases. The mean lysholm score in bioabsorbable group was 93.13 and in metallic group was 89.70. Knee effusion was higher in bio screw group and infection rate was higher in metallic group.
Conclusion: Our study showed no significant difference in the final patient outcomes in ACL reconstruction performed using bioabsorbable or metallic screws. Bioabsorbable materials may be preferable because of their final osteo-integration, but higher costs and equivalent results achieved when compared with metallic screws, bioabsorbable screws still cannot be fully supported as more effective fixation devices.
KeyWords: ACL, Bioabsorbable interference screws, Metallic interference Screws.
... Metallic interference screws have demonstrated positive clinical outcomes with low complication rates. 14,21 Although this method of fixation has demonstrated excellent long-term results and return to premorbid levels, it creates secondary issues. Metallic screws have been associated with graft damage during insertion, they hinder subsequent imaging with metallic artifact, and they may pose difficulties at revision or subsequent surgery. ...
Background
Bioabsorbable screws for anterior cruciate ligament reconstruction (ACLR) have been a popular choice, with theoretical advantages in imaging and surgery. Titanium and poly-L-lactic acid with hydroxyapatite (PLLA-HA) screws have been compared, but with less than a decade of follow-up.
Purpose/Hypothesis
The purpose was to compare long-term outcomes of hamstring autograft ACLR using either PLLA-HA screws or titanium screws. We hypothesized there would be no difference at 13 years in clinical scores or tunnel widening between PLLA-HA and titanium screw types, along with high-grade resorption and ossification of PLLA-HA screws.
Study Design
Randomized controlled trial; Level of evidence, 1.
Methods
Forty patients undergoing ACLR were randomized to receive either a PLLA-HA screw or a titanium screw for ACL hamstring autograft fixation. Blinded evaluation was performed at 2, 5, and 13 years using the International Knee Documentation Committee score, Lysholm knee score, and KT-1000 arthrometer. Magnetic resonance imaging (MRI) was performed at 2 or 5 years and 13 years to evaluate tunnel volumes, ossification around the screw, graft integration, and cyst formation. Computed tomography (CT) of patients with PLLA-HA was performed at 13 years to evaluate tunnel volumes and intratunnel ossification.
Results
No differences were seen in clinical outcomes at 2, 5, or 13 years between the 2 groups. At 13 years, tibial tunnel volumes were smaller for the PLLA-HA group (2.17 cm ³ ) compared with the titanium group (3.33 cm ³ ; P = .004). By 13 years, the PLLA-HA group had complete or nearly complete resorption on MRI or CT scan.
Conclusion
Equivalent clinical results were found between PLLA-HA and titanium groups at 2, 5, and 13 years. Although PLLA-HA screws had complete or nearly complete resorption by 13 years, tunnel volumes remained largely unchanged, with minimal ossification.
... Moreover, interference fit fixation of the bone of the physioTherapy (PT) graft has been known to be superior to other types of fixation. Another advantage that the bone peg unites in approximately 6 weeks allows early rehabilitation of the knee [21,22]. In addition, early weight bearing after ACL reconstruction with the PT graft and interference screw fixation was discussed and accepted by many authors [23,24]. ...
... Metallic interference screws have demonstrated positive clinical outcomes with low complication rates. 14,21 Although this method of fixation has demonstrated excellent long-term results and return to premorbid levels, it creates secondary issues. Metallic screws have been associated with graft damage during insertion, they hinder subsequent imaging with metallic artifact, and they may pose difficulties at revision or subsequent surgery. ...
... In fact, a PubMed search in June 2017 reveals over 350 articles on the topic of intercondylar notch and ACL. As early as 1983, the intercondylar notch was implicated in ACL injury (32,33). Subsequently in 1987, Houseworth et al. used computer graphic analysis to suggest that narrow notch width may predispose the individual to ACL injury (34). ...
... These screws have been used since the 1980's and were initially made of metal. 3 Metallic interference screws are complicated by damage to the graft or sutures, disruption of magnetic resonance imaging (MRI), and the need for their removal during any subsequent revision surgeries. 4,5 Bioabsorbable interference screws were developed as an alternative to metallic screws and have been shown to have equivalent fixation strength and clinical results. ...
Current treatment options for cartilage injuries are limited. The goals of this study are to create a biodegradable polymer scaffold with the capabilities of sustaining chondrocyte growth and proliferation, enable cell-to-cell communication and tissue regeneration through large pores, and assess the biological augmentation of the scaffold capabilities using platelet lysate (PL). We synthesized biodegradable polycaprolactone fumarate (PCLF) scaffolds to allow cell-cell communication through large interconnected pores. Molds were printed using a three-dimensional printer and scaffolds synthesized through UV crosslinking. Culture medium included alpha modified Eagle's media with either 10% fetal bovine serum (FBS) or 5% PL, a mixture of platelet release products, after being seeded onto scaffolds through a dynamic bioreactor. Assays included cellular proliferation (MTS), toxicity and viability (live/dead immunostaining), differentiation (glycosaminoglycan [GAG], alkaline phosphatase [ALP], and total collagen), and immunostaining for chondrogenic markers collagen II and Sox 9 (with collagen I as a negative control). The large interconnected pores (500 and 750??m) enable cell-to-cell communication and cellular infiltration into the scaffolds, as the cells remained viable and proliferated for 2 weeks. Chondrocytes cultured in PL showed increased rates of proliferation when compared with FBS. The chondrogenic markers GAG and total collagen contents increased over 2 weeks at each time point, whereas the osteogenic marker ALP did not significantly change. Immunostaining at 2 and 4 weeks for the expression of chondrogenic markers Collagen II and Sox 9 was increased when compared with control human fibroblasts. These results show that the PCLF polymer scaffold enables chondrocytes to attach, proliferate, and retain their chondrogenic phenotypes, demonstrating potential in chondrocyte engineering and cartilage regeneration.
... These screws have been used since the 1980's and were initially made of metal. [3] Metallic interference screws are complicated by damage to the graft or sutures, disruption of magnetic resonance imaging (MRI), and the need for their removal during any subsequent revision surgeries. [4,5] Bioabsorbable interference screws were developed as an alternative to metallic screws and have been shown to have equivalent fixation strength and clinical results. ...
Anterior cruciate ligament (ACL) ruptures reconstructed with tendon grafts are commonly fixed with bioabsorbable implants, which are frequently complicated by incomplete bone filling upon degradation. Bone regeneration after ACL reconstruction could be enhanced by utilizing tissue engineering techniques and three-dimensional (3D) printing to create a porous bioabsorbable scaffold with delayed delivery of recombinant-human bone morphogenetic protein 2 (rhBMP-2). The first aim of this study was to design a 3D PPF porous scaffold that maintained suitable pull-out strength for future testing in a rabbit ACL reconstruction model. Our second aim was to determine the release kinetics of rhBMP-2 from PPF scaffolds that utilized both calcium-phosphate coatings and growth factor delivery on microspheres, both of which have been shown to decrease the initial burst release of rhBMP-2 and increase bone regeneration. To determine the degree of scaffold porosity that maintained suitable pull-out strength, tapered scaffolds were fabricated with increasing porosity (0%, 20%, 35%, and 44%) and pull-out testing was performed in a cadaveric rabbit ACL reconstruction model. Scaffolds were coated with carbonate hydroxyapatite (synthetic bone mineral, SBM) and radiolabeled rhBMP-2 was delivered in four different experimental groups: Poly(lactic-co-glycolic acid) PLGA microspheres only, microspheres and collagen (50:50), collagen only, and saline solution only. rhBMP-2 release was measured at day one, two, four, eight, sixteen, and thirty-two. The microsphere delivery groups had a smaller burst release and released a smaller percentage of rhBMP-2 over the 32 days than the collagen and saline only groups. In conclusion, a porous bioabsorbable scaffold with suitable strength for a rabbit ACL reconstruction was developed. Combining a synthetic bone mineral coating with microspheres had an additive effect, decreasing the initial burst release and cumulative release of rhBMP-2. Future studies need to evaluate this scaffold's fixation strength and bone filling capabilities in vivo compared to traditional bioabsorbable implants.
... (1983) ise tünel içerisinde kemik blokların internal rijid tespiti ile kemik-kemiğe kaynamanın ve stabilitenin artacağını belirtmişlerdir. [12] Lambert'a atıfta bulunan Kurosaka ve ark. (1987) yaptıkları kadavra çalışmasında, bu konudaki en önemli gelişmeyi kaydetmişlerdir. ...
... Since Lambert (1983) introduced interference screw fixation of bone-patellar tendon-bone grafts, design, and performance of these screws have gradually improved. First generations of these screws were made by metallic biomaterials. ...
The purpose of this study was to produce and evaluate different mechanical, physical and in vitro cell culture characteristics of poly(L-lactic) acid (PLLA) interference screws. This work will focus on evaluating the effect of two important parameters on operation of these screws, first the tunnel diameter which is one of the most important parameters during the operation and second the thermal behavior, the main effective characteristic in production process. In this work, PLLA screws were produced by a two-stage injection molding machine. For mechanical assessment of the produced screws, Polyurethane rigid foam was used as cancellous bone and polypropylene rope as synthetic graft to simulate bone and ligament in real situation. Different tunnel diameters including 7–10 mm were evaluated for fixation strength. When the tunnel diameter was changed from 10 to 9 mm, the pull-out force has increased to about 12 %, which is probably due to the aforementioned frictional forces, however, by reducing the tunnel diameter to 8 and 7 mm, the pull-out force reduced to 16 and 50 % for 8 and 7 mm tunnel diameter, respectively. The minimum and maximum pull-out force was obtained 160.57 and 506.86 N for 7 and 9 mm tunnel diameters, respectively. For physicochemical assay, Fourier transform infrared spectroscopy (FTIR), degradation test and differential scanning calorimetry (DSC) were carried out. The crystallinity (Xc) of samples were decreased considerably from 64.3 % before injection to 32.95 % after injection with two different crystallographic forms α′ and α. probably due to the fast cooling rate at room temperature. In addition, MTT and cell attachment assays were utilized by MG63 osteoblast cell line, to evaluate the cytotoxicity of the produced screws. The results revealed no cytotoxicity effect.
... Bioabsorbable interference (BioRCI) screws were first described by Lambert and Kurosaka et al. [22,23]. According to an Ambrose and Clanton [24] review, the bioabsorbable implants provide strong fixation of the graft, the possibility of revision surgery, a low level of inflammatory response, a low incidence of adverse reactions and good biological incorporation of the graft into the tunnel. ...
Background. The reconstruction of the anterior cruciate ligament (ACL) of the knee joint is a standard in ACL complete rupture treatment in athletes. One of the weakest points of this procedure is tibial fixation of grafts.
Objectives. The aim was, firstly, to evaluate patients 3–4 years after primary ACL reconstruction with the use of autologous ipsilateral STGR grafts and with tibial fixation using a bioabsorbable interference screw composed of PLLA-HA or WasherLoc, comparing the postoperative result to the preoperative condition and, secondly, to compare the results between the two groups of patients with different tibial fixation.
Material and Methods. Group I consisted of 20 patients with a bioabsorbable interference screw composed of PLLA-HA tibial fixation. In Group II, there were 22 patients after ACL reconstruction with the use of WasherLoc tibial fixation. The Lachman test, pivot-shift test, Lysholm Knee Scoring Scale and 2000 International Knee Documentation Committee (2000 IKDC) Subjective Knee Evaluation Form were used to evaluate the results.
Results. The intra-group comparison of the results of the 2000 IKDC Subjective Knee Evaluation Form and Lysholm Knee Scoring Scale obtained in the groups studied showed statistically significant differences between the evaluation performed preoperatively and postoperatively. The inter-group comparison of the results of the 2000 IKDC Subjective Knee Evaluation Form and Lysholm Knee Scoring Scale obtained postoperatively showed no statistically significant differences between the two groups.
Conclusion. An evaluation 3–4 years after ACL reconstruction with the use of autologous ipsilateral STGR grafts demonstrated significant progress from the preoperative condition to the postoperative result in patients with tibial fixation using a bioabsorbable interference screw composed of PLLA-HA as well as in patients with WasherLoc tibial fixation. There were no differences found between the two groups of patients after ACL reconstruction in terms of manual stability testing or a subjective assessment of knee joint outcomes.
... Kurosaka et al. [ 2 ] described some of the concepts of interference screw fi xation with a custom designed, fully threaded 9.0-mm cancellous screw with increased stiffness and linear load compared with initial Lambert's 6.5-mm cancellous AO screw [ 3 ] . ...
The current development of bioresorbable materials provided the support for improvement of the clinical performance of the interference screws used during knee-ligament reconstruction. In general, commercially available biodegradable interference screws used in clinical practice are chemically based on degradable, but now a trend to use biodegradable composite materials using the same synthetic biodegradable polymers as matrix reinforced with biodegradable ceramics could be observed. Hydroxyapatite or tricalcium phosphate are used as ceramics in order to reduce the foreign body reaction and increase osteoconduction and mechanical properties of the biodegradable composite materials. In our study several new design features of an innovative interference screw were proposed in order to ameliorate press-fit fixation without damaging the graft based on clinical experience, retrieval analysis of some failed screw, and finite element simulation. We proposed a self-tapping screw with conical shape and three cutting flutes at the distal end and cylindrical shape at the proximal end. The clinical performance of an interference screw is assured by the combination between the clinical technique, screw design, and biodegradable composite material properties, which guarantees the integrity of the screw during insertion, the tissue regrowth, and the stability of fixation.
... La utilización del tercio central del ligamento rotuliano se considera el tejido autólogo de elección para los deportistas por su resistencia, durabilidad y elasticidad [28][102] [103]. Este procedimiento tiene también sus inconvenientes por el compromiso del aparato extensor de la rodilla y se han descrito disminución del perímetro y restricciones de la movilidad [104] [105]. ...
Tibialis anterior tendon (TAT) transfer to the lateral cuneiform is commonly utilized to treat dynamic supination for relapsed clubfoot deformity. Traditional suture button fixation (SBF) may lead to skin necrosis at the button/skin interface. While interference screw fixation (ISF) would mitigate this concern, this fixation method has not been investigated in clubfoot patients. This study aims to investigate the performance of ISF versus SBF for TAT transfer in a cadaveric model. Ten matched pairs of cadaveric feet were obtained. One of each matched specimen underwent TAT transfer to the lateral cuneiform using ISF and the other underwent TAT transfer using SBF. For each ISF specimen, the tension of the transferred TAT required to bring the ankle to neutral was measured. This tension was then applied to both matched specimens using an MTS machine. Tension dissipation was measured after a 20-minute interval. In specimens with SBF, a load cell was positioned between the plantar skin and suture button to determine plantar skin pressure at the time of initial tension application. Average tension necessary to achieve neutral dorsiflexion was 49.4 N. Average tension dissipation after 20 min was significantly less in the IFS group (20 N versus 23.6 N, P = 0.02). No fixation failures occurred in either group. Average plantar foot skin pressure was 196.5 mmHg at initial tension application, exceeding thresholds for tissue ischemia. ISF allows for tendon tensioning at forces beyond those expected to result in skin necrosis with SBF with less dissipation of tension over time.
The incidence of screw loosening, migration, and pullout caused by the insufficient screw-bone fixation stability is relatively high in clinical practice. To solve this issue, the auxetic unit-based porous bone screw (AS) has been put forward in our previous work. Its favorable auxetic effect can improve the primary screw-bone fixation stability after implantation. However, porous structure affected the fatigue behavior and in vivo longevity of bone screw. In this study, in vitro fatigue behaviors and in vivo osseointegration performance of the re-entrant unit-based titanium auxetic bone screw were studied. The tensile-tensile fatigue behaviors of AS and nonauxetic bone screw (NS) with the same porosity (51%) were compared via fatigue experiments, fracture analysis, and numerical simulation. The in vivo osseointegration of AS and NS were compared via animal experiment and biomechanical analysis. Additionally, the effects of in vivo dynamic tensile loading on the osseointegration of AS and NS were investigated and analyzed. The fatigue strength of AS was approximately 43% lower while its osseointegration performance was better than NS. Under in vivo dynamic tensile loading, the osseointegration of AS and NS both improved significantly, with the maximum increase of approximately 15%. Preferrable osseointegration of AS might compensate for the shortage of fatigue resistance, ensuring its long-term stability in vivo. Adequate auxetic effect and long-term stability of the AS was supposed to provide enough screw-bone fixation stability to overcome the shortages of the solid bone screw, developing the success of surgery and showing significant clinical application prospects in orthopedic surgery.
The replacement of the anterior cruciate ligament (ACL) is currently one of the most common surgical procedures in orthopedic surgery. Every year about 40,000 ACL replacements are performed in Germany. This is an overview of the development of the surgical techniques. The evolution of surgical techniques goes back over more than 100 years. The anatomy of the ACL was described by the Weber Brothers in 1836 in Göttingen, Germany, and they precisely described the anatomical insertions, fiber structures, and functional bundles. In 1921, Testut and Jakob provided a very detailed anatomical relationship between ACL insertion, the lateral meniscus, and the tibial plateau. In the international literature the first ACL reconstruction was performed in 1917 by Hey Groves in Bristol, who replaced an ACL with a strip out of the iliotibial tract. Several periods, from the patellar tendon to the quadriceps and hamstring tendon, decades of graft, type of fixation followed up to now.
Good to excellent results at long-term follow-up have been published for anterior cruciate ligament reconstruction with bone-tendon-bone graft. Despite improvements in fixation devices, concerns regarding the stability of graft fixation on the tibial side remain. We present supplementary tibial fixation for anterior cruciate ligament reconstruction with bone-tendon-bone graft using a transosseous technique that is simple and inexpensive and avoids the risk of symptomatic hardware.
Background:
While the transfer of the tibialis anterior tendon (TAT) to the lateral cuneiform (LC) following serial casting has been used for nearly 60 years to treat relapsed clubfoot deformity, modern methods of tendon fixation remain largely unstudied. Interference screw fixation represents an alternative strategy that obviates concerns of plantar foot skin pressure-induced necrosis and proper tendon tensioning associated with button suspensory fixation. A better understanding of LC morphology in young children is a necessary first step in assessing the viability of this fixation technique. Therefore, the purpose of this investigation is to define LC morphology and TAT width in children aged 3 to 6 years.
Methods:
A retrospective radiographic review of 40 healthy pediatric feet aged 3 to 6 years who had either magnetic resonance imaging or computed tomography scans was performed at a single pediatric hospital. The length, width, and height of only the ossified portion of the LC were measured digitally using sagittal, coronal, and axial imaging. In addition, the maximal cross-sectional diameter of the TAT was measured at the level of the tibiotalar joint.
Results:
The average ossified LC width ranged from 8.5 mm in the 3-year-old cohort to 10.3 mm in 6-year-old children. Analysis of variance testing revealed no statistically significant difference in width between age groups. Average ossified LC length ranged from 13.5 mm in the 3-year-old cohort to 18.3 mm in 6-year-old children with statistically significant increases in age groups separated by 2 or more years. Significant differences in LC height, volume, and TAT diameter were demonstrated after analysis of variance testing. The TAT to ossified LC width ratio ranged from 44% to 53% across age groups.
Conclusions:
The dimensions of the LC ossification center are large enough to allow interference screw fixation in children 3 to 6 years of age. Further studies are needed to investigate interference screw fixation performance in the pediatric clubfoot population.
Level of evidence:
Level IV.
The increasingly serious complications of artificial ligaments and allografts have brought them into disrepute. Recently, autografts have drawn more attention. A new type of autograft, the Achilles tendon autograft, has been developed and applied to anterior cruciate ligament reconstructions. This report describes the advantages of the Achilles tendon autograft used and presents the results of a prospective study of 21 patients with minimum 2 year follow up. Of the 21 cases, 16 patients (75%) had a rating of excellent; 2 (10%) good, 2 (10%) fair, and 1 (5%) poor. Preoperative knee scores of 56.7 were improved to 89.5 postoperatively. The authors removed less than half of the Achilles tendon with the calcaneal bone incorporated. Through magnetic resonance imaging we confirmed that the remaining Achilles tendon of the donor site regained its volume and strength within a year without significant complication. Achilles tendon autograft offers the advantages of length, elastic strain modulus, reproducibility in technique, and consistency of the result without significant complications.
» Anterior cruciate ligament (ACL) reconstruction is a commonly performed orthopaedic procedure with numerous reconstructive graft and fixation options. Interference screws have become one of the most commonly utilized methods of securing ACL grafts such as bone-patellar tendon-bone (BPTB) autografts.
» The composition of interference screws has undergone substantial evolution over the past several decades, and numerous advantages and disadvantages are associated with each design.
» The composition, geometry, and insertional torque of interference screws have important implications for screw biomechanics and may ultimately influence the strength, stability of graft fixation, and biologic healing in ACL reconstruction.
» This article reviews the development and biomechanical properties of interference screws while examining outcomes, complications, and gaps in knowledge that are associated with the use of femoral interference screws during BPTB ACL reconstruction.
There has been a growing interest in the use of bioabsorbable polymers in interference screws for knee ligament reconstruction surgeries. This interest is driven by virtue of the relevant properties exhibited by these polymers. Among such essential properties include excellent biocompatibility and bioabsorption, good integration between graft/bone, in addition to the ease they offer when it comes to surgical revision. This article seeks to report the results obtained from the study aimed at the development of a bioabsorbable interference screw produced by the injection molding process with two distinct polymeric materials: PLDL poly(L,DL‐Lactic acid) and a composite PLDL + 30 wt% TCP (β‐tricalcium phosphate). Finite element analysis (FEA) was used for the development of the screw design. The mechanical strength of the screws was evaluated, where the maximum torque to break was found to surpass the insertion torque by 136% in PLDL material and by 190% in PLDL+TCP. The mean values of pullout force obtained for PLDL and PLDL+TCP were 1635 N and 809 N, respectively. An in vitro degradation test performed over a period of 180 days helped to assess the mechanical behavior during degradation and facilitated the comparison of the screws based on specific application requirements. The composite material (PLDL+TCP) exhibited a faster degradation process, with 88% loss of mechanical resistance following 180 days of degradation compared with 55% observed in the PLDL material. The results show that the addition of bioactive ceramic TCP contributed toward raising the initial mechanical resistance and acceleration during the process of degradation. POLYM. COMPOS., 2018.
This chapter briefly discusses the biologic processes for natural cranial cruciate ligament (CrCL), healing, as well as the biological steps occurring during the healing of a reconstructed CrCL graft. Unlike the extracapsular medial collateral ligament (MCL), the intracapsular CrCL does not heal without early surgical intervention. The partially torn CrCL initially exhibits a weak healing response. Surgical repair of the CrCL via suturing the ligament ends together immediately after injury can provide some degree of healing. Similar to the extracapsular MCL, the sutured CrCL undergoes inflammation, proliferation and remodeling, albeit a slower process. Rupture of the CrCL often involves reconstruction with an autograft or allograft due to the poor functional outcomes with non-operative treatment. CrCL reconstruction requires healing of the tendon graft and bone tunnels in the femur and tibia. Repair of the CrCL proceeds via the formation of a fibrovascular interface tissue.
The first part of The story of anterior cruciate ligament reconstruction, was published in the previous issue of this journal, and the reader is encouraged to study both parts in order to become better acquainted with the subject. Those who have read the first part will remember that it concerned the historical developments surrounding the ligament's discovery, the acknowledgement of its function and the appreciation of the detrimental effects once it becomes damaged. It also described the efforts of the early pioneers who recognised the need to reestablish ligament function by ways of ligament repair or reconstruction with autologous tissue. The second part, presented here, explores the surgeons' quests to find the ideal graft material by experimenting with various synthetic materials, as well as those derived from animals (xenografts) and other human beings (allografts). It looks at historic efforts to stabilise an unstable knee by means of extra-articular reinforcements which were popular until not too long ago and reviews the developments of the various graft fixation methods available today. Furthermore it evaluates the influence of arthroscopy which revolutionised not just the procedure of ACL reconstruction but knee surgery in general, and also focuses on the more recent developments of double bundle techniques and the recreation of the ligament's native anatomy.
Anatomic ACL reconstruction depends on adequate time-zero graft fixation to allow for graft incorporation and subsequent knee stability. Biomechanical testing has demonstrated significant differences between fixation devices and excellent clinical results have been reported using a wide variety of fixation devices and techniques. This chapter explores a number of these factors and their relevance in obtaining ideal ACL intratunnel fixation.
In anterior cruciate ligament (ACL) graft surgeries, the location of the insertion point is a critical definition for the functional success of the surgery and patient health. This location is determined during preoperative planning and can be defined according to some criteria such that the biomechanical function is preserved in its best. In this work, simulations based on the method previously presented in part A are presented, taking experimental data available in the literature. Here, this clinical application uses the in situ force of the ACL at selected insertion points as criteria. This aims to determine the graft insertion points, at femur, that best leads to the natural response of an intact knee. Results show the applicability of the method as a support tool for medical decision making in the preoperative planning period.
The BTB autograft, which is morphologically and biomechanically suitable in mimicking the native ACL, has long been considered the gold standard for ACL reconstruction. Although this technique provides good long-term clinical results, including a higher rate of returning to previous sporting levels, BTB ACL reconstruction is associated with many technical difficulties and high risks of donor-site morbidity and osteoarthritis. The abovementioned issues, however, could be reduced by modifying surgical techniques, such as anatomic graft placement, application of appropriate initial tension to the graft, use of fixation devices, and improved graft harvesting techniques.
Our experience with acute ACL injuries demonstrated the importance of a thorough physical examination and the need to tailor treatments to the patient, their specific pathology, and their commitment to rehabilitation. Nonoperative care can yield satisfactory results based on the patient"™s expected level of function and practitioners do not need to rush to reconstruct damaged ACLs. There still is a place for primary repair of the ACL today, although it is limited. Scaffolding and stenting are the key concepts, and whatever we can do to "regrow" or to encourage the ACL to heal is worthy of consideration. Research today is promising of more effective scaffolding as well as more efficient and effective surgery for ACL repair and replacement in active patients. We must work to integrate the connection between the patient, the knee, and the surgical technique to improve outcomes and provide the best treatments for our patients.
More controversy surrounds the treatment of an anterior cruciate ligament (ACL) tear than any other ligament injury in the body. The reason in part relates to the fact that no one approach has addressed and solved the problem of ACL insufficiency completely. An ideal graft would be one that provides as much strength as the native ACL, allows for secure fixation, has no harvest site morbidity, enables unrestricted rehabilitation, and restores normal knee biomechanics and kinematics. The best we can do at this point is provide tissue of sufficient strength using fixation methods that are relatively weak and inconsistent in an attempt to produce a graft that will see minimal strain in order to provide functional stability and minimize failure.
The management and surgical approach to anterior cruciate ligament (ACL) tears has dramatically evolved over the last 15 years. Advances in basic science, clinical studies of knee ligament pathophysiology, more precise diagnostic skills, and the use of magnetic resonance imaging have contributed to a heightened focus on the ACL. The increased emphasis on fitness and sports participation as well as the greater demand by recreational athletes for return to preinjury knee function have led to an increase in ACL surgery. In the United States, ACL injury rates have been reported to occur at 0.38 per 1,000 per year and it is estimated that over 75,000 ACL reconstructions are performed each year.1–3 As further attention is directed toward the ACL and the success of ACL surgery becomes more predictable, an increase in these numbers may be seen.
Seit 1979 haben wir zum Ersatz des vorderen Kreuzbandes das freie mittlere Drittel des Lig. patellae mit Knochenblöcken proximal und distal verwendet. Zusätzlich haben wir diese intraartikuläre Substitution durch eine extraartikuläre Verstärkungsplastik mittels Quadrizepssehne (entnommen in der Verlängerung des patellären Knochenblocks) ergänzt. Der im tibialen Bohrkanal liegende Knochenblock aus der Tuberositas tibiae wurde mit Metalldraht gegen eine tibiale Kortikalisschraube fixiert. Der patelläre Knochenblock wurde in einer tiefen suprakondylären Nut fixiert, deren Grund sich im anteromedialen Ansatzbereich des vorderen Kreuzbandes an der interkondylären Begrenzung des lateralen Femurkondylus befand. Die Quadrizepssehne wurde an ihrer Austrittsstelle aus dem lateralen Femurkondylus unter dem lateralen Seitenband nach ventral geführt, wo sie in leichter Außenrotation der Tibia in einem Knochenkanal des Tuberculum Gerdy (Tuberculum anterolaterale tibiae) verankert wurde. Postoperativ wurde das Kniegelenk früh mobilisiert. Die begründeten Vorteile dieser Rekonstruktionsmethode, die auf einer klinisch funktionellen und anatomischen Studie basieren, wurden durch verschiedene Studien belegt, die folgendes zeigten:
Das mittlere Drittel des Lig. patellae ist das stärkste z. Z. zur Verfügung stehende autologe Ersatzmaterial, das zu keiner namhaften Schwächung des verbleibenden Lig. patellae führt (Butler et al. 1979).
Das vollständige Herauslösen des distalen Knochenfragmentes, das allein die korrekte Plazierung des patellären Knochenblocks gegen die interkondyläre Begrenzung des lateralen Femurkondylus garantiert, wirkt sich im Vergleich zu einem distal gestielt belassenen Neoligament hinsichtlich der Revaskularisierung nicht ungünstig aus (Ginsburg et al. 1980; Scapinelli 1968).
Die Verankerung mittels Knochenblock ist allen anderen Fixationsmethoden überlegen, wobei der Fixation mittels Interferenzschraube im Knochenkanal der Vorzug gegeben wird (Lambert 1983; Kurosaka et al. 1983).
Dieser mechanische Vorteil wirkt sich nach 3 Monaten aus, da der Knochenblock dann knöchern im Kanal konsolidiert ist. Vom Knochenblock ausgehend wird durch progressives Einwachsen von Osteoid eine Osteointegration erreicht (Cabaud et al. 1974; Chambat et al. 1984; Clancy et al. 1981).
Aufgrund der guten mechanischen Fixation des Transplantates ist eine frühfunktionelle Nachbehandlung möglich, was sich positiv auf die Neoligamentbildung auswirkt (Burks et al. 1984; Noyes et al. 1983; Rigal et al. 1982).
Nach Ablauf eines Jahres erreicht die Neoligamentbildung bei einer ursprünglichen Transplantatbreite von 14 mm eine Reißfestigkeit, die mit dem normalen vorderen Kreuzband vergleichbar ist (Arnoczky et al.1982; Cabaud et al. 1974; Fayard et al. 1982; Clancy et al. 1981; Noyes et al. 1983). Unter Beachtung dieser Rekonstruktionsprinzipien scheint es logisch, diesen Eingriff unter Arthroskopiekontrolle zu versuchen, um die vordere Arthrotomie zu vermeiden und damit das Ausmaß der iatrogenen Schädigung zu verringern.
Die operative Versorgung der Ruptur des vorderen Kreuzbandes geht bereits auf das Jahr 1895 zurück. Damals wurde von Mayo Robson die erste überlieferte Kreuzbandnaht durchgeführt. Die ersten Kreuzbandplastiken wurden 1917 von Hey Groves und 1918 durch Alwyn Smith überliefert. Beide verwendeten einen Fascia-lata-Streifen. Zur selben Zeit wurden bereits Versuche unternommen, einen künstlichen Ersatz zu finden. Corner versuchte Drahtmaterialien, Alwyn Smith multiple Seidenfäden (Burnett u. Fowler 1985). Beiden Methoden war kein Erfolg beschieden. In den 20er Jahren wurden die ersten extraartikulären „repairs“ durchgeführt (Cotton, Morrison, Bosworth). Dabei fanden freie Fascia-lata-Streifen Verwendung. 1936 beschrieb Campbell die intraartikuläre Applikation von Lig.-patellae-Teilen. 1938 bestätigte Ivar Palmer bereits, daß Kreuzbandersatzoperationen schwierig, zeitraubend und riskant seien und daß sie meist nicht zu einer Restitutio ad integrum führten. Palmer entwickelte schon eine Bohrlehre zur präziseren Planierung des Transplantates. 1950 war es O’Donoghue, nach 1960 Jones, Slocum und Larson sowie Nicholas, die auf die Wichtigkeit des vorderen Kreuzbandes für die Stabilität des Knies hinwiesen. Schon 1918 empfahl Alwyn Smith Elektrostimulation zur Vermeidung der postoperativen Quadrizepsatrophie, Mauck empfahl einen Oberschenkelgips mit beweglicher Knieachse für die Nachbehandlung (zit. nach Burnett u. Fowler 1985).
Surgical technique, experimental viability testing, and long-term study of healing processes in the sheep compared with a free graft (microangiography, tensile testing).
Since 1979 we have used the free central one-third of the patellar tendon with proximal and distal bone blocks for reconstruction of the anterior cruciate ligament (ACL). We used to reinforce the intraarticular substitution by harvesting part of the quadriceps tendon in continuity with the patellar bone block. The tibial-tuberosity bone block was introduced into the tibial tunnel and anchored to a tibial cortex screw with a metal wire. The patellar bone block was fixed within a deep supracondylar slot whose base was in the anteromedial portion of the ACL attachment on the intercondylar aspect of the lateral femoral condyle. The quadriceps tendon emerging from the lateral femoral condyle was passed forward beneath the lateral collateral ligament and anchored in a tunnel in Gerdy’s tubercle with the tibia held in slight external rotation. The knee was mobilized early after surgery.
The surgical treatment of tears of the anterior cruciate ligament (ACL) dates from the year 1895, when Mayo Robson performed the first documented cruciate ligament repair. The first reconstructions of the ACL were described by Hey Groves in 1917 and by Alwyn Smith in 1918. Both replaced the ligament with a strip of fascia lata. Also at this time, initial attempts were made to develop a synthetic substitute. Corner tried strands of wire, while Alwyn Smith used multiple silk threads (Burnett and Fowler 1985). Neither method proved successful. The first extraarticular “repairs” were performed during the 1920s using free strips of fascia lata (Cotton, Morrison, Bosworth). In 1936 Campbell described the intraarticular use of patellar tendon grafts. As early as 1938, Ivar Palmer confirmed that cruciate ligament reconstructions were difficult, time-consuming, and risky and usually did not bring about a full recovery. At that time Palmer developed a drill guide for the more accurate placement of the graft.
This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the effects (benefits and harms) of different methods and devices for graft fixation in anterior cruciate ligament (ACL) reconstruction. In setting out our comparisons, we will group those relating to femoral fixation separately from those relating to tibial fixation. For femoral fixation, we will compare devices based on different mechanisms of fixation, the same mechanism of devices, new versus old, hardware-free versus hardware, and hybrid versus single. For tibial fixation, we will compare intratunnel versus extratunnel fixation devices, and different commonly-used devices. We will not include the comparison of bioabsorbable versus metallic interference screws, as this is covered in another Cochrane review (Debieux 2012).
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