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Anterior Cruciate Ligament (anterior + cruciate_ligament)
Terms modified by Anterior Cruciate Ligament Selected AbstractsImage-guided reconstruction of the anterior cruciate ligamentTHE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 1 2004J Sabczynski Abstract The replacement of the ruptured Anterior Cruciate Ligament (ACL) of the knee is a biomechanically difficult task. The correct placement of the graft, especially the isometry of the tibial and femoral insertion points, is critically to the success of the procedure. However, during arthroscopy, the planning of the insertion points and accurate execution of the plan is difficult. This paper reports an X-ray based system for navigation of the ACL graft implant. The system integrates arthroscopy and intra-operative X-ray imaging to identify the correct insertion points of the graft. Furthermore, it allows testing the isometry of these points before drilling of the femoral and tibial tunnel, and guides the drilling itself. Copyright © 2004 Robotic Publications Ltd. [source] The effect of skeletal maturity on the regenerative function of intrinsic ACL cellsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2010Ashley N. Mastrangelo Abstract Anterior cruciate ligament (ACL) injuries are an important clinical problem, particularly for adolescent patients. The effect of skeletal maturity on the potential for ACL healing is as yet unknown. In this study, we hypothesized that fibroblastic cells from the ACLs of skeletally immature animals would proliferate and migrate more quickly than cells from adolescent and adult animals. ACL tissue from skeletally immature, adolescent, and adult pigs and sheep were obtained and cells obtained using explant culture. Cell proliferation within a collagen,platelet scaffold was measured at days 2, 7, and 14 of culture using AM MTT assay. Cellular migration was measured at 4 and 24 h using a modified Boyden chamber assay, and cell outgrowth from the explants also measured at 1 week. ACL cells from skeletally immature animals had higher proliferation between 7 and 14 days (p,<,0.01 for all comparisons) and higher migration potential at all time points in both species (p,<,0.01 for all comparisons). ACL cells from skeletally immature animals have greater cellular proliferation and migration potential than cells from adolescent or adult animals. These experiments suggest that skeletal maturity may influence the biologic repair capacity of intrinsic ACL cells. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:644,651, 2010 [source] Periarticular ligament changes following ACL/MCL transection in an ovine stifle joint model of osteoarthritisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2007Yusei Funakoshi Abstract Anterior cruciate ligament (ACL) injuries often lead to significant functional impairment, and are associated with increased risk for induction of degenerative joint disease. However, few studies have described the effect of ligament transection on the remaining intact knee ligaments. This study sought to determine specifically what impact combined ACL/medial collateral ligament (MCL) transection had on the remaining intact knee ligaments, particularly from the histological, biochemical, and molecular perspectives. Twenty weeks post-ACL/MCL transection, the cut ends of sheep MCLs were bridged by scar, while the posterior cruciate ligaments (PCLs) and lateral collateral ligaments (LCLs) seemed gross morphologically normal. Water content and cell density increased significantly in the MCL scars and the intact PCLs but were unchanged in the LCLs. Collagen fibril diameter distribution was significantly altered in both MCL scar tissue and uninjured PCLs from transected joints. MMP-13 mRNA levels in MCL scars and PCLs from ligament transected joints were increased, while TIMP-1 mRNA levels were significantly decreased in the PCLs only. This study has shown that some intact ligaments in injured joints are impacted by the injury. The joint appears to behave like an integrated organ system, with injury to one component affecting the other components as the "organ" attempts to adapt to the loss of integrity. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:997,1006, 2007 [source] Mesenchymal stem cells derived from synovium, meniscus, anterior cruciate ligament, and articular chondrocytes share similar gene expression profilesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2009Yuko Segawa Abstract Mesenchymal stem cells (MSCs) can be obtained from various tissues, and contain common features. However, an increasing number of reports have described variant properties dependent of cell sources. We examined (1) whether MSCs existed in several intraarticular tissues, (2) whether gene expression profiles in intraarticular tissue MSCs closely resembled each other, and (3) whether identified genes were specific to intraarticular tissue MSCs. Human synovium, meniscus, intraarticular ligament, muscle, adipose tissue, and bone marrow were harvested, and colony-forming cells were analyzed. All these cells showed multipotentiality and surface markers typical of MSCs. Gene profiles of intraarticular tissue MSCs and chondrocytes were closer to each other than those of extraarticular tissues MSCs. Among three characteristic genes specific for intraarticular tissue MSCs, we focused on proline arginine-rich end leucine-rich repeat protein (PRELP). Higher expression of PRELP was confirmed in chondrocytes and intraarticular tissue MSCs among three elderly and three young donors. Synovium MSCs stably expressed PRELP, contrarily, bone marrow MSCs increased PRELP expression during in vitro chondrogenesis. In conclusion, MSCs could be isolated from various intraarticular tissues including meniscus and ligament, gene expression profiles of intraarticular tissue MSCs closely resembled each other, and the higher expression of PRELP was characteristic of intraarticular tissue MSCs. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 435,441, 2009 [source] Knee biomechanics after UKA and its relation to the ACL,a robotic investigationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006Jeremy F. Suggs Abstract Unicompartmental knee arthroplasty (UKA) has regained popularity in recent years. However, limited data exist on how UKA affects knee biomechanics. The role of the anterior cruciate ligament (ACL) after fixed bearing UKA remains controversial. In this study, a robotic testing system was used to apply a quadriceps/hamstrings load to cadaveric knee specimens in the intact state, after medial UKA, and after transection of the ACL in UKA. The load was applied to the knee from full extension to 120° of flexion in 30° increments. UKA generally did not affect anterior,posterior (AP) femoral position, but did cause external tibial rotation and variations in varus,valgus rotation compared to the intact knee. ACL transection after UKA shifted the femur posteriorly compared to the intact and UKA knees and increased internal tibial rotation compared to the UKA knee at low flexion. The AP motion of the articular contact position in the implant was increased after ACL transection. These data might help explain the mechanism of tibial component loosening and provide insight into further investigations of polyethylene wear in UKA. Based on the kinematic data, the ACL should be functional to provide patients the greatest opportunity for long-term success after medial UKA. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Medial collateral ligament insertion site and contact forces in the ACL-deficient kneeJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006Benjamin J. Ellis Abstract The objectives of this research were to determine the effects of anterior cruciate ligament (ACL) deficiency on medial collateral ligament (MCL) insertion site and contact forces during anterior tibial loading and valgus loading using a combined experimental-finite element (FE) approach. Our hypothesis was that ACL deficiency would increase MCL insertion site forces at the attachments to the tibia and femur and increase contact forces between the MCL and these bones. Six male knees were subjected to varus,valgus and anterior,posterior loading at flexion angles of ,0° and 30°. Three-dimensional joint kinematics and MCL strains were recorded during kinematic testing. Following testing, the MCL of each knee was removed to establish a stress-free reference configuration. An FE model of the femur,MCL,tibia complex was constructed for each knee to simulate valgus rotation and anterior translation at 0° and 30°, using subject-specific bone and ligament geometry and joint kinematics. A transversely isotropic hyperelastic material model with average material coefficients taken from a previous study was used to represent the MCL. Subject-specific MCL in situ strain distributions were used in each model. Insertion site and contact forces were determined from the FE analyses. FE predictions were validated by comparing MCL fiber strains to experimental measurements. The subject-specific FE predictions of MCL fiber stretch correlated well with the experimentally measured values (R2,=,0.95). ACL deficiency caused a significant increase in MCL insertion site and contact forces in response to anterior tibial loading. In contrast, ACL deficiency did not significantly increase MCL insertion site and contact forces in response to valgus loading, demonstrating that the ACL is not a restraint to valgus rotation in knees that have an intact MCL. When evaluating valgus laxity in the ACL-deficient knee, increased valgus laxity indicates a compromised MCL. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Acute botulinum toxin-induced muscle weakness in the anterior cruciate ligament-deficient rabbitJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2005David Longino Abstract We established botulinum type-A toxin (BTX-A) injections as a powerful tool to cause knee extensor weakness in New Zealand White (NZW) rabbits. The purpose of this study was to determine if BTX-A induced quadriceps weakness causes muscle dysfunction beyond that caused by anterior cruciate ligament (ACL) transection in the knee of NZW rabbits. Twenty animals were randomly divided into four study groups (n = 5 each); uninjected controls, BTX-A injection alone, ACL transection alone, BTX-A injection and ACL transection combined. Isometric knee extensor torque, quadriceps muscle mass, and vertical and anterior,posterior ground reaction forces were measured four weeks post single (BTX-A and ACL), unilateral intervention. Muscle weakness, muscle atrophy and decrease in ground reaction forces were all significantly greater for the experimental compared to the untreated contralateral legs. BTX-A injection produced a greater deficit in quadriceps mass and knee extensor torque than ACL transection alone, but produced smaller deficits in the ground reaction forces. ACL transection superimposed on BTX-A injection did not change either knee extensor torque production or muscle mass. Together these results suggest that BTX-A injection causes great force and muscle mass deficits, and affects functional gait in a significant manner, but it has no measurable functional effect when superimposed on ACL transection, at least not in the acute protocol tested here. Hopefully, BTX-A injection for acutely enhancing the degree of muscle weakness in otherwise untreated animals, or in experimental models of osteoarthritis, will help in investigating the role of muscle weakness in joint degeneration. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] A prospective analysis of incidence and severity of quadriceps inhibition in a consecutive sample of 100 patients with complete acute anterior cruciate ligament ruptureJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2004Terese L. Chmielewski Background: Weakness of the quadriceps femoris muscle after anterior cruciate ligament injury and reconstruction has been attributed to incomplete voluntary activation of the muscle. The literature is conflicting on the incidence of incomplete voluntary quadriceps activation after anterior cruciate ligament injury because of differences in testing methods and population biases. The purpose of this study was to systematically examine the incidence and severity of quadriceps voluntary activation failure in both lower extremities after acute anterior cruciate ligament injury. We hypothesized that the incidence of quadriceps inhibition would be higher in the anterior cruciate ligament injured limbs than the uninvolved limbs, that the incidence of inhibition in the anterior cruciate ligament deficient limbs would be larger than in our historical sample of healthy young individuals tested in the same manner and that there would be no difference in inhibition by gender. Study design: Prospective, descriptive. Methods: One hundred consecutive patients with acute anterior cruciate ligament rupture (39 women and 61 men) were tested when range of motion was restored and effusion resolved, an average of 6 weeks after injury. A burst superimposition technique was used to assess quadriceps muscle activation and strength in all patients. Dependent t -tests were used to compare side-to-side differences in quadriceps strength. Independent t -tests were used to compare incidence of activation failure by gender and make comparisons to historical data on young, active individuals. Results: The average involved side quadriceps activation was 0.92, and ranged from 0.60 to 1.00. The incidence of incomplete activation in the involved side quadriceps was 33 per cent and uninvolved side quadriceps was 31 per cent after acute anterior cruciate ligament rupture. The incidence of incomplete activation bilaterally was 21 per cent. There was no difference in incidence of quadriceps inhibition by gender. Conclusion: The incidence of voluntary quadriceps inhibition on the involved side was three times that of uninjured, active young subjects, but the magnitude was not large. The incidence of quadriceps inhibition on the uninjured side was similar to the injured side. Clinical relevance: Both the incidence and magnitude of quadriceps inhibition after ACL rupture are lower than have previously been reported. The conventional wisdom, therefore, that quadriceps inhibition is a significant problem in this population is challenged by the results of this study. Differences between this study and others include sufficient practice to ensure a maximal effort contraction and rigorous inclusion criteria. The findings have implications for strength testing as well as rehabilitation. The quadriceps index, an assessment of the injured side quadriceps strength deficit may be affected by the presence of voluntary activation failure in the uninvolved side. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Distribution of in situ forces in the anterior cruciate ligament in response to rotatory loadsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2004Mary T. Gabriel Abstract The anterior cruciate ligament (ACL) can be anatomically divided into anteromedial (AM) and posterolateral (PL) bundles. Current ACL reconstruction techniques focus primarily on reproducing the AM bundle, but are insufficient in response to rotatory loads. The objective of this study was to determine the distribution of in situ force between the two bundles when the knee is subjected to anterior tibial and rotatory loads. Ten cadaveric knees (50 ± 10 years) were tested using a robotic/universal forcemoment sensor (UFS) testing system. Two external loading conditions were applied: a 134 N anterior tibial load at full knee extension and 15°, 30°, 60°, and 90° of flexion and a combined rotatory load of 10 N m valgus and 5 N m internal tibial torque at 15° and 30° of flexion. The resulting 6 degrees of freedom kinematics of the knee and the in situ forces in the ACL and its two bundles were determined. Under an anterior tibial load, the in situ force in the PL bundle was the highest at full extension (67 ± 30 N) and decreased with increasing flexion. The in situ force in the AM bundle was lower than in the PL bundle at full extension, but increased with increasing flexion, reaching a maximum (90 ± 17 N) at 60° of flexion and then decreasing at 90°. Under a combined rotatory load, the in situ force of the PL bundle was higher at 15° (21 ± 11 N) and lower at 30° of flexion (14 ± 6 N). The in situ force in the AM bundle was similar at 15° and 30° of knee flexion (30 ± 15 vs. 35 ± 16 N, respectively). Comparing these two external loading conditions demonstrated the importance of the PL bundle, especially when the knee is near full extension. These findings provide a better understanding of the function of the two bundles of the ACL and could serve as a basis for future considerations of surgical reconstruction in the replacement of the ACL. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Electromyographic analysis of a modified maneuver for quadriceps femoris muscle setting with co-contraction of the hamstringsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2003Masaaki Nakajima Abstract A ,quadriceps femoris muscle setting" is isometric quadriceps femoris exercise which can be widely used in early knee rehabilitation. However this exercise cannot obtain enough co-contraction of the hamstrings. Isolated quadriceps femoris contraction in knee extension imposes severe strain to anterior cruciate ligament. We succeeded in developing a simple training maneuver that is effective in obtaining co-contraction of the hamstrings,a modified maneuver for the quadriceps femoris muscle setting with the contralateral lower limb raised (MQS). In this study, we analyzed the effect of this maneuver by EMG quantification. Twenty-eight healthy young adult men performed sequential trials consisting of normal quadriceps femoris muscle setting (NQS) and MQS. Electromyographic activity was recorded from surface electrodes on the gluteus maximus, vastus medialis, rectus femoris, vastus lateralis, semitendinosus and biceps femoris (long head), and normalized to values derived from maximal isometric trials. The % maximal voluntary isometric contraction (%MVIC) of the vastus medialis, vastus lateralis and rectus femoris did not vary in the each maneuver. However, the %MVIC of the hamstrings varied significantly in the MQS. This study suggests that effective co-contraction of the hamstrings can be obtained in MQS by adjusting the load to the raised lower limb. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] The effects of graft width and graft laxity on the outcome of caprine anterior cruciate ligament reconstructionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2002J. F. Cummings We studied how initial graft size and initial graft laxity affected the biomechanics of anterior cruciate ligament (ACL) reconstruction at six months. Sixteen goats had bilateral reconstructions staged eight weeks apart. Autografts 4 and 7 mm wide were taken from the central patellar tendon (PT). Lax grafts were created by adding 4 mm slack to the graft before fixing. We reconstructed each joint using a combination of width and laxity treatments. Both factors were changed for the contralateral joint and all combinations appeared with equal frequency. At six months we measured the joint extension limit, anterior,posterior (AP) translation, and osteoarthritic changes. The grafts were then tested to failure to determine their mechanical properties. After six months the difference in initial treatments had disappeared: there was no difference in graft cross-section due to the different initial widths and there was no difference in joint AP translation due to the initial graft laxity. We did observe that wide grafts were associated with a block to extension, decreased joint AP translation, and increased articular cartilage damage and osteophyte formation. While AP translation was reduced, it was correlated with decreased extension, possibly indicating an increase in scar tissue formation rather than a more functional graft. Neither graft width nor graft laxity produced differences in any graft mechanical properties. This suggests that the use of larger grafts to prevent increased AP translation has undesirable complications. Ultimately, we conclude that neither of these surgical treatments strongly affects the biomechanical result of caprine ACL reconstruction. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Ultrastructural findings after intraarticular application of hyaluronan in a canine model of arthropathyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2000W. Wenz We investigated the effect of intraarticularly applied hyaluronic acid (hyaluronan) on the cartilaginous structure of experimentally induced chondromalacia patellae in dogs. For the induction of chondromalacia, we used the Pond-Nuki technique, which involved severance and resection of the anterior cruciate ligament, as a canine model of arthropathy in 27 foxhounds (three groups of nine animals each). In a pilot study, we evaluated the effect of resection of the anterior cruciate ligament with no therapy. Patellar specimens were retrieved at 3, 6, and 12 weeks postoperatively. Subsequently, we compared a treatment group that received intraarticular injections of hyaluronan with a placebo group that received saline solution. The groups were compared at 3, 6, and 12 weeks postoperatively. Three animals from the treatment and placebo groups received five injections of hyaluronan during one of the 4-week intervals (weeks 3,6, 6,9, or 12,15). Specimens were retrieved 5 weeks after the last injection. In both groups, the uninvolved contralateral knee served as a control. The specimens were taken from the medial and lateral patellar poles. Histological analysis included light microscopy and transmission electron microscopy. The structural and ultrastructural changes were assessed qualitatively and were quantified with use of a modified Mankin score. Our results indicate that chondromalacia patellae may be induced with the Pond-Nuki technique. We found a significant reduction (p < 0.01) of cartilaginous lesions in the hyaluronan group compared with the placebo group. Our results suggest that intraarticularly applied hyaluronan is effective in delaying the degenerative process of cartilage degradation. Therefore, we conclude that the use of hyaluronan may be indicated during the early stages of chondromalacia. [source] Hamstrings and iliotibial band forces affect knee kinematics and contact patternJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2000S. D. Kwak Many clinical studies have emphasized the role of the hamstrings and the iliotibial band on knee mechanics, although few biomechanical studies have investigated it. This study therefore examined two hypotheses: (a) with loading of the hamstrings, the tibia translates posteriorly and rotates externally and the tibial contact pattern shifts anteriorly; furthermore, the changes in tibial kinematics alter patellar kinematics and contact; and (b) loading the iliotibial band alters the kinematics and contact pattern of the tibiofemoral joint similarly to loading the hamstrings, and loading the iliotibial band laterally translates the patella and its contact location. Five cadaveric knee specimens were tested with a specially designed knee-joint testing machine in an open-chain configuration. At various flexion angles, the knees were tested always with a quadriceps force but with and without a hamstrings force and with and without an iliotibial band force. The results support the first hypothesis. Hence, the hamstrings may be important anterior and rotational stabilizers of the tibia, a role similar to that of the anterior cruciate ligament. The results also support the second hypothesis, although the iliotibial band force had a smaller effect on the tibia than did the hamstrings force. Both forces also changed patellar kinematics and contact, demonstrating that these structures should also be considered during the clinical management of patellar disorders. [source] Enamel matrix derivative enhances tissue formation around scaffolds used for tissue engineering of ligamentsJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 2 2010Michael P. Messenger Abstract The following in vitro translational study investigated whether enamel matrix derivative (EMD), an approved biomimetic treatment for periodontal disease (Emdogain®) and hard-to-heal wounds (Xelma®), enhanced synovial cell colonization and protein synthesis around a scaffold used clinically for in situ tissue engineering of the torn anterior cruciate ligament (ACL). Synovial cells were enzymatically extracted from bovine synovium and dynamically seeded onto polyethylene terephthalate (PET) scaffolds. The cells were cultured in low-serum medium (0.5% FBS) for 4 weeks with either a single administration of EMD at the start of the 4 week period or multiple administrations of EMD at regular intervals throughout the 4 weeks. Samples were harvested and evaluated using the Hoechst DNA assay, BCA protein assay, cresolphthalein complexone calcium assay, SDS,PAGE, ELISA and electron microscopy. A significant increase in cell number (DNA) (p < 0.01), protein content (p < 0.01) and TGF,1 synthesis (p < 0.01) was observed with multiple administrations of EMD. Additionally, SDS,PAGE showed an increase in high molecular weight proteins, characteristic of the fibril-forming collagens. Electron microscopy supported these findings, showing that scaffolds treated with multiple administrations of EMD were heavily coated with cells and extracellular matrix (ECM) that enveloped the fibres. Multiple administrations of EMD to synovial cell-seeded scaffolds enhanced the formation of tissue in vitro. Additionally, it was shown that EMD enhanced TGF,1 synthesis of synovial cells, suggesting a potential mode of action for EMD's capacity to stimulate tissue regeneration. Copyright © 2009 John Wiley & Sons, Ltd. [source] A case of fatal anaphylaxis in a dog associated with a dexamethasone suppression testJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 3 2005DACVECC, DACVIM, Michael Schaer DVM Abstract Objective: To describe a case of fatal anaphylaxis in a dog associated with a ,routine' dexamethasone suppression test. Case summary: An 8-year-old, spayed female dog, was treated with parenteral dexamethasone for a diagnosis of immune-mediated thrombocytopenia. The dog had responded to treatment, but 9 months later was evaluated for endogenous hyperadrenocorticism, prior to surgery for a ruptured anterior cruciate ligament. A normal ACTH stimulation test was followed by a high-dose dexamethasone suppression test. Immediately following the intravenous injection of dexamethasone, the dog developed severe anaphylactic shock and died. The postmortem examination findings supported the diagnosis of anaphylaxis. New information provided: The anaphylaxis in this dog was fulminating and by-passed the usual early signs of drug hypersensitivity. This is the first case in the veterinary literature reporting on dexamethasone as the cause of this dog's catastrophic event. [source] Knee pain in the ACL-deficient osteoarthritic knee and its relationship to quality of lifePHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 2 2003Michael Hartwick Abstract Background and Purpose Pain during activities of daily living is a common presenting complaint of individuals with knee osteoarthritis and anterior cruciate ligament injury. Knee pain is also associated with a decrease in quality of life for people with osteoarthritis. The purpose of the present study was to examine the dose,response relationship between knee joint forces and painful symptoms, and whether the acute symptoms, were associated with individuals' quality of life. Method This was a cross-sectional cohort correlation study. Seventeen individuals with anterior cruciate ligament (ACL)-deficient knees diagnosed with ipsilateral knee osteoarthritis completed the ACL quality of life questionnaire (ACL-QOL). The subjects also rated pain associated with each of five incremental isometric knee extension tests, proportional to their body weight. Analysis of variance was used to assess the association between pain and normalized torque. Linear regression was used to assess the correlation between the ACL-QOL score and the total pain experienced during the graded test. Results A strong relationship was found between the level of perceived knee pain and the amount of isometric torque produced (Pearson's r = 0.98; p<0.001). There was a statistically significant relationship between pain during the graded isometric test and the ACL-QOL (Pearson's r = ,0.56; p = 0.016). Conclusions Since knee joint compression is a function of active isometric knee extension torque, increased painful symptoms were associated with increased compression forces at the knee joint for these subjects. The relationship between pain provocation and disease-specific quality of life provides evidence for the proposed joint provocation test for this subject population. Weakness caused by osteoarthritis (OA) may, in part, be a negative conditioning response that would need to be overcome in rehabilitation. Copyright © 2003 Whurr Publishers Ltd. [source] Image-guided reconstruction of the anterior cruciate ligamentTHE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 1 2004J Sabczynski Abstract The replacement of the ruptured Anterior Cruciate Ligament (ACL) of the knee is a biomechanically difficult task. The correct placement of the graft, especially the isometry of the tibial and femoral insertion points, is critically to the success of the procedure. However, during arthroscopy, the planning of the insertion points and accurate execution of the plan is difficult. This paper reports an X-ray based system for navigation of the ACL graft implant. The system integrates arthroscopy and intra-operative X-ray imaging to identify the correct insertion points of the graft. Furthermore, it allows testing the isometry of these points before drilling of the femoral and tibial tunnel, and guides the drilling itself. Copyright © 2004 Robotic Publications Ltd. [source] Prospective randomized comparison of endobutton versus cross-pin femoral fixation in hamstring anterior cruciate ligament reconstruction with 2-year follow-upANZ JOURNAL OF SURGERY, Issue 3 2010Rohan Price Abstract Background:, To determine if there is a different clinical outcome after TransFix versus endobutton femoral fixation in hamstring anterior cruciate ligament (ACL) reconstruction. Methods:, Twenty-nine patients were randomized into either Endobutton (Smith & Nephew, Andover, MA, USA) (n= 13) or TransFix (Arthrex, Naples, FL, USA) (n= 16) femoral fixation in hamstring ACL reconstruction. The distal fixation was with a bioabsorbable interference screw. The evaluation methods were clinical history and examination, KT1000 arthrometry for laxity as well as the International Knee Documentation Committee (IKDC) scores over a 2-year time frame. Results:, There were no significant differences between the study groups preoperatively. For the 2-year follow-up, 11 patients in the Endobutton group and 13 patients in the TransFix group were available (greater than 80%). No statistical differences between the two groups were found at the 1- or 2-year follow-up examinations. At the 2-year follow-up, 72.7% of the Endobutton and 84.6% of the TransFix group patients were in the IKDC A or B categories. Additional procedures postoperatively occurred more frequently in the TransFix group. Conclusions:, There were no significant differences in the results for either technique of femoral fixation. Level of Evidence:, Level I. [source] Prevention of cartilage degeneration and restoration of chondroprotection by lubricin tribosupplementation in the rat following anterior cruciate ligament transectionARTHRITIS & RHEUMATISM, Issue 8 2010Gregory D. Jay Objective To investigate whether cartilage degeneration is prevented or minimized following intraarticular injections of lubricin derived from human synoviocytes in culture, recombinant human PRG4 (rhPRG4), or human synovial fluid (SF) in a rat model of anterior cruciate ligament (ACL) injury. Methods Unilateral ACL transection (ACLT) was performed in Lewis rats (n = 45). Nine animals were left untreated. The remaining rats were given intraarticular injections (50 ,l/injection) of either phosphate buffered saline (PBS) (n = 9), human synoviocyte lubricin (200 ,g/ml; n = 9), rhPRG4 (200 ,g/ml; n = 9), or human SF lubricin (200 ,g/ml; n = 9) twice weekly beginning on day 7 after injury. Joints were harvested on day 32 after injury. Histologic analysis was performed using Safranin O,fast green staining, and articular cartilage degeneration was graded using the Osteoarthritis Research Society International (OARSI),modified Mankin criteria. Histologic specimens were immunoprobed for lubricin and sulfated glycosaminoglycans. A 24-hour urine collection was performed on days 17 and 29 postinjury, and urinary C-terminal telopeptide of type II collagen (CTX-II) levels were measured. Results Treatment with human synoviocyte lubricin resulted in significantly lower OARSI scores for cartilage degeneration compared with no treatment or PBS treatment (P < 0.05). Increased immunostaining for lubricin in the superficial zone chondrocytes and on the surface of cartilage was observed in lubricin-treated, but not untreated or PBS-treated, joints. On day 17, urinary CTX-II levels in human synoviocyte lubricin, and human SF lubricin,treated animals were significantly lower than those in untreated animals (P = 0.005 and P = 0.002, respectively) and in PBS-treated animals (P = 0.002 and P < 0.001, respectively). Conclusion After treatment with any of the 3 types of lubricin evaluated in this study, a reduction in cartilage damage following ACLT was evident, combined with a reduction in type II collagen degradation. Our findings indicate that intraarticular lubricin injection following an ACL injury may be beneficial in retarding the degeneration of cartilage and the development of posttraumatic OA. [source] Increased tibiofemoral cartilage contact deformation in patients with anterior cruciate ligament deficiencyARTHRITIS & RHEUMATISM, Issue 12 2009Samuel K. Van de Velde Objective To investigate the in vivo cartilage contact biomechanics of the tibiofemoral joint following anterior cruciate ligament (ACL) injury. Methods Eight patients with an isolated ACL injury in 1 knee, with the contralateral side intact, participated in the study. Both knees were imaged using a specific magnetic resonance sequence to create 3-dimensional models of knee bone and cartilage. Next, each patient performed a lunge motion from 0° to 90° of flexion as images were recorded with a dual fluoroscopic system. The three-dimensional knee models and fluoroscopic images were used to reproduce the in vivo knee position at each flexion angle. With this series of knee models, the location of the tibiofemoral cartilage contact, size of the contact area, cartilage thickness at the contact area, and magnitude of the cartilage contact deformation were compared between intact and ACL-deficient knees. Results Rupture of the ACL changed the cartilage contact biomechanics between 0° and 60° of flexion in the medial compartment of the knee. Compared with the contralateral knee, the location of peak cartilage contact deformation on the tibial plateaus was more posterior and lateral, the contact area was smaller, the average cartilage thickness at the tibial cartilage contact area was thinner, and the resultant magnitude of cartilage contact deformation was increased. Similar changes were observed in the lateral compartment, with increased cartilage contact deformation from 0° to 30° of knee flexion in the presence of ACL deficiency. Conclusion ACL deficiency alters the in vivo cartilage contact biomechanics by shifting the contact location to smaller regions of thinner cartilage and by increasing the magnitude of the cartilage contact deformation. [source] Central bone marrow lesions in symptomatic knee osteoarthritis and their relationship to anterior cruciate ligament tears and cartilage lossARTHRITIS & RHEUMATISM, Issue 1 2008Gabriela Hernández-Molina Objective Medial and lateral compartment bone marrow lesions (BMLs) have been tied to cartilage loss. We undertook this study to assess 2 types of BMLs in the central region of the knee (type 1 BMLs, which are related anatomically to anterior cruciate ligament [ACL]/posterior cruciate ligament [PCL] insertions, and type 2 BMLs, which encompass both the central region and either the medial or the lateral compartment) and determine their relationship to cartilage loss and ACL tears. Methods Magnetic resonance imaging (MRI) of the knee was performed at baseline and at followup (15 and/or 30 months) in 258 subjects with symptomatic osteoarthritis (OA). At baseline, we assessed ACL tears and central BMLs located at or between the tibial spines or adjacent to the femoral notch. Cartilage loss was present if the score in any region of the tibiofemoral joint increased by ,1 units at the last available followup, using a modified Whole-Organ MRI Score. We used logistic regression adjusted for alignment, body mass index, Kellgren/Lawrence score, sex, and age. Results One hundred thirty-nine knees (53.8%) had central BMLs, of which 129 had type 1 BMLs (96 abutted the ACL and had no coexistent type 2 features) and 25 had type 2 BMLs (often overlapped with type 1). Type 1 lesions were associated with ACL tears (odds ratio [OR] 5.9, 95% confidence interval [95% CI] 2.2,16.2) but not with cartilage loss (OR 1.6, 95% CI 0.8,3.1), while medial type 2 BMLs were related to medial cartilage loss (OR 6.1, 95% CI 1.0,35.2). Conclusion Central BMLs that abutted the ACL were highly prevalent and strongly related to ACL pathology, suggesting a role of enthesopathy in OA. Only BMLs with medial extension were related to ipsilateral cartilage loss. [source] In vivo selective inhibition of mitogen-activated protein kinase kinase 1/2 in rabbit experimental osteoarthritis is associated with a reduction in the development of structural changesARTHRITIS & RHEUMATISM, Issue 6 2003Jean-Pierre Pelletier Objective The primary aim of this study was to investigate, using an experimental rabbit model of osteoarthritis (OA), the effect of a selective mitogen-activated protein kinase kinase 1/2 (MEK-1/2) inhibitor, PD 198306, on the development of structural changes. Additional aims were to assess the effects of the inhibitor on levels of phosphorylated extracellular signal,regulated kinase 1/2 (phospho,ERK-1/2) and matrix metalloproteinase 1 (MMP-1; collagenase 1) in OA chondrocytes. Methods After surgical sectioning of the anterior cruciate ligament of the right knee joint, rabbits with OA were separated into 3 experimental groups: oral treatment with placebo or with PD 198306 at a therapeutic concentration of 10 mg/kg/day or 30 mg/kg/day. Each treatment started immediately after surgery. The animals were killed 8 weeks after surgery. Macroscopic and histologic studies were performed on the cartilage and synovial membrane. The levels of phospho,ERK-1/2 and MMP-1 in OA cartilage chondrocytes were evaluated by immunohistochemistry. Normal, untreated rabbits were used as controls. Results OA rabbits treated with the highest dosage of MEK-1/2 inhibitor showed decreases in the surface area (size) of cartilage macroscopic lesions (P < 0.002) and in osteophyte width on the lateral condyles (P = 0.05). Histologically, the severity of synovial inflammation (villous hyperplasia) was also reduced (P < 0.02). In cartilage from placebo-treated OA rabbits, a significantly higher percentage of chondrocytes in the superficial layer stained positive for phospho,ERK-1/2 and MMP-1 compared with normal controls. Rabbits treated with the highest dosage of PD 198306 demonstrated a significant and dose-dependent reduction in the level of phospho,ERK-1/2 and a lower level of MMP-1. Conclusion This study demonstrates that, in vivo, PD 198306, a selective inhibitor of MEK-1/2, can partially decrease the development of some of the structural changes in experimental OA. This effect was associated with a reduction in the level of phospho,ERK-1/2 in OA chondrocytes, which probably explains the action of the drug. [source] Anterior Cruciate Ligament Reconstruction Using Chitin-coated Fabrics in a Rabbit ModelARTIFICIAL ORGANS, Issue 1 2010Tomoyuki Kawai Abstract Experimental anterior cruciate ligament (ACL) reconstruction was carried out in a rabbit model, in which a chitin-coated polyester graft was used as the scaffold, and a noncoated graft was used as a control graft. After 8 weeks implantation, a mechanical test of the knee and histometric measurement of the graft and surrounding tissues were carried out. A tensile test of the femur-graft-tibia specimen showed that the knee treated with the coated graft had a peak resistance force of 42.2 ± 12.7 N, which was significantly greater than the 19.2 ± 15.3 N of the knee treated with the control graft. The histometric measurement revealed that the area of bone tissue within the section of the coated graft in the femoral bone tunnel was 3.43 ± 1.73 mm2, which was significantly greater than the area of 0.29 ± 0.37 mm2 of the control graft. Similarly, the area of soft tissue within and around the midsubstance of the coated graft located in the articular cavity was significantly greater than that of the control graft. The chitin coating enhanced the formation of bone tissue in the femoral bone tunnel and soft tissue in the articular cavity, and increased the attachment strength of the graft to the bone. Thus, the efficacy of the chitin coating for the ACL reconstruction scaffolds was demonstrated. [source] Designing a Three-dimensional Expanded Polytetrafluoroethylene,Poly(lactic-co-glycolic acid) Scaffold for Tissue EngineeringARTIFICIAL ORGANS, Issue 4 2009Hung-Jen Shao Abstract:, The purpose of this study was to design a three-dimensional expanded polytetrafluoroethylene (ePTFE),poly(lactic-co-glycolic acid) (PLGA) scaffold for tissue engineering. To test the feasibility of this composite scaffold, a series of two-dimensional culture experiments were performed to investigate the behavior of anterior cruciate ligament (ACL) cells on the ePTFE and PLGA membranes. It was found PLGA provided a cell-favorable substrate for cell adhesion, migration, and growth, indicating PLGA is an ACL cell-conductive material. Conversely, poor adhesion and proliferation of ACL cells were observed on the ePTFE, even on the collagen-coated ePTFE. Therefore, the scaffold was not fabricated by coating PLGA on the ePTFE surface because it is difficult to coat anything on the extremely hydrophobic ePTFE surface. Instead, the ePTFE embedded in the PLGA matrix was prepared by immersing ePTFE scrim yarns into the PLGA solution, and then precipitating PLGA to form a three-dimensional construction with porous morphology. The role of ePTFE is regarded as a reinforcing constituent to improve the mechanical strength of porous PLGA matrix to provide early repair strength for tissue healing. However, porous PLGA matrix acts as a supportive environment for allowing cell adhesion, migration, and growth to guide the repair and regeneration of ligament tissue. To test this assumption, a preliminary animal experiment of rabbit ACL wound healing with this three-dimensional ePTFE,PLGA scaffold was performed. These results are very encouraging because such a new scaffold made of ePTFE scrim yarns embedded in PLGA may serve as ACL prostheses in the ligament tissue engineering. [source] Double-bundle reconstruction of the anterior cruciate ligamentAUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 1 2007Thomas Nau Abstract Injuries of the anterior cruciate ligament often present in rural practices and rural regional hospitals. Surgical reconstruction is the treatment of choice in the young and active patient. Better biomechanical understanding has led to a further improvement of the surgical technique. The double-bundle reconstruction, which aims to address both functional bundles of the anterior cruciate ligament, represents the latest development in this field. In this review article the basic biomechanical principles as well as a new surgical technique are presented for practitioners in rural practice and rural regional hospitals. [source] Effect of homeopathy on analgesic intake following knee ligament reconstruction: a phase III monocentre randomized placebo controlled studyBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 2 2008A. Paris What is already known about this subject ,,The efficacy of homeopathy is still under debate and a recent meta-analysis recommended further randomized double-blind clinical trials to identify any clinical situation in which homeopathy might be effective. What this study adds ,,The complex of homeopathy tested in this study (Arnica montana 5 CH, Bryonia alba 5 CH, Hypericum perforatum 5 CH and Ruta graveolens 3 DH) is not superior to placebo in reducing 24 h morphine consumption after knee ligament reconstruction. Aims The efficacy of homeopathy is still under debate. The objective of this study was to assess the efficacy of homeopathic treatment (Arnica montana 5 CH, Bryonia alba 5 CH, Hypericum perforatum 5 CH and Ruta graveolens 3 DH) on cumulated morphine intake delivered by PCA over 24 h after knee ligament reconstruction. Methods This was an add-on randomized controlled study with three parallel groups: a double-blind homeopathic or placebo arm and an open-label noninterventional control arm. Eligible patients were 18,60 years old candidates for surgery of the anterior cruciate ligament. Treatment was administered the evening before surgery and continued for 3 days. The primary end-point was cumulated morphine intake delivered by PCA during the first 24 h inferior or superior/equal to 10 mg day,1. Results One hundred and fifty-eight patients were randomized (66 in the placebo arm, 67 in the homeopathic arm and 25 in the noninterventional group). There was no difference between the treated and the placebo group for primary end-point (mean (95% CI) 48% (35.8, 56.3), and 56% (43.7, 68.3), required less than 10 mg day,1 of morphine in each group, respectively). The homeopathy treatment had no effect on morphine intake between 24 and 72 h or on the visual analogue pain scale, or on quality of life assessed by the SF-36 questionnaire. In addition, these parameters were not different in patients enrolled in the open-label noninterventional control arm. Conclusions The complex of homeopathy tested in this study was not superior to placebo in reducing 24 h morphine consumption after knee ligament reconstruction. [source] | ||||||||||