Knee Squeaking in Native Joint after Anterior Cruciate Ligament Reconstruction

Articular squeaking sounds cause discomfort, frustration, and embarrassment for affected patients, especially in social contexts. Postsurgical native knee squeaking is rare, and only limited data on the subject are available in the literature. This study presents a case of knee squeaking after anterior cruciate ligament (ACL) reconstruction. A 22-year-old woman underwent reconstructive ACL surgery for an isolated tear in her right knee using an outside-in bone-patellar tendon-bone technique. Two months after the surgery, squeaking sound at knee flexion in both weight-bearing and non-weight-bearing conditions appeared without any further symptoms. The audible squeaking sound was a source of frustration and embarrassment for the patient. Given the unsuccessful attempts at diagnostic imaging, a diagnostic arthroscopy was performed during which a multistrand, long-chain, ultra-high molecular weight polyethylene suture was found moving freely in the joint. This suture, originally attached to the patellar bone portion of the graft, was removed during the arthroscopy. After the procedure, the patient reported having no more knee squeaking sound episodes. Friction of a nonabsorbable suture between the cartilage of a femoral condyle and a tibial plateau can produce a characteristic articular high-pitch squeaking sound. This should alert the surgeon to the possible presence of a freely moving fixation material in the knee. Diagnosis is clinical, as diagnostic imaging techniques have poor sensitivity.

Clinical and quality-of-life outcomes of a combined synthetic scaffold and autogenous tissue graft procedure for articular cartilage repair in the knee

Background

Injuries to the articular cartilage of the knee often fail to heal properly due to the hypocellular and avascular nature of this tissue. Subsequent disability can limit participation in sports and decrease quality of life. Subchondral bone perforations are used for the treatment of small defects. Filling out the central portion in larger lesions becomes difficult, and scaffolds can be used as adjuvants, providing a matrix onto which the defect can be filled in completely. Also, autogenous cartilage grafts can be combined, acting as an inducer and improving healing quality, all in a single procedure.

Methods

This observational study evaluated the clinical and quality-of-life outcomes of patients with articular cartilage lesions of the knee undergoing repair via a microfracture technique combined with a synthetic scaffold and autogenous cartilage graft, with transosseous sutures and fibrin glue fixation, at 12 months of follow-up. Secondarily, it assessed whether combined procedures, previous surgical intervention, traumatic aetiology, lesion location, and age affect outcomes. The sample consisted of adult patients (age 18–66 years) with symptoms consistent with chondral or osteochondral lesions, isolated or multiple, ICRS grade III/IV, 2–12 cm² in size. Patients with corrected angular deviations or instabilities were included. Those with BMI > 40 kg/m², prior total or subtotal (> 30%) meniscectomy, second-look procedures, and follow-up < 6 months were excluded. Pain (VAS), physical activity (IKDC), osteoarthritis (WOMAC), and general quality of life (SF-36) were assessed.

Results

64 procedures were included, comprising 60 patients. There was significant improvement (P < 0.05) in VAS score (5.92–2.37), IKDC score (33.44–56.33), and modified WOMAC score (53.26–75.93) after surgery. The SF-36 showed significant improvements in the physical and mental domains (30.49–40.23 and 46.43–49.84 respectively; both P < 0.05).

Conclusions

Combination of microfractures, autogenous crushed cartilage graft, synthetic scaffold, and transosseous sutures with fibrin glue provides secure fixation for treatment of articular cartilage lesions of the knee. At 12-month follow-up, function had improved by 20 points on the IKDC and WOMAC, and quality of life, by 10 points on the SF-36. Age > 45 years had a negative impact on outcomes.

Rationale, study design, and descriptive data of the Lucky Bone™ Fracture Liaison Service

The study design of a multidisciplinary Fracture Liaison Service (2-year follow-up) aiming to optimize fragility fracture management in an outpatient setting is presented. Patient characteristics, investigation, and treatment initiation data at baseline were recorded. Results corroborate the care gap in osteoporosis management, reinforcing the need for secondary fracture prevention programs.

PURPOSE

This paper describes the study design, implementation, and baseline characteristics of a multidisciplinary Fracture Liaison Service (FLS) in Quebec (Canada).

METHODS

A FLS was implemented as a prospective cohort study. After identification, fracture risk was assessed and patients were started on treatment or referred, according to guidelines and risk assessment. Thereafter, patients were systematically followed over 2 years. Clinical data (fractures, bone density, blood testing (bone turnover markers), quality of life, physical disability) as well as administrative data (pharmacological, health services, hospitalization) was collected. Baseline descriptive data was analyzed and presented.

RESULTS

Of 542 recruited participants, 532 underwent baseline assessment (85.7% female, mean age 63.4 years). Overall, 29.7% of participants either withdrew from the study or were lost to follow-up. Almost 27% were referred to a specialist, while > 70% received anti-osteoporosis medication prescriptions through the FLS at baseline. Mean femoral T-score was - 1.6 ± 1.0 and vertebral T-score was - 1.7 ± 1.4. Nearly 19% of subjects reported being under anti-osteoporosis medication at the time of incident fracture. Thirty-three percent of participants reported a prior fracture history, of which 29.7% reported being given anti-osteoporosis therapy. Most fracture sites were to the wrist and ankle, while < 19% were hip/femur or vertebral fractures.

CONCLUSIONS

These results highlight the important care gap in fragility fracture management and reinforce the need for secondary fracture prevention programs. This prospective study will allow the evaluation of key performance indicators for outpatient clinic-based FLS, such as medication usage, by combining prospective clinical and administrative data.

LARS synthetic ligaments for the acute management of 111 acute knee dislocations: effective surgical treatment for most ligaments

PURPOSE

The purpose of this study was to describe the longitudinal outcomes of acute repair and augmentation for the reconstruction of dislocated knees, using LARS synthetic ligaments.

METHODS

Patients with a knee dislocation surgically treated using LARS synthetic ligament augmentation, with a minimum follow-up of 24 months, were enrolled between 1996 and 2014. Range of motion, Lachman, pivot shift, posterior drawer, step off sign, valgus, varus, KT-1000 arthrometer, Telos technique, IKDC, Lysholm, Tegner, and Meyers scores were obtained every 2 years up to 10 years.

RESULTS

Median age was 32.1 years (IQR 23.2-43.3) at time of surgery. Median time from trauma to surgery was 9 days and mean follow-up time was 6.6 years. Median questionnaire scores were: Lysholm 79.5 (IQR 65.0-89.0), Tegner 4.0 (IQR 3.7-6.0), Meyers 3.0 (IQR 3.0-4.0), and mean IKDC was 63.8 (SD 18.9). Median flexion and extension of the injured knee was 124° (IQR 115-129.5) and 0° (IQR - 5 to 0), respectively. Median KT-1000 differential was 0.7 mm (IQR 0.1-3.1) for ACL and 0.9 mm (IQR 0.2-1.4) for PCL. Mean differential for Telos was 2.5 mm (SD 5.8) for ACL, 4 mm (IQR 2-6.3) for PCL 30°, and 8.2 mm (SD 4.4) for PCL 90° (consistent with PCL laxity). More than 90% of patients had good anterior articular stability and > 60% of patients had good posterior articular stability.

CONCLUSIONS

Acute repair and augmentation of knee dislocations with LARS synthetic ligaments resulted in satisfactory outcomes for the ACL and collateral structures. Telos stress radiography showed PCL laxity in more than half of cases despite low laxity results with KT-1000. The perception of patients about knee function was sustained in time.

LEVEL OF EVIDENCE

IV.

Femoral Trochleoplasty for Recurrent Patellar Dislocation: Treating the Underlying Trochlear Dysplasia

The patellofemoral joint presents a complex biomechanical interaction involving soft tissues and bony structures to maintain joint stability. The most relevant factor is trochlear dysplasia which is present in 85% of patients. Femoral trochleoplasty is a surgical procedure to recreate the trochlear groove. This case report describes a young patient who had all clinical factors of patellar instability and trochlear dysplasia. Radiology studies showed trochlear dysplasia type C according to the Dejour classification. The patient underwent a trochleoplasty with an elevated flap of cartilage and subchondral bone as described by Ryzek and Schöttle [J Knee Surg 2015; 28(4): 297–302], associated with the reconstruction of the medial patellofemoral ligament. Femoral trochleoplasty is a surgical procedure to recreate the trochlear groove by removing subchondral bone to create a new trochlear sulcus, while respecting the kinematics and biomechanics of the patellofemoral joint.

Incidence of symptomatic venous thromboembolism in 2372 knee and hip replacement patients after discharge: data from a thromboprophylaxis registry in Montreal, Canada

Background

Low-molecular-weight heparin (LMWH) is a recommended anticoagulant for thromboprophylaxis after major orthopedic surgery. Dabigatran etexilate is an oral anticoagulant recognized as noninferior to LMWH. We aimed to assess the incidence of symptomatic venous thromboembolic events (VTEs) after discharge in patients who underwent joint replacement, using a hospital registry.

Patients and methods

Patients who underwent total knee and hip arthroplasty between September 2011 and March 2015 were selected. Subcutaneous enoxaparin (30 mg twice daily) was given during hospitalization. At discharge, patients received either enoxaparin 30 mg twice daily/40 mg once daily or dabigatran 220 mg/150 mg once daily. Patients were seen or called at 2, 6, and 12 weeks after surgery. Outcomes were the number of VTEs, including deep venous thrombosis, pulmonary embolism, and the number of major/minor bleeding events after discharge.

Results

After discharge, 1468 patients were prescribed enoxaparin and 904 dabigatran (1396 total knee arthroplasty and 976 total hip arthroplasty patients). Mean age was 66±10 years, and 60% were female. The cumulative incidence of VTEs during the 12-week follow-up was 0.7%. One patient sustained a VTE during the switch window. Seven patients sustained a pulmonary embolism (0.3%). There was no statistical difference between the total knee arthroplasty and total hip arthroplasty groups. The incidence of major and minor bleeding events during follow-up was 0.3% and 30.3%, respectively. These events had a higher incidence in the dabigatran group compared to the enoxaparin group after discharge (p<0.05), but not between knee and hip replacement groups for major bleeding events.

Conclusion

A pharmaceutical prophylaxis protocol using LMWH and dabigatran during the post-discharge period resulted in low incidences of VTE and equivalence between treatments. However, the increased number of major and minor bleeding events in patients taking dabigatran is of concern regarding the safety and needs to be evaluated using analyses adjusted for risk factors.

Total knee arthroplasty with unexplained pain: new insights from kinematics

INTRODUCTION

Up to 20% of total knee arthroplasty patients remain unsatisfied post-surgery, and a large proportion of them report anterior knee pain. This study aims to verify whether patients who experience anterior knee pain after total knee arthroplasty (TKA) will exhibit kinematic characteristics similar to those associated with patellofemoral syndrome, including in the frontal and transverse planes.

MATERIALS AND METHODS

Using four different assessment methods [radiological, patient-reported outcome, musculoskeletal assessment with functional performance testing, and a 3D kinematic assessment during gait], the clinical and 3D knee kinematic profiles of three groups were compared: a painful and an asymptomatic TKA group and a healthy control group. All three groups underwent a three-dimensional kinematic knee assessment while walking on a treadmill. Prosthetic component rotation was assessed through a CT scan measurement performed by one experienced radiologist. Flexion/extension, ab/adduction, and tibial internal rotation curves were compared, and significant differences were highlighted through ANCOVA analysis performed on SPSS.

RESULTS

A total of 62 knees were evaluated, 24 asymptomatic, 21 painful, and 17 control. A dynamic flexion contracture during gait was observed in the painful group, which was associated with a lack of flexibility of the thigh muscles. Moreover, painful TKA cases exhibited a valgus alignment (- 1.5°) during stance, which increases the Q angle and lateralizes the patella. Finally, CT scan evaluation of painful total knee arthroplasty patients revealed that their combined components rotation was in slight internal rotation (- 1.4°, SD 7.0°).

CONCLUSIONS

Painful TKA patients presented three well-known characteristics that tend to increase patellofemoral forces and that could be the cause of the unexplained pain: a stiff knee gait, a valgus alignment when walking, and combined TKA components slightly internally rotated.

The impact of a standardized order set for the management of non-hip fragility fractures in a Fracture Liaison Service

We analysed the impact of a standardized order set empowering staff nurses to independently manage a Fracture Liaison Service over a 9-month period. Nurses identified between 30 and 70 % of non-hip fragility fractures to the unit in charge of management over time. The latter managed 58 % of referred patients.

INTRODUCTION

The main goal of this study was to evaluate the impact of a standardized order set empowering nurses to independently manage a fracture liaison service (FLS).

METHODS

Since November 2014, an order set allowed nurses of a Montreal hospital, Quebec, Canada to entirely manage an FLS on their own. Nurses followed an 6-h training program on-site. Emergency department (ED) and orthopaedic outpatient clinic (OC) nurses identified non-hip fragility fractures. Medical day treatment unit (MDTU) nurses were in charge of the management (investigation and treatment initiation). The list of patients, 50 years and older, with a fracture were retrieved for the period of November 2014 to July 2015. Performance was assessed with the rate of identification over time and the rate of management of non-hip fragility fractures.

RESULTS

Over the 9-month period, 346 patients of ≥50 years old were seen for a fracture, of which 190 met fragility criteria (excluding hip fractures). A sinusoid pattern of rates of identification between 30-70 % was observed over time. An average proportion of 58.1 % of fracture patients were managed by MDTU nurses.

CONCLUSIONS

A standardized order set legally allowing nurses to manage an FLS led to identification rates varying from 30-70 % and a management rate close to 60 % for referred patients over a 9-month period, which largely exceeds that of standard care. Identification was mostly compromised by difficulty integrating the order set into routine practice. Enforcement of the hospital policy on fragility fractures could help yield efficiency of identification of osteoporosis-related fractures by the staff.

The role of resolvin D1 in the regulation of inflammatory and catabolic mediators in osteoarthritis

OBJECTIVE AND DESIGN

Resolvin D1 (RvD1), an omega-3 fatty acid derivative, has shown remarkable properties in resolving inflammation, promoting tissue repair and preserving tissue integrity. In this study, we investigated RvD1 effects on major processes involved in osteoarthritis (OA) pathophysiology.

MATERIALS AND METHODS

Human OA chondrocytes were treated with either 1 ng/ml interleukin-1β (IL-1β) or 20 μM 4-hydroxynonenal (HNE), then treated or not with increased concentrations of RvD1 (0-10 μM). RvD1 levels were measured by enzyme immunoassay in synovial fluids from experimental dog model of OA and sham operated dogs obtained from our previous study. Cell viability was evaluated by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-SH-tetrazolium bromide assay. Parameters related to inflammation, catabolism and apoptosis were determined by enzyme-linked immunosorbent assay, Western blotting, and quantitative polymerase chain reaction. Glutathione (GSH) was assessed by commercial kit. The activation of mitogen-activated protein kinases and nuclear factor-kappaB (NF-κB) pathways was evaluated by Western blot.

RESULTS

We showed that RvD1 levels were higher in synovial fluids from OA joint compared to controls. In OA human chondrocytes, we demonstrated that RvD1 was not toxic up to 10 μM and stifled IL-1β-induced cyclooxygenase 2, prostaglandin E2, inducible nitric oxide synthase, nitric oxide, and matrix metalloproteinase-13. Our study of signalling pathways revealed that RvD1 suppressed IL-1β-induced activation of NF-κB/p65, p38/MAPK and JNK(1/2). Moreover, RvD1 prevented HNE-induced cell apoptosis and oxidative stress, as indicated by inactivation of caspases, inhibition of lactate dehydrogenase release, and increased levels of Bcl2 and AKT, as well as GSH.

CONCLUSION

This is the first in vitro study demonstrating the beneficial effect of RvD1 in OA. That RvD1 abolishing a number of factors known to be involved in OA pathogenesis renders it a clinically valuable agent in prevention of the disease.

Conditions of Use, Reliability, and Quality of Audio/Video-Mediated Communications During In-Home Rehabilitation Teletreatment for Postknee Arthroplasty

BACKGROUND

Audio/video-mediated communication between patients and clinicians using videoconferencing over telecommunication networks is a key component of providing teletreatments in rehabilitation.

OBJECTIVE

The objectives of this study were to (1) document the conditions of use, performance, and reliability of videoconferencing-based communication in the context of in-home teletreatment (TELE) following total knee arthroplasty (TKA) and (2) assess from the perspective of the providers, the quality attributes of the technology used and its impact on clinical objectives.

MATERIALS AND METHODS

Descriptive embedded study in a randomized controlled trial using a sample of 97 post-TKA patients, who received a total of 1,431 TELE sessions. Technical support use, service delivery reliability, performance, and use of network connection were assessed using self-report data from a costing grid and automated logs captured from videoconferencing systems. Physical therapists assessed the quality and impact of video-mediated communications after each TELE session on seven attributes.

RESULTS

Installation of a new Internet connection was required in 75% of the participants and average technician's time to install test and uninstall technology (including travel time) was 308.4 min. The reliability of service delivery was 96.5% of planned sessions with 21% of TELE session requiring a reconnection during the session. Remote technical support was solicited in 43% of the sessions (interventions were less than 3-min duration). Perceived technological impacts on video-mediated communications were minimal with quality of the overall technical environment evaluated as good or acceptable in 96% of the sessions and clinical objectives reached almost completely or completely in 99% of the sessions.

CONCLUSIONS

In-home rehabilitation teletreatments can be delivered reliably but requires access to technical support for the initial setup and maintenance. Optimization of the processes of reliably connecting patients to the Internet, getting the telerehabilitation platform in the patient's home, installing, configuring, and testing will be needed to generalize this approach of service delivery.

In-Home Telerehabilitation Compared with Face-to-Face Rehabilitation After Total Knee Arthroplasty: A Noninferiority Randomized Controlled Trial

BACKGROUND

The availability of less resource-intensive alternatives to home visits for rehabilitation following orthopaedic surgeries is important, given the increasing need for home care services and the shortage of health resources. The goal of this trial was to determine whether an in-home telerehabilitation program is not clinically inferior to a face-to-face home visit approach (standard care) after hospital discharge of patients following a total knee arthroplasty.

METHODS

Two hundred and five patients who had a total knee arthroplasty were randomized before hospital discharge to the telerehabilitation group or the face-to-face home visit group. Both groups received the same rehabilitation intervention for two months after hospital discharge. Patients were evaluated at baseline (before total knee arthroplasty), immediately after the rehabilitation intervention (two months after discharge), and two months later (four months after discharge). The primary outcome measure was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire at the last follow-up evaluation. Secondary outcome measures included the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire, functional and strength tests, and knee range of motion. The noninferiority margin was set at 9% for the WOMAC.

RESULTS

The demographic and clinical characteristics of the two groups of patients were similar at baseline. At the last follow-up evaluation, the mean differences between the groups with regard to the WOMAC gains, adjusted for baseline values, were near zero (for 182 patients in the per-protocol analysis): -1.6% (95% confidence interval [CI]: -5.6%, 2.3%) for the total score, -1.6% (95% CI: -5.9%, 2.8%) for pain, -0.7% (95% CI: -6.8%, 5.4%) for stiffness, and -1.8% (95% CI: -5.9%, 2.3%) for function. The confidence intervals were all within the predetermined zone of noninferiority. The secondary outcomes had similar results, as did the intention-to-treat analysis, which was conducted afterward for 198 patients.

CONCLUSIONS

Our results demonstrated the noninferiority of in-home telerehabilitation and support its use as an effective alternative to face-to-face service delivery after hospital discharge of patients following a total knee arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Reliability, validity, and responsiveness of the Western Ontario and McMaster Universities Osteoarthritis Index for elderly patients with a femoral neck fracture

BACKGROUND

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been extensively evaluated in groups of patients with osteoarthritis, yet not in patients with a femoral neck fracture. This study aimed to determine the reliability, construct validity, and responsiveness of the WOMAC compared with the Short Form-12 (SF-12) and the EuroQol 5D (EQ-5D) questionnaires for the assessment of elderly patients with a femoral neck fracture.

METHODS

Reliability was tested by assessing the Cronbach alpha. Construct validity was determined with the Pearson correlation coefficient. Change scores were calculated from ten weeks to twelve months of follow-up. Standardized response means and floor and ceiling effects were determined. Analyses were performed to compare the results for patients less than eighty years old with those for patients eighty years of age or older.

RESULTS

The mean WOMAC total score was 89 points before the fracture in the younger patients and increased from 70 points at ten weeks to 81 points at two years postoperatively. In the older age group, these scores were 86, 75, and 78 points. The mean WOMAC pain scores before the fracture and at ten weeks and two years postoperatively were 92, 76, and 87 points, respectively, in the younger age group and 92, 84, and 93 points in the older age group. Function scores were 89, 68, and 79 points for the younger age group and 84, 71, and 73 points for the older age group. The Cronbach alpha for pain, stiffness, function, and the total scale ranged from 0.83 to 0.98 for the younger age group and from 0.79 to 0.97 for the older age group. Construct validity was good, with 82% and 79% of predefined hypotheses confirmed in the younger and older age groups, respectively. Responsiveness was moderate. No floor effects were found. Moderate to large ceiling effects were found for pain and stiffness scales at ten weeks and twelve months in younger patients (18% to 36%) and in the older age group (38% to 53%).

CONCLUSIONS

The WOMAC showed good reliability, construct validity, and responsiveness in both age groups of elderly patients with a femoral neck fracture who had been physically and mentally fit before the fracture. The instrument is suitable for use in future clinical studies in these populations.

CLINICAL RELEVANCE

The results are based on two clinical trials. The questionnaires used concern pure, clinically relevant issues (ability to walk, climb stairs, etc.). Moreover, the results can be used for future research comparing clinical outcomes (or treatments) for populations with a femoral neck fracture.

Cost analysis of in-home telerehabilitation for post-knee arthroplasty

BACKGROUND

Rehabilitation provided through home visits is part of the continuum of care after discharge from hospital following total knee arthroplasty (TKA). As demands for rehabilitation at home are growing and becoming more difficult to meet, in-home telerehabilitation has been proposed as an alternate service delivery method. However, there is a need for robust data concerning both the effectiveness and the cost of dispensing in-home telerehabilitation.

OBJECTIVE

The objective of this study was to document, analyze, and compare real costs of two service delivery methods: in-home telerehabilitation and conventional home visits.

METHODS

The economic analysis was conducted as part of a multicenter randomized controlled trial (RCT) on telerehabilitation for TKA, and involved data from 197 patients, post-TKA. Twice a week for 8 weeks, participants received supervised physiotherapy via two delivery methods, depending on their study group allocation: in-home telerehabilitation (TELE) and home-visit rehabilitation (VISIT). Patients were recruited from eight hospitals in the province of Quebec, Canada. The TELE group intervention was delivered by videoconferencing over high-speed Internet. The VISIT group received the same intervention at home. Costs related to the delivery of the two services (TELE and VISIT) were calculated. Student's t tests were used to compare costs per treatment between the two groups. To take distance into account, the two treatment groups were compared within distance strata using two-way analyses of variance (ANOVAs).

RESULTS

The mean cost of a single session was Can $93.08 for the VISIT group (SD $35.70) and $80.99 for the TELE group (SD $26.60). When comparing both groups, real total cost analysis showed a cost differential in favor of the TELE group (TELE minus VISIT: -$263, 95% CI -$382 to -$143). However, when the patient's home was located less than 30 km round-trip from the health care center, the difference in costs between TELE and VISIT treatments was not significant (P=.25, .26, and .11 for the <10, 10-19, and 20-29 km strata, respectively). The cost of TELE treatments was lower than VISIT treatments when the distance was 30 km or more (30-49 km: $81<$103, P=.002; ≥50 km: $90<$152, P<.001).

CONCLUSIONS

To our knowledge, this is the first study of the actual costs of in-home telerehabilitation covering all subcosts of telerehabilitation and distance between the health care center and the patient's home. The cost for a single session of in-home telerehabilitation compared to conventional home-visit rehabilitation was lower or about the same, depending on the distance between the patient's home and health care center. Under the controlled conditions of an RCT, a favorable cost differential was observed when the patient was more than 30 km from the provider. Stakeholders and program planners can use these data to guide decisions regarding introducing telerehabilitation as a new service in their clinic.

TRIAL REGISTRATION

International Standard Registered Clinical Study Number (ISRCTN): 66285945; http://www.isrctn.com/ISRCTN66285945 (Archived by WebCite at http://www.webcitation.org/6WlT2nuX4).

Objective grading of the pivot shift phenomenon using a support vector machine approach

The pivot shift test is the only clinical test that has been shown to correlate with subjective criteria of knee joint function following rupture of the anterior cruciate ligament. The grade of the pivot shift is important in predicting short- and long-term outcome. However, because this grade is established by a clinician in a subjective manner, the pivot shift's value as a clinical tool is reduced. The purpose of this study was to develop a system that will objectively grade the pivot shift test based on recorded knee joint kinematics. Fifty-six subjects with different degrees of knee joint stability had the pivot shift test performed by one of eight different orthopaedic surgeons while their knee joint kinematics were recorded. A support vector machine based algorithm was used to objectively classify these recordings according to a clinical grade. The grades established by the surgeons were used as the gold standard for the development of the classifier. There was substantial agreement between our classifier and the surgeons in establishing the grade (weighted kappa=0.68). Seventy-one of 107 recordings (66%) were given the same grade and 96% of the time our classifier was within one grade of that given by the surgeons. Moreover, grades 0 and 1 were distinguished from grade 2 to 3 with 86% sensitivity and 90% specificity. Our results show the feasibility of automatically grading the pivot shift in a manner similar to that of an experienced clinician, based on knee joint kinematics.

Accounting for velocity of the pivot shift test manoeuvre decreases kinematic variability

The pivot shift test is the only clinical test which correlates with knee function following rupture of the ACL. A grade is given to the pivot shift in a subjective manner, leading to efforts to quantify the bone movements and correlate them to the grade. However, the dynamic and unconstrained nature of the manoeuvre introduces important kinematic variability. Our main objective was to develop a method to lessen the variability attributable to clinician technique, therefore increasing inter-grade differences. Three different orthopaedic surgeons each performed the pivot shift test on 12 subjects. Knee joint kinematics were recorded using electromagnetic motion capture devices. Inter-clinician variability was quantified and a method was developed to diminish it, using the angular velocity of flexion. This method was then applied to a larger population composed of 127 knees with various degrees of instability, evaluated by one of eight different orthopaedic surgeons. The clinical grades given by the clinicians were in almost perfect agreement (kappa=0.83). Normalization of kinematic parameters using the angular velocity of knee joint flexion produced by the clinicians reduced the intra-clinician variability by 20%, resulting in an intra-class correlation coefficient (ICC) of 0.52, up from 0.41 before normalization. This allowed for more significant differences between the grades of pivot shift. Simple normalisation of pivot shift kinematics using the angular velocity of flexion reduces clinician-related variability and allows for significant differences between the different grades. These results are an important step towards developing an objective measurement tool for the pivot shift phenomenon.

Gait adaptation in chronic anterior cruciate ligament-deficient patients: Pivot-shift avoidance gait

BACKGROUND

A variety of biomechanical adaptations of the knee during gait have been reported in ACL-deficient patients to cope with anteroposterior knee instability. However, strategies to prevent rotatory knee instability are less recognized. We hypothesized that ACL-deficient patients would make distinctive gait changes to prevent anterolateral rotatory knee instability. Specifically, we hypothesized that during the terminal stance phase of the gait cycle, ACL-deficient patients would reduce the internal rotation knee joint moment and exhibit a higher knee flexion angle. We call this altered gait a pivot-shift avoidance gait. We also hypothesized that patients would not be able to adapt their knee biomechanics as efficiently at a fast gait speed.

METHODS

Twenty-nine patients with chronic ACL deficiency and 15 healthy volunteers took part in a treadmill gait analysis. The terminal stance phase was analyzed under both comfortable and fast gait speed conditions.

FINDINGS

At both gait speeds, ACL-deficient patients significantly reduced the internal rotation knee joint moment and showed larger knee flexion angles during the terminal stance phase of the gait cycle than did the control group. However, the difference in the minimum knee flexion angle between groups under the fast gait speed condition was not statistically significant.

INTERPRETATION

ACL-deficient patients adopted the proposed pivot-shift avoidance gait, possibly to prevent anterolateral rotatory knee instability. The patients were not able to adapt their knee biomechanics as effectively during fast-paced walking. This study reinforces the pertinence of gait analysis in ACL-deficient knees to acquire more information about the function of the knee joint.

Evaluation of reconstructive surgery using artificial ligaments in 71 acute knee dislocations

This retrospective study assessed the results of 71 patients with knee dislocations who underwent acute combined repair and reconstruction using Ligament Advancement Reinforcement System (LARS) artificial ligaments between June 1996 and May 2008 with a follow-up between two and eight years. The outcome measures used were the Lysholm score, the International Knee Documentation Committee form (IKDC 2000), the Tegner activity level score, the Meyers ratings, Telos stress radiography, range of motion and clinical knee stability testing. When comparing high- versus low-energy dislocations and knee dislocation (KD) II/III versus KD IV injuries, a better Lysholm score for the knee dislocation (KD) II/III group was found compared with the KD IV group. The subjective and objective findings from our study are satisfactory and comparable with the results of other studies of knee dislocations. Our findings suggest that with a mean follow-up of 54 months, acute combined repair and reconstruction with LARS ligaments is a valid alternative for treating knee dislocations.

Feature selection using a principal component analysis of the kinematics of the pivot shift phenomenon

The pivot shift test reproduces a complex instability of the knee joint following rupture of the anterior cruciate ligament. The grade of the pivot shift test has been shown to correlate to subjective criteria of knee joint function, return to physical activity and long-term outcome. This severity is represented by a grade that is attributed by a clinician in a subjective manner, rendering the pivot shift test poorly reliable. The purpose of this study was to unveil the kinematic parameters that are evaluated by clinicians when they establish a pivot shift grade. To do so, eight orthopaedic surgeons performed a total of 127 pivot shift examinations on 70 subjects presenting various degrees of knee joint instability. The knee joint kinematics were recorded using electromagnetic sensors and principal component analysis was used to determine which features explain most of the variability between recordings. Four principal components were found to account for most of this variability (69%), with only the first showing a correlation to the pivot shift grade (r = 0.55). Acceleration and velocity of tibial translation were found to be the features that best correlate to the first principal component, meaning they are the most useful for distinguishing different recordings. The magnitudes of the tibial translation and rotation were amongst those that accounted for the least variability. These results indicate that future efforts to quantify the pivot shift should focus more on the velocity and acceleration of tibial translation and less on the traditionally accepted parameters that are the magnitudes of posterior translation and external tibial rotation.

4-Hydroxynonenal induces apoptosis in human osteoarthritic chondrocytes: the protective role of glutathione-S-transferase

Introduction

4-Hydroxynonenal (HNE) is one of the most abundant and reactive aldehydes of lipid peroxidation products and exerts various effects on intracellular and extracellular signalling cascades. We have previously shown that HNE at low concentrations could be considered as an important mediator of catabolic and inflammatory processes in osteoarthritis (OA). In the present study, we focused on characterizing the signalling cascade induced by high HNE concentration involved in cell death in human OA chondrocytes.

Methods

Markers of apoptosis were quantified with commercial kits. Protein levels were evaluated by Western blotting. Glutathione (GSH) and ATP levels were measured with commercial kits. Glucose uptake was assessed by 2-deoxy-D-[³H]-glucose. The role of GSH-S-transferase A4-4 (GSTA4-4) in controlling HNE-induced chondrocyte apoptosis was investigated by chondrocyte transfection with small interfering RNA (siRNA) or with the expression vector of GSTA4-4.

Results

Our data showed that HNE at concentrations of up to 10 μM did not alter cell viability but was cytotoxic at concentrations of greater than or equal to 20 μM. HNE-induced chondrocyte death exhibited several classical hallmarks of apoptosis, including caspase activation, cytochrome c and apoptosis-induced factor release from mitochondria, poly (ADP-ribose) polymerase cleavage, Bcl-2 downregulation, Bax upregulation, and DNA fragmentation. Our study of signalling pathways revealed that HNE suppressed pro-survival Akt kinase activity but, in contrast, induced Fas/CD95 and p53 expression in chondrocytes. All of these effects were inhibited by an antioxidant, N-acetyl-cysteine. Analysis of cellular energy and redox status showed that HNE induced ATP, NADPH, and GSH depletion and inhibited glucose uptake and citric acid cycle activity. GSTA4-4 ablation by the siRNA method augmented HNE cytotoxicity, but, conversely, its overexpression efficiently protected chondrocytes from HNE-induced cell death.

Conclusion

Our study provides novel insights into the potential mechanisms of cell death in OA cartilage and suggests the potential role of HNE in OA pathophysiology. GSTA4-4 expression is critically important for cellular defence against oxidative stress-induced cell death in OA cartilage, possibly by HNE elimination.

[Open-wedge retro-tubercular tibial osteotomy: an innovating technique]

Open-wedge tibial osteotomy for varus correction is a common orthopedic procedure. The rate of complications remains significant: loss of correction, nonunion, patellar infera... We propose a new open-wedge technique for tibial osteotomy which has several advantages: less risk of patella infera, improved bone healing, excellent mechanical stability. The osteotomy involves two cuts with an anterior portion ending distally to the tibial tubercle. This preserves the integrity of the patellar tendon and maintains contact between the proximal tibia and the tibial tubercle. Adjunction of an anteroposterior screw adds stability. The anterior plane of the osteotomy provides an excellent surface contact favoring bone healing. The posterior plane is the same as with a "classical" open-wedge osteotomy. The lateral cortical must always remain intact (hinge). The technique described here does not require any specific instrumentation and is compatible with most of the available osteosynthesis implants.

Evidence for two distinct pathways in TNFalpha-induced membrane and soluble forms of ICAM-1 in human osteoblast-like cells isolated from osteoarthritic patients

OBJECTIVE

The present study aimed to investigate the modulation of membrane-bound intercellular adhesion molecule-1 (mICAM-1) and soluble ICAM-1 (sICAM-1) expression by tumor necrosis factor-alpha (TNFalpha) in human osteoarthritic (OA) osteoblasts.

METHODS

Cultured human primary osteoblasts were stimulated with increasing concentrations of human recombinant TNFalpha. Expression of mICAM-1 and sICAM-1 was evaluated by immunocytochemistry, enzyme-linked immunosorbent assay and semi-quantitative reverse transcriptase-polymerase chain reaction. In addition, we investigated the molecular mechanisms underlying ICAM-1 induction by TNFalpha, focusing on the activation of the mitogen-activated protein kinases (MAPKs) and nuclear factor-kappaB (NF-kappaB) pathways.

RESULTS

Our data showed that TNFalpha dose-dependently increased mICAM-1 and sICAM-1 expression at the protein and mRNA levels in OA osteoblasts. The inhibitor of de novo mRNA synthesis, actinomycin D, suppressed TNFalpha-induced mICAM-1 and sICAM-1 expression. Upon examination of the signaling components, we found that TNFalpha was a potent activator of p38, p44/42, p54/46 MAPK, and IkappaBalpha (IkappaBalpha). The chemical inhibitors of p38, p44/42 MAPK, and NF-kappaB blocked TNFalpha-induced mICAM-1 expression but not that of sICAM-1. Transfection experiments revealed that p38 MAPK or IkappaB kinase alpha (IKKalpha) overexpression enhanced TNFalpha-induced mICAM-1 production. Furthermore, osteoblasts treatment with a chemical inhibitor of metalloproteinase-9 (MMP-9) activity, a proteolytic enzyme involved in ICAM-1 cleavage, evoked a significant 25% decrease of TNFalpha-induced sICAM-1 release.

CONCLUSION

Taken together, these findings illustrate the central role played by TNFalpha in the regulation of ICAM-1. We suggest that TNFalpha differentially regulates sICAM-1 and mICAM-1 expression and that sICAM-1 release involves, in part, the proteolytic cleavage of mICAM-1 by MMP-9. The capacity of the MMP-9 inhibitor to prevent sICAM-1 production may be useful for the development of novel therapeutic approaches relevant to OA.

Production of lipid peroxidation products in osteoarthritic tissues: new evidence linking 4-hydroxynonenal to cartilage degradation

OBJECTIVE

The lipid peroxidation product 4-hydroxynonenal (HNE) is prominently produced in osteoarthritic (OA) synovial cells, but its specific contribution to cartilage destruction is not understood. This study was designed to test whether HNE signaling and binding are involved in OA cartilage degradation through type II collagen (CII) and matrix metalloproteinase 13 (MMP-13) modulation.

METHODS

HNE levels in synovial fluid and in isolated OA chondrocytes treated with free radical donors were determined by enzyme-linked immunosorbent assay. The formation of the HNE/CII adducts was measured in cartilage explants by immunoprecipitation. Levels of CII and MMP-13 messenger RNA and protein were determined by reverse transcription-polymerase chain reaction, Western blotting, and by the use of commercial kits.

RESULTS

Levels of HNE/protein adducts were higher in OA synovial fluid compared with normal synovial fluid and were higher in OA chondrocytes treated with free radical donors compared with untreated cells. In cartilage explants, HNE induced CII cleavage, as established by the generation of neoepitopes. The level of HNE/CII adducts was increased in OA cartilage explants incubated with free radical donors. Modification of CII by HNE accelerated its degradation by active MMP-13. In isolated OA chondrocytes, HNE inhibited the expression of CII and tissue inhibitor of metalloproteinases 1 and induced MMP-13 mainly through activation of p38 MAPK. In vitro, HNE binding to MMP-13 activated this enzyme at a molar ratio of 1:100 (MMP-13 to HNE).

CONCLUSION

The increased level of HNE in OA cartilage and the ability of HNE to induce transcriptional and posttranslational modifications of CII and MMP-13 suggest that this aldehyde could play a role in OA.

Expression and regulation of microsomal prostaglandin E synthase-1 in human osteoarthritic cartilage and chondrocytes

OBJECTIVE

Elevated production of prostaglandin E2 (PGE2) plays an important role in the pathogenesis of arthritis. Recently, an inducible microsomal prostaglandin E synthase-1 (mPGES-1) was identified. This enzyme is functionally coupled with cyclooxygenase-2 (COX-2) and converts the COX product PGH2 to PGE2. We analyzed expression of mPGES-1 in human normal and osteoarthritic (OA) cartilage and determined the effect of different inflammatory agonists on the expression of mPGES-1 in OA chondrocytes.

METHODS

Expression of mPGES-1 mRNA and protein in cartilage was determined by quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry, respectively. OA chondrocytes were treated with different inflammatory agents, and mPGES-1 protein expression was evaluated by Western blot. Activation of the mPGES-1 promoter was assessed in transient transfection experiments.

RESULTS

Levels of mPGES-1 mRNA and protein were markedly elevated in OA versus normal cartilage. Treatment of chondrocytes with interleukin 1beta (IL-1beta) induced expression of mPGES-1 protein in a dose- and time-dependent manner. This appears to occur at the transcriptional level, as IL-1beta induced expression of mPGES-1 mRNA and the activity of this gene promoter. Tumor necrosis factor-alpha (TNF-alpha) and IL-17 also upregulated expression of mPGES-1 protein and displayed a synergistic effect with IL-1beta. Peroxisome proliferator-activated receptor-gamma ligands, 15-deoxy-delta(12,14)-prostaglandin J2 and troglitazone, inhibited IL-1beta-induced mPGES-1 protein expression, an effect that was reversed by exogenous PGE2.

CONCLUSION

Our study shows that mPGES-1 expression is upregulated in OA versus normal cartilage and that proinflammatory cytokines increased mPGES-1 expression in chondrocytes. These data suggest that mPGES-1 may prove to be an interesting therapeutic target for controlling PGE2 synthesis.

Leukotriene and prostaglandin synthesis pathways in osteoarthritic synovial membranes: regulating factors for interleukin 1beta synthesis

OBJECTIVE

To study the mechanisms responsible for the cross-talk between lipoxygenase (LOX) and cyclooxygenase (COX) pathways in human osteoarthritic (OA) synovial explants, and to confirm the arachidonic acid (AA) shunting phenomenon and its influence on interleukin 1beta (IL-1beta) synthesis.

METHODS

Synovial membrane explants were cultured in the absence or presence of different drugs that inhibit COX and/or LOX activities. Concentrations of prostaglandin E2 (PGE2), leukotriene B4 (LTB4), lipoxin A4 (LXA4), and IL-1beta were measured.

RESULTS

When membrane explants were incubated with naproxen (COX inhibitor) under unstimulated conditions, the production of LTB4 was dose-dependently enhanced, reaching a 5-fold increase over the control. This shunt could be partially reversed by the addition of exogenous PGE2. Under lipopolysaccharide (LPS) stimulation, both licofelone (COX/LOX inhibitor) at therapeutic concentrations and NDGA (LOX inhibitor) inhibited LTB4 production, whereas naproxen did not amplify the LPS-induced LTB4 production. Conversely, using NDGA, it was found that a shunt of AA from the LOX to the COX pathway did not occur. Under LPS conditions, both naproxen and licofelone inhibited LXA4, inducing an increase in the LTB4/LXA4 ratio with naproxen treatment but not with licofelone. Under these conditions, naproxen treatment induced a higher level of IL-1beta production.

CONCLUSION

We demonstrated in OA synovium that a shunt from AA to the LOX pathway occurred and that treatment with a nonselective COX inhibitor could increase the production of LTB4 and secondarily the synthesis of IL-1beta. Therefore treatment with licofelone, which can act on both COX and LOX pathways, may have some interesting properties in the treatment of OA.

Inhibition of interleukin-1?-induced cyclooxygenase 2 expression in human synovial fibroblasts by 15-deoxy-?12,14-prostaglandin J2 through a histone deacetylase-independent mechanism

OBJECTIVE

The cyclooxygenase (COX) metabolite, 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), has been reported to inhibit the expression of a number of genes involved in the pathogenesis of arthritis. However, its effects on COX-2 remain controversial. We undertook this study to investigate the effects of 15d-PGJ(2) on interleukin-1beta (IL-1beta)-induced COX-2 expression in human synovial fibroblasts (HSFs).

METHODS

HSFs were cultured with IL-1beta in the absence or presence of 15d-PGJ(2), and the levels of COX-2 protein and messenger RNA (mRNA) expression were evaluated using Western blotting and real-time reverse transcriptase-polymerase chain reaction, respectively. COX-2 promoter activity was analyzed in transient transfection experiments. Chromatin immunoprecipitation assays were performed to evaluate the level of histone acetylation and the recruitment of histone deacetylases (HDACs) 1, 2, and 3 and histone acetylase (HAT) p300 to the COX-2 promoter.

RESULTS

IL-1beta-induced COX-2 protein and mRNA expression, as well as COX-2 promoter activation, were inhibited by 15d-PGJ(2). Troglitazone, a selective peroxisome proliferator-activated receptor gamma (PPARgamma) ligand, enhanced COX-2 expression, while GW9662, a specific PPARgamma antagonist, relieved the suppressive effect of 15d-PGJ(2). IL-1beta-induced histone H3 acetylation was selectively blocked by 15d-PGJ(2). The reduction of histone H3 acetylation did not correlate with the recruitment of HDACs to the COX-2 promoter. Also, treatment with the specific HDAC inhibitor, trichostatin A, did not relieve the suppressive effect of 15d-PGJ(2), indicating that HDACs are not involved in the inhibitory effect of 15d-PGJ(2). Furthermore, 15d-PGJ(2) blocked IL-1beta-induced recruitment of p300 to the COX-2 promoter, which may be the mechanism for decreased histone H3 acetylation and COX-2 expression. In accordance with this, overexpression of p300, but not of a mutant p300 lacking HAT activity, relieved the inhibitory effect of 15d-PGJ(2) on COX-2 promoter activation.

CONCLUSION

These data suggest that 15d-PGJ(2) can inhibit IL-1beta-induced COX-2 expression by an HDAC-independent mechanism, probably by interfering with HAT p300.

Knee dislocations: experience at the Hôpital du Sacré-Coeur de Montréal

INTRODUCTION

Although many options exist for ligament reconstruction in knee dislocations, the optimal treatment remains controversial. Allografts and autografts have both been used to reconstruct the cruciate ligaments. We present the results of reconstruction using artificial ligaments at Hôpital du Sacré-Coeur in Montréal.

METHODS

We reviewed the treatment of all patients with knee dislocations seen between June 1996 and October 1999. The Lysholm score, ACL-quality of life (QoL) questionnaire, physical examination and Telos instrumented laxity measurement were used to evaluate the results.

RESULTS

Twenty patients (21 knees) participated in the study. The mean (and standard deviation [SD]) Lysholm score was 71.7 (18). Results from the ACL-QoL questionnaire showed a global impairment in QoL. Mean (and SD) range of motion and flexion were 118 degrees (10.9 degrees) and 2 degrees (2.9 degrees) respectively. Mean (and SD) radiologic laxity evaluated with Telos for the anterior and posterior cruciate ligaments were 6.1 (5.7) mm and 7.3 (4.5) mm respectively.

CONCLUSIONS

Knee reconstruction with artificial ligaments shows promise, but further studies are necessary before it can be recommended for widespread use. This is the first study to show specifically a severe impairment in QoL in this patient population.

Differential gene expression and regulation of the bone morphogenetic protein antagonists follistatin and gremlin in normal and osteoarthritic human chondrocytes and synovial fibroblasts

OBJECTIVE

To compare gene expression in normal and osteoarthritic (OA) human chondrocytes using microarray technology. Of the novel genes identified, we selected follistatin, a bone morphogenetic protein (BMP) antagonist, and investigated its expression/regulation as well as that of 3 other antagonists, gremlin, chordin, and noggin, in normal and OA chondrocytes and synovial fibroblasts.

METHODS

Basal and induced gene expression were determined using real-time polymerase chain reaction. Gene regulation was monitored following treatment with inflammatory, antiinflammatory, growth, and developmental factors. Follistatin protein production was measured using a specific enzyme-linked immunosorbent assay, and localization of follistatin and gremlin in cartilage was determined by immunohistochemical analysis.

RESULTS

All BMP antagonists except noggin were expressed in chondrocytes and synovial fibroblasts. Follistatin and gremlin were significantly up-regulated in OA chondrocytes but not in OA synovial fibroblasts. Chordin was weakly expressed in normal and OA cells. Production of follistatin protein paralleled the gene expression pattern. Follistatin and gremlin were expressed preferentially by the chondrocytes at the superficial layers of cartilage. Tumor necrosis factor alpha and interferon-gamma significantly stimulated follistatin expression but down-regulated expression of gremlin. Interleukin-1beta (IL-1beta) had no effect on follistatin but reduced gremlin expression. Conversely, BMP-2 and BMP-4 significantly stimulated expression of gremlin but down-regulated that of follistatin. IL-13, dexamethasone, transforming growth factor beta1, basic fibroblast growth factor, platelet-derived growth factor type BB, and endothelial cell growth factor down-regulated the expression of both antagonists.

CONCLUSION

This study is the first to show the possible involvement of follistatin and gremlin in OA pathophysiology. The increased activin/BMP-binding activities of these antagonists could affect tissue remodeling. The data suggest that follistatin and gremlin might appear at different stages during the OA process, making them interesting targets for the treatment of this disease.

Identification and differential expression of human collagenase-3 mRNA species derived from internal deletion, alternative splicing, and different polyadenylation and transcription initiation sites

OBJECTIVE

Collagenase-3 is a metalloprotease that plays a role in tissue remodeling and pathological processes including arthritis. The human gene is transcribed into major (3.0 and 2.5 kb) and minor (2.2/2.0 kb) transcripts, as seen in Northern blot assays. We investigated the possibility that other transcripts, not detectable by Northern blot, were synthesized as either coding or regulatory RNAs that would modulate collagenase-3 expression and function/activity.

DESIGN

We screened a cDNA library and total RNA from human chondrocytes by plaque hybridization and RT-PCR, and expressed the transcripts in a cellular environment. The levels of expression of each transcript in normal and osteoarthritic joint cells and cartilage were monitored by RT-PCR.

RESULTS

We identified five different collagenase-3 RNA species derived from alternative polyadenylation sites (COL3-APS), internal deletion (COL3-DEL), alternative splicing (COL3-9B/COL3-9B-2), and different transcription initiation site (COL3-ATS and COL3-ATS-INT). Each transcript could be translated in a cellular environment. Interestingly, the proteins translated from the COL3-DEL and COL3-9B-2 transcripts had a modified hemopexin-like domain, suggesting altered collagenolytic activities. The transcript types COL3-APS, COL3-9B-2, and COL3-ATS were up-regulated in the osteoarthritic samples and expressed in the chondrosarcoma cell line SW1353.

CONCLUSION

Our data show that the human collagenase-3 gene is subjected to different levels of regulation and constitutes a more complex system than was originally thought.

Human adult chondrocytes express hepatocyte growth factor (HGF) isoforms but not HgF: potential implication of osteoblasts on the presence of HGF in cartilage

HGF is increased in human OA cartilage, possibly from Ob's. RT-PCR shows HGF isoforms are differently regulated between chondrocytes and Ob. A paracrine cross-talk between subchondral bone and cartilage may occur during OA. Recently, hepatocyte growth factor (HGF) has been identified by immunohistochemistry in cartilage and more particularly in the deep zone of human osteoarthritic (OA) cartilage. By investigating HGF expression in cartilage, we found that chondrocytes did not express HGF; however, they expressed the two truncated isoforms, namely HGF/NK1 and HGF/NK2. Because the only other cells localized near the deep zone are osteoblasts from the subchondral bone plate, we hypothesized that they were expressing HGF. Indeed, we found that HGF was synthesized by osteoblasts from the subchondral bone plate. Moreover, OA osteoblasts produced five times more HGF than normal osteoblasts and almost no HGF/NK1, unlike normal osteoblasts. Because prostaglandin E2 (PGE2) and pro-inflammatory cytokines such as interleukin (IL)-1 and IL-6 are involved in OA progression, we investigated whether these factors impact HGF produced by normal osteoblasts. PGE2 was the only factor tested that was able to stimulate HGF synthesis. However, the addition of NS398, a selective inhibitor of cyclo-oxygenase-2 (COX-2) had no effect on HGF produced by OA osteoblasts. HGF/NK2 had a moderate stimulating effect on HGF production by normal osteoblasts, whereas osteocalcin was not modulated by either HGF or HGF/NK2. When investigating signaling routes that might be implicated in OA osteoblast-produced HGF, we found that protein kinase A was at least partially involved. In summary, this study raises the hypothesis that the HGF found in articular cartilage is produced by osteoblasts, diffuses into the cartilage, and may be implicated in the OA process.

Interleukin 17 (IL-17) induces collagenase-3 production in human osteoarthritic chondrocytes via AP-1 dependent activation: differential activation of AP-1 members by IL-17 and IL-1beta

OBJECTIVE

In osteoarthritic (OA) synovial fluid, many proinflammatory cytokines coexist and stimulate chondrocytes. As interleukin 17 (IL-17) is a catabolic cytokine, we explored its effects on collagenase-3 production. In a comparative manner we identified IL-17 and IL-1beta induced transcription factors mediating upregulation of this enzyme's production.

METHODS

Collagenase-3 levels were determined by ELISA. Transfection experiments of human OA chondrocytes were performed, with the plasmids -1599CAT and -133CAT consisting of 1.6 kb and the first proximal 133 bp containing polyomavirus enhancer A-3 (PEA-3), activating protein-1 (AP-1), and TATA box of the human collagenase-3 promoter, respectively. Electrophoretic mobility shift assays were done with the AP-1 and PEA-3 oligonucleotides derived from the human collagenase-3 promoter sequence. Supershift assays were carried out with the specific antibodies against the Jun and Fos proteins.

RESULTS

IL-17 induced collagenase-3 expression and synthesis, with an EC50 at 10 ng/ml. Transfection experiments with wild-type -1599CAT and -133CAT and their mutated AP-1 or PEA-3 derivatives revealed that the AP-1 site was essential for basal and proinflammatory cytokine induced collagenase-3 promoter activity, whereas the PEA-3 motif exerted a cooperative effect. Of note, in OA chondrocytes, IL-17 and IL-1beta induced collagenase-3 production through AP-1 occurred with differential protein complexes: IL-17 stimulation resulted in FosB activation, while IL-1beta stimulated c-Fos. Data showed a strong activation of JunB only in cells showing a higher collagenase-3 basal level and low cytokine (IL-17 and IL-1beta) inducibility, suggesting this transcription factor protein acts as a negative regulator.

CONCLUSION

We demonstrated that IL-17 and IL-1beta induced collagenase-3 production in OA chondrocytes mainly through AP-1 mediated transcriptional activity but with differential protein complexes, suggesting that some AP-1 proteins play a pivotal role in the different cytokine responses in terms of collagenase-3 production. Our data might suggest that JunB protein plays a rate-limiting step in cytokine induced collagenase-3 production in OA chondrocytes.

Peroxisome proliferator--activated receptor gamma activators inhibit interleukin-1beta-induced nitric oxide and matrix metalloproteinase 13 production in human chondrocytes

OBJECTIVE

To determine the effects of peroxisome proliferator-activated receptor gamma (PPARgamma) agonists on interleukin-1 (IL-1) induction of nitric oxide (NO) and matrix metalloproteinase 13 (MMP-13) in human chondrocytes.

METHODS

PPARgamma expression and synthesis in human chondrocytes were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. Chondrocytes were cultured with IL-1beta, tumor necrosis factor alpha (TNFalpha), and IL-17 in the presence or absence of PPARgamma agonists, and NO and MMP-13 synthesis and expression levels were measured. Transient transfection experiments were performed with the 7-kb inducible NO synthase (iNOS) and 1.6-kb MMP-13 human promoters, as well as with the PPARgamma expression vector and the activator protein 1 (AP-1) and nuclear factor kappaB (NF-kappaB) reporter constructs.

RESULTS

RT-PCR and immunohistochemical analysis revealed that human chondrocytes expressed and produced PPARgamma. Treatment of chondrocytes with PPARgamma ligands BRL 49653 and 15-deoxy-delta12,14-prostaglandin J2 (15d-PGJ2), but not with PPARalpha ligand Wy 14643, decreased IL-1beta-induced NO and MMP-13 production in a dose-dependent manner. In addition, both iNOS and MMP-13 messenger RNA were inhibited in the presence of 15d-PGJ2. The inhibitory effect of PPARgamma activation was not restricted to IL-1beta, since TNFalpha- and IL-17-induced NO and MMP-13 production were also inhibited by 15d-PGJ2. In transient transfection experiments, we showed that a constitutively active form of mitogen-activated protein kinase kinase kinase 1 (AMEKK-1) induced the MMP-13 and iNOS human promoter activity. This process was reduced by 15d-PGJ2 and further inhibited by cotransfection with a PPARgamma expression vector. Similarly, in a PPARgamma-dependent manner, 15d-PGJ2 inhibited deltaMEKK-1-induced AP-1- and NF-kappaB-luciferase reporter plasmid activation.

CONCLUSION

The findings of this study demonstrate that PPARgamma agonists inhibit IL-1beta induction of both NO and MMP-13 in human chondrocytes. The inhibition occurs at least at the transcriptional level through a PPARgamma-dependent pathway, probably by interfering with the activation of AP-1 and NF-kappaB.

Hepatocyte growth factor induction of collagenase 3 production in human osteoarthritic cartilage: involvement of the stress-activated protein kinase/c-Jun N-terminal kinase pathway and a sensitive p38 mitogen-activated protein kinase inhibitor cascade

OBJECTIVE

Osteoarthritis (OA) involves both a decreased reparative process and an increased degradative phenomenon. Several cytokines and growth factors are known to facilitate the repair of articular cartilage defects. The hepatocyte growth factor (HGF) present in OA cartilage is suggested to be involved in the cartilage repair process as well as in matrix remodeling and chondrocyte migration, leading to partial reconstruction of articular cartilage. Since cell migration is often correlated with metalloprotease activity, the effect of HGF on collagenase 3 production was studied because of its possible implication in OA cartilage remodeling.

METHODS

We examined HGF-stimulated collagenase 3 production in human OA chondrocytes by Western and Northern blotting. Furthermore, we explored the intracellular signaling pathways through which HGF induced collagenase 3 production.

RESULTS

This study showed that HGF stimulated collagenase 3 production in human OA chondrocytes at the transcriptional level, and this induction was mediated by activation of the stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK) pathway, but not the p38 mitogen-activated protein kinase (MAPK). The p44/42 MAPKs were also phosphorylated and the use of their specific inhibitor (PD 98059) did not affect HGF-induced collagenase 3 production in OA chondrocytes. Induced collagenase 3 production via the SAPK/JNK pathway was mediated, at least in part, by the TRE site in the promoter, and in the activator protein 1 complex, c-Jun, JunD, and Fra-1 were activated. Surprisingly, further experiments revealed that the specific p38 MAPK inhibitor SB 202190 also inhibited collagenase 3 production early in the HGF-induced process. The 50% inhibitory concentration was as low as 50 nM, which is unlikely to be related to p38 MAPK inhibition (which is usually in the microM range), suggesting the involvement of another kinase sensitive to SB 202190.

CONCLUSION

This is the first study to show that HGF has the ability to induce both the expression and synthesis of collagenase 3 in OA chondrocytes. The effect is mediated by kinase cascades involving SAPK/JNK and another, unidentified kinase. This study provides novel information implicating a role for HGF in the pathophysiology of OA through its effect on the production of collagenase 3, which is an enzyme that is possibly involved in OA cartilage remodeling.

Osteoblast-like cells from human subchondral osteoarthritic bone demonstrate an altered phenotype in vitro: possible role in subchondral bone sclerosis

OBJECTIVE

Osteoarthritis (OA) is accompanied by subchondral bone sclerosis. The present study was undertaken to determine whether osteoblast-like cells in patients with OA show an abnormal phenotype that could contribute to this sclerosis.

METHODS

Explants and primary in vitro osteoblast-like cell cultures were prepared from subchondral bone specimens from OA patients or from bone removed at autopsy from individuals showing no signs of OA or metabolic bone disease. We measured the abundance and activity of urokinase plasminogen activator (uPA), and the levels of PA inhibitor (PAI-1) and insulin-like growth factor 1 (IGF-1) in conditioned media from both explants and osteoblast-like cells. The expression of osteoblast phenotypic biomarkers was also evaluated.

RESULTS

OA explants showed increased levels and activity of uPA, no changes in PAI-1 abundance, and increases in IGF-1 release, as compared with preparations from normal individuals. In vitro primary osteoblast-like cells showed results similar to the ex vivo findings for uPA, PAI-1, and IGF-1. Primary OA osteoblast-like cells also expressed higher alkaline phosphatase activity and osteocalcin release than normal cells, both under basal conditions and with 1,25(OH)2D3 (1,25-dihydroxyvitamin D) stimulation. Conversely, OA osteoblast-like cells showed blunted cAMP synthesis in response to human parathyroid hormone and prostaglandin E2 in contrast to the finding with normal osteoblast-like cells, a result that could not be attributed to altered adenylate cyclase activity.

CONCLUSION

Ex vivo and in vitro results indicate similar altered activities of OA osteoblasts as compared with normal cells. This suggests that an altered phenotype of subchondral osteoblasts may be a contributing factor in human OA.

Effect of IL-13 on cytokines, cytokine receptors and inhibitors on human osteoarthritis synovium and synovial fibroblasts

OBJECTIVE

In this study we investigated the effect of interleukin-13 (IL-13), an anti-inflammatory cytokine, for potential therapeutic use in osteoarthritis (OA).

DESIGN

We examined the effect of IL-13 on the synthesis and expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), IL-1 receptor antagonist (IL-1Ra) and stromelysin-1 on human OA synovial membrane in ex vivo cultures. In addition, we explored the effect of IL-13 on both the IL-1 receptor (IL-1R) and TNF-receptor (TNF-R) systems on OA synovial fibroblasts. This included determination of the levels of IL-1 beta and TNF-alpha receptor binding, IL-1Ra and TNF-soluble receptors 55 and 75 (TNF-sR55 and TNF-sR75).

RESULTS

In OA synovial membrane treated with LPS, IL-13 inhibited the synthesis of IL-1 beta, TNF-alpha and stromelysin-1, but increased IL-1Ra production. In addition, IL-13 reduced the level of IL-1 beta mRNA and stimulated the level of IL-1Ra mRNA. In synovial fibroblasts, IL-13 decreased the level of IL-1 binding, an effect related to the increased production of IL-1Ra. Although IL-13 had no effect on the TNF-R level, this cytokine markedly decreased the shedding of TNF-R75.

CONCLUSION

These experiments suggest that IL-13 is potentially useful in the therapeutic treatment of OA, as it could regulate the major pathological process of this disease by reducing the production of proinflammatory cytokines and metalloproteases, and favoring the production of IL-1Ra.

Two NSAIDs, nimesulide and naproxen, can reduce the synthesis of urokinase and IL-6 while increasing PAI-1, in human OA synovial fibroblasts

OBJECTIVES

To evaluate the effect of therapeutic and pharmacologic concentrations of two non-steroidal anti-inflammatory drugs (NSAIDs), nimesulide and naproxen, on the synthesis of urokinase (uPA), plasminogen activator inhibitor (PAI-1) and interleukin-6 (IL-6) in human synovial fibroblasts isolated from osteoarthritis (OA) patients.

METHODS

Urokinase, PAI-1, and IL-6 production were measured by specific ELISA.

RESULTS

Nimesulide and naproxen induced a dose-dependent decrease in uPA synthesis. The two drugs, at therapeutic concentrations, exerted a stimulatory effect on the synthesis of PAI-1 whereas the synthesis of IL-6 was significantly reduced by both NSAIDs.

CONCLUSION

The results of this study indicate some of the mechanisms by which nimesulide and naproxen could exert their effects on the arthritis process. The suppressive action of the two drugs on the synthesis of uPA, while stimulating PAI-1 production, may have a positive impact on the balance of plasminogen activator/inhibitor, which could help reduce cartilage catabolism.

The increased synthesis of inducible nitric oxide inhibits IL-1ra synthesis by human articular chondrocytes: possible role in osteoarthritic cartilage degradation

The degradation of osteoarthritic (OA) cartilage is likely related to the synthesis and the release of catabolic factors by chondrocytes. Nitric oxide (NO) has recently been suggested as playing a role in cartilage degradation. Since NO production is largely dependent on stimulation by IL-1, its effects on factors regulating the IL-1 biological activity, such as IL-1ra, are of the utmost importance. This study examined and compared the level of NO production by normal and OA cartilage and chondrocytes, as well as studied the effect of IL-1-induced NO production on the synthesis and steady-state mRNA of interleukin-1 receptor antagonist (IL-1ra). The NO baseline production by normal cartilage explants was undetectable but inducible by rhIL-1 beta. OA cartilage spontaneously produced NO. About a two-fold increase in NO production was found in OA rhIL-1 beta-stimulated (0.5-100 units/ml) cartilage as compared with the similarly stimulated normal cartilage. on chondrocytes rhIL-1 beta-stimulation (0.5-100 units/ml) produced a dose-dependent enhancement of both NO production and IL-1ra synthesis. Treatment with 200 microM N(g)-monomethyl-L-arginine (L-NMA), a well known NO synthase inhibitor, induced over 70% inhibition of the NO production and a marked increased IL-1ra synthesis (average of 84%) and expression (mRNA level). Inhibition of prostaglandin synthesis by indomethacin had no effect on both the NO production or the IL-1ra level. In the present study, we demonstrated the capacity of OA cartilage to produce a larger amount of NO than the normal controls, both in spontaneous and IL-1-stimulated conditions. These data support the notion that, in vivo, OA chondrocytes are stimulated by factors, possibly IL-1, which in turn may induce the expression of NO synthase, thus the synthesis of NO itself. Importantly, our results showed that the elevation of of NO production may be an important factor in the pathophysiology of OA since it can reduce IL-1ra synthesis by chondrocytes. As such, an increased level of IL-1, associated with a decreased IL-1ra level, may be responsible for the stimulation of OA chondrocytes by this cytokine, leading to an enhancement of cartilage matrix degradation.

Modulation of the Expression of Glucocorticoid Receptors in Synovial Fibroblasts and Chondrocytes by Prostaglandins and NSAIDs

Endogenous glucocorticoids are of prime importance in the maintenance of cellular homeostasis through their binding to specific cell receptors. Under normal conditions, physiological concentrations of cortisol are potentially capable of suppressing metalloprotease synthesis by chondrocytes and synoviocytes. This hormone action is like to represent one of the major pathways through which the catabolism of cartilage under physiological conditions is kept in a homeostatic state. In osteoarthritis (OA), a severe reduction (about 50%) in the glucocorticoid receptor (GR) level in chondrocytes was found to be sufficient to alter the cellular steroid resistance in terms of the synthesis of destructive enzymes. Prostaglandins of the E series and dibutyryl cyclic AMP increased the GR level in normal and OA human articular chondrocytes. Synthetic PGE(1) (misoprostol) also induced upregulation of GR expression in chondrocytes. Naproxen and indomethacin, but not tiaprofenic acid, at therapeutic concentrations, significantly reduced the level of GR in synovial cells. This effect could be reversed by the additionl of misoprostol. These findings bring insight into the differential effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on the GR system and may provide an explanation for the reduced level of GR found in OA chondrocytes. The addition of synthetic prostaglandins may prove to be of therapeutic importance in the treatment of arthritic diseases by potentiating the effects of therapeutically administered glucocorticoid on the reducation of the catabolism of articular cartilage.

Tenidap reduces the level of interleukin 1 receptors and collagenase expression in human arthritic synovial fibroblasts

OBJECTIVE

To investigate the effects of tenidap, a new antirheumatic drug, sodium diclofenac, a non-steroidal antiinflammatory drug, and a disease modifying antirheumatic drug, hydroxychloroquine, on the level and expression of interleukin 1 receptors (IL-1R) on synovial fibroblasts from patients with osteoarthritis (OA) and rheumatoid arthritis (RA). In addition, the effect of tenidap on IL-1 stimulated collagenase gene expression was studied.

METHODS

Binding assays were performed using [125I]-IL-1 beta as radioligand. Flow cytometry was done using a specific antibody against type I IL-1R. Protein synthesis was determined by [3H]-leucine incorporation. Levels of expression were determined by Northern Blot for collagenase and by reverse transcription polymerase chain reaction (RT-PCR) for type I IL-1R.

RESULTS

Tenidap produced for both OA and RA synovial fibroblasts a dose dependent decrease in the number of IL-1 binding sites/cell. A reduction of 41% (2.5 micrograms/ml) to 81% (at therapeutic concentration, 20 micrograms/ml) was noted for OA, while 29% (2.5 micrograms/ml) to 89% (20 micrograms/ml) was found for RA cells. Diclofenac produced no effect on OA cells, and minimal inhibition of RA synovial fibroblasts was observed only at pharmacological concentration (12%, 300 mg/ml). Hydroxychloroquine had effects similar to diclofenac. The decreased number of IL-1 binding sites/cell by tenidap was time dependent and reached 93% inhibition after 48 h. The effect of tenidap appears to be posttranscriptional, judged by the marked reduction of the type I IL-1R protein/cell and the absence of effect on its mRNA level. Tenidap also markedly reduced the IL-1 induced collagenase expression in synovial fibroblasts.

CONCLUSION

At therapeutic concentrations tenidap is a potent inhibitor of type I IL-1R in OA and RA synovial fibroblasts. The effect of tenidap was considerably more marked than diclofenac or hydroxychloroquine.

In vitro effects of 2 antirheumatic drugs on the synthesis and expression of proinflammatory cytokines in synovial membranes from patients with rheumatoid arthritis

OBJECTIVE

To compare the effects of tenidap, a new antirheumatic drug, with a nonsteroidal anti-inflammatory drug, naproxen, on the synthesis and expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor (TNF-alpha), and interleukin-6 (IL-6) in rheumatoid synovium.

METHODS

Human synovial membrane explants from patients with rheumatoid arthritis (RA) were incubated in the absence or presence of 20 micrograms/ml lipopolysaccharides (LPS) and tenidap at 50, 20 (therapeutic concentration), and 5 micrograms/ml or naproxen at 90 (therapeutic concentration) and 30 micrograms/ml. The levels of IL-1 beta, TNF-alpha, and IL-6 in the culture medium were measured by specific enzyme linked immunosorbent assays. The cytokine mRNA levels were quantitated by Northern blotting.

RESULTS

In the absence of LPS, tenidap at 20 micrograms/ml produced a significant (p < 0.04) decrease in the IL-1 synthesis level. Under LPS stimulation, IL-1 beta synthesis was inhibited by tenidap at all concentrations tested (p < 0.01) and by naproxen at only 90 micrograms/ml (p < 0.01). Very small amounts of TNF-alpha could be detected only when the synovial membranes were stimulated with LPS. Tenidap significantly reduced LPS stimulated TNF-alpha synthesis; the maximum inhibition was noted at 20 micrograms/ml (69%, p < 0.002). Naproxen, at 90 micrograms/ml, reduced TNF-alpha synthesis by about 40% (p < 0.03) and values were similar to those with subtherapeutic concentrations (5 micrograms/ml) of tenidap. The spontaneous and LPS induced synthesis of IL-6 was significantly inhibited by tenidap at all concentrations tested, whereas neither concentration of naproxen demonstrated a significant effect. Tenidap induced a somewhat similar reduction pattern of IL-1 beta and IL-6 mRNA to that observed for cytokine synthesis. Naproxen only slightly reduced the LPS induced expression of IL-6, while enhancing the IL-1 beta expression.

CONCLUSION

Tenidap and naproxen showed differences in their effects on cytokine synthesis and mRNA expression. Tenidap, at the therapeutic concentration, was most clearly differentiated from naproxen by its inhibition of IL-6, but was also a more potent modulator of IL-1 beta and TNF-alpha in RA synovial explants. The significance of these findings lies in the possible therapeutic benefit of proinflammatory cytokine suppression in joint disease.

The reduced expression of glucocorticoid receptors in synovial cells induced by nonsteroidal antiinflammatory drugs can be reversed by prostaglandin E1 analog

OBJECTIVE

We examined the effect of 3 commonly used nonsteroidal antiinflammatory drugs (NSAID), indomethacin, naproxen and tiaprofenic acid, and a prostaglandin E1 analog, misoprostol, on the glucocorticoid receptor level in synovial fibroblasts.

METHODS

Synovial fibroblasts were isolated by enzymatic digestion from human normal synovial membranes. These cells were incubated with therapeutic and pharmacological concentrations of NSAID in the presence or absence of misoprostol (0.1-100 ng/ml). The glucocorticoid receptor (GR) level was measured by binding assay using 3H-dexamethasone.

RESULTS

Naproxen and indomethacin but not tiaprofenic acid, at therapeutic concentrations, significantly reduced the level of GR in synovial cells. This effect was reversed with the addition of misoprostol.

CONCLUSION

Our findings bring insight into the differential effects of NSAID on the GR system and may provide an explanation for the reduced level of GR found in OA chondrocytes. The possible interference with the action of therapeutically administered corticosteroids is discussed.

Altered elastin and collagen synthesis associated with progressive pulmonary hypertension induced by monocrotaline. A biochemical and ultrastructural study

Changes in elastin and collagen synthesis in the pulmonary artery wall, assessed both biochemically and ultrastructurally, were related to the development of progressive pulmonary hypertension induced by the toxin monocrotaline. Male Sprague-Dawley rats (200 to 225 gm) were injected subcutaneously in the hind flank with either monocrotaline (60 mg/kg) or an equivalent volume of saline and studied 8, 16 and 28 days later. At each time point, the right ventricle and left ventricle with septum were separated and weighed to follow the development of right ventricular hypertrophy. The hilar pulmonary artery was assessed by light microscopy for medial hypertrophy and by electron microscopy for changes in the endothelium, subendothelium and media. The mainstem pulmonary artery was used to determine synthesis of elastin and collagen by in vitro incorporation of [14C]proline into nonelastin, [14C]hydroxyproline into collagen, and [3H]valine into cyanogen bromide-insoluble elastin. In addition, total content of insoluble elastin was determined by weight of the residue after cyanogen bromide digestion and of collagen by total hydroxyproline content in sodium dodecyl sulfate and cyanogen bromide extracts. Eight days after monocrotaline injection, there was pulmonary artery endothelial swelling and a significant decrease in the number of myoendothelial junctions (p less than 0.05) associated with a decreased proportion of amorphous elastin in the media (p less than 0.01). Sixteen days after monocrotaline injection, a decrease in the proportion of elastin in the media was still evident (p less than 0.01) despite an apparent increase in insoluble elastin synthesis. Moreover, the amorphous elastin was distributed preferentially in small islands rather than in laminae (p less than 0.05). Twenty-eight days after monocrotaline injection, medial and right ventricular hypertrophy had developed (p less than 0.05 and p less than 0.01, respectively). At the same time, there was a striking increase in both insoluble elastin synthesis and total insoluble elastin content (p less than 0.01 for both) and an increase in collagen synthesis and total collagen content (p less than 0.05 for both). In addition, the ratio of insoluble elastin synthesis to collagen synthesis was greater than in controls (p less than 0.01), whereas the ratio of total insoluble elastin to total collagen did not change. On ultrastructural analysis, the proportion of amorphous elastin in the vessel wall relative to other elements remained low (p less than 0.01) and was distributed throughout the media as increased numbers of small islands (p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)