Biomechanical improvements in gait following medial pivot knee implant surgery.

BACKGROUND: Total knee replacements are used to improve function and reduce pain in patients with advanced osteoarthritis. The medially stabilising implant is designed to mimic a healthy knee. This study aims to provide a comprehensive analysis of the kinematics and kinetics of a medially stabilising knee implant, comparing it to a healthy control group, as well as to its pre-operative state and the contralateral limb. METHODS: Sixteen total knee replacement patients and ten healthy participants were recruited. Patients underwent testing 4-6 weeks before surgery and repeated the same tests 12 months after surgery. Healthy participants completed the same tests at a single time point. All participants completed three walking trials: kinematics was captured with eight cameras; kinetics with in-ground force plates. Subject-specific musculoskeletal models were developed in OpenSim. Inverse kinematics and inverse dynamics were used to determine gait parameters. Joint angles and joint moments were evaluated using Statistical Parametric Mapping. Patient-reported outcome measures were also collected at both time points. FINDINGS: Spatiotemporal results indicate significant differences in velocity and step length between pre-operative patients and control participants. Differences are observed in the adduction angles between the contralateral and ipsilateral limbs pre-operatively. Postoperatively, there was an increase in the 1st peak flexion moment, reduced adduction moment and reduced internal rotation moment. In PROMs, patients all report improvements in pain levels and high satisfaction levels following surgery. INTERPRETATIONS: Following medial stabilising total knee arthroplasty, patients displayed improved clinical parameters and joint moments reflecting a shift towards more normal, healthy gait.

CommEmorating the Last Event: calling time on the end of treatment Bell following RAdioThErapy? The CELEBRATE study.

INTRODUCTION: In the UK it is commonplace for patients completing radiotherapy to be invited to ring a bell as a form of celebration. The project aimed to explore the experiences of the end of treatment bell from the perspective of patients who had received treatment for cancer, and therapeutic radiographers who treat patients. The study also aimed to consider possible alternative methods of commemorating the EoT, considering the needs of patients, family members and healthcare professionals. METHODS: Online focus groups were held with patients (n = 5) and therapeutic radiographers (n = 4) in December 2020; a joint online event (n = 6) was held in March 2022. They were all facilitated by two members of the research team. Thematic analysis was used for data analysis. RESULTS: Participants' views and experiences were mixed; however, there was a consensus that alternative forms of commemoration should be available to meet patients' diverse needs. Features of a specification were considered and suggestions made for alternative practices, with a focus upon patients' transition needs after radiotherapy has ended. CONCLUSION: The results indicate that departments should consider the harms as well as the benefits conferred by the EoT bell and explore alternative ways to mark an episode of treatment. IMPLICATIONS FOR PRACTICE: A one-size-fits-all approach is not appropriate in relation to marking the end of an episode of treatment.

Retention of radiographers in the NHS: Influencing factors across the career trajectory.

INTRODUCTION: In order to meet the rising demands for imaging and radiotherapy services, the chronic workforce deficits experienced in many countries must be addressed. Improving workforce retention is essential; factors influencing radiographer attrition from the NHS have been previously reported as challenging working patterns, lack of flexibility in working patterns and lack of timely career progression and CPD. This article explores how these influencing factors for radiographers to leave the NHS change at different stages of the career trajectory. METHODS: A qualitative research design using framework analysis explored via semi-structured telephone interviews (n = 44) the perspectives of radiography managers, radiographers who have left the NHS, and those considering leaving. Purposive sampling ensured representation across radiography disciplines, geographical and organisational diversity, and stages of career. RESULTS: The application of Generation Theory revealed how the emphasis on the influencing factors to leave or remain within the NHS changes across the working life of radiographers. Early career radiographers were found to be a more transient workforce leaving for increased career opportunities, mid-career radiographers were more likely to leave due to the lack of progression and CPD and late career radiographers due to the inflexibility of working patterns and conditions. It is imperative managers consider the needs and requirements of each generation of radiographers to improve radiographer retention. CONCLUSIONS: The different needs between the generations of radiographers should be viewed in terms of the strengths that they may bring to the workplace, rather than the challenges that they may pose. This generational timeline does not stand still and the learning is a continuous process. IMPACT ON PRACTICE: Recommendations are presented which will be a catalyst for sharing of best practice between radiology and radiotherapy centres.

Gender diversity in therapeutic radiography: A mixed methods exploration of the gender influences impacting on male students' career choices.

INTRODUCTION: A significant gender imbalance exists in therapeutic radiography, with male radiographers contributing to less than one fifth of the UK registered workforce. This research aimed to explore male student recruitment experiences to identify gender-sensitive strategies to employ within future recruitment drives. METHODS: An exploratory mixed methods design commenced with therapeutic radiography student focus groups, analysed via descriptive thematic analysis. The focus group themes informed an online questionnaire survey targeting enrolled male therapeutic radiography students in the UK. Both phases explored students' experiences of their career choice and the impact, if any, their gender had on this selection. RESULTS: Three focus groups (n = 9) yielded four major themes: the invisible profession; career choices; gender influences; gender-sensitive approaches. Survey responses (n = 38) represented 9 UK institutions, a 25% estimated response rate. Over half (55%) had little or no awareness of the career at entry, with many discovering the profession 'by accident'. Many had never seen recruitment materials; 40% (n = 15) stated they were not designed to appeal to male applicants, with 18% (n = 7) suggesting they reflected more stereotypical female traits. CONCLUSION: Targeting gender imbalances is always controversial but doing nothing will maintain the status quo and perpetuate an unrepresentative workforce. Earlier awareness-raising of therapeutic radiography is essential, with promotional imagery suitable for different audiences and focusing equally on care and technology. Recruitment language should embrace 'leadership' attributes as well as 'caring' attributes. Supported by male role models, outreach events should emphasise the profession in terms of a sustainable, fulfilling and rewarding career. IMPLICATIONS FOR PRACTICE: The findings have provided detailed recommendations on which to focus a specific recruitment and marketing strategy to encourage male applicants to consider a career in therapeutic radiography.

Retention of radiographers: A qualitative exploration of factors influencing decisions to leave or remain within the NHS.

INTRODUCTION: In many countries a widening imbalance exists between radiographer workforce supply and demand. Improving retention is a rapid method of workforce expansion which is gaining importance with policy makers and providers. To better understand the current leaver profile, this study aimed to identify why radiographers leave the NHS early, and what incentives are important in their decision to stay. METHODS: A qualitative framework methodology used semi-structured telephone interviews to explore the perspectives of radiography managers, radiographers who have left the NHS, and those considering leaving. Purposive sampling ensured representation across radiography professional groups, geographical and organisational diversity, and stages of career. RESULTS: Three over-arching themes were identified across all radiographer professional groups (n = 44): 1) Challenging working patterns and the impact on employee health and wellbeing; 2) Lack of flexibility in working terms and conditions; 3) Lack of timely career progression and access to CPD, and the need to feel valued. Radiographers were keen to express how they 'loved being a radiographer'; small concessions and changes to workplace culture might be the incentive to remain in radiography that some were clearly searching for. Manager participants recognised the need to offer greater flexibility in working patterns but this was challenging within financial and service delivery constraints. CONCLUSIONS: While some influencing factors varied between radiographer professional groups, the three themes were consistent across participants. Failure to address these concerns will exacerbate the loss of experienced and highly trained staff from the NHS at a time when demand for services continues to rise. IMPACT ON PRACTICE: Recommendations are presented related to three primary themes which will be a catalyst for sharing of best practice between radiology and radiotherapy centres.

Reamed locked intramedullary nailing for studying femur fracture and its complications.

Morbidity associated with femur fractures in polytrauma patients is known to be high. The many unsolved clinical questions include the immunological effect of the fracture and its fixation, timing of fracture fixation, management of fracture non-union, effect of infection and critical size of bone defects. The aim of this study was to establish a clinically-relevant and reproducible animal model with regards to histological, biomechanical and radiological changes during bone healing. A custom-designed intramedullary nail with interlocking system (RabbitNail, RISystem AG, Davos Platz, Switzerland) was used for fixation, following femur fracture. New Zealand White rabbits were assigned to two groups: 1. closed fracture model (CF; non-survival model: n = 6, survival model: n = 3) with unilateral mid-shaft femur fracture created by blunt force; 2. osteotomy model (OT; survival model: n = 14) with unilateral transverse osteotomy creating femur fracture. There were no intraoperative complications and full-weight bearing was achieved in all survival rabbits. Significant periosteal reaction and callus formation were confirmed from 2 weeks postoperatively, with a significant volume formation (739.59 ± 62.14 mm3) at 8 weeks confirmed by micro-computed tomography (µ-CT). 2 months after fixation, there was no difference between the osteotomised and contralateral control femora in respect to the maximum torque (3.47 ± 0.35 N m vs. 3.26 ± 0.37 N m) and total energy (21.11 ± 3.09 N m × degree vs. 20.89 ± 2.63 N m × degree) required to break the femur. The data confirmed that a standardised internal fixation technique with an intramedullary nail for closed fracture or osteotomy produced satisfactory bone healing. It was concluded that important clinically-relevant studies can be conducted using this rabbit model.

A randomised controlled trial comparing meat-based with human cadaveric models for teaching ultrasound-guided regional anaesthesia.

The aim of this prospective, blinded, randomised controlled study was to compare novices' acquisition of the technical skills of ultrasound-guided regional anaesthesia using either a meat phantom model or fresh-frozen human cadavers. The primary outcome was the time taken to successfully perform an ultrasound-guided sciatic nerve block on a cadaver; secondary outcomes were the cumulative score of errors, and best image quality of the sciatic nerve achieved. After training, the median (IQR [range]) time taken to perform the block was 311(164-390 [68-600]) s in the meat model trained group and 210 (174-354 [85-600]) s in the fresh-frozen cadaver trained group (p = 0.24). Participants made a median (IQR [range]) of 18 (14-33 [8-55]) and 15 (12-22 [8-44]) errors in the two groups respectively (p = 0.39). The image quality score was also not different, with a median (IQR [range]) of 62.5 (59.4-65.6 [25.0-100.0])% vs 62.5 (62.5-75.0 [25.0-87.5])% respectively (p = 0.58). The training and deliberate feedback improved all participants' block performance, the median (IQR [range]) times being 310 (206-532 [110-600]) s before and 240 (174-354 [85-600]) s after training (p = 0.02). We conclude that novices taught ultrasound scanning and needle guidance skills using an inexpensive and easily constructed meat model perform similarly to those trained on a cadaveric model.

Effects of bioactive glass nanoparticles on the mechanical and biological behavior of composite coated scaffolds.

Biphasic calcium phosphates (BCP) scaffolds are widely used for bone tissue regeneration. However, brittleness, low mechanical properties and compromised bioactivities are, at present, their major disadvantages. In this study we coated the struts of a BCP scaffold with a nanocomposite layer consisting of bioactive glass nanoparticles (nBG) and polycaprolactone (PCL) (BCP/PCL-nBG) to enhance its mechanical and biological behavior. The effect of various nBG concentrations (1-90 wt.%) on the mechanical properties and in vitro behavior of the scaffolds was comprehensively examined and compared with that for a BCP scaffold coated with PCL and hydroxyapatite nanoparticles (nHA) (BCP/PCL-nHA) and a BCP scaffold coated with only a PCL layer (BCP/PCL). Introduction of 1-90 wt.% nBG resulted in scaffolds with compressive strengths in the range 0.2-1.45 MPa and moduli in the range 19.3-49.4 MPa. This trend was also observed for BCP/PCL-nHA scaffolds, however, nBG induced even better bioactivity and a faster degradation rate. The maximum compressive strength (increased ∼14 times) and modulus (increased ∼3 times) were achieved when 30 wt.% nBG was added, compared with BCP scaffolds. Moreover, BCP/PCL-nBG scaffolds induced the differentiation of primary human bone-derived cells (HOBs), with significant up-regulation of osteogenic gene expression for Runx2, osteopontin and bone sialoprotein, compared with the other groups.

Effects of positioning and notching of resurfaced femurs on femoral neck strength: a biomechanical test.

PURPOSE: To assess the effects of positioning and notching of resurfaced femurs on the mechanical strength of third-generation saw bone (TGSB) femurs using an in vitro analogue bone model. METHODS: 30 TGSB femurs were equally divided into 6 resurfaced femur groups (intact, anatomic, varus, valgus, anatomically notched, and valgus notched) for testing the load to failure, stiffness, and total energy. RESULTS: Compared to the intact femurs, the load to failure in all resurfaced femurs was significantly decreased by 29 to 57%. Among the resurfaced femurs, valgus and anatomic femurs had the highest load to failure, followed by valgus notched, varus, and anatomically notched femurs. Notching weakened the construct by a further 24 to 30%. CONCLUSION: To minimise the risk of femoral neck fracture, resurfaced femoral heads should be placed in an anatomic or valgus orientation, and the superior cortex of the femoral neck should remain intact.

An evaluation of prosthetic femoral head impact on acetabular articular cartilage in a hemiarthroplasty model.

OBJECTIVES: The quantitation of the impact of hemiarthroplasty currently involves clinical outcome measures and radiographic evaluation. This study used in vivo and in vitro means in order to evaluate articular cartilage changes following hemiarthroplasty in the sheep. METHODS: Radiostereometric analysis (RSA) was utilized in order to quantitate migration (penetration) in vivo of the femoral head into the articular cartilage of the acetabulum. Dynamic stiffness of retrieved specimens was quantitated in vitro using a handheld device. Chondrocyte viability was assessed using live/dead cell staining and quantitated using image analysis techniques. Saffranin-O staining provided histological assessment of the cellular response to hemiarthroplasty. RESULTS: RSA showed rapid penetration of the femoral head into the acetabular cartilage over six months. Significantly higher levels of dynamic stiffness were observed in the acetabula following hemiarthroplasty. Confocal imagery highlighted changes in chondrocyte distribution and morphology. A loss of metachromasia, fibrovascular tissue invasion and apoptosis were observed histologically. CONCLUSIONS: RSA and measurement of the dynamic mechanical characteristics of cartilage provide a means of evaluating the development of degenerative articular cartilage changes in response to hemiarthroplasty.

Modulation of aggrecan and ADAMTS expression in ovine tendinopathy induced by altered strain.

OBJECTIVE: To evaluate histologic, immunohistochemical, and molecular changes in tendon induced by altered strain in a large-animal model. METHODS: A full-thickness partial-width laceration of the infraspinatus tendon was created in 5 sheep, while 5 sham-operated sheep were used as controls. Sheep were killed after 4 weeks, and 4 differentially stressed tendon regions (tensile or near bone attachment from overstressed or stress-deprived halves) were evaluated for histopathology, proteoglycan (PG) accumulation, and characterization of glycosaminoglycans and aggrecan catabolites. Gene expression of matrix components, enzymes, and inhibitors was analyzed by reverse transcriptase-polymerase chain reaction. RESULTS: Histopathologic changes were detected in both overstressed and stress-deprived tensile tendon, but only in stress-deprived tendon near bone. In overstressed and stress-deprived tensile tendon, levels of keratan sulfate, chondroitin 4-sulfate, and chondroitin 6-sulfate were increased. In overstressed tensile tendon, levels of ADAMTS-generated aggrecan catabolites were increased. There was increased matrix metalloproteinase 13 (MMP-13) and decreased fibromodulin and decorin expression in all regions. Increased MMP-1, MMP-9, MMP-14, and ADAMTS-1 expression, and decreased type II collagen expression were restricted to stress-deprived tendon. In stress-deprived bone-attachment regions, messenger RNA (mRNA) for aggrecan was decreased, and ADAMTS was increased. In overstressed tensile tendon, aggrecan mRNA was increased, and ADAMTS was decreased. CONCLUSION: The distinct molecular changes in adjacent tissue implicate altered strain rather than humoral factors in controlling abnormal tenocyte metabolism, and highlight the importance of regional sampling. Tendon abnormalities induced by increased strain are accompanied by increased aggrecan, decreased ADAMTS, and low PG expression, which may negatively impact the structural integrity of the tissue and predispose to rupture.

Reliability of a new shoulder laxometer to assess inferior glenohumeral joint translation.

OBJECTIVE: This study tested the reliability of the ORI laxometer, a newly developed non-invasive device for testing inferior translation of the humeral head in humans. DESIGN: The instrument was designed to measure displacement between the top of the acromion and the head of the humerus when loaded in a similar fashion to the sulcus sign. PARTICIPANTS AND INTERVENTIONS: Sixteen healthy subjects (32 shoulders) were measured for inferior glenohumeral joint laxity. One observer used the laxometer in 16 subjects on three separate occasions for the intra-observer trial. Three observers measured the inferior shoulder laxity of six subjects on one occasion in the inter-observer trial. Asymptomatic and unstable shoulders were also compared in 12 subjects with shoulder instability. MAIN OUTCOME MEASUREMENTS: Translation in the glenohumeral joint RESULTS: The range of inferior translation of glenohumeral joint in these subjects was between 0.01 mm and 6.5 mm with a mean of 1.5 mm. The intraclass correlation coefficient (ICC) for inter-observer reliability was 0.74. For intra-observer reliability the ICC was 0.76. These results are considered to be good to excellent. There was no advantage gained by using data from all five cycles of testing compared with three cycles. In patients with shoulder instability, laxometer measurements were significantly greater in their unstable shoulders than in their normal shoulders. CONCLUSIONS: The laxometer is easy to use, painless and gives objective measures for inferior glenohumeral laxity, with good intra- and inter-observer reliabilities. The ORI laxometer may be useful for assessing and monitoring global glenohumeral joint laxity which usually involves inferior laxity.

Arthroscopic estimation of the extent of chondropathy.

INTRODUCTION: Arthroscopy has been used to evaluate articular cartilage (AC) pathology in osteoarthritis (OA) for outcome measurement and validation of non-invasive imaging. However, many fundamental aspects of arthroscopic assessment remain un-validated. OBJECTIVES: This study evaluated arthroscopic estimates of extent of chondropathy. METHODS: Serial arthroscopic assessments were performed in a group of 15 sheep before and after bilateral stifle medial meniscectomy (MMx). Post-mortem assessments were performed in un-MMx sheep and 4 and 16 weeks post-MMx. Arthroscopic assessments of the extent of each grade of chondropathy were compared with a non-arthroscopic hybrid assessment that incorporated biomechanical, thickness and macroscopic assessments. RESULTS: Arthroscopy evaluated only 36% of AC and missed significant pathological changes, softening and chondro-osteophyte, occurring in peripheral regions. The patterns of change in arthroscopic assessments were similar to those of the non-arthroscopic assessment but there was a very strong tendency to over-estimate the extent of softened AC after MMx. In spite of these limitations arthroscopic assessments were responsive to change. Estimates of the extent of normal and softened AC were most responsive to change over time followed by estimates of superficial and deep fibrillation. Arthroscopy was as an excellent discriminator between normal and OA. Assessments of chondro-osteophyte and exposed bone were not responsive to change. CONCLUSIONS: Arthroscopic estimates of extent of chondropathy are prone to substantial error. While experience and training may reduce these errors other approaches may more effectively improve performance.

Spontaneous recovery of injured Achilles tendon in inducible nitric oxide synthase gene knockout mice.

OBJECTIVE AND DESIGN: To determine if inducible nitric oxide synthase (iNOS) gene could affect Achilles tendon healing using iNOS gene knockout mice. METHODS: 21 iNOS knockout (iNOS(-/-)) mice and 8 of the wild type (iNOS(+/+)) mice were utilized in this study. Group 1: iNOS(+/+) mice (n = 8), group 2: iNOS(-/-) mice (n = 11) and group 3: iNOS(-/-) with a NOS inhibitor, (aminoguanidine, 500 mg/kg/day, via an intraperitoneal mini-osmotic pump for 7 days, n = 10). The right Achilles tendon was transected in all mice and harvested on day 7 for cross-sectional area and biomechanical properties. Serum nitrate concentration of the mice was measured by gas chromatography mass spectrometry (GC/MS). RESULTS: A significant reduction in cross-sectional area of the healing Achilles tendon was observed in group 3 mice compared to group 2 mice (p < 0.01). The serum nitrate concentration in both group 2 and group 3 mice was lower than that in group 1 mice (p < 0.01) iNOS gene deletion and inhibition of NOS did not affect the biomechanical properties of the healing tendons. CONCLUSIONS: iNOS gene is not solely responsible for the beneficial effects of nitric oxide (NO) on tendon healing.

Overexpression of nitric oxide synthases in tendon overuse.

Tendon disorders with a chronic nature, including the rotator cuff, are extremely common, and represent a major clinical problem. Mechanical overload has been proposed as an important etiologic factor in tendinopathies. Nitric oxide (NO), a free radical produced by nitric oxide synthases (NOSs), is a potent regulator and stimulator of biological processes including tendon degeneration and healing. It is also involved in response to mechanical stimuli in different tissues. In an animal model of acutely injured tendon healing temporal and differential expression of NOS isoforms has been demonstrated, suggesting that different patterns of NOSs expression may have different biological functions. Therefore, we hypothesized that tendon overuse may result in a differential upregulation of NOSs, particularly iNOS. An animal model of supraspinatus tendon overuse was utilized, which consisted of treadmill running. A group of animals of the same strain and age subjected to normal cage activity were used as controls. Following a 4-week exercise protocol supraspinatus tendons were harvested, RNA was extracted, and subjected to competitive reverse transcription and polymerase chain reaction (RT-PCR) to determine the expression levels of inducible-, endothelial-, and neuronal-NOS isoforms (i-, e-, and nNOS). The mRNA expression of all three NOS isoforms increased in the supraspinatus tendons as a result of overuse exercise. iNOS and eNOS mRNA expression increased fourfold (p < 0.01), and there was an increase, but statistically not significant, in nNOS mRNA expression in the overused tendons when compared with the controls. This study is the first to show that NOS isoforms are upregulated in rotator cuff tendon as a result of chronic overuse, and suggests the involvement of nitric oxide in the response of tendon tissue to increased mechanical stress.

Ovariectomy alters the structural and biomechanical properties of ovine femoro-tibial articular cartilage and increases cartilage iNOS.

OBJECTIVE: To examine the effect of oestrogen depletion produced by surgical ovariectomy on the structural and biomechanical properties of ovine femoro-tibial articular cartilage (AC), and the production of inducible nitric oxide synthase (iNOS) and nitrotyrosine by these tissues. METHODS: Six aged ewes were surgically ovariectomised (OVX), while six were used as unoperated controls. Dynamic biomechanical indentation testing of tibial plateau AC was performed at 26 weeks post-op. Histological sections of medial tibial plateau and lateral tibial plateau (LTP), medial and lateral femoral condyles (MFC, LFC) and patellar AC were examined for histopathology, toluidine blue staining intensity, and patterns of collagen birefringence intensity. Immunoreactivity for iNOS and nitrotyrosine was assessed in full-thickness biopsy plugs of LFC and patellar AC, and patellar AC explants were cultured to determine in vitro NO release. RESULTS: Phase lag was reduced overall in LTP-AC of OVX sheep (10.9+/-2.2 degrees vs 12.1+/-2.3 degrees ; P<0.0001). Cartilage thickness was reduced in the LTP of OVX sheep (P=0.0002), in association with localised changes in dynamic shear modulus. Toluidine blue staining intensity was reduced in the patella, LFC, and MFC. Histological examination revealed greater histopathology scores in the MFC of OVX animals, and altered collagen birefringence intensity plots in the LTP. Immunostaining for iNOS was increased in patella AC (P=0.008), whilst nitrotyrosine immunoreactivity was increased in patella (P=0.03) and LFC (P<0.0001) AC. NO release by patellar AC explants was also elevated. CONCLUSIONS: Oestrogen depletion induced by OVX caused regional thinning of femoro-tibial cartilage, with biomechanical and histological changes suggestive of a disturbance in the content and/or structural organisation of the proteoglycan and collagen macromolecular assembly. The observed up-regulation of cartilage iNOS suggests a possible mechanism for these matrix changes.

Arthroscopy -- a potential "gold standard" for the diagnosis of the chondropathy of early osteoarthritis.

OBJECTIVES: The aims of this study were to: 1. Evaluate the performance of arthroscopy for the diagnosis of chondropathy and to compare it to that of direct non-arthroscopic assessments; 2. Determine intra-observer reliability of arthroscopic assessments; 3. Evaluate the effects of the arthroscopic video quality and probing upon diagnostic performance. DESIGN: The ovine medial meniscectomy (MMx) model of early osteoarthritis (OA) was used assuming that pre-MMx articular cartilage (AC) was "normal" and post-MMx AC "chondropathic". Video recordings of arthroscopic assessments of each stifle compartment were evaluated. Scores were given for the quality of the video and the amount of probing. The diagnostic performances of dynamic shear modulus (G), light microscopic assessment and superficial zone collagen birefringence assessments were evaluated and compared to that of arthroscopy. Intra-observer reliability of arthroscopic assessments was also evaluated. RESULTS: Arthroscopic assessments had high sensitivity (91-100%), specificity (62-88%) and accuracy (75-93%) for the diagnosis of chondropathy 16 weeks after MMx. Arthroscopy compared favourably with the direct non-arthroscopic assessments in the lateral compartment and was found to have extremely high intra-observer reliability (kappa 0.78-1.00). The quality of arthroscopic video recordings and the amount of probing did not significantly influence accuracy or reliability. CONCLUSIONS: Arthroscopy performs as well as direct non-arthroscopic assessments of AC for diagnosis of early OA. These results suggest that arthroscopy can be used as a "gold standard" for the validation of non-invasive assessments like magnetic resonance imaging and that arthroscopic diagnosis can be based on small amounts of video footage without AC probing.

Biomechanical, histologic and macroscopic assessment of articular cartilage in a sheep model of osteoarthritis.

OBJECTIVES: Our primary objective was to explore the full potential of the ovine medial meniscectomy (MMx) model of early osteoarthritis (OA) for studies to validate non-destructive articular cartilage (AC) assessments and therapeutic interventions. Our secondary objective was to re-evaluate the relationships between the different types of AC assessment after MMx in sheep. METHODS: Macroscopic assessments, dynamic shear modulus (G*), phase lag and AC thickness measurements were performed at a total of 5437 reference points on all six articular surfaces in four normal joints and 16 MMx ovine stifle (knee) joints. Comparisons with histologic assessments of gross structural damage, collagen organisation (birefringence) and proteoglycan content were possible at 702 of these points. RESULTS: Histologic gross structural damage and proteoglycan loss were seen throughout the joint with greatest severity (fibrillation) in closest proximity to the MMx site. Increases in AC (30-50%) thickness, reductions in G* (30-40%) and collagen birefringence intensity (15-30%) occurred more evenly throughout the joint. Macroscopic softening was evident only when G* declined by 80%. G* correlated with AC thickness (rho=-0.47), collagen organisation rho=0.44), gross structural damage (rho=-0.44) and proteoglycan content (rho=0.42). Multivariate analysis showed that collagen organisation contributed twice as much to dynamic shear modulus (t=6.66 as proteoglycan content (t=3.21). Collagen organisation (rho=0.11) and proteoglycan content (rho=0.09) correlated only weakly to phase lag. CONCLUSIONS: Macroscopic assessments were insensitive to AC softening suggesting that arthroscopic assessments of AC status might also perform poorly. Collagen integrity was more important for the maintenance of AC stiffness (G*) than proteoglycan content. The development of major AC softening and thickening throughout the joint following MMx suggested involvement of non-mechanical (e.g., protein and biochemical) chemical and cytokine mediated processes in addition to the disturbance in biomechanical loading. The ovine MMx model provides a setting in which the spectrum of AC changes associated with the initiation and progression of OA may be evaluated.

Topical administration of the nitric oxide donor glyceryl trinitrate modifies the structural and biomechanical properties of ovine articular cartilage.

OBJECTIVE: To examine the effect of topical administration of glyceryl trinitrate (GTN), an exogenous nitric oxide (NO) donor, on the structural and biomechanical properties of uncalcified articular cartilage (UCC) in aged ewes. DESIGN: Twelve ewes were used for this study. Six of these were treated with 2% GTN ointment (0.7 mg/kg) twice per week (GTN), and the remaining six were used as normal controls (NOC). After sacrifice at 26 weeks, dynamic biomechanical indentation testing and thickness determination (by needle penetration) were performed on tibial plateau articular cartilage at 18 locations. Using histological sections prepared from the lateral and medial femoral condyles (LFC, MFC) and tibial plateau (LTP, MTP), the thickness of UCC, cartilage proteoglycan content (intensity of toluidine blue staining; LFC, MFC only), and collagen birefringence (LTP, MTP, LFC only) were quantified by computer-assisted image analysis. RESULTS: Phase lag of tibial plateau cartilage was reduced in GTN sheep relative to NOC (mean of all testing locations 11.0+/-1.9 degrees vs 12.1+/-2.3 degrees; P=0.0001). GTN treatment also globally reduced UCC thickness across the joint (ANOVA for all measured zones, P<0.0001). UCC thinning was most pronounced in the MFC (P=0.025) and LTP (P=0.0002). Proteoglycan content was reduced in the MFC(P=0.019), while collagen birefringence was increased in superficial cartilage zones of the LTP. CONCLUSIONS: NO donation via topical administration of GTN to normal ewes reduced the thickness and phase lag of femoro-tibial articular cartilage, suggesting a disturbance in chondrocyte metabolism. Regional alterations of collagen organisation and proteoglycan content were consistent with this interpretation.

Addition of nitric oxide via nitroflurbiprofen enhances the material properties of early healing of young rat Achilles tendons.

OBJECTIVE AND DESIGN: To determine if the addition of nitric oxide (NO) via nitroflurbiprofen (NO-flurbiprofen) would enhance rat Achilles tendon healing. MATERIALS AND METHODS: Sixty-five male Sprague-Dawley rats were randomly divided into NO-flurbiprofen, flurbiprofen and vehicle groups, given drugs or vehicle subcutaneously, and their right Achilles tendon divided. Histological assessment was carried out at day 5, 10, and 15 post-operation. Healing tendon biomechanical properties and hydroxyproline content were measured at day 10. RESULTS: The healing Achilles tendon from the NO-flurbiprofen and flurbiprofen groups showed a better organization of extracellular collagenous matrix than that from the vehicle group. Flurbiprofen and NO-flurbiprofen decreased healing tendon cross-sectional area by 30% and 20%. This reduction was accompanied by a decreased failure load in the flurbiprofen group, but not the NO-flurbiprofen group. NO-flubiprofen prevented the reduction of body weight gain observed in the flubiprofen group. CONCLUSION: Both flurbiprofen and NO-flurbiprofen promoted better collagen reorganization during tendon healing. NO-flurbiprofen further improved tendon healing by increasing tendon stress and reducing the side effects (body weight loss) of flurbiprofen. The enhanced tendon healing by NO-flurbiprofen is likely due to the release of NO from the compound.