Comparison of Different Methods of Semiquantitative Assessment and Subjective Scores for Retropatellar Articular Cartilage Evaluation in Advancing Osteoarthritis

BACKGROUND

cartilage layer thickness, composition of the extracellular matrix (ECM), geometry and configuration of retropatellar cartilage partially differ significantly from those found at other locations and are essential for patellofemoral biomechanics.

MATERIAL AND METHODS

119 serial medial and lateral patella facet samples of patients undergoing implantation of a total knee endoprosthesis of areas showing mild (Group A, macroscopically ICRS Grade 1b) respectively advanced (Group B, macroscopically ICRS Grade 3a/3b) (38 each) osteoarthritis according to the histological-histochemical grading system (HHGS) were compared with 22 healthy biopsies by means of immunohistochemistry and histology investigations. We quantified our results on the gene expression of collagen type I and II and aggrecan with real-time (RT)-PCR rsp using colourimetry for proteoglycan content. The digitized images of histology and immunohistochemistry staining with Safranin O, Alcian blue, PAS, Masson Goldner, immunostaining, e.g. for collagen I and II were also analyzed with Photoshop software.

RESULTS

The most significant decrease in staining intensity was revealed for Safranin-O staining in Group B at the lateral patellar facet, and the most relevant increase was for Col I staining at the same site. The lateral patella site in Group B also showed the highest increase in the ratio of expression indices for the genes Col1A1 and the reference gene following the equation 2-ΔCt with a quotient of 29.6.

CONCLUSIONS

1. Comparisons of our retropatellar cartilage analysis with femoral and tibial studies utilizing similar techniques show significant differences. 2. Cartilage layer thickness, ECM composition, geometry and configuration are essential for patellofemoral biomechanics. 3. Consequently, there is a need for diversified approaches towards retropatellar surface during TKA as well as for advanced cartilage restoration techniques.

Impact of a Six-Week Prehabilitation With Blood-Flow Restriction Training on Pre- and Postoperative Skeletal Muscle Mass and Strength in Patients Receiving Primary Total Knee Arthroplasty

Introduction: Total Knee Arthroplasty (TKA) is one of the most successful interventions in gonarthrosis, however the operation is leading to muscle atrophy and long-term muscular deficits. To enhance rehabilitation after TKA, exercise programs try to improve muscle function preoperatively, called prehabilitation. Blood-Flow-Restriction Exercises (BFRE) is a training method which is characterized by using tourniquets to reduce arterial and occlude venous blood flow simultaneously during the exercise to increase metabolic stress. The present study aimed to evaluate the effects of a 6-week prehabilitation with BFR on pre- and postoperative muscle mass, strength, and quality of life (QoL).

Methods: 30 patients with end-stage gonarthrosis participated in this study. Patients were randomized into one of three groups: 1) Control-Group (CON): Standard clinical approach without prehabilitation. 2) Active-Control-Group (AC): Participation in a prehabilitation with sham-BFR. 3) BFR-Group (BFR): Participation in a prehabilitation with BFR. The prehabilitation protocol consist of a cycling-ergometer-based training performed twice per week over 6 weeks. During exercise, BFR was applied periodically three times per leg with a pressure of 40% of the individual-limb-occlusion-pressure. Measurement time points were six- (baseline), 3-weeks and 5-days before the surgery (Pre-OP), as well as three- and 6-months postoperatively. Outcome measures were muscular strength of the thigh muscles, thigh circumference as well as QoL and functional activity, examined by 6-min walking- and chair rising test.

Results: Both training groups indicated significantly improved leg muscle strength following the prehabilitation period with a superior effect for the BFR-group (BFR: ∼170% vs. AC: ∼91%, p < 0.05). No significant changes in leg strength occurred in the CON (∼3%, p = 0.100). Further, patients in BFR-group indicated significantly improved skeletal muscle mass assessed by femoral circumference following prehabilitation period (∼7%, p < 0.05), while no significant changes occurred in the CON (−1.14%, p = 0.131) and AC-group (∼3%, p = 0.078). At 3-months Post-OP, the CON and BFR-group revealed a significant decrease in femoral circumference compared to the Pre-OP (CON: ∼3%, BFR: ∼4%; p < 0.05), but BFR-group remained above the baseline level (∼3%, p < 0.05). No significant change in femoral circumference was found for AC-group (∼2%, p = 0.078). In addition, the prehabilitation with BFR provided notably improved Knee Injury and Osteoarthritis Outcome Scores (KOOS) especially in pain perception with significant higher effect compared to other groups (CON: −2%, AC: 13%, BFR: 41%; p < 0.05). In long-term rehabilitation after 6-months, all groups showed significantly improved KOOS scores in all dimensions (CON: ∼110%, AC: ∼132%, BFR: ∼225%; p < 0.01), and functional examinations (CON: ∼26%, AC: ∼16%, BFR: ∼53%; p < 0.01).

Conclusion: The present findings show that BFR-prehabilitation induce significant improvements in muscle function and QoL before TKA surgery. In addition, the supporting effect of prehabilitation on postoperative regeneration and QoL should be highlighted, illustrating prolonged beneficial effects of BFR on muscular and functional performance in a “better in, better out”-manner.

Acute myeloid leukemia-induced functional inhibition of healthy CD34+ hematopoietic stem and progenitor cells

Acute myeloid leukemia (AML) is characterized by an expansion of leukemic cells and a simultaneous reduction of normal hematopoietic precursors in the bone marrow (BM) resulting in hematopoietic insufficiency, but the underlying mechanisms are poorly understood in humans. Assuming that leukemic cells functionally inhibit healthy CD34+ hematopoietic stem and progenitor cells (HSPC) via humoral factors, we exposed healthy BM-derived CD34+ HSPC to cell-free supernatants derived from AML cell lines as well as from 24 newly diagnosed AML patients. Exposure to AML-derived supernatants significantly inhibited proliferation, cell cycling, colony formation, and differentiation of healthy CD34+ HSPC. RNA sequencing of healthy CD34+ HSPC after exposure to leukemic conditions revealed a specific signature of genes related to proliferation, cell-cycle regulation, and differentiation, thereby reflecting their functional inhibition on a molecular level. Experiments with paired patient samples showed that these inhibitory effects are markedly related to the immunomagnetically enriched CD34+ leukemic cell population. Using PCR, ELISA, and RNA sequencing, we detected overexpression of TGFβ1 in leukemic cells on the transcriptional and protein level and, correspondingly, a molecular signature related to TGFβ1 signaling in healthy CD34+ HSPC. This inhibitory effect of TGFβ1 on healthy hematopoiesis was functionally corrobated and could be pharmacologically reverted by SD208, an inhibitor of TGFβ receptor 1 signaling. Overall, these data indicate that leukemic cells induce functional inhibition of healthy CD34+ HSPC, at least in part, through TGFβ1, suggesting that blockage of this pathway may improve hematopoiesis in AML.

Invasive Assessment of Hemodynamic, Metabolic and Ionic Consequences During Blood Flow Restriction Training

Purpose: Medically recommended training often faces the dilemma that necessary mechanical intensities for muscle adaptations exceed patients' physical capacity. In this regard, blood flow restriction (BFR) training is becoming increasingly popular because it enables gains in muscle mass and strength despite using low-mechanical loads combined with external venous occlusion. Since the underlying mechanisms are still unknown, we applied invasive measurements during exercise with and without BFR to promote physiological understanding and safety of this popular training technique.

Methods: In a randomized cross-over design, ten healthy men (28.1 ± 6.5 years) underwent two trials of unilateral biceps curls either with (BFR) and without BFR (CON). For analysis of changes in intravascular pressures, blood gases, oximetry and electrolytes, an arterial and a venous catheter were placed at the exercising arm before exercise. Arterial and venous blood gases and intravascular pressures were analyzed before, during and 5 min after exercise.

Results: Intravascular pressures in the arterial and venous system were more increased during exercise with BFR compared to CON (p < 0.001). Furthermore, arterial and venous blood gas analyses revealed a BFR-induced metabolic acidosis (p < 0.05) with increased lactate production (p < 0.05) and associated elevations in [K⁺], [Ca²⁺] and [Na⁺] (p < 0.001).

Conclusion: The present study describes for the first time the local physiological changes during BFR training. While BFR causes greater hypertension in the arterial and venous system of the exercising extremity, observed electrolyte shifts corroborate a local metabolic acidosis with concurrent rises in [K⁺] and [Na⁺]. Although BFR could be a promising new training concept for medical application, its execution is associated with comprehensive physiological challenges.

The learning curve of patient-specific unikondylar arthroplasty may be advantageous to off-the-shelf implants: A preliminary study

Introduction

Introducing a new arthroplasty system into clinical routine is challenging and could have an effect on early results. Since UKA are known to have failure mechanisms related to technical factors, reliable results and easy adoption are ideal. The question remains whether there are differences in objective procedure parameters in the early learning curve of different UKA systems.

Methods

two different UKA implants (Biomet Oxford[BO] followed by Conformis iuni[CI]) were introduced consecutively into clinical routine. We retrospectively analyzed the first 20 cases of each implant for one arthroplasty surgeon regarding operating time, correction of the mechanical axis, learning curve parameters, and revision rate of implants for 1.5 years postoperatively.

Results

Operating time (BO:98.3 ± 26.3min, CI:83.85 ± 21.8min (p < 0.078)), and tourniquet time differed in favor of the CI implant (BO:97.5 ± 29.5min; CI:73.5 ± 33.2 min; p < 0.017)). Mechanical alignment was restored in boths (preop:BO:mean 2.9°varus, CI:2.7°varus, postop:BOmean1.3°varus, CI:1°varus), while one BO patient and two CI patients were overcorrected. Operating time decreased from the first five implants to implants 16-20 for CI (95.2 ± 18.5min to 69 ± 21.5min, p < 0.076) and BO (130.6 ± 27.6min to 78 ± 17.3min, p < 0.009). Within 18 months of follow-up, 2 BO and 1 CI implants were revised.

Conclusion

The introduction of an UKA implant was associated with longer surgery in both implants. Procedure time seems to differ between implants, while a learning curve was observed regarding instrumentation. CI implants seem to be reliable and adaptable in a medium-volume practice. The early results of this retrospective single-surgeon study were in favor of the individualized implant. Certainly, further studies encompassing larger cohorts with various implants are needed.

Automatic Cartilage Segmentation for Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Hip Joint Cartilage: A Feasibility Study

OBJECTIVE

Automatic segmentation for biochemical cartilage evaluation holds promise for an efficient and reader-independent analysis. This pilot study aims to investigate the feasibility and to compare delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) hip joint assessment with manual segmentation of acetabular and femoral head cartilage and dGEMRIC hip joint assessment using automatic surface and volume processing software at 3 Tesla.

DESIGN

Three-dimensional (3D) dGEMRIC data sets of 6 patients with hip-related pathology were assessed (1) manually including multiplanar image reformatting and regions of interest (ROI) analysis and (2) automated by using a combined surface and volume processing software. For both techniques, T1_Gd values were obtained in acetabular and femoral head cartilage at 7 regions (anterior, anterior-superior, superior-anterior, superior, superior-posterior, posterior-superior, and posterior) in central and peripheral portions. Correlation between both techniques was calculated utilizing Spearman's rank correlation coefficient.

RESULTS

A high correlation between both techniques was observed for acetabular (ρ = 0.897; P < 0.001) and femoral head (ρ = 0.894; P < 0.001) cartilage in all analyzed regions of the hip joint (ρ between 0.755 and 0.955; P < 0.001).

CONCLUSIONS

Automatic cartilage segmentation with dGEMRIC assessment for hip joint cartilage evaluation seems feasible providing high to excellent correlation with manually performed ROI analysis. This technique is feasible for an objective, reader-independant and reliable assessment of biochemical cartilage status.

Influence of leg length inequalities on pelvis and spine in patients with total hip arthroplasty

Background

Leg length inequalities (LLIs) are a common finding in patients with a total hip arthroplasty (THA). Therefore, we compared the effects of simulated LLIs in patients with total hip arthroplasty (THA) with a matched control group.

Research question

Do LLIs lead to different effects on the musculoskeletal apparatus of patients with a THA then in a control group?

Methods

In 99 patients with a THA the effects of simulated LLIs were compared to a matched control group of 101 subjects without a hip arthroplasty. First, we compared methods for LLI quantification (tape measurements, pelvic x- ray and rasterstereography). Second, the effects of simulated LLIs on the spine and pelvis were evaluated in both groups using surface topography. LLIs of 5, 10, 15, 20 and 30 mm were simulated on both sides with a simulation platform. The changes of pelvic position (pelvic obliquity & pelvic torsion) and the effects on spinal posture (surface rotation & lateral deviation) were measured and analysed using a surface topography system.

Results

Mean LLI measured with a tape was 0.9 mm (SD +/- 14.8). Mean pelvic obliquity measured on x-rays was 1.2 mm (SD +/- 11.6) and with surface topography 0.9 mm (SD +/- 7.9). Simulated LLIs resulted in significant changes of pelvic position and spinal posture in the patient and control group. Interestingly, our study showed that simulated LLIs lead to greater changes in pelvic position (p<0.05) in patients with a THA.

Significance

This is the first study to demonstrate that LLIs might have a greater impact on the pelvic position of THA patients than in native hips, which could indicate that LLIs do need to be compensated differently in patients with THA than in patients without a THA.

Secretome analysis of human bone marrow derived mesenchymal stromal cells

As an essential cellular component of the bone marrow (BM) microenvironment mesenchymal stromal cells (MSC) play a pivotal role for the physiological regulation of hematopoiesis, in particular through the secretion of cytokines and chemokines. Mass spectrometry (MS) facilitates the identification and quantification of a large amount of secreted proteins (secretome), but can be hampered by the false-positive identification of contaminating proteins released from dead cells or derived from cell medium. To reduce the likelihood of contaminations we applied an approach combining secretome and proteome analysis to characterize the physiological secretome of BM derived human MSC. Our analysis revealed a secretome consisting of 315 proteins. Pathway analyses of these proteins revealed a high abundance of proteins related to cell growth and/or maintenance, signal transduction and cell communication thereby representing key biological functions of BM derived MSC on protein level. Within the MSC secretome we identified several cytokines and growth factors such as VEGFC, TGF-β1, TGF-β2 and GDF6 which are known to be involved in the physiological regulation of hematopoiesis. By comparing the peptide patterns of secretomes and cell lysates 17 proteins were identified as candidates for proteolytic processing. Taken together, our combined MS work-flow reduced the likelihood of contaminations and enabled us to carve out a specific overview about the composition of the secretome from human BM derived MSC. This methodological approach and the specific secretome signature of BM derived MSC may serve as basis for future comparative analyses of the interplay of MSC and HSPC in patients with hematological malignancies.

Biomechanical Stability and Osteogenesis in a Tibial Bone Defect Treated by Autologous Ovine Cord Blood Cells-A Pilot Study

The aim of this study was to elucidate the impact of autologous umbilical cord blood cells (USSC) on bone regeneration and biomechanical stability in an ovine tibial bone defect. Ovine USSC were harvested and characterized. After 12 months, full-size 2.0 cm mid-diaphyseal bone defects were created and stabilized by an external fixateur containing a rigidity measuring device. Defects were filled with (i) autologous USSC on hydroxyapatite (HA) scaffold (test group), (ii) HA scaffold without cells (HA group), or (iii) left empty (control group). Biomechanical measures, standardized X-rays, and systemic response controls were performed regularly. After six months, bone regeneration was evaluated histomorphometrically and labeled USSC were tracked. In all groups, the torsion distance decreased over time, and radiographies showed comparable bone regeneration. The area of newly formed bone was 82.5 ± 5.5% in the control compared to 59.2 ± 13.0% in the test and 48.6 ± 2.9% in the HA group. Labeled cells could be detected in lymph nodes, liver and pancreas without any signs of tumor formation. Although biomechanical stability was reached earliest in the test group with autologous USSC on HA scaffold, the density of newly formed bone was superior in the control group without any bovine HA.

[Degenerative changes in the hand and wrist in elite MMA fighting - an MRI study in comparison to boxing]

OBJECTIVE

Mixed martial arts (MMA) is a combination of multiple combat sports. Acute injuries in MMA are well known and have been broadly described. However, there is little knowledge about degenerative changes in the musculoskeletal system. The aim of this study was to investigate the impact of techniques used in MMA on the occurrence of degenerative changes in the hand and wrist in comparison to classical boxing.

METHODS

11 MMA fighters and 10 boxers with chronic wrist pain were clinically examined. Age, weight, years of training, number of fights, level of competition and weekly hours of training were recorded. To determine degenerative changes, an MRI of the symptomatic hand was assessed.

RESULTS

Years of training, level of competition and number of fights did not show a significant difference between MMA and boxing fighters (p > 0.05), but MMA fighters showed significantly more hours of training per week (p < 0.001). The MMA fighters had more often and more severe degenerative changes of all examined structures (bone, fibrocartilage, ligaments and tendons), with the category "bone" reaching significance (p = 0.002).

CONCLUSION

MMA athletes show significantly greater incidence and degree of degeneration in hand and wrist joints. The exact reasons are still unknown and further research is needed to determine the influence of MMA techniques on the severity of degenerative changes in the hand and wrist.

The role of oxidative and nitrosative stress in the pathology of osteoarthritis: Novel candidate biomarkers for quantification of degenerative changes in the knee joint

Osteoarthritis (OA) is the most frequently diagnosed joint disorder worldwide with increasing prevalence and crucial impact on the quality of life of affected patients through chronic pain, decreasing mobility and invalidity. Although some risk factors, such as age, obesity and previous joint injury are well established, the exact pathogenesis of OA on a cellular and molecular level remains less understood. Today, the role of nitrosative and oxidative stress has not been investigated conclusively in the pathogenesis of OA yet. Therefore, the objective of this study was to identify biological substances for oxidative and nitrosative stress, which mirror the degenerative processes in an osteoarthritic joint. 69 patients suffering from a diagnosed knee pain participated in this study. Based on the orthopedic diagnosis, patients were classified into an osteoarthritis group (OAG, n=24) or in one of two control groups (meniscopathy, CG1, n=11; anterior cruciate ligament rupture, CG2, n=34). Independently from the study protocol, all patients underwent an invasive surgical intervention which was used to collect samples from the synovial membrane, synovial fluid and human serum. Synovial biopsies were analyzed histopathologically for synovitis (Krenn-Score) and immunohistochemically for detection of end products of oxidative (8-isoprostane F2α) and nitrosative (3-nitrotyrosine) stress. Additionally, the fluid samples were analyzed for 8-isoprostane F2α and 3-nitrotyrosine by competitive ELISA method. The analyzation of inflammation in synovial biopsies revealed a slight synovitis in all three investigated groups. Detectable concentrations of 3-nitrotyrosine were reported in all three investigated groups without showing any significant differences between the synovial biopsies, fluid or human serum. In contrast, significant increased concentrations of 8-isoprostane F2α were detected in OAG compared to both control groups. Furthermore, our data showed a significant correlation between the histopathological synovitis and oxidative stress in OAG (r=0.728, P<0.01). There were no significant differences between the concentrations of 8-isoprostane F2α in synovial fluid and human serum. The findings of the current study support the hypothesis that oxidative and nitrosative stress are components of the multi-factory pathophysiological formation of OA. It seems reasonable that an inflammatory process in the synovial membrane triggers the generation of oxidative and nitrosative acting substances which can lead to a further degradation of the articular cartilage. Based on correlations between the observed degree of inflammation and investigated biomarkers, especially 8-isoprostane F2α seems to be a novel candidate biomarker for OA. However, due to the finding that also both control groups showed increased concentrations of selected biomarkers, future studies have to validate the diagnostic potential of these biomarkers in OA and in related conditions of the knee joint.

Transforming growth factor β1-mediated functional inhibition of mesenchymal stromal cells in myelodysplastic syndromes and acute myeloid leukemia

Mesenchymal stromal cells are involved in the pathogenesis of myelodysplastic syndromes and acute myeloid leukemia, but the underlying mechanisms are incompletely understood. To further characterize the pathological phenotype we performed RNA sequencing of mesenchymal stromal cells from patients with myelodysplastic syndromes and acute myeloid leukemia and found a specific molecular signature of genes commonly deregulated in these disorders. Pathway analysis showed a strong enrichment of genes related to osteogenesis, senescence, inflammation and inhibitory cytokines, thereby reflecting the structural and functional deficits of mesenchymal stromal cells in myelodysplastic syndromes and acute myeloid leukemia on a molecular level. Further analysis identified transforming growth factor β1 as the most probable extrinsic trigger factor for this altered gene expression. Following exposure to transforming growth factor β1, healthy mesenchymal stromal cells developed functional deficits and adopted a phenotype reminiscent of that observed in patient-derived stromal cells. These suppressive effects of transforming growth factor β1 on stromal cell functionality were abrogated by SD-208, an established inhibitor of transforming growth factor β receptor signaling. Blockade of transforming growth factor β signaling by SD-208 also restored the osteogenic differentiation capacity of patient-derived stromal cells, thus confirming the role of transforming growth factor β1 in the bone marrow microenvironment of patients with myelodysplastic syndromes and acute myeloid leukemia. Our findings establish transforming growth factor β1 as a relevant trigger causing functional inhibition of mesenchymal stromal cells in myelodysplastic syndromes and acute myeloid leukemia and identify SD-208 as a candidate to revert these effects.

Partial Hemiresurfacing of Osteochondral Defects of the Talus? Surgical Technique and Preliminary Report from Four Patients

BACKGROUND

Osteochondral lesions of the medial talus (OLT) frequently lead to chronic ankle pain and osteoarthritis. Arthroscopic debridement, subchondral bone stimulation by drilling, and microfracturing are options for primary therapy in small lesions. In larger lesions, restoration of the talar dome contour seems to be a mandatory course of action.

METHODS

In a case series, we followed up four patients being treated with a focal resurfacing prosthetic due to large osteochondral talar lesions. In contrast to other studies, we can report on an off-label application to restore defects of the lateral talar dome with two patients for the first time. At follow-up, three patients reported a remarkable reduction in pain and were able to return to sports activities. One patient developed pseudarthrosis of the medial malleolar osteosynthesis.

CONCLUSIONS

With selected patients, focal resurfacing appears to be an option for large osteochondral defects of the talus.

T2*-Mapping of Acetabular Cartilage in Patients With Femoroacetabular Impingement at 3 Tesla: Comparative Analysis with Arthroscopic Findings

Objective To evaluate the diagnostic accuracy of T2*-mapping for detecting acetabular cartilage damage in patients with symptomatic femoroacetabular impingement (FAI). Design A total of 29 patients (17 females, 12 males, mean age 35.6 ± 12.8 years, mean body mass index 25.1 ± 4.1 kg/m², 16 right hips) with symptomatic FAI underwent T2* MRI and subsequent hip arthroscopy. T2* values were obtained by region of interest analysis in seven radially reformatted planes around the femoral neck (anterior, anterior-superior, superior-anterior, superior, superior-posterior, posterior-superior, posterior). Intraoperatively, a modified Outerbridge classification was used for assessment of the cartilage status in each region. T2* values and intraoperative data were compared, and sensitivity, specificity, negative predictive values (NPV) and positive predictive values (PPV) as well as the correlation between T2*-mapping and intraoperative findings, were determined. The mean time interval between MRI and arthroscopy was 65.7 ± 48.0 days. Results Significantly higher T2* values were noted in arthroscopically normal evaluated cartilage than in regions with cartilage degeneration (mean T2* 25.6 ± 4.7 ms vs. 19.9 ± 4.5 ms; P < 0.001). With the intraoperative findings as a reference, sensitivity, specificity, NPV and PPV were 83.5%, 67.7%, 78.4% and 74.4%, respectively. The correlation between T2*-mapping and intraoperative cartilage status was moderate (ρ = -0.557; P < 0.001). Conclusions T2*-mapping enabled analysis of acetabular cartilage with appropriate correlation with intraoperative findings and promising results for sensitivity, specificity, PPV, and NPV in this cohort. Our results emphasize the value of T2*-mapping for the diagnosis of hip joint cartilage pathologies in symptomatic FAI.

Ischemic Preconditioning Blunts Muscle Damage Responses Induced by Eccentric Exercise

PURPOSE

Ischemic preconditioning (IPC) is known to reduce muscle damage induced by ischemia and reperfusion injury during surgery. Because of similarities between the pathophysiological formation of ischemia and reperfusion injury and eccentric exercise-induced muscle damage (EIMD), as characterized by an intracellular accumulation of Ca, an increased production of reactive oxygen species, and increased proinflammatory signaling, the purpose of the present study was to investigate whether IPC performed before eccentric exercise may also protect against EIMD.

METHODS

Nineteen healthy men were matched to an eccentric-only (ECC; n = 9) or eccentric proceeded by IPC group (IPC + ECC; n = 10). The exercise protocol consisted of bilateral biceps curls (3 × 10 repetitions at 80% of the concentric one-repetition maximum). In IPC + ECC, IPC was applied bilaterally at the upper arms by a tourniquet (200 mm Hg) immediately before the exercise (3 × 5 min of occlusion, separated by 5 min of reperfusion). Creatine kinase (CK), arm circumference, subjective pain (visual analog scale score), and radial displacement (tensiomyography, maximal radial displacement) were assessed before IPC, preexercise, postexercise, and 20 min, 2 h, 24 h, 48 h, and 72 h postexercise.

RESULTS

CK differed from baseline only in ECC at 48 h (P < 0.001) and 72 h (P < 0.001) postexercise. After 24, 48, and 72 h, CK was increased in ECC compared with IPC + ECC (between groups: 24 h, P = 0.004; 48 h, P < 0.001; 72 h, P < 0.001). The visual analog scale score was significantly higher in ECC at 24-72 h postexercise when compared with IPC + ECC (between groups: all P values < 0.001). The maximal radial displacement was decreased on all postexercise days in ECC (all P values < 0.001) but remained statistically unchanged in IPC + ECC (between groups: P < 0.01).

CONCLUSIONS

These findings indicate that IPC performed before a bout of eccentric exercise of the elbow flexors blunts EIMD and exercise-induced pain while maintaining the contractile properties of the muscle.

T2* Mapping of the Hip in Asymptomatic Volunteers with Normal Cartilage Morphology: An Analysis of Regional and Age-Dependent Distribution

Objective To assess age-dependent and regional differences in T2* relaxation measurements in hip joint cartilage of asymptomatic volunteers at 3 T. Design Three age cohorts (cohort 1: age 20-30 years, 15 individuals; cohort 2: age 30-40 years, 17 individuals; cohort 3: age 40-50 years, 15 individuals) were enrolled. T2* values were obtained in the central and peripheral cartilage of the acetabulum and the femoral head in 7 regions (anterior to superior and posterior). Results T2* did not differ among age cohorts in acetabular cartilage (cohort 1: 24.65 ± 6.56 ms, cohort 2: 24.70 ± 4.83 ms, cohort 3: 25.81 ± 5.10 ms, P = 0.10) and femoral head cartilage (cohort 1: 27.08 ± 8.24 ms, cohort 2: 25.90 ± 7.82 ms, cohort 3: 26.50 ± 5.61 ms, P = 0.34). Analysis of the regional T2* distribution pattern indicates increased T2* values in the anterior, anterior-superior, superior-anterior, and the posterior-superior aspects of acetabular and femoral head cartilage. For acetabular cartilage, higher values were observed in the central region (25.90 ± 4.80 ms vs. 24.21 ± 4.05 ms, P < 0.0001) whereas femoral head cartilage did not reveal such differences (26.62 ± 5.74 ms vs. 26.37 ± 5.89 ms, P = 0.44). Conclusions The T2* analysis of presumably healthy hip joint cartilage does not seem to be stratified according to age in this population. Regional T2* variation throughout hip joint cartilage is apparent in this modality.

Blood flow restriction training as a prehabilitation concept in total knee arthroplasty: A narrative review about current preoperative interventions and the potential impact of BFR

Osteoarthritis of the knee is one of the most commonly diagnosed joint ailments and responsible for increased rates of total knee arthroplasty surgeries worldwide. Whereas the surgical approach is able to diminish the perceived knee pain of concerned patients', the postoperative recovery is often accompanied by persistent skeletal muscle dysfunctions and atrophy, which is responsible for functional deficits for up to several years. Recent findings indicate that surgery induced adverse effects on skeletal muscles are largely associated with the use of pneumatic tourniquets, wherefore several studies try to reduce tourniquet use in orthopedic surgery. However, due to comparable incidence of muscle impairment and increased surgical challenge, the most frequently applied surgical technique in TKA is still associated with the use of tourniquets. When attenuating TKA induced adverse effects, the preoperative preparation of patients by specific exercises (called prehabilitation) was able to enhance preoperative overall fitness through associated accelerated recovery. Based on patients' limited functional activity, prehabilitation techniques have to be particularly designed to allow regular adherence. The present paper is based on a narrative review of current literature, and provides a novel hypothesis by which blood flow restriction exercises (BFR) are able to improve patients' compliance to prehabilitation. BFR training is characterized by the application of low-resistance exercise with similar intensities as daily living tasks in association with a suppression of venous blood flow in an extremity, achieving significant morphological and neuromuscular adaptations in skeletal muscles. In addition, preoperative enhancements in muscle health with corresponding benefits in overall fitness, BFR induced molecular alterations could also be able to interfere with TKA induced pathological signaling. Therefore, based on the known major impact of BFR on skeletal muscle physiology, the present paper aims to illustrate the potential beneficial impact of BFR training as a prehabilitation concept to promote patients regular adherence to preoperative exercises and thus achieve an accelerated recovery and increases in patients' satisfaction.

Gait deviations in transverse plane after SCFE in dependence on the femoral offset

Residual deformity of the femoral head after slipped capital femoral epiphysis (SCFE) may be accompanied by a loss of femoral offset and lead to femoro-acetabular impingement (FAI), especially during hip flexion. It is hypothesized that during phases of the gait cycle, when the hip is flexed, the offset-loss is compensated by an increased external rotation. The gait pattern of 36 patients suffering from SCFE, who were treated by pinning-in-situ, were compared to a control group of 40 healthy adults by an instrumented 3D-gait analysis. Total patient group was subdivided into 3 subgroups in dependence on the offset (offset groups (OG)) quantified by the angle α according to Nötzli: OG1: α-angle <55°, OG2: α-angle between 55 and 75°, OG3: α-angle >75°. Comparisons were made at 3 instants: initial foot contact (0% gait cycle (GC)), 40-60% GC and 90-100% GC. Patients showed an increased external hip rotation during all 3 periods of the GC with a tendency of increasing external rotation in association with offset-loss. Only during hip extension (40-60% GC) there was a weak correlation between angle α and hip rotation (r=-0.375, p=0.024). In conclusion, the offset-loss does not lead to a functional relevant impingement during walking which needs compensation strategies like increasing external rotation during periods of hip flexion.

T2* Mapping for Hip Joint Cartilage Assessment: Pre-MRI Exercise and Time of Imaging Do Not Bias the T2* Measurement in Asymptomatic Volunteers

Objective To identify if the time of day and pre-imaging exercise matter while performing T2* mapping of hip joint cartilage at 3 T. Design Nine asymptomatic healthy volunteers (mean age 27.4 ± 4.0 years) with no obvious morphological evidence of cartilage damage were enrolled. The MRI protocol included a double-echo steady state (DESS) sequence for morphological cartilage assessment and a multi-echo data image combination sequence for the T2* measurement. T2* values were obtained between 8 and 11 a.m., between 3 and 6 p.m., and after 50 knee-bends at several time points of each measurement (0, 15, 30, 45, 60 minutes). Results We observed no differences ( P = 0.47) between the T2* values obtained in the morning (T2* = 22.9 ± 3.0 ms) and those measured in the afternoon (T2* = 23.2 ± 3.2 ms). We also observed no statistically significant differences between the T2* values at different time points ( P = 0.67) or after 50 knee-bends ( P = 0.43). Conclusions Timing of the scan and pre-imaging exercise clearly did not matter in this modality. This study consolidates the value of T2* imaging in hip joint cartilage that seems to be independent of diurnal effects and physical activity prior to MRI.

Thickness Distribution of Glenohumeral Joint Cartilage

High-resolution 3-dimensional cartilage-specific magnetic resonance imaging (MRI) was performed at 3 T to test the following hypotheses: (1) there is a nonuniform cartilage thickness distribution both on the proximal humerus and on the glenoid surface and (2) the glenohumeral joint as a combined system is congruent with the level of the joint cartilage surface without substantial radial mismatch. Inclusion of 38 volunteers (19 females, mean age 24.34 ± 2.22 years; range 21-29 years) in a prospective study. Measurements of: cartilage thickness in 3 regions and 3 zones; radius of both circles (glenoid and humeral cartilage) for congruency calculation using 3-T MRI with 3-dimensional dual-echo steady-state sequence with water excitation. A homogenous mean cartilage thickness (1.2-1.5 mm) and slightly higher values for the glenoidal articulating surface radii both in the mid-paracoronar section (2.4 vs. 2.1 cm, P < 0.001) and in the mid-paraaxial section (2.4 vs. 2.1 cm, P < 0.001) compared with the humeral side were observed. The concept of a radial mismatch between the humeral head and the glenoid in healthy human subjects can be confirmed. This study provides normative data for the comparison of joint cartilage changes at the shoulder for future studies.

Imaging modalities in patients with slipped capital femoral epiphysis

BACKGROUND

Slipped capital femoral epiphysis (SCFE) is a frequent disorder of the adolescent hip, which may lead to avascular necrosis (AVN) of the femoral head, chondrolysis and early osteoarthritis due to the post-slip deformity of the proximal femur. To warrant the best possible outcome for the affected (and contralateral) hip, early diagnosis and proper treatment are needed.

METHODS

A review of the literature was undertaken to identify today's role of available imaging modalities in the management of SCFE.

SUMMARY

This review outlines the relevancy of different imaging modalities such as radiography, ultrasound, CT, MRI and bone scintigraphy in the treatment of SCFE patients. While standard radiography is the first-choice imaging modality for patients with suspected SCFE, ultrasound and advanced imaging modalities may aid in surgical planning, diagnosis of complications such as AVN and treatment follow-up.

Bone Marrow Aspirate Concentrate in Combination With Intravenous Iloprost Increases Bone Healing in Patients With Avascular Necrosis of the Femoral Head: A Matched Pair Analysis

With disease progression, avascular necrosis (AVN) of the femoral head may lead to a collapse of the articular surface. The exact pathophysiology of AVN remains unclear, although several conditions are known that can result in spontaneous cell death, leading to a reduction of trabecular bone and the development of AVN. Hip AVN treatment is stage-dependent in which two main stages of the disease can be distinguished: pre-collapse (ARCO 0-II) and post-collapse stage (ARCO III-IV, crescent sign). In the pre-collapse phase, core decompression (CD), with or without the addition of bone marrow (e.g. bone marrow aspirate concentrate, BMAC) or bone graft, is a common treatment alternative. In the post-collapse phase, THA (total hip arthroplasty) must be performed in most of the patients. In addition to surgical treatment, the intravenous application of Iloprost has been shown to have a curative potential and analgesic effect. From October 2009 to October 2014, 49 patients with AVN (stages I-III) were treated with core decompression at our institution. All patients were divided into group A (CD + BMAC) and group B (CD alone). Of these patients, 20 were included in a matched pair analysis. The patients were matched to age, gender, ARCO-stage, Kerboul combined necrotic angle, the cause of AVN, and whether Iloprost-therapy was performed. The Merle d’Aubigné Score and the Kerboul combined necrotic angle in a-p and lateral radiographs were evaluated pre- and postoperatively. The primary endpoint was a total hip arthroplasty. In group A, two patients needed THA while in group B four patients were treated with THA. In group A, the Merle d’Aubigné Score improved from 13.5 (pre-operatively) to 15.3 (postoperatively). In group B there was no difference between the pre- (14.3) and postoperative (14.1) assessment. The mean of the Kerboul angle showed no difference in both groups compared pre- to postoperatively (group A: pre-op 212°, postop 220°, group B: pre-op 213, postop 222°). Regarding radiographic evaluation, the interobserver variability revealed a moderate agreement between two raters regarding the pre-(ICC 0.594) and postoperative analysis (ICC 0.604).This study demonstrates that CD in combination with the application of autologous bone marrow aspirate concentrate into the femoral head seems to be a safe and efficient treatment alternative in the early stages of AVN of the femoral head when compared to CD alone.

Glycosaminoglycan chemical exchange saturation transfer at 3T MRI in asymptomatic knee joints

BACKGROUND

Biochemical alterations such as glycosaminoglycan (GAG) depletion occur early in the course of osteoarthritis, but cannot be detected with standard magnetic resonance techniques. With glycosaminoglycan chemical exchange saturation transfer (gagCEST), a biochemical imaging technique, it is feasible to detect biochemical components in knee joint cartilage.

PURPOSE

To establish baseline values for gagCEST magnetic resonance imaging (MRI) in knee joint cartilage at 3 Tesla (T).

MATERIAL AND METHODS

Twenty volunteers (8 women, 12 men; mean age, 24.55 ± 2.35 years;age range, 21-29 years) with no history or clinical findings indicative of knee joint pathologies underwent MRI at 3T. The imaging protocol included three-dimensional (3D) double-echo steady-state sequence for morphological cartilage assessment and a prototype 3D CEST pulse sequence to evaluate the CEST effects in six cartilage regions of the knee joint: (i) lateral femoral condyle; (ii) medial femoral condyle; (iii) lateral tibial plateau; (iv) medial tibial plateau; (v) patella; and (vi) trochlea. We used the asymmetry of the magnetization transfer ratio (MTRasym) parameter to quantify the gagCEST effects in these regions.

RESULTS

Regional differences revealed high MTRasym values in the patellar (1.62% ± 1.19%) and the trochlear (1.17% ± 1.29%) cartilages, and low MTRasym values in the medial femoral condyle (0.41% ± 0.58%) and the lateral tibial plateau (0.52% ± 0.53%) cartilages.

CONCLUSION

Regional differences in the gagCEST values must be considered when conducting gagCEST imaging of knee joint cartilage. In the future gagCEST imaging may be an additional feature in the evaluation of the biochemical composition of knee joint cartilage.

Interprofessional education as part of becoming a doctor or physiotherapist in a competency-based curriculum

INTRODUCTION

Interprofessional learning is a critical pre-requisite for future interprofessional work. Structural adaptations in education offer possibilities to introduce new concepts. Rheumatic and musculoskeletal diseases (RMD) are both prevented and treated by physicians and physiotherapists but the development of interprofessional roles is seldom part of curricula.

PROJECT DESCRIPTION

A complex, longitudinal interprofessional educational approach for future doctors and physiotherapists was designed and implanted at various stages (anatomy, physical examination, pathology, therapy). Most segments of the RMD curriculum are now based on interprofessional classes. Student satisfaction with learning is continually and comparatively evaluated. Learning success is assessed with practical and written exams.

RESULTS

Interprofessional teaching was first introduced in 2013 for 420 first-year and 360 fourth-year medical students, along with 40 first- and third-year physiotherapy majors. The satisfaction with teaching and learning is high and distinctly above average for all teaching areas (satisfaction RMD rated as 2.4; average for all is 3.3). The percentage of those who pass the final exam is 94%. 100% of the students surveyed support the continuation of this interprofessional unit.

CONCLUSION

Interprofessional teaching of RMD can be successfully implemented for future physicians and physiotherapists at different learning levels.

T2* mapping of ovine intervertebral discs: Normative data for cervical and lumbar spine

To obtain T2* values in histologically evaluated healthy ovine intervertebral discs of the cervical and lumbar spine. Intervertebral discs of nine sheep and nine lambs underwent histological assessment with the modified Boos score for grading of disc degeneration. Discs with a score <10 points (maximum = 40 points) underwent T2* mapping (n = 64). Mid-sagittal T2* values were obtained in five regions: Anterior annulus fibrosus, anterior nucleus pulposus, central nucleus pulposus, posterior nucleus pulposus, and posterior annulus fibrosus. We noted a zonal T2* distribution with high values in the central nucleus and low T2* values in the anterior and posterior annulus fibrosus. The T2* values were higher in lamb than in sheep IVDs for both cervical and lumbar spine (p < 0.001). The T2* values were also higher in the cervical than in the lumbar spine (p = 0.029 for sheep and p < 0.001 for lamb IVDs). The T2* values obtained in these ovine intervertebral discs can serve as baseline values for future T2* measurements both in health and disease.

Long-term Clinical Results after Iloprost Treatment for Bone Marrow Edema and Avascular Necrosis

The treatments of avascular osteonecrosis (AVN) include both conservative and surgical methods which are dependent on the stage and progression of the disease. The vasoactive-prostaglandin-analogue iloprost (PGI2) has been utilized in several areas of medicine and recently has been used for the treatment of AVN. A total of 108 patients with 136 osteonecrosis of different joints, etiology and severity were treated with iloprost. The mean follow-up was 49.71 months: range 15-96 months, and outcome measurements recorded regarding subjective complaints, visual analog scale (pain), function and survival. The outcome scores used include the Harris Hip Score, Knee Society score, Foot and Ankle Survey, visual analogue scale (VAS) and a separate questionnaire. The location and etiology of AVN in our study demonstrated the typical pattern. All of the observed side effects of the therapy were minor and completely reversible. Most of patients (74.8%) showed a significant improvement of subjective complaints and decrease in VAS pain scores after the treatment with iloprost. However, 20% of the treated joints with the stadium Association for Research on Osseous Circulation (ARCO) grade 2, 71% with ARCO 3 and 100% with ARCO 4 underwent subsequent total joint replacement. The medical treatment of bone marrow edema or avascular osteonecrosis by Iloprost provides an safe and effective alternative strategy in the management of AVN presenting in the early stages (ARCO 1 or 2). For more advanced stages (ARCO 3 or 4), surgical intervention should be prioritized.

Evaluation of Muscle Damage Marker after Mixed Martial Arts Matches

The aim of this paper is to identify predictors of serum muscle damage marker (MDM) response following mixed martial arts (MMA) matches. Creatine kinase activity (CK) and myoglobin concentration (Mb) were measured in ten male elite MMA fighters (aged 28±5.7 years) prior to, 2 h, 24 h, and 96 h following 9 different MMA matches. The number of performed upright punches and kicks (UKF) that failed the opponent, the number of obtained hits to the upper and lower body (LBH), as well as the total fight duration (TFD) were evaluated as potential predictors from video recordings. CK peaked 24 h (829±753 U/L(-1)) and Mb peaked 2 h (210±122 µg/L(-1)) post matches. Almost 80% of the peak CK variance could be explained by LBH and UKF, whereas 87% of the Mb variation was explained by TFD and LBH. MMA result in a significant skeletal muscle damage, which largely depends on LBH. Furthermore, eccentric contractions to decelerate kicks that missed the opponent and the TFD seem to contribute to the MDM response.

Enoxaparin and rivaroxaban have different effects on human mesenchymal stromal cells in the early stages of bone healing

Objectives

Venous thromboembolism (VTE) is a major potential complication following orthopaedic surgery. Subcutaneously administered enoxaparin has been used as the benchmark to reduce the incidence of VTE. However, concerns have been raised regarding the long-term administration of enoxaparin and its possible negative effects on bone healing and bone density with an increase of the risk of osteoporotic fractures. New oral anticoagulants such as rivaroxaban have recently been introduced, however, there is a lack of information regarding how these drugs affect bone metabolism and post-operative bone healing.

Methods

We measured the migration and proliferation capacity of mesenchymal stem cells (MSCs) under enoxaparin or rivaroxaban treatment for three consecutive weeks, and evaluated effects on MSC mRNA expression of markers for stress and osteogenic differentiation.

Results

We demonstrate that enoxaparin, but not rivaroxaban, increases the migration potential of MSCs and increases their cell count in line with elevated mRNA expression of C-X-C chemokine receptor type 4 (CXCR4), tumor necrosis factor alpha (TNFα), and alpha-B-crystallin (CryaB). However, a decrease in early osteogenic markers (insulin-like growth factors 1 and 2 (IGF1, IGF2), bone morphogenetic protein2 (BMP2)) indicated inhibitory effects on MSC differentiation into osteoblasts caused by enoxaparin, but not by rivaroxaban.

Conclusions

Our findings may explain the adverse effects of enoxaparin treatment on bone healing. Rivaroxaban has no significant impact on MSC metabolism or capacity for osteogenic differentiation in vitro.

Cite this article: Dr H. Pilge. Enoxaparin and rivaroxaban have different effects on human mesenchymal stromal cells in the early stages of bone healing. Bone Joint Res 2016;5:95–100. DOI: 10.1302/2046-3758.53.2000595.

Effects of thromboprophylaxis on mesenchymal stromal cells during osteogenic differentiation: an in-vitro study comparing enoxaparin with rivaroxaban

Background

Low-molecular-weight heparins (e.g. Enoxaparin) are widely used to prevent venous thromboembolism after orthopaedic surgery, but there are reports about serious side effects including reduction in bone density and strength. In recent years new oral antithrombotic drugs (e.g. direct Factor Xa-inhibitor, Rivaroxaban) have been used to prevent venous thromboembolism. However, there is lack of information on the effects of these new drugs on human mesenchymal stromal cells during osteogenic differentiation and, therefore, effects during postoperative bone healing.

Methods

We evaluated the effects of Rivaroxaban and Enoxaparin on the proliferation, mRNA and surface receptor expression as well as differentiation capacity of primary human mesenchymal stromal cells during their osteogenic differentiation.

Results

Enoxaparin, but not Rivaroxaban treatment significantly increased human mesenchymal stromal cell (hMSC) proliferation during the first week of osteogenic differentiation while suppressing osteogenic marker genes, surface receptor expression and calcification.

Conclusions

This is the first paper to demonstrate that Rivaroxaban had no significant influence on hMSC differentiation towards the osteogenic lineage, indicating a less affected bone healing process compared with Enoxaparin in vitro. Based on these findings Rivaroxaban seems to be superior to Enoxaparin in early stages of bone healing in vitro.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-0966-2) contains supplementary material, which is available to authorized users.

T2* mapping and delayed gadolinium-enhanced magnetic resonance imaging in cartilage (dGEMRIC) of humeral articular cartilage--a histologically controlled study

BACKGROUND

Cartilage biochemical imaging modalities that include the magnetic resonance imaging (MRI) techniques of T2* mapping (sensitive to water content and collagen fiber network) and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC, sensitive to the glycosaminoglycan content) can be effective instruments for early diagnosis and reliable follow-up of cartilage damage. The purpose of this study was to provide T2* mapping and dGEMRIC values in various histologic grades of cartilage degeneration in humeral articular cartilage.

METHODS

A histologically controlled in vitro study was conducted that included human humeral head cartilage specimens with various histologic grades of cartilage degeneration. High-resolution, 3-dimensional (3D) T2* mapping and dGEMRIC were performed that enabled the correlation of MRI and histology data. Cartilage degeneration was graded according to the Mankin score, which evaluates surface morphology, cellularity, toluidine blue staining, and tidemark integrity. SPSS software was used for statistical analyses.

RESULTS

Both MRI mapping values decreased significantly (P < .001) with increasing cartilage degeneration. Spearman rank analysis revealed a significant correlation (correlation coefficients ranging from -0.315 to 0.784; P < .001) between the various histologic parameters and the T2* and T1Gd mapping values.

CONCLUSION

This study demonstrates the feasibility of 3D T2* and dGEMRIC to identify various histologic grades of cartilage damage of humeral articular cartilage. With regard to the advantages of these mapping techniques with high image resolution and the ability to accomplish a 3D biochemically sensitive imaging, we consider that these imaging techniques can make a positive contribution to the currently evolving science and practice of cartilage biochemical imaging.

Opioids as an alternative to amide-type local anaesthetics for intra-articular application

PURPOSE

Recently, the safety profile of local anaesthetics in intra-articular use became into focus of investigation. Opioid drugs have a different mode of action and may be a safe and potent alternative for intra-articular application. The purpose of this in vitro study is to provide evidence for significant chondrotoxicity of amide-type local anaesthetics even after short-term application on human chondrocytes and to demonstrate the absence of such negative effects for opioids [morphine, morphine-6-glucuronide (M6G)].

METHOD

Visually intact cartilage explants of human, mainly osteoarthritic joints (n = 9), were harvested and cultivated in monolayer for expansion and transferred into alginate bead. The beads were incubated for increasing incubation times (15 min, 1 and 4 h) in decreasing concentrations (full, ½, ¼ for 15 min) of bupivacaine, ropivacaine, morphine, M6G or saline control. Adenosine triphosphate content of 798 beads was measured 3 days post-incubation to assess cell viability.

RESULTS

A clear ranking of cytotoxic potency: bupivacaine > ropivacaine > morphine = M6G = saline was observed. Results reveal a dose- and time-dependent manner of cytotoxic effects on human chondrocytes for bupivacaine and ropivacaine but not for opioids. Cell viability after exposure to morphine and M6G was comparable to exposure to saline.

CONCLUSION

The results confirm dose- and time-dependent cytotoxic effects on human chondrocytes for amide-type local anaesthetics. This study confirms the safety of morphine and M6G in terms of an absence of cytotoxic effects after intra-articular application, making them safe potential alternatives in clinical practice.

Advanced Imaging in Femoroacetabular Impingement: Current State and Future Prospects

Symptomatic femoroacetabular impingement (FAI) is now a known precursor of early osteoarthritis (OA) of the hip. In terms of clinical intervention, the decision between joint preservation and joint replacement hinges on the severity of articular cartilage degeneration. The exact threshold during the course of disease progression when the cartilage damage is irreparable remains elusive. The intention behind radiographic imaging is to accurately identify the morphology of osseous structural abnormalities and to accurately characterize the chondrolabral damage as much as possible. However, both plain radiographs and computed tomography (CT) are insensitive for articular cartilage anatomy and pathology. Advanced magnetic resonance imaging (MRI) techniques include magnetic resonance arthrography and biochemically sensitive techniques of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T1rho (T1ρ), T2/T2* mapping, and several others. The diagnostic performance of these techniques to evaluate cartilage degeneration could improve the ability to predict an individual patient-specific outcome with non-surgical and surgical care. This review discusses the facts and current applications of biochemical MRI for hip joint cartilage assessment covering the roles of dGEMRIC, T2/T2*, and T1ρ mapping. The basics of each technique and their specific role in FAI assessment are outlined. Current limitations and potential pitfalls as well as future directions of biochemical imaging are also outlined.

Zonal T2* and T1Gd assessment of knee joint cartilage in various histological grades of cartilage degeneration: an observational in vitro study

OBJECTIVES

Accurate assessment of cartilage status is increasingly becoming important to clinicians for offering joint preservation surgeries versus joint replacements. The goal of this study was to evaluate the validity of three-dimensional (3D), gradient-echo (GRE)-based T2* and T1Gd mapping for the assessment of various histological severities of degeneration in knee joint cartilage with potential implications for clinical management.

METHODS

MRI and histological assessment were conducted in 36 ex vivo lateral femoral condyle specimens. The MRI protocol included a 3D GRE multiecho data image combination sequence in order to assess the T2* decay, a 3D double-echo steady-state sequence for assessment of cartilage morphology, and a dual flip angle 3D GRE sequence with volumetric interpolated breathhold examination for the T1Gd assessment. The histological sample analysis was performed according to the Mankin system. The data were then analysed statistically and correlated.

RESULTS

We observed a significant decrease in the T2* and T1Gd values with increasing grades of cartilage degeneration (p<0.001) and a moderate correlation between T2* (r=0.514)/T1Gd (r=0.556) and the histological grading of cartilage degeneration (p<0.001). In addition, we noted a zonal variation in the T2* and T1Gd values reflecting characteristic zonal differences in the biochemical composition of hyaline cartilage.

CONCLUSIONS

This study outlines the potential of GRE-based T2* and T1Gd mapping to identify various grades of cartilage damage. Early changes in specific zones may assist clinicians in identifying methods of early intervention involving the targeted joint preservation approach versus moving forward with unicompartmental, bicompartmental or tricompartmental joint replacement procedures.

TRIAL REGISTRATION NUMBER

DRKS00000729.

Post-operative quality of life in children with severe perthes disease: differences to matched controls and correlation with clinical function

The diagnosis of Legg-Calvé-Perthes disease (LCPD) has a considerable influence on the daily life of the patients with restrictions in their leisure time activities. This might influence their mood. Until now this aspect of the disease has been neglected. Therefore the objective of the study was to evaluate the health related quality of life (HRQoL) of children with severe LCPD who had an extensive surgery with pelvic/femoral osteotomy. The KIDSCREEN-10 and the modified Modified Harris Hip Score (mHHS) -questionnaire were administered to 17 children (16 boys and 1 girl) aged 5 to 11 years at the time of surgery. Analyses of mHHS were made preoperatively and at the time of the follow-up examination at least 2 years postoperatively. KIDSCREEN-analyses were made postoperatively. The follow-up results were compared to an age-matched normal control group. Correlations were computed between KIDSCREEN-10 and mHHS pre- and post-operatively. The postoperative calculated KIDSCREEN-10-T-value [70.2 (SD 12.7)] was higher than the mean T-value of the control-group [56.6 (SD 10.4)]. The mHHS improved from 54.4 (SD 19.9) to a score of 99.5 (SD 1.5) postoperatively. A strong correlation was found between the preoperative mHHS and the postoperative KIDSCREEN-10-T-value (Spearman’s-rho 0.67, P=0.003). After containment improving surgery and a mean follow-up period of 4.2 years the HRQoL-status is even better compared with a healthy age-matched control group. As well an excellent clinical function could be achieved.

T2* mapping for articular cartilage assessment: principles, current applications, and future prospects

With advances in joint preservation surgery that are intended to alter the course of osteoarthritis by early intervention, accurate and reliable assessment of the cartilage status is critical. Biochemically sensitive MRI techniques can add robust biomarkers for disease onset and progression, and therefore, could be meaningful assessment tools for the diagnosis and follow-up of cartilage abnormalities. T2* mapping could be a good alternative because it would combine the benefits of biochemical cartilage evaluation with remarkable features including short imaging time and the ability of high-resolution three-dimensional cartilage evaluation-without the need for contrast media administration or special hardware. Several in vitro and in vivo studies, which have elaborated on the potential of cartilage T2* assessment in various cartilage disease patterns and grades of degeneration, have been reported. However, much remains to be understood and certain unresolved questions have become apparent with these studies that are crucial to the further application of this technique. This review summarizes the principles of the technique and current applications of T2* mapping for articular cartilage assessment. Limitations of recent studies are discussed and the potential implications for patient care are presented.

Comparison of hip joint cartilage degeneration assessed by histology and ex vivo optical coherence tomography

The aim of this study is to validate optical coherence tomography (OCT) in assessing human articular cartilage by means of histological analyses. Twenty resected human femoral head specimens were evaluated with OCT and histological analysis. OCT and histological evaluation was performed according to the Bear and the Mankin criteria. OCT grades and Mankin scores (total score and sub-score structure) were correlated and intra-/inter-observer agreement for repeated OCT evaluations was tested by interclass-correlation coefficient (ICC) analysis. OCT grades and Mankin scores were correlated [Spearman correlation=0.742 (total) and 0.656 (structure), P<0.001], revealing significant differences between the histological scores in various OCT grades of cartilage degeneration (P<0.001). Intra-observer (ICC 0.930) and inter-observer (ICC 0.933) reliability was high (P<0.001). OCT appears to be reliable in the assessment of human articular cartilage. Further studies on intra-operative cartilage evaluation by OCT are necessary to substantiate its applicability in clinical routine.

Radiological outcome and gait function of SCFE patients after growth arrest

PURPOSE

Slipped capital femoral epiphysis (SCFE) represents the most common disorder of the hip in adolescents and a preliminary stage of degenerative joint disease. Up to now, functional outcome evaluation measured by objective instruments has been commonly neglected. The present study investigates whether the pathoanatomy of the hip joint after SCFE-analyzed on a standard X-ray-match functional results gained by three-dimensional gait analysis. A variation of functional outcome depending on the radiological findings after growth arrest is hypothesized.

METHODS

Thirty-seven SCFE patients after growth arrest [mean age 18.5 years, standard deviation (SD) 4.61] with unilateral affection were included. The pathoanatomy of the hip joint was classified according to the radiological index of Heyman and Herndon and to aspherity. Three-dimensional gait analysis parameters were evaluated and subgroup analysis was performed according to the radiological results.

RESULTS

The radiological findings revealed very good results in general (average comprehensive index of Heyman and Herndon 94 ± 9 %, aspherity grade <2). Significant deviations of gait parameters in relation to the radiological result were an increase in step width, sagittal range of motion (ROM) of the pelvis and foot progression for the worse subgroup.

CONCLUSIONS

Taken as a whole, the pathoanatomy of the hip joint after SCFE matched the functional results gained by gait analysis. Functional outcome varied slightly depending on the radiological findings after growth arrest. Differences were most pronounced for foot progression. Only with the help of gait analysis was it possible to describe deviations more precisely and objectively. Further studies are required in order to show which alterations are relevant for the development of secondary osteoarthritis.

Can thrombin-activated platelet releasate compensate the age-induced decrease in cell proliferation of MSC?

Mesenchymal progenitor cells (MSCs) are promising for cell-based regeneration therapies. In elderly patients a reduced proliferation of MSCs has been described. Platelet-rich plasma (PRP) contains important factors necessary for osteogenic regeneration. The aim of this study was to find out whether the age-induced decrease in cell proliferation can be compensated by the use of supernatant of centrifuged, activated PRP (tPR). MSCs of donors of three age groups (A: young, 14-16 years, B: middle age, 36-46 years, C: older, 74-83 years) were expanded with 20% FCS alone or supplemented with thrombin-activated platelet releasate (tPR) (1%, 2.5%, and 5%) or platelet-poor plasma (PPP 5%). Cell proliferation and differentiation was measured on days 0, 3, and 7. Proliferation increased significantly in groups A and B with tPR, and non-significantly in group C. The generation times of MSCs of elderly patients were significantly increased in group C compared to groups A and B. Addition of 1% or 2.5% tPR significantly reduced population doubling times of all age groups. Adding tPR stimulates the proliferation rate of MSCs independent of donor age. For juvenile and middle-aged patients this influence was significant. Cells differentiation into osteoblasts was not influenced by addition of tPR.

Biometrical analysis of the shoulder joint regarding glenoid implant dimensions for arthroplasty

PURPOSE

Reduced bone stock and difficult intraoperative orientation are challenges in glenoid replacement surgery. New implant designs and methods for fixation, such as locking screws, extra-long central pegs and/or central compression screws are targeting these issues. The objective of this study is the analysis of the glenoid dimension regarding maximum central peg diameter and peg length (PL), and maximum screw length (SL) for glenoid fixation.

METHODS

Retrospective analysis of magnetic resonance imaging (n = 50) scans. Measurement of the maximum inferior glenoid diameter (GD), SL, maximum length of a 9.9, 10 and 11.4 mm central peg (PL) in the transverse plane; glenoid version (GV), humeral head diameter (HHD). Two independent measurements.

RESULTS

Mean age: 49.0 ± 15.7 years (17-80) (n = 20 female, 49.6 ± 16.0; n = 30 male, 48.6 ± 15.7). Mean values of measurement were GD: 28.9 ± 3.7 mm (21-39); SL: 34.1 ± 4.9 mm (26-44); PL 9.9 mm: 19.4 ± 4.3 mm (9-30); PL 10 mm: 19.0 ± 4.4 mm (8-30); PL 11.4 mm: 16.5 ± 4.1 mm (7-26) with significant gender differences (p = 0.001; p = 0.022; p = 0.001); GV: -0.6° ± 4.9° (-10 to 11); HHD: 50.0 mm ± 4.9 (41-61). There was good correlation between PL and SL (r = 0.32, p = 0.024) and for GD and PL (r = 0.61, p = 0.001; r = 0.57, p = 0.001; r = 0.96, p = 0.001). The ratio of HHD and GD was very constant with 0.6 ± 0.07.

CONCLUSIONS

These data indicate the high interindividual variability of glenoid morphology including significant gender-related differences. The good correlation between humeral head size and GD and maximum central PL can be helpful for cases with reduced bone stock in decision-making about implant size and bone grafting.

What is the predictive value of MRI for the occurrence of knee replacement surgery in knee osteoarthritis?

Knee osteoarthritis is associated with structural changes in the joint. Despite its many drawbacks, radiography is the current standard for evaluating joint structure in trials of potential disease-modifying osteoarthritis drugs. MRI is a non-invasive alternative that provides comprehensive imaging of the whole joint. Frequently used MRI measurements in knee osteoarthritis are cartilage volume and thickness; others include synovitis, synovial fluid effusions, bone marrow lesions (BML) and meniscal damage. Joint replacement is considered a clinically relevant outcome in knee osteoarthritis; however, its utility in clinical trials is limited. An alternative is virtual knee replacement on the basis of symptoms and structural damage. MRI may prove to be a good alternative to radiography in definitions of knee replacement. One of the MRI parameters that predicts knee replacement is medial compartment cartilage volume/thickness, which correlates with radiographic joint space width, is sensitive to change, and predicts outcomes in a continuous manner. Other MRI parameters include BML and meniscal lesions. MRI appears to be a viable alternative to radiography for the evaluation of structural changes in knee osteoarthritis and prediction of joint replacement.