Recruitment and baseline characteristics of young adults at risk of early-onset knee osteoarthritis after ACL reconstruction in the SUPER-Knee trial.

Objectives: The study aims to (1) report the process of recruiting young adults into a secondary knee osteoarthritis prevention randomised controlled trial (RCT) after anterior cruciate ligament reconstruction (ACLR); (2) determine the number of individuals needed to be screened to include one participant (NNS) and (3) report baseline characteristics of randomised participants. Methods: The SUpervised exercise-therapy and Patient Education Rehabilitation (SUPER)-Knee RCT compares SUPER and minimal intervention for young adults (aged 18-40 years) with ongoing symptoms (ie, mean score of <80/100 from four Knee injury and Osteoarthritis Outcome Score subscales (KOOS4)) 9-36 months post-ACLR. The NNS was calculated as the number of prospective participants screened to enrol one person. At baseline, participants provided medical history, completed questionnaires (demographic, injury/surgery, rehabilitation characteristics) and underwent physical examination. Results: 1044 individuals were screened to identify 567 eligible people, from which 184 participants (63% male) enrolled. The sample of enrolled participants was multicultural (29% born outside Australia; 2% Indigenous Australians). The NNS was 5.7. For randomised participants, mean±SD age was 30±6 years. The mean body mass index was 27.3±5.2 kg/m2, with overweight (43%) and obesity (21%) common. Participants were, on average, 2.3 years post-ACLR. Over half completed <8 months of postoperative rehabilitation, with 56% having concurrent injury/surgery to meniscus and/or cartilage. The most affected KOOS (0=worst, 100=best) subscale was quality of life (mean 43.7±19.1). Conclusion: Young adults post-ACLR were willing to participate in a secondary osteoarthritis prevention trial. Sample size calculations should be multiplied by at least 5.7 to provide an estimate of the NNS. The SUPER-Knee cohort is ideally positioned to monitor and intervene in the early development and trajectory of osteoarthritis. Trial registration number: ACTRN12620001164987.

Imaging-based assessment of fatty acid composition in human bone marrow adipose tissue at 7 T: Method comparison and in vivo feasibility.

PURPOSE: To demonstrate the feasibility and accuracy of chemical shift-encoded imaging of the fatty acid composition (FAC) of human bone marrow adipose tissue at 7 T, and to determine suitable image-acquisition parameters using simulations. METHODS: The noise performance of FAC estimation was investigated using simulations with a range of inter-echo time, and accuracy was assessed using a phantom experiment. Furthermore, one knee of 8 knee-healthy subjects (ages 35-54 years) was imaged, and the fractions of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) were mapped. Values were compared between reconstruction methods, and between anatomical regions. RESULTS: Based on simulations, ΔTE = 0.6 ms was chosen. The phantom experiment demonstrated high accuracy of especially SFA using a constrained reconstruction model (slope = 1.1, average bias = -0.2%). The lowest accuracy was seen for PUFA using a free model (slope = 2.0, average bias = 9.0%). For in vivo images, the constrained model resulted in lower intersubject variation compared with the free model (e.g., in the femoral shaft, the SFA percent-point range was within 1.0% [vs. 3.0%]). Furthermore, significant regional FAC differences were detected. For example, using the constrained approach, the femoral SFA in the medial condyle was lower compared with the shaft (median [range]: 27.9% [27.1%, 28.4%] vs. 32.5% [31.8%, 32.8%]). CONCLUSION: Bone marrow adipose tissue FAC quantification using chemical-shift encoding is feasible at 7 T. Both the noise performance and accuracy of the technique are superior using a constrained signal model.

Improved visualization of the bone-implant interface and osseointegration in ex vivo acetabular cup implants using photon-counting detector CT.

BACKGROUND: Successful osseointegration of joint replacement implants is required for long-term implant survival. Accurate assessment of osseointegration could enable clinical discrimination of failed implants from other sources of pain avoiding unnecessary surgeries. Photon-counting detector computed tomography (PCD-CT) provides improvements in image resolution compared to conventional energy-integrating detector CT (EID-CT), possibly allowing better visualization of bone-implant-interfaces and osseointegration. The aim of this study was to assess the quality of visualization of bone-implant-interfaces and osseointegration in acetabular cup implants, using PCD-CT compared with EID-CT. METHODS: Two acetabular implants (one cemented, one uncemented) retrieved during revision surgery were scanned using PCD-CT and EID-CT at equal radiation dose. Images were reconstructed using different reconstruction kernels and iterative strengths. Delineation of the bone-implant and bone-cement-interface as an indicator of osseointegration was scored subjectively for image quality by four radiologists on a Likert scale and assessed quantitatively. RESULTS: Delineation of bone-implant and bone-cement-interfaces was better with PCD-CT compared with EID-CT (p ≤ 0.030). The highest ratings were given for PCD-CT at sharper kernels for the cemented cup (PCD-CT, median 5, interquartile range 4.25-5.00 versus EID-CT, 3, 2.00-3.75, p < 0.001) and the uncemented cup (5, 4.00-5.00 versus 2, 2-2, respectively, p < 0.001). The bone-implant-interface was 35-42% sharper and the bone-cement-interface was 28-43% sharper with PCD-CT compared with EID-CT, depending on the reconstruction kernel. CONCLUSIONS: PCD-CT might enable a more accurate assessment of osseointegration of orthopedic joint replacement implants. KEY POINTS: • The bone-implant interface ex vivo showed superior visualization using photon-counting detector computed tomography (PCD-CT) compared to energy-integrating detector computed tomography. • Harder reconstruction kernels in PCD-CT provide sharper images with lower noise levels. • These improvements in imaging might make it possible to visualize osseointegration in vivo.

Trajectory of knee health in runners with and without heightened osteoarthritis risk: the TRAIL prospective cohort study protocol.

INTRODUCTION: Running is one of the most popular recreational activities worldwide, due to its low cost and accessibility. However, little is known about the impact of running on knee joint health in runners with and without a history of knee surgery. The primary aim of this longitudinal cohort study is to compare knee joint structural features on MRI and knee symptoms at baseline and 4-year follow-up in runners with and without a history of knee surgery. Secondary aims are to explore the relationships between training load exposures (volume and/or intensity) and changes in knee joint structure and symptoms over 4 years; explore the relationship between baseline running biomechanics, and changes in knee joint structure and symptoms over 4 years. In addition, we will explore whether additional variables confound, modify or mediate these associations, including sex, baseline lower-limb functional performance, knee muscle strength, psychological and sociodemographic factors. METHODS AND ANALYSIS: A convenience sample of at least 200 runners (sex/gender balanced) with (n=100) and without (n=100) a history of knee surgery will be recruited. Primary outcomes will be knee joint health (MRI) and knee symptoms (baseline; 4 years). Exposure variables for secondary outcomes include training load exposure, obtained daily throughout the study from wearable devices and three-dimensional running biomechanics (baseline). Additional variables include lower limb functional performance, knee extensor and flexor muscle strength, biomarkers, psychological and sociodemographic factors (baseline). Knowledge and beliefs about osteoarthritis will be obtained through predefined questions and semi-structured interviews with a subset of participants. Multivariable logistic and linear regression models, adjusting for potential confounding factors, will explore changes in knee joint structural features and symptoms, and the influence of potential modifiers and mediators. ETHICS AND DISSEMINATION: Approved by the La Trobe University Ethics Committee (HEC-19524). Findings will be disseminated to stakeholders, peer-review journals and conferences.

Effect of Curcuma longa extract on serum inflammatory markers and MRI-based synovitis in knee osteoarthritis: secondary analyses from the CurKOA randomised trial.

BACKGROUND: Curcuma longa (CL) extract is modestly effective for relieving knee symptoms in knee osteoarthritis (OA) patients; however, its mechanism of action is unclear. PURPOSE: We aimed to determine the effects of CL treatment on serum inflammatory markers over 12 weeks and to explore its potential effects on synovitis assessed by contrast-enhanced magnetic resonance imaging (CE-MRI) of the knee. METHODS: Secondary analyses were conducted on the CL for knee OA (CurKOA) trial, which compared CL (n = 36) and placebo (n = 34) over 12 weeks for the treatment of knee OA. Systemic inflammatory markers (TNFα, IL6, and hsCRP) and a cartilage extracellular matrix degradative enzyme (MMP-3) were measured. A subgroup of participants (CL, n = 7; placebo, n = 5) underwent CE-MRI at baseline and a 12-week follow-up. RESULTS: Over 12 weeks, there were no between-group differences in change in hsCRP, IL-6, and TNFα levels. MMP-3 levels decreased in both CL (-1.31 ng/ml [95%CI: -1.89 to -0.73]) and placebo (-2.34 ng/ml [95%CI: -2.95 to -1.73]) groups, with the placebo group having a slightly greater decrease (1.03 ng/ml [95%CI: 0.19 to 1.88]). Most (10 of 12) sub-study participants had normal synovial thickness scores at baseline. One participant had mild synovitis in each of the placebo and CL groups. Synovitis status was stable for all except two participants, one each in the CL and placebo group, whose synovitis score increased. CONCLUSION: This is the first study that explored the effect of CL treatment on local and systemic inflammation using biochemical markers and CE-MRI outcomes on knee OA patients. Secondary analyses from this pilot study suggest that CL is unlikely to have clinically significant effects on systemic (inflammatory and cartilage) or local synovitis (CE-MRI) biomarkers compared to placebo. The mechanism of action for CL effect on pain remains unclear.

The prevalence of incidental findings on pelvis MRI of 8-13-year-old children.

BACKGROUND: The prevalence and clinical relevance of incidental findings (IF(s)) on imaging assessing the pelvis in children has not been well documented. METHODS: Three-thousand two-hundred thirty-one children (mean age 10.2 (range 8.6-12.9) years) were evaluated with MRI of the hips, pelvis, and lumbar spine, as part of a prospective population-based pediatric cohort study. Scans were reviewed by trained medical staff for abnormalities. IFs were categorized by clinical relevance and need for further clinical evaluation. RESULTS: 8.3% (n = 267) of children featured at least one IF. One or more musculoskeletal IFs were found in 7.9% (n = 254) of children, however, only 0.8% (n = 2) of musculoskeletal IFs required clinical evaluation. Most frequent abnormalities were simple bone cysts 6.0% (n = 195), chondroid lesions 0.6% (n = 20), and perineural cysts 0.5% (n = 15). Intra-abdominal IFs were detected in 0.5% (n = 17) of children, with over half (n = 9) of these requiring evaluation. The three most common intra-abdominal IFs were a duplex collecting system 0.09% (n = 3), significant ascites 0.06% (n = 2), and hydroureteronephrosis 0.06% (n = 2). CONCLUSIONS: IFs on MRI of the lower abdominal and hip region are relatively common in children aged 8-13 years, most of these can be confidently categorized as clinically irrelevant without the need for additional clinical or radiologic follow up. IMPACT: Our research contributes greatly to the knowledge of the prevalence of (asymptomatic) pathology in children. We evaluated MR images of 3231 children, covering hip joints, pelvic skeleton, lower and mid-abdomen, and lumbar and lower thoracic spine as part of a population study. One or more musculoskeletal incidental finding were found in 7.9% of children. Most of these can be confidently categorized as clinically irrelevant without the need for additional follow up. However 0.8% of musculoskeletal findings required further evaluation. Intra-abdominal incidental findings were detected in 0.5% of children, with over half of the abdominal and urogenital findings requiring further evaluation.

Assessment of visibility of bone structures in the wrist using normal and half of the radiation dose with photon-counting detector CT.

PURPOSE: To quantitatively and qualitatively assess the visibility of bone structures in the wrist on photon-counting detector computed tomography (PCD-CT) images compared to state-of-the-art energy-integrating detector CT (EID-CT). METHOD: Four human cadaveric wrist specimens were scanned with EID-CT and PCD-CT at identical CTDIvol of 12.2 mGy and with 6.1 mGy (half dose PCD-CT). Axial images were reconstructed using the thinnest possible slice thickness, i.e. 0.4 mm on EID-CT and 0.2 mm on PCD-CT, with the largest image matrix size possible using reconstruction kernels optimized for bone (EID-CT: Ur68, PCD-CT: Br92). Quantitative evaluation was performed to determine contrast-noise ratio (CNR) of bone/ fat, cortical and trabecular sharpness. An observer study using visual grading characteristics (VGC) analysis was performed by six observers to assess the visibility of nutrient canals, trabecular architecture, cortical bone and the general image quality. RESULTS: At equal dose, images obtained with PCD-CT had 39 ± 6 % lower CNR (p = 0.001), 71 ± 57 % higher trabecular sharpness in the radius (p = 0.02) and 42 ± 8 % (p < 0.05) sharper cortical edges than those obtained with EID-CT. This was confirmed by VGC analysis showing a superior visibility of nutrient canals, trabeculae and cortical bone area under the curve (AUC) > 0.89) for PCD-CT, even at half dose. CONCLUSIONS: Despite a lower CNR and increased noise, the trabecular and cortical sharpness were twofold higher with PCD-CT. Visual grading analysis demonstrated superior visibility of cortical bone, trabeculae, nutrient canals and an overall improved image quality with PCD-CT over EID-CT. At half dose, PCD-CT also yielded superior image quality, both in quantitative measures and as evaluated by radiologists.

Standardised lesion segmentation for imaging biomarker quantitation: a consensus recommendation from ESR and EORTC.

BACKGROUND: Lesion/tissue segmentation on digital medical images enables biomarker extraction, image-guided therapy delivery, treatment response measurement, and training/validation for developing artificial intelligence algorithms and workflows. To ensure data reproducibility, criteria for standardised segmentation are critical but currently unavailable. METHODS: A modified Delphi process initiated by the European Imaging Biomarker Alliance (EIBALL) of the European Society of Radiology (ESR) and the European Organisation for Research and Treatment of Cancer (EORTC) Imaging Group was undertaken. Three multidisciplinary task forces addressed modality and image acquisition, segmentation methodology itself, and standards and logistics. Devised survey questions were fed via a facilitator to expert participants. The 58 respondents to Round 1 were invited to participate in Rounds 2-4. Subsequent rounds were informed by responses of previous rounds. RESULTS/CONCLUSIONS: Items with ≥ 75% consensus are considered a recommendation. These include system performance certification, thresholds for image signal-to-noise, contrast-to-noise and tumour-to-background ratios, spatial resolution, and artefact levels. Direct, iterative, and machine or deep learning reconstruction methods, use of a mixture of CE marked and verified research tools were agreed and use of specified reference standards and validation processes considered essential. Operator training and refreshment were considered mandatory for clinical trials and clinical research. Items with a 60-74% agreement require reporting (site-specific accreditation for clinical research, minimal pixel number within lesion segmented, use of post-reconstruction algorithms, operator training refreshment for clinical practice). Items with ≤ 60% agreement are outside current recommendations for segmentation (frequency of system performance tests, use of only CE-marked tools, board certification of operators, frequency of operator refresher training). Recommendations by anatomical area are also specified.

T2 mapping of healthy knee cartilage: multicenter multivendor reproducibility.

BACKGROUND: T2 mapping is increasingly used to quantify cartilage degeneration in knee osteoarthritis (OA), yet reproducibility studies in a multicenter setting are limited. The purpose of this study was to determine the longitudinal reproducibility and multicenter variation of cartilage T2 mapping, using various MRI equipment and acquisition protocols. METHODS: In this prospective multicenter study, four traveling, healthy human subjects underwent T2 mapping twice at five different centers with a 6-month-interval. Centers had various MRI scanners, field strengths, and T2 mapping acquisition protocols. Mean T2 values were calculated in six cartilage regions of interest (ROIs) as well as an average value per patient. A phantom was scanned once at each center. To evaluate longitudinal reproducibility, intraclass correlation coefficients (ICC), root-mean-square coefficient of variation (RMS-CV), and a Bland-Altman plot were used. To assess the variation of in vivo and phantom T2 values across centers, ANOVA was performed. RESULTS: ICCs of the T2 mapping measurements per ROI and the ROI's combined ranged from 0.73 to 0.91, indicating good to excellent longitudinal reproducibility. RMS-CVs ranged from 1.1% to 1.5% (per ROI) and 0.6% to 1.6% (ROIs combined) across the centers. A Bland-Altman plot did not reveal a systematic error. Evident, but consistent, discrepancies in T2 values were observed across centers, both in vivo and in the phantom. CONCLUSIONS: The results of this study suggest that T2 mapping can be used to longitudinal assess cartilage degeneration in multicenter studies. Given the differences in absolute cartilage T2 values across centers, absolute T2 values derived from various centers in multicenter multivendor trials should not be pooled.

Quantitative volume and dynamic contrast-enhanced MRI derived perfusion of the infrapatellar fat pad in patellofemoral pain.

BACKGROUND: Patellofemoral pain (PFP) is a common knee condition and possible precursor of knee osteoarthritis (OA). Inflammation, leading to an increased perfusion, or increased volume of the infrapatellar fat pad (IPFP) may induce knee pain. The aim of the study was to compare quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters, as imaging biomarkers of inflammation, and volume of the IPFP between patients with PFP and controls and between patients with and without IPFP edema or joint effusion. METHODS: Patients with PFP and healthy controls were included and underwent non-fat suppressed 3D fast-spoiled gradient-echo (FSPGR) and DCE-MRI. Image registration was applied to correct for motion. The IPFP was delineated on FSPGR using Horos software. Volume was calculated and quantitative perfusion parameters were extracted by fitting extended Tofts' pharmacokinetic model. Differences in volume and DCE-MRI parameters between patients and controls were tested by linear regression analyses. IPFP edema and effusion were analyzed identically. RESULTS: Forty-three controls and 35 PFP patients were included. Mean IPFP volume was 26.04 (4.18) mL in control subjects and 27.52 (5.37) mL in patients. Median Ktrans was 0.017 (0.016) min-1 in control subjects and 0.016 (0.020) min-1 in patients. None of the differences in volume and perfusion parameters were statistically significant. Knees with effusion showed a higher perfusion of the IPFP compared to knees without effusion in patients only. CONCLUSIONS: The IPFP has been implicated as source of knee pain, but higher DCE-MR blood perfusion, an imaging biomarker of inflammation, and larger volume are not associated with PFP. Patient's knees with effusion showed a higher perfusion, pointing towards inflammation.

Quantitative subchondral bone perfusion imaging in knee osteoarthritis using dynamic contrast enhanced MRI.

OBJECTIVE: Subchondral bone changes, characterized by increased bone turnover and vascularity, are believed to stimulate progression and pain in knee osteoarthritis (OA). The objective of this study was to evaluate the bone perfusion in knee OA using quantitative dynamic contrast enhanced MRI (DCE-MRI). DESIGN: Unicompartmental knee OA patients were included and underwent 3 Tesla DCE-MRI and T2-weighted MRI. Quantitative DCE-MRI analysis of Ktrans and Kep, representing perfusion parameters, was performed to evaluate differences between the most and least affected knee compartment. First, DCE-MRI parameter differences between epimetaphyseal and subchondral bone in both femur and tibia were assessed. Second, DCE-MRI parameters in subchondral bone marrow lesions (BMLs) were compared to surrounding subchondral bone without BMLs. RESULTS: Twenty-three patients were analyzed. Median Ktrans and Kep in epimetaphyseal bone were significantly higher (p < 0.05) in the most affected (Ktrans: 0.014; Kep: 0.054 min-1) compared to least affected (Ktrans: 0.010; Kep: 0.016 min-1) compartment. For subchondral bone, DCE-MRI parameters were significantly higher (p < 0.05) in the most affected (Ktrans: 0.019; Kep: 0.091 min-1) compared to least affected (Ktrans: 0.014; Kep: 0.058 min-1) compartment as well. Subchondral BMLs detected on fat-saturated T2-weighted images were present in all patients. Median Ktrans (0.091 vs 0.000 min-1) and Kep (0.258 vs 0.000 min-1) were significantly higher within subchondral BMLs compared to surrounding subchondral bone without BMLs (p < 0.001). CONCLUSIONS: Increased perfusion parameters in epimetaphyseal bone, subchondral bone and BMLs are observed in unicompartmental knee OA. BMLs likely account for most of the effect of the higher bone perfusion in knee OA.

T2 mapping of the meniscus is a biomarker for early osteoarthritis.

PURPOSE: To evaluate in vivo T2 mapping as quantitative, imaging-based biomarker for meniscal degeneration in humans, by studying the correlation between T2 relaxation time and degree of histological degeneration as reference standard. METHODS: In this prospective validation study, 13 menisci from seven patients with radiographic knee osteoarthritis (median age 67 years, three males) were included. Menisci were obtained during total knee replacement surgery. All patients underwent pre-operative magnetic resonance imaging using a 3-T MR scanner which included a T2 mapping pulse sequence with multiple echoes. Histological analysis of the collected menisci was performed using the Pauli score, involving surface integrity, cellularity, matrix organization, and staining intensity. Mean T2 relaxation times were calculated in meniscal regions of interest corresponding with the areas scored histologically, using a multi-slice multi-echo postprocessing algorithm. Correlation between T2 mapping and histology was assessed using a generalized least squares model fit by maximum likelihood. RESULTS: The mean T2 relaxation time was 22.4 ± 2.7 ms (range 18.5-27). The median histological score was 10, IQR 7-11 (range 4-13). A strong correlation between T2 relaxation time and histological score was found (rs = 0.84, CI 95% 0.64-0.93). CONCLUSION: In vivo T2 mapping of the human meniscus correlates strongly with histological degeneration, suggesting that T2 mapping enables the detection and quantification of early compositional changes of the meniscus in knee OA. KEY POINTS: • Prospective histology-based study showed that in vivo T 2 mapping of the human meniscus correlates strongly with histological degeneration. • Meniscal T 2 mapping allows detection and quantifying of compositional changes, without need for contrast or special MRI hardware. • Meniscal T 2 mapping provides a biomarker for early OA, potentially allowing early treatment strategies and prevention of OA progression.

Cartilage Imaging: Techniques and Developments.

Cartilage degeneration is one of the most common chronic age-related joint disorders leading to pain and reduced joint motion. The increasing prevalence of osteoarthritis requires accurate cartilage imaging, both clinically and in research. Detailed cartilage imaging is also necessary for traumatic cartilage lesions and for pre- and postoperative assessment of cartilage repair procedures. Although still widely used, conventional radiography bears significant limitations because it assesses cartilage indirectly by joint space width. Magnetic resonance imaging (MRI) enables direct visualization of cartilage damage along with other concomitantly affected joint tissues. Several semiquantitative grading systems and volumetric analysis methods exist to assess cartilage damage and cartilage repair on MRI. Quantification of hyaline and fibrocartilage biochemical composition is possible with novel MRI methods such as T2- and T1ρ-mapping, delayed gadolinium-enhanced MRI of cartilage, glycosaminoglycan chemical exchange saturation transfer, and sodium imaging, along with quantitative computed tomography arthrography. These techniques provide promising quantitative imaging biomarkers that can detect early cartilage changes before morphological alterations occur.

Predictive Factors of Hamstring Tendon Regeneration and Functional Recovery After Harvesting: A Prospective Follow-up Study.

BACKGROUND: Semitendinosus and gracilis tendons may regenerate after harvesting for ligament reconstruction procedures. However, predictive factors of tendon regeneration and the extent of functional recovery remain unclear. PURPOSE: To identify predictive factors for hamstring tendon regeneration and to examine the morbidity of nonregenerated hamstring tendons. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Of the 154 patients who were included in a prospective follow-up study, 79 underwent reconstruction of the anterior cruciate ligament entailing the hamstring tendons and met the following inclusion criteria: (1) anterior cruciate ligament rupture diagnosed by physical examination and magnetic resonance imaging (MRI), (2) MRI within 6 months after trauma, (3) age between 18 and 45 years, and (4) 2-year follow-up MRI data available. Hamstring tendon regeneration was assessed as complete if a tendon-like structure could be visualized at the level of the joint line or more cranially. Patient characteristics-such as age, sex, body mass index, alcohol/nicotine use, activity level (Tegner scores), and functional instability (1-legged hop test)-were evaluated preoperatively and at 2 years to determine predictive factors for tendon regeneration or examine functional recovery of hamstring tendon regeneration. RESULTS: At 2 years' follow-up, 67.1% of the patients showed regeneration of semitendinosus tendons, 81.0% of gracilis tendons, and 59.5% of both tendons. The likelihood of semitendinosus tendon regeneration significantly decreased with aging (odds ratio [OR], 0.92 change per year of age; 95% CI, 0.84-0.99; P = .03) and smoking (OR, 0.20; 95% CI, 0.05-0.77; P = .02). No predictive factor was found for gracilis tendon regeneration. Regeneration of the semitendinosus and gracilis tendons was negatively related with smoking (OR, 0.22; 95% CI, 0.06-0.79; P = .02). Patients without regeneration showed similar postoperative visual analog scale scores during physical activity, similar Tegner scores, and a significant decrease of the upper leg circumference, as compared with their preoperative results. Regardless of the regeneration status, 1-legged hop test results significantly increased at 2-year follow-up. CONCLUSION: Hamstring tendon regeneration occurs less frequently in older patients and in smokers. However, absence of regenerated tendons does not seem to cause a loss of function.

Five-minute knee MRI for simultaneous morphometry and T2 relaxometry of cartilage and meniscus and for semiquantitative radiological assessment using double-echo in steady-state at 3T.

BACKGROUND: Biomarkers for assessing osteoarthritis activity necessitate multiple MRI sequences with long acquisition times. PURPOSE: To perform 5-minute simultaneous morphometry (thickness/volume measurements) and T2 relaxometry of both cartilage and meniscus, and semiquantitative MRI Osteoarthritis Knee Scoring (MOAKS). STUDY TYPE: Prospective. SUBJECTS: Fifteen healthy volunteers for morphometry and T2 measurements, and 15 patients (five each Kellgren-Lawrence grades 0/2/3) for MOAKS assessment. FIELD STRENGTH/SEQUENCE: A 5-minute double-echo steady-state (DESS) sequence was evaluated for generating quantitative and semiquantitative osteoarthritis biomarkers at 3T. ASSESSMENT: Flip angle simulations evaluated tissue signals and sensitivity of T2 measurements. Morphometry and T2 reproducibility was compared against morphometry-optimized and relaxometry-optimized sequences. Repeatability was assessed by scanning five volunteers twice. MOAKS reproducibility was compared to MOAKS derived from a clinical knee MRI protocol by two readers. STATISTICAL TESTS: Coefficients of variation (CVs), concordance confidence intervals (CCI), and Wilcoxon signed-rank tests compared morphometry and relaxometry measurements with their reference standards. DESS MOAKS positive percent agreement (PPA), negative percentage agreement (NPA), and interreader agreement was calculated using the clinical protocol as a reference. Biomarker variations between Kellgren-Lawrence groups were evaluated using Wilcoxon rank-sum tests. RESULTS: Cartilage thickness (P = 0.65), cartilage T2 (P = 0.69), and meniscus T2 (P = 0.06) did not significantly differ from their reference standard (with a 20° DESS flip angle). DESS slightly overestimated meniscus volume (P < 0.001). Accuracy and repeatability CVs were <3.3%, except the meniscus T2 accuracy (7.6%). DESS MOAKS had substantial interreader agreement and high PPA/NPA values of 87%/90%. Bone marrow lesions and menisci had slightly lower PPAs. Cartilage and meniscus T2 , and MOAKS (cartilage surface area, osteophytes, cysts, and total score) was higher in Kellgren-Lawrence groups 2 and 3 than group 0 (P < 0.05). DATA CONCLUSION: The 5-minute DESS sequence permits MOAKS assessment for a majority of tissues, along with repeatable and reproducible simultaneous cartilage and meniscus T2 relaxometry and morphometry measurements. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1328-1341.

Impact of total knee replacement practice: cost effectiveness analysis of data from the Osteoarthritis Initiative.

Objectives To evaluate the impact of total knee replacement on quality of life in people with knee osteoarthritis and to estimate associated differences in lifetime costs and quality adjusted life years (QALYs) according to use by level of symptoms.Design Marginal structural modeling and cost effectiveness analysis based on lifetime predictions for total knee replacement and death from population based cohort data.Setting Data from two studies-Osteoarthritis Initiative (OAI) and the Multicenter Osteoarthritis Study (MOST)-within the US health system.Participants 4498 participants with or at high risk for knee osteoarthritis aged 45-79 from the OAI with no previous knee replacement (confirmed by baseline radiography) followed up for nine years. Validation cohort comprised 2907 patients from MOST with two year follow-up.Intervention Scenarios ranging from current practice, defined as total knee replacement practice as performed in the OAI (with procedural rates estimated by a prediction model), to practice limited to patients with severe symptoms to no surgery.Main outcome measures Generic (SF-12) and osteoarthritis specific quality of life measured over 96 months, model based QALYs, costs, and incremental cost effectiveness ratios over a lifetime horizon.Results In the OAI, total knee replacement showed improvements in quality of life with small absolute changes when averaged across levels of confounding variables: 1.70 (95% uncertainty interval 0.26 to 3.57) for SF-12 physical component summary (PCS); -10.69 (-13.39 to -8.01) for Western Ontario and McMaster Universities arthritis index (WOMAC); and 9.16 (6.35 to 12.49) for knee injury and osteoarthritis outcome score (KOOS) quality of life subscale. These improvements became larger with decreasing functional status at baseline. Provision of total knee replacement to patients with SF-12 PCS scores <35 was the optimal scenario given a cost effectiveness threshold of $200 000/QALY, with cost savings of $6974 ($5789 to $8269) and a minimal loss of 0.008 (-0.056 to 0.043) QALYs compared with current practice. These findings were reproduced among patients with knee osteoarthritis from the MOST cohort and were robust against various scenarios including increased rates of total knee replacement and mortality and inclusion of non-healthcare costs but were sensitive to increased deterioration in quality of life without surgery. In a threshold analysis, total knee replacement would become cost effective in patients with SF-12 PCS scores ≤40 if the associated hospital admission costs fell below $14 000 given a cost effectiveness threshold of $200 000/QALY.Conclusion Current practice of total knee replacement as performed in a recent US cohort of patients with knee osteoarthritis had minimal effects on quality of life and QALYs at the group level. If the procedure were restricted to more severely affected patients, its effectiveness would rise, with practice becoming economically more attractive than its current use.

Cam Deformity and Acetabular Dysplasia as Risk Factors for Hip Osteoarthritis.

OBJECTIVE: Cam deformity and acetabular dysplasia have been recognized as relevant risk factors for hip osteoarthritis (OA) in a few prospective studies with limited sample sizes. To date, however, no evidence is available from prospective studies regarding whether the magnitude of these associations differs according to sex, body mass index (BMI), and age. METHODS: Participants in the Rotterdam Study cohort including men and women ages 55 years or older without OA at baseline (n = 4,438) and a mean follow-up of 9.2 years were included in the study. Incident radiographic OA was defined as a Kellgren/Lawrence grade of ≥2 or a total hip replacement at follow-up. Alpha and center-edge angles were measured to determine the presence of cam deformity and acetabular dysplasia/pincer deformity, respectively. Odds ratios (ORs) were calculated to assess the associations between both deformities and the development of OA. RESULTS: Subjects with cam deformity (OR 2.11, 95% confidence interval [95% CI] 1.55-2.87) and those with acetabular dysplasia (OR 2.19, 95% CI 1.50-3.21) had a 2-fold increased risk of developing OA compared with subjects without deformity, while pincer deformity did not increase the risk of OA. Stratification analyses showed that the associations of cam deformity and acetabular dysplasia with OA were driven by younger individuals, whereas BMI did not influence the associations. Female sex appears to modify the risk of hip OA related to acetabular dysplasia. CONCLUSION: Individuals with cam deformity and those with acetabular dysplasia are predisposed to OA; these associations were independent of other well-known risk factors. Interestingly, both deformities predisposed to OA only in relatively young individuals. Therefore, early identification of these conditions is important.