Significance of preradiographic magnetic resonance imaging lesions in persons at increased risk of knee osteoarthritis

Predicting incident radiographic knee osteoarthritis through quantitative meniscal lesion parameters: data from the osteoarthritis initiative

BACKGROUND

This study investigates the potential of novel meniscal parameters as predictive factors for incident radiographic knee osteoarthritis (ROA) over a span of four years, as part of the Osteoarthritis Initiative (OAI) study.

OBJECTIVES

Quantitative measurements of meniscal parameters alteration could serve as predictors of OA's occurrence and progression.

METHODS AND MATERIALS

A nested matched case-control study design was used to select participants from OAI study. Case knees (n = 178) were defined as those with incident ROA (Kellgren Lawrence Grade (KLG) 0 or 1 at baseline (BL), evolving into KLG 2 or above by year 4). Control knees were matched one-to-one by sex, age and radiographic status with case knees. The mean distance from medial-to-lateral meniscal lesions [Mean(MLD)], mean value of tibial plateau width [Mean(TPW)] and the mean of the relative percentage of the medial-to-lateral meniscal lesions distance [Mean(RMLD)] were evaluated through coronal T2-weighted turbo spin echo (TSE) MRI at P-0 (visit when incident ROA was found on radiograph), P-1(one year prior to P-0) and baseline, respectively. Using the imaging data of one patient, the mechanism was investigated by finite element analysis.

RESULTS

Participants were on average 60.22 years old, predominantly female (66.7%) and overweight (mean BMI: 28.15). Mean(MLD) and Mean(RMLD) were significantly greater for incident knees compared to no incident knees at baseline, P-1 and P-0. [Mean(MLD), Mean(RMLD); (42.56-49.73) mean ± (7.70-9.52) mm SD vs. (38.14-40.78) mean ± (5.51-7.05)mm SD; (58.61-68.95) mean ± (8.52-11.40) mm SD vs. (52.52-56.35) mean ± (6.53-7.85)mm SD, respectively]. Baseline Mean(MLD) and Mean(RMLD), [Adjusted OR, 95%CI: 1.11(1.07 to 1.16) and 1.13(1.09 to 1.17), respectively], were associated with incident ROA during 4 years, However, Mean(TPW) [Adjusted OR, 95%CI: 0.98(0.94 to 1.02)] was not associated with incident ROA during 4 years. While Mean(TPW) at P-1 and P-0 was not associated with the risk of incident ROA, Mean(MLD) and Mean(RMLD) at P-1 and P-0 were significantly positively associated with the risk of incident ROA.

CONCLUSIONS

The meniscal parameters alteration could be an important imaging biomarker to predict the occurrence of ROA.

Development of an Ultrasound Imaging Atlas for Grading Osteoarthritis in the First Metatarsophalangeal Joint

OBJECTIVE

Ultrasound (US) imaging may play a fundamental role in the earlier detection and assessment of first metatarsophalangeal joint (MTPJ) osteoarthritis (OA) because of its ability to depict tissue-specific morphologic changes before the point of irreversible structural damage. However, the role of US in supporting the diagnosis of OA in foot joints has not been clearly defined. The aims of this study were to develop a semiquantitative US atlas (the AUT ultrasound imaging [AUTUSI] atlas) to grade the degree of osteoarthritic change in the first MTPJ and to evaluate the intraexaminer and interexaminer reproducibility of using the atlas.

METHODS

US images were obtained from 57 participants (30 participants with radiographically confirmed first MTPJ OA). The AUTUSI atlas supports the examination of grading joint effusion, synovial hypertrophy, synovitis, osteophytes, joint space narrowing, and cartilage thickness. Six examiners used the atlas to independently grade 24 US images across 2 sessions. Intraexaminer and interexaminer reproducibility were determined using percentage agreement and Gwet's AC2.

RESULTS

Observations using the AUTUSI atlas demonstrated almost perfect-to-perfect interexaminer agreement (percentage agreement ranged from 96% to 100%, and Gwet's AC2 values ranged from 0.81 to 1.00) and moderate-to-perfect intraexaminer agreement (percentage agreement ranged from 67% to 100%, and Gwet's AC2 values ranged from 0.54 to 1.00).

CONCLUSION

The AUTUSI atlas demonstrated excellent intraexaminer and interexaminer reproducibility for evaluating first MTPJ joint effusion, synovial hypertrophy, synovitis, joint space narrowing, osteophytes, and cartilage thickness. The AUTUSI atlas affords an opportunity to detect prognostic markers of OA earlier in the disease cascade and has the potential to advance understanding of the pathologic process of first MTPJ OA.

Integrating Radiomics and Neural Networks for Knee Osteoarthritis Incidence Prediction

OBJECTIVE

Accurately predicting knee osteoarthritis (KOA) is essential for early detection and personalized treatment. We aimed to develop and test a magnetic resonance imaging (MRI)-based joint space (JS) radiomic model (RM) to predict radiographic KOA incidence through neural networks by integrating meniscus and femorotibial cartilage radiomic features.

METHODS

In the Osteoarthritis Initiative cohort, participants with knees without radiographic KOA at baseline but at high risk for radiographic KOA were included. Patients' knees developed radiographic KOA, whereas control knees did not over four years. We randomly split the participants into development and test cohorts (8:2) and extracted features from baseline three-dimensional double-echo steady-state sequence MRI. Model performance was evaluated using an area under the receiver operating characteristic curve (AUC), sensitivity, and specificity in both cohorts. Nine resident surgeons performed the reader experiment without/with the JS-RM aid.

RESULTS

Our study included 549 knees in the development cohort (275 knees of patients with KOA vs 274 knees of controls) and 137 knees in the test cohort (68 knees of patients with KOA vs 69 knees of controls). In the test cohort, JS-RM had a favorable accuracy for predicting the radiographic KOA incidence with an AUC of 0.931 (95% confidence interval [CI] 0.876-0.963), a sensitivity of 84.4% (95% CI 83.9%-84.9%), and a specificity of 85.6% (95% CI 85.2%-86.0%). The mean specificity and sensitivity of resident surgeons through MRI reading in predicting radiographic KOA incidence were increased from 0.474 (95% CI 0.333-0.614) and 0.586 (95% CI 0.429-0.743) without the assistance of JS-RM to 0.874 (95% CI 0.847-0.901) and 0.812 (95% CI 0.742-0.881) with JS-RM assistance, respectively (P < 0.001).

CONCLUSION

JS-RM integrating the features of the meniscus and cartilage showed improved predictive values in radiographic KOA incidence.

[Magnetic resonance imaging of the knee joint : What does the orthopedic surgeon expect from the radiologist?]

Magnet resonance imaging (MRI) offers a precise visualization of structural changes with high sensitivity and specificity. However, not all these soft tissue damages or bony lesions are clinically relevant or require treatment. Therefore, it is important to provide the radiologist with a specific clinical request when asking for an MRI examination of the knee. In this article, all important anatomical structures of the knee joint will be addressed with emphasis on the relevant questions for the radiologist. Based on the clinical examination, the MRI provides information about the damage of anatomical structures. This information is of utmost importance for therapeutic decision-making in order to allow an adequate and personalized treatment of patients.

The influence of meniscal pathology in the incidence of knee osteoarthritis: a review

IMPORTANCE

Knee osteoarthritis (OA) is a common cause of pain and disability in older persons, affecting approximately 14 million individuals in the USA. Meniscal damage is also common in this age group with a prevalence of 35% in a middle-aged and older community sample and 82% in persons with evidence of radiographic knee osteoarthritis. This paper systematically reviews evidence on the association of meniscal pathology and incident radiographic knee OA.

OBSERVATIONS

We included 15 articles, published between 2013 and 2021, assessing the relationship between meniscal pathology and OA incidence (Fig. 1). The menisci are crucial load-bearing structures, and the resulting increase in biomechanical stress due to meniscal damage increases the risk for OA development. While some discrepancies are present in the literature, a clinically meaningful association has been generally established between the presence of a meniscal tear or meniscal extrusion and subsequent development of incident OA. Of note, larger radial tears as well as complex and more severe tears exhibit the strongest association with the development of incident OA. The relationship between other features of meniscal morphology-such as meniscal volume and meniscal coverage-and incident OA is less clearly documented.

CONCLUSIONS AND RELEVANCE

The early detection of meniscal pathology can be used to trigger preventative and therapeutic strategies designed to avert or delay knee OA in this at-risk population.

Low-intensity pulsed ultrasound irradiation attenuates collagen degradation of articular cartilage in early osteoarthritis-like model mice

PURPOSE

Osteoarthritis (OA) is a combination of degeneration and destruction of articular cartilage due to mechanical stress, secondary synovitis, and bone remodelling. In recent years, early knee OA, a preliminary stage of structural failure in OA, has attracted attention as a potential target for therapy to prevent the onset of OA. Intra-articular administration of monoiodoacetic acid (MIA) induces OA-like symptoms, and low doses of MIA induce early OA like symptoms. In this experiment, a low-dose of MIA was induced to early OA model mice, which were then irradiated with low-intensity pulsed ultrasound (LIPUS) to examine whether LIPUS improves symptoms of early OA.

METHODS

After 4 weeks of LIPUS irradiation, articular cartilage was observed at 1 and 4 weeks. The Osteoarthritis Research Society International (OARSI) scores were calculated using Safranin-O staining results. Cartilage degeneration was detected using Denatured Collagen Detection Reagent (DCDR).

RESULTS

We observed a significant decrease in OARSI scores in the LIPUS irradiated group at week 4. The non-LIPUS group showed widespread areas of double positivity for Type II collagen and DCDR, whereas the LIPUS group showed only a small number of DCDR-positive areas. In addition, macrophage numbers counted in the articular capsule at week 1 showed a significant decrease in the LIPUS irradiated group. Lubricin detection showed that lubricin positive cell number was significantly increased by LIPUS irradiation at week 4.

CONCLUSIONS

These results suggest that LIPUS attenuates cartilage degeneration in early OA by relieving inflammation and enhancing the inhibitory effect of lubricin on cartilage degeneration.

Morphological analysis of three-dimensional MR images of patellofemoral joints in asymptomatic subjects

The existing methods for analyzing patellofemoral (PF) osteoarthritis (OA) are limited. Our purpose was to clarify the frequency, localization, and morphological progression of PFOA by observing three-dimensional (3D) magnetic resonance (MR) images from a cohort population. The subjects were 561 patients aged 30-79 years from the Kanagawa Knee Study who had not visited a hospital for more than three consecutive months for knee symptoms. MR images of the PF joints, separated into the medial and lateral types, were presented in order of the highest to lowest patella cartilage area ratios. Cartilage defects in the patella were detected in 37 subjects (6.6%). Medial lesions (4.6%) were significantly more frequent than lateral lesions (2.0%) (p < 0.01). For both medial and lateral lesions, the patellar cartilage defects were divided into confined and unconfined types. The 3D MR images of the PF joint showed that the patellar cartilage defect occurred along each ridge of the femoral trochlea. The 3D MR images revealed a 6.6% prevalence of patellar cartilage defects, higher in the medial than lateral regions. The 3D MR images can easily determine PF morphology and cartilage defect location, making them useful in understanding the pathophysiology and etiology of PFOA.

Which risk factors determine cartilage thickness and composition change in radiographically normal knees? - Data from the Osteoarthritis Initiative

Objective

Therapy for osteoarthritis ideally aims at preserving structure before radiographic change occurs. This study tests: a) whether longitudinal deterioration in cartilage thickness and composition (transverse relaxation-time T2) are greater in radiographically normal knees "at risk" of incident osteoarthritis than in those without risk factors; and b) which risk factors may be associated with these deteriorations.

Design

755 knees from the Osteoarthritis Initiative were studied; all were bilaterally Kellgren Lawrence grade [KLG] 0 initially, and had magnetic resonance images available at 12- and 48-month follow-up. 678 knees were "at risk", whereas 77 were not (i.e., non-exposed reference). Cartilage thickness and composition change was determined in 16 femorotibial subregions, with deep and superficial T2 being analyzed in a subset (n ​= ​59/52). Subregion values were used to compute location-independent change scores.

Results

In KLG0 knees "at risk", the femorotibial cartilage thinning score (-634 ​± ​516 ​μm) over 3 years exceeded the thickening score by approximately 20%, and was 27% greater (p ​< ​0.01; Cohen D -0.27) than the thinning score in "non-exposed" knees (-501 ​± ​319 ​μm). Superficial and deep cartilage T2 change, however, did not differ significantly between both groups (p ​≥ ​0.38). Age, sex, body mass index, knee trauma/surgery history, family history of joint replacement, presence of Heberden's nodes, repetitive knee bending were not significantly associated with cartilage thinning (r²<1%), with only knee pain reaching statistical significance.

Conclusions

Knees "at risk" of incident knee OA displayed greater cartilage thinning scores than those "non-exposed". Except for knee pain, the greater cartilage loss was not significantly associated with demographic or clinical risk factors.

Lower bone mineral density can be a risk for an enlarging bone marrow lesion: A longitudinal cohort study of Japanese women without radiographic knee osteoarthritis

OBJECTIVES

The aim is to elucidate the relationship between bone mineral density (BMD) at baseline and the change of bone marrow lesion (BML) during a 2-year follow-up (2YFU) period.

METHODS

Seventy-eight female participants (mean age: 54.9 ± 9.6 years) without radiographic knee osteoarthritis were eligible. Based on right-knee magnetic resonance imaging, maximum BML area (BMLa) was calculated by tracing the BML border. The change in BMLa was defined using the following formula: [2YFU] - [Baseline] = ΔBMLa. Positive ΔBMLa was defined as enlarged; negative ΔBMLa was defined as regressed. Dual-energy X-ray absorptiometry was performed to measure the BMD of distal radius. Young adult mean [YAM (%)] of the BMD was used for statistical analysis. Linear regression analysis was conducted with ΔBMLa as the dependent variable and YAM as the independent variable. Receiver operating characteristic curve and logistic regression analyses were conducted for YAM to predict the prevalence of BML enlargement or regression.

RESULTS

Twenty-six (33.3%) patients had enlarged BMLa, 12 (15.4%) participants showed regressing BMLa, and 40 (51.3%) patients remained stable. YAM was negatively associated with ΔBMLa (β: - 0.375, P = 0.046). The best predictor of BML enlargement risk was 85% (odds ratio: 8.383, P = 0.025).

CONCLUSIONS

Lower BMD could predict BML enlargement during a 2YFU period.

Association between baseline meniscal extrusion and long-term incident knee osteoarthritis in two different cohorts

OBJECTIVE

Previously, we identified a significant association between meniscal extrusion and short-term incident knee osteoarthritis (KOA). To validate these findings, we evaluated long-term incident KOA in knees with meniscus extrusion, using two different cohorts.

METHODS

We used data from the PROOF study, which evaluated a high-risk population of overweight women, and a female subcohort of the population-based Rotterdam Study (RS). Meniscal extrusion was defined as ≥ 3 mm on MRI. Outcomes were incident radiographic (KL ≥ 2) or clinical KOA according to the ACR criteria, assessed at 6.6 years (PROOF) and 5.1 years (RS). With generalized estimating equations, we determined the association of knees with and without baseline meniscal extrusion and incident KOA, adjusting for confounders. Furthermore, we computed the population attributable risk percentage (PAR%) of meniscal extrusion.

RESULTS

PROOF: of 421 available knees 23% had baseline meniscal extrusion. Incident radiographic KOA was significantly higher in knees with meniscal extrusion compared to those without (adjusted OR 2.54, 95% CI 1.34, 4.80; p = 0.004; PAR 21%). Incident clinical KOA was also significantly higher (adjusted OR 2.44, 95% CI 1.29, 4.60; p = 0.006; PAR 19%). RS: 46% of 872 available knees had meniscal extrusion. Incident radiographic KOA was significantly higher (adjusted OR 9.86, 95% CI 2.13, 45.67; p = 0.002; PAR 77%). Incident clinical KOA was borderline significantly higher (adjusted OR 2.65, 95% CI 0.96, 7.30; p = 0.06; PAR 44%).

CONCLUSION

Meniscal extrusion is significantly associated with long-term incident KOA. A high number of incident cases were attributable to extrusion.

Inflammaging and Osteoarthritis

Osteoarthritis is a highly prevalent disease particularly in subjects over 65 years of age worldwide. While in the past it was considered a mere consequence of cartilage degradation leading to anatomical and functional joint impairment, in recent decades, there has been a more dynamic view with the synovium, the cartilage, and the subchondral bone producing inflammatory mediators which ultimately lead to cartilage damage. Inflammaging is defined as a chronic, sterile, low-grade inflammation state driven by endogenous signals in the absence of infections, occurring with aging. This chronic status is linked to the production of reactive oxygen species and molecules involved in the development of age-related disease such as cancer, diabetes, and cardiovascular and neurodegenerative diseases. Inflammaging contributes to osteoarthritis development where both the innate and the adaptive immune response are involved. Elevated systemic and local inflammatory cytokines and senescent molecules promote cartilage degradation, and antigens derived from damaged joints further trigger inflammation through inflammasome activation. B and T lymphocyte populations also change with inflammaging and OA, with reduced regulatory functions, thus implicating self-reactivity as an additional mechanism of joint damage. The discovery of the underlying pathogenic pathways may help to identify potential therapeutic targets for the management or the prevention of osteoarthritis. We will provide a comprehensive evaluation of the current literature on the role of inflammaging in osteoarthritis and discuss the emerging therapeutic strategies.

Personalized Risk Model and Leveraging of Magnetic Resonance Imaging-Based Structural Phenotypes and Clinical Factors to Predict Incidence of Radiographic Osteoarthritis

OBJECTIVE

Our study aimed to investigate the association between time to incidence of radiographic osteoarthritis (OA) and magnetic resonance imaging (MRI)-based structural phenotypes proposed by the Rapid Osteoarthritis MRI Eligibility Score (ROAMES).

METHODS

A retrospective cohort of 2,328 participants without radiographic OA at baseline were selected from the Osteoarthritis Initiative study. Utilizing a deep-learning model, we automatically assessed the presence of inflammatory, meniscus/cartilage, subchondral bone, and hypertrophic phenotypes from MRIs acquired at baseline and 12-, 24-, 36-, 48-, 72-, and 96-month follow-up visits. In addition to 4 structural phenotypes, we examined severe knee injury history and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scores as time dependent. We used Cox proportional hazards regression to analyze the association between 4 structural phenotypes and radiographic OA disease-free survival, both univariate and adjusted for known risk factors including age, sex, race, body mass index, presence of Heberden's nodes, and knee malalignment.

RESULTS

Inflammatory (hazard ratio [HR] 3.37 [95% confidence interval (95% CI) 2.45-4.63]), meniscus/cartilage (HR 1.55 [95% CI 1.21-1.98]), and subchondral bone (HR 1.84 [95% CI 1.63-2.09]) phenotypes were associated with time to radiographic OA at P < 0.05 when adjusted for the risk factors. Sex was a modifier of hypertrophic phenotype association with time to radiographic OA. Female participants with the hypertrophic phenotype were associated with 2.8 times higher risk of radiographic OA (95% CI 2.25-7.54) compared to male participants without the hypertrophic phenotype.

CONCLUSION

Four ROAMES phenotypes may contribute to time to radiographic OA incidence and if validated could be used as a promising tool for personalized OA management.

Early knee OA definition-what do we know at this stage? An imaging perspective

While criteria for early-stage knee osteoarthritis (OA) in a primary care setting have been proposed, the role of imaging has been limited to radiography using the standard Kellgren-Lawrence classification. Standardized imaging and interpretation are critical with radiographs, yet studies have also shown that even early stages of radiographic OA already demonstrate advanced damage to knee joint tissues such as cartilage, menisci, and bone marrow. Morphological magnetic resonance imaging (MRI) shows degenerative damage earlier than radiographs and definitions for OA using MRI have been published though no accepted definition of early OA based on MRI is currently available. The clinical significance of structural abnormalities has also not been well defined, and the differentiation between normal aging and structural OA development remains a challenge. Compositional MRI of cartilage provides information on biochemical, degenerative changes within the cartilage matrix before cartilage defects occur and when cartilage damage is potentially reversible. Studies have shown that cartilage composition can predict cartilage loss and radiographic OA. However, while this technology is most promising for characterizing early OA it has currently limited clinical application. Better standardization of compositional MRI is required, which is currently work in progress. Finally, there has been renewed interest in computed tomography (CT) for assessing early knee OA as new techniques such as weight bearing and spectral CT are available, which may provide information on joint loading, cartilage, and bone and potentially have a role in better characterizing early OA. In conclusion, while imaging may have a limited role in diagnosing early OA in a primary care setting, there are advanced imaging technologies available, which detect early degeneration and may thus significantly alter management as new therapeutic modalities evolve.

The relationship between meniscal pathologies, cartilage loss, joint replacement and pain in knee osteoarthritis: a systematic review

OBJECTIVE

We conducted a systematic review in order to understand the relationship between imaging-visualised meniscus pathologies, hyaline cartilage, joint replacement and pain in knee osteoarthritis (OA).

DESIGN

A search of the Medline, Excerpta Medica database (EMBASE) and Cochrane library databases was performed for original publications reporting association between imaging-detected meniscal pathology (extrusion or tear/damage) and longitudinal and cross-sectional assessments of hyaline articular cartilage loss [assessed on magnetic resonance imaging (MRI)], incident joint replacement and pain (longitudinal and cross-sectional) in knee OA. Each association was qualitatively characterised by a synthesis of data from each analysis, based upon study design and quality scoring (including risk of bias assessment and adequacy of covariate adjustment using Cochrane recommended methodology).

RESULTS

In total 4,878 abstracts were screened and 82 publications were included (comprising 72 longitudinal analyses and 49 cross-sectional). Using high quality, well-adjusted data, meniscal extrusion and meniscal tear/damage were associated with longitudinal progression of cartilage loss, cross-sectional cartilage loss severity and joint replacement, independently of age, sex and body mass index (BMI). Medial and lateral meniscal tears were associated with cartilage loss when they occurred in the body and posterior horns, but not the anterior horns. There was a lack of high quality, well-adjusted meniscal pathology and pain publications and no clear independent association between meniscal extrusion or tear/damage with pain severity, progression in pain or incident frequent knee symptoms.

CONCLUSION

Meniscal features have strong associations with cartilage loss and joint replacement in knee OA, but weak associations with knee pain. Systematic review PROSPERO registration number: CRD 42020210910.

Biomechanical analysis of a centralization procedure for extruded lateral meniscus after meniscectomy in porcine knee joints

The recently developed arthroscopic centralization for lateral meniscal extrusion has obtained satisfactory short-term clinical and radiological results and improves the meniscus biomechanical properties. However, the effectiveness of treatment for meniscus extrusion after partial meniscectomy still requires elucidation. This study investigated the effect of centralization with modifications from a mechanical viewpoint. Porcine knee joints (N = 6) were set in a universal tester under the following conditions: (1) Intact; (2) Meniscectomy: Inner half of the posterior half meniscus was removed; (3) Extrusion: Posterior meniscus was dislocated laterally by transecting the posterior root and the meniscotibial ligament; (4) Centralization-1: Centralization procedure using one anchor; (5) Centralization-2: Centralization procedure using two anchors; and (6) Centralization-ad: Centralization with capsular advancement using two anchors. Load distributions and contact pressure in the meniscus and tibial cartilage were evaluated with an axial compressive force of 200 N. After meniscectomy, the tibial cartilage load increased and that of the medial margin of the posterior part of the meniscus decreased. When the meniscus was extruded, the load was concentrated only on the tibial cartilage. Centralization-1 increased the load on the meniscus, while Centralization-2 further increased the meniscus load but decreased the tibial cartilage load. Centralization-ad further decreased the load on the tibial plateau. The average contact pressure of the tibial cartilage was significantly higher in the Extrusion group than in the Intact group or the Centralization-ad group. From a biomechanical viewpoint, centralization with capsular advancement was the most effective of the tested procedures for treatment for an extruded meniscus after partial meniscectomy.

A narrative review of lateral meniscus root tears and extrusion: techniques and outcomes

Objective

In this review, we performed a literature search and described the surgical procedure for a lateral meniscus posterior root tears (LMPRT) repair using a pull-out technique and an arthroscopic centralization for lateral meniscus (LM) extrusion.

Background

The menisci play a pivotal role in the shock-absorbing and load-dispersing functions of the knee joint. They also contribute to its stability. Meniscal root tears substantially affect meniscal hoop function and accelerate cartilage degeneration. Additionally, LMPRT have been shown to affect anterolateral knee laxity and tibiofemoral contact pressure in knees with anterior cruciate ligament (ACL) injury. Therefore, appropriate management of LMPRT is essential for restoring knee function. Meniscus extrusion has attracted attention due to its association with early osteoarthritis (OA). Recently, an arthroscopic centralization technique has been proposed to reduce meniscal extrusion. During this procedure the capsule attached to the meniscus is sutured to the edge of the tibial plateau using suture anchors.

Methods

A narrative review of LMPRT repair and arthroscopic centralization of lateral meniscal extrusion was performed through a PubMed search.

Conclusions

Specific magnetic resonance imaging (MRI) signs were useful for the diagnosis of LMPRT. Pull-out techniques can restore knee stability and load distribution function and result in favorable clinical outcomes. Arthroscopic centralization of the extruded LM caused by meniscectomy and lateral discoid meniscus achieved satisfactory clinical outcomes at the 2-year follow-up. Biomechanical studies demonstrated that this procedure reduced meniscus extrusion and had beneficial effects on load distribution and joint stability. In summary, to restore knee function, LMPRT should be repaired as much as possible. The centralization technique is a promising surgical treatment for extruded lateral menisci due to meniscectomy and discoid meniscus. However, due to the lack of high-level evidence studies such as randomized control trials (RCTs) in this field, it remains necessary to accumulate evidence to confirm the efficacy of LMPRT repair and the centralization technique.

Infrapatellar fat pad volume and Hoffa-synovitis after ACL reconstruction: Association with early osteoarthritis features and pain over 5 years

Infrapatellar fat pad (IPFP) morphology and Hoffa-synovitis may be relevant to the development and progression of post-traumatic osteoarthritis (OA). We aimed to compare IPFP volume and Hoffa-synovitis in participants with anterior cruciate ligament reconstruction (ACLR) and uninjured controls, and to determine their association with prevalent and worsening early knee OA features and pain in participants post-ACLR. We assessed IPFP volume and Hoffa-synovitis from magnetic resonance imaging (MRI) in 111 participants 1-year post-ACLR and 20 uninjured controls. Patellofemoral and tibiofemoral cartilage and bone marrow lesions (BMLs) were assessed from MRIs at 1 and 5 years post-ACLR, and worsening defined as any longitudinal increase in lesion size/severity. IPFP volume and Hoffa-synovitis prevalence were compared between groups with analysis of covariance and χ ² tests, respectively. Generalized linear models assessed the relation of IPFP volume and Hoffa-synovitis to prevalent and worsening features of OA and knee pain (Knee injury and Osteoarthritis Outcome Score-Pain Subscale, Anterior Knee Pain Scale). No significant between-group differences were observed in IPFP volume (ACLR 34.39 ± 7.29cm³ , Control 34.27 ± 7.56cm³ ) and Hoffa-synovitis (ACLR 61%, Control 80%). Greater IPFP volume at 1-year post-ACLR was associated with greater odds of patellofemoral BMLs at 1-year (odds ratio [OR] [95% confidence intervals]: 1.104 [1.016, 1.200]) and worsening tibiofemoral cartilage lesions at 5-year post-ACLR (OR: 1.234 [1.026, 1.483]). Hoffa-synovitis at 1-year post-ACLR was associated with greater odds of worsening patellofemoral BMLs at 5-year post-ACLR (OR: 7.465 [1.291, 43.169]). In conclusion, IPFP volume and Hoffa-synovitis prevalence are similar between individuals 1-year post-ACLR and controls. Greater IPFP volume and Hoffa-synovitis appear to be associated with the presence and worsening of some early OA features in those post-ACLR, but not pain.

Is Laminar Cartilage Composition as Determined by T2 Relaxometry Associated with Incident and Worsening of Cartilage or Bone Marrow Abnormalities?

OBJECTIVE

To test the hypothesis that superficial cartilage composition (T2) is associated with subsequent incidence or worsening of cartilage damage, and deep T2 with that of bone marrow lesions (BMLs) in knees without radiographic osteoarthritis (ROA).

DESIGN

A total of 201 knees from the Osteoarthritis Initiative without ROA were included: 78 from the healthy reference cohort, 60 without ROA but with risk factors, and 63 without ROA but with contralateral ROA. Year 1 (Y1) superficial and deep cartilage T2 were derived in the medial and lateral (weightbearing) femur (MF/LF) and tibia (MT/LT), using sagittal multiecho spin echo magnetic resonance images. Cartilage and BMLs were assessed in the medial (MFTJ) and lateral femorotibial joint (LFTJ) at Y1 and 3 years later. Binary logistic regression statistics were applied.

RESULTS

Incidence or worsening of cartilage damage was more frequent (MFTJ 15%, LFTJ 13%) than incidence or worsening of BMLs (6.0%, 4.5%). In knees with incident or worsening cartilage lesions in the MF and LT, deep layer T2 in the same plate was elevated (MF, 43.6 ± 4.0 vs. 41.3 ± 3.8 ms, P = 0.047; LT, 33.8 ± 2.3 vs. 32.0 ± 2.2 ms, P = 0.008) compared to those without. In knees with incident or worsening of BMLs in the LFTC and LT, superficial layer T2 was elevated (LFTJ, 49.6 ± 4.8 vs. 46.7 ± 3.1 ms; LT, 47.4 ± 4.9 vs. 44.0 ± 3.3 ms, both Ps = 0.04).

CONCLUSIONS

Contrary to our hypothesis, increased deep layer cartilage T2 was associated with subsequent worsening of cartilage damage, whereas superficial layer T2 was related to subsequent BML worsening. Yet, this relationship was observed in some, but not in all cartilage plates.

Common Biochemical and Magnetic Resonance Imaging Biomarkers of Early Knee Osteoarthritis and of Exercise/Training in Athletes: A Narrative Review

Knee osteoarthritis (OA) is the most common joint disease of the world population. Although considered a disease of old age, OA also affects young individuals and, more specifically among them, those practicing knee-joint-loading sports. Predicting OA at an early stage is crucial but remains a challenge. Biomarkers that can predict early OA development will help in the design of specific therapeutic strategies for individuals and, for athletes, to avoid adverse outcomes due to exercising/training regimens. This review summarizes and compares the current knowledge of fluid and magnetic resonance imaging (MRI) biomarkers common to early knee OA and exercise/training in athletes. A variety of fluid biochemical markers have been proposed to detect knee OA at an early stage; however, few have shown similar behavior between the two studied groups. Moreover, in endurance athletes, they are often contingent on the sport involved. MRI has also demonstrated its ability for early detection of joint structural alterations in both groups. It is currently suggested that for optimal forecasting of early knee structural alterations, both fluid and MRI biomarkers should be analyzed as a panel and/or combined, rather than individually.

Effects of anterior cruciate ligament reconstruction on patellofemoral joint stress and lower extremity biomechanics at 12 weeks post-surgery and at time of return to sport in adolescent females

BACKGROUND

The purpose of this study was to examine kinematic and kinetic differences associated with patellofemoral pain after anterior cruciate ligament reconstruction between limbs at 12-week post-surgery and at time of return to sport.

METHOD

Twenty-four adolescent females completed 5 consecutive single leg squats on each limb at 12-weeks post-surgery and again during their RTS assessment. Peak knee extension moment, peak hip adduction angle, and patellofemoral joint stress at 45 degrees of knee flexion were calculated. Separate two by two repeated measures ANOVA were performed.

FINDINGS

There was a significant interaction (limb × time) for knee extension moment (p < 0.001). Surgical limb knee extension moment was significantly less than the non-surgical limb at return to sport (p < 0.001). At 12-weeks the surgical limb was significantly less than non-surgical limb (p < 0.001), additionally the surgical limb was significantly greater at time of return to sport than at 12 weeks (p < 0.001). There was a significant main effect of limb for hip adduction angle (p = 0.002). Surgical limb was significantly greater than non-surgical limb (Surgical = 9.84 (SE 1.53) degree, non-surgical = 4.79 (SE 1.01) degree). There was also a main effect of time and limb for patellofemoral joint stress. Return to sport was significantly greater than 12 weeks and the surgical limb was significantly less than non-surgical limb (Surgical = 4.93 (SE 0325) MPa, Nonsurgical = 5.29 (SE 0.30) MPa).

INTERPRETATION

The surgical limb of participants following ACL-R demonstrated variables that have been associated with the development of patellofemoral pain.

Pathophysiological Perspective of Osteoarthritis

Osteoarthritis (OA) is the most well-known degenerative disease among the geriatric and is a main cause of significant disability in daily living. It has a multifactorial etiology and is characterized by pathological changes in the knee joint structure including cartilage erosion, synovial inflammation, and subchondral sclerosis with osteophyte formation. To date, no efficient treatment is capable of altering the pathological progression of OA, and current therapy is broadly divided into pharmacological and nonpharmacological measures prior to surgical intervention. In this review, the significant risk factors and mediators, such as cytokines, proteolytic enzymes, and nitric oxide, that trigger the loss of the normal homeostasis and structural changes in the articular cartilage during the progression of OA are described. As the understanding of the mechanisms underlying OA improves, treatments are being developed that target specific mediators thought to promote the cartilage destruction that results from imbalanced catabolic and anabolic activity in the joint.

Association of Long-term Strenuous Physical Activity and Extensive Sitting With Incident Radiographic Knee Osteoarthritis

IMPORTANCE

Persons with knee symptoms recognize the health benefits of engaging in physical activity, but uncertainty persists about whether regular strenuous physical activity or exercise can accelerate tissue damage. A sedentary lifestyle of inactivity or underloading may also be associated with deleterious joint health.

OBJECTIVE

To establish whether long-term strenuous physical activity participation and extensive sitting behavior are each associated with increased risk of developing radiographic knee osteoarthritis (KOA) in individuals at high risk for the disease.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed data from the Osteoarthritis Initiative, a prospective longitudinal cohort study of men and women with or at an increased risk of developing symptomatic, radiographic KOA. Community-dwelling adults were recruited from 4 US sites (Baltimore, Maryland; Columbus, Ohio; Pittsburgh, Pennsylvania; and Pawtucket, Rhode Island) and were followed up for up to 10 years. Individuals were included if they had a baseline Kellgren and Lawrence grade of 0 in both knees and completed a PASE (Physical Activity Scale for the Elderly) questionnaire at baseline and at least 2 follow-up visits over an 8-year interval. Data analyses were conducted from May 2018 to November 2018.

EXPOSURES

Baseline to 8-year trajectories of strenuous physical activity participation and extensive sitting behavior were identified using group-based trajectory models.

MAIN OUTCOMES AND MEASURES

Incident radiographic KOA, defined as Kellgren and Lawrence grade 2 or higher in either knee by the 10-year follow-up visit.

RESULTS

A total of 1194 participants were included in the sample (697 women [58.4%]), with a baseline mean (SD) age of 58.4 (8.9) years and mean body mass index (BMI) of 26.8 (4.5). Four distinct trajectories of weekly hours spent in strenuous physical activities and 3 distinct trajectories of extensive sitting were identified. Long-term engagement in low-to-moderate physical activities (adjusted odds ratio [OR], 0.69; 95% CI, 0.48-1.01) or any strenuous physical activities (adjusted OR, 0.75; 95% CI, 0.53-1.07) was not associated with 10-year incident radiographic KOA. Persistent extensive sitting was not associated with incident KOA. Despite relatively mild symptoms and high function in this early-stage sample, 594 participants (49.7%) did not engage in any strenuous physical activities (ie, 0 h/wk) across 8 years, and 507 (42.5%) engaged in persistent moderate-to-high frequency of extensive sitting. Older age, higher BMI, more severe knee pain, non-college graduate educational level, weaker quadriceps, and depression were each associated with a persistent lack of engagement in strenuous physical activities.

CONCLUSIONS AND RELEVANCE

Results from this study appeared to show no association between long-term strenuous physical activity participation and incident radiographic KOA. The findings raise the possibility of a protective association between incident KOA and a low-to-moderate level of strenuous physical activities.

The effect of a centralization procedure for extruded lateral meniscus on load distribution in porcine knee joints at different flexion angles

Background

Meniscal extrusion results in loss of the ability to resist hoop strain and biomechanical overload on the joint articular surface. A centralization technique has been developed to overcome these problems. In this study, we analyzed the biomechanics of the extruded and centralized lateral meniscus (LM) in porcine knee joints at different flexion angles.

Methods

Porcine knee joints (n = 8) were set in the universal tester and each knee was tested under the following states: 1) intact; 2) extrusion—meniscal extrusion was created by resecting the posterior root of the LM and posterior synovial capsule; and 3) centralization—centralization was performed by two anchors inserted in the lateral tibial plateau. Deviation distance of the meniscus, contact pressure, and contact area in the anterior LM, middle LM, posterior LM, and the contact pressure of the tibial cartilage were evaluated with an axial compressive force of 200 N at knee flexion angles of 30°, 45°, 60°, and 90°.

Results

The deviation distance of LM significantly increased in extrusion but was restored to the intact status after centralization at all angles. Both the contact pressure and area significantly decreased in extrusion and were restored after centralization close to the intact status in the anterior and middle LM; in the posterior LM, however, decreased contact pressure and area were not restored after centralization. The contact pressure of the tibial cartilage increased significantly in extrusion but decreased close to the intact status after centralization.

Conclusions

This centralization procedure could reduce extrusion of the LM and restore the load-distributing function of the anterior-middle LM. However, the procedure itself could not restore hoop function in cases where the defect lies in the posterior LM.

US detection of medial meniscus extrusion can predict the risk of developing radiographic knee osteoarthritis: a 5-year cohort study

OBJECTIVES

To clarify the relationship between the baseline value of medial meniscus extrusion (MME) and the radiographic change of knee osteoarthritis (KOA) through a 5-year follow-up.

METHODS

Overall, 472 participants and 944 knees were eligible. MME (mm) was measured at the baseline, and KOA was radiographically evaluated at both baseline and 5-year follow-up by Kellgren-Lawrence grade (KLG). Radiographic KOA (ROA) was defined as the knee showing KLG ≥ 2. Incident ROA (iROA) was defined if the baseline KLG of 0-1 increased to KLG ≥ 2 in 5 years. Progressive ROA (pROA) was defined if the baseline KLG of 2-3 worsened to a higher grade in 5 years. Receiver operating characteristic (ROC) curve and generalized estimating equations were used for analysis.

RESULTS

Of 574 non-ROA knees at the baseline, 43 knees (7.5%) developed iROA; of 370 ROA knees, 47 knees (12.7%) developed pROA. Based on the ROC curves, 4 mm was the optimal cutoff to detect the risk of iROA (area under curve [AUC] 0.639 [right knee]; AUC 0.641 [left knee]) and that of pROA (AUC 0.750 [right knee]; AUC 0.863 [left knee]). Multiple regression analysis showed that the 4-mm cutoff of MME was significantly associated with both the prevalence of iROA (regression coefficient [B] 1.909; p ≤ 0.001; adjusted odds ratio [aOR] 6.746) and that of pROA (B 1.791; p ≤ 0.001; aOR 5.993).

CONCLUSIONS

On ultrasonography, the participants with more extruded medial meniscus showed a higher prevalence of both iROA and pROA. Ultrasonography could identify patients who had a risk of developing KOA.

KEY POINTS

• Through a 5-year follow-up, the current cohort study was conducted to clarify the relationship between the baseline value of medial meniscus extrusion (MME) and the radiographic change of knee osteoarthritis (KOA). • More extruded medial meniscus evaluated by ultrasonography was associated with the development of radiographic KOA. • Ultrasonography could identify the patients who had a risk of developing KOA, and the 4-mm cutoff of MME was optimal to detect this risk.

Biomechanical analysis of the centralization procedure for extruded lateral menisci with posterior root deficiency in a porcine model

PURPOSE

The purpose of this study was to investigate the biomechanical properties of load distribution following a centralization procedure for extruded lateral menisci with posterior root deficiency in a porcine model.

METHODS

Six porcine knee joints were analyzed in a universal tester, as follows: 1) Intact; 2) Extrusion (meniscus extrusion was created by resecting the posterior root of the lateral meniscus, as well as the posterior synovial capsule); and 3) Centralization (two anchors were inserted at the lateral tibial plateau, and the meniscus was sutured to secure it close to the original position). Meniscus extrusion was evaluated using two markers put on the posterior cruciate ligament and the lateral meniscus, and the load distribution were assessed using a pressure mapping sensor system after applying a loading force of 200 N to the knee joint.

RESULTS

Distance between two markers (mm, Average; 95% CI) was larger in the extrusion group (21.9; 17.8, 25.6) than in the intact (18.1; 15.1, 22.7) or the centralization (15.3; 12.9, 18.0) groups. The contact area (mm²) in the middle of the meniscus was significantly smaller in the extrusion group (45.8; 18.5, 73.2) than in the intact (85.7; 72.1, 99.2) or the centralization (98.3; 88.8, 107.8) groups. The maximum contact pressure (MPa) in the tibial plateau was significantly higher in the extrusion group (0.37; 0.35, 0.40) than in the intact (0.29; 0.21, 0.37) or the centralization (0.29; 0.22, 0.36) groups.

CONCLUSIONS

The centralization procedure enabled a reduction of the meniscus extrusion in the lateral meniscus with posterior root deficiency and restored the maximum load and contact pressure to values close to those of the normal knee joint.

Efficacy of magnetic resonance imaging with an SPGR sequence for the early evaluation of knee cartilage degeneration and the relationship between cartilage and other tissues

Rationale and objectives

The aim of this study was to investigate the efficacy of magnetic resonance imaging (MRI) with a spoiled gradient-recalled (SPGR) sequence to evaluate early knee cartilage degeneration and the relationship between cartilage and other tissues using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS).

Materials and methods

Eighty-four patients with knee joint pain were evaluated by X-ray and MRI with an SPGR sequence from June 2015 to December 2016. Joint degeneration was graded by two experienced radiologists using the Kellgren-Lawrence (K-L) grading scale. The modified WORMS was used to evaluate cartilage lesions, bone marrow abnormalities, bone cysts, osteophytes, joint effusion and synovitis. The difference between the WORMS of the SPGR and the T2 sequences evaluated by the Wilcoxon signed-rank test was determined, and the relationships between the WORMS features were evaluated by a Spearman correlation.

Results

The modified WORMS for the cartilage lesion evaluation was significantly higher with the SPGR sequence than with the T2 sequence (P < 0.05). The cartilage lesions showed a moderate correlation with osteophytes, synovitis and joint effusion (Rs > 0.40, P < 0.05) and weak correlations with bone marrow abnormalities and bone cysts (Rs < 0.4, P < 0.05).

Conclusion

The modified WORMS evaluation using MRI with the SPGR sequence was much better than the normal sequence for early knee osteoarthritis (OA). The cartilage lesions are associated with bone marrow abnormalities and the other features of OA.

Accelerated Knee Osteoarthritis Is Characterized by Destabilizing Meniscal Tears and Preradiographic Structural Disease Burden

OBJECTIVE

To determine whether accelerated knee osteoarthritis (KOA) is preceded by, and characterized over time by, destabilizing meniscal tears or other pathologic changes.

METHODS

We selected 3 sex-matched groups of subjects from the first 48 months of the Osteoarthritis Initiative, comprising adults who had a knee without KOA (Kellgren/Lawrence [K/L] radiographic grade <2) at baseline. Subjects in the accelerated KOA group developed KOA of K/L grade ≥3, those with typical KOA showed increased K/L radiographic scores, and those with no KOA had the same K/L grade over time. An index visit was the visit when the radiographic criteria for accelerated KOA and typical KOA were met (the no KOA group was matched to the accelerated KOA group). The observation period was up to 2 years before and after an index visit. Radiologists reviewed magnetic resonance (MR) images of the index knee and identified destabilizing meniscal tears (root tears, radial tears, complex tears), miscellaneous pathologic features (acute ligamentous or tendinous injuries, attrition, subchondral insufficiency fractures, other incidental findings), and meniscal damage in >2 of 6 regions (3 regions per meniscus: anterior horn, body, posterior horn). In addition, bone marrow lesions (BMLs) and cartilage damage on MR images were quantified. Linear mixed regression models were performed to analyze the results.

RESULTS

At 1 year before the index visit, >75% of adults with accelerated KOA had meniscal damage in ≥2 regions (odds ratio 3.19 [95% confidence interval 1.70-5.97] versus adults with typical KOA). By the index visit, meniscal damage in ≥2 regions was ubiquitous in adults with accelerated KOA, including 42% of subjects having evidence of a destabilizing meniscal tear (versus 14% of subjects with typical KOA). These changes corresponded to findings of larger BMLs and greater cartilage loss in the accelerated KOA group.

CONCLUSION

Accelerated KOA is characterized by destabilizing meniscal tears in a knee compromised by meniscal damage in >2 regions, and also characterized by the presence of large BMLs and greater cartilage loss.

Bone marrow lesion is associated with disability for activities of daily living in patients with early stage knee osteoarthritis

Osteoarthritis of the knee (knee OA) induces pain, loss of mobility and diminished activities of daily living (ADL). Although an understanding of the pathophysiology of early stage knee OA has been developed, the structural changes associated with disability for ADL in early stage knee OA are still unclear. The aim of the present study was to examine magnetic resonance imaging (MRI)-detected changes associated with disability for ADL in patients with early stage knee OA. One hundred and thirty-two patients with early stage medial knee OA (Kellgren-Lawrence grade ≤ 2) who first visited the outpatient clinic at our university hospital were included. They were also examined by 3.0-Tesla knee MRI. The OA-associated structural changes were scored using the Whole-Organ Magnetic Resonance Imaging Score (WORMS), and clinical manifestations were evaluated by the Japanese Knee Osteoarthritis Measure (JKOM). Median quartile regression was used for the analysis. Cartilage lesion, subchondral bone attrition and osteophytes were observed in all patients. Bone marrow lesions (BMLs) and synovitis were observed in 60% and 55% of the patients, respectively. Subchondral cysts and ligament changes were observed in 6% and 17% of the patients, respectively. Pain severity of the patients was associated with medial cartilage lesions (coefficient 2.50, 95% confidence interval 0.61-4.40, p < 0.01). Disability for ADL of the patients was associated with BMLs in the medial side of the knee joint (0.82, 0.21-1.02, p = 0.04). BMLs in the medial side of the knee joint were associated with disability for ADL of patients with early stage medial knee OA.

Cartilage loss in radiographically normal knees depends on radiographic status of the contralateral knee - data from the Osteoarthritis Initiative

OBJECTIVE

To test whether radiographically normal knees with contralateral radiographic knee osteoarthritis (OA), but without contralateral trauma history, display greater cartilage thickness loss than knees from subjects with bilaterally radiographically normal knees.

METHODS

828 radiographically normal knees (Kellgren Lawrence grade [KLG] 0) from the Osteoarthritis Initiative [OAI] were studied; 150 case knees displayed definite radiographic knee OA (KLG ≥ 2) contralaterally, and had MRI double echo steady state (DESS) images available at 12 and 48 month follow-up. 678 reference knees displayed KLG0 at the contralateral side. Cartilage thickness change was determined in femorotibial subregions and location-independent cartilage thinning scores were computed. Case and reference knees were compared using ANCOVA.

RESULTS

Of the 150 KLG0 case knees, 108 had a contralateral KLG2 knee (50 without, and 58 with joint space narrowing [JSN]), 31 a KLG3 and 11 a KLG4 knee. The cartilage thinning score tended to be greater in case than reference knees; the cartilage thinning score in KLG0 case knees with contralateral radiographic JSN (-858 μm; [95% confidence interval -1016, -701 μm]) was significantly greater (P = 0.0012) than that in bilaterally KLG0 reference knees (-634 μm; [-673, -596 μm]), whereas KLG0 knees with contralateral KLG2 without JSN only showed relatively small thinning scores (-530 μm, [-631, -428 μm]). Region-specific analysis suggested greater rates of cartilage loss in case than in reference knees in the lateral, rather than medial, femorotibial compartment.

CONCLUSIONS

Radiographically normal knees with contralateral JSN may serve as a human model of early OA, for testing disease modifying drugs in clinical trials designed to prevent cartilage loss before the onset of radiographic change. CLINICALTRIALS.

GOV IDENTIFICATION

NCT00080171.

Effect of weight change on progression of knee OA structural features assessed by MRI in overweight and obese women

OBJECTIVE

To evaluate the effects of weight change on progression of knee osteoarthritis (OA) structural features by magnetic resonance imaging (MRI) in overweight and obese women without clinical knee OA.

DESIGN

347 participants from the Prevention of Knee Osteoarthritis in Overweight Females (PROOF) study were classified with latent class growth analysis into a subgroup with steady weight (n = 260; +0.1 ± 4.0 kg, +0.2 ± 4.4%), weight gain (n = 43; +8.6 ± 4.0 kg, +9.8 ± 4.1%) or weight loss (n = 44; -9.0 ± 7.2 kg, -9.8 ± 7.5%) over 2.5 years. Baseline and follow-up 1.5T MRIs were scored with MRI Osteoarthritis Knee Score (MOAKS) for progression of bone marrow lesions (BMLs), cartilage defects, osteophytes, meniscal abnormalities, meniscal extrusion and synovitis. Associations between subgroups and change in MRI features at knee-level were assessed using adjusted Generalized Estimating Equations.

RESULTS

687 knees from 347 women (median age 55.2 years, interquartile range (IQR) 5.5, median body mass index (BMI) 31.2 kg/m², IQR 5.3) were analyzed. Progression of synovitis was 18% in the weight gain vs 7% in the stable weight subgroup (OR 2.88; 95%CI 1.39-5.94). The odds for progression of patellofemoral (PF) BMLs and cartilage defects increased with 62% (OR 1.62; 95%CI 0.92-2.84) and 53% (OR 1.53; 95%CI 0.92-2.56) in the weight gain vs the stable weight subgroup.

CONCLUSIONS

In overweight and obese women, progression of synovitis increased more than 2.5 times in a weight gain compared to a stable weight subgroup over 2.5 years. Large effect sizes were also found for the difference in progression of PF BMLs and PF cartilage defects between the weight gain and stable weight subgroup.

Knee pain as a predictor of structural progression over 4 years: data from the Osteoarthritis Initiative, a prospective cohort study

Background

There is evidence that knee pain not only is a consequence of structural deterioration in osteoarthritis (OA) but also contributes to structural progression. Clarifying this is important because targeting the factors related to knee pain may offer a clinical approach for slowing the progression of knee OA. The aim of this study was to examine whether knee pain over 1 year predicted cartilage volume loss, incidence and progression of radiographic osteoarthritis (ROA) over 4 years.

Methods

Osteoarthritis Initiative participants with no ROA (Kellgren-Lawrence grade ≤ 1) (n = 2120) and with ROA (Kellgren-Lawrence grade > 2) (n = 2249) were examined. Knee pain was assessed at baseline and 1 year using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Knee pain patterns were categorised as no pain (WOMAC pain < 5 at baseline and 1 year), fluctuating pain (WOMAC pain > 5 at either time point) and persistent pain (WOMAC pain > 5 at both time points). Cartilage volume, incidence and progression of ROA were assessed using magnetic resonance imaging and x-rays at baseline and 4-years.

Results

In both non-ROA and ROA, greater baseline WOMAC knee pain score was associated with increased medial and lateral cartilage volume loss (p ≤ 0.001), incidence (OR 1.07, 95% CI 1.01–1.13) and progression (OR 1.07, 95% CI 1.03–1.10) of ROA. Non-ROA and ROA participants with fluctuating and persistent knee pain had increased cartilage volume loss compared with those with no pain (p for trend ≤ 0.01). Non-ROA participants with fluctuating knee pain had increased risk of incident ROA (OR 1.62, 95% CI 1.04–2.54), corresponding to a number needed to harm of 19.5. In ROA the risk of progressive ROA increased in participants with persistent knee pain (OR 1.82, 95% CI 1.28–2.60), corresponding to a number needed to harm of 9.6.

Conclusions

Knee pain over 1 year predicted accelerated cartilage volume loss and increased risk of incident and progressive ROA. Early management of knee pain and controlling knee pain over time by targeting the underlying mechanisms may be important for preserving knee structure and reducing the burden of knee OA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1751-4) contains supplementary material, which is available to authorized users.

MRI-detected osteophytes of the knee: natural history and structural correlates of change

Backgroud

The natural history of semi-quantitative magnetic resonance imaging (MRI)-detected osteophytes (MRI-detected OPs) has not been described and it is unknown whether knee structural abnormalities can predict MRI-detected OP change over time. Thus, the aim of current study is to describe the natural history of knee MRI-detected OP, and to determine if knee structural abnormalities are associated with change of MRI-detected OP in a longitudinal study of older adults.

Methods

Randomly selected older adults (n = 837, mean age 63 years) had MRI at baseline and 413 of them had MRI 2.6 years later to measure MRI-detected OP, cartilage defects, cartilage volume, bone marrow lesions (BMLs), meniscal extrusion, infrapatellar fat pad (IPFP) quality score/maximum area and effusion-synovitis.

Results

Over 2.6 years, average MRI-detected OP score increased significantly in all compartments. The total MRI-detected OP score remained stable in 53% of participants, worsened (≥ 1-point increase) in 46% and decreased in 1%. Baseline cartilage defects (RR, 1.25–1.35), BMLs (RR, 1.16–1.17), meniscal extrusion (RR, 1.22–1.33) and IPFP quality score (RR, 1.08–1.20) site-specifically and independently predicted an increase in MRI-detected OP (p values all ≤ 0.05), after adjustment for covariates. Presence of IPFP abnormality was significantly associated with increased MRI-detected OPs but became non-significant after adjustment for other structural abnormalities. Total (RR, 1.27) and suprapatellar pouch effusion-synovitis (RR, 1.22) were both associated with increased MRI-detected OPs in the lateral compartment only (both p < 0.04).

Conclusion

Knee MRI-detected OPs are common in older adults and are likely to progress. The association between baseline structural abnormalities and worsening MRI-detected OPs suggest MRI-detected OP could be a consequence of multiple knee structural abnormalities.

Defining multiple joint osteoarthritis, its frequency and impact in a community-based cohort

BACKGROUND/PURPOSE

To update definitions of multiple joint osteoarthritis (MJOA), and to determine the frequency and impact of MJOA in a community-based cohort.

METHODS

Following PRISMA guidelines and with the help of a professional research librarian, we performed a systematic review in Medline using the terms osteoarthritis, generalized, polyarticular, multiple joint, and multi-joint among others, to obtain articles related to MJOA. A total of 42 articles were included for data extraction based on multiple criteria including the requirement for a clearly stated definition of OA assessed at more than one body site. We assessed frequency of these definitions in the Johnston County OA Project (JoCo OA) cohort as well as outcomes related to general health and physical function.

RESULTS

A total of 6 clearly stated definitions for MJOA were identified. These definitions were integrated with a list of 24 definitions from our previous systematic review and distilled down to produce 10 literature-derived, operationalized MJOA definitions. Based on these definitions, high frequencies of radiographic (4-74%) and symptomatic (2-52%) MJOA were found in the JoCo OA. Significant detrimental effects were seen on general health and physical function for most definitions.

CONCLUSIONS

We constructed a list of 10 summary MJOA definitions based in the literature that are frequent and associated with important clinical outcomes. These definitions capture some of the variability of MJOA phenotypes and provide a starting point for future analyses of both existing and newly initiated studies.

Structural abnormalities detected by knee magnetic resonance imaging are common in middle-aged subjects with and without risk factors for osteoarthritis

Background and purpose - Few data are available regarding structural changes present in knees without radiographically evident osteoarthritis (OA). We evaluated the prevalence of findings suggestive of knee OA by magnetic resonance imaging (MRI) in middle-aged subjects without radiographic OA with or without OA risk factors. Patients and methods - 340 subjects from the Osteoarthritis Initiative, aged 45-55 years (51% women) with Kellgren-Lawrence grade 0 in both knees, who had 3T knee MR images were eligible. 294 subjects had risk factors and 46 were without risk factors. MR images were assessed using the MOAKS scoring system. Results - At least 1 MR-detected feature was found in 96% (283/294) of subjects with risk factors and in 87% (40/46) of those without. Cartilage damage (82%), bone marrow lesions (60%), osteophytes (45%), meniscal body extrusion (32%), and synovitis-effusion (29%) were the most common findings in subjects with risk factors, while cartilage damage (67%), osteophytes (46%), meniscal body extrusion (37%), and bone marrow lesions (35%) were most common in subjects without. The prevalence of any abnormality was higher in subjects with OA risk factors than in subjects without (prevalence ratio adjusted for age and sex 1.3 [95% CI 1.1-1.6]), so was prevalence of subchondral cysts and bone marrow lesions. MR-detected structural changes were more frequent in patellofemoral joints. Interpretation - Our findings highlight the great challenge in distinguishing pathological features of early knee OA from what could be considered part of "normal ageing." Bone marrow lesions were more frequently found in subjects with multiple OA risk factors.

Association of childhood adiposity measures with adulthood knee cartilage defects and bone marrow lesions: a 25-year cohort study

OBJECTIVE

To describe the associations between childhood adiposity measures and adulthood knee cartilage defects and bone marrow lesions (BMLs) measured 25 years later.

METHODS

327 participants from the Australian Schools Health and Fitness Survey (ASHFS) of 1985 (aged 7-15 years) were followed up 25 years later (aged 31-41 years). Childhood measures (weight, height and skinfolds) were collected in 1985. Body mass index (BMI), overweight status and fat mass were calculated. Participants underwent 1.5 T knee magnetic resonance imaging (MRI) during 2008-2010, and cartilage defects and BMLs were scored from knee MRI scans. Log binomial regressions were used to examine the associations.

RESULTS

Among 327 participants (47.1% females), 21 (6.4%) were overweight in childhood. Childhood adiposity measures were associated with the increased risk of adulthood patellar cartilage defects (Weight relative risk (RR) 1.05/kg, 95% confidence interval (CI) 1.01-1.09; BMI 1.10/kg/m², 1.01-1.19; Overweight 2.22/yes, 1.21-4.08; fat mass 1.11/kg, 1.01-1.22), but not tibiofemoral cartilage defects. Childhood adiposity measures were not significantly associated with adulthood knee BMLs except for the association between childhood overweight status and adulthood patellar BMLs (RR 2.87/yes, 95% CI 1.10-7.53). These significant associations persisted after adjustment for corresponding adulthood adiposity measure.

CONCLUSION

Childhood adiposity measures were associated with the increased risk of adulthood patellar cartilage defects and, to a lesser extent, BMLs, independent of adulthood adiposity measures. These results suggest that adiposity in childhood has long-term effects on patellar structural abnormalities in young adults.

Is There a Biomechanical Link Between Patellofemoral Pain and Osteoarthritis? A Narrative Review

The patellofemoral (PF) joint is the knee compartment most commonly affected by osteoarthritis (OA). Even mild PF OA is associated with considerable pain and functional limitations. Despite its prevalence and impact, little is understood of the etiology or structural and functional features of PF OA. The clinical symptoms of PF OA, such as anterior knee pain during stair ambulation and squatting, share many similarities with PF pain in adolescents and young adults. PF joint OA is most commonly diagnosed in people aged >40 years, many of whom report a history of PF pain. As such, there is growing evidence that PF pain and PF OA form a continuum of disease. This review explores the possible relationship between the presence of PF pain and the development of PF OA. We review the evidence for altered neuromotor control and biomechanical factors that may be associated with altered PF loading in people with PF pain and PF OA. In doing so, we highlight similarities and differences that may evolve along the continuum. By improving our understanding of the neuromotor and biomechanical links between PF pain and PF OA, we may highlight potential targets for new rehabilitation strategies.

Association between Dietary Glycemic Index and Knee Osteoarthritis: The Korean National Health and Nutrition Examination Survey 2010-2012

BACKGROUND

Obesity and metabolic abnormalities are important risk factors for knee osteoarthritis (KOA). Recent epidemiologic studies have found that a high glycemic index (GI) and glycemic load (GL) diet are associated with a higher risk for metabolic complications and cardiovascular mortality.

OBJECTIVE

We aimed to examine the association between dietary GI, dietary GL, and KOA among Korean adults.

DESIGN

This was a cross-sectional study that analyzed data obtained from the Korean National Health and Nutrition Examination Survey 2010-2012.

PARTICIPANTS/SETTING

A total of 9,203 participants (5,275 women) aged ≥50 years were included.

MAIN OUTCOME MEASURES

KOA was defined as the presence of radiographic features of Kellgren-Lawrence grade ≥2. Chronic knee pain was defined as the presence of knee pain for more than 30 days during the past 3 months. Dietary information was collected using a single 24-hour recall method.

STATISTICAL ANALYSES PERFORMED

The association between the quintiles of dietary GI and dietary GL and knee conditions was analyzed using a multinomial logistic regression analysis adjusting for age, physical activity, obesity, hypertension and diabetes, serum low-density lipoprotein, and total energy intake.

RESULTS

Among the women, the association between dietary GI and symptomatic KOA was: quintile 1: 1.00 (reference); quintile 2: 1.29 (95% CI 0.87 to 1.92); quintile 3: 1.59 (95% CI 1.11 to 2.28); quintile 4: 1.74 (95% CI 1.21 to 2.51); and quintile 5: 1.77 (95% CI 1.20 to 2.60) (P=0.001). Chronic knee pain without KOA was associated with dietary GI; however, this association was not linear across quintiles. There was no significant association between dietary GI and asymptomatic KOA. Among the men, no significant association was found between dietary GI and any knee conditions. There was no significant association between dietary GL and KOA in both men and women.

CONCLUSIONS

There was a significant positive association between dietary GI and symptomatic KOA in women.

Toward classification criteria for early osteoarthritis of the knee

OBJECTIVE

To propose draft classification criteria for early stage osteoarthritis (OA) of the knee for use in a primary care setting.

METHODS

A group of basic scientists, physician-scientists, rheumatologists, orthopedic surgeons, and physiotherapists in a workshop setting discussed potential classification criteria for early osteoarthritis of the knee. The workshop was divided into sessions around relevant topics with short state of the art presentations followed by breakout sessions, consensus discussions, and consolidation into a consensus document.

RESULTS

Three classes of criteria were agreed: (1) Pain, symptoms/signs, self-reported function, and quality of life using tools such as KOOS: scoring ≤85% in at least 2 out of these 4 categories; (2) Clinical examination: at least 1 present out of joint line tenderness or crepitus; (3) Knee radiographs: Kellgren & Lawrence (KL) grade of 0 or 1. MRI is at present not recommended as an aid to identify or define early OA in routine clinical practice or primary care, in light of the absence of validated consensus criteria and the high population prevalence of structural joint changes detected by this method. Biomarkers may have future utility in early OA classification, but no individual or set of biomarkers is yet robust enough.

CONCLUSION

Based on our consensus proposal, draft classification criteria for early OA of the knee for use in clinical studies should include patient reported outcomes such as pain and function, together with clinical signs and KL grade 0-1 on radiographs.

Inflammation and glucose homeostasis are associated with specific structural features among adults without knee osteoarthritis: a cross-sectional study from the osteoarthritis initiative

Background

Greater age and body mass index are strong risk factors for osteoarthritis (OA). Older and overweight individuals may be more susceptible to OA because these factors alter tissue turnover in menisci, articular cartilage, and bone via altered glucose homeostasis and inflammation. Understanding the role of inflammation and glucose homeostasis on structural features of early-stage OA may help identify therapeutic targets to delay or prevent the onset of OA among subsets of adults with these features. We examined if serum concentrations of glucose homeostasis (glucose, glycated serum protein [GSP]) or inflammation (C-reactive protein [CRP]) were associated with prevalent knee bone marrow lesions (BMLs) or effusion among adults without knee OA.

Methods

We conducted a cross-sectional study using baseline data from the Osteoarthritis Initiative. We selected participants who had no radiographic knee OA but were at high risk for knee OA. Blinded staff conducted assays for CRP, GSP, and glucose. Readers segmented BML volume and effusion using semi-automated programs. Our outcomes were prevalent BML (knee with a BML volume > 1 cm³) and effusion (knee with an effusion volume > 7.5 cm³). We used logistic regression models with CRP, GSP, or glucose concentrations as the predictors. We adjusted for age, sex, body mass index (BMI), and Physical Activity Scale for the Elderly (PASE) scores.

Results

We included 343 participants: mean age = 59 ± 9 years, BMI = 27.9 ± 4.5 kg/m², PASE score = 171 ± 82, and 64% female. Only CRP was associated with BML prevalence (odds ratio [OR] = 1.43, 95% confidence interval [CI] = 1.09 to 1.87). For effusion, we found an interaction between BMI and CRP: only among adults with a BMI <25 kg/m² was there a significant trend towards a positive association between CRP and effusion (OR = 1.40, 95% CI = 1.00 to 1.97). We detected a U-shaped relationship between GSP and effusion prevalence. Fasting glucose levels were not significantly associated with the presence of baseline effusion or BML.

Conclusions

Among individuals without knee OA, CRP may be related to the presence of BMLs and effusion among normal weight individuals. Abnormal GSP may be associated with effusion. Future studies should explore whether inflammation and glucose homeostasis are predictive of symptomatic knee OA.

Patellofemoral Joint Loads During Running at the Time of Return to Sport in Elite Athletes With ACL Reconstruction

BACKGROUND

Patellofemoral joint pain and degeneration are common in patients who undergo anterior cruciate ligament reconstruction (ACLR). The presence of patellofemoral joint pain significantly affects the patient's ability to continue sport participation and may even affect participation in activities of daily living. The mechanisms behind patellofemoral joint pain and degeneration are unclear, but previous research has identified altered patellofemoral joint loading in individuals with patellofemoral joint pain when running. It is unclear whether this process occurs after ACLR.

PURPOSE

To assess the patellofemoral joint stresses during running in ACLR knees and compare the findings to the noninjured knee and matched control knees.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-four elite sports practitioners who had undergone ACLR and 34 age- and sex-matched controls participated in the study. The participants' running gait was assessed via 3D motion capture, and knee loads and forces were calculated by use of inverse dynamics.

RESULTS

A significance difference was found in knee extensor moment, knee flexion angles, patellofemoral contact force (about 23% greater), and patellofemoral contact pressure (about 27% greater) between the ACLR and the noninjured limb ( P ≤ .04) and between the ACLR and the control limb ( P ≤ .04); no significant differences were found between the noninjured and control limbs ( P ≥ .44).

CONCLUSION

Significantly greater levels of patellofemoral joint stress and load were found in the ACLR knee compared with the noninjured and control knees.

CLINICAL RELEVANCE

Altered levels of patellofemoral stress in the ACLR knee during running may predispose individuals to patellofemoral joint pain.

Patellofemoral morphology and alignment: reference values and dose-response patterns for the relation to MRI features of patellofemoral osteoarthritis

OBJECTIVE

We aimed to (1) determine reference values for trochlear morphology and patellofemoral (PF) alignment in adults without magnetic resonance imaging (MRI)-defined PF full thickness cartilage damage or knee pain; and (2) evaluate dose-response patterns for these measures with prevalent MRI-defined PF structural damage and/or knee pain.

DESIGN

The Framingham Community Cohort is a population-based sample of ambulatory adults aged ≥50 years. We evaluated six morphology and alignment measures using MRI (n = 985), and reported reference values (mean ± 2SD) in a subsample without MRI-defined PF full thickness cartilage damage or knee pain (n = 563). With restricted cubic spline Poisson regression, we evaluated dose-response patterns of each of the six measures with prevalent MRI-defined PF structural damage or joint pain. Our primary outcome was full thickness cartilage damage.

RESULTS

For dose-response curves, prevalence ratios (PR) increased monotonically for all measures except patellar tilt, which rose with both lateral and medial tilt. Associations were generally strongest in the lateral PF compartment. PR for the strongest predictors of full thickness cartilage damage reached clinical relevance (PR > 1.5) at sulcus angle (SA) ≥135.0°; patellar tilt angle at ≤1.0° and ≥15.0°; and bisect offset ≥57.0%. Lateral trochlear inclination (LTI) achieved PR > 1.5 at ≤23.0° for full thickness cartilage damage with pain.

CONCLUSIONS

SA, patellar tilt, and bisect offset were most strongly associated with full thickness cartilage damage. LTI, patellar tilt and bisect offset had stronger associations with the addition of pain. These findings contribute to better identifying a subset of patients who may benefit from mechanically based interventions.

Knee tissue lesions and prediction of incident knee osteoarthritis over 7 years in a cohort of persons at higher risk

OBJECTIVE

Among high risk individuals, whether knee lesions in tissues involved in osteoarthritis (OA) can improve prediction of knee OA is unclear. We hypothesized that models predicting (1) incident osteophytes and (2) incident osteophytes and joint space narrowing can be improved by including symptoms or function, and further improved by lesion status.

DESIGN

In Osteoarthritis Initiative (OAI) participants with normal knee X-rays, we assessed cartilage damage, bone marrow lesions (BMLs), and menisci. Cox proportional hazards models were used to develop risk prediction models for risk of each outcome. Nested models (increasingly larger baseline covariable sets) were compared using likelihood ratio tests and Schwarz Bayesian Information Criterion (SBC). Model discrimination used receiver operating characteristic (ROC) curves and area under the curve (AUC).

RESULTS

In 841 participants [age 59.6, body mass index (BMI) 26.7, 55.9% women] over up to 7 years follow-up, each larger set improved prediction (+hand OA, injury, surgery, activities; +symptoms/function). Prediction was further improved by including cartilage damage both compartments, BMLs both compartments, meniscal tear, meniscal extrusion, sum of lesion types, number of subregions with cartilage damage, number of subregions with BMLs, and (concurrently) subregion number with cartilage damage, subregion number with BMLs, and meniscal tear. AUCs were ≥0.80 for both outcomes for number of subregions with cartilage damage and the combined model.

CONCLUSIONS

Among persons at higher risk for knee OA with normal X-rays, MRI tissue lesions improved prediction of mild as well as moderate disease. These findings support that disease onset is likely occurring during the "high-risk" period and encourage a reorientation of approach.

The Prevalence of Meniscal Pathology in Asymptomatic Athletes

BACKGROUND

Meniscal pathology is a commonly seen orthopedic condition that can affect a wide age range of patients. Athletes subject their menisci to an increased amount of stress during their careers and may increase their risk of meniscal pathology.

OBJECTIVE

The purpose of this systematic review is to evaluate the prevalence of isolated meniscal pathology in asymptomatic athletes.

METHODS

A systematic review was undertaken to determine the prevalence of meniscal pathology in asymptomatic athletes. A search of multiple databases was conducted. Recreational and higher-level athletes were included. Fourteen articles including 295 athletes (208 male, 87 female) were identified for inclusion (age range 14-66 years, mean 31.2 years). Meniscal pathology was visualized with magnetic resonance imaging and graded on a 1-4 scale (grades 1 and 2 indicating intrasubstance damage, grades 3 and 4 indicating a tear).

RESULTS

There was an overall prevalence of 27.2 % (105/386) of knees with intrasubstance meniscal damage (grades 1 and 2), and 3.9 % (15/386) of knees with a tear (grades 3 and 4). When athletes were split into those who participate in pivoting sports versus non-pivoting sports, pivoting athletes showed an overall prevalence of 15.3 % (31/202) of knees with intrasubstance meniscal pathology and 2.5 % (5/202) of knees with a tear. Non-pivoting athletes showed a prevalence of 54.5 % (61/112) of knees with intrasubstance meniscal pathology and 5.4 % (6/112) of knees with a tear.

CONCLUSION

The overall prevalence of isolated meniscal pathology in asymptomatic athletes was 31.1 % (27.2 % with intrasubstance meniscal damage and 3.9 % with a meniscal tear). More studies of age-comparable, non-athletic populations are necessary for direct comparison with these groups.

The prevalence of radiographic and MRI-defined patellofemoral osteoarthritis and structural pathology: a systematic review and meta-analysis

BACKGROUND

Patellofemoral osteoarthritis (PF OA) is more prevalent than previously thought and contributes to patient's suffering from knee OA. Synthesis of prevalence data can provide estimates of the burden of PF OA.

OBJECTIVE

This study aims to conduct a systematic review and meta-analysis on the prevalence of PF OA and structural damage based on radiography and MRI studies in different populations.

METHODS

We searched six electronic databases and reference lists of relevant cross-sectional and observational studies reporting the prevalence of PF OA. Two independent reviewers appraised methodological quality. Where possible, data were pooled using the following categories: radiography and MRI studies.

RESULTS

Eighty-five studies that reported the prevalence of patellofemoral OA and structural damage were included in this systematic review. Meta-analysis revealed a high prevalence of radiographic PF OA in knee pain or symptomatic knee OA (43%), radiographic knee OA or at risk of developing OA (48%) and radiographic and symptomatic knee OA (57%) cohorts. The MRI-defined structural PF damage in knee pain or symptomatic population was 32% and 52% based on bone marrow lesion and cartilage defect, respectively.

CONCLUSION

One half of people with knee pain or radiographic OA have patellofemoral involvement. Prevalence of MRI findings was high in symptomatic and asymptomatic population. These pooled data and the variability found can provide evidence for future research addressing risk factors and treatments for PF OA.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42016035649).

Histopathological subgroups in knee osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a heterogeneous, multi-tissue disease. We hypothesised that different histopathological features characterise different stages during knee OA progression, and that discrete subgroups can be defined based on validated measures of OA histopathological features.

DESIGN

Medial tibial plateaux and synovium were from 343 post-mortem (PM) and 143 OA arthroplasty donations. A 'chondropathy/osteophyte' group (n = 217) was classified as PM cases with osteophytes or macroscopic medial tibiofemoral chondropathy lesions ≥grade 3 to represent pre-surgical (early) OA. 'Non-arthritic' controls (n = 48) were identified from the remaining PM cases. Mankin histopathological scores were subjected to Rasch analysis and supplemented with histopathological scores for subchondral bone marrow replacement and synovitis. Item weightings were derived by principle components analysis (PCA). Histopathological subgroups were sought using latent class analysis (LCA).

RESULTS

Chondropathy, synovitis and osteochondral pathology were each associated with OA at arthroplasty, but each was also identified in some 'non-arthritic' controls. Tidemark breaching in the chondropathy/osteophyte group was greater than in non-arthritic controls. Three histopathological subgroups were identified, characterised as 'mild OA', or 'severe OA' with mild or moderate/severe synovitis.

CONCLUSIONS

Presence and severity of synovitis helps define distinct histopathological OA subgroups. The absence of a discrete 'normal' subgroup indicates a pathological continuum between normality and OA status. Identifying specific pathological processes and their clinical correlates in OA subgroups has potential to accelerate the development of more effective therapies.

Number of Persons With Symptomatic Knee Osteoarthritis in the US: Impact of Race and Ethnicity, Age, Sex, and Obesity

OBJECTIVE

The prevalence of symptomatic knee osteoarthritis (OA) has been increasing over the past several decades in the US, concurrent with an aging population and the growing obesity epidemic. We quantify the impact of these factors on the number of persons with symptomatic knee OA in the early decades of the 21st century.

METHODS

We calculated the prevalence of clinically diagnosed symptomatic knee OA from the National Health Interview Survey 2007-2008 and derived the proportion with advanced disease (defined as Kellgren/Lawrence grade 3 or 4) using the Osteoarthritis Policy Model, a validated simulation model of knee OA. Incorporating contemporary obesity rates and population estimates, we calculated the number of persons living with symptomatic knee OA.

RESULTS

We estimate that approximately 14 million persons had symptomatic knee OA, with advanced OA comprising more than half of those cases. This includes more than 3 million persons of racial/ethnic minorities (African American, Hispanic, and other). Adults younger than 45 years of age represented nearly 2 million cases of symptomatic knee OA and individuals between 45 and 65 years of age comprised 6 million more cases.

CONCLUSION

More than half of all persons with symptomatic knee OA are younger than 65 years of age. As many of these younger persons will live for 3 decades or more, there is substantially more time for greater disability to occur, and policymakers should anticipate health care utilization for knee OA to increase in the upcoming decades. These data emphasize the need for the deployment of innovative prevention and treatment strategies for knee OA, especially among younger persons.

A novel aragonite-based scaffold for osteochondral regeneration: early experience on human implants and technical developments

INTRODUCTION

Chondral and osteochondral lesions represent a debilitating disease. Untreated lesions remain a risk factor for more extensive joint damage. The objective of this clinical study is to evaluate safety and early results of an aragonite-based scaffold used for osteochondral unit repair, by analysing both clinical outcome and MRI results, as well as the benefits of the procedure optimization through novel tapered shaped implants.

METHODS

A crystalline aragonite bi-phasic scaffold was implanted in patients affected by focal chondral-osteochondral knee lesions of the condyle and trochlea. Twenty-one patients (17 men, 4 women with a mean age of 31.0 ± 8.6 years) without severe OA received tapered shaped implants for the treatment of 2.5 ±1.7 cm² sized defects. The control group consisted of 76 patients selected according to the same criteria from a database of patients who previously underwent implantation of cylindrical-shaped implants. The clinical outcome of all patients was evaluated with the IKDC subjective score, the Lysholm score, and all 5 KOOS subscales administered preoperatively and at 6 and 12 months after surgery, while MRI evaluation was performed at the 12 month follow-up.

RESULTS

A statistically significant improvement in all clinical scores was documented both in the tapered implants and the cylindrical group. No difference could be detected in the comparison between the improvement obtained with the two implant types, neither in the clinical nor in imaging evaluations. A difference could be detected instead in terms of revision rate, which was lower in the tapered implant group with no implant removal - 0% vs 8/76-10.5% failures in the cylindrical implants.

CONCLUSIONS

This study highlighted both safety and potential of a novel aragonite-based scaffold for the treatment of chondral and osteochondral lesions in humans. A tapered shape relative to the cylindrical shaped implant design, improved the scaffold's safety profile. Tapered scaffolds maintain the clinical improvement observed in cylindrical implants while reducing the postoperative risk of revision surgery. This aragonite-based implant was associated with a significant clinical improvement at the 12 month follow-up. Moreover, MRI findings revealed graft integration with good bone and cartilage formation.