Natural history of cartilage damage and osteoarthritis progression on magnetic resonance imaging in a population-based cohort with knee pain

Exploring the potential of the sit-to-stand test for self-assessment of physical condition in advanced knee osteoarthritis patients using computer vision

Introduction

Knee osteoarthritis (KOA) is a prevalent condition often associated with a decline in patients' physical function. Objective self-assessment of physical conditions poses challenges for many advanced KOA patients. To address this, we explored the potential of a computer vision method to facilitate home-based physical function self-assessments.

Methods

We developed and validated a simple at-home artificial intelligence approach to recognize joint stiffness levels and physical function in individuals with advanced KOA. One hundred and four knee osteoarthritis (KOA) patients were enrolled, and we employed the WOMAC score to evaluate their physical function and joint stiffness. Subsequently, patients independently recorded videos of five sit-to-stand tests in a home setting. Leveraging the AlphaPose and VideoPose algorithms, we extracted time-series data from these videos, capturing three-dimensional spatiotemporal information reflecting changes in key joint angles over time. To deepen our study, we conducted a quantitative analysis using the discrete wavelet transform (DWT), resulting in two wavelet coefficients: the approximation coefficients (cA) and the detail coefficients (cD).

Results

Our analysis specifically focused on four crucial joint angles: "the right hip," "right knee," "left hip," and "left knee." Qualitative analysis revealed distinctions in the time-series data related to functional limitations and stiffness among patients with varying levels of KOA. In quantitative analysis, we observed variations in the cA among advanced KOA patients with different levels of physical function and joint stiffness. Furthermore, there were no significant differences in the cD between advanced KOA patients, demonstrating different levels of physical function and joint stiffness. It suggests that the primary difference in overall movement patterns lies in the varying degrees of joint stiffness and physical function among advanced KOA patients.

Discussion

Our method, designed to be low-cost and user-friendly, effectively captures spatiotemporal information distinctions among advanced KOA patients with varying stiffness levels and functional limitations utilizing smartphones. This study provides compelling evidence for the potential of our approach in enabling self-assessment of physical condition in individuals with advanced knee osteoarthritis.

Physical and psychosocial characteristics differ between individuals with knee pain and different knee osteoarthritis diagnostic criteria

PURPOSE

Knee pain and osteoarthritis (OA) are common and often lead to disability among older adults. Existing published evidence, however, utilizes differing criteria to define studies' knee OA populations. We, therefore, aimed to determine whether differences exist in the characteristics of individuals with the presence of knee pain and different diagnostic criteria for knee OA.

METHODS

The Promoting Independence in Seniors with Arthritis (PISA) study is a longitudinal observational study of individuals with and without knee pain and knee OA recruited from the orthopaedics clinic of the Universiti Malaya Medical Centre and the local hospital catchment. Patients were diagnosed with OA based on the American College of Rheumatology (ACR) criteria, the presence of knee pain, and a history of physician-diagnosed knee OA. Psychosocial parameters were measured using validated measures for social participation, independence, and ability to perform activities of daily living, and life satisfaction.

RESULTS

Of the 230 included participants, mean age was 66.9 years (standard deviation: 7.2) and 166 (72.2%) were women. Kappa agreement between ACR criteria and knee pain was 0.525 and for ACR and physician-diagnosed OA it was 0.325. Binomial logistic regression analysis showed that weight, anxiety, and handgrip strength (HGS) were predictive of ACR OA. Knee pain was only predicted by HGS but not weight and anxiety. Physician-diagnosed OA was predicted by weight and HGS but not anxiety. HGS was predictive of ACR OA, knee pain, and physician-diagnosed OA.

CONCLUSION

Our study showed that the characteristics of patients with OA are different, physically and psychosocially, depending on the criteria used. Poor agreement was observed between radiological diagnosis and the other diagnostic criteria. Our findings have important implications for the interpretation and comparison of published studies using different OA criteria.

KEY MESSAGES

Gait, physical activity and tibiofemoral cartilage damage: a longitudinal machine learning analysis in the Multicenter Osteoarthritis Study

OBJECTIVE

To (1) develop and evaluate a machine learning model incorporating gait and physical activity to predict medial tibiofemoral cartilage worsening over 2 years in individuals without advanced knee osteoarthritis and (2) identify influential predictors in the model and quantify their effect on cartilage worsening.

DESIGN

An ensemble machine learning model was developed to predict worsened cartilage MRI Osteoarthritis Knee Score at follow-up from gait, physical activity, clinical and demographic data from the Multicenter Osteoarthritis Study. Model performance was evaluated in repeated cross-validations. The top 10 predictors of the outcome across 100 held-out test sets were identified by a variable importance measure. Their effect on the outcome was quantified by g-computation.

RESULTS

Of 947 legs in the analysis, 14% experienced medial cartilage worsening at follow-up. The median (2.5-97.5th percentile) area under the receiver operating characteristic curve across the 100 held-out test sets was 0.73 (0.65-0.79). Baseline cartilage damage, higher Kellgren-Lawrence grade, greater pain during walking, higher lateral ground reaction force impulse, greater time spent lying and lower vertical ground reaction force unloading rate were associated with greater risk of cartilage worsening. Similar results were found for the subset of knees with baseline cartilage damage.

CONCLUSIONS

A machine learning approach incorporating gait, physical activity and clinical/demographic features showed good performance for predicting cartilage worsening over 2 years. While identifying potential intervention targets from the model is challenging, lateral ground reaction force impulse, time spent lying and vertical ground reaction force unloading rate should be investigated further as potential early intervention targets to reduce medial tibiofemoral cartilage worsening.

3D Bioprinting Strategies for Articular Cartilage Tissue Engineering

Articular cartilage is the avascular and aneural tissue which is the primary connective tissue covering the surface of articulating bone. Traumatic damage or degenerative diseases can cause articular cartilage injuries that are common in the population. As a result, the demand for new therapeutic options is continually increasing for older people and traumatic young patients. Many attempts have been made to address these clinical needs to treat articular cartilage injuries, including osteoarthritis (OA); however, regenerating highly qualified cartilage tissue remains a significant obstacle. 3D bioprinting technology combined with tissue engineering principles has been developed to create biological tissue constructs that recapitulate the anatomical, structural, and functional properties of native tissues. In addition, this cutting-edge technology can precisely place multiple cell types in a 3D tissue architecture. Thus, 3D bioprinting has rapidly become the most innovative tool for manufacturing clinically applicable bioengineered tissue constructs. This has led to increased interest in 3D bioprinting in articular cartilage tissue engineering applications. Here, we reviewed current advances in bioprinting for articular cartilage tissue engineering.

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.

Magnetic resonance imaging predictors (cartilage, osteophytes and meniscus) of prevalent and 3-year incident medial and lateral tibiofemoral knee joint tenderness and patellofemoral grind

Objective

To identify magnetic resonance imaging (MRI) predictors (cartilage [C], osteophytes [O] and meniscus [M] scores) of prevalent and 3-year incident medial tibiofemoral (MTF) and lateral tibiofemoral (LTF) knee joint tenderness and patellofemoral (PF) grind. 

Methods

Population-based knee pain cohort aged 40–79 was assessed at baseline (N = 255), 3- and 7-year follow-up (N = 108 × 2 = 216). COM scores were measured at 6/8/6 subregions respectively. Age-sex-BMI adjusted logistic models predicted prevalence versus relevant COM predictors (medial, lateral or patellar / trochlear groove scores). Fully adjusted models also included all relevant COM predictors. Binary generalized estimating equations models predicting 3-year incidence were also adjusted for individual follow-up time between cycles.

Results

Significant predictors of prevalent MTF tenderness: medial femoral cartilage (fully adjusted odds ratio [aOR] 1.84; 95% confidence interval [CI] 1.11, 3.05), female (aOR = 3.05; 1.67, 5.58), BMI (aOR = 1.53 per 5 units BMI; 1.10, 2.11). Predictors of prevalent LTF tenderness: female (aOR = 2.18; 1.22, 3.90). There were no predictors of prevalent PF grind in the fully adjusted model. However, medial patellar osteophytes was predictive in the age-sex-BMI adjusted model. There were no predictors of 3-year incident MTF tenderness. Predictors of 3-year incident LTF tenderness: female (aOR = 3.83; 1.25, 11.77). Predictors of 3-year incident PF grind: lateral patellar osteophytes (aOR = 4.82; 1.69, 13.77). In the age-sex-BMI adjusted model, patellar cartilage was also a predictor.

Conclusion

We explored potential MRI predictors of prevalent and 3-year incident MTF/LTF knee joint tenderness and PF grind. These findings could guide preemptive strategies aimed at reducing these symptoms in the present and future (3-year incidence).

Stromal vascular fraction therapy for knee osteoarthritis: a systematic review

Background:

Regenerative cell therapies, such as adipose-derived stromal vascular fraction (SVF), have been postulated as potential treatments for knee osteoarthritis (KOA).

Objectives:

To assess the efficacy and safety of SVF treatment against placebo and other standard therapies for treating KOA in adult patients.

Design:

A systematic review.

Data sources and methods:

We searched the following databases: MEDLINE via PubMed, Epistemonikos, PEDro, DynaMed, TripDatabase, Elsevier via Clinicalkey and Cochrane Controlled Trials Register. We included prospective interventional studies where treatment with SVF in adults with KOA was compared against placebo or other standard therapies, and results were objectively measured with at least one widely recognised osteoarthritis scale.

Results:

Among 266 studies published until May 2021, nine met our inclusion criteria. A total of 239 patients (274 knees) were included in our study. The follow-up ranged from 6 to 24 months. Six studies had a control group (only one being placebo). All studies showed that SVF improved pain and functionality measured, in most cases, with the visual analogue scale and the Western Ontario and McMaster Universities Osteoarthritis Index. In addition, five studies reported an improvement in anatomical structures, as detected in MR images. However, the number of cells contained in SVF varied substantially between different studies, which could induce a comparison bias.

Conclusion:

Although based on a small number of dissimilar studies, SVF was considered a safe treatment for KOA and could be promising in terms of pain, functionality and anatomical structure improvement. However, SVF products need to be standardised, the number of cells homogenised and the use of concomitant treatments reduced to establish proper comparisons.

Registration:

PROSPERO registration number: CRD42021284187.

Analysis of the Effect of Component Ratio Imbalances on Selected Mechanical Properties of Seasoned, Medium Viscosity Bone Cements

The paper presents the results of experimental strength tests of specimens made of two commercially available bone cements subjected to compression, that is a typical variant of load of this material during use in the human body, after it has been used for implantation of prostheses or supplementation of bone defects. One of the factors analysed in detail was the duration of cement seasoning in Ringer's solution that simulates the aggressive environment of the human body and material degradation caused by it. The study also focused on the parameters of quantitative deviation from the recommended proportions of liquid (MMA monomer, accelerator and stabiliser) and powder (PMMA prepolymer and initiator) components, i.e., unintentional inaccuracy of component proportioning at the stage of cement mass preparation. Statistical analysis has shown the influence of these factors on the decrease in compressive strength of the cements studied, which may be of significant importance in operational practice.

Diagnostics of Articular Cartilage Damage Based on Generated Acoustic Signals Using ANN—Part II: Patellofemoral Joint

Cartilage loss due to osteoarthritis (OA) in the patellofemoral joint provokes pain, stiffness, and restriction of joint motion, which strongly reduces quality of life. Early diagnosis is essential for prolonging painless joint function. Vibroarthrography (VAG) has been proposed in the literature as a safe, noninvasive, and reproducible tool for cartilage evaluation. Until now, however, there have been no strict protocols for VAG acquisition especially in regard to differences between the patellofemoral and tibiofemoral joints. The purpose of this study was to evaluate the proposed examination and acquisition protocol for the patellofemoral joint, as well as to determine the optimal examination protocol to obtain the best diagnostic results. Thirty-four patients scheduled for knee surgery due to cartilage lesions were enrolled in the study and compared with 33 healthy individuals in the control group. VAG acquisition was performed prior to surgery, and cartilage status was evaluated during the surgery as a reference point. Both closed (CKC) and open (OKC) kinetic chains were assessed during VAG. The selection of the optimal signal measures was performed using a neighborhood component analysis (NCA) algorithm. The classification was performed using multilayer perceptron (MLP) and radial basis function (RBF) neural networks. The classification using artificial neural networks was performed for three variants: I. open kinetic chain, II. closed kinetic chain, and III. open and closed kinetic chain. The highest diagnostic accuracy was obtained for variants I and II for the RBF 9-35-2 and MLP 10-16-2 networks, respectively, achieving a classification accuracy of 98.53, a sensitivity of 0.958, and a specificity of 1. For variant III, a diagnostic accuracy of 97.79 was obtained with a sensitivity and specificity of 0.978 for MLP 8-3-2. This indicates a possible simplification of the examination protocol to single kinetic chain analyses.

Treatment of Malalignment and Cartilage Injury: High Tibial Osteotomy With a Concomitant Osteochondral Allograft to the Medial Femoral Condyle and Lateral and Medial Partial Meniscectomy

In patients with full-thickness focal cartilage defects, osteochondral allograft is a technique for restoration of hyaline cartilage; however, in patients with genu varum, the diseased compartment of the knee is generally offloaded as well. A high tibial osteotomy presents a biomechanical solution to malalignment of the knee and offloading of the diseased compartment of the knee. The purpose of this Technical Note is to present our preferred technique to treat focal cartilage damage in a varus misaligned knee coupling a high tibial osteotomy with an osteochondral allograft to the medial femoral condyle, along with partial medial and lateral meniscectomy.

Evaluation of the Effect of Selected Physiological Fluid Contaminants on the Mechanical Properties of Selected Medium-Viscosity PMMA Bone Cements

Revision surgeries several years after the implantation of the prosthesis are unfavorable from the patient’s point of view as they expose him to additional discomfort, to risk of complications and are expensive. One of the factors responsible for the aseptic loosening of the prosthesis is the gradual degradation of the cement material as a result of working under considerable loads, in an aggressive environment of the human body. Contaminants present in the surgical field may significantly affect the durability of the bone cement and, consequently, of the entire bone-cement-prosthesis system. The paper presents the results of an analysis of selected mechanical properties of two medium-viscosity bone cements DePuy CMW3 Gentamicin and Heraeus Palamed, for the samples contaminated with saline and blood in the range of 1–10%. The results obtained for compressive strength and modulus of elasticity were subjected to statistical analysis, which estimated the nature of changes in these parameters depending on the amount and type of contamination and their statistical significance.

Diagnostics of Articular Cartilage Damage Based on Generated Acoustic Signals Using ANN-Part I: Femoral-Tibial Joint

Osteoarthritis (OA) is a chronic, progressive disease which has over 300 million cases each year. Some of the main symptoms of OA are pain, restriction of joint motion and stiffness of the joint. Early diagnosis and treatment can prolong painless joint function. Vibroarthrography (VAG) is a cheap, reproducible, non-invasive and easy-to-use tool which can be implemented in the diagnostic route. The aim of this study was to establish diagnostic accuracy and to identify the most accurate signal processing method for the detection of OA in knee joints. In this study, we have enrolled a total of 67 patients, 34 in a study group and 33 in a control group. All patients in the study group were referred for surgical treatment due to intraarticular lesions, and the control group consisted of healthy individuals without knee symptoms. Cartilage status was assessed during surgery according to the International Cartilage Repair Society (ICRS) and vibroarthrography was performed one day prior to surgery in the study group. Vibroarthrography was performed in an open and closed kinematic chain for the involved knees in the study and control group. Signals were acquired by two sensors placed on the medial and lateral joint line. Using the neighbourhood component analysis (NCA) algorithm, the selection of optimal signal measures was performed. Classification using artificial neural networks was performed for three variants: I—open kinetic chain, II—closed kinetic chain, and III—open and closed kinetic chain. Vibroarthrography showed high diagnostic accuracy in determining healthy cartilage from cartilage lesions, and the number of repetitions during examination can be reduced only to closed kinematic chain.

Outcomes of Bulk Fresh Osteochondral Allografts for Cartilage Restoration in the Knee

BACKGROUND

Symptomatic osteochondral defects of the knee in young patients can cause substantial disability and predispose to osteoarthritis. Fresh osteochondral allografts (FOCAs) are a treatment option for such defects. With our institution having one of the longest-running FOCA programs, we investigated the long-term outcomes of bulk FOCA in the knee, focusing on graft survivorship, function, complications, and reoperation.

METHODS

A total of 244 patients underwent bulk FOCA in the knee from 1972 to 2018, with a mean age of 37.8 years (range, 10 to 75 years) and a mean follow-up of 9.0 years (range, 1.0 to 29.8 years). Cartilage defects were very large and uncontained, such that they were not amenable to plug transplantation. Survivorship according to Kaplan-Meier analysis was the primary outcome, and failure was defined as conversion to total knee arthroplasty, repeat allograft, graft removal, knee arthrodesis, or amputation. Functional outcome was evaluated with use of the modified Hospital for Special Surgery (mHSS) score, and radiographic evidence of osteoarthritis was classified with use of the Kellgren-Lawrence grading scale.

RESULTS

Graft survivorship was 86.6% at 5 years, 73.3% at 10 years, 58.1% at 15 years, 43.7% at 20 years, 31.9% at 25 years, and 22.6% at 30 years. The most common complications were pain (14.8%), malalignment (13.9%), and stiffness (5.8%). A total of 93 grafts (38.1%) failed at a mean of 11.0 years (range, 0.5 to 34.0 years). The mean mHSS score improved significantly, from 68.7 (range, 19 to 91) preoperatively to 80.3 (range, 52 to 100) at the time of the latest follow-up (p < 0.001). Preoperative mHSS score had a negative correlation with Kellgren-Lawrence grade at the time of the latest follow-up. Multivariate analysis revealed that graft location (i.e., medial-sided or multiple grafts) and increased age were significantly negatively associated with survival. Ten-year survival was >80% in patients below 50 years old, but <40% in patients >60 years old.

CONCLUSIONS

Bulk FOCA provided promising long-term graft survival and functional improvement in patients <50 years old. It can delay or prevent the need for total knee arthroplasty in young patients. Older patients and patients with a medial-sided graft, or multiple grafts within the same knee, had a less favorable prognosis.

LEVEL OF EVIDENCE

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

A whole-joint, unidimensional, irreversible, and fine-grained MRI knee osteoarthritis severity score, based on cartilage, osteophytes and meniscus (OA-COM)

Objective

To develop a whole-joint, unidimensional, irreversible, and fine-grained MRI knee osteoarthritis (OA) severity score, based on cartilage, osteophytes and meniscus (OA-COM), and to predict progression across different severity states using OA-COM as outcome and clinical variables as predictors.

Methods

Population-based knee pain cohort aged 40–79 was assessed at baseline and 7-year follow-up. OA-COM score was defined as the sum of MRI scores for cartilage, osteophytes and menisci, measured at 6, 8 and 6 sites, total score 0–54. To anchor severity levels, we fit cross-sectional logistic models using OA-COM to predict Kellgren-Lawrence (KL) grades in subsets at or one point below each grade. OA-COM threshold scores were selected on sensitivity, specificity, positive and negative predictive value. We developed longitudinal logistic models for OA-COM progression over each threshold over 7 years. Potential predictors included age, sex, BMI, malalignment, physical exam effusion, quadriceps weakness, and crepitus, selected on area under the receiver operating characteristic curve (AUC) and Akaike’s Information Criterion (AIC).

Results

Optimal OA-COM thresholds were 12, 18, 24 and 30, for KL grades 1 to 4. Significant predictors of progression (depending on threshold) included physical exam effusion, malalignment and female sex, with other selected predictors age, BMI and crepitus.

Conclusion

OA-COM (0–54 range) is a whole-joint, unidimensional, irreversible, and fine-grained MRI OA severity score reflecting cartilage, osteophytes and menisci. OA-COM scores 12, 18, 24 and 30 are equivalent to KL grades 1 to 4, while offering fine-grained differentiation of states between KL grades, and within pre-radiographic disease (KL = 0) or late-stage disease (KL = 4). In modeling, several clinical variables predicted progression across different states over 7 years.

Identifying the Phenotypic and Temporal Heterogeneity of Knee Osteoarthritis: Data From the Osteoarthritis Initiative

Objective: Previous studies discussing phenotypic and temporal heterogeneity of knee osteoarthritis (KOA) separately have fatal limitations that either clustering patients with similar severity or assuming all knees have a single common progression pattern, which are unreliable. This study tried to uncover more reliable information on phenotypic and temporal heterogeneity of KOA. Design: Data were from Osteoarthritis Initiative database. Six hundred and seventy-eight unilateral knees that have greater Kellgren and Lawrence (KL) grade than the contralateral knees at baseline and in all follow-up 48 months were included. Measurements of biomarkers at baseline were chosen. Subtype and Stage Inference model (SuStaIn) was applied as a subtype-progression model to identify subtypes, subtype biomarker progress sequences and stages of KOA. Results: This study identified three subtypes which account for 15, 61, and 24% of knees, respectively. Each subtype has distinct subtype biomarker progress sequence. For knees with KL grade 0/1, 2, 3, and 4, they have different distributions on stage and 26, 53, 89, and 95% of them are strongly assigned to subtypes. When assessing whether a knee has KL (grade ≥ 2), subtypes and stages from subtypes-progression model (SuStaIn) are significantly better fitting than those from subtypes-only (mixture of Gaussians) (likelihood ratio = 105.59, p = 2.2 × 10^-16) or stages-only (SuStaIn where setting c = 1) (likelihood ratio = 58.04, p = 2.57 × 10^-14) model. Stages in subtypes-progression model has greater β than stages-only model. Subtypes from subtypes-progression model have no statistical significance. Conclusions: For subtypes-progression model, stages contain more complete temporal information and subtypes are closer to real OA subtypes.

Low Back Pain as a Risk Factor for Recurrent Falls in People With Knee Osteoarthritis

OBJECTIVE

Knee osteoarthritis (OA) has been suggested to increase the risk of falls. Low back pain (LBP) is a potential risk factor for falls in people with knee OA, but this issue has not been addressed adequately in previous studies. The objective of this study was to investigate the relationship between LBP and falls in people with knee OA in a 12-month period.

METHODS

Participants with knee OA (Kellgren/Lawrence [K/L] grade ≥1) completed questionnaires for LBP and falls that occurred in the preceding 12 months. Binary and ordinal logistic regression analyses were performed to assess the relationship between LBP or moderate-to-severe LBP (numeric rating scale ≥4 points) and any fall (≥1 fall) or recurrent falls (≥2 falls) after adjustment for age, sex, K/L grade, knee pain severity, and quadriceps strength. Sensitivity analyses were performed excluding people with sciatica, nonchronic LBP, K/L grade 1, and those receiving pain medications.

RESULTS

We included 189 participants (ages 61-90 years, 78.3% women) in this study. Of these participants, 41 (21.6%) reported falls in the preceding 12 months. People with any LBP (n = 101) and those with moderate-to-severe LBP (n = 45) had 2.7- and 3.7-times higher odds of recurrent falls, respectively. Sensitivity analyses revealed a strong correlation between moderate-to-severe LBP and recurrent falls.

CONCLUSION

Thorough investigation of LBP as a risk factor for recurrent falls in people with knee OA may provide a novel insight into the pathomechanics of recurrent falls in this population.

Towards classification criteria for early-stage knee osteoarthritis: A population-based study to enrich for progressors

OBJECTIVE

To facilitate a greater likelihood of favorable response to new disease-modifying therapies, recruitment of patients at an earlier stage of their disease into clinical trials may be an attractive strategy. Hence, there is a need to develop widely accepted classification criteria for early-stage knee osteoarthritis (OA). We have proposed a set of classification criteria for early-stage knee OA (2018 classification criteria) now being further refined. Here, we test the draft criteria for enrichment for clinical and structural progression.

DESIGN

Performance of the 2018 classification criteria for early stage knee OA was tested using data from the Osteoarthritis Initiative (OAI). The OAI comprises data of 4796 men and women aged 45-79 years with or at risk for knee OA at baseline. Based on the 2018 classification criteria, a knee with Kellgren & Lawrence (K&L) grade of 0-I, two out of four Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales equal or less than 85, and presence of at least one of joint line tenderness or crepitus, was considered as early-stage knee OA. Knees with K&L grade 0-I that did not fulfill the 2018 criteria, were considered as controls. Logistic regression analysis was used to evaluate the predictive performance of the criteria set for structural as well as clinical progression. We further explored the discriminatory capability of criteria by including the average KOOS₄ score, and relevant clinical examination findings such as the presence of effusion and/or Heberden's nodes.

RESULTS

We identified 1315 (27%) knees from OAI fulfilling the 2018 early-stage knee OA classification criteria. The female to male ratio was higher in the early knee OA group compared to controls. The early-stage knee OA group were on average slightly younger and had higher body mass index vs controls (mean [SD] age: 59.2 [8.9] years vs. 60.2 [9.1] and mean [SD] BMI 28.3 [7.0] vs. 26.8 [6.0]). By applying the 2018 criteria, there was a substantial enrichment compared to controls at 48 and 96 months for both structural (OR=1.1-1.4, and AUC=0.72-0.74) and clinical progressors (OR=2.1-2.5, 95% and AUC=0.66). Expanding the clinical examination findings by including joint effusion and/or Heberden's nodes improved the enrichment for both structural and clinical progressors (OR=4.2, 95% confidence interval=3.2-5.5 and OR=3.3, 95% confidence interval=2.8-3.5, respectively). Replacing scoring of the 4 separate KOOS domains by a KOOS₄ score performed comparably.

CONCLUSIONS

The proposed 2018 early-stage knee OA classification criteria showed encouraging performance characteristics with regard to an enrichment for structural and clinical progression using longitudinal OAI data. Our results indicate that the addition of clinical findings improves the performance of previous criteria to define early-stage disease and risk for progression.

Association between hip extensor muscle weakness and disability of activities of daily living in patients with early-stage knee osteoarthritis

INTRODUCTION

This study aimed to investigate the association between hip extensor muscle weakness and performance of activities of daily living (ADL) including stair ambulation, sit-to-stand (STS), and walking in patients with early-stage knee osteoarthritis (OA).

METHODS

Community-dwelling older individuals (age ≥ 65 years and Kellgren-Lawrence grade 1-2) were recruited in this cross-sectional study. The ability to perform stair ambulation, STS, and walking was measured using the Japanese Knee Osteoarthritis Measure. The maximum isometric knee extensor and hip extensor muscle strengths were evaluated. To investigate the association between hip extensor muscle strength and performance on ADL, a multivariate logistic analysis was conducted, adjusting for age, sex, and knee extensor muscle strength.

RESULTS

A total of 161 participants were included in this study. Multivariate logistic analysis revealed a significant association between lower hip extensor muscle strength and higher presence of difficulty in stair ambulation [odds ratio (OR), 0.33; 95% confidence interval (CI), 0.11. 0.98; p < 0.05] and STS (OR, 0.32; 95% CI, 0.11. 0.92; p < 0.05). No significant association between hip extensor muscle strength and difficulty in walking was observed (OR, 0.47; 95% CI, 0.14. 1.62; p = 0.23).

CONCLUSIONS

Hip extensor muscle weakness was associated with difficulty during stair ambulation and STS in patients with early-stage knee OA, after adjusting for knee extensor muscle strength. The results suggest that hip extensor muscle strength may be important to improve or maintain ADL in patients with early-stage knee OA.

Co-Design in the Development of a Mobile Health App for the Management of Knee Osteoarthritis by Patients and Physicians: Qualitative Study

BACKGROUND

Despite a doubling of osteoarthritis-targeted mobile health (mHealth) apps and high user interest and demand for health apps, their impact on patients, patient outcomes, and providers has not met expectations. Most health and medical apps fail to retain users longer than 90 days, and their potential for facilitating disease management, data sharing, and patient-provider communication is untapped. An important, recurrent criticism of app technology development is low user integration design. User integration ensures user needs, desires, functional requirements, and app aesthetics are responsive and reflect target user preferences.

OBJECTIVE

This study aims to describe the co-design process for developing a knee osteoarthritis minimum viable product (MVP) mHealth app with patients, family physicians, and researchers that facilitates guided, evidence-based self-management and patient-physician communication.

METHODS

Our qualitative co-design approach involved focus groups, prioritization activities, and a pre-post quality and satisfaction Kano survey. Study participants included family physicians, patient researchers and patients with knee osteoarthritis (including previous participants of related collaborative research), researchers, key stakeholders, and industry partners. The study setting was an academic health center in Southern Alberta.

RESULTS

Distinct differences exist between what patients, physicians, and researchers perceive are the most important, convenient, desirable, and actionable app functional requirements. Despite differences, study participants agreed that the MVP should be electronic, should track patient symptoms and activities, and include features customized for patient- and physician-identified factors and international guideline-based self-management strategies. Through the research process, participants negotiated consensus on their respective priority functional requirements. The highest priorities were a visual symptom graph, setting goals, exercise planning and daily tracking, and self-management strategies. The structured co-design with patients, physicians, and researchers established multiple collaborative processes, grounded in shared concepts, language, power, rationale, mutual learning, and respect for diversity and differing opinions. These shared team principles fostered an open and inclusive environment that allowed for effective conceptualization, negotiation, and group reflection, aided by the provision of tangible and ongoing support throughout the research process, which encouraged team members to question conventional thinking. Group-, subgroup-, and individual-level data helped the team reveal how and for whom perspectives about individual functional requirements changed or remained stable over the course of the study. This provided valuable insight into how and why consensus emerged, despite the presence of multiple and differing underlying rationales for functional requirement prioritization.

CONCLUSIONS

It is feasible to preserve the diversity of perspectives while negotiating a consensus on the core functional requirements of an mHealth prototype app for knee osteoarthritis management. Our study sample was purposely constructed to facilitate high co-design interactivity. This study revealed important differences between the patient, physician, and researcher preferences for functional requirements of an mHealth app that did not preclude the development of consensus.

Return to Sport Following High Tibial Osteotomy With Concomitant Osteochondral Allograft Transplantation

BACKGROUND

Young patients with symptomatic chondral defects in the medial compartment with varus malalignment may undergo opening wedge high tibial osteotomy (HTO) with concomitant osteochondral allograft transplantation (OCA) (HTO + OCA). Although patients have demonstrated favorable outcomes after HTO + OCA, limited information is available regarding return to sporting activities after this procedure.

PURPOSE

To evaluate (1) the timeline to return to sports (RTS), (2) patient satisfaction, and (3) reasons for discontinuing sporting activity after HTO + OCA, and to identify predictive factors of RTS.

STUDY DESIGN

Case series; level of evidence, 4.

METHODS

Consecutive patients who underwent HTO + OCA for varus deformity and medial femoral condyle focal chondral defects with a minimum 2-year follow-up were retrospectively reviewed. Patients completed a subjective sports questionnaire, satisfaction questionnaire, visual analog scale for pain, and Single Assessment Numerical Evaluation.

RESULTS

Twenty-eight patients with a mean age of 36.97 ± 7.52 years were included at mean follow-up of 6.63 ± 4.06 years. Fourteen patients (50.0%) required reoperation during the follow-up period, with 3 (10.7%) undergoing knee arthroplasty. Twenty-four patients participated in sports within 3 years before surgery, with 19 patients (79.2%) able to return to at least 1 sport at a mean 11.41 ± 6.42 months postoperatively. However, only 41.7% (n = 10) were able to return to their preoperative level. The most common reasons for sports discontinuation (n = 20; 83.3%) were a desire to prevent further damage to the knee (70.0%), persistent pain (55.0%), persistent swelling (30.0%), and fear (25.0%).

CONCLUSION

In young, active patients with varus deformity and focal medial femoral condyle chondral defects, HTO + OCA enabled 79.2% of patients to RTS by 11.41 ± 6.42 months postoperatively. However, only 41.7% of patients were able to return to their preinjury level or better. It is imperative that patients be appropriately educated to manage postoperative expectations regarding sports participation after HTO + OCA.

Return to Work Following High Tibial Osteotomy With Concomitant Osteochondral Allograft Transplantation

PURPOSE

To assess the timeline of return to work (RTW) following opening-wedge high tibial osteotomy (HTO) with concomitant osteochondral allograft transplantation (OCA) of the medial femoral condyle.

METHODS

Consecutive patients undergoing HTO + OCA due to focal chondral deficiency and varus deformity were retrospectively identified and reviewed at a minimum of 2 years following surgery. Patients completed a subjective work questionnaire, a visual analog scale for pain, Single Assessment Numerical Evaluation, and a satisfaction questionnaire.

RESULTS

Twenty-eight patients (average age: 36.0 ± 7.9 years) were included at 6.7 ± 4.1 years postoperatively. Twenty-six patients were employed before surgery and 25 patients (96.2%) returned to work following HTO + OCA. However, only 88.5% of patients were able to return to the same level of occupational intensity by 3.5 ± 2.9 months postoperatively. The rate of RTW to the same occupational intensity for sedentary, light, medium, and heavy intensity occupations was 100%, 100%, 88.9%, and 80% (P = .8), whereas the duration of RTW was 9.0 ± 7.1 months, 1.7 ± 1.4 months, 2.7 ± 0.9 months, and 4.2 ± 1.9 months (P = .006), respectively. Two patients (7.7%) underwent knee replacement by 5.3 ± 3.1 years postoperatively due to progression of osteoarthritis in the medial compartment.

CONCLUSIONS

In patients with focal chondral deficiency and varus deformity, HTO + OCA provides a high rate of RTW (96.2%) by 3.5 ± 2.9 months postoperatively. However, patients with greater-intensity occupations may take longer to return to work than those with less physically demanding occupations.

LEVEL OF EVIDENCE

IV, Retrospective Case Series.

Assessment of knee pain from MR imaging using a convolutional Siamese network

OBJECTIVES

It remains difficult to characterize the source of pain in knee joints either using radiographs or magnetic resonance imaging (MRI). We sought to determine if advanced machine learning methods such as deep neural networks could distinguish knees with pain from those without it and identify the structural features that are associated with knee pain.

METHODS

We constructed a convolutional Siamese network to associate MRI scans obtained on subjects from the Osteoarthritis Initiative (OAI) with frequent unilateral knee pain comparing the knee with frequent pain to the contralateral knee without pain. The Siamese network architecture enabled pairwise learning of information from two-dimensional (2D) sagittal intermediate-weighted turbo spin echo slices obtained from similar locations on both knees. Class activation mapping (CAM) was utilized to create saliency maps, which highlighted the regions most associated with knee pain. The MRI scans and the CAMs of each subject were reviewed by an expert radiologist to identify the presence of abnormalities within the model-predicted regions of high association.

RESULTS

Using 10-fold cross-validation, our model achieved an area under curve (AUC) value of 0.808. When individuals whose knee WOMAC pain scores were not discordant were excluded, model performance increased to 0.853. The radiologist review revealed that about 86% of the cases that were predicted correctly had effusion-synovitis within the regions that were most associated with pain.

CONCLUSIONS

This study demonstrates a proof of principle that deep learning can be applied to assess knee pain from MRI scans.

KEY POINTS

• Our article is the first to leverage a deep learning framework to associate MR images of the knee with knee pain. • We developed a convolutional Siamese network that had the ability to fuse information from multiple two-dimensional (2D) MRI slices from the knee with pain and the contralateral knee of the same individual without pain to predict unilateral knee pain. • Our model achieved an area under curve (AUC) value of 0.808. When individuals who had WOMAC pain scores that were not discordant for knees (pain discordance < 3) were excluded, model performance increased to 0.853.

Association of Knee Effusion Detected by Physical Examination With Bone Marrow Lesions: Cross-Sectional and Longitudinal Analyses of a Population-Based Cohort

OBJECTIVE

To determine the association of effusion detected by physical examination with the prevalence of bone marrow lesions (BMLs) on magnetic resonance imaging (MRI), and the incidence/progression of BMLs over 3 years in subjects with knee osteoarthritis.

METHODS

A population-based cohort with knee pain (n = 255) was assessed for effusion on physical examination. On MRI, BMLs were graded 0-3 (none, mild, moderate, severe), and incidence/progression was defined as a worsening of the sum of BML scores over 6 surfaces by ≥1 grade. We analyzed the full cohort and a mild disease subsample with a Kellgren/Lawrence (K/L) grade <3. Cross-sectional logistic and longitudinal exponential regression analyses were performed, adjusted for age, sex, body mass index (BMI) and pain. We calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for effusion detected by physical examination versus BMLs (prevalence and incidence/progression).

RESULTS

The weighted mean age was 56.7 years, the mean BMI was 26.5, 56.3% were women, 20.1% had effusion on physical examination, and 80.7% had a K/L grade <3. Effusion on physical examination was significantly associated with prevalent BMLs in the full cohort (odds ratio [OR] 6.10 [95% confidence interval (95% CI) 2.77-13.44]) and in the K/L grade <3 cohort (OR 6.88 [95% CI 2.76-17.15]). In the full cohort, sensitivity, specificity, PPV, and NPV were 34.6, 92.5, 79.9, and 62.1%, respectively, and in the K/L <3 cohort 31.7, 94.0, 75.5, and 70.1%, respectively. Longitudinally, effusion on physical examination was not significantly associated with BML incidence/progression in the full cohort (hazard ratio [HR] 1.83 [95% CI 0.95-3.52]) or in the K/L grade <3 cohort (HR 1.73 [95% CI 0.69-4.33]). In the two cohorts, sensitivity, specificity, PPV, and NPV were 32.0, 82.2, 42.2, and 74.9%, respectively, and 21.2, 85.6, 30.1, and 78.8% respectively.

CONCLUSION

BMLs on MRI can be predicted from physical examination effusion cross-sectionally, with a high PPV of 79.9%. Assessment for knee effusion on physical examination is useful for determining potential candidates with BMLs before costly MRI screening for recruitment into clinical trials.

Comparison of Diagnostic Accuracy of Physical Examination and MRI in the Most Common Knee Injuries

Purpose: This study evaluated the diagnostic accuracy of physical examination and magnetic resonance imaging (MRI) in knee injuries. Methods: Ninety-six patients at a regional hospital were included in the study. Each participant underwent a physical examination in which menisci and ACL were evaluated. Knee joint MRI was collected from each patient. Physical examination and MRI scans were then compared with knee arthroscopy findings as a golden standard for meniscal and ligamentous lesions. The data were analyzed and specificity and sensitivity were calculated and correlated on receiver operating characteristics (ROC) curves. Results: Knee arthroscopy diagnosed 32 total ACL ruptures, 45 medial meniscus and 17 lateral meniscus lesions. Three patients were diagnosed with bilateral meniscal lesions. The highest sensitivities were the McMurray test (87.5%) for medial meniscus (MM) and the Thessaly test (70%) for lateral meniscus (LM). The most sensitive ACL test was Lachman (84.5%), whereas, the pivot shift and Lelli tests were the most specific (98.5%). MRI was highly sensitive for MM (96%) with specificity of 52%. MRI showed lower sensitivity (70%) and higher specificity (85.5%) for LM. The specificity of MRI for ACL rupture was 92%, with sensitivity only 75%. Conclusion: McMurray and Apley tests for meniscal lesions seem the most appropriate in daily practice. A combination of lever signs, pivot shifts (PSs) and Lachman tests showed the best sensitivity and specificity in detecting ACL deficiency, and was superior to MRI.

Relationship Between Varus Thrust During Gait and Low Back Pain in Individuals With Knee Osteoarthritis

OBJECTIVE

To test the hypothesis that varus thrust visualized during gait is associated with a higher prevalence of low back pain (LBP) in individuals with knee osteoarthritis (OA).

METHODS

Individuals with knee OA (Kellgren/Lawrence grade ≥1) underwent a gait observation to assess varus thrust. The participants identified LBP and its severity using questionnaires. Logistic regression analyses were performed to examine the association between varus thrust and LBP.

RESULTS

We included 205 participants (mean age 68.19 years; 72.20% women). A total of 45 participants (22.0%) showed varus thrust in their painful knee, in whom 31 (68.89%) and 18 (40.00%) were identified as having any LBP and moderate-to-severe LBP (numerical rating scale ≥4 points), respectively. Patients with varus thrust demonstrated a 3.6-fold higher risk of the presence of moderate-to-severe LBP (95% confidence interval [95% CI] 1.62-8.10). In patients with LBP, the presence of varus thrust was associated with more severe LBP intensity (proportional odds ratio 2.25 [95% CI 1.02-4.96]).

CONCLUSION

This study highlights the novel relationship between varus thrust and LBP, which supports the idea of a biomechanical link, the so-called knee-spine syndrome. These findings provide new insight for clarifying the pathogenesis of LBP related to knee OA.

Psoriatic arthritis - new perspectives

Psoriatic arthritis (PsA) is a seronegative arthropathy with many clinical manifestations, and it may affect nearly a half of patients with psoriasis. PsA should be diagnosed as early as possible to slow down joint damage and progression of disability. To improve the diagnosis of PsA, physicians should look for peripheral inflammatory pain, axial inflammatory pain, dactylitis, and buttock and sciatic pain. In most patients with PsA, pharmacologic treatment with non-steroidal anti-inflammatory drugs, disease-modifying anti-rheumatic drugs, and biologic agents is effective. However, when pharmacological treatment fails, patients with PsA may benefit from orthopedic surgery, which can improve both joint function and quality of life. Total hip arthroplasty, total knee arthroplasty, and arthroscopic synovectomy of the knee are the most common surgical procedures offered to patients with PsA. The management of PsA requires the care of a multidisciplinary team, which should include dermatologists, rheumatologists, physiotherapists, and orthopedic surgeons.

Effects of interaction between varus thrust and ambulatory physical activity on knee pain in individuals with knee osteoarthritis: an exploratory study with 12-month follow-up

INTRODUCTION

This study aimed to examine the interaction effect between ambulatory physical activity (PA) and varus thrust on knee pain in individuals with knee osteoarthritis (OA).

METHOD

Subjects (n = 207; mean age: 73.1 years, 71.5% women) in orthopedic clinics with diagnosed knee OA (Kellgren/Lawrence grade ≥ 1) were enrolled in this 12-month observational cohort study. Participants underwent gait observation for varus thrust assessment and pedometer-based ambulatory PA measurements at baseline and 12-month follow-up. Knee pain intensity was assessed using the Japanese Knee Osteoarthritis Measure pain subscale as a primary outcome measure. Multiple linear regression analyses were performed to evaluate ambulatory PA-thrust interaction on knee pain intensity.

RESULTS

Ninety-two subjects (mean age, 73.4 years; 68.5% women) completed the 12-month follow-up assessment. Baseline ambulatory PA-thrust interaction was significant (P = 0.017) in the cross-sectional analysis, adjusting for covariates, which yielded R² = 0.310. Subgroup analysis showed that varus thrust was significantly associated with worse knee pain in subjects walking ≥ 5000 steps/day adjusting for covariates (beta: 7.94; 95% CI: 3.82, 12.1; P < 0.001) with a higher predictive ability (R² = 0.664). In contrast, ambulatory PA-thrust interaction in the longitudinal analysis showed no significant association with knee pain changes.

CONCLUSIONS

Ambulatory PA interacted with varus thrust in the association with knee pain, as coexisting high ambulatory PA and varus thrust had the strongest association with higher knee pain. Maximal pain relief effects might be achieved when both ambulatory PA and varus thrust are treated simultaneously, rather than treating each separately.

Trajectories of femorotibial cartilage thickness among persons with or at risk of knee osteoarthritis: development of a prediction model to identify progressors

OBJECTIVE

There is significant variability in the trajectory of structural progression across people with knee osteoarthritis (OA). We aimed to identify distinct trajectories of femorotibial cartilage thickness over 2 years and develop a prediction model to identify individuals experiencing progressive cartilage loss.

METHODS

We analysed data from the Osteoarthritis Initiative (OAI) (n = 1,014). Latent class growth analysis (LCGA) was used to identify trajectories of medial femorotibial cartilage thickness assessed on magnetic resonance imaging (MRI) at baseline, 1 and 2 years. Baseline characteristics were compared between trajectory-based subgroups and a prediction model was developed including those with frequent knee symptoms at baseline (n = 686). To examine clinical relevance of the trajectories, we assessed their association with concurrent changes in knee pain and incidence of total knee replacement (TKR) over 4 years.

RESULTS

The optimal model identified three distinct trajectories: (1) stable (87.7% of the population, mean change -0.08 mm, SD 0.19); (2) moderate cartilage loss (10.0%, -0.75 mm, SD 0.16) and (3) substantial cartilage loss (2.2%, -1.38 mm, SD 0.23). Higher Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) pain scores, family history of TKR, obesity, radiographic medial joint space narrowing (JSN) ≥1 and pain duration ≤1 year were predictive of belonging to either the moderate or substantial cartilage loss trajectory [area under the curve (AUC) 0.79, 95% confidence interval (CI) 0.74, 0.84]. The two progression trajectories combined were associated with pain progression (OR 1.99, 95% CI 1.34, 2.97) and incidence of TKR (OR 4.34, 1.62, 11.62).

CONCLUSIONS

A minority of individuals follow a progressive cartilage loss trajectory which was strongly associated with poorer clinical outcomes. If externally validated, the prediction model may help to select individuals who may benefit from cartilage-targeted therapies.

Trunk movement asymmetry associated with pain, disability, and quadriceps strength asymmetry in individuals with knee osteoarthritis: a cross-sectional study

OBJECTIVE

This study examined 1) the clinical relevance of trunk movement asymmetry, which was evaluated using a trunk-mounted inertial measurement unit (IMU), and 2) the relationship between trunk movement asymmetry and lower limb muscle strength asymmetry in individuals with knee osteoarthritis (OA).

DESIGN

One-hundred-thirty-one participants (mean age, 74.2 years; 71.8% female; Kellgren and Lawrence [K&L] grade ≥1) underwent gait analysis at their preferred pace for IMU-based measurement of trunk movement asymmetry (harmonic ratio [HR] and improved HR). The isometric strength of quadriceps and hip abductors was evaluated using a hand-held dynamometer. Pain and disability level were evaluated using a validated self-reported questionnaire. Multiple regression analyses with covariate adjustment were performed to examine the relationship between trunk movement asymmetry (independent variable) and pain, disability level, or muscle strength asymmetry (dependent variables).

RESULTS

Individuals with severe knee OA (K&L grade ≥3) had increased trunk movement asymmetry in the medio-lateral axis compared to those with a K&L grade of 1. Increased trunk movement asymmetry was associated with a greater knee pain and disability. The increased trunk movement asymmetry was significantly associated with an increase in the asymmetry of quadriceps strength, but not with asymmetry in the strength of hip abductor.

CONCLUSION

Our findings indicate that increased medio-lateral trunk movement asymmetry may be an indicator of impairment, rather than adaptation, in individuals with knee OA. This preliminary finding warrants validation by future study. Paying close attention to medio-lateral trunk movement asymmetry may be key to our understanding of OA-related pain and disability.

Long-term results of fresh osteochondral allografts and realignment osteotomy for cartilage repair in the knee

AIMS

The aim of this study was to report the outcome of femoral condylar fresh osteochondral allografts (FOCA) with concomitant realignment osteotomy with a focus on graft survivorship, complications, reoperation, and function.

PATIENTS AND METHODS

We identified 60 patients (16 women, 44 men) who underwent unipolar femoral condylar FOCA with concomitant realignment between 1972 and 2012. The mean age of the patients was 28.9 years (10 to 62) and the mean follow-up was 11.4 years (2 to 35). Failure was defined as conversion to total knee arthroplasty, revision allograft, or graft removal. Clinical outcome was evaluated using the modified Hospital for Special Surgery (mHSS) score.

RESULTS

A total of 14 grafts (23.3%) failed at a mean of 8.6 years (1.4 to 20.1). Graft survivorship was 87.3% (95% confidence interval (CI) 79.0 to 96.6), 85.0% (95% CI 75.8 to 95.3), 74.8% (95% CI 62.2 to 90.0), 65.2% (95% CI 49.9 to 85.2), and 59.8% (95% CI 43.5 to 82.1) at five, ten, 15, 20, and 25 years, respectively. A total of 23 patients (38.3%) developed complications, and 26 (43.3%) had a further operation. Persistent postoperative malalignment occurred more frequently in failed grafts (28.6% vs 4.3%; p = 0.023), and was a risk factor for graft failure (hazard ratio 6.55; 95% CI 1.61 27.71; p = 0.009). The mean mHSS score improved from 74.1 (40 to 91) preoperatively to 89.0 (66 to 100) at final follow-up (p < 0.001).

CONCLUSION

Femoral condylar FOCA with concomitant realignment osteotomy provides excellent long-term graft survival and reliable functional improvement. Persistent malalignment may increase the risk for graft failure.

Quadriceps Weakness and Risk of Knee Cartilage Loss Seen on Magnetic Resonance Imaging in a Population-based Cohort with Knee Pain

OBJECTIVE

To determine whether baseline quadriceps weakness predicts cartilage loss assessed on magnetic resonance imaging (MRI).

METHODS

Subjects aged 40-79 with knee pain (n = 163) were recruited from a random population sample and examined for quadriceps weakness with manual isometric strength testing, using a 3-point scoring system (0 = poor resistance, 1 = moderate resistance, 2 = full resistance), which was dichotomized as normal (grade 2) versus weak (grade 0/1). MRI of the more symptomatic knee was obtained at baseline and at mean of 3.3 years. Cartilage was graded 0-4 on MRI. Exponential regression analysis was used to evaluate whether quadriceps weakness was associated with whole knee cartilage loss, and in secondary analyses with compartment-specific cartilage loss, adjusted for age, sex, body mass index, Western Ontario and McMaster Universities Osteoarthritis Arthritis Index pain score, and baseline MRI cartilage score.

RESULTS

Of 163 subjects, 54% were female, with a mean age of 57.7 years. Quadriceps weakness was seen in 11.9% of the subjects. Weakness was a predictor of whole knee cartilage loss (HR 3.48, 95% CI 1.30-9.35). Quadriceps weakness was associated with cartilage loss in the medial tibiofemoral (TF) compartment (HR 4.60, 95% CI 1.25-17.02), while no significant association was found with lateral TF (HR 1.53, 95% CI 0.24-9.78) or patellofemoral compartment (HR 2.76, 95% CI 0.46-16.44).

CONCLUSION

In this symptomatic, population-based cohort, quadriceps weakness predicted whole knee and medial TF cartilage loss after 3 years. To our knowledge, this is the first study to show that a simple clinical examination of quadriceps strength can predict the risk of knee cartilage loss.

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.

Interaction between low back pain and knee pain contributes to disability level in individuals with knee osteoarthritis: a cross-sectional study

OBJECTIVE

To test the hypothesis that the interaction between low back pain (LBP) and knee pain intensity contributes to the disability level of individuals with knee osteoarthritis (OA).

DESIGN

Community-dwelling participants with knee OA (Kellgren/Lawrence [K/L] grade ≥1) were enrolled. LBP and its severity were identified using questionnaires. Knee pain severity and disability level were evaluated using the Japanese Knee Osteoarthritis Measure (JKOM) subscale. Multiple linear regression analyses were performed to examine the effect of the LBP-knee pain interaction, an independent variable, on disability, a dependent variable.

RESULTS

A total of 260 participants (age, 48-88 years; 77.7% women) were included. Of them, 151 (58.1%) had LBP. The LBP-knee pain interaction was significantly associated with disability after the adjustment for covariates. A post-hoc subgroup analysis revealed that the relationship between knee pain intensity and disability level was higher in individuals with LBP (beta: 0.621 points; 95% confidence interval [CI]: 0.511 to 0.731 points) than in those without LBP (beta: 0.402 points; 95% CI: 0.316 to 0.487 points).

CONCLUSIONS

LBP interacts with knee pain intensity and contributes to disability level in individuals with knee OA. Coexisting LBP and knee pain had a stronger impact on disability level than LBP or knee pain alone. These findings highlight the potential deteriorative effects of the LBP-knee interaction on disability. Maximal treatment effects for disability might be achieved when LBP and knee pain are targeted simultaneously, rather than separately.

Osteochondral Allograft Transplantation and Opening Wedge Tibial Osteotomy: Clinical Results of a Combined Single Procedure

Objective To evaluate the outcome of patients who have undergone simultaneous osteotomy and osteochondral allograft (OCA) transplantation. Our hypothesis is that use of high tibial osteotomy and fresh OCA in a combined procedure is safe and effective without increasing morbidity in comparison to OCA alone. Design A case series of 17 patients underwent tibial osteotomy and simultaneous OCA during a single surgery. Osteotomy was indicated when axial alignment was within the affected compartment. Patients had a minimum of 2 years of follow-up after surgery. The mean graft size was 8.7 cm², with 82% located on the medial femoral condyle alone and 18% involving the medial femoral condyle and one or more other sites. Data collection included demographics, osteotomy correction, graft site(s) and area, and clinical evaluation. Failure was defined as conversion to arthroplasty. Results Two of 17 patients (12%) failed at a mean of 9.3 years. The remaining 15 patients (88%) had intact allografts with mean survival of 8.1 years (SD 3.3). Five patients (29%) had an additional procedure, all undergoing osteotomy hardware removal. Of those with surviving allografts, mean pain and function scores improved significantly from the preoperative to postoperative assessment and International Knee Documentation Committee total scores improved significantly from 40.9 ± 15.4 preoperative to 75.5 ± 24.0 at latest follow-up ( P = 0.003); 92% of patients were satisfied with the results of the surgery. No postoperative complications occurred. Conclusion Combining high tibial osteotomy and OCA in properly selected patients is safe and effective.

Psychological health is associated with knee pain and physical function in patients with knee osteoarthritis: an exploratory cross-sectional study

Background

Depressive symptoms are a major comorbidity in older adults with knee osteoarthritis (OA). However, the type of activity-induced knee pain associated with depression has not been examined. Furthermore, there is conflicting evidence regarding the association between depression and performance-based physical function. This study aimed to examine (i) the association between depressive symptoms and knee pain intensity, particularly task-specific knee pain during daily living, and (ii) the association between depressive symptoms and performance-based physical function, while considering other potential risk factors, including bilateral knee pain and ambulatory physical activity.

Methods

Patients in orthopaedic clinics (n = 95; age, 61–91 years; 67.4% female) who were diagnosed with radiographic knee OA (Kellgren/Lawrence [K/L] grade ≥ 1) underwent evaluation of psychological health using the Geriatric Depression Scale (GDS). Knee pain and physical function were assessed using the Japanese Knee Osteoarthritis Measure (JKOM), 10-m walk, timed up and go (TUG), and five-repetition chair stand tests.

Results

Ordinal logistic regression analysis showed that depression, defined as a GDS score ≥ 5 points, was significantly associated with a worse score on the JKOM pain-subcategory and a higher level of task-specific knee pain intensity during daily living, after being adjusted for age, sex, body mass index (BMI), K/L grade, and ambulatory physical activity. Furthermore, depression was significantly associated with a slower gait velocity and a longer TUG time, after adjusting for age, sex, BMI, K/L grade, presence of bilateral knee pain, and ambulatory physical activity.

Conclusions

These findings indicate that depression may be associated with increased knee pain intensity during daily living in a non-task-specific manner and is associated with functional limitation in patients with knee OA, even after controlling for covariates, including bilateral knee pain and ambulatory physical activity.

Electronic supplementary material

The online version of this article (10.1186/s40359-018-0234-3) contains supplementary material, which is available to authorized users.

Varus thrust visualized during gait was associated with inverted foot in patients with knee osteoarthritis: An exploratory study

The foot is speculated to play a role in knee joint kinematics. This exploratory cross-sectional study examined the association between static foot posture and the presence of varus thrust visualized during gait in patients with medial knee osteoarthritis (OA). Patients (n = 88 patients and 134 knees; age, 61-91 years; 68.2% female) with Kellgren/Lawrence (K/L) grade ≥1 in the medial compartment were included in this study and underwent gait observation for varus thrust. These patients' three-dimensional static foot posture while standing was evaluated and their tibiofemoral joint K/L grades and anatomical axis angles were also assessed as covariates. Knees with varus thrust (22 knees, 16.4%) on average had a 4° more inverted calcaneus relative to the floor than those without varus thrust (P < 0.001). A logistic regression analysis showed that an increased calcaneus inversion angle was significantly associated with higher odds of the presence of varus thrust with adjustments for age, sex, body mass index, K/L grade, and anatomical axis angle. The other predictors, such as navicular height, navicular height/foot length, and rearfoot angle relative to the lower leg, were not significantly associated with varus thrust. These results suggest that patients with varus thrust had a different static rearfoot posture as compared with those without varus thrust, a finding that may indicate an important role of static rearfoot posture in the pathogenesis of varus thrust. Furthermore, investigating the potential influence of foot posture on the efficacy of biomechanical interventions, such as lateral wedge insole use, on varus thrust would be of particular interest in the further studies.

Association of bilateral flat feet with knee pain and disability in patients with knee osteoarthritis: A cross-sectional study

This cross-sectional study examined the relationship of flat feet with knee pain, disability, and physical performance in patients with knee osteoarthritis (OA). Orthopedic clinic participants (n = 95; age 61-91 years; 68.4% women) with Kellgren-Lawrence (K/L) grade ≥1 in the medial compartment underwent evaluation of navicular height and foot length for flat feet. Knee pain intensity, disability, and physical performance were evaluated using the Japanese Knee Osteoarthritis Measure, 10-m walk, timed up and go, and five-repetition chair stand tests. Of the 95 enrolled patients, 24 (25.3%) had bilateral flat feet, and significantly higher knee pain compared to patients with no flat feet (11.3 ± 8.23 points vs. 6.58 ± 6.37 points; p = 0.043). A ordinal logistic regression analysis showed that bilateral flat feet were significantly associated with increased knee pain (proportional odds ratio: 5.48, 95% confidence interval: 1.96, 15.3; p = 0.001) compared with no flat feet, adjusted for age, sex, body mass index, and tibiofemoral joint K/L grade, which is consistent across various different cutoffs of the definition of flat feet. Physical performance was similar between patients with and without bilateral flat feet. The presence of unilateral flat feet was not significantly associated with any outcome measures. These findings indicate that bilateral, but not unilateral, flat feet are associated with worse knee pain. A prospective study investigating a causal relationship between bilateral flat feet posture and knee pain as well as disability would be of particular interest to verify the potential adverse effect of altered foot posture. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2490-2498, 2017.

Association of varus thrust with prevalent patellofemoral osteoarthritis: A cross-sectional study

This cross-sectional study investigated (i) the association of varus thrust during gait with the presence of patellofemoral osteoarthritis (PFOA) in patients with medial knee osteoarthritis (OA) and (ii) patellar alignment in the knees with varus thrust. Participants from orthopedic clinics (n=171; mean age, 73.4 years; 71.9% female) diagnosed with radiographic medial knee OA (Kellgren/Lawrence [K/L] grade ≥1) were included in this study, and underwent gait observation for varus thrust assessment using 2D video analysis. A radiographic skyline view was used to assess the presence of medial PFOA using the grading system from the Osteoarthritis Research Society International Atlas. The tibiofemoral joint K/L grade, patellar alignment (i.e., lateral shift and tilting angle), and knee pain intensity were also evaluated as covariates. Thirty-two (18.7%) of 171 patients exhibited varus thrust and they presented significantly higher knee pain (46.0±3.04mm vs. 32.4±2.73mm; P=0.024), a lower patellar tilting angle (P=0.024), and a higher prevalence of PFOA compared with those without varus thrust. A logistic regression analysis with adjustment of covariates showed that varus thrust was significantly associated with higher odds of the presence of mixed and medial PFOA, and trended to significantly associate with any PFOA, including lateral PFOA. This indicates that varus thrust was associated with PFOA in a compartment-nonspecific manner in patients with medial knee OA. Varus thrust may represent a clinical disease feature of more advanced and multicompartmental disease.

Association of frontal plane knee alignment with foot posture in patients with medial knee osteoarthritis

Background

To examine the association of radiographic frontal plane knee alignment with three-dimensional foot posture in patients with medial knee osteoarthritis (OA).

Methods

Participants in orthopedic clinics with Kellgren/Lawrence (K/L) grade ≥1 (88 patients and 88 knees; age, 61–91 years; 65.9% female) were enrolled. An anteroposterior radiographic view was used to assess the anatomical axis angle (AAA) after subtracting a sex-specific correction factor. The three-dimensional foot posture was also evaluated.

Results

Multiple regression analyses showed that increased corrected AAA (i.e., valgus direction) was independently associated with a decrease in the hallux valgus angle (regression coefficient: −0.40 per degree, 95% confidence interval [CI]: −0.72, −0.09; P = 0.013) and increase in the pronation angle of the calcaneus relative to floor (regression coefficient: 0.33 per degree, 95% CI: 0.10, 0.56; P = 0.005) adjusted for age, sex, and body mass index. The relationship between the corrected AAA and hallux valgus angle strengthened (regression coefficient: −0.60 per degree, 95% CI: −1.08, −0.13; P = 0.014) in varus-aligned knees examined separately (63 knees). The other foot postures (navicular height, navicular height/foot length, and rearfoot angle) were not significantly associated with corrected AAA.

Conclusions

Radiographic frontal plane knee alignment was associated with hallux valgus angle and calcaneus angle relative to the floor in patients with medial knee OA, particularly in varus-aligned knees. These results indicate a connection between altered frontal knee alignment and foot posture, which may be helpful in understanding the pathogenesis of altered foot posture observed in patients with knee OA.

Associations between MRI features versus knee pain severity and progression: Data from the Vancouver Longitudinal Study of Early Knee Osteoarthritis

Objective

To determine associations between features of osteoarthritis (OA) on MRI and knee pain severity and knee pain progression.

Design

Baseline, 3.3- and 7.5-year assessments were performed for 122 subjects with baseline knee pain (age 40–79), sample-weighted for population (with knee pain) representativeness. MRIs were scored for: osteophytes (0:absent to 3:large); cartilage (0:normal to 4:full thickness defect; 0/1 collapsed); subchondral sclerosis (0:none to 3:>50% of site), subchondral cyst (0:absent to 3:severe), bone marrow lesions (0:none to 3:≥50% of site); and meniscus (0:normal to 3:maceration/resection), in 6–8 regions each. Per feature, scores were averaged across regions. Effusion/synovitis (0:absent to 3:severe) was analyzed as ≥2 vs. <2.

Linear models predicted WOMAC knee pain severity (0–100), and binary models predicted 10+ (minimum perceptible clinical improvement [MPCI]) and 20+ (minimum clinically important difference [MCID]) increases. Models were adjusted for age, sex, BMI (and follow-up time for longitudinal models).

Results

Pain severity was associated with osteophytes (7.17 per unit average; 95% CI = 3.19, 11.15) and subchondral sclerosis (11.03; 0.68, 21.39). MPCI-based pain increase was associated with osteophytes (odds ratio per unit average 3.20; 1.36, 7.55), subchondral sclerosis (5.69; 1.06, 30.44), meniscal damage (1.68; 1.08, 2.61) and effusion/synovitis ≥2 (2.25; 1.07, 4.71). MCID-based pain increase was associated with osteophytes (3.79; 1.41, 10.20) and cartilage defects (2.42; 1.24, 4.74).

Conclusions

Of the features investigated, only osteophytes were consistently associated with pain cross-sectionally and longitudinally in all models. This suggests an important role of bone in early knee osteoarthritis.

Ability of a Urine Assay of Type II Collagen Cleavage by Collagenases to Detect Early Onset and Progression of Articular Cartilage Degeneration: Results from a Population-based Cohort Study

OBJECTIVE

To evaluate the association of a sandwich assay for cartilage collagenase-mediated degradation, the C2C human urine sandwich assay (IB-C2C-HUSA), with early and late knee cartilage pathology and with progression of cartilage damage.

METHODS

A population-based cohort with knee pain, age 40-79 years, was evaluated at baseline (n = 253) and after mean 3.3 years (n = 161). We evaluated the IB-C2C-HUSA and a related competitive inhibition assay (C2C). The C2C assay was applied to serum (sC2C) and urine (uC2C). Based on knee radiographs and magnetic resonance imaging (MRI), 3 subgroups [no cartilage pathology, preradiographic cartilage pathology, and radiographic osteoarthritis (ROA)] were evaluated cross-sectionally for association with biomarker levels. Longitudinally, we evaluated whether baseline assays predict subsequent progression of cartilage degeneration, defined by MRI cartilage loss.

RESULTS

Cross-sectionally, statistically significant differences were seen in the 3 subgroups for IB-C2C-HUSA (p < 0.001), with the highest levels seen in ROA, and for sC2C (p = 0.023), while no differences were seen for uC2C (p = 0.501). Baseline IB-C2C-HUSA levels were higher in progressors vs nonprogressors (p = 0.003). In logistic regression analysis, only baseline IB-C2C-HUSA was associated with an increased risk of progression of cartilage damage (OR 1.78, 95% CI 1.03-3.09).

CONCLUSION

The IB-C2C-HUSA degradation assay detects the generation of a pathology-related cartilage collagen peptide(s) that increase(s) with onset of degeneration of knee articular cartilage. The baseline values are associated with progression of cartilage degeneration over 3 subsequent years. This assay may have value in clinical OA trials. Further, it points to collagenase activity as a therapeutic target for controlling degeneration of articular cartilage.

Can Signal Abnormalities Detected with MR Imaging in Knee Articular Cartilage Be Used to Predict Development of Morphologic Cartilage Defects? 48-Month Data from the Osteoarthritis Initiative

Purpose To determine the incidence with which morphologic articular cartilage defects develop over 48 months in cartilage with signal abnormalities at baseline magnetic resonance (MR) imaging in comparison with the incidence in articular cartilage without signal abnormalities at baseline. Materials and Methods The institutional review boards of all participating centers approved this HIPAA-compliant study. Right knees of 90 subjects from the Osteoarthritis Initiative (mean age, 55 years ± 8 [standard deviation]; 51% women) with cartilage signal abnormalities but without morphologic cartilage defects at 3.0-T MR imaging and without radiographic osteoarthritis (Kellgren-Lawrence score, 0-1) were frequency matched for age, sex, Kellgren-Lawrence score, and body mass index with right knees in 90 subjects without any signal abnormalities or morphologic defects in the articular cartilage (mean age, 54 years ± 5; 51% women). Individual signal abnormalities (n = 126) on intermediate-weighted fast spin-echo MR images were categorized into four subgrades: subgrade A, hypointense; subgrade B, inhomogeneous; subgrade C, hyperintense; and subgrade D, hyperintense with swelling. The development of morphologic articular cartilage defects (Whole-Organ MR Imaging Score ≥2) at 48 months was analyzed on a compartment level and was compared between groups by using generalized estimating equation logistic regression models. Results Cartilage signal abnormalities were more frequent in the patellofemoral joint than in the tibiofemoral joint (59.5% vs 39.5%). Subgrade A was seen more frequently than were subgrades C and D (36% vs 22%). Incidence of morphologic cartilage defects at 48 months was 57% in cartilage with baseline signal abnormalities, while only 4% of compartments without baseline signal abnormalities developed morphologic defects at 48 months (all compartments combined and each compartment separately, P < .01). The development of morphologic defects was not significantly more likely in any of the subgrades (P = .98) and was significantly associated with progression of bone marrow abnormalities (P = .002). Conclusion Knee cartilage signal abnormalities detected with MR imaging are precursors of morphologic defects with osteoarthritis and may serve as imaging biomarkers with which to assess risk for cartilage degeneration. (©) RSNA, 2016.

Is loss in femorotibial cartilage thickness related to severity of contra-lateral radiographic knee osteoarthritis?--longitudinal data from the Osteoarthritis Initiative

OBJECTIVE

Anti-catabolic disease modifying drugs (DMOADs) aim to reduce cartilage loss in knee osteoarthritis (KOA). Testing such drugs in clinical trials requires sufficient rates of loss in the study participants to occur, preferably at a mild disease stage where cartilage can be preserved. Here we analyze a "progression" model in mild radiographic KOA (RKOA), based on contra-lateral radiographic status.

METHODS

We studied 837 participants (62.4 ± 9 yrs; 30 ± 4.9 kg/m²; 61.8% women) from the Osteoarthritis Initiative (OAI) with mild to moderate RKOA (Kellgren Lawrence grade [KLG] 2-3) and with/without Osteoarthritis Research Society International (OARSI) atlas radiographic joint space narrowing (JSN). These had quantitative measurements of subregional femorotibial cartilage thickness from magnetic resonance imaging (MRI) at baseline and 1-year follow-up. They were stratified by contra-lateral knee status: no (KLG 0/1), definite (KLG2) and moderate RKOA (KLG 3/4).

RESULTS

KLG2 knees with JSN and moderate contra-lateral RKOA had (P = 0.008) greater maximum subregional cartilage loss -220 μm [95% confidence interval (CI) -255, -184 μm] than those without contra-lateral RKOA -164 μm [-187, -140 μm]. Their rate of subregional cartilage loss was similar and not significantly different (P = 0.61) to that in KLG 3 knees without contra-lateral RKOA (-232 μm; [-266; -198 μm]). The effect of contra-lateral RKOA status was less in KLG2 knees without JSN, and in KLG3 knees.

CONCLUSION

KLG2 knees with JSN and moderate contra-lateral RKOA, display relatively high rates of subregional femorotibial cartilage loss, despite being at a relatively mild stage of RKOA. They may therefore provide a unique opportunity for recruitment in clinical trials that explore the efficacy of anti-catabolic DMOADs on structural progression.

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

OBJECTIVE

Little is known about early knee osteoarthritis (OA). The significance of lesions on magnetic resonance imaging (MRI) in older persons without radiographic OA is unclear. Our objectives were to determine the extent of tissue pathology by MRI and evaluate its significance by testing the following hypotheses: cartilage damage, bone marrow lesions, and meniscal damage are associated with prevalent frequent knee symptoms and incident persistent symptoms; bone marrow lesions and meniscal damage are associated with incident tibiofemoral (TF) cartilage damage; and bone marrow lesions are associated with incident patellofemoral (PF) cartilage damage.

METHODS

In a cohort study of 849 Osteoarthritis Initiative (OAI) participants who had a bilateral Kellgren/Lawrence (K/L) score of 0, we assessed cartilage damage, bone marrow lesions, and meniscal damage using the MRI OA Knee Score, as well as prevalent frequent knee symptoms, incident persistent symptoms, and incident cartilage damage. Multiple logistic regression (one knee per person) was used to evaluate associations between MRI lesions and each of these outcomes.

RESULTS

Of the participants evaluated, 76% had cartilage damage, 61% had bone marrow lesions, 21% had meniscal tears, and 14% had meniscal extrusion. Cartilage damage (any; TF and PF), bone marrow lesions (any; TF and PF), meniscal extrusion, and body mass index (BMI) were associated with prevalent frequent symptoms. Cartilage damage (isolated PF; TF and PF), bone marrow lesions (any; isolated PF; TF and PF), meniscal tears, and BMI were associated with incident persistent symptoms. Hand OA, but no individual lesion type, was associated with incident TF cartilage damage, and bone marrow lesions (any; any PF) with incident PF damage. Having more lesion types was associated with a greater risk of outcomes.

CONCLUSION

MRI-detected lesions are not incidental and may represent early disease in persons at increased risk of knee OA.

The relationship between subchondral sclerosis detected with MRI and cartilage loss in a cohort of subjects with knee pain: the knee osteoarthritis progression (KOAP) study

PURPOSE

To assess the association between subchondral sclerosis detected at baseline with MRI and cartilage loss over time in the same region of the knee in a cohort of subjects with knee pain.

METHODS

163 subjects with knee pain participated in a longitudinal study to assess knee osteoarthritis progression (KOAP). Subjects received baseline knee radiographs as well as baseline and 3-year follow-up MRI examinations. Baseline subchondral sclerosis and bone marrow lesions (BMLs) were scored semiquantitatively on MRI in each region from 0 to 3. Cartilage morphology at baseline and follow-up was scored semiquantitatively from 0 to 4. The association between baseline subchondral sclerosis and cartilage loss in the same region of the knee was evaluated using logistic regression, adjusting the results for age, gender, body mass index, and the presence of concomitant BMLs.

RESULTS

The prevalence of subchondral sclerosis detected by MRI in the regions of the knee varied between 1.6% (trochlea) and 17% (medial tibia). The occurrence of cartilage loss over time in regions varied between 6% (lateral tibia) and 13.1% (medial femur). The prevalence of radiographically-detected subchondral sclerosis in compartments varied from 2.9% (patellofemoral) to 14.2% (medial tibiofemoral). In logistic regression models, there were no significant associations between baseline subchondral sclerosis detected by MRI and cartilage loss in the same region of the knee.

CONCLUSION

Baseline subchondral sclerosis as detected by MRI did not increase the risk of cartilage loss over time.

Does moderate or severe nonspecific knee injury affect radiographic osteoarthritis incidence and progression?

Background

Knee injuries can lead to radiographic osteoarthritis (ROA). Injuries may be “specific” (SI) including ligament or meniscal tears or patellar trauma, or “nonspecific” (NSI). Our objective is to understand the effect of knee NSI on ROA incidence and progression.

Methods

163 people (sample-weighted for population representativeness) aged 40+ with history of knee pain had radiographs assessed on Kellgren Lawrence (KL) grade (0/1 collapsed) at baseline and follow-up (median 3.2 years apart). Progression was an increase in KL score. SIs and NSIs were labeled “severe” (walking aid for ≥1 week) or “moderate”. One model treated SI and NSI as dichotomous (yes/no), and another as trichotomous (none/moderate/severe). Models were adjusted for age, sex, BMI, KL grade and follow-up time.

Results

SI/NSI history was none, moderate (7.8/24.4%) or severe (11.0/10.8%). Duration at baseline since SI/NSI ranged from <1 year to several decades (SI/NSI mean 4.6/6.5 years). SI was significantly associated with ROA incidence and progression (odds ratio (OR) = 2.90; 95% CI = 1.04, 8.09), but NSI showed no significant effect (OR = 1.36; 95% CI = 0.61, 3.02). In the trichotomous model, severe SI was significant (OR = 4.35, 95% CI = 1.26, 15.02), while moderate SI was not (OR = 1.51, 95% CI = 0.33, 6.84). NSI showed no effect: moderate OR = 1.51, 95% CI = 0.61, 3.74; severe OR = 0.90, 95% CI = 0.24, 3.40. This study had 80% power to detect an NSI OR of 2.9.

Conclusion

We find no evidence that history of NSI affects knee ROA incidence and progression in a population with knee pain, adjusting for SI, age, sex, BMI, KL grade and follow-up time.

T1-weighted sodium MRI of the articulator cartilage in osteoarthritis: a cross sectional and longitudinal study

Structural magnetic resonance imaging (MRI) has shown great utility in diagnosing soft tissue burden in osteoarthritis (OA), though MRI measures of cartilage integrity have proven more elusive. Sodium MRI can reflect the proteoglycan content of cartilage; however, it requires specialized hardware, acquisition sequences, and long imaging times. This study was designed to assess the potential of a clinically feasible sodium MRI acquisition to detect differences in the knee cartilage of subjects with OA versus healthy controls (HC), and to determine whether longitudinal changes in sodium content are observed at 3 and 6 months. 28 subjects with primary knee OA and 19 HC subjects age and gender matched were enrolled in this ethically-approved study. At baseline, 3 and 6 months subjects underwent structural MRI and a 0.4ms echo time 3D T1-weighted sodium scan as well as the knee injury and osteoarthritis outcome score (KOOS) and knee pain by visual analogue score (VAS). A standing radiograph of the knee was taken for Kellgren-Lawrence (K-L) scoring. A blinded reader outlined the cartilage on the structural images which was used to determine median T1-weighted sodium concentrations in each region of interest on the co-registered sodium scans. VAS, K-L, and KOOS all significantly separated the OA and HC groups. OA subjects had higher T1-weighted sodium concentrations, most strongly observed in the lateral tibial, lateral femoral and medial patella ROIs. There were no significant changes in cartilage volume or sodium concentration over 6 months. This study has shown that a clinically-feasible sodium MRI at a moderate 3T field strength and imaging time with fluid attenuation by T1 weighting significantly separated HCs from OA subjects.