Incidence, progression and sequence of development of radiographic knee osteoarthritis in a symptomatic population

Radiomics analysis of patellofemoral joint improves knee replacement risk prediction: Data from the Multicenter Osteoarthritis Study (MOST)

Objective

Knee replacement (KR) is the last-resort treatment for knee osteoarthritis. Although radiographic evidence of tibiofemoral joint has been widely adopted for prognostication, patellofemoral joint has gained little attention and may hold additional value for further improvements. We aimed to quantitatively analyse patellofemoral joint through radiomics analysis of lateral view radiographs for improved KR risk prediction.

Design

From the Multicenter Osteoarthritis Study dataset, we retrospectively retrieved the initial-visit lateral left knee radiographs of 2943 patients aged 50 to 79. They were split into training and test cohorts at a 2:1 ratio. A comprehensive set of radiomic features were extracted within the best-performing subregion of patellofemoral joint and combined into a radiomics score (RadScore). A KR risk score, derived from Kellgren-Lawrence grade (KLG) of tibiofemoral joint and RadScore of patellofemoral joint, was developed by multivariate Cox regression and assessed using time-dependent area under receiver operating characteristic curve (AUC).

Results

While patellofemoral osteoarthritis (PFOA) was insignificant during multivariate analysis, RadScore was identified as an independent risk factor (multivariate Cox p-value < 0.001) for KR. The subgroup analysis revealed that RadScore was particularly effective in predicting rapid progressor (KR occurrence before 30 months) among early- (KLG < 2) and mid-stage (KLG ​= ​2) patients. Combining two joints radiographic information, the AUC reached 0.89/0.87 for predicting 60-month KR occurrence.

Conclusions

The RadScore of the patellofemoral joint on lateral radiographs emerges as an independent prognostic factor for improving KR prognosis prediction. The KR risk score could be instrumental in managing progressive knee osteoarthritis interventions.

Multiple intra-articular injections of autologous stromal vascular fractions for the treatment of multicompartmental osteoarthritis in both the tibiofemoral and patellofemoral joint: a single-blind randomized controlled study

BACKGROUND

Multicompartmental osteoarthritis (MOA) in both tibiofemoral and patellofemoral joints is a more commonly occurring, but neglected, clinical condition, and we examined the short-term safety and efficacy of autologous stromal vascular fractions (SVFs) for MOA using a single-blind, prospective, randomized, placebo-controlled trial.

METHODS

Seventy MOA patients were recruited and randomly assigned to the SVF group and hyaluronic acid (HA) group (control group). The scores of visual analog scale, the Western Ontario and McMaster University Osteoarthritis Index, and the Samsung Medical Center patellofemoral scoring system were assessed and compared between the two groups 3, 6 and 12 months after treatment.

RESULTS

The SVF group had significantly better visual analog scale scores than the HA group at 6 and 12 months after treatment and had better Western Ontario and McMaster University Osteoarthritis Index scores than the HA group only at 6 months after treatment. For Samsung Medical Center patellofemoral scoring system of the patellofemoral joint, the SVF group had significantly better scores than the control group at all postoperative time points. The proportion of patients whose visual analog scale and Western Ontario and McMaster University Osteoarthritis Index scores were above the minimal clinically important improvement was higher in the SVF group than in the HA group in the majority of assessments. The improvement of bone marrow by SVF treatment was significantly better than that of the HA group as observed by pre- and postoperative Magnetic resonance imaging (MRI).

CONCLUSIONS

Multiple intra-articular injection of autologous SVF reduces pain and improves function in the short term in patients with early or midstage MOA. However, there was heterogeneity in the improvement of overall knee and isolated patellofemoral joint after treatment.

Deep Learning for Predicting Progression of Patellofemoral Osteoarthritis Based on Lateral Knee Radiographs, Demographic Data, and Symptomatic Assessments

OBJECTIVE

 In this study, we propose a novel framework that utilizes deep learning and attention mechanisms to predict the radiographic progression of patellofemoral osteoarthritis (PFOA) over a period of 7 years.

MATERIAL AND METHODS

 This study included subjects (1,832 subjects, 3,276 knees) from the baseline of the Multicenter Osteoarthritis Study (MOST). Patellofemoral joint regions of interest were identified using an automated landmark detection tool (BoneFinder) on lateral knee X-rays. An end-to-end deep learning method was developed for predicting PFOA progression based on imaging data in a five-fold cross-validation setting. To evaluate the performance of the models, a set of baselines based on known risk factors were developed and analyzed using gradient boosting machine (GBM). Risk factors included age, sex, body mass index, and Western Ontario and McMaster Universities Arthritis Index score, and the radiographic osteoarthritis stage of the tibiofemoral joint (Kellgren and Lawrence [KL] score). Finally, to increase predictive power, we trained an ensemble model using both imaging and clinical data.

RESULTS

 Among the individual models, the performance of our deep convolutional neural network attention model achieved the best performance with an area under the receiver operating characteristic curve (AUC) of 0.856 and average precision (AP) of 0.431, slightly outperforming the deep learning approach without attention (AUC = 0.832, AP = 0.4) and the best performing reference GBM model (AUC = 0.767, AP = 0.334). The inclusion of imaging data and clinical variables in an ensemble model allowed statistically more powerful prediction of PFOA progression (AUC = 0.865, AP = 0.447), although the clinical significance of this minor performance gain remains unknown. The spatial attention module improved the predictive performance of the backbone model, and the visual interpretation of attention maps focused on the joint space and the regions where osteophytes typically occur.

CONCLUSION

 This study demonstrated the potential of machine learning models to predict the progression of PFOA using imaging and clinical variables. These models could be used to identify patients who are at high risk of progression and prioritize them for new treatments. However, even though the accuracy of the models were excellent in this study using the MOST dataset, they should be still validated using external patient cohorts in the future.

Is muscle activation diverse in females with isolated patellofemoral osteoarthritis contrasted with age-matched healthy controls during stair descent task?

Background: Patellofemoral osteoarthritis (PF OA) is exceptionally predominant and limiting. However, little is known about the risk factors that contribute to its onset and progression. Purpose: The aim of this study was to decide if women with PF OA descend stairs using different muscular activation strategies compared to similarly aged healthy controls. Methods: Thirty-one women with isolated PF OA and 11 similarly aged healthy women took part in this study. The activation onset and duration of PF OA in vastus medialis oblique (VMO), vastus lateralis (VL), gluteus medius (GM), transversus abdominis (TrA), and multifidus muscles were evaluated during the stair descent task using surface electromyography (EMG). Results: There was a non-significant difference between women with PF OA and healthy controls regarding all tested variables, except for the GM activation onset that was significantly delayed in women with PF OA, with the p-value of 0.011. Conclusion: The causes of PF OA differ and might not always be due to a lack of quadriceps strength or VMO activation deficiency, and prospective longitudinal studies are required to confirm this assumption.

MRI-Based Radiomics and Delta-Radiomics Models of the Patella Predict the Radiographic Progression of Osteoarthritis: Data From the FNIH OA Biomarkers Consortium

RATIONALE AND OBJECTIVES

To analyse the MRI-based radiomics and delta-radiomics features to establish radiomics models for predicting the radiographic progression of osteoarthritis (OA).

MATERIALS AND METHODS

The data used in this research come from the dataset of the FNIH Biomarker Consortium Project within the Osteoarthritis Initiative (OAI). 565 participants randomly divided into training and validation groups at a 7:3 ratio. The training cohort consisted of 395 participants and included 202 cases. The validation cohort consisted of 170 participants and included 87 cases. Least absolute shrinkage and selection operator (LASSO) was used for feature selection. Support vector machine (SVM) was used to establish radiomics models and clinical and biomarker models for predicting the radiographic progression of OA. The predictive ability of the model was evaluated by the area under the curve (AUC).

RESULTS

The baseline, 24 M, Delta, and two combination radiomics models (Baseline and Delta, 24 M and Delta) all showed good predictive performance in the training and validation cohorts, with the combination model exhibiting the best performance. In the training cohort, the AUCs were 0.851 (95% CI: 0.812-0.890), 0.825 (95% CI: 0.784-0.865), 0.804 (95% CI: 0.761-0.847), 0.892 (95% CI: 0.860-0.924) and 0.884 (95% CI: 0.851-0.917), respectively. The AUCs in the validation cohort were 0.741 (95% CI: 0.667-0.814), 0.786 (95% CI: 0.716-0.856), 0.745 (95% CI: 0.671-0.819), 0.781 (95% CI: 0.711-0.851) and 0.802 (95% CI: 0.736-0.869), respectively. As compared, the clinical and biomarker models have AUC < 0.74. The DeLong test showed that the predictive performance of the radiomics models in the training and validation cohorts was significantly better than that of the clinical and biomarker models (P < 0.001).

CONCLUSION

The MRI-based radiomics models of the patella all showed good predictive performance performed better than the clinical and biomarker models in predicting the radiographic progression of OA. Delta radiomics can improve the predictive performance of the single time model, the combined model of 24 M and Delta provided the best predictive performance.

Global research trends and hotspots in patellofemoral pain syndrome from 2000 to 2023: a bibliometric and visualization study

Background

Patellofemoral pain syndrome (PFPS) is a prevalent condition in sports medicine, and as sports competitions become more popular, the incidence of sports injuries is on the rise. Despite the increasing research on PFPS, there remains a lack of bibliometric analyses on this topic. The aim of this study was to identify the research hotspots and trends in the field of PFPS by reviewing 23 years of literature in this field.

Methods

By analyzing the literature on PFPS research from 2000 to 2023 in the core dataset of the Web of Science database and utilizing bibliometric tools like CiteSpace 6.1, VOSviewer 1.6.18, R-bibliometrix 4.6.1, Pajek 5.16, and Scimago Graphica 1.0.26, our aim was to gain insights into the current status and key areas of PFPS research. The study examined various aspects including the number of publications, countries, institutions, journals, authors, collaborative networks, keywords, and more. Through the visualization of relevant data, we also attempted to forecast future trends in the field.

Results

There were 2,444 publications were included in this visualization study, published in 322 journals by 1,247 authors from 818 institutions in 67 countries. The Journal of Orthopaedic and Sports Physical Therapy had the highest number of publications, with the USA leading in article count. La Trobe University contributed the most articles, while Rathleff MS and Barton CJ emerged as the most prolific authors. Hip and knee strength and core strength, lower extremity kinematics and biomechanics, females (runners), muscle activation, risk factors, gait retraining, clinical practice guidelines, and rehabilitation were research hotspot keywords.

Conclusion

Current research suggests that there is still significant potential for the development of PFPS research. Key areas of focus include the clinical effectiveness of combined hip and knee strengthening to address PFPS, characterization of lower limb kinematics and biomechanics, gait retraining, risk factors, and clinical practice guidelines. Future research could explore the effectiveness of innovative exercise therapies such as blood flow restricting training, gait retraining, and neuromuscular control training for PFPS improvement. Further investigation into gait retraining for runners, particularly females, and clinical efficacy study of a novel PRP formulation for the treatment of PFPS.

Patellofemoral joint geometry and osteoarthritis features 3-10 years after knee injury compared with uninjured knees

In this cross-sectional study, we compared patellofemoral geometry in individuals with a youth-sport-related intra-articular knee injury to uninjured individuals, and the association between patellofemoral geometry and magnetic resonance imaging (MRI)-defined osteoarthritis (OA) features. In the Youth Prevention of Early OA (PrE-OA) cohort, we assessed 10 patellofemoral geometry measures in individuals 3-10 years following injury compared with uninjured individuals of similar age, sex, and sport, using mixed effects linear regression. We also dichotomized geometry to identify extreme (>1.96 standard deviations) features and assessed likelihood of having extreme values using Poisson regression. Finally, we evaluated the associations between patellofemoral geometry with MRI-defined OA features using restricted cubic spline regression. Mean patellofemoral geometry did not differ substantially between groups. However, compared with uninjured individuals, injured individuals were more likely to have extremely large sulcus angle (prevalence ratio [PR] 3.9 [95% confidence interval, CI: 2.3, 6.6]), and shallow lateral trochlear inclination (PR 4.3 (1.1, 17.9)) and trochlear depth (PR 5.3 (1.6, 17.4)). In both groups, high bisect offset (PR 1.7 [1.3, 2.1]) and sulcus angle (PR 4.0 [2.3, 7.0]) were associated with cartilage lesion, and most geometry measures were associated with at least one structural feature, especially cartilage lesions and osteophytes. We observed no interaction between geometry and injury. Certain patellofemoral geometry features are correlated with higher prevalence of structural lesions compared with injury alone, 3-10 years following knee injury. Hypotheses generated in this study, once further evaluated, could contribute to identifying higher-risk individuals who may benefit from targeted treatment aimed at preventing posttraumatic OA.

Associations between anterior knee pain and 2-year patellofemoral cartilage worsening: The MOST study

OBJECTIVE

Anterior knee pain (AKP) is associated with patellofemoral osteoarthritis (PFOA), but longitudinal studies are lacking. If AKP precedes PFOA, it may create an opportunity to identify and intervene earlier in the disease process. The purpose of this study was to examine the longitudinal relation of AKP to worsening patellofemoral (PF) cartilage over two years.

DESIGN

Participants were recruited from the Multicenter Osteoarthritis Study, a longitudinal study of individuals with or at risk for knee osteoarthritis (OA). Exclusion criteria included bilateral knee replacements, arthritis other than OA, and radiographic PFOA. At baseline, participants completed a knee pain map questionnaire and underwent knee magnetic resonance imaging (MRI). Imaging was repeated at 2-year follow-up. Exposure was presence of frequent AKP. Outcome was worsening cartilage damage in the PF joint defined as increase in MRI Osteoarthritis Knee Score from baseline to 2 years. Log-binomial models were used to calculate risk ratios (RR).

RESULTS

One knee from 1083 participants (age 56.7 ± 6.6 years; body mass index 28.0 ± 4.9 kg/m2) was included. Frequent AKP and frequent isolated AKP were present at baseline in 14.5% and 3.6%, respectively. Frequent AKP was associated with an increased risk (RR: 1.78, 95% confidence interval: 1.21, 2.62) of 2-year worsening cartilage damage in the lateral PF compartment. No association was found between frequent AKP and worsening in the medial PF joint.

CONCLUSION

Frequent AKP at baseline was associated with worsening cartilage damage in the lateral PF joint over 2 years.

The landscape of patellofemoral arthroplasty research: a bibliometric analysis

PURPOSE

Patellofemoral arthroplasty (PFA) was shown to be a potentially effective surgical technique for isolated patellofemoral osteoarthritis but varying reports on PFA-related implant failure and complications have rendered the procedure controversial. This study aimed to identify impactful publications, research interests/efforts, and collaborative networks in the field of PFA research.

METHODS

The study used the Web of Science Core Collection (WOSCC) database, Medline, Springer, BIOSIS Citation Index, and PubMed to retrieve relevant publications on PFA research published between 1950-2022. Statistical tests in R software were used for analysis while VOSviewer, Bibliometrix, and CiteSpace were employed for data visualization.

RESULTS

Two hundred forty-one articles were analyzed with the number of published papers increasing over time. Knee was the most frequent journal and Clinical Orthopaedics and Related Research was the most cited journal. Clinical outcomes, such as prosthesis survival, revision, and complications, were researched most frequently as demonstrated by keyword analysis. The United States was the top contributor to cooperative networks, followed by the United Kingdom while Technical University Munich formed close ties among authors.

CONCLUSION

Publications on PFA research have witnessed a notable surge. They primarily came from a limited number of centers and were characterized by low-level evidence. The majority of studies primarily focused on the clinical outcomes of PFA, while revision of PFA and patient satisfaction have emerged as new research areas.

Exercise-Induced Changes in Femoral Cartilage Thickness in Patients With Patellofemoral Pain

CONTEXT

Rehabilitative exercises alleviate pain in patients with patellofemoral pain (PFP); however, no researchers have analyzed the cartilage response after a bout of those athletic activities in patients with PFP.

OBJECTIVE

To determine if a single session of rehabilitative exercises alters femoral cartilage morphology.

DESIGN

Crossover study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twelve participants with PFP (age = 21.0 ± 2.0 years, height = 1.72 ± 0.1 m, mass = 68.7 ± 12.6 kg) and 12 matched healthy participants (age = 21.3 ± 2.8 years, height = 1.71 ± 0.1 m, mass = 65.9 ± 12.2 kg) were enrolled.

INTERVENTION(S)

Participants completed treadmill running, lower extremity strengthening exercises, and plyometric exercises for 30 minutes each.

MAIN OUTCOME MEASURE(S)

Patient-reported outcomes on the visual analog scale, Anterior Knee Pain Scale (AKPS), Knee injury and Osteoarthritis Outcome Score (KOOS), and Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain and Osteoarthritis were collected. Femoral cartilage ultrasonographic images were obtained at 140° of knee flexion. Ultrasound images were segmented into medial and lateral images using the intercondylar notch. Medial and lateral cartilage cross-sectional area (mm2) and echo intensity (EI), defined as the average grayscale from 0 to 255, were analyzed by ImageJ software. The difference between loading conditions was calculated using repeated-measures analysis of variance. The Spearman correlation was calculated to find the association between the cartilage percentage change (Δ%) and patient-reported outcomes.

RESULTS

Pain increased in the PFP group after all loading conditions (P values < .007). No differences were found in cartilage cross-sectional area or EI alteration between or within groups (P values > .06). The KOOS was negatively associated with the Δ% of the lateral femoral cartilage EI after plyometric loading (ρ = -0.87, P = .001), and the AKPS score was positively correlated with the Δ% of lateral femoral cartilage EI (ρ = 0.57, P = .05).

CONCLUSIONS

Ultrasound imaging did not identify cartilaginous deformation after all loading conditions. However, because lateral cartilaginous EI changes were associated with the AKPS and KOOS score, those questionnaires may be useful for monitoring changes in femoral cartilage health.

Radiographic Biomarkers for Knee Osteoarthritis: A Narrative Review

Conventional radiography remains the most widely available imaging modality in clinical practice in knee osteoarthritis. Recent research has been carried out to develop novel radiographic biomarkers to establish the diagnosis and to monitor the progression of the disease. The growing number of publications on this topic over time highlights the necessity of a renewed review. Herein, we propose a narrative review of a selection of original full-text articles describing human studies on radiographic imaging biomarkers used for the prediction of knee osteoarthritis-related outcomes. To achieve this, a PubMed database search was used. A total of 24 studies were obtained and then classified based on three outcomes: (1) prediction of radiographic knee osteoarthritis incidence, (2) knee osteoarthritis progression and (3) knee arthroplasty risk. Results showed that numerous studies have reported the relevance of joint space narrowing score, Kellgren-Lawrence score and trabecular bone texture features as potential bioimaging markers in the prediction of the three outcomes. Performance results of reviewed prediction models were presented in terms of the area under the receiver operating characteristic curves. However, fair and valid comparisons of the models' performance were not possible due to the lack of a unique definition of each of the three outcomes.

Immediate effects of hip strap and foot orthoses on self-reported measures and lower limb kinematics during functional tasks in individuals with patellofemoral osteoarthritis: protocol for a randomised crossover clinical trial

Background

Elevated patellofemoral joint stress has been associated with patellofemoral osteoarthritis (PFOA). Changes in lower limb kinematics, such as excessive femoral adduction and internal rotation and excessive rearfoot eversion during the stance phase of functional activities, may increase patellofemoral stress. There is a lack of studies that assess the effects of interventions for controlling femur and subtalar joint movements during functional activities on self-reported measures in individuals with PFOA. Thus, the primary aim of the study is to determine the immediate effects of the hip strap and foot orthoses during level-ground walking and the single-leg squat test on self-reported outcomes. The secondary aim is to investigate whether the hip strap and foot orthoses result in the kinematic changes that these devices are purported to cause.

Methods

Twenty-nine individuals with PFOA aged 50 years or older will take part in the study. The main outcome is pain intensity. The secondary outcomes are other self-reported measures (global rating of change, acceptable state of symptoms, ease of performance, and confidence) and lower limb kinematics (peak femoral adduction and internal rotation, and peak rearfoot eversion). These outcomes will be assessed during functional tasks performed under three conditions: (i) control condition, (ii) hip strap intervention, and (iii) foot orthoses intervention. To investigate whether these interventions result in the lower limb kinematic changes that they are purported to cause, three-dimensional kinematics of the femur and rearfoot will be captured during each task. Linear mixed models with two fixed factors will be used to test associations between the interventions (control, hip strap, and foot orthoses) and conditions (level-ground walking and single-leg squat test) as well as interactions between the interventions and conditions.

Discussion

To the best of the authors’ knowledge, this is the first study to evaluate the immediate effects of the hip strap and foot orthoses on self-reported measures and lower limb kinematics during functional tasks in individuals with PFOA. The findings of this study will enable future trials to investigate the effects of these interventions in rehabilitation programmes.

Trial registration

ClinicalTrials.gov NCT04332900. Registered on 3 April 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06676-0.

Magnetic Resonance Imaging-Defined Osteoarthritis Features and Anterior Knee Pain in Individuals With, or at Risk for, Knee Osteoarthritis: A Multicenter Study on Osteoarthritis

OBJECTIVE

The lack of strong association between knee osteoarthritis (OA) structural features and pain continues to perplex researchers and clinicians. Evaluating the patellofemoral joint in addition to the tibiofemoral joint alone has contributed to explaining this structure-pain discordance, hence justifying a more comprehensive evaluation of whole-knee OA and pain. The present study, therefore, was undertaken to evaluate the association between patellofemoral and tibiofemoral OA features with localized anterior knee pain (AKP) using 2 study designs.

METHODS

Using cross-sectional data from the Multicenter Osteoarthritis Study, our first approach was a within-person, knee-matched design in which we identified participants with unilateral AKP. We then assessed magnetic resonance imaging (MRI)-derived OA features (cartilage damage, bone marrow lesions [BMLs], osteophytes, and inflammation) in both knees and evaluated the association of patellofemoral and tibiofemoral OA features to unilateral AKP. In our second approach, MRIs from 1 knee per person were scored, and we evaluated the association of OA features to AKP in participants with AKP and participants with no frequent knee pain.

RESULTS

Using the first approach (n = 71, 66% women, mean ± SD age 69 ± 8 years), lateral patellofemoral osteophytes (odds ratio [OR] 5.0 [95% confidence interval (95% CI) 1.7-14.6]), whole-knee joint effusion-synovitis (OR 4.7 [95% CI 1.3-16.2]), and infrapatellar synovitis (OR 2.8 [95% CI 1.0-7.8]) were associated with AKP. Using the second approach (n = 882, 59% women, mean ± SD age 69 ± 7 years), lateral and medial patellofemoral cartilage damage (prevalence ratio [PR] 2.3 [95% CI 1.3-4.0] and PR 1.9 [95% CI 1.1-3.3], respectively) and lateral patellofemoral BMLs (PR 2.6 [95% CI 1.5-4.7]) were associated with AKP.

CONCLUSION

Patellofemoral but not tibiofemoral joint OA features and inflammation were associated with AKP.

Biomechanical characteristics and muscle function in individuals with patellofemoral osteoarthritis: A systematic review of cross-sectional studies

BACKGROUND

Our objective was to investigate kinematic and kinetic characteristics and changes in muscle function in individuals with patellofemoral osteoarthritis compared to healthy individuals.

METHODS

Searches were performed of the Medline, Embase, Web of Science, The Cochrane Library, LILACS, and SciELO databases until May of 2022 for observational studies comparing individuals with patellofemoral osteoarthritis to a control group. The PRISMA guidelines and recommendations of the Cochrane Collaboration were followed. The GRADE approach was used to analyze and synthesize the level of evidence.

FINDINGS

Fourteen studies were included, involving a total of 594 participants (360 with patellofemoral osteoarthritis and 234 controls). The level of evidence for pelvis, hip adduction and knee abduction angles at 45° of knee flexion during the single-leg squat, and knee flexion angle during the task of walking was very low. Regarding muscle strength, the level of evidence for isometric strength of the hip abductors, extensors and external rotators, and concentric strength of the knee extensors and flexors was very low. It was not possible to synthesize any type of evidence for kinetic, electromyography, or muscle volume variables.

INTERPRETATION

The level of evidence was very low for all synthesized evidence for kinematic and muscle strength variables. However, individuals with patellofemoral osteoarthritis have lower isometric strength of the hip abductor muscles. Further studies with adequate adjustment for confounding factors, such as the non-inclusion of individuals with osteoarthritis in the tibiofemoral compartment concomitant to patellofemoral osteoarthritis, are needed to gain a better understanding of the clinical characteristics of patellofemoral osteoarthritis.

Muscle activation, strength, and volume in people with patellofemoral osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

This systematic review investigated whether people with patellofemoral osteoarthritis (PFOA) have muscle strength, volume, and activation around the hip and knee that is different from asymptomatic controls.

METHODS

Searches were carried out in five electronic databases, with terms related to PFOA, including muscle strength, volume and activation. Only studies with at least one group with symptomatic PFOA and one asymptomatic group were included. The methodological quality of the studies was assessed using the Downs and Black checklist. Certainty of evidence was assessed using the GRADE methodology. Using the random effects model, a meta-analysis was performed when there were at least two studies reporting the same domain.

RESULTS

Eight studies (250 participants) met the inclusion criteria. Subjects with PFOA had weaker hip abduction (SMD -0.96; 95%CI = -1.34 to -0.57), hip external rotation (-0.55;-1.07 to -0.03), hip extension (-0.72;-1.16 to -0.28), and knee extension (-0.97;-1.41 to -0.53) when compared to asymptomatic controls. People with PFOA also presented with smaller volumes of the gluteus medius, gluteus minimus, tensor fascia lata, vastus medialis (VM), vastus lateralis (VL) and rectus femoris when compared to asymptomatic controls. Also, people with PFOA presented with changes in muscle activation for the VL, VM and gluteus maximus (GMax) when compared to asymptomatic controls.

CONCLUSION

People with PFOA present with lower strength and volume of the hip and quadriceps muscles and altered muscle activation of the VM, VL and GMax during ascending and descending stairs when compared to asymptomatic controls. However, the certainty of these findings are very low.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (ID = CRD42020197776).

Higher risk of knee arthroplasty during ten-year follow-up if baseline radiographic osteoarthritis involves the patellofemoral joint: a CHECK Cohort Study

Background

Patellofemoral OA is a strong risk factor for progression to generalized whole knee OA, but it is unknown whether involvement of the patellofemoral joint in early radiographic OA (ROA) is associated with risk of undergoing future knee arthroplasty. This is clinically relevant because patellofemoral OA likely requires a different treatment approach than tibiofemoral OA, and identifying prognostic factors for future arthroplasty might assist clinicians with prioritizing and guiding early interventions that could improve long-term outcomes. Therefore, we evaluated association of baseline patellofemoral or tibiofemoral ROA with undergoing knee arthroplasty over 10 years.

Methods

Using the multicenter Cohort Hip and Cohort Knee (CHECK) study, we acquired three views of radiographs in both knees of individuals aged 45–65 years with complaints of knee symptoms in at least one knee. From baseline radiographs, we categorized each knee as having one of four patterns of ROA: no ROA, isolated patellofemoral ROA, isolated tibiofemoral ROA, or combined ROA. We evaluated the 10-year relative hazard for undergoing going arthroplasty, based on baseline ROA pattern, using Cox proportional hazard models, adjusting for age, sex body mass index, and pain severity.

Result

Our sample (n = 842) included 671 (80%) women and had mean (SD) age 56 (5) years, and BMI 26.3 (4.0) kg/m². Arthroplasties were undertaken in 44/1678 knees. In comparison to having no ROA at baseline, adjusted hazard ratios (aHR) for arthroplasty were highest for combined ROA (aHR 14.2 [95% CI 5.8, 34.6]) and isolated patellofemoral ROA (aHR 12.7 [5.6, 29.0]). Isolated tibiofemoral ROA was not significantly associated with arthroplasty (aHR 2.9 [0.6, 13.6]).

Conclusions

In a sample of middle-aged individuals with complaints in one or both knees, the 10-year relative hazard for undergoing arthroplasty, compared to no ROA, was increased when OA involved the patellofemoral joint, regardless of whether it was isolated to the patellofemoral joint or occurred in combination with tibiofemoral OA. Further research is needed to confirm this association and to clarify the causal mechanism of this relationship. However, our results provide preliminary evidence that identifying patellofemoral ROA may be a clinically useful prognostic indicator in early knee OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05549-6.

Frontal plane biomechanics during single-leg squat and hip strength in patients with isolated patellofemoral osteoarthritis compared to matched controls: A cross-sectional study

The patellofemoral compartment of the knee is the most frequently affected by osteoarthritis. However, there is a lack of biomechanics studies on patellofemoral osteoarthritis (PFOA). This study’s purpose was to compare the frontal plane biomechanics of the trunk and lower limb during the single-leg squat and isometric hip abductor torque in individuals with isolated PFOA and controls. Frontal plane kinematics during the single-leg squat were evaluated using a three-dimensional (3-D) motion analysis system. Isometric hip abductor torque was determined using a handheld dynamometer. Twenty individuals participated in the study (10 with PFOA and 10 controls). No significant differences between groups were found regarding age (mean ± SD, PFOA group = 51.8 ± 6.9 versus control group = 47.8 ± 5.5; mean difference = 4, 95% confidence interval [CI] = -1.9 to 9.9, p = 0.20) or body mass index (PFOA group = 27.6 ± 2.2 versus control group = 25.5 ± 2.5; mean difference = 2.1, 95% confidence interval [CI] = -0.1 to 4.3, p = 0.06). Compared to control, the PFOA group presented greater hip adduction in the descending and ascending phases of the single-leg squat at 45° (mean difference [95% CI] = 6.44° [0.39–12.48°], p = 0.04; mean difference [95% CI] = 5.33° [0.24–10.42°], p = 0.045, respectively) and 60° (mean difference [95% CI] = 8.44° [2.15–14.73°], p = 0.01; mean difference [95% CI] = 7.58° [2.1–13.06°], p = 0.009, respectively) of knee flexion. No significant differences between groups were found for the frontal plane kinematics of the trunk, pelvis or knee (p > 0.05). The PFOA group exhibited lower isometric hip abductor torque (mean difference [95% CI] = -0.34 Nm/kg [-0.67 to -0.01 Nm/kg], p = 0.04). The individuals with PFOA presented greater hip adduction than the control group, which could increase lateral patellofemoral joint stress at 45° and 60° of knee flexion in the descending and ascending phases of the single-leg squat. These individuals also exhibited hip abductor weakness in comparison to healthy controls.

The prevalence, incidence, and progression of radiographic thumb base osteoarthritis in a population-based cohort: the Rotterdam Study

OBJECTIVE

To describe the prevalence, incidence, and progression of radiographic thumb carpometacarpal (CMC-1) and trapezioscaphoid (TS) radiographic osteoarthritis (ROA) in the general Dutch population aged ≥55y.

DESIGN

Data were from the first and second cohort of the Rotterdam Study (1990-2005, 4-12 years follow-up, age 55+). Participants underwent bilateral radiographs at baseline (N = 7792) and follow-up (N = 3804), read for Kellgren-Lawrence (K-L) grade. ROA was defined on the joint level as K-L grade ≥2. The prevalence was assessed at baseline, incidence at follow-up in those free of ROA at baseline, and progression in those with ROA. Differences based on sex and age were evaluated using logistic regression models.

RESULTS

At baseline, 1977 (25.3%) had CMC-1 ROA and 1133 (14.5%) TS ROA. The prevalence was higher in females for CMC-1 (aOR = 1.98 95%CI [1.77-2.21]) and TS ROA (aOR = 2.00 [1.74-2.29]) and increased for every year of age (CMC-1 ROA 1.08 [1.07-1.08]) (TS ROA 1.06 [1.05-1.07]). Most (437/512; 85.4%) incident cases of CMC-1 ROA (2994 at risk) were mild (K-L = 2), whereas most (145/167; 86,8%) incident cases of TS ROA (3311 at risk) were moderate to severe (K-L = 3/4). CMC-1 ROA progression was mostly (88/100; 88.0%) seen in the K-L 2 group at baseline, whereas that was (4/17; 23.5%) for TS ROA.

CONCLUSION

CMC-1 ROA and TS ROA are prevalent in the general Dutch population. While incident CMC-1 ROA was primarily mild, incident TS ROA was more often moderate to severe. CMC-1 ROA was a strong predictor for incident TS ROA.

A semi-automatic framework based upon quantitative analysis of MR-images for classification of femur cartilage into asymptomatic, early OA, and advanced-OA groups

To develop a semi-automatic framework for quantitative analysis of biochemical properties and thickness of femur cartilage using magnetic resonance (MR) images and evaluate its potential for femur cartilage classification into asymptomatic (AS), early osteoarthritis (OA), and advanced OA groups. In this study, knee joint MRI data (fat suppressed-proton density-weighted and multi-echo T2-weighted images) of eight AS-volunteers (data acquired twice) and 34 OA patients including 20 early OA (16 Grade-I and 4 Grade-II), 14 advanced-OA (Grade-III) were acquired at 3.0T MR scanner. Modified Outerbridge classification criteria was performed for the clinical evaluation of data by an experienced radiologist. Cartilage segmentation, T2-mapping, 2D-WearMap generation, and subregion analysis were performed semi-automatically using in-house developed algorithms. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were computed for testing the reproducibility of T2 values. One-way analysis of variance with Tukey-Kramer post hoc test was performed for evaluating the differences among the groups. The performance of individual T2 and thickness, as well as their combination using logistic regression, were evaluated with receiver operating characteristics (ROC) curve analysis. The interscan agreement based on the ICC index was 0.95 and the CV was 2.45 ± 1.33%. T2 mean of values greater than 75th percentile showed sensitivity and specificity of 94.1% and 81.3% (AUC = 0.93, cut-off value = 47.9 ms) in differentiating AS volunteers versus OA group, while sensitivity and specificity of 90.0% and 81.3% (AUC = 0.90, cut-off value = 47.9 ms) in differentiating AS volunteers versus early OA groups, respectively. In the differentiation of early OA versus advanced-OA group, ROC results of combination (T2 and thickness) showed the highest sensitivity and specificity of 85.7%, and 70.0% (AUC = 0.79, cut-off value = 0.39) compared with individual T2 and thickness features, respectively. A computer-aided quantitative evaluation of femur cartilage degeneration showed promising results and can be used to assist clinicians in diagnosing OA.

Meniscal anterior and posterior horn heights are associated with MRI-defined knee structural abnormalities in middle-aged and elderly patients with symptomatic knee osteoarthritis

Background

Meniscal morphological changes are associated with knee OA. However, the correlation of meniscal height and OA-related knee structural abnormalities is still not well understood. The purpose of present study is to investigate whether and how meniscal anterior and posterior horn heights are associated with structural abnormalities in knees with symptomatic OA.

Methods

Our sample consisted of 106 patients (61 female, aged 40–73 years) with symptomatic knee OA. Kellgren-Lawrence system was used for radiographic evaluation. On sagittal sequence, medial meniscal posterior horn height (MPH), lateral meniscal anterior horn height (LAH) and lateral meniscal posterior horn height (LPH) were measured on the middle slice through the medial/lateral compartment. Knee structural abnormalities were assessed using the modified whole-organ magnetic resonance imaging score (WORMS). Associations between meniscal anterior and posterior horn heights and knee structural abnormalities were assessed using linear regression analysis.

Results

Higher MPH was significantly associated with higher WORMS score for medial meniscal anterior horn lesion (P = 0.016) but did not have a statistical association with other WORMS parameters. Increased LAH was statistically correlated with decreased WORMS scores for lateral compartmental cartilage lesions (P = 0.001–0.004) and lateral compartmental bone marrow edema patterns (BMEPs) (P = 0.021–0.027). Moreover, LPH was negatively associated with WORMS scores for lateral compartmental cartilage lesions (P = 0.007–0.041) and lateral compartmental BMEPs (P = 0.022–0.044). Additionally, higher MPH was statistically associated with lower trochlea cartilage WORMS score and higher LAH was significantly correlated with higher WORMS score for trochlea subarticular cysts.

Conclusions

Changes of LAH and LPH were inversely associated with the severity of lateral compartmental cartilage lesions and BMEPs, while higher MPH was only significantly correlated with more severe medial meniscal anterior horn lesions. Besides, MPH and LAH were also significantly associated with patellofemoral structural abnormalities. The present study provided novel information for understanding the role of meniscal morphological changes in knee OA, which would be helpful in identifying and evaluating knees with or at risks for OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05143-w.

Obesity impacts the mechanical response and biochemical composition of patellofemoral cartilage: An in vivo, MRI-based investigation

Obesity is a primary risk factor for osteoarthritis. While previous work has addressed relationships between in vivo cartilage mechanics, composition, and obesity in the tibiofemoral joint, there is limited information on these relationships in the patellofemoral joint. The purpose of this study was to compare the patellofemoral cartilage mechanical response to walking in participants with normal and obese body mass indices (BMIs). Additionally, patellar cartilage T1rho relaxation times were measured before exercise to characterize the biochemical composition of the tissue. Fifteen participants (eight with normal BMI and seven with obese BMI) underwent baseline magnetic resonance imaging (MRI) of their right knee. They then walked on a treadmill for 20 min at a speed normalized to their leg length before a second MRI scan. Subsequently, three-dimensional models of the bones and articular surfaces of the patellofemoral joint were created via manual segmentation of the pre- and post-exercise MR images to compute cartilage thickness and strain. Strain was defined as the change in patellofemoral cartilage thickness normalized to the baseline thickness. Results showed that participants with an obese BMI exhibited significantly increased patellofemoral cartilage strain compared to those with a normal BMI (5.4 ± 4% vs. 1.7 ± 3%, respectively; p = 0.003). Furthermore, patellar cartilage T1rho values were significantly higher in participants with obese versus normal BMIs (95 ms vs. 83 ms, respectively; p = 0.049), indicative of decreased proteoglycan content in those with an obese BMI. In summary, the altered patellofemoral cartilage strain and composition observed in those with an obese BMI may be indicative of cartilage degeneration.

Physical therapy and orthopaedic equipment-induced reduction in the biomechanical risk factors related to knee osteoarthritis: a systematic review and Bayesian network meta-analysis of randomised controlled trials

OBJECTIVE

Are physical therapy or orthopaedic equipment efficacious in reducing the biomechanical risk factors in people with tibiofemoral osteoarthritis (OA)? Is there a better therapeutic intervention than others to improve these outcomes?

DESIGN

Systematic review with network meta-analysis (NMA) of randomised trials.

DATA SOURCES

PubMed, Web of Science, Cochrane Library, Embase and MEDLINE were searched through January 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included randomised controlled trials exploring the benefits of using physical therapy or orthopaedic equipment in reducing the biomechanical risk factors which included knee adduction moment (KAM) and knee adduction angular impulse (KAAI) in individuals with tibiofemoral OA.

DATA EXTRACTION AND SYNTHESIS

Two authors extracted data independently and assessed risk of bias. We conducted an NMA to compare multiple interventions, including both direct and indirect evidences. Heterogeneity was assessed (sensitivity analysis) and quantified (I² statistic). Grading of Recommendations Assessment, Development and Evaluation assessed the certainty of the evidence.

RESULTS

Eighteen randomised controlled trials, including 944 participants, met the inclusion criteria, of which 14 trials could be included in the NMA. Based on the collective probability of being the overall best therapy for reducing the first peak KAM, lateral wedge insoles (LWI) plus knee brace was closely followed by gait retraining, and knee brace only. Although no significant difference was observed among the eight interventions, variable-stiffness shoes and neuromuscular exercise exhibited an increase in the first peak KAM compared with the control condition group. And based on the collective probability of being the overall best therapy for reducing KAAI, gait retraining was followed by LWI only, and lower limb exercise.

CONCLUSION

The results of our study support the use of LWI plus knee brace for reducing the first peak KAM. Gait retraining did not rank highest but it influenced both KAM and KAAI and therefore it was the most recommended therapy for reducing the biomechanical risk factors.

Relation of MRI-Detected Features of Patellofemoral Osteoarthritis to Pain, Performance-Based Function, and Daily Walking: The Multicenter Osteoarthritis Study

OBJECTIVE

The study objective was to determine the relationship of magnetic resonance imaging (MRI)-detected features of patellofemoral joint osteoarthritis to pain and functional outcomes.

METHODS

We sampled 1,099 participants from the 60-month visit of the Multicenter Osteoarthritis Study (mean ± SD age: 66.8 ± 7.5 years; body mass index: 29.6 ± 4.8; 65% female). We determined the prevalence of MRI-detected features of patellofemoral joint osteoarthritis (eg, cartilage damage, bone marrow lesions, and osteophytes) and assessed the relationship between these features and knee pain severity, knee pain on stairs, chair stand time, and walking less than 6,000 steps per day. We evaluated the relationship of MRI features to each outcome using logistic and linear regression, adjusting for potential covariates.

RESULTS

Participants with cartilage damage in 3-4 subregions had the highest mean pain severity (22.0/100; 95% confidence interval [CI]: 17.6-26.4 mm). They also showed higher odds of having at least mild pain on stairs (odds ratio [OR]: 3.3; 95% CI: 1.7-6.5) and of walking less than 6,000 steps per day (OR: 2.3; 95% CI: 1.1-4.4) compared with those without cartilage damage. Participants with bone marrow lesions in 3-4 subregions had higher odds of at least mild pain on stairs than those without (OR: 3.3; 95% CI: 2.2-5.2). Participants with osteophytes in 3-4 subregions also had higher odds of walking less than 6,000 steps/day (OR 2.1, 95% CI: 1.3-3.5, respectively).

CONCLUSION

MRI-detected features of osteoarthritis of the patellofemoral joint are related to pain and functional performance. This knowledge highlights the need to develop treatments for those with patellofemoral joint osteoarthritis to improve pain and maximize function.

Machine learning based texture analysis of patella from X-rays for detecting patellofemoral osteoarthritis

OBJECTIVE

To assess the ability of texture features for detecting radiographic patellofemoral osteoarthritis (PFOA) from knee lateral view radiographs.

DESIGN

We used lateral view knee radiographs from The Multicenter Osteoarthritis Study (MOST) public use datasets (n  = 5507 knees). Patellar region-of-interest (ROI) was automatically detected using landmark detection tool (BoneFinder), and subsequently, these anatomical landmarks were used to extract three different texture ROIs. Hand-crafted features, based on Local Binary Patterns (LBP), were then extracted to describe the patellar texture. First, a machine learning model (Gradient Boosting Machine) was trained to detect radiographic PFOA from the LBP features. Furthermore, we used end-to-end trained deep convolutional neural networks (CNNs) directly on the texture patches for detecting the PFOA. The proposed classification models were eventually compared with more conventional reference models that use clinical assessments and participant characteristics such as age, sex, body mass index (BMI), the total Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and tibiofemoral Kellgren-Lawrence (KL) grade. Atlas-guided visual assessment of PFOA status by expert readers provided in the MOST public use datasets was used as a classification outcome for the models. Performance of prediction models was assessed using the area under the receiver operating characteristic curve (ROC AUC), the area under the precision-recall (PR) curve -average precision (AP)-, and Brier score in the stratified 5-fold cross validation setting.

RESULTS

Of the 5507 knees, 953 (17.3%) had PFOA. AUC and AP for the strongest reference model including age, sex, BMI, WOMAC score, and tibiofemoral KL grade to predict PFOA were 0.817 and 0.487, respectively. Textural ROI classification using CNN significantly improved the prediction performance (ROC AUC = 0.889, AP = 0.714).

CONCLUSION

We present the first study that analyses patellar bone texture for diagnosing PFOA. Our results demonstrates the potential of using texture features of patella to predict PFOA.

Clinical value of weight-bearing CT and radiographs for detecting patellofemoral cartilage visualized by MRI in the MOST study

OBJECTIVE

The patellofemoral joint is frequently affected by osteoarthritis (PFOA) and is incompletely imaged on radiographs (XR). Weight-Bearing CT (WBCT) could offer advantages for visualization. This study determined the sensitivity, specificity, and accuracy of axial WBCT and lateral XR for detection of PFOA features in comparison with cartilage damage on MRI.

DESIGN

A convenience sample of 60 right knees from the MOST cohort were analyzed. WBCT and XR were read for OARSI JSN score and MRI for MOAKS cartilage score by two experienced musculoskeletal radiologists blinded to participant. Using MOAKS scoring on MRI (referent standard), the sensitivity, specificity and accuracy of patellofemoral OARSI JSN scores based on WBCT and XR were compared.

RESULTS

The mean ± SD age and BMI for the participants included (66.7% women) were 67.6 ± 9.8 years and 30.0 ± 5.3 kg/m² respectively. WBCT demonstrated significantly greater sensitivity (0.85-0.97 on WBCT vs 0.47-0.57 on XR) and accuracy (0.85-0.92 on WBCT vs 0.48-0.57 on XR) for all parameters except lateral full-thickness cartilage loss (McNemar's test p-values all <0.001). There was moderate-to-strong and low-to-moderate agreement between PFOA findings on WBCT and XR, respectively, and semi-quantitative scores of PF cartilage on MRI. Inter-rater reliability for XR JSN [weighted kappa = 0.83 (0.64, 1.0)], WBCT JSN [kappa = 0.60 (0.48, 0.72)] and MRI MOAKS-CM [kappa = 0.70 (0.61, 0.79)] readings were good.

CONCLUSION

WBCT demonstrates significantly greater sensitivity and accuracy than radiographs for identification of PFOA. Given the same Relative Radiation Level as XR and improved visualization, WBCT holds promise to improve understanding of the weight-bearing patellofemoral joint.

Automated detection of patellofemoral osteoarthritis from knee lateral view radiographs using deep learning: data from the Multicenter Osteoarthritis Study (MOST)

OBJECTIVE

To assess the ability of imaging-based deep learning to detect radiographic patellofemoral osteoarthritis (PFOA) from knee lateral view radiographs.

DESIGN

Knee lateral view radiographs were extracted from The Multicenter Osteoarthritis Study (MOST) public use datasets (n = 18,436 knees). Patellar region-of-interest (ROI) was first automatically detected, and subsequently, end-to-end deep convolutional neural networks (CNNs) were trained and validated to detect the status of patellofemoral OA. Patellar ROI was detected using deep-learning-based object detection method. Atlas-guided visual assessment of PFOA status by expert readers provided in the MOST public use datasets was used as a classification outcome for the models. Performance of classification models was assessed using the area under the receiver operating characteristic curve (ROC AUC) and the average precision (AP) obtained from the Precision-Recall (PR) curve in the stratified 5-fold cross validation setting.

RESULTS

Of the 18,436 knees, 3,425 (19%) had PFOA. AUC and AP for the reference model including age, sex, body mass index (BMI), the total Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and tibiofemoral Kellgren-Lawrence (KL) grade to detect PFOA were 0.806 and 0.478, respectively. The CNN model that used only image data significantly improved the classifier performance (ROC AUC = 0.958, AP = 0.862).

CONCLUSION

We present the first machine learning based automatic PFOA detection method. Furthermore, our deep learning based model trained on patella region from knee lateral view radiographs performs better at detecting PFOA than models based on patient characteristics and clinical assessments.

The Comprehensive Aachen Knee Score: Development and validation of a new patient-reported outcome measure for patellofemoral pathologies

BACKGROUND

Existing patient-reported outcome measures (PROMs) that assess knee pain and symptoms show insufficient quality regarding their psychometric properties. We developed and validated a new PROM assessing knee pain and especially patellofemoral pathologies, the COMPrehensive AaChen Knee Score (COMPACK).

METHODS

We followed a three-phase process of development and validation. (1) Scale development: we conducted a systematic literature research to collect and analyse the most commonly used PROMs for knee and patellofemoral pathologies to identify appropriate items. (2) Pilot testing: we assessed the content validity of the COMPACK based on interviews with patients and health experts regarding relevance, comprehensibility and comprehensiveness of the used items. (3) Field testing: we used the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines to evaluate the structural validity, internal consistency and test-retest reliability of the COMPACK.

RESULTS

The COMPACK scale showed good structural validity, with two subscales measuring pain intensity and frequency. Further, scores of the COMPACK correlated positively with those obtained from the International Knee Documentation Committee Subjective Knee Form (IKDC) (r = 0.64) and the 12-item Short Form Health Survey subscale of physical function: (r = 0.43). Both the total scale and the two subscales showed good internal consistency (Cronbach's α > 0.82) and good to excellent test-retest reliability (Cronbach's α > 0.82).

CONCLUSIONS

The final COMPACK score was shown to be a valid and reliable instrument and thus meets the most important psychometric quality criteria. In its development, we specifically focused on its content validity, structural validity and applicability.

Association between Patellofemoral and medial Tibiofemoral compartment osteoarthritis progression: exploring the effect of body weight using longitudinal data from osteoarthritis initiative (OAI)

OBJECTIVES

To investigate the associations of medial and lateral patellofemoral osteoarthritis (PF-OA) at baseline with symptomatic and radiographic OA outcomes in the medial tibiofemoral compartment (MTFC) over 4 years, according to baseline overweight status.

METHODS

Data and MRI images of 600 subjects in the FNIH-OA biomarkers consortium were used. Symptomatic worsening and radiographic progression of MTFC-OA were defined using Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain scores and MTFC joint space narrowing (JSN) from baseline to 4-year follow-up. Baseline MRIs were read to establish PF-OA diagnosis. The association between baseline regional PF-OA pattern and odds for MTFC-OA progression was evaluated using regression models (adjusted for relevant confounding covariates including body mass index (BMI), age, sex, PF alignment measurements, KL grade, and knee alignment). To evaluate the effect modifying role for overweight status, stratification analysis was performed (BMI ≥ 25 vs. < 25 kg/m²).

RESULTS

At baseline, 340 (56.7%), 255 (42.5%), and 199 (33.2%) subjects had OA in the medial, lateral, and both PF compartments. Baseline medial PF-OA was associated with WOMAC pain score and MTFC JSN progression at 4 years (Adjusted OR:1.56[95%CI:1.09-2.23] and 1.59[1.11-2.28], respectively) but not lateral PF-OA. In stratification analysis, overweight status was found to be an effect modifier for medial PF-OA and WOMAC pain (OR in overweight vs. non-overweight subjects:1.65[1.13-2.42] vs. 0.50[0.12-1.82]) as well as MTFC-JSN progression (1.63[1.12-2.4] vs. 0.75[0.19-2.81]).

CONCLUSIONS

In addition to the known confounding effect of BMI for PF-OA and MTFC-OA, the overweight status may also play an effect modifier role in the association between baseline medial PF-OA and MTFC-OA progression, which is amenable to secondary prevention.

Incidence and related risk factors of radiographic knee osteoarthritis: a population-based longitudinal study in China

OBJECTIVE

To explore the incidence and risk factors for radiographic knee osteoarthritis (ROA) in a suburban area of China.

METHODS

Shunyi Osteoarthritis Study was a population-based, longitudinal study of knee osteoarthritis in Shunyi, a suburban area of Beijing, China. A total of 1295 residents aged over 50 years were recruited with fully informed by randomized cluster sampling and were followed up 3 years later. At the time of baseline and follow-up visits, participants completed a home interview questionnaire and received a clinical examination including height, weight, range of motion (ROM), chair stand test, 50-foot walk test, and weight-bearing posterior-anterior semi-flexed view of radiographs at tibiofemoral joints. The incident ROA for a knee was defined if its KL grade was no more than grade 1 at baseline visit and no less than grade 2 at the follow-up visit. A patient without ROA in both knees at the baseline visit and with ROA in at least one knee at the follow-up visit was viewed as an incident case of ROA in patient level. Generalized linear model and generalized estimating equation were performed to examine the association between socio-demographic factors, physical function as well as baseline knee joint condition, and incident ROA in patient and knee level.

RESULTS

A total of 1295 residents were recruited at baseline in 2014, and 962 (74.3%) residents were followed in 2017. The annual cumulative incidence of ROA was 3.6% at knee level and 5.7% at patient level. Older age (per year, adjusted odds ratio (OR) = 1.079; 95% confidence interval (CI), 1.042-1.117), overweight (adjusted OR = 2.086; 95% CI, 1.286-3.385), female (adjusted OR = 1.756; 95% CI, 1.074-2.877), less ROM (per degree, adjusted OR = 0.952; 95% CI, 0.923-0.983) and Kellgren and Lawrence (KL) grade 1 at baseline (adjusted OR = 8.527; 95% CI, 5.489-13.246) were risk factors for incident ROA.

CONCLUSION

The incidence of knee ROA in Chinese suburban area was high. Advanced age, female, overweight, less range of motion, and KL grade 1 at baseline were associated with an increased risk of incident ROA.

Impaired muscle capacity of the hip and knee in individuals with isolated patellofemoral osteoarthritis: a cross-sectional study

AIMS

The aims of this study were to compare the capacity of the knee and hip muscles between individuals with and without isolated patellofemoral osteoarthritis (PFOA) and to evaluate the impact of PFOA on pain, stiffness, and physical function.

METHODS

This cross-sectional study evaluated muscle capacity of the hip and knee using an isokinetic dynamometer. The isokinetic variables used in the statistical analysis were peak torque, total work, and average power. Pain, stiffness, and physical function were assessed using questionnaires.

RESULTS

A total of 26 individuals participated in the study (13 with PFOA and 13 controls). The PFOA group exhibited lower peak torque, total work, and average power for knee extension and flexion in the concentric mode (p ⩽ 0.01) as well as lower peak torque and total work for knee extension (p ⩽ 0.005) and lower total work for knee flexion (p = 0.05) in the eccentric mode. The PFOA group exhibited lower peak torque of the extensor, abductor, adductor, and internal rotator muscles of the hip (p ⩽ 0.05), less total work of the abductor and adductor muscles (p ⩽ 0.04), and lower average power of eccentric adduction of the hip (p = 0.01) compared with the healthy controls. Compared with the control group, the PFOA group had a higher level of pain, stiffness, and compromised physical functioning self-reported (p ⩽ 0.005).

CONCLUSION

Participants with PFOA exhibited impairments regarding muscle capacity of the hip and knee, higher level of pain and stiffness as well as compromised physical functioning in comparison with healthy controls.

Increased femoral antetorsion correlates with higher degrees of lateral retropatellar cartilage degeneration, further accentuated in genu valgum

PURPOSE

The role of increased femoral antetorsion (femAT) as a contributor to patellofemoral (PF) osteoarthritis (OA) is unknown. The purpose of this study was to investigate whether increased femAT was associated with advanced cartilage degeneration in the lateral PF joint.

METHODS

Patients who underwent complete radiographic workup for surgical intervention due to OA in any knee joint compartment were included. Cartilage morphology according to the International Cartilage Repair Society (ICRS) cartilage lesion classification system in the PF joint, femoral and tibial torsion, frontal leg axis, and tibial tuberosity-trochlear groove (TT-TG) distance were assessed. Increased femAT was defined as  > 20° according to previous reports.

RESULTS

A total of 144 patients were included. Ninety-seven patients had a femAT of  < 20° and 45 of  > 20°. A significant odds ratio (OR) was found for lateral retropatellar (OR 3.5; p = 0.02) ICRS grade 3 and 4 cartilage degeneration and increased femAT  ≥ 20°. In the medial PF compartment, increased femAT had an inverse effect (OR 0.16; p = 0.01). No significant ORs were found for TT-TG distance, tibial torsion, or leg axis. The lateral retropatellar ICRS grade showed a linear correlation to increased femAT values. In valgus knees, isolated lateral PF OA had an even more pronounced correlation to increased femAT (p = 0.004).

CONCLUSION

Increased femAT showed higher grades of lateral retropatellar cartilage degeneration, which was even more pronounced in valgus knees.

LEVEL OF EVIDENCE

Cohort study: Level III.

The compartmental distribution of knee osteoarthritis - a systematic review and meta-analysis

OBJECTIVES

For a population with knee osteoarthritis (OA), determine: 1) the prevalence of single compartmental, bicompartmental and tricompartmental OA, 2) the prevalence of isolated medial tibiofemoral, lateral tibiofemoral, or patellofemoral OA, and combinations thereof.

METHODS

PubMed and Web of Science databases, and reference lists of identified studies, were searched to find studies which reported on the compartmental distribution and prevalence of knee OA. Two independent reviewers assessed studies against pre-defined inclusion criteria and prevalence data were extracted along with subject characteristics. The methodological quality of each included study was assessed. A random-effects model meta-analysis was performed for each OA category to estimate the relative prevalence of OA in the knee compartments amongst people with knee OA.

RESULTS

16 studies (3,786 knees) met the inclusion criteria. High heterogeneity was measured. Normalised for knees with OA, estimated prevalence rates (95% CI) were: single compartmental 50% (31.5-58.3%), bicompartmental 33% (23.1-37.2%) and tricompartmental only 17% (8.8-24.8%). Isolated medial tibiofemoral OA, isolated patellofemoral OA, and combined medial tibiofemoral and patellofemoral OA were more common than tricompartmental disease, occurring in 27% (15.2-31.1%), 18% (9.9-22.7%) and 23% (14.1-27.3%) of people respectively. Single/bicompartmental patterns of disease involving the lateral tibiofemoral compartment were less common, summing to 15% (8.5-18.7%).

CONCLUSION

Three-quarters of people with knee OA do not have tricompartmental disease. This is not reflected in the frequency with which partial and combined partial knee arthroplasties are currently used.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42019140345).

Kellgren & Lawrence grading in cohort studies: methodological update and implications illustrated using data from the CHECK cohort

Objective

The Cohort Hip and Cohort Knee (CHECK) is a cohort of middle‐aged individuals with hip or knee pain. Radiographs were assigned Kellgren/Lawrence (K/L) scores under different conditions at each follow‐up visit for 10 years. We aimed to describe and consolidate each scoring approach, then illustrate implications of their use by comparing baseline K/L scores assigned using 2 of these approaches, and evaluating their respective associations with joint replacement and incident radiographic osteoarthritis (ROA).

Methods

We compared baseline K/L scores assigned to hips and knees using 2 scoring approaches: 1) assigned by senior researchers to baseline images alone and 2) assigned by trained readers, with images read paired and in known sequence with up to 10 years of follow‐up radiographs (Poisson regression). We evaluated the associations of baseline ROA (any: K/L grade ≥1; established: K/L ≥2) with joint replacement, and of K/L 1 joints with incident established ROA (survival analysis).

Results

Of 1,002 participants (79% women, mean ± SD age 55.9 ± 5.2 years, body mass index 26.2 ± 4.0 kg/m²), the second scoring approach had 2.4 times (95% confidence interval [95% CI] 1.8–3.1 for knees) and 2.9 times (95% CI 2.3–3.7 for hips) higher prevalence of established ROA than the first approach. Established hip ROA had a higher risk of joint replacement using the first approach (hazard ratio [HR] 24.2 [95% CI 15.0–39.8] versus second approach HR 7.7 [95% CI 4.9–12.1]), as did knees (HR 19.3 [95% CI 10.3–36.1] versus second approach HR 4.8 [95% CI 2.4–9.6]). The risk of incident ROA did not differ by approach.

Conclusion

This study demonstrates that evaluating ROA prevalence and predicting outcomes depends on the scoring approach.

Medial femoral condyle fracture during an Oxford unicompartmental knee replacement surgery: case report

Oxford unicompartmental knee arthroplasty has been used as a good alternative for medial unicompartmental osteoarthritis due to its association with early rehabilitation and a low rate of intraoperative complications. This case describes a rare complication during the procedure of an intraoperative fracture of the medial condyle that was treated with osteosynthesis with 6.5 mm cannulated screws and a compression technique. The patient followed a non-weight-bearing protocol for 6 weeks and reached full range of motion at 3 months. Complete radiological fusion and good functional outcome were observed. Intraoperative fractures can benefit from stable osteosynthesis that allows free range of motion and does not jeopardise the final surgical result.

Global, regional prevalence, incidence and risk factors of knee osteoarthritis in population-based studies

BACKGROUND

Knee osteoarthritis (OA) is a major cause of disability in the elderly, however, there are few studies to estimate the global prevalence, incidence, and risk factors of knee OA.

METHODS

For this study, we searched PUBMED, EMBASE and SCOPUS from inception to April 4, 2020, without language restriction. We identified eligible studies with information on the prevalence or incidence of knee OA in population-based observational studies and extracted data from published reports. We did random-effects meta-analysis to generate estimates. This study was registered with PROSPERO (CRD42020181035).

FINDINGS

Out of 9570 records identified, 88 studies with 10,081,952 participants were eligible for this study. The pooled global prevalence of knee OA was 16⋅0% (95% CI, 14⋅3%-17⋅8%) in individuals aged 15 and over and was 22⋅9% (95% CI, 19⋅8%-26⋅1%) in individuals aged 40 and over. Correspondingly, there are around 654⋅1 (95% CI, 565⋅6-745⋅6) million individuals (40 years and older) with knee OA in 2020 worldwide. The pooled global incidence of knee OA was 203 per 10,000 person-years (95% CI, 106-331) in individuals aged 20 and over. Correspondingly, there are around annual 86⋅7 (95% CI, 45⋅3-141⋅3) million individuals (20 years and older) with incident knee OA in 2020 worldwide. The prevalence and incidence varied substantially between individual countries and increased with age. The ratios of prevalence and incidence in females and males were 1⋅69 (95% CI, 1⋅59-1⋅80, p<0⋅00) and 1⋅39 (95% CI, 1⋅24-1⋅56, p<0⋅00), respectively.

INTERPRETATION

Our study provides the global prevalence (16⋅0% [95% CI, 14⋅3%-17⋅8%]) and incidence (203 per 10,000 person-years [95% CI, 106-331]) of knee OA. These findings can be used to better assess the global health burden of knee OA. Further prospective cohort studies are warranted to identify modifiable risk factors for providing effectively preventive strategies in the early stages of the disease.

FUNDING

This work was supported by grants from the National Natural Science Foundation of China (nos. 81772384 and 81572174).

Psychological and Pain Sensitization Characteristics Are Associated With Patellofemoral Osteoarthritis Symptoms: The Multicenter Osteoarthritis Study

OBJECTIVE

Determine the relation of symptomatic and structural features of patellofemoral osteoarthritis (PFOA) to psychological characteristics and measures of pain sensitization, in older adults with or at risk of knee osteoarthritis (OA).

METHODS

This study included 1112 participants from the Multicenter Osteoarthritis Study (713 females, mean age 66.8 ± SD 7.6 yrs, body mass index 29.5 ± 4.8 kg/m²). Participants were grouped based on the presence of PFOA symptoms (anterior knee pain and pain on stairs) and magnetic resonance imaging (MRI) PFOA (full-thickness cartilage lesion with bone marrow lesion): (1) patellofemoral (PF) symptoms with MRI PFOA; (2) PF symptoms without MRI PFOA; (3) MRI PFOA without PF symptoms; and (4) no PF symptoms or MRI PFOA (no PFOA). Relation of PFOA classification to depressive symptoms, catastrophizing, temporal summation (TS) and pressure pain thresholds (PPT) was evaluated using logistic (categorical variables) and linear regression (continuous variables).

RESULTS

Compared with no PFOA, those with PF symptoms with or without MRI PFOA had significantly greater odds of depressive symptoms, catastrophizing, and patellar TS (OR range 1.5-2.01), and those with PF symptoms without MRI PFOA had significantly greater odds of wrist TS (OR 1.66). Males with PF symptoms without MRI PFOA had significantly lower pressure PPT at the patella compared with no PFOA and those with MRI PFOA only (no symptoms). There were no significant differences at the wrist for males, or the patella or wrist for females.

CONCLUSION

Persons with PFOA symptoms, regardless of MRI PFOA status, are more likely to demonstrate depressive symptoms, catastrophizing, and TS. Males with PFOA symptoms without MRI PFOA demonstrate local hyperalgesia.

Associations of foot and ankle characteristics with knee symptoms and function in individuals with patellofemoral osteoarthritis

BACKGROUND

Foot and ankle characteristics are associated with patellofemoral pain (PFP) and may also relate to patellofemoral osteoarthritis (PFOA). A greater understanding of these characteristics and PFOA, could help to identify effective targeted treatments.

OBJECTIVES

To determine whether foot and ankle characteristics are associated with knee symptoms and function in individuals with PFOA.

METHODS

For this cross-sectional study we measured weightbearing ankle dorsiflexion range of motion, foot posture (via the Foot Posture Index [FPI]), and midfoot mobility (via the Foot Measurement Platform), and obtained patient-reported outcomes for knee symptoms and function (100 mm visual analogue scales, Anterior Knee Pain Scale [AKPS], Knee injury and Osteoarthritis Outcome Score, repeated single step-ups and double-leg sit-to-stand to knee pain onset). Pearson's r with significance set at p < 0.05 was used to determine the association between foot and ankle charateristics, with knee symptoms and function, adjusting for age.

RESULTS

188 participants (126 [67%] women, mean [SD] age of 59.9 [7.1] years, BMI 29.3 [5.6] kg/m²) with symptomatic PFOA were included in this study. Lower weightbearing ankle dorsiflexion range of motion had a small significant association with higher average knee pain (partial r = - 0.272, p < 0.001) and maximum knee pain during stair ambulation (partial r = - 0.164, p = 0.028), and lower scores on the AKPS (indicative of greater disability; partial r = 0.151, p = 0.042). Higher FPI scores (indicating a more pronated foot posture) and greater midfoot mobility (foot mobility magnitude) were significantly associated with fewer repeated single step-ups (partial r = - 0.181, p = 0.023 and partial r = - 0.197, p = 0.009, respectively) and double-leg sit-to-stands (partial r = - 0.202, p = 0.022 and partial r = - 0.169, p = 0.045, respectively) to knee pain onset, although the magnitude of these relationships was small. The amount of variance in knee pain and disability explained by the foot and ankle characteristics was small (R²-squared 2 to 8%).

CONCLUSIONS

Lower weightbearing ankle dorsiflexion range of motion, a more pronated foot posture, and greater midfoot mobility demonstrated small associations with worse knee pain and greater disability in individuals with PFOA. Given the small magnitude of these relationships, it is unlikely that interventions aimed solely at addressing foot and ankle mobility will have substantial effects on knee symptoms and function in this population.

TRIAL REGISTRATION

The RCT was prospectively registered on 15 March 2017 with the Australia and New Zealand Clinical Trials Registry ( ANZCTRN12617000385347 ).

Relation of Patellofemoral Joint Alignment, Morphology, and Radiographic Osteoarthritis to Frequent Anterior Knee Pain: Data from the Multicenter Osteoarthritis Study

OBJECTIVE

Patellofemoral (PF) alignment and trochlear morphology are associated with PF osteoarthritis (OA) and knee pain, but whether they are associated with localized anterior knee pain is unknown, which is believed to be a symptom specific to PF joint pathology. We therefore aimed to evaluate the relation of PF alignment and morphology, as well as PFOA and tibiofemoral OA, to anterior knee pain.

METHODS

The Multicenter Osteoarthritis Study is a cohort study of individuals with, or at risk for, knee OA. We evaluated cross-sectional associations of PF alignment, trochlear morphology, and PF and tibiofemoral radiographic OA, with localized anterior knee pain (defined with a pain map). We used 2 approaches: a within-person knee-matched evaluation of participants with unilateral anterior knee pain (conditional logistic regression), and a cohort approach comparing those with anterior knee pain to those without (binomial regression).

RESULTS

With the within-person knee-matched approach (n = 110; 64% women, mean age 70 years, body mass index [BMI] 30.9), PF alignment, morphology, and tibiofemoral OA were not associated with unilateral anterior knee pain. Radiographic PFOA was associated with pain, odds ratio 5.3 (95% confidence interval [95% CI] 1.6-18.3). Using the cohort approach (n = 1,818; 7% of knees with anterior knee pain, 59% women, mean age 68 years, BMI 30.4), results were similar: only PFOA was associated with pain, with a prevalence ratio of 2.2 (95% CI 1.4-3.4).

CONCLUSION

PF alignment and trochlear morphology were not associated with anterior knee pain in individuals with, or at risk for, knee OA. Radiographic PFOA, however, was associated with pain, suggesting that features of OA, more so than mechanical features, may contribute to localized symptoms.

Associations of trochlea morphology and patellofemoral alignment with prevalent radiographic patellofemoral osteoarthritis

OBJECTIVE

To investigate the relation of trochlea morphology and patellofemoral alignment to prevalent radiographic patellofemoral osteoarthritis (PFOA).

DESIGN

A within-person knee-matched case-control study was performed. Participants with unilateral radiographic PFOA were selected from the Multicenter Population-based Osteoarthritis Study (MPOA) in three towns in northern China that was approved by Peking University Health Science Center Ethics Committee (2018PHB166-01). Radiographic PFOA, radiographic tibiofemoral OA, sulcus angle, patellofemoral index and patella displacement were assessed using posterio-anterior and skyline views of the knee. We classified sulcus angle, patellofemoral index and patella displacement into quarters and investigated the relation of each of these measures to prevalent radiographic PFOA.

RESULTS

Among 451 participants (mean age: 65.2 years, women: 66.8%) with unilateral radiographic PFOA, a reverse J-shaped relationship was observed between sulcus angle and prevalent radiographic PFOA (P = 0.039 for quadratic term). Both higher patellofemoral index and patella displacement were associated with higher prevalent radiographic PFOA. Adjusted odds ratios (ORs) of prevalent radiographic PFOA in the highest quarter of patellofemoral index and patella displacement were 4.69 and 3.60 (P for trend <0.001), respectively, compared with the lowest quarter of each measurement. A similar relationship was observed between sulcus angle with either prevalent radiographic lateral or medial PFOA. Higher values of patellofemoral index and patella displacement were statistically significantly associated with higher prevalent radiographic lateral (ORs = 5.07 and 4.59, respectively), but not medial PFOA (ORs = 0.58 and 0.76, respectively).

CONCLUSION

Extreme sulcus angles as well as higher values of patellofemoral index and patella displacement were associated with higher prevalent radiographic PFOA.

High prevalence of patellofemoral osteoarthritis in China: a multi-center population-based osteoarthritis study

BACKGROUND

To describe the prevalence and risk factors of patellofemoral osteoarthritis (PFOA) among Chinese residents.

METHODS

A multi-center population-based osteoarthritis study was conducted in 2014. Residents aged ≥ 50 years old were recruited using a cluster sampling method. Subjects completed a home interview and physical examination and had skyline view of radiographs at patellofemoral (PF) joints. Radiographs were read by two trained musculoskeletal researchers, and discordance of a subject's PFOA status between two readers was adjudicated with a third musculoskeletal researcher present. Radiographic OA at PF joint was defined if osteophytes (OST) score was ≥ 2 or if joint space narrowing (JSN) score was ≥ 2 with concurrent grade 1 OST in the PF joint.

RESULTS

Of 3446 subjects (63.0% women) included in this analysis, the prevalence of radiographic PFOA was 23.9% (20.5% men vs. 25.8% women). Prevalence of lateral radiographic OA was higher than medial radiographic OA at PF joint. Grades of both osteophytes and joint space narrowing in the lateral patellofemoral compartment were higher than those in the medial patellofemoral compartment (all P values < 0.001). Women, older age, higher BMI, and fewer years of education were significantly associated with higher prevalence of radiographic PFOA, osteophytes, and joint space narrowing.

CONCLUSION

Prevalence of radiographic PFOA was high among Chinese population. Key Points • The multi-center population-based osteoarthritis study shows the prevalence of radiographic PFOA was high among Chinese population. • Older age, female gender, obesity, and few years of education were associated with a high risk of PFOA. • Prevalence of lateral radiographic OA was higher than medial radiographic OA at PF joint.

Potential predictive value of axial T2 mapping at 3 Tesla MRI in patients with untreated patellar cartilage defects over a mean follow-up of four years

OBJECTIVE

The objective was to demonstrate the potential of axial T2 mapping for quantification of untreated early-stage patellar cartilage lesions over time and to assess its capability as a potential predictive marker for future progression.

STUDY DESIGN & METHODS

Thirty patients (mean age, 36.7 ± 11.1 years; 16 males), with early-stage patellar cartilage defects (≤ICRS grade 2) at baseline and no treatment during follow up (4.0 ± 1.6 years) were enrolled. Morphological cartilage changes over time were subdivided into a Progression, Non-Progression Group and Regression Group. Quantitative analysis of cartilage defects and healthy reference was performed by means of global and zonal T2 mapping (deep and superficial cartilage T2 values) at both time points. Statistical evaluation included analysis of variance (ANOVA), paired t Test's and ROC analysis.

RESULTS

The Progression Group (N = 11) had significantly higher global T2 values at baseline (57.4 ± 7.8 ms) than patients without (N = 17) (40.6 ± 6.9 ms) (P < 0.01). Furthermore the Non-Progression Group showed only a minor increase in global T2 relaxation times to 43.1 ± 7.9 ms (P = 0.07) at follow up, whereas in the progression group global (68,7 ± 19 ms: P = 0.02) and superficial T2 values (65,8 ± 8.2-79.8 ± 24.4 ms; P = 0.03) increased significantly. T2 values for healthy reference cartilage remained stable. In 2 patients an improvement in ICRS grading was observed (Regression Group) with decreasing T2 values. The ROC analysis showed an area under the curve of 0.92 (95%CI 0.82-1.0). At a cut-off value of 47.15 ms, we found a sensitivity of 92% (false-positive rate of 18%) for future progression of cartilage defects.

CONCLUSIONS

This study provides evidence regarding the possible potential of axial T2 mapping as a tool for quantification and prediction of patellar cartilage defect progression in untreated defects.

Musculoskeletal Pain, Physical Function, and Quality of Life After Bariatric Surgery

OBJECTIVES

To evaluate the longitudinal effects of metabolic and bariatric surgery (MBS) on the prevalence of musculoskeletal and lower extremity (LE) pain, physical function, and health-related quality of life.

METHODS

The Teen Longitudinal Assessment of Bariatric Surgery study (NCT00474318) prospectively collected data on 242 adolescents undergoing MBS at 5 centers over a 3-year follow-up. Joint pain and physical function outcomes were assessed by using the Health Assessment Questionnaire Disability Index, Impact of Weight on Quality of Life - Kids, and the Short Form 36 Health Survey. Adolescents with Blount disease (n = 9) were excluded.

RESULTS

Prevalent musculoskeletal and LE pain were reduced by 40% within 12 months and persisted over 3 years. Adjusted models revealed a 6% lower odds of having musculoskeletal pain (odds ratio = 0.94, 95% confidence interval: 0.92-0.99) and a 10% lower odds of having LE pain (odds ratio = 0.90, 95% confidence interval: 0.86-0.95) per 10% reduction of BMI. The prevalence of poor physical function (Health Assessment Questionnaire Disability Index score >0) declined from 49% to <20% at 6 months (P < .05), Physical comfort and the physical component scores, measured by the Impact of Weight on Quality of Life - Kids and the Short Form 36 Health Survey, improved at 6 months postsurgery and beyond (P < .01). Poor physical function predicted persistent joint pain after MBS.

CONCLUSIONS

Joint pain, impaired physical function, and impaired health-related quality of life significantly improve after MBS. These benefits in patient-reported outcomes support the use of MBS in adolescents with severe obesity and musculoskeletal pain and suggest that MBS in adolescence may reverse and reduce multiple risk factors for future joint disease.

Imaging features in incident radiographic patellofemoral osteoarthritis: the Beijing Shunyi osteoarthritis (BJS) study

Background

The present study aims to describe the imaging features in incident radiographic patellofemoral osteoarthritis (RPFOA) population in a Chinese suburban area.

Methods

The Beijing Shunyi osteoarthritis (BJS) study was a population-based, longitudinal and prospective study. Residents were recruited by randomized cluster sampling in 2014 and were followed 3 years later. Home interviews and clinical examinations were performed; weight-bearing posterior-anterior semi-flexed (45-degree) views of the tibiofemoral (TF) joints and skyline (45-degree) views of the patellofemoral (PF) joints were included. For each batch of study films (n = 100), 20 films from the year 2014 and 20 previously read PF radiographs were fed back to test inter−/intra-reader repeatability. The imaging features of incident RPFOA were analyzed. Narrative statistics, independent-sample t-tests, and nonparametric tests were performed.

Results

A total of 1295 participants (2590 knees) were recruited at baseline in 2014, and 967 (74.7%) residents were followed in 2017. Of all the knees (n = 1537) without RPFOA at baseline, 139 knees (13.3%) across 119 people developed incident RPFOA. Compared with the whole population, age (p = 0.031), body mass index (BMI, p = 0.042), and incidence of knee pain symptoms (p < 0.01) were significantly different in the incident RPFOA population, while range of motion (ROM, p = 0.052) and gender (0/1, p = 0.203) showed no significance. In the incident population, the changes of each imaging indicator grade were evaluated—lateral patellofemoral osteophyte (LPOST, increased by 1.02), medial patellofemoral osteophyte (MPOST, increased by 0.49), lateral joint space narrowing (LJSN, increased by 0.30), medial joint space narrowing (MJSN, increased by 0.06); indicator grade progress decreases, respectively. The progress of LPOST was the fastest among the four indicators (p < 0.01).

Conclusions

In this population-based longitudinal study, among the incident RPFOA population, the imaging indicators show that marginal patellofemoral osteophyte is more pronounced than patellofemoral joint space narrowing. LPOST is the fastest-progressing indicator among all the radiographic features, which is also the most common imaging manifestation of RPFOA. In the incident RPFOA population, the proportion of elders, women, higher-BMI individuals, and people suffering knee pain is more than the normal population.

The efficacy of foot orthoses in individuals with patellofemoral osteoarthritis: a randomised feasibility trial

Background

Foot orthoses have the potential to be an efficacious treatment for patellofemoral osteoarthritis (PFOA) but have not been evaluated in clinical trials in this population. This study aimed to determine the: (i) feasibility of conducting a randomised controlled trial (RCT) investigating the efficacy of foot orthoses in individuals with PFOA; and (ii) effects of foot orthoses versus flat shoe inserts on pain, function, and knee-related quality of life (QOL).

Methods

This 6-week, single-blinded pilot RCT randomly allocated participants with PFOA to receive foot orthoses or flat inserts. The primary outcome of feasibility was determined via the following parameters: one participant recruited per week, 20% (35 h/week) adherence to the intervention, 50% log book completion rate, and < 20% drop-out, with results reported using descriptive statistics. Secondary outcomes included average and maximum pain severity (100 mm visual analogue scale), Anterior Knee Pain Scale, and Knee injury and Osteoarthritis Outcome Score, analysed using analysis of covariance.

Results

Twenty-six participants (16 women; mean (SD) age of 60 (8) years) with PFOA were recruited. All feasibility parameters were exceeded, with three participants recruited per week, > 20% (37.2 [9.8] hours/week) adherence to the intervention, 69.2% (18/26) log-book completion, and 3.8% (1/26) drop-outs. The most common adverse events were arch irritation and shoe fit issues, which were more common in the foot orthoses group (67.9% versus 32.1%). There was a trend for the foot orthoses group to report larger improvements in average and maximum pain than the flat insert group, with the mean difference for maximum knee pain severity (21.9 mm, 95% CI − 2.1 to 46.0) exceeding the minimal clinically important difference (15 mm). The estimated sample size for a full-scale RCT is 160 participants. Suggestions to improve study design include a greater number of face-to-face follow-up appointments, a larger variety of foot orthoses to reduce rates of adverse events, and increasing follow-up time to determine long-term efficacy.

Conclusion

This study supports the feasibility of a full-scale RCT to determine the efficacy of foot orthoses versus flat inserts in individuals with PFOA.

Trial registration

The trial protocol was retrospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR number: 12616001287426).

Pressure pain thresholds in adults with patellofemoral pain and patellofemoral joint osteoarthritis: a case-control study

Background and aims

Patellofemoral pain (PFP) and patellofemoral joint osteoarthritis (PFJOA) are common non-self-limiting conditions causing significant pain and disability. The underlying pain pathologies lack consensus with evidence suggesting reduced pressure pain thresholds (PPTs) in adolescent females with PFP and individuals with knee osteoarthritis. A paucity of evidence exists for mixed-sex adults with PFP and PFJOA in isolation. Exploring if pain sensitisation is a dominant feature of PFP and PFJOA may have important implications for the delivery of a patient centred management approach. The primary aim was to measure local and remote PPTs in PFP and PFJOA patients compared to matched controls. Secondary aims were to evaluate the relationship between PPTs and (1) condition severity and (2) knee function.

Methods

13 PFP patients plus 20 matched controls and 15 PFJOA patients plus 34 matched controls were recruited from a UK mixed-sex adult population. Controls were matched on age, sex and activity level. Demographic details, Tegner activity level score, symptom duration, condition severity (Kujala and KOOS-PF scores for PFP and PFJOA, respectively) and knee function (Modified Whatman score rating of five single leg squats) were recorded. PPTs were measured at six sites: five local around the knee, one remote on the contralateral leg. Between-group differences were tested using a two-way mixed model analysis of variance with repeated measures. Strength of association between PPTs and condition severity and knee function were tested using Spearman’s rank order correlation.

Results

No statistically significant difference in PPTs were observed between the PFP patients [F(1,31) = 0.687, p = 0.413, η2 = 0.022] or PFJOA patients [F(1,47) = 0.237, p = 0.629, η2 = 0.005] and controls. Furthermore, no correlation was found between PPTs and condition severity or knee function in PFP or PFJOA (p > 0.05).

Conclusions

Results suggest mechanical pain sensitisation is not a dominant feature of UK mixed-sex adults with PFP or PFJOA.

Implications

PFP and PFJOA remain persistent pain complaints which may not be well explained by objective measures of sensitivity such as PPTs. The findings suggest that peripheral pain processing changes leading to pain sensitisation is not a key feature in PFP or PFJOA. Instead the underlying pain pathway is likely to remain primary nociceptive, possibly with a subgroup of patients who experience pain sensitisation and might benefit from a more targeted management approach.

Neuromotor control during stair ambulation in individuals with patellofemoral osteoarthritis compared to asymptomatic controls

BACKGROUND

Patellofemoral OA is characterized by PF pain during activities that load a flexed knee. Stair stepping ability is frequently impaired, yet little is known of the muscular recruitment strategies utilized during this task. Altered recruitment strategies may provide targets for clinical interventions. We aimed to determine if people with PFOA ascend and descend stairs with different muscular recruitment strategies compared to similar aged healthy individuals.

METHODS

Twenty-two people with PFOA and 20 controls were recruited. Electromyographic recordings from gluteus maximus and medius, medial and lateral hamstrings, vastus medialis and lateralis, medial and lateral gastrocnemius and soleus were acquired during stair ascent and descent. Force plate data was acquired to determine timing of foot placements and characterize dynamic stability.

RESULTS

Seventeen people with PFOA (59 ± 10 years, 73 ± 13 kg, 167 ± 9 cm) and 15 controls (57 ± 10 years, 73 ± 16 kg, 171 ± 11 cm) had complete data. People with PFOA demonstrated: longer vastii activation duration during descent (lateralis: p = 0.01; medialis: p = 0.02); earlier onset of vastus lateralis for ascent (p < 0.01) and descent (p = 0.04); earlier onset of soleus in descent (p = 0.04); and shorter duration of GMax during ascent (p = 0.05). Peak Fz timing (time between the start of the anticipatory postural adjustment and the end of the stepping task) was ∼70ms later during stair descent in PFOA compared to controls (p = 0.01).

SIGNIFICANCE

People with PFOA utilize muscular activation strategies consistent with minimizing knee pain during stair ambulation. Clinical interventions aimed at gluteal and quadriceps activation may be warranted in PFOA.

The FOOTPATH study: protocol for a multicentre, participant- and assessor-blind, parallel group randomised clinical trial of foot orthoses for patellofemoral osteoarthritis

INTRODUCTION

Patellofemoral (PF) osteoarthritis (OA) is a common and burdensome subgroup of knee OA, with very little evidence for effective treatments. Prefabricated foot orthoses are an affordable and accessible intervention that have been shown to reduce PF pain in younger adults. Similarities between PF pain and PFOA, as well as our pilot work, suggest that foot orthoses may also be an effective intervention for PFOA. The primary objective of this study is to compare the 3 month efficacy of prefabricated foot orthoses and flat shoe inserts in people with PFOA, on knee pain severity.

METHODS AND ANALYSIS

The FOOTPATH Study (FOot OrThoses for PAtellofemoral osteoarTHritis) is a multicentre, randomised, participant- and assessor-blinded superiority trial with two parallel groups, a 3 month observation period (pre-randomisation) and 12 month follow-up. 160 participants with a clinical diagnosis of PFOA will be recruited from three sites in Australia, and randomised to one of two groups (prefabricated foot orthoses or flat shoe inserts). The primary outcome is worst knee pain severity during a self-nominated aggravating activity in the previous week (100 mm visual analogue scale) at 3 months, with a secondary endpoint at 12 months. Secondary outcomes include global rating of change, symptoms, function, health-related quality of life, kinesiophobia, self-efficacy and use of co-interventions for knee pain. Blinded, intention-to-treat analyses of primary and secondary patient-reported outcomes will be performed, as well as economic analyses.

ETHICS AND DISSEMINATION

Ethical approval has been granted by La Trobe University's Human Ethics Committee and The University of Queensland's Medical Research Ethics Committee. Study outcomes will be disseminated via peer-reviewed journals, conference presentations targeting a range of healthcare disciplines and an open access website with clinician resources.

TRIAL REGISTRATION NUMBER

ANZCTRN12617000385347; Pre-results.

Proprioceptive Training and Outcomes of Patients With Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To describe the effects of proprioceptive training on pain, stiffness, function, and functional test outcomes among patients with knee osteoarthritis (OA).

DATA SOURCES

All studies completed from 1946 to 2017 were obtained from 4 databases (PubMed, MEDLINE, CINAHL, and SPORTDiscus).

STUDY SELECTION

Three reviewers independently identified appropriate studies and extracted data.

DATA EXTRACTION

Methodologic quality and level of evidence were assessed using the Physiotherapy Evidence Database scale and Oxford Centre for Evidence-Based Medicine guidelines. The standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated for pain, stiffness, function, and functional test outcomes.

DATA SYNTHESIS

Seven randomized controlled trials involving 558 patients with knee OA met the inclusion criteria. The selected studies had Physiotherapy Evidence Database scores of 6 to 8. All randomized controlled trials had an Oxford Centre for Evidence-Based Medicine level of evidence of 2. Meta-analysis of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale (SMD = -0.56; 95% CI = -1.06, -0.07; P = .026), function subscale (SMD = -0.40; 95% CI = -0.59, -0.21; P < .001), and non-WOMAC walking speed test (SMD = -1.07; 95% CI = -2.12, -0.01; P = .048) revealed that proprioceptive training had significant treatment effects. Proprioceptive training was not associated with reductions in WOMAC stiffness subscale scores and did not improve non-WOMAC get-up-and-go scores.

CONCLUSIONS

Proprioceptive training effectively promoted pain relief and completion of functional daily activity among patients with knee OA and should be included in rehabilitation programs. Stiffness and other mobility measures were unchanged after proprioceptive training. Modified proprioceptive training programs are needed to target stiffness and improve additional physical function domains.

Alignment differs between patellofemoral osteoarthritis cases and matched controls: An upright 3D MRI study

Patellofemoral (PF) osteoarthritis (OA) is a prevalent and clinically important knee OA subgroup. Malalignment may be an important risk factor for PF OA. However, little is known about alignment in PF OA, particularly in an upright, weightbearing environment. Using a vertically-oriented open-bore MR scanner, we evaluated 3D knee alignment in 15 PF OA cases and 15 individually matched asymptomatic controls. We imaged one knee per participant while they stood two-legged at four flexion angles (0°, 15°, 30°, 45°), and also while they stood one-legged at 30° knee flexion. We calculated 3D patellofemoral and tibiofemoral alignment. Using mixed effects models, four of the five patellofemoral measures differed by group. For key measures, PF OA patellae were 6.6° [95%CI 5.0, 8.2] more laterally tilted, 2.4 mm [1.3, 3.5] more laterally translated, and at least 3.7 mm [0.2, 7.2] more proximally translated compared to controls (more with knees flexed). Alignment did not differ between two-legged stance and one-legged stance in either group. Statement of Clinical Significance: Our study demonstrated significant and clinically relevant differences in alignment between PF OA cases and controls in upright standing and squatting positions. Our findings were similar to those in previous studies of PF OA using traditional MR scanners in supine positions, supporting the clinical usefulness of existing methods aimed at identifying individuals who may benefit from interventions designed to correct malalignment. © 2019 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. 9999:1-9, 2019.