Rate of cartilage loss at two years predicts subsequent total knee arthroplasty: a prospective study

Knee-Loading Predictions with Neural Networks Improve Finite Element Modeling Classifications of Knee Osteoarthritis: Data from the Osteoarthritis Initiative

Physics-based modeling methods have the potential to investigate the mechanical factors associated with knee osteoarthritis (OA) and predict the future radiographic condition of the joint. However, it remains unclear what level of detail is optimal in these methods to achieve accurate prediction results in cohort studies. In this work, we extended a template-based finite element (FE) method to include the lateral and medial compartments of the tibiofemoral joint and simulated the mechanical responses of 97 knees under three conditions of gait loading. Furthermore, the effects of variations in cartilage thickness and failure equation on predicted cartilage degeneration were investigated. Our results showed that using neural network-based estimations of peak knee loading provided classification performances of 0.70 (AUC, p < 0.05) in distinguishing between knees that developed severe OA or mild OA and knees that did not develop OA eight years after a healthy radiographic baseline. However, FE models incorporating subject-specific femoral and tibial cartilage thickness did not improve this classification performance, suggesting there exists an optimal point between personalized loading and geometry for discrimination purposes. In summary, we proposed a modeling framework that streamlines the rapid generation of individualized knee models achieving promising classification performance while avoiding motion capture and cartilage image segmentation.

Magnetic Resonance Imaging Features and Functional Score in Patients Requiring Total Knee Arthroplasty

Introduction Knee osteoarthritis (KOA) is a progressive degenerative disease, with an increasing prevalence among the population. The degenerative changes in KOA affect the cartilage, menisci, synovial tissue, and subchondral bone. The treatment for patients in advanced stages of the disease is total knee arthroplasty (TKA). The purpose of this descriptive study is to identify the MRI features in the case of patients with KOA who did not obtain an improvement in symptoms and joint function after the non-surgical treatments and who applied for surgical treatment, i.e. TKA. Also, we aimed to identify the correlations between the MRI changes and the functional score of the patients, as well as the inter-variable correlations. Materials and methods The study was conducted in the Department of Orthopedics and Traumatology at the University Emergency Hospital of Bucharest between January 1, 2023, and January 31, 2024. It included 50 patients who required TKA. This study is a prospective, observational, and descriptive analysis focusing on patients scheduled for TKA. Results The patients in the study group who required TKA had a Knee Society Score (KSS) ranging from 35 to 70 and a KSS function score between 24 and 60. Among them, 98% had tricompartmental lesions of the articular cartilage, and 100% presented with osteophytes, even when they were not identifiable radiologically. Additionally, 58% of the patients had changes in the infrapatellar fat pad, 66% presented with joint effusion without any traumatic history, and 86% of the patients had partial or complete lesions of the anterior cruciate ligament. Conclusion The MRI pattern of the patient who requires TKA consists of the presence of articular cartilage lesions in more than two compartments with exposure of the subchondral bone and diameter greater than 1 cm, meniscus lesions (>grade 2), meniscus extrusion (>grade 1), the presence of bone marrow lesions (BMLs) in the medial or lateral compartment of the femur or tibia, hyperintense signal of the infrapatellar fat pad, anterior cruciate ligament (ACL) lesions (>grade 2), and the presence of osteophytes together with the presence of effusion in the suprapatellar bursa. BMLs and changes in the infrapatellar fat pad may lead to the opening of new research perspectives explaining the complex changes in KOA in relation to the inflammatory process and gene expression.

Early cartilage lesion and 5-year incident joint surgery in knee osteoarthritis patients: a retrospective cohort study

OBJECTIVE

to investigate the association between cartilage lesion-related features observed in knee osteoarthritis (OA) patients' first MRI examination and incident knee surgery within 5 years. Additionally, to assess the predictive value of these features for the incident knee surgery.

METHODS

We identified patients diagnosed with knee OA and treated at our institution between January 2015 and January 2018, and retrieved their baseline clinical data and first MRI examination films from the information system. Next, we proceeded to determine joint space narrowing grade, cartilage lesion size grade, cartilage full-thickness loss grade and cartilage lesion sum score for the medial and lateral compartments, respectively. Generalized linear regression models examined the association of these features with 5-year incident knee surgery. Positive and negative predictive values (PPVs and NPVs) were determined referring to 5-year incident knee surgery.

RESULTS

Totally, 878 participants (knees) were found eligible to form the study population. Within the 5 years, surgery was performed on 61 knees. None of the cartilage-related features had been found significantly associated with incident surgery. The results were similar for medial and lateral compartments. The PPVs were low for all the features.

CONCLUSIONS

Among symptomatic clinically diagnosed OA knees, cartilage lesions observed in the first MRI examinations were not found to be associated with the occurrence of joint surgery within a 5-year period. All these cartilage-related features appear to have no additional value in predicting 5-year incident joint surgery.

Role of Serum Micro-RNA-122-5p Expression as a Circulatory Biomarker in People Having Both Knee Osteoarthritis and Osteoporosis: A Case-Control Study

Background Although knee osteoarthritis (KOA) and osteoporosis (OP) manifest distinct pathophysiologies, they share numerous similarities. These health conditions are commonly found in older individuals, particularly among women. The objective of this study is to explore the expression of micro-RNA (miRNA) 122-5p (miR-122-5p) in people affected by both KOA and OP. The main aim is to identify diagnostic biomarkers and potential therapeutic targets, which could help develop personalized treatment approaches. Methods As part of the study, a total of 268 serum samples were collected from the participants, who were divided into four groups: KOA, OP, KOA and OP, and controls, with 67 subjects per group. The miRNA species-containing total RNA was isolated from the serum samples using an miRNeasy serum/plasma kit by QIAGEN (Hilden, Germany). The expression of miR-122-5p was examined in each group using real-time quantitative polymerase chain reaction. Results Expression of miR-122-5p in all three groups (KOA, OP, and common group of KOA and OP) was significantly upregulated, and the fold change value was much higher in the group having both diseases. Conclusions These results might contribute to the identification of cases at risk, early diagnosis, and development, and might also contribute to the development of therapeutic targets in subjects having both KOA and OP.

Association between knee magnetic resonance imaging markers and knee symptoms over 6-9 years in young adults

OBJECTIVES

To describe associations between MRI markers with knee symptoms in young adults.

METHODS

Knee symptoms were assessed using the WOMAC scale during the Childhood Determinants of Adult Health Knee Cartilage study (CDAH-knee; 2008-2010) and at the 6- to 9-year follow-up (CDAH-3; 2014-2019). Knee MRI scans obtained at baseline were assessed for morphological markers (cartilage volume, cartilage thickness, subchondral bone area) and structural abnormalities [cartilage defects and bone marrow lesions (BMLs)]. Univariable and multivariable (age, sex, BMI adjusted) zero-inflated Poisson (ZIP) regression models were used for analysis.

RESULTS

The participants' mean age in CDAH-knee and CDAH-3 were 34.95 (s.d. 2.72) and 43.27 (s.d. 3.28) years, with 49% and 48% females, respectively. Cross-sectionally, there was a weak but significant negative association between medial femorotibial compartment (MFTC) [ratio of the mean (RoM) 0.99971084 (95% CI 0.9995525, 0.99986921), P < 0.001], lateral femorotibial compartment (LFTC) [RoM 0.99982602 (95% CI 0.99969915, 0.9999529), P = 0.007] and patellar cartilage volume [RoM 0.99981722 (95% CI 0.99965326, 0.9999811), P = 0.029] with knee symptoms. Similarly, there was a negative association between patellar cartilage volume [RoM 0.99975523 (95% CI 0.99961427, 0.99989621), P = 0.014], MFTC cartilage thickness [RoM 0.72090775 (95% CI 0.59481806, 0.87372596), P = 0.001] and knee symptoms assessed after 6-9 years. The total bone area was negatively associated with knee symptoms at baseline [RoM 0.9210485 (95% CI 0.8939677, 0.9489496), P < 0.001] and 6-9 years [RoM 0.9588811 (95% CI 0.9313379, 0.9872388), P = 0.005]. The cartilage defects and BMLs were associated with greater knee symptoms at baseline and 6-9 years.

CONCLUSION

BMLs and cartilage defects were positively associated with knee symptoms, whereas cartilage volume and thickness at MFTC and total bone area were weakly and negatively associated with knee symptoms. These results suggest that the quantitative and semiquantitative MRI markers can be explored as a marker of clinical progression of OA in young adults.

Biomarkers in osteoarthritis: current status and outlook - the FNIH Biomarkers Consortium PROGRESS OA study

Currently, no disease-modifying therapies are approved for osteoarthritis (OA) use. One obstacle to trial success in this field has been our existing endpoints' limited validity and responsiveness. To overcome this impasse, the Foundation for the NIH OA Biomarkers Consortium is focused on investigating biomarkers for a prognostic context of use for subsequent qualification through regulatory agencies. This narrative review describes this activity and the work underway, focusing on the PROGRESS OA study.

Association of smoking with cartilage loss of knee osteoarthritis: data from two longitudinal cohorts

BACKGROUND

Previous studies have been inconsistent concerning the association between smoking and risk of osteoarthritis (OA). This study aimed to explore the associations of smoking status and change in cartilage volume of OA in two longitudinal cohorts.

METHODS

Subjects from the Osteoarthritis Initiative cohort (OAI, n = 593) and the Tasmanian Older Adult Cohort (TASOAC, n = 394) were included in this study. For both cohorts, participants were classified into three groups based on their smoking status, namely 'never', 'former', and 'current' smokers. The outcome measures were the annual rate of change of tibiofemoral cartilage volume over 2 years in OAI and of tibial cartilage volume over 2.6 years in TASOAC. Potential confounders were balanced using the inverse probability of treatment weighting (IPTW) method.

RESULTS

Overall, 42.3% and 37.4% of participants were former smokers, and 5.7% and 9.3% were current smokers in the OAI and TASOAC cohorts, respectively. Compared to never smokers, neither former nor current smoking was associated with risk of the annual rate of change of tibiofemoral cartilage volume in OAI (former smoker: β=-0.068%/year, 95% confidence interval [CI] -0.824 to 0.688, p = 0.860; current smoker: β=-0.222%/year, 95% CI -0.565 to 0.120, p = 0.204) and tibial cartilage volume in TASOAC (former smoker: β = 0.001%/year, 95% CI -0.986 to 0.989, p = 0.998; current smoker: β=-0.839%/year, 95% CI -2.520 to 0.844, p = 0.329).

CONCLUSIONS

Our findings from two independent cohorts consistently showed that smoking was not associated with knee cartilage loss in older adults.

Radiofrequency Chondroplasty of the Knee Yields Excellent Clinical Outcomes and Minimal Complications: A Systematic Review

Purpose

To evaluate reported clinical outcomes and complications following radiofrequency (RF) ablation for the treatment of knee chondral lesions.

Methods

A literature search was performed according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines by querying EMBASE, PubMed, and Scopus computerized databases from database inception through October 2022. Level I to IV clinical studies that reported outcomes or complications following RF-based chondroplasty were included. Postoperative outcome scores and complications were aggregated. Study quality was assessed via the Newcastle-Ottawa Scale.

Results

Ten articles from 2002 to 2018 consisting of 1,107 patients (n = 1,504 lesions) were identified. Four studies were of Level I evidence, 3 studies were Level II, 1 study was Level III, and 2 studies were Level IV. The mean patient age was 41.8 ± 6.3 years (range, 12-87). Seven studies (n = 1,037 patients) used bipolar RF devices, and 3 studies (n = 70 patients) used monopolar RF devices. The overall mean postoperative Lysholm, Tegner, and IKDC scores ranged from 83 to 91, 3.8 to 7, and 49 to 90, respectively, in lesions ranging from grade I-IV according to the Outerbridge Classification. Monopolar RF devices reported qualitatively similar mean changes in Lysholm scores (83), Tegner scores (3.8), and IKDC scores (range, 49-69) compared with bipolar RF devices (range, 86.4-91, 4.5-7, 90, respectively). The incidence of complications ranged from 0% to 4%. The most commonly reported complication was osteonecrosis (range, 0% to 4%). The incidence rate of patients undergoing additional surgery ranged from 0% to 4.5%.

Conclusions

The available literature on RF-based chondroplasty shows its efficacy and safety for the treatment of knee chondral lesions, with good clinical outcome scores and low complication and reoperation rates.

Level of Evidence

Level IV, systematic review of Level I-IV studies.

Evaluation of the Outcome of Osteoarthritis among Patients Undergoing Total Knee Replacement

Background

To assess the outcome of osteoarthritis among patients undergoing total knee replacement (TKR).

Materials and Methods

One hundred and four subjects with one hundred and fifty-two cemented total knee arthroplasties have been analyzed in the current research. Functional assessment was carried out using the preoperative and postoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) score and its five subscales: pain, other symptoms, function in activity of daily living (ADL), function in sport and recreation (Sport/Rec), and knee-related quality of life (QOL).

Results

A significant improvement in the KOOS symptom score was seen with score grade changing to excellent from poor. The average postoperative KOOS symptom score occurred to be 89.9198, whereas the mean preoperative KOOS score was 30.7960 with a mean difference of 59.02385. The mean postoperative KOOS pain score was 94.6304 and the mean preoperative KOOS score was 18.4831 with a mean difference of 76.14731. A significant improvement in the KOOS pain score was seen with score grade changing to excellent from poor. Sixty patients of 104 (57.7%) had an excellent satisfaction level with a postoperative range of motion, twenty-eight patients (26.9%) had a good, eleven patients (10.6%) had a fair, and five patients (4.8%) had a poor satisfaction level with a postoperative range of motion.

Conclusion

Surgery for a TKR is successful in reducing individuals' pain and restoring their functional ability. Preoperative expectations and KOOS subscale scores are factors in patients' satisfaction, which is determined a year following surgery.

Intra-Articular Mesenchymal Stem Cell Injection for Knee Osteoarthritis: Mechanisms and Clinical Evidence

Knee osteoarthritis presents higher incidences than other joints, with increased prevalence during aging. It is a progressive process and may eventually lead to disability. Mesenchymal stem cells (MSCs) are expected to repair damaged issues due to trilineage potential, trophic effects, and immunomodulatory properties of MSCs. Intra-articular MSC injection was reported to treat knee osteoarthritis in many studies. This review focuses on several issues of intra-articular MSC injection for knee osteoarthritis, including doses of MSCs applied for injection and the possibility of cartilage regeneration following MSC injection. Intra-articular MSC injection induced hyaline-like cartilage regeneration, which could be seen by arthroscopy in several studies. Additionally, anatomical, biomechanical, and biochemical changes during aging and other causes participate in the development of knee osteoarthritis. Conversely, appropriate intervention based on these anatomical, biomechanical, biochemical, and functional properties and their interactions may postpone the progress of knee OA and facilitate cartilage repair induced by MSC injection. Hence, post-injection rehabilitation programs and related mechanisms are discussed.

Intra-articular injections of platelet-rich plasma decrease pain and improve functional outcomes than sham saline in patients with knee osteoarthritis

PURPOSE

To compare the long-term clinical efficacy provided by intra-articular injections of either Pure Platelet-rich Plasma (P-PRP) or sham saline to treat knee osteoarthritis (KOA).

METHODS

This prospective, parallel-group, double-blind, multi-center, sham-controlled randomized clinical trial recruited participants with KOA from orthopedic departments at nine public hospitals (five tertiary medical centers, four secondary medical units) starting January 1, 2014, with follow-up completed on February 28, 2021. Participants were randomly allocated to interventions in a 1:1 ratio. Data were analyzed from March 1, 2021, to July 15, 2021. Three sessions (1 every week) of P-PRP or sham saline injected by physicians. The primary outcome was the Western Ontario and McMaster Universities Arthritis Index (WOMAC) at 3, 6, 12, 24, 60 months of follow-up. Secondary outcomes included the International Knee Documentation Committee (IKDC) subjective score, visual analogue scale (VAS) score, intra-articular biochemical marker concentrations, cartilage volume, and adverse events. Laboratory of each hospital analyzed the content and quality of P-PRP.

RESULTS

610 participants (59% women) with KOA who received three sessions of P-PRP (n = 308, mean age 53.91 years) or sham saline (n = 302, mean age 54.51 years) injections completed the trial. The mean platelet concentration in PRP is 4.3-fold (95% confidence interval 3.6-4.5) greater than that of whole blood. Both groups showed significant improvements in IKDC, WOMAC, and VAS scores at 1 month of follow-up. However, only the P-PRP group showed a sustained improvement in clinical outcome measurements at month 24 (P < 0.001). There were statistically significant differences between the P-PRP and sham saline groups in all clinical outcome measurements at each follow-up time point (P < 0.001). The benefit of P-PRP was clinically better in terms of WOMAC-pain, WOMAC-physical function and WOMAC-total at 6, 12, 24, and 60 months of follow-up. No clinically significant differences between treatments were documented in terms of WOMAC-stiffness at any follow-up. A clinically significant difference favoring P-PRP group against saline in terms of IKDC and VAS scores was documented at 6, 12, 24 and 60 months of follow-up. At 6 months after injection, TNF-α and IL-1β levels in synovial fluid were lower in the P-PRP group (P < 0.001). Tibiofemoral cartilage volume decreased by a mean value of 1171 mm³ in the P-PRP group and 2311 mm³ in the saline group over 60 months and the difference between the group was statistically significant (intergroup difference, 1140 mm³, 95% CI - 79 to 1320 mm³; P < 0.001).

CONCLUSIONS

In this randomized clinical trial of patients with KOA, P-PRP was superior to sham saline in treating KOA. P-PRP was effective for achieving at least 24 months of symptom relief and slowing the progress of KOA, with both P-PRP and saline being comparable in safety profiles.

Comparison of screw-home movement between patients with knee osteoarthritis and normal adults

BACKGROUND

Tibial rotation accompanying sagittal movement contains the phenomenon of screw-home movement (SHM) of the knee, which plays an important role in knee stability during extension.

OBJECTIVE

This study aimed to investigate the change of SHM in patients with knee osteoarthritis (OA).

METHODS

Thirty-one sex-matched patients with knee OA and 31 normal subjects were recruited. The total tibial rotation was obtained during knee sagittal movement (extension and flexion) using an inertial measurement unit. The acquired angle of tibial rotation was divided into eight periods. The total tibial rotation and the variation of each period were compared between the OA and control groups. The difference in tibial rotation according to Kellgren-Lawrence (KL) grade was compared.

RESULTS

The total tibial rotation of the OA group decreased compared with the control group during knee extension and flexion (P< 0.001). Variations of tibial rotation were significantly different between groups in all periods (P< 0.001) except for knee extension at 70∘ to 45∘ (P= 0.081). There was no significant difference in tibial rotations among the KA grades of OA patients.

CONCLUSION

We found a reduction in the total tibial rotation and loss of the SHM in the unloaded OA knee. It could be predicted that reduced SHM appeared early in knee OA.

Association between popliteal artery wall thickness and structural progression in patients with symptomatic knee osteoarthritis

OBJECTIVE

There is increasing evidence for the involvement of vascular disease in the pathogenesis of knee osteoarthritis. Popliteal artery wall thickness can be used as a surrogate marker of atherosclerosis. We examined the association between popliteal artery wall thickness and knee cartilage volume in individuals with symptomatic knee osteoarthritis.

METHODS

This prospective cohort study analysed 176 participants from a randomised placebo-controlled trial examining the effect of atorvastatin on structural progression in knee osteoarthritis. The participants underwent magnetic resonance imaging (MRI) of the study knee at baseline and two-year follow-up. Popliteal artery wall thickness and tibial cartilage volume were measured from MRI using validated methods. The top quartile of the rate of tibial cartilage volume loss was defined as rapid progression.

RESULTS

At baseline, every 10% increase in popliteal artery wall thickness was associated with 120.8 mm3 (95% CI 5.4-236.2, p= 0.04) lower of medial tibial cartilage volume and 151.9 mm3 (95% CI 12.1-291.7, p= 0.03) lower of lateral tibial cartilage volume. Longitudinally, for every 10% increase in popliteal artery wall thickness, the annual rate of medial tibial cartilage volume loss was increased by 1.14% (95% CI 0.09%-2.20%, p= 0.03) and there was a 2.28-fold (95% CI 1.07-4.83, p= 0.03) risk of rapid progression of medial tibial cartilage loss, adjusted for age, sex, body mass index, tibial bone area, smoking, vigorous physical activity, and intervention group allocation.

CONCLUSION

The findings support a role for vascular pathology in the progression of knee osteoarthritis. Targeting atherosclerosis has the potential to improve outcomes in knee osteoarthritis.

Irregular types of proximal tibiofibular joint increase the risk of total knee replacement: Data from the osteoarthritis initiative

The study aimed to determine the associations between the morphological types of proximal tibiofibular joint (PTFJ) and the risk of total knee replacement (TKR) in a cohort of participants with progressive osteoarthritis. A nested case-control design was performed in Osteoarthritis Initiative study. The case knees were those with TKR at 24-60 months follow up (cases), and were 1:1 matched with control knees by age, sex, and Kellgren-Lawrence grade at baseline. The morphological type of each PTFJ was identified according to the coronal and sagittal MR images. Conditional logistic regression models were used to examine the association of the PTFJ types with the risk of TKR at baseline and the time point before TKR (T₀ ). A total of 193 case knees at baseline and 148 case knees at T₀ time point had matched controls between 12 and 60 M. Seven types of the PTFJ were identified and classified into three categories: plane, trochoid, and irregular types. The prevalence of the irregular type was higher in case knees than in controls both at baseline (cases vs. controls, 35.8% vs. 26.9%) and at T₀ time point (cases vs. controls, 33.1% vs. 27.0%). The irregular type of the PTFJ at baseline (odds ratio: 1.62, 95% confidence interval: 1.01-2.59) rather than at T₀ time point was significantly associated with increased odds of TKR. The irregular types of the PTFJ at baseline are associated with increased risk of TKR, suggesting PTFJ may play a role in knee osteoarthritis.

Effect of alendronate sodium plus vitamin D3 tablets on knee joint structure and osteoarthritis pain: a multi-center, randomized, double-blind, placebo-controlled study protocol

Background

Osteoarthritis (OA) is a major cause of pain and disability worldwide. Despite the relatively high burden of the disease, the currently available non-surgical treatment options are directed towards symptomatic relief. Therefore, we propose the use of alendronate as a disease modifying agent to help slow and prevent OA. In addition, this study will utilize Whole-Organ Magnetic Resonance Imaging Score (WORMS) to evaluate the structural integrity of cartilage in the study population. High-quality evidence, limited to a few well-conducted randomized trials, highlights contradictory results on the effect of bisphosphonates on knee function and progression of OA. Therefore, a placebo-controlled, randomized trial is needed to evaluate the combined effect of alendronate and vit D on the structure of cartilage utilizing the WORMS score and its ability to treat knee pain in OA patients.

Methods

This multicenter, randomized, double-blinded, placebo-controlled study will evaluate the efficacy and safety of alendronate in early OA. Patients will undergo a 1:1 double-blinded randomization to receive a one-year course of either alendronate sodium vitamin D₃ or placebo. The primary outcome is to compare WORMS score of knee joint at 6 and 12 months between both groups. Secondary endpoints will include WORMS score at 24 months, knee pain, radiographic progression of OA, severity of OA, quality of life, and serum inflammatory biomarkers at different assessment timepoints. To detect a 2.2% difference in cartilage loss between both groups with power of 80%, a sample size of 60 (30 per group) is proposed.

Discussion

This trial will give helpful and high-quality evidence regarding the potential therapeutic role of alendronate sodium vitamin D3, as compared to placebo, in the management of patients with knee OA regarding its role on cartilage loss, radiographic progression of OA, severity of OA, knee pain, quality of life, and inflammatory biomarkers. If proven effective, this intervention would be a great option for providing beneficial outcomes with a reduced cost in this patient population.

Trial registration

This trial was registered on clinicaltrials.gov (registration number: NCT04739592).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05521-4.

Effect of Early Electroacupuncture Combined with Enhanced Recovery after Surgery (ERAS) on Pain Perception and Dysfunction in Patients after Total Knee Arthroplasty (TKA)

Objective

A retrospective case-control study was performed to observe the effect and clinical significance of early electroacupuncture combined with enhanced recovery after surgery (ERAS) on pain perception and dysfunction after total knee arthroplasty (TKA).

Methods

About 100 patients who diagnosed with TKA from February 2019 to April 2021 were enrolled in our hospital. The patients were arbitrarily assigned into control group and study group. The former group was cured with electroacupuncture in the early stage, and the latter group was intervened on the basis of early electroacupuncture combined with the concept of ERAS. The curative effect, the time of getting out of bed for the first time after operation, the time of postoperative rehabilitation, postoperative rehabilitation cost, pain score and knee joint function score, range of motion (ROM) of knee joint, low shear of whole blood viscosity, plasma viscosity, fibrinogen level, and postoperative complications were compared.

Results

There exhibited no statistical difference in clinical data. In terms of the treatment effects, there were 27 cases of markedly effective, 22 cases of effective, and 1 case of ineffective in the study group, and the total effective rate was 98.00%; in the control group, 15 cases were markedly effective, 28 cases were effective, and 13 cases were ineffective, and the total effective rate was 86.00%. Compared to the control group, the total effective rate of the study group was higher (P < 0.05). And the first time to get out of bed and the postoperative rehabilitation time in the study group were lower. Compared to the control group (10113.42 ± 524.83) yuan, the postoperative rehabilitation cost in the study group (12401.71 ± 530.77) yuan was higher. In terms of the scores of VAS and HSS, there exhibited no remarkable difference before treatment (P > 0.05). After treatment, the VAS score lessened and the HSS score augmented the study group VAS score (1.76 ± 0.28); the score in the control group was lower compared to the control group (3.45 ± 0.36), and HSS scoring (83.48 ± 11.23) points higher compared to the control group (65.82 ± 10.44) points (P < 0.05). The ROM of knee joint augmented successively at the 1st, 2nd, 4th, and 8th week after treatment comparison between groups, the ROM of the knee joint in the study group at the 1st, 2nd, 4th, and 8th week was (49.47 ± 3.60)°, (64.38 ± 5.32)°, (86.93 ± 6.72)°, and (104.20 ± 9.11)°, is higher compared to the control group (46.53 ± 3.41)°, (61.52 ± 5.20)°, (78.42 ± 6.45)°, and (98.77 ± 8.67)° (P < 0.05). One day after operation, there exhibited no remarkable difference in whole blood viscosity low shear, plasma viscosity, and fibrinogen level (P > 0.05). However, there exhibited no remarkable difference in plasma viscosity and fibrinogen level at 1 day and 7 days after operation (P > 0.05). Seven days after operation, the whole blood viscosity, plasma viscosity, and fibrinogen in the study group were lower (P < 0.05). The probability of postoperative complications was compared. In the study group, there were 2 cases of limb swelling and pain, 1 case of joint stiffness, and no swelling and pain complicated with deep venous thrombosis, and the total incidence was 6.00%. In the control group, there were 5 cases of limb swelling and pain, 3 cases of joint stiffness, and 3 cases of swelling and pain complicated with deep venous thrombosis, with a total incidence of 22.00%. The incidence of adverse reactions in the study group was lower (χ 2 = 5.317 P < 0.05).

Conclusion

Early electroacupuncture combined with ERAS is of positive significance to the patients after TKA, which can reduce the pain, enhance the function of the knee joint, and promote the ROM of the knee joint, and can effectively shorten the first time out of bed and postoperative rehabilitation time and reduce whole blood viscosity low shear, plasma viscosity, and fibrinogen level, but the overall rehabilitation cost is high, and clinical application should be combined with the actual situation of patients.

Risk factors associated with the occurrence of total knee arthroplasty in patients with knee osteoarthritis: a nested case–control study

Objectives:

The aim of this study was to investigate changes over time in osteoarthritis risk factors most closely associated with the occurrence of total knee arthroplasty (TKA). We hypothesize that the robustness of a longitudinal case–control study will provide new information on the association between changes in various clinical and structural parameters in different time frames before TKA.

Methods:

Cases (195; TKA after cohort entry) and controls (468) matched for age, gender, income, WOMAC pain, Kellgren–Lawrence grade and follow-up duration were from the Osteoarthritis Initiative cohort. Associations between changes in sociodemographic, clinical, imaging and osteoarthritis therapies with the occurrence of TKA were performed using conditional logistic regression analyses.

Results:

Worsening of WOMAC scores (cOR 1.02–1.20, p ⩽ 0.012), KOOS (1.02–1.04, p ⩽ 0.014), knee injuries sustained in the previous 30–40 years (women 2.70, p = 0.034) and valgus alignment (1.10, p = 0.052) were associated with the occurrence of TKA. Also associated with TKA was cartilage volume loss in the lateral (overall 1.76, p = 0.025; women 1.93, p = 0.047) and medial compartments (⩾10%, overall 1.54, p = 0.027; men 2.34, p = 0.008), occurrence of medial meniscal extrusion (overall 1.77, p = 0.046; men 2.86, p = 0.028), and increase in bone marrow lesions (BMLs) for women (1.09, p = 0.048). The association of risk factors with TKA was reinforced when both an increase in WOMAC pain and cartilage volume loss (1.85, p = 0.001) were combined. Pain medication usage, mainly narcotics and intra-articular steroid injections (IASI), was also associated with TKA, with no impact on changes in cartilage loss or structure.

Conclusion:

This study provides new information about gender differences in risk factors associated with the occurrence of TKA. Worsening of valgus alignment, cartilage volume loss in the lateral compartment, BMLs and older injuries are important risk factors in women, while medial compartment cartilage loss and meniscal extrusion are in men. The use of pain medication and IASI although associated was found not causal with TKA.

Low levels of type II collagen formation (PRO-C2) are associated with response to sprifermin: a pre-defined, exploratory biomarker analysis from the FORWARD study

OBJECTIVE

Osteoarthritis (OA) is characterized by the gradual loss of cartilage. Sprifermin, a recombinant FGF18, is being developed as a cartilage anabolic drug. PRO-C2 is a serum marker of type II collagen formation and low levels have been shown to be prognostic of radiographic progression. The aim of the study was to investigate whether the patient groups with either high or low PRO-C2 levels responded differently to sprifermin.

DESIGN

PRO-C2 was measured in synovial fluid (SF) (n = 59) and serum samples (n = 225) from participants of the FORWARD study, a 2-year phase IIb clinical trial testing the efficacy of intra-articular (IA) sprifermin over placebo. The difference between sprifermin and placebo in respect to in change cartilage thickness (measured by quantitative (q) MRI) was analyzed in groups with either high or low (3^rd vs 1^st-2^nd tertiles) baseline serum PRO-C2 levels.

RESULTS

SF levels of PRO-C2 increased over time in response to sprifermin, but not to placebo. In the placebo arm, significantly (p = 0.005) more cartilage was lost in the low vs high PRO-C2 group over the 2-year period. The contrast between sprifermin and placebo was significant (p < 0.001), ranging from 0.104 mm at week 26 to 0.229 mm at week 104 in the low PRO-C2 group. This result was not significant in the high PRO-C2 group ranging from -0.034 to 0.142.

CONCLUSIONS

Patients with low serum PRO-C2 levels lost more cartilage thickness over time and grew more cartilage in response to sprifermin vs a placebo when compared to patients with high PRO-C2 levels.

Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial

IMPORTANCE

Most clinical guidelines do not recommend platelet-rich plasma (PRP) for knee osteoarthritis (OA) because of lack of high-quality evidence on efficacy for symptoms and joint structure, but the guidelines emphasize the need for rigorous studies. Despite this, use of PRP in knee OA is increasing.

OBJECTIVE

To evaluate the effects of intra-articular PRP injections on symptoms and joint structure in patients with symptomatic mild to moderate radiographic medial knee OA.

DESIGN, SETTING, AND PARTICIPANTS

This randomized, 2-group, placebo-controlled, participant-, injector-, and assessor-blinded clinical trial enrolled community-based participants (n = 288) aged 50 years or older with symptomatic medial knee OA (Kellgren and Lawrence grade 2 or 3) in Sydney and Melbourne, Australia, from August 24, 2017, to July 5, 2019. The 12-month follow-up was completed on July 22, 2020.

INTERVENTIONS

Interventions involved 3 intra-articular injections at weekly intervals of either leukocyte-poor PRP using a commercially available product (n = 144 participants) or saline placebo (n = 144 participants).

MAIN OUTCOMES AND MEASURES

The 2 primary outcomes were 12-month change in overall average knee pain scores (11-point scale; range, 0-10, with higher scores indicating worse pain; minimum clinically important difference of 1.8) and percentage change in medial tibial cartilage volume as assessed by magnetic resonance imaging (MRI). Thirty-one secondary outcomes (25 symptom related and 6 MRI assessed; minimum clinically important difference not known) evaluated pain, function, quality of life, global change, and joint structures at 2-month and/or 12-month follow-up.

RESULTS

Among 288 patients who were randomized (mean age, 61.9 [SD, 6.5] years; 169 [59%] women), 269 (93%) completed the trial. In both groups, 140 participants (97%) received all 3 injections. After 12 months, treatment with PRP vs placebo injection resulted in a mean change in knee pain scores of -2.1 vs -1.8 points, respectively (difference, -0.4 [95% CI, -0.9 to 0.2] points; P = .17). The mean change in medial tibial cartilage volume was -1.4% vs -1.2%, respectively (difference, -0.2% [95% CI, -1.9% to 1.5%]; P = .81). Of 31 prespecified secondary outcomes, 29 showed no significant between-group differences.

CONCLUSIONS AND RELEVANCE

Among patients with symptomatic mild to moderate radiographic knee OA, intra-articular injection of PRP, compared with injection of saline placebo, did not result in a significant difference in symptoms or joint structure at 12 months. These findings do not support use of PRP for the management of knee OA.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry Identifier: ACTRN12617000853347.

Associations of blood pressure and arterial stiffness with knee cartilage volume in patients with knee osteoarthritis

OBJECTIVE

To describe the associations of blood pressure and arterial stiffness with knee cartilage volume in patients with knee OA.

METHODS

A secondary analysis was performed on the data from participants in a randomized controlled trial that identified the effects of vitamin D supplementation on knee structures and symptoms among patients with symptomatic knee OA. Brachial and central blood pressure, arterial stiffness indicators and knee cartilage volume were measured at baseline and the 2 year follow-up. Associations were assessed using generalized estimating equations.

RESULTS

Among 231 participants (average age 63.2 years), 48.9% were females. Higher supine systolic and diastolic pressures were significantly associated with lower tibial cartilage volume (systolic: lateral β -6.23, medial β -5.14, total β -11.35 mm3/mmHg; diastolic: lateral β -10.25, medial β -11.29, total β -21.50 mm3/mmHg). Higher supine systolic pressure was associated with lower femoral cartilage volume (lateral β -17.35, total β -28.31 mm3/mmHg). Central systolic pressure and arterial stiffness indicators (including pulse wave velocity, central pulse pressure and peripheral pulse pressure) were largely not associated with knee cartilage volume; however, higher augmentation index was associated with lower tibial and femoral cartilage volume (tibial: medial β -8.24, total β -19.13 mm3/%; femoral: lateral β -23.70, medial β -26.42, total β -50.12 mm3/%).

CONCLUSIONS

Blood pressure and arterial stiffness are associated with knee cartilage volume at several sites in knee OA patients. This supports that blood pressure and arterial stiffness may involve in the progression of knee OA.

Effect of atorvastatin on knee cartilage volume in patients with symptomatic knee osteoarthritis: results from a randomised placebo-controlled trial

OBJECTIVE

To determine whether atorvastatin compared to placebo slows tibial cartilage volume loss in patients with symptomatic knee osteoarthritis in a multicentre, randomised, double-blind, placebo-controlled trial.

METHODS

Participants aged 40-70 years were randomised to oral atorvastatin 40 mg (n=151) or matching placebo (n=153) once daily. Primary endpoint: annual percentage change in tibial cartilage volume assessed using magnetic resonance imaging (MRI) over two years. Pre-specified secondary endpoints: progression of cartilage defects and bone marrow lesions assessed using MRI, and change in Western Ontario and McMaster Universities Osteoarthritis Index pain, stiffness and function over two years.

RESULTS

Of 304 participants (mean age 55.7 years, 55.6% female), 248 (81.6%) completed the trial. Annual change in tibial cartilage volume differed minimally between the atorvastatin and placebo groups (-1.66% vs. -2.17%, difference 0.50%, 95%CI -0.17% to 1.17%). There were no significant differences in progression of cartilage defects (odds ratio 0.86, 95%CI 0.52-1.41) or bone marrow lesions (odds ratio 1.00, 95%CI 0.62-1.63), change in pain [-36.0 vs. -29.5, adjusted difference -2.7, 95%CI -27.1 to 21.7), stiffness (-14.2 vs. -11.8, adjusted difference -0.2, 95%CI -12.2 to 11.8), or function [-89.4 vs. -87.5, adjusted difference 0.3, 95%CI -83.1 to 83.6). Incidence of adverse events was similar in atorvastatin (n=57, 37.7%) and placebo (n=52, 34.0%) groups.

CONCLUSION

Oral atorvastatin 40 mg once daily, compared with placebo, did not significantly reduce cartilage volume loss over two years in patients with symptomatic knee osteoarthritis. These findings do not support use of atorvastatin in the treatment of knee osteoarthritis.

Knee joint biomechanics of patients with unilateral total knee arthroplasty during stationary cycling

Stationary cycling is typically recommended following total knee arthroplasty (TKA) operations. However, knee joint biomechanics during cycling remains mostly unknown for TKA patients. Biomechanical differences between the replaced and non-replaced limb may inform applications of cycling in TKA rehabilitation. The purpose of this study was to examine the knee joint biomechanics of TKA patients during stationary cycling. Fifteen TKA participants cycled at 80 revolutions per minute and workrates of 80 W and 100 W while kinematics (240 Hz) and pedal reaction forces using a pair of instrumented pedals (1200 Hz) were collected. A 2x2 (limb × workrate) repeated measures ANOVA was run with an alpha of 0.05. Peak knee extension moment (KEM, p = 0.034) and vertical pedal reaction force (p = 0.038) were significantly reduced in the replaced limbs compared to non-replaced limbs by 21.3% and 5.3%, respectively. Peak KEM did not change for TKA patients with the increased workrate (p = 0.750). However, both peak hip extension moment (p = 0.009) and ankle plantarflexion moment (p = 0.017) increased due to increased workrate. Patients following TKA showed similar decreases in peak KEM and vertical pedal reaction force in their replaced compared to non-replaced limbs, as previously seen in gait. Patients of TKA may rely on their hip and ankle extensors to increases in workrate. Increasing intensity by 20 W did not exacerbate any inter-limb differences for peak KEM and vertical PRF.

Automated MRI assessment confirms cartilage thickness modification in patients with knee osteoarthritis: post-hoc analysis from a phase II sprifermin study

BACKGROUND

Sprifermin is under investigation as a potential disease-modifying osteoarthritis drug. Previously, 2-year results from the FORWARD study showed significant dose-dependent modification of cartilage thickness in the total femorotibial joint (TFTJ), medial and lateral femorotibial compartments (MFTC, LFTC), and central medial and lateral TFTJ subregions, by quantitative magnetic resonance imaging (qMRI) using manual segmentation.

OBJECTIVE

To determine whether qMRI findings from FORWARD could be reproduced by an independent method of automated segmentation using an identical dataset and similar anatomical regions in a post-hoc analysis.

METHOD

Cartilage thickness was assessed at baseline and 6, 12, 18 and 24 months, using automated cartilage segmentation with active appearance models, a supervised machine learning method. Images were blinded for treatment and timepoint. Treatment effect was assessed by observed and adjusted changes using a linear mixed model for repeated measures.

RESULTS

Based on automated segmentation, statistically significant, dose-dependent structural modification of cartilage thickness was observed over 2 years with sprifermin vs placebo for TFTJ (overall treatment effect and dose response, both P < 0.001), MFTC (P = 0.004 and P = 0.044), and LFTC (both P < 0.001) regions. For highest dose, in the central medial tibial (P = 0.008), central lateral tibial (P < 0.001) and central lateral femoral (P < 0.001) regions.

CONCLUSIONS

Cartilage thickness assessed by automated segmentation provided a consistent dose response in structural modification compared with manual segmentation. This is the first time that two independent quantification methods of image analysis have reached the same conclusions in an interventional trial, strengthening the conclusions that sprifermin modifies structural progression in knee osteoarthritis.

Cost-effectiveness analysis of Coblation versus mechanical shaver debridement in patients following knee chondroplasty

Background

To compare costs and outcomes following knee chondroplasty with Coblation versus mechanical shaver debridement (MSD) in patients with grade III articular cartilage lesions of the knee.

Methods

A decision-analytic model was developed to compare costs and outcomes of the two methods from a US payer perspective. We used published clinical data from a single-center randomized clinical trial (RCT) designed to compare outcomes between Coblation and MSD in patients with grade III articular cartilage lesions of the medial femoral condyle. Following primary knee chondroplasty, patients experienced either treatment success (no additional surgery required) or required a revision over the 4 year follow-up period. Costs associated with the initial chondroplasty, physical therapy sessions through the 6 week postoperative period, and revision rates at 4 years post-surgery were estimated using 2018 US Medicare Physician Fee Schedule. Sensitivity analyses including a 10 year time horizon and threshold analyses were performed to test the robustness of the model.

Results

The estimated total cost per patient was $4614 and $7886 for Coblation and MSD, respectively, resulting in cost-savings of $3272 in favor of Coblation, making it a dominant strategy because of lower costs and improved clinical outcomes. Threshold analysis showed that Coblation remained dominant even when revision rates were assumed to increase from the base case rate of 14–66%. Sensitivity analyses showed that cost-saving results were insensitive to variations in revision rates, number of physical therapy sessions and the time horizon used.

Conclusion

Coblation chondroplasty is a cost-saving procedure compared with MSD in the treatment of patients with grade III articular cartilage lesions of the knee.

Quantitative measurement of cartilage volume with automatic cartilage segmentation in knee osteoarthritis

PURPOSE

To determine the reproducibility of the automatic cartilage segmentation method using a prototype KneeCaP software (version 1.3; Siemens Healthcare, Erlangen, Germany) and to compare the difference in cartilage volume (CV) between the normal knee joint and knee osteoarthritis (KOA) of different degrees by using the above software.

MATERIALS AND METHODS

The study included 62 subjects with knee OA and 29 healthy control subjects. The cartilage lesion patients were divided into a mild-to-moderate OA group (n = 29) and severe OA group (n = 33). Automatic cartilage segmentation was performed on all the subjects, and among them, 19 knee cases were randomly selected to also do the manual cartilage segmentation. Statistical significance was determined with one-way analysis of variance (ANOVA), intraclass correlation coefficient (ICC), and Pearson correlation coefficient. Automatic segmentation was compared with the manual one. The relative cartilage volume percentages of the femur, tibia, and patella in the normal control/mild-to-moderate/severe OA groups were assessed.

RESULTS

Comparing the cartilage volumes derived by manual and automatic segmentation, the ICC value for the knee joint, patella, femur, or tibia was 0.784, 0.815, 0.740, and 0.797. The relative cartilage volume percentages of the femur, tibia, and patella in the normal control/mild-to-moderate/severe OA groups were 57.28%/59.30%/62.45% (femur), 25.35%/23.46%/21.84% (tibia), and 17.37%/17.24%/15.71% (patella), respectively. Compared with the normal control group, the relative tibia cartilage volume percentage was lower in the mild-to-moderate OA group and the severe OA group. Corresponding index showed a similar difference between the mild-to-moderate OA group and the severe OA group (p < 0.001).

CONCLUSION

This study demonstrated that the relative cartilage volume percentage is correlated with the semi-quantitative systems and may be a preferred outcome measure in clinical studies of OA. Automatic cartilage segmentation using KneeCaP delivered reliable results on high-spatial-resolution 3 T MR images for the healthy, mild-moderate OA patients. Key Points • The cartilage automatic segmentation has excellent reproducibility and was not affected by inter-observer variation. • The relative cartilage volume percentage is correlated with the semi-quantitative systems and may be a preferred outcome measure in clinical studies of OA.

Patients with lateral compartment knee osteoarthritis during arthroscopy are at highest risk of subsequent knee arthroplasty

BACKGROUND

Arthroscopic treatment of knee osteoarthritis has declined, in part due to concerns with conversion to arthroplasty. Some studies have investigated the demographic predictors for conversion to arthroplasty, few have assessed the risk factors within the knee itself. Our aim was to analyse the demographics and anatomical wear features of a large cohort of patients undergoing knee arthroscopy.

METHODS

A retrospective analysis of 1760 cases spanning over 17 years undergoing knee arthroscopy was performed. Patients were 36 years or older at time of the index arthroscopy. Each patient received the International Cartilage Regeneration and Joint Preservation Society (ICRS) grade of all regions as well an estimate of the remaining meniscal percentage. Demographic factors as well as intraoperatively collected data were analysed as predictive variables for subsequent conversion to arthroplasty using a multi-step Cox regression analysis.

RESULTS

A total of 102 patients (6.2%) were converted to arthroplasty. Age at arthroscopy (hazard ratio (HR) 1.073; 95% confidence interval (CI) 1.058-1.088) and ICRS grade of the lateral tibial plateau (HR 1.166; 95% CI 1.066-1.276) were statistically significant predicting variables for conversion to arthroplasty.

CONCLUSIONS

The results of this study indicate that higher ICRS grade of the lateral tibial plateau at arthroscopy is the most significant predictor for conversion to knee arthroplasty, with a hazard equal to an increase in age. The absence of these factors does not justify arthroscopic treatment of patients with knee osteoarthritis.

LEVEL OF EVIDENCE

III.

Identification of the most important features of knee osteoarthritis structural progressors using machine learning methods

Objectives:

The aim was to identify the most important features of structural knee osteoarthritis (OA) progressors and classification using machine learning methods.

Methods:

Participants, features and outcomes were from the Osteoarthritis Initiative. Features were from baseline (1107), including articular knee tissues (135) assessed by quantitative magnetic resonance imaging (MRI). OA progressors were ascertained by four outcomes: cartilage volume loss in medial plateau at 48 and 96 months (Prop_CV_48M, 96M), Kellgren–Lawrence (KL) grade ⩾ 2 and medial joint space narrowing (JSN) ⩾ 1 at 48 months. Six feature selection models were used to identify the common features in each outcome. Six classification methods were applied to measure the accuracy of the selected features in classifying the subjects into progressors and non-progressors. Classification of the best features was done using an automatic machine learning interface and the area under the curve (AUC). To prioritize the top five features, sparse partial least square (sPLS) method was used.

Results:

For the classification of the best common features in each outcome, Multi-Layer Perceptron (MLP) achieved the highest AUC in Prop_CV_96M, KL and JSN (0.80, 0.88, 0.95), and Gradient Boosting Machine for Prop_CV_48M (0.70). sPLS showed the baseline top five features to predict knee OA progressors are the joint space width, mean cartilage thickness of the medial tibial plateau and sub-regions and JSN.

Conclusion:

In this comprehensive study using a large number of features (n = 1107) and MRI outcomes in addition to radiological outcomes, we identified the best features and classification methods for knee OA structural progressors. Data revealed baseline X-ray and MRI-based features could predict early OA knee progressors and that MLP is the best classification method.

Predicting knee replacement in participants eligible for disease-modifying osteoarthritis drug treatment with structural endpoints

OBJECTIVE

Evaluate associations between 2-year change in radiographic or quantitative magnetic resonance imaging (qMRI) structural measures, and knee replacement (KR), within a subsequent 7-year follow-up period.

METHOD

Participants from the Osteoarthritis Initiative were selected based on potential eligibility criteria for a disease-modifying osteoarthritis (OA) drug trial: Kellgren-Lawrence grade 2 or 3; medial minimum joint space width (mJSW) ≥2.5 mm; knee pain at worst 4-9 in the past 30 days on an 11-point scale, or 0-3 if medication was taken for joint pain; and availability of structural measures over 2 years. Mean 2-year change in structural measures was estimated and compared with two-sample independent t-tests for KR and no KR. Area under the receiver operating characteristic curve (AUC) was estimated using 2-year change in structural measures for prediction of future KR outcomes.

RESULTS

Among 627 participants, 107 knees underwent KR during a median follow-up of 6.7 years after the 2-year imaging period. Knees that received KR during follow-up had a greater mean loss of cartilage thickness in the total femorotibial joint and medial femorotibial compartment on qMRI, as well as decline in medial fixed joint space width on radiographs, compared with knees that did not receive KR. These imaging measures had similar, although modest discrimination for future KR (AUC 0.62, 0.60, and 0.61, respectively).

CONCLUSIONS

2-year changes in qMRI femorotibial cartilage thickness and radiographic JSW measures had similar ability to discriminate future KR in participants with knee OA, suggesting that these measures are comparable biomarkers/surrogate endpoints of structural progression.

Predicting Total Knee Replacement from Symptomology and Radiographic Structural Change Using Artificial Neural Networks-Data from the Osteoarthritis Initiative (OAI)

The aim of the study was to longitudinally investigate symptomatic and structural factors prior to total knee replacement (TKR) surgery in order to identify influential factors that can predict a patient's need for TKR surgery. In total, 165 participants (60% females; 64.5 ± 8.4 years; 29.7 ± 4.7 kg/m²) receiving a TKR in any of both knees within a four-year period were analyzed. Radiographic change, knee pain, knee function and quality of life were annually assessed prior to the TKR procedure. Self-learning artificial neural networks were applied to identify driving factors for the surgical procedure. Significant worsening of radiographic structural change was observed prior to TKR (p ≤ 0.0046), whereas knee symptoms (pain, function, quality of life) worsened significantly only in the year prior to the TKR procedure. By using our prediction model, we were able to predict correctly 80% of the classified individuals to undergo TKR surgery with a positive predictive value of 84% and a negative predictive value of 73%. Our prediction model offers the opportunity to assess a patient's need for TKR surgery two years in advance based on easily available patient data and could therefore be used in a primary care setting.

Effect of Intravenous Zoledronic Acid on Tibiofemoral Cartilage Volume Among Patients With Knee Osteoarthritis With Bone Marrow Lesions: A Randomized Clinical Trial

IMPORTANCE

A proof-of-principle study suggested that intravenous zoledronic acid may reduce knee pain and the size of bone marrow lesions in people with knee osteoarthritis, but data from large trials are lacking.

OBJECTIVE

To determine the effects of intravenous zoledronic acid on knee cartilage volume loss in patients with symptomatic knee osteoarthritis and bone marrow lesions.

DESIGN, SETTING, AND PARTICIPANTS

A 24-month multicenter, double-blind placebo-controlled randomized clinical trial conducted at 4 sites in Australia (1 research center and 3 hospitals). Adults aged 50 years or older with symptomatic knee osteoarthritis and subchondral bone marrow lesions detected by magnetic resonance imaging (MRI) were enrolled from November 2013 through September 2015. The final date of follow-up was October 9, 2017.

INTERVENTIONS

Intravenous infusion with either 5 mg of zoledronic acid in a 100-mL saline solution (n = 113) or a placebo saline solution (n = 110) at baseline and 12 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was absolute change in tibiofemoral cartilage volume assessed using MRI over 24 months (the minimum clinically important difference [MCID] has not been established). Three prespecified secondary outcomes were change in knee pain assessed by a visual analog scale (0 [no pain] to 100 [unbearable pain]; MCID, 15) and the Western Ontario and McMaster Universities Osteoarthritis Index (0 [no pain] to 500 [unbearable pain]; MCID, 75) over 3, 6, 12, 18, and 24 months and change in bone marrow lesion size over 6 and 24 months (the MCID has not been established).

RESULTS

Of 223 participants enrolled (mean age, 62.0 years [SD, 8.0 years]; 52% were female), 190 (85%) completed the trial. Change in tibiofemoral cartilage volume was not significantly different between the zoledronic acid group and the placebo group over 24 months (-878 mm3 vs -919 mm3; between-group difference, 41 mm3 [95% CI, -79 to 161 mm3]; P = .50). No significant between-group differences were found for any of the prespecified secondary outcomes, including changes in knee pain assessed by a visual analog scale (-11.5 in the zoledronic acid group vs -16.8 in the placebo group; between-group difference, 5.2 [95% CI, -2.3 to 12.8]; P = .17), changes in knee pain assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (-37.5 vs -58.0, respectively; between-group difference, 20.5 [95% CI, -11.2 to 52.2]; P = .21), and changes in bone marrow lesion size (-33 mm2 vs -6 mm2; between-group difference, -27 mm2 [95% CI, -127 to 73 mm2]; P = .60) over 24 months. Adverse events were more common with zoledronic acid than with placebo (96% vs 83%, respectively) and consisted mainly of acute reactions (defined as symptoms within 3 days of administration of infusion; 87% vs 56%).

CONCLUSIONS AND RELEVANCE

Among patients with symptomatic knee osteoarthritis and bone marrow lesions, yearly zoledronic acid infusions, compared with placebo, did not significantly reduce cartilage volume loss over 24 months. These findings do not support the use of zoledronic acid in the treatment of knee osteoarthritis.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12613000039785.

The ratio adipsin/MCP-1 is strongly associated with structural changes and CRP/MCP-1 with symptoms in obese knee osteoarthritis subjects: data from the Osteoarthritis Initiative

OBJECTIVE

There is a need to identify reliable biomarkers that can predict knee osteoarthritis (OA) progression. We investigated a panel of adipokines and some related inflammatory factors alone and their ratios for their associative value at assessing cartilage volume loss over time and symptoms in obese [High body mass index (BMI)] and non-obese (Low BMI) OA subjects.

DESIGN

Human OA serum was from the Osteoarthritis Initiative Progression subcohort. Baseline levels of adiponectin (high and low molecular weight forms), adipsin, chemerin, leptin, visfatin, C-reactive protein (CRP), interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) were evaluated with specific assays. Cartilage volume was assessed at baseline and 48 months by quantitative magnetic resonance imaging (MRI), and symptoms using baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. Data were analysed by linear regression with confounding factors at baseline, followed by multiple comparison adjustment.

RESULTS

The levels of the nine biomarkers and their ratios (36) were studied. Among High BMI subjects, only the ratio adipsin/MCP-1 was associated with cartilage volume loss over time in the lateral compartment [β, -2.95; 95% confidence interval (CI), -4.42, -1.49; P = 0.010], whereas MCP-1 was associated with WOMAC pain (-1.74; -2.75, -0.73; P = 0.030) and the ratio CRP/MCP-1 with WOMAC pain (0.76; 0.37, 1.14; P = 0.023), function (2.43; 1.20, 3.67; P = 0.020) and total (3.29; 1.58, 5.00; P = 0.027). No associations were found for biomarkers or ratios in Low BMI OA.

CONCLUSION

In this study, the ratio adipsin/MCP-1 was found to be associated with the knee structural changes and that of CRP/MCP-1 with symptoms in obese OA subjects. Our data further underline the relevance of ratios as biomarkers to a stronger association to OA progression and symptoms.

Association between metabolic syndrome and knee structural change on MRI

Objective

To examine the association of metabolic syndrome (MetS) and its components with knee cartilage volume loss and bone marrow lesion (BML) change.

Methods

Longitudinal data on 435 participants from a population-based cohort study were analysed. Blood pressure, glucose, triglycerides and high-density lipoprotein (HDL) were collected. MetS was defined based on the National Cholesterol Education Program–Adult Treatment Panel III criteria. MRI of the right knee was performed to measure cartilage volume and BML. Radiographic knee OA was assessed by X-ray and graded using the Altman atlas for osteophytes and joint space narrowing.

Results

Thirty-two percent of participants had MetS and 60% had radiographic knee OA. In multivariable analysis, the following were independently associated with medial tibial cartilage volume loss: MetS, β = −0.30%; central obesity, β = −0.26%; and low HDL, β = −0.25% per annum. MetS, hypertriglyceridaemia and low HDL were also associated with higher risk of BML size increase in the medial compartment (MetS: relative risk 1.72, 95% CI 1.22, 2.43; hypertriglyceridaemia: relative risk 1.43, 95% CI 1.01, 2.02; low HDL: relative risk 1.67, 95% CI 1.18, 2.36). After further adjustment for central obesity or BMI, MetS and low HDL remained statistically significant for medial tibial cartilage volume loss and BML size increase. The number of components of MetS correlated with greater cartilage volume loss and BML size increase (both P for trend <0.05). There were no statistically significant associations in the lateral compartment.

Conclusion

MetS and low HDL are associated with medial compartment cartilage volume loss and BML size increase, suggesting that targeting these factors has the potential to prevent or slow knee structural change.

Tibiofemoral joint structural change from 2.5 to 4.5 years following ACL reconstruction with and without combined meniscal pathology

Background

People who have had anterior cruciate ligament reconstruction (ACLR) are at a high risk of developing tibiofemoral joint (TFJ) osteoarthritis (OA), with concomitant meniscal injury elevating this risk. This study aimed to investigate OA-related morphological change over 2 years in the TFJ among individuals who have undergone ACLR with or without concomitant meniscal pathology and in healthy controls. A secondary aim was to examine associations of baseline TFJ cartilage defects and bone marrow lesions (BML) scores with tibial cartilage volume change in ACLR groups.

Methods

Fifty seven ACLR participants aged 18–40 years (32 isolated ACLR, 25 combined meniscal pathology) underwent knee magnetic resonance imaging (MRI) 2.5 and 4.5 years post-surgery. Nine healthy controls underwent knee MRI at the ~ 2-year intervals. Tibial cartilage volume, TFJ cartilage defects and BMLs were assessed from MRI.

Results

For both ACLR groups, medial and lateral tibial cartilage volume increased over 2 years (P <  0.05). Isolated ACLR group had greater annual percentage increase in lateral tibial cartilage volume compared with controls and with the combined group (P = 0.03). Cartilage defects remained unchanged across groups. Both ACLR groups showed more lateral tibia BML regression compared with controls (P = 0.04). Baseline cartilage defects score was positively associated with cartilage volume increase at lateral tibia (P = 0.002) while baseline BMLs score was inversely related to medial tibia cartilage volume increase (P = 0.001) in the pooled ACLR group.

Conclusions

Tibial cartilage hypertrophy was apparent in ACLR knees from 2.5 to 4.5 years post-surgery and was partly dependent upon meniscal status together with the nature and location of the underlying pathology at baseline. Magnitude and direction of change in joint pathologies (i.e., cartilage defects, BMLs) were less predictable and either remained stable or improved over follow-up.

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2687-9) contains supplementary material, which is available to authorized users.

Precision, Reliability, and Responsiveness of a Novel Automated Quantification Tool for Cartilage Thickness: Data from the Osteoarthritis Initiative

Objective.

Accurate automated segmentation of cartilage should provide rapid reliable outcomes for both epidemiological studies and clinical trials. We aimed to assess the precision and responsiveness of cartilage thickness measured with careful manual segmentation or a novel automated technique.

Methods.

Agreement of automated segmentation was assessed against 2 manual segmentation datasets: 379 magnetic resonance images manually segmented in-house (training set), and 582 from the Osteoarthritis Initiative with data available at 0, 1, and 2 years (biomarkers set). Agreement of mean thickness was assessed using Bland-Altman plots, and change with pairwise Student t test in the central medial femur (cMF) and tibia regions (cMT). Repeatability was assessed on a set of 19 knees imaged twice on the same day. Responsiveness was assessed using standardized response means (SRM).

Results.

Agreement of manual versus automated methods was excellent with no meaningful systematic bias (training set: cMF bias 0.1 mm, 95% CI ± 0.35; biomarkers set: bias 0.1 mm ± 0.4). The smallest detectable difference for cMF was 0.13 mm (coefficient of variation 3.1%), and for cMT 0.16 mm(2.65%). Reported change using manual segmentations in the cMF region at 1 year was −0.031 mm (95% CI −0.022, −0.039), p < 10−4, SRM −0.31 (−0.23, −0.38); and at 2 years was −0.071 (−0.058, −0.085), p < 10−4, SRM −0.43 (−0.36, −0.49). Reported change using automated segmentations in the cMF at 1 year was −0.059 (−0.047, −0.071), p < 10−4, SRM −0.41 (−0.34, −0.48); and at 2 years was −0.14 (−0.123, −0.157, p < 10−4, SRM −0.67 (−0.6, −0.72).

Conclusion.

A novel cartilage segmentation method provides highly accurate and repeatable measures with cartilage thickness measurements comparable to those of careful manual segmentation, but with improved responsiveness.

Greater magnitude tibiofemoral contact forces are associated with reduced prevalence of osteochondral pathologies 2-3 years following anterior cruciate ligament reconstruction

PURPOSE

External loading of osteoarthritic and healthy knees correlates with current and future osteochondral tissue state. These relationships have not been examined following anterior cruciate ligament reconstruction. We hypothesised greater magnitude tibiofemoral contact forces were related to increased prevalence of osteochondral pathologies, and these relationships were exacerbated by concomitant meniscal injury.

METHODS

This was a cross-sectional study of 100 individuals (29.7 ± 6.5 years, 78.1 ± 14.4 kg) examined 2-3 years following hamstring tendon anterior cruciate ligament reconstruction. Thirty-eight participants had concurrent meniscal pathology (30.6 ± 6.6 years, 83.3 ± 14.3 kg), which included treated and untreated meniscal injury, and 62 participants (29.8 ± 6.4 years, 74.9 ± 13.3 kg) were free of meniscal pathology. Magnetic resonance imaging of reconstructed knees was used to assess prevalence of tibiofemoral osteochondral pathologies (i.e., cartilage defects and bone marrow lesions). A calibrated electromyogram-driven neuromusculoskeletal model was used to predict medial and lateral tibiofemoral compartment contact forces from gait analysis data. Relationships between contact forces and osteochondral pathology prevalence were assessed using logistic regression models.

RESULTS

In patients with reconstructed knees free from meniscal pathology, greater medial contact forces were related to reduced prevalence of medial cartilage defects (odds ratio (OR) = 0.7, Wald χ²(2) = 7.9, 95% confidence interval (CI) = 0.50-95, p = 0.02) and medial bone marrow lesions (OR = 0.8, Wald χ²(2) = 4.2, 95% CI = 0.7-0.99, p = 0.04). No significant relationships were found in lateral compartments. In reconstructed knees with concurrent meniscal pathology, no relationships were found between contact forces and osteochondral pathologies.

CONCLUSIONS

In patients with reconstructed knees free from meniscal pathology, increased contact forces were associated with fewer cartilage defects and bone marrow lesions in medial, but not, lateral tibiofemoral compartments. No significant relationships were found between contact forces and osteochondral pathologies in reconstructed knees with meniscal pathology for any tibiofemoral compartment. Future studies should focus on determining longitudinal effects of contact forces and changes in osteochondral pathologies.

LEVEL OF EVIDENCE

IV.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Intra-articular treatment options for knee osteoarthritis

Intra-articular drug delivery has a number of advantages over systemic administration; however, for the past 20 years, intra-articular treatment options for the management of knee osteoarthritis (OA) have been limited to analgesics, glucocorticoids, hyaluronic acid (HA) and a small number of unproven alternative therapies. Although HA and glucocorticoids can provide clinically meaningful benefits to an appreciable number of patients, emerging evidence indicates that the apparent effectiveness of these treatments is largely a result of other factors, including the placebo effect. Biologic drugs that target inflammatory processes are used to manage rheumatoid arthritis, but have not translated well into use in OA. A lack of high-level evidence and methodological limitations hinder our understanding of so-called 'stem' cell therapies and, although the off-label administration of intra-articular cell therapies (such as platelet-rich plasma and bone marrow aspirate concentrate) is common, high-quality clinical data are needed before these treatments can be recommended. A number of promising intra-articular treatments are currently in clinical development in the United States, including small-molecule and biologic therapies, devices and gene therapies. Although the prospect of new, non-surgical treatments for OA is exciting, the benefits of new treatments must be carefully weighed against their costs and potential risks.

Full-Thickness Cartilage Defects Are Important Independent Predictive Factors for Progression to Total Knee Arthroplasty in Older Adults with Minimal to Moderate Osteoarthritis: Data from the Osteoarthritis Initiative

BACKGROUND

Knee osteoarthritis (OA) severity on radiographs is not a reliable predictor of symptom severity. The purpose of this study was to determine whether full-thickness defects or OA grade are predictive of the progression to total knee arthroplasty in older patients without end-stage arthritis.

METHODS

This study included 1,319 adults aged 45 to 79 years (mean age [and standard deviation], 61.0 ± 9.2 years) who were enrolled in the Osteoarthritis Initiative, a prospective multicenter study with median 9-year follow-up data. All participants had Kellgren-Lawrence grade-0 to 3 (no to moderate) OA on bilateral radiographs; patients with grade-4 (severe) OA were excluded. The presence and total surface area of full-thickness cartilage defects on the tibia or the weight-bearing portion of the femoral condyle were determined. The risk of total knee arthroplasty due to defect presence and size as well as OA grade was determined with Cox proportional-hazards modeling after controlling for baseline variables including, but not limited to, age, sex, race, weight, knee alignment, symptom severity, quality-of-life scores, and activity level.

RESULTS

Four hundred and ninety-six patients (37.6%) had full-thickness defects. The incidence of knee arthroplasty was 0.57% per person-year for adults without a full-thickness defect and 2.15% for those with a defect. After adjusting for confounders, the presence of a full-thickness defect increased the risk of total knee arthroplasty regardless of OA grade, with higher risk demonstrated for larger (≥2 cm) defects (hazard ratio [HR] = 5.27 [95% confidence interval (CI) = 2.70 to 10.3]; p < 0.001) compared with smaller (<2 cm) defects (HR = 2.65 [95% CI = 1.60 to 4.37]; p < 0.001). Compared with nonarthritic knees (grade 0 to 1), mild arthritis (grade 2) did not increase total knee arthroplasty risk (HR = 0.71 [95% CI = 0.31 to 1.60]); moderate arthritis (grade 3) increased total knee arthroplasty risk in adults without a full-thickness defect (HR = 3.15 [95% CI = 1.34 to 7.40]; p = 0.009) but not in adults with a defect (HR = 0.64 [95% CI = 0.28 to 1.49]; p = 0.30).

CONCLUSIONS

Full-thickness cartilage defects were a major determinant of future knee arthroplasty in older adults with minimal to moderate OA, even after adjusting for baseline knee symptom severity. Baseline radiographic severity grade was only associated with future total knee arthroplasty risk in the absence of a full-thickness defect.

LEVEL OF EVIDENCE

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

Baseline knee joint effusion and medial femoral bone marrow edema, in addition to MRI-based T2 relaxation time and texture measurements of knee cartilage, can help predict incident total knee arthroplasty 4-7 years later: data from the Osteoarthritis Initiative

OBJECTIVE

To evaluate if baseline pathological knee conditions as assessed via single features of the MR-based Whole-Organ Magnetic Resonance Imaging Scoring (WORMS), standard T2, and T2 gray-level co-occurrence matrix (GLCM) texture parameters of knee cartilage can serve as potential long-term radiological predictors of incident total knee arthroplasty (TKA) 4-7 years later.

MATERIALS AND METHODS

Baseline 3-T knee MRIs of 309 subjects from the Osteoarthritis Initiative (n = 81 TKA cases, with right-knee TKA 4-7 years after enrolment, and n = 228 TKA-free matched controls) were evaluated for the presence and severity of pathological knee conditions via modified WORMS. Knee cartilage was segmented and standard T2 cartilage and T2 GLCM texture measures (contrast, variance) were computed. Statistical analysis employed conditional logistic regression.

RESULTS

We found that a one-point increase on the joint effusion scale, the bone marrow edema scale or on the cartilage lesion scale at baseline predicted incident TKA (ORs: 2.45, 1.65, and 1.37 respectively (p ≤ 0.003)). For T2 cartilage measurements, we observed that in the lateral femur, a 1-SD increase in T2 relaxation time yielded a 28% increase in the odds of TKA (1.28 [1.09-1.643], p = 0.046). When looking at cartilage texture, we similarly noted that a 1-SD increase in the cartilage texture parameter "contrast" was associated with a 33-40% increased risk of incident TKA in the lateral femur and tibia (0.003 ≤ p ≤ 0.021), as was a 1-SD increase in the texture parameter "variance" in the lateral femur (p = 0.002).

CONCLUSION

Radiological evaluation of standard knee MR images via single WORMS features and T2 standard and texture analysis at baseline can help predict the patient's individual risk for an incident TKA 4-7 years later.

Association of adiposity measures in childhood and adulthood with knee cartilage thickness, volume and bone area in young adults

OBJECTIVE

To describe the associations of childhood and adulthood adiposity measures with knee cartilage thickness, volume and bone area in young adults.

METHODS

Childhood and adulthood adiposity measures (weight, height, waist circumference and hip circumference) of 186 participants were collected in 1985 (aged 7-15 years) and during 2004-2006 (aged 26-36 years). Knee magnetic resonance imaging was conducted during 2008-2010 (aged 31-41 years) and cartilage thickness, volume and bone area were measured using a quantitative approach (Chondrometrics, Germany). Linear regressions were used to examine the above associations.

RESULTS

The prevalence of overweight was 7.6% in childhood and 42.1% in adulthood. Childhood weight (β = - 5.57 mm²/kg) and body mass index (BMI) (β = - 11.55 mm²/kg/m²) were negatively associated with adult patellar bone area, whereas adult weight was positively associated with bone area in medial femorotibial compartment (MFTC) (β = 3.37 mm²/kg) and lateral femorotibial compartment (LFTC) (β = 2.08 mm²/kg). Adult waist-hip ratio (WHR) was negatively associated with cartilage thickness (MFTC: β = - 0.011; LFTC: β = - 0.012 mm/0.01 unit), volume (Patella: β = - 20.97; LFTC: β = - 21.71 mm³/0.01 unit) and bone area (Patella: β = - 4.39 mm²/0.01 unit). The change in WHR z-scores from childhood to adulthood was negatively associated with cartilage thickness (MFTC: β = - 0.056 mm), volume (patella: - 89.95; LFTC: - 93.98 mm³), and bone area (patella: - 20.74 mm²). All p-values < 0.05.

CONCLUSIONS

Childhood weight and BMI were negatively but adult weight was positively associated with adult bone area. Adult WHR and the change in WHR from childhood to adulthood were negatively associated with cartilage thickness, volume, and bone area. These suggest early-life adiposity measures may affect knee structures in young adults.

Development and validation of prediction models to estimate risk of primary total hip and knee replacements using data from the UK: two prospective open cohorts using the UK Clinical Practice Research Datalink

Objectives

The ability to efficiently and accurately predict future risk of primary total hip and knee replacement (THR/TKR) in earlier stages of osteoarthritis (OA) has potentially important applications. We aimed to develop and validate two models to estimate an individual’s risk of primary THR and TKR in patients newly presenting to primary care.

Methods

We identified two cohorts of patients aged ≥40 years newly consulting hip pain/OA and knee pain/OA in the Clinical Practice Research Datalink. Candidate predictors were identified by systematic review, novel hypothesis-free ‘Record-Wide Association Study’ with replication, and panel consensus. Cox proportional hazards models accounting for competing risk of death were applied to derive risk algorithms for THR and TKR. Internal–external cross-validation (IECV) was then applied over geographical regions to validate two models.

Results

45 predictors for THR and 53 for TKR were identified, reviewed and selected by the panel. 301 052 and 416 030 patients newly consulting between 1992 and 2015 were identified in the hip and knee cohorts, respectively (median follow-up 6 years). The resultant model C-statistics is 0.73 (0.72, 0.73) and 0.79 (0.78, 0.79) for THR (with 20 predictors) and TKR model (with 24 predictors), respectively. The IECV C-statistics ranged between 0.70–0.74 (THR model) and 0.76–0.82 (TKR model); the IECV calibration slope ranged between 0.93–1.07 (THR model) and 0.92–1.12 (TKR model).

Conclusions

Two prediction models with good discrimination and calibration that estimate individuals’ risk of THR and TKR have been developed and validated in large-scale, nationally representative data, and are readily automated in electronic patient records.

Effects of long-term exercise therapy on knee joint structure in people with knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVE

To investigate effects of long-term exercise therapy for people with knee osteoarthritis (OA) on radiographic disease severity and cartilage integrity (primary outcomes) as well as severity of bone marrow lesions (BMLs), synovitis and/or effusion (secondary outcomes).

METHODS

We sourced randomized controlled trials in people with clinical and/or radiographic OA investigating the effect of land-based exercise therapy of > 6 months on radiographic disease severity and magnetic resonance imaging outcomes of cartilage integrity (morphology or composition) as well as BML, synovitis and/or effusion severity, when compared to no exercise. Two independent reviewers extracted data and assessed risk of bias. Random-effects meta-analysis was used to pool standardised mean differences (SMD) (95% confidence intervals (CI)) or odds ratios (OR) (95% CI) and estimate heterogeneity (I², %). Quality of the pooled body of evidence was rated implementing the GRADE approach. Studies unsuitable for meta-analysis were summarized in a best-evidence synthesis.

RESULTS

Meta-analysis showed moderate quality evidence of no treatment effect on tibiofemoral radiographic disease severity ((SMD) 95% (CI): 0.06 (-0.07, 0.20), I²= 0%) and low-quality evidence of no effect on tibiofemoral cartilage morphology (SMD (95%): 0.06 (-0.20, 0.36), I²= 0%). Low quality evidence revealed no treatment effect on the odds of change in synovitis ((OR) (95% CI): 0.90 (0.51,1.60), I²= 0%) and effusion ((OR (95% CI): 0.88 (0.64, 1.20), I²= 0%), but greater odds of tibiofemoral BMLs worsening (OR (95% CI): 1.90 (1.11, 3.26), I²= 0%). In best-evidence synthesis, limited evidence was found for changes in patellar cartilage composition following exercise in women with mild knee OA compared to no exercise, but not for tibiofemoral cartilage.

CONCLUSION

Long-term exercise therapy did not change tibiofemoral radiographic disease severity, cartilage morphology or synovitis/effusion, but may slightly increase the likelihood for increased BML severity. Overall, meta-analysis findings were limited in directness and precision and restricted to relatively imprecise effect estimates in people who were obese on average. Limited evidence suggested some protective effects on patellar cartilage composition.

Impact of oral osteoarthritis therapy usage among other risk factors on knee replacement: a nested case-control study using the Osteoarthritis Initiative cohort

BACKGROUND

The aim of this study was to measure the association between exposure to commonly used oral osteoarthritis (OA) therapies and relevant confounding risk factors on the occurrence of knee replacement (KR), using the Osteoarthritis Initiative (OAI) database.

METHODS

In this nested case-control design study, participants who had a KR after cohort entry were defined as "cases" and were matched with up to four controls for age, gender, income, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, Kellgren-Lawrence grade, and duration of follow up. Exposure to oral OA therapies (acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), cyclooxygenase-2 (COX-2) inhibitors, narcotics, and glucosamine/chondroitin sulfate) was determined within the 3 years prior to the date of the KR. Conditional regression analyses were performed to estimate the association between KR and exposure to oral OA therapies and other potential confounding risk factors.

RESULTS

A total of 218 participants who underwent a KR (cases) were matched to 540 controls. The median time to KR was 4.3 years among cases. The majority in both groups were Caucasian with mean age of 69 years and 61% were female. Numerically, cases were more exposed to acetaminophen, NSAIDs, and COX-2 inhibitors. Exposure to narcotics and glucosamine/chondroitin sulfate was relatively similar between cases and controls. No significant association was found between the occurrence of KR and exposure to any of the oral OA therapies within the 3 years prior to KR. A significantly higher occurrence of KR was found in Caucasian subjects (OR 1.84; 95% CI, 1.13-2.99; p = 0.015) and subjects with body mass index (BMI) ≥ 27 kg/m² (OR 1.65; 95% CI, 1.06-2.58; p = 0.027).

CONCLUSION

This study provides evidence that the main risk factors leading to KR are disease severity, symptoms and high BMI. Importantly, exposure to oral OA therapies was not associated with the occurrence of KR.

Efficacy of intra-articular injections of platelet-rich plasma as a symptom- and disease-modifying treatment for knee osteoarthritis - the RESTORE trial protocol

Background

Knee osteoarthritis (OA) causes substantial pain, physical dysfunction and impaired quality of life. There is no cure for knee OA, and for some people, the disease may involve progressive symptomatic and structural deterioration over time. Platelet-rich plasma (PRP) is a therapeutic agent that aims to address underlying biological processes responsible for OA pathogenesis. As such, it has the potential to improve both symptoms and joint structure. The aim of this clinical trial is to determine whether a series of injections of PRP into the knee joint will lead to a significantly greater reduction in knee pain, and less loss of medial tibial cartilage volume over 12 months when compared to a series of placebo saline injections in people with knee OA.

Methods

This will be a two-group, superiority, randomised, participant-, interventionist- and assessor-blinded, placebo-controlled trial. Two hundred and eighty-eight participants aged over 50 years with painful knee OA and mild to moderate structural change on x-ray (Kellgren and Lawrence grade 2 and 3) will be randomly allocated to receive either three PRP injections or three normal saline injections into the knee joint at weekly intervals. The primary outcomes will be 12-month change in average overall knee pain severity (numeric rating scale) and medial tibial cartilage volume (magnetic resonance imaging (MRI)). Secondary outcomes include additional measures of knee pain and other symptoms, function in daily living and sport and recreation, quality of life, participant-perceived global ratings of change, and other MRI structural outcomes including meniscal and cartilage morphology, synovitis, effusion, bone marrow lesions and cartilage defects. A range of additional measures will be recorded, and a separate health economic evaluation will be performed.

Discussion

The findings from this study will help determine whether PRP improves both clinical and structural knee OA outcomes over 12 months when compared to a series of placebo saline injections.

Trial registration

Australian New Zealand Clinical Trials Registry reference: ACTRN12617000853347. Prospectively registered 9th of June 2017.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2205-5) contains supplementary material, which is available to authorized users.

A protocol for a multicentre, randomised, double-blind, placebo-controlled trial to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change and knee pain over 24 months in knee osteoarthritis patients - ZAP2

BACKGROUND

Bisphosphonates are a class of drugs that slow bone loss and are a promising candidate to treat knee osteoarthritis (OA) patients. In a pilot study, we demonstrated that zoledronic acid reduced knee pain and size of subchondral bone marrow lesions (BMLs) over 6 months in knee OA patients with significant knee pain and BMLs. A longer, larger study is required to assess whether decreases in BML size will translate to reductions in cartilage loss over time. We are currently conducting a multicentre, randomised, double-blind, placebo-controlled trial over 24 months that aims to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change (assessed using magnetic resonance imaging (MRI)) and knee pain in knee OA patients.

METHODS

Two hundred sixty-four patients with clinical knee OA, significant knee pain and subchondral BMLs present on MRI will be recruited in Hobart, Melbourne, Sydney and Adelaide. They will be randomly allocated to the two arms of the study, receiving an annual identical intravenous infusion of either 100 mL of fluid containing zoledronic acid (5 mg/100 mL) or placebo (0.9% NaCl 100 mL), at baseline and 1 year later. MRI of the study knee will be performed at screening, month 6 and 24. Knee structure, symptoms and function will be assessed using validated methods. The primary outcome is absolute change in tibiofemoral cartilage volume (mm3) over 24 months. Secondary outcomes include improvement in knee pain over 3, 6, 12, 18, and 24 months and reductions in BML size over 6 and 24 months. The primary analyses will be intention-to-treat analyses of primary and secondary outcomes. Per protocol analyses will be performed as the secondary analyses.

DISCUSSION

This study will provide high-quality evidence to assess whether zoledronic acid has a novel disease modifying effect in OA by slowing cartilage loss and reducing pain. If zoledronic acid proves effective, it suggests great potential for cost savings through a delay or reduced need for joint replacement surgery, and potential for great improvements in quality of life for OA suffers.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12613000039785 , registered on 14 January 2013.

Clinical Management in Early OA

Knee osteoarthritis affects an important percentage of the population throughout their life. Several factors seem to be related to the development of knee osteoarthritis including genetic predisposition, gender, age, meniscal deficiency, lower limb malalignments, joint instability, cartilage defects, and increasing sports participation. The latter has contributed to a higher prevalence of early onset of knee osteoarthritis at younger ages with this active population demanding more consistent and durable outcomes. The diagnosis is complex and the common signs and symptoms are often cloaked at these early stages. Classification systems have been developed and are based on the presence of knee pain and radiographic findings coupled with magnetic resonance or arthroscopic evidence of early joint degeneration. Nonsurgical treatment is often the first-line option and is mainly based on daily life adaptations, weight loss, and exercise, with pharmacological agents having only a symptomatic role. Surgical treatment shows positive results in relieving the joint symptomatology, increasing the knee function and delaying the development to further degenerative stages. Biologic therapies are an emerging field showing early promising results; however, further high-level research is required.