Correlation of the development of knee pain with enlarging bone marrow lesions on magnetic resonance imaging

OBJECTIVE: Results of cross-sectional studies have suggested that bone marrow lesions (BMLs) visualized on magnetic resonance imaging (MRI) are related to knee pain, but no longitudinal studies have been done. This study was undertaken to determine whether enlarging BMLs are associated with new knee pain. METHODS: Subjects ages 50-79 years with knee osteoarthritis (OA) or at high risk of knee OA were asked twice at baseline about the presence of knee pain, aching, or stiffness (classified as frequent knee pain) on most days; absence of knee pain was the baseline eligibility criterion. At 15 months' followup, subjects were again queried twice about frequent knee pain. A case knee was defined as absence of knee pain at baseline but presence of knee pain both times at followup. Controls were selected randomly from among knees with absence of pain at baseline. All MR images were scored for volume of BMLs in the medial, lateral, and patellofemoral compartments. We focused on the maximal change in BML score among the knee compartments from baseline to 15 months. Multiple logistic regression, with adjustments for demographic and clinical variables, was used to assess whether an increased BML score is predictive of the development of knee pain. RESULTS: Among case knees, 54 of 110 (49.1%) showed an increase in BML score within a compartment, whereas only 59 of 220 control knees (26.8%) showed an increase (P < 0.001 by chi-square test). A BML score increase of at least 2 units was much more common in case knees than in control knees (27.5% versus 8.6%; adjusted odds ratio 3.2, 95% confidence interval 1.5-6.8). Among case knees with increased BMLs, most already had BMLs at baseline, with enlarging BMLs at followup, but among the subset of knees with no BMLs at baseline, new BMLs were more common in case knees (11 [32.4%] of 34) than in control knees (9 [10.8%] of 83). CONCLUSION: Development of knee pain is associated with an increase in BMLs as revealed on MRI.     

The bone marrow lesion in osteoarthritis

Osteoarthritis (OA) is considered a multifactorial disease whose development and progression may include several structural abnormalities aside from cartilage destruction. Bone marrow lesions (BMLs) have been reported to be associated with OA pathology, and several studies have advocated its close connection to the severity of joint structural alterations and pain, the main OA clinical manifestation. Hence, BMLs may not only affect subchondral bone and its neuronal and vascular structures but also negatively influence the adjacent tissues. Here, we analyze the pathophysiology and natural history of OA-associated BMLs and their potential relevance to the radiographic progression and severity of the disease. The notion that BMLs may be a precursor to additional articular abnormalities, can be a potential risk factor for development of OA, and may serve as an additional diagnostic tool and a therapeutic target are further discussed.     

Assessing bone loss on radiographs of the knee in osteoarthritis: a cross-sectional study

OBJECTIVE: The only established system to grade subchondral bone attrition in knee osteoarthritis (OA) has low interobserver reliability. In this study, our aim was to convert this system into a reliable tool for the assessment of subchondral bone loss in knee OA. METHODS: Templates that were designed to outline the normal contours of the knee were overlaid onto conventional radiographs of a random sample of 100 knees of OA patients who were awaiting total knee replacement (TKR). Seventy-five films from individuals with chronic knee pain who were not awaiting TKR and 75 films from asymptomatic control subjects were also assessed. Bone loss was graded from 0 (no attrition) to 3 (severe attrition of >10 mm); other established radiologic features were also graded. Spearman's rho was used to determine the correlation of attrition scores with other features, and logistic regression was used to explore whether definite bone attrition was associated with night pain. RESULTS: The inter- and intraobserver reliability values were high for attrition scores and for the presence of definite attrition (score > or =2). Bone attrition was evident in 62% of films from patients awaiting TKR, in 9% of films from individuals with chronic knee pain who were not awaiting TKR, and in 1% of films from controls. In all groups, the correlation between attrition and other features was weak to moderate. There was a nonsignificant association between definite bone attrition and night pain. CONCLUSION: Bone attrition is an additional dimension of knee OA that can be measured reliably. Definite attrition may be associated with night pain.     

Detection of pain-related molecules in the subchondral bone of osteoarthritic knees

Knee pain is predominant among osteoarthritis (OA) patients, but the mechanism is poorly understood. We investigated subchondral bone as a source of OA knee pain using immunohistochemistry. Fifteen medial-type OA knees with minimum involvement of the lateral compartment determined by X-ray as well as magnetic resonance imaging that received total knee arthroplasty (TKA) were involved. Each pair of the medial femoral condyle (MFC) and lateral femoral condyle (LFC) was compared obtained at the time of TKA. Osteocartilaginous MFC and LFC specimens were histologically examined and stained with antibodies against cyclooxygenase 1 (Cox-1), cyclooxygenase 2 (Cox-2), substance P, tumor necrosis factor-alpha (TNF-α), and neuron-specific class III beta-tubulin (TUJ1), a pan-neuronal marker. Formation of cystic lesions was more frequently seen in the MFC. The lesions were composed of vascular endothelial cells, osteoclasts, and mononuclear cells and were present in similar proportions between the MFC and the LFC. Four out of 15 MFC specimens were positive for Cox-1, 15 for Cox-2, and 13 for TNF-α. No LFC specimens were positive for any antibodies. Substance P-positive and TUJ1-positive fibers were found in the subchondral area of the MFC, but not in the LFC. Pathological changes in the subchondral bone can be a source of knee pain, which was detectable by the positive immunoreactivity of substance P, Cox-2, TNF-α, and TUJ1, in the subchondral bone of affected compartments. The relatively immediate reduction in pain obtained by TKA might account for the involvement of the subchondral bone in knee pain because most of the affected subchondral plate is excised in TKA (debridement effect of TKA).     

The association of knee structural pathology with pain at the knee is modified by pain at other sites in those with knee osteoarthritis

The objective of this study was to investigate the associations of knee structural abnormalities with different patterns of pain. A total of 891 participants (average age 63 years; range 50 to 80 years) participated in this study. Presence of pain at the neck, back, hands, shoulders, hips, knees, and feet was assessed by questionnaire. Participants were categorized as having no pain at any site (no pain), pain only at the knee (KP), pain at other sites but not the knee (OP), and pain at the knee and other sites (KOP). T1-weighted or T2-weighted MRI of the right knee was performed to measure cartilage defects, bone marrow lesions (BMLs), and effusion-synovitis. Osteophytes and joint space narrowing were assessed by X-ray. KP, KOP, and OP were, respectively, present in 3, 43, and 42% of the participants. In multivariable analyses, KOP was associated with the presence of cartilage defects, BMLs, and osteophytes (OR 3.57 (95% CI 1.78 to 7.14), 2.37 (1.27 to 4.43), and 2.87 (1.10 to 7.51), respectively) in those with radiographic knee OA. KP was also associated with presence of these structural abnormalities as well as effusion-synovitis, and these associations were much stronger. The associations between structural abnormalities and KOP were weaker than those with KP in those with radiographic knee OA. This suggests that mechanisms mediating the association between structural pathology, localized, and generalized pain may be different, and central sensitization is possibly involved in generalized pain. Pain at other sites needs to be considered in the management and treatment of OA-related pain.     

The relationship of antiresorptive drug use to structural findings and symptoms of knee osteoarthritis

OBJECTIVE: To examine the cross-sectional association between use of medications that have a bone antiresorptive effect (estrogen, raloxifene, and alendronate) and both the structural features of knee osteoarthritis (OA), assessed by magnetic resonance imaging (MRI) and radiography, and the symptoms of knee OA in elderly women. METHODS: Women in the Health, Aging and Body Composition Study underwent MRI and radiography of the knee if they reported symptoms of knee OA, and women without significant knee symptoms were selected as controls. MR images of the knee were assessed for multiple features of OA using the Whole-Organ MRI scoring method, and radiographs were read for Kellgren and Lawrence grade and individual features of OA. Concurrent medication use and knee symptoms were assessed by interview, and knee pain severity was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). RESULTS: There were 818 postmenopausal women from whom we obtained MR images of the knee and data on medication use. Among these women, 214 (26.2%) were receiving antiresorptive drugs. We found no significant association between overall use of antiresorptive drugs and the presence of knee pain and radiographic changes of OA of the knee. Use of alendronate, but not estrogen, was associated with less severity of knee pain as assessed by WOMAC scores. Both alendronate use and estrogen use were associated with significantly less subchondral bone attrition and bone marrow edema-like abnormalities in the knee as assessed by MRI, as compared with women who had not received these medications. CONCLUSION: Elderly women being treated with alendronate and estrogen had a significantly decreased prevalence of knee OA-related subchondral bone lesions compared with those reporting no use of these medications. Alendronate use was also associated with a reduction in knee pain according to the WOMAC scores.     

Bone Microdamage in Acute Knee Injury

Purpose of Review

This review summarizes what is known about how bone tissue responds to microdamage, and how this applies to the subchondral region. This has significant relevance to acute joint injury, and is related to the occurrence of bone marrow lesions (BMLs) which are seen by MRI in 80% of acute knee joint injuries. Here, we review what is known about these phenomena (microcracks and BMLs) in the literature and discuss potential mechanisms by which they may be linked.

Recent Findings

The recent findings in this field have shown that microcracks in bone initiate targeted remodeling via RANKL expression in osteocytes. Other work has shown that subchondral microcracks co-localize with BMLs as viewed by MRI. Finally, BMLs are associated with pain and structural joint degeneration.

Summary

This paper demonstrates that subchondral microcracks likely occur during acute joint injury, and are closely linked to BML that are seem by clinical MRI and thus are potentially involved in the subsequent joint degeneration that occurs after injury.

     

Changes in cartilage and bone metabolism identified by serum markers in early osteoarthritis of the knee joint

Serum concentrations of two extracellular matrix molecules were determined over a 3 yr period in individuals with chronic knee pain to investigate whether sequential serum measurements of cartilage- and bone-derived molecular fragments reflect early stages of osteoarthritis (OA) of the knee joints. Thirty-eight individuals with chronic knee pain (> 3 months at inclusion) with or without radiographic evidence of knee joint OA at the 3 yr follow-up radiographic examination were studied. Serum concentrations of cartilage oligomeric matrix protein (COMP) and bone sialoprotein (BSP) increased significantly (P < 0.001) in the 23 individuals with radiographic OA at follow-up, while remaining unchanged in the 15 individuals with normal radiographs at follow-up. The baseline concentrations of the two variables did not differ between the groups. These findings suggest that pathological processes in cartilage and subchondral bone coincide in OA, and appear to be reflected by circulating levels of macromolecules released from cartilage and bone. Changes in serum levels of COMP and BSP are potential tools in studies of knee joint OA in subjects with chronic knee pain.      

Bone scintigraphy in chronic knee pain: comparison with magnetic resonance imaging

OBJECTIVE: To compare increased bone uptake of 99Tcm-MDP and magnetic resonance (MR) detected subchondral lesions, osteophytes, and cartilage defects in the knee in middle aged people with long-standing knee pain. METHODS: Fifty eight people (aged 41-58 years, mean 50) with chronic knee pain, with or without radiographic knee osteoarthritis, were examined with bone scintigraphy. The pattern and the grade of increased bone uptake was assessed. On the same day, a MR examination on a 1.0 T imager was performed. The presence and the grade of subchondral lesions, osteophytes, and cartilage defects were registered. RESULTS: The kappa values describing the correlation between increased bone uptake and MR detected subchondral lesions varied between 0.79 and 0.49, and between increased bone uptake and MR detected osteophytes or cartilage defects the values were < 0.54. The kappa values describing the correlation between the grade of bone uptake and the grade of the different MR findings was < 0.57. CONCLUSIONS: Good agreement was found between increased bone uptake and MR detected subchondral lesion. The agreement between increased bone uptake and osteophytes or cartilage defects was in general poor as well as the agreement between the grade of bone uptake and the grade of the MR findings.     

Association between patella alta and the prevalence and worsening of structural features of patellofemoral joint osteoarthritis: The multicenter osteoarthritis study

Objective

To examine the relationship between patella alta and the prevalence and worsening at followup of structural features of patellofemoral joint (PFJ) osteoarthritis (OA) on magnetic resonance imaging (MRI).

Methods

The Multicenter Osteoarthritis Study is a cohort study of persons ages 50–79 years with or at risk for knee OA. Patella alta was measured using the Insall‐Salvati ratio (ISR) on the baseline lateral radiograph, and cartilage damage, bone marrow lesions (BMLs), and subchondral bone attrition (SBA) were graded on MRI at baseline and at 30 months of followup in the PFJ. We examined the association of the ISR with the prevalence and worsening of cartilage damage, BMLs, and SBA in the PFJ using logistic regression.

Results

A total of 907 knees were studied (mean age 62 years, body mass index 30 kg/m², ISR 1.10), 63% from female subjects. Compared with knees in the lowest ISR quartile at baseline, those in the highest quartile had 2.4 (95% confidence interval [95% CI] 1.7–3.3), 2.9 (95% CI 2.0–4.3), and 3.5 (95% CI 2.3–5.5) times the odds of having lateral PFJ cartilage damage, BMLs, and SBA, respectively, and 1.5 (95% CI 1.1–2.0), 1.3 (95% CI 0.9–1.8), and 2.2 (95% CI 1.4–3.4) times the odds of having medial PFJ cartilage damage, BMLs, and SBA, respectively. Similarly, those with high ISRs were also at risk for worsening of cartilage damage and BMLs over time than those with low ISRs.

Conclusion

A high ISR, indicative of patella alta, is associated with structural features of OA in the PFJ. Additionally, the same knees have an increased risk of worsening of these same features over time.     

Assessing bone loss on radiographs of the knee in osteoarthritis: A cross‐sectional study

Objective

The only established system to grade subchondral bone attrition in knee osteoarthritis (OA) has low interobserver reliability. In this study, our aim was to convert this system into a reliable tool for the assessment of subchondral bone loss in knee OA.

Methods

Templates that were designed to outline the normal contours of the knee were overlaid onto conventional radiographs of a random sample of 100 knees of OA patients who were awaiting total knee replacement (TKR). Seventy‐five films from individuals with chronic knee pain who were not awaiting TKR and 75 films from asymptomatic control subjects were also assessed. Bone loss was graded from 0 (no attrition) to 3 (severe attrition of >10 mm); other established radiologic features were also graded. Spearman's rho was used to determine the correlation of attrition scores with other features, and logistic regression was used to explore whether definite bone attrition was associated with night pain.

Results

The inter‐ and intraobserver reliability values were high for attrition scores and for the presence of definite attrition (score ≥2). Bone attrition was evident in 62% of films from patients awaiting TKR, in 9% of films from individuals with chronic knee pain who were not awaiting TKR, and in 1% of films from controls. In all groups, the correlation between attrition and other features was weak to moderate. There was a nonsignificant association between definite bone attrition and night pain.

Conclusion

Bone attrition is an additional dimension of knee OA that can be measured reliably. Definite attrition may be associated with night pain.

     

Increase in bone marrow lesions associated with cartilage loss: a longitudinal magnetic resonance imaging study of knee osteoarthritis

OBJECTIVE: Although bone marrow lesions (BMLs) are powerful predictors of joint space loss as visualized on radiographs, the natural history of these lesions, their relationship to cartilage loss, and the association between change in these lesions and cartilage loss are unknown. These questions were tested using longitudinal magnetic resonance imaging (MRI) data in a natural history study of symptomatic knee osteoarthritis (OA). METHODS: MRI of the knee was performed at baseline, 15 months, and 30 months in 217 patients with primary knee OA (122 men, 95 women; mean +/- SD age 66.4 +/- 9.4 years). To assess mechanical alignment, long-limb films were obtained at 15 months. Subchondral bone marrow abnormalities, graded in the medial and lateral tibiofemoral joints, were defined as poorly marginated areas of increased signal intensity in the marrow on fat-suppressed, T2-weighted images. Cartilage morphologic features in the medial and lateral tibiofemoral joints were scored at all time points using a semiquantitative scale. For each of the medial and lateral compartments, generalized estimating equations were used to evaluate the longitudinal relationship of tibiofemoral BMLs to the tibiofemoral cartilage score, with adjustment for malalignment. RESULTS: Fifty-seven percent of knees had BMLs at baseline, of which 99% remained the same or increased in size at followup. Knee compartments with a higher baseline BML score had greater cartilage loss. An increase in BMLs was strongly associated with further worsening of the cartilage score. Enlarging or new BMLs occurred mostly in malaligned limbs, on the side of the malalignment (e.g., new medial BMLs in varus-aligned knees). The association of BML change with medial tibiofemoral cartilage loss was not significant after adjusting for alignment. CONCLUSION: Lesions of the bone marrow are unlikely to resolve and often get larger over time. Compared with BMLs that stay the same, enlarging BMLs are strongly associated with more cartilage loss. Furthermore, any change in BML is mediated by limb alignment.     

A population-based study of the association between hip bone marrow lesions,high cartilage signal,and hip and knee pain

The objective of this study was to describe the cross-sectional and longitudinal relationship between hip bone marrow lesions (BMLs), high cartilage signal, and hip and knee pain. One hundred ninety-eight participants in the Tasmanian Older Adult Cohort Study with right hip MRI conducted at two time points, approx. 2.3 years apart, were included. Short T1 Inversion Recovery MR images were used to quantitatively measure hip BML size and determine high cartilage signal presence. Hip and knee pain were individually assessed using the Western Ontario and McMaster Universities Osteoarthritis index pain score. Fifty-five participants (28 %) had either femoral and/or acetabular BMLs. Cross-sectionally, the presence of large femoral, acetabular, or any hip BMLs was associated with higher odds of hip pain (OR?=?4.42, 95% CI?=?1.37–19.7; OR?=?5.23, 95% CI?=?1.17–22.9; OR?=?4.43, 95% CI?=?1.46–13.2, respectively). High cartilage signal was strongly associated with hip BMLs (OR?=?6.45, 95% CI?=?3.37–12.6), but not with pain. Longitudinally, incident acetabular (Mean diff?=?+5.90, 95% CI?=?+3.78 to +8.15) and femoral BMLs (Mean diff?=?+1.18, 95% CI?=?0.23–1.94) were associated with worsening hip pain, while resolving femoral BMLs were associated with a decrease in knee pain (Mean diff?=??3.18, 95% CI?=??5.99 to ?0.50). The evidence is consistent for hip, but not knee pain, and strongly suggests that large hip BMLs are associated with hip pain. Furthermore, high cartilage signal is asymptomatic, but strongly associated with hip BMLs. These findings suggest that hip BMLs play an important role in hip osteoarthritis.     

Correlates of knee pain in older adults: Tasmanian Older Adult Cohort Study

OBJECTIVE: To describe the association between chondral defects, bone marrow lesions, knee and hip radiographic osteoarthritis (OA), and knee pain. METHODS: Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index. T1- and T2-weighted fat saturation magnetic resonance imaging was performed on the right knee to assess chondral defects and subchondral bone marrow lesions. Radiography was performed on the right knee and hip and scored for radiographic OA. Body mass index (BMI) and knee extension strength were measured. RESULTS: A total of 500 randomly selected men and women participated. The prevalence of knee pain was 48%. In multivariable analysis, prevalent knee pain was significantly associated with medial tibial chondral defects (odds ratio [OR] 2.32, 95% confidence interval [95% CI] 1.02-5.28 for grade 3 versus grade 2 or less; OR 4.93, 95% CI 1.07-22.7 for grade 4 versus grade 2 or less), bone marrow lesions (OR 1.44, 95% CI 1.04-2.00 per compartment), and hip joint space narrowing (OR 1.36, 95% CI 1.07-1.73 per unit), as well as greater BMI and lower knee extension strength. It was not significantly associated with radiographic knee OA. These variables were also associated with more severe knee pain. In addition, there was a dose response association between knee pain and number of sites having grade 3 or 4 chondral defects (OR 1.39, 95% CI 1.12-1.73 per site), with all subjects having knee pain if all compartments of the knee had these defects. CONCLUSION: Knee pain in older adults is independently associated with both full and non-full-thickness medial tibial chondral defects, bone marrow lesions, greater BMI, and lower knee extension strength, but is not associated with radiographic knee OA. The association between radiographic hip OA and knee pain indicates that referred pain from the hip needs to be considered in unexplained knee pain.     

Associations between pain, function, and radiographic features in osteoarthritis of the knee

OBJECTIVE: To assess the associations between pain, loss of function, and radiographic changes in knee osteoarthritis (OA), taking into account both the patellofemoral and tibiofemoral compartments. METHODS: Both knees of 167 community-based patients with OA in at least 1 of their knees were assessed. Pain was measured by visual analog scale, and function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index. Anteroposterior standing radiographs with the knee in extension and lateral 30 degrees flexion were obtained and assessed for the Kellgren/Lawrence score and for individual features (osteophytes, joint space narrowing, and subchondral bone sclerosis) in each compartment. RESULTS: Knees with structural changes in both compartments were more likely to be painful and to be associated with loss of function than were knees in which only 1 compartment was affected. The individual feature most strongly associated with pain was subchondral bone sclerosis. CONCLUSION: Studies exploring the associations between structural and symptomatic knee OA need to include an assessment of the patellofemoral compartment, and individual radiographic features rather than a global severity score should be considered in these studies.     

An OA phenotype may obtain major benefit from bone-acting agents

Background

Osteoarthritis (OA) joints display relevant microstructure alterations associated to an increase in remodeling at subchondral bone, which supports its crucial role in OA pathogenesis. Despite this, the treatment of knee OA patients with antiresorptive drugs has given discordant results, suggesting the existence of a particular patient subset with good response to halting high subchondral remodeling.

Objective

To identify an OA phenotype that may obtain major benefit from therapy with bone-acting agents.

Methods

A systematic review of the literature was performed by searching the Medline and PubMed databases from 1990 to April 2013 using the following keywords: subchondral bone, articular cartilage, and osteoarthritis in various combinations with bone agents, bone mineral density, and scintigraphy.

Results

Early animal and human studies provided the rationale for the beneficial use of bone agents on OA cartilage damage. Several bone-acting agents have reduced low back pain and likely spondylosis progression. Recently, strontium ranelate has been reported to exert both structural and clinical benefits in knee OA patients with radiological progression. However, other antiresorptives have shown divergent results. Human studies suggest that these contradictory results may be due to the lack of well-defined OA phenotypes and an accurate methodology to recruit and follow up these patients.

Conclusions

A particular subset of postmenopausal patients with high remodeling and/or low subchondral bone density may benefit from the treatment with bone-acting agents hindering OA progression. This OA population could be identified with the simultaneous use of subchondral bone dual-energy X-ray absorptiometry and scintigraphy.     

Denuded subchondral bone and knee pain in persons with knee osteoarthritis

Objective

It is unclear how articular cartilage loss contributes to pain in patients with knee osteoarthritis (OA). Full‐thickness cartilage defects expose the subchondral bone plate. The relationship between denuded bone and pain has not been examined. The aim of this study was to investigate whether the percent of denuded bone is associated with moderate‐to‐severe knee pain or frequent knee pain and longitudinally with frequent knee pain 2 years after the baseline evaluation.

Methods

We studied 182 persons with knee OA (305 knees). Applying specialized magnetic resonance imaging techniques, manual segmentation was used to compute cartilage‐covered and denuded bone areas for each surface. Moderate‐to‐severe knee pain was defined as a score of ≥40 mm on a knee‐specific 100‐mm visual analog scale, and frequent knee pain was defined as pain on most days during the past month. Logistic regression and generalized estimating equations were used in analyses, adjusting for age, sex, body mass index, and bone marrow lesions.

Results

Cross‐sectional analyses revealed that moderate‐to‐severe knee pain was associated with percent denuded bone in the medial compartment (adjusted odds ratio [OR] 3.90, 95% confidence interval [95% CI] 1.33–11.47), in the medial and patellar surfaces together, and in the lateral and patellar surfaces. Frequent knee pain was associated with percent denuded bone in the patellar surface (adjusted OR 3.11, 95% CI 1.24–7.81), in the medial and patellar surfaces, and in the lateral and patellar surfaces. Longitudinal analyses (in 168 knees without frequent knee pain at baseline) revealed that percent denuded bone in the medial and patellar surfaces was associated with frequent incident knee pain (adjusted OR 4.19, 95% CI 1.56–11.22).

Conclusion

These results support a relationship between subchondral bone plate exposure and prevalent and incident knee pain in patients with knee OA.

     

Osteoarthritis of the knees in the COPCORD world

This paper examines and summarizes data on knee osteoarthritis (AO) in Community Oriented Program For Control Of Rheumatic Disorders (COPCORD) publications. A literature search was made through PubMed, Google, Proceedings of Asia-Pacific League of Associations for Rheumatology (APLAR) congresses, and Abstracts from APLAR congresses. Data were compiled to examine the prevalence of knee OA and knee pain, sex ratio, urban/rural differences and other risk factors. Data on knee pain and OA were available in a total of 36 COPCORD publications. The pooled prevalence of knee OA was 7.9% in adults above the age of 15 years. It was more common in women. Overweight, squatting and cycling appeared to be modifiable risk factors for knee OA. OA of the knee is the commonest rheumatic disease in studied communities. Further research is needed for identification of its modifiable risk factors and development of strategies for reduction of the community burden of this malady.     

Serum levels of resistin and interleukin-17 are associated with increased cartilage defects and bone marrow lesions in patients with knee osteoarthritis

Objectives: To investigate cross-sectional associations between serum levels of resistin and interleukin-17 (IL-17) and cartilage defects and bone marrow lesions (BMLs) in patients with knee symptomatic osteoarthritis (OA).

Methods: One hundred and ninety-four consecutively-selected patients with knee symptomatic OA (mean 55.4 years, range 34–74, 87% females) were included in Anhui Osteoarthritis (AHOA) Study. Knee cartilage defects and BMLs were determined at different sites using T2-weighted fat-suppressed fast spin echo MRI. Serum resistin, IL-17, and high-sensitivity C-reactive protein (hs-CRP) levels were measured using ELISA.

Results: In multivariable analyses, serum resistin was positively associated with cartilage defects at lateral femoral, lateral tibial, and medial tibial (all p?p?2.45?pg/ml), IL-17 was positively and significantly associated with cartilage defect score at nearly all sites (ORs: 1.33–1.44, all p?p?Conclusions: Serum levels of resistin were positively and independently associated with cartilage defects and BMLs in patients with knee OA. Serum IL-17 was significantly associated with cartilage defects and BMLs in patients with an increased inflammatory status. These suggest that metabolic and inflammatory mechanisms may have a role to play in knee OA.     

Central bone marrow lesions in symptomatic knee osteoarthritis and their relationship to anterior cruciate ligament tears and cartilage loss

OBJECTIVE: Medial and lateral compartment bone marrow lesions (BMLs) have been tied to cartilage loss. We undertook this study to assess 2 types of BMLs in the central region of the knee (type 1 BMLs, which are related anatomically to anterior cruciate ligament [ACL]/posterior cruciate ligament [PCL] insertions, and type 2 BMLs, which encompass both the central region and either the medial or the lateral compartment) and determine their relationship to cartilage loss and ACL tears. METHODS: Magnetic resonance imaging (MRI) of the knee was performed at baseline and at followup (15 and/or 30 months) in 258 subjects with symptomatic osteoarthritis (OA). At baseline, we assessed ACL tears and central BMLs located at or between the tibial spines or adjacent to the femoral notch. Cartilage loss was present if the score in any region of the tibiofemoral joint increased by >or= 1 units at the last available followup, using a modified Whole-Organ MRI Score. We used logistic regression adjusted for alignment, body mass index, Kellgren/Lawrence score, sex, and age. RESULTS: One hundred thirty-nine knees (53.8%) had central BMLs, of which 129 had type 1 BMLs (96 abutted the ACL and had no coexistent type 2 features) and 25 had type 2 BMLs (often overlapped with type 1). Type 1 lesions were associated with ACL tears (odds ratio [OR] 5.9, 95% confidence interval [95% CI] 2.2-16.2) but not with cartilage loss (OR 1.6, 95% CI 0.8-3.1), while medial type 2 BMLs were related to medial cartilage loss (OR 6.1, 95% CI 1.0-35.2). CONCLUSION: Central BMLs that abutted the ACL were highly prevalent and strongly related to ACL pathology, suggesting a role of enthesopathy in OA. Only BMLs with medial extension were related to ipsilateral cartilage loss.