Radiologic assessment of age-related knee joint space changes in women: A 4-year longitudinal study

Artificial Intelligence in osteoarthritis: repair by knee joint distraction shows association of pain, radiographic and immunologic outcomes

OBJECTIVES

Knee joint distraction (KJD) has been associated with clinical and structural improvement and synovial fluid (SF) marker changes. The current objective was to analyze radiographic changes after KJD using an automatic AI-based measurement method, and relate these to clinical outcome and SF markers.

METHODS

20 knee osteoarthritis patients were treated with KJD in regular care. Radiographs and WOMAC were collected before and ∼1-year post-treatment. SF was aspirated before, during, and after treatment; biomarker levels were assessed by immunoassay. Radiographs were analyzed to obtain compartmental minimum and standardized joint space width (JSW), Kellgren-Lawrence (KL) grades, compartmental joint space narrowing (JSN) scores, and osteophytosis and sclerosis scores. Results were analyzed for the most (MAC) and least affected compartment. Radiographic changes were analyzed using Wilcoxon Signed Rank tests for categorical and paired t-test for continuous variables. Linear regression was used to calculate associations between changes in JSW, WOMAC pain, and SF markers.

RESULTS

16 Patients could be evaluated. JSW, KL and JSN improved in around half of the patients, significant only for MAC JSW (p< 0.05). MAC JSW change was positively associated with WOMAC pain change (p< 0.04). Greater MCP-1 and lower TGFβ-1 increases were significantly associated with changes in MAC JSW (p< 0.05). MCP-1 changes were positively associated with WOMAC pain changes (p< 0.05).

CONCLUSION

Automatic radiographic measurements show improved joint structure in most patients after KJD in regular care. MAC JSW increased significantly and was associated with SF biomarker level changes and even with improvements in pain as experienced by these patients.

Do Weight-Bearing Knee Digital Radiographs Help to Track the Severity of OA?

OBJECTIVE

Weight-bearing radiographs are preferred for joint space width (JSW) assessment in OA, sometimes non-weight-bearing radiographs are also done. This study aims to evaluate (1) The knee JSW in weight-bearing (WB) and non-weight-bearing (NWB) X-ray images. (2) Quadriceps angle (Q angle) at weight-bearing and non-weight-bearing positions.

MATERIALS AND METHODS

Patients above 50 years old with symptoms (knee pain, functional limitations, and crepitus) from April 2019 to November 2019 were included in the study. Expert exclude patients with post-surgical evaluation, trauma, and infection. JSW and Q angle measurements with respect to weight-bearing and non-weight-bearing positions were made by the same medical expert to avoid inter-observer variation.

RESULTS

Medial knee JSW varies from 0.49 to 5.75 mm in weight-bearing radiograph and 0.53 mm to 6.16 mm in non-weight-bearing radiograph. Q angle varies from 8.72° to 14.58° in weight-bearing position and 10.13° to 14.92° in non-weight-bearing position. Q angle (< 11.72°) and medial JSW (< 3.725 mm) were found to be significantly associated with the rapid progression of knee varus OA (p < 0.001).

CONCLUSION

NWB digital X-ray images overestimate early and underestimate severe OA. There is a possibility of increasing tibia internal rotation and reduction of joint space width in a standing position (WB) as the phase of knee OA diagnosis. These findings show that weight-bearing knee joint radiographs are helpful to track the progression of knee varus OA and have strong clinical usage than non-weight-bearing radiographs. Patients whose Q angle and knee JSW measures are below the limitations need more attention.

RADIOLOGICAL ASSESSMENT OF KNEE JOINT WIDTH DIFFERENCES IN OLDER ADULTS WITH SYMPTOMATIC MEDIAL KNEE OSTEOARTHRITIS

Knee osteoarthritis (OA) is a degenerative articular disease. The knee joint space width (JSW) is used for grading the severity of knee OA. However, there is a lack of research on differences in the widths of knee joints between both lower limbs in unilateral OA. The purpose of this research was to examine the radiological difference in the affected knee joint and contralateral knee joint by analyzing unilateral older adults with medial knee OA using both knees’ JSW differences. Twenty-five subjects with unilateral medial knee OA participated. X-ray radiographs were used to assess knee JSW, and the paired [Formula: see text]-test was performed to assess the knee joint gap width between the affected side and the unaffected side in the respective medial and lateral sides. The independent [Formula: see text]-test compared the differences between the lateral and medial knee JSWs on the affected side and unaffected side. The paired [Formula: see text]-test did not show a significant difference in the medial and lateral knee JSW on the affected side compared to the unaffected side ([Formula: see text]; 0.11). Meanwhile, the independent [Formula: see text]-test revealed a significant difference between the affected and unaffected sides ([Formula: see text]). This study showed no significant changes in affected knee JSWs compared to unaffected sides, but the difference between the lateral and medial JSWs was significant between the knees affected and unaffected by OA in the older adults with medial knee OA.

Determining individual trajectories of joint space loss: improved statistical methods for monitoring knee osteoarthritis disease progression

OBJECTIVES

Knee osteoarthritis (KOA) progression is frequently monitored by calculating the change in knee joint space width (JSW) measurements. Such differences are small and sensitive to measurement error. We aimed to assess the utility of two alternative statistical modelling methods for monitoring KOA.

MATERIAL AND METHODS

We used JSW on radiographs from both the control arm of the Strontium Ranelate Efficacy in Knee Osteoarthritis trial (SEKOIA), a 3-year multicentre, double-blind, placebo-controlled phase three trial, and the Osteoarthritis Initiative (OAI), an open-access longitudinal dataset from the USA comprising participants followed over 8 years. Individual estimates of annualised change obtained from frequentist linear mixed effect (LME) and Bayesian hierarchical modelling, were compared with annualised crude change, and the association of these parameters with change in WOMAC pain was examined.

RESULTS

Mean annualised JSW changes were comparable for all estimates, a reduction of around 0.14 mm/y in SEKOIA and 0.08 mm/y in OAI. The standard deviation (SD) of change estimates was lower with LME and Bayesian modelling than crude change (SEKOIA SD = 0.12, 0.12 and 0.21 respectively; OAI SD = 0.08, 0.08 and 0.11 respectively). Estimates from LME and Bayesian modelling were statistically significant predictors of change in pain in SEKOIA (LME P-value = 0.04, Bayes P-value = 0.04), while crude change did not predict change in pain (P-value = 0.10).

CONCLUSIONS

Implementation of LME or Bayesian modelling in clinical trials and epidemiological studies, would reduce sample sizes by enabling all study participants to be included in analysis regardless of incomplete follow up, and precision of change estimates would improve. They provide increased power to detect associations with other measures.

The combination of an inflammatory peripheral blood gene expression and imaging biomarkers enhance prediction of radiographic progression in knee osteoarthritis

OBJECTIVE

Predictive biomarkers of progression in knee osteoarthritis are sought to enable clinical trials of structure-modifying drugs. A peripheral blood leukocyte (PBL) inflammatory gene signature, MRI-based bone marrow lesions (BML) and meniscus extrusion scores, meniscal lesions, and osteophytes on X-ray each have been shown separately to predict radiographic joint space narrowing (JSN) in subjects with symptomatic knee osteoarthritis (SKOA). In these studies, we determined whether the combination of the PBL inflammatory gene expression and these imaging findings at baseline enhanced the prognostic value of either alone.

METHODS

PBL inflammatory gene expression (increased mRNA for IL-1β, TNFα, and COX-2), routine radiographs, and 3T knee MRI were assessed in two independent populations with SKOA: an NYU cohort and the Osteoarthritis Initiative (OAI). At baseline and 24 months, subjects underwent standardized fixed-flexion knee radiographs and knee MRI. Medial JSN (mJSN) was determined as the change in medial JSW. Progressors were defined by an mJSN cut-point (≥ 0.5 mm/24 months). Models were evaluated by odds ratios (OR) and area under the receiver operating characteristic curve (AUC).

RESULTS

We validated our prior finding in these two independent (NYU and OAI) cohorts, individually and combined, that an inflammatory PBL inflammatory gene expression predicted radiographic progression of SKOA after adjustment for age, sex, and BMI. Similarly, the presence of baseline BML and meniscal lesions by MRI or semiquantitative osteophyte score on X-ray each predicted radiographic medial JSN at 24 months. The combination of the PBL inflammatory gene expression and medial BML increased the AUC from 0.66 (p = 0.004) to 0.75 (p < 0.0001) and the odds ratio from 6.31 to 19.10 (p < 0.0001) in the combined cohort of 473 subjects. The addition of osteophyte score to BML and PBL inflammatory gene expression further increased the predictive value of any single biomarker. A causal analysis demonstrated that the PBL inflammatory gene expression and BML independently influenced mJSN.

CONCLUSION

The use of the PBL inflammatory gene expression together with imaging biomarkers as combinatorial predictive biomarkers, markedly enhances the identification of radiographic progressors. The identification of the SKOA population at risk for progression will help in the future design of disease-modifying OA drug trials and personalized medicine strategies.

Novel Approach to Estimate Osteoarthritis Progression: Use of the Reliable Change Index in the Evaluation of Joint Space Loss

OBJECTIVE

Osteoarthritis-related changes in joint space measurements over time are small and sensitive to measurement error. The Reliable Change Index (RCI) determines whether the magnitude of change observed in an individual can be attributed to true change. This study aimed to examine the RCI as a novel approach to estimating osteoarthritis progression.

METHODS

Data were from 167 men and 392 women with knee osteoarthritis (diagnosed using the American College of Rheumatology criteria) randomized to the placebo arm of the 3-year Strontium Ranelate Efficacy in Knee Osteoarthritis trial (SEKOIA) and assessed annually. The RCI was used to determine whether the magnitude of change in joint space width (JSW) on radiographs between study years was likely to be true or due to measurement error.

RESULTS

Between consecutive years, 57-69% of participants had an apparent decrease (change <0) in JSW, while 31-43% of participants had annual changes indicating improvement in JSW. The RCI identified JSW decreases in only 6.0% of patients between baseline and year 1, and in 4.5% of patients between the remaining study years. The apparent increases in JSW were almost eliminated between baseline and year 1, and between years 1 and 2 only 1.3% of patients had a significant increase, dropping to 0.9% between years 2 and 3.

CONCLUSION

The RCI provides a method to identify change in JSW, removing many apparent changes that are likely to be due to measurement error. This method appears to be useful for assessing change in JSW from radiographs in clinical and research settings.

Statin use and knee osteoarthritis progression: Results from a post-hoc analysis of the SEKOIA trial

OBJECTIVE

Epidemiological and experimental studies have suggested that lipid disorders might be involved in the pathophysiology of knee osteoarthritis (OA). Studies assessing the effect of statins on knee OA progression have shown conflicting results. We investigated the impact of statin use on radiological progression in patients with radiological and symptomatic knee OA.

METHODS

In total, 336 patients from the placebo arm of SEKOIA trial completed the 3-year follow-up and were included in this post-hoc analysis. Statin use was recorded at baseline interview. Minimal medial tibiofemoral joint space was measured on plain radiographs by an automated method at baseline and then annually. Radiologic progression was defined as joint space narrowing≥0.5mm over 3 years.

RESULTS

Overall, 71 patients were statin users (21.1%). They had a higher BMI (31.1±5.3 vs. 29.3±5.2kg/m², P=0.008), a higher sum of metabolic factors (≥3 factors: 43.7% vs 7.2%; P for trend<0.001) and a higher rate of radiological progression (49.3% vs. 32.1%, P=0.007) as compared to statin non-users. The significant association between radiological progression and statin use was independent of age, gender, WOMAC global score, disease duration, baseline joint space width, hypertension, type 2 diabetes, obesity (BMI>30kg/m²) and cardiovascular diseases [relative risk 1.49 (95% CI: 1.10-2.02), P=0.010].

CONCLUSION

Among patients with knee OA, statin use was associated with radiological worsening over 3 years, regardless of other potential confounding factors (obesity, type 2 diabetes, hypertension, disease duration, symptom intensity and radiological severity).

Prediction of cartilaginous tissue repair after knee joint distraction

BACKGROUND

For young patients (<65years), knee joint distraction (KJD) may be a joint-saving treatment option for end-stage knee osteoarthritis. Distracting the femur from the tibia by five millimeters for six to eight weeks using an external fixation frame results in cartilaginous tissue repair, in addition to clinical benefits. This study is a first attempt to predict the degree of cartilaginous tissue repair after KJD.

METHODS

Fifty-seven consecutive patients received KJD. At baseline and at one year of follow-up, mean and minimum joint space width (JSW) of the most-affected compartment was determined on standardized radiographs. To evaluate the predictive ability of baseline characteristics for JSW at one year of follow-up, multivariable linear regression analysis was performed.

RESULTS

Mean JSW±SD of the most affected compartment increased by 0.95±1.23mm to 3.08±1.43mm at one year (P<0.001). The minimum JSW increased by 0.94±1.03mm to 1.63±1.21mm at one year of follow-up (P<0.001). For a larger mean JSW one year after KJD, only Kellgren & Lawrence grade (KLG) at baseline was predictive (Regression coefficient (β)=0.47, 95% CI=0.18 to 0.77, P=0.002). For a larger minimum JSW, KLG (β=0.46, 95% CI=0.19 to 0.73, P=0.001) and male gender (β=0.52, 95% CI=0.06 to 0.99, P=0.028) were statistically predictive. Eight weeks of distraction time neared significance (β=0.44, 95% CI=-0.05 to 0.93, P=0.080).

CONCLUSIONS

In our cohort of patients treated with KJD, males with higher KLG had the best chance of cartilaginous tissue repair by distraction.

Changes in Knee Osteoarthritis, Symptoms, and Function After Anterior Cruciate Ligament Reconstruction: A 20-Year Prospective Follow-up Study

BACKGROUND

Progression of tibiofemoral (TF) and patellofemoral (PF) osteoarthritis (OA) and changes in knee function more than 15 years after anterior cruciate ligament reconstruction (ACLR) are not well understood.

PURPOSE

To examine the progression of knee OA and changes in symptoms and function in isolated and combined injuries from 15 to 20 years after ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 210 subjects with ACLR were prospectively followed. At the 15- and 20-year follow-ups, radiographs were obtained and classified by the Kellgren and Lawrence (K-L) grading system. Symptoms and function were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS) as well as isokinetic quadriceps and hamstring muscle strength tests.

RESULTS

There were 168 subjects (80%) who returned for the 20-year follow-up, with a mean (±SD) age of 45 ± 9 years, mean body mass index of 27 ± 4, and median Tegner activity level of 4 (range, 0-9). The prevalence of radiographic TF and PF OA at the 20-year follow-up was 42% and 21%, respectively. Patients with ACL injuries and other combined injuries had significantly higher prevalence of radiographic TF OA compared with those who had isolated ACL injury (P < .0001). There was a 13% increase in radiographic TF OA (P = .001) and an 8% increase in PF OA (P = .015) from the 15- to the 20-year follow-up. A significant deterioration in knee symptoms and function was observed on the KOOS subscales (P ≤ .01), with the exception of quality of life (P = .14), as well as a decrease in quadriceps muscle strength and hamstring muscle strength (P < .0001).

CONCLUSION

The prevalence of radiographic TF and PF OA was 42% and 21%, respectively. A significantly higher prevalence of TF OA was found for subjects with combined injuries compared with those who had isolated ACL injury. The majority of the subjects were stable radiographically over the 5 years between follow-ups. A statistically significant deterioration in symptoms and function was noted, but the mean changes were of questionable clinical importance.

High Kellgren-Lawrence Grade and Bone Marrow Lesions Predict Worsening Rates of Radiographic Joint Space Narrowing; The SEKOIA Study

OBJECTIVE

Determinants of radiographic progression in osteoarthritis (OA) are poorly understood. We investigated which features on baseline magnetic resonance imaging (MRI) acted as predictors of change in joint space width (JSW).

METHODS

A total of 559 men and women over the age of 50 years with clinical knee OA [Kellgren-Lawrence (KL) grade 2-3] were recruited to the placebo arm of the SEKOIA study (98 centers; 18 countries). Minimal tibiofemoral joint space and KL grade on plain radiograph of the knee were assessed at baseline and at yearly followup up to 3 years. In a subset, serial knee MRI examinations were performed. Individuals with a bone marrow lesion (BML) ≥ grade 2 at the tibiofemoral joint at baseline were classified as BML-positive. Relationships between change in JSW and risk factors were assessed using linear regression.

RESULTS

The mean age of study participants was 62.8 (SD 7.5) years and 73% were female; 38.6% had BML. Mean baseline JSW was 3.65 mm. This reduced by 0.18 (0.30) mm/year in men and 0.13 (0.23) mm/year in women. Those with BML had a significantly higher rate of annualized change in JSW; this relationship remained robust after adjustment for age, sex, and baseline KL grade [β = -0.10 (95% CI -0.18, -0.02) mm/yr]. Age, sex, baseline KL grade, and other MRI findings did not influence the rate of change in JSW.

CONCLUSION

The rate of change in JSW was similar in men and women. BML on knee MRI predicted the rate of radiographic change in JSW. This relationship was independent of age, sex, and baseline KL grade.

Defining the presence of radiographic knee osteoarthritis: a comparison between the Kellgren and Lawrence system and OARSI atlas criteria

PURPOSE

The Kellgren and Lawrence (K/L) system and Osteoarthritis Research Society International (OARSI) atlas are frequently used to define radiographic knee osteoarthritis (OA). The purpose of the current study was to determine the extent to which tibiofemoral OA rates differ between the K/L system and OARSI atlas criteria and to compare qualitative (K/L and OARSI) and quantitative (millimetres) measures of joint space narrowing (JSN).

METHODS

Posteroanterior radiographs of 1,178 knees, from 621 individuals with varying severity of OA, were graded by a trained physician with the K/L system (grade 0-4) and the OARSI atlas (osteophytes/JSN graded 0-3). Using the K/L system, the presence of OA was defined with the traditional cut-off of ≥grade 2 (definite osteophyte and possible JSN) and an alternative cut-off of at least a definite osteophyte alone (≥grade 2/osteophyte). For the OARSI atlas, OA was considered present if the sum of osteophytes or JSN ≥grade 2, or grade 1 JSN occurred in combination with grade 1 osteophyte. Minimum joint space width (mJSW) was measured manually in millimetres.

RESULTS

According to the K/L system (≥grade 2), 167 knees (14.2 %) had tibiofemoral OA and 203 (17.3 %) had ≥grade 2/osteophyte. In contrast, 309 knees (26.2 %) had tibiofemoral OA according to OARSI atlas criteria. K/L and OARSI JSN descriptions were significantly associated with mJSW (p < 0.022).

CONCLUSIONS

Radiographic tibiofemoral OA was almost twice as common using OARSI atlas criteria compared with the K/L system. This discrepancy is likely to contribute to the large variability of OA prevalence observed in the literature and is important for clinicians to consider when diagnosing radiographic OA. The cut-off for defining radiographic knee OA using the two systems should not be considered comparable.

LEVEL OF EVIDENCE

III.

Diabetes is a risk factor for knee osteoarthritis progression

PURPOSE

Recent studies have suggested that metabolic factors (obesity, diabetes, hypertension and dyslipidemia) and their clustering in metabolic syndrome (MetS) might be involved in the pathophysiology of knee osteoarthritis (OA). We investigated their impact on radiographic progression by an annualised measure of the joint space narrowing (JSN) of the medial tibiofemoral compartment.

METHODS

559 patients older than 50 years with symptomatic knee OA were recruited for the placebo arm of the SEKOIA trial. The presence of diabetes, hypertension and dyslipidemia was determined at baseline interview. Body mass index (BMI) was calculated, obesity was considered >30 kg/m(2). MetS was defined by the sum of metabolic factors ≥ 3. Minimal medial tibiofemoral joint space on plain radiographs was measured by an automated method at baseline and then annually for up to 3 years.

RESULTS

The mean age of patients was 62.8 [62.2-63.4] years; 392 were women. A total of 43.8% was obese, 6.6% had type 2 diabetes, 45.1% hypertension, 27.6% dyslipidemia and 13.6% MetS. Mean annualised JSN was greater for patients with type 2 diabetes than without diabetes (0.26 [-0.35 to -0.17] vs 0.14 [-0.16 to -0.12] mm; P = 0.001). This association remained significant after adjustment for sex, age, BMI, hypertension and dyslipidemia (P = 0.018). In subgroup analysis, type 2 diabetes was a significant predictor of JSN in males but not females. The other metabolic factors and MetS were not associated with annualised JSN.

CONCLUSION

Type 2 diabetes was a predictor of joint space reduction in men with established knee OA. No relationships were found between MetS or other metabolic factors and radiographic progression.

History of knee injury and MRI-assessed knee structures in middle- and older-aged adults: a cross-sectional study

The aim of this cross-sectional study was to describe the associations between history of knee injury and knee structure using magnetic resonance imaging (MRI). This study included two population-based samples: the Tasmanian Older Adult Cohort (TASOAC) study (n = 430; mean age, 63.0 years; range, 51-79 years; 51 % female) and the Offspring study (n = 372; mean age, 45.0 years; range, 26-61 years; 57.5 % female). In both studies, 1.5 T MRI scans of the right knee were performed to measure bone marrow lesions (BMLs), cartilage volume, tibial bone area, cartilage defects and meniscal pathology. History of knee injury was assessed using a self-administered questionnaire. The association between knee injury and knee structure was determined using multiple linear and log binomial regression models. Nineteen percent of the middle-aged and 12 % of the older adults reported a history of knee injury. In middle-aged adults, BML presence (prevalence ratio (PR) = 1.6 (95 % CI, 1.2; 2.1)), tibial bone area (difference of means (DM) = +86 (+23, +149)) and meniscal extrusion presence (PR = 2.7 (1.1, 6.8)) were significantly higher in those with knee injury. In older adults, cartilage defect presence (PR = 1.3 (1.0, 1.7)), lateral (DM = -265 (-439, -92)) and total tibial (DM = -325 (-600, -51)) cartilage volume, BML presence (PR = 1.4 (1.0, 1.9)) and tibial bone area (DM = +140 (+19, +260)) were significantly associated with knee injury. Meniscal tears showed no significant associations in either cohorts. The association between knee injury and MRI-assessed structural pathology in the knee joint is moderate and appears to be stronger in older adults compared to middle-aged adults.

Strontium ranelate in the treatment of knee osteoarthritis: new insights and emerging clinical evidence

Osteoarthritis is a primary cause of disability and functional incapacity. Pharmacological treatment is currently limited to symptomatic management, and in advanced stages, surgery remains the only solution. The therapeutic armamentarium for osteoarthritis remains poor in treatments with an effect on joint structure, that is, disease-modifying osteoarthritis drugs (DMOADs). Glucosamine sulfate and chondroitin sulfate are the only medications for which some conclusive evidence for a disease-modifying effect is available. Strontium ranelate is currently indicated for the prevention of fracture in severe osteoporosis. Its efficacy and safety as a DMOAD in knee osteoarthritis has recently been explored in the SEKOIA trial, a 3-year randomized, double-blind, placebo-controlled trial. Outpatients with knee osteoarthritis, Kellgren and Lawrence grade 2 or 3, and joint space width (JSW) of 2.5-5 mm received strontium ranelate 1 g/day (n = 558) or 2 g/day (n = 566), or placebo (n = 559). This sizable population was aged 62.9 years and had a JSW of 3.50 ± 0.84 mm. Treatment with strontium ranelate led to significantly less progression of knee osteoarthritis: estimates for annual difference in joint space narrowing versus placebo were 0.14 mm [95% confidence interval (CI) 0.05-0.23 mm; p < 0.001] for 1 g/day and 0.10 mm (95% CI 0.02-0.19 mm; p = 0.018) for 2 g/day, with no difference between strontium ranelate groups. Radiological progression was less frequent with strontium ranelate (22% with 1 g/day and 26% with 2 g/day versus 33% with placebo, both p < 0.05), as was radioclinical progression (8% and 7% versus 12%, both p < 0.05). Symptoms also improved with strontium ranelate 2 g/day only in terms of total WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score (p = 0.045), and its components for pain (p = 0.028) and physical function (p = 0.099). Responder analyses using a range of criteria for symptoms indicated that the effect of strontium ranelate 2 g/day on pain and physical function was clinically meaningful. Strontium ranelate was well tolerated. The observation of both structure and symptom modification with strontium ranelate 2 g/day makes SEKOIA a milestone in osteoarthritis research and treatment.

[Quantitative analysis for narrowing of radiographic joint space in knee osteoarthritis]

Conventional radiography is first performed in the evaluation of knee osteoarthritis (OA). In view of diagnostic accuracy and reproducibility, joint space narrowing that is a typical feature of knee OA should be evaluated quantitatively based on the image findings, because it has been evaluating subjectively. We measured joint space widths and joint space areas on knee radiographs to analyze joint space narrowing quantitatively and investigated the usefulness in classification of the severity of knee OA. Radiographs of 35 no OA knees (normal group) and 46 OA knees (OA group) were analyzed in this study. Medial and lateral joint space width and joint space area were measured manually using ImageJ i.e., a public domain image processing program. Measured values were corrected for the physical size with the length of epicondylar line, and statistically significant differences between the normal group and OA group were investigated. The results showed that medial joint space width was significantly smaller and lateral joint space width was significantly larger in the OA group than in the normal group. Furthermore, joint space area in the OA group decreased significantly compared that in normal group. We conclude that joint space widths and joint space area are important parameters to classify the severity of knee OA.

Efficacy and safety of strontium ranelate in the treatment of knee osteoarthritis: results of a double-blind, randomised placebo-controlled trial

Background

Strontium ranelate is currently used for osteoporosis. The international, double-blind, randomised, placebo-controlled Strontium ranelate Efficacy in Knee OsteoarthrItis triAl evaluated its effect on radiological progression of knee osteoarthritis.

Methods

Patients with knee osteoarthritis (Kellgren and Lawrence grade 2 or 3, and joint space width (JSW) 2.5–5 mm) were randomly allocated to strontium ranelate 1 g/day (n=558), 2 g/day (n=566) or placebo (n=559). The primary endpoint was radiographical change in JSW (medial tibiofemoral compartment) over 3 years versus placebo. Secondary endpoints included radiological progression, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and knee pain. The trial is registered (ISRCTN41323372).

Results

The intention-to-treat population included 1371 patients. Treatment with strontium ranelate was associated with smaller degradations in JSW than placebo (1 g/day: −0.23 (SD 0.56) mm; 2 g/day: −0.27 (SD 0.63) mm; placebo: −0.37 (SD 0.59) mm); treatment-placebo differences were 0.14 (SE 0.04), 95% CI 0.05 to 0.23, p<0.001 for 1 g/day and 0.10 (SE 0.04), 95% CI 0.02 to 0.19, p=0.018 for 2 g/day. Fewer radiological progressors were observed with strontium ranelate (p<0.001 and p=0.012 for 1 and 2 g/day). There were greater reductions in total WOMAC score (p=0.045), pain subscore (p=0.028), physical function subscore (p=0.099) and knee pain (p=0.065) with strontium ranelate 2 g/day. Strontium ranelate was well tolerated.

Conclusions

Treatment with strontium ranelate 1 and 2 g/day is associated with a significant effect on structure in patients with knee osteoarthritis, and a beneficial effect on symptoms for strontium ranelate 2 g/day.

Efficacy and safety of oral strontium ranelate for the treatment of knee osteoarthritis: rationale and design of randomised, double-blind, placebo-controlled trial

OBJECTIVE

The osteoporosis drug strontium ranelate dissociates bone remodelling processes. It also inhibits subchondral bone resorption and stimulates cartilage matrix formation in vitro. Exploratory studies in the osteoporosis trials report that strontium ranelate reduces biomarkers of cartilage degradation, and attenuates the progression and clinical symptoms of spinal osteoarthritis, suggesting symptom- and structure-modifying activity in osteoarthritis. We describe the rationale and design of a randomised trial evaluating the efficacy and safety of strontium ranelate in knee osteoarthritis.

RESEARCH DESIGN, METHODS, AND RESULTS

This double-blind, placebo-controlled trial (98 centres, 18 countries) includes ambulatory Caucasian men and women aged ≥50 years with primary knee osteoarthritis of the medial tibiofemoral compartment (Kellgren and Lawrence grade 2 or 3), joint space width (JSW) 2.5 to 5 mm, and knee pain on most days in the previous month (intensity ≥40 mm on a visual analogue scale). Patients are randomly allocated to three groups (strontium ranelate 1 or 2 g/day, or placebo). Follow-up is expected to last 3 years. The primary endpoint is radiographic change in JSW from baseline in each group versus placebo. The main clinical secondary endpoint is WOMAC score at the knee. Safety is assessed at every visit. It is estimated that 1600 patients are required to establish statistical significance with power >90% (0.2 mm ± 10% between-group difference in change in JSW over 3 years). Recruitment started in April 2006. The results are expected in spring 2012.

CLINICAL TRIAL REGISTRATION

The trial is registered on www.controlled-trials.com (number ISRCTN41323372).

CONCLUSIONS

This randomised, double blind, placebo-controlled study will establish the potential of strontium ranelate in improving structure and symptoms in patients with knee osteoarthritis.

Responsiveness to change and reliability of measurement of radiographic joint space width in osteoarthritis of the knee: a systematic review

OBJECTIVE

The goal of this systematic review was to report the responsiveness to change and reliability of conventional radiographic joint space width (JSW) measurement.

METHOD

We searched the PubMed and Embase databases using the following search criteria: [osteoarthritis (OA) (MeSH)] AND (knee) AND (X-ray OR radiography OR diagnostic imaging OR radiology OR disease progression) AND (joint space OR JSW or disease progression). We assessed responsiveness by calculating the standardized response mean (SRM). We assessed reliability using intra- and inter-reader intra-class correlation (ICC) and coefficient of variation (CV). Random-effects models were used to pool results from multiple studies. Results were stratified by study duration, design, techniques of obtaining radiographs, and measurement method.

RESULTS

We identified 998 articles using the search terms. Of these, 32 articles (43 estimates) reported data on responsiveness of JSW measurement and 24 (50 estimates) articles reported data on measures of reliability. The overall pooled SRM was 0.33 [95% confidence interval (CI): 0.26, 0.41]. Responsiveness of change in JSW measurement was improved substantially in studies of greater than 2 years duration (0.57). Further stratifying this result in studies of greater than 2 years duration, radiographs obtained with the knee in a flexed position yielded an SRM of 0.71. Pooled intra-reader ICC was estimated at 0.97 (95% CI: 0.92, 1.00) and the intra-reader CV estimated at 3.0 (95% CI: 2.0, 4.0). Pooled inter-reader ICC was estimated at 0.93 (95% CI: 0.86, 0.99) and the inter-reader CV estimated at 3.4% (95% CI: 1.3%, 5.5%).

CONCLUSIONS

Measurement of JSW obtained from radiographs in persons with knee is reliable. These data will be useful to clinicians who are planning RCTs where the change in minimum JSW is the outcome of interest.

Normal and threshold values of radiographic parameters for knee osteoarthritis using a computer-assisted measuring system (KOACAD): the ROAD study

BACKGROUND

Although radiographic severity of the knee is commonly determined by the Kellgren-Lawrence (KL) grading scale, it does not separately assess joint space narrowing or osteophyte formation. The present study aimed to establish normal and threshold values of radiographic parameters for knee osteoarthritis (OA) using the knee osteoarthritis computer-aided diagnosis (KOACAD) measuring system on a large-scale population-based cohort of the Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) population.

METHODS

From a total of 3040 participants in the ROAD study, standing anteroposterior radiographs of the knee were obtained from 2975 subjects (1041 men, 1934 women) in the ROAD cohort, and 5950 knees were evaluated using the KOACAD system to obtain the medial and lateral minimum joint space width (mJSW), medial and lateral joint space area (JSA), osteophyte area (OPA), and femorotibial angle (FTA). These indices were compared with the KL scores, and cutoff values for radiographic knee OA were determined by receiver operating characteristic (ROC) curve analysis.

RESULTS

The mean KOACAD parameters for KL = 0 were as follows: medial mJSW 3.70 mm; lateral mJSW 4.77 mm, medial JSA 125.0 mm(2), lateral JSA 140.0 mm(2), OPA 0, and FTA 176.1° in men; for women they were medial mJSW 3.26 mm, lateral mJSW 4.22 mm, medial JSA 100.9 mm(2), lateral JSA 111.0 mm(2), OPA 0, and FTA 174.9°. Threshold values for KL ≥ 2 provided by ROC curve analysis with area under the curve (AUC) > 0.7 were medial mJSW 2.8 mm and medial JSA 107.3 mm(2) in men and medial mJSW 2.7 mm in women. Those for KL ≥ 3 were medial mJSW 2.1 mm, medial JSA 81.1 mm(2), OPA 2.4 mm(2), and FTA 179.6° in men; and medial mJSW 2.1 mm, medial JSA 66.6 mm(2), OPA 2.5 mm(2), and FTA 178.1° in women. We then determined the cutoff values for medial knee OA and lateral knee OA.

CONCLUSIONS

The present study established normal and threshold values of parameters for knee OA using an automated computer-assisted program on plain radiographs.

Relationship between knee and ankle degeneration in a population of organ donors

BACKGROUND

Osteoarthritis (OA) is a progressive degenerative condition of synovial joints in response to both internal and external factors. The relationship of OA in one joint of an extremity to another joint within the same extremity, or between extremities, has been a topic of interest in reference to the etiology and/or progression of the disease.

METHODS

The prevalence of articular cartilage lesions and osteophytes, characteristic of OA, was evaluated through visual inspection and grading in 1060 adult knee/tali pairs from 545 cadaveric joint donors.

RESULTS

Joint degeneration increased more rapidly with age for the knee joint, and significantly more knee joints displayed more severe degeneration than ankle joints from as early as the third decade. Women displayed more severe knee degeneration than did men. Severe ankle degeneration did not exist in the absence of severe knee degeneration. The effect of weight on joint degeneration was joint-specific whereby weight had a significantly greater effect on the knee. Ankle grades increasingly did not match within a donor as the grade of degeneration in either the left or the right knee increased.

CONCLUSIONS

Gender and body type have a greater effect on knee joint integrity as compared to the ankle, suggesting that knees are more prone to internal causative effects of degeneration. We hypothesize that the greater variability in joint health between joints within an individual as disease progresses from normal to early signs of degeneration may be a result of mismatched limb kinetics, which in turn might lead to joint disease progression.

Clinical predictors of elective total joint replacement in persons with end-stage knee osteoarthritis

Background

Arthritis is a leading cause of disability in the United States. Total knee arthroplasty (TKA) has become the gold standard to manage the pain and disability associated with knee osteoarthritis (OA). Although more than 400 000 primary TKA surgeries are performed each year in the United States, not all individuals with knee OA elect to undergo the procedure. No clear consensus exists on criteria to determine who should undergo TKA. The purpose of this study was to determine which clinical factors will predict the decision to undergo TKA in individuals with end-stage knee OA. Knowledge of these factors will aid in clinical decision making for the timing of TKA.

Methods

Functional data from one hundred twenty persons with end-stage knee OA were obtained through a database. All of the individuals complained of knee pain during daily activities and had radiographic evidence of OA. Functional and clinical tests, collectively referred to as the Delaware Osteoarthritis Profile, were completed by a physical therapist. This profile consisted of measuring height, weight, quadriceps strength and active knee range of motion, while functional mobility was assessed using the Timed Up and Go (TUG) test and the Stair Climbing Task (SCT). Self-perceived functional ability was measured using the activities of daily living subscale of the Knee Outcome Survey (KOS-ADLS). A logistic regression model was used to identify variables predictive of TKA use.

Results

Forty subjects (33%) underwent TKA within two years of evaluation. These subjects were significantly older and had significantly slower TUG and SCT times (p < 0.05). Persons that underwent TKA were also significantly weaker, had lower self-reported function and had less knee extension than persons who did not undergo TKA. No differences between groups were seen for BMI, gender, knee flexion ROM and unilateral versus bilateral joint disease. Using backward regression, age, knee extension ROM and KOS-ADLS together significantly predicted whether or not a person would undergo TKA (p ≤ 0.001, R² = 0.403).

Conclusions

Younger patients with full knee ROM who have a higher self-perception of function are less likely to undergo TKA. Physicians and clinicians should be aware that potentially modifiable factors, such as knee ROM can be addressed to potentially postpone the need for TKA.