Minimum Joint Space Width Research Articles

Initial tissue repair predicts long-term clinical success of knee joint distraction as treatment for knee osteoarthritis

Knee joint distraction (KJD), a joint-preserving surgery for severe osteoarthritis (OA), provides clinical and structural improvement and postpones the need for total knee arthroplasty (TKA). This study evaluates 9-year treatment outcome and identifies characteristics predicting long-term treatment success. Patients with severe tibiofemoral OA (n=20; age<60 years) indicated for TKA were treated with KJD. Questionnaires, radiographs, and magnetic resonance imaging (MRI) were used for evaluation. Survival after treatment was analyzed, where 'failure' was defined by TKA over time. 9-year survival was 48%, and 72% for men (compared to 14% for women; P=0.035) and 73% for those with a first-year minimum joint space width (JSW) increase of >0.5mm (compared to 0% for <0.05mm; P=0.002). Survivors still reported clinical improvement compared to baseline (ΔWOMAC+29.9 points (95%CI 16.9-42.9; P=0.001), ΔVAS-46.8mm (-31.6-61.9; P<0.001)). Surprisingly, patients getting TKA years after KJD still reported clinical improvement although less pronounced (ΔWOMAC+20.5 points (-1.8-42.8; P=0.067), ΔVAS-25.4mm (-3.2-47.7; P=0.030)). Survivors showed long-lasting minimum JSW increase (baseline 0.3mm (IQR 1.9), follow-up 1.3mm (2.5); P=0.017) while 'failures' did not (baseline 0.4mm (1.8), follow-up 0.2mm (1.5); P=0.161). First-year minimum JSW on radiographs and cartilage thickness increase on MRI predict 9-year survival (HR 0.05 and 0.12, respectively; both P<0.026). Male gender was associated with survival (HR 0.24; P=0.050). KJD shows long-lasting clinical and structural improvement. In addition to a greater survival rate for males (>two out of three), the initial cartilage repair activity appears to be important for long-term clinical success.

Clinical and radiologic results after open-wedge high tibial osteotomy in haemophilic knee arthropathy with varus deformity.

The previous studies have described only closed-wedge high tibial osteotomy (HTO) in haemophilic arthropathy (HA). The purpose of this study was to evaluate clinical and radiographic results after open-wedge HTO in HA with varus knee deformity. We included 13 open-wedge HTOs in HA performed between 2005 and 2016. The mean age of patients was 28.9years. Visual analogue scale (VAS), Western Ontario and McMaster Universities (WOMAC), and range of motion (ROM) indices were assessed. Any complications or requirements for total knee arthroplasty (TKA) were investigated. Mechanical axis (MA), minimal joint space width (mJSW) and Pettersson score were measured. Bone union rates at 3 and 6months postoperative were evaluated. VAS improved from 5.1 to 2.4 (P<.001). WOMAC was 66.5 preoperatively, and 26.6 postoperatively (P<.001). Pre- and postoperative ROM did not differ significantly. There were no cases of HTO converted to TKA, but one case of HTO required TKA 152months postoperative. No complications were observed. The MA was corrected from varus 5.1° to valgus 1.2° (P<.001). Pre- and postoperative mJSW did not significantly differ. Pettersson score improved from 3.84 to 2.47 (P<.001). The bone union rates at the osteotomy gap were 45.2% and 67.8% at 3 and 6months postoperative. Open-wedge HTO should be considered in cases of HA with varus deformity in young haemophilic patients, even though inflammatory arthritis is not an optimal indication for this procedure. It can be an appropriate treatment with respect to the choice to postpone TKA.

The role of thigh muscle and adipose tissue in knee osteoarthritis progression in women: data from the Osteoarthritis Initiative

To determine whether loss in thigh muscle strength in women concurrent with knee osteoarthritis progression is associated with reductions of muscle anatomical cross-sectional area (ACSA) or specific-strength (i.e., isometric force÷ACSA), and to explore relationships with local adiposity. Female participants from the Osteoarthritis Initiative with Kellgren-Lawrence grade ≤3, thigh isometric strength measurements, and thigh magnetic resonance images at year-two (Y2) and year-four (Y4) (n=739, age 62±9 years; body mass index measurements (BMI) 28.8±5.9kg/m2) were grouped into: (1) those with vs without symptomatic progression (≥9 increase in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-pain [scale: 0-100]); and (2) those with vs without radiographic progression (≥0.7mm reduction in minimum joint space width). The change in knee extensor and flexor ACSA and specific-strength, and subcutaneous and intermuscular fat (IMF) ACSAs were compared between progressors and non-progressors using analysis of covariance. Symptomatic progression was associated with a significantly greater loss (p<0.001) of knee extensor ACSA (-2.0%, 95%CI -2.5,-1.5) compared to those without progression (-0.7%, 95%CI -1.0,-0.4), and greater loss (p=0.020) of knee flexor specific-strength (-7.6%, 95%CI -11.5,-3.7; vs-2.4%, 95%CI -4.8, 0.0). Radiographic progression was associated with a significantly greater increase (p=0.023) in IMF (+1.7%, 95%CI -0.1,+3.6) compared to those without progression (-0.6%, 95%CI -1.6,+0.3). The significant reduction in thigh muscle strength concurrent with symptomatic progression in women appears to be associated with loss of extensor muscle ACSA and flexor specific-strength. In contrast, radiographic progression appears to be unrelated to muscle properties, but to be associated with local (intermuscular) adiposity gains.

Long-term benefit and survival of knee joint distraction as treatment of severe knee osteoarthritis

Purpose: In relatively young patients with end-stage knee osteoarthritis (OA), total knee arthroplasty (TKA) comes with the risk of future revision surgery. Knee joint distraction (KJD) is joint preserving surgery, which has been shown to provide clinical and structural improvement for at least five years. The aim of this study was to evaluate long-term clinical and structural results and identify characteristics predicting survival of the native knee joint. Methods: Patients (n = 20; age <60 years) with end-stage tibiofemoral OA indicated for TKA were treated with KJD. WOMAC questionnaires (100 being best) and VAS pain scores (0 being best) were used for clinical evaluation before treatment (baseline) and every year after treatment, up to nine years. The minimum and mean joint space width (JSW) were measured using KIDA software on standardized radiographs to evaluate structural changes at baseline and one, two, five and seven years after treatment. Survival after treatment was analyzed using the Kaplan-Meier estimator, where failure was defined by TKA. Paired t-tests were used to evaluate clinical and structural changes compared to baseline for survivors and non-survivors. Nine-year survival of KJD was predicted using logistic regression analyses. Results: Three patients withdrew consent during follow-up. Nine years after treatment, survival was 48% and survivors reported clinical improvement compared to baseline: ΔWOMAC +29.9 points (95%CI +16.9 to +42.9; P = 0.001; Fig. 1A), ΔVAS -46.8 mm (95%CI −31.6 to −61.9; P<0.001). Survivors showed a significant remained increase of the minimum JSW (+0.62 mm; 95%CI +0.13 to +1.11; P = 0.020; Fig. 1B) and non-significant increase in mean JSW (+0.31; 95%CI −0.91 to +1.55; P = 0.562) after seven years. In patients whose treatment failed, last reported clinical scores were still improved compared to baseline: ΔWOMAC +20.5 points (95%CI −1.8 to +42.8; P = 0.067; Fig. 1A), ΔVAS −25.4 mm (95%CI −3.2 to −47.7; P = 0.030). At last measurement, the minimum JSW was still significantly increased (+0.37; 95%CI +0.02 to +0.73; P = 0.042; Fig. 1B) while the mean JSW was similar compared to baseline (−0.06; 95%CI −0.85 to +0.72; P = 0.854). Survival analysis showed a difference in survival percentage nine years after treatment for gender (women 14%, men 70%; P = 0.035; Fig. 2A) and for amount of increase in minimum JSW in the first year after treatment (<0.5 mm increase 0%, >0.5 mm increase 72%; P = 0.002; Fig. 2B). Gender and increase in minimum JSW after one year were shown to predict survival of the native knee joint after nine years. Conclusions: Long-term results of joint distraction for end-stage knee OA show long-lasting clinical and structural improvement with a survival of 48% after nine years of follow-up. The last reported clinical scores in patients failing treatment were still improved compared to baseline and cannot fully explain the subsequent TKA surgery. Positive predicting factors for survival of the native knee after nine years are male gender and a larger initial increase in minimum joint space width. The differences between genders may relate to different subchondral bone characteristics between men and (postmenopausal) women.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Tibiofemoral joint space narrowing: can dynamic joint stiffness 2 years after anterior cruciate ligament injury years predict narrowing 5 years after injury?

Purpose: Patients with anterior cruciate ligament (ACL) injury experience higher rates of knee osteoarthritis (OA) compared with non-injured individuals. Changes in gait biomechanics are one proposed mechanism for OA development, as small changes in load bearing position shift cartilage loading to regions not adapted to ambulatory loading resulting in gradual degradation. Dynamic joint stiffness (DJS) is a biomechanical measure that captures contributions of both active muscle contraction and passive tissue tension. People with severe knee OA ambulate with higher DJS compared to healthy controls. It is unknown if DJS is predictive of radiographic changes in people after ACL injury. The purpose of this study was to evaluate if DJS measured 2 years after ACL injury predicts minimal joint space width (mJSW) 5 years after ACL injury. We hypothesized that higher DJS 2 years after injury will predict less joint space width (JSW) 5 years after injury. Methods: As part of a larger longitudinal study, 37 subjects (13 females, age 28.1 ± 11.9 yrs,) completed gait assessment 2 years after injury and radiographs at 5 years after injury. We analyzed participants' walking patterns using an eight-camera motion capture (VICON, Oxford, UK) at 120 Hz and embedded force platform (Bertec Corp, Columbus, OH) at 1080 Hz. We used 39 retroreflective markers on bilateral lower extremities and pelvis. Participants walked overground at a self-selected gait speed maintained ± 5% across trials. Data were processed using commercial software (Visual3D; C-Motion, Germantown, MD). DJS was analyzed during loading response, defined as from the first increase in external knee flexion moment to peak knee flexion. Knee flexion angle was plotted on the X-axis and an increase in the joint angle represents an increase in knee flexion. Knee extension joint moment was plotted along the Y-axis and an increase in moment represents an increase in the net external flexion moment. A larger positive slope indicates higher DJS. Weightbearing posteroanterior (PA) bent knee (30°) radiographs were read by one researcher (JLJ) for mJSW in each compartment. Tibiofemoral JSW in the medial compartment measured from plain radiographs has been shown to be a surrogate for articular cartilage thickness, of particular concern in knee OA. Linear regression was used to test if DJS at 2 years predicted mJSW at 5 years, adjusting for sex, body mass index (BMI), and meniscal involvement. Results: The median mJSW in this study was 4.6 mm and 5.7 mm in the medial and lateral compartment respectively. Using the IKDC scale for joint space narrowing, 8 subjects had mJSW of less than 4.0 mm, and 1 subject had mJSW less than 2.0 mm in the medial compartment. In the lateral compartment, 5 subjects had mJSW less than 4.0 mm and 1 subject had mJSW less than 2.0 mm. Average DJS of the involved limb at 2 years was 0.050 ± 0.009 and was not predictive of medial or lateral mJSW at 5 years, with unadjusted R2 = 0.033 and 0.022 respectively. Adjusting for sex, BMI, and meniscal involvement, the model remained not significant (R2 = 0.107 and 0.112). Conclusions: DJS was not a predictor of mJSW in subjects 5 years after ACL injury. Previous studies found a relationship only between severe OA and DJS; we had only 2 subjects with severe OA. Additionally, our cohort had a DJS range of 0.034–0.073, less stiff than previous literature. Limitations of this study included a lack of baseline DJS or JSW measurement. Additionally, our cohort had a very wide age range at time of initial injury (14.1–49.6 years old); previous research was on older adults. It is unknown what affect age has on DJS of the knee during gait. Further research at future time points (for OA progression) or with a more homogenous age sample may provide more insight to the relationship of DJS and JSW.

Association of Mucoid Degeneration of the Anterior Cruciate Ligament at MR Imaging with Medial Tibiofemoral Osteoarthritis Progression at Radiography: Data from the Osteoarthritis Initiative.

Purpose To determine whether anterior cruciate ligament (ACL) mucoid degeneration in participants with or at risk for osteoarthritis is associated with longitudinal risk of radiographic progression of medial tibiofemoral compartment joint space loss (JSL). Materials and Methods Baseline demographic, clinical, radiographic, and Magnetic Resonance (MR) Imaging Osteoarthritis Knee Score (MOAKS) data were evaluated in 600 participants from the Osteoarthritis Initiative database. Two blinded musculoskeletal radiologists independently evaluated baseline MR images for ACL mucoid degeneration. Multiple logistic regression was used to investigate the association between ACL mucoid degeneration at MR imaging and JSL progression at radiography, defined as a minimum joint space width decrease greater than 0.7 mm (48 months; cutoff according to mean and standard deviation of 1-year minimum joint space width changes in 90 knees of reference group). Stratified analysis was performed based on baseline cartilage surface damage. Results Knees with ACL mucoid degeneration showed a greater proportion of JSL progression compared with knees with a normal ACL (64% vs 47%; P = .004). After adjustment for all demographic, clinical, radiographic, and MOAKS variables, ACL mucoid degeneration was not statistically significantly associated with JSL progression in the entire cohort (adjusted odds ratio, 1.66; 95% confidence interval: 1.00, 2.77; P = .051). In subgroup analysis, ACL mucoid degeneration was statistically significantly associated with JSL progression in participants with less baseline cartilage surface damage (maximum cartilage surface loss of ≤75% in all subregions [P = .015] and ≤4 of involved subregions with cartilage surface loss [P = .028]). Conclusion ACL mucoid degeneration in participants with or at risk for osteoarthritis is associated with progression of medial tibiofemoral compartment JSL in knees with less baseline cartilage surface area damage. © RSNA, 2018 Online supplemental material is available for this article.

Sagittal alignment and mobility of the thoracolumbar spine are associated with radiographic progression of secondary hip osteoarthritis.

To identify predictors of radiographic progression of hip osteoarthritis (OA) over 12 months among functional hip impairments and spinal alignment and mobility. Fifty female patients with secondary hip OA, excluding those with end-stage hip OA, participated in this prospective cohort study. Joint space width (JSW) of the hip was measured at baseline and 12 months later. With radiographic progression of hip OA over 12 months (>0.5mm in JSW) as dependent variable, logistic regression analyses were performed to identify predictors for hip OA progression among functional impairments of the hip and spine with and without adjustment for age, body mass index (BMI), and minimum JSW at baseline. The independent variables were hip pain, Harris hip score (HHS), hip morphological parameters, hip passive range of motion (ROM) and muscle strength, and alignment and mobility of the thoracolumbar spine at baseline. Twenty-one (42.0%) patients demonstrated radiographic progression of hip OA. Multivariable logistic regression analysis showed that larger anterior inclination of the spine in standing position (adjusted OR [95% CI], 1.37 [1.04-1.80]; P=0.028) and less thoracolumbar spine mobility (adjusted OR [95% CI], 0.96 [0.92-0.99]; P=0.037) at baseline were statistically significantly associated with radiographic progression of hip OA, even after adjustment for age, BMI, and minimum JSW. The findings suggest that spinal alignment and mobility should be considered when assessing risk and designing preventive intervention for radiographic progression of secondary hip OA.

Sensitivity to change and association of three-dimensional meniscal measures with radiographic joint space width loss in rapid clinical progression of knee osteoarthritis

ObjectiveTo determine whether 3D meniscal measures had similar sensitivity to longitudinal change as cartilage thickness; to what extent these measures are associated with longitudinal joint space width (JSW) change; and whether the latter associations differ between minimum (mJSW) and fixed-location JSW.MethodsTwo-year changes in medial meniscal position and morphology, cartilage thickness (MRI) and minimum and fixed-location JSW (radiography) were determined in 35 Osteoarthritis Initiative knees [12 men, age: 67 (51-77) years; 23 women, age: 65 (54-78) years], progressing from baseline Kellgren-Lawrence grade ≤2 to knee replacement within 3-5 years. Multiple linear regression assessed the features contributing to JSW change.ResultsMeniscal measures, cartilage thickness and JSW displayed similar sensitivity to change (standardised response mean≤|0.76|). Meniscal changes were strongly associated with JSW change (r≤|0.66|), adding ≤20% to its variance in addition to cartilage thickness change. Fixed-location JSW change (multiple r2=72%) was more strongly related to cartilage and meniscal change than mJSW (61%). Meniscal morphology explained more of fixed-location JSW and meniscal position more of mJSW.ConclusionMeniscal measures provide independent information in explaining the variance of radiographic JSW change. Fixed-location JSW appears to be more reflective of structural change than mJSW and, hence, a potentially superior measure of structural progression.Key Points• 3D positional/morphological meniscal measures change in rapidly progressing knees.• Similar sensitivity to 2-year change of quantitative meniscal/cartilage measures in rapid progression.• Changes in meniscal measures are strongly associated with radiographic JSW change.• Meniscal change provides information to explain JSW variance independent of cartilage.• Fixed-location JSW reflects structural disease stage more closely than minimum JSW.

The posterior-anterior flexed view is better than the anterior-posterior view for assessing osteoarthritis of the knee.

The aim of this study is to determine whether the posterior-anterior (PA)-flexed view improves the radiographic assessment of patients with knee pain compared with the standard standing anterior-posterior radiograph. Three hundred and sixty-five patients with knee pain underwent anterior-posterior (AP), PA flexed, lateral, and Merchant radiographs of the knee. Knees were grouped as mild (Kellgren and Lawrence [K-L] 1-2) or severe (K-L 3-4) osteoarthritis (OA) and either varus (medial compartment), valgus (lateral compartment), or patellofemoral OA. In knees with mild valgus OA on AP view (K-L 1-2), the PA flexed view was more sensitive than the AP view. The measured lateral minimal joint space width (minJSW) decreased more than 2mm in 68% of the patients, resulting in an increase in K-L grade (3 or 4). In patients with severe valgus OA and in all patients with varus and patellofemoral OA, there was no difference between AP and PA flexed view with regard to radiographic measurements or KL grade. Based on the Medicare reimbursement rate using the PA flexed view alone instead of both views reduced imaging costs by 47%. The PA flexed view better classifies the severity of lateral compartment disease in patients with mild valgus OA and provides comparable diagnostic sensitivity for joint space narrowing in varus- and patellofemoral OA. Using the PA flexed view alone was more cost effective than using the combination of AP and PA flexed imaging.

Serial Changes in the Joint Space Width and Joint Line Convergence Angle After Closed-Wedge High Tibial Osteotomy

Background: There have been little data concerning serial changes in the joint space width (JSW) and joint line convergence angle over the course of follow-up periods after closed-wedge high tibial osteotomy (CWHTO). Purpose: To evaluate serial changes in the JSW and joint line convergence angle after CWHTO. Study Design: Case series; Level of evidence, 4. Methods: A total of 100 computer-assisted CWHTOs with a minimum follow-up period of 3 years (mean, 4.4 years) were analyzed. Clinically, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was evaluated. Radiographically, the mechanical axis was measured preoperatively and postoperatively. The minimal JSW was measured as the shortest distance between the femur and the tibia. The convergence angle was measured as the angle between the tangent to the subchondral plates of the femoral condyle and the tibial plateau. Serial changes in these measurements were analyzed preoperatively; at 3 months, 6 months, 1 year, and 2 years postoperatively; and at the final follow-up. The intraclass correlation coefficients for all measurements were greater than 0.8. Results: The mean WOMAC score improved from 41.4 preoperatively to 14.9 at the final follow-up. The preoperative and postoperative mean mechanical axis was 8.1° varus and 1.6° valgus, respectively. The mean minimal JSW was 2.5, 2.9, 2.9, 3.1, 3.2, and 3.1 mm preoperatively and at 3 months, 6 months, 1 year, 2 years, and the final follow-up, respectively (P < .001). The mean convergence angle was 4.4°, 3.9°, 4.0°, 4.1°, 4.2°, and 4.3°, respectively, during the same time periods (P = .068). Conclusion: Cartilage healing, as indicated by the JSW, and clinical improvement were maintained over the minimum 3-year follow-up after CWHTO. Cartilage pressure, as indicated by the convergence angle, remained unchanged after CWHTO.

Changes in Knee Joint Space Width in Treatment with a New Hyaluronic-Based Hydrogel

AbstractObjective: Our purpose was to assess the effect of a new hyaluronic acid-based (Hymovis®) injections on joint space width narrowing in patients diagnosed with knee osteoarthritis.Methods: A prospective clinical trial was conducted in the Department of Orthopedics and Traumatology II from the Clinical County Hospital, Tîrgu Mureș, Romania. Thirty-five patients diagnosed with idiopathic knee osteoarthritis received two intraarticular injections with hyaluronic acid-based hydrogel (24 mg of hyaluronic acid/3 ml) at one-week interval. Anteroposterior radiographs were obtained before the injections, at six and twelve months after. Minimum joint space width was measured by two senior orthopaedics surgeons at each follow up. Each radiograph was measured again by the same evaluators two weeks apart.Results: Thirty-one patients were present at the final follow-up. A minor reduction in mean weight was noticed (from 82.2 kg ± 16.2 kg to 80.9 kg ± 16.0, p &gt; 0.398) without any correlation with joint space width narrowing. There were no major changes at the first follow up (6 months) regarding joint space narrowing. A reduction in joint space width was observed however at 12 months varying from 4.4 mm (SD ± 1.64, range 1.8-7.1) at the first assessment to 4.3 mm (SD ± 1.26, range 0.0-6.8) at the final follow-up but with no statistical difference (p=0.237).Conclusion: No significant modification in joint space width at the final follow-up secondarily proved that two injections of Hymovis® may slow down narrowing in the knee joint space over a one-year period.

Radiographic measurements of the hip joint and their associations with hip pain in Japanese men and women: the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study.

To investigate radiographic measurements of the hip joint and their associations with hip pain, and the prevalence of acetabular dysplasia defined by radiographic measurements of the hip joint in Japanese men and women using the large-scale population-based cohort of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study. From the baseline survey of the ROAD study (cross-sectional study), 2963 participants (1040 men, 1923 women; mean age, 70.2 years) were analyzed. All participants underwent radiographic examinations of both hips using an anteroposterior view under weight-bearing. Minimum joint space width (mJSW), central-edge (CE) angle, acetabular depth-to-width ratio (ADR), and acetabular head index (AHI) were measured. Associations between these radiographic measurements and hip pain were assessed by calculating odds ratios (ORs) using multivariable logistic-regression analysis. Acetabular dysplasia was defined as a CE angle <20°. Mean radiographic measurements of the hip joint for men were: mJSW, 3.8mm; CE angle, 30.6°; ADR, 262.1 per 1000; and AHI, 81.4%. For women, these values were: mJSW, 3.4mm; CE angle, 29.9°; ADR, 262.7 per 1000; and AHI, 81.2%. Associations were seen between hip pain and each of mJSW, CE angle, ADR, and AHI (OR 4.52, 95% confidence interval 3.45-5.97; 1.14, 1.11-1.18; 1.31, 1.24-1.40; and 1.15, 1.12-1.18, respectively). Acetabular dysplasia showed an overall prevalence of 13.9%, and was significantly more prevalent in women than in men (P=0.012). The present study of radiographic measurements of the hip joint showed that mJSW, CE angle, ADR, and AHI were associated with hip pain.

Longitudinal change in thigh muscle strength prior to and concurrent with symptomatic and radiographic knee osteoarthritis progression: data from the Osteoarthritis Initiative.

To investigate whether symptomatic and/or radiographic knee osteoarthritis (KOA) progression is associated with prior and/or concurrent change in thigh muscle strength in men or women. Osteoarthritis Initiative (OAI) participants with isometric muscle strength measurements at baseline, 2- and 4-year follow-up (n=1785: 1016 women) were grouped into 1) those with vs without symptomatic progression (i.e., increase ≥9 in WOMAC-pain [scale: 0-100]); and 2) those with vs without radiographic progression (i.e., decrease in minimum joint space width (JSW) ≥0.7mm) between year-two and year-four follow-up. Sex-specific changes in thigh muscle strength concurrent (between year-two and year-four follow-up) and prior to (between baseline and year-two follow-up) symptomatic and radiographic progression were compared between groups (progression vs no progression) using analysis of covariance, with adjustment for age and body mass index. In women, but not in men, loss in knee extensor and flexor strength was greater concurrent with symptomatic progression (extensors:-3.7%, 95% confidence interval [CI]-6.4,-0.9; flexors:-7.2% 95% CI-10.7,-3.7) than in women without symptomatic progression (extensors:-0.3%, 95% CI-1.9, 1.3, P=0.030; flexors:-2.6%, 95% CI-4.7,-0.6, P=0.018). No association was found between extensor or flexor strength loss concurrent to radiographic progression, in either men or women, nor any statistically significant association between prior change in muscle strength with symptomatic or radiographic progression. These findings suggest that there is concurrent but not prior longitudinal association between loss in muscle strength and symptomatic KOA progression that is specific to women.

Copy number loss in the region of the ASPN gene in patients with acetabular dysplasia: ASPN CNV in acetabular dysplasia.

ObjectivesWe have previously investigated an association between the genome copy number variation (CNV) and acetabular dysplasia (AD). Hip osteoarthritis is associated with a genetic polymorphism in the aspartic acid repeat in the N-terminal region of the asporin (ASPN) gene; therefore, the present study aimed to investigate whether the CNV of ASPN is involved in the pathogenesis of AD.MethodsAcetabular coverage of all subjects was evaluated using radiological findings (Sharp angle, centre-edge (CE) angle, acetabular roof obliquity (ARO) angle, and minimum joint space width). Genomic DNA was extracted from peripheral blood leukocytes. Agilent’s region-targeted high-density oligonucleotide tiling microarray was used to analyse 64 female AD patients and 32 female control subjects. All statistical analyses were performed using EZR software (Fisher’s exact probability test, Pearson’s correlation test, and Student’s t-test).ResultsCNV analysis of the ASPN gene revealed a copy number loss in significantly more AD patients (9/64) than control subjects (0/32; p = 0.0212). This loss occurred within a 60 kb region on 9q22.31, which harbours the gene for ASPN. The mean radiological parameters of these AD patients were significantly worse than those of the other subjects (Sharp angle, p = 0.0056; CE angle, p = 0.0076; ARO angle, p = 0.0065), and all nine patients required operative therapy such as total hip arthroplasty or pelvic osteotomy. Moreover, six of these nine patients had a history of operative or conservative therapy for developmental dysplasia of the hip.ConclusionsCopy number loss within the region harbouring the ASPN gene on 9q22.31 is associated with severe AD. A copy number loss in the ASPN gene region may play a role in the aetiology of severe AD.Cite this article: T. Sekimoto, M. Ishii, M. Emi, S. Kurogi, T. Funamoto, Y. Yonezawa, T. Tajima, T. Sakamoto, H. Hamada, E. Chosa. Copy number loss in the region of the ASPN gene in patients with acetabular dysplasia: ASPN CNV in acetabular dysplasia. Bone Joint Res 2017;6:439–445. DOI: 10.1302/2046-3758.67.BJR-2016-0094.R1.

Joint Space Width and Osteoarthritis in Patients Undergoing Hip Arthroscopy

AbstractPreoperative hip joint space width (JSW) of ≤2 mm on plain radiography has been shown to be predictive of intraoperative findings of osteoarthritis, worse functional outcomes, and failure to total hip arthroplasty following hip arthroscopy. However, there is no evidence to suggest that hip joint space greater than 2 mm can definitively rule out the presence of osteoarthritis. We hypothesize that a preoperative JSW of 2 mm or greater does not reliably rule out the presence of high-grade arthritis on hip arthroscopy. Retrospective review of 50 patients who underwent hip arthroscopy between January 11, 2010, and January 3, 2015, at a single institution was performed. Preoperative, standing anteroposterior hip radiographs were reviewed to determine the minimum hip JSW of each operative hip. Operative notes and images were reviewed to determine the Outerbridge classification of cartilage changes on both the acetabulum and femoral head for each patient. High-grade arthritis was defined as a minimum of grade 3 changes on either the femoral head or the acetabulum, which was required for inclusion in the study. The sensitivity of a JSW of 2 mm or less on preoperative radiographs to diagnose a patient with grade 3, grade 4, and grade 3 or 4 arthritis was calculated. Linear regression was used to test for an association between Outerbridge grading and the radiographic minimum JSW. The mean JSW for all patients was 3.5 ± 1.2 mm (range: 0–5.5 mm). Regression found an inverse relationship between joint space and the arthroscopic grading of the articular surfaces (p = 0.0031). However, a preoperative JSW of ≤ 2 mm was only 14.3% sensitive (95% confidence interval [CI] 2.6–51.3%) for predicting Outerbridge grade 3 changes, 7.3% sensitive (95% CI: 2.5–19.4%) for predicting Outerbridge grade 4 changes, and 8.3% sensitive (95% CI: 3.3–20.6%) for predicting Outerbridge grade 3 or 4 changes. The threshold of ≤2 mm of hip JSW on plain radiographs has poor sensitivity for predicting the existence of high-grade arthritis.

Longitudinal association between foot and ankle symptoms and worsening of symptomatic radiographic knee osteoarthritis: data from the osteoarthritis initiative.

To assess whether foot and/or ankle symptoms are associated with an increased risk of worsening of knee pain and radiographic change in people with knee osteoarthritis (OA). The presence and laterality of foot/ankle symptoms were recorded at baseline in 1368 participants from the Osteoarthritis Initiative (OAI) with symptomatic radiographic knee OA. Knee pain severity (measured using the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale) and minimum medial tibiofemoral joint space (minJSW) width measured on X-ray were assessed yearly over the subsequent 4years. Associations between foot/ankle symptoms and worsening of (1) knee pain, and (2) both knee pain and minJSW (i.e., symptomatic radiographic knee OA) were assessed using logistic regression. Foot/ankle symptoms in either foot/ankle significantly increased the odds of knee pain worsening (adjusted OR 1.54, 95% CI 1.25 to 1.91). Laterality analysis showed ipsilateral (adjusted OR 1.50, 95% CI 1.07 to 2.10), contralateral (adjusted OR 1.44, 95% CI 1.02 to 2.06) and bilateral foot/ankle symptoms (adjusted OR 1.61, 95% CI 1.22 to 2.13) were all associated with knee pain worsening in the follow up period. There was no association between foot/ankle symptoms and worsening of symptomatic radiographic knee OA. The presence of foot/ankle symptoms in people with symptomatic radiographic knee OA was associated with increased risk of knee pain worsening, but not worsening of symptomatic radiographic knee OA, over the subsequent 4years. Future studies should investigate whether treatment of foot/ankle symptoms reduces the risk of knee pain worsening in people with knee OA.

MP06: Use of ultrasound and x-ray to predict improvement in hip osteoarthritis symptoms following intra-articular steroid injection

Introduction: Intra-articular steroid injection (IASI) is commonly used in the emergency department for management of osteoarthritis (OA) symptoms. Hip IASI carries risks, such as avascular necrosis, and there is currently no reliable way to predict long-term response of a patient’s OA to IASI. Ultrasound (US) conveniently assesses for active arthropathy by detecting effusion-synovitis, and x-ray (XR) is useful for visualizing bone-related changes. We investigated the extent that a response to hip IASI could be predicted from baseline OA patient clinical and physical features alongside US and XR imaging features. Methods: 97 consenting patients with symptomatic hip OA presenting for hip IASI were evaluated at baseline (XR and US) and again 8-weeks after IASI (US only). Self-reported pain (WOMAC), hip range of motion (ROM) were measured at baseline and follow up. On US images we quantified joint effusion and synovial thickening, i.e., “effusion-synovitis”, by the bone-capsule distance (BCD) at the apex of the femoral head from outer femoral cortex to outer synovium. On XR, we measured minimum joint space width (cm) and Kellgren-Lawrence (K-L) Grade for osteophytes and sclerotic changes. Results: In our 97 patients (43 female) aged 28-87 years (mean 59+/-13 years, K-L grades averaged 2.5+/-1.5, and US BCD averaged 5.9+/-2.0 mm. We performed multiple linear regression using age, sex, BMI, ROM of hip flexion, US BCD, radiographic joint space width and K-L grade against the dependent variable, change in WOMAC pain subscore (R=0.587, P=0.002). We compared the response predicted by this model to the actual change in WOMAC pain. At a threshold value of -20% for minimal clinically important difference, 35/97 patients were responders, and a 2x2 table gave 67% overall model predictive accuracy, 61% sensitivity, and 71% specificity. Likelihood ratio for a positive response (LR+) was 2.13. Conclusion: Combining radiographic information on structural damage, US information on active arthropathy, and demographics correctly predicted about two-thirds of the patients that would benefit from IASI after 8 weeks. A patient with hip OA that met our model criteria was more than twice as likely to respond to IASI. With further model refinement, effective, personalized evidence-based management of symptomatic hip OA is possible using XR and hip US, which could both be performed during an ER visit.

Presence of IL-17 in synovial fluid identifies a potential inflammatory osteoarthritic phenotype

PurposeOsteoarthritis (OA) is a common and heterogeneous arthritic disorder. Patients suffer pain and their joints are characterized by articular cartilage loss and osteophyte formation. Risk factors for OA include age and obesity with inflammation identified as a key mediator of disease pathogenesis. Interleukin-17A (IL-17) is a pro-inflammatory cytokine that has been implicated in inflammatory diseases such as rheumatoid arthritis. IL-17 can upregulate expression of inflammatory cytokines and adipocytokines. The aim of this study was to evaluate IL-17 levels in the synovial fluid of patients with end-stage knee and hip OA in relation to inflammation- and pain-related cytokines and adipocytokines in synovial fluid and serum, and clinical and radiographic disease parameters.MethodsThis is a cross-sectional study of 152 patients undergoing total hip and knee arthroplasty for OA. IL-17, IL-6, leptin, adiponectin, visfatin, resistin, C-C Motif Chemokine Ligand 2 (CCL2), C-C Motif Chemokine Ligand 7 (CCL7) and nerve growth factor (NGF) protein levels were measured in synovial fluid and serum using enzyme-linked immunosorbent assay (ELISA). Baseline characteristics included age, sex, body mass index, co-morbidities, pain and function, and radiographic analyses (OA features, K&L grade, minimal joint space width).Results14 patients (9.2%) had detectable IL-17 in synovial fluid. These patients had significantly higher median concentrations of IL-6, leptin, resistin, CCL7 and NGF. Osteophytes, sclerosis and minimum joint space width were significantly reduced in patients with detectable IL-17 in synovial fluid. No differences were found in pain, function and comorbidities. IL-17 concentrations in synovial fluid and serum were moderately correlated (r = 0.482).ConclusionThe presence of IL-17 in the synovial fluid therefore identifies a substantial subset of primary end-stage OA patients with distinct biological and clinical features. Stratification of patients on the basis of IL-17 may identify those responsive to therapeutic targeting.

Daily cumulative hip load is associated with radiographic progression of secondary hip osteoarthritis

Purpose: Hip osteoarthritis (OA) is a chronic disease; however, the mechanical risk factor during gait for hip OA progression has not been identified. The purpose of this study was to evaluate the association between mechanical load during gait at baseline and subsequent radiographic progression of hip OA over 12 months. Methods: Fifty patients with secondary hip OA except for end-stage hip OA participated in this prospective cohort study. To assess the change in joint space width (JSW), films at baseline and approximately 12 months later were paired by patients but blinded as to patient and sequence to the reader to avoid bias. Radiographic progression of hip OA was defined as reduction of more than 0.5 mm per year in JSW. Intrarater reliability [ICC (1,1)] of the JSW measurement was 0.99, and minimum detectable change of the JSW was 0.39. With radiographic progression of hip OA as dependent variable (yes/no), univariate and multivariate logistic regression analyses were performed. Independent variables were age, body weight, hip pain (visual analog scale), radiographic variables (CE angle, Sharp angle, acetabular head index, and acetabular roof obliquity), hip impairments (range of motion and muscle strength), and gait-related variables. Gait-related variables were recorded using an 8-camera Vicon motion system at a sampling rate of 200 Hz, and using force plates at a sampling rate of 1,000 Hz. A total of 20 reflective markers were placed by a single experienced examiner. At least 3 successful trials for each patient were recorded for analysis. Gait-related variables included steps per day, gait speed, peak hip joint moment, hip joint moment impulse, and daily cumulative hip load in 3 planes. The number of steps was recorded by a pedometer for 7 consecutive typical days within a month from the day of gait analysis. Daily cumulative hip load was calculated as a product of the non-normalized hip moment impulse in each of 3 planes and the mean number of steps per day for the affected limb (number of steps/day divided by 2). The criterion for inclusion in multivariate analysis was P < 0.1 in univariate logistic regression analysis. Since age and body weight at baseline can be potential confounders, those 2 variables were included in the multivariate model. A P value < 0.05 was considered statistical significant. Results: Of the 50 patients, 21 (42.0%) were classified into the progression group. Change in JSW in the progression group was 1.3 ± 0.8 mm. In univariate logistic regression analysis, increased daily cumulative hip load in the frontal plane at baseline was significantly associated with progression of hip OA (p = 0.038). On average, the cumulative hip load in the frontal plane in the progression group was approximately 1.4 times higher than that in the no progression group (Fig. 1). Minimum JSW (p = 0.066) and steps per day (p = 0.062) were also potential variables for multivariate logistic regression analysis (Fig. 1). The correlation coefficient (ρ = 0.74) between steps per day and daily cumulative hip load in the frontal plane was over the threshold for multicollinearity. Therefore, minimum JSW and daily cumulative hip load in the frontal plane were entered into multivariate logistic regression analysis. In multivariate analysis, reduced minimum JSW and increased daily cumulative hip load in the frontal plane at baseline were associated with radiographic hip OA progression independently. Even after adjustment for age and body weight, minimum JSW and daily cumulative hip load in the frontal plane were remained in the model (Table 1). Conclusions: This study provides evidence that higher daily cumulative hip load at baseline, particularly in the frontal plane, is associated with radiographic progression of hip OA defined by a > 0.5-mm cartilage thickness loss in 12 months. Our findings will help identify patients with higher risk of hip OA progression and clarify the target of intervention to slow hip OA progression.Table 1Multivariate logistic regression predicting the progression of hip osteoarthritisOR (95% CI)P-valueOR (95% CI) adjusted for age and body weightP-valueMinimum JSW at baseline (mm)0.63 (0.40–0.99)0.0460.49 (0.25–0.94)0.031Daily cumulative hip load in frontal plane (kNm seconds)1.02 (1.00–1.04)0.0301.03 (1.01–1.05)0.013 Open table in a new tab

Genetic association studies in osteoarthritis: is it fairytale?

Osteoarthritis is a common complex disorder with a strong genetic component. Other identified risk factors such as increasing age and overweight do not fully explain the risk of osteoarthritis. Here, we highlight the main findings from genetic association studies on osteoarthritis to date. Currently, genetic association studies have identified 21 independent susceptibility loci for osteoarthritis. Studies have focused on hip, knee and hand osteoarthritis, as well as posttotal joint replacement and minimum joint space width, a proxy for cartilage thickness. Four distinct loci have recently been identified in a genome-wide association scan on minimum joint space width. The role of mitochondrial DNA variants has been the focus of a recent meta-analysis. Findings have previously been mixed, however, this study suggests a plausible involvement of mitochondrial DNA in the progression of radiographic knee osteoarthritis. Identifying genetic locations of interest provides a framework upon which to base future studies, for example replication analysis and functional work. Genetic association studies have shaped and will continue to shape research in this field. Improving the understanding of osteoarthritis could improve the diagnosis and treatment of the disease and improve quality of life for many individuals.