Survival analysis on subchondral bone length for total knee replacement.

OBJECTIVE: Use subchondral bone length (SBL), a new MRI-derived measure that reflects the extent of cartilage loss and bone flattening, to predict the risk of progression to total knee replacement (TKR). METHODS: We employed baseline MRI data from the Osteoarthritis Initiative (OAI), focusing on 760 men and 1214 women with bone marrow lesions (BMLs) and joint space narrowing (JSN) scores, to predict the progression to TKR. To minimize bias from analyzing both knees of a participant, only the knee with a higher Kellgren-Lawrence (KL) grade was considered, given its greater potential need for TKR. We utilized the Kaplan-Meier survival curves and Cox proportional hazards models, incorporating raw and normalized values of SBL, JSN, and BML as predictors. The study included subgroup analyses for different demographics and clinical characteristics, using models for raw and normalized SBL (merged, femoral, tibial), BML (merged, femoral, tibial), and JSN (medial and lateral compartments). Model performance was evaluated using the time-dependent area under the curve (AUC), Brier score, and Concordance index to gauge accuracy, calibration, and discriminatory power. Knee joint and region-level analyses were conducted to determine the effectiveness of SBL, JSN, and BML in predicting TKR risk. RESULTS: The SBL model, incorporating data from both the femur and tibia, demonstrated a predictive capacity for TKR that closely matched the performance of the BML score and the JSN grade. The Concordance index of the SBL model was 0.764, closely mirroring the BML's 0.759 and slightly below JSN's 0.788. The Brier score for the SBL model stood at 0.069, showing comparability with BML's 0.073 and a minor difference from JSN's 0.067. Regarding the AUC, the SBL model achieved 0.803, nearly identical to BML's 0.802 and slightly lower than JSN's 0.827. CONCLUSION: SBL's capacity to predict the risk of progression to TKR highlights its potential as an effective imaging biomarker for knee osteoarthritis.

Joint-preserving effect and patient-reported outcomes of transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head.

BACKGROUND: This study assessed the hip survival rate and patient-reported outcome measures (PROMs) of transtrochanteric curved varus osteotomy (CVO) for osteonecrosis of the femoral head (ONFH) compared with those of conservative management. METHODS: The CVO group comprised 32 consecutive patients (39 hips) who underwent CVO for ONFH between 2000 and 2011. The conservative group consisted of 36 consecutive patients (37 hips) who were managed conservatively for at least 1 year after collapse and who had ONFH classified by the Japanese Investigation Committee of Health and Welfare as type B or C1, for which CVO is indicated. Kaplan-Meier analysis of hip survival used any ONFH-related therapeutic surgery as the endpoint. PROMs were evaluated for all patients with surviving hips and radiographs available at the latest follow-up. RESULT: The 10-year hip survival rate in the CVO group was 86.7%, which was significantly higher than the 51.0% 5-year survival rate in the conservative group (p < 0.0001). The Oxford Hip Score and UCLA Activity Score were significantly better in the CVO group without joint space narrowing than in the conservative group, with no significant differences between the CVO group with joint space narrowing and the conservative group. CONCLUSION: CVO could preserve hip joints more effectively than conservative follow-up after collapse, although the presence of joint space narrowing could reduce satisfaction levels even in patients with long-term hip survival.

Subtle Radiographic Progression at Six Months Can Be Detected Using Automated Quantitative Software in Rheumatoid Arthritis While Receiving Tocilizumab.

OBJECTIVES: We investigated whether our in-house software equipped with partial image phase-only correlation (PIPOC) can detect subtle radiographic joint space narrowing (JSN) progression at six months and predict JSN progression in rheumatoid arthritis (RA) patients receiving Tocilizumab. METHODS: The study included 39 RA patients who were treated with Tocilizumab. Radiological progression of the metacarpophalangeal and the proximal interphalangeal joints was evaluated according to the Genant-modified Sharp score (GSS) at 0, 6, and 12 months. Automatic measurements were performed with the software. We validated the software in terms of accuracy in detecting the JSN progression. RESULTS: The success rate of the software for joint space width (JSW) measurement was 96.8% (449/464). The 0-12-month JSW change by the software was significantly greater in joints with the 0-6-month PIPOC (+) group than the 0-6-month PIPOC (-) group (p < 0.001). The 0-12-month JSW change by the software was 0-12-month GSS (+) than with 0-12-month GSS (-) (p = 0.02). Here, "(+)" indicates the JSN progression during the follow-up period. Meanwhile, "(-)" indicates no JSN progression during the follow-up period. Linear regression tests showed significant correlations between the 0-6-month and the 0-12-month PIPOC in the left 2nd and 3rd MCP joints (R2 = 0.554 and 0.420, respectively). CONCLUSIONS: Our in-house software equipped with PIPOC could predict subsequent JSN progression with only short-term observations.

Assessment of a novel deep learning-based software developed for automatic feature extraction and grading of radiographic knee osteoarthritis.

BACKGROUND: The Kellgren-Lawrence (KL) grading system is the most widely used method to classify the severity of osteoarthritis (OA) of the knee. However, due to ambiguity of terminology, the KL system showed inferior inter- and intra-observer reliability. For a more reliable evaluation, we recently developed novel deep learning (DL) software known as MediAI-OA to extract each radiographic feature of knee OA and to grade OA severity based on the KL system. METHODS: This research used data from the Osteoarthritis Initiative for training and validation of MediAI-OA. 44,193 radiographs and 810 radiographs were set as the training data and used as validation data, respectively. This AI model was developed to automatically quantify the degree of joint space narrowing (JSN) of medial and lateral tibiofemoral joint, to automatically detect osteophytes in four regions (medial distal femur, lateral distal femur, medial proximal tibia and lateral proximal tibia) of the knee joint, to classify the KL grade, and present the results of these three OA features together. The model was tested by using 400 test datasets, and the results were compared to the ground truth. The accuracy of the JSN quantification and osteophyte detection was evaluated. The KL grade classification performance was evaluated by precision, recall, F1 score, accuracy, and Cohen's kappa coefficient. In addition, we defined KL grade 2 or higher as clinically significant OA, and accuracy of OA diagnosis were obtained. RESULTS: The mean squared error of JSN rate quantification was 0.067 and average osteophyte detection accuracy of the MediAI-OA was 0.84. The accuracy of KL grading was 0.83, and the kappa coefficient between the AI model and ground truth was 0.768, which demonstrated substantial consistency. The OA diagnosis accuracy of this software was 0.92. CONCLUSIONS: The novel DL software known as MediAI-OA demonstrated satisfactory performance comparable to that of experienced orthopedic surgeons and radiologists for analyzing features of knee OA, KL grading and OA diagnosis. Therefore, reliable KL grading can be performed and the burden of the radiologist can be reduced by using MediAI-OA.

Effect of spinal fusion on joint space narrowing of the hip: comparison among non-fusion, short fusion, and middle or long fusion.

BACKGROUND: Lumbar fusion corrects spinal deformities and improves spinal complications. Hip osteoarthritis (OA) is strongly correlated with spinal mobility, and joint space narrowing of the hip after spinal fusion has gained attention. This study aimed to elucidate the effect of spinal fusion on hip joint space narrowing. MATERIALS AND METHODS: We retrospectively examined 530 hips of 270 patients who underwent spinal surgery. All the patients underwent whole-spine radiography before and at the final follow-up. Patients were divided into three groups (N group: non-spinal fusion, S group: up to three interbody fusions, and L group: more than four interbody fusions). The rates of joint space narrowing, spinal parameters (sagittal vertical axis, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence), and limb length discrepancy at the final follow-up were compared. A multilinear regression analysis was performed to identify the risk factors for the rate of joint space narrowing. RESULTS: The rate of joint space narrowing was significantly higher in the L group than in the N and S groups (P < 0.001). No significant difference in the rate of joint space narrowing was observed between the N and S groups. Multiple linear regression analysis revealed that the number of fusion levels (p < 0.05) and follow-up period (p < 0.001) were independent risk factors for joint space narrowing. Spinal parameters at the final follow-up were not independent risk factors. CONCLUSIONS: Long spinal fusion (more than four levels) led to significantly greater joint space narrowing of the hip than short (up to three levels) or no fusion. Spinal alignment did not affect joint space narrowing of the hip. Surgeons should be aware that more than four interbody fusions may result in worse joint space narrowing of the hip. LEVEL OF EVIDENCE: IV, retrospective study.

Medial unicondylar knee arthroplasty should be reserved for patients with complete joint space collapse.

PURPOSE: To determine whether preoperative radiologic joint space width (JSW) is related to the outcome of medial unicondylar knee arthroplasty (UKA) (primary hypothesis). METHODS: A retrospective comparative analysis was performed. One group was comprised of UKA patients with preoperative JSW 0-1 mm. Another group was made up of patients with preoperative JSW ≥ 2 mm (range 0-4 mm). The JSW was measured from preoperative weight-bearing Schuss-view radiographs. The clinical outcome was determined with the Western Ontario and MacMaster Universities (WOMAC) Osteoarthritis Index score preoperatively and 1 year after medial UKA. Implant survival data were obtained from the arthroplasty register of Tyrol. RESULTS: There were 80 patients with a preoperative JSW 0-1 mm (age 66, BMI 27.8) and 70 patients with a preoperative JSW ≥ 2 mm (age 64, IQR 15, BMI 28.1). WOMAC total was 10 ± 10 in patients with 0-1 mm JSW and 25 ± 47 in patients with ≥ 2 mm JSW at 1 year postoperative (p = 0.052). WOMAC pain at 1 year postoperative was 7 ± 16 in patients with 0-1 mm JSW and 18 ± 46 in patients with ≥ 2 mm JSW (p = 0.047). WOMAC function at 1 year postoperative was 10 ± 9 in patients with 0-1 mm JSW and 17 ± 51 in patients with ≥ 2 mm JSW (p = 0.048). In patients with 0-1 mm JSW 5 year prosthesis survival was 92.3% and in patients with ≥ 2 mm JSW, it was 81.1% (p = 0.016). CONCLUSIONS: In patients with preoperative complete joint space collapse (0-1 mm JSW), clinical outcome was superior to that of patients with incomplete joint space collapse. This was true for both 1 year postoperative WOMAC pain and WOMAC function and for 5 year implant survival rates. On the basis of our findings, it is recommended that 'complete joint space collapse' especially be used to achieve best clinical outcome in medial UKA surgery. LEVEL OF EVIDENCE: IV.

Characterization of the mid-coronal plane method for measurement of radiographic change in knee joint space width across different levels of image parallax.

OBJECTIVE: Radiographic measurement of the change in knee joint space width (ΔJSW) is often affected by image parallax, which causes an apparent exaggeration of JSW due to projectional differences. This issue with parallax (quantified by intermargin distance) can in part be addressed with a novel mid-coronal plane (MCP) measurement method. The objectives of the study were to determine 1) accuracy and 2) reproducibility of the MCP method, and 3) compare the MCP method to that used in the Osteoarthritis Initiative (OAI) for different categories of parallax. METHODS: Posteroanterior radiographs (n = 70) with known JSW were digitally reconstructed from CT images of cadaver knees and used to determine the accuracy of ΔJSW using the MCP method for parallax categories of None, Mild/Moderate, and Severe. Reproducibility was determined from pairs of clinical radiographs selected from the OAI (n = 170). The MCP method was also compared to the OAI methodology. Both reproducibility and agreement were characterized by Bland-Altman analysis and intraclass correlation coefficients (ICC). RESULTS: The MCP method was accurate to 0.11 mm in cases with no parallax, and 0.18 mm across all categories of parallax for medial and lateral compartments. Reproducibility of the MCP method was graded "excellent" (ICC 0.98, 95% CI [0.98, 0.99]). The MCP results agreed very well with the OAI (ICC 0.92, 95% CI [0.89, 0.94]), with mean absolute differences between methods increasing with increasing parallax. CONCLUSION: The MCP method is an accurate, reproducible alternative to the OAI method for multi-center clinical trials where subject and X-ray beam positioning may be variable.

Assessment of radiographic progression in patients with rheumatoid arthritis treated with tofacitinib in long-term studies.

OBJECTIVES: Tofacitinib is an oral Janus kinase inhibitor for the treatment of RA. We evaluated radiographic progression in tofacitinib-treated patients with RA for up to 3 years in two pooled long-term extension (LTE) studies (ORAL Sequel; A3921041) (primary analysis), and for up to 5 years using data integrated from one phase (P)2 (A3921068), two P3 (ORAL Start; ORAL Scan) and two LTE studies (exploratory analysis). METHODS: In LTE studies, patients received tofacitinib 5 mg twice daily (BID) or 10 mg BID as monotherapy or with conventional synthetic (cs)DMARDs. Radiographic outcomes up to 3 years: least squares mean (LSM) change from baseline in van der Heijde modified Total Sharp Score (ΔmTSS), erosion score (ΔES) and joint space narrowing (ΔJSN) score; proportion of patients with no radiographic progression (ΔmTSS ≤0.5); proportion of patients with no new erosions (ΔES ≤0.5). ΔmTSS was evaluated for up to 5 years in an exploratory analysis. RESULTS: For all tofacitinib-treated patients with radiographic data available at LTE month 36 (n = 414), LSM ΔmTSS was 1.14, LSM ΔES was 0.66, LSM ΔJSN was 0.74, and 74.3% and 86.2% of patients showed no radiographic progression and no new erosions, respectively. Similar values were observed regardless of tofacitinib dose, or whether patients received tofacitinib as monotherapy or with csDMARDs. In an exploratory analysis of integrated P2/P3/LTE studies, LSM ΔmTSS was 3.34 at month 60 (n = 269). CONCLUSION: Limited progression of structural damage was observed in tofacitinib-treated patients up to 5 years, with similar results for tofacitinib used as monotherapy or combination therapy up to 3 years. TRIAL REGISTRATION: ClinicalTrials.gov (http://clinicaltrials.gov): NCT01164579; NCT01039688; NCT00847613; NCT00413699; NCT00661661.

Quantification of Joint Space Width Difference on Radiography Via Phase-Only Correlation (POC) Analysis: a Phantom Study Comparing with Various Tomographical Modalities Using Conventional Margin-Contouring.

Several visual scoring methods are currently used to assess progression of rheumatoid arthritis (RA) on radiography. However, they are limited by its subjectivity and insufficient sensitivity. We have developed an original measurement system which uses a technique called phase-only correlation (POC). The purpose of this study is to validate the system by using a phantom simulating the joint of RA patients.A micrometer measurement apparatus that can adjust arbitrary joint space width (JSW) in a phantom joint was developed to define true JSW. The phantom was scanned with radiography, 320 multi detector CT (MDCT), high-resolution peripheral quantitative CT (HR-pQCT), cone beam CT (CBCT), and tomosynthesis. The width was adjusted to the average size of a women's metacarpophalangeal joint, from 1.2 to 2.2 mm with increments of 0.1 mm and 0.01 mm. Radiographical images were analyzed by the POC-based system and manual method, and images from various tomographical modalities were measured via the automatic margin detection method. Correlation coefficients between true JSW difference and measured JSW difference were all strong at 0.1 mm intervals with radiography (POC-based system and manual method), CBCT, 320MDCT, HR-pQCT, and tomosynthesis. At 0.01 mm intervals, radiography (POC-based system), 320MDCT, and HR-pQCT had strong correlations, while radiography (manual method) and CBCT had low correlations, and tomosynthesis had no statistically significant correlation. The smallest detectable changes for radiography (POC-based system), radiography (manual method), 320MDCT, HR-pQCT, CBCT, and tomosynthesis were 0.020 mm, 0.041 mm, 0.076 mm, 0.077 mm, 0.057 mm, and 0.087 mm, respectively. We conclude that radiography analyzed with the POC-based system might sensitively detect minute joint space changes of the finger joint.

A low cartilage formation and repair endotype predicts radiographic progression of symptomatic knee osteoarthritis.

BACKGROUND: Osteoarthritis (OA) is a disease with multiple endotypes. A hallmark of OA is loss of cartilage; however, it is evident that the rate of cartilage loss differs among patients, which may partly be attributed to differential capacity for cartilage repair. We hypothesize that a low cartilage repair endotype exists and that such endotypes are more likely to progress radiographically. The aim of this study is to examine the associations of level of cartilage formation with OA severity and radiographic OA progression. We used the blood-based marker PRO-C2, reflecting type II collagen formation, to assess levels of cartilage formation. MATERIALS AND METHODS: The type II collagen propeptide PRO-C2 was measured in the serum/plasma of knee OA subjects from New York University (NYU, n = 106) and a subcohort of the phase III oral salmon calcitonin (sCT) trial SMC021-2301 (SMC, n = 147). Risk of radiographic medial joint space narrowing (JSN) over 24 months was compared between quartiles (very low, low, moderate, and high) of PRO-C2. Associations were adjusted for age, gender, BMI, race, baseline pain levels, and baseline joint space width. RESULTS: In both the NYU and SMC cohorts, subjects with low PRO-C2 levels had greater JSN compared with subjects with high PRO-C2. Mean difference in JSN between subjects with very low and high levels of PRO-C2 was 0.65 mm (p = 0.002), corresponding to a 3.4 (1.4-8.6)-fold higher risk of progression. There was no significant effect of sCT treatment, compared with placebo, on JSN over 2 years before stratification based on baseline PRO-C2. However, there were proportionately fewer progressors in the sCT arm of the very low/low PRO-C2 group compared with the moderate/high group (Chi squared = 6.5, p = 0.011). CONCLUSION: Serum/plasma level of type II collagen formation, PRO-C2, may be an objective indicator of a low cartilage repair endotype, displaying radiographic progression and superior response to a proanabolic drug. LEVEL OF EVIDENCE: Level III post hoc exploratory analysis of one longitudinal cohort and a sub-study from one phase III clinical trial.

A novel quantitative metric for joint space width: data from the Osteoarthritis Initiative (OAI).

OBJECTIVE: Joint space width (JSW) has been the gold standard to assess loss of cartilage in knee osteoarthritis (OA). Here we describe a novel quantitative measure of joint space width: standardized JSW (stdJSW). We assess the performance of this quantitative metric for JSW at tracking Osteoarthritis Research Society International (OARSI) joint space narrowing grade (JSN) changes and provide reference values for different JSN grades and their annual change. METHODS: We collected 18,934 individual knee images along with JSW and JSN readings from baseline up to month 48 (4 follow-ups) from the OAI study. Standardized JSW and 12-month JSN grade changes were calculated for each knee. For each JSN grade and 12-month grade change, the distribution of JSW loss was calculated for JSW and stdJSW. Area under the ROC curves was calculated on discrimination between different JSN grades for JSW and stdJSW. Standardized response mean (SRM) was used to compare the responsiveness of the two measures to changes in JSN grade. RESULTS: The areas under the receiver operating characteristic (ROC) curve (AUC) for stdJSW at discriminating between successive JSN grades were AUCstdJSW = 0.87, 0.95, and 0.96, for JSN>0, JSN>1 and JSN>2, respectively, whereas these were AUCfJSW = 0.79, 0.90, 0.98 for absolute JSW. We find that standardized JSW is significantly more responsive than absolute JSW, as measured by the SRM. CONCLUSIONS: Our results show that stdJSW outperforms absolute JSW at discriminating and tracking changes in JSN and further that this effect is in part because stdJSW cancels JSW variations attributed to patient height variations.

A simplified radiographic score effectively predicts radiographic progression of early arthritis in a large nationwide French cohort.

OBJECTIVE: Evaluating radiographic progression is a key component of the follow-up of patients with RA. Existing scores are ill-suited to everyday clinical practice. The objective here was to validate a new simplified radiographic score (SRS) for evaluating radiographic progression in patients with early arthritis. METHODS: Patients with arthritis of <6 months' duration were included in the large, prospective, nationwide, French ESPOIR cohort. Radiographs of the hands and feet were obtained at inclusion then 1 and 5 years later. The modified Sharp scores and SRS were determined by blinded readers. Interobserver reliability and intraobserver repeatability of each score, as well as agreement between the two scores, were assessed by computing the intraclass correlation coefficients. The rates of progression over the first year and the next 4 years were determined. RESULTS: The 506 patients with complete data for the first 5 years were included. At inclusion, the intraclass correlation coefficient between the two scores was good for erosions (0.715, P < 0.001), joint space narrowing (0.892, P < 0.001) and the total score (0.896, P < 0.001). Agreement between the two scores was also good for radiographic progression after 1 year (0.781, P < 0.001). The SRS had good positive and negative predictive values for slow and for rapid progression. SRS determination was less time consuming. CONCLUSION: The SRS is effective for monitoring radiographic progression in early arthritis and is easier to use and less time-consuming than the Sharp score. The usefulness of the SRS in clinical practice deserves further evaluation.

Arthroscopic osteocapsular arthroplasty for advanced-stage primary osteoarthritis of the elbow using a computed tomography-based classification.

HYPOTHESIS: Arthroscopic osteocapsular arthroplasty for stage III osteoarthritis (advanced stage) shows worse clinical and radiologic outcomes compared with stage I or II according to computed tomography (CT)-based classification. METHODS: Clinical and radiologic outcomes in 65 patients treated with arthroscopic osteocapsular arthroplasty were retrospectively analyzed for range of motion (ROM) arc, functional score (Mayo Elbow Performance Score [MEPS]), and pain score (visual analog scale [VAS]). Patients were classified into stage I or II (n = 44) and stage III (n = 21) groups according to CT-based classification, and postoperative clinical outcomes and complications were analyzed. RESULTS: Mean follow-up duration was 32.9 ± 13.7 months (range, 24-69). The average patient age was 52 ± 10 years (range, 40-63). Improvements from preoperative to final follow-up were seen in the overall ROM-flexion from 94° ± 19° to 129° ± 14° (P < .01), ROM-extension from 25° ± 12° to 14° ± 7° (P < .01), MEPS from 45 ± 13 to 78 ± 14 (P < .01), and VAS score from 6.3 ± 1.6 to 3.1 ± 1.4 (P < .01). Subgroup analysis using the CT-based classification revealed that stage III led to worsened VAS score and MEPS than stage I or II. CONCLUSIONS: Arthroscopic osteocapsular arthroplasty can be recommended for its favorable overall treatment outcomes for elbow osteoarthritis. However, stage III shows worse clinical and radiologic outcomes compared with stage I or II according to CT-based classification.

Validation of Fully Automatic Quantitative Software for Finger Joint Space Narrowing Progression for Rheumatoid Arthritis Patients.

In rheumatoid arthritis (RA), the radiographic progression of joint space narrowing (JSN) is evaluated using visual assessments. However, those methods are complicated and time-consuming. We developed an automatic system that can detect joint locations and compute the joint space difference index (JSDI), which was defined as the chronological change in JSN between two radiographs. The purpose of this study was to establish the validity of the software that automatically evaluates the temporal change of JSN. This study consisted of 39 patients with RA. All patients were treated with tocilizumab and underwent hand radiography (left and right hand separately) at 0, 6, and 12 months. The JSN was evaluated using mTSS (modified Total Sharp Score) by one musculoskeletal radiologist as well as our automatic system. Software measurement showed that JSDI between 0 and 12 months was significantly higher than that between 0 and 6 months (p < 0.01). While, there was no significant difference in mTSS between 0, 6, and 12 months. The group with higher disease activity at 0 months had significantly higher JSDI between 0 and 6 months than that with lower disease activity (p = 0.02). The automatic software can evaluate JSN progression of RA patients in the finger joint on X-ray.

Differences in Baseline Joint Moments and Muscle Activation Patterns Associated With Knee Osteoarthritis Progression When Defined Using a Clinical Versus a Structural Outcome.

Both structural and clinical changes can signify knee osteoarthritis progression; however, these changes are not always concurrent. A better understanding of mechanical factors associated with progression and whether they differ for structural versus clinical outcomes could lead to improved conservative management. This study examined baseline gait differences between progression and no progression groups defined at an average of 7-year follow-up using 2 different outcomes indicative of knee osteoarthritis progression: radiographic medial joint space narrowing and total knee arthroplasty. Of 49 individuals with knee osteoarthritis who underwent baseline gait analysis, 32 progressed and 17 did not progress using the radiographic outcome, while 13 progressed and 36 did not progress using the arthroplasty outcome. Key knee moment and electromyography waveform features were extracted using principal component analysis, and confidence intervals were used to examine between-group differences in these metrics. Those who progressed using the arthroplasty outcome had prolonged rectus femoris and lateral hamstrings muscle activation compared with the no arthroplasty group. Those with radiographic progression had greater mid-stance internal knee rotation moments compared with the no radiographic progression group. These results provide preliminary evidence for the role of prolonged muscle activation in total knee arthroplasty, while radiographic changes may be related to loading magnitude.

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

BACKGROUND: The present study aims to describe the imaging features in incident radiographic patellofemoral osteoarthritis (RPFOA) population in a Chinese suburban area. METHODS: The Beijing Shunyi osteoarthritis (BJS) study was a population-based, longitudinal and prospective study. Residents were recruited by randomized cluster sampling in 2014 and were followed 3 years later. Home interviews and clinical examinations were performed; weight-bearing posterior-anterior semi-flexed (45-degree) views of the tibiofemoral (TF) joints and skyline (45-degree) views of the patellofemoral (PF) joints were included. For each batch of study films (n = 100), 20 films from the year 2014 and 20 previously read PF radiographs were fed back to test inter-/intra-reader repeatability. The imaging features of incident RPFOA were analyzed. Narrative statistics, independent-sample t-tests, and nonparametric tests were performed. RESULTS: A total of 1295 participants (2590 knees) were recruited at baseline in 2014, and 967 (74.7%) residents were followed in 2017. Of all the knees (n = 1537) without RPFOA at baseline, 139 knees (13.3%) across 119 people developed incident RPFOA. Compared with the whole population, age (p = 0.031), body mass index (BMI, p = 0.042), and incidence of knee pain symptoms (p < 0.01) were significantly different in the incident RPFOA population, while range of motion (ROM, p = 0.052) and gender (0/1, p = 0.203) showed no significance. In the incident population, the changes of each imaging indicator grade were evaluated-lateral patellofemoral osteophyte (LPOST, increased by 1.02), medial patellofemoral osteophyte (MPOST, increased by 0.49), lateral joint space narrowing (LJSN, increased by 0.30), medial joint space narrowing (MJSN, increased by 0.06); indicator grade progress decreases, respectively. The progress of LPOST was the fastest among the four indicators (p < 0.01). CONCLUSIONS: In this population-based longitudinal study, among the incident RPFOA population, the imaging indicators show that marginal patellofemoral osteophyte is more pronounced than patellofemoral joint space narrowing. LPOST is the fastest-progressing indicator among all the radiographic features, which is also the most common imaging manifestation of RPFOA. In the incident RPFOA population, the proportion of elders, women, higher-BMI individuals, and people suffering knee pain is more than the normal population.

Association between thigh muscle strength four years after partial meniscectomy and radiographic features of osteoarthritis 11 years later.

BACKGROUND: Meniscus injury and meniscectomy both entail increased risk of knee osteoarthritis (OA). Thigh muscle weakness is a suggested mediator of OA but there is little evidence of its importance for knee OA development after meniscectomy. This study aimed to examine the association between thigh muscle strength after partial meniscectomy in middle-aged subjects with a non-traumatic meniscal tear and later radiographic knee OA changes. METHODS: Thirty-four out of 45 participants in an exercise-trial underwent testing for isokinetic thigh muscle strength 4 years after arthroscopic partial meniscectomy and had radiographic examination 11 years later (15 years post-surgery, mean age at follow-up of 57 years (range 50-61)). Outcomes were grade of joint space narrowing and osteophyte score in the medial tibiofemoral compartment of the operated knee and the contralateral knee. We tested the association between muscle strength at baseline and the radiographic outcomes at follow-up using logistic regression analyses adjusted for sex and overweight. RESULTS: At follow-up, 33/34 subjects had joint space narrowing and 27/34 subjects had osteophytes in the operated knee, in the contralateral knee joint space narrowing was found in 23 subjects. In the operated knee baseline knee extensor and flexor strength were negatively associated with grade of joint space narrowing at follow-up (OR 0.972 and 0.956, p = 0.028 and 0.026, respectively) and also with osteophyte score (OR 0.968 and 0.931, p = 0.017 and 0.011, respectively). In the contralateral knee longitudinal associations between strength and radiographic OA features were similar, OR 0.949-0.972, p < 0.05. CONCLUSION: The finding that stronger thigh muscles 4 years after meniscectomy were associated with less severe osteoarthritic changes in the medial tibiofemoral compartment of both the operated and contralateral knee 11 years later, may suggest that strong thigh muscles can help to preserve joint integrity in middle-aged subjects at risk of knee OA.

Patient satisfaction after total knee arthroplasty is better in patients with pre-operative complete joint space collapse.

AIM OF THE STUDY: To determine if pre-operative radiologic minimal joint space width (mJSW) is related to the outcome of total knee arthroplasty (TKA) (primary hypothesis). Likewise, the aim was to test if pre-operative mJSW is related to prosthesis survival (secondary hypothesis). METHODS: A retrospective comparative analysis was performed. Group 1 was comprised of patients with pre-operative mJSW 0-1 mm. Group 2 were patients with pre-operative mJSW ≥ 2 mm. The clinical outcome was determined with the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) score pre-operatively and one year after TKA. Only patients with pre-operative weight-bearing radiographs and complete WOMAC score data were accepted. RESULTS: Available for analysis were 377 patients, of whom 188 were allocated to Group 1 (118 female, 70 male, age 70 ± 11 years) and 189 to Group 2 (118 female, 71 male, age 70 ± 13 years). Pre-operative WOMAC total and WOMAC subscores showed no significant differences between groups. Post-operatively, the WOMAC total was significantly better in Group 1 than in Group 2, 10 ± 22 and 19 ± 31, respectively (p < 0.001, Power 97.5%). Similarly, the WOMAC subscores for pain, stiffness, and function were also significantly better in Group 1 than in Group 2. Five-year prosthesis survival was 94.2 and 91.6% in Groups 1 and 2, respectively (p = 0.07, Power 71%). DISCUSSION: Patients with pre-operative complete joint space collapse (0 to 1 mm mJSW) achieve a significantly better WOMAC result from TKA than do those with a mJSW equal to or greater than 2 mm. From our findings, it is recommended that "complete joint space collapse" especially be used as an indication for TKA surgery. CONCLUSION: Our study was underpowered to sufficiently show an effect of pre-operative mJSW on prosthesis survival.

Unipodal stance influences radiographic evaluation of foot balance in horses.

Lifting the contralateral forelimb (unipodal stance) is often used as a method of restraint in horses. This experimental one group pretest, posttest study was conducted to evaluate the effects of unipodal stance on quantitative radiographic parameters in equine forefeet. Seven nonlame horses were randomly selected. Lateromedial (LM) and dorsopalmar (DP) projections were acquired for both forefeet, squarely placed on blocks, using two X-ray generators. Radiographs of each foot were acquired first in a bipodal stance, immediately followed by the same radiographic projections obtained in a unipodal stance. The following measurements were recorded for each stance: distal interphalangeal joint (DIPJ) space width on both projections; mediolateral joint balance as the difference between lateral and medial DIPJ space widths on DP projections; extensor process-to-middle phalangeal condyle distance; and deep digital flexor tendon angle on LM projections. A matched pairs design and Student's t-test with a 95% confidence level were used to test for statistical significance. Compared to a bipodal stance, lateral DIPJ space width was significantly reduced on unipodal DP views, whereas mediolateral joint imbalance and to a lesser extent medial DIPJ space width were significantly increased. On unipodal LM views, there was a significant higher degree of DIPJ flexion. These findings suggest that stance should be carefully taken into consideration when measuring radiographic parameters in equine forefeet, especially if assessing foot balance and conformation, as unipodal stance significantly affects the mediolateral balance of the DIPJ on DP radiographs and significantly alters the phalangeal axis on LM radiographs.

A quantitative metric for knee osteoarthritis: reference values of joint space loss.

OBJECTIVES: Knee osteoarthritis (OA) onset and progression has been defined with transitions in Kellgren-Lawrence (KL) grade or Osteoarthritis Research Society International (OARSI) Joint Space Narrowing (JSN) grade. We quantitatively describe one-year transitions in KL grade and JSN, using fixed joint space width (fJSW), among knees with or at risk of OA. METHODS: Radiographic assessments from the Osteoarthritis Initiative (OAI) were used to identify transitions in KLG and JSN grade between consecutive annual visits. The fJSW was measured in the medial and lateral compartments. The distribution of change in fJSW for KLG and JSN transitions were described, and mean change in fJSW was estimated using mixed models. RESULTS: KL grade and JSN scores were available for about 20,000 annual transitions from 6047 knees contributed by 3389 participants. Knees that remained stable in KL or OARSI-JSN over 1 year had mean medial fJSW loss between -0.06 and -0.19 mm/year. Transition from KL grade 0 to 1, 0 to 2, and KL 1 to 2 were similar with respect to mean medial fJSW loss (0.18-0.28 mm). Greatest annual changes in medial fJSW corresponded to KL 0 to 3 (1.62 mm), KL 2 to 4 (1.23 mm) and JSN 0 to 2 (1.85 mm). CONCLUSIONS: Anchoring quantitatively measured loss of joint space width to transitions in KL grade and JSN provides reference values based on traditional definitions of knee OA onset and progression.