Joint Space Width Research Articles

Does Irreducibility Always Mean a Complex Dislocation? An Analysis of 33 Pediatric Metacarpophalangeal Joint Dislocations.

Previous failed reduction and certain radiographic indicators historically have been used to differentiate simple and complex metacarpophalangeal joint (MPJ) dislocations in children, the latter of which warrants open reduction. This investigation aimed to determine the necessity for open reduction with these indicators and establish a new treatment algorithm and educational focus for these rare injuries. A 12-year retrospective study was conducted on all children with MPJ dislocations at a single pediatric hospital. The rates of successful closed reduction, number of reduction attempts, and radiographic findings were detailed. Operative details and postoperative outcomes were also gathered. Thirty-three patients with a mean age of 11.1 years were included. Most were male [ n = 27 (82%)] and had undergone two or more previous reduction attempts at an outside facility. Stable closed reduction was then achieved outside of the operating room in five patients and in the operating room under general anesthesia in another 14, for a total of 19 of 33 patients (57.6%). The thumb was injured most often [ n = 19 (57.6%)] and more likely to undergo successful closed reduction ( P = 0.04). There was no relationship between number of previous reduction attempts and ability to achieve closed reduction ( P = 0.72). Neither joint-space widening nor proximal phalanx bayonetting was correlated radiographically with failure of closed reduction ( P = 0.22 and P = 1, respectively). This study supports closed reduction of pediatric MPJ dislocations in the operating room under general anesthesia before conversion to open reduction, regardless of injury characteristics or previous reduction attempts. This strategy is likely to limit unnecessary open surgery and related risks. Risk, IV.

Distraction Gap Needed for Safe Central Compartment Access in Hip Arthroscopy

Background: Sufficient distraction of the hip is the key to a safe central compartment (CC) approach in hip arthroscopy. However, an adequate distraction gap has not been scientifically identified. Purpose: To determine the sufficient amount of distraction that could predict a successful CC access as well as to identify the risk factors for a failed or difficult CC access. Study Design: Case-control study; Level of evidence, 3. Methods: All patients who underwent hip arthroscopy by a single surgeon between January 2018 and April 2019 were prospectively enrolled. We analyzed gaps of the hip on 4 C-arm fluoroscopic images: nondistraction, preoperative manual traction, preoperative maximal traction (without distension), and intraoperative maximal traction (at the end of CC procedures in a successful CC approach or after peripheral compartment procedures in a failed or difficult CC approach). A failed CC approach was defined as failure in introducing the anterolateral portal to the CC under arthroscopic control; a difficult CC approach was defined as the presence of an incomplete diagnostic round in the CC because of a small distraction. The amount of distraction was evaluated by the ratio of the distracted gap to the undistracted gap. Patients were classified into the successful CC access group (group 1) and the failed/difficult CC access group (group 2). The amount of distraction, demographic characteristics, and preoperative radiographic parameters were compared between the groups. Results: A total of 240 patients were included in this study. Group 1 consisted of 205 patients (113 males and 92 females; mean ± SD age, 34.5 ± 11.4 years), and group 2 consisted of 35 patients (27 males and 8 females; age, 32.5 ± 11.2 years). The preoperative joint space width was not significantly different between group 1 (mean ± SD, 3.89 ± 0.83 mm) and group 2 (3.68 ± 0.68 mm). The ratio of the amount of distraction at lateral gaps under all traction conditions was significantly greater in group 1 compared with group 2 (1.50 ± 0.54 vs 1.26 ± 0.35, respectively, under preoperative manual traction; 2.84 ± 0.76 vs 2.03 ± 0.63 under preoperative maximal traction; 3.36 ± 0.96 vs 2.50 ± 0.79 under intraoperative maximal traction). An increase of the lateral gap by >2.2 times (P < .001) under preoperative maximal traction and by >2.7 times (P < .001) under intraoperative maximal traction could predict successful CC access. Male sex (odds ratio [OR], 2.94; P = .017) and increased lateral center-edge angle (OR, 1.08 for every 1° increase; P = .004) were significant risk factors for failed/difficult CC access. Conclusion: An increase of the lateral gap by >2.2 times during an unsterile traction test without joint distension could predict successful CC access. Male sex and increased lateral center-edge angle were risk factors for a failed or difficult CC access.

Biomechanical effect of fibular osteotomy on the knee joint in high tibial osteotomy: A cadaveric study.

Closed-wedge high tibial osteotomy (CWHTO) with a fibular osteotomy (FO) causes medial joint space widening in the knee. However, the effect of FO on the joint space width remains unclear. This study aimed to examine the effect of FO on the knee in HTO. A compression load test was performed on two amputated human limbs under four conditions: (1) normal (without any osteotomy), (2) open-wedge HTO (OWHTO), (3) OWHTO with FO, and (4) CWHTO. The contact area of the femoral and tibial cartilages and the medial and lateral joint space widths in each condition were evaluated using a motion capture system with computed tomography (CT) and magnetic resonance imaging (MRI) data. The contact area increased on the lateral side after OWHTO, which increased more on the lateral side with a concomitant decrease on the medial side in both subjects when FO was added to OWHTO. An increase in the medial joint space width and a decrease on the lateral side were seen in both OWHTO with FO and CWHTO. The contact area and joint space widths are affected by the FO, and the effect is more pronounced than the way of HTO (OWHTO or CWHTO).

Automatic measuring of finger joint space width on hand radiograph using deep learning and conventional computer vision methods

Hand osteoarthritis (OA) severity can be assessed visually through radiographs using semi-quantitative grading systems. However, these grading systems are subjective and cannot distinguish minor differences. Joint space width (JSW) compensates for these disadvantages, as it quantifies the severity of OA by accurately measuring the distances between joint bones. Current methods used to assess JSW require users’ interaction to identify the joints and delineate the initial joint boundary, which is time-consuming. To automate this process and offer a robust measurement for JSW, we proposed two novel methods to measure JSW: (1) The segmentation-based (SEG) method, which uses traditional computer vision techniques to calculate JSW; (2) The regression-based (REG) method, which is a deep learning approach employing a modified VGG-19 network to predict JSW. On a dataset with 3591 hand radiographs, 10,845 DIP joints were cut as ROI and served as input to the SEG and REG methods. The bone masks of the ROI images generated by a U-Net model were sent as input in addition to the ROIs. The ground truth of JSW was labeled by a trained research assistant using a semi-automatic tool. Compared with the ground truth, the REG method achieved a correlation coefficient (r) of 0.88 and a mean square error (MSE) of 0.02 mm on the testing set; the SEG method achieved a correlation coefficient of 0.42 and an MSE of 0.15 mm. Results show the REG method has promising performance in JSW measurement and, in general, Deep Learning approaches can facilitate the automatic quantification of distance features in medical images.

Quantitative morphometric analysis in tibiofemoral joint osteoarthritis imaging: A literature review

ObjectiveTo highlight published quantitative morphometric analysis (QMA) methods for assessing tibiofemoral joint osteoarthritis in magnetic resonance imaging and computed tomography and underline the need for open and interoperable protocols for quantitative image analysis. DesignA literature search on PubMed/MEDLINE and Web of Science of keywords relating to QMA in magnetic resonance imaging and computed tomography in the context of tibiofemoral osteoarthritis in the past 23 years (2000–2022). The search was based on, but not limited to: “quantitative morphometric analysis” or “quantitative image analysis” in combination with “osteoarthritis”, “articular cartilage”, “subchondral bone”, “tibiofemoral joint”, “joint”, “CT”, and “MRI”. The search found 73 relevant publications that were manually screened and sorted for QMA methods. A further search to extract key functions of the underlying algorithms was performed. ResultMRI is generally used for QMA of articular cartilage and joint contact area, while CT is generally used for QMA of subchondral bone and joint space width. Studies have shown that QMA algorithms can be adapted to new tissues and modalities. However, many methods are not easily accessible, and there is fragmentation of computational tools and platforms in the research field. ConclusionQMA is an active research area, and many techniques from one modality can be readily extended to another. Adoption of open-source practices can allow algorithms developed for other imaging modalities to be shared, making it possible to bridge the knowledge gap for structures and pathological features for which QMA has not yet been investigated and to increase research output overall.

Analysis of the determinant factor of the medial joint space width after medial opening wedge high tibial osteotomy.

The decrease in the medial joint space width (MJSW) in patients with osteoarthritis (OA) is proportional to the degree of arthritis. The purpose of this study was to evaluate the affecting factors of the MJSW by serial radiologic assessment after medial open wedge high tibial osteotomy (MOW-HTO). Between March 2014 and March 2019, 162 MOW-HTO knees that underwent serial radiologic assessment and follow-up MRI were enrolled. Changes in the MJSW were analyzed by dividing into three groups: group I, low quartile (< 25%); II, middle quartile (25-75%); and III, high quartile (> 75%), according to the magnitude of the MJSW. The correlation between the MJSW and weight-bearing line ratio (WBLR), hip knee ankle angle (HKA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle (m-LDFA), joint line orientation angle (JLOA), and MRI cartilage status was analyzed. Multiple linear regression analysis was used to analyze factors affecting the amount of change in the MJSW. The clinical outcome was also correlated with the MJSW. The amount of change in the JLCA, which has the largest beta value (weight-bearing standing anteroposterior (AP) view and 45° flexion posteroanterior view (Rosenberg view) β = - 0.699 and β = -5.221, both p < 0.001, respectively), had the greatest contribution to the change in the MJSW. The WBLR was also related (standing AP and Rosenberg β = 0.177 and β = 0.264, p = 0.015 and p = 0.004, respectively). There was no statistical difference between the amount of change in the MJSW and the change in cartilage. The clinical outcomes did not differ between the groups. The JLCA was the most important contributing factor for the MJSW, followed by WBLR. This contribution was more pronounced in Rosenberg view than standing AP view. Changes in cartilage status were not related to the MJSW and JLCA. The clinical outcome was not related to the MJSW, either. Level of evidence Cohort study; level III.

Association of physical activity with loss of knee joint space width over two years: a compositional data analysis in the Osteoarthritis Initiative

There is continued debate as to how engaging in physical activity (PA), including moderate-to-vigorous PA (MVPA), light PA (LPA), and sedentary time (SED), affects one's risk for knee osteoarthritis (OA). Traditional regression methods do not account for the codependence of these categories of PA, whereby when one category increases, the others must decrease. Thus, we used compositional data analysis (CoDA) to examine time spent in each category of PA, or PA composition, and its association with loss of knee joint space width (JSW), a common indicator of knee OA progression. We performed a secondary analysis of data from a subset of participants in the Osteoarthritis Initiative. These participants had minute-by-minute activity data collected over 7 days at baseline; we then categorized each minute as MVPA, LPA, or SED. Our exposure, PA composition, represented min/day spent in each category. Our outcome, medial JSW loss, was the difference in medial tibiofemoral JSW from baseline to 2years later. We employed CoDA, using an isometric log-ratio transformation, to examine the association of PA composition with medial JSW loss over 2years, adjusting for potential confounders. We included 969 participants (age: 64.5 years, 56% female, body mass index [BMI]: 28.8kg/m2). Mean PA composition was: MVPA 9.1min/day, LPA 278min/day, SED 690min/day. Per adjusted regression models, higher MVPA was not associated with greater medial JSW loss (β=-0.0005, P=0.97), nor was LPA (β=0.06, P=0.27) or SED (β=-0.06, P=0.21). Using CoDA, PA composition was not associated with medial JSW loss over 2years.

Graft Extrusion of 3 Millimeters Is Acceptable at a Minimum of 5-Year Outcomes for Lateral Meniscal Allograft Transplantation

To determine the acceptable amount of graft extrusion based on long-term radiographic outcomes in lateral meniscal allograft transplantation (MAT). 94 lateral MAT patients with a minimum 5-year follow-up period were reviewed. Graft extrusion was measured on MRI scans taken 1 year after surgery, and the study population was divided according to the amount of extrusion: group A, extrusion <3 mm; group B, 3 mm ≤ extrusion <5 mm; and group C, extrusion ≥5 mm. For radiographic evaluation, the bilateral lateral joint space widths (JSWs) were measured on a standing 45° flexion posteroanterior radiograph. To standardize the measurements, the affected JSW was divided by the contralateral JSW. The change in the standardized JSW (ΔJSWstd) between the preoperative and latest follow-up assessments was analyzed according to the three groups. Multiple regression analysis was performed to control other related factors, such as lower limb alignment and cartilage status at the time of MAT. The acceptable amount of graft extrusion was calculated using a receiver operating characteristic (ROC) curve for the third quartile of ΔJSWstd. Clinical outcomes were evaluated using the Lysholm score and were compared among the groups. The mean follow-up duration was 8.3 ± 3.1 years. There were 54, 25, and 15 patients in group A, group B, and group C, respectively. In multiple regression analysis, both group B and group C had significant associations with ΔJSWstd and their beta coefficients were comparable (group B, P < .001, β= .642; group C, P < .001, β= 0.613). No significant difference in ΔJSWstd was found between group B and group C (P= .494). On the basis of the ROC curve, the acceptable amount of graft extrusion was 3.74 mm (sensitivity, 81.8%; specificity, 77.8%). There were no differences in the Lysholm scores among the three groups (P= .329). ΔJSWstd differed between graft extrusion <3 mm (group A) and graft extrusion ≥3 mm (group B and group C). However, there was no significant difference in ΔJSWstd between group B and group C. No significant difference in clinical outcomes was found according to graft extrusion. This study gave supporting evidence for the currently recognized acceptable amount of graft extrusion (3 mm). Level III, retrospective cohort study.

Analysis of Hand Joint Space Morphology in Women and Men with Hereditary Hemochromatosis

Hereditary hemochromatosis (HH) causes unbalanced iron deposition in many organs including the joints leading to severe cartilage loss and bone damage in the metacarpophalangeal joints (MCPJ). High-resolution peripheral quantitative computed tomography (HR-pQCT) and its joint space width (JSW) quantification algorithm quantifies in vivo 3D joint morphology. We therefore aimed to (i) determine feasibility and performance of the JSW algorithm in HH, (ii) quantify joint space morphology, and (iii) investigate the relationship between morphological and clinical parameters in HH. Here, we performed an exploratory study on 24 HH patients and sex- and age-matched controls using HR-pQCT imaging of MCPJ. Mineralized bone structure was automatically segmented from the grayscale image data and periosteal surface bone masks and joint space masks were generated. Mean, minimal, and maximal joint space width (JSW; JSW.MIN; JSW.MAX), JSW heterogeneity (JSW.SD), JSW asymmetry (JSW.AS), and joint space volume (JSV) were computed. Demographics and, for HH patients, disease-specific parameters were recorded. Segmentation of JS was very good with 79.7% of MCPJs successfully segmented at first attempt and 20.3% requiring semi-manual correction. HH men showed larger JSV at all MCPs (+ 25.4% < JSV < + 41.8%, p < 0.05), larger JSW.MAX at MCP 3-4 (+ 14%, 0.006 < p < 0.062), and wider JSW (+ 13%, p = 0.043) at MCP 4 relative to HH women. Compared to controls, both HH men and HH women showed larger JSW.AS and smaller JSW.MIN at all MCP levels, reaching significance for HH men at MCP 2 and 3 (JSW.AS: + 323% < JSW.AS < + 359%, 0.020 < p < 0.043; JSW.MIN: − 216% < JSW.MIN < − 225%, p < 0.043), and for women at MCP 3 (JSW.AS: + 180%, p = 0.025; JSW.MIN: − 41.8%, p = 0.022). Time since HH diagnosis was correlated positively with MCP 4 JSW.AS and JSW.SD (0.463 < ρ < 0.499, p < 0.040), and the number of phlebotomies since diagnosis was correlated with JSW.SD at all MCPs (0.432 < ρ < 0.535, p < 0.050). HR-pQCT-based JSW quantification in MCPJ of HH patients is feasible, performs well even in narrow JS, and allows to define the microstructural joint burden of HH.

Correlation between Bone Mineral Density and Progression of Hip Osteoarthritis in Adult Men and Women in Bulgaria—Results from a 7-Year Study

Changes in clinical presentation, radiographic progression (RP), bone mineral density (BMD), bone turnover (BT), and cartilage turnover (CT) markers were compared in two groups of patients with hip osteoarthritis (HOA) over a period of 7 years. Each group consisted of 150 patients, including a control group on standard-of-care therapy (SC) with simple analgesics and physical exercises, and a study group (SG) on standard-of-care therapy supplemented by vitamin D3 and intravenous administration of zoledronic acid (5 mg) yearly for 3 consecutive years. Patient groups were homogenized regarding the following: (1) radiographic grade (RG), including 75 patients with hip OA RG II according to the Kellgren-Lawrence grading system (K/L), and 75 with RG III on K/L; (2) radiographic model (RM), as each of the K/L grades was subdivided into three subgroups consisting of 25 patients of different RMs: atrophic ('A'), intermediate ('I'), and hypertrophic ('H'); (3) gender-equal ratio of men and women in each subgroup (Female/Male = 15/10). The following parameters were assessed: (1) clinical parameters (CP), pain at walking (WP-VAS 100 mm), functional ability (WOMAC-C), and time to total hip replacement (tTHR); (2) radiographic indicators(RI)-joint space width (JSW) and speed of joint space narrowing (JSN), changes in BMD (DXA), including proximal femur (PF-BMD), lumbar spine (LS-BMD), and total body (TB-BMD); (3) laboratory parameters (LP)-vitamin D3 levels and levels of BT/CT markers. RV were assessed every 12 months, whereas CV/LV were assessed every 6 months. Results: Cross-sectional analysis (CsA) at baseline showed statistically significant differences (SSD) at p < 0.05 in CP (WP, WOMAC-C); BMD of all sites and levels of CT/BT markers between the 'A' and 'H' RM groups in all patients. Longitudinal analysis (LtA) showed SSD (p < 0.05) between CG and SG in all CP (WP, WOMAC-C, tTHR) parameters of RP (mJSW, JSN), BMD of all sites, and levels of CT/BT markers for all 'A' models and in 30% of 'I'-RMs (those with elevated markers for BT/CT at baseline and during the observation period). Conclusion: The presence of SSD at baseline ('A' vs. 'H') supported the thesis that at least two different subgroups of HOA exist: one associated with 'A' and the other with 'H' models. D3 supplementation and the intravenous administration of bisphosphonate were the treatment strategies that slowed down RP and postponed tTHR by over 12 months in the 'A' and 'I' RM with elevated BT/CT markers.

Comparison of 3D quantitative osteoarthritis imaging biomarkers from paired CT and MR images: data from the IMI-APPROACH study

IntroductionMRI bone surface area and femoral bone shape (B-score) measures have been employed as quantitative endpoints in DMOAD clinical trials. Computerized Tomography (CT) imaging is more commonly used for 3D visualization of bony anatomy due to its high bone-soft tissue contrast. We aimed to compare CT and MRI assessments of 3D imaging biomarkers.MethodsWe used baseline and 24-month image data from the IMI-APPROACH 2-year prospective cohort study. Femur and tibia were automatically segmented using active appearance models, a machine-learning method, to measure 3D bone shape, area and 3D joint space width (3DJSW). Linear regression was used to test for correlation between measures. Limits of agreement and bias were tested using Bland-Altman analysis.ResultsCT-MR pairs of the same knee were available from 434 participants (78% female). B-scores from CT and MR were strongly correlated (CCC = 0.967) with minimal bias of 0.1 (SDD = 0.227). Area measures were also correlated but showed a consistent bias (MR smaller). 3DJSW showed different biases (MR larger) in both lateral and medial compartments.DiscussionThe strong correlation and small B-score bias suggests that B-score may be measured reliably using either modality. It is likely that the bone surface identified using MR and CT will be at slightly different positions within the bone/cartilage boundary. The negative bone area bias suggests the MR bone boundary is inside the CT boundary producing smaller areas for MR, consistent with the positive 3DJSW bias. The lateral-medial 3DJSW difference is possibly due to a difference in knee pose during acquisition (extended for CT, flexed for MR).Trial registrationNCT03883568

Joint distraction for the treatment of knee osteoarthritis

Knee osteoarthritis (OA) is a common degenerative joint disease characterized by cartilage destruction and changes in subchondral bone. Treatment options for end-stage OA are limited, with joint replacement and high tibial osteotomy as the common procedures. High tibial osteotomy may be preferable to joint replacement in the young active patient, malaligned knee, and limited to medial compartment OA. However, both procedures may lead to complications and have durability concerns in young patients. Fortunately, joint distraction (JD) has emerged as a joint-preserving treatment for end-stage OA. The reversal of tissue degeneration observed with JD could be the result of one or more proposed mechanisms, such as partial unloading, synovial fluid pressure oscillation, mechanical and biochemical changes in subchondral bone, or adhesion and chondrogenic commitment of joint-derived mesenchymal stem cells. The procedure involves the use of an external fixator to unload the cartilage and underlying bone for a short time period. In addition, new implantable knee devices, which create unloading instead of distraction and do not require removal, have also been developed. There is a lack of standardization for the JD technique which results in significant variation of implant type, duration of treatment, and rehabilitation. Nevertheless, clinical studies demonstrate long-term pain relief and improved patient outcomes. Interestingly, the increase in joint space width following treatment indicates that cartilage repair occurred throughout and after the distraction period. Although JD appears to be an effective therapeutic choice, the rate of complications remains high, with pin-tract infection being the most common.

Mid-Term Clinical and Radiological Outcomes of Lateral Meniscal Allograft Transplantation with Suture-Only Fixation Plus Capsulodesis.

Meniscal allograft transplantation (MAT) is an effective reconstructive procedure for treating a symptomatic postmeniscectomy syndrome. It consists of replacing the lost meniscal tissue aiming to improve the clinical outcomes and prevent progressive deterioration of the joint. The aim of this study was to evaluate meniscal graft survivorship and report on the radiographic (in terms of graft extrusion and joint space width and alignment) and the functional results through a midterm follow-up of lateral MAT performed with a soft tissue fixation technique after capsulodesis. In total, 23 patients who underwent lateral MAT as a single procedure were included. The Knee injury and Osteoarthritis Outcome Score, Lysholm, Tegner, and visual analog scale scales were used for patient assessment. Magnetic resonance imaging and a complete radiographic protocol were conducted to determine the degree of meniscal extrusion and the changes in the degree of osteoarthritis and coronal alignment. Assessments were performed after 2 and 7 years of follow-up. A significant improvement in all the scores, relative to preoperative values, was found after 7 years of follow-up. This improvement remained consistent throughout the first and second follow-up periods. A mean absolute extrusion of 2.2 mm ± 1.6 and an extrusion percentage of 28.0% ± 11.43 were found, with no significant differences throughout the follow-up periods. There was no statistically significant difference in terms of the frontal mechanical axis and joint space narrowing between the preoperative value and at the first and second follow-up periods. A survival rate of 85.7% was found after 7 years of follow-up. Capsulodesis results in a low degree of meniscal extrusion in isolated lateral MAT fixed with a suture-only technique, which is maintained after 7 years of follow-up, with a high graft survival index (>85%) and satisfactory results on the functional scales.

Exploring the differences between radiographic joint space width and MRI cartilage thickness changes using data from the IMI-APPROACH cohort.

Longitudinal weight-bearing radiographic joint space width (JSW) and non-weight-bearing MRI-based cartilage thickness changes often show weak correlations. The current objective was to investigate these correlations, and to explore the influence of different factors that could contribute to longitudinal differences between the two methods. The current study included 178 participants with medial osteoarthritis (OA) out of the 297 knee OA participants enrolled in the IMI-APPROACH cohort. Changes over 2years in medial JSW (ΔJSWmed), minimum JSW (ΔJSWmin), and medial femorotibial cartilage thickness (ΔMFTC) were assessed using linear regression, using measurements from radiographs and MRI acquired at baseline, 6months, and 1 and 2years. Pearson R correlations were calculated. The influence of cartilage quality (T2 mapping), meniscal extrusion (MOAKS scoring), potential pain-induced unloading (difference in knee-specific pain scores), and increased loading (BMI) on the correlations was analyzed by dividing participants in groups based on each factor separately, and comparing correlations (slope and strength) between groups using linear regression models. Correlations between ΔMFTC and ΔJSWmed and ΔJSWmin were statistically significant (p < 0.004) but weak (R < 0.35). Correlations were significantly different between groups based on cartilage quality and on meniscal extrusion: only patients with the lowest T2 values and with meniscal extrusion showed significant moderate correlations. Pain-induced unloading or BMI-induced loading did not influence correlations. While the amount of loading does not seem to make a difference, weight-bearing radiographic JSW changes are a better reflection of non-weight-bearing MRI cartilage thickness changes in knees with higher quality cartilage and with meniscal extrusion.

WEIGHT BEARING 3-D JOINT SPACE WIDTH DISTRIBUTION AT THE KNEE VARIES ACCORDING TO LOCATION AND EXTENT OF MENISCAL EXTRUSION: A MOST INVESTIGATION

Quantitative 3-D measurement of joint space width (JSW) from weight bearing computed tomography (WBCT) allows analysis of knee tibiofemoral compartments in a loaded stance without subregional constraints on analysis. The relationship between 3-D JSW distribution and meniscal extrusion is yet to be established. To demonstrate topographic variations in 3-D JSW distribution at the knee derived from WBCT imaging data according to meniscal extrusion location and extent. WBCT knee imaging was acquired at the 144-month visit of the Multicenter Osteoarthritis Study (MOST). A subset of individuals had medial and lateral meniscal extrusion grading according to the MRI Osteoarthritis Knee Score to identify medial extrusion of the medial meniscus (MMmed), anterior extrusion of the medial meniscus (MMant), anterior extrusion of the lateral meniscus (LMant), and lateral extrusion of the lateral meniscus (LMlat). The extent of extrusion was graded as 0: <2 mm; 1: 2 to 2.9 mm, 2: 3 to 4.9 mm; and 3: >5 mm. After semi-automatic segmentation of 663 baseline knees, joint space mapping was performed to create 3-D JSW maps for each knee registered to a template surface. Statistical parametric mapping (SPM) was performed using a general linear model to test the dependence of 3-D JSW distribution on each of meniscal extrusion type in turn. SPM results were plotted on the canonical joint surface, with unmasked regions demonstrating the topographic difference in JSW for each increment in extrusion score. 568 knees from 330 participants had meniscal extrusion grading available. Participants (178 female) had mean ± SD age 62.0 ± 9.3 years, body mass 82.2 ± 17.4 kg, height 170 ± 9.5 cm, and BMI 28.3 ± 4.8 kg/m2. Analysed knees were bilateral for 238 participants and unilateral for 92 participants. For MMmed (cohort score range 0-3), the central-to-posterior medial compartment had significantly lower JSW by up to 0.4 mm for each increment in meniscal extrusion grade. Both MMmed and MMant (score range 0-3) were associated with a small region of similarly significantly lower JSW along the medial margin of the lateral compartment, but also with significantly greater JSW at the anterior medial compartment of up to 0.6 mm per grade. The posterior medial joint space was significantly narrower (up to 3 mm) comparing knees with LMant scores of 0 vs 1. This same magnitude of narrowed JSW was detected along the periphery of the lateral joint space comparing grades in the lateral tibiofemoral compartment, but this was not statistically significant. LMlat (score range 0-2) was associated with a trend for greater reduction in JSW in the central lateral compartment of up to 0.5 mm per grade, but this was not statistically significant. Direction of meniscal extrusion is represented by the black arrowhead in the figure. Both medial and anterior extrusion of the medial meniscus are associated with significant reduction in JSW at the medial margin of the lateral joint space and widening of the anterior margin, likely from a posteromedial shift of the femoral condyles with respect to the tibia. Medial extrusion of the medial meniscus is also associated with narrowed JSW in the central to posterior medial joint space, likely as a direct effect of the loss of meniscal hoop tension. Anterior (but not lateral) extrusion of the lateral meniscus is associated with significantly lower JSW in the posterior medial joint space. These findings confirm that the extent and location of meniscal extrusion are key factors in weight bearing 3-D JSW distribution.

COMPUTED TOMOGRAPHY OSTEOARTHRITIS KNEE SCORE (COAKS) CONSTRUCTION, REPRODUCIBILITY AND POTENTIAL FOR STRUCTURAL PHENOTYPING

Computed tomography (CT) has been shown to be more sensitive identifying certain structural features of OA than radiography and MRI. The ability to acquire weight bearing CT (WBCT) at the knee is also an important current advantage over MRI that has created an opportunity to assess the entire weight bearing joint in 3-D. This could have implications for longitudinal monitoring of disease progression and the selection of participants in clinical trials according to structural phenotype. 1) To introduce the semi-quantitative CT OA Knee Score (COAKS); 2) to report initial interobserver reproducibility; and 3) to demonstrate its potential for structural disease phenotyping. 106 WBCT examinations were sourced from existing research projects at the Department of Rehabilitation Medicine, University of Kansas Medical Center, USA. A 4-point scoring system (0-3) was created for each cardinal radiographic feature of osteoarthritis (J = joint space width; O = osteophytes; C = subchondral cysts; S = subchondral sclerosis) to be assessed at each joint compartment (MTF = medial tibiofemoral; LTF = lateral tibiofemoral; PF = patellofemoral; PTF = proximal tibiofibular). Brief verbal definitions are given for each feature score in table 1. After initial training and grading of all knees by a musculoskeletal radiology clinical fellow (J.J.H.), a reference atlas was created that included a standardised review guide (including display settings and multiplanar reformat orientations), examples of each score for each feature at each compartment, and common pitfalls. Blinded to the imaging data, 10 test knees and 35 study knees were super-selected by their initial scoring to stratify disease features as evenly as possible. No restrictions were placed on the quality of imaging, the presence of ACL reconstruction (an inclusion criteria for one source study), or imaging review platform. T.D.T. trained another consultant musculoskeletal radiologist (Z.A.), who both assessed the 10 test knees, reviewed performance, then repeated the test assessment. Both then scored the 35 study knees without communication during the assessment period. A cloud score sheet was used in Google Sheets (table 2) with the reference atlas in Google Docs, both accessible online or via the respective smart phone / tablet app. The weighted kappa score for interobserver reproducibility was calculated for each structural feature across all compartments. Compartment feature scores were also plotted as heat maps for each knee to provide a visualisation of structural OA phenotype. The weighted kappa scores (+95% CI) for each feature were: J = 0.87 (0.86-0.89); O = 0.79 (0.76-0.82); C = 0.66 (0.63-0.70); S = 0.84 (0.82-0.86). On average, it took less than 5 minutes to score a single knee. Selected heat maps (figure 1) show how different phenotypes can be ascertained using the COAKS system: RUNA053L is an early MTF phenotype with PF involvement; RUNA045R is a late MTF phenotype with multicompartment disease; RUNA023L is a late LTF phenotype with severe multicompartmental osteophytosis but no other features; RUNA088L is a PF phenotype with small tibiofemoral osteophytes only. A whole joint COAKS score is also possible (out of 48), as is a score by compartment (out of 12) or by feature (out of 12) as desired. COAKS is a feasible semi-quantitative WBCT-based scoring system of knee OA that demonstrates initial substantial to almost perfect inter-observer agreement across radiographic features. The ability of COAKS to score and phenotype the weight bearing knee in 3-D may exceed individual capabilities of MRI and radiography in certain aspects, offering flexibility in phenotyping for patient selection as well as potential sensitivity for longitudinal monitoring of disease severity in clinical trials or cohort studies. It is also possible to use the COAKS in non-weight bearing CT if flagged as such and not used to compare with weight bearing studies.

Risk factors for the long-term incidence and progression of knee osteoarthritis in older adults: role of nonsurgical injury.

For one of the most chronic medical conditions, osteoarthritis, uncertainties remain on the impact of injury chronology, the role of repeat injury on the incidence/progression of this disease and the need for knee arthroplasty. To explore, in an older adult population, how nonsurgical knee injuries relate to osteoarthritis incidence/progression and the weight of independent risk factors for arthroplasty. A cohort study design evaluates the long-term impact of injuries on knee osteoarthritis outcomes. Knees with no prior injury (n = 6358) and with at least one injury (n = 819) ⩽20 years before study inclusion were from the Osteoarthritis Initiative cohort. Sociodemographic, clinical and structural [X-ray, magnetic resonance imaging (MRI)] data at study inclusion and changes within 96 months were analysed. Statistics included a mixed model for repeated measurements, generalized estimating equations and multivariable Cox regression with covariates. At inclusion, knees with prior injury demonstrated greater incidence and severity of osteoarthritis (p ⩽ 0.001). At 96 months, there was a greater increase in symptoms [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, p = 0.002], joint space width (JSW, p = 0.039) loss, medial cartilage volume loss (CVL, p ⩽ 0.001) and bone marrow lesion size (BML, p ⩽ 0.049). Knees with/without injury at inclusion but with new ones over time had a pronounced increase in symptoms (all WOMAC scores, p ⩽ 0.001), JSW loss, lateral (without) and medial CVL, lateral (without) and medial meniscal extrusion and medial BML (without; all p ⩽ 0.030). Levels of lateral and medial meniscal extrusion (without) and symptoms (with/without; all WOMAC scores, p ⩽ 0.001) were all accentuated with a repeated new injury. Risk factors associated with the highest knee arthroplasty occurrence are new meniscal extrusion and new injury (p ⩽ 0.001). This study highlights the importance of nonsurgical knee injury in older adults as an independent risk factor for knee osteoarthritis and arthroplasty. These data will be beneficial in clinical practice as they will help identify individuals at greater risk of significant disease progression and worst disease outcomes for a customized therapeutic approach.

Incidental findings involving the temporomandibular joint on computed tomography and magnetic resonance imaging.

The temporomandibular joint (TMJ) is frequently imaged in head and neck computed tomography (CT) and magnetic resonance imaging (MRI) studies. Depending on the indication for the study, an abnormality of the TMJ may be an incidental finding. These findings encompass both intra- and extra-articular disorders. They may also be related to local, regional or systemic conditions. Familiarity with these findings along with pertinent clinical information helps narrow the list of differential diagnoses. While definitive diagnosis may not be immediately apparent, a systematic approach contributes to improved discussions between clinicians and radiologists and better patient management.

Effect of Total Hip Arthroplasty on Ipsilateral Lower Limb Alignment and Knee Joint Space Width: Minimum 5-Year Follow-up.

This study aimed to 1) assess the effect of total hip arthroplasty (THA) on coronal limb alignment, namely, the hip-knee-ankle angle (HKA), 2) identify factors that determine changes in the HKA, and 3) determine whether alignment changes influence the knee joint space width. We retrospectively evaluated 266 limbs of patients who underwent THA. Three types of prostheses with neck shaft angles (NSAs) of 132°, 135°, and 138° were used. Several radiographic parameters were measured in the preoperative and final radiographs (at least 5 years after THA). A paired t-test was used to confirm the effect of THA on HKA change. Multiple regression analysis was performed to identify radiographic parameters related to HKA changes following THA and changes in knee joint space width. Subgroup analyses were performed to reveal the effect of NSA change on the HKA change, and the proportion of total knee arthroplasty usage and changes in radiographic parameters between maintained joint space and narrowed joint space groups were compared. The preoperative mean HKA was 1.4° varus and increased to 2.7° varus after THA. This change was related to changes in the NSA, lateral distal femoral angle, and femoral bowing angle. In particular, in the group with a decrease in NSA of > 5°, the preoperative mean HKA was largely changed from 1.4° varus to 4.6° varus after THA. The prostheses with NSA of 132° and 135° also led to greater varus HKA changes than those with an NSA of 138°. Narrowing of the medial knee joint space was related to changes in the varus direction of the HKA, decrease in NSA, increase in femoral offset. A large reduction in NSA can lead to considerable varus limb alignment after THA, which can have adverse effects on the medial compartment of the ipsilateral knee.

Relationship of early postoperative perceived leg length discrepancy to the progression of osteoarthritis in the contralateral hip after unilateral total hip arthroplasty-a retrospective cohort study using propensity score matching.

[Purpose] This study aimed to identify the relationship between the early postoperative perceived leg length discrepancy after unilateral total hip arthroplasty and the progression of osteoarthritis in the contralateral hip. [Participants and Methods] This was a retrospective cohort study of 65 patients who underwent primary unilateral total hip arthroplasty for bilateral hip osteoarthritis. The minimum joint space width of the contralateral hip was measured preoperatively. The change in minimum joint space width one year postoperatively compared with preoperatively was measured. At three weeks postoperatively, patients were divided into the perceived and non-perceived leg length discrepancy groups using the block test. Patients with a perceived leg length discrepancy of 2 mm or more and less than 2 mm were grouped into the perceived and non-perceived leg length discrepancy groups, respectively. Before and after propensity score matching, the change in minimum joint space width between the two groups from the preoperative period to one year postoperatively was compared. [Results] In the pre-propensity matching sample, there was no significant difference in the change in minimum joint space width between the two groups. In the post-propensity matching sample, the change in minimum joint space width in the perceived leg length discrepancy group was significantly larger than that in the non-perceived leg length discrepancy group. [Conclusion] The early postoperative perceived leg length discrepancy after unilateral total hip arthroplasty may affect the progression of osteoarthritis in the contralateral hip.