BACKGROUND:High-level basketball athletes at the collegiate level and in the National Basketball Association (NBA) have a greater proportion of knee cartilage pathology than the nonathlete population. However, little is known as to whether identified pathology on knee magnetic resonance imaging (MRI) correlates with clinical symptoms or orthopaedic history in these players. PURPOSES:(1) To evaluate knee MRI scans in a cross-sectional population of NBA Draft Combine players to establish prevalence of knee pathology, including that of articular cartilage and meniscus in professional basketball players. (2) To identify independent variables including demographic characteristics, playing history, previous knee injury, and symptoms that correlate to these MRI findings. STUDY DESIGN:Cross-sectional study; Level of evidence, 3. METHODS:Players from the NBA Draft Combine over a 2-year period voluntarily participated by undergoing bilateral knee MRI scanning and completing clinical questionnaires. MRI scans were independently and blindly evaluated by 2 radiologists for cartilage assessment (using modified Noyes score) and meniscal pathology. Associations between imaging findings and pain/function scores and orthopaedic history were evaluated. RESULTS:A total of 43 players (80 knees) were included. Intraclass correlation coefficients were a mean of 0.827 for agreement and 0.831 for consistency for the modified Noyes score. Cartilage pathology was identified in 48.3% of knees, with the most common locations being the patella and trochlea. Previous knee surgery was associated with lateral tibial plateau chondral pathology (odds ratio [OR], 6.58; P = .04). Reduced function scores were predictive of cartilage pathology on the lateral femoral condyle (OR, 0.55; P = .03). Increased pain scores were associated with a nonzero modified Noyes score (OR, 6.11; P < .01). CONCLUSION:The incidence of pathology identified on knee MRI scans in players at the NBA Draft Combine without clinical symptoms was high, in line with the hypothesis. Little correlation was found between the objective imaging findings and subjective pain, function, and orthopaedic injury history. Clinicians treating high-level athletes should focus on treating clinically significant findings and be cautious about treating pathology found on imaging that may not explain or correlate with symptoms. It remains critical to study the natural history of imaging findings in these athletes to better ascertain the ultimate effect of sport and physiologic load on disease progression.

OBJECTIVE:This study is to determine whether a needle guidance device combining a 3D-printed component with a smartphone would decrease the number of passes and time required to perform a standard CT-guided needle procedure in a phantom study.MATERIALS AND METHODS:A 3D-printed mechanical guide with built-in apertures for various needle sizes was designed and printed. It was mounted on a smartphone and used to direct commercially available spring-loaded biopsy devices. A smartphone software application was developed to use the phone's sensors to provide the real-time location of a lesion in space, based on parameters derived from preprocedural CT images. The physical linkage of the guide, smartphone, and needle allowed the operator to manipulate the assembly as a single unit, with real-time graphical representation of the lesion shown on the smartphone display. Two radiology trainees and 3 staff radiologists targeted 5 lesions with and without the device (50 total procedures). The number of passes and time taken to reach each lesion were determined.RESULTS:Use of the smartphone needle guide decreased the mean number of passes (with guide, 1.8; without guide, 3.4; P < 0.001) and mean time taken (with guide, 1.6 min; without guide, 2.7 min; P = 0.005) to perform a standard CT-guided procedure. On average, the decreases in number of passes and procedure time were more pronounced among trainees (P < 0.001).CONCLUSION:The combination of a mechanical guide and smartphone can reduce the number of needle passes and the amount of time needed to reach a lesion in a phantom for both trainees and experienced radiologists.

Background:Magnetic resonance imaging (MRI)-based rotator cuff assessment is often qualitative and subjective; few studies have tried to validate such preoperative assessments. This study investigates relationships of preoperative MRI assessments made by conventional approaches to intraoperative findings of tear type, location, and size or MRI-assessed muscle occupation ratio.Methods:Intraoperatively, surgeons assessed tear type, location, anterior-posterior (AP) width, and medial-lateral length in 102 rotator cuff repair patients. Two musculoskeletal radiologists independently assessed the preoperative MRI scans for these same parameters and supraspinatus muscle atrophy by both Warner classification and quantitative occupation ratio. Exact agreement proportions, kappa statistics, and correlation coefficients were used to quantify agreement relationships.Results:Agreement between MRI readers' and surgeons' observations of tear status averaged 93% with κ = 0.38, and that of tear location averaged 77% with κ = 0.50. Concordance correlations of MRI and intraoperative measures of anterior-posterior and medial-lateral tear length averaged 0.59 and 0.56 across readers, respectively. Despite excellent interrater agreement on Warner classification (exact agreement proportion 0.91) and occupation ratio (concordance correlation 0.93) separately, correlations between these 2 measures were -0.54 and -0.64 for the 2 readers, respectively. Patients with Warner grade 0 had occupation ratios ranging from 0.5 to 1.5.Conclusion:Correlations of preoperative MRI tear dimensions and muscle atrophy assessed by conventional approaches with intraoperatively measured tear dimensions and quantitative occupation ratio, respectively, were only fair. Since tear size and muscle atrophy are known strong predictors of outcomes following rotator cuff repair that may influence treatment decisions, surgeons need to be aware of the limitations of MRI methods. Continued development and validation of quantitative preoperative imaging methods to accurately assess these parameters are needed to improve surgical planning and prognosis.

Background: Magnetic resonance imaging (MRI) is standard of care for rotator cuff evaluation, with clinical interpretation usually limited to qualitative judgments. The reliability of MRI-based measurements and scoring systems has been evaluated only preoperatively or >6 months following rotator cuff repair, when repairs are in the later stages of healing. This study describes the MRI assessments and inter-rater agreement of various rotator cuff tendon and muscle parameters evaluated preoperatively and 4 times during the first postoperative year. Methods: Two musculoskeletal radiologists independently assessed MRI scans of 42 patients preoperatively and 3, 12, 26, and 52 weeks after rotator cuff repair. Using standardized reading rules, readers assessed tendon integrity (5-point Sugaya classification), tear dimensions, muscle fat (5-point Goutallier classification) and atrophy (4-point Warner classification), muscle cross-sectional areas, and myotendinous junction distance. Raw exact agreement proportions, K statistics, and correlation coefficients were used to quantify inter-rater agreement. Results: Readers showed moderate to substantial above-chance agreement in scoring rotator cuff tendon integrity and supraspinatus muscle atrophy and good to excellent agreement on tear dimensions and muscle cross-sectional areas but only fair to moderate agreement for fatty infiltration and myotendinous junction distance. Only fatty infiltration grades evidenced observer bias. Inter-rater agreement did not appear time dependent. Conclusion: By use of defined reading rules in a research setting, MRI evaluations of rotator cuff tendon integrity, tear dimensions, muscle atrophy, and cross-sectional areas have reasonable reliability at all time points in the first postoperative year. However, the presence of clinically significant disagreements, even in such favorable circumstances, indicates the need for improved imaging tools for precise rotator cuff evaluation. (C) 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.

Background: Patella alta has been noted to be a risk factor for recurrent patellar instability. Purpose: We conducted a radiographic study to determine whether a patellar tendon imbrication technique normalizes patellar height as well as whether the shortened length is maintained at a minimum 2-year follow-up. Study Design: Case series; Level of evidence, 4. Methods: A total of 54 consecutive patients were identified after a retrospective chart review was performed on patients who underwent patellar tendon imbrication between 2008 and 2013. Preoperative, 3 weeks postoperative, and minimum 2 years postoperative lateral radiographs were analyzed using Insall-Salvati (IS), Blackburne-Peel (BP), and Caton-Deschamps (CD) indices to determine the amount of shortening that was achieved after the procedure and to what degree that shortening was maintained at a minimum 2-year follow-up. Results: A total of 27 patients (32 knees) completed a minimum 2-year follow-up. The mean patellar tendon length preoperatively was 6.1 cm (range, 5-8 cm). At 3 weeks and 2 years, the mean tendon lengths were 5.1 and 5.2 cm, respectively. Thus, the mean ± SD change in patellar tendon length from preoperative to 3 weeks postoperative was 0.97 ± 0.67 cm. IS, BP, and CD ratios had minimal change (loss of correction) from 3-week to 2-year follow-up; the delta values were 0.04, –0.03, and 0.09, respectively. There were no complications directly related to the technique. Conclusion: Patellar tendon imbrication is a safe and effective procedure to correct patella alta in the setting of lateral patellar instability. On average, the technique allowed 1 cm of patellar tendon shortening and maintained the correction at a minimum 2-year follow-up. In the skeletally immature patient, this technique allows correction of patella alta by avoidance of a tibial tuberosity osteotomy.

In this article, the authors aim to focus on the challenges of interpreting shoulder MR imaging in the throwing athlete with an approach formed by evidence-based literature and clinical experience, with a particular focus on superior labrum tears.

To determine whether a 3D magnetic resonance imaging (MRI) sequence with postprocessing applied to simulate computed tomography (CT) (“pseudo-CT”) images can be used instead of CT to measure acetabular version and alpha angles and to plan for surgery in patients with femoroacetabular impingement (FAI). Four readers retrospectively measured acetabular version and alpha angles on MRI and CT images of 40 hips from 20 consecutive patients (9 female patients, 11 male patients; mean age, 26.0 ± 6.5 years) with FAI. 3D models created from MRI and CT images were assessed by 2 orthopedic surgeons to determine the need for femoroplasty and/or acetabuloplasty. Interchangeability of MRI with CT was tested by comparing agreement between 2 readers using CT (intramodality) with agreement between 1 reader using CT and 1 using MRI (intermodality). Intramodality and intermodality agreement values were nearly identical for acetabular version and alpha angle measurements and for surgical planning. Increases in inter-reader disagreement for acetabular version angle, alpha angle, and surgical planning when MRI was substituted for CT were − 2.1% (95% confidence interval [CI], − 7.7 to + 3.5%; p = 0.459), − 0.6% (95% CI, − 8.6 to + 7.3%; p = 0.878), and 0% (95% CI, − 15.1 to + 15.1%; p = 1.0), respectively, when an agreement criterion ≤ 5° was used for angle measurements. Pseudo-CT MRI was interchangeable with CT for measuring acetabular version and highly favorable for interchangeability for measuring alpha angle and for surgical planning, suggesting that MRI could replace CT in assessing patients with FAI.

BACKGROUND:MRI acceleration using deep learning (DL) convolutional neural networks (CNNs) is a novel technique with great promise. Increasing the number of convolutional layers may allow for more accurate image reconstruction. Studies on evaluating the diagnostic interchangeability of DL reconstructed knee magnetic resonance (MR) images are scarce. The purpose of this study was to develop a deep CNN (DCNN) with an optimal number of layers for accelerating knee magnetic resonance imaging (MRI) acquisition by 6-fold and to test the diagnostic interchangeability and image quality of nonaccelerated images versus images reconstructed with a 15-layer DCNN or 3-layer CNN. METHODS:For the feasibility portion of this study, 10 patients were randomly selected from the Osteoarthritis Initiative (OAI) cohort. For the interchangeability portion of the study, 40 patients were randomly selected from the OAI cohort. Three readers assessed meniscal and anterior cruciate ligament (ACL) tears and cartilage defects using DCNN, CNN, and nonaccelerated images. Image quality was subjectively graded as nondiagnostic, poor, acceptable, or excellent. Interchangeability was tested by comparing the frequency of agreement when readers used both accelerated and nonaccelerated images to frequency of agreement when readers only used nonaccelerated images. A noninferiority margin of 0.10 was used to ensure type I error ≤5% and power ≥80%. A logistic regression model using generalized estimating equations was used to compare proportions; 95% confidence intervals (CIs) were constructed. RESULTS:DCNN and CNN images were interchangeable with nonaccelerated images for all structures, with excess disagreement values ranging from -2.5% [95% CI: (-6.1, 1.1)] to 3.0% [95% CI: (-0.1, 6.1)]. The quality of DCNN images was graded higher than that of CNN images but less than that of nonaccelerated images [excellent/acceptable quality: DCNN, 95% of cases (114/120); CNN, 60% (72/120); nonaccelerated, 97.5% (117/120)]. CONCLUSIONS:Six-fold accelerated knee images reconstructed with a DL technique are diagnostically interchangeable with nonaccelerated images and have acceptable image quality when using a 15-layer CNN.

OBJECTIVE. Cartilage loss on preoperative knee MRI is a predictor of poor outcomes after arthroscopic partial meniscectomy. The purpose of this study was to compare the ability to predict outcomes after arthroscopic partial meniscectomy with a clinically used modified Outerbridge system versus a semiquantitative MRI Osteoarthritis Knee Score system for grading cartilage loss. MATERIALS AND METHODS. Patients who underwent preoperative knee MRI within 6 months of arthroscopic partial meniscectomy and who had outcomes available from the time of surgery and 1 year later were eligible for inclusion. Cases were evaluated by two radiologists and one radiology fellow with the use of both grading systems. The accuracy of each system in discriminating between surgical success and failure was estimated using the ROC curve (AUC) with 95% CIs. A Wald test was used to assess noninferiority of the clinical grading system. Interreader agreement regarding the accuracy of the grading systems in predicting outcomes was also compared. RESULTS. A total of 78 patients (38 women and 40 men; mean age, 56.6 years) were included in the study. A prediction model using clinical grading (AUC = 0.695; 95% CI, 0.566-0.824) was noninferior (p = 0.047) to a model using MRI Osteoarthritis Knee Score grading (AUC = 0.683; 95% CI, 0.539-0.827). Both MRI prediction models performed better than a model using demographic characteristics only (AUC = 0.667; 95% CI, 0.522-0.812). Inter-reader agreement with clinical grading (80.8%) was higher than that with MRI Osteoarthritis Knee Score grading (65.0%; p = 0.012). CONCLUSION. A clinically used system to grade cartilage loss on MRI is as effective as a semiquantitative system for predicting outcomes after arthroscopic partial meniscectomy, while also offering improved interreader agreement.

To characterize the appearance, location, severity, and prevalence of focal glenoid retroversion on shoulder MRI in professional baseball pitchers versus age-matched controls.

BACKGROUND:The anterolateral ligament (ALL) has been described as an extracapsular stabilizer of knee rotational stability. Investigators have shown a renewed interest in the ALL and further evaluated its anatomy and biomechanical role as a knee stabilizer. The appearance of the ALL on magnetic resonance imaging (MRI) remains inconsistent across the literature. PURPOSE:The aims of this study were 2-fold. The first objective was to further investigate the appearance of the uninjured ALL on MRI and provide data regarding interrater agreement in identifying the ligament. The second objective was to describe the incidence of concomitant ALL injuries in anterior cruciate ligament (ACL)-injured knees and provide data regarding interrater agreement in identifying and grading these injuries. STUDY DESIGN:Cohort study (diagnosis); Level of evidence, 3. METHODS:Fifty consecutive MRI scans of non-ACL-injured knees (control) and 50 consecutive MRI scans of ACL-injured knees performed at a single sports medicine center were identified. Three musculoskeletal radiologists independently reviewed the MRI scans in a randomized and blinded fashion. In the control group, the reviewers classified the ALL as visualized or not and did so for the proximal, middle, and distal thirds of the ligament. In the ACL tear group, the reviewers classified the ALL as visualized or not for each third of the ligament. They noted whether the ligament was injured and graded the injury as low, intermediate, or high. RESULTS:All 3 segments of the ALL were visualized in a mean 11% of patients. The ALL was partially visualized in a mean 68% of patients. The distal third of the ALL was injured 28% (14/50) of the time in the ACL tear group. The agreement rate among raters for classifying the injury status was fair to poor. CONCLUSION:Visualization of the ALL was inconsistent in the current study. Identifying and grading an injury to the ALL were difficult and had poor interobserver agreement. Using MRI to aid in the diagnosis of an ALL injury in the setting of an ACL tear is unreliable according to our study results. Further research looking at consistent ALL identification and injury patterns should be undertaken.

Background: We sought to determine whether there are ultrasound parameters that differ between knees with symptomatic fat pad synovial impingement and asymptomatic knees.& para;& para;Methods: A prospective study was performed in patients with clinical signs and symptoms of fat pad synovial impingement and asymptomatic controls. Eleven symptomatic knees and 10 asymptomatic controls were evaluated. Ultrasound imaging was performed before and after exercise. Evaluated parameters included largest fat lobule compressibility, subjective assessment of vascularity, largest vessel diameter, and subjective assessment of dynamic fat pad motion during flexion and extension. Receiver operating characteristic (ROC) curve analysis was used to assess whether changes in these parameters were different between symptomatic and asymptomatic knees. & para;& para;Results: Change in the largest vessel diameter was greater and trended toward dilation in asymptomatic knees compared to symptomatic knees (mean: 0.83 vs. - 0.02; P < 0.001). No significant differences were observed between symptomatic and asymptomatic knees with respect to pre-exercise versus post-exercise states in subjective assessment of vascularity (P = 0.131), fat pad motion (P = 0.115), or percent change of the largest fat lobule (P = 0.241). However, overall compressibility of the fat pad lobule was significantly diminished in the pre-exercise state in symptomatic knees compared to asymptomatic controls.& para;& para;Conclusions: This study demonstrated a statistically significant change in the largest vessel diameter from pre- to post-exercise states between symptomatic and asymptomatic knees, as well as abnormal pre-exercise fat lobule compressibility in symptomatic knees. These findings show promise that with further research, ultrasound could have clinical utility in diagnosing infrapatellar fat pad impingement. (C) 2018 Elsevier B.V. All rights reserved.

To provide an overview of common sports-related shoulder pathology and review recently published studies from 2015 to 2016, with an emphasis on imaging.

Biostatistics is an essential component in most original research studies in imaging. In this article we discuss five key statistical concepts for study design and analyses in modern imaging research: statistical hypothesis testing, particularly focusing on noninferiority studies; imaging outcomes especially when there is no reference standard; dealing with the multiplicity problem without spending all your study power; relevance of confidence intervals in reporting and interpreting study results; and finally tools for assessing quantitative imaging biomarkers. These concepts are presented first as examples of conversations between investigator and biostatistician, and then more detailed discussions of the statistical concepts follow. Three skeletal radiology examples are used to illustrate the concepts.

To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI.

OBJECTIVE The objective of this study was to compare reader accuracy detecting lesions near hardware in a CT phantom model at different radiation exposures using an advanced metal artifact reduction (MAR) algorithm and standard filtered back projection (FBP) techniques and to determine if radiation exposure could be decreased using MAR without compromising lesion detectability. MATERIALS AND METHODS A CT phantom manufactured with spherical lesions of various sizes (10-20 mm) and attenuations (20-50 HU) embedded around cobalt-chromium spheres attached to titanium rods, simulating an arthroplasty, was scanned on a single CT scanner (FLASH, Siemens Healthcare) at 140 kVp and 0.6-mm collimation using clinical-dose (300 Quality Reference mAs [Siemens Healthcare]), low-dose (150 Quality Reference mAs), and high-dose (600 Quality Reference mAs) protocols. Images reconstructed with iterative MAR, advanced modeled iterative reconstruction (ADMIRE), and FBP with identical parameters were anonymized and independently reviewed by three radiologists. Accuracies for detecting lesions, measured as AUC, sensitivity, and specificity, were compared. RESULTS Accuracy using MAR was significantly higher than that using FBP at all exposures (p values ranged from < 0.001 to 0.021). Sensitivity was also higher for MAR than for FBP at all exposures. Specificity was very high for both reconstruction techniques at all exposures with no significant differences. Accuracy of low-dose MAR was higher than and not inferior to standard-dose and high-dose FBP. MAR was significantly more sensitive than FBP in detecting smaller lesions (p = 0.021) and lesions near high streak artifact (p < 0.001). CONCLUSION MAR improves reader accuracy to detect lesions near hardware and allows significant reductions in radiation exposure without compromising accuracy compared with FBP in a CT phantom model.

OBJECTIVEThe purpose of this study was to compare the diagnostic performance of a 5-minute shoulder MRI protocol consisting of multiplanar 2D fast spin-echo (FSE) sequences with parallel imaging to that of a standard shoulder MRI protocol.MATERIALS AND METHODSA retrospective review of 151 3-T MRI examinations of shoulders of 147 patients (mean age, 46.95 years) and 50 1.5-T MRI examinations of shoulders of 50 patients (mean age, 53.74 years) with four fast and five standard sequences from two academic centers between January 2014 and April 2015 was performed by three musculoskeletal radiologists. Interchangeability of fast and standard MRI was tested by comparing interprotocol (fast vs standard) interreader agreement with standard MRI interreader agreement. Interreader agreement was also compared using kappa statistics. The frequency of major findings was compared using an adjusted McNemar test. Sensitivity and specificity of MRI were measured for 51 patients who underwent surgery.RESULTSInterprotocol reader agreement was essentially equal to reader agreement on standard MRI (mean difference ≤ 1%; 95% CI, -3.8% to 3.9%; 61-96% across structures). Interprotocol kappa values (0.373-0.645) were similar to standard MRI kappa values (0.320-0.726). Frequencies of major findings on fast and standard MRI were similar (0.7-19.6% across structures; p ≥ 0.08). Sensitivities of fast MRI for tendon and labral tears (33-92%) were equivalent or higher than those of standard MRI with similar specificities (77-98%).CONCLUSIONFast 5-minute shoulder MRI with multiplanar 2D FSE sequences using parallel imaging is interchangeable, with similar interreader agreement and accuracy, with standard shoulder MRI for evaluating shoulder injuries.

Objectives: Injuries to the shoulder are a common cause of missed playing time in professional baseball athletes. These injuries predominately involve the supraspinatus tendon or the glenoid labrum. The purpose of this project is to describe a series of throwing-related injuries to the subscapularis muscle-tendon complex that have been previously unreported amongst baseball players. Additionally, it is the goal to describe a mechanism of injury as well as a treatment program for these athletes. Methods: A retrospective review of shoulder magnetic resonance imaging (MRI) scans of players from 1 Major League Baseball organization over the course of 5 years was performed to identify cases with findings suggestive of a subscapularis injury. The MRIs were graded and the medical records were reviewed to assess clinical findings, treatment plans, and follow-up. In the injured cohort, preinjury baseline measurements of shoulder motion including external rotation at 90° of abduction were compared to measurements from a non-injured baseball athlete cohort to evaluate whether decrease external rotation is a risk factor for this injury. Results: A total of 133 MRI scans of the shoulder were evaluated. Eleven of the 133 MRIs demonstrated signal changes suggesting subscapularis injury. Ten of these 11 patients had clinical findings supporting a diagnosis of throwing-related subscapularis strain. There were 4 grade I, 4 grade II, and 2 grade III injuries. All injuries occurred in the inferior half of the subscapularis at the myotendinous junction. Risk of subscapularis injury increased with lower levels of dominant arm external rotation (odds ratio, 0.89; 95% CI, 0.82-0.94; P < .001). A threshold of dominant arm external rotation of less than 106° demonstrated sensitivity of 0.700 (95% CI, 0.392-0.897) and specificity of 0.951 (95% CI, 0.888-0.982) for subscapularis injury. All players were treated conservatively without surgery; only 1 did not return to play. Of the remaining players, the mean number of days missed because of injury was 27 (range, 11-61 days). Conclusion: Throwing-related subscapularis injuries occur in the inferior half of the muscle at the myotendinous junction. The subscapularis muscle fibers are oriented along a fan shape because of the relatively narrow insertion on the lesser tuberosity of the proximal humerus and a broader origin on the scapula with muscle fiber alignment dependent on arm position. When the thrower's arm is at 90 degrees of abduction and external rotation, the inferior fibers of the subscapularis comes to be aligned in the transverse plane across the glenohumeral joint and are placed on greatest stretch during the late cocking and early acceleration phases of throwing. Our data suggest that there is an increased risk of these injuries with lower levels of dominant arm external rotation as this shorter arc requires greater force production by the subscapularis muscle to achieve the same peak throwing velocity.

Repetitive, high-velocity overhead throwing can lead to several adaptive changes in the throwing shoulder, which over time lead to structural microtrauma and eventually overt injury. MR imaging is a useful imaging modality to evaluate these changes and to characterize their acuity and severity. Understanding the throwing motion and the effects of this motion on the structures of the shoulder can help radiologists to recognize these findings and provide useful information to referring physicians, which may affect the treatment of these athletes. This article reviews shoulder pathomechanics and MR imaging findings in overhead throwing athletes.