Efficacy of Ultrasound-Guided Glenohumeral Joint Injections of Leukocyte-Poor Platelet-Rich Plasma Versus Hyaluronic Acid in the Treatment of Glenohumeral Osteoarthritis: A Randomized, Double-Blind Controlled Trial.

OBJECTIVE: To compare the efficacy of ultrasound-guided hyaluronic acid (HA) versus leukocyte-poor platelet-rich plasma (LP-PRP) injection in the treatment of glenohumeral osteoarthritis. DESIGN: Double-blind randomized controlled trial. SETTING: Academic institution. PATIENTS: Seventy patients with chronic glenohumeral osteoarthritis were randomly assigned to receive a single injection of HA (n = 36) or LP-PRP (n = 34). INTERVENTIONS: Leukocyte-poor platelet-rich plasma was processed using Harvest/TerumoBCT Clear PRP kits. Ultrasound-guided injections of 6 mL HA or 6 mL LP-PRP into the glenohumeral joint were performed. Patients, the injecting physician, and outcomes assessor were blinded to treatment assignments. MAIN OUTCOME MEASURES: Shoulder Pain and Disability Index (SPADI), American Shoulder and Elbow Surgeons (ASES) score, current/average numerical rating scale (NRS) pain scores, satisfaction, and side effects were assessed at the 5 follow-up time points over 12 months. RESULTS: Baseline characteristics were similar between groups. There were no significant between-group differences regarding SPADI, ASES, and current/average NRS pain scores at any time point up to 12 months postinjection ( P > 0.05). However, significant improvements in SPADI, ASES, and current/average NRS pain scores were observed in both groups starting at 1 or 2 months ( P < 0.01, P < 0.01, P < 0.001, and P < 0.01, respectively). These improvements were observed regardless of osteoarthritis severity. For patients who received LP-PRP, there was no effect of platelet yield on outcomes. Side effect and satisfaction rates were similar between groups. CONCLUSIONS: There were no differences in pain and functional outcomes after a single injection of LP-PRP versus HA. However, significant improvements in pain and function were observed after both treatments in patients with glenohumeral osteoarthritis.

Ultrasound of the distal biceps brachii tendon using four approaches: reproducibility and reader preference.

OBJECTIVES: To determine which sonographic appearance of the distal biceps brachii tendon (DBBT) is preferred by readers, and if images obtained by two different operators are reproducible. METHODS: We performed an IRB-approved prospective sonographic evaluation of the DBBT in 50 healthy elbows using four different approaches (anterior, lateral, medial, posterior) performed by two operators. Five musculoskeletal radiologists independently reviewed the images, and ranked the four approaches based on overall appearance of echogenicity of the tendon, visualized length, and visualization of the insertion. RESULTS: The medial approach was preferred in 79.6% of elbows, anterior in 17.6%, lateral in 2.8%, and the posterior approach was never preferred. The difference was statistically significant (P < 0.001). Kappa values for the five readers were 0.61 to 0.8 for choosing the images produced by the medial approach. CONCLUSION: The appearance of the DBBT using the medial approach is preferred by readers and is reproducible between different operators.

What is the Diagnostic Accuracy of MRI for Component Loosening in THA?

BACKGROUND: Implant loosening is a common cause of reoperation after THA. Plain radiographs have been the default modality to evaluate loosening, although radiographs provide a relatively insensitive assessment of integration; cross-sectional modalities may provide a more detailed evaluation but traditionally have suffered from metal-related artifacts. We sought to determine whether MRI is capable of reliably detecting operatively confirmed component loosening in patients after hip arthroplasty. QUESTIONS/PURPOSES: (1) Is assessing implant integration using MRI (with multiacquisition variable resonance image combination, [MAVRIC]) repeatable between readers? (2) What is the sensitivity and specificity of MRI with MAVRIC to evaluate component loosening, using intraoperative assessment as a gold standard? (3) How does the sensitivity and specificity of MRI with MAVRIC for surgically confirmed component loosening compare with those of radiographs? METHODS: Between 2012 and 2017, 2582 THAs underwent revision at one institution. Of those, 219 had a preoperative MRI with MAVRIC. During that period, the most common indication for obtaining an MRI was evaluation of potential adverse local tissue reaction. The surgeons' decision to proceed with revision was based on their overall assessment of clinical, imaging, and laboratory findings, with MRI findings cited as contributing to the decision to revise commonly occurring in the setting of recalled implants. Of the THAs that underwent MRI, 212 were included in this study, while seven were excluded due to equivocal operative notes (5) and excessively poor quality MRI (2). MRI was performed at 1.5T using a standardized arthroplasty imaging protocol, including MARS (metal artifact reduction sequencing) and MAVRIC techniques. Two independent musculoskeletal fellowship-trained readers (one with 26 and one with 5 years of experience) blinded to operative findings scored a subset of 57 hips for implant integration based on Gruen zone and component loosening (defined as complete circumferential loss of integration around a component) to evaluate interobserver reliability. A third investigator blinded to imaging findings reviewed operative notes for details on the surgeon's assessment of intraoperative loosening. RESULTS: Gwet's agreement coefficients (AC) were used to describe interobserver agreement; these are similar to Cohen's kappa but are more resistant to certain paradoxes, such as unexpectedly low values in the setting of very high or low trait prevalence, or good agreement between readers on marginal counts. Almost perfect interobserver agreement (AC2 = 0.81-1.0) was demonstrated for all acetabular zones and all femoral Gruen zones on MRI, while perfect (AC1 = 1.0) agreement was demonstrated for the overall assessment of acetabular component loosening and near perfect agreement was shown for the assessment of femoral component loosening (AC1 = 0.98). MRI demonstrated a sensitivity and specificity of 83% (95% CI, 65-96) and 98% (95% CI, 97-100), respectively, for acetabular component loosening and 75% (95% CI, 55-94) and 100% (95% CI, 100-100), respectively, for femoral component loosening. Radiographs demonstrated a sensitivity and specificity of 26% (95% CI, 12-47) and 100% (95% CI, 96-100), respectively, for acetabular component loosening and 20% (95% CI, 9-47) and 100% (95% CI, 100-100), respectively, for femoral component loosening. CONCLUSION: MRI may provide a repeatable assessment of implant integration and demonstrated greater sensitivity than radiographs for surgically confirmed implant loosening in patients undergoing revision THA at a single institution. Additional multi-institutional studies may provide more insight into the generalizability of these findings. LEVEL OF EVIDENCE: Level III, diagnostic study.

A new, MRI-based classification system for tibial spine fractures changes clinical treatment recommendations when compared to Myers and Mckeever.

PURPOSE: Tibial spine fractures (TSFs) are graded according to the Meyers and McKever (MM) classification system, which is based on a qualitative evaluation of plain radiographs. However, although MRI images can provide important information about these fractures, there is no MRI-based classification system. This study aims to (1) establish the intra- and inter-rater reliability of the MM system for use with radiographs, (2) propose a quantitative, MRI-based system and compare its reliability to the MM system, and (3) assess how often using the MRI-based system changes the classification and potential treatment plan as previously determined using MM. METHODS: The MRI-based system was designed with three grades based on quantitative displacement patterns of the fractured fragment and tissue entrapment. Four raters from a tertiary care center evaluated 20 fractures according to the MM and MRI-based systems. Observers graded images at two time points at least 2 weeks apart, after which we compared the intra- and inter-rater reliability of each system (using Fleiss' kappa and weighted kappa, respectively) and assessed how often using the MRI-based system changed the fracture grade. RESULTS: Both the MM and MRI-based systems exhibit fair to moderate intra- and inter-rater reliability (average kappa values ranged from 0.38 to 0.66). Use of the MRI-based system changed the fracture grade and as a result modified the treatment recommendations in 32.5% of cases: 6.9% were previously unnoticed fractures, 13.1% underwent a raise in grade, and 12.5% were graded as lower than before. CONCLUSION: The MRI-based system is as reliable as the MM system and provides specific, quantitative criteria for classifying fractures according to fragment displacement and tissue entrapment. The new MRI-based system potentially clarifies treatment indications for TSFs. LEVEL OF EVIDENCE: Diagnostic Study, Level II.

Technical Developments: Zero Echo Time Imaging of the Shoulder: Enhanced Osseous Detail by Using MR Imaging.

Purpose To determine the intermodality agreement of morphologic grading and clinically relevant quantitative measurements between computed tomography (CT) and zero echo time (ZTE) magnetic resonance (MR) imaging of the shoulder. The primary objective was to demonstrate the clinical applicability of ZTE in osseous shoulder imaging. Materials and Methods Thirty-four patients undergoing standard-of-care (SOC) MR imaging with concomitant CT were enrolled in this institutional review board-approved study. ZTE images were acquired after SOC MR imaging. Glenoid morphology (version, vault depth, erosion), injury or disease (osteoarthritis, Bankart and Hill-Sachs lesions, subchondral cysts), and evidence of prior surgery were graded or measured. κ Values, intraclass correlation coefficients (ICCs), and Bland-Altman limits of agreement were used to establish agreement. Qualitative comparison of osseous findings was performed between ZTE and SOC MR imaging. Results Binary classification and nominal/ordinal grades showed substantial or better agreement between raters and modalities (κ or ICC > 0.6). Continuous measurements exhibited strong correlation between raters and modalities, although not universally. Bankart ICCs were not significant, owing to low prevalence. ZTE exhibited greater conspicuity of enthesopathic cysts and marrow edema. In 21 of 34 cases, ZTE imaging of osseous features exceeded SOC MR imaging. Conclusion ZTE MR imaging provides "CT-like" contrast for bone. The results of this study demonstrate strong intermodality agreement between measurements and grades from CT and ZTE images in a cohort of patients undergoing imaging with both modalities. A majority of ZTE image sets provided superior visualization of osseous features when compared with SOC MR image sets. This superiority coupled with strong quantitative agreement with CT suggests that ZTE may be used clinically in lieu of CT in some cases. © RSNA, 2017 Online supplemental material is available for this article.

MRI Arthroscopy Correlations: Ligaments of the Knee.

Magnetic resonance imaging and a thorough understanding of its interpretation in the diagnosis and management of injuries to the ligaments about the knee is an essential skill for orthopedists. The goal of this review is to provide a description of the native and injured anatomy through magnetic resonance imaging and its correlations, when appropriate, as seen through the arthroscope at the time of surgery. The ligaments of focus include the anterior cruciate ligament, the posterior cruciate ligament, the medial collateral ligament, the posterolateral corner, the anterolateral ligament, and the medial patellofemoral ligament.

Optimal Starting Point for Fifth Metatarsal Zone II Fractures: A Cadaveric Study.

BACKGROUND: Identifying the optimal starting point for intramedullary fixation of tibia and femur fractures is well described in the literature using a retrograde or anterograde technique. This technique has not been applied to the fifth metatarsal, where screw trajectory can cause iatrogenic malreduction. The generally accepted starting point for the fifth metatarsal is "high and inside" to accommodate the fifth metatarsal's dorsal apex and medial curvature. We used a retrograde technique to identify the optimal starting position for intramedullary fixation of fifth metatarsal fractures. METHODS: Five matched cadaveric lower extremity pairs were dissected to the fifth metatarsal neck. An osteotomy was made to access the intramedullary canal. A retrograde reamer was passed to the base of the fifth metatarsal to ascertain the ideal entry point. Distances from each major structure on the lateral aspect of the foot were measured. Computed tomography scans helped assess base edge measurements. RESULTS: In 6 of 10 specimens, the retrograde reamer hit the cuboid with a cuboid invasion averaging 0.7 mm. The peroneus brevis and longus were closest to the starting position with an average distance of 5.1 mm and 5.7 mm, respectively. Distances from the entry point to the dorsal, plantar, medial, and lateral edges of the metatarsal base were 8.3 mm, 6.9 mm, 9.7 mm, and 9.7 mm, respectively. CONCLUSION: Optimal starting position was found to be essentially at the center of the base of the fifth metatarsal at the lateral margin of the cartilage. Osteoplasty of the cuboid or forefoot adduction may be required to gain access to this site. CLINICAL RELEVANCE: This study evaluated the ideal starting position for screw placement of zone II base of the fifth metatarsal fractures, which should be considered when performing internal fixation for these fractures.

Rupture of the short head component of a bifurcated distal biceps tendon.

BACKGROUND: Rupture of the short head component of a bifurcated distal biceps tendon is a rare injury that may be difficult to diagnose and to treat. METHODS: Three cases of patients with selective disruption of the short head of the biceps distal tendon from a single institution are reported. The presenting history, physical examination, imaging studies, operative findings, and treatment strategies are described. RESULTS: In each case, the mechanism of injury was forceful flexion of the involved elbow against an eccentric load. Notable physical examination findings included a palpable tendon in the antecubital fossa, a "reverse Popeye" deformity, and pain and weakness with resisted forearm supination and elbow flexion. Careful review of the magnetic resonance imaging studies demonstrated the classic findings for this unique injury. All 3 patients successfully returned to their baseline level of activity after anatomic repair of the short head component with or without independent repair of the long head component (depending on the degree of partial tearing seen intraoperatively). DISCUSSION/CONCLUSIONS: Rupture of the short head component of a bifurcated distal biceps tendon is a rare injury that can be easily misdiagnosed and mistreated. A meticulous physical examination and evaluation of imaging is required to differentiate this injury from a partial or complete tear of a common distal biceps tendon. Clinicians should maintain a high index of suspicion for this unusual injury pattern. When it is diagnosed appropriately, selective disruption of the short head of the biceps distal tendon may be effectively treated with anatomic repair.

The Clinical Severity of Patients Diagnosed With an In-Hospital Pulmonary Embolism Following Modern, Elective Joint Arthroplasty Is Unrelated to the Location of Emboli in the Pulmonary Vasculature.

BACKGROUND: In the event of a postoperative pulmonary embolism (PE), it is generally believed that patients with centrally located emboli will have worse clinical symptoms than those with segmental or subsegmental ones. We studied if a relationship exists between the clinical severity at the time of PE diagnosis and the location of the emboli within the pulmonary vasculature. METHODS: All 269 patients who developed an in-hospital, computed tomography pulmonary angiography-proved, PE following elective total hip arthroplasty or total knee arthroplasty in our institution were studied. The clinical severity of the PE was calculated using the Pulmonary Embolism Severity Index (PESI) that classifies patients in 5 classes (class 5: most severe). All computed tomography pulmonary angiographies were re-reviewed to determine the location of the emboli within the pulmonary vasculature (central, segmental, or subsegmental-unilateral or bilateral). The association between PESI and the PE location was examined. RESULTS: The most proximal location of the emboli was central in 62, segmental in 139, and subsegmental in 68. There were 180 unilateral and 89 bilateral PE patients. There was no association between the PESI and the location of the emboli within the pulmonary vasculature (P = .32). Patients with bilateral or unilateral lung involvement had similar PESI (P = .78). CONCLUSION: The PESI, a recognized, validated predictor of mortality after PE was similar in patients with central, segmental, or subsegmental PE; and in patients with unilateral or bilateral lung involvement. The present study may aid clinicians while assessing and discussing the severity of PE symptoms with patients at the time of diagnosis.

One-Year All-Cause Mortality of Patients Diagnosed as Having In-Hospital Pulmonary Embolism After Modern Elective Joint Arthroplasty Is Low And Unaffected By Radiologic Severity.

BACKGROUND: We studied the 1-year complication rate of patients diagnosed as having a pulmonary embolism (PE) after elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) surgery and the distribution of emboli in the pulmonary circulation, and determined if a relationship exists between the location of the PE and age, gender, body mass index, preoperative predisposing factors, American Society of Anesthesiology classification, type of surgery, prophylaxis, hospital stay, transfer to a higher level of care, and mortality. METHODS: Two hundred sixty-nine patients who developed an in-hospital PE proved by computed tomography pulmonary angiography after elective THA or TKA between 2005 and 2012 were studied. RESULTS: The most proximal location of the emboli was central in 62, segmental in 139, and subsegmental in 68. Nineteen patients (7%) developed a bleeding complication during PE treatment. Twenty-nine patients (11%) were readmitted during the first year. Two patients (0.74%) died: one had a segmental PE after TKA. He died 11 months after surgery due to an autopsy-proven sepsis. The second patient developed a segmental PE after THA. She was anticoagulated, developed an intracranial bleed, and died 8 months after surgery. Multivariate analysis showed that demographic variables, American Society of Anesthesiology class, preoperative comorbidities (with the exception of arrhythmia), and the presence of preoperative predisposing factors had no effect in the location of the PE. CONCLUSION: The 1-year mortality rate of these patients is low. Death can be caused by bleeding complications secondary to anticoagulation or by unrelated conditions. This information may aid clinicians while counseling patients who developed a PE after surgery, particularly those with small subsegmental emboli.

Multiplanar CT Analysis of Fifth Metatarsal Morphology: Implications for Operative Management of Zone II Fractures.

BACKGROUND: Percutaneous internal fixation is currently the method of choice treating proximal zone II fifth metatarsal fractures. Complications have been reported due to poor screw placement and inadequate screw sizing. The purpose of this study was to define the morphology of the fifth metatarsal to help guide surgeons in selecting the appropriate screw size preoperatively. METHODS: Multiplanar analysis of fifth metatarsal morphology was completed using computed tomographic (CT) scans from 241 patients. Specific parameters were analyzed and defined in anteroposterior (AP), lateral, and oblique views including metatarsal length, distance from the base to apex of curvature, apex medullary canal width, apex height, and fifth metatarsal angle. RESULTS: The average metatarsal length in the AP view was 71.4 ± 6.1 mm and in the lateral view 70.4 ± 6.0 mm, with 95% of patients having lengths between 59.3 and 83.5 mm and 58.4 and 82.4 mm, respectively. The average canal width at the apex of curvature was 4.1 ± 0.9 mm in the AP view and 5.3 ± 1.1 mm in the lateral view, with 95% of patients having widths between 2.2 and 5.9 mm and 3.2 and 7.5 mm, respectively. Average distance from apex to base was 42.6 ± 5.8 mm in the AP and 40.4 ± 6.4 mm in the lateral views. Every measurement taken in all 3 views had a significant correlation with height. CONCLUSIONS: When determining screw length, we believe lateral radiographs should be used since the distance from the base of the metatarsal to the apex was smaller in the lateral view. On average, the screw should be 40 mm or less to reduce risk of distraction. For screw diameter, the AP view should be used because canal shape is elliptical, and width was found to be significantly smaller in the AP view. Most canals can accommodate a 4.0- or 4.5-mm-diameter screw, and one should use the largest diameter screw possible. Larger individuals were likely to have more bowing in their metatarsal shaft, which may lead to a higher tendency to distract. LEVEL OF EVIDENCE: Level III, comparative series.

Posterior Humeral Avulsion of the Glenohumeral Ligament and Associated Injuries: Assessment Using Magnetic Resonance Imaging.

BACKGROUND: Lesions associated with posterior humeral avulsion of the glenohumeral ligament (HAGL) can lead to persistent symptoms related to posterior shoulder instability and can be commonly missed or delayed in diagnosis. PURPOSE: To identify and characterize the MRI findings in patients with a posterior HAGL lesion. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: This retrospective case series included 27 patients (28 shoulders) identified by search through the senior authors' databases, with cross-reference to their institutional radiologic communication system for MRI review. Baseline patient demographic data were collected, including age and sex. All posterior HAGL lesions were identified on MRI and characterized as partial, complete, or floating lesions. All acute glenohumeral pathologic changes concurrent with the posterior HAGL were documented. Chondrolabral retroversion of the injured shoulder was measured on axial MRI. RESULTS: The average age of the identified cohort was 33.6 years (range, 15-81 years), and 23 patients were male (86%). Posterior HAGL injuries were found to be complete tears (71%), partial tears (25%), and floating lesions (4%); concomitant bony HAGL avulsion was found in 7% of injuries. Additional traumatic glenohumeral disorders occurred in 93% of cases. The most common concurrent injuries were reverse Hill-Sachs lesions (36%), anterior Bankart lesions (29%), and posterosuperior rotator cuff tears (25%). Notably, concomitant anterior labral or capsular injury was found in 50% of patients, signifying bidirectional disruption of the capsule. In addition, increased chondrolabral version was found in this cohort (10.2° ± 3.7° retroversion). CONCLUSION: This study depicts the high association of combined injury with posterior HAGL lesions and increased chondrolabral retroversion. Findings on MRI related to a posterior HAGL injury could potentially be masked by additional injury and may occur with mechanisms that also lead to anterior glenohumeral disorders.

Rate of Union After Segmental Midshaft Shortening Osteotomy of the Lesser Metatarsals.

BACKGROUND: Current literature reports excellent rates of union following various lesser metatarsal osteotomy techniques. However, it is our experience that segmental midshaft shortening osteotomies heal very slowly and have a greater potential for nonunion than has previously been reported. The purpose of this study was to assess union rates and report the time required for segmental midshaft shortening osteotomies to achieve radiographic union. METHODS: We reviewed the charts and postoperative radiographs of 58 patients (representing 91 osteotomies) who underwent segmental midshaft shortening osteotomies with internal fixation between January 2009 and December 2013. Radiographs were reviewed to determine when union was achieved. Union was defined as the bridging of 2 or more cortices in the anteroposterior, lateral, and oblique radiographic views. Osteotomies were classified as delayed union if they were not healed at 3 months postoperatively and nonunions if they were not healed at 6 months postoperatively. RESULTS: Overall, 27 of 91 osteotomies met our radiographic classification of union and were healed by 3 months (29.7%). Sixty-nine of the 91 osteotomies healed by 6 months (75.8%) and were considered delayed unions. Twenty-two osteotomies were not healed yet and therefore were considered nonunions (24.2%). Of the 22 nonunions, 7 healed in an additional 2 months (8 months) for an overall healing percentage of 83.5%, (76 of 91). By 10 months, 6 more nonunions were healed (overall healing percentage of 90.1%, 82 of 91). Three additional nonunions went on to heal by 12.9 months, yielding a final union rate of 93.4% (85 of 91), while 6 were still considered nonunions (6.6%). CONCLUSION: We report that a significant percentage of segmental midshaft metatarsal shortening osteotomies experienced delayed unions and nonunions. These findings contrast those previously reported in the literature that metatarsal osteotomies have very low nonunion rates. These results support our hypothesis that these osteotomies require a prolonged amount of time to achieve bony healing and that they have a higher tendency to develop delayed and nonunions than previously reported. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Imaging of shoulder arthroplasty.

Imaging is central to the pre- and postoperative evaluation of shoulder arthroplasty, which is increasingly performed due to its clinical efficacy. Implant design, indications, and common complications affecting the different types of shoulder prostheses are reviewed.

Magnetic resonance imaging of shoulder arthroplasty: review article.

BACKGROUND: Magnetic resonance (MR) imaging evaluation of the painful failed shoulder arthroplasty is a useful imaging modality due to advancements in metal artifact reduction techniques, which allow assessment of the integrity of the supporting soft-tissue envelope and the implant. QUESTIONS/PURPOSES: The focus of this pictorial review is to illustrate the benefits of MR imaging, whether used alone or as an adjunct to other imaging modalities, in aiding the clinician in the complex decision making process. METHODS: A PubMed (MEDLINE) search focusing on the complications and imaging assessment of shoulder arthroplasty was performed. Articles were selected for review based on their pertinence to the aforementioned topics. RESULTS: We discuss the ability of MR imaging to identify why a patient's arthroplasty may have failed. Specific causes including component loosening and implant failure, rotator cuff and deltoid integrity, infection, subtle fractures, and nerve pathology are reviewed, with illustrative sample images. CONCLUSION: MRI is a valuable tool in the assessment for pathology in the shoulder following arthroplasty.

US of the elbow: indications, technique, normal anatomy, and pathologic conditions.

The elbow, a synovial hinge joint, is a common site of disease. Ultrasonography (US) has become an important imaging modality for evaluating pathologic conditions of the elbow. This powerful imaging tool has the advantages of outstanding spatial resolution, clinical correlation with direct patient interaction, dynamic assessment of disease, and the ability to guide interventions. Unlike most other imaging modalities, US allows the contralateral elbow to be imaged simultaneously, providing an internal control and comparison with normal anatomy. A useful approach to US evaluation of the elbow is to divide it into four compartments: anterior, lateral, medial, and posterior. US of the elbow has varied clinical applications, including evaluation and treatment of lateral and medial epicondylitis, imaging of biceps and triceps musculotendinous injuries, evaluation of ulnar collateral ligament laxity, diagnosis of joint effusions and intraarticular bodies, and evaluation of peripheral nerves for neuropathy and subluxation. US can also be used to evaluate soft-tissue masses about the elbow. Knowledge of the normal US anatomy of the elbow, familiarity with the technique of elbow US, and awareness of the US appearances of common pathologic conditions of the elbow along with their potential treatment options will optimize radiologists' diagnostic assessment and improve patient care. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.334125059/-/DC1.

Epicondylitis: pathogenesis, imaging, and treatment.

Epicondylitis commonly affects the elbow medially or laterally, typically in the 4th or 5th decade of life and without predilection with regard to sex. Epicondylitis is an inflammatory process that may be more accurately described as tendinosis. In the lateral epicondylar region, this process affects the common extensor tendon; in the medial epicondylar region, the common flexor tendon is affected. The condition is widely believed to originate from repetitive overuse with resultant microtearing and progressive degeneration due to an immature reparative response. Advances in understanding of the anatomy and pathophysiology of epicondylitis have shaped current treatment practices. Conservative measures are undertaken initially, because symptoms in most patients improve with time and rest. Those who fail to respond to conservative therapy are considered for surgical treatment. When surgery is contemplated, magnetic resonance imaging or ultrasonography is useful for evaluating the extent of disease, detecting associated pathologic processes, excluding other primary sources of elbow pain, and planning the surgical approach. Familiarity with the normal anatomy, the pathophysiology of epicondylitis and its mimics, and diagnostic imaging techniques and findings allows more accurate diagnosis and helps establish an appropriate treatment plan.

The ambiguous pulmonary venoatrial junction: a new perspective.

PURPOSE: The pulmonary venoatrial junction (PVAJ) has recently received attention due to the widespread use of catheter ablation for atrial fibrillation. However, the literature lacks a consensus in the definition of the PVAJ. We aim to review the inconsistent definitions for the PVAJ and related implications in imaging and catheter ablation for atrial fibrillation. RESULTS: The PVAJ as described by embryology, gross anatomy, histology and imaging is ambiguous, leading to disparities in its definition. Because of differing definitions of the PVAJ, there is a broad range in the prevalence of anatomic variations, including (1) percentage of common pulmonary veins (10-79% on the left), (2) supernumerary pulmonary veins (10-42%) and (3) ostial diameter and shape. We postulate several reasons for this broad range in the described prevalence of anatomic variation of the PV as follows: (1) different definitions of the PVAJ, (2) different vantage points, (3) different imaging modalities, and (4) different prevalence of anatomic variants among different study populations. CONCLUSIONS: The ambiguous PVAJ with its gradual transition from the left atrium to the pulmonary veins defies precise definition even though it plays an important role in the management of atrial fibrillation. Physicians should be aware of variability in the language used to describe the PVAJ and resultant discrepancy in reported anatomical information.