Comparison of MRI and arthroscopy findings for transitional zone cartilage damage in the acetabulum of the hip joint

OBJECTIVE

To assess the performance of morphologic and hypointense signal changes on MRI to predict grades and types of acetabular cartilage damage in the chondrolabral transitional zone (TZ) of the hip identified at arthroscopy.

MATERIALS AND METHODS

This retrospective single-center study reviewed conventional 3T MRI hip studies from individuals with symptomatic femoroacetabular impingement (FAI) and subsequent hip arthroscopy surgery within 6 months. Independent review was made by three radiologists for the presence of morphologic damage or a hypointense signal lesion in the TZ on MRI. Fleiss' kappa statistic was used to assess inter-reader agreement. The degree of TZ surfacing damage (modified Outerbridge grades 1-4) and presence of non-surfacing wave sign at arthroscopic surgery were collected. Relationship between sensitivity and lesion grade was examined.

RESULTS

One hundred thirty-six MRI hip studies from 40 males and 74 females were included (mean age 28.5 years, age range 13-54 years). MRI morphologic lesions had a sensitivity of 64.9-71.6% and specificity of 48.4-67.7% for arthroscopic surfacing lesions, with greater sensitivity seen for higher grade lesions. Low sensitivity was seen for wave sign lesions (34.5-51.7%). MRI hypointense signal lesions had a sensitivity of 26.3-62% and specificity of 43.8-78.0% for any lesion. Inter-reader agreement was moderate for morphologic lesions (k = 0.601) and poor for hypointense signal lesions (k = 0.097).

CONCLUSION

Morphologic cartilage damage in the TZ on MRI had moderate sensitivity for any cartilage lesion, better sensitivity for higher grade lesions, and poor sensitivity for wave sign lesions. The diagnostic value of hypointense signal lesions was uncertain.

Anatomical Proximity Between Sciatic Nerve and Ischial Spine and its Relationship to the Development of Deep Gluteal Pain Syndrome

OBJECTIVE

Deep gluteal syndrome (DGS) is a medical diagnosis in which the pathoanatomy of the subgluteal space contributes to pain. The growing recognition that gluteal neuropathies can be associated with the presence of a bone-neural conflict with irritation or compression may allow us to shed some light on this pathology. This study aims to determine whether the location of the sciatic nerve in relation to the ischial spine contributes to the development of DGS.

METHODS

The sciatic nerve - ischial spine relationship was analyzed based on magnetic resonance imaging (MRI) in 15 surgical patients who underwent piriformis release, and in 30 control patients who underwent MRI of the pelvis for reasons unrelated to sciatica. The sciatic nerve exit from the greater sciatic foramen was classified as either zone A (medial to the ischial spine); zone B (on the ischial spine); or zone C (lateral to the ischial spine).

RESULTS

The sciatic nerve was significantly closer to the ischial spine in surgical patients than in MRI controls (P=0.014). When analyzing patients of similar age, sciatic nerves in surgical patients were significantly closer (P=0.0061) to the ischial spine, and located in zone B significantly more (P=0.0216) as compared to MRI controls. Patients who underwent surgery for piriformis release showed a significant decrease in pain postoperatively (P<0.0001).

CONCLUSIONS

The results from this study suggest that the relationship between the ischial spine and sciatic nerve may play a role in the development of DGS. This may also help establish which patients would benefit more from surgical intervention.

ACR Appropriateness Criteria® Imaging After Total Knee Arthroplasty: 2023 Update

Total knee arthroplasty is the most commonly performed joint replacement procedure in the United States. This manuscript will discuss the recommended imaging modalities for six clinical variants; 1. follow-up of symptomatic or asymptomatic patients with a total knee arthroplasty. Initial imaging, 2. Suspected infection after total knee arthroplasty. Additional imaging following radiographs, 3. Pain after total knee arthroplasty. Infection excluded. Suspect aseptic loosening or osteolysis or instability. Additional imaging following radiographs, 4. Pain after total knee arthroplasty. Suspect periprosthetic or hardware fracture. Additional imaging following radiographs, 5. Pain after total knee arthroplasty. Measuring component rotation. Additional imaging following radiographs, and 6. Pain after total knee arthroplasty. Suspect periprosthetic soft-tissue abnormality unrelated to infection, including quadriceps or patellar tendinopathy. Additional imaging following radiographs. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Imaging After Total Hip Arthroplasty

This article reviews evidence for performing various imaging studies in patients with total hip prostheses. Routine follow-up is generally performed with radiography. Radiographs are also usually the initial imaging modality for patients with symptoms related to the prosthesis. Following acute injury with pain, noncontrast CT may add information to radiographic examination regarding the presence and location of a fracture, component stability, and bone stock. Image-guided joint aspiration, noncontrast MRI, and white blood cell scan and sulfur colloid scan of the hip, are usually appropriate studies for patients suspected of having periprosthetic infection. For evaluation of component loosening, wear, and/or osteolysis, noncontrast CT or MRI are usually appropriate studies. Noncontrast MRI is usually appropriate for identifying adverse reaction to metal debris related to metal-on-metal articulations. For assessing patients after hip arthroplasty, who have trochanteric pain and nondiagnostic radiographs, ultrasound, or MRI are usually appropriate studies. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Chronic Hip Pain: 2022 Update

Chronic hip pain is a frequent chief complaint for adult patients who present for evaluation in a variety of clinical practice settings. Following a targeted history and physical examination, imaging plays a vital role in elucidating the etiologies of a patient's symptoms, as a wide spectrum of pathological entities may cause chronic hip pain. Radiography is usually the appropriate initial imaging test following a clinical examination. Depending on the clinical picture, advanced cross-sectional imaging may be subsequently performed for further evaluation. This documents provides best practice for the imaging workup of chronic hip pain in patients presenting with a variety of clinical scenarios. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Chronic Extremity Joint Pain-Suspected Inflammatory Arthritis, Crystalline Arthritis, or Erosive Osteoarthritis: 2022 Update

Evaluation for suspected inflammatory arthritis as a cause for chronic extremity joint pain often relies on imaging. It is essential that imaging results are interpreted in the context of clinical and serologic results to add specificity because there is significant overlap of imaging findings among the various types of arthritis. This document provides recommendations for imaging evaluation of specific types of inflammatory arthritis, including rheumatoid arthritis, seronegative spondyloarthropathy, gout, calcium pyrophosphate dihydrate disease (or pseudogout), and erosive osteoarthritis. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Chronic Shoulder Pain: 2022 Update

Chronic shoulder pain is an extremely common presenting complaint. Potential pain generators include the rotator cuff tendons, biceps tendon, labrum, glenohumeral articular cartilage, acromioclavicular joint, bones, suprascapular and axillary nerves, and the joint capsule/synovium. Radiographs are typically the initial imaging study obtained in patients with chronic shoulder pain. Further imaging may often be required, with modality chosen based on patient symptoms and physical examination findings, which may lead the clinician to suspect a specific pain generator. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Osteoporosis and Bone Mineral Density: 2022 Update

Osteoporosis constitutes a significant public health risk. An estimated 10.2 million adults in the United States >50 years of age have osteoporosis, a systemic condition that weakens the bones increasing the susceptibility for fractures. Approximately one-half of women and nearly one-third of men >50 years of age will sustain an osteoporotic fracture. These fractures are associated with a decrease in quality of life, diminished physical function, and reduced independence. Dual-energy X-ray absorptiometry (DXA) is the primary imaging modality used to screen for osteoporosis in women >65 years of age and men >70 years of age. DXA may be used in patients <65 years of age to evaluate bone mass density if there are additional risk factors. In certain situations, vertebral fracture assessment and trabecular bone score may further predict fracture risk, particularly in patients who are not yet osteoporotic but are in the range of osteopenia. Quantitative CT is useful in patients with advanced degenerative changes in the spine. Given the proven efficacy of pharmacologic therapy, the role of imaging to appropriately identify and monitor high-risk individuals is critical in substantially reducing osteoporosis-associated morbidity and mortality, and reducing the considerable cost to the health care system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Contrast-enhanced ultrasound-guided musculoskeletal biopsies: our experience and technique

OBJECTIVE

To present our experience with contrast-enhanced ultrasound (CEUS)-guided musculoskeletal soft tissue biopsies in a busy interventional clinic.

MATERIALS AND METHODS

After IRB approval was obtained and informed consent was waived, we retrospectively reviewed all CEUS-guided musculoskeletal biopsies performed from December 1, 2018 to March 2, 2020. Relevant pre-procedure imaging was reviewed. Number of samples, suspected necrosis on pre-procedure imaging, specimen adequacy for pathologic analysis, correlation with pathologic diagnosis of surgical resection specimens, and procedural complications were recorded.

RESULTS

Thirty-six CEUS-guided musculoskeletal biopsies were performed in 32 patients (mean age 57, range 26-88; 22 males, 10 females). All procedures were performed using 16-gauge biopsy needles, and all procedures provided adequate samples for pathologic analysis as per the final pathology report. Between two and seven core specimens were obtained (mean 3.7). In 30/36 cases (83%), a contrast-enhanced MRI was obtained prior to biopsy, and 10/30 (33%) of these cases showed imaging features suspicious for necrosis. In 15/36 cases, surgical resection was performed, and the core biopsy and surgical resection specimens were concordant in 14/15 cases (93%). One patient noted transient leg discomfort at the time of microbubble bursting. Otherwise, no adverse reactions or procedural complications were observed.

CONCLUSION

CEUS is an accurate way to safely target representative areas of soft tissue lesions for biopsy and can be implemented in a busy interventional clinic. Our early experience has shown this to be a promising technique, especially in targeting representative areas of heterogeneous lesions and lesions with areas of suspected necrosis on prior imaging.

Microinstability of the hip: a systematic review of the imaging findings

OBJECTIVES

To undertake a systematic review of the morphologic features associated with hip microinstability and determine whether there are suggestive or diagnostic imaging findings.

METHODS

Four electronic databases were searched up to September 2019 to identify original research reporting morphologic features in individuals with either a clinical diagnosis of hip microinstability (instability without overt subluxation/dislocation) or those with symptomatic laxity demonstrated on imaging (increased femoral head translation/distraction or capsular volume). Studies focussing on individuals with pre-existing hip conditions (including definite dysplasia (lateral centre edge angle < 20°), significant trauma, previous dislocation or surgery were excluded. Methodological quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

RESULTS

Twenty-two studies met inclusion criteria (clinical diagnosis of microinstability n = 15 and demonstration of laxity n = 7). Imaging information gathered from the studies includes radiographs (n = 14), MRI (n = 6), MR arthrography (n = 4), CT (n = 1) and intraoperative examination. Most studies exhibited design features associated with an overall high or unclear risk of bias. Some dysplastic features are associated with microinstability or laxity reference measures; however, microinstability is frequently diagnosed in those with a lateral centre edge angle > 25°. Other associated imaging findings reported include impingement morphology, anterior labral tearing, femoral head chondral injury, ligamentum teres tears and capsular attenuation.

CONCLUSIONS

The current literature does not provide strong evidence for imaging features diagnostic of microinstability. In the appropriate clinical context, dysplastic morphology, anterior labral tears and ligamentum teres tears may be suggestive of this condition although further research is needed to confirm this.

PROSPERO REGISTRATION

CRD42019122406.

Incidence and implications of fracture in core muscle injury

OBJECTIVE

To determine the pubic bone fracture incidence and associated injury patterns in patients with core muscle injury.

MATERIALS AND METHODS

Ninety-three consecutive patients with core muscle injury protocol MRI showing rectus abdominis-adductor longus aponeurotic plate injuries from June 2007 through August 2017 were independently analyzed in blinded fashion by two musculoskeletal radiologists for the presence or absence of pubic bone fracture. A variety of other osseous and soft tissue injury characteristics were recorded. Pain duration prior to MRI and return to play time were taken from the clinical record. Statistical analysis included fracture incidence as well as the association of fracture with other injury characteristics, duration of pain, and return to play time.

RESULTS

Eighty-seven men and six women with a mean age of 34.4 years (range, 16-66 years) were included in the study cohort. Overall fracture incidence was 18.3% (17/93) including 13 fatigue fractures of the pubic body and four elevated cortical fractures/fragments. After correction for multiple comparisons, no strong association was identified with osseous or soft tissue injury characteristics, pain duration, or return to play time.

CONCLUSIONS

Pubic fractures-particularly fatigue fractures-are a common co-existing injury in patients with a wide range of core muscle injury patterns. The presence of fracture did not have a strong correlation with injury patterns, pain duration, or return to play time but may have implications for patient management.

Overuse Injuries of the Shoulder

This article discusses the most common and important overuse injuries of the shoulder with attention to MR imaging and ultrasound findings. Pathologic conditions occurring in athletes and nonathletes are included, with review of relevant anatomy, predisposing factors, and treatment considerations. Specific overuse injuries involving the rotator cuff, long head of the biceps tendon, and subacromial-subdeltoid bursa are reviewed. Impingement syndromes of the shoulder, Little Leaguer's shoulder, and stress-induced distal clavicular osteolysis are also discussed.

Juvenile Osteochondritis Dissecans: Cartilage T2 Mapping of Stable Medial Femoral Condyle Lesions

Purpose To determine whether a T2 mapping sequence could depict early changes in the composition and microstructure of cartilage overlying stable lesions of the medial femoral condyle in patients with juvenile osteochondritis dissecans (JOCD). Materials and Methods This retrospective study analyzed a sagittal T2 mapping sequence performed between September 1, 2015, and March 31, 2017, on 16 patients (10 boys and six girls; median age, 11.5 years) with 18 stable medial femoral condyle JOCD lesions and 18 age-, sex-, and skeletal maturation-matched control participants (11 boys and seven girls; median age, 11.5 years). Cartilage T2 values were quantitatively measured within regions of interest placed around the cartilage within and overlying the JOCD lesion in patients with JOCD and around the cartilage on the weight-bearing medial femoral condyle in patients with JOCD and controls. Wilcoxon signed rank and Wilcoxon rank sum tests were used to compare T2 values. Results T2 values were significantly higher (P < .001) for cartilage within the JOCD lesion than for cartilage overlying the JOCD lesion in patients with JOCD. However, there were no significant differences in T2 values between cartilage overlying the JOCD lesion and cartilage on the weight-bearing medial femoral condyle in patients with JOCD (P = .67) or in T2 values of the cartilage on the weight-bearing medial femoral condyle between patients with JOCD and controls (P = .30). Conclusion There were no significant quantifiable differences in T2 values of cartilage overlying stable JOCD lesions and normal cartilage on the medial femoral condyle, suggesting no substantial changes in cartilage composition and microstructure.

Magnetic Resonance Imaging Appearance of the Hip Musculature After Arthroscopic Labral-Level Iliopsoas Tenotomies

BACKGROUND

Iliopsoas (IP) muscle atrophy is a known consequence of open IP tenotomy, but the severity of IP muscle atrophy that occurs after arthroscopic labral-level IP tenotomies has not been documented.

PURPOSE

To document the severity of muscle atrophy that occurs in the iliacus, psoas, and adjacent hip musculature after arthroscopic labral-level IP tenotomy.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-eight patients who had magnetic resonance arthrograms (MRAs) obtained prior to and 3 months to 5 years after arthroscopic labral-level IP tenotomies are the basis of this report. The pre- and postoperative MRAs of each patient were examined in consensus by 2 musculoskeletal radiologists who graded the postoperative muscle atrophy from 0 (no fatty infiltration) to 4 (>75% fatty infiltration) and noted any compensatory muscle hypertrophy or abnormal IP tendon morphology. Patients also were assessed with the Byrd 100-point modified Harris Hip Scoring system (MHHS) preoperatively and at the time of their postoperative MRA.

RESULTS

Postoperative MRAs were obtained on average 1.7 years (range, 3 months to 5 years) after hip arthroscopy. None of the patients had muscle atrophy on their preoperative MRAs. In contrast, 89% of patients had iliacus and psoas muscle atrophy on their postoperative MRAs, but only 2 (7%) developed grade 4 atrophy, and the majority (64%) had either grade 1 (n = 15) or no atrophy (n = 3). In addition, there were no significant differences in the MHHS of the patients with mild (grades 0-1), moderate (grades 2-3), or severe (grade 4) postoperative atrophy. Postoperative MRAs also demonstrated low-grade atrophy (grades 1-2) in the quadratus femoris (n = 5) and rectus femoris (n = 1) muscles, and 16 patients (57%) had distortion of the tendon, but none had a gap in their tendon.

CONCLUSION

A majority of patients (89%) developed IP muscle atrophy after arthroscopic labral-level IP tenotomies, and although this percentage was similar (89% vs 90%) to that reported with lesser trochanteric IP tenotomies, the patients did not (1) develop atrophy of the gluteus maximus and vastus lateralis muscles, (2) have chronic IP tendon disruption, or (3) develop the severity of IP atrophy (55% grade 4 vs 7% grade 4) that has been reported after arthroscopic lesser trochanteric IP tenotomies.

Rapid in vivo multicomponent T2 mapping of human knee menisci

PURPOSE

To compare multicomponent T2 parameters of menisci measured using Multicomponent Driven Equilibrium Single Pulse Observation of T1 and T2 (mcDESPOT) in asymptomatic volunteers and osteoarthritis (OA) patients with intact and torn menisci.

MATERIALS AND METHODS

The prospective study was performed with Institutional Review Board approval and with all subjects signing written informed consent. mcDESPOT was performed on the knee joint of 12 asymptomatic volunteers and 14 patients with knee OA. Single-component T2 relaxation time (T2Single ), T2 relaxation time of the fast relaxing water component (T2F ), and the slow relaxing water component (T2S ), and fraction of the fast relaxing water component (FF ) of the medial and lateral menisci were measured. Multivariate linear regression models were used to compare mcDESPOT parameters between normal menisci in asymptomatic volunteers, intact menisci in OA patients, and torn menisci in OA patients with adjustment for differences in age between subjects.

RESULTS

The mean mcDESPOT parameters for normal menisci in asymptomatic volunteers, intact menisci in OA patients, and torn menisci in OA patients were respectively 16.1 msec, 18.8 msec, and 22.7 msec for T2Single ; 9.0 msec, 10.0 msec, and 11.1 msec for T2F ; 24.4 msec, 27.7 msec, and 31.4 msec for T2S ; and 34%, 32%, 27% for FF . There were significant differences (P < 0.05) in T2Single , T2F , T2S , and FF between the three groups of menisci.

CONCLUSION

The menisci of OA patients had significantly higher T2Single , T2F , and T2S and significantly lower FF than normal menisci in asymptomatic volunteers with greater changes in multicomponent T2 parameters noted in torn than intact menisci in OA patients.

MR Appearance and Clinical Significance of Changes in the Hip Muscles and Iliopsoas Tendon After Arthroscopic Iliopsoas Tenotomy in Symptomatic Patients

BACKGROUND

Iliopsoas tenotomy is a treatment for snapping hip. Does this surgical procedure change the surrounding muscle and tendon anatomy?

QUESTIONS/PURPOSES

This study seeks to evaluate the changes in the MR appearance of the hip muscles and iliopsoas tendon in patients following arthroscopic iliopsoas tenotomy.

METHODS

One hundred sixty-nine consecutive adults were evaluated after iliopsoas tenotomy at the lesser trochanter. Each MR exam was evaluated independently by three radiologists for muscle edema, atrophy (grade 0-4), compensatory hypertrophy, signal within the iliopsoas tendon (increased on T1 or T2 sequences), and iliopsoas tendon morphology (distorted or disrupted) above, at, and below the iliopectineal eminence. A finding was considered positive if reported by two or three of the radiologists.

RESULTS

Twenty subjects met the inclusion criteria. Muscle edema was present in 15% (3/20) of subjects within the iliacus, psoas, and quadratus femoris. Atrophy was observed in the following muscles: iliacus 85% (17/20), psoas 75% (15/20), quadratus femoris 10% (2/20), rectus femoris 5% (1/20), vastus lateralis 5% (1/20), and gluteus maximus 25% (5/20). There was no compensatory hypertrophy. Ninety percent (18/20) had increased T1 and 10% (2/20) had increased T2 signal within the iliopsoas tendon. Thirty-five percent (7/20) of the iliopsoas tendons was disrupted and 85% (17/20) was distorted, most commonly below the iliopectineal eminence.

CONCLUSION

The majority of postoperative symptomatic patients has atrophy of the iliacus and psoas muscles and distortion and disruption of the iliopsoas tendon and should be recognized as a normal imaging appearance following iliopsoas tendon release.

Non-femoroacetabular impingement

Femoroacetabular impingement is one of the causes of hip pain leading to acetabular labral tears and cartilage damage that may lead to the development of early osteoarthritis. More recently other causes of impingement have been recognized that may be the culprit for the painful hip. These causes include ischiofemoral, anterior inferior iliac spine/subspine and iliopsoas impingement. Ischiofemoral impingement syndrome is related to narrowing between the ischial tuberosity and lesser trochanter with abnormalities of the quadratus femoris muscle producing hip pain. Anterior inferior iliac spine/subspine impingement syndrome is defined as hip pain produced by abnormal contact between the anterior inferior iliac spine and proximal femur. Iliopsoas impingement may produce hip pain that is related to a thickened or taut iliopsoas tendon at the level of the acetabular rim/anterior hip capsule. Radiographs, magnetic resonance imaging, ultrasound, or computed tomography may help to better elucidate the problem while excluding intra-articular pathology or femoroacetabular impingement. Keeping these causes of impingement in mind when evaluating the painful hip will aid in diagnosis.

Evaluation of the menisci of the knee joint using three-dimensional isotropic resolution fast spin-echo imaging: diagnostic performance in 250 patients with surgical correlation

OBJECTIVE

To compare the diagnostic performance of FSE-Cube, a three-dimensional isotropic resolution intermediate-weighted fast spin-echo sequence, with a routine magnetic resonance (MR) protocol at 3.0 T for detecting surgically confirmed meniscal tears of the knee joint in a large patient population.

METHODS

FSE-Cube was added to a routine MR protocol performed at 3.0 T on 250 patients who underwent subsequent knee arthroscopy. Three radiologists independently used FSE-Cube during one review and the routine MR protocol during a second review to detect medial and lateral meniscal tears. Using arthroscopy as the reference standard, the sensitivity and specificity of FSE-Cube and the routine MR protocol for detecting meniscal tears were determined for all readers combined. McNemar's tests were used to compare diagnostic performance between FSE-Cube and the routine MR protocol.

RESULTS

FSE-Cube and the routine MR protocol had similar sensitivity (95.5%/95.3% respectively, P = 0.94) and similar specificity (69.8%/74.0% respectively, P = 0.10) for detecting 156 medial meniscal tears. FSE-Cube had significantly lower sensitivity than the routine MR protocol (79.4%/85.0% respectively, P < 0.05) but similar specificity (83.9%/82.2% respectively, P = 0.37) for detecting 89 lateral mensical tears. For lateral meniscal tears, FSE-Cube had significantly lower sensitivity (P < 0.05) than the routine MR protocol for detecting 19 root tears but similar sensitivity (P = 0.17-1.00) for detecting all other tear locations and types.

CONCLUSION

FSE-Cube had diagnostic performance similar to a routine MR protocol for detecting meniscal tears except for a significantly lower sensitivity for detecting lateral meniscal tears, which was mainly attributed to decreased ability to identify lateral meniscus root tears.

MR imaging of early hip joint degeneration

MR imaging is one of the most commonly used imaging techniques to evaluate patients with hip pain. Intra-articular abnormalities of the hip joint are better assessed with recent advances in MR imaging technology, such as high-field strength scanners, improved coils, and more signal-to-noise ratio-efficient sequences. This article discusses the causes of early hip joint degeneration and the current use of morphologic and physiologic MR imaging techniques for evaluating the articular cartilage of the hip joint. The article also discusses the role of MR arthrography in clinical cartilage imaging.

Hip pain referral patterns in patients with labral tears: analysis based on intra-articular anesthetic injections, hip arthroscopy, and a new pain "circle" diagram

BACKGROUND

Fluoroscopically guided intra-articular (FGIA) anesthetic hip joint injections have been used to determine whether the hip joint is the source of a patient's hip pain. However, there have been no reports documenting the efficacy of their use for defining the pain referral patterns (PRPs) of patients with labral tears. The aim of this study was to determine the PRPs of patients with labral tears and evaluate a new pain "circle" diagram (PCD) developed for this analysis.

METHODS

Fifty-two patients were evaluated at our institution who had: 1) a preoperative FGIA anesthetic hip joint injection; 2) completed our PCD and a visual analog pain scale pre- and postinjection; 3) significant (≥ 80%) pain reduction after their FGIA injection; and 4) a labral tear and minimal (≤ grade II) degenerative joint disease, as documented by hip arthroscopy. The PCD had circles in which patients put an "X" in to indicate pain in the following locations: anterior superior spine, lateral peritrochanteric area, central groin, symphysis pubis, proximal inner thigh, anterior thigh, posterior iliac crest, sacroiliac joint, sciatic notch, and ischial tuberosity.

RESULTS

Based on the percentage of patients with significant (≥ 80%) pain reduction after administration of FGIA, 2 areas demonstrated substantially more and consistent presence of pain, which improved after injection. These were the central groin (P < 0.001) and the lateral peritrochanteric area (P = 0.02).

CONCLUSION

The most common locations of pain were the central groin and the lateral peritrochanteric area. The least common were the ischial tuberosity and the anterior thigh, which are 2 areas often associated with osteoarthritis of the hip. The use of the PCD combined with an FGIA anesthetic injection may help physicians reconcile the expectations of those patients with labral tears who believe that hip arthroscopy will treat their multiple areas of "hip" pain.

Musculoskeletal mnemonics: differentiating features

Mnemonics are often used in musculoskeletal radiology to help radiologists remember long differential diagnoses. However, unless the specific appearance of each entity on a differential is also recalled, mnemonics become useless. This article presents 8 mnemonics with their corresponding differential diagnoses and distinguishing features. Bubbly lucent lesions of bone are recalled with the FEGNOMASHIC mnemonic, but when only lucent lesions of the diaphysis are included, a more appropriate mnemonic is FEMALE. The lucent lesions of bone differentials often can be narrowed based on specific characteristics of the lesion but radiographic findings elsewhere and clinical information often help. Osseous metastases may present as lucent or sclerotic lesions; when sclerotic, the differential is best remembered with the mnemonic 5 "BEES" Like Pollen. The mnemonic for Wormian bones is PORKCHOPS. The Wormian bones in most of these entities are indistinguishable, so one must rely on radiographic findings outside the skull for diagnosis. By contrast, differentiating causes of acro-osteolysis is often possible with findings seen only on the hand radiographs; the mnemonic for acro-osteolysis is RADSHIP. In skeletally immature patients with frayed metaphyses, the mnemonic is CHARMS. Although the appearance of the fraying is seldom diagnostic, findings in the adjacent portions of the long bones may be characteristic. FETISH is the mnemonic used to remember the entities for the differential diagnosis of vertebra plana. Age of the patient, clinical history, and findings in the adjacent spine often help to provide the specific diagnosis. Nearly all the entities on the differential diagnosis for distal clavicle erosion (mnemonic: SHIRT Pocket) are included in other differentials in this article.

Correlation of MRI findings with clinical findings of trochanteric pain syndrome

OBJECTIVE

Greater trochanter pain syndrome due to tendinopathy or bursitis is a common cause of hip pain. The previously reported magnetic resonance (MR) findings of trochanteric tendinopathy and bursitis are peritrochanteric fluid and abductor tendon abnormality. We have often noted peritrochanteric high T2 signal in patients without trochanteric symptoms. The purpose of this study was to determine whether the MR findings of peritrochanteric fluid or hip abductor tendon pathology correlate with trochanteric pain.

MATERIALS AND METHODS

We retrospectively reviewed 131 consecutive MR examinations of the pelvis (256 hips) for T2 peritrochanteric signal and abductor tendon abnormalities without knowledge of the clinical symptoms. Any T2 peritrochanteric abnormality was characterized by size as tiny, small, medium, or large; by morphology as feathery, crescentic, or round; and by location as bursal or intratendinous. The clinical symptoms of hip pain and trochanteric pain were compared to the MR findings on coronal, sagittal, and axial T2 sequences using chi-square or Fisher's exact test with significance assigned as p < 0.05.

RESULTS

Clinical symptoms of trochanteric pain syndrome were present in only 16 of the 256 hips. All 16 hips with trochanteric pain and 212 (88%) of 240 without trochanteric pain had peritrochanteric abnormalities (p = 0.15). Eighty-eight percent of hips with trochanteric symptoms had gluteus tendinopathy while 50% of those without symptoms had such findings (p = 0.004). Other than tendinopathy, there was no statistically significant difference between hips with or without trochanteric symptoms and the presence of peritrochanteric T2 abnormality, its size or shape, and the presence of gluteus medius or minimus partial thickness tears.

CONCLUSIONS

Patients with trochanteric pain syndrome always have peritrochanteric T2 abnormalities and are significantly more likely to have abductor tendinopathy on magnetic resonance imaging (MRI). However, although the absence of peritrochanteric T2 MR abnormalities makes trochanteric pain syndrome unlikely, detection of these abnormalities on MRI is a poor predictor of trochanteric pain syndrome as these findings are present in a high percentage of patients without trochanteric pain.

Arthroscopic treatment of the painful "internal" snapping hip: results of a new endoscopic technique and imaging protocol

BACKGROUND

Traditional surgical treatment for a painful snapping iliopsoas tendon has been an open lengthening of the tendon.

HYPOTHESIS

An endoscopic release will alleviate painful snapping of the tendon.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Six patients with painful snapping hips who had no pain relief after magnetic resonance arthrography, which included injection of bupivacaine into the hip joint, subsequently had an ultrasound evaluation of their iliopsoas tendons and an anesthetic injection into the psoas bursa. In all 6 patients, the injection relieved their hip pain, and in 4, real-time imaging demonstrated snapping of the tendon. All hips were evaluated with the 100-point Harris hip scoring system before and at 1.5, 3, 6, and 12 months after surgery.

RESULTS

Preoperative hip scores averaged 58 points. After surgery, all patients had hip flexor weakness, used crutches for 5 weeks, and had 6-week scores that averaged 62 points. The patients continued to improve, and at 6 and 12 months, their scores averaged 90 and 96 points, respectively, and none had recurrence of their snapping or pain.

CONCLUSION

Ultrasound-guided anesthetic injection of the psoas bursa is useful to confirm snapping of the iliopsoas tendon as the cause of a patient's hip pain. Endoscopic release of the tendon is a safe outpatient procedure that provides effective relief of the snapping and pain.

Classification and localization of acetabular labral tears

OBJECTIVE

The purpose of this study was to compare the findings on hip MR arthrography (MRA) with the published MRA and arthroscopic classifications of hip labral tears and to evaluate a clock-face method for localizing hip labral tears.

DESIGN/PATIENTS

We retrospectively reviewed 65 hip MRA studies with correlative hip arthroscopies. Each labrum was evaluated on MRA using the classification system of Czerny and an MRA modification of the Lage arthroscopic classification. In addition, each tear was localized on MRA by using a clock-face description where 6 o'clock was the transverse ligament and 3 o'clock was anterior. These MRA findings were then correlated with the arthroscopic findings using the clock-face method of localization and the Lage arthroscopic classification of labral tears.

RESULTS

At MRA, there were 42 Czerny grade 2 and 23 grade 3 labral tears and 22 MRA Lage type 1, 11 type 2, 22 type 3 and 10 type 4 tears. At arthroscopy, there were 10 Lage type 1 flap tears, 20 Lage type 2 fibrillated tears, 18 Lage type 3 longitudinal peripheral tears and 17 Lage type 4 unstable tears. The Czerny MRA classification and the modified MRA Lage classification had borderline correlation with the arthroscopic Lage classification. Localization of the tears using a clock-face description was within 1 o'clock of the arthroscopic localization of the tears in 85% of the patients.

CONCLUSIONS

The Lage classification, which is the only published arthroscopic classification system for hip labral tears, does not correlate well with the Czerny MRA or an MRA modification of the Lage classification. Using a clock-face description to localize tears provides a way to accurately localize a labral tear and define its extent.

Sonography of the iliopsoas tendon and injection of the iliopsoas bursa for diagnosis and management of the painful snapping hip

OBJECTIVE

The purpose of this study was to compare sonographic evaluations of patients referred with suspected snapping of their iliopsoas tendon with the pain relief achieved from anesthetic injection of the iliopsoas bursa, and with the subsequent surgical outcome. This study also assessed the effectiveness of Kenalog injection into the iliopsoas bursa for long-term pain relief.

PATIENTS AND METHODS

Dynamic and static sonography was performed in 40 patients with clinically diagnosed snapping hips. The iliopsoas bursa was injected with Bupivicaine and Lidocaine in the first 22 patients, and an additional 1 ml Kenalog-40 was added to this mixture in the last 18 patients. We compared the static and dynamic sonographic findings with change in the patients' level of pain at 2 days after anesthetic injection. The sonographic findings and response to anesthetic injection were also compared to the response to Kenalog injection and the results of any subsequent surgery.

RESULTS

Static sonography of the iliopsoas tendon was normal in 38 patients, and detected iliopsoas bursitis in one patient and iliopsoas tendinopathy in another. Snapping of the iliopsoas tendon was observed using dynamic sonography in 9 of the 40 patients. Following anesthetic injection of the iliopsoas bursa, 29 patients had complete or partial pain relief, and 11 patients had no pain relief. Eight of the nine patients with a snapping iliopsoas tendon had complete or partial pain relief from the bursal injection. Twelve of the 29 patients with pain relief after anesthetic injection later had an arthroscopic iliopsoas tendon release, and all of these 12 patients had a good postoperative result. Of the 18 patients who had Kenalog-40 injected into the iliopsoas bursa and did not have iliopsoas surgery, 16 had sustained pain relief following the injection.

CONCLUSIONS

Patients with groin pain and a clinically suspected snapping iliopsoas tendon can benefit from injection into the iliopsoas bursa even if the snapping tendon is not visualized sonographically. The use of a corticosteroid may provide long-term pain relief, and pain relief after injection is a predictor of good outcome after surgical release of the iliopsoas tendon.

The painful hip: new concepts

Hip pain is a common condition, and the work-up often includes imaging. This article reviews the normal MR anatomy of the hip and the imaging findings of internal derangements, snapping hip, and femoral acetabular impingement. We will describe the role of MR arthrography in evaluating the patient with suspected labral and articular cartilage abnormalities, as well as the pitfalls in interpretation. We will review the causes of a snapping hip, and the role of sonography in evaluating and guiding treatment of the snapping iliopsoas tendon. We will also review the radiographic and MRI signs of femoroacetabular impingement (FAI), a cause of early degenerative joint disease and hip pain.

Radiographic findings of osteoarthritis versus arthroscopic findings of articular cartilage degeneration in the tibiofemoral joint

PURPOSE

To retrospectively correlate radiographic findings of osteoarthritis of the tibiofemoral joint with arthroscopic findings of articular cartilage degeneration within the tibiofemoral joint in patients with chronic knee pain.

MATERIALS AND METHODS

The study was performed in compliance with HIPAA regulations. Approval from an institutional review board and a waiver of informed consent were obtained. The study group consisted of 125 patients with osteoarthritis of the tibiofemoral joint (66 men, 59 women; age range, 35-77 years; average age, 52 years) and 25 patients of similar age (14 men, 11 women; age range, 36-69 years; average age, 50 years) with no osteoarthritis of the tibiofemoral joint. All patients underwent standing anteroposterior radiography of the knee prior to arthroscopic knee surgery. Each articular surface of the tibiofemoral joint was graded at arthroscopy. Two radiologists retrospectively reviewed the knee radiographs to determine the presence of marginal osteophytes, joint space narrowing, subchondral sclerosis, and subchondral cysts. The sensitivity and specificity of the radiographic features of osteoarthritis for the detection of articular cartilage degeneration within the medial and lateral compartments of the tibiofemoral joint were determined.

RESULTS

The sensitivity of marginal osteophytes, joint space narrowing, subchondral sclerosis, and subchondral cysts for the detection of articular cartilage degeneration was 67%, 46%, 16%, and 10%, respectively, for the medial compartment and 49%, 7%, 6%, and 3%, respectively, for the lateral compartment. The specificity of marginal osteophytes, joint space narrowing, subchondral sclerosis, and subchondral cysts for the detection of articular cartilage degeneration was 73%, 95%, 100%, and 100%, respectively, for the medial compartment and 81%, 100%, 100%, and 100%, respectively, for the lateral compartment.

CONCLUSION

Marginal osteophytes were the most sensitive radiographic feature for the detection of osteoarthritis of the tibiofemoral joint. Joint space narrowing, subchondral sclerosis, and subchondral cysts were less sensitive radiographic features of osteoarthritis and rarely occurred in the absence of associated osteophyte formation.

Axial rotation of the lumbar spinal motion segments correlated with concordant pain on discography: a preliminary study

OBJECTIVE

One possible cause of back pain in patients with intervertebral disk degeneration is decreased stability of the motion segment. Axial rotations between lumbar spinal vertebrae can be measured noninvasively with CT. We tested the hypothesis that larger axial rotations are found in motion segments with disks that test positive for concordant pain, which is considered by some investigators to be a reasonable, accurate predictor of spinal instability.

SUBJECTS AND METHODS

Between October 2002 and March 2004, all patients undergoing discography were evaluated for inclusion in the study, with the approval of the institutional review board. All patients in whom concordant pain was detected at discography were enrolled in the study. The patients were placed supine in the CT scanner on a table that rotated the pelvis 8 degrees clockwise and then counterclockwise with respect to the thorax. CT images were obtained with the patient in the two positions of rotation. An automated program calculated the amount of rotation between each lumbar vertebra as a result of the table rotations. Rotations were stratified by disk level and by disk classification (concordant pain, nonconcordant pain, no significant pain).

RESULTS

We recorded the axial rotations of 94 disks in 16 consecutive patients (10 women, six men; age range, 26-53 years) after two disks were excluded because of a previous fusion. There were 68 normal disks by MRI and discography, six disks with nonconcordant pain, and 20 disks with concordant pain. Rotation averaged 0.6 degrees for the normal disks, 1.4 degrees for disks with nonconcordant pain, and 1.8 degrees for disks with concordant pain. The differences were significant (analysis of variance, p < 0.001). Disks at L3-L4 with concordant pain rotated on average 1.2 degrees , whereas disks classified as normal or nonconcordant pain rotated on average 0.7 degrees (significant at p = 0.005). Disks at L4-L5 with concordant pain rotated on average 1.9 degrees , and those without concordant pain rotated on average 1.4 degrees (significant at p = 0.05). Disks with concordant pain at L5-S1 had an average rotation of 2.2 degrees , whereas disks without concordant pain had an average rotation of 1.5 degrees (marginally significant difference at p = 0.07).

CONCLUSION

Concordant pain at discography predicts increased axial rotation at a lumbar disk level.

Lumbar Radiculopathy: Treatment with Selective Lumbar Nerve Blocks—Comparison of Effectiveness of Triamcinolone and Betamethasone Injectable Suspensions

PURPOSE

To retrospectively determine if there is a difference in the effectiveness of triamcinolone acetonide injectable suspension versus betamethasone sodium phosphate and betamethasone acetate injectable suspension in the treatment of radiculopathy and low back pain with selective lumbar nerve blocks.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and was HIPAA compliant; informed consent was not required. Charts and self-reported pain score evaluations were retrospectively reviewed in 114 patients (56 men, 58 women; age range, 36-84 years; mean age, 60 years) treated for radiculopathy from 1997 to 2003 with 130 selective lumbar nerve blocks with triamcinolone or betamethasone. Perineural location was confirmed with fluoroscopic guidance. Forty-nine patients received a mixture of 1 mL of the triamcinolone, 40 mg/mL, and 1 mL of 0.5% bupivacaine hydrochloride. Eighty-one patients received a mixture of 1 mL of the betamethasone, 6 mg/mL, and 1 mL of 0.5% bupivacaine hydrochloride. Patients completed standardized pain evaluation sheets and compared their pain with baseline levels during 14 days after injection. Fisher exact test was used for data analysis.

RESULTS

From day 0 to 1 after the procedure, there was no statistically significant difference in improvement in low back pain and lower extremity pain between groups. On day 3, 42% of triamcinolone recipients and 58% of betamethasone recipients demonstrated improvement in low back pain (P = .04, Fisher exact test), whereas 55% of triamcinolone recipients and 57% of betamethasone recipients had lower extremity pain improvement (P = .33). On day 7, 45% of triamcinolone recipients and 58% of betamethasone recipients had improvement in low back pain (P = .38), whereas 52% of triamcinolone recipients and 57% of betamethasone recipients had improvement in lower extremity pain (P = .69). On day 14, 42% of triamcinolone recipients and 53% of betamethasone recipients had improvement in low back pain (P = .26), whereas 49% of triamcinolone recipients and 55% of betamethasone recipients had improvement in lower extremity pain (P = .69).

CONCLUSION

Selective nerve root blocks with betamethasone and triamcinolone reduced low back pain and lower extremity pain, although there was no significant difference in effectiveness between the two.

Is intra-articular pathology associated with MCL edema on MR imaging of the non-traumatic knee?

OBJECTIVE

Edema surrounding the medial collateral ligament (MCL) is seen on MR imaging in patients with MCL injuries and in patients with radiographic osteoarthritis in the non-traumatic knee. Because we noted MCL edema in patients without prior trauma or osteoarthritis, we studied the association between intra-articular pathology and MCL edema in patients without knee trauma.

DESIGN AND PATIENTS

We evaluated the MR examinations of 247 consecutive patients (121 male, 126 female with a mean age of 44 years) without recent trauma for the presence of edema surrounding the MCL, meniscal and ACL tears, medial meniscal extrusion, medial compartment chondromalacia, and osteoarthritis. The percentages of patients illustrating MCL edema with and without each type of pathology were compared using Fisher's exact test to determine if there was a statistically significant association.

RESULTS

We found MCL edema in 60% of 247 patients. MCL edema was present in 67% of patients with medial meniscal tears, 35% with lateral meniscal tears, 100% with meniscal extrusion of 3 mm or more, 78% with femoral chondromalacia, 82% with tibial chondromalacia, and 50% with osteoarthritis. The percentage of patients with edema increased with the severity of the chondromalacia. These associations were all statistically significant (p <0.02). The mean age of those with MCL edema was 49.7 years compared with 34.9 years without MCL edema ( p <0.001). Patient gender and ACL tear did not correlate with MCL edema. Nine (4%) of the 247 patients had MCL edema without intra-articular pathology. None of these 9 patients had MCL tenderness or joint laxity on physical examination.

CONCLUSIONS

We confirmed that MCL edema is associated with osteoarthritis, but is also associated with meniscal tears, meniscal extrusion, and chondromalacia. In addition, MCL edema can be seen in patients without intra-articular pathology, recent trauma or MCL abnormality on physical examination.

Selective nerve root blocks

Selective nerve root blocks are valuable diagnostic and therapeutic procedures in patients with radicular symptoms. Understanding the anatomy, benefits, and risks, as well as precise needle placement, are important factors in performing successful nerve root blocks. The techniques we describe come from our training and ongoing experience. There are other acceptable methods as well.

Efficacy of epidural injections of Kenalog and Celestone in the treatment of lower back pain

OBJECTIVE

Epidural corticosteroid injections have been used extensively to treat lower back pain, but the relative effectiveness of one corticosteroid versus another has never been reported in a large patient series. We retrospectively reviewed 597 patients who had epidural corticosteroid injections to determine any difference in Kenalog or Celestone efficacy.

MATERIALS AND METHODS

We reviewed charts and self-reported pain score evaluations of 597 patients who received either Kenalog or Celestone Soluspan as an epidural injection for the treatment of lower back pain from 1997 to 2002 at our university hospital and affiliated Veterans Affairs hospital. Kenalog was used for the initial 2 years and Celestone was used for the next 3 years. Fluoroscopic guidance was used to confirm epidural location, and each patient was injected with a mixture of 5 mL of 0.5% preservative-free lidocaine and 2 mL of either Kenalog 40 mg/mL (triamcinolone acetonide injectable suspension) or Celestone Soluspan 6 mg/mL (betamethasone sodium phosphate and betamethasone acetate injectable suspension). Each patient was given a standardized pain evaluation sheet that used an 11-point scale for initial pain severity. Scoring of pain compared with baseline during the following 14 days was based on a 5-point scale of pain improvement or worsening.

RESULTS

On days 0-3 after the procedure, no statistical significance in improvement of lower back and buttock pain was seen between groups. On day 7, 59% of Celestone recipients and 73% of Kenalog recipients showed improvement in lower back pain (p = 0.002, Pearson's chi-square test), and 58% of Celestone recipients and 75% of Kenalog recipients had improvement in leg or buttock pain (p < 0.001). On day 14, 54% of Celestone recipients and 71% of Kenalog recipients showed improvement in lower back pain (p < 0.001), and 54% of Celestone recipients and 71% of Kenalog recipients had improvement in leg or buttock pain (p < 0.001).

CONCLUSION

The epidural injection of Celestone Soluspan and Kenalog reduced lower back and radicular pain in more than half the patients, although Kenalog reduced pain in a significantly larger number of patients than Celestone Soluspan at 1 and 2 weeks after injection.

Sublabral foramen and buford complex: inferior extent of the unattached or absent labrum in 50 patients

PURPOSE

To determine the inferiormost extent of the anterosuperior labral variants on conventional transverse MR images.

MATERIALS AND METHODS

We reviewed transverse MR images in 50 consecutive patients with a sublabral foramen or Buford complex at arthroscopy. Images were randomly mixed with those of 58 patients with either a normal labrum (n = 20) or an anterior labral tear (n = 38) at arthroscopy. MR imaging was fat suppressed fast spin echo intermediate or T2 weighted (repetition time msec/effective echo time msec, 1,800-3,000/30-102). Two radiologists evaluated by means of consensus the anterior labrum while blinded to patient history and arthroscopic results. Transverse images obtained through the glenoid fossa were totalled to determine the midpoint. Sensitivity, specificity, and accuracy of MR for depicting a sublabral foramen or Buford complex were calculated along with 95% CIs, by using surgical findings as the reference standard.

RESULTS

The sensitivity of MR for diagnosing a sublabral foramen or Buford complex was 0.94 (47 of 50 patients, 95% CI: 0.87, 1.00), specificity was 0.80 (16 of 20 patients, 95% CI: 0.62, 0.97), and accuracy was 0.90 (63 of 70 patients, 95% CI: 0.82, 0.97). The anterior labrum was abnormal on the first transverse section inferior to the midpoint in nine (18%) patients. The labrum was also abnormal on the second section below the midpoint in three (6%) patients. Because of the anterior tilt of the scapula, the midpoint was near the anterior glenoid notch at about the position between 2- and 3-o'clock.

CONCLUSION

The labrum may be unattached or absent on the first two transverse images obtained below the midpoint.

Usefulness of two indirect MR imaging signs to diagnose lateral meniscal tears

OBJECTIVE

We determined whether using two recently described indirect MR imaging signs would improve the sensitivity of diagnosis of lateral meniscal tears.

MATERIALS AND METHODS

We identified 121 consecutive patients who had undergone knee MR imaging and knee arthroscopy. Their MR imaging examinations were evaluated for the conventional criteria of a meniscal tear (meniscal distortion or intrameniscal signal contacting the surface) and the two new signs (presence of an abnormal popliteomeniscal fascicle and posterolateral pericapsular edema). These observations were correlated with the arthroscopic findings, which were used as the gold standard.

RESULTS

Thirty-two (89%) of the 36 torn lateral menisci had two or more images with distortion or signal contacting the surface. Three torn menisci and eight intact menisci had one image with distortion or surface signal. Only one of 75 menisci without distortion or surface signal was torn. An abnormal superior fascicle was highly associated (p < 0.001) with lateral meniscal tears but was not specific for a tear because three of the 14 menisci with abnormal fascicles were not torn. Posterolateral pericapsular edema was not associated with a lateral meniscal tear (p = 0.06). Using an abnormal fascicle as an additional criterion improved the sensitivity from 89% to 94%, but the difference was not statistically significant.

CONCLUSION

We confirmed that an abnormal fascicle is highly associated with a lateral meniscal tear but found that posterolateral pericapsular edema was not associated with lateral meniscal tears. Identifying an abnormal fascicle did not significantly improve the sensitivity of diagnosis of a lateral meniscal tear.

Chest radiology case exchange program: a paradigm for resident teaching and independent resident learning

RATIONALE AND OBJECTIVES

The purpose of this study was to test the effectiveness of resident-prepared, independent learning cases in teaching residents chest radiology.

MATERIALS AND METHODS

Three 2nd-year residents (one each from the University of Wisconsin, the Oregon Health Sciences University, and the University of Michigan) prepared four chest radiology teaching cases each (total, 12 cases). Radiology residents from each institution were randomly divided into control (n = 30) and experimental (n = 35) groups. Residents from both groups took a pretest of 36 multiple-choice questions covering the material from the 12 teaching cases. Residents in the experimental group reviewed these cases independently, and both groups took the same test (posttest) immediately after the teaching cases had been reviewed and again 3 months later (final test).

RESULTS

Test scores were similar across institutions (P > .05) but differed across time and treatment groups (experimental vs control) (P < .0001). Mean differences in test scores between the experimental and control groups at pretest, posttest, and final test were -0.4, +9.0, +4.0, respectively, demonstrating increased performance at posttesting that was still present (though somewhat attenuated) 3 months later at final testing.

CONCLUSION

Independent study of resident-prepared chest radiology teaching cases increases the resident's knowledge for as long as 3 months after instruction.