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MR imaging appearances of different types of reconstructive muscle flaps following reconstructive surgery of the lower extremity with associated post-surgical changes due to altered anatomy, radiation, and potential complications, can be challenging. A multidisciplinary therapeutic approach to tumors allows for limb salvage therapy in a majority of the patients. Decision-making for specific types of soft tissue reconstruction is based on the body region affected, as well as the size and complexity of the defect. Hematomas and infections are early complications that can jeopardize flap viability. The local recurrence of a tumor within six months after a complete resection with confirmed tumor-free margins and adjuvant radiation therapy is rare. Identification of a new lesion similar to the initial tumor favors a finding of tumor recurrence.

The purpose of this study was to establish normative data for the CT appearance of inguinal lymph nodes. After Institutional Review Board approval, search of the radiology information system identified 500 consecutive CT examinations of the pelvis. Patients were included if no lower extremity or perineum pathology, or history of malignancy at the time of CT examination, and a clinical note documenting no tumor at least 2 years after the CT. The final study group was 77 patients. CT examinations were retrospectively reviewed and bilateral inguinal lymph nodes were characterized by size (short axis and largest size in general), number, and presence of fat attenuation. The mean short-axis inguinal lymph node size was 5.4 mm (range 2.1–13.6 mm), measured at 8.8 mm two standard deviations above the mean. The mean number of superficial and deep inguinal lymph nodes was 10.7 (range 3–18) and 1.2 per patient (range 1–2), respectively. Superficial and deep inguinal nodes showed internal fat attenuation in 85 and 78 % of nodes, and were oval in shape in 95 and 78 %, respectively. Inguinal lymph nodes in asymptomatic patients have a mean short axis of 5.4 mm, a short axis of 8.8 mm at two standard deviations above the mean, and are multiple and symmetric in size and number (4–20 per patient). Normal inguinal lymph nodes were commonly oval in shape and contained fat, although such findings may be absent in smaller lymph nodes.

Objectives The purpose of this study was to determine whether any sonographic features of jumper's knee can predict the outcome after sonographically guided percutaneous patellar tendon fenestration. Methods Patients were identified between July 2001 and March 2009 who had clinical and sonographic findings of jumper's knee, who had failed conservative treatment, and who had sonographically guided percutaneous fenestration of the patellar tendon. Pain levels were assessed before and 4 weeks after fenestration. Sonograms were retrospectively characterized with regard to echogenicity, size, definition, location, calcification, and hyperemia of the abnormal patellar tendon region. Sonographic findings before fenestration were correlated with clinical outcomes. Results A total of 45 patellar tendons (32 consecutive patients) were included in the study. The average prefenestration functional pain score was 3.6 (range, 2-5), and the average postprocedure functional pain score after 4 weeks was 1.4 (range, 0-5). The preprocedure sonographic finding that correlated with an improved clinical outcome after tendon fenestration was the presence of a well-defined tendon abnormality. No other sonographic findings were associated with the clinical outcome. After fenestration, 76% (34 of 45) showed clinical improvement; 24% (11 of 45) showed no change; and 0% (0 of 45) had worse symptoms at 4 weeks. Conclusions The presence of a well-defined area of tendinosis on sonography was associated with clinical improvement after percutaneous sonographically guided fenestration of the patellar tendon. All tendons either improved (76%) or showed no change (24%) in the functional pain score at 4 weeks after fenestration.

Objectives Implanted mesh for inguinal hernia repair is often difficult to visualize with gray scale sonography and may present without the knowledge of the sonographer. We sought to evaluate the utility of the twinkling artifact produced by inguinal mesh to assist in mesh identification. Methods Two reviewers evaluated focused sonographic examinations of 44 inguinal regions, 24 of which had implanted inguinal mesh. The sonographic examinations consisted of static gray scale and color Doppler images with both linear and curvilinear array transducers. The presence of the twinkling artifact and visibility of the mesh were graded on a 4-point visibility scale. Results Inguinal mesh was not easily identified on gray scale imaging using either the curvilinear array (P = .5) or linear array (P = .5) transducer. The mesh was definitely seen in 3 of 24 inguinal regions using the linear array transducer and 2 of 24 inguinal regions using the curvilinear array transducer. In 79% of inguinal regions with mesh, the twinkling artifact was produced with the curvilinear array transducer only. The artifact was not elicited when using the linear array transducer. With the use of the curvilinear array transducer and the presence of the twinkling artifact, there was a significant chance of correctly identifying the presence of mesh (P Conclusions Standard gray scale imaging alone is not reliable when identifying inguinal mesh. The twinkling artifact was present in 79% of inguinal regions with mesh when evaluated with a low-frequency curvilinear array transducer.

Summary Objective To elucidate the role of body mass index (BMI) and knee osteoarthritis (OAK) by evaluating measures of body composition including fat mass and skeletal muscle mass (SMM). Methods Data are from 541 women enrolled in the Michigan Bone Health Study, a longitudinal, population-based study. At visits in 1998 and 2002, radiographs were taken of both knees and were evaluated for the presence of OAK (≥2 on the Kellgren–Lawrence (K–L) scale). Joint space width (JSW) was measured with electronic calipers. Fat mass and SMM were determined using bioelectrical impedance analysis. Results In 2002, the prevalence of OAK was 11% in this population of women whose mean age was 47 years. Fat mass, lean mass, SMM, waist circumference and BMI were greater in women with OAK compared to those without OAK. In multiple variable analyses adjusted for age, fat mass and SMM explained OAK prevalence and increasing OAK severity better than models with BMI; further SMM explained more variation than did fat mass. SMM was positively associated with level of left and right medial JSW while there was no consistent association of JSW and BMI or fat mass. Conclusion Fat mass and SMM were associated with K–L OAK score and the amount of joint space, with more variation explained by SMM. SMM was highly associated with JSW. Therefore, though obesity, frequently characterized by BMI, is a frequently reported risk factor for OAK, this mis-attribution may mean that interventions that focus on weight loss as treatment for osteoarthritis should be aware that this may negatively impact muscle mass.

This article evaluates the utility of performing a focused musculoskeletal sonography examination on the basis of patients' presenting complaints.Six hundred two patients evaluated over 6 months were scanned using a routine protocol. At the completion of the routine examination, each patient was asked to indicate a focal point of discomfort and, if present, was rescanned over the area of discomfort. Patients were classified in one of five categories depending on whether there was a focal point of discomfort and the presence or absence of an underlying sonographic abnormality.Eighty-three percent of the 602 patients had a sonographically detectable abnormality, 2.2% of whom had an abnormality not detectable by routine protocol-based scanning. The more peripheral the body part, the more likely that abnormalities detected by sonography correlated with focal symptoms: 81% in the wrist and hand and 73% in the ankle and foot, compared with the more central body parts of 15% in the shoulder and 31% in the hip. Chi-square analysis showed a significant association between the body part scanned and a detectable abnormality (p0.0001).Although a focused examination of the distal extremities correlated with an abnormality in most cases, a protocol-based approach ensured identifying 97.4% of the symptomatic abnormalities. The addition of a focused examination to an examination by protocol further increased the identification of abnormalities.

We have noted apparent far lateral meniscal attachment of the meniscofemoral ligament (MFL) with an anterior cruciate ligament (ACL) tear. This study evaluates MFL attachment and association with posterior horn lateral meniscus (PHLM) tear. Nine months of knee arthroscopy reports were reviewed to classify the PHLM and ACL as torn or normal. After excluding those with prior knee surgery, MR images were reviewed by two radiologists to determine the number of images lateral to PCL, which showed the ligaments of Humphrey and Wrisberg visible as structures separate from the PHLM. Any patient with abnormal PHLM surface signal not continuous with the MFL was excluded. MRI findings were compared with arthroscopy using Student’s t test and Fisher’s exact test. Of the 54 participants, 5 had PHLM tears and 49 were normal. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. The ligament of Humphrey inserted on average 0.9 consecutive images lateral to the PCL without an PHLM tear and 4.7 with an PHLM tear; the ligament of Wrisberg inserted on average 3.0 consecutive images without an PHLM tear and 4.5 with an PHLM tear (slice thickness/gap = 3 mm/0.5 mm). There was a significant association between PHLM tear and number of images (p = 0.0028), and between ACL tear and this type of PHLM tear (p = 0.0064). Apparent far lateral meniscal extension of a meniscofemoral ligament (greater than or equal to four images lateral to the PCL) should be considered as a possible PHLM tear, especially in the setting of an ACL tear.

OBJECTIVE. We have found in our practice that the normal extensor retinaculum of the wrist may appear hypoechoic on sonography and, because it is closely applied to the extensor tendons, may simulate tenosynovitis. This study prospectively evaluates the extensor retinaculum in 50 healthy adult volunteers, characterizing its sonographic appearance.CONCLUSION. The extensor retinaculum has a characteristic appearance on sonography. A hypoechoic appearance from anisotropy should not be confused with tenosynovitis.

OBJECTIVE. Accurate characterization of acetabular fractures can be difficult because of the complex acetabular anatomy and the many fracture patterns. In this article, the five most common acetabular fractures are reviewed: both-column, T-shaped, transverse, transverse with posterior wall, and isolated posterior wall. Fracture patterns on radiography are correlated with CT, including multiplanar reconstruction and 3D surface rendering.CONCLUSION. In the evaluation of the five most common acetabular fractures, assessment of the obturator ring, followed by the iliopectineal and ilioischial lines and iliac wing, for fracture allows accurate classification. CT is helpful in understanding the various fracture patterns.

OBJECTIVE. The purpose of this article is to describe the anatomy of the inguinal region in a way that is useful for sonographic diagnosis of inguinal region hernias, and to illustrate the sonographic appearance of this anatomy. We show sonographic techniques for evaluating inguinal, femoral, and spigelian hernias and include surgically proven examples.CONCLUSION. Understanding healthy inguinal anatomy is essential for diagnosing inguinal region hernias. Sonography can diagnose and differentiate between various inguinal region hernias.

To prospectively compare magnetic resonance (MR) imaging-defined abnormalities of osteoarthritis (OA) of the knee with radiographic severity measurements of OA of the knee and self-reported pain.This study was approved by the institutional review board of University of Michigan. Informed consent was obtained for this HIPAA-compliant study. Knee MR imaging was performed in 117 women (mean age, 46 years; range, 32-56 years) from a community-based arthritis study (n = 1053) with 30 women in each of four categories: (a) no pain and no OA of the knee, (b) no pain and OA of the knee, (c) pain and no OA of the knee, and (d) pain and OA of the knee. OA of the knee was defined from radiographs. Two hundred thirty-two eligible knees had Kellgren-Lawrence scores for OA of the knee as follows: grade 0, 115 (49.6%); grade 1, 33 (14.2%); grade 2, 66 (28.4%); grade 3, 17 (7.3%); and grade 4, one (0.4%). MR images were assessed for location and severity of defects of cartilage, bone marrow edema (BME), osteophytes, subchondral cysts, sclerosis, meniscal and/or ligamentous tears, joint effusion, synovial cysts, and synovitis. MR imaging findings were compared with radiographic severity of OA of the knee (Kellgren-Lawrence scale) and self-reported pain with analysis of variance, t tests, and contingency table analyses.Defects of cartilage (higher than grade IIA) were found in 75% of knees; BME was found in 57% of knees (1 cm, 41%;1 cm, 16%). Large BME lesions were common in the pain and OA of the knee group (P = .001); this group was significantly more likely to have defects of cartilage (P = .001); meniscal tears (P = .001); and osteophytes, subchondral cysts, sclerosis, joint effusion, and synovitis (P.001). Defects of cartilage, osteophytes, sclerosis, meniscal or ligamentous tears, joint effusion, and synovitis were strongly related to increasing Kellgren-Lawrence grade (P.001).In middle-aged women, there were significant associations between pain, radiographic severity of OA of the knee, and seven MR imaging-identified parameters.

Six patients were retrospectively identified as having undergone lateral ligament reconstruction surgery. The surgical procedures were categorized into four groups: direct lateral ligament repair, peroneus brevis tendon rerouting, peroneus brevis tendon loop, and peroneus brevis tendon split and rerouting. At radiography and magnetic resonance (MR) imaging, the presence of one or more suture anchors in the region of the anterior talofibular ligament indicates direct ligament repair, whereas a fibular tunnel indicates peroneus brevis tendon rerouting or loop. Both ultrasonography (US) and MR imaging demonstrate rerouted tendons as part of lateral ankle reconstruction; however, MR imaging can also depict the rerouted tendon within an osseous tunnel if present, especially if T1-weighted sequences are used. Artifact from suture material may obscure the tendon at MR imaging but not at US. With both modalities, the integrity of the rerouted peroneus brevis tendon is best evaluated by following the tendon proximally from its distal attachment site, which typically remains unchanged. The rerouted tendon or portion of the tendon can then be traced proximally to its reattachment site. Familiarity with the surgical procedures most commonly used for lateral ankle ligament reconstruction, and with the imaging features of these procedures, is essential for avoiding diagnostic pitfalls and ensuring accurate assessment of the ligament reconstruction.

Obese individuals have slowed conduction in the median nerve across the wrist, but the mechanism for this is not established. This case-control study of 27 obese subjects and 16 thin subjects was designed to test the hypothesis that obese individuals have higher carpal canal pressures and more median nerve swelling than thin individuals. All subjects were asymptomatic for hand symptoms, and had measurements of median and ulnar sensory nerve conduction in the nondominant hand, ultrasound measurement of the median nerve cross-sectional area proximal to the carpal canal, and carpal canal pressure measurement. There was no difference in age or gender ratio between the obese and thin groups. The median nerve cross-sectional area was equal in the obese and thin groups (9.3 mm2 vs. 9.4 mm2), as was the carpal canal pressure (16.2 mmHg vs. 15.5 mmHg, respectively). There was a strong correlation between median nerve conduction slowing across the wrist and median nerve cross-sectional area at the wrist (r = 0.55, P = 0.002). Obesity does not influence carpal canal pressure or the size of the median nerve at the wrist. However, there is a strong association between slowed median nerve conduction and increased nerve size which suggests endoneurial edema as a metabolic mechanism; the conduction slowing does not appear to be related to mechanical stress. Muscle Nerve 30: 481–485 2004

Objective With the use of surgical findings as the reference standard, the purpose of this study was to describe the sonographic findings of partial-thickness and complete tears of the quadriceps tendon and to determine whether sonography can potentially aid diagnosis. Methods Three hundred eighty-nine consecutive sonographic reports (January 1996 to April 2001) of the knee/quadriceps tendon were reviewed retrospectively and assessed for subsequent surgery on the quadriceps tendon. Seven cases were thus identified. Findings at surgery (complete versus partial tears) were compared with the original sonography reports. Results All 4 partial tears and 1 of 2 complete tears were diagnosed correctly on the basis of sonography. One complete tear was described as a partial tear on the basis of sonography. In a seventh case, complete disruption of the extensor mechanism with osseous avulsion of the superior pole of the patella was identified correctly. Dynamic scanning was essential in diagnosing a partial quadriceps tendon tear in 1 case. Conclusions Sonography, including the use of dynamic evaluation, was helpful in the diagnosis of partial-thickness tears of the quadriceps tendon and may aid in differentiation of such cases from complete quadriceps tendon tears, particularly in the acute setting. The presence of scar tissue in the setting of chronic injury may represent a potential pit-fall in the assessment of partial versus complete quadriceps tears. Further study is needed to define the accuracy of sonography for detecting quadriceps tendon tears.

OBJECTIVES The purpose of this article is to evaluate the diagnostic accuracy of sonography in clinically occult femoral hernias and to describe our sonographic technique. METHODS The clinical and imaging data for 93 outpatients referred by general surgeons, all of whom underwent sonographic evaluation and surgery, were reviewed retrospectively. Of these, 55 patients who underwent surgical exploration for groin hernias within 3 months of sonography and met all inclusion criteria were included in the study. The sonographic technique involves using the pubic tubercle as an osseous landmark to identify and appropriately visualize the femoral canal. The Valsalva maneuver is then used to differentiate the movement of normal fat (a potential pitfall) from true herniation in the femoral canal. Surgical findings were used as the reference standard by which sonographic results were judged. Two-by-two contingency tables were used to calculate the sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS In these 55 patients, surgery revealed 15 femoral hernias. Eight femoral hernias occurred in women, and 7 occurred in men. For diagnosing femoral hernias, sonography demonstrated sensitivity of 80%, specificity of 88%, a positive predictive value of 71%, and a negative predictive value of 92%. True-positive cases of femoral hernias have a sonographic appearance of a hypoechoic sac with speckled internal echoes. When examining during the Valsalva maneuver, a femoral hernia passes deep to the inguinal ligament, expands the femoral canal, displacing the normal canal fat, and effaces the femoral vein. CONCLUSIONS Sonography can exclude femoral hernias with high confidence in light of its exceptional negative predictive value. With attention to technique and imaging criteria, the diagnostic accuracy of sonography can be enhanced.

The objective of our study was to sonographically characterize the dorsal aspect of the scapholunate ligament in cadaveric wrists using arthrography, MR arthrography, and anatomic correlation as the gold standard.The dorsal aspect of the scapholunate ligament in four cadaveric wrists was evaluated on sonography without knowledge of the findings from standard arthrography, MR arthrography, and anatomic sectioning. The sonographic findings were compared with the findings from other modalities. The criteria for an abnormal scapholunate ligament included an abnormal contrast communication between the radiocarpal and midcarpal joints on arthrography and a discontinuity of the dorsal aspect of the scapholunate ligament that was documented both on MR arthrography and at anatomic sectioning.Arthrography, MR arthrography, and anatomic sectioning showed the dorsal aspect of the scapholunate ligament to be normal in one specimen and abnormal in three specimens. On sonography, the normal scapholunate ligament was hyperechoic between the scaphoid and lunate bones. In the three cases of abnormality, a normal scapholunate ligament was not visualized, and an abnormal hypoechogenicity was present.The dorsal aspect of the scapholunate ligament can be depicted on sonography; abnormality is present in patients in whom the normally hyperechoic fibrillar ligament is hypoechoic or absent.

Osteoarthritis (OA) has been characterized as a slowly evolving degenerative disease affecting cartilage and bone, with a multifactorial etiology that may differ depending on the joint site. Because OA has been considered a disease of the elderly, few population-based studies have examined its frequency and characteristics in persons under the age of 45. Objective In this cross-sectional study, we examined X-rays of both knees and the dominant hand in a population of younger black and white pre- and perimenopausal women in southeastern Michigan ( N =1053) for evidence of osteoarthritis, and reported these outcomes according to the risk factors of age, body size, injury, and smoking behavior. Design Sixteen joints of the dominant hand as well as both knee joints (weight bearing) were evaluated using the Kellgren and Lawrence Atlas of Standard Radiographs of Arthritis. Results By age 40, radiographically-defined osteoarthritis emerges in both the hands and knees. These age characteristics are observed in both black and white women, however prevalence of knee OA was higher in black females (23.1%) compared with white females (8.5%), and although prevalence of hand OA was more comparable between black (25.5%) and white females (19.2%), the joint sites affected differed. The major risk factors reported in studies of older populations are present in this younger population where OA is newly emerging. Conclusions This study provides strong evidence that primary prevention of OA must be implemented in young adulthood to curtail the emergence of radiographically-defined OA at the mid-life.

Ventilation/perfusion scans with single-photon emission tomography (SPET) were reviewed to determine their usefulness in the evaluation of lung volume reduction surgery (LVRS) candidates, and as a predictor of outcome after surgery. Fifty consecutive planar ventilation (99mTc-DTPA aerosol) and perfusion (99mTc-MAA) scans with perfusion SPET of patients evaluated for LVRS were retrospectively reviewed. Technical quality and the severity and extent of radiotracer defects in the upper and lower halves of the lungs were scored from visual inspection of planar scans and SPET data separately. An emphysema index (EI) (extent x severity) for the upper and lower halves of the lung, and an EI ratio for upper to lower lung were calculated for both planar and SPET scans. The ratios were compared with post-LVRS outcomes, 3, 6 and 12 months after surgery. All perfusion and SPET images were technically adequate. Forty-six percent of ventilation scans were not technically adequate due to central airway tracer deposition. Severity, extent, EI scores and EI ratios between perfusion and SPET were in good agreement (r = 0.52-0.68). The mean perfusion EI ratio was significantly different between the 30 patients undergoing biapical LVRS and the 17 patients excluded from LVRS (3.3+/-1.8 versus 1.2+/-0.7; P0.0001), in keeping with the anatomic distribution of emphysema by which patients were selected for surgery by computed tomography (CT). The perfusion EI ratio correlated moderately with the change in FEV1 at 3 months (r = 0.37, P = 0.04), 6 months (r = 0.36, P = 0.05), and 12 months (r = 0.42, P = 0.03), and the transition dyspnea index at 6 months (r = 0.48, P = 0.014) after LVRS. It is concluded that patients selected to undergo LVRS have more severe and extensive apical perfusion deficits than patients not selected for LVRS, based on CT determination. SPET after aerosol V/Q imaging does not add significantly to planar perfusion scans. Aerosol DTPA ventilation scans are not consistently useful. Perfusion lung scanning may be useful in selecting patients with successful outcomes after LVRS.

The purpose of our study was to determine if three-level thin-section CT depicts idiopathic pulmonary fibrosis (IPF) pathology as accurately as CT obtained at 10-mm increments throughout the entire lungs.Thin-section (1.0- to 1.5-mm) images at 10-mm increments were obtained and scored prospectively in 25 consecutive patients with newly diagnosed IPF who were participating in a Special Center of Research grant for interstitial lung disease. Each patient's lobe was scored by four thoracic radiologists on a scale of 0-5 for both ground-glass attenuation and fibrosis. The radiologists used three images (limited CT) and also used the entire data set (complete CT). CT scores were compared with pathology scores from 67 open and thoracoscopic biopsies. Limited and complete scores were compared with each other (Pearson correlation coefficient). Interobserver variation in the CT scoring system was assessed using kappa values.CT fibrosis scores strongly correlated with pathology fibrosis scores for complete (r = .53, p = .0001) and limited (r = .50, p = .0001) CT. CT ground-glass scores correlated with the histologic inflammatory scores for each lobe on complete (r = .27, p = .03) and limited (r = .26, p = .03) CT. The desquamative subcomponent of the pathology inflammatory score had the highest correlation with the CT ground-glass scores (complete: r = .29, p = .01; limited: r = .33, p = .007). Good interobserver agreement existed for both the alveolar and fibrosis components of the CT scoring system (kappa values ranging from .51 to .83) for each lobe of the lung on limited and complete CT.Limited thin-section CT reveals the pathologic changes associated with IPF as well as CT obtained at 10-mm increments. An added advantage of limited thin-section CT is that it exposes patients to less radiation.

We undertook this study to determine the CT findings of lipomatous hypertrophy of the interatrial septum, an asymptomatic and underrecognized benign proliferation of fat within the atrial septum.We retrospectively identified 12 cases of lipomatous hypertrophy of the interatrial septum by searching the radiology records at our institution from 1991 to 1995. We reviewed the CT scans of these patients to determine the distribution and morphology of fat within the interatrial septum.In all patients with lipomatous hypertrophy, a mass of fat attenuation extended from the coronary sinus to just above the level of the aortic root with relative sparing of the fossa ovalis, which resulted in a dumbbell configuration. Average dimensions were 7 cm for craniocaudal extent (range, 6-9 cm), 4.5 cm along the interatrial septum (range, 3.6-6.2 cm), and 2.7 cm perpendicular to the septum (range, 1.5-4.8 cm). Increased epicardial fat was seen on CT scans in 10 patients (83%). CT revealed mediastinal lipomatosis in six patients (50%). No patients had undergone corticosteroid treatment or total parenteral nutrition. No electrocardiographic or functional cardiac abnormalities were seen.On standard, high-resolution, and enhanced CT images, lipomatous hypertrophy of the interatrial septum is shown as a nonenhancing smoothly marginated homogeneous dumbbell-shaped mass of fat attenuation confined to the interatrial septum. These characteristic morphologic features allow confident diagnosis and help differentiate this benign condition from other cardiac masses.

OBJECTIVE The objective of this study was to describe the morphology of the rotator cuff tendon tears and long-term shoulder disability in conservatively treated elderly patients and determine if an association exists between these factors. METHODS Assessment of the rotator cuff tendon tear dimensions and depth, rotator interval involvement, rotator cable morphology and location, and rotator cuff muscle status was carried out on magnetic resonance studies of 24 elderly patients treated nonoperatively for rotator cuff tendon tears. Long-term shoulder function was measured using the Western Ontario Rotator Cuff (WORC) index; Disabilities of the Shoulder, Arm, and Hand questionnaire; and the American Shoulder Elbow Self-assessment form, and a correlation between the outcome scores and morphologic magnetic resonance findings was carried out. RESULTS The majority of large rotator cuff tendon tears are limited to the rotator cuff crescent. Medial rotator interval involvement (isolated or in association with lateral rotator interval involvement) was significantly associated with WORC physical symptoms total (P = 0.01), WORC lifestyle total (P = 0.04), percentage of all WORC domains (P = 0.03), and American Shoulder Elbow Self-assessment total (P = 0.01), with medial rotator interval involvement associated with an inferior outcome. CONCLUSIONS Medial rotator interval tears are associated with long-term inferior outcome scores in conservatively treated elderly patients with large rotator cuff tendon tears.

To describe the radiographic appearance of extracorporeal membrane oxygenation (ECMO) in adults and to correlate lung opacity with physiologic parameters and mortality.Chest radiographs of 50 adults treated with ECMO were reviewed; pre-ECMO radiographs were available in 35 patients. Lung opacity was assigned a score of 0-4. Complications of ECMO seen at chest radiography were recorded.The lung opacity scores of the first post-ECMO radiographs were higher than those of the pre-ECMO radiographs in 17 of 35 patients (P = .0005). Maximum opacity score was significantly lower for patients who survived compared with those who died (P = .001). Twelve of 14 patients (86%) with a maximum opacity score of 4 died, compared with eight of 29 patients (28%) with a maximum score of 3. Sixteen of 26 patients (61%) with evidence of baro-trauma died, compared with six of 24 patients (25%) without pneumothorax (P = .02). Four patients developed hemothorax.Lung opacity increases immediately after initiation of ECMO. Increased opacity corresponds to decreased pulmonary function, and severe opacity correlates strongly with mortality.

The osseous pelvis is a well-recognized site of origin of numerous primary and secondary musculoskeletal tumors. The radiologic evaluation of a pelvic lesion often begins with the plain film and proceeds to computed tomography (CT), or magnetic resonance imaging (MRI) and possibly biopsy. Each of these modalities, with inherent advantages and disadvantages, has a role in the workup of pelvic osseous masses. Clinical history and imaging characteristics can significantly narrow the broad differential diagnosis for osseous pelvic lesions. The purpose of this review is to familiarize the radiologist with the presentation and appearance of some of the common benign neoplasms of the osseous pelvis and share our experience and approach in diagnosing these lesions.

The objective of our study was to assess the prevalence, morphology, and position of the rotator cable and the relation of this structure to the rotator cuff crescent.Ultrasound examinations of bilateral shoulders of asymptomatic volunteers and of the asymptomatic shoulder in patients referred for assessment of a symptomatic contralateral shoulder were performed. The images were assessed by two radiologists for the presence of the rotator cable and measurements were performed.The rotator cable was identified in 99% of 108 asymptomatic shoulders (49 men, 59 women) (mean age, 45 years; range, 21-79 years). The mean thickness and the mean width of the rotator cable were 1.86 mm (range, 0.6-3.5 mm) and 11.5 mm (range, 7.6-17.7 mm), respectively. The mean distance between the lateral edge of the rotator cable and the medial aspect of the greater tuberosity was 8.9 mm (range, 3.6-15.4 mm). The mean rotator cuff crescent thickness was 3.7 mm (range, 2.5-5.3 mm). A statistically significant positive correlation was found between the thickness of the rotator cable and the thickness of the rotator cuff (p0.0001) and between the thickness of the rotator cuff and patient age (p=0.029).The rotator cable is a consistent structure seen in 99% of shoulders in this study. The morphology of this structure is variable, but rotator cable thickness correlated positively with the thickness of the rotator crescent.

The purpose of this study was to examine the range and prevalence of asymp tomatic findings at sonography of the shoulder.The study sample comprised 51 consecutively enrolled subjects who had no symptoms in either shoulder. Ultrasound of one shoulder per patient was performed by a musculoskeletal sonographer according to a defined protocol that included imaging of the rotator cuff, tendon of the long head of the biceps brachii muscle, subacromial-subdeltoid bursa, acromioclavicular joint, and posterior labrum. The shoulder imaged was determined at random. The 51 scans were retrospectively analyzed by three fellowship-trained musculoskeletal radiologists in consensus, and pathologic findings were recorded. Subtle or questionable findings of mild tendinosis, bursal prominence, and mild osteoarthritis were not recorded.Twenty-five right and 26 left shoulders were imaged. The subject age range was 40-70 years. Ultrasound showed subacromial-subdeltoid bursal thickening in 78% (40/51) of the subjects, acromioclavicular joint osteoarthritis in 65% (33/51), supraspinatus tendinosis in 39% (20/51), subscapularis tendinosis in 25% (13/51), partial-thickness tear of the bursal side of the supraspinatus tendon in 22% (11/51), and posterior glenoid labral abnormality in 14% (7/51). All other findings had a prevalence of 10% or less.Asymptomatic shoulder abnormalities were found in 96% of the subjects. The most common were subacromial-subdeltoid bursal thickening, acromioclavicular joint osteoarthritis, and supraspinatus tendinosis. Ultrasound findings should be interpreted closely with clinical findings to determine the cause of symptoms.

Objective. In our clinical practice, we have noted a caliber change of the posterior interosseous nerve (PIN) at the elbow as seen in the long axis on sonography simulating nerve entrapment. The objective of this study was to characterize the PIN using sonography in asymptomatic individuals. Methods. Our study retrospectively characterized the PIN in 50 elbows of 47 asymptomatic patients with sonography. Measurements of the PIN in a short-axis cross section using the circumferential trace technique and the anteroposterior (AP) dimension in the long axis were made proximal, at, and distal to the arcade of Frohse. Results. There was reduction of the AP dimension of the PIN distal to the arcade of Frohse when compared with the measurements at the arcade of Frohse and proximal to the arcade (P < .0001); however, there was no significant difference between the cross-sectional area of the PIN at all 3 levels (P = .59). Condusions. The PIN normally flattens as it enters into the supinator muscle without a notable chanqe in the cross-sectional area. This appearance should not be misinterpreted as nerve entrapment when imaged in the long axis.

Objective The purpose of this presentation is to review pathologic conditions that lead to pain at the radial aspect of the distal radius and to address anatomic variations of the first extensor compartment that exist and may have diagnostic and therapeutic implications. Methods Our presentation is based on a review of cases from teaching files and observations made in anatomic specimens. Results The discussed conditions include de Quervain tenosynovitis, intersection syndrome, and Wartenberg syndrome. Sonographic diagnosis of these conditions is addressed, and correlations are provided with anatomic specimens. Conclusions Sonography is able to depict and differentiate between these conditions.

The purpose of our study was to determine which wrist fractures are not prospectively diagnosed at radiography using CT as a gold standard and to identify specific fracture patterns.Through a search of radiology records from January 1 to December 31, 2005, 103 consecutive patients were identified as having radiographic and CT examinations of the wrist. After excluding incomplete or nondiagnostic examinations and those with a greater than 6-week interval between imaging studies, the final study group consisted of 61 wrist examinations in 60 patients. Two musculoskeletal radiologists and one emergency radiologist blindly reviewed CT examinations, and each bone (scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate, metacarpals, distal radius, distal ulna) was categorized as normal or fractured, with agreement reached by consensus. Each prospective radiographic report was categorized as either normal or fracture/equivocal for each osseous structure. Results were compared using the chi-square and Fisher's exact tests.In the proximal carpal row, lunate and triquetrum fractures were often radiographically occult (0% and 20%, respectively, detected at radiography); whereas in the distal carpal row, trapezoid, capitate, and hamate fractures were often occult (0%, 0%, and 40% detected at radiography, respectively). Hamate fractures were significantly associated with metacarpal fractures, and distal radius fractures were associated with scaphoid and ulna fractures.Thirty percent of wrist fractures were not prospectively diagnosed on radiography, suggesting that CT should be considered after a negative radiographic finding if clinically warranted. The location of a dorsal scaphoid avulsion fracture emphasizes the need for specific radiographic views or cross-sectional imaging for diagnosis.

OBJECTIVE. The purpose of this article is to show the typical locations of anterior abdominal wall and inguinal region hernias and to illustrate their sonographic appearances and describe pitfalls in clinical diagnosis of hernias that may be resolved with sonography.CONCLUSION. Awareness of the expected locations of anterior abdominal wall hernias and potential clinical pitfalls allows an accurate diagnosis of a hernia and helps in differentiating a hernia from other abnormalities.

To characterize the ultrasonographic (US) appearance of the rotator cuff cable in asymptomatic shoulders and in cadaveric specimens, with histologic comparison for the latter.The cadaveric portion of this study was approved by the institution's Anatomical Donations Department. Institutional review board approval and informed consent were obtained from asymptomatic volunteers and clinical patients for the HIPAA-compliant portion of the study. Four fresh cadaveric shoulder specimens (two male subjects, 40 and 50 years old) were dissected, assessed for the presence of the rotator cable, and imaged with 12-MHz US. Histologic slides (hematoxylin-eosin stain) from three resected rotator cuff tendons were inspected for fibers in the expected location and orientation of the rotator cuff cable. The shoulders in 17 asymptomatic volunteers (seven men, two women; age range, 27-66 years; mean, 41 years) and contralateral asymptomatic shoulders in 10 patients (six men, four women; age range, 24-78 years; mean, 49 years) were scanned and evaluated for the presence and appearance of the rotator cable.The rotator cable was identified at gross dissection. Histologic examination and US of the cadaveric shoulders demonstrated an articular-sided fibrillar structure perpendicular to the rotator cuff tendon (average thickness and width, 1.2 mm and 4.5 mm, respectively). US of asymptomatic shoulders depicted a similar fibrillar structure in three (11%) shoulders up to 1.1-1.5 cm medial to the greater tuberosity (average thickness and width, 1.2 mm and 4.5 mm respectively).The rotator cable can be depicted with US.

To determine if levels of endogenous estrogen or estrogen metabolites are associated with an increased risk of developing knee osteoarthritis (OA) in women.Serum estradiol (E2) and 2 urinary estrogen metabolites (2-hydroxyestrone and 16alpha-hydroxyestrone) with radiographically defined prevalent and incident knee OA in 842 white and African American women from the Southeast Michigan Arthritis Cohort.The mean age and body mass index (BMI) of women in the cohort were 42.3 years and 28.5 kg/m2, respectively. Women who developed radiographically defined knee OA had significantly greater odds of having baseline endogenous early follicular phase estradiol concentrations in the lowest tertile (47 pg/ml; odds ratio [OR] 1.88, 95% confidence interval [95% CI] 1.07-3.51) compared with those with estradiol concentrations in the middle tertile [47-77 pg/ml]), after adjustment for age, BMI, and other covariates. Women who developed knee OA also had greater odds of having baseline urinary concentrations of 2-hydroxyestrone in the lowest tertile (OR 2.9, 95% CI 1.49-5.68) compared with women with 2-hydroxyestrone concentrations in the middle tertile), after adjustment for covariates. Women who developed knee OA were more likely to have a ratio of 16alpha-hydroxyestrone to 2-hydroxyestrone in the highest tertile (0.86; OR 1.86, 95% CI 1.01-3.44 compared with women with ratios in the 0.54-0.86 range), after adjustment for other covariates.There were significant associations of lower baseline serum estradiol and urinary 2-hydroxyestrone with developing knee OA in middle-aged women.

To retrospectively evaluate the imaging features of os peroneum fractures and associated peroneus longus tendon injuries at radiography and ultrasonography (US) and to retrospectively compare these imaging features with those of multipartite os peroneum.Institutional review board approval was obtained and informed consent was waived for this HIPAA-compliant study. Retrospective review of findings in nine patients (five men, four women; age range, 35-59 years) with os peroneum fracture at radiography and lateral foot pain after injury who had undergone US of the foot was performed. Three patients underwent magnetic resonance (MR) imaging, and two underwent surgery. Os peroneum fragment separation and displacement relative to the calcaneocuboid joint were measured on radiographs. Os peroneum fracture and peroneus longus tendon injuries were characterized with US and MR imaging. Review of 43 foot radiographs obtained in 36 control subjects (eight men, 28 women; age range, 18-84 years) who were found to have an os peroneum at radiography but were asymptomatic in that area was completed to measure os peroneum distance from the calcaneocuboid joint and bipartite os peroneum fragment distraction.Os peroneum fragment separation of 6 mm or more or displacement of the proximal fragment by 10 mm or more on a lateral radiograph or 20 mm or more on an oblique radiograph was associated with full-thickness peroneus longus tendon tear in seven of seven patients (100%). Os peroneum fragment separation of 2 mm or less or proximal displacement of 8 mm or less was associated with normal tendons, partial-thickness tears, or tendinosis. In the control subjects, os peroneum location ranged from 7 mm proximal to 8 mm distal to the calcaneocuboid joint on lateral radiographs and from 9 mm proximal to 8 mm distal to the joint on oblique radiographs. Bipartite os peroneum fragment separation was 2 mm or less.Os peroneum fragment separation of 6 mm or more suggests os peroneum fracture and associated full-thickness peroneus longus tendon tear. Separation of 2 mm or less may be seen with nondisplaced os peroneum fractures and bipartite os peroneum.

OBJECTIVE. We have found variability in the sonographic appearance of peripheral nerve sheath tumors. The purpose of this study was to characterize the sonographic appearances of pathologically proven peripheral nerve sheath tumors.CONCLUSION. Peripheral nerve sheath tumors are often hypoechoic with posterior acoustic enhancement and so may simulate a ganglion cyst. The presence of intrinsic blood flow on color Doppler sonography and peripheral nerve continuity suggests the diagnosis of peripheral nerve sheath tumor. Sonography cannot reliably distinguish neurofibromas from schwannomas.

To characterize the ultrasonographic (US) appearance of the anterior bundle of the ulnar collateral ligament of the elbow by comparing US images with magnetic resonance (MR) arthrograms and anatomic slices.The ulnar collateral ligament in four cadavers (eight elbows) was blindly evaluated with US by one musculoskeletal radiologist with experience in musculoskeletal US. These results were compared with standard arthrograms, MR arthrograms, and anatomic slices by consensus reading of two musculoskeletal radiologists. The criteria for an abnormal ulnar collateral ligament included contrast material extension into the ligament or fiber discontinuity, as documented by MR arthrography and anatomic slices.Standard arthrography, MR arthrography, and anatomic slices demonstrated the ulnar collateral ligament to be unequivocally normal in three specimens and abnormal in two. The remaining three elbows did not meet the criteria for classification as either normal or abnormal, and thus they were excluded from the study. With US, the normal ulnar collateral ligament was fibrillar and hyperechoic between the medial epicondyle and proximal ulna. In the two abnormal cases, abnormal hypoechogenicity and ligament fiber disruption were noted. In addition, the proximal aspect of the ulnar collateral ligament varied from a cordlike structure to a broad attachment to the undersurface of the medial epicondyle with variable fat.In this small sample, the anterior bundle of the ulnar collateral ligament is identified with US by its hyperechoic and compact fibrillar echotexture. The proximal attachment of the ulnar collateral ligament has a variable appearance. Hypoechogenicity and fiber disruption indicated ulnar collateral ligament abnormality.

One method for performing effective shoulder arthrography with a fluoroscopically guided anterior approach is described. The technique can ensure success while injury to the cartilaginous labrum is avoided, which is essential when arthrography is performed in conjunction with magnetic resonance (MR) imaging. The key features of the technique include supine positioning of the patient with the shoulder in external rotation, marking the skin just lateral to the humeral head cortex, inserting the needle perpendicular to the fluoroscopy beam, testing the injection with an anesthetic agent, and confirming intraarticular needle placement with iodinated contrast material. The procedure can be followed by an injection of dilute gadolinium solution for subsequent MR imaging. Proper patient and needle positioning as well as accurate confirmation of intraarticular needle placement are critical to a successful and atraumatic shoulder arthrographic examination. © RSNA, 2003

OBJECTIVE. This report describes sonography of ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware.CONCLUSION. Sonography can be helpful in identifying ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware. In such cases, dynamic sonography can aid assessment.

Our purpose was to determine if micronodular lung metastases from papillary thyroid cancer had diameters that were less than 1 mm and therefore of a size for which irradiation by radioiodine (131I) is inefficient. In five patients, lung metastases seen on computed tomography (CT) were enumerated and sized in the entire right lung and right upper lung giving volumes of measurable, ie, more than 1 mm diameter, tumors. Concentrations of diagnostic 131I were quantified scintigraphically in the same regions. Fractions of administered 131I per milliliter of tumor and the absorbed radiation from the subsequent treatments were calculated to see if the 131I levels in lungs were greater than expected for the visible tumor volumes. Two other patients manifesting similar findings had lung biopsies that were reviewed for size of metastases. The calculated fractions of administered activity per milliliter of tumor and the absorbed radiations from the treatments with 131I were exceptionally high. Biopsies revealed numerous tumors below the resolution of CT. We conclude that the fractions of administered activity and absorbed radiations of 131I in tumors were high because the measured tumor volumes underestimated the total tumor volumes. Many lung metastases were less than 1 mm in diameter.

Objective: We describe the CT appearance of pulmonary zygomycosis (mucormycosis), an opportunistic infection typically occurring in immunocompromised patients. Materials and Methods: Eight patients with pulmonary zygomycosis imaged with CT were reviewed, seven at initial diagnosis and one with a subsequent complication. The appearance, number, and location of pulmonary lesions and the presence of pleural effusions and extrapulmonary involvement were assessed. Rim enhancement, air bronchograms, the halo sign, air crescent sign, cavitation, and central low attenuation suggesting necrosis were recorded. Results: There were 14 nodules and 5 areas of mass-like or wedge-shaped consolidation. Pleural effusion was present in five patients, halo sign in three, central low attenuation in two, and cavitation in one. In the affected lobe 13 of 14 nodules and all consolidations were posterior. Of 19 lesions 16 (84%) were confined to the upper lobes, with 3 in the superior segment of a lower lobe. Endobronchial disease with lobar collapse was the only manifestation in one patient. Major complications were direct spinal invasion in one patient and multiple pulmonary artery pseudoaneurysms in another patient. Conclusion: In the appropriate clinical circumstance, nodules or mass-like or wedge-shaped consolidation, especially posteriorly in the upper lobes of the lung, should suggest zygomycosis. Endobronchial zygomycosis is less common.

Objective : To assess whether the presence of subchondral bone marrow abnormalities (bone marrow edema (BME)) and cartilage defects, determined by magnetic resonance imaging (MRI), would explain the difference between painful osteoarthritis of the knee (OAK) compared with painless OAK or pain without OAK. Method : Four groups of women (30 per group), aged 35–55 years, were recruited from the southeast Michigan Osteoarthritis cohort (group 1: painful OAK; group 2: painless OAK; group 3: knee pain without OAK; and group 4: no OAK or knee pain). OAK was defined by a Kellgren–Lawrence score of 2 or greater, while pain was based on self-report. BME and cartilage defects were identified from MRI. Results : BME lesions were identified in 56% of all knees. BME lesions were four times (95% CI=1.7, 8.7) more likely to occur in the painless OAK group as compared with the group with pain, but no OAK. BME lesions >1cm were more frequent (OR=5.0; 95% CI=1.4, 10.5) in the painful OAK group than all other groups. While the frequency of BME lesions was similar in the painless OAK and painful OAK groups, there were more lesions, >1cm, in the painful OAK group.About 75% of all knees had evidence of some cartilage defect, of which 35% were full-thickness defects. Full-thickness cartilage defects occurred frequently in painful OAK. One-third of knees with full-thickness defects and 47% of knees with cartilage defects involving bone had BME >1cm. Women with radiographic OA, full-thickness articular cartilage defects, and adjacent subchondral cortical bone defects were significantly more likely to have painful OAK than other groups (OR=3.2; 95% CI=1.3, 7.6). Conclusion : The finding on MRI of subchondral BME cannot satisfactorily explain the presence or absence of knee pain. However, women with BME and full-thickness articular cartilage defects accompanied by adjacent subchondral cortical bone defects were significantly more likely to have painful OAK than painless OAK.

Objective We assessed the probability that mid-aged women with a Kellgren and Lawrence (K–L) score of 1 are likely to progress to a score of 2 or regress to a score of zero at a second time point, 2–3 years later.Methods Osteoarthritis (OA) of measurements (weight-bearing X-rays and interviews) were undertaken in women from the Southeast Michigan population who were ≥40 years of age, and who participated in both the 1995 and 1998 measurements (N=679).Results Of the 17.1 % of women with a 1995 K–L score of 1 in their right knee, 37.1% had a K–L score of 1 in 1998 while 32.8 % had a score of ≥2 and 30.2% had a score of zero. For 26.0% of women, the score progressed by at least one unit over the 2.5 year period whereas scores for only 7.0% of women regressed in the same time period. Women who had a K–L score of 1 in the right knee in 1995 were 2.5 times more likely to have a K–L score of 1 in 1998 (95% CI=1.6–3.8); and were 2.2 times more likely to have a K–L score of 2 or greater (95% CI=1.4–3.5) in 1998 compared with other scores. These women were 74% less likely to have a score of zero in 1998 (95% CI=0.2–0.4). Further, other risk factors, specifically age and BMI were predictors of increasing K–L grade in 1998.Conclusion These findings suggest that a score of 1 is part of the advancement to emergent OAK; and suggest the following criteria to characterize individuals who are at an intervenable stage on the pathway toward OAK: age ≥40, BMI ≥30, and K–L score of ≥1. From the perspective of both the individual and the examiner, these assessment characteristics are relatively simple to assess clinically. Copyright 2002 OsteoArthritis Research Society Intenational. Published by Elsevier Science Ltd. All rights reserved.

Discrepancies exist between radiographic osteoarthritis of the knee (OAK) and report of knee joint pain. Little is known about how these two definitions of osteoarthritis (OA) and their correlates differ between African American (AA) and Caucasian (CA) women.Objective We compared the prevalence of radiographic OAK and knee joint pain in AA and CA women, and the congruency of these outcomes according to age, body size, and knee injury.Design A cross-sectional study of African American and Caucasian women aged 40–53 years (N=829) in Southeast Michigan used the Kellgren and Lawrence Atlas of Standard Radiographs of Arthritis to characterize radiographs of both knee joints (weight bearing) and self-report of knee pain.Results Current pain was a significantly more sensitive predictor of radiographic OAK among AA women (Se=0.51) compared to CA women (Se=0.35). Specificity was similar between AA women (Sp=0.77) and CA women (Sp=0.82). Positive predictive value was significantly greater for AA compared with CA women (PV+=0.40 and PV+=0.15, respectively). The odds of having radiographic OAK increased with BMI >32kg/m2in both groups. Knee pain was related to BMI in CA women, but not AA women. Previous knee injury was associated with knee pain in both AA and CA women (OR=3.0 and OR=2.4).Conclusions Joint pain in AA women was more likely to be associated with radiographic OAK as compared with CA women. This suggests differences in these two groups in both how pain is experienced in the OAK process and in the prevalence of non-OAK related pain in knee joints.

Objective We evaluated C-reactive protein (C-RP), a quantitative marker of the acute phase response, as a potential biomarker of prevalent and incident osteoarthritis of the knee (OAK). Methods Serum C-reactive protein concentrations were characterized with ultrasensitive rate nephelometry in a population-based sample of 1025 women (318 African-American and 707 Caucasian) who are enrollees in a study of musculoskeletal conditions at the mid-life. Assignment of OAK was based on Kellgren-Lawrence (K–L) scores of 2 or more on radiographs. Prevalent OAK was based on the baseline (1996) score while the classification of incident OAK was based on a score of 2 or greater at the follow-up examination 2.5 years later amongst those with a baseline K–L scores of 0 or 1. Results At baseline, the prevalence of radiographic OAK was 12% in participants who were aged 27–53 years and 18% in the subgroup of women aged 40–53 years. The mean C-RP value was 2.31mg/L, with values ranging from below detection (0.3mg/L) to 47.4mg/L. Higher C-RP concentrations were associated with both prevalent and incident OAK ( P 0.0001, and P 0.0001, respectively). For each K–L score increase from 0 to 3, there was a significantly higher mean C-RP value. Compared to women without incident OAK, women who developed OAK in the 2.5-year follow-up had significantly higher baseline C-RP concentrations. Women with bilateral OAK had higher C-RP concentrations than women with unilateral OAK (6.65mg/L±0.56 vs 3.63mg/L±0.42, P 0.007). BMI was highly correlated with C-RP ( r =0.58) and obesity was an effect modifier with respect to OAK and C-RP concentrations. When stratified according presence or absence of OAK and obesity (BMI >30kg/m 2 ), mean C-RP values were: obesity and OAK, 6.3±0.4mg/L; obesity but not OAK, 4.3mg/L±0.2; no obesity but OAK, 1.7mg/L±0.8; and neither obesity nor OAK, 1.3mg/L±0.2mg/L. These stratum means were significantly different from each other, indicating a higher C-RP with OAK after accounting for obesity. Conclusion C-RP, as a measure of an acute phase response and inflammation, is highly associated with OAK; however, its high correlation with obesity limits its utility as an exclusive marker for OAK. Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved .