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Objectives: The aim of this study was to compare the detection rate of and reader confidence in 0.55 T knee magnetic resonance imaging (MRI) findings with 3 T knee MRI in patients with acute trauma and knee pain., Materials and Methods: In this prospective study, 0.55 T and 3 T knee MRI of 25 symptomatic patients (11 women; median age, 38 years) with suspected internal derangement of the knee was obtained in 1 setting. On the 0.55 T system, a commercially available deep learning image reconstruction algorithm was used (Deep Resolve Gain and Deep Resolve Sharp; Siemens Healthineers), which was not available on the 3 T system. Two board-certified radiologists reviewed all images independently and graded image quality parameters, noted MRI findings and their respective reporting confidence level for the presence or absence, as well as graded the bone, cartilage, meniscus, ligament, and tendon lesions. Image quality and reader confidence levels were compared ( P < 0.05 = significant), and clinical findings were correlated between 0.55 T and 3 T MRI by calculation of the intraclass correlation coefficient (ICC)., Results: Image quality was rated higher at 3 T compared with 0.55 T studies (each P ≤ 0.017). Agreement between 0.55 T and 3 T MRI for the detection and grading of bone marrow edema and fractures, ligament and tendon lesions, high-grade meniscus and cartilage lesions, Baker cysts, and joint effusions was perfect for both readers. Overall identification and grading of cartilage and meniscal lesions showed good agreement between high- and low-field MRI (each ICC > 0.76), with lower agreement for low-grade cartilage (ICC = 0.77) and meniscus lesions (ICC = 0.49). There was no difference in readers' confidence levels for reporting lesions of bone, ligaments, tendons, Baker cysts, and joint effusions between 0.55 T and 3 T (each P > 0.157). Reader reporting confidence was higher for cartilage and meniscal lesions at 3 T (each P < 0.041)., Conclusions: New-generation 0.55 T knee MRI, with deep learning-aided image reconstruction, allows for reliable detection and grading of joint lesions in symptomatic patients, but it showed limited accuracy and reader confidence for low-grade cartilage and meniscal lesions in comparison with 3 T MRI., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Knee overload was detrimental to knee osteoarthritis subjects. We aim to analyze the association between the subchondral bone microarchitecture sclerosis and typical knee-straining activities., Methods: The frequency of experiencing squatting, kneeling, lifting, and climbing of 481 knee osteoarthritis subjects was investigated. Subchondral bone microarchitecture (bone volume fraction, trabecular thickness, trabecular separation, and trabecular number) was measured by the fast imaging with steady-state free precession magnetic resonance imaging applying trabecular sequencing, at baseline and 12-mo follow-up. Logistic regression was conducted to investigate the relationship between microarchitecture change and each knee-straining activity, adjusted by age, sex, weight, and Kellgren-Lawrence grade. All data were from the Osteoarthritis Initiative., Results: Long kneeling was associated with increased bone volume fraction (adjusted odds ratio = 1.16, confidence interval = 1.01-1.33) and trabecular number (adjusted odds ratio = 1.16, confidence interval = 1.02-1.33). Long squatting was associated with a lower risk of increased trabecular separation (adjusted odds ratio = 0.84, confidence interval = 0.71-0.98) and a higher risk of increased trabecular thickness (adjusted odds ratio = 1.29, confidence interval = 1.06-1.55). Long squatting also increased the medial compartment joint width narrowing (-0.21 in squatting group vs -0.03 in no squatting group, P < 0.05)., Conclusions: Knee osteoarthritis patients should avoid long squatting and kneeling, and subchondral bone microarchitecture possesses excellent potential as a monitoring indicator in subjects who kneel or squat for long., Competing Interests: Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

A 24-yr-old male soccer player presented with a 7-yr history of left posterior knee "looseness." Evaluation 7 yrs ago, at the time of initial injury, revealed atraumatic anterior and posterior cruciate ligament sprains. On representation, the patient described the pain as a constant, dull ache, 3/10, but his biggest complaint was this feeling of "instability" and looseness where his knee would "buckle" 3-4 times a week. Physical examination was positive for grade 1 posterior drawer and grade 1 posterior sag signs. Reverse KT-1000 testing showed a 3-mm side-to-side difference. Sonographic evaluation confirmed magnetic resonance imaging findings of posterior cruciate ligament laxity and buckling and a small cystic lesion abutting the posteromedial margin of the distal 1/3 of the posterior cruciate ligament. After a trial of physical therapy, the patient elected to undergo experimental injection of dextrose hyperosmolar solution. This resulted in resolution of the cyst and reverse KT-1000 measurements improved to a side-to-side difference of 1 mm. The patient's subjective feeling of looseness and instability resolved by 7 wks.

Characteristic injury patterns have been described in pedestrians struck by motor vehicles. The common injury pattern seen in upright pedestrians consists of a triad of head, pelvis, and lower extremity trauma. There are several factors such as vehicular type, design, mass and speed, and impact surfaces that influence the type and distribution of these injuries. We report a case that illustrates the importance of examination of the knee at autopsy when the typical lower extremity diaphyseal fractures that are usually seen in a motor vehicle-pedestrian collision are absent.

Introduction: Knee injuries are common in sports, and postinjury immobilization is often required to protect healing tissues and alleviate pain, but both the injury and the immobilization can lead to a knee contracture. Knee flexion contractures limit performance. Previous research has identified posterior knee capsule fibrosis as a contributor to immobility-induced knee flexion contractures. This study aims to measure posterior knee capsule length at various durations of remobilization after knee immobilization and to correlate with the recovery of knee range of motion., Methods: Two hundred fifty-nine male Sprague-Dawley rats had one knee extra-articularly immobilized in flexion with a Delrin® plate at a 45° angle for one of six durations: 1, 2, 4, 8, 16, or 32 wk, followed by spontaneous remobilization after plate removal, which lasted zero, one, two, and four times the duration of immobilization. The contralateral knees served as controls. The posterior knee capsule length was measured by histomorphometry. These measures were correlated with previously published range of motion data from the same cohort of specimens., Results: Knees immobilized for 1 and 2 wk partially recovered posterior capsule length (P > 0.05). Knees immobilized beyond 2 wk failed to recover posterior capsule length, irrespective of the duration of remobilization (P < 0.05). The residual posterior capsule shortening correlated with the lack of knee extension (P < 0.003)., Conclusions: For knee injuries requiring more than 2 wk of immobilization, unassisted remobilization will not restore posterior knee capsule shortening and the reduction in knee extension. These results support the role of the posterior capsule in knee joint contracture and the need to minimize the duration of immobility and to assist the recovery of the range of knee extension after a sport injury.

It is difficult to repair knee deep burn wounds in elderly patients. In this study, we observed the therapeutic effects of descending genicular artery-saphenous artery perforator flaps on knee deep burn wounds in elderly patients.Between December 2013 and February 2018, we repaired knee third-degree burn wounds using descending genicular artery-saphenous artery perforator flaps of 20 × 12 cm to 23 × 13 cm in 56 elderly patients. For the patella and patellar ligament with complete necrosis, the patella and patellar ligament were completely removed, whereas for the patella and patellar ligament with partial necrosis, necrotic parts were removed first. The donor area was repaired using intermediate thickness free skin graft. The 56 patients were 76- to 85 years' old and all had unilateral knee burn.All flaps survived in the 56 patients. After the follow-up of 2 to 36 months, the flaps were excellent in texture and appearance, and exhibited sensory recovery. In the 8 patients with completely necrotic patella and patellar ligament as well as open knee joint, the weight-bearing function of knee joint was retained, which met patients' requirements of limb salvage and weight-bearing function. In the other 48 patients with partially necrotic patella and patellar ligament as well as open joint capsule, the postoperative flexion and extension of the knee joint were good.In elderly patients, it is an effective method to repair knee deep burn wounds using the descending genicular artery-saphenous artery perforator flaps.

Purpose: We prospectively quantified the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of integrated parallel acquisition technique (PAT) and simultaneous multislice (SMS) acceleration and various combinations thereof, and we further compared two 4-fold-accelerated (PAT2-SMS2) high-resolution turbo spin echo (TSE) magnetic resonance imaging (MRI) protocols of the knee against a clinical 2-fold-accelerated (PAT2-SMS1) TSE standard., Materials and Methods: Institutional review board approval was obtained, and all subjects gave informed consent. Fourteen knee MRI examinations were obtained (8 men, 6 women; mean age, 46 years; age range, 28-62 years) using a 3 T MRI system and a TSE pulse sequence prototype that allowed for the combination of PAT and SMS acceleration. Predicted whole-body specific absorption rates were recorded for all pulse sequences. For quantitative analysis, the difference method was used to calculate SNR and CNR analysis of 6 different TSE acceleration schemes (PAT2-SMS1, PAT3-SMS1, PAT1-SMS2, PAT1-SMS3, PAT2-SMS2, and PAT2-SMS3). For qualitative analysis, sagittal intermediate-weighted and axial fat-suppressed T2-weighted MR images were obtained with PAT2-SMS1 and PAT2-SMS2 acceleration schemes using similar parameters. One faster PAT2-SMS2 acceleration scheme with decreased repetition time and longer echo train was labeled with the addition SPEED for the purpose of this report. Two readers rated the data sets for image quality, structural visibility, and overall observer satisfaction using equidistant 5-point Likert scales. Readers additionally noted the presence of cartilage defects, meniscal tears, tendons and ligament tears, and bone marrow edema pattern. Friedman and Kruskal-Wallis tests were used. P values of less than 0.01 were considered significant., Results: All pulse sequences were successfully executed and reconstructed inline. Whole-body specific absorption rates ranged between 1.4 and 3.9 W/kg for all acquisitions and remained within mandated limits. Quantitatively, mean SNR and CNR were significantly higher for SMS than those for PAT and similar for PAT2-SMS2 and PAT2-SMS1. Fluid was brightest on PAT2-SMS1, whereas noise, edge sharpness, contrast resolution, and fat suppression were similar on PAT2-SMS1 and SMS2-PAT2 and mildly inferior on PAT2-SMS2 SPEED. Articular cartilage received mildly higher ratings on PAT2-SMS1, whereas visibility of menisci was mildly inferior on PAT2-SMS2 SPEED. Observer preferences were similarly high for PAT2-SMS1 and PAT2-SMS2 and mildly inferior for the faster PAT2-SMS2 SPEED images. Four cartilage defects and 2 meniscal tears were seen by both readers on all sequences., Conclusions: We demonstrate the signal preservation capabilities of SMS over PAT acceleration, which allow for similar SNR and CNR of 4-fold PAT2-SMS2 and 2-fold PAT2-SMS1 acceleration. Four-fold-accelerated TSE through the combination of PAT2 and SMS2 enables approximately 50% shorter acquisition times compared with regular PAT2 acceleration, similar quantitative and qualitative image quality, and holds promise for a meaningful increase of the efficiency of clinical 2-dimensional MRI of the knee.

Sports injuries at the knee are very common, not only in contact sports such as football but also in sports with jumping and pivoting. In addition, overuse injuries can affect the tendons, ligaments, and bone with degeneration, friction, and stress response. Radiologists and sports medicine professionals should be familiar with the range of injury occurring at the knee and patterns of injury that can be used to predict other more subtle pathology. These topics and others will be discussed.

Objective: Patellotibial contusions are a recently described contusion pattern in anterior cruciate ligament (ACL) tears. The purposes or our study were to determine if patellotibial contusions are specific to ACL injuries, determine the internal derangements in patients demonstrating this contusion, and suggest a mechanism of injury., Materials and Methods: We conducted a retrospective search of radiology reports over a 6-year period to identify patients with patellar edema described on magnetic resonance (MR) imaging. Only individuals with patellar and tibial edema were included in the study group. These MR examinations were then reviewed for associated internal derangements., Results: From March 2007 to June 2013, 1914 MR examinations of the knee were performed. Two hundred seventy-one reports described patellar edema. Seven individuals had edema of both the inferior pole of the patella and the anterior tibial plateau. Three individuals were involved in motor vehicle accidents (MVAs); 4 patients had a history of an axial load or sports-related injury. All 3 patients involved in MVAs had posterior cruciate ligament tears consistent with posterior translation of the tibia. The non-MVA individuals had tears of the ACL with internal derangements similar to other ACL deficient knees, however, with more widespread osseous contusions., Conclusions: Patellotibial contusions are high-energy injuries resulting in cruciate ligament tears. These contusions occur exclusively in patients with ACL tears when individuals with a history of direct impaction to the knee are excluded. Axial loading of the extended knee may be an important mechanism of injury in these individuals.

Objective: The trochlear cleft is a recently described vertically oriented, low-signal cartilage lesion centered in the trough of the trochlear cartilage. The purpose of our study was to determine the incidence of clefts in an at-risk group of athletes and correlate these findings with clinical and physical examination results., Materials and Methods: Sixteen female collegiate volleyball players consented to bilateral knee evaluations, which consisted of history, physical examination, and magnetic resonance (MR) imaging. Two fellowship-trained musculoskeletal radiologists reviewed each MR study by consensus. The trochlear cartilage was considered to be either normal, at risk of developing a cleft, or meeting the previously described criteria for clefts. The Fisher exact test was used for categorical variables, and the Mann-Whitney U test was used for nonparametric continuous variable., Results: A total of 16 athletes (32 knees; 16 women; age range, 18-22 years; mean, 19.9 years) were enrolled in the study. Four knees (13%) in 3 athletes were diagnosed with a trochlear cleft; 6 knees (19%) in 4 athletes had clefts or were at risk of developing clefts. Among those players with unilateral cartilage lesions, 67% had contralateral abnormalities (P = 0.0783). Functional outcomes and physical examination findings were within normal limits for all athletes, with no difference noted between those with and without clefts., Conclusions: Elite athletes have a much higher incidence of trochlear clefts than the general population and are at risk of bilateral disease. Clefts are likely to be an incidental finding at MR imaging for unrelated symptoms.

Background: The modified International Knee Documentation Committee (Pedi-IKDC) Subjective Knee Evaluation Form has recently been shown to be valid, reliable, and responsive in a pediatric and adolescent population. The correlations between the Pedi-IKDC and quality-of-life-related health measures have not been studied in depth to determine how a knee injury affects patients in this age group. The purpose of this study was to examine the association between the Pedi-IKDC score and the Child Health Questionnaire (CHQ) in a group of pediatric patients with an anterior cruciate ligament (ACL) injury., Methods: A prospectively collected registry of patients with ACL injuries was searched to indentify all patients who had completed both the Pedi-IKDC and CHQ (CHQ-CF87) questionnaires. These were analyzed to determine significant correlations between domains of the CHQ and the Pedi-IKDC., Results: A total of 135 patients were included (80 male, 55 female) with a median age of 15.3 years (range, 13.1 to 17.2 y). The cohort included patients treated both operatively (120) and nonoperatively (15). The total Pedi-IKDC score was found to correlate with the majority of the CHQ including expected domains such as physical function (correlation coefficient = 0.64), bodily pain (0.7), and family activities (0.41), in addition to emotional role (0.45), mental health (0.46), self-esteem (0.45), and social limitations--physical (0.38) (P < 0.001 for all correlations)., Conclusions: Seven of the 12 domains on the CHQ are significantly correlated with the IKDC in adolescent patients with an ACL tear. Self-esteem, mental health, emotional role, and social limitations categories are significantly correlated with knee function suggesting that quality-of-life in this population is affected in domains outside of physical function and pain. A greater understanding of the psychosocial impact of injury may be of utility in these patients., Study Design: Level III cross-sectional study.

Background: Physical examination may be inconclusive in adolescents presenting with an acute traumatic knee effusion because of pain and guarding. The purpose of this study was to describe the magnetic resonance imaging (MRI) findings in adolescents with traumatic knee effusions and to compare injuries based on age, sex, and physeal maturity., Methods: All MRIs using a knee trauma protocol performed at our institution over a 2-year period were evaluated. One hundred thirty-one patients between the ages of 10 to 18 years of age with a clinical history of acute knee trauma and an effusion confirmed on MRI met our study inclusion criteria. They were divided into 2 age groups: 10 to 14 and 15 to 18 years old. Pathology was confirmed using clinical history, MRI, and any available surgical reports., Results: Of the 131 patients with an acute knee effusion, there were 59 patients in the younger group (10 to 14 y old) and 72 patients in the older group (15 to 18 y old). In the younger group, patellar dislocations (36%), anterior cruciate ligament (ACL) tears (22%), and isolated meniscus tears (15%) were the most common injuries. In the older group, ACL tears (40%), patellar dislocations (28%), and isolated meniscus tears (13%) were the most common injuries. ACL injuries represented 28% of injuries in males and 38% of injuries in females, whereas patellar dislocations represented 28% of injuries in males and 37% of injuries in females. There was a trend toward adolescents with active growth plates sustaining more patellar dislocations and adolescents with closed growth plates sustaining more ACL injuries. Forty-one percent of patients in this study underwent surgery., Conclusions: Patellar dislocation is a common injury in children who present with a traumatic knee effusion, especially in young adolescents and females. Adolescents presenting with a traumatic knee effusion should undergo MRI because of the high rate of positive findings missed by physical examination and plain radiographs that may warrant surgical repair or reconstruction., Level of Evidence: Level III.

Background: Magnetic resonance imaging (MRI) is a commonly used tool for the diagnosis of intra-articular knee pathologies. Although many studies have reported the accuracy of MRI in the adult population, fewer studies have investigated these tests in younger patients. Furthermore, these studies have shown a higher variability in both the sensitivity and the specificity of MRI for these knee injuries in this age group. Advancements in MRI technology, such as the 3-Tesla (3T) MRI magnet, have shown promising results for musculoskeletal injury diagnosis in adults. This study aims to evaluate 3 T MRI for the diagnosis of intra-articular knee pathologies in a pediatric and adolescent patient population., Methods: The records of 116 patients (119 knees) under the age of 20 years who underwent 3 T MRI studies of the knee and subsequent knee arthroscopy were reviewed retrospectively. The MRI report from the musculoskeletal radiology staff, the interpretation from the staff orthopedic surgeon, and the operative note dictations were compared, with a focus on meniscus and anterior cruciate ligament (ACL) pathologies. Seventeen orthopedic staff reads were not obtainable. Arthroscopy was used as the gold standard for diagnosis., Results: The average age at MRI exam was 16.0 years and at surgery was 16.2 years. Using the musculoskeletal radiologist interpretation, the sensitivity and the specificity of 3 T MRI were 81.0% and 90.9% for medial meniscus injuries, 68.8% and 93% for lateral meniscus injuries, and 97.9% and 98.6% for ACL injuries, respectively. The orthopedic surgeon's interpretation of 3 T MRI had a sensitivity and specificity of 75.7% and 92.4% for medial meniscus injuries, 69.8% and 98.3% for lateral meniscus injuries, and 100% and 98.6% for ACL injuries, respectively. Posterior horn tears had the greatest discrepancies., Conclusions: When performed on pediatric and adolescent patients, newer 3 T MRI studies have excellent accuracy for diagnosing ACL tears. These studies also show a higher accuracy for the diagnosis of medial meniscal tears than lateral meniscal tears., Level of Evidence: Diagnostic study--Level 2.

Purpose: To determine the magnetic resonance (MR) imaging appearances of osteonecrosis of the tibial plateau and perform quantitative analysis of the extent of the necrotic area., Materials and Methods: Twenty-eight patients (34 knees) with osteonecrosis were retrospectively evaluated using MR imaging and other modalities where available. A computerized image analysis program that allowed quantification of the lesion size was used to obtain measurements of the extent of involvement, which were then incorporated into each stage of the disease., Results: The MR imaging findings of osteonecrosis of the tibial plateau included subchondral regions of abnormal signal intensity (n = 28), a double-line sign (n = 11), and fractures (n = 9). Meniscal tears and cartilage abnormalities were disclosed in the affected knee compartment with an equal frequency (n = 17). The size of the necrotic lesion varied among different stages of the disease as follows: 6.8% to 15.7% (stage I); 6.5% to 59.3% (stage II); 23.5% to 61.3% (stage III); and 34.3% to 75% (stage IV). The extent of involvement was greater in stage II than that in stage I (P < 0.001) and in stage IV than that in stage III (P < 0.05), whereas the extent of involvement in stage III was not significantly greater than that in stage II (P > 0.05)., Conclusions: The MR imaging characteristics of osteonecrosis of the tibial plateau are variable. The association of osteonecrosis at this site with meniscal tears and cartilage abnormalities has important implications for pathogenesis of the disease as it relates to physical stress. Quantification of the lesion size provides precise information for optimal staging of the disease.

Objectives: To evaluate the relationship between T1 after intravenous contrast administration (T1Gd) and Delta relaxation rate (DeltaR1) = (1/T1(Gd) - 1/T1o) in the delayed Gadolinium-Enhanced MRI of cartilage (dGEMRIC) evaluation of cartilage repair tissue., Materials and Methods: Thirty single MR examinations from 30 patients after matrix-associated autologous chondrocyte transplantations of the knee joint with different postoperative intervals were examined using an 8-channel knee-coil at 3T. T1 mapping using a 3D GRE sequence with a 35/10 degrees flip angle excitation pulse combination was performed before and after contrast administration (dGEMRIC technique). T1 postcontrast (T1(Gd)) and the DeltaR1 (relative index of pre- and postcontrast R1 value) were calculated for repair tissue and the weight-bearing normal appearing control cartilage. For evaluation of the different postoperative intervals, MR exams were subdivided into 3 groups (up to 12 months, 12-24 months, more than 24 months). For statistical analysis Spearman correlation coefficients were calculated., Results: The mean value for T1 postcontrast was 427 +/- 159 ms, for DeltaR1 1.85 +/- 1.0; in reference cartilage 636 +/- 181 ms for T1 postcontrast and 0.83 +/- 0.5 for DeltaR1.The correlation coefficients were highly significant between T1 (Gd) and DeltaR1 for repair tissue (0.969) as well as normal reference cartilage (0.928) in total, and for the reparative cartilage in the early, middle postoperative, and late postoperative interval after surgery (R values: -0.986, -0.970, and -0.978, respectively). Using either T1(Gd) or DeltaR1, the 2 metrics resulted in similar conclusions regarding the time course of change of repair tissue and control tissue, namely that highly significant (P > 0.01) differences between cartilage repair tissue and reference cartilage were found for all follow-up groups. Additionally, for both metrics highly significant differences (P < 0.01) between early follow up and the 2 later postoperative groups for cartilage repair tissue were found. No statistical differences were found between the 2 later follow-up groups of reparative cartilage either for T1 (Gd) or DeltaR1., Conclusion: The high correlation between T1 (Gd) and DeltaR1 and the comparable conclusions reached utilizing metric implies that T1 mapping before intravenous administration of MR contrast agent is not necessary for the evaluation of repair tissue. This will help to reduce costs, inconvenience for the patients, simplifies the examination procedure, and makes dGEMRIC more attractive for follow-up of patients after cartilage repair surgeries.

Introduction: Cartilage defects are common pathologies and surgical cartilage repair shows promising results. In its postoperative evaluation, the magnetic resonance observation of cartilage repair tissue (MOCART) score, using different variables to describe the constitution of the cartilage repair tissue and the surrounding structures, is widely used. High-field magnetic resonance imaging (MRI) and 3-dimensional (3D) isotropic sequences may combine ideal preconditions to enhance the diagnostic performance of cartilage imaging.Aim of this study was to introduce an improved 3D MOCART score using the possibilities of an isotropic 3D true fast imaging with steady-state precession (True-FISP) sequence in the postoperative evaluation of patients after matrix-associated autologous chondrocyte transplantation (MACT) as well as to compare the results to the conventional 2D MOCART score using standard MR sequences., Material and Methods: The study had approval by the local ethics commission. One hundred consecutive MR scans in 60 patients at standard follow-up intervals of 1, 3, 6, 12, 24, and 60 months after MACT of the knee joint were prospectively included. The mean follow-up interval of this cross-sectional evaluation was 21.4 +/- 20.6 months; the mean age of the patients was 35.8 +/- 9.4 years. MRI was performed at a 3.0 Tesla unit. All variables of the standard 2D MOCART score where part of the new 3D MOCART score. Furthermore, additional variables and options were included with the aims to use the capabilities of isotropic MRI, to include the results of recent studies, and to adapt to the needs of patients and physician in a clinical routine examination. A proton-density turbo spin-echo sequence, a T2-weighted dual fast spin-echo (dual-FSE) sequence, and a T1-weighted turbo inversion recovery magnitude (TIRM) sequence were used to assess the standard 2D MOCART score; an isotropic 3D-TrueFISP sequence was prepared to evaluate the new 3D MOCART score. All 9 variables of the 2D MOCART score were compared with the corresponding variables obtained by the 3D MOCART score using the Pearson correlation coefficient; additionally the subjective quality and possible artifacts of the MR sequences were analyzed., Results: The correlation between the standard 2D MOCART score and the new 3D MOCART showed for the 8 variables "defect fill," "cartilage interface," "surface," "adhesions," "structure," "signal intensity," "subchondral lamina," and "effusion"-a highly significant (P < 0.001) correlation with a Pearson coefficient between 0.566 and 0.932. The variable "bone marrow edema" correlated significantly (P < 0.05; Pearson coefficient: 0.257). The subjective quality of the 3 standard MR sequences was comparable to the isotropic 3D-TrueFISP sequence. Artifacts were more frequently visible within the 3D-TrueFISP sequence., Conclusion: In the clinical routine follow-up after cartilage repair, the 3D MOCART score, assessed by only 1 high-resolution isotropic MR sequence, provides comparable information than the standard 2D MOCART score. Hence, the new 3D MOCART score has the potential to combine the information of the standard 2D MOCART score with the possible advantages of isotropic 3D MRI at high-field. A clear limitation of the 3D-TrueFISP sequence was the high number of artifacts. Future studies have to prove the clinical benefits of a 3D MOCART score.

The anterior cruciate ligament (ACL) is one of the most frequently torn ligaments of the knee. With more than 100,000 ACL reconstructions performed yearly in the United States, evaluation of ACL grafts with magnetic resonance imaging is a common occurrence in daily clinical practice. Anterior cruciate ligament reconstructions vary from single bundle, double bundle, selective bundle, and physeal-sparing techniques. Complications of ACL graft reconstructions include graft tears, graft laxity, arthrofibrosis, and hardware failure or migration. This article offers a comprehensive review of ACL reconstruction for the consulting radiologist.

Magnetic resonance imaging has evolved into a highly accurate modality in detecting meniscal injuries and provides the essential anatomic detail to help guide treatment options in this age of meniscal preservation. Accurate interpretation requires a thorough understanding of meniscal anatomy and function, anatomic variants, technical factors, typical appearance of tear patterns on magnetic resonance imaging, associated ligamentous injuries, causes of misdiagnoses, and the importance of correlation with the clinical examination.

Background: Fractures of the femur are severe injuries that quickly attract the physician's attention. Previous reports have shown that injuries to the ipsilateral knee can occur. In most cases, such injuries were diagnosed on delay. Excluding cases in which a knee injury was apparent already at admission, we sought to investigate the number and severity of initially undetected lesions to the knee concomitant with a femoral shaft fracture and give an overview of the literature referring to these combined injuries., Methods: Charts and X-rays of patients treated for a femoral shaft fracture from January 2000 until December 2007 were reviewed. Patients, in whom any other injury of the affected limb apart from a midshaft femoral fracture was initially diagnosed, were excluded. Also patients, in whom an injury to the knee had been diagnosed at admission, were excluded., Results: Fifty-three patients with 55 midshaft femoral fractures were available for analysis. An injury to the knee was diagnosed in three cases (5%). There was one partial tear of the posterior cruciate ligament and two grade two lesions of the medial meniscus. All lesions were conservatively treated without any after-effects., Conclusion: Physical examinations under anesthesia, arthroscopy and magnetic resonance imaging have shown lesser correlation among each other than one would expect. More severe injuries to the knee with femoral shaft fractures are more likely to be detected early, than minor ones. Pain about the knee communicated by the awake patient should be the indication for further apparative examination by magnetic resonance imaging or arthroscopy.

Nonunion of anterior tibial spine of tibia in children is quite rare, but it could be associated with significant instability of the knee as it involves the fixation of anterior cruciate ligament. We report one case in which open reduction and internal fixation was carried out with good functional results. A literature review was performed to identify the cases reported of tibial eminence nonunion in children.

Objectives: Bicondylar tibial plateau fractures featuring extensive articular involvement have a record of mixed clinical results. Recent discussion has focused on the significance of a posteromedial articular fragment in bicondylar injuries. This fragment has often gone unrecognized or has not been addressed. The posteromedial fragment is defined as any posteriorly based articular fracture of the medial plateau with the fracture line exiting the medial cortex. This study is designed to produce a detailed description of the incidence, size, and shape of this fracture, as this may be helpful in driving the choice of both approach and fixation for these injuries. Furthermore, a better understanding of this fracture's morphology may lead to a better ability to model the biomechanical reliability of laterally based locking fixation in securing the reduction of this fracture fragment., Design: Retrospective study of patient records and computed tomography scans., Setting: Level I university regional trauma center., Patients: All patients treated for bicondylar tibial plateau fracture from January 1, 2002, through August 31, 2007., Results: One hundred forty-eight patients were identified in the 5.5-year period, and 111 had complete computed tomography records (75%). Of 111 bicondylar tibial plateau fractures analyzed, this fragment occurred in 65 cases (59% incidence) and on average accounted for 25% of the total tibial plateau joint surface. There was greater than 5 mm of articular displacement in 55% of cases. The posteromedial fragment exhibits a vertical fracture pattern (average sagittal angle 73 degrees), suggestive of shear instability and vertical displacement., Conclusions: Given the high frequency, significant portion of the joint involved, significant displacement, and pattern suggestive of instability, surgeons need to be cognizant of this pattern and may need to consider directly reducing and fixating this fragment through a posteromedially based approach. Overall morphologic findings of the posteromedial fragment are highly consistent with other recent data on this pattern. This information may also be useful in modeling fracture fixation for future study.

Objective: To analyze the prevalence and describe the magnetic resonance imaging (MRI) features of central hole tear (CHT) of the discoid meniscus., Methods: Thirty-six patients with arthroscopically proven CHT who underwent knee MRI were included. We retrospectively reviewed the clinical history and evaluated the MRI findings which have been known as the findings of bucket-handle tear (BHT) and osteoarthritis., Results: A CHT accounts for 15% of discoid meniscus tears. In all patients, CHT involved the lateral meniscus. Of 36 patients, 28 (78%) had not any history of trauma to the knee. Intercondylar notch sign, coronal truncation sign, absent bow tie sign, and flipped meniscus sign were seen in 36 (100%), 35 (97%), 34 (94%), and 10 patients (28%), respectively. In addition, 26 (72%), 21 (58%), and 17 (47%) of 36 patients showed osteophytes formation, chondral lesion, and subchondral bone change, respectively. Of these 36 patients, 23 (64%) and 22 (61%) demonstrated increased signal intensity in the meniscus on proton density-weighted image and irregularities of the margin of the residual menisci, respectively., Conclusions: Although a CHT had many of the MRI features of BHT, it was usually accompanied by changes of osteoarthritis. Presence of degenerative change, absence of trauma, and presence in the lateral meniscus are features that favor a CHT over a BHT of the meniscus.

Unlabelled: Articular cartilage injuries and loose bodies have been associated with patellar dislocations. At the time of patellar realignment surgery (PRS), direct intraarticular visualization of the structures of concern may be limited with the use of a small arthrotomy. Concomitant diagnostic arthroscopy can improve the identification of intraarticular abnormalities, both patellofemoral and nonpatellofemoral, because of the better field of view., Purpose: This report details the findings from knee arthroscopy performed concomitantly with PRS in adolescents., Methods: All patients underwent knee arthroscopy and open PRS for patellar instability, performed by a single surgeon, during a 4-year period. Patient demographics, knee history, clinical examination, operative findings, and treatment details were collected on all patients., Results: : Thirty-eight patients (mean age, 14.9 years; 41 knees) were included in this analysis. Patellar osteochondral lesions were present in 30 knees (73%; mean size, 112 mm). Femoral lesions were documented in 11 knees (23%; mean size, 81 mm). Loose bodies were present in 6 knees (15%). In 8 patients (20%), an additional 11 nonpatellofemoral diagnoses were made at the time of arthroscopy: lateral tibiofemoral chondroses (n = 4), medial meniscal tear (n = 2), lateral meniscal tear (n = 2), discoid lateral meniscus (n = 1), partial anterior cruciate ligament tear (n = 1), and medial tibiofemoral chondrosis (n = 1). Because of these findings, 5 additional procedures were performed in 4 patients: partial lateral meniscectomy (n = 2), medial meniscal repair (n = 1), discoid meniscus saucerization (n = 1), and staged distal femoral valgus-correcting osteotomy (n = 1)., Conclusions: By performing concomitant knee arthroscopy at the time of PRS, we were able to identify significant tibiofemoral abnormality in 4 patients, which would have been missed with direct inspection by a limited arthrotomy at the patellofemoral joint. In addition, precise evaluation of the patellofemoral joint permits customization of the PRS and aids in establishing appropriate patient expectations postoperatively. We advocate diagnostic knee arthroscopy at the time of PRS in adolescents to identify all intraarticular abnormalities and to optimize discussions with the patient and the caregivers on the long-term prognosis of the knee., Significance: Arthroscopic inspection of the knee at the time of PRS permits identification of abnormality that is not routinely visual by using open arthrotomy. Twenty percent of patients had additional pathological findings; of these patients, 50% underwent an additional surgical procedure.

Objectives: Opioid receptors are expressed on peripheral nerve endings and opioid peptides (beta-endorphin, END) are produced in various immune cells of synovial tissue after knee trauma. Because corticotropin-releasing hormone (CRH) acts through its receptors on END-containing immune cells, this randomized controlled trial investigated whether the intra-articular (IA) injection of CRH reduces postoperative pain intensity and supplemental analgesic consumption in patients undergoing arthroscopic knee surgery., Methods: Patients were randomly assigned to one of the following IA and IV treatments: group saline (SAL) (n=17) received isotonic SAL IA and 10 microg CRH IV; group CRH (n=16) received 10 microg CRH IA and SAL IV; group CNL (n=18) received 10 microg CRH plus 0.12 mg naloxone IA and SAL IV. Patients pain intensity at rest and during exercise, cortisol plasma concentrations as well as supplemental analgesics were documented. Immunohistochemistry analyzed colocalization of CRH receptors and END., Results: IA but not IV CRH resulted in a significant but short lasting reduction of postoperative pain under both resting and exercise conditions without changes in cortisol plasma concentrations. Coadministration of naloxone reversed this pain reduction under resting but not exercise conditions. The majority of CRH receptor expressing cells contained END within synovial tissue., Discussion: In conclusion, this first clinical trial provides preliminary evidence for a short but not robust analgesic effect of a single dose of IA CRH in patients undergoing arthroscopic knee surgery. Further clinical studies will have to examine different doses of IA CRH-induced analgesia and to support the involvement of opioid peptides.

Objective: The purpose of this study was to give a detailed description of recovery benchmarks that occur in patients whose therapy after partial meniscectomy knee arthroscopy consists of a home program of exercise. These benchmarks can be used as a basis for clinicians to compare improvements to individual patients who receive supervised care., Design: Thirty-nine patients (five females, mean age = 41) who underwent an uncomplicated arthroscopic partial meniscectomy were included. Test sessions occurred at 5 and 50 days after surgery. Outcome measures included: 1) Hughston Clinic knee self-assessment questionnaire; 2) EQ-5D Tariff for assessment of quality of life; 3) number of days taken to return to work after surgery; 4) knee passive range of motion; and 5) knee swelling assessed by evaluation of knee circumference. Stepwise regression analysis was used to evaluate factors that might have influenced the amount of pre- to posttest change in the outcome measures (the benchmarks) during the first 7 wks after surgery. The factors used in this analysis were: 1) age, 2) body mass index, 3) period from injury to surgery, and 4) the baseline value of the variable to be examined (except for return to work, where we used a score estimating the challenge to the knee offered by work)., Results: None of the factors considered (age, body mass index, period from injury to surgery, stressfulness of the work on the knee) affected the number of days taken to return to work. Baseline scores affected change in all the other outcomes, and knee girth change was also affected by body mass index. Regression equations are presented where suitable for the benchmarks presented., Conclusions: Quick recovery occurs in these patients when only a home exercise program is given. This paper highlights the utility of using historical control group data instead of test-retest analysis of measurement error in evaluating patients whose recovery with a home exercise program is rapid. Of the variables analyzed in this study, quality of life and knee self-assessment changes offer the most useful benchmarks for evaluating treatment effectiveness.

Objective: This study was designed to evaluate the postimpact response of the articular cartilage in the rabbit knee after a single traumatic episode., Design: A novel servo-controlled Rabbit Impact Test System (RITS) was developed to apply a well-defined trauma to the femoral condyle in the rabbit knee. The RITS was first used in an in vitro study to determine an appropriate stress to cause cartilage damage without bone fracture. Viable rabbit knees (n = 18) were impacted with stresses of 15 to 50 MPa at a stress rate of 420 MPa/s, the latter corresponding to joint impact rates commonly seen in sports injuries and vehicular accidents. Based on the in vitro study, we performed an in vivo study by impacting the knees of rabbits (n = 9) with a 35 MPa peak stress at a stress rate of 420 MPa/s. The articular cartilage in these knees was analyzed at 0 and 3 weeks after impaction., Setting: Center for Laboratory Animal Services, Hospital for Special Surgery., Subjects: A total of 27 New Zealand White rabbits were used in this study., Intervention: A rabbit's knee was rigidly immobilized in the adjustable frame of the RITS. A small incision on the knee exposed the lateral condyle and the impactor was positioned perpendicular to the surface of the condyle. The lateral femoral condyle of the left knee was impacted, whereas the right knee was sham operated and used as a control., Main Outcome Measurements: Visual matrix damage, cell viability, and microscopic matrix damage was assessed., Results: In the in vitro study, matrix damage was observed at stress magnitudes > or =30 MPa. However, cell death was initiated at approximately 20 MPa at the articular surface and increased in depth with increasing stress magnitude (2.8 +/- 2% thickness/MPa,). In the in vivo study, visible surface damage was observed immediately after impaction but not at 3 weeks after impaction. At 3 weeks, the articular cartilage showed significant arthritic changes (matrix damage, chondrocyte death, and proteoglycan loss) typical of late-stage osteoarthritis., Conclusions: Our novel impact test system was able to accurately apply a quantifiable stress magnitude at a constant stress rate to rabbit femoral condyles in the in vitro and in vivo settings. At the time of impaction, the extent of cell death depended with the intensity of trauma (stress magnitude) in which complete cell death was observed in the impacted site at >40 MPa. Under in vivo conditions, the test system was able to consistently produce superficial matrix damage and cell death at 35 MPa stress magnitude at the time of impaction. This resulted in cartilage "arthritic" changes by 3 weeks postinjury.

Incaprettamento is a ritualized form of ligature strangulation often associated with the Italian Mafia. The hallmarks include ligature strangulation and binding of the body in a highly stereotyped fashion. The bindings include tying the wrists and ankles together, with the body in the prone position (similar to "hogtying"), and an additional ligature encircling the neck and attached to the bindings of the extremities. The binding of the body may be performed after death is inflicted by ligature strangulation, or it may be associated with self-strangulation, as shown by the arrangement of ligatures and the position of the body. A case with great similarities to incaprettamento, in which the body was exhumed from a grave in East Timor, is described in detail. However, in addition to prone-position binding and a hyoid fracture, chopping wounds of a knee and blunt trauma to the posterior torso were found. The implication of these wounds is discussed in relation to incaprettamento.

Objective: The purpose of this study is to identify and characterize the nature of internal knee derangement associated with ipsilateral femur fractures., Design: A prospective consecutive investigation with the musculoskeletal radiologist being blinded to the clinical examination., Setting: A certified Level I trauma center., Patients: All adult (skeletally mature) patients with femur fractures resulting from blunt traumatic injury were included. Patients with penetrating, periprosthetic, pathologic, or previous femur fractures were excluded. In addition, all patients with previous knee injuries or previous knee surgery were excluded. Of the fifty-one patients with diaphyseal femur fractures originally enrolled in this investigation, fifteen were excluded by protocol and eleven were unable to obtain timely MRI studies., Interventions: All patients were evaluated initially according to Advanced Trauma Life Support protocol. When appropriate, skeletal traction was used as provisional fracture stabilization. In most cases, however, operative fixation was performed immediately. In one case open reduction internal fixation was performed. In the remainder, fracture fixation with an anterograde ( = nineteen) or retrograde ( = seven) intramedullary nail was used., Outcome Measure: After surgical fixation, twenty-five patients with twenty-seven knees were examined clinically and with an MRI., Results: Five anterior cruciate ligament and two posterior cruciate ligament injuries were discovered (19 percent and 7 percent, respectively). Four complete (Grade 3) medial meniscus tears (15 percent) and seven complete lateral meniscus tears (26 percent) were identified by postoperative MRI studies. The medial collateral ligament was injured in eleven knees (41 percent), with five (19 percent) identified as complete (Grade 3) injuries. The lateral collateral ligament was also injured in eight knees (30 percent); in half (15 percent) the injury was complete. Bone contusions (periarticular infractions of cortical and medullary trabecular bone) were noted in eight (30 percent) tibia (equally divided between medial and lateral compartments) and in 17 (63 percent) femurs (also equally divided between medial and lateral condyles)., Conclusion: Given the large number of soft tissue injuries about the knee, it would be prudent to emphasize the importance of a thorough intraoperative examination once the femur fracture has been stabilized. Additionally, there should be a low threshold to obtain an MRI if the postoperative clinical examination suggests an associated knee injury. Bone bruises, which can only be identified by MRI studies, are increasingly being acknowledged as a source of persistent symptoms.

Magnetic resonance imaging (MRI) is an excellent modality for imaging the pediatric knee because of its superb soft-tissue contrast, multiplanar capability, and lack of ionizing radiation. The knee is the most common joint imaged by MRI in the pediatric population. The majority of studies are performed on older children or adolescents with pain and/or known trauma. There are variations of injury and patterns of injury that are unique to children. The knee of a child also may be studied by MRI for other indications, including tumor, inflammatory disease, and developmental abnormalities. It is important to have a systematic approach to analysis of the knee MR images. Analysis should include individual attention to bones, articular cartilage, muscles and tendons, soft tissues, neurovascular bundle, joint space, fluid collections, ligaments, and menisci.

Salter-Harris Type V epiphyseal injury is relatively uncommon. The authors present a case involving the proximal tibia diagnosed both by radiologic and histologic findings. The findings suggest that Salter-Harris Type V injury can be a possible outcome when the disappearance of the physeal plate is reported in a patient who has great physical activity in childhood, even if the patient has suffered from no major injury.

Introduction: Subjective questionnaires, completed by the patient, are often used to document the status of a disabled knee. The purpose of this study was to validate the Hughston Clinic subjective knee questionnaire by describing how knee kinematics and kinetics correlated to subjective knee scores after knee injury and surgery., Methods: Five groups were studied: patients 2 (N = 37), 6 (N = 37), and 24 (N = 8) wk after ACL reconstruction (ACLR); patients with a chronic PCL deficiency (N = 9); and uninjured controls (N = 8). A three-dimensional motion analysis system and force platform were used to measure flexion angles and knee moments during level walking and stair climbing., Results: Hughston Clinic questionnaire scores were significantly correlated to mechanical descriptors measured during stair ascent and descent in the 2- and 6-wk ACLR groups (P < 0.05). The Hughston Clinic questionnaire score was correlated to several kinematic variables in the ACL reconstructed knee at 24 wk postoperative, e.g., knee flexion during walking. In the PCL deficient group, the Hughston Clinic questionnaire score was correlated with several kinetic measures, e.g., the peak moment (knee extensors). The Hughston Clinic questionnaire score was not correlated to knee mechanics in the control group., Conclusion: The Hughston Clinic questionnaire score has been shown to be valid in this study as it reflects some mechanical descriptors during activities of daily living in the first 6 wk post ACL reconstruction. The questionnaire also provides information on gait modifications by people coping with knee injuries.

Purpose: The purpose of this study was to assess the degree of meniscal movement during knee flexion on MR images and to correlate it with the severity of cartilage damage in the femorotibial joint., Method: Sagittal MR images were obtained at extension and 45 degrees of flexion in 35 knees. A shortening ratio in the distance between the anterior and posterior horns at 0-45 degrees of knee flexion was calculated in each meniscus and was correlated with the degree of cartilage abnormality in the femorotibial joint., Results: The shortening ratio of the meniscus was reduced in knees with cartilage abnormality in the femorotibial joint. The shortening ratio of the medial meniscus was inversely correlated with the degree of cartilage abnormality in the medial femoral condyle and with that in the medial tibial plateau., Conclusion: Restricted shortening ratio of the meniscus may be related to cartilage damage in the femorotibial joint.

Purpose: We have previously shown that the combination of low-intensity resistive exercise and moderate vascular occlusion induces in humans a marked increase in growth hormone secretion and muscular hypertrophy. The present study investigated the effects of vascular occlusion on the size of thigh muscles in patients who underwent an operation for the reconstruction of the anterior cruciate ligament to see whether it attenuates the disuse muscular atrophy without any exercise combined., Methods: Two sessions of occlusive stimulus, each consisting of five repetitions of vascular occlusion (mean maximal pressure, 238 mm Hg) for 5 min and the release of occlusion for 3 min, were applied daily to the proximal end of the thigh from 3rd to 14th days after the operation. Changes in the cross-sectional area (CSA) of thigh muscles were analyzed with magnetic resonance images taken on the 3rd and 14th day after the operation., Results: Without occlusive stimulus (control), the CSAs of knee extensors and flexors decreased by 20.7 +/- 2.2% and 11.3 +/- 2.6% (mean +/- SEM, N = 8), whereas with the occlusive stimulus, they decreased by 9.4 +/- 1.6% and 9.2 +/- 2.6% (N = 8), respectively. The relative decrease in CSA of knee extensors was significantly (P < 0.05) larger in the control group than in the experimental group., Conclusion: The results indicate that the occlusive stimulus effectively diminishes the postoperation disuse atrophy of knee extensors.

Indirect signs of anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI) include bony contusions in the lateral femoral condyle and the posterior portion of the lateral tibial plateau. This study was undertaken to assess the value of single photon emission tomography (SPET) in the diagnosis of ACL injury by examining the uptake pattern in the distal femur and the proximal tibia. Thirty-five patients were examined using SPET, MRI and arthroscopy. Seventeen patients were found to have ACL tears on arthroscopy. The duration of symptoms was 4 days to 10 years (mean 26.4 months). MRI and SPET images were analysed retrospectively without information from arthroscopic examination. Radionuclide uptake in the lateral femoral condyle and the posterior lateral tibial plateau was considered an indirect sign of ACL injury on SPET. We evaluated the diagnostic value of indirect signs of ACL injury obtained on SPET by comparing these findings with arthroscopic and MRI results. Fifteen of 17 patients with ACL injury showed indirect signs on SPET. The sensitivity, specificity, positive predictive value and negative predictive value for indirect signs of ACL injury were 88%, 56%, 65% and 83% on SPET and 59%, 94%, 91% and 71% on MRI, respectively. However, despite the higher sensitivity of indirect signs on SPET than on MRI, the overall diagnostic value of MRI is better than that of SPET. In the clinical setting, indirect signs of ACL injury may be of value in interpreting incidental findings on SPET.

The aim of this study was to ascertain whether knee SPET can localize lesion sites in patients with internal derangements of the knee. We performed knee SPET as a pre-arthroscopic examination in 63 consecutive patients. SPET imaging was performed with a triple-headed SPET camera 4 h after the injection of 99Tcm-methylene diphosphonate. Arthroscopic diagnoses were as follows: 28 medial meniscus injuries, 24 lateral meniscus injuries, 31 anterior cruciate ligament (ACL) injuries, three posterior cruciate ligament injuries and one medial collateral ligament injury. Of 30 patients with crescent-shaped increased activity at the medial tibial plateau, 22 had medial meniscus injuries (positive predictive value: PPV 73%); of 17 patients with crescent-shaped activity at the lateral tibial plateau, 13 had lateral meniscus injuries (PPV 76%). Of 18 patients with increased activity at ACL attachment sites (primary sign), 17 had ACL injuries (PPV 94%). Of 27 patients with increased activity at bone impaction sites of ACL injury (secondary sign), 22 had ACL injuries (PPV 81%). Of 32 patients who had either a primary or secondary sign, 26 had ACL injuries (PPV 81%). We conclude that knee SPET is very useful in the management of internal derangements of the knee, particularly in determining the need for arthroscopy by localizing lesion sites.

We sought to evaluate the antiinflammatory effects of synthetic human beta-endorphin (SHB) when injected into the canine knee joint. Sixteen healthy dogs, aged 1-2 yr, were selected. SHB was injected pre- and postinjury into each knee. The sample size was n = 32 after a randomized factorial arrangement; 2 x 4 with four cases per treatment being performed. Factors considered were: Factor A with two levels: A1 = Preinjury and A2 = Postinjury; Factor B (SHB dose) with four levels: B1 = Control, B2 = 250 micrograms, B3 = 500 micrograms, B4 = 1000 micrograms. The control group received 0.9% NaCl solution. Anesthesia was induced with intravenous thiopental, 14 mg/kg, and acepromazine, 0.5 mg/kg. Injury was produced with an intraarticular injection of 4 mL HCl 0.5 M, which was left in situ for 20 min. Inflammation was measured using the 610 nm absorbency of Evans blue extravasate in biopsy specimens. Histopathologic studies were performed on each knee. We found that beta-endorphin has a clear, dose-related, antiinflammatory effect, reducing the tissue extravasation of Evans blue and its absorbency, especially with large doses. This finding was consistent with the histopathologic observations. We conclude that SHB has an antiinflammatory effect. It is still not clear which mechanisms inhibit polymorphonuclear cell adhesion to vascular endothelium or cell and plasmatic protein extravasation.

A one-engined light aircraft struck the ground at high terminal velocity, producing a large impact crater. The captain and the five passengers were killed, their bodies being dismembered into several hundreds of mostly small tissue pieces. Besides identification, the pathologic investigation dealt with the morphologic features of high-speed impact trauma. In detail, the following peculiarities were found: detachment of the skin with typically sharp-edged margins and sometimes striaelike tears due to overstretching, intracutaneous hemorrhages according to the pleats of the clothing, a strikingly good preservation of the long peripheral nerves as a consequence of their especially high resistance to tearing, thin-layer hemorrhages under articular cartilages, separation of the penis in combination with detachment of its skin and hematoma of the glans or of the prepuce, subepicardial and subendocardial hemorrhages, petechiae of the conjunctivae and of the serous membranes (for example, parietal pleura), and petechial hemorrhages in the mucous membranes of larynx and trachea. Because of immediate circulatory arrest, these numerous hemorrhages must be attributed to mere local tissue bruising at the moment of impact.

Objective: Bone contusions are frequently found in association with complete tears of the anterior cruciate ligament (ACL) and can be a helpful secondary sign in diagnosis. We compare the frequency, location, and significance of bone contusions in complete and partial ACL tears., Materials and Methods: Twenty-nine patients with complete and 42 patients with incomplete tears of the ACL were examined by MRI for the presence of accompanying bone contusions within 1 month of injury., Results: Bone contusions were found in 72% of the complete ACL tears but in only 12% of the partial tears. Of the partial ACL tears with accompanying contusions, 80% were high grade injuries that eventually went on to complete rupture within 6 months. Only 16% of the partial ACL injuries without bone contusion progressed to complete rupture at 1-2 year follow-up. There was no difference between the bone contusions of partial and complete tears in terms of general appearance and location. They were predominantly in the lateral compartment (90%) and had a specific predilection for the mid portion of the lateral femoral condyle and the posterior portion of the lateral tibial plateau, often occurring in tandem., Conclusion: Bone contusions occur with much less frequency in partial ACL tears than in complete tears but their presence in partial rupture favors a high grade tear that is likely to become complete.

We describe a case of a major trauma to a knee joint with extensive destruction of soft tissues, ligamentary structures, and bone loss. Although in extensive trauma of the knee, conservation and reconstruction of the joint structures is usually attempted, the massive destruction and gross contamination in this case prompted us to perform a primary arthrodesis in order to avoid life-threatening complications and to obtain early functional recuperation of the involved limb.

Rationale and Objectives: The differences in imaging characteristics between conventional and fast spin-echo studies of the skeletons of children and young adults were evaluated., Methods: Concurrent conventional and fast spin-echo studies of 23 patients were compared by measuring signal intensity, contrast, and, subjectively, conspicuity of normal and abnormal musculoskeletal structures., Results: Fast proton-density-weighted images had lower signal-to-noise ratios of muscle, fat, and physeal, epiphyseal, and articular cartilage. Using more than three echoes for proton-density images resulted in blurring and decreased lesion conspicuity. On fast T2-weighted images, there was greater conspicuity of normal cortex, ligaments, and muscle; but less contrast between fat and water because of a higher signal-to-noise ratio of fat. When both sequences were obtained with similar image quality, fast spin-echo was 40% faster., Conclusion: Fast spin-echo studies allows faster imaging, but can have blurring on proton-density-weighted images and decreased fat-water contrast on T2-weighted images.

Objective: We sought to define the MRI appearance of both complete and partial-thickness tears of the posterior cruciate ligament (PCL) and to describe patterns of injury and associated MRI findings., Materials and Methods: Three radiologists retrospectively reviewed MR images and medical records on 32 patients with PCL tears (15 complete, 17 partial) and correlated MRI findings to results of clinical testing and surgery., Results: The PCL had indistinct margins in 27 (84%) of 32 patients and was abnormally thick in 25 (78%) patients. In 31 (97%) patients, the torn PCL showed increased signal intensity on both T1- and T2-weighted pulse sequences. Although there was no statistically significant difference between patients with complete tears and those with partial tears with regard to thickness, margination, and signal intensity of the PCL, MR images in patients with complete tears were more likely to show focal areas of ligamentous discontinuity (10 of 15 cases) (p = 0.01). Associated knee injuries were seen in 21 (66%) patients and were seen more frequently in patients with complete PCL tears (p = 0.015). Bony injury (n = 11, 34%) and tears of the medial collateral ligament (n = 13, 41%) and menisci (n = 10, 31%) were common. No specific pattern of bony injury was found., Conclusion: Posterior cruciate ligament tears can be diagnosed readily by multiplanar MRI using both morphological and signal intensity characteristics. Although differentiation between complete and partial-thickness PCL tears by MRI criteria alone is more problematic, complete tears are more likely to show focal areas of discontinuity and partial tears are more likely to show at least some intact fibers.

During a 1-year period, data on all acute injuries treated at emergency departments were entered into a registry; of these injuries, 6% involved the knee joint. The patients were followed until a definite diagnosis was established. The rate of anterior cruciate ligament injuries and meniscus tears was, respectively, 0.3 and 0.7 (injuries per 1,000 inhabitants per year). The rate of dislocations of the patellofemoral joints was equal to the rate of anterior cruciate ligament injuries. Ten percent of the cases involved ligament injuries, and isolated ruptures of the anterior cruciate ligaments were twice as common as combined lesions of this ligament. Injuries of both the collateral ligament and the meniscus represented 6% of the cases. In most age groups male patients predominated, but the frequency of anterior cruciate ligament injuries was similar in both sexes, while the frequency of collateral ligament injuries and meniscus tears varied according to both gender and age. Only 27% of the injuries were associated with sports activities, but they were found twice as often among athletes than people injured in nonathletic accidents. Ruptures of the collateral ligament and anterior cruciate ligament were four and seven times more common among athletes, respectively, while athletes sustained fewer meniscus tears than people involved in nonathletic activities. Half of the patients needed further care after primary treatment, and 18% were primarily (65%) or secondarily (35%) admitted to in-patient care. Operative treatment, including arthroscopic examination, was performed in 20% of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Sixteen cases of physeal injury of the hip or the knee were reviewed, with an average follow-up observation of 23 years and 8 months. Obstetric lesions were present in four cases. The average patient's age at injury was 8 years and 6 months, whereas it was 32 years and 3 months at follow-up observation. All our cases but three were treated nonoperatively. According to our evaluation criteria, eight patients had a good result, three fair, and five poor. A lower limb discrepancy ranging from 1.5 to 6 cm was present in seven patients. Either varus or valgus angulation of the knee was observed in three patients, but was marked in only one. Four patients had radiographic signs of osteoarthritis and all but one, had had a type III or IV injury. The highest number of good results was observed in proximal femur injuries, whereas the highest number of poor results was found in those of the distal femur. The final result seems to be closely related, in distal femoral lesions, to the type of physeal injury according to Salter and Harris and, in proximal tibial lesions, to the quality of reduction. In obstetric lesions, the results are unpredictable because even good short-term results may deteriorate during skeletal growth.

Two patients with sports-related knee injuries underwent magnetic resonance (MR) imaging, which demonstrated intracapsular fractures and effusions with a signal pattern characteristic of lipohemarthrosis. Four distinct signal bands were identified: superior band representing floating fat, a central band containing serum, an inferior band of dependent red blood cells, and a thin band representing chemical shift artifact at the interface of serum and floating fat.