Snowboarding injuries: a review of the literature and an analysis of the potential use of portable ultrasound for mountainside diagnostics.

Snowboarding has become a popular recreational and professional sport. Participants suffer a variety of injuries, especially of the extremities, that require medical evaluation. This article reviews the reported injuries to both leisure and elite athletes. To many, an injured extremity requires travel to a medical facility for accurate evaluation. Musculoskeletal ultrasound is an accurate and portable technology that can be used for real time, mountainside diagnoses of these injuries.

Normal and acutely torn posterior cruciate ligament of the knee at US evaluation: preliminary experience.

PURPOSE: To determine the ultrasonographic (US) findings of normal and acutely torn posterior cruciate ligament (PCL) of the knee and evaluate the usefulness of US in the injured PCL. MATERIALS AND METHODS: US images were obtained in 30 knees in 15 asymptomatic volunteers as a control group and in 35 patients clinically suspected of having an acute PCL injury. Only the distal half of the PCL was evaluated. Of the 35 patients, 28 had their PCL status confirmed: 13 had a normal PCL at magnetic resonance (MR) imaging plus clinical examination, and 15 had a torn PCL at either MR imaging and surgery or MR imaging and clinical follow-up. RESULTS: Normal PCLs were homogeneously hypoechoic, with a well-defined posterior border. Torn PCLs were heterogeneously hypoechoic (12 [80%] of 15 patients), with an indistinct posterior margin (11 [73%] of 15 patients). Torn PCLs were significantly thicker (range, 12.0-20.0 mm; mean, 15.6 mm +/- 2.5 [SD]; P <.01), as compared with normal PCLs in 13 patients (range, 3.8-5.8 mm; mean, 4.6 mm +/- 1.0; P <.01) and in the volunteers (range, 3.7-6.2 mm; mean, 4.5 mm +/- 1.2; P <.01). CONCLUSION: An acutely torn PCL thickens (>10 mm), loses its sharply defined posterior border, and has a heterogeneously hypoechoic appearance. US may be useful as a screening examination for patients suspected of having PCL injury and for deciding whether to perform more expensive MR imaging or surgical intervention.

Ultrasonography of the shoulder.

Musculoskeletal ultrasound (MSUS) is an important modality in evaluating shoulder disease. Following a baseline shoulder conventional radiographic examination, MSUS can be used to screen the painful shoulder. It is accurate in diagnosing full- and partial-thickness tears of the rotator cuff. Both types of tears can be further characterized by size, location, and extension. Postoperatively, the rotator cuff can also be evaluated for recurrent full-thickness tears. MSUS is the only modality that can visualize and characterize synovial disease, without radiographic contrast, and when necessary, US-guided aspiration and biopsy can be performed. Real-time scanning shows the actual motion of the shoulder and its parts. Multiple attempts can be made to achieve optimal images for accurate documentation. Accessibility to MSUS facilitates the rapid turnaround of patients. US imagers and bone radiologists would do well to use MSUS to help their referring physicians establish a quick and accurate diagnosis of shoulder disorders. This article presents a comprehensive, pictorial review of the technical aspects of shoulder sonography as well as major types of pathology that can be diagnosed with US.

Sonography of the knee, a pictorial review.

The use of ultrasound for evaluation of the knee is increasing. Although it cannot replace magnetic resonance imaging (MRI), which has been the modality of choice in conjunction with plain radiographs, ultrasound does have certain advantages in knee diagnosis. For example, in South Africa the cost of an ultrasound examination is approximately 10% of the cost of an MRI scan. Ultrasound is a very cost-effective alternative for imaging of the knee, providing the indications, advantages, and limitations are understood. Probably the greatest advantage of ultrasound, however, is for the detailed evaluation of the soft tissues within and surrounding the knee. These include ligamentous, tendinous, fibrous, fatty, synovial, and neurovascular structures. These tissues can be assessed for size, continuity, anatomic orientation, and echogenecity; furthermore, they can be readily compared contralaterally. Evaluation of intra-articular elements such as the menisci, cruciate ligaments, and articular cartilage is limited mainly by inaccessibility, which results from the small acoustic windows obtainable in most patients. This liberally illustrated article reviews ultrasound of the knee, including anatomy, ultrasound technique, and pathologic findings.

The association between irregular greater tuberosities and rotator cuff tears: a sonographic study.

OBJECTIVE: Although an association between irregular greater tuberosities and rotator cuff tears has been suggested, no formal studies have been done. This study was designed to investigate the relationship between greater tuberosity irregularities, rotator cuff tears, and age. SUBJECTS AND METHODS: Sonographic examinations of both shoulders of 77 asymptomatic individuals (154 shoulders) between 30 and 80 years old were performed. The rotator cuffs and greater tuberosities were evaluated. Full- and partial-thickness rotator cuff tears were given equal significance. A two-tailed Fisher's exact test, a Student's t test, and logistic regression analysis were used to analyze the data. RESULTS: Sonography showed the greater tuberosity to be irregular in 36 (90%) of 40 shoulders with a rotator cuff tear. The greater tuberosity was irregular in only 12 (11%) of 114 shoulders without a rotator cuff tear. When the greater tuberosity was irregular, sonography showed 36 (75%) of 48 shoulders to have rotator cuff tears. When the greater tuberosity was normal, 102 (96%) of 106 of the rotator cuffs were normal on sonography. Statistical significance was detected (p < .001) for the association of greater tuberosity irregularity and rotator cuff tear. After accounting for age, a statistically significant association was found (p < .001) between rotator cuff status and greater tuberosity status. CONCLUSION: On sonography, greater tuberosity irregularities are reliable indicators in the assessment of shoulders for rotator cuff tears. In addition, we have shown that greater tuberosity irregularities are not simply related to aging.

Ultrasound for the early diagnosis of tibial fracture healing after static interlocked nailing without reaming: histologic correlation using a canine model.

OBJECTIVE: Ultrasound is thought to be clinically useful in evaluating bone formation through its presumed identification of fracture callus. However, documentation of the actual histology of the tissue identified by ultrasound has been lacking. The purpose of this study was to determine the histologic composition of the hyperechoic tissue "seen" by ultrasound. STUDY DESIGN: Unilateral fractures were created in eight canine tibias and then fixed by using locked intramedullary nailing without reaming. The limbs were studied at two, three, four, six, and eight weeks postoperatively with plain radiographs, ultrasound, and ultrasound-directed needle biopsy. RESULTS: The presence of a hyperechoic ultrasound signal was found to have a 100 percent correlation with the presence of hard fracture callus biopsy tissue. In addition, fracture union by ultrasound criteria significantly predated radiographic fracture union (5.6 vs. 7.3 weeks, p = 0.05). CONCLUSIONS: These results support and provide a scientific basis for the clinical use of ultrasound to assess tibial fracture healing following static interlocked nailing without reaming.

Ultrasound for the early diagnosis of tibial fracture healing after static interlocked nailing without reaming: clinical results.

OBJECTIVE: Based on the results of a pilot study indicating the potential value of ultrasound (US) as a diagnostic tool for the early assessment of fracture healing and the related need for secondary operative procedures in patients treated by statically locked intramedullary (IM) nailing without reaming, a protocol was established for a larger scale prospective trial. The purpose of this study was to evaluate the outcome of this follow-up trial. DESIGN/METHODS: All skeletally mature patients admitted to the Henry Ford Hospital (Detroit, Michigan) from January 1993 to August 1994 who had sustained an acute fracture of the tibial shaft and who were treated by statically locked IM nailing, without reaming, were candidates for study. Forty-seven patients with fifty fractures that could be evaluated by US were included. The adopted determinants for fracture healing were complete disappearance of the IM nail on US examination performed at six weeks postoperatively, or progressive disappearance of the nail noted between the initial six-week study and a second nine-week US examination, both in conjunction with periosteal callus formation. Radiographs were obtained to monitor maintenance of reduction and to further evaluate fracture healing. RESULTS: Of thirty-eight fractures with a positive US (thirty-two at six weeks, six at nine weeks), thirty-seven healed uneventfully, a positive predictive value of 97 percent. Radiographic fracture healing was not evident until, on average, nineteen weeks after injury. The single false-positive fracture progressed to nonunion. Of the twelve fractures with negative US studies, ten underwent secondary procedures (nine dynamization, one bone graft), with four progressing to nonunion. Two patients refused secondary surgery; screw failure occurred in both. Otherwise, there were no hardware failures in this series. CONCLUSIONS: The results of this study indicate that US may provide important prognostic information concerning fracture healing after unreamed tibial nailing, upon which subsequent treatment can be based.

US of the ankle: technique, anatomy, and diagnosis of pathologic conditions.

For specific indications, ultrasound (US) is an efficient and inexpensive alternative to magnetic resonance (MR) imaging for evaluation of the ankle. In addition to the tendons and tendon sheaths, other ankle structures demonstrated with US include the anterior joint space, retrocalcaneal bursa, ligaments, and plantar fascia. Ankle US allows detection of tenosynovitis and tendinitis, as well as partial and complete tendon tears. Joint effusions, intraarticular bodies, ganglion cysts, ligamentous tears, and plantar fasciitis can also be diagnosed. As pressure for cost containment continues, demand for US of the ankle may increase given its lower cost compared with that of MR imaging. In most cases, a focused ankle US examination can be performed more rapidly and efficiently than MR imaging. Familiarity with the technique of ankle US, normal US anatomy, and the US appearances of pathologic conditions will establish the role of US as an effective method of imaging the ankle.

Synovial joints: evaluation of intraarticular bodies with US.

PURPOSE: To determine the efficacy of ultrasonography (US) for the detection of intraarticular bodies. MATERIALS AND METHODS: US was performed in 280 patients with symptoms in various appendicular joints by using 5.0-, 7.5-, or 10.0-MHz transducers. Three patients also underwent US with intraarticular saline infusion. US findings were confirmed at surgery in 61 patients. RESULTS: In the 61 patients with surgical correlation, sonograms were positive in 39 and did not show intraarticular bodies in 22. Surgical results confirmed 37 of the positive and all of the negative sonograms. Sensitivity and specificity of US were 100% and 95%, respectively. CONCLUSION: US is an accurate method for identification of intraarticular bodies.

Wooden foreign bodies in soft tissue: detection at US.

PURPOSE: To evaluate the use of ultrasound (US) for detection of wooden foreign bodies implanted in cadaveric specimens. MATERIALS AND METHODS: Wooden foreign bodies were randomly placed in the plantar soft tissues of three cadaver feet by using 5-mm-long incisions. Ten foreign bodies were 2.5 x 1.0 mm (length x diameter); 10 were 5.0 x 1.0 mm. Ten incisions were performed without implantation of foreign bodies. Three musculoskeletal radiologists independently performed US in blinded fashion and recorded the presence of a foreign body. Each used 7.5- and 10-MHz linear-array transducers and was informed of the possible presence of a foreign body. RESULTS: Sensitivity and specificity for detection of 2.5-mm-long foreign bodies were 86.7% and 96.7%, respectively. Sensitivity and specificity for detection of 5.0-mm-long foreign bodies were 93.3% and 96.7%, respectively. Overall sensitivity was 90.0%, with specificity of 96.7%, accuracy of 92.3%, positive predictive value of 98.0%, and negative predictive value of 83.0%. CONCLUSION: US can be used effectively to locate wooden foreign bodies as small as 2.5 mm in length. Given that many foreign bodies are radiographically undetectable, the accuracy and availability of US make it an excellent modality for evaluation of radiolucent foreign bodies.

Osteomyelitis of the diabetic foot: MR imaging-pathologic correlation.

PURPOSE: To evaluate the efficacy of magnetic resonance (MR) imaging for the diagnosis of osteomyelitis in the diabetic foot by using anatomic and histologic studies of the resected tissue as a standard of reference. MATERIALS AND METHODS: Thirteen diabetic patients with high clinical suspicion of osteomyelitis underwent a total of 15 MR examinations before surgery. Correlation was made between MR findings and the histologic features of the resected tissue, which included 57 bones. RESULTS: Maximum signal intensity on the T2-weighted or short inversion time inversion-recovery images of the bones was due to osteomyelitis (prospective sensitivity, 90%; specificity, 71%). Eighteen bones with increased signal intensity showed only edema of the marrow. The range of signal intensity in edema overlapped that in osteomyelitis but was lower. The use of gadopentetate dimeglumine improved delineation of soft-tissue inflammatory masses, but this contrast material was not useful in distinguishing osteomyelitis from edema. CONCLUSION: Marrow edema cannot be reliably distinguished from osteomyelitis with MR imaging. Gadopentetate dimeglumine is of limited use. Some previously published false-positive reports of osteomyelitis were most likely due to edema of the marrow. MR imaging is useful in planning surgery of the infected diabetic foot, as it enables reliable distinction between normal and abnormal areas.

US depiction of partial-thickness tear of the rotator cuff.

PURPOSE: To test previously defined ultrasound (US) criteria for identification of partial-thickness tears of the rotator cuff. MATERIALS AND METHODS: Before shoulder arthroscopy, 52 patients with shoulder pain for more than 3 months were examined with a 7.5-MHz commercially available linear-array transducer and a standardized study protocol. The criteria used to detect partial-thickness tears were (a) a mixed hyper- and hypoechoic focus in the crucial zone of the supraspinatus tendon and (b) a hypoechoic lesion visualized in two orthogonal imaging planes with either articular or bursal extension. RESULTS: The US findings were reported as partial-thickness tears in 17 shoulders, of which three were false-positive findings. There was one false-negative finding. The sensitivity of US in depiction of partial-thickness tears was 93%, and specificity was 94%. The positive predictive value was 82%, and the negative predictive value was 98%. CONCLUSION: US can depict most partial-thickness tears with use of the criteria described.

Distinguishing benign from malignant euadrenal masses.

STUDY OBJECTIVE: To determine the efficacy of 131I-6-beta-iodomethylnorcholesterol (NP-59) adrenal scintigraphy in distinguishing benign from malignant euadrenal masses. DESIGN: Case series of patients with incidentally discovered unilateral, euadrenal masses. SETTING: Referral-based nuclear medicine clinics at university and affiliated Veterans Administration medical centers. PATIENTS: Consecutive sample of 119 euadrenal patients with unilateral adrenal masses discovered on computed tomographic (CT) scans for reasons other than suspected adrenal disease. INTERVENTIONS: Adrenal scintiscans done using 1 mCi of NP-59 intravenously, and gamma camera imaging 5 to 7 days later. MEASUREMENTS AND MAIN RESULTS: Mean lesion diameter was 3.3 +/- 1.9 cm (SD) (95% CI: 2.9 to 3.6 cm). In 76 patients, NP-59 uptake lateralized to the abnormal adrenal seen on CT scans (concordant imaging), and in all of these patients, a diagnosis of adenoma was made by needle-aspiration biopsy, adrenalectomy, or extended follow-up with repeat CT scans that were unchanged at 6 months or later. Twenty-six patients had absent or markedly reduced NP-59 uptake in the glands identified as abnormal on CT scans (discordant imaging). These adrenal masses proved to be metastatic malignancies in 19 patients, primary adrenal neoplasms other than adenoma in 4, and adrenal cysts in 3. Bilateral, symmetric accumulation of NP-59 was seen in 17 patients, in whom the adrenal masses were shown to be metastatic malignancies in 2, and adenomas in 6 (the lesions in these cases being 2 cm or less in diameter), and lesions not truly involving the adrenal in the rest (periadrenal metastases in 4 and pseudoadrenal masses in 5). Sensitivity was 76% (26 of 34 patients; CI, 58% to 88%); specificity, 100% (85 of 85 patients; CI, 95% to 100%), and accuracy, 93% (111 of 119 patients: CI, 88% to 98%). CONCLUSIONS: Functional NP-59 scintigraphy can be used to accurately and noninvasively characterize many euadrenal masses; concordance of CT and NP-59 scans can be used to exclude the presence of a malignancy or other space-occupying adrenal lesion.

Functional and scintigraphic evaluation of the silent adrenal mass.

Seven patients with unilateral and one patient with bilateral and asymmetric (R greater than L) incidentally discovered adrenal mass abnormalities depicted by computed tomography (CT) were studied by 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scintigraphy. There was marked lateralization of NP-59 uptake to the side of the mass lesion in the seven patients with unilateral masses and prominent asymmetric, (R greater than L) bilateral uptake in the patient with bilateral masses despite the fact that there were no obvious abnormalities of adrenocortical or adrenomedullary function as determined from peripheral blood and 24-hr urinary hormone measurements. Simultaneous bilateral adrenal vein catheterization (AVC) was employed to measure the levels of hormone effluent from the adrenal cortex and medulla and in all instances the cortisol concentrations were greatest from the side of the mass lesion in those patients with unilateral masses and from the larger of the two adrenals in the patient with bilateral adrenal masses. Thus, there was congruence between the anatomic (CT) and functional (NP-59 scintigraphy and AVC) investigations that depicted asymmetry of the adrenal glands which were not associated with abnormalities of overall adrenal function or hypothalamic-pituitary-adrenal axis integrity.

Treatment of established prosthetic vascular graft infection with antibiotics preferentially concentrated in leukocytes.

The efficacy of treating established vascular graft infections with rifampin and clindamycin (preferentially concentrated in leukocytes) and cefazolin (not concentrated in leukocytes) was studied in a canine model. Infrarenal aortic, 6 mm by 6 cm knitted Dacron double velour grafts were implanted and infected with 10(8) colony-forming units (CFU) of coagulase-positive Staphyloccus aureus organisms injected intravenously immediately after graft placement. Antibiotic therapy was instituted at 3 months postimplantation. Three groups were studied: (I) untreated controls (n = 3); (II) therapy with intravenous cefazolin 15 mg/kg/8 hr for 28 days (n = 7); and (III) combined therapy with intravenous rifampin 13 mg/kg/24 hr and intravenous clindamycin 13 mg/kg/8 hr for 28 days (n = 7). Grafts were removed for quantitative bacteriologic studies after the 28-day course of therapy. Two group I control grafts remained patent with 6.4 X 10(6) and 8.1 X 10(3) CFU S. aureus/gm of graft. The third control graft was thrombosed. Two group II animals demonstrated 1.6 X 10(7) and 2.3 X 10(5) CFU S. aureus organisms/gram of graft, respectively; the remaining five group II grafts were free of organisms. All group III grafts were sterile--a significant difference (p less than 0.05) from group I grafts. In this experimental model, established prosthetic graft infections were eradicated by intensive treatment with antibiotics preferentially concentrated in leukocytes.

Sonographic detection of interstitial pregnancy.

Interstitial pregnancy is a rare form of ectopic pregnancy that carries a higher morbidity and mortality than other tubal pregnancies. The sonographic findings in 11 cases of proven interstitial pregnancy were reviewed and compared with 12 cases published thus far. An ectopic pregnancy was diagnosed in all cases, and an interstitial location was suspected in five cases preoperatively. An eccentrically located gestational sac surrounded by an asymmetric myometrial mantle and a separate empty uterine cavity with endometrial echoes were the most common findings in our cases. When an interstitial pregnancy is suspected by sonography, confirmation by laparoscopy is recommended.