Environmental fate assessment of two synthetic polycarboxylate polymers.

In order to estimate the proportion which may enter the aquatic environment and characterize exposure potential, the environmental fate properties of two polycarboxylate polymers in activated sludge were determined. The polycarboxylates studied were a polymer emulsion (PE), a high-molecular-weight polymer (MW 50,000-60,000), and a resin polymer (RP), a low-molecular-weight polymer (MW 4500 to 9000). Both polymers exhibited a high degree of sorption to sludge solids in a series of sorption/ desorption studies, indicating a high potential for removal during wastewater treatment. In isotherm tests, the adsorption coefficient, Koc, was 1060 and 2730 for the RP and the PE, respectively. The biodegradation of the two polymers was measured under aerobic conditions in a 60-day semicontinuous activated sludge test and in a 60-day modified Sturm test using 14C-labeled compounds. In both studies, polymers accumulated in sludge solids over time and there was no evidence of significant biodegradation, although small amounts of radiolabeled CO2 were produced, suggesting the potential for biodegradation. Testing confirmed that the lack of biodegradation was not due to inhibition of microbial respiration by the polymers. High removals of PE and RP during wastewater treatment were confirmed in a field study at a facility receiving polymer inputs from households and manufacturing plants.

Femur fractures in infants: a new therapeutic approach.

Fourteen patients with 16 femur fractures sustained between birth and 18 months of age were treated with a Pavlik harness rather than traditional casting methods. All of the fractures went on to stable union within 5 weeks. Eleven fractures have been followed-up for > 12 months, with a range of 12-30 months, and a mean of 20.1 months. All of the fractures healed in good alignment, with leg-length discrepancies < 1 cm. There have been no adverse results or complications as a result of treatment with the Pavlik harness to treat femur fractures, including fractures of the proximal and middle thirds of the femur; nonambulatory infants; < 4 months old at the start of treatment or small size in selected infants up to 6 months old; and shortening of < 2 cm. Advantages of the use of the Pavlik harness include ease of application without general anesthesia, minimal hospitalization, ease of reduction, ability to adjust the harness (and therefore the fracture alignment) if the reduction is lost, minimal cost, and ease of nursing, bonding with, and changing diapers on the infant.

Arthroscopic Bankart procedure: two- to five-year followup with clinical correlation to severity of glenoid labral lesion.

We report our results using the arthroscopic Bankart technique described by Morgan (transglenoid suture) on 60 consecutive patients with anterior instability. All had detachment of the glenoid labrum at surgery. Forty-seven patients were available for final followup, which ranged from 2 to 5 years. Of these patients, 18 had experienced recurrent dislocation and 3 had experienced episodes of subluxation after surgery, for an overall failure rate of 42%. Partway into the study, we began to correlate severity of glenoid labral lesion with outcome. We classified the labral lesion in 37 patients using stringent criteria at the time of surgery. Followup among these patients averaged 37 months. Of 22 cases of simple detachment of the labrum with no other significant lesion (Type II labrum), there was one failure (4.5%). Of the 15 cases with significant or complete degeneration of the glenoid labrum-inferior glenohumeral ligament complex (Types IV or V labra), 13 failed (87%). Of the patients without recurrent instability, loss of external rotation averaged 1.5 degrees, strength was 5+/5+ in abduction and external rotation. Average postoperative function was 94% of preinjury levels subjectively, and most patients were able to return to previous activities, including throwing and other overhead sports. Our findings indicate that rates of redislocation after this arthroscopic Bankart procedure correlate directly with the degree of glenoid labrum-inferior glenohumeral ligament complex lesion.

Detection and staging of chondromalacia patellae: relative efficacies of conventional MR imaging, MR arthrography, and CT arthrography.

OBJECTIVE: Chondromalacia patellae is a condition characterized by softening, fraying, and ulceration of patellar articular cartilage. We compare the sensitivity, specificity, and accuracy of conventional MR imaging, MR arthrography, and CT arthrography in detecting and staging this abnormality. SUBJECTS AND METHODS: Twenty-seven patients with pain in the anterior part of the knee were prospectively examined with MR imaging, including T1-weighted (650/16), proton density-weighted (2000/20), T2-weighted (2000/80), and spoiled two-dimensional gradient-recalled acquisition in the steady state (SPGR/)/35 degrees (51/10) with fat saturation pulse sequences. All were also examined with T1-weighted MR imaging after intraarticular injection of dilute gadopentetate dimeglumine and with double-contrast CT arthrography. Each imaging technique was evaluated independently by two observers, who reached a consensus interpretation. The signal characteristics of cartilage on MR images and contour abnormalities noted with all imaging techniques were evaluated and graded according to a modification of the classification of Shahriaree. Twenty-six of the 54 facets examined had chondromalacia shown by arthroscopy, which was used as the standard of reference. The sensitivity, specificity, and accuracy of each imaging technique in the diagnosis of each stage of chondromalacia patellae were determined and compared by using the McNemar two-tailed analysis. RESULTS: Arthroscopy showed that 28 facets were normal. Grade 1 chondromalacia patellae was diagnosed only with MR and CT arthrography in two (29%) of seven facets. Intermediate (grade 2 or 3) chondromalacia patellae was detected in two (13%) of 15 facets with T1-weighted and SPGR MR imaging, in three (20%) of 15 facets with proton density-weighted MR imaging, in seven (47%) of 15 facets with T2-weighted MR imaging, in 11 (73%) of 15 facets with CT arthrography, and in 12 (80%) of 15 facets with MR arthrography. Grade 4 was detected in three (75%) of four facets with T1-, proton density-, and T2-weighted MR imaging, two (50%) of four facets with SPGR MR imaging, and four (100%) of four facets with MR and CT arthrography. Thus, all imaging techniques were insensitive to grade 1 lesions and highly sensitive to grade 4 lesions, so that no significant difference among the techniques could be shown. CONCLUSION: All imaging techniques studied had high specificity and accuracy in the detection and grading of chondromalacia patella; however, both MR arthrography and CT arthrography were more sensitive than T1-weighted, proton density-weighted, and SPGR with fat saturation MR imaging for showing intermediate grades of chondromalacia patellae. Although the arthrographic techniques were not significantly better than T2-weighted imaging, the number of false-positive diagnoses was greatest with T2-weighted MR imaging.

Magnetic resonance imaging of the glenoid labrum in anterior shoulder instability.

Detachment of the anterior inferior labrum and inferior glenohumeral ligament complex from the glenoid is a common lesion encountered in anterior shoulder instability while other types of labral lesions are associated with symptoms that mimic instability. Accurate delineation of labral lesion is, therefore, key in managing shoulder problems. In a prospective double-blinded fashion, we compared the magnetic resonance imaging findings with those noted at surgery in 33 patients with possible anterior shoulder instability. Of 28 surgically confirmed labral lesions, 21 were detected by imaging. Sensitivity was 75%, specificity 100%, while positive and negative predictive values were 100% and 41%, respectively. Overall accuracy was 79%. Based on a literature review and our clinical experience, we developed a classification of glenoid labra according to the type and severity of the lesions. Method of treatment correlated with clinical outcome, using this system, to a statistically significant level. Unfortunately, this system enabled accurate classification with magnetic resonance imaging in only 7 of 33 (21%) labra, with the precision necessary to affect surgical planning in our series. We conclude that magnetic resonance imaging is not useful in the surgical planning for most patients with obvious anterior shoulder instability.

Chronic ankle instability: evaluation with MR arthrography, MR imaging, and stress radiography.

PURPOSE: To compare the efficacy of conventional magnetic resonance (MR) imaging, MR arthrography, and stress radiography in the detection of lateral collateral ligament abnormalities in patients with chronic ankle instability. MATERIALS AND METHODS: Seventeen patients with chronic lateral ankle instability underwent stress radiography, MR imaging, and MR arthrography after intraarticular injection of gadopentetate dimeglumine. Imaging findings were correlated with surgical findings. RESULTS: The anterior talofibular (ATF) ligament was torn in 14 patients, and the calcaneofibular (CF) ligament was torn in 10. MR arthrography was more accurate and sensitive in the detection of ATF tears than was MR imaging or stress radiography (P < or = .05). Associated injuries were detected with both MR imaging and MR arthrography. CONCLUSION: MR arthrography is a sensitive technique for detecting and staging tears of the lateral collateral ligaments.

Arthroscopic versus open Bankart procedures: a comparison of early morbidity and complications.

Morgan recently reported excellent results by arthroscopically suturing detached labra to the glenoid via drill holes in anterior shoulder dislocators. We attempted to quantitatively compare the operative time, and perioperative morbidity employing this technique to these same parameters using the open Bankart procedure. We retrospectively reviewed the records of consecutive patients undergoing either of these procedures at our institution over the past 2 years. Only those cases wherein the labra were reattached to the glenoid via drill holes were considered. There were 20 patients in the arthroscopic and 18 in the open Bankart groups. Using the arthroscopic method, there was a 1.8-fold decrease in operative time, a 10-fold decrease in blood loss, and a 2.5-fold decrease in postoperative narcotic use compared with the open procedure (p < 0.001). Postoperative fevers were similarly reduced. Hospital stay averaged 3.1 days with the open procedure compared with 1.1 days with the arthroscopic method (p < 0.001). Most arthroscopic Bankarts are now performed on a same-day basis. Time lost from work was 25.5 and 15.3 days for the open and arthroscopic procedures, respectively (p < 0.001). There were three complications among the patients treated with the open technique compared with none in the arthroscopic group. Thus, we conclude that the arthroscopic Bankart procedure offers significant improvements in operative time, perioperative morbidity, and complications compared with the open technique for patients with anterior shoulder instability.

An irreducible fracture-dislocation of a lesser toe: a case report.

Lesser toe dislocations are unusual injuries that are amenable to closed reduction in most cases. We present a case of an isolated lesser toe fracture-dislocation that required an open reduction due to soft tissue interposition.