Faculty Bibliography

Objectives- The purpose of this study was to determine the reliability in the analysis of images acquired using a dedicated 3-dimensional (3D) ultrasound transducer and conventional 2-dimensional (2D) images in the detection and characterization of supraspinatus tendon tears. Methods- Images of the supraspinatus tendon in 42 patients who had undergone 2D and 3D sonography were classified by two readers independently as no tear, full-thickness tear, or partial-thickness tear. When present, the tear size and location were recorded. Inter- and intra-rater reliability for the two data sets were calculated. Results- There was substantial agreement between the two readers in the classification of supraspinatus tendon tears on 2D images (kappa = 0.79) but only moderate agreement on 3D images (kappa = 0.48). There was moderate to substantial agreement in the classification of tears between the 2D and 3D images for both readers (reader 1, kappa = 0.64; reader 2, kappa= 0.54). The most common cause of a discordant result was the interpretation of a small hypoechoic region at the footprint as a partial tear on 3D images, compared to a normal appearance on 2D images. Conclusions- Use of a dedicated 3D ultrasound transducer has poorer inter- and intra-rater reliability for the assessment of supraspinatus tendon tears compared to 2D sonography because of the interpretation of small partial-thickness tears at the footprint on 3D images, a common region affected by anisotropy.

BACKGROUND: A rotator cuff registry was established to prospectively evaluate the effectiveness of all-arthroscopic repairs. This study reports those results at 5 years. MATERIALS AND METHODS: The study enrolled 193 patients who underwent all-arthroscopic rotator cuff repairs. Patients were evaluated preoperatively and at 1, 2, and 5 years postoperatively. Outcome measurements included the American Shoulder and Elbow Surgeons (ASES) score, range of motion, manual muscle testing, and ultrasonography. RESULTS: At 5-years, 106 patients completed follow-up, representing 55% of the patients originally enrolled but 77% of those who returned for evaluation at 1 year. ASES scores improved from 52.6 +/- 23.2 preoperatively to 92.6 +/- 14.8 at 5 years (P < .001). Paired analyses showed no differences between the ASES scores at 2 and 5 years, but the scores improved from 1 to 5 years (P = .002). Between years 2 and 5, passive forward elevation decreased from 173 degrees +/- 10.3 degrees to 168.6 degrees +/- 16.8 degrees (P = .02) and external rotation decreased from 73.6 degrees +/- 21.3 degrees to 67.8 degrees +/- 19.6 degrees (P = .04). Patients improved a full motor grade in forward elevation and external rotation and this remained stable over time. The healing rates for all patients were 64.3% at 1 year, 75.4% at 2 years, and 81.2% at 5 years. Paired analyses showed increased healing rates from 1 to 5 years (P = .001) and from 2 to 5 years (P = .05). DISCUSSION: The midrange results of all-arthroscopic rotator cuff repairs are good, and functional results remain constant over 5 years. The ultrasound healing rates continued to increase with time; however, the mechanism and the clinical significance of this are uncertain at this time.

BACKGROUND: A rotator cuff registry was established to prospectively evaluate the effectiveness of all-arthroscopic repairs. The purpose of this study is to report prognostic factors for successful clinical and radiographic outcomes at 5 years. METHODS: One-hundred ninety-three patients underwent all-arthroscopic rotator cuff repairs. Pre- and intraoperative data were compared to the American Shoulder and Elbow Surgeon (ASES) score, range of motion, muscle strength, and ultrasound results at 5 years using univariate, and multivariate analyses. RESULTS: At 5 years, 106 patients completed follow-up. There were no pre- or intraoperative variables that were predictive of an ASES score >90. Factors predictive of a radiographic defect were larger size of the lesion (OR 1.72, 95% CI 1.04-2.85, P = .03), multiple tendon involvement (OR 5.56, 95% CI 1.23-25.22, P = .02), older age (OR 1.15, 95% CI 1.04-1.28, P = .01), concomitant biceps (OR 16.16, 95% CI 3.01-86.65, P = .001), and acromioclavicular joint procedures (OR 6.70, 95% CI 1.46-30.73, P = .01). Radiographic healing did not correspond to clinical outcomes. Resolution of a radiographic defect was seen in 14 patients. Younger age (OR 0.84, 95% CI 0.74-0.95, P = .004) and single-tendon tears (OR 7.59, 95% CI 1.71-84.45, P = .04) were predictive. DISCUSSION: Larger tears in older patients who undergo concomitant procedures are predictive of radiographic defects at 5 years; however, radiographic healing did not correspond to clinical results. Younger patients with single tendon tears are more likely to undergo spontaneous resolution of a radiographic defect. This information can be useful in counseling patients regarding the mid-term results of this procedure.

OBJECTIVES: To characterize the distribution of vascularity of the postoperative rotator cuff tendon using a maximum intensity projection technique after contrast-enhanced sonography. METHODS: We retrospectively evaluated image data on 23 patients (11 male and 12 female) with intact rotator cuff repairs who had previously undergone contrast-enhanced sonography of their shoulders using lipid microspheres before and after a standardized exercise protocol. The patients were on average 3 months out from their surgery. Using offline image analysis software, a maximum intensity projection image was obtained for each patient, reflecting the regional vascular distribution within the repair and adjacent soft tissue. Subjective analysis was performed in 4 regions of interest: peribursal, articular medial, articular lateral, and suture anchor, independently by 2 musculoskeletal radiologists using a semiquantitative scale ranging from 0 to 4 for each region (0, no enhancement; 1, 1%-25% enhancement; 2, 26%-50%; 3, 51%-75%; and 4, 76%-100%). A combined vascularity score (0-8) was produced for each region and formed the basis for the subjective analysis. RESULTS: Using a Mann-Whitney nonparametric test, the data showed significantly higher regional enhancement in the peribursal and suture anchor regions compared to the tendon (P < .001). Exercise resulted in a statistically significant increase in the extent of enhancement in all regions (P < .002). Inter-rater reliability analysis using a weighted kappa statistic showed strong agreement (0.63-0.64) for the suture anchor site and moderate agreement for the others (peribursal, 0.35-0.39; articular medial, 0.45-0.55; and articular lateral 0.32-0.33). CONCLUSIONS: The maximum intensity projection technique after contrast-enhanced sonography provides a topographic map of rotator cuff vascularity; the latter has been implicated as an important factor in promoting bone-tendon healing. Approximately 3 months after rotator cuff repair, the suture anchor and peribursal regions showed the most robust vascularity. Maximum intensity projection imaging further establishes that there is a global increase in vascular response at the repair site after exercise.

OBJECTIVES: The purpose of this study was to investigate whether routine clinical sonographic evaluation of femoral trochlear cartilage can identify abnormalities in patients with knee pain. METHODS: Short-axis sonograms of the femoral trochlear cartilage were obtained from 20 symptomatic knees in 20 consecutive patients (16 women and 4 men; mean age, 54 years; range, 35-75 years) and 20 knees in 10 asymptomatic control participants (7 women and 3 men; mean age, 52 years; range, 31-74 years). Articular cartilage thickness was measured at 3 locations in each knee, and thickness at each site was compared between patients and controls. Subsequently, images from patients and controls were randomly assorted and evaluated by 3 blinded musculoskeletal radiologists, who independently evaluated the femoral trochlear cartilage in each sonogram for cartilage clarity, grade, and presence or absence of cartilage calcifications, osteophytes, and subchondral bony irregularity. The radiologists were instructed to rate the most severe lesion in each evaluated region (medial trochlea, trochlear notch, and lateral trochlea). Cartilage clarity was defined as how well the cartilage borders could be distinguished from the overlying intra-articular soft tissues, and grade was defined as the severity of focal cartilaginous lesions. RESULTS: Using the Student t test, there was no significant difference (P > .05) between cartilage thickness in patients and controls for any location measured. However, using repeated measures analysis of variance, there were significant differences (P = .02) for both decreased cartilage clarity (df = 1/28; F = 5.76) and increased grade (df = 1/28; F = 5.77) in patients. There was also a nonsignificant (P > .05) trend toward more frequent calcifications, osteophytes, and bony irregularity in patients. CONCLUSIONS: Routine clinical sonography can identify femoral trochlear cartilage abnormalities in patients with knee pain and therefore can be a useful adjunct to other imaging tests for identifying arthritic changes in the knee.

The development of iatrogenic nerve lesions during and following limb lengthening procedures present a challenge to orthopedic surgeons. Early treatment of nerve damage is critical in salvaging full function of the nerve. Precise location of damage, however, must be determined in order to appropriately administer treatment. We report a patient with a short humerus caused by a growth arrest undergoing a 7-cm lengthening who developed a neurapraxic injury of the radial nerve. Nerve compromise was noted 1 month into the lengthening program. Nerve conduction studies and electromyography could not be used to determine the precise site of injury. Likewise, magnetic resonance imaging and computed tomography were contraindicated and inconclusive, respectively, due to the presence of a metallic external fixation device. High-resolution ultrasonography (US) findings, however, correlated with our clinical examination of the patient's radial nerve function and permitted identification of the precise site of nerve involvement. Treatment was administered by removing a causative half-pin. Several days following treatment, nerve function returned to normal. There are a limited number of articles in the literature regarding nerve injuries associated with limb lengthening and their corrective treatments. The outcome of this case underscores the usefulness of US over various other diagnostic techniques under certain circumstances.

Electromyography (EMG) of the shoulder girdle is commonly performed; however, EMG spectral properties of shoulder muscles have not been clearly defined. The purpose of this study was to determine the maximum power frequency, Nyquist rate, and minimum sampling rate for indwelling and surface EMG of the normal shoulder girdle musculature. EMG signals were recorded using indwelling electrodes for the rotator cuff muscles and surface electrodes for ten additional shoulder muscles in ten healthy volunteers. A fast Fourier transform was performed on the raw EMG signal collected during maximal isometric contractions to derive the power spectral density. The 95% power frequency was calculated during the ramp and plateau subphase of each contraction. Data were analyzed with analysis of variance (ANOVA) and paired t tests. Indwelling EMG signals had more than twice the frequency content of surface EMG signals (p < .001). Mean 95% power frequencies ranged from 495 to 560 Hz for indwelling electrodes and from 152 to 260 Hz for surface electrodes. Significant differences in the mean 95% power frequencies existed among muscles monitored with surface electrodes (p = .002), but not among muscles monitored with indwelling electrodes (p = .961). No significant differences in the 95% power frequencies existed among contraction subphases for any of the muscle-electrode combinations. Maximum Nyquist rate was 893 Hz for surface electrodes and 1,764 Hz for indwelling electrodes. Our results suggest that when recording EMG of shoulder muscles, the minimum sampling frequency is 1,340 Hz for surface electrodes and 2,650 Hz for indwelling electrodes. The minimum sampling recommendations are higher than the 1,000 Hz reported in many studies involving EMG of the shoulder.

Leiomyomas arising outside of the uterus and gastrointestinal tract are uncommon, though these benign soft tissue neoplasms have been reported in the lower extremity and foot. To our knowledge, the sonographic appearance of a lower extremity leiomyoma has not been described in the literature. This report involves a case of leiomyoma of the foot and its sonographic imaging features. MR correlative imaging and histopathology are also provided.

Spine surgery is associated with a significant risk of postoperative pulmonary embolism (PE) and/or deep vein thrombosis (DVT). The goal of this study was to determine which symptoms and risk factors were associated with spiral CT scans positive for PE and/or DVT in the postoperative spine surgery patient. We conducted a retrospective review of all spine patients who underwent a postoperative CT to rule out PE during the period of March 2004-February 2006. The type of surgical procedure, risk factors, symptoms prompting scan ordering, anticoagulation, and treatment were recorded. Logistic regression models were used to determine significant predictors of a positive CT in this patient population. Of the 3,331 patients that had spine surgery during the study period, 130 (3.9%) had a spiral CT scan to rule out PE and/or proximal DVT. Thirty-three of the 130 (25.4%) CT scans were positive for PE only, five (3.8%) for PE and DVT, and three (2.3%) for DVT only. Only 24.5% (32) patients had risk factors for thromboembolic disease, and of these, a history of PE and/or DVT was the only significant risk factor for a positive scan (p = 0.03). No presenting symptoms or demographic variables were noted to have a significant association with PE and/or DVT. The type of surgical procedure (i.e., anterior, posterior, and percutaneous) was not associated with an increased risk for PE and/or DVT. Patients who are undergoing spine surgery with a history of thromboembolic disease should be carefully monitored postoperatively and may benefit from more aggressive prophylaxis.