Faculty Bibliography

BACKGROUND: Chronic ruptures of the distal biceps are often complicated by tendon retraction and fibrosis, precluding primary repair. Reconstruction with allograft augmentation has been proposed as an alternative for cases not amenable to primary repair. PURPOSE: To investigate the clinical outcomes of late distal biceps reconstruction using allograft tissue. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 20 patients who underwent distal biceps reconstruction with allograft tissue between May 2007 and May 2012 were identified. Charts were retrospectively reviewed for postoperative complications, gross flexion and supination strength, and range of motion. Subjective functional outcomes were assessed prospectively with the Mayo Elbow Performance Score (MEPS) and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. RESULTS: Eighteen patients with adequate follow-up were included in the study. All had undergone late distal biceps reconstruction with allografts (Achilles [n = 15], semitendinosus [n = 1], gracilis [n = 1], or anterior tibialis [n = 1]) for symptomatic chronic ruptures of the distal biceps. At a mean office follow-up of 9.3 months (range, 4-14 months), all patients had full range of motion and mean gross strength of 4.7 of 5 (range, 4-5) in flexion and supination. After a mean out-of-office follow-up at 21 months (range, 7-68.8 months), the mean DASH score was 7.5 +/- 17.9, and the mean MEPS increased from 43.1 preoperatively to 94.2 postoperatively (P < .001). The only complication observed was transient posterior interosseous nerve palsy in 2 patients. Additionally, all but 1 patient reported a cosmetic deformity. However, all patients found it acceptable. CONCLUSION: Late reconstruction for chronic ruptures of the distal biceps using allograft tissue is a safe and effective solution for symptomatic patients with functional demands in forearm supination and elbow flexion. While there are several graft options, the literature supports good results with Achilles tendon allografts. Further studies are needed to evaluate the clinical outcomes of other allograft options.

OBJECT: Our objective was to use 7 T MRI to compare cartilage morphology (thickness) and collagen composition (T2 values) in cartilage repair patients and healthy controls. MATERIALS AND METHODS: We scanned the knees of 11 cartilage repair patients and 11 controls on a 7 T MRI scanner using a high-resolution, gradient-echo sequence to measure cartilage thickness and a multi-echo spin-echo sequence to measure cartilage T2 values. We used two-tailed t tests to compare cartilage thickness and T2 values in: repair tissue (RT) versus adjacent cartilage (AC); RT versus healthy control cartilage (HC); AC versus HC. RESULTS: Mean thickness in RT, AC, HC were: 2.2 +/- 1.4, 3.6 +/- 1.1, 3.3 +/- 0.7 mm. Differences in thickness between RT-AC (p = 0.01) and RT-HC (p = 0.02) were significant, but not AC-HC (p = 0.45). Mean T2 values in RT, AC, HC were: 51.6 +/- 7.6, 40.0 +/- 4.7, 45.9 +/- 3.7 ms. Differences in T2 values between RT-AC (p = 0.0005), RT-HC (p = 0.04), and AC-HC (p = 0.004) were significant. CONCLUSION: 7 T MRI allows detection of differences in morphology and collagen architecture in: (1) cartilage repair tissue compared to adjacent cartilage and (2) cartilage repair tissue compared to cartilage from healthy controls. Although cartilage adjacent to repair tissue may be normal in thickness, it can demonstrate altered collagen composition.

OBJECTIVE. The purpose of this study was to define and correlate the appearance of the rotator cable on MRI with arthroscopy, band-saw cadaveric sections, and histology. MATERIALS AND METHODS. Two cadaveric shoulders underwent 3-T MRI, band-sawing, and histologic evaluation. Three readers evaluated the MRI for the presence of the cable, and the same readers and a pathologist reviewed the macroscopic and microscopic specimens for a structure that corresponded to the cable. Cadaver 1 underwent arthroscopic evaluation to evaluate for the presence of a cable. Seventy consecutive shoulders that underwent 1.5- or 3-T MRI were also reviewed for the presence of the cable and evaluation of its characteristics (location, thickness, and width). RESULTS. A linear band of hypointense signal intensity was found along the undersur-face of the supraspinatus and infraspinatus tendons on both cadaveric MR images, which correlated to a linear band of tissue in the same location on macroscopic and microscopic evaluation and linear thickening along the cuff articular surface on arthroscopy consistent with the cable. The cable was seen in 74.3% of the MRI studies in both sagittal and coronal planes with a mean (+/- SD) distance of the cable from the medial margin of the enthesis of 1.33 +/- 0.27 cm, a mean width of the cable of 1.24 +/- 0.31 cm, and a mean thickness of 0.19 +/- 0.05 cm. CONCLUSION. The rotator cable is a structure that can be consistently seen on gross anatomic and histologic analysis, arthroscopy, and MRI in the intact rotator cuff. Familiarity with the typical location and morphology of the cable may allow easier characterization of disease that can involve the cable, such as rotator cuff tears.

BACKGROUND: Injection to the acromioclavicular (AC) joint can be both diagnostic and therapeutic. PURPOSE: The purpose of this study was to evaluate the accuracy of in vivo AC joint injections. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirty patients with pain localized to the AC joint were injected with 1 mL of 1% lidocaine and 0.5 mL of radiographic contrast material (Isovue). Radiographs of the AC joint were taken after the injection. Each radiograph was reviewed by a musculoskeletal radiologist and graded as intra-articular, extra-articular, or partially intra-articular. RESULTS: Of the 30 injections performed, 13 (43.3%) were intra-articular, 7 (23.3%) were partially articular, and 10 (33.3%) were extra-articular. When the intra-articular and the partially articular groups were combined, 20 patients (66.7%) had some contrast dye in the AC joint. CONCLUSION: This study demonstrates that despite the relatively superficial location of the AC joint, the clinical accuracy of AC joint injections remains relatively low.

BACKGROUND: Intra-articular glenohumeral (GH) injections are important for diagnostic and therapeutic purposes. It has been suggested that ultrasound guided injections are more accurate than blind or freehand injections. This study assessed the accuracy of ultrasound-guided GH injections compared with freehand injections in fresh cadavers. METHODS: The study used 80 shoulder specimens from fresh cadavers. Ultrasound guidance was used to inject radiopaque contrast in 40 shoulders, and freehand technique was used in the remaining 40. All injections were performed by 2 surgeons (A and B) through a posterior approach. After the injections, radiographs were obtained of the specimens to assess the accuracy of the injections. RESULTS: Sixty-six of 80 (82.5%) injections were accurately administered into the GH joint. Ultrasound-guided injections were accurate in 37 of 40 specimens (92.5%) compared with freehand injections, which were accurate in only 29 of 40 specimens (72.5%; P = .02). Both surgeons independently had higher accuracy using ultrasound-guidance compared with the freehand technique (surgeon A: 90% vs 65%, P = 0.058; surgeon B: 95% vs 80%, P = 0.15). The average time for injections was 52 seconds by the freehand technique and 166 seconds using ultrasound guidance (P < 0.001). CONCLUSIONS: The data from this cadaveric study suggest that ultrasound-guided injections are more accurate at reaching the GH joint than freehand injections. The ultrasound-guided injections took substantially longer to administer. Once familiar with the technique, surgeons can expect improved accuracy and efficacy of GH joint injections using ultrasound guidance in the clinical setting.

OBJECTIVE: The purpose of this study is to assess the accuracy of MRI quantification of glenoid bone loss and to compare the diagnostic accuracy of MRI to CT in the measurement of glenoid bone loss. MATERIALS AND METHODS: MRI, CT, and 3D CT examinations of 18 cadaveric glenoids were obtained after the creation of defects along the anterior and anteroinferior glenoid. The defects were measured by three readers separately and blindly using the circle method. These measurements were compared with measurements made on digital photographic images of the cadaveric glenoids. Paired sample Student t tests were used to compare the imaging modalities. Concordance correlation coefficients were also calculated to measure interobserver agreement. RESULTS: Our data show that MRI could be used to accurately measure glenoid bone loss with a small margin of error (mean, 3.44%; range, 2.06-5.94%) in estimated percentage loss. MRI accuracy was similar to that of both CT and 3D CT for glenoid loss measurements in our study for the readers familiar with the circle method, with 1.3% as the maximum expected difference in accuracy of the percentage bone loss between the different modalities (95% confidence). CONCLUSION: Glenoid bone loss can be accurately measured on MRI using the circle method. The MRI quantification of glenoid bone loss compares favorably to measurements obtained using 3D CT and CT. The accuracy of the measurements correlates with the level of training, and a learning curve is expected before mastering this technique.

MRI has been shown to be both sensitive and specific in the diagnosis of partial thickness and full-thickness tears of the rotator cuff. Recognizing the pattern of a rotator cuff tear before surgery also provides useful information to the referring clinician as it can help in the selection of the type of surgery and lead to a better anatomic and biomechanical restoration of the cuff tendons. There is relative paucity of published reports exploring the performance of MRI in the recognition and classification of rotator cuff tears based on their morphological pattern. The purpose of this exhibit is: 1) to describe the geometric patterns of rotator cuff tears, 2) to illustrate the MR imaging appearance of the different patterns of rotator cuff tearing, 3) to describe the clinical significance of the different patterns in terms of treatment selection and outcome prediction. Characterization of the most common rotator cuff tear patterns will be presented including: crescent-shaped, U-shaped, L-shaped, and massive cuff tears. This will be followed by a guide that can be used to recognize these patterns on MRI utilizing the location as well as the size of the transverse and longitudinal components of the tear on surgically proven cases. Finally, a review of the different types of repairs currently available for each tear pattern will be presented including end-to-bone repair and margin convergence techniques as well as the expected postsurgical outcomes

The rotator cable, an extension of the coracohumeral ligament, is a fibrous band-like structure that courses along the undersurface of the supraspinatus and infraspinatus tendons perpendicular to their tendon fibers. Originally described in the orthopaedic literature, the rotator cable likely plays an important role in the biomechanics of the intact and torn rotator cuff. Published data addressing the performance of MR imaging in the evaluation of the rotator cable is rather limited. The purpose of this exhibit is threefold: 1) to describe the normal gross anatomy, histology, as well as the MR imaging anatomy of the rotator cable, 2) to describe the role of imaging as it pertains to the cable's function in the biomechanics of the intact and torn rotator cuff, 3) to underscore the clinical significance of the cable in terms of classification and treatment of rotator cuff tears. Introduction to the most current knowledge on the origin, distribution, and insertions of the rotator cable using gross anatomy, histology, and MR imaging correlation will be presented. Emphasis will be placed on the MR appearance of the rotator cable in orthogonal imaging planes in both intact and torn rotator cuffs. The role of the rotator cable in the setting of rotator cuff pathology will be underscored using MRI, including its potential contributions to the geometric configuration of cuff tears, altered glenohumeral biomechanics, and fatty degeneration of the rotator cuff musculature. Lastly, a review of the clinical importance of the rotator cable will be provided focused on the effect of the cable's integrity in the management of rotator cuff tears