Faculty Bibliography

Following anterior shoulder instability surgery, patients may present with new or recurrent symptoms. Postoperative imaging, including MR imaging, may be obtained for these patients to assess the integrity of the repaired tissues and orthopedic fixation hardware or grafts. Familiarity with different operative techniques and their expected normal appearances and complications helps in the appropriate interpretation of these imaging studies. This article provides an overview of the current treatment guidelines and surgery options for patients with anterior shoulder instability and reviews the normal and abnormal postoperative imaging appearances of the shoulder joint after treatment with the most common surgical stabilization techniques.

OBJECTIVE:To compare MRI with 3D reconstructions and 3D-CT with respect to assessment of glenoid wear in osteoarthritic shoulders. METHODS:3D reconstructions were generated for CT and MR (utilizing the Dixon technique) imaging performed on 29 osteoarthritic shoulders. Two reviewers independently performed glenoid morphometric measurements and evaluated glenoid erosion. Mean differences between the two modalities were calculated. Inter-observer agreement was calculated using kappa coefficient. RESULTS:The combined mean absolute difference (bias) in glenoid version between 3D-CT and 3D-MRI was 2.7° ± 1.6° (range 0.15-7.85, P value = 0.7). The combined mean absolute difference in glenoid inclination between 3D-CT and 3D-MRI was 6.8° ± 4.1° (range 0.8°-15.75°, P value = 0.17). No significant inter-reader variation in glenoid version and inclination measurements on 3D-CT and 3D-MRI was found (P > 0.05). The inter-reader reliability for both CT and MRI was high for Walch grading of glenoid bone loss (κ = 1, κ = 0.81, respectively). CONCLUSIONS:3D-MRI is comparable to 3D-CT with respect to axial glenoid bone loss, as measured by glenoid version. However, for coronal bone loss estimation, measured by glenoid inclination, 3D-CT remains the gold standard. Thus, 3D-MR can be used as an alternative for preoperative assessment of glenoid version in arthritic shoulders.

The posteromedial and posterolateral corners of the knee are important areas to consider when assessing the patient with a possible knee injury. An understanding of the anatomy, associated biomechanics, and typical injury patterns in these regions will improve the value that the radiologist interpreting the MRIs brings to this patient population.

OBJECTIVE:To determine the rate of infection in patients with suspected hip septic arthritis who underwent image-guided aspiration (IHA) resulting in dry-tap, diagnostic value of subsequent lavage and re-aspiration, and if pre-aspiration MRI can help prevent a dry tap. MATERIALS AND METHODS/METHODS:Retrospective review between 2010 to 2020 identified native hip (NH) and total hip arthroplasty (THA) patients who had a dry-tap following aspiration for suspected infection or periprosthetic joint infection (PJI). Serology tests, lavage/re-aspiration volumes, and aspirate cell-count/culture were assessed. On pre-aspiration MRI, presence/grade of joint effusion (JE), pseudocapsule dehiscence (PD), extraarticular fluid and sinus-tract were recorded. RESULTS:Out of 215 included dry-taps, 185 (86.0%) were non-infected and 30 (13.9%) infected. In subgroup analysis, 64/71(90.1%) NH and 121/144(84.0%) THA dry-taps were non-infected. Pre-aspiration MRI of THA group with dry-tap showed significant findings; PD with extraarticular fluid (8/12, 66.7%) and sinus tract (7/12, 58.3%) were higher in the infected compared to non-infected group (5/42, 11.9% and 0/42, 0.0%) (both p < 0.001). Among THA group, polymorphonuclear-leukocytes > 80% was present in 8/9 (88.9%) of infected versus 4/28 (14.3%) non-infected group (p < 0.001). Multivariable regression showed PD (p = 0.005) and JE (p = 0.042) being significant independent predictors of PJI, similarly the elevated CRP (p = 0.044) and JE (p = 0.017). CONCLUSION/CONCLUSIONS:Majority of patients suspected of hip joint infection with dry-tap were non-infected. Synovial PMN% following lavage maintains high sensitivity for detection of PJI. In patients with THA, PD and subsequent extraarticular collection can be associated with dry-tap therefore, pre-aspiration MRI can help determine their presence and plan the aspiration.

»:Pectoralis major (PM) tendon tears are predominantly seen in young men, and the majority of tears occur as tendon avulsions involving the sternal head. Weightlifting, specifically bench-pressing, and sporting activities with eccentric overloading of the PM tendon are the 2 most common activities that result in PM injury. »:Early surgical repair or reconstruction should be offered to younger, active patients with a complete PM tear; the majority of the patients undergoing surgical repair achieve good-to-excellent outcomes. »:Nonsurgical treatment of a complete PM tear is an option but will result in cosmetic deformity and a deficit in adduction strength of the arm. Outcomes after nonsurgical treatment of complete PM tears are less satisfactory than those obtained after surgical treatment. »:Currently, there is no consensus on the chronological definition of PM tears (acute versus chronic), the critical time limit for performing surgical repair, the ideal fixation device (cortical button, bone tunnel, or suture anchors), the indications for allograft use, and the ideal rehabilitation protocol after treatment of PM tears.

Magnetic resonance imaging provides a comprehensive evaluation of the shoulder including the rotator cuff muscles and tendons, glenoid labrum, long head biceps tendon, and glenohumeral and acromioclavicular joint articulations. Most institutions use two-dimensional sequences acquired in all three imaging planes to accurately evaluate the many important structures of the shoulder. Recently, the addition of three-dimensional (3D) acquisitions with 3D reconstructions has become clinically feasible and helped improve our understanding of several important pathologic conditions, allowing us to provide added value for referring clinicians. This article briefly describes techniques used in 3D imaging of the shoulder and discusses applications of these techniques including measuring glenoid bone loss in anterior glenohumeral instability. We also review the literature on routine 3D imaging for the evaluation of common shoulder abnormalities as 3D imaging will likely become more common as imaging software continues to improve.

BACKGROUND:Routine use of adjunct intraprocedural fresh frozen biopsy (FFP) or point-of-care (POC) cytology at the time of image-guided biopsy can improve diagnostic tissue yields for musculoskeletal neoplasms, but these are associated with increased costs. OBJECTIVE:This study aimed to ascertain the most cost-effective adjunctive test for image-guided biopsies of musculoskeletal neoplasms. METHODS:This expected value cost-effectiveness microsimulation compared the payoffs of cost (2020 United States dollars) and effectiveness (quality-adjusted life, in days) on each of the competing strategies. A literature review and institutional data were used to ascertain probabilities, diagnostic yields, utility values, and direct medical costs associated with each strategy. Payer and societal perspectives are presented. One- and two-way sensitivity analyses evaluated model uncertainties. RESULTS:The total cost and effectiveness for each of the strategies were $1248.98, $1414.09, $1980.53, and 80.31, 79.74, 79.69 days for the use of FFP, permanent pathology only, and POC cytology, respectively. The use of FFP dominated the competing strategies. Sensitivity analyses revealed FFP as the most cost-effective across all clinically plausible values. CONCLUSIONS:Adjunct FFP is most cost-effective in improving the diagnostic yield of image-guided biopsies for musculoskeletal neoplasms. These findings are robust to sensitivity analyses using clinically plausible probabilities.