Harry G. Greditzer

MRI for the preoperative evaluation of femoroacetabular impingement

AbstractFemoroacetabular impingement (FAI) refers to a condition characterized by impingement of the femoral head–neck junction against the acetabular rim, often due to underlying osseous and/or soft tissue morphological abnormalities. It is a common cause of hip pain and limited range of motion in young and middle-aged adults. Hip preservation surgery aims to correct the morphological variants seen in FAI, thereby relieving pain and improving function, and potentially preventing early osteoarthritis. The purpose of this article is to review the mechanisms of chondral and labral injury in FAI to facilitate an understanding of patterns of chondrolabral injury seen on MRI. Preoperative MRI evaluation of FAI should include assessment of osseous morphologic abnormalities, labral tears, cartilage status, and other associated compensatory injuries of the pelvis. As advanced chondral wear is the major relative contraindication for hip preservation surgery, MRI is useful in the selection of patients likely to benefit from surgery. Teaching points • The most common anatomical osseous abnormalities predisposing to FAI include cam and pincer lesions. • Morphological abnormalities, labral lesions, and cartilage status should be assessed. • In cam impingement, chondral wear most commonly occurs anterosuperiorly.• Pre-existing advanced osteoarthritis is the strongest predictor of poor outcomes after FAI surgery. • Injury to muscles and tendons or other pelvic structures can coexist with FAI.

Effects on the Tarsal Tunnel Following Malerba Z-type Osteotomy Compared to Standard Lateralizing Calcaneal Osteotomy

Background: Tarsal tunnel syndrome is a known complication of lateralizing calcaneal osteotomy. A Malerba Z-type osteotomy may preserve more tarsal tunnel volume (TTV) and decrease risk of neurovascular injury. We investigated 2 effects on the tarsal tunnel of the Malerba osteotomy compared to a standard lateralizing osteotomy using a cadaveric model: (1) the effect on TTV as measured by magnetic resonance imaging (MRI) and (2) the proximity of the osteotomy saw cuts to the tibial nerve. Methods: Ten above-knee paired cadaveric specimens underwent MRI of the ankle to obtain a baseline measurement of TTV. One foot in each pair received a standard lateralizing calcaneal osteotomy, with the other foot receiving a Malerba osteotomy. MRIs were performed after each of 3 increasing amounts of lateral displacement, which were accompanied by increasing amounts of wedge resection in the Malerba osteotomy group. TTV was measured on MRI using previously described and validated parameters. Differences in TTV with osteotomy type, displacement, and their interaction were assessed with generalized estimating equations. After all MRIs were completed, each specimen was dissected and the nearest distance of tibial nerve branches to the osteotomy site was measured. Results: Baseline TTV averaged 13 229 ± 2354 mm3 and did not differ between groups (P = .386). TTV decreased on average by 7% after the first translation, 14% after the second, and 27% after the third (P < .005 for each). The magnitude of the decrease in TTV did not differ between those specimens with standard osteotomies versus those with Malerba osteotomies (P = .578). At least one of the major branches of the tibial nerve crossed the osteotomy site in 5 of 5 specimens that received the Malerba osteotomy versus 2 of 5 that received a standard osteotomy. Conclusion: Regardless of osteotomy type, lateralizing calcaneal osteotomy decreased TTV. In all specimens, the osteotomy was at the level of branches of the tibial nerve. Clinical Relevance: Our results demonstrate that lateralizing calcaneal osteotomies must be performed with care to avoid excessive lateral translation as well as direct nerve injury on the nonvisualized medial side of the calcaneus.

Ultrasound-Guided Percutaneous Long Head of the Biceps Tenotomy: a Novel Technique with Case Report

Lesions of the long head of the biceps (LHB) tendon linked with rotator cuff tears can be responsible for considerable shoulder pain and dysfunction [10]. The two most commonly performed procedures for biceps pathology by orthopedic surgeons today are arthroscopic biceps tenotomy and tenodesis. Although the optimal surgical procedure is controversial, there is considerable agreement that operative treatment provides significant pain relief, with no major functional impairment [4]. While ultrasound-guided percutaneous tenotomy of the LHB tendon has been reported in cadavers [7], to our knowledge, no one has successfully reported the procedure in a patient. In the ever-changing health care environment, a less invasive procedure that can be performed without the risks and costs of anesthesia and surgery could be of great benefit. This is particularly important for patients who are not ideal surgical candidates due to comorbid conditions (i.e., cardiac disease, pulmonary insufficiency).

MRI findings of spinal accessory neuropathy

AIM To characterise the magnetic resonance imaging (MRI) appearance of patients with spinal accessory nerve (SAN) denervation. MATERIAL AND METHODS Twelve patients who had SAN denervation on electromyography (EMG) were included. The sternocleidomastoid and trapezius muscles and the SAN were assessed using MRI. RESULTS Trapezius muscle atrophy was seen in 11 (92%), and of those patients, T2/short tau inversion recovery (STIR) signal hyperintensity was also demonstrated in seven (58%). All three patients with prior neck surgery had scarring around the SAN, and one of these patients demonstrated a neuroma, which was confirmed surgically. CONCLUSION Features of SAN neuropathy on MRI include atrophy and T2/STIR signal hyperintensity of the trapezius, and in patients who have had posterior triangle neck surgery, scarring may be seen around the nerve.

MRI Evaluation of Femoroacetabular Impingement After Hip Preservation Surgery

OBJECTIVE This article reviews the surgical treatment options for femoroacetabular impingement (FAI), including labral repair and osteochondroplasty, and the expected postoperative appearance on MRI. Complications, including residual osseous deformities, chondral injury, adhesions, femoral neck stress fractures, osteonecrosis, instability, malpositioned suture anchors, and infection, will also be discussed. CONCLUSION Knowledge of the surgical treatment of FAI can assist in improving our understanding of the expected postoperative MRI appearance and in evaluating surgical complications.

How Can I Be Politically Involved in Radiology? A Report of the Florida Radiology Resident's Challenge

BACKGROUND We all know the importance of learning when it comes to our future as radiologists. That is what we do every day in residency, and we are, collectively, very good at it. Although there are well-defined systems for acquiring the knowledge required to be excellent radiologists, little attention is paid to the forces that create the professional environment in which radiologists work and receive financial compensation. With that background, it was our intention both to raise awareness among Florida radiology residents of professional and governmental regulatory forces at work locally and nationally and to propose an efficient, accessible method to have an impact on these forces through the Resident’s Challenge. Where did this desire to effect change begin? In May 2011, a group of residents from across the state of Florida attended the AMCLC in Washington, DC. At the conference, we became aware of the issues facing the practice of radiology, including reimbursement, accountable care organizations, and the potential impact of new and proposed legislation. Moreover, the discussion involving a great number of these issues, which directly affect our ability to work and to receive compensation, does not include radiologists, hospitals, or insurers. Instead, legislators in both Washington, DC and our respective state capitals make many of the decisions. We had the opportunity to visit with our state legislators and their staff members to voice our concerns directly. During the visit, we were provided with ample evidence that if radiologists do not speak up, others will gladly make the decisions for them, often to their detriment. Thus, we knew that we wanted to become more involved because grassroots efforts from residents are essential to the political success of our organizations and profession [1].

Distal rupture of the adductor longus in a skier

Acute adductor longus ruptures occur infrequently and have been rarely described in the literature. Schlegel et al. reviewed a series of adductor longus tendon ruptures and found that all ruptured proximally. A 42-year-old man with right hip pain 3 weeks following a skiing injury underwent magnetic resonance imaging (MRI), which demonstrated a distal adductor longus avulsion. The diagnosis of acute adductor longus injury can be difficult on physical examination alone, but MRI can accurately depict the site of injury. Surgery may be indicated for a proximal avulsion, but a distal injury may heal with nonoperative treatment, as in our case.

Imaging of the Clavicle

Radiography is the initial modality for imaging of the clavicle in most instances, and accordingly, the projections necessary to optimize visualization of the clavicle, acromioclavicular joint, and sternoclavicular joint are described and discussed. Recent developments in computed tomography (CT) allow for enhanced osseous rendering and more accurate visualization of hardware failure and related complications to clavicular fractures. However, it is important to recognize that magnetic resonance imaging (MRI) has extended the feasibility of prescribing advanced imaging to aid in perioperative planning and post-operative assessment by its superior soft tissue contrast and direct multi-planar imaging capability. Refinements and new sequences in MRI achieve finer delineation of the soft tissues, cartilage and bone; specifically, these may offer insights into the assessment of tissue quality and integrity following injury to the sternoclavicular or acromioclavicular joints as well as complex reconstructions. Finally, the procedural use of ultrasound to guide injections of the acromioclavicular and sternoclavicular joints for either diagnostic or therapeutic injections is also practically described.

Prevalence of Os Styloideum in National Hockey League Players

Background: Os styloideum describes an accessory carpal ossicle between the trapezoid, the capitate, and the second and third metacarpals. Injuries to this tissue have been described as part of the carpal boss syndrome. While the etiology of os styloideum remains uncertain, it may represent a physiologic response to altered loading forces in the wrist, similar to the development of cam-type deformity in the hips of ice hockey players or the Bennett lesion in the shoulders of baseball pitchers. Hypothesis: Professional hockey players will have a higher prevalence of os styloideum compared with the general population. Study Design: Case series. Level of Evidence: Level 4. Methods: A retrospective review of 16 professional hockey players from 4 different National Hockey League (NHL) teams who underwent unilateral imaging of the wrist was performed. Seventeen wrists were reviewed for the presence of os styloideum. Results: Thirteen of 16 players (81%) had an os styloideum, representing an increased prevalence compared with the general population. Previous clinical and cadaveric studies estimated a general prevalence of up to 19% (P < 0.001). For the 10 players who had their leading wrist scanned, 9 had an os styloideum (90%). Ten of 11 (91%) players demonstrated a bone marrow edema pattern within the metacarpal and the os styloideum on magnetic resonance imaging. There was no significant association between the presence of an os styloideum and the player’s position, leading wrist, or years in the league. Conclusion: There appears to be an increased prevalence of os styloideum among NHL players, and team physicians should consider this finding while formulating a differential diagnosis for dorsal wrist pain. Clinical Relevance: This study identified NHL players as having an increased prevalence of os styloideum compared with the general population. By doing so, these findings represent an opportunity to enhance our understanding of the etiology, clinical significance, and treatment of os styloideum.

Sequential MRI Study of Graft Integrity and Signal Following Pediatric All-epiphyseal ACL Reconstruction: Does the “Sharp Turn” at the Socket of the Distal Femoral Aperture Matter?

Objectives: To analyze graft structure and signal with particular emphasis on the distal femoral socket aperture following all-epiphyseal ACLR using hamstring autografts with sequential MRI in skeletally immature athletes. Methods: Retrospective cohort study of 23 skeletally immature patients who underwent ACLR by the same surgical team at a tertiary center during 2011-2013. Athletes had at least two follow-up MRIs, the first MRI 6-12 months after surgery and the second MRI >18 months, were included. Exclusion criteria included those athletes with inMRI follow-up (6) or with a failure of their reconstructions (1). All athletes were treated with an arthroscopic all-inside, all-epiphyseal ACLR, using hamstring autograft, secured with adjustable loop cortical buttons on both tibia and femur. MRI images were analyzed independently and blinded by an orthopaedic surgery fellow and a musculoskeletal radiology fellow. Using a GE Functional Analysis Software, the signal intensity (SI) of the graft was measured in 5 different locations: 1) femoral tunnel, 2) intra-articular proximal turn, 3) midsubstance, 4) intra-articular distal turn, and 5) tibial tunnel. Values were normalized to cortical bone density. The amount of perigraft scarring and synovitis was analyzed. An intraclass correlation coefficient was used to quantify inter-rater reliability, non-parametric Wilcoxon test for perigraft scarring and synovitis, one-way ANOVA to test if significant differences of SI were seen between the different graft locations, and a 2-tailed student t-test for SI changes from 1st to 2nd MRI. Results: The study included 16 patients (5 girls and 11 boys), with an average age at surgery of 11.9 years (range 10-15). The first follow-up MRI was on average at 8.4 months (range 6-12 months), while the 2nd MRI was on average 30.7 months (range 18-40) after surgery. Intra-class correlation coefficients were above 0.7 for all measurements, indicating an excellent concordance between observers. Perigraft scarring tended to reduce with follow-up (p=0.057) though not significantly, while synovitis had a significant reduction over time (p=0.01). On average, normalized SI showed no significant differences between measurements taken in different regions of the graft (p=0.58). When comparing the graft SI from 1st to 2nd MRI, no significant differences were found in any of the locations: femoral tunnel (p=0.14), proximal turn (p=0.11), midsubstance (p=0,29), intra-articular distal (p=0.10), or tibial tunnel (p=0.15). All 16 athletes returned to their prior sport at the same level of performance without re-injury. Conclusion: ACL grafts in skeletally immature patients with all-epiphyseal reconstructions maintain a stable intensity signaling at long term MRI follow-up, with no significant signal reduction over time. Despite the sharp turn created at the distal femoral socket aperture in physeal-sparing reconstructions, no particular anatomic location of the graft presents significantly different signal intensity over others. This is the first sequential mri study in pediatric epiphyseal acl reconstructions demonstrating postoperative maintenance of graft integrity and graft signal.