Identifying anatomic landmarks and median nerve characteristics for the analysis of persistent carpal tunnel syndrome using magnetic resonance imaging (MRI).

OBJECTIVE: Carpal tunnel syndrome (CTS) is the most common nerve entrapment neuropathy in the USA. In this study, we define anatomical landmarks to assess symptomatic and asymptomatic cohorts with persistent CTS using MRI imaging. MATERIALS AND METHODS: Distal vs proximal incomplete release was determined using the distal most aspect of the hook of hamate and the distal wrist crease. An incomplete release showed the transverse carpal ligament (TCL) intact at either boundary. Twenty-one patients with persistent CTS were analyzed for incomplete release, median nerve enlargement and T2 signal hyperintensity, and flattening ratio using postoperative wrist MRI. These findings were compared to a ten-patient asymptomatic persistent CTS control group. Fisher's exact and a Student's two-tailed t-tests were used to determine statistical significance. RESULTS: In the symptomatic persistent CTS group, 13 (61.9%) incomplete releases were identified, 5 (38.5%) incomplete distally, and 1 (7.7%) incomplete proximally. There was no statistical significance in the rate of incomplete releases when compared to the asymptomatic group (p = 1.00). T2 signal hyperintensity and enlargement at the site of release showed no statistical significance, (p = 0.319 and p = 0.999, respectively). The mean flattening ratio at the site of release in the symptomatic group (2.45 ± 0.7) was statistically significant compared to the asymptomatic group (1.48 ± 0.46), (p = 0.007). CONCLUSION: Utilizing the established landmarks, the full length of the TCL can be assessed via MRI. Additionally, evaluation of the median nerve flattening ratio at the level of the incomplete release may be utilized as an aid to the clinical management of persistent CTS.

Experience with ultrasound neurography for postoperative evaluation of targeted muscle reinnervation.

Targeted muscle reinnervation (TMR) was originally developed as a means for increasing intuitive prosthesis control, though later found to play a role in phantom limb pain and neuroma prevention. There is a paucity of literature describing the clinical course of patients with poor TMR surgical outcomes and the value of imaging in the postoperative recovery period. This report will illustrate the potential utility of ultrasound neurography to accurately differentiate TMR surgical outcomes in two patients that received upper extremity amputation and subsequent reconstruction with TMR. Ultrasound evaluation of TMR sites in patient 1 confirmed successful reinnervation, evident by nerve fascicle continuity and eventual integration of the transferred nerve into the target muscle. Conversely, the ultrasound of patient 2 showed discontinuity of the nerve fascicles, neuroma formation, and muscle atrophy in all three sites of nerve transfer, suggesting an unsuccessful procedure and poor functional recovery. Ultrasound neurography is uniquely able to capture the longitudinal trajectory of rerouted nerves to confirm continuity and eventual reinnervation into muscle. Therefore, the application of ultrasound in a postoperative setting can correctly identify instances of failed TMR before this information would become available through clinical evaluation. Early identification of poor TMR outcomes may benefit future patients by fostering the discovery of failure mechanisms and aiding in further surgical planning to improve functional outcomes.

Novel illuminoss photodynamic bone stabilization system: normal and post-operative complication imaging findings in the emergency setting.

The mainstay orthopedic surgical technique for fracture fixation involves metal plates, screws, and rods. While these methods are effective, they exhibit high rates of complications within specific populations, particularly among patients with pathologic and insufficiency fractures. IlluminOss represents a novel photodynamic bone stabilization system, approved for use in multiple countries, that serves as an alternative to traditional fracture fixation approaches for patients experiencing pathologic, traumatic, and fragility fractures. Despite the initial success of the system in fostering fracture healing, no study has comprehensively examined the radiological attributes of the IlluminOss Stabilization system thus far. The emergency radiologist is often the first point of imaging identification and interpretation for patients presenting with suspected postoperative complications, requiring evolving knowledge of both expected and atypical appearances for novel surgical implants. This manuscript's objective is to delve into the design and clinical application of IlluminOss, scrutinize relevant normal imaging findings across various modalities, and delineate potential complications associated with the IlluminOss Stabilization system for traumatic, pathologic, and fragility fractures that are increasingly encountered in the emergency department setting.

Lower extremity peripheral nerve pathology: Utility of preoperative ultrasound-guided needle localization before operative intervention.

Historically, the use of ultrasound (US) in the management of peripheral nervous system (PNS) pathology has been limited to diagnostic confirmation or guidance for interventional injections. This technical case series will demonstrate the utility and versatility of preoperative US-guided needle localization for the excision of lower extremity neuromas and other pathology of the PNS. Five patients with symptomatic lower extremity PNS tumors were retrospectively reviewed. This case series corroborates the technical nuances of localizing lower extremity neuromas by US-guided needle and wire placement prior to operative excision. This was achieved by a multidisciplinary team that included plastic surgery, neurosurgery, and radiology. Five patients had US-guided needle localization of a lower extremity PNS target prior to operative intervention. Three patients had lower extremity neuromas of varying origins, including the lateral femoral cutaneous nerve (LFCN), saphenous nerve, and sural nerve. The remaining two patients had a sciatic nerve sheath Schwannoma and a femoral nerve glomus tumor. Under sonographic visualization, a needle was advanced to the target perimeter and withdrawn, leaving behind a percutaneous guidewire. This technique simplified the marking of the nerve course prior to dissection and led to efficient intraoperative identification of all five PNS tumors without any complications. Preoperative US-guided needle localization led to safe, accurate, and efficient perioperative and intraoperative identification of neuromas and other PNS tumors of the lower extremity prior to excision. By reducing the challenges of nerve identification in a scarred tissue bed, this multidisciplinary approach may decrease postoperative patient morbidity.

Procedural Approach to Ultrasound-Guided Geniculate Nerve Blockade for Knee Pain in Patients with OA.

ABSTRACT: Ultrasound-guided genicular nerve block can provide excellent pain control for patients with knee OA. This procedure has the advantage of providing sensory blockade with concomitant sparing of motor compromise, which is observed when the femoral and its lateral femoral cutaneous branches are blocked. Once the geniculate nerve of interest is identified, the operator can use ultrasound guidance to surround nerve fascicles with an injectate mixture of anesthetic and corticosteroid, yielding decreased pain sensation at the joint capsule. Given the role of the geniculate nerve in providing sensory innervation to the joint capsule and knee ligaments, blockade of this nerve can serve as a useful tool for managing patients with acute knee pain secondary to OA.

Current Measurement Strategies of Coronal Tibiofemoral Subluxation: A Systematic Review of Literature.

OBJECTIVE. Coronal tibiofemoral (TF) subluxation has generated interest in the last several years due to newfound clinical implications of its presence. However, controversy within the literature concerning how to measure and calculate coronal TF subluxation on radiographic imaging remains. The purpose of this study was to describe how coronal TF subluxation is being measured and calculated in the literature with the goal of describing a reproducible and validated technique for clinical adoption. MATERIALS AND METHODS. A PubMed literature search was performed in March 2020 according to PRISMA guidelines. The terms "tibiofemoral subluxation" and "tibial femoral subluxation" were included in the search. Criteria of interest included radiographic view and evaluation, anatomic landmarks used, and measurement validity. RESULTS. Review of relevant literature resulted in 744 articles, 16 of which met our inclusion criteria. A wide range of measuring techniques, anatomic landmarks, and radiographic views were used with varying validity. Full-limb radiographic views were the most common. Six studies measured the translation of the mechanical axes of the tibia and femur. Eight studies measured the translation of either femoral condyle in reference to the tibial plateau. Coordinate-based software with the iterative closest point algorithm was used in two studies. Whether coronal TF subluxation should be divided by tibial plateau width to account for knee size was controversial. CONCLUSION. A variety of approaches exist for diagnosing and quantifying coronal TF subluxation because of the lack of clear anatomic landmarks within the TF joint that can be used to measure coronal TF subluxation in the horizontal plane. Even when using the same anatomic landmarks, studies varied on how to measure coronal TF subluxation radiographically and whether knee size should be accounted for. Further studies are necessary to standardize (via inter- and intraobserver validation with a control group) an easy, reproducible, and minimally biased approach to measuring coronal TF subluxation on radiographic imaging. We believe our systematic review succinctly provides the necessary information to either develop such a tool or encourage future studies to compare existing techniques to find the most reliable and clinically useful approach for evaluating coronal TF subluxation.

MRI findings of chronic distal tendon biceps reconstruction and associated post-operative findings.

Rupture of the distal biceps tendon is becoming increasingly diagnosed due to an active aging population and an increase in diagnostic imaging opportunities. While physical exam may help in diagnosis, magnetic resonance imaging (MRI) is particularly useful in evaluating chronic rupture. Although partial tears can be managed conservatively, the gold standard treatment for a chronic distal biceps tear is anatomic reinsertion with additional use of an allograft or autograft. No study has highlighted the normal appearance and postsurgical complications seen on MRI associated with allograft or autograft usage. Clinicians and radiologists may be unaware of the normal and abnormal post-operative imaging findings and their clinical relevance. The purpose of this manuscript is to discuss the epidemiology, clinical presentation, and preoperative MRI findings of distal biceps ruptures necessitating reconstruction, to explain distal biceps tendon surgical reconstruction technique with allograft or autograft usage, to display the normal and abnormal post-operative MRI findings, and to review the clinical outcomes associated with the procedure.

Percutaneous ultrasound-guided ganglion fenestration in children: initial results.

OBJECTIVE: To evaluate our pediatric experience with percutaneous ultrasound-guided fenestration of ganglia (PUGG). MATERIALS AND METHODS: Retrospective study of pediatric patients who underwent PUGG from June 2016 to October 2018 at a free-standing tertiary referral academic children's hospital with a minimum of 6 months follow-up. Electronic medical records, picture archiving system, and post-procedural calls were utilized for patient demographics, lesion characteristics, procedure details, and recurrence. The procedure itself consisted of assessment by Child Life, application of topical anesthetic cream, sterile preparation and draping, and intra-procedural ultrasound guidance for local anesthetic instillation, ganglion aspiration, fenestration, and intra-remnant steroid instillation. Post-procedure care included an ice pack, compression dressing for 48 h, and 4 weeks of brace wear and activity restriction. RESULTS: Forty-five patients met the inclusion criteria, ages 3-18 years, mean 13.5 years, and female to male ratio of 2:1. Ganglion locations consisted of 80% (36/45) in the wrist and 20% (9/45) in other locations (elbow, ankle, and foot). Ninety-eight percent (44/45) of procedures were performed non-sedated, including 20% (9/44) between ages 7 and 11 years. 28.9% (13/45) of ganglia recurred, the earliest at 3 weeks, the latest at 10 months, and an average of 3 months' time. No complication occurred and no patients required post-procedural narcotics or Emergency Department visitation for pain control. CONCLUSION: Percutaneous ultrasound-guided fenestration of ganglia (PUGG) is a safe, minimally invasive alternative to surgical excision in the pediatric population, which can be performed without sedation and does not leave a scar.

MRI of Superior Capsular Reconstruction.

Massive irreparable rotator cuff tears can be a challenging problem for arthroscopists in the perioperative setting because the typical treatment, reverse total shoulder arthroplasty, may not be the best option for all patients. Superior capsular reconstruction (SCR) is an advancing treatment option for patients with rotator cuff tears that are neither amenable to primary repair nor ideal for arthroplasty. Patient selection, which is strongly dependent on preoperative imaging findings, is an important step in obtaining favorable surgical outcomes. The tissue quality and tear type are particularly important when considering SCR for a patient. When unsuccessful SCR is suspected, postoperative MRI of the shoulder offers the surgeon and radiologist a means of evaluating the integrity and fixation of the graft. Fluid-sensitive MRI sequences are best for examining the final SCR construct, with high-signal-intensity fluid interruptions within the graft and the presence or worsening of shoulder arthropathy indicating graft failure. The indications for SCR are discussed, and the normal postoperative MRI findings after SCR are described in this review. In addition, the common types of SCR graft failure and associated imaging findings are described and illustrated. ©RSNA, 2020.

MRI appearance of the different meniscal ramp lesion types, with clinical and arthroscopic correlation.

BACKGROUND: Meniscal ramp lesions have been defined as longitudinal vertical peripheral tears of the medial meniscus involving the posterior meniscocapsular ligament, meniscotibial ligament, and/or the red-red zone of the posterior horn. They are heavily associated with anterior cruciate ligament injuries, and because of their potentially important biomechanical role in knee stabilization, injuries to this region may require surgical repair. However, due to their location and lack of general knowledge regarding their different types and associated appearances on magnetic resonance imaging, ramp lesions are routinely underreported. This is compounded by the fact that ramp lesions are also often overlooked during conventional anterior portal arthroscopy when direct visualization is not achieved. PURPOSE: To demonstrate MRI appearances and arthroscopic findings of the different types of meniscal ramp lesions, in the hopes of improving their detection on pre-operative imaging.

Enthesopathy-An Underappreciated Role in Osteoarthritis?

Osteoarthritis (OA) continues to be a debilitating disease worldwide, to date, no therapies have been definitely proven to modify disease progression or moderate symptom relief long term other than joint replacement. A contributing factor may be the lack of attention to the potential role of the periarticular enthesis and development and progression of OA. The enthesis is the site of attachment for a tendon, ligament, or joint capsule to the bony skeleton, thereby allowing centralized transmission and dissipation of mechanical loads. Because of this design, the enthesis is a site of stress concentration subject to inflammation during sports-related activities or spondyloarthropathies, which may lead to long-term degeneration. Our hypothesis is that functional incompetence of the enthesis resulting from either degenerative or inflammatory changes could be an initiating factor for OA and may thus provide a novel basis for the development of future disease management in this phenotype of patients.

Significance of incidental intra-articular and peri-articular FDG avid foci on PET/CT.

BACKGROUND: Positron emission tomography/computed tomography (PET/CT) is a useful imaging adjunct in patients with sarcoma. Intra-articular and peri-articular 18F-fluoro-2-deoxy-D-glucose (FDG) avid lesions are often discovered incidentally. PURPOSE: To describe the etiology, appearance, and standardized uptake values (SUV) of incidentally detected FDG avid intra-articular and peri-articular foci in patients with sarcoma. MATERIAL AND METHODS: The institutional sarcoma database between November 2011 and November 2016 was retrospectively reviewed. Patients were included if a PET/CT scan was performed and an FDG avid intra-articular or peri-articular focus was found that was distinct from the primary sarcoma. RESULTS: The majority of FDG avid foci represented benign, non-physiologic conditions such as osteoarthritis, enthesopathy, bursitis, and post-surgical changes. Six patients each had radiographic features consistent with tenosynovial giant cell tumor (TSGCT) and metastatic disease, respectively. Lower SUV, bilateral findings, and the absence of metastatic disease elsewhere were associated with benign etiologies. There was a statistically significant difference between the mean SUV measured in patients with TSGCT and those with benign, non-physiologic conditions ( P < 0.001). The difference between the benign, non-physiologic cohort and the cohort with widespread metastatic disease did not reach statistical significance ( P = 0.07). CONCLUSIONS: In patients with soft-tissue or osseous sarcomas, isolated FDG avid intra-articular or peri-articular foci without additional metastatic lesions likely represent benign processes. Isolated intra-articular or peri-articular foci with significantly elevated SUV measurements were favored to represent TSGCT in this series.

Magnetic resonance imaging of the quadriceps tendon autograft in anterior cruciate ligament reconstruction.

BACKGROUND: Quadriceps tendon (QT) autograft is emerging as a popular technique for primary anterior cruciate ligament (ACL) reconstruction. Studies have shown that it has comparable outcomes to bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts while mitigating post-operative complications associated with these grafts. PURPOSE: To provide a literature summary of the important pre- and post-operative magnetic resonance imaging (MRI) findings of the quadriceps tendon and pertinent postoperative complications associated with the QT harvest. Radiologists should be familiar with MR findings after autologous graft harvest of the quadriceps tendon for reconstruction of the ACL. LEVEL OF EVIDENCE: Level IV.

MRI findings in bucket-handle tears of the triangular fibrocartilage complex.

The triangular fibrocartilage complex (TFCC) is an intricate ligamentous and cartilaginous structure that helps transmit axial load across the wrist, and provide stability to the ulnocarpal and distal radioulnar joints (DRUJ). Because the blood supply to the TFCC varies depending on location, certain types of tears are more amenable to surgical repair than others. Since Palmer proposed his classification system of TFCC tears in 1989, only 1 case of a "bucket-handle" type tear has been reported. In this article, we describe two new cases of bucket-handle tears of the TFCC. In both cases, the torn fragment was displaced into a previously undescribed location (intra-articular DRUJ and prestyloid recess). Because this type of injury pattern has not been previously well characterized in the literature and such cases rarely reported, MRI findings have not been fully described and its implications on clinical management have largely yet to be determined.

MRI findings associated with microscopic residual tumor following unplanned excision of soft tissue sarcomas in the extremities.

INTRODUCTION: MRI is often used to determine the presence of residual disease following unplanned excisions (UPE) of soft tissue sarcomas (STS). We sought to identify MRI features associated with histologic evidence of residual disease after TBE. MATERIALS AND METHODS: This was an IRB-approved retrospective review of 27 patients with R1-type UPE of STS over a 32-month period, with subsequent MRI and TBE. MRI studies were retrospectively evaluated to determine depth of tissue involvement, presence of nodular enhancement, and maximum length of soft tissue edema normalized to extremity size. MRI findings were correlated with histology from unplanned excision and TBE. RESULTS: Among the 21 subjects, there were 13 males and 8 females, mean age 58. Eighteen of 21 STS were grade 2 or 3. Deep compartments were involved in 5/21 cases. Original margins were positive in 17/21 UPE, with inadequate margin assessment in the remaining 4 cases. Residual tumor was present at TBE in 11/21 cases; it was found in 4/6 cases with nodular enhancement and 7/15 cases without nodular enhancement (sensitivity = 0.36; specificity = 0.80; PPV = 0.67; NPV = 0.53). Increased extent of soft tissue edema increased the likelihood of residual tumor at TBE (OR = 35.0; 95% CI = 1.6 to 752.7; p = 0.023). CONCLUSION: Nodular enhancement is neither sensitive nor specific in predicting residual microscopic tumor in TBE following UPE. Extensive soft tissue edema on MRI after UPE increases the likelihood of finding a residual microscopic tumor, justifying ample margins at TBE and consideration of adjuvant therapy.

The glenoid track: a review of the clinical relevance, method of calculation and current evidence behind this method.

In the setting of bipolar bone injury, orthopedic surgeons are currently making use of the glenoid track method to guide surgical management. Using preoperative CT or MR imaging, this method allows the identification of patients who are more likely to fail a primary capsuloligamentous Bankart repair. As the glenoid track method becomes increasingly used in preoperative planning, it is important for the radiologist to become familiar with its concept and method of calculation. This review article aims to concisely summarize the current literature and the clinical implications of the glenoid track method.

Anterior cruciate ligament reconstruction tunnel size: causes of tunnel enlargement and implications for single versus two-stage revision reconstruction.

Anterior cruciate ligament (ACL) reconstructions have increased over the past 25 years. The increased incidence of ACL reconstructions has translated into a larger number of graft failures and revision ACL procedures. It is important to understand the causes of graft failure when evaluating for a revision ACL reconstruction and to appreciate changes in tunnel anatomy over time prior to planning revision surgery. In this manuscript, tunnel size for ACL reconstruction and implications for single-stage versus two-stage revision ACL reconstruction will be discussed, as well as causes of tunnel enlargement, including mechanical and biological factors.

Anatomic Relationship and Imaging Relevance of the Perforating Branches of the Peroneal Vessels to the Anterior Talofibular Ligament.

BACKGROUND: Patients frequently present to the emergency department after ankle injuries, and the anterior talofibular ligament (ATFL) is commonly damaged. Musculoskeletal ultrasound (US) can help to make a rapid diagnosis. There is a paucity of literature describing techniques to image the ATFL with US, and the complex ankle anatomy and potential pitfalls make imaging challenging. OBJECTIVE: Our aim was to estimate prevalence of perforating branches (PBs) of the peroneal vessels and determine their most frequent position relative to the ATFL. If these vessels are located in a predictable position at the level of the ATFL, they may serve as a sonographic landmark for the correct imaging plane. METHODS: Magnetic resonance imaging (MRI) scans of 105 ankles were reviewed to determine the PB prevalence and location at the ATFL. Inter-observer agreement was determined. Additionally, 16 ankles from 8 asymptomatic subjects were scanned using a high-frequency linear transducer and PB prevalence and location were noted. RESULTS: By MRI, PBs were detected in 85% of the ankles and 93% of ankles after consensus. In 73% of cases with agreed PB visualization, vessels assumed a medial position with respect to the ATFL. By US, PBs could be seen in 100% of cases, with the arterial PB seen in 81% of cases and assuming a medial position in 88%. CONCLUSIONS: PBs are often present, have a predictable course, and may be useful to help optimize US probe positioning when assessing the ATFL.