CT Arthrography of the Elbow: What Radiologists Should Know.

Computed tomography (CT) arthrography is a quickly available imaging modality to investigate elbow disorders. Its excellent spatial resolution enables the detection of subtle pathologic changes of intra-articular structures, which makes this technique extremely valuable in a joint with very tiny chondral layers and complex anatomy of articular capsule and ligaments. Radiation exposure has been widely decreased with the novel CT scanners, thereby increasing the indications of this examination. The main applications of CT arthrography of the elbow are the evaluation of capsule, ligaments, and osteochondral lesions in both the settings of acute trauma, degenerative changes, and chronic injury due to repeated microtrauma and overuse. In this review, we discuss the normal anatomic findings, technical tips for injection and image acquisition, and pathologic findings that can be encountered in CT arthrography of the elbow, shedding light on its role in the diagnosis and management of different orthopedic conditions. We aspire to offer a roadmap for the integration of elbow CT arthrography into routine clinical practice, fostering improved patient outcomes and a deeper understanding of elbow pathologies.

Semiquantitative index of symptomatic minor instability of the lateral elbow at CT arthrography (SMILE index): clinical applicability and reproducibility study.

OBJECTIVE: To assess the applicability of a semiquantitative index for symptomatic minor instability of the lateral elbow (SMILE). MATERIALS AND METHODS: CT arthrograms of consecutive patients with lateral elbow pain who underwent ultrasound-guided CT arthrography at our orthopedic center between April 2019 and May 2022 were included. Images were acquired at 100 kVp and 80 mAs. An expert radiologist (R1) and a radiology resident (R2) retrospectively performed an independent, blinded evaluation of the arthrograms to assess the presence of imaging findings suggestive of elbow instability. The SMILE index (0-8) was obtained adding (I) radial head chondromalacia (0 - 1); (II) humeral capitellum chondromalacia (0 - 1); (III) humeral trochlear ridge chondromalacia (0 - 1); (IV) annular ligament laxity (0 - 2); (V) synovial thickening (0 - 1); (VI) humeroradial joint asymmetry (0 - 1); and (VII) capsular tear (0 - 1). R1 repeated the assessment after 14 days. Cohen's weighted κ statistic and raw concordance were used to appraise reproducibility. RESULTS: Eighty patients (median age 49 years, interquartile range 40-53 years, 49, 61% males) underwent CT arthrography at our center, and 10 (12%) of them underwent bilateral elbow examination, leading to 90 included CT arthrograms. Median SMILE index was 4 (IQR: 2-5) for R1, 4 (IQR: 2-5) for R2, and 4 (IQR: 2-5) for the second assessment by R1. Intra-reader agreement was excellent (κ = 0.94, concordance 87%), while inter-reader agreement was substantial (κ = 0.75, concordance 67%). CONCLUSION: The proposed SMILE index showed good reproducibility; further studies are warranted to correlate our index with clinical and surgical data. CLINICAL RELEVANCE STATEMENT: Our scoring system allows a standardized evaluation of patients with lateral elbow pain and instability suitable for application into clinical practice, complementing the orthopedic surgeon's clinical diagnosis with imaging findings that may aid treatment choices. KEY POINTS: • Lateral elbow pain is often interpreted clinically as lateral epicondylitis, but it can also encompass intra-articular pathology. • The proposed arthrographic index allows comprehensive quantification of lateral elbow pathology with good reproducibility and application times. • Our index provides the orthopedic surgeon with information regarding intra-articular findings, aiding treatment choices.

MRI radiomics-based machine learning for classification of deep-seated lipoma and atypical lipomatous tumor of the extremities.

PURPOSE: To determine diagnostic performance of MRI radiomics-based machine learning for classification of deep-seated lipoma and atypical lipomatous tumor (ALT) of the extremities. MATERIAL AND METHODS: This retrospective study was performed at three tertiary sarcoma centers and included 150 patients with surgically treated and histology-proven lesions. The training-validation cohort consisted of 114 patients from centers 1 and 2 (n = 64 lipoma, n = 50 ALT). The external test cohort consisted of 36 patients from center 3 (n = 24 lipoma, n = 12 ALT). 3D segmentation was manually performed on T1- and T2-weighted MRI. After extraction and selection of radiomic features, three machine learning classifiers were trained and validated using nested fivefold cross-validation. The best-performing classifier according to previous analysis was evaluated and compared to an experienced musculoskeletal radiologist in the external test cohort. RESULTS: Eight features passed feature selection and were incorporated into the machine learning models. After training and validation (74% ROC-AUC), the best-performing classifier (Random Forest) showed 92% sensitivity and 33% specificity in the external test cohort with no statistical difference compared to the radiologist (p = 0.474). CONCLUSION: MRI radiomics-based machine learning may classify deep-seated lipoma and ALT of the extremities with high sensitivity and negative predictive value, thus potentially serving as a non-invasive screening tool to reduce unnecessary referral to tertiary tumor centers.

CT-guided radiofrequency ablation of painful intra-articular osteoid osteoma in children: Is there a concern for cartilage damage?

OBJECTIVE: To evaluate the safety and efficacy of computed tomography-guided percutaneous radiofrequency ablation (PRFA) in the management of uncommon and technically challenging intra-articular osteoid osteoma in children. MATERIAL AND METHODS: From December 2018 to September 2022, 16 children with intra-articular osteoid osteoma, including ten boys and six girls, were treated at two tertiary centers with percutaneous CT-guided RF ablation using a straight monopolar electrode. The procedures were carried out under general anesthesia. Post-procedural clinical outcomes and adverse events were assessed through clinical follow-up. RESULTS: Technical success was achieved in all of the participating patients. Clinical success with relief of symptomatology throughout the period of follow-up was achieved in 100% of the patients. No persistence or recurrence of pain occurred during the follow-up period. No immediate or delayed adverse effects were observed. CONCLUSION: PRFA is shown to be technically feasible. Clinical improvement can be achieved with a high rate of success in the treatment of children with difficult-to-treat intra-articular osteoid osteomas.

Role of percutaneous CT-guided radiofrequency ablation in treatment of intra-articular, in close contact with cartilage and extra-articular osteoid osteomas: comparative analysis and new classification system.

PURPOSE: We investigated procedural safety, technical and clinical outcomes of the percutaneous image-guided radiofrequency ablation (PRFA) of intra-articular (IA), intra-articular close to cartilage (IACC), and extra-articular (EA) osteoid osteomas (OO). We proposed a new radiologic classification for osteoid osteoma depending on the degree and location of sclerosis which may correlate with technical failure and/or difficulties. MATERIAL AND METHODS: According to the inclusion criteria, we enrolled consecutive patients who were referred to the investigation center from June 2018 to January 2022. After clinical and CT imaging features were suggestive for the diagnosis of OO, all the patients were treated by percutaneous CT-guided RFA with a standardized technique. Biopsy of the lesion was not performed in all patients. A retrospective analysis was conducted to assess the procedure's technical, primary clinical, and secondary clinical successes, recurrence rate, and complications. We classified all the OOs according to a new proposed classification of the site and the amount of sclerosis. RESULTS: A total number of 55 patients were enrolled in our study according to the inclusion criteria. The mean age of the enrolled patients was 24.07 ± 14.71 years (ranges from 7 to 57 years). The M/F ratio was roughly 2:1. The mean follow-up was 20.18 ± 12.60 months (ranges from 2 to 44 months). EA group included 36 patients, IA included 5 and IACC included 14 patients. Technical success was achieved in all cases of IA and IACC groups. Technical success in the EA group was 97.22% (1 technical failure). Primary clinical success was 100%, 92.85%, and 91.66% for IA, IACC, and EA groups, respectively. Accordingly, the recurrence rate was 5.88% in EA, and 7.14% in IACC, while no recurrence occurred in the IA group. No complications occurred. The secondary success rate of the 3 cases of recurrence was 100%. CONCLUSIONS: PRFA proved to be a safe procedure with a high rate of success for OO treatment even in intra-articular lesions in close contact with cartilage. This study showed that the results in terms of technical and clinical success are comparable for IA OO, IACC OO, and EA OO, even if the recurrence rate was higher in EA OO. Our proposed new classification of the degree and location of sclerosis may correlate to technical failure, but further studies with a larger number of patients are needed for validation.

Arthroscopic remplissage is safe and effective: clinical and magnetic resonance results at a minimum 3 years of follow-up.

BACKGROUND: Large Hill-Sachs lesions are considered a risk factor for recurrence of instability after arthroscopic Bankart repair alone. The aim of this study was to demonstrate that remplissage is a safe procedure that effectively reduces the risk of recurrent dislocations without causing fatty degeneration of the infraspinatus at medium-term follow-up. METHODS: Patients who underwent arthroscopic Bankart repair and remplissage with a minimum 3 years of follow-up were included. Constant-Murley (CMS), American Shoulder and Elbow Surgeons (ASES), and Walch-Duplay scores were evaluated. Magnetic resonance imaging (MRI) was performed to detect the appearance of fatty infiltration inside the infraspinatus muscle, the percentage of the Hill-Sachs lesion filled by the tendon and its integration, and the onset of rotator cuff tears. RESULTS: Thirteen patients (14 shoulders) with a mean follow-up of 55.93 (± 18.16) months were enrolled. The Walch-Duplay score was 95.00 [87.25-100.00], with a return to sport rate of 100%. Both the CMS and the ASES indicated excellent results. The affected shoulders showed a statistically significant reduction in active external rotation both with the arm at the side (ER1) and with the arm at 90° of abduction (ER2) (p = 0.0005 and p = 0.0010, respectively). A reduction in infraspinatus isometric strength was found for both ER1 and ER2, but this reduction was only statistically relevant in ER2 (p = 0.0342). There was a traumatic recurrence of instability in two cases (14.28%). MRI evaluation demonstrated an absence of adipose infiltration in 50% of cases and only a minimal amount in the remaining 50%. In 12 cases (85.72%), the capsulotenodesis completely filled the lesion and good tendon-bone integration was observed. CONCLUSION: Arthroscopic remplissage provided successful clinical outcomes without fatty infiltration of the infraspinatus and with good healing of the tissues. The low risk of recurrence was associated with an objective limitation on active external rotation, but this did not influence the patients' daily or sports activities. LEVEL OF EVIDENCE: Cohort study, level of evidence 3.

Overuse-related instability of the elbow: the role of CT-arthrography.

The elbow is a complex joint whose biomechanical function is granted by the interplay and synergy of various anatomical structures. Articular stability is achieved by both static and dynamic constraints, which consist of osseous as well as soft-tissue components. Injuries determining instability frequently involve several of these structures. Therefore, accurate knowledge of regional anatomy and imaging findings is fundamental for a precise diagnosis and an appropriate clinical management of elbow instability. This review focuses particularly on the varied appearance of overuse-related elbow injuries at CT-arthrography.

Long-term evolution of calcific tendinitis of the rotator cuff: clinical and radiological evaluation 10 years after diagnosis.

BACKGROUND: Calcific tendinitis of the shoulder has a tendon involvement that could evolve to rotator cuff tear and shoulder osteoarthritis. This study aimed to evaluate the prevalence of glenohumeral osteoarthritis and rotator cuff tears in patients affected by calcific tendinitis at a minimum follow-up of 10 years after diagnosis. METHODS: Patients diagnosed with calcific tendinitis of the shoulder with a minimum follow-up of 10 years were contacted and invited for a clinical and radiological evaluation. Information on the demographics, affected and dominant side, bilateral shoulder pain, type of treatment, habits, systemic or musculoskeletal diseases, reoperation of the index shoulder, and subjective satisfaction was collected. The clinical evaluation was performed using Constant-Murley score (CMS), American Shoulder and Elbow Surgeons Score (ASES), and numerical rating scale (NRS); isometric strength in forwarding flexion and abduction was also measured. Each patient also underwent an ultrasound examination to evaluate rotator cuff tendon integrity and a shoulder radiograph to evaluate osteoarthritis. RESULTS: Seventy-nine patients were available for a phone interview, and 35 agreed to be examined. The mean age was 58.89 (± 7.9) years at follow-up. The prevalence of glenohumeral osteoarthritis was 17.14% in the study population, with significant progression in 14.29% of the cases, without rotator cuff full-thickness tears. x-Ray examination showed residual calcifications in 31 patients, with a mean diameter of 5.54 mm. In 30 cases, there was a reduction of the diameter; in 4 cases, the calcification increased in size; and in 1 case, the size did not change. The mean ASES score was 74.1 (± 22.7) in the group with calcifications larger than 2 mm and 89.4 (± 8.2) in patients with smaller calcifications (p = 0.08) without correlation with the type of treatment performed. CONCLUSIONS: Calcific tendinitis is a self-resolving disease without rotator cuff tears at long-term follow-up or degenerative glenohumeral progression. LEVEL OF EVIDENCE: 3, cohort study.

Ultrasound evaluation shows increase in laxity after partial common extensor origin detachment but not after additional lesion of the radial band of the lateral collateral ligament.

PURPOSE: The lateral elbow musculature conveys a dynamic valgus moment to the elbow, increasing joint stability. Muscular or tendinous lesions to the anterior half of the common extensor origin (CEO) may provoke a deficiency in the elbow dynamic stabilizers, regardless of their traumatic, degenerative, or iatrogenic aetiology. Furthermore, a role for the radial band of the lateral collateral ligament (R-LCL) has been postulated in the aetiology of lateral elbow pain. This study aimed to evaluate the effects of sequential lateral releases with dynamic ultrasound, evaluating its capability to detect lesions of the CEO and of the R-LCL. METHODS: Ultrasound investigation of the lateral compartment of the elbow was performed on nine cadaveric specimens with a 10 MHz linear probe in basal conditions, after the release of the anterior half of the CEO and after complete R-LCL release. The lateral joint line widening (λ) was the primary outcome parameter, measured as the linear distance between the humeral and radial articular surfaces. RESULTS: The release of the anterior half of the CEO significantly increased λ by 200% compared to the starting position (p = 0.0008) and the previously loaded position (p = 0.0015). Conversely, further release of the R-LCL caused only a marginal, non-significant increase in λ. CONCLUSIONS: Ultrasound evaluation can detect changes related to tendon tears or muscular avulsions of the CEO and can depict lateral elbow compartmental patholaxity by assessing articular space widening while scanning under dynamic stress. However, it cannot reliably define if the R-LCL is injured. Iatrogenic damage to the CEO should be carefully avoided, since it causes a massive increase in compartmental laxity.

Novel Radiographic Indexes for Elbow Stability Assessment: Part A-Cadaveric Validation.

INTRODUCTION: Elbow bony stability relies primarily on the high anatomic congruency between the humeral trochlea and the ulnar greater sigmoid notch. No practical tools are available to distinguish different morphotypes of the proximal ulna and herewith predict elbow stability. The aim of this study was to assess inter-observer reproducibility, evaluate diagnostic performance and determine responsiveness to change after simulated coronoid process fracture for three novel elbow radiographic indexes. METHODS: Ten fresh-frozen cadaver specimens of upper limbs from human donors were available for this study. Three primary indexes were defined, as well as two derived angles: Trochlear Depth Index (TDI); Posterior Coverage Index (PCI); Anterior Coverage Index (ACI); radiographic coverage angle (RCA); olecranon-diaphisary angle (ODA). Each index was first measured on standardized lateral radiographs and subsequently by direct measurement after open dissection. Finally, a type II coronoid fracture (Regan and Morrey classification) was created on each specimen and both radiographic and open measurements were repeated. All measurements were conducted by two orthopaedic surgeons and two dedicated musculoskeletal radiologists. RESULTS: All three indexes showed good or moderate inter-observer reliability and moderate accuracy and precision when compared to the gold standard (open measurement). A significant change between the radiographic TDI and ACI before and after simulated coronoid fracture was observed [TDI: decrease from 0.45 ± 0.03 to 0.39 ± 0.08 (p = 0.035); ACI: decrease from 1.90 ± 0.17 to 1.58 ± 0.21 (p = 0.001)]. As expected, no significant changes were documented for the PCI. Based on these data, a predictive model was generated, able to identify coronoid fractures with a sensitivity of 80% and a specificity of 100%. CONCLUSION: New, simple and easily reproducible radiological indexes to describe the congruency of the greater sigmoid notch have been proposed. TDI and ACI change significantly after a simulated coronoid fracture, indicating a good responsiveness of these parameters to a pathological condition. Furthermore, combining TDI and ACI in a regression model equation allowed to identify simulated fractures with high sensitivity and specificity. The newly proposed indexes are, therefore, promising tools to improve diagnostic accuracy of coronoid fractures and show potential to enhance perioperative diagnostic also in cases of elbow instability and stiffness. LEVEL OF EVIDENCE: Basic science study. CLINICAL RELEVANCE: The newly proposed indexes are promising tools to improve diagnostic accuracy of coronoid fractures as well as to enhance perioperative diagnostic for elbow instability and stiffness.

Novel Radiographic Indexes for Elbow Stability Assessment: Part B-Preliminary Clinical Study.

INTRODUCTION: The coronoid process plays a key-role in preserving elbow stability. Currently, there are no radiographic indexes conceived to assess the intrinsic elbow stability and the joint congruency. The aim of this study is to present new radiological parameters, which will help assess the intrinsic stability of the ulnohumeral joint and to define normal values of these indexes in a normal, healthy population. METHODS: Four independent observers (two orthopaedic surgeons and two radiologists) selected lateral view X-rays of subjects with no history of upper limb disease or surgery. The following radiographic indexes were defined: trochlear depth index (TDI); anterior coverage index (ACI); posterior coverage index (PCI); olecranon-coronoid angle (OCA); radiographic coverage angle (RCA). Inter-observer and intra-observer reproducibility were assessed for each index. RESULTS: 126 subjects were included. Standardized lateral elbow radiographs (62 left and 64 right elbows) were obtained and analysed. The mean TDI was 0.46 ± 0.06 (0.3-1.6), the mean ACI was 2.0 ± 0.2 (1.6-3.1) and the mean PCI was 1.3 ± 0.1 (1.0-1.9). The mean RCA was 179.6 ± 8.3° (normalized RCA: 49.9 ± 2.3%) and the mean OCA was 24.6 ± 3.7°. The indexes had a high-grade of inter-observer and intra-observer reliability for each of the four observers. Significantly higher values were found for males for TDI, ACI, PCI and RCA. CONCLUSION: The novel radiological parameters described are simple, reliable and easily reproducible. These features make them a promising tool for radiographic evaluation both for orthopaedic surgeons and for radiologists in the emergency department setting or during outpatient services. LEVEL OF EVIDENCE: Basic Science Study (Case Series). CLINICAL RELEVANCE: The novel radiological parameters described are reliable, easily reproducible and become handy for orthopaedic surgeons as well as radiologists in daily clinical practice.

Validation of a new topographic classification of bone marrow lesions in the knee: the six-letter system.

PURPOSE: The aim of this study was to propose and validate a new six-item topographical classification of knee bone marrow lesions in coronal MRI images, to provide an easy-to-use aid to describe their location in a more reproducible and accurate way. METHODS: This study was conducted in four phases. The first was to do a literature search for methods of describing bone marrow lesions in MRI of the knee. The second was creation of a six-area topographic classification of bone marrow lesions in coronal MRI of the knee. The third phase was selection of cases with bone marrow lesions on knee MRI performed in a single hospital between January of 2017 and December of 2018. The fourth phase was categorization of the bone marrow lesions' location according to the new proposed classification by three independent examiners, two orthopedic surgeons and one radiologist. Patient's demographic data and associated lesions were collected. The inter-observer and intra-observer reliability of the proposed classification was then calculated. RESULTS: MRI examination of 4000 patients were studied and in 520 patients a total of 666 bone marrow lesions were identified and their location classified using the new system. The inter-observer and intra-observer reliability analysis found a Fleiss' Kappa value of 0.96 (0.95-0.97) and 0.97 (0.96-0.97), respectively, confirming the high reproducibility of the proposed classification. CONCLUSIONS: The proposed six-location classification of bone marrow lesions is highly reproducible and can help researchers develop studies and share information in a more accurate and reliable way. The correct classification of bone marrow lesions can lead to a more accurate description of this pathology and help clinicians to propose appropriate therapies for this group of patients. LEVEL OF EVIDENCE: V.

Multicentric, multifocal, and recurrent osteoid osteoma of the hip: first case report.

BACKGROUND: Osteoid osteoma is a benign bone-forming tumour, which very unfrequently has multifocal or multicentric presentation. We report the first known case of a multicentric, multifocal and recurrent osteoid osteoma treated using radiofrequency ablation. CASE PRESENTATION: A 39-year-old man with two-year history of left hip pain was admitted at our Institution. The pain was more intense during the night and partially relieved by salicylates. Pelvis CT demonstrated two lytic lesions (8 and 7 mm, respectively) with surrounding sclerotic reactive bone, both with a central focal area of high attenuation, located in the femoral neck and along the anterior portion of the acetabulum, respectively. Both lesions had clinical and imaging findings consistent with multicentric osteoid osteoma. Thus, the two lesions were biopsied - with pathologic confirmation of osteoid osteoma - and treated using radiofrequency ablation. Hip pain decreased but did not disappear, actually increasing a few months after treatment. CT and MRI were performed showing a smaller lesion (5 mm) with the same imaging features, surrounded by marrow oedema, along the posterior column of the acetabulum. The lesion was considered suspicious for osteoid osteoma, overlooked on previous examinations. Therefore, a diagnosis of multicentric and multifocal osteoid osteoma was established. The new lesion was again treated with radiofrequency ablation with symptom disappearance. However, hip pain relapsed after 18 months, and CT and MRI showed an osteoid osteoma recurrence on the posterior column of the acetabulum, which was biopsied and successfully treated using radiofrequency ablation. CONCLUSIONS: To our knowledge, this is the first reported case of multicentric, multifocal, recurrent osteoid osteoma. Our case report highlights the importance of considering a diagnosis of multifocal osteoid osteoma when dealing with multifocal lytic lesions of the bone and with pain persistence after treatment. It also emphasises the combined role of CT and MRI in this setting.

Radiologist-rheumatologist multidisciplinary approach in the management of axial spondyloarthritis: a Delphi consensus statement.

OBJECTIVES: The aim of this study was to develop a Delphi consensus statement between rheumatologists and radiologists for the diagnosis and monitoring of axial spondyloarthritis (axial-SpA). METHODS: Following an extensive literature search to identify unmet needs and potential goals for a multidisciplinary approach, a scientific board comprising 28 Italian hospital-based rheumatologists (n=19) and radiologists (n=9) identified 8 "starting points", resulting in the development of 23 consensus statements covering issues from current practice guidelines to specific MRI protocols for the assessment of axial-SpA. Each participant anonymously expressed a level of agreement for each statement using a 5-point Likert scale (1="strongly disagree"; 5="strongly agree") via an online Delphi method.Total cumulative agreement (TCA) was defined as the sum of the percentage of response to items 4 ("agree") and 5 ("absolutely agree"). Consensus was defined as ≥80% total cumulative agreement for each statement. RESULTS: After the first round of voting (28 participants), positive consensus was reached for 28/31 (90.3%) statements. Statements without consensus (n=3) were discussed in a face-to-face plenary session prior to the second vote (28 participants). After the second round voting, positive consensus was attained for all 31 statements, with mean final TCA of 95.5% (range 82.1-100%). CONCLUSIONS: This Delphi consensus statement provides an aid to rheumatologists and radiologists for the diagnosis and monitoring of axial-SpA.

Effects of the Intraneural and Subparaneural Ultrasound-Guided Popliteal Sciatic Nerve Block: A Prospective, Randomized, Double-Blind Clinical and Electrophysiological Comparison.

BACKGROUND AND OBJECTIVES: This prospective, randomized, double-blind study compared the effects of the ultrasound-guided popliteal sciatic nerve block performed by either intraneural or subparaneural approach followed by an electrophysiological evaluation. We hypothesized that intraneural injection provides a faster onset with a better success rate compared with the subparaneural approach. METHODS: Eighty-eight patients were enrolled and randomized to receive an ultrasound-guided popliteal sciatic nerve block injecting 15 mL ropivacaine 1% according to an intraneural injection (group INTRA = 44) or a subparaneural injection (group SUBPARA = 44). The primary end point was the onset time of sensory and motor block, whereas secondary end points were successful, duration of the block, and the variation of the electrophysiological assessment after 5 weeks. The study was registered prior to patient enrollment (clinicaltrials.gov identifier NCT01987128). RESULTS: The median onset time for successful sciatic nerve block in the INTRA group was 10 (5-15 [5-30]) minutes versus 25 (15-35 [5-45]) minutes in the SUBPARA group (P < 0.001), with a rate of 41/43 (95.3%) compared with 25/40 (62.5%) in the SUBPARA group (P < 0.001). No difference was found regardless of the duration of the block. Fifty-three patients also performed the electrophysiological assessment at 5 weeks, showing a subclinical, significant reduction in amplitude of the action potentials with no difference between groups. No patients reported any clinical neurological complications after 6 months. CONCLUSIONS: In ultrasound-guided popliteal sciatic nerve block, intraneural injection provided a faster onset and better success rate compared with subparaneural. Both techniques resulted in a similar subclinical reduction in amplitude of the sciatic action potentials at 5 weeks after surgery. These findings should not be extended to other approaches.

Case report: calcific tendinitis of the rectus femoris: a rare cause of snapping hip.

BACKGROUND: Internal snapping hip is a syndrome caused by recurrent subluxation of the iliopsoas tendon. There is little agreement regarding the impinging sites responsible for the jerky motion of the tendon. Thus far, the lesser trochanter, anterior capsule, and iliopectineal eminence are considered the most likely catching sites. CASE DESCRIPTION: We report an unusual case in which a calcific tendinitis of the rectus femoris direct head impinged against the overlying iliacus muscle, resulting in a painful coxa saltans. The exclusive involvement of the direct head hid the calcium deposit on standard radiographs, whereas MRI suggested but poorly showed the tendon disease. Dynamic ultrasonography and CT scanning allowed a precise diagnosis and subsequent treatment with CT-guided steroid injection. LITERATURE REVIEW: Calcific tendinitis of the rectus anterior direct head has not been reported as a possible cause of snapping hip; involvement of the direct head in rectus anterior calcific tendinitis was described in one case. PURPOSES AND CLINICAL RELEVANCE: Our case shows the rectus anterior direct head may be involved in the etiology of coxa saltans. Theoretically any thickening of the tendon might activate the same pathomechanism. Physicians should consider this possible new cause of internal snapping hip when the most common ones have been excluded, especially as it may be managed easily with steroid injection.

The role of diagnostic imaging in synovial sarcoma. Our experience.

PURPOSE: Synovial sarcoma is a rare malignant mesenchymal tumour of soft tissues. It accounts for 8-10% of all soft-tissue sarcomas. The clinical symptoms at onset are often subtle and the course of the disease is slow. Therefore, diagnostic imaging is essential for the early diagnosis of a malignant tumoral lesion. The aim of this study was to assess the role and usefulness of the different imaging procedures in the diagnosis of synovial sarcoma and to present their findings. MATERIALS AND METHODS: Between 1985 and 2002, we retrospectively reviewed 35 patients (21 men and 14 women, aged 14-66 years) with synovial sarcoma treated in the Orthopaedic Oncological Surgery Division of our hospital. All patients had previously undergone conventional radiography, B-mode ultrasound, computed tomography and magnetic resonance imaging. RESULTS: Conventional radiography showed indirect signs of the neoplasm including soft-tissue swelling, calcifications and bone erosions. Ultrasound allowed the detection of focal nodular lesions but was non-specific in distinguishing malignant features. CT after intravenous injection of contrast medium demonstrated inhomogeneous enhancement in 90% of cases, suggesting an alteration in tumour microcirculation. In all cases examined, MRI enabled detection of the intrinsic structural alterations of the mass indicative of an aggressive lesion. CONCLUSIONS: Contrast-enhanced CT and MRI provide useful information on the intrinsic structure of the neoplasm, suggesting a presumptive diagnosis. Furthermore, they are necessary for tumour staging, surgical planning and follow-up. The definitive diagnosis is provided by biopsy and histology.