Anatomical study of the medial calcaneal nerve using high-resolution ultrasound

OBJECTIVES

To determine whether high-resolution ultrasound (US) can identify the course and relations of the medial calcaneal nerve (MCN).

METHODS

This investigation was initially undertaken in eight cadaveric specimens and followed by a high-resolution US study in 20 healthy adult volunteers (40 nerves) by two musculoskeletal radiologists in consensus. The location and course of the MCN as well as its relationship to adjacent anatomical structures were evaluated.

RESULTS

The MCN was consistently identified by US along its entire course. The mean cross-sectional area of the nerve was 1 mm2 (range 0.5-2). The level at which the MCN branched from the tibial nerve was variable, located a mean of 7 mm (range - 7-60) proximal to the tip of the medial malleolus. At the level of the medial retromalleolar fossa, the MCN was located inside the proximal tarsal tunnel a mean of 8 mm (range 0-16) posterior to the medial malleolus. More distally, the nerve was depicted in the subcutaneous tissue at the surface of the abductor hallucis fascia with a mean direct distance to the fascia of 1.5 mm (range 0.4-2.8).

CONCLUSIONS

High-resolution US can identify the MCN at the level of the medial retromalleolar fossa, as well as more distally in the subcutaneous tissue at the surface of the abductor hallucis fascia. In the setting of heel pain, precise sonographic mapping of the MCN course may enable the radiologist to make diagnosis of nerve compression or neuroma, and perform selective US-guided treatments.

CLINICAL RELEVANCE STATEMENT

In the setting of heel pain, sonography is an attractive tool for diagnosing compression neuropathy or neuroma of the medial calcaneal nerve, and enables the radiologist to perform selective image-guided treatments such as diagnostic blocks and injections.

KEY POINTS

• The MCN is a small cutaneous nerve which rises from the tibial nerve in the medial retromalleolar fossa to the medial side of the heel. • The MCN can be depicted by high-resolution ultrasound along its entire course. • In the setting of heel pain, precise sonographic mapping of the MCN course may enable the radiologist to make diagnosis of neuroma or nerve entrapment, and perform selective ultrasound-guided treatments such as steroid injection or tarsal tunnel release.

Ultrasound and MR imaging of peripheral nerve tumors: the state of the art

Peripheral nerve sheath tumors are a heterogeneous subgroup of soft tissue tumors that either arise from a peripheral nerve or show nerve sheath differentiation. On imaging, direct continuity with a neural structure or location along a typical nerve distribution represents the most important signs to suggest the diagnosis. Ultrasound and magnetic resonance imaging are the best modalities to evaluate these lesions. First, it is necessary to differentiate between a true tumor and a non-neoplastic nerve condition such as a neuroma, peripheral nerve ganglion, intraneural venous malformation, lipomatosis of nerve, or nerve focal hypertrophy. Then, with a combination of clinical features, conventional and advanced imaging appearances, it is usually possible to characterize neurogenic tumors confidently. This article reviews the features of benign and malignant peripheral nerve sheath tumors, including the rare and recently described tumor types. Furthermore, other malignant neoplasms of peripheral nerves as well as non-neoplastic conditions than can mimick neurogenic tumor are herein discussed.

Shoulder palsy following SARS‐CoV2 infection: 2 cases of typical Parsonage‐Turner syndrome

Background and purpose

Coronavirus disease 2019 (COVID‐19) is now known to cause neurological complications in both the central and the peripheral nervous system. Two new cases of typical neuralgic amyotrophy or Parsonage–Turner (PT) syndrome following coronavirus 2 infection (SARS‐CoV‐2) are reported here with explicit electrophysiological and imaging pathological features, underlining the possible association between COVID‐19 and PT syndrome.

Case reports

Case 1 was a 45‐year‐old schoolteacher presenting with acute pain in the right shoulder a few days after SARS‐CoV‐2 infection, with shoulder abduction and elbow flexion weakness. Needle electromyography showed a decrease in motor unit recruitment in the biceps brachii, and plexus magnetic resonance imaging (MRI) revealed a hyperintense signal involving the right C6 root and the superior truncus of the brachial plexus. Case 2 was a 21‐year‐old man hospitalized for dyspnea secondary to SARS‐CoV‐2 infection. Ten days after symptom onset, he presented right shoulder pain with difficulty in raising his right arm, revealing an isolated deficit of the serratus major muscle with a right scapula winging. Electrophysiological evaluation exhibited an isolated involvement of the long thoracic nerve with a neurogenic recruitment pattern in the serratus major muscle. Plexus MRI displayed a thickening and hyperintense signal involving the right long thoracic nerve.

Discussion

Parsonage–Turner syndrome triggered by SARS‐CoV‐2 seems to present clinical, electrophysiological and MRI characteristics similar to classic para‐infectious PT syndrome, including the time frame between viral infection and neurological symptom onset.

Conclusion

SARS‐CoV‐2 might be a new infectious trigger of PT syndrome.

Ultrasound-Guided Perimeniscal Injections: Anatomical Description and Feasibility Study

OBJECTIVES

To anatomically describe the ultrasound (US)-guided perimeniscal injection technique, and evaluate its feasibility in the treatment of meniscal pain.

METHODS

This work was initially undertaken in four cadaveric specimens with US-guided medial and lateral perimeniscal injection of China ink, followed by cadaveric dissection to assess injectate distribution, and potential injury to intra-articular and peri-articular structures. Then, 35 consecutive patients who underwent US-guided perimeniscal corticosteroid injection under local anesthesia for the treatment of symptomatic medial (30/35) or lateral (5/35) degenerative meniscal tear were retrospectively evaluated. Clinical outcome was assessed using a 0-10 numerical verbal rating scale (VRS) to evaluate severity of pain before, during, and after procedure at 6 weeks follow-up.

RESULTS

Seven of eight (87.5%) ex vivo injections were accurate. A single inaccurate medial perimeniscal injection infiltrated the tibial collateral ligament instead of the perimeniscal area. No anatomical specimen exhibited intrameniscal injection or injury to regional structures. All procedures (35/35) performed clinically were technically successful. Median VRS scores were: 7 (range, 3-9) before procedure, 5 (range, 0-10) during procedure, and 1.5 (range, 0-9) after procedure at 6 weeks follow-up (P <.0001). No complication was observed.

CONCLUSIONS

US-guided perimeniscal injections can accurately and safely deliver injectates in the perimeniscal area. In addition, our data suggest that perimeniscal corticosteroid injection provides significant symptom relief at 6 weeks in patients with meniscal pain. Further studies with long-term follow-up will be required to evaluate the role of perimeniscal injections in the nonoperative management of meniscal pathology.

Osteoid Osteoma: Percutaneous CT-guided Cryoablation Is a Safe, Effective, and Durable Treatment Option in Adults

Background Cryoablation is playing an increasing role in the percutaneous treatment of bone tumors. However, despite its potential advantages over heat-based ablation techniques, the clinical safety and efficacy of cryoablation have not been established for osteoid osteoma treatment. Purpose To evaluate percutaneous CT-guided cryoablation for the treatment of osteoid osteoma in young patients and adults. Materials and Methods This retrospective study reviewed data from 50 consecutive patients who underwent percutaneous CT-guided cryoablation for the treatment of osteoid osteoma between January 2013 and June 2019 in a single institution. In 30 of 50 patients (60%), the procedure was carried out with the patient under local anesthesia and conscious sedation, with the cryoprobe covering the lesion from an extraosseous position, avoiding direct penetration of the nidus. Clinical and radiologic features, procedure-related data, visual analog scale (VAS) pain scores, complications, and overall success rate were evaluated. Statistical analyses were performed by using the nonparametric Friedman test and Wilcoxon signed rank test for repeated measures. Results Fifty patients (median age, 24 years; interquartile range [IQR], 19-38 years; 31 men) underwent CT-guided cryoablation for the treatment of osteoid osteoma, with a 96% (48 of 50 patients) overall clinical success rate. Of the two patients without clinical success, one patient had incomplete pain relief and the other experienced a recurrence of osteoid osteoma at 11 months, which was successfully treated with a second cryoablation procedure. The median VAS pain score was 8 (IQR, 7-8) before the procedure and 0 (IQR, 0-1; P < .001) after the procedure at both primary (6 weeks) and secondary (18-90 months) follow-up. Three of the 50 patients had minor complications (6%); no major complications were reported. Conclusion Osteoid osteoma was safely, effectively, and durably treated with CT-guided percutaneous cryoablation. In the majority of patients, treatment could be performed without general anesthesia, with the cryosphere covering the nidus from an extraosseous position. © RSNA, 2021.

Intradiscal oxygen-ozone therapy for the treatment of symptomatic lumbar disc herniation: A preliminary study

PURPOSE

To assess safety and effectiveness of computed tomography (CT)-guided intradiscal oxygen-ozone therapy (O₂-O₃ therapy) for the treatment of symptomatic lumbar disc herniation and radiological changes.

MATERIALS AND METHODS

This study was conducted in twenty patients presenting lumbar disc herniation with resistant lumbar or lumbar radicular pain They underwent intradiscal oxygen-ozone therapy under CT guidance. They were treated at one- or two-disc levels, representing a total of 24 discs treated. MR imaging examinations were obtained before treatment and 2 months post-procedure to analyse treatment-related disc modifications including modification of the surfaces of the disc and of the herniated disc, and the variations in disc height according to the disc height index. Clinical outcomes were assessed using the visual analogue scale (VAS) to evaluate the severity of pain before the procedure, at primary (2 months) and at secondary (12 months) follow-ups.

RESULTS

All the procedures were technically successful. The median VAS scores were 7.95 before the procedure, 3.9 at 2 months and 2.95 at 12 months. MRI analysis showed a significant decrease in herniation size at 2 months (-20%, p = 0.008). No immediate or late complications were observed. Only three patients (13.6%) underwent lumbar spine microdiscectomy in the year following ozone therapy. The treatment appeared to be more effective in cases of nerve root symptomatology.

CONCLUSION

This study suggests that intradiscal O₂-O₃ therapy is safe and effective for the treatment of lumbar disc herniation associated with resistant lumbar or lumbar radicular pain.

Stenosing tenosynovitis of the extensor digitorum tendons of the hand: clinical and sonographic features

OBJECTIVE

To describe the ultrasound (US) features of 18 patients with extensor digitorum communis stenosing tenosynovitis (EDCST).

MATERIALS AND METHODS

A retrospective search in the radiologic information systems of two separate Institutions was performed to identify all patients presenting EDCST between January 2010 and September 2019. A total of 18 patients (ten males and eight females; mean age, 57.4 years) were identified and included. Sonographic examinations were retrospectively reviewed by two senior radiologists to assess morphologic changes and power Doppler activity of the extensor retinaculum (ER) and of the extensor digitorum communis (EDC) tendons and sheath. The presence of dynamic impingement between the EDC and the ER was evaluated using video clip records.

RESULTS

At the ultrasound, all patients (18/18; 100%) presented thickening of both the ER and EDC tendons associated with EDC tendon sheath effusion. Power Doppler hyperemia of the ER was inconstant and observed in 11 cases (11/18; 61.1%) as tendon sheath effusion observed in 16 cases (16/18; 88.9%). A cyst located inside the EDC of the index finger was observed in three of these patients (3/18; 17%). Dynamic examination showed impingement of the EDC against the ER during active tendon extension in all patients (18/18; 100%). Four of these patients (4/18; 22%) underwent surgery allowing diagnosis confirmation and release of EDCST, while the remaining fourteen patients (14/18; 78%) were either treated conservatively or using US-guided steroid injection.

CONCLUSION

US findings of EDCST include thickening of the ER and EDC tendons, EDC tendon sheath effusion, and in some cases presence of an EDC intratendinous cyst. Impingement of the EDC tendons against the ER is well demonstrated using dynamic US.

Flat-panel CT arthrography for cartilage defect detection in the ankle joint: first results in vivo

OBJECTIVES

The purpose of this study was to compare the diagnostic performance of flat-panel computed tomography (FPCT) arthrography for cartilage defect detection in the ankle joint to direct magnetic resonance (MR) arthrography using multidetector computed tomography (MDCT) arthrography as the reference standard.

METHODS

Twenty-seven patients with specific suspicion of articular cartilage lesion underwent ankle arthrography with injection of a mixture of diluted gadolinium and iobitridol and were examined consecutively with the use of FPCT, MDCT, and 1.5 T MR imaging. FPCT, MDCT, and MR arthrography examinations were blinded and randomly evaluated by two musculoskeletal radiologists in consensus. In each ankle, eight articular cartilage areas were assessed separately: medial talar surface, medial talar trochlea, lateral talar trochlea, lateral talar surface, tibial malleolus, medial tibial plafond, lateral tibial plafond, and fibular malleolus. Findings at FPCT and MR were compared with MDCT assessments in 216 cartilage areas.

RESULTS

For the detection of cartilage defects, FPCT demonstrated a sensitivity of 97%, specificity of 95%, and accuracy of 96%; and MR arthrography showed a sensitivity of 69%, specificity of 94%, and accuracy of 87%. FPCT and MR arthrography presented almost perfect agreement (κ = 0.87) and moderate agreement (κ = 0.60), respectively, with MDCT arthrography. Mean diagnostic confidence was higher for FPCT (2.9/3) than for MR (2.3/3) and MDCT (2.7/3) arthrography.

CONCLUSIONS

FPCT demonstrated better accuracy than did 1.5 T MR arthrography for cartilage defect detection in the ankle joint. Therefore, FPCT should be considered in patients scheduled for dedicated imaging of ankle articular cartilage.

Estimation of joint contact pressure in the index finger using a hybrid finite element musculoskeletal approach

The knowledge of local stress distribution in hand joints is crucial to understand injuries and osteoarthritis occurrence. However, determining cartilage contact stresses remains a challenge, requiring numerical models including both accurate anatomical components and realistic tendon force actuation. Contact forces in finger joints have frequently been calculated but little data is available on joint contact pressures. This study aimed to develop and assess a hybrid biomechanical model of the index finger to estimate in-vivo joint contact pressure during a static maximal strength pinch grip task. A finite element model including bones, cartilage, tendons, and ligaments was developed, with tendon force transmission based on a tendon-pulley system. This model was driven by realistic tendon forces estimated from a musculoskeletal model and motion capture data for six subjects. The hybrid model outputs agreed well with the experimental measurement of fingertip forces and literature data on the physiological distribution of tendon forces through the index finger. Mean contact pressures were 6.9 ± 2.7 MPa, 6.2 ± 1.0 MPa and 7.2 ± 1.3 MPa for distal, proximal interphalangeal and metacarpophalangeal joints, respectively. Two subjects had higher mean contact pressure in the distal joint than in the other two joints, suggesting a mechanical cause for the prevalence of osteoarthritis in the index distal joint. The inter-subject variability in joint contact pressure could be explained by different neuromuscular strategies employed for the task. This first application of an effective hybrid model to the index finger is promising for estimating hand joint stresses under daily grip tasks and simulating surgical procedures.

Anterolateral knee pain related to thrombosed lateral patellar retinaculum veins: Unusual anterolateral pain of the knee

We describe the ultrasound (US) features of venous thrombosis involving the lateral patellar retinaculum (LPR) veins presenting as anterolateral knee pain. Four male patients, aged 16 to 35 years, were referred for lateropatellar pain with focal tenderness. In two cases, physical examination also demonstrated soft tissue swelling at the anterolateral aspect of the knee. In all four cases, US showed subcutaneous fat edema surrounding a thrombosis involving the LPR veins. Magnetic resonance imaging performed before US in one patient revealed only nonspecific subcutaneous fat edema and was therefore unable to make the correct diagnosis of LPR venous thrombosis.

Comparison of MRI and motor evoked potential with triple stimulation technique for the detection of brachial plexus abnormalities in multifocal motor neuropathy

BACKGROUND

Conduction blocks (CB) are the diagnostic hallmark of multifocal motor neuropathy (MMN). Conventional nerve conduction studies cannot detect CB above Erb's point. Our purpose was to compare the performance of the motor evoked potential with triple stimulation technique (MEP-TST) and MRI in the detection of abnormalities of the brachial plexus.

METHODS

Examinations were performed on 26 patients with MMN (11 definite, 6 probable, 9 possible), of whom 7 had no CB.

RESULTS

MEP-TST detected proximal CB in 19/26 patients. Plexus MRI showed T2 hyperintensity in 18/26 patients, with nerve enlargement in 14/18. A combination of both techniques increased the detection rate of brachial plexus abnormalities to 96% of patients (25/26).

CONCLUSIONS

MEP-TST and MRI have high sensitivities for detecting brachial plexus abnormalities. A combination of the two techniques increases the detection rate of supportive criteria for the diagnosis of MMN.

The lateral patellar retinaculum defect: anatomical study using ultrasound

OBJECTIVE

The purpose of this study was to evaluate whether ultrasound allows precise assessment of a focal defect at the lateral patellar retinaculum (LPR) and to determine its anatomical significance.

MATERIALS AND METHODS

This work was initially undertaken in four cadaveric specimens and followed by high-resolution ultrasound study in 48 healthy adult volunteers (96 knees) by two musculoskeletal radiologists. Dimension and location of the LPR defect and its relations to adjacent anatomical structures were analyzed.

RESULTS

A focal defect of the LPR through which vessels penetrated was constantly identified by ultrasound in our population. The mean transverse diameter of the defect was 2.4 mm (range, 1-6 mm). The defect was located a mean of 23.7 mm (range, 18-30 mm) proximal to the lateral tibial plateau and 6.6 mm (range, 4-9 mm) lateral to the patellar tendon. Anatomical dissection demonstrated that the LPR defect is related to perforating vessels that originate from the peripatellar anastomotic ring.

CONCLUSIONS

The focal defect of the LPR can be depicted by ultrasonography. Reproducible anatomical landmarks for its detection could be defined. Our data suggest the LPR defect may be considered a normal variant rather than a pathologic change.

Soft Tissue Masses of the Knee Related to a Focal Defect of the Lateral Patellar Retinaculum

We report on the imaging features of 6 soft tissue masses in the anterolateral aspect of the knee related to a focal defect of the lateral patellar retinaculum. In 4 patients (3 female and 1 male; 6-65 years) presenting with nontender palpable soft tissue masses in the anterolateral aspect of their knees, ultrasonography showed a focal defect of the lateral patellar retinaculum with herniation of the Hoffa fat pad, which was only visible in flexion. A magnetic resonance imaging examination performed in 1 case confirmed the defect in the lateral patellar retinaculum but did not show a mass, as the knee was examined only at 10° of flexion. The 2 remaining patients (one male and 1 female; 62 and 55 years) presented with soft tissue masses in their anterolateral knees in both flexion and extension. These masses were related respectively to a lipoma of the Hoffa fat pad and to a ganglion cyst, both herniated through a defect of the lateral patellar retinaculum. Our cases suggest that a focal defect of the lateral patellar retinaculum may be a route for Hoffa fat pad herniation as well as a route for superficial extension of infrapatellar fat lesions such as lipomas and ganglion cysts.

Design and properties of a novel radiopaque injectable apatitic calcium phosphate cement, suitable for image-guided implantation

An injectable purely apatitic calcium phosphate cement (CPC) was successfully combined to a water-soluble radiopaque agent (i.e., Xenetix^® ), to result in an optimized composition that was found to be as satisfactory as poly(methyl methacrylate) (PMMA) formulations used for vertebroplasty, in terms of radiopacity, texture and injectability. For that purpose, the Xenetix dosage in the cement paste was optimized by injection of the radiopaque CPC in human cadaveric vertebrae under classical PMMA vertebroplasty conditions, performed by interventional radiologists familiar with this surgical procedure. When present in the cement paste up to 70 mg I mL^-1 , Xenetix did not influence the injectability, cohesion, and setting time of the resulting composite. After hardening of the material, the same observation was made regarding the microstructure, mechanical strength and alpha-tricalcium phosphate to calcium deficient apatite transformation rate. Upon implantation in bone in a small animal model (rat), the biocompatibility of the Xenetix-containing CPC was evidenced. Moreover, an almost quantitative release of the contrast agent was found to occur rapidly, on the basis of in vitro static and dynamic quantitative studies simulating in vivo implantation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2786-2795, 2018.

A dynamic study of the anterior cruciate ligament of the knee using an open MRI

Recent anatomical and radiological studies of the anterior cruciate ligament (ACL) suggest the ACL length and orientation change during knee flexion, and an open MRI sequencing during knee flexion enables a dynamic ACL analysis. This study's goal is to describe a normal ACL using a 1T open MRI and, in particular, variations in length and insertion angles at different degrees of flexion. Twenty-one volunteers with clinically healthy knees received a dynamic MRI with their knees in hyperextension, neutral position, and flexed at 45° and 90° angles. For each position, two radiologists measured the ACL lengths and angles of the proximal insertion between the ACL's anterior edge and the roof of the inter-condylar notch. Additionally, we measured the ACL's and the tibial plateau's distal angle insertion between their anterior edges and then compared these with the nonparametric Wilcoxon test. The ACL had a significant extension between the 90° flexion and all other positions (hyperextension: 31.75 ± 2.5 mm, neutral position: 32.5 ± 2.6 mm, 45°: 35.6 ± 1.6 mm, 90°: 35.6 ± 1.6 mm). There was also a significant increase of the angle insertion between the proximal 90° flexion and all other positions, as well as between hyperextension and bending to 45° (hyperextension: 2.45° ± 3.7°, neutral: 13.4° ± 9.7°, 45°: 33 25 ± 9.3, 90: 51.85° ± 9.3°). Additionally, there is a significant increase in the distal angle insertion for all positions (hyperextension: 133.2° ± 5.4°, neutral position: 134.95° ± 4.4°, 45°: 138.35° ± 5.9°, 90°: 149.15° ± 8.6°). Our study is the first to exhibit that a dynamic MRI has a significant ACL extension in vivo during bending. This concept opens the way for further studies to improve the diagnosis of traumatic ACL injuries using a dynamic MRI.

Anatomy of the proximal femur at the time of total hip arthroplasty is a matter of morphotype and etiology but not gender

This study aimed to determine (1) whether: gender, morphotype, or etiology are correlated with the shape of the proximal femur in patients with advanced hip osteoarthritis and (2) is there any clinical predictive factors of potential abnormal anatomy of the hip at the time of total hip arthroplasty (THA)? We reviewed 689 European hips of patients who underwent THA for primary osteoarthritis (OA) or avascular necrosis (AVN), between 2000 and 2005. The patients were stratified according to their (1) Morphotype, (2) Gender, and (3) Etiology for undergoing THA. Two independent observers measured the following four anatomical parameters on preoperative CT-scans: neck shaft angle (NSA) and femoral neck version, femoral offset and lower-limb torsion. Our results showed that both morphotype and etiology, but not gender or body mass index, were correlated with femoral anatomical parameters. Two types of patients were identified as "at risk" for abnormal hip anatomy: (1) AVN-Endomorphic patients (2) OA-Ectomorphic patients. Etiology of the advanced hip osteoarthritis and patients' morphotype may predict the proximal femur anatomy at the time of THA.

Anterior shoulder instability: the role of advanced shoulder imaging in preoperative planning

Despite advances in the understanding of anterior shoulder instability, recurrence rates after arthroscopic and open surgery have been reported to be as high as 30%. A successful operative outcome for patients with anterior shoulder instability requires the surgeon to perform a complete preoperative evaluation based on a thorough physical examination and advanced imaging techniques. In addition to the Bankart lesion, the treating surgeon must be aware of other copathologies, such as bony lesions of the glenoid or humeral head, humeral avulsion of the glenohumeral ligament, and articular cartilage defects that can occur in concert with capsular pathology and may necessitate a change in surgical strategy. This article focuses specifically on the osseous, labroligamentous, cartilage, and rotator cuff lesions demonstrated on preoperative imaging that are important to recognize in the preoperative work-up to optimize surgical outcomes for anterior instability.

Does surface roughness influence the primary stability of acetabular cups? A numerical and experimental biomechanical evaluation

Most acetabular cups implanted today are press-fit impacted cementless. Anchorage begins with the primary stability given by insertion of a slightly oversized cup. This primary stability is key to obtaining bone ingrowth and secondary stability. We tested the hypothesis that primary stability of the cup is related to surface roughness of the implant, using both an experimental and a numerical models to analyze how three levels of surface roughness (micro, macro and combined) affect the primary stability of the cup. We also investigated the effect of differences in diameter between the cup and its substrate, and of insertion force, on the cups' primary stability. The results of our study show that primary stability depends on the surface roughness of the cup. The presence of macro-roughness on the peripheral ring is found to decrease primary stability; there was excessive abrasion of the substrate, damaging it and leading to poor primary stability. Numerical modeling indicates that oversizing the cup compared to its substrate has an impact on primary stability, as has insertion force.

Splenic sarcoidosis mimicking neoplastic disease

Sarcoidosis is a multisystem granulomatous disease of unknown cause that commonly involves the spleen. Sarcoid can produce either homogeneous splenomegaly or multiple splenic nodules. Although other organ system involvement usually occurs, this is not invariable. Herein, we report on the clinical, histological, and radiological features-including sonography and MRI-of an isolated splenic sarcoidosis that mimicked neoplastic disease in a 37-year-old female. Knowledge of this atypical sonographic presentation may prevent unnecessary splenectomy.

Rotation in total knee arthroplasty: no difference between patient-specific and conventional instrumentation

PURPOSE

It was our hypothesis that patient-specific instrumentation (PSI) can improve the accuracy of the rotational alignment in TKA based on the concept of the system and on the potential to clearly identify pre-operatively during planning the classical anatomical landmarks that serve as references to set-up the rotation both for the femur and tibia.

MATERIALS AND METHODS

In this prospective comparative randomized study, 40 patients (20 in each group) operated in our institution between September 2012 and January 2013 by the 2 senior authors were included. Randomization of patients into one of the two groups was done by the Hospital Informatics Department with the use of a systematic sampling method. All patients received the same cemented high-flex mobile bearing TKA. In the PSI group, implant position was compared to the planed position using previously validated dedicated software. The position of the implants (frontal and sagittal) was compared in the 2 groups on standard X-rays, and the rotational position was analysed on post-operative CT-scan.

RESULTS

90 % of the patients add <2° or mm of difference between the planned position of the implants and the obtained position, except for the tibial rotation where the variations were much higher. Mean HKA was 179° (171-185) in the PSI group with 4 outliers (2 varus: 171° and 172°:184° and 185°) and 178.3° with 2 outliers (171° and 176°) in the control group. No difference was observed between the two groups concerning the frontal and sagittal position of the implants on the ML and AP X-rays. No significant difference of femoral rotation was observed between the two groups with a mean of 0.4° in the PSI group and 0.2° in the control group (p: n.s). Mean tibial rotation was 8° of internal rotation in the PSI group and 15° of internal rotation in the standard group (p: n.s).

CONCLUSION

Based on our results, we were unable to confirm our hypothesis as PSI cannot improve rotation in TKA. More work needs to be done to more clearly define the place of PSI in TKA, to keep on improving the accuracy of the system and to better define the individual targets in TKA in terms of frontal, sagittal and rotational positioning of the implant for each patient.

LEVEL OF EVIDENCE

Prospective comparative randomized study, Level II.

Treatment of symptomatic para-articular intraosseous cysts by percutaneous injection of bone cement

PURPOSE

To describe the technique and clinical outcome of percutaneous injection of bone cement in the treatment of symptomatic para-articular intraosseous cysts.

MATERIALS AND METHODS

Five patients (three men, two women; mean age 35 years) with painful para-articular intraosseous cysts were treated by percutaneous injection of bone cement under combined fluoroscopic and computed tomography (CT) guidance. The lesions were all located in weight-bearing bones, involving the acetabulum, proximal tibia, distal tibia, talus, and calcaneus, respectively.

RESULTS

The average amount of bone cement injected was 2.1 ml (range, 0.6-3.5 ml). Calcium phosphate cement was used in four cases and acrylic cement in one case. There were no immediate or delayed complications. Full pain relief was obtained between 1 and 4 weeks after treatment. All patients made a complete recovery and were pain-free at their last visit.

CONCLUSIONS

Percutaneous injection of bone cement was a safe and efficient technique in the management of symptomatic para-articular intraosseous cysts in our population.

Bone texture analysis is correlated with three-dimensional microarchitecture and mechanical properties of trabecular bone in osteoporotic femurs

Fracture of the proximal femur is a major public health problem in elderly persons. It has recently been suggested that combining texture analysis and bone mineral density measurement improves the failure load prediction in human femurs. In this study, we aimed to compare bone texture analysis with three-dimensional (3D) microarchitecture and mechanical properties of trabecular bone in osteoporotic femurs. Eight femoral heads from osteoporotic patients who fractured their femoral neck provided 31 bone cores. Bone samples were studied using a new high-resolution digital X-ray device (BMA™, D3A Medical Systems) allowing for texture analysis with fractal parameter H (mean), and were examined using micro-computed tomography (microCT) for 3D microarchitecture. Finally, uniaxial compression tests to failure were performed to estimate failure load and apparent modulus of bone samples. The fractal parameter H (mean) was strongly correlated with bone volume fraction (BV/TV) (r = 0.84) and trabecular thickness (Tb.Th) (r = 0.91) (p < 0.01). H (mean) was also markedly correlated with failure load (r = 0.84) and apparent modulus (r = 0.71) of core samples (p < 0.01). Bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) demonstrated significant correlations with failure load (r = 0.85 and 0.72, respectively) and apparent modulus (r = 0.72 and 0.64, respectively) (p < 0.01). Overall, the best predictors of failure load were H (mean), bone volume fraction, and trabecular thickness, with r (2) coefficients of 0.83, 0.76, and 0.80 respectively. This study shows that the fractal parameter H (mean) is correlated with 3D microCT parameters and mechanical properties of femoral head bone samples, which suggests that radiographic texture analysis is a suitable approach for trabecular bone microarchitecture assessment in osteoporotic femurs.

An overview of vertebroplasty: current status, controversies, and future directions

Vertebroplasty is a cost-effective procedure for the relief of pain in appropriately selected patients when performed by a skilled practitioner. The currently accepted indications and contraindications for vertebroplasty are reviewed. The techniques routinely used by the authors are presented, including a discussion of recognized complications. Recent controversy has highlighted weaknesses in the practice of technology evaluation, and more robust studies will be required to address these issues across the board in the future more scientifically than has been done in the past.

Percutaneous vertebral augmentation: the status of vertebroplasty and current controversies

Vertebroplasty is a cost-effective procedure for the relief of pain and suffering in the appropriate patient when done by a skilled practitioner under good image guidance. No study has ever shown any cost benefit of any balloon-based osteoporotic spine intervention over simple vertebroplasty. No study has ever shown any benefit of any intravertebral implant over vertebroplasty for osteoporotic compression fracture. Recent controversy has highlighted weaknesses in our practice of technology evaluation, and we need to address these issues across the board in the future more scientifically then we have done in the past.

Osteoid osteoma of the midfoot: percutaneous radiofrequency treatment in 2 cases

Osteoid osteoma should be considered as a potential diagnosis in cases of chronic midfoot pain in younger individuals. If proper precautions are taken, percutaneous radiofrequency ablation may be considered a safe and efficient alternative to surgical resection in the treatment of osteoid osteomas, even in the small bones of the midfoot. We report on 2 cases of osteoid osteoma, 1 in the lateral cuneiform, and the other at the base of the second metatarsal, that were successfully treated with percutaneous radiofrequency ablation. Preoperative imaging studies, procedure technique, and clinical outcome are presented.

Floating fat in the wrist joint and in the tendon sheaths

A traumatic fat effusion in a tendon sheath is an unreported entity. We report on the clinical and imaging features, including radiography and computed tomography (CT), of a fat-density effusion in the wrist joint and tendon sheaths of the extensor pollicis longus, extensor carpi radialis longus, and extensor carpi radialis brevis in a 28-year-old patient after a roller-skating accident. Radiographs showed a fracture of the distal radius and a wrist joint effusion. Preoperative CT examination exhibited two distinct layers resulting in a fat-fluid level pathognomonic of lipohemarthrosis in the radiocarpal joint. In addition, a fat-density effusion was noted in the sheaths of the second and third compartment extensor tendons. The lipohemarthrosis depicted on imaging classically results from the extrusion of fat from bone marrow into the joint space after an intraarticular fracture. Similarly, a traumatic fat effusion in a tendon sheath presents characteristic imaging features that may help to diagnose a potentially overlooked fracture.

Transient medial patellar dislocation: injury patterns at US and MR imaging

Medial dislocation of the patella is an unusual entity. It is usually an iatrogenic complication of surgical lateral retinacular release. We describe the clinical, ultrasound (US), and magnetic resonance (MR) imaging features of a transient medial patellar dislocation in a 19-year-old patient with trochlear groove dysplasia presenting no surgical history. US showed acute injury to the lateral patellar retinaculum with complete avulsion at its patellar insertion. MR imaging confirmed the complete tear of the lateral patellar retinaculum and disclosed contusion of the anteromedial portion of the medial femoral condyle and lateral patella. This case is noteworthy because the injury patterns of patellar soft tissue restraints differ markedly from the classical features of lateral patellar dislocation.

Sonographic diagnosis of a cervical vagal schwannoma

This case report illustrates the role of high-resolution sonography in the preoperative assessment of a schwannoma of the vagus nerve in the neck. Sonography identified the tumor in the right carotid space and determined its origin from the right vagus nerve, facilitating the surgeon's approach to preserve nerve function.

Mineralized fibroma of the tendon sheath presenting as a bursitis

We report on the clinical, imaging-including ultrasound, computed tomography, and magnetic resonance imaging-and histological features of a fibroma of the tendon sheath with mineralized chondroid and osseous metaplasia, presenting as a semimembranosus bursitis. The anatomical characteristics of the semimembranosus bursa are demonstrated by dissection in a cadaveric specimen and correlated with the imaging findings in our patient.

Sonography of the painful shoulder: role of the operator's experience

OBJECTIVE

The aim of our study was to determine the role of the operator's experience in the sonographic evaluation of the painful shoulder and to validate assumptions about its technical performance in routine practice.

MATERIALS AND METHODS

Two radiologists, respectively standard and expert sonographic operators, independently and prospectively scanned 65 patients with clinical suspicion of rotator cuff lesion. Magnetic resonance arthrography was the reference standard.

RESULTS

The sensitivity of the expert ultrasound operator was 95.3% for full-thickness rotator cuff tears (41/43), 70.6% for partial-thickness tears (12/17), 64.3% for intratendinous tears (9/14), 100% for abnormality of the long head of biceps tendon (seven of seven), 88.9% for supraspinatus tendinosis (16/18), 96.4% for subacromial bursa abnormalities (53/55), and 91.7% for acromioclavicular joint osteoarthritis (33/36). The two sonographic operators were in very good agreement about full-thickness rotator cuff tears (kappa = 0.90), supraspinatus tendinosis (kappa = 0.80), abnormalities of the long head of biceps tendon (kappa = 0.84), subacromial bursa abnormalities (kappa = 0.89), and acromioclavicular osteoarthritis (kappa = 0.81). The agreement was only moderate for partial-thickness tears (kappa = 0.63) and intratendinous tears (kappa = 0.57).

CONCLUSIONS

Our results show that in moderately experienced hands as in experts' hands, sonography has a low level of interobserver variability for full-thickness rotator cuff tears. Considering partial-thickness and intratendinous rotator cuff tears, our data suggest that interobserver variability is higher.

Diffuse mineralization of forearm extraskeletal chondroma

We report on the clinical, histologic, and radiologic features - including CT and MRI - of extraskeletal chondroma in a rare case of diffuse calcification of the chondroid matrix. T2-weighted MR imaging showed a well-demarcated mass of low signal intensity in the left flexor digitalis profundus, with a slight surrounding intramuscular edema. Histopathological examination revealed a heavily calcified soft-tissue chondroma generating macrophagic foreign body reaction. Knowledge of this unusual pattern of mineralization may help in the radiological diagnosis of extraskeletal chondroma.