The Haleem-Botchu classification: a novel CT-based classification for lumbar foraminal stenosis

PURPOSE

No clinical CT-based classification system is currently in use for lumbar foraminal stenosis. MRI scanners are not easily available, are expensive and may be contraindicated in an increasing number of patients. This study aimed to propose and evaluate the reproducibility of a novel CT-based classification for lumbar foraminal stenosis.

MATERIALS AND METHODS

The grading was developed as four grades: normal foramen-Grade 0, anteroposterior (AP)/superoinferior (SI) (single plane) fat compression-Grade 1, both AP/SI compression (two planes) without distortion of nerve root-Grade 2 and Grade 2 with distortion of nerve root-Grade 3. A total of 800 lumbar foramen of a cohort of 100 random patients over the age of 60 who had undergone both CT and MRI scans were reviewed by two radiologists independently to assess agreement of the novel CT classification against the MRI-based grading system of Lee et al. Interobserver(n = 400) and intraobserver agreement(n = 160) was also evaluated. Agreement analysis was performed using the weighted kappa statistic.

RESULTS

A total of 100 patients (M:F = 45:55) with a mean age of 68.5 years (range 60-83 years were included in the study. The duration between CT and MRI scans was 98 days (range 0-540, SD-108). There was good correlation between CT and MRI with kappa scores (k = 0.81) and intraobserver kappa of 0.89 and 0.98 for the two readers.

CONCLUSION

The novel CT-based classification correlates well with the MRI grading system and can safely and accurately replace it where required.

Psoas muscle atrophy following unilateral hip arthroplasty

BACKGROUND

Studies have demonstrated the presence of muscle atrophy around the hip in patients with hip osteoarthritis. Few studies have examined the psoas muscle or assessed it at a paraspinal level in patients post-total hip arthroplasty. The aim of this study was to determine if there is significant psoas muscle atrophy as indicated by muscle cross-sectional area and high degree of fat infiltration post-unilateral hip arthroplasty.

METHODS

Retrospective analysis of 341 patients with unilateral hip implant and subsequent lumbar spine MRI over a 8-year period was performed. Fat infiltration and cross-sectional area of the psoas muscle at L3/4 level were measured by two musculoskeletal fellows (1 year experience in musculoskeletal radiology), and comparison made between the implant and non-operative sides was made. Fat infiltration was measured using the modified Goutallier grading. The degree of hip osteoarthritis in the non-operative side was measured using the Kellgren-Lawrence grading. The data was analysed using paired t test, ANOVA, unpaired t test, Pearson correlation and Jonckheere-Terpstra test.

RESULTS

The cross-sectional area of the psoas muscle on the implant side was significantly less than the non-operative side. There was significance between the cross-sectional area difference and the fat grade of the implant side.

CONCLUSION

Our results demonstrate psoas atrophy on the implant side compared to the non-operative side in post-unilateral implant patients. Post-operative hip implant rehabilitation may benefit from more focused psoas strengthening exercises to improve functional outcome.

Hamstring origin-anatomy, angle of origin and its possible clinical implications

INTRODUCTION

The posterior compartment of the thigh is composed of three major muscles collectively known as the hamstring muscles. These consist of the biceps femoris short and long head, semimembranosus and semitendinosus. Excluding the short head of biceps femoris, the hamstrings contribute to the movement of the hip and the knee joints as they span across both joints. Our hypothesis is that the nature of the conjoint tendon -ischial angle predisposes to an increased risk of tearing in this hamstring component. We therefore aim to look at the anatomy of the hamstring origin at the ischial tuberosity and spatial relationship between the long head of biceps, semitendinosus and semimembranosus in the form of vector angles.

MATERIAL AND METHODS

100 consecutive pelvic MRIs in patients under the age of 40 years were reviewed by musculoskeletal radiology fellow and a consultant musculoskeletal radiologist with more than 10 years' experience in musculoskeletal radiology and measured the angle of origin of conjoined tendon and semimembranosus at its ischial origin. P value using a paired t-test was less than 0.0001 confirming that the difference in the vector angle of the different hamstring components was statistically significant.

RESULTS

The median angle of origin of conjoined tendon was 12° and for semimembranosus was 6°. Applying the concept of Newton's second law to the angles calculated we demonstrated that an increase of 9% force applied to the conjoint tendon origin when compared to the semimembranosus tendon.

CONCLUSION

We hypothesis that the difference in the angle of origin of the components of hamstrings might be one of the reasons for the difference in the incidence and patterns of the injuries of the various muscles of the hamstrings.

MRI assessment of anatomy and pathology of the iliofemoral ligament

The iliofemoral ligament is strongest ligament of the body. We review the magnetic resonance imaging (MRI) appearances of the iliofemoral ligament, and discuss the disease entities that may affect this region.

Standard operating procedure of image-guided intervention during the COVID-19 pandemic: a combined tertiary musculoskeletal oncology centre experience

AIM

To evaluate the response measures in continuing an image-guided intervention service in two tertiary-level musculoskeletal oncology centres during the COVID-19 pandemic.

MATERIALS AND METHODS

This study was a retrospective review of all patients undergoing image-guided intervention in the computed tomography (CT) and normal ultrasound (US) rooms from 24 March 2020 to 24 May 2020 (during the COVID-19 pandemic peak) at Royal National Orthopaedic Hospital, London, and Royal Orthopaedic Hospital, Birmingham, UK. Measures were put in place to address air pressures, airflow direction, aerosol generation, and the safe utilisation of existing scanning rooms and work lists for interventional procedures.

RESULTS

Three hundred and thirty-one patients (164 at Royal National Orthopaedic Hospital and 167 at Royal Orthopaedic Hospital) underwent image-guided procedures at both sites in the CT and US rooms. At the Royal National Orthopaedic Hospital, 40% of all procedures were performed under general anaesthesia. These consisted of 47 CT biopsies, 7 CT radiofrequency ablations (RFAs), and 12 US biopsies. At the Royal Orthopaedic Hospital, 86% of all procedures were performed under local anaesthetic, with no general anaesthetic procedures. These consisted of 61 CT biopsies and 83 US biopsies. All 256 patients having procedures in the CT room had no post-procedural complications or COVID-19-related symptoms and morbidity on follow-up.

CONCLUSION

By adopting a pragmatic approach with meticulous planning, a limited, but fully functional image-guided interventional list can be run without any adverse patient outcomes.

•

COVID-19 has had a significant impact on CT interventional procedures.

•

Air pressures and appropriate ventilation systems need to be considered.

•

A pragmatic and meticulous approach is crucial in operating a functional service.

Power Doppler in musculoskeletal ultrasound: uses, pitfalls and principles to overcome its shortcomings

Power Doppler (PD) is used widely in musculoskeletal ultrasound, especially in the assessment of structures for evidence of inflammation and in evaluating soft tissue neoplasms. We reinforce and delineate the three cardinal principles of optimising PD assessment in order to avoid false positive or false negative results; namely (1) Optimal gain settings (2) Adequate transducer pressure, and (3) Proper patient/anatomical structure-of-interest positioning with complete tissue relaxation.

An imaging protocol for the management of central cartilage tumours of the proximal fibula

AIM

To retrospectively review a series of solitary central cartilage tumours (CCTs) of the proximal fibula and propose an imaging protocol for their management.

MATERIALS AND METHODS

Over 11 years, 48 patients were identified with a CCT of the proximal fibula. The initial magnetic resonance imaging (MRI) and follow-up imaging were assessed for tumour length, endosteal scalloping, or aggressive/malignant features. Each case was categorised according to the Birmingham Atypical Cartilage Tumour Imaging Protocol (BACTIP). The final diagnosis and outcome were reviewed to establish an appropriate imaging protocol for the management of similar cases in the future.

RESULTS

The final diagnosis based on imaging alone or imaging and histopathology was enchondroma in 46 cases (96%) and atypical cartilage tumour (ACT)/low-grade chondrosarcoma in two (4%). Using the BACTIP classification, the majority were type IC (48%) with type IA the second commonest (24%). Of 19 that underwent follow-up MRI, only two revealed any increase in length, neither of which was shown to be malignant. No cases re-presented later with evidence of malignant transformation.

CONCLUSION

There has been a significant increase in the number of CCTs of the proximal fibula referred to Royal Orthopaedic Hospital, Birmingham, over the past decade. This can largely be attributed to the increased use of MRI. The majority were benign with only 4% classified as an ACT. A modified BACTIP, the Fibular Atypical Cartilage Tumour Imaging Protocol (FACTIP) is presented, indicating which cases would benefit from follow-up imaging and which require referral to a specialist orthopaedic oncology service.

Computer assisted tumour surgery - An insight

Success in the management of bone sarcomas entails being able to achieve wide margins, which helps decrease the risk of local recurrence and provide an improvement in overall survival. The role of computer-assisted surgery has been investigated across various areas of orthopaedics, including joint replacement, cruciate ligament reconstruction, and pedicle screw placements which has led to increased interested in computer assisted tumour surgery (CATS). CATS can be used in a wide array of tumour surgeries, however its role in pelvic and sacral tumours is unparalled. Its importance lies in being able to provide radiological information to guide the surgeon at the time of surgery i.e. the distance from the tumour to the resection margin can be determined precisely based on preoperative planning and intra-operative image guidance. This minimises unnecessary bone resection, aiming to achieve good oncological and functional results which can be challenging in pelvic surgery. Most published articles on CATS have concentrated on the surgical aspects of navigation surgery. Although advanced imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) scans can provide anatomic detail about the primary tumour, the successful transfer of that information from a viewing screen to the intraoperative field can be difficult. The role of the radiologist lies in being able to provide appropriate imaging (CT, MRI) to facilitate surgical planning. This article aims at providing the radiologist a surgical insight on CATS and to facilitate optimal imaging in a patient tentatively being planned for CATS.

Osteochondroma-induced pseudoaneurysms of the extremities mimicking sarcoma: a report of seven contemporary and one historical case

AIM

To provide a diagnostic approach to distinguish osteochondroma-induced pseudoaneurysm from sarcoma on imaging and prevent biopsy which may be fatal.

MATERIALS AND METHODS

A retrospective study of the orthopaedic oncology database was performed to identify all patients referred to specialist orthopaedic oncology service with a final diagnosis of osteochondroma-induced pseudoaneurysm. The demographics of the cohort, the anatomical location of the osteochondromas and pseudoaneurysms, and the imaging appearances were assessed.

RESULTS

Seven contemporary and one historical case of osteochondroma-induced-pseudoaneurysm were identified. There were five patients with solitary osteochondroma and three cases of hereditary multiple exostosis. Five cases underwent magnetic resonance imaging (MRI) of which pulsation artefact was present in 40%. On MRI, all the present cases demonstrated a small central pseudoaneurysm surrounded by multiple eccentric layers of thrombus and haemorrhage, which was termed the "eccentric-whorl sign".

CONCLUSION

Osteochondroma-induced pseudoaneurysms are often misdiagnosed as malignant transformation of an osteochondroma or a soft-tissue sarcoma and referred for urgent biopsy. This study presents the largest case series, which includes the first documented case diagnosed in 1934. Differentiating and characterising pseudoaneurysms from sarcomas is imperative in order to prevent a biopsy, which could be fatal.

Anatomy and pathology of facet joint

Facet joints are the only synovial joints in the spine and can be involved in a large number of pathological processes including arthropathy, infection, inflammation, trauma and tumour. In this review article, we present a spectrum of pathologies that arise from or involve facet joints that we have encountered in our tertiary orthopaedic and spinal centre. The objective of this review is to create an aide memoire for the general radiologist who may encounter facet joint pathology, which they may not be familiar with.

Are the tubular bones of the hand really the commonest site for an enchondroma?

AIM

To investigate whether the long-held view that the hand is the commonest site for an enchondroma is actually correct in light of more sensitive imaging techniques that are able to demonstrate small enchondromas at other skeletal sites.

MATERIALS AND METHODS

A two-part retrospective study was undertaken. Part 1 comprised a review of the hand radiographs obtained in two major teaching hospitals over a 10-year period to establish the incidence of enchondroma in the hand. Part 2 was a review of a series of enchondromas of the proximal humerus, distal femur, and proximal tibia <4 cm in length on magnetic resonance imaging (MRI) to see which cases were visible or not on corresponding radiographs.

RESULTS

Part 1: 84 enchondromas were identified on 116,354 trauma radiographs to give an incidence of 0.07%. Part 2: 157 patients with an enchondroma on MRI <4 cm were reviewed. Only 17% of lesions <2 cm in length were visible on the contemporaneous radiographs. In lesions that were 2-2.9 and 3-3.9 cm the percentage visible on the radiographs increased to 58 and 77%, respectively.

CONCLUSION

It is well recognised from existing studies that incidental enchondromas can be seen in approximately 2.5% of routine shoulder and knee MRI scans. This figure is 35 times higher than the incidence found in the series of hand trauma radiographs. This infers that the hand should no longer be considered as the commonest site for an enchondroma. This is because radiographs are relatively insensitive to the detection of small lesions in larger bones, such as the proximal humerus and around the knee, when compared with MRI.

Anterior translation of the tibia in relation to femur in mucoid degeneration of ACL - An observational study

Background

Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) are a well-known pathological entity.We have encountered several patients with MD of the ACL, found to have a anterior translation of tibia a exceeding 5 mm with an intact ACL. We studied this cohort and investigated the likely cause of this.

Methods

A retrospective search of our department's radiology system to identify all patients referred from the knee orthopaedic clinic for MR imaging over a span of 10 years. All patients had MD within the substance of the ACL and an intact ACL. We evaluated the degree of anterior translation of the tibia (ATT) in relation to the femur in mucoid degeneration of ACL.

Results

We identified 464 consecutive cases. The mean age was 52 years. There was a male predominance of 261 to 203 female. The average PTF measurement was 2.4 mm with a range of 0-20mm. Of the 464 cases, 3 397 patients had an insignificant ATT of < 5 mm. (0mm. 67. 67 67 patients had a ATT >5 mm. Of them, 32.8% had a ATT of 6 mm, 53.7% had a ATT range between 7 and 9 mm, with the remaining 13.4% above 9 mm in length.

Conclusion

It is essential to look for other secondary signs of ACL tears and not only focus on ATT as well as correlate this with clinical findings.

Is acetabular morphology related to trochlear dysplasia?

PURPOSE

To evaluate the correlation between trochlear dysplasia and acetabular coverage.

MATERIALS AND METHODS

109 retrospective CT studies referred from the young adult knee clinic were independently reviewed by two observers. Anterior acetabular (AASA) and posterior acetabular (PASA) sector angles were calculated bilaterally on axial CT. Trochlear dysplasia was graded using the Dejour classification (A-D). ANOVA test was used.

RESULTS

Dejour types A, B and D trochlear dysplasia were associated with a significantly increased AASA (P value = 0.0011).

CONCLUSION

Our results demonstrate a significant relationship between trochlear dysplasia and anterior acetabular coverage, as measured by AASA.

Ultrasound of glenoid labrum with MR arthrographic correlation

Ultrasound (US) is a reliable non-invasive method to image the rotator cuff tendons. Even though glenoid labral pathology is common, it is not routinely looked at as part of the shoulder ultrasound protocol. Currently, the gold standard for labral imaging remains MR arthrography. However, given the rather long waiting list and cost implications, US may be used as a modality to quickly screen the shoulder for gross labral pathology. Whilst there is relative paucity of the literature outlining labral pathology on US, there is none correlating sonographic and corresponding MRI appearances. We present a pictorial review highlighting scanning positioning, US and corresponding MRI appearances of a normal labrum and various labral pathologies. We discuss useful scanning tips and characteristic US signs which can help the radiologist.

Osteochondromas of the cervical spine-case series and review

OBJECTIVE

Cervical spine osteochondromas are rare with approximately 3% of solitary and 7-9% of hereditary osteochondromas occurring in the spine. Almost 50% of spinal osteochondromas occur in the cervical region.

METHODS

A search of osteochondroma of cervical spine was performed of our radiology database.

RESULTS

In this study, we present 11 cases of adult cervical spine osteochondromas. These predominantly involved the posterior elements. The cartilage cap was more than 2 cm in 2 cases. There was cord compression in 1 case, foraminal narrowing in 2 patients and vertebral artery compression in 1 case. 6 patients underwent excision with majority being osteochondroma. There was only one case of chondrosarcoma.

CONCLUSION

Osteochondromas of cervical spine and extremely rare and symptomatology are due to mass effect. One should be aware of this entitly when analysing cervical spine for neck pain or lump.

Is T9-11 the true thoracolumbar transition zone?

OBJECTIVE

Degenerative thoracic stenosis has been shown to most frequently involve the lower thoracic segments (T9-T12) where there is greater mobility and vulnerability due to flexion, extension and rotation of the spine. The thoracolumbar junction is considered anatomically to be T12-L1; the anatomical transition between the relatively immobile thoracic spine and relatively mobile lumbar spine. From anecdotal experience at our institution, we hypothesise that the true thoracolumbar junction is higher, at T10-11; the point of transition from floating to false ribs resulting in increased mobility at T10-11.

METHODS AND MATERIALS

A retrospective review was performed of MRI lumbar and whole spine performed on patients aged 10-40 years in our institution over a 5-year period. Patients with previous surgery, chronic spinal disorders and congenital abnormalities were excluded from the study. Intervertebral discs from T8-9 to L1-2 were assessed for evidence of degeneration using the Pfirrmann grading system. Data obtained from a study using computer-based models to assess mean resultant loads in flexion, sitting and standing from T8-9 to L1-2 on patients aged 18-35 years was also analysed. The mean load gradients between two consecutive discs from T8 to L2 were analysed. Statistical analysis was performed with SPSS (p < 0.05 was considered statistically significant).

RESULTS

Three-hundred and twenty-two MRI studies were reviewed. Mean Pfirrmann grade was highest at T8-9 and T9-10 (1.35 ± 0.99 and 1.32 ± 0.93 respectively).Pfirrmann grade differed significantly at each level (χ² = 45.137 p = 0.001). Difference in mean load gradient from T9 to T11 was significantly higher than mean load gradient across T11 to L1 in both sitting and standing (0.095 ± 0.062 vs 0.050 ± 0.044 kN; p = 0.007, and 0.101 ± 0.061 kN vs 0.040 ± 0.054 kN; p = 0.007).

CONCLUSION

The changes in segmental loads and more severe disc degeneration at T9-11 compared to T11-L1 support our hypothesis that the true thoracolumbar transition is higher than expected, at T10-11; where the rib cage transitions from floating to false ribs.

The diagnostic significance of pulmonary nodules on CT thorax in chondrosarcoma of bone

AIM

To provide a diagnostic approach to pulmonary nodules in patients with chondrosarcoma.

MATERIALS AND METHODS

A search of the oncology database at a specialist orthopaedic oncology referral centre was performed to identify all patients who were treated surgically for chondrosarcoma between January 2007 and December 2018. Reports from the computed tomography (CT) examinations of the thorax of these patients were reviewed. In patients who had pulmonary nodules/metastases identified on CT, data on the primary chondrosarcoma and pulmonary nodule characteristics were collected.

RESULTS

Twenty point two percent of patients had a pulmonary nodule identified on either initial or follow-up staging CT of the thorax, of which 8.1% were pulmonary metastases. Patients with grade 3 and dedifferentiated chondrosarcoma were more likely to have pulmonary metastases than patients with grade 1/2 chondrosarcoma. The time interval to developing metastases was shorter in patients with grade 2/3 and dedifferentiated chondrosarcoma versus patients with grade 1 chondrosarcoma. A low proportion of patients with grade 1 chondrosarcoma developed metastases (12.5%), all of which were identified at the time of a local recurrence. Nodules ≥10mm, nodules with lobulate margins, nodules containing irregular or subtle calcification, and nodules seen bilaterally or both centrally and peripherally were more likely to represent pulmonary metastases than benign nodules.

CONCLUSION

The diagnostic significance of pulmonary nodules (i.e., whether they represent pulmonary metastases or not) can be predicted by taking into account a number of factors, in particular, the histological grade of the patient's chondrosarcoma, the size and margins of the nodules, and the presence of subtle/irregular calcification.

Master knot of Henry revisited: a radiologist's perspective on MRI

The master knot of Henry refers to a narrow space located between the anatomical crossover of the flexor hallucis longus and flexor digitorum longus tendons. This small space is prone to "intersection syndrome," as a result of tendinosis, tenosynovitis, and tears of the aforementioned tendons at the knot of Henry. The aim of this educational review is to detail the anatomy of the knot of Henry, including common variations in the tendon position and orientation. These complex interconnections can affect the outcome of surgical intervention if not appreciated at the time of treatment. We will also provide an overview of the common and rarer pathologies related to the knot of Henry. The aim of the present review is to make radiologists more aware of pathologies in this region, which are not routinely seen in daily practice.

Calcific tendinopathy of the direct head of rectus femoris: a rare cause of groin pain treated with ultrasound guided percutaneous irrigation

Groin pain can be caused by a myriad of pathologies. Abnormalities of the rectus femoris are a very rare cause of groin pain; calcific tendinopathy of the direct head is particularly so, with only two case reports in the literature. We report the first case of calcific tendinopathy of the direct head of the rectus femoris that was treated effectively with ultrasound-guided percutaneous irrigation of calcific tendinopathy (USPICT). The anatomy of the rectus femoris and the technique for US-PICT of the rectus femoris are also described.

Intra-neural ganglion cyst of the lateral dorsal cutaneous nerve: an uncommon cause of lateral ankle pain

INTRODUCTION

An intra-neural ganglion cyst of the lateral dorsal cutaneous branch of the sural nerve is rare, with only a few cases reported in the literature.

MATERIALS AND METHODS

We carried out a retrospective investigation of patients with an intraneural ganglion cyst of the lateral dorsal cutaneous nerve.

RESULTS

We present a case series of four patients with intra-neural ganglion cysts of the lateral dorsal cutaneous nerve, the distal continuation of the sural nerve at the lateral aspect of the foot.

CONCLUSION

Intra-neural ganglion cysts of the lateral dorsal cutaneous nerve are rare. They represent a relatively uncommon source of lateral ankle pain, which can easily be diagnosed with ultrasound (US) and magnetic resonance imaging and managed effectively with US-guided aspiration or surgical excision.

Brachialis tendinopathy: a rare cause of antecubital pain and ultrasound-guided injection technique

Antecubital pain can be caused by a myriad of pathologies. Abnormalities of the brachialis, in particular, tendinopathy at its insertion, are extremely rare, with no case report in the literature. We report the first case of tendinopathy of the brachialis tendon at its insertion in a 42-year-old male who presented with a year-long history of antecubital pain. The anatomy of the brachialis and the technique for ultrasound-guided steroid injection of the brachialis will also be described.

Isolated primary bone tumours of the lesser trochanter: Demographics, diagnosis and management

Primary bone tumours arising from the lesser trochanter (LT) are rare and the literature describing them is sparse. In this paper, we describe the largest series of LT tumours describing the demographics, diagnosis and management.

METHODS

A retrospective search of prospectively maintained radiology and oncology databases was performed to identify bone tumours of the LT diagnosed between 2007 and 2018. Metastatic lesions were excluded. All cases were re-reviewed by a senior Radiologist and all case of isolated tumours of the LT were included.

RESULTS

23 cases of isolated LT tumours were identified. There were 15 males and 8 females. Mean age of our cohort was 32 (14-63) years. Most (n = 19, 82.6%) cases had classic radiological (Radiographic, MR Imaging and CT) features and therefore did not undergo biopsy. 4 patients had equivocal radiological investigations that required biopsy to confirm the diagnosis. MR imaging was the most commonly used imaging modality for diagnosis (n = 17, 73.9%)There was a broad range of tumour subtypes, and osteochondroma (n = 17, 73.9%) the most frequently diagnosed. Surgical excision was performed in 4 patients (all osteochondromas) and 4 patients underwent therapeutic radiological guided hip injections for symptomatic relief. The remaining cases were managed conservatively and where they were identified incidentally, no intervention was required.

CONCLUSION

We report the largest case series of isolated primary bone tumours of the LT. All isolated primary bone tumours of LT are benign. Osteochondroma is the most common. The diagnosis can be made with on radiological investigations in most patients.

"Flow-void" sign in osseous metastatic renal cell carcinoma

AIM

To evaluate the frequency of the "flow-void" sign in a large series of pathologically proven renal cell carcinoma (RCC) bone metastases referred to a specialist unit and to evaluate its correlation with both lesion size and imaging sequence. A further aim was to describe a proposed grading system for the description of the "flow-void" sign.

MATERIALS AND METHODS

A retrospective review of patients with magnetic resonance imaging (MRI) of pathologically proven RCC bone metastases between September 2007 and December 2017 was performed. MRI images were reviewed for the presence of the "flow-void" sign and a proposed grading system for this sign was applied. Statistical analysis was performed to determine the association between the presence of the "flow-void" sign and lesion size and MRI sequence.

RESULTS

One hundred and forty bone lesions in 123 patients with histologically proven metastatic RCC were reviewed. One hundred and thirty-two (94.3%) lesions demonstrated the "flow-void" sign on at least one sequence in each study. A statistically significant difference was demonstrated between lesion size and the presence and type of "flow-void" sign. Lesions demonstrating type 3 "flow-void" sign had mean dimensions of 82.2 mm compared to 47.3 mm for lesions that did not demonstrate the "flow-void" sign (χ²(2) =11.4; p=0.01). T2-weighted, proton density and fat-saturated imaging also demonstrated the "flow-void" sign more frequently.

CONCLUSION

The "flow-void" sign is a common imaging feature within RCC bone metastases. When observed, the "flow-void" sign can be a useful imaging feature in the diagnosis of RCC bone metastases.

Correction to: Current concept in upright spinal MRI

Unfortunately, the legend of Fig. 5 was incorrectly published in original publication. The corrected legend is given below.

A diagnostic approach to popliteal fossa masses

There is a myriad of potential mass lesions that occur in the popliteal fossa, which present as palpable masses or are found incidentally on imaging. With a thorough knowledge and understanding of the appearances and locations of these different entities, one can narrow the differential diagnoses in the majority of cases. This will eliminate unnecessary additional investigations and enable a more rapid management. We present a review of frequently encountered and less common entities using an anatomical sieve, with the aim of providing a diagnostic approach to popliteal fossa masses.

Spinal imaging update

The widespread use of MRI has revolutionised the diagnostic process for spinal disorders. A typical protocol for spinal MRI includes T1 and T2 weighted sequences in both axial and sagittal planes. While such an imaging protocol is appropriate to detect pathological processes in the vast majority of patients, a number of additional sequences and advanced techniques are emerging. The purpose of the article is to discuss both established techniques that are gaining popularity in the field of spinal imaging and to introduce some of the more novel ‘advanced’ MRI sequences with examples to highlight their potential uses.

Cite this article: Bone Joint J 2015;97-B:1683–92.

Diagnostic triage for sarcoma: an effective model for reducing referrals to the sarcoma multidisciplinary team

OBJECTIVE

Soft-tissue lesions are common and often benign. Owing to the rarity of soft-tissue sarcomas (STSs), evidence has shown that patients are increasingly referred urgently onto the 2-week wait pathway, which may have a detrimental impact on the management of patients with a proven STS. Imaging plays a vital role in lesion characterization and can be used to triage referrals to reduce the caseload of a sarcoma multidisciplinary team (MDT). In our institution, we established a sarcoma diagnostic triage meeting (SDTM). This study aimed to determine the effectiveness of the SDTM in reducing non-sarcomatous referrals to the main sarcoma MDT.

METHODS

A retrospective review of the SDTM minutes from July 2011 to June 2012 was performed. Data collected for each case included details of referrer, referral modality and referral outcome.

RESULTS

165 cases were reviewed. 58% of referrals underwent a core biopsy or surgical excision with 85% benign pathology, the commonest being lipoma. 15% of referrals were sarcomatous lesions and were referred onwards to the main MDT.

CONCLUSION

A total of 82% of the patients referred urgently with a suspicious soft-tissue mass was managed by the SDTM and hence not referred onwards to the East Midlands Sarcoma Service MDT. A diagnostic triage is effective in reducing the caseload burden of the main MDT and allowing it to be more effective.

ADVANCES IN KNOWLEDGE

Referrals based on imaging can be prioritized by diagnostic triage. Diagnostic triage established in our institution reduced 82% of MDT referrals allowing a more focused MDT discussion on patients with a proven sarcoma.

Post-traumatic heterotopic ossification of distal tibiofibular syndesmosis mimicking a surface osteosarcoma

AIM

To present the imaging features of post-traumatic heterotopic ossification (HO) of the distal tibiofibular syndesmosis initially suspected to be a surface osteosarcoma.

MATERIALS AND METHODS

A retrospective review was conducted of the presenting complaint and imaging features of patients with a final diagnosis of HO referred over an 8 year period to a specialist orthopaedic oncology centre.

RESULTS

Five patients with HO were identified. All were adult males with an age range of 19-41 years. There was a history of prior ankle trauma in all cases but the significance was not recognized at the time of referral to the specialist centre. There was radiographic evidence of HO arising from the inner aspects of the distal tibia and fibula approximately 3 cm proximal to the ankle joint. The HO was "kissing" in two cases and partially fused (synostosis) in two. The HO in the fifth case was arising on the inner fibular cortex alone. Magnetic resonance imaging (MRI), available in four cases, showed predominantly low signal intensity due to the dense bone formation.

CONCLUSION

The history of prior ankle trauma with ossification arising from the inner aspects of both the distal tibia and fibula is typical of post-traumatic HO and distinguish this benign condition from the rare surface osteosarcoma at this site.

The MR arthrographic anatomy of the biceps labral insertion and its morphological significance with labral tears in patients with shoulder instability

INTRODUCTION

Most of the fibres of the long head of biceps tendon attach on the superior labrum just posterior to the supraglenoid tubercle.

AIM

Our hypothesis was that posteriorly attached biceps tendons predispose to posterior superior labral tears and SLAP lesions.

METHODS AND MATERIALS

A prospective analysis of all MR shoulder arthrograms for shoulder instability referred from the shoulder specialist clinics, performed during a one year period were reviewed by two independent observers who were blinded to clinical history. The biceps attachment was classified into four groups according to the method described in an earlier cadaveric study into four groups; posterior-type 1, predominantly posterior-type 2, equal contributions to both anterior and posterior labrum-type 3 and predominantly anterior labral attachment-type 4. Data was analysed using Kappa statistics and Fischer's exact test.

RESULTS

48 patients (33 males and 15 females) were included in this study with a mean age of 32 years. Majority, 22 patients (46%) had a type 1 attachment of the biceps on the superior labrum. There was moderate intra-observer and good interobserver agreement with a Kappa of 0.58 and 0.63 respectively. There was a significant association between a type 2 attachment and posterior tears (p≤0.04) and also between a type 2 attachment and SLAP tears (p≤0.04).

CONCLUSION

Our results suggest that variation in anatomy of biceps origin influences the type of labral tears that occur in patients with shoulder instability. The importance of these findings could influence selection of individuals in throwing sports like cricket and baseball.

Epidural emphysema following blunt trauma: a case report and review of literature

Pneumorachis or epidural emphysema is defined as free air in the spinal canal which is seen following trauma, head trauma, manipulations, epidural injections, and spinal surgery. We report on the case of a 62-year-old with cervical and thoracic pneumorachis following a traffic accident.

Compression of the deep branch of the ulnar nerve in Guyon's canal by a ganglion: two cases

INTRODUCTION

Ulnar nerve compression at the wrist can be caused by a variety of intrinsic and extrinsic factors. Isolated compression of only the deep branch of ulnar nerve by a ganglion is very uncommon. Ultrasound examination can clearly show the cystic lesion compressing the nerves.

MATERIALS AND METHODS

We present two cases of compression of deep branch of ulnar nerve by a ganglion in the Guyon's canal. Two male patients presented with history of progressive weakness and paraesthesia in the medial 1(1/2) digits of the non-dominant hand. Interestingly, both the patients noticed sudden onset and rapid progress of the symptoms and signs. Clinical examination revealed typical symptoms of ulnar nerve (deep branch) palsy. Nerve conduction studies showed severe denervation of the deep branch of the ulnar nerves in both the patients and ultrasound confirmed the diagnosis. Surgical decompression led to complete recovery.

RESULTS AND DISCUSSION

Whilst compression by a ganglion in the Guyon's canal is rare but well recognized, a feature of both of our cases was the rapid progression and severe nature of the compressive symptoms and signs. This is in contrast to the more typical features of compressive neuropathy and should alert the clinician to the possible underlying cause of compression. Early decompression has the potential to promote a complete recovery.

Septic hip after a fractured neck of femur in a rheumatoid patient: A case report

A 63-year-old rheumatoid patient presented with severe pain in her left hip without a preceding history of trauma. An initial clinical and radiological examination revealed no "obvious" abnormality and the patient was symptomatically treated. The patient presented again five weeks later as weightbearing became increasingly difficult due to worsening pain. Inflammatory markers were found to be elevated and a repeat radiological examination revealed a displaced ununited fracture of the neck of femur. Isotope imaging suggested increased activity around the hip. A formal arthrotomy revealed pus in the joint. She continued to deteriorate and subsequently died due to sepsis. Spontaneous fractures without any history of trauma have been described in patients with rheumatoid arthritis. The fracture haematoma serves as a good culture medium for micro-organisms in immuno-compromised rheumatoid patients. Any hip pain arising in a rheumatoid patient should be thoroughly investigated and a high index of suspicion is necessary for both sepsis and fracture. (Hip International 2005; 15: 59-61).