COVID-19 vaccine safety in Scotland - background rates of adverse events of special interest.

OBJECTIVES: Mass COVID-19 vaccination commenced in December 2020 in Scotland. Monitoring vaccine safety relies on accurate background incidence rates (IRs) for health outcomes potentially associated with vaccination. This study aimed to quantify IRs in Scotland of adverse events of special interest (AESI) potentially associated with COVID-19 vaccination. STUDY DESIGN AND METHODS: IRs and 95% confidence intervals (CIs) for 36 AESI were calculated retrospectively for the pre-COVID-19 pandemic period (01 January 2015-31 December 2019) and the COVID-19 pandemic period (01 April 2020-30 November 2020), with age-sex stratification, and separately by calendar month and year. Incident cases were determined using International Classification of Diseases-10th Revision (ICD-10)-coded hospitalisations. RESULTS: Prepandemic population-wide IRs ranged from 0.4 (0.3-0.5 CIs) cases per 100,000 person-years (PYRS) for neuromyelitis optica to 478.4 (475.8-481.0 CIs) cases per 100,000 PYRS for acute renal failure. Pandemic population-wide IRs ranged from 0.3 (0.2-0.5 CIs) cases per 100,000 PYRS for Kawasaki disease to 483.4 (473.2-493.7 CIs) cases per 100,000 PYRS for acute coronary syndrome. All AESI IRs varied by age and sex. Ten AESI (acute coronary syndrome, acute myocardial infarction, angina pectoris, heart failure, multiple sclerosis, polyneuropathies and peripheral neuropathies, respiratory failure, rheumatoid arthritis and polyarthritis, seizures and vasculitis) had lower pandemic than prepandemic period IRs overall. Only deep vein thrombosis and pulmonary embolism had a higher pandemic IR. CONCLUSION: Lower pandemic IRs likely resulted from reduced health-seeking behaviours and healthcare provision. Higher IRs may be associated with SARS-CoV-2 infections. AESI IRs will facilitate future vaccine safety studies in Scotland.

Establishing a baseline for a national paediatric antimicrobial stewardship programme.

BACKGROUND: The majority of antimicrobial stewardship programmes focus on prescribing in adult populations; however, there is a recognized need for targeted paediatric antimicrobial stewardship to improve the quality and safety of prescribing amongst this patient group. OBJECTIVES: To describe the current epidemiology of antimicrobial prescribing in paediatric inpatient populations in Scotland to establish a baseline of evidence and identify priority areas for quality improvement to support a national paediatric antimicrobial stewardship programme. METHODS: A total of 559 paediatric inpatients were surveyed during the Scottish national point prevalence survey of healthcare-associated infections and antimicrobial prescribing, 2016. The prevalence of antimicrobial prescribing was calculated and characteristics of antimicrobial prescribing were described as proportions and compared between specialist hospitals and paediatric wards in acute hospitals. RESULTS: Prevalence of antimicrobial use in paediatric inpatients was 35.4% (95% CI = 31.6%-39.4%). Treatment of community- and hospital-acquired infections accounted for 47.1% and 20.7% of antimicrobial use, respectively, with clinical sepsis being the most common diagnosis and gentamicin the most frequently prescribed antimicrobial for the treatment of infection. The reason for prescribing was documented in the notes for 86.5% of all prescriptions and, of those assessed for compliance against local policy, 92.9% were considered compliant. CONCLUSIONS: Data from national prevalence surveys are advantageous when developing antimicrobial stewardship programmes. Results have highlighted differences in the prescribing landscape between paediatric inpatient populations in specialist hospitals and acute hospitals, and have informed priorities for the national antimicrobial stewardship programme, which reinforces the need for a targeted paediatric antimicrobial stewardship programme.

Correlation of histological and microbiological findings in septic and aseptic knee implant failure.

INTRODUCTION: The Musculoskeletal Infection Society (MSIS) has defined specific clinical and laboratory criteria for the diagnosis of periprosthetic joint infection (PJI). In this study we assessed the diagnostic utility of MSIS microbiological and histological criteria for PJI in 138 cases of septic and aseptic knee implant failure. MATERIALS AND METHODS: Intra-operative samples from 60 cases of knee septic implant failure (SIF) and 78 cases of aseptic implant failure (AIF), defined on the basis of clinical, laboratory and operative findings/surgical management, were analysed microbiologically and histologically. Findings were correlated with the final clinical diagnosis and the specificity, sensitivity, accuracy, positive and negative predictive value of MSIS microbiological and histological criteria for knee PJI were assessed. RESULTS: 80% of SIF cases showed culture of the same organism from two or more samples (ie MSIS microbiological criteria for definite PJI); 8.3% grew an organism from one sample, and 11.7% showed no growth from any sample. 23.1% of AIF cases grew an organism from one sample and 76.9% showed no growth from any sample. MSIS histological criteria for PJI identified 96.7% of SIF cases. The sensitivity, specificity, accuracy and positive and negative predictive value of MSIS histological criteria for PJI were 96.7%, 100%, 98.6%, 100% and 97.5%, respectively. MSIS microbiological and histological criteria identified all AIF cases. CONCLUSIONS: Knee PJI is more often identified by current MSIS histological than microbiological criteria. A significant proportion of SIF cases show either no growth or growth of an organism from only one sample. AIF is identified by both MSIS microbiological and histological criteria. Correlation of clinical, radiological and laboratory findings is required for the diagnosis of knee PJI.

Primary synovial chondromatosis: a reassessment of malignant potential in 155 cases.

OBJECTIVE: Primary synovial chondromatosis (PSC) is a rare disorder characterised by cartilage formation in synovium-lined joints, tendon sheaths and bursae. It is thought that PSC cartilage arises from the proliferation of mesenchymal cells, which exhibit cartilaginous metaplasia in subintimal connective tissue. There are reports of transformation of PSC to chondrosarcoma, although the precise incidence and nature of this complication is uncertain. In this study we carried out a retrospective review PSC to determine the incidence of sarcomatous change in this condition, in addition to the clinical, radiological and pathological features that characterise this complication MATERIALS AND METHODS: We reviewed 155 cases of PSC and identified 4 cases (3 in the hip joint; 1 in the elbow joint) of aggressive behaviour and chondrosarcoma-like histology. RESULTS: Radiologically, these cases were all reported as showing features consistent with PSC and aggressive extra-articular soft tissue/bone involvement. Histologically, in addition to typical features of PSC, there was morphological evidence of peri-articular soft tissue and, in 2 cases, bone involvement by an infiltrating cartilaginous tumour. These tumours all behaved as locally aggressive neoplasms and did not give rise to metastasis. CONCLUSION: Our findings show that chondrosarcoma arises infrequently in PSC (approximately 2.5 %), and that this complication occurs most commonly in the hip joint (approximately 11 % of cases of hip PSC). These tumours behaved mainly as low-grade, locally aggressive tumours analogous to atypical cartilaginous tumour of bone/grade 1 chondrosarcoma of bone.

Efficient national surveillance for health-care-associated infections.

BACKGROUND: Detecting novel healthcare-associated infections (HCAI) as early as possible is an important public health priority. However, there is currently no evidence base to guide the design of efficient and reliable surveillance systems. Here we address this issue in the context of a novel pathogen spreading primarily between hospitals through the movement of patients. METHODS: Using a mathematical modelling approach we compare the current surveillance system for a HCAI that spreads primarily between hospitals due to patient movements as it is implemented in Scotland with a gold standard to determine if the current system is maximally efficient or whether it would be beneficial to alter the number and choice of hospitals in which to concentrate surveillance effort. RESULTS: We validated our model by demonstrating that it accurately predicts the risk of meticillin-resistant Staphylococcus aureus bacteraemia cases in Scotland. Using the 29 (out of 182) sentinel hospitals that currently contribute most of the national surveillance effort results in an average detection time of 117 days. A reduction in detection time to 87 days is possible by optimal selection of 29 hospitals. Alternatively, the same detection time (117 days) can be achieved using just 22 optimally selected hospitals. Increasing the number of sentinel hospitals to 38 (teaching and general hospitals) reduces detection time by 43 days; however decreasing the number to seven sentinel hospitals (teaching hospitals) increases detection time substantially to 268 days. CONCLUSIONS: Our results show that the current surveillance system as it is used in Scotland is not optimal in detecting novel pathogens when compared to a gold standard. However, efficiency gains are possible by better choice of sentinel hospitals, or by increasing the number of hospitals involved in surveillance. Similar studies could be used elsewhere to inform the design and implementation of efficient national, hospital-based surveillance systems that achieve rapid detection of novel HCAIs for minimal effort.

Time-Scaled Evolutionary Analysis of the Transmission and Antibiotic Resistance Dynamics of Staphylococcus aureus Clonal Complex 398.

Staphylococcus aureus clonal complex 398 (CC398) is associated with disease in humans and livestock, and its origins and transmission have generated considerable interest. We performed a time-scaled phylogenetic analysis of CC398, including sequenced isolates from the United Kingdom (Scotland), along with publicly available genomes. Using state-of-the-art methods for mapping traits onto phylogenies, we quantified transitions between host species to identify sink and source populations for CC398 and employed a novel approach to investigate the gain and loss of antibiotic resistance in CC398 over time. We identified distinct human- and livestock-associated CC398 clades and observed multiple transmissions of CC398 from livestock to humans and between countries, lending quantitative support to previous reports. Of note, we identified a subclade within the livestock-associated clade comprised of isolates from hospital environments and newborn babies, suggesting that livestock-associated CC398 is capable of onward transmission in hospitals. In addition, our analysis revealed significant differences in the dynamics of resistance to methicillin and tetracycline related to contrasting historical patterns of antibiotic usage between the livestock industry and human medicine. We also identified significant differences in patterns of gain and loss of different tetracycline resistance determinants, which we ascribe to epistatic interactions between the resistance genes and/or differences in the modes of inheritance of the resistance determinants.

The disease burden of hepatitis B, influenza, measles and salmonellosis in Germany: first results of the burden of communicable diseases in Europe study.

Setting priorities in the field of infectious diseases requires evidence-based and robust baseline estimates of disease burden. Therefore, the European Centre for Disease Prevention and Control initiated the Burden of Communicable Diseases in Europe (BCoDE) project. The project uses an incidence- and pathogen-based approach to measure the impact of both acute illness and sequelae of infectious diseases expressed in disability-adjusted life years (DALYs). This study presents first estimates of disease burden for four pathogens in Germany. The number of reported incident cases adjusted for underestimation served as model input. For the study period 2005-2007, the average disease burden was estimated at 33 116 DALYs/year for influenza virus, 19 115 DALYs/year for Salmonella spp., 8708 DALYs/year for hepatitis B virus and 740 DALYs/year for measles virus. This methodology highlights the importance of sequelae, particularly for hepatitis B and salmonellosis, because if omitted, the burden would have been underestimated by 98% and 56%, respectively.

The outcomes of acute periprosthetic joint infection following unicompartmental knee replacement managed with early debridement, Antibiotics, and implant retention.

BACKGROUND: Periprosthetic joint infection (PJI) following unicompartmental knee replacement (UKR) is an uncommon, yet serious, complication. There is a paucity of evidence regarding the effectiveness of Debridement-Antibiotics-and-Implant-Retention (DAIR) in this setting. The aim of this study is to investigate the effectiveness of DAIR for acute UKR PJI. METHOD: Between 2006 and 2019, 5195 UKR were performed at our institution. Over this period, sixteen patients underwent DAIR for early, acute PJI. All patients met MSIS PJI diagnostic criteria. The median age at DAIR was 67 years (range 40-73) and 12 patients were male (75.0%). The median time to DAIR was 24 days (range 6-60). Patients were followed up for a median of 6.5 years (range1.4-10.5) following DAIR. RESULTS: 0.3% (16/5195) of UKR in our institution had a DAIR within 3 months. 15 of 16 patients (93.8%) were culture positive, with the most common organism MSSA (n = 8, 50.0%). Patients were treated with an organism-specific intravenous antibiotic regime for a median of 6 weeks, followed by oral antibiotics for a median duration of 6 months. The Kaplan-Meier survivor estimate for revision for PJI was 57% (95%CI: 28-78%) at five years, and survivor estimate for all cause revision 52% (95%CI: 25-74%).The median Oxford Knee Score for patients with a viable implant at final follow-up was 45 points (range 39-46). CONCLUSION: Early, acute PJI after UKR is rare. DAIR had a moderate success rate, with infection-free survivorship of 57% at 5 years. Those successfully treated with DAIR had excellent functional outcome and implant survival.

A multidisciplinary approach to giant cell tumors of tendon sheath and synovium--a critical appraisal of literature and treatment proposal.

Giant cell tumors deriving from synovium are classified into a localized (GCT of tendon sheath; GCT-TS) and diffuse form (diffuse-type GCT, Dt-GCT). We propose a multidisciplinary management based upon a systematic review and authors' opinion. Open excision for GCT-TS and open synovectomy (plus excision) for Dt-GCT is advised to reduce the relatively high recurrence risk. External beam radiotherapy should be considered in severe cases, as Dt-GCT commonly extends extra-articular.

Giant cell tumor with pathologic fracture: should we curette or resect?

BACKGROUND: Approximately one in five patients with giant cell tumor of bone presents with a pathologic fracture. However, recurrence rates after resection or curettage differ substantially in the literature and it is unclear when curettage is reasonable after fracture. QUESTIONS/PURPOSES: We therefore determined: (1) local recurrence rates after curettage with adjuvants or en bloc resection; (2) complication rates after both surgical techniques and whether fracture healing occurred after curettage with adjuvants; and (3) function after both treatment modalities for giant cell tumor of bone with a pathologic fracture. METHODS: We retrospectively reviewed 48 patients with fracture from among 422 patients treated between 1981 and 2009. The primary treatment was resection in 25 and curettage with adjuvants in 23 patients. Minimum followup was 27 months (mean, 101 months; range, 27-293 months). RESULTS: Recurrence rate was higher after curettage with adjuvants when compared with resection (30% versus 0%). Recurrence risk appears higher with soft tissue extension. The complication rate was lower after curettage with adjuvants when compared with resection (4% versus 16%) and included aseptic loosening of prosthesis, allograft failure, and pseudoarthrosis. Tumor and fracture characteristics did not increase complication risk. Fracture healing occurred in 24 of 25 patients. Mean Musculoskeletal Tumor Society score was higher after curettage with adjuvants (mean, 28; range, 23-30; n = 18) when compared with resection (mean, 25; range, 13-30; n = 25). CONCLUSIONS: Our observations suggest curettage with adjuvants is a reasonable option for giant cell tumor of bone with pathologic fractures. Resection should be considered with soft tissue extension, fracture through a local recurrence, or when structural integrity cannot be regained after reconstruction. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Intraosseous schwannoma in schwannomatosis.

This study investigates the clinical, radiological, and pathological features of two cases of intraosseous schwannoma that arose in patients with multiple soft tissue schwannomas. In both cases, the patients were adult females and the tibial bone was affected. Vestibular schwannomas were not identified, indicating that these were not cases of neurofibromatosis 2 (NF2). Radiographs showed a well-defined lytic lesion in the proximal tibia; in one case, this was associated with a pathological fracture. Histologically, both cases showed typical features of benign schwannoma. Molecular analysis of one of the excised tumors showed different alterations in the NF2 gene in keeping with a diagnosis of schwannomatosis. Our findings show for the first time that intraosseous schwannomas can occur in schwannomatosis.

Giant-cell-rich pseudotumour in Paget's disease.

Paget's disease (PD) of the bone is a disorder of bone remodelling that may be polyostotic or monostotic. Although development of a sarcoma in PD is well-recognised, it is less well recognised that pseudosarcomas in bone and soft tissue can also arise in this condition. In this report we document the case of a large giant-cell-rich pseudotumour that developed in the tibia and overlying soft tissues in a case of polyostotic PD. Bone and soft tissues were highly vascular and contained abundant haemorrhage with focal areas of new bone formation and a diffuse infiltrate of osteoclastic giant cells. The lesion has not recurred or produced metastases 3 years after removal. Clinicians should be aware that a benign giant-cell-rich pseudotumour can develop in PD and that it needs to be distinguished from other giant-cell-rich tumours.

Osteoclast formation and function in pigmented villonodular synovitis.

Pigmented villonodular synovitis (PVNS) is a synovial tumour-like lesion that frequently causes osteolysis. PVNS contains numerous macrophages and osteoclast-like giant cells. In this study, we have analysed the cytochemical and functional characteristics of mononuclear and multinucleated cells in PVNS and determined the cellular and humoral mechanisms underlying giant cell formation and resorption in PVNS. Giant cells and CD14(+) and CD14(-) mononuclear cell populations were isolated from PVNS synovial tissue and cultured alone or in the presence and absence of the osteoclastogenic factors, RANKL and M-CSF. Osteoclast formation and activity was assessed by expression of TRAP and evidence of lacunar resorption. Giant cells in PVNS expressed an osteoclast-phenotype (CD51(+) , TRAP(+) , CD14(-) , HLA-DR(-) ) and were formed only in cultures of mononuclear cells that expressed the macrophage marker CD14. Osteoclast formation required RANKL and occurred in both the presence and absence of exogenous M-CSF. CD14(-) cells in PVNS expressed RANKL. Lacunar resorption by PVNS-derived giant cells was abolished by the addition of the bisphosphonate, zoledronate. Our findings indicate that osteoclasts form by a RANKL-dependent mechanism from CD14(+) mononuclear phagocytes in PVNS. Osteoclast formation occurred even in the absence of exogenous M-CSF, a finding which is in keeping with over-expression of M-CSF playing a pathogenic role in this condition. Anti-osteoclast resorptive treatment may be useful to control osteolysis in PVNS.

The management and outcome of large volume liposarcomas encasing the sciatic nerve.

This paper outlines the oncological outcomes of patients with large volume liposarcomas of the posterior thigh who underwent nerve-preserving surgery utilising epineural dissection. Thirty-seven consecutive patients (group I) with a mean age of 66.2 (31-96) were surgically treated with a planned marginal resection and epineurectomy for liposarcoma with known sciatic nerve involvement between March 1997 and January 2015. The mean follow-up was 79 months (15-192). All patients underwent multidisciplinary team (MDT) pre-operative assessment and staging, with follow-up in Sarcoma Clinic. Pre-operative function was assessed by applying the Toronto extremity salvage score (TESS). Oncological and functional outcomes were recorded. In grades 1, 2, and 3, 24, 6, and 7 liposarcomas, respectively, were included with mean volume 1859 cm3. Sciatic nerve involvement extended for 13-30 cm; in one case, the nerve was abutting the tumour throughout its length. Soft tissue reconstructive surgery was required in three cases. The remainder underwent direct primary closure. Seventeen patients underwent post-operative adjuvant radiotherapy 46-60 Gy and three received chemotherapy. There was local recurrence of disease in three patients. One patient had post-radiation wound breakdown treated non-operatively. Three patients died of an unrelated cause. When compared to a cohort of 37 patients without sciatic nerve involvement (group II), there were no significant differences in local and systemic recurrence rate or post-operative survival. In conclusion, sciatic nerve-preserving surgery is both possible and safe when using a planned epineural dissection in large volume tumours encasing the sciatic nerve.

Anterior knee pain from the evolutionary perspective.

BACKGROUND: This paper describes the evolutionary changes in morphology and orientation of the PFJ using species present through our ancestry over 340 million years. METHODS: 37 specimens from the Devonian period to modern day were scanned using a 64-slice CT scanner. 3D geometries were created following routine segmentation and anatomical measurements taken from standardised bony landmarks. RESULTS: Findings are described according to gait strategy and age. The adoption of an upright bi-pedal stance caused a dramatic change in the loading of the PFJ which has subsequently led to changes in the arrangement of the PFJ. From Devonian to Miocene periods, our sprawling and climbing ancestors possessed a broad knee with a shallow, centrally located trochlea. A more rounded knee was present from the Paleolithic period onwards in erect and bipedal gait types (aspect ratio 0.93 vs 1.2 in late Devonian), with the PFJ being placed lateral to the midline compared to the medial position in quadrapeds. The depth of the trochlea groove was maximal in the Miocene period of the African ground apes with associated acute sulcus angles in Gorilla (117°) becoming more flattened towards the modern human (138°). CONCLUSIONS: The evolving bipedal gait lead to anteriorisation of the patellofemoral joint, flattening of the trochlea sulcus, in a more lateral, dislocation prone arrangement. Ancestral developments might help explain the variety of presentations of anterior knee pain and patellofemoral instability.

Management of tenosynovial giant cell tumour of the foot and ankle.

AIMS: Tenosynovial giant cell tumour (TGCT) is one of the most common soft-tissue tumours of the foot and ankle and can behave in a locally aggressive manner. Tumour control can be difficult, despite the various methods of treatment available. Since treatment guidelines are lacking, the aim of this study was to review the multidisciplinary management by presenting the largest series of TGCT of the foot and ankle to date from two specialized sarcoma centres. METHODS: The Oxford Tumour Registry and the Leiden University Medical Centre Sarcoma Registry were retrospectively reviewed for patients with histologically proven foot and ankle TGCT diagnosed between January 2002 and August 2019. RESULTS: A total of 84 patients were included. There were 39 men and 45 women with a mean age at primary treatment of 38.3 years (9 to 72). The median follow-up was 46.5 months (interquartile range (IQR) 21.3 to 82.3). Localized-type TGCT (n = 15) predominantly affected forefoot, whereas diffuse-type TGCT (Dt-TGCT) (n = 9) tended to panarticular involvement. TGCT was not included in the radiological differential diagnosis in 20% (n = 15/75). Most patients had open rather than arthroscopic surgery (76 vs 17). The highest recurrence rates were seen with Dt-TGCT (61%; n = 23/38), panarticular involvement (83%; n = 5/8), and after arthroscopy (47%; n = 8/17). Three (4%) fusions were carried out for osteochondral destruction by Dt-TGCT. There were 14 (16%) patients with Dt-TGCT who underwent systemic treatment, mostly in refractory cases (79%; n = 11). TGCT initially decreased or stabilized in 12 patients (86%), but progressed in five (36%) during follow-up; all five underwent subsequent surgery. Side effects were reported in 12 patients (86%). CONCLUSION: We recommend open surgical excision as the primary treatment for TGCT of the foot and ankle, particularly in patients with Dt-TGCT with extra-articular involvement. Severe osteochondral destruction may justify salvage procedures, although these are not often undertaken. Systemic treatment is indicated for unresectable or refractory cases. However, side effects are commonly experienced, and relapses may occur once treatment has ceased. Cite this article: Bone Joint J 2021;103-B(4):788-794.

The effect of Imatinib Mesylate in diffuse-type Tenosynovial Giant Cell Tumours on MR imaging and PET-CT.

INTRODUCTION: Recurrence rates remain high after surgical treatment of diffuse-type Tenosynovial Giant Cell Tumour (TGCT). Imatinib Mesylate (IM) blocks Colony Stimulating Factor1 Receptor (CSF1R), the driver mechanism in TGCT. The aim of this study was to determine if IM reduces the tumour metabolic activity evaluated by PET-CT and to compare this response with the response seen on MR imaging. MATERIALS AND METHODS: 25 Consecutive patients treated with IM (off label use) for locally advanced (N = 12) or recurrent (N = 13) diffuse-type TGCT were included, 15 male and median age at diagnosis 39 (IQR 31-47) years. The knee was most frequently affected (n = 16; 64%). The effect of IM was assessed pre- and post-IM treatment by comparing MR scans and PET-CT. MR scans were assessed by Tumour Volume Score (TVS), an estimation of the tumour volume as a percentage of the total synovial cavity. PET-CT scans were evaluated based on maximum standardized uptake value (SUV-max). Partial response was defined as more than 50% tumour reduction with TVS and a decrease of at least 30% on SUV-max. RESULTS: Median duration of IM treatment was 7.0 (IQR 4.2-11.5) months. Twenty patients (80%) discontinued IM treatment for poor response or intended surgery. Twenty patients experienced an adverse event grade 1-2, three patients grade 3 (creatinine increment, neutropenic sepsis, liver dysfunction). MR assessment of all joints showed 32% (6/19) partial response and 63% (12/19) stable disease, with a mean difference of 12% (P = 0.467; CI -22.4-46.0) TVS between pre- and post-IM and a significant mean difference of 23% (P = 0.021; CI 4.2-21.6) in all knee lesions. PET-CT, all joints, showed a significantly decreased mean difference of 5.3 (P = 0.004; CI 1.9-8.7) SUV-max between pre- and post-IM treatment (58% (11/19) partial response, 37% (7/19) stable disease). No correlation between MR imaging and PET-CT could be appreciated in 15 patients with complete radiological data. CONCLUSION: This study confirms the moderate radiological response of IM in diffuse-type TGCT. PET-CT is a valuable additional diagnostic tool to quantify response to tyrosine kinase inhibitor treatment. Its value should be assessed further to validate its efficacy in the objective measurement of biological response in targeted systemic treatment of TGCT.

A cadaveric analysis of the blood supply to rectus Femoris.

BACKGROUND: Rectus femoris is a versatile muscle frequently used as a pedicled flap in reconstructive surgery. The anatomy and blood supply of rectus femoris needs to be clearly understood in order to safely preserve its reconstructive and functional capabilities. Classical anatomical description states that the proximal pedicle insertion into rectus femoris is 10- 15 cm from the anterior superior iliac spine (ASIS). The aim of this study was to dissect and identify the pedicular blood supply to rectus femoris and further map its morphology relative to the ASIS. METHODS: A dissection of 20 embalmed thighs from 10 cadavers was conducted. The distance of arterial insertions into rectus femoris from the ASIS were recorded. The cohort was 60% male of median age 79 with statistical significance defined as p < 0.05. RESULTS: 5%, 50%, and 45% of muscles demonstrated 1, 2, and 3 pedicles respectively. The mean distance from the ASIS to insertion of these pedicles was: proximal 13 cm (SD 2.6), middle 15 cm (SD 2.8), and distal 18 cm (SD 4.1). When grouped by number of pedicles, there was no difference in the mean height of proximal insertion. However, there was significant difference in mean intramuscular proximal-distal difference. These results were replicated when data were expressed as % of cadaver height. CONCLUSIONS: This study confirms the pedicular supply of rectus femoris but in contrast to classical literature demonstrates a greater range of pedicle insertions heights. We believe these observations should be considered when safely harvesting the pedicled rectus femoris flap.

Management and outcome of acral soft-tissue sarcomas.

AIMS: The aim of this study was to evaluate the surgical management and outcome of patients with an acral soft-tissue sarcoma of the hand or foot. PATIENTS AND METHODS: We identified 63 patients with an acral soft-tissue sarcoma who presented to our tertiary referral sarcoma service between 2000 and 2016. There were 35 men and 28 women with a mean age of 49 years (sd 21). Of the 63 sarcomas, 27 were in the hands and 36 in the feet. The commonest subtypes were epithelioid sarcoma in the hand (n = 8) and synovial sarcoma in the foot (n = 11). RESULTS: In 41 patients (65%), the tumour measured less than 5 cm in its largest dimension (median size 3 cm (2 to 6)); 27 patients (43%) were diagnosed after inadvertent excision prior to their referral to the specialist sarcoma unit. After biopsy and staging, primary surgical intervention at the sarcoma unit was excision and limb salvage in 43 (68%), partial (digit or ray) amputation in 14 (22%), and more proximal amputation in six (10%). At final follow up, local recurrence had been treated by one partial amputation and six amputations, resulting in a partial amputation rate of 24% and a proximal amputation rate of 19%. The five-year survival rate was 82%. Patients who underwent inadvertent excision showed no statistically significant difference in survival or local recurrence, but were more likely to undergo amputation (p = 0.008). Large tumour size (> 5 cm) was associated with lower survival (p = 0.04) and a higher risk of local recurrence (p = 0.009;). CONCLUSION: Most acral soft-tissue sarcomas measure less than 5 cm at presentation, indicating that while size can be a useful prognostic factor, it should not be used as a diagnostic threshold for referral. Increased tumour size is associated with a higher rate of local recurrence and reduced survival. Sarcoma excision with limb preservation does not result in an increased risk of local recurrence. Cite this article: Bone Joint J 2018;100-B:1518-23.

Pleomorphic liposarcoma of bone: a rare primary malignant bone tumour.

BACKGROUND: Liposarcoma is an extremely rare primary bone sarcoma. CASE PRESENTATION: We report a case of primary pleomorphic liposarcoma that arose in an 18 year old male in the metaphysis of the left tibia. Plain radiographs showed a partly sclerotic lesion and MR imaging a heterogeneous tumour predominantly isointense on T1- and high-signal on T2-weighted sequences with focal areas of increased T1 signal that suppressed with fat saturation. PET/CT showed marked FDG uptake (SUV = 17.1) in the primary tumour as well as a metastasis in the right distal femur and multiple small pulmonary metastases. Histologically, the tumour was a pleomorphic liposarcoma containing large tumour cells with vacuolated cytoplasm and hyperchromatic pleomorphic nuclei as well as numerous lipoblasts and scattered brown fat-like cells. Tumour cells strongly expressed FABP4/aP2, a marker of adipocyte differentiation, and UCP1, a marker of brown fat, but not S100. The case was treated with neoadjuvant MAP chemotherapy, resulting in extensive (> 95%) necrosis in the primary tumour and almost complete resolution of the femoral and pulmonary metastases. CONCLUSIONS: Pleomorphic liposarcoma can present as a sclerotic primary malignant bone tumour; markers of adipose differentiation are useful in histological diagnosis and neoadjuvant MAP chemotherapy results in significant tumor necrosis.