In two centres in Korea 350 patients with a diagnosis of tuberculosis of the thoracic and/or lumbar spine were allocated at random: in Masan to in-patient rest in bed (IP) for six months followed by out-patient treatment or to ambulatory out-patient treatment (OP) from the start; in Pusan to out-patient treatment with a plaster-of-Paris jacket (J) for nine months or to ambulatory treatment without any support (No J). All patients recieved chemotherapy with PAS with isoniazid for eighteen months, either supplemented with streptomycin for the first three months (SPH) or without this supplement (PH), by random allocation. The main analysis of this report concerns 299 patients (eighty-three IP, eighty-three OP, sixty-three J, seventy No J; 143 SPH, 156 PH). Pre-treatment factors were similar in both centres except that the patients in Pusan had, on average, less extensive lesions although in a greater proportion the disease was radiographically active. One patient (J/SPH) died with active spinal disease and three (all No J/SPH) with paraplegia. A fifth patient (IP/PH) who died from cardio respiratory failure also had pulmonary tuberculosis. Twenty-three patients required operation and/or additional chemotherapy for the spinal lesion. A sinus or clinically evident abscess was either present initially or developed during treatment in 41 per cent of patients. Residual lesions persisted in ten patients (four IP, two OP, one J, three No J; six SPH, four PH) at five years. Thirty-two patients had paraparesis on admission or developing later. Complete resolution occurred in twenty on the allocated regimen and in eight after operation or additional chemotherapy or both. Of the remaining four atients, all of whom had operation and additional chemotherapy, three died and one still had paraparesis at five years. Of 295 patients assessed at five years 89 per cent had a favourable status. The proportions of the patients responding favourably were similar in the IP (91 per cent) and OP (89 per cent) series, in the J (90 per cent) and No J (84 per cent) series and in the SPH (86 per cent) and PH (92 per cent) series

Streptomycin and the newer antibiotics have already belied the pessimistic agnosticism of 1947. In certain instances, notably in disease of the knee and hip and in some cases with draining sinuses, it appears that they are sufficient to produce a quiescence which may be a cure. For the rest it remains to map out in detail what has in part been explored. In particular it is essential to confirm how far antibiotics enable surgeons to treat tuberculosis upon the basic principles applicable to other infections of bone without fear of secondary infection: where there is diseased bone, to remove it: where there is pus, to relieve the tension and evacuate it. The surgeon fears not so much the infection itself as the inability of the tuberculous soil ordinarily to deal with secondary infection. With the control of the diseased soil the risk should be no greater than that of any other surgery of bone.

The early case and the advanced case; age and site of disease; these and other variables must subdivide basic method. What is the best application of the new "combined operation" to a child of three with thoracic Pott's disease and a globular abscess? What is the wisest plan for a man of forty with old disease in his lumbar vertebrae and discharging sinuses? We begin to see what we could do. At the present the question still remains: What should we do?

We studied 51 patients with osteo-articular tuberculosis who were divided into two groups. Group I comprised 31 newly-diagnosed patients who were given first-line antituberculous treatment consisting of isoniazid, rifampicin, ethambutol and pyrazinamide. Group II (non-responders) consisted of 20 patients with a history of clinical non-responsiveness to supervised uninterrupted antituberculous treatment for a minimum of three months or a recurrence of a previous lesion which on clinical observation had healed. No patient in either group was HIV-positive. Group II were treated with an immunomodulation regime of intradermal BCG, oral levamisole and intramuscular diphtheria and tetanus vaccines as an adjunct for eight weeks in addition to antituberculous treatment. We gave antituberculous treatment for a total of 12 to 18 months in both groups and they were followed up for a mean of 30.2 months (24 to 49). A series of 20 healthy blood donors served as a control group.

Twenty-nine (93.6%) of the 31 patients in group I and 14 of the 20 (70%) in group II had a clinicoradiological healing response to treatment by five months.

The CD4 cell count in both groups was depressed at the time of enrolment, with a greater degree of depression in the group-II patients (686 cells/mm³ (sd 261) and 545 cells/mm³ (sd 137), respectively; p < 0.05). After treatment for three months both groups showed significant elevation of the CD4 cell count, reaching a level comparable with the control group. However, the mean CD4 cell count of group II (945 cells/mm³ (sd 343)) still remained lower than that of group I (1071 cells/mm³ (sd 290)), but the difference was not significant. Our study has shown encouraging results after immunomodulation and antituberculous treatment in non-responsive patients. The pattern of change in the CD4 cell count in response to treatment may be a reliable clinical indicator.

Two hundred and eighty-three patients with tuberculosis of the thoracic and/or lumbar spine have been followed for 10 years from the start of treatment. All patients received PAS plus isoniazid daily for 18 months, either with streptomycin for the first three months (SPH) or no streptomycin (PH), by random allocation. There was also a second random allocation for all patients: in Masan to inpatient rest in bed (IP) for six months followed by outpatient treatment or to ambulatory outpatient treatment from the start (OP), and in Pusan to outpatient treatment with a plaster-of-Paris jacket (J) for nine months or to ambulatory treatment without any support (No J). A favourable status was achieved on their allocated regimen by 88% of patients at 10 years. Some of the remaining patients also attained a favourable status after additional chemotherapy and/or operation, and if these are included the proportion achieving such a status increases to 96%. There were five patients whose deaths were attributed to their spinal disease. A sinus or clinically evident abscess was present on at least one occasion in the 10-year period in 42% of the patients. Residual sinuses persisted at 10 years in two patients, at death at seven years in a third and at default in the seventh year in a fourth. Thirty-five patients had paraparesis at some time during the 10-year period, including two who died with paraplegia before five years. Complete resolution occurred in 26 patients (in six after additional chemotherapy and/or surgery). At 10 years two patients had severe paraplegia and one a moderate paraparesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Streptomycin and iso-nicotinic acid hydrazide are two powerful drugs lethal to tubercle bacilli, when access to the infected tissues is free. For early disease, before ischaemia and necrosis become established, they are curative: afterwards they are not. In this paper the use of surgery to augment their action has been discussed. The development of such methods may well revolutionise the treatment of skeletal tuberculosis. Therein lies a danger because attempts to cure the patient by exterminating the tubercle bacilli in his lesion may lead to a precarious recovery: treatment directed against the bacilli may greatly facilitate a real cure if constitutional treatment is also applied to make the patient immune. Revolutionary though the change may become, it will not be so great as the revolution which occurred thirty years ago when open-air hospitals were first provided for patients with skeletal tuberculosis. The first patient ever seen on a surgical ward by the author, when he was a student, suffices still as an example. A child with tuberculosis of the cervical spine was admitted from out-patients with multiple discharging sinuses from the neck which was supported in a sodden plaster jacket. "Whoever," said the house surgeon dramatically, "removes that plaster, will kill that child." Most unfortunately his words were true. Many other such patients could, in those days, be seen in the wards of city hospitals. It was largely due to the work of Sir Robert Jones, friend of children, that the value of constitutional treatment became recognised. With the combination of the old knowledge and the development of the new, a new chapter in the treatment of skeletal tuberculosis has opened and rapid restoration of function and permanent cure can now take the place of long and sometimes crippling illness.

One hundred and fifty patients in Hong Kong with a diagnosis of tuberculosis of the thoracic, thoracolumbar or lumbar spine were allocated a random to the "Hong Kong" radical resection of the lesion and the insertion of autologous bone grafts (Rad. series) or to debridement of the spinal focus without bone grafting (Deb. series). All patients received daily chemotherapy with para-aminosalicylic acid (PAS) plus isoniazid for 18 months, with streptomycin for the first three months. After exclusions, the main analyses of this report concern 119 patients (58 Rad., 61 Deb.) followed up for 10 years. During the first five years the allocated regimen was modified because of the spinal lesion in 14 patients, but there were no further modifications between five and 10 years. No patient developed a sinus or clinically evident abscess or a neurological abnormality between five and 10 years. Bony fusion occurred earlier and in a higher proportion of patients in the Rad, series but at five and 10 years there was vary little difference between the series. Over the period of 10 years there was a mean increase in vertebral loss of 0.05 of a vertebral body in the Rad. series and 0.23 in the Deb. series. In both series most of this loss occurred in the first 18 months, with very little subsequent change in the next eight and a half years. Over the 10 years there was a mean reduction in the angle of kyphosis in the Rad. series of 1.4 degrees for patients with thoracic and thoracolumbar lesions and 0.5 degrees for those with lumbar lesions. By contrast, in the Deb. series there were mean increases in the angle of 9.8 degrees and 7.6 degrees respectively. In both series most of the changes had occurred early, and persisted subsequently. At 10 years 57 of 58 Rad. and all 61 Deb. patients had a favourable status, 50 (86 per cent) and 54 (89 per cent) respectively on the allocated regimen without modification

Aims. The aim of this study was to determine the rate of indocyanine green (ICG) staining of bone and soft-tissue tumours, as well as the stability and accuracy of ICG fluorescence imaging in detecting tumour residuals during surgery for bone and soft-tissue tumours. Methods. ICG fluorescence imaging was performed during surgery in 34 patients with bone and soft-tissue tumours. ICG was administered intravenously at a dose of 2 mg/kg over a period of 60 minutes on the day prior to surgery. The tumour stain rate and signal-to-background ratio of each tumour were post hoc analyzed. After tumour resection, the tumour bed was scanned to locate sites with fluorescence residuals, which were subsequently inspected and biopsied. Results. The overall tumour stain rate was 88% (30/34 patients), and specific stain rates included 90% for osteosarcomas and 92% for giant cell tumours. For malignant tumours, the overall stain rate was 94%, while it was 82% for benign tumours. The ICG tumour stain was not influenced by different pathologies, such as malignant versus benign pathology, the reception (or lack thereof) of neoadjuvant chemotherapies, the length of time between drug administration and surgery, the number of doses of denosumab for patients with giant cell tumours, or the tumour response to neoadjuvant chemotherapy. The overall accuracy rate of successfully predicting tumour residuals using fluorescence was 49% (23/47 pieces of tissue). The accuracy rate after en bloc resection was significantly lower than that after piecemeal resection (16% vs 71%; p < 0.001). Conclusion. A high percentage of bone and soft-tissue tumours can be stained by ICG and the tumour staining with ICG was stable. This approach can be used in both benign and malignant tumours, regardless of whether neoadjuvant chemotherapy is adopted. The technique is also useful to detect tumour residuals in the wound, especially in patients undergoing piecemeal resection. Cite this article: Bone Joint J 2023;105-B(5):551–558

Aims. For paediatric and adolescent patients with growth potential, preservation of the physiological joint by transepiphyseal resection (TER) of the femur confers definite advantages over arthroplasty procedures. We hypothesized that the extent of the tumour and changes in its extent after neoadjuvant chemotherapy are essential factors in the selection of this procedure, and can be assessed with MRI. The oncological and functional outcomes of the procedure were reviewed to confirm its safety and efficacy. Methods. We retrospectively reviewed 16 patients (seven male and nine female, mean age 12.2 years (7 to 16)) with osteosarcoma of the knee who had been treated by TER. We evaluated the MRI scans before and after neoadjuvant chemotherapy for all patients to assess the extent of the disease and the response to treatment. Results. The mean follow-up period was 64.3 months (25 to 148) after surgery and no patients were lost to follow-up. On MRI evaluation, 13 tumours were near but not in contact with the physes and three tumours were partially in contact with the physes before neoadjuvant chemotherapy. Bone oedema in the epiphysis was observed in eight patients. After neoadjuvant chemotherapy, bone oedema in the epiphysis disappeared in all patients. In total, 11 tumours were not in contact and five tumours were in partial contact with the physes. The postoperative pathological margin was negative in all patients. At the last follow-up, 12 patients were continuously disease-free and three had no evidence of disease. One patient died due to the disease. Functionally, the patients with retained allograft or recycled autograft had a mean knee range of flexion of 126° (90° to 150°). The mean Musculoskeletal Tumor Society functional score was 27.6 (23 to 30). Conclusion. TER is an effective limb-salvage technique for treating malignant metaphyseal bone tumours in paediatric and young osteosarcoma patients with open physes when a good response to chemotherapy and no progression of the tumour to the epiphysis have been confirmed by MRI. Cite this article: Bone Joint J 2020;102-B(6):772–778

The April 2023 Oncology Roundup. 360. looks at: Complete tumour necrosis after neoadjuvant chemotherapy defines good responders in patients with Ewing’s sarcoma; Monitoring vascularized fibular autograft: are radiographs enough?; Examining patient perspectives on sarcoma surveillance; The management of sacral tumours; Venous thromboembolism and major bleeding in the clinical course of osteosarcoma and Ewing’s sarcoma; Secondary malignancies after Ewing’s sarcoma: what is the disease burden?; Outcomes of distal radial endoprostheses for tumour reconstruction: a single centre experience over 15 years; Is anaerobic coverage during soft-tissue sarcoma resection needed?; Is anaerobic coverage during soft-tissue sarcoma resection needed?

The February 2024 Oncology Roundup. 360. looks at: Does primary tumour resection improve survival for patients with sarcomas of the pelvis with metastasis at diagnosis?; Proximal femur replacements for an oncologic indication offer a durable endoprosthetic reconstruction option: a 40-year experience; The importance of awaiting biopsy results in solitary pathological proximal femoral fractures: do we need to biopsy solitary pathological fractures?; Effect of radiotherapy on local recurrence, distant metastasis, and overall survival in 1,200 extremity soft-tissue sarcoma patients; What to choose in bone tumour resections? Patient-specific instrumentation versus surgical navigation; Optimal timing of re-excision in synovial sarcoma patients: immediate intervention versus waiting for local recurrence; Survival differences of patients with resected extraskeletal osteosarcoma receiving two different (neo) adjuvant chemotherapy regimens; Solitary versus multiple bone metastases in the appendicular skeleton: should the surgical treatment be different?

The December 2022 Oncology Roundup. 360. looks at: Is high-dose radiation therapy associated with early revision with a cemented endoprosthesis?; Neoadjuvant chemotherapy and endoprosthetic reconstruction for lower extremity sarcomas: does timing impact complication rates?; Late amputation after treatment for lower extremity sarcoma; Osteosarcoma prediagnosed as another tumour: a report from the Cooperative Osteosarcoma Study Group; The influence of site on the incidence and diagnosis of solitary central cartilage tumours of the femur: a 21st century perspective

Aims. The aim of this study was to investigate the incidence and characteristics of instrumentation failure (IF) after total en bloc spondylectomy (TES), and to analyze risk factors for IF. Methods. The medical records from 136 patients (65 male, 71 female) with a mean age of 52.7 years (14 to 80) who underwent TES were retrospectively reviewed. The mean follow-up period was 101 months (36 to 232). Analyzed factors included incidence of IF, age, sex, BMI, history of chemotherapy or radiotherapy, tumour histology (primary or metastasis; benign or malignant), surgical approach (posterior or combined), tumour location (thoracic or lumbar; junctional or non-junctional), number of resected vertebrae (single or multilevel), anterior resection line (disc-to-disc or intravertebra), type of bone graft (autograft or frozen autograft), cage subsidence (CS), and local alignment (LA). A survival analysis of the instrumentation was performed, and relationships between IF and other factors were investigated using the Cox regression model. Results. A total of 44 patients (32.4%) developed IF at a median of 31 months (interquartile range 23 to 74) following TES. Most IFs were rod fractures preceded by a mean CS of 6.1 mm (2 to 18) and LA kyphotic enhancement of 10.8° (-1 to 36). IF-free survival rates were 75.8% at five years and 56.9% at ten years. The interval from TES to IF peaked at two to three years postoperatively and continued to occur over a period of time thereafter; the early IF-developing group had greater CS at one month postoperatively (CS1M) and more lumbar TES. CS1M ≥ 3 mm and sole use of frozen autografts were identified as independent risk factors for IF. Conclusion. IF is a common complication following TES. We have demonstrated that robust spinal reconstruction preventing CS, and high-quality bone grafting are necessary for successful reconstruction. Cite this article: Bone Joint J 2023;105-B(2):172–179

Aims. Socioeconomic and racial disparities have been recognized as impacting the care of patients with cancer, however there are a lack of data examining the impact of these disparities on patients with bone sarcoma. The purpose of this study was to examine socioeconomic and racial disparities that impact the oncological outcomes of patients with bone sarcoma. Methods. We reviewed 4,739 patients diagnosed with primary bone sarcomas from the Surveillance, Epidemiology and End Results (SEER) registry between 2007 and 2015. We examined the impact of race and insurance status associated with the presence of metastatic disease at diagnosis, treatment outcome, and overall survival (OS). Results. Patients with Medicaid (odds ratio (OR) 1.41; 95% confidence interval (CI) 1.15 to 1.72) and uninsured patients (OR 1.90; 95% CI 1.26 to 2.86) had higher risks of metastatic disease at diagnosis compared to patients with health insurance. Compared to White patients, Black (OR 0.63, 95% CI 0.47 to 0.85) and Asian/Pacific Islander (OR 0.65, 95% CI 0.46 to 0.91) were less likely to undergo surgery. In addition, Black patients were less likely to receive chemotherapy (OR 0.67, 95% CI 0.49 to 0.91) compared to White patients. In patients with chondrosarcoma, those with Medicaid had worse OS compared to patients with insurance (hazard ratio (HR) 1.65, 95% CI 1.06 to 2.56). Conclusion. In patients with a bone sarcoma, the cancer stage at diagnosis varied based on insurance status, and racial disparities were identified in treatment. Further studies are needed to identify modifiable factors which can mitigate socioeconomic and racial disparities found in patients with bone sarcomas. Cite this article: Bone Joint Res 2022;11(5):278–291

Aims. The purpose of this study was to clarify the clinical behaviour, prognosis, and optimum treatment of dedifferentiated low-grade osteosarcoma (DLOS) diagnosed based on molecular pathology. Patients and Methods. We retrospectively reviewed 13 DLOS patients (six men, seven women; median age 32 years (interquartile range (IQR) 27 to 38)) diagnosed using the following criteria: the histological coexistence of low-grade and high-grade osteosarcoma components in the lesion, and positive immunohistochemistry of mouse double minute 2 homolog (MDM2) and cyclin-dependent kinase 4 (CDK4) associated with MDM2 amplification. These patients were then compared with 51 age-matched consecutive conventional osteosarcoma (COS) patients (33 men, 18 women; median age 25 years (IQR 20 to 38)) regarding their clinicopathological features. Results. The five-year overall survival (OAS) rates in the DLOS and COS patients were 85.7% and 77.1% (p = 0.728), respectively, and the five-year progression-free survival (PFS) rates were 57.7% and 44.9% (p = 0.368), respectively. A total of 12 DLOS patients received chemotherapy largely according to regimens for COS. Among the nine cases with a histological evaluation after chemotherapy, eight showed a poor response, and seven of these had a necrosis rate of < 50%. One DLOS patient developed local recurrence and five developed distant metastases. Conclusion. Based on our study of 13 DLOS cases that were strictly defined by histological and molecular means, DLOS showed a poorer response to a standard chemotherapy regimen than COS, while the clinical outcomes were not markedly different. Cite this article: Bone Joint J 2019;101-B:745–752

Aims. The sacroiliac joint (SIJ) is the only mechanical connection between the axial skeleton and lower limbs. Following iliosacral resection, there is debate on whether reconstruction of the joint is necessary. There is a paucity of data comparing the outcomes of patients undergoing reconstruction and those who are not formally reconstructed. Methods. A total of 60 patients (25 females, 35 males; mean age 39 years (SD 18)) undergoing iliosacral resection were reviewed. Most resections were performed for primary malignant tumours (n = 54; 90%). The mean follow-up for surviving patients was nine years (2 to 19). Results. Overall, 27 patients (45%) were reconstructed, while 33 (55%) had no formal reconstruction. There was no difference in the use of chemotherapy (p = 1.000) or radiotherapy (p = 0.292) between the groups. Patients with no reconstruction had a mean larger tumour (11 cm (SD 5) vs 8 cm (SD 4); p = 0.014), mean shorter operating times (664 mins (SD 195) vs 1,324 mins (SD 381); p = 0.012), and required fewer blood units (8 (SD 7) vs 14 (SD 11); p = 0.012). Patients undergoing a reconstruction were more likely to have a deep infection (48% vs 12%; p = 0.003). Nine reconstructed patients had a hardware failure, with five requiring revision. Postoperatively 55 (92%) patients were ambulatory, with no difference in the proportion of ambulatory patients (89% vs 94%; p = 0.649) or mean Musculoskeletal Tumor Society Score (59% vs 65%; p = 0.349) score between patients who did or did not have a reconstruction. The ten-year disease-specific survival was 69%, with no difference between patients who were reconstructed and those who were not (78% vs 45%; p = 0.316). There was no difference in the rate of metastasis between the two groups (hazard ratio (HR) 2.78; p = 0.102). Conclusion. Our results demonstrate that SIJ reconstruction is associated with longer operating times, greater need for blood transfusion, and more postoperative infections, without any improvement in functional outcomes when compared to patients who did not have formal SIJ reconstruction. Cite this article: Bone Joint J 2024;106-B(1):93–98

Aims. The aim of this study was to analyse a group of patients with non-metastatic Ewing’s sarcoma at presentation and identify prognostic factors affecting the development of local recurrence, in order to assess the role of radiotherapy. Patients and Methods. A retrospective review of all patients with a Ewing’s sarcoma treated between 1980 and 2012 was carried out. Only those treated with chemotherapy followed by surgery and/or radiotherapy were included. Patients were grouped according to site (central or limb) for further analysis of the prognostic factors. Results. A total of 388 patients were included in the study. Of these, 60 (15%) developed local recurrence at a mean median of 27 months (. sd. 24, range 7 to 150) and the five-year local recurrence-free survival (5yrLRFS) was 83%. For central tumours, the size of the tumour and histological response to chemotherapy were found to be significant factors for local recurrence. For limb tumours, local recurrence was affected by intralesional and marginal resections, but not by the histological response to chemotherapy. Radiotherapy in those with a marginal resection reduced the risk of local recurrence (5yrLRFS: 96% versus 81%, p = 0.044). Conclusion. Local recurrence significantly affects the overall survival in patients with a Ewing’s sarcoma. For those with a tumour in a limb, radiotherapy reduced the risk of local recurrence, especially in those with a marginal margin of excision, but the effect in central tumours was less clear. Radiotherapy for those who have had a wide margin of resection does not reduce the risk of local recurrence, regardless of the histological response to chemotherapy. Cite this article: Bone Joint J 2018;100-B: 247–55

Aims. The purpose of this study was to review a large cohort of patients and further assess the correlation between the histological response to chemotherapy in patients with Ewing’s sarcoma with the overall (OS) and event-free survival (EFS). Patients and Methods. All patients treated for Ewing’s sarcoma between 1980 and 2012 were reviewed. Of these, 293 patients without metastases at the time of diagnosis and treated with chemotherapy and surgery were included. Patients were grouped according to the percentage of necrosis after chemotherapy: Group I: 0% to 50%, Group II: 51% to 99% and Group III: 100%. Results. The mean age at diagnosis was 16 years (1 to 62) and the mean follow-up was 9.1 years (six months to 32.6 years). The OS and EFS for the series were 75% and 65% at five years. There were significant differences in survival between the groups of necrosis: 0% to 50% (OS: 49% and EFS: 45% at five years, respectively) compared with 51% to 99% (OS: 72% and EFS: 59% at five years, respectively) and 100% (OS: 94% and EFS: 81% at five years, respectively) (p <  0.001). There were no significant differences in survival between patients treated between 1980 and 1989 compared with those treated between 1990 and 1999, and those treated between 2000 and 2012 (p = 0.55). Conclusion. Only patients with 100% necrosis after chemotherapy should be classified as having a good response to chemotherapy because they have significantly better rates of survival compared with those with any viable tumour in the surgical specimen. Cite this article: Bone Joint J 2016;98-B:1138–44

Aims. The aim of this study was to determine the risk of local recurrence and survival in patients with osteosarcoma based on the proximity of the tumour to the major vessels. Patients and Methods. A total of 226 patients with high-grade non-metastatic osteosarcoma in the limbs were investigated. Median age at diagnosis was 15 years (4 to 67) with the ratio of male to female patients being 1.5:1. The most common site of the tumour was the femur (n = 103) followed by tibia (n = 66). The vascular proximity was categorized based on the preoperative MRI after neoadjuvant chemotherapy into four types: type 1 > 5 mm; type 2 ≤ 5 mm, > 0 mm; type 3 attached; type 4 surrounded. Results. Limb salvage rate based on the proximity type was 92%, 88%, 51%, and 0% for types 1 to 4, respectively, and the overall survival at five years was 82%, 77%, 57%, and 67%, respectively (p < 0.001). Local recurrence rate in patients with limb-salvage surgery was 7%, 8%, and 22% for the types 1 to 3, respectively (p = 0.041), and local recurrence at the perivascular area was observed in 1% and 4% for type 2 and 3, respectively. The mean microscopic margin to the major vessels was 6.9 mm, 3.0 mm, and 1.4 mm for types 1 to 3, respectively. In type 3, local recurrence-free survival with limb salvage was significantly poorer compared with amputation (p = 0.025), while the latter offered no overall survival benefit. In this group of patients, factors such as good response to chemotherapy or limited vascular attachment to less than half circumference or longitudinal 10 mm reduced the risk of local recurrence. Conclusion. The proximity of osteosarcoma to major blood vessels is a poor prognostic factor for local control and survival. Amputation offers better local control for tumours attached to the blood vessels but does not improve survival. Limb salvage surgery offers similar local control if the tumour attachment to blood vessels is limited. Cite this article: Bone Joint J 2019;101-B:1024–1031

Aims. Bone metastasis ultimately occurs due to a complex multistep process, during which the interactions between cancer cells and bone microenvironment play important roles. Prior to colonization of the bone, cancer cells must succeed through a series of steps that will allow them to gain migratory and invasive properties; epithelial-to-mesenchymal transition (EMT) is known to be integral here. The aim of this study was to determine the effects of G protein subunit alpha Q (GNAQ) on the mechanisms underlying bone metastasis through EMT pathway. Methods. A total of 80 tissue samples from patients who were surgically treated during January 2012 to December 2014 were used in the present study. Comparative gene analysis revealed that the GNAQ was more frequently altered in metastatic bone lesions than in primary tumour sites in lung cancer patients. We investigated the effects of GNAQ on cell proliferation, migration, EMT, and stem cell transformation using lung cancer cells with GNAQ-knockdown. A xenograft mouse model tested the effect of GNAQ using micro-CT analyses and histological analyses. Results. GNAQ-knockdown showed down-regulation of tumour growth through mitogen-activated protein kinase (MAPK) signalling in lung cancer cells, but not increased apoptosis. We found that GNAQ-knockdown induced EMT and promoted invasiveness. GNAQ-knockdown cells injected into the bone marrow of murine tibia induced tumour growth and bone-to-lung metastasis, whereas it did not in control mice. Moreover, the knockdown of GNAQ enhanced cancer stem cell-like properties in lung cancer cells, which resulted in the development of resistance to chemotherapy. Conclusion. The present study reveals that the GNAQ-knockdown induced cancer stem cell-like properties. Cite this article: Bone Joint Res 2021;10(5):310–320