Aims. Due to the complex anatomy of the pelvis, limb-sparing resections of pelvic tumours achieving adequate surgical margins, can often be difficult. The advent of computer navigation has improved the precision of resection of these lesions, though there is little evidence comparing resection with or without the assistance of navigation. Our aim was to evaluate the efficacy of navigation-assisted surgery for the resection of pelvic bone tumours involving the posterior ilium and sacrum. . Patients and Methods. Using our prospectively updated institutional database, we conducted a retrospective case control study of 21 patients who underwent resection of the posterior ilium and sacrum, for the treatment of a primary sarcoma of bone, between 1987 and 2015. The resection was performed with the assistance of navigation in nine patients and without navigation in 12. We assessed the accuracy of navigation-assisted surgery, as defined by the surgical margin and how this affects the rate of local recurrence, the disease-free survival and the effects on peri-and post-operative morbidity. . Results. The mean age of the patients was 36.4 years (15 to 66). The mean size of the tumour was 10.9 cm. In the navigation-assisted group, the margin was wide in two patients (16.7%), marginal in six (66.7%) and wide-contaminated in one (11.1%) with no intralesional margin. In the non-navigated-assisted group; the margin was wide in two patients (16.7%), marginal in five (41.7%), intralesional in three (25.0%) and wide-contaminated in two (16.7%). Local recurrence occurred in two patients in the navigation-assisted group (22.2%) and six in the non-navigation-assisted group (50.0%). The disease-free survival was significantly better when operated with navigation-assistance (p = 0.048). The blood loss and operating time were less in the navigated-assisted group, as was the risk of a foot drop post-operatively. Conclusion . The introduction of navigation-assisted surgery for the resection of tumours of the posterior ilium and sacrum has increased the safety for the patients and allows for a better oncological outcome. . Cite this article: Bone Joint J 2017;99-B:261–6

Objectives. To assess the accuracy of patient-specific instruments (PSIs) versus standard manual technique and the precision of computer-assisted planning and PSI-guided osteotomies in pelvic tumour resection. Methods. CT scans were obtained from five female cadaveric pelvises. Five osteotomies were designed using Mimics software: sacroiliac, biplanar supra-acetabular, two parallel iliopubic and ischial. For cases of the left hemipelvis, PSIs were designed to guide standard oscillating saw osteotomies and later manufactured using 3D printing. Osteotomies were performed using the standard manual technique in cases of the right hemipelvis. Post-resection CT scans were quantitatively analysed. Student’s t-test and Mann–Whitney U test were used. Results. Compared with the manual technique, PSI-guided osteotomies improved accuracy by a mean 9.6 mm (p < 0.008) in the sacroiliac osteotomies, 6.2 mm (p < 0.008) and 5.8 mm (p < 0.032) in the biplanar supra-acetabular, 3 mm (p < 0.016) in the ischial and 2.2 mm (p < 0.032) and 2.6 mm (p < 0.008) in the parallel iliopubic osteotomies, with a mean linear deviation of 4.9 mm (p < 0.001) for all osteotomies. Of the manual osteotomies, 53% (n = 16) had a linear deviation > 5 mm and 27% (n = 8) were > 10 mm. In the PSI cases, deviations were 10% (n = 3) and 0 % (n = 0), respectively. For angular deviation from pre-operative plans, we observed a mean improvement of 7.06° (p < 0.001) in pitch and 2.94° (p < 0.001) in roll, comparing PSI and the standard manual technique. Conclusion. In an experimental study, computer-assisted planning and PSIs improved accuracy in pelvic tumour resections, bringing osteotomy results closer to the parameters set in pre-operative planning, as compared with standard manual techniques. Cite this article: A. Sallent, M. Vicente, M. M. Reverté, A. Lopez, A. Rodríguez-Baeza, M. Pérez-Domínguez, R. Velez. How 3D patient-specific instruments improve accuracy of pelvic bone tumour resection in a cadaveric study. Bone Joint Res 2017;6:577–583. DOI: 10.1302/2046-3758.610.BJR-2017-0094.R1

The February 2015 Hip & Pelvis Roundup. 360 . looks at: Hip arthroplasty in Down syndrome; Bulk femoral autograft successful in acetabular reconstruction; Arthroplasty follow-up: is the internet the solution?; Total hip arthroplasty following acetabular fracture; Salvage arthroplasty following failed hip internal fixation; Bone banking sensible financially and clinically; Allogenic blood transfusion in arthroplasty

The December 2015 Hip & Pelvis Roundup. 360 . looks at: Vitamin E infusion helpful in polyethylene; Hip replacement in fracture and arthritis; Non-surgical treatment for arthritis; Cost and approach in hip surgery; Who does well in FAI surgery?; AAOS Thromboembolism guidelines; Thromboprophylaxis and periprosthetic joint infection; Fluid collections not limited to metal-on-metal THR

The October 2015 Hip & Pelvis Roundup. 360 . looks at: Smoking and complications in arthroplasty; Smoking cessation beneficial in arthroplasty; Intermediate care and arthroplasty; Do we still need cell salvage?; Femoroacetabular impingement in the Japanese population; Trunnionosis or taperosis and geometry; Decontamination for staphylococcus aureus works!; Policeman or opportunity? Quality improvement with registries; Death rates higher in readmission to other hospitals

The October 2014 Hip & Pelvis Roundup. 360 . looks at: functional acetabular orientation; predicting re-admission following THR; metal ions and resurfacing; lipped liners increase stability; all anaesthetics equal in hip fracture surgery; revision hip surgery in very young patients; and uncemented hips

The April 2014 Hip & Pelvis Roundup. 360 . looks at: Recent arthroplasty and flight; whether that squeak could be a fracture; diagnosing early infected hip replacement; impaction grafting at a decade; whether squeaking is more common than previously thought; femoral offset associated with post THR outcomes; and periprosthetic fracture stabilisation

High energy fractures of the pelvis are a challenging problem both in the immediate post-injury phase and later when definitive fixation is undertaken. No single management algorithm can be applied because of associated injuries and the wide variety of trauma systems that have evolved around the world. Initial management is aimed at saving life and this is most likely to be achieved with an approach that seeks to identify and treat life-threatening injuries in order of priority. Early mortality after a pelvic fracture is most commonly due to major haemorrhage or catastrophic brain injury. In this article we review the role of pelvic binders, angiographic embolisation, pelvic packing, early internal fixation and blood transfusion with regard to controlling haemorrhage. Definitive fixation seeks to prevent deformity and reduce complications. We believe this should be undertaken by specialist surgeons in a hospital resourced, equipped and staffed to manage the whole spectrum of major trauma. We describe the most common modes of internal fixation by injury type and review the factors that influence delayed mortality, adverse functional outcome, sexual dysfunction and venous thromboembolism

The Unified Classification System (UCS) emphasises the key principles in the assessment and management of peri-prosthetic fractures complicating partial or total joint replacement. We tested the inter- and intra-observer agreement for the UCS as applied to the pelvis and femur using 20 examples of peri-prosthetic fracture in 17 patients. Each subtype of the UCS was represented by at least one case. Specialist orthopaedic surgeons (experts) and orthopaedic residents (pre-experts) assessed reliability on two separate occasions. For the pelvis, the UCS showed inter-observer agreement of 0.837 (95% confidence intervals (CI) 0.798 to 0.876) for the experts and 0.728 (95% CI 0.689 to 0.767) for the pre-experts. The intra-observer agreement for the experts was 0.861 (95% CI 0.760 to 0.963) and 0.803 (95% 0.688 to 0.918) for the pre-experts. For the femur, the UCS showed an inter-observer kappa value of 0.805 (95% CI 0.765 to 0.845) for the experts and a value of 0.732 (95% CI 0.690 to 0.773) for the pre-experts. The intra-observer agreement was 0.920 (95% CI 0.867 to 0.973) for the experts, and 0.772 (95% CI 0.652 to 0.892) for the pre-experts. This corresponds to a substantial and ‘almost perfect’ inter- and intra-observer agreement for the UCS for peri-prosthetic fractures of the pelvis and femur. We hope that unifying the terminology of these injuries will assist in their assessment, treatment and outcome. Cite this article: Bone Joint J 2014;96-B:1472–7

1. The strength of the pelvic arch depends on the integrity of the anterior interpubic ligament, whose strength has been demonstrated by dissections. Once that ligament is divided the sacro-iliac ligaments offer little resistance to opening out of the pelvis. 2. The structure of the pelvis and hips is compared to an arcade formed by a central and two lateral arches. The weight of the trunk is transmitted to the lower limbs through this arcade. 3. Fractures of the pelvis are classified according to the mechanism of production. The case for anatomical reposition and internal fixation is stated, and case histories are given to illustrate the disabilities due to persistent deformity. 4. Reduction can be achieved as late as two or three weeks after injury. However, if early operation for visceral injury is necessary, there is a strong case for combining this with open reduction and fixation. In some cases the patient's general condition may preclude such procedures, but more usually the additional manipulations cause little additional operative shock and are fully justified by the subsequent increased comfort of the patient and the greater ease of nursing

The April 2015 Hip & Pelvis Roundup. 360 . looks at: Goal-directed fluid therapy in hip fracture; Liberal blood transfusion no benefit in the longer term; Repeated measures: increased accuracy or compounded errors?; Peri-acetabular osteotomy safer than perhaps thought?; Obesity and peri-acetabular osteotomy: poor bedfellows; Stress fracture in peri-acetabular osteotomy; Infection and tantalum implants; Highly crosslinked polyethylene really does work

The December 2014 Hip & Pelvis Roundup. 360 . looks at: Sports and total hips; topical tranexamic acid and blood conservation in hip replacement; blind spots and biases in hip research; no recurrence in cam lesions at two years; to drain or not to drain?; sonication and diagnosis of implant associated infection; and biomarkers and periprosthetic infection

Objectives. The clinical utility of routine cross sectional imaging of the abdomen and pelvis in the screening and surveillance of patients with primary soft-tissue sarcoma of the extremities for metastatic disease is controversial, based on its questionable yield paired with concerns regarding the risks of radiation exposure, cost, and morbidity resulting from false positive findings. Methods. Through retrospective review of 140 patients of all ages (mean 53 years; 2 to 88) diagnosed with soft-tissue sarcoma of the extremity with a mean follow-up of 33 months (0 to 291), we sought to determine the overall incidence of isolated abdominopelvic metastases, their temporal relationship to chest involvement, the rate of false positives, and to identify disparate rates of metastases based on sarcoma subtype. Results. A total of four patients (2.9%) exhibited isolated abdominopelvic metastatic disease during the surveillance period. In all cases of concomitant chest and abdominopelvic disease, chest involvement preceded abominopelvic involvement. There was a significant false positive rate requiring invasive workup. Conclusions. In the setting of a relative paucity of evidence concerning a rare disease process and in difference to recently published investigations, we add a clinical cohort not supportive of routine cross sectional imaging of the abdomen and pelvis. Cite this article: Bone Joint Res 2015;4:45–9

The August 2014 Hip & Pelvis Roundup. 360 . looks at: Serial MRIs best for pseudotumour surveillance; Is ultrasound good enough for MOM follow-up?; Does weight loss in obese patients help?; Measuring acetabular anteversion on plain films; Two-stage one-stage too many in fungal hip revisions? and 35 is the magic number in arthroplasty

The June 2014 Hip & Pelvis Roundup. 360 . looks at: Modular femoral necks: early signs are not good; is corrosion to blame for modular neck failures; metal-on-metal is not quite a closed book; no excess failures in fixation of displaced femoral neck fractures; noise no problem in hip replacement; heterotopic ossification after hip arthroscopy: are NSAIDs the answer?; thrombotic and bleeding events surprisingly low in total joint replacement; and the elephant in the room: complications and surgical volume

The aim of this retrospective cohort study was to identify any difference in femoral offset as measured on pre-operative anteroposterior (AP) radiographs of the pelvis, AP radiographs of the hip and corresponding CT scans in a consecutive series of 100 patients with primary end-stage osteoarthritis of the hip (43 men and 57 women with a mean age of 61 years (45 to 74) and a mean body mass index of 28 kg/m. 2. (20 to 45)). Patients were positioned according to a standardised protocol to achieve reproducible projection and all images were calibrated. Inter- and intra-observer reliability was evaluated and agreement between methods was assessed using Bland-Altman plots. In the entire cohort, the mean femoral offset was 39.0 mm (95% confidence interval (CI) 37.4 to 40.6) on radiographs of the pelvis, 44.0 mm (95% CI 42.4 to 45.6) on radiographs of the hip and 44.7 mm (95% CI 43.5 to 45.9) on CT scans. AP radiographs of the pelvis underestimated femoral offset by 13% when compared with CT (p < 0.001). No difference in mean femoral offset was seen between AP radiographs of the hip and CT (p = 0.191). Our results suggest that femoral offset is significantly underestimated on AP radiographs of the pelvis but can be reliably and accurately assessed on AP radiographs of the hip in patients with primary end-stage hip osteoarthritis. We, therefore, recommend that additional AP radiographs of the hip are obtained routinely for the pre-operative assessment of femoral offset when templating before total hip replacement

The December 2013 Hip & Pelvis Roundup. 360 . looks at: Enhanced recovery works; Acetabular placement; Exercise better than rest in osteoarthritis patients; if Birmingham hip resurfacing is immune from pseudotumour; HIV and arthroplasty; Labral tears revisited; Prophylactic surgery for FAI; and Ceramics and impaction grafting