Purpose The Cobb angle as an objective measure is used to determine the progression of deformity, and is the basis in the planning of conservative and surgical treatment. However, studies have shown that the Cobb angle has two limitations: an inter- and intraobserver variability of the measurement is approximately 3–5 degrees, and high variability regarding the definition of the end vertebra. Scoliosis is a three-dimensional (3D) pathology, and 3D pathologies cannot be completely assessed by two-dimensional (2D) methods, like 2D radiography. The objective of this study was to determine the intraobserver and interobserver reliability of end vertebra definition and Cobb angle measurement using X-rays and 3D computer tomography (CT) reconstructions in scoliotic spines. Methods To assess interoberver variation the Cobb angle and the end vertebra were assessed by five observers in 55 patients using X-rays and 3D CT reconstructions. Definition of end vertebra and measurement of the Cobb angle was repeated two times with a three-week interval. Intraclass correlation coefficients (ICC) were used to determine the interobserver and intraobserver reliabilities. 95% prediction limits were provided for measurement errors. Results Intraclass correlation coefficient (ICC) showed excellent reliability for both methods. The measured Cobb angle was on average 9.2 degrees larger in the 3D CT group (72.8°, range 30–144) than on 2D radiography (63.6°, range 24–152). Conclusions In scoliosis treatment it is very essential to determine the curve magnitude, which is larger in a 3D measurement compared to 2D radiography.

Background: The aim of the current study was to evaluate the impact of the coronavirus disease (COVID-19) pandemic on musculoskeletal tumor service by conducting an online survey of physicians. Methods: The survey was conducted among the members of the ISOLS (International Society of Limb Salvage) and the EMSOS (European Musculo-Skeletal Oncology Society). The survey consisted of 20 questions (single, multiple-response, ranked): origin and surgical experience of the participant (four questions), potential disruption of healthcare (12 questions), and influence of the COVID-19 pandemic on the particular physician (four questions). A matrix with four different response options was created for the particular surgical procedures). Results: One hundred forty-nine physicians from five continents completed the survey. Of the respondents, 20.1% and 20.7% stated that surgery for life-threatening sarcomas were stopped or delayed, respectively. Even when the malignancy was expected to involve infiltration of a neurovascular bundle or fracture of a bone, still 13.8% and 14.7% of the respondents, respectively, stated that surgery was not performed. In cases of pending fractures of bone tumors, 37.5 to 46.2% of operations were canceled. Conclusion: The SARS-CoV-2 pandemic caused a significant reduction in healthcare (surgery, radiotherapy, chemotherapy) for malignancies of the musculoskeletal system. Delaying or stopping these treatments is life-threatening or can cause severe morbidity, pain, and loss of function. Although the coronavirus disease causes severe medical complications, serious collateral damage including death due to delayed or untreated sarcomas should be avoided.

Background and purpose Correct positioning of the acetabular component is important in total hip arthroplasty (THA). We evaluated the effect of an imageless navigation system on the accuracy of cup positioning using a minimally invasive direct anterior approach. Methods Hip replacements were performed in 44 cadaveric hips (22 cadavers) that were divided randomly into 2 groups. In the study group, THA was performed using an imageless navigation system. In the control group, no navigation system was used. CT scans were taken postoperatively. Using 3D reconstructions, the cup position was determined in relation to the frontal pelvic plane. The goal was to place each cup at 45° of inclination and 20° of anteversion, as recommended by the manufacturer. Results In the navigated group, there was a statistically significantly smaller range of deviation from the target angles of inclination and anteversion relative to the control group. Interpretation We conclude that imageless navigation improves the accuracy of cup placement in minimally invasive THA using the direct anterior approach.

A primary Echinococcus granulosus infection of the spine involving the vertebrae T8 and T9 of a 6-year-old child was treated elsewhere by thoracotomy, partial corporectomy, multiple laminectomies and uninstrumented fusion. Owing to inappropriate stabilization, severe deformity developed secondary to these surgeries. X-rays, CT and MRI scans of the spine revealed a severe thoracic kyphoscoliosis of more than 100° (Fig. 1 ) and recurrence of Echinococcus granulosus infection. The intraspinal cyst formation was located between the stretched dural sac and the vertebral bodies of the kyphotic apex causing significant compression of the cord (Figs. 2 , 3 , 4 ). A progressive neurologic deficit was reported by the patient. At the time of referral, the patient was wheelchair bound and unable to walk by herself (Frankel Grade C). Standard antiinfectious therapy of Echinococcus granulosus requires a minimum treatment period of 3 months. This should be done before any surgical intervention because in case of a rupture of an active cyst, the delivered lipoprotein antigens of the parasite may cause a potentially lethal anaphylactic shock. Owing to the critical neurological status, we decided to perform surgery without full length preoperative antiinfectious therapy. Surgical treatment consisted in posterior vertebral column resection technique with an extensive bilateral costotransversectomy over three levels, re-decompression with cyst excision around the apex and multilevel corporectomy of the apex of the deformity. Stabilisation and correction of the spinal deformity were done by insertion of a vertebral body replacement cage anteriorly and posterior shortening by compression and by a multisegmental pedicle screw construct. After the surgery, antihelminthic therapy was continued. The patients neurological deficits resolved quickly: 4 weeks after surgery, the patient had Frankel Grade D and was ambulatory without any assistance. After an 18-month follow-up, the patient is free of recurrence of infection and free of neurologically deficits (Frankel E). This case demonstrates that inappropriate treatment—partial resection of the cyst, inappropriate anterior stabilization and posterior multilevel laminectomies without posterior stabilization—may lead to severe progressive kyphoscoliotic deformity and recurrence of infection, both leading to significant neurological injury presenting as a very difficult to treat pathology. Fig. 1 X-rays of the patient showing a kyhoscoliotic deformity. a ap view, b lateral view Fig. 2 CT reconstruction of the whole spine showing the apex of the deformity is located in the area of the previous surgeries Fig. 3 Sagittal CT-cut showing the bone bloc at the apex with a translation deformity Fig. 4 Sagittal T2-weighted MRI image showing the cystic formation at the apex

Background: Periprosthetic femoral fractures (PPF) are a devastating complication after total hip arthroplasty (THA). Both trauma and adult reconstruction surgeons or combined teams treat these fractures following management algorithms. The aim of this study is to investigate the current treatment of PPF by members of the European Hip Society (EHS). Methods: An online survey of the members of the European Hip Society (EHS) was conducted. 20 cases of periprosthetic fracture were presented and surgeons were asked to answer questions regarding classification, treatment and postoperative treatment protocol. Results: A total of 132 (130 male; 2 female) EHS members responded. Mean years in surgical practice was 18.8 (min. 1 year; max. 50 years). The preferred surgical method was combined open reduction and internal fixation (ORIF) (30.3%) for AG fractures, ORIF with cables (30.4%) for AL fractures, combined ORIF (cable and plate) for B1 fractures (49.2%), stem revision with cables for B2 fractures (73.1%), stem revision with cables for B3 (55.9%) fractures and combined ORIF (cable and plate: 55.5%) for C fractures. Surprisingly, 10.8% suggested various stem revision techniques for B1 and 17.4% for C fractures. Strong variations were observed regarding postoperative weight-bearing protocol. Conclusions: A strong consensus was found for the choice of conservative or surgical treatment of the different PPF types according to the Vancouver Classification. Various stem revision techniques were the preferred surgical techniques for Vancouver B2 (91.2%) and B3 (88.6%) fractures. However, for postoperative weight-bearing, when the ORIF technique was used, a significant variation of protocols was found.