Radiation dose and magnification in pelvic X-ray: EOS™ imaging system versus plain radiographs.

BACKGROUND: In plain pelvic X-ray, magnification makes measurement unreliable. The EOS™ (EOS Imaging, Paris France) imaging system is reputed to reproduce patient anatomy exactly, with a lower radiation dose. This, however, has not been assessed according to patient weight, although both magnification and irradiation are known to vary with weight. We therefore conducted a prospective comparative study, to compare: (1) image magnification and (2) radiation dose between the EOS imaging system and plain X-ray. HYPOTHESIS: The EOS imaging system reproduces patient anatomy exactly, regardless of weight, unlike plain X-ray. MATERIAL AND METHOD: A single-center comparative study of plain pelvic X-ray and 2D EOS radiography was performed in 183 patients: 186 arthroplasties; 104 male, 81 female; mean age 61.3±13.7years (range, 24-87years). Magnification and radiation dose (dose-area product [DAP]) were compared between the two systems in 186 hips in patients with a mean body-mass index (BMI) of 27.1±5.3kg/m2 (range, 17.6-42.3kg/m2), including 7 with morbid obesity. RESULTS: Mean magnification was zero using the EOS system, regardless of patient weight, compared to 1.15±0.05 (range, 1-1.32) on plain X-ray (P<10-5). In patients with BMI<25, mean magnification on plain X-ray was 1.15±0.05 (range, 1-1.25) and, in patients with morbid obesity, 1.22±0.06 (range, 1.18-1.32). The mean radiation dose was 8.19±2.63dGy/cm2 (range, 1.77-14.24) with the EOS system, versus 19.38±12.37dGy/cm2 (range, 4.77-81.75) with plain X-ray (P<10-4). For BMI >40, mean radiation dose was 9.36±2.57dGy/cm2 (range, 7.4-14.2) with the EOS system, versus 44.76±22.21 (range, 25.2-81.7) with plain X-ray. Radiation dose increased by 0.20dGy with each extra BMI point for the EOS system, versus 0.74dGy for plain X-ray. CONCLUSION: Magnification did not vary with patient weight using the EOS system, unlike plain X-ray, and radiation dose was 2.5-fold lower. LEVEL OF EVIDENCE: 3, prospective case-control study.

Proximal femoral fractures in centenarians. A retrospective analysis of 39 patients.

BACKGROUND: A corollary of the current population ageing in France is an increase in proximal femoral fractures (PFFs), particularly among centenarians. The outcomes of PFFs in centenarians in France are unknown. We therefore conducted a retrospective study of centenarians with PFFs both to assess: (1) assess clinical outcomes according to geriatric and trauma scores, (2) and to determine whether routine surgery is warranted. HYPOTHESIS: Morbidity and mortality in a single-centre cohort of centenarians with surgically treated PFFs are consistent with previous reports. MATERIAL AND METHOD: We retrospectively reviewed the data of 33 women and 6 men aged 100 years or over who were treated surgically for PFFs at a single-centre between 2008 and 2014. Of the 39 patients, 15 were living at home and 24 in an institution at the time of the injury. Mean (range) values were 3.30 (0-7) for the Parker Mobility Score, 5.84 (0-12) for the Katz index, and 7.46 (2-12) for the Mini Nutritional Assessment (MNA). Mean time from injury to surgery was 1.7 days (0-12). The 26 extra-capsular fractures were managed by internal fixation and the 13 intra-capsular fractures by hip arthroplasty (n=12) or screw fixation (n=1). RESULTS: After a mean follow-up of 23±14 months (6-60 months), 29 patients had died, including 3 within 48h, 10 within 3 months, and 15 within 1 year. Sequential mortality rates were 33.3% within the first 3 months, 26.9% from months 4 to 9, and 42.2% within the first year. Early dislocation occurred in 3 patients and surgical-site infection in 2 patients. Other complications were heart failure (n=1), confusional state (n=2), pneumonia (n=2), and pyelonephritis (n=2). DISCUSSION: A PubMed search identified five studies of PFFs in more than 10 centenarians, of which only 2 provided detailed information on postoperative general and local morbidity related to the surgical treatment. Our hypothesis was confirmed for 3-month and 1-year mortality rates, which were at the lower ends of previously reported ranges. Local complications related directly to surgery were considerably more common in our study. PFFs in centenarians carry a high risk of death. Despite the absence of a control group, our data support surgery as the best treatment option. LEVEL OF EVIDENCE: IV, retrospective study.