Introduction. Even in localized collapse due to osteonecrosis of the femoral head, a femoral head can be preserved by rotational osteotomy. In addition to anterior rotation, originally described by Sugioka, much more correction can be obtained by posterior rotation. But, transtrochanteric rotational osteotomy needs rather extensive soft tissue release, such as complete capsulotomy and resection of short external rotators and psoas tendons. Many patients tend to complain about the leg length discrepancy and limp due to varus change. We found soft tissue resection and limb shortening could be minimized by doing the osteotomy at the femur neck rather than the trochanteric area following the technique of surgical dislocation. It needs careful dissection of the posterior retinacular artery to preserve circulation to the femoral head. Methods. We have performed 17 cases (14 cases were in men and 3 cases were in women), and average patient age was 45 years old. Osteotomy was applied to cases with collapse or large necrotic region that seemed to be fail by core decompression. All cases showed collapse except one (ARCO 2-B) and 6 cases were ARCO 3-A, 5 cases were ARCO 3-B, 4 cases were ARCO 3-C and one case was ARCO stage 4. Seven cases were rotated anteriorly, and ten cases were rotated posteriorly. Amount of rotation was 63 to 170 degrees in posterior rotation (mean 100.8 degrees) and mean 48 degrees in anterior rotation. The size of the necrotic area was 301 degrees according to the Koo method (combined necrotic angle in mid-coronal and mid-saggital MRI scan). Results. Harris hip scores were improved from 62 to 88 points and VAS was from 8.4 to 2.6 in 13 cases. Conversion to THA was done in 4 cases (23.5%) as pain was persisting and there was one more failed case which was lost to follow-up. Another 2 cases showed insufficient circulation in bone SPECT, but no symptoms until recently. Problems with fixatives were in 4 cases and one case had heterotopic ossification without symptom. Conclusion. In conclusion, the outcome of the operation could be identified much earlier than other procedures. 12 cases (58.8%) showed satisfactory results and 2 cases were in observation due to insufficient circulation, and 5 cases (29.4%) failed. The operative technique will be revised and we are expecting better results

Proximal femur fractures are common in the elderly population. The aim of this study was to determine the relationship between fracture type and proximal femoral geometric parameters.

We retrospectively studied the electronic medical records of 85 elderly patients over 60 years of age who were admitted to the orthopedic department with hip fractures between January 2016 and January 2018 in a training and research hospital in Turkey. Age, fracture site, gender, implant type and proximal femoral geometry parameters (neck shaft angle [NSA], center edge angle [CEA], femoral head diameter [FHD], femoral neck diameter [FND], femoral neck axial length [FNAL], hip axial length [HAL], and femoral shaft diameter [FSD]) were recorded. Patients with femoral neck fractures and femur intertrochanteric fractures were divided into two groups. The relationship between proximal femoral geometric parameters and fracture types was examined. SPSS 25.0 (IBM Corparation, Armonk, New York, United States) program was used to analyze the variables. Independent samples t test was used to compare the fracture types according to NSA, FHD, FND and FSD variables.

A statistically significant difference was found in FSD (p=0,002) and age (p=0,019). FSD and age were found to be greater in intertrochanteric fractures than neck fractures. Gender, site, CEA, FNAL, HAL, NSA, FHD and FND parametres were not significantly different.

In the literature, it is seen that different results have been reached in different studies. In a study conducted in the Chinese population, a significant difference was found between the two groups in NSA, CEA and FNAL measurements. In a study conducted in the Korean population, a significant difference was found only in NSA measurements. The FSD is generally associated with bone mineral densitometry in the literature and has been shown to be a risk factor for fracture formation. However, a study showing that there is a relationship between FSD and fracture type is not available in the literature.

In this study; FSD was found to be higher in intertrochanteric fractures (p = 0.002). However, for the clinical significance of this difference, we think that larger patient series and biomechanical studies are needed.

Summary Statement. This work features a new approach to overcome drawbacks of commercial calcium phosphate cements in terms of application by on-site preparation and bone ingrowth by introduction of macropores in the material using a hydrofluoroalkane based aerosol foam. Introduction. The application of calcium phosphate bone cements (CPCs) into a void for example of an osteoporotic bone is very difficult as the cement paste is made outside the application site and subsequently applied into the damaged bone. A common drawback of especially apatitic cements is a very low resorption rate due to small pore size Therefore different approaches have been described to add macropores into the cement. 2. , leading to bone ingrowth and tissue penetration. The aim of this project is the use of two separate formulations in pressurised systems – a suspension and an emulsion – which can be mixed in a specially developed device and can be applied easily and efficiently into a bone directly during surgery leading to a self-hardening macro porous CPC foam. The intention is to fill voids in osteoporotic bones to ensure stability for implants like e.g. screws for femur neck fractures. An increased stability for implants can allow the possibility of a less invasive femur neck preserving therapy in contrast to a femur neck replacement. Other indications for such foam (i.e. kyphoplasty) are under evaluation. Methods. As suggested above two separate formulations for the components are developed to prevent premature hardening. Hydrofluoroalkanes were preferred as propellants to propane, butane or isobutane, due to their superior safety profile. The hardener component was formulated as propellant-in-water emulsion. Several parentally approved emulsifiers (e.g. Poloxamer 188) were tested in view of solubility at the given salt and binder concentration. The stability of resulting emulsions in pressurised containers, the corresponding foams as well as the foam expansion volume was analyzed. Porous hydroxyapatite is formed after addition of tetra-calciumphosphate, di-calciumphosphate dihydrate and tri-sodiumcitrat dehydrate incorporated in the suspension component. To overcome quick sedimentation of these solids, particle size was reduced by dry or non-aqueous wet milling, respectively. Changes in particle size distribution and enthalpy changes during processes were analyzed. Hardening properties of both components were tested particularly with regard to compressive strength. In order to apply the components, a suitable application system was developed and the hardened product analyzed using x-ray diffraction. Results. The optimised Ca. 2+. /(PO. 4. ). 3−. component is a submicron-sized suspension in a mixture of ethanol and HFA 134a. The development of the suspension led to new knowledge with regard to milling effects on the Ca. 2+. /(PO. 4. ). 3−. components. The optimised hardener component contains an aqueous solution of sodium phosphates, Povidone 90 and Poloxamer 188 emulsified in HFA 227. Both components are formulated in pressurised cans. Discussion/Conclusion. A two component bone foam for stabilisation in osteoporotic bones including a new mixing / application system, which allows actuation of the components and leads to a hardening process that results in hydroxyapatite in a suitable test setup, was developed. The new application system. Further steps i.e. proof of concept (in-vitro and in-vivo) are being taken