The most important outcome predictor of Legg-Calvé-Perthes disease (LCPD) is the shape of the healed femoral head. However, the deformity of the femoral head is currently evaluated by non-reproducible, categorical, and qualitative classifications. In this regard, recent advances in computer vision might provide the opportunity to automatically detect and delineate the outlines of bone in radiographic images for calculating a continuous measure of femoral head deformity. This study aimed to construct a pipeline for accurately detecting and delineating the
Summary Statement. A population based finite element study that accounts for subject-specific morphology, density and load variations, suggests that osteoporosis does not markedly lower the mechanical compliance of the
The purpose of our study was to identify possible risk factors of patients with GCT of the long bones after curettage and packing the bone cavity with bone cement or bone allografts. We retrospectively reviewed the records of 249 patients with GCT of the limbs treated at Musculoskeletal Oncology Department of our institution between 1990 and 2013, confirmed histologically and recorded in the Bone Tumor Registry. We reviewed 219 cases located in the lower limb and 30 of the upper limb. This series includes 135 females and 114 males, with mean age 32 years (ranging 5 to 80 yrs). According to Campanacci's grading system, 190 cases were stage 2, 48 cases stage 3, and 11 cases stage 1. Treatment was curettage (intralesional surgery). Local adjuvants, such as phenol and cement, were used in 185 cases; whereas in the remaining 64 cases the residual cavity was filled with allografts or autografts only. Oncological outcome shows 203 patients alive and continuously disease-free (CDF), 41 patients NED1 after treatment of local recurrence (LR), 2 patients NED1 after treatment of lung metastases, 2 AWD with lung metastases. One patient died of unrelated causes (DOD). LR rate was 15.3% (38 pts). Lung metastases rate was 1.6% (4 pts). In patients treated by curettage and cement (185 cases) LR was 12% (22 pts). Conversely, in patients treated curettage and bone allografts it was higher (16/64 cases), with an incidence of 25% of cases (p=0.004). Oncological complications seemed to be related with site, more frequently occurring in the
We have evaluated bone-marrow activity in the
We implanted titanium and carbon fibre-reinforced plastic (CFRP) femoral prostheses of the same dimensions into five prosthetic femora. An abductor jig was attached and a 1 kN load applied. This was repeated with five control femora. Digital image correlation was used to give a detailed two-dimensional strain map of the medial cortex of the
The high risk and the associated high mortality of secondary, contralateral hip fractures [1,2] could justify internal, invasive prophylactic reinforcement of the osteoporotic
In a retrospective study, FE-based bone strength from CT data showed a greater ability than aBMD to discriminate proximal femur fractures versus controls. Personalised Finite Element (FE) models from Computed Tomography (CT) data are superior to bone mineral density (BMD) in predicting proximal femoral strength Summary Statement
Introduction
We aimed to evaluate the precision and longitudinal sensitivity of measurement of bone mineral density (BMD) in the pelvis and to determine the effect of bone cement on the measurement of BMD in femoral regions of interest (ROI) after total hip arthroplasty (THA). A series of 29 patients had duplicate dual-energy x-ray absorptiometry (DXA) scans of the hip within 13 months of THA. Pelvic analyses using 3- and 4-ROI models gave a coefficient of variation (CV) of 2.5% to 3.6% and of 2.5% to 4.8%, respectively. Repeat scans in 17 subjects one year later showed a significant change in BMD in three regions using the 4-ROI model, compared with change in only one region with the 3-ROI model (p <
0.05). Manual exclusion of cement from femoral ROIs increased the net CV from 1.6% to 3.6% (p = 0.001), and decreased the measured BMD by 20% (t = 12.1, p <
0.001). Studies of two cement phantoms in vitro showed a small downward drift in bone cement BMD giving a measurement error of less than 0.03 g/cm2/year associated with inclusion of cement in femoral ROIs. Changes in pelvic periprosthetic BMD are best detected using a 4-ROI model. Analysis of femoral ROI is more precise without exclusion of cement although an awareness of its effect on the measurement of the BMD is needed.
Subtle variations in hip morphology associate with risk of hip osteoarthritis (OA). However, validated accurate methods to quantitate hip morphology using plain radiography are lacking. We have developed a Matlab-based software-tool (SHIPs) that measures 19 OA-associated morphological-parameters of the hip using a PACS pelvic radiograph. In this study we evaluated the accuracy and repeatability of the method. Software accuracy was assessed by firstly measuring the linear ratio of 2 fixed distances and several angles against a gold-standard test radiograph, and secondly by repeated measurements on a simulated AP radiograph of the pelvis (reformatted from CT-data) that was digitally rotated about 3-axes to determine the error associated with pelvic mal-positioning. Repeatability was assessed using 30-AP Pelvic radiographs analysed twice (intra-observer), by 2 readers (inter-observer), and finally, using 2 pelvic radiographs taken in 23 subjects (n=46 radiographs) taken same day after re-positioning (short-term clinical-practice variability), and was expressed as coefficient of variation (CV%).Introduction
Methods
Six pairs of human cadaver femora were divided equally into two groups one of which received a non-cemented reference implant and the other a very short non-dependent experimental implant. Thirteen strain-gauge rosettes were attached to the external surface of each specimen and, during application of combined axial and torsional loads to the femoral head, the strains in both groups were measured. After the insertion of a non-cemented femoral component, the normal pattern of a progressive proximal-to-distal increase in strains was similar to that in the intact femur and the strain was maximum near the tip of the prosthesis. On the medial and lateral aspects of the
This study compared the pullout forces of the initial implantation and the “cement-in-cement” revision technique for short and standard-length (125 mm vs. 150 mm) Exeter. ®. V40 femoral stems used in total hip arthroplasty (THA). The idea that the pullout force for a double taper slip stem is relative to the force applied to the femur and that “cement-in-cement” revision provides the same reproduction of force. A total sample size of 15 femoral stems were tested (Short, n = 6 and Standard, n = 9). 3D printed fixtures for repeatable sample preparation were used to minimize variance during testing. To promote stem subsidence and to simulate an in vivo environment, the samples were placed in an incubator at 37°C at 100% humidity and experienced a constant compressive loading of 1335 N for 14 days. The samples underwent a displacement-controlled pullout test. After the initial pullout test, “cement-in-cement” revision will be performed and tested similar to the initial implantation to observe the efficacy of the revision technique. To compare the pullout forces between the two groups, a Kruskal-Wallis test using a significance level of 0.05 was conducted. The mean maximum pullout force for the short and standard-length femoral stems were 3939 ± 1178 N and 5078 ± 1168 N, respectively. The Kruskal-Wallis test determined no statistically significant difference between the two groups for the initial implantation (p = 0.13). The “cement-in-cement” revision pullout force will be conducted in future testing. This study demonstrated the potential use of short stem designs for THA as it provides similar levels of fixation as the standard-length femoral stem. The potential benefits for using a short stem design would be providing similar load transfer to the
This study aims to assess the fracture mechanics of type-2 diabetic (T2D) femoral bone using innovative site-specific tests, whilst also examining the cortical and trabecular bone microarchitecture from various regions using micro-computed tomography (CT) of the femur as the disease progresses. Male [Zucker Diabetic Fatty (ZDF: fa/fa) (T2D) and Zucker Lean (ZL: fa/+) (Control)] rats were euthanized at 12-weeks of age, thereafter, right and left femora were dissected (Right femora: n = 6, per age, per condition; Left femora: n=8-9, per age, per condition). Right femurs were notched in the posterior of the midshaft. Micro-CT was used to scan the
According to the latest report from the German Arthroplasty Registry, aseptic loosening is the primary cause of implant failure following primary hip arthroplasty. Osteolysis of the
Total hip arthroplasty (THA) outcome in patients with osteonecrosis of the femoral head ONFH) are excellent, however, there is controversy when compared with those in patients with osteoarthritis (OA). Reduced mineralization capacity of osteoblasts of the
Hydroxyapatite-coated standard anatomical and customised femoral stems are designed to transmit load to the metaphyseal part of the
Introduction and Objective. Heterotopic ossification is the formation of extraskeletal mineralized tissue commonly associated with either trauma or surgery. While several mouse models have been developed to better characterize the pathologic progression of HO, no model currently exists to study HO of the hip, the most common location of acquired HO in patients. Owing to the unique biological mechanisms underpinning the formation of HO in different tissues, we sought to develop a model to study the post-surgical HO of the hip. Materials and Methods. Wild-type mice C57BL/6J mice were used to study the procedure outcomes, while Pdgfra-CreERT2;mT/mG and Scx-GFP reporter animals were used for the lineage tracing experiments (total n=16 animals, male, 12 weeks old). An anterolateral approach to the hip was performed. Briefly, a 2 cm incision was made centered on the great trochanter and directed proximal to the iliac crest and distally over the lateral shaft of the femur. The joint was then reached following the intermuscular plane between the rectus femoris and gluteus medius muscles. After the joint was exposed, the articular cartilage was removed using a micropower drill with a 1.2 mm reamer. The medius gluteus and superficial fascia were then re-approximated with Vicryl 5-0 suture (Ethicon Inc, Somerville, NJ) and skin was then closed with Ethilon 5-0 suture (Ethicon Inc). Live high resolution XR imaging was performed every 2 wks to assess the skeletal tissues (Faxitron Bioptics, Tucson, AZ). The images were then scored using the Brooker classification. Ex-vivo microCT was conducted using a Skyscan 1275 scanner (Bruker-MicroCT, Kontich, Belgium). 3D reconstruction and analysis was performed using Dragonfly (ORS Inc., Montreal, Canada). For the histological analysis of specimens, Hematoxylin and Eosin (H&E), modified Goldner's Trichrome (GMT) stainings were performed. Reporter activity was assessed using fluorescent imaging. Results. Substantial periarticular heterotopic bone was seen in all cases. A periosteal reaction and an initial formation of calcified tissue within the soft tissue was apparent starting from 4 wks after surgery. By XR, progressive bone formation was observed within the periosteum and intermuscular planes during the subsequent 8 weeks. Stage 1 HO was observed in 12.5% of cases, stage 2 in 62.5% of cases, and stage 3 HO in 25% of cases. 3D microCT reconstructions of the treated hip joints demonstrated significant de novo heterotopic bone in several location which phenocopy human disease. Heterotopic bone was observed in an intracapsular location, periosteal location involving the iliac bone and
Infected non-unions of proximal femoral fractures are difficult to treat. If debridement and revision fixation is unsuccessful, staged revision arthroplasty may be required. Non-viable tissue must be resected, coupled with the introduction of an antibiotic-eluting temporary spacer prior to definitive reconstruction. Definitive tissue microbiological diagnosis and targeted antibiotic therapy are required. In cases of significant proximal femoral bone loss, spacing options are limited. We present a case of a bisphosphonate-induced subtrochanteric fracture that progressed to infected non-union. Despite multiple washouts and two revision fixations, the infection remained active with an unfavourable antibiogram. The patient required staged revision arthroplasty including a proximal femoral resection. To enable better function by maintaining leg length and offset, a custom-made antibiotic-eluting articulating temporary spacer, the Cement-a-TAN, was fabricated. Using a trochanteric entry cephalocondylar nail as a scaffold, bone cement was moulded in order to fashion an anatomical, patient-specific, proximal femoral spacer. Following resolution of the infection, the Cement-a-TAN was removed and a proximal femoral arthroplasty was successfully performed. Cement-a-TAN is an excellent temporary spacing technique in staged proximal femoral replacement for infected non-union of the
Abstract. Objectives. Osteoporosis of the pelvis and femur is diagnosed in a high proportion of lower-limb amputees which carries an increased fracture risk and subsequently serious implications on mobility, physical dependency and morbidity. Through the development of biofidelic musculoskeletal and finite element (FE) models, we aim to determine the effect of lower-limb amputation on long-term bone remodelling in the hip and to understand the potential underpinning mechanisms for bone degradation in the younger amputee population. Methods. Our models are patient specific and anatomically accurate. Geometries are derived from MRI-scans of one bilateral, above-knee, amputee and one body-matched control subject. Musculoskeletal modelling enables comparison of muscle and joint reaction-forces throughout gait. This provides the loading scenario implemented in FE. FE modelling demonstrates the effect of loading on the amputated limb via a prosthetic socket by comparing bone mechanical stimulation in amputee and control cases. Results. Musculoskeletal modelling shows that the bilateral amputee has 25% higher peak hip-reaction force than controls but a 54% lower peak knee-reaction force. Compensation for missing muscles and joints cause large-scale changes to the muscle loading patterns of the residual limb. FE analysis shows a 32% reduction in bone stimulation within the
Remodeling of the cancellous bone is more active than that of the cortical bone. It is known that the remodeling is governed by the intracancellous fluid pressure. Particularly, the lacunocanalicular pore (PLC) fluid pressure (FP) is essential for survival of the osteocyte and communication of remodeling signals between the PLC and intertrabecular pore (PIT). As a result, knowledge about the PLCFP generation of trabeculae is required to understand human cancellous bone biology. At this moment, the PLCFP measurement of human trabeculae is not reported. The purpose of this study was a direct measurement of PLCFP generation of human proximal femoral trabeculae in the direction of superior-to-fovea. Twenty one microscopic cylindrical trabecular specimens from trabeculae of five fresh human
The cortical strains on the femoral neck and