Hip fractures are associated with poor outcomes and high mortality rates of 30%. The current gold standard to measure bone fragility is a Dual-Energy X-ray Absorptiometry (DEXA) scan measuring bone mineral density. Yet DEXA under-diagnoses bone fragility by 50% (1). To combat the burden of bone fragility, this experimental study combined ultrasound (US) with a sophisticated computational algorithm, namely full wave inversion (FWI), to evaluate femoral bone structure. The aims were to assess the association of bone structure between the proximal femoral diaphysis and femoral neck; secondly to evaluate whether transverse ultrasound could assess bone structure of the proximal femoral diaphysis. Bone structure of 19 ex vivo human femora was assessed by micro-CT analysis (mean age 88.11 years, male:female 13:6)(Nikon HMXST 225). Using ImageJ/BoneJ, three 10.2mm subsections of proximal diaphysis and femoral neck underwent analysis: the total bone volume fraction, cortical parameters (bone volume fraction, porosity, thickness) and trabecular parameters (porosity, thickness, spacing and connectivity). A unique US prototype was developed to analyse fifteen femoral diaphyseal subsections using two P4-1 transducers with a novel tomography sequence (Verasonics, Matlab ver R2019a, FWI TRUST protocol). Comparative quantitative analysis of US and Micro-CT measurements was assessed (Graphpad Prism 8.3.1). Micro-CT analysis of the proximal femoral diaphysis demonstrated low correlation to the femoral neck (Pearson r −0.54 to 0.55). US was able to capture cortical structure, though a wide limit of agreement seen when compared to micro-CT analysis (Bland-Altman range 36–59% difference). This novel US technique was able to capture cortical bone structure. Improvements in methodology and technology are required to improve the analysis of trabecular bone and overall accuracy. Further evaluation of US and FWI is required to develop the technique and determine its role in clinical practice

The trend towards more minimal access has led to a series of instruments being developed to enable adequate access for Direct Anterior Approach (DAA) for hip arthroplasty. These include longer levers, hooks attached to the operating table and a series of special attachments to the operating table to position the leg and apply traction where necessary. The forces applied in this way may be transmitted locally, damaging muscle used as a fulcrum, or the knee and ankle joints when torque has to be applied to the femur through a boot. The arthroplasty surgeon's aim is to minimise the forces applied to both bone and soft tissue during surgery. We surmised that the forces needed for adequate access were related to the extent of the capsular and soft tissue releases, and that they could be measured and optimised. with the aim of minimising the forces applied to the tissues around the hip. Eight fresh frozen specimens from pelvis to mid tibia from four cadavers were approached using the DAA. A 6-axis force/torque sensor and 6-axis motion tracking sensor were attached to a threaded rod securely fastened to the tibial and femoral diaphysis. The torque needed to provide first extension, then external rotation, adequate for hip arthroplasty were measured as the capsular structures were divided sequentially. The Zona Orbicularis (ZO) and Ischiofemoral Ligament(IFL) contributed most of the resistance to both extension (4.0 and 3.1Nm) and external rotation torque (5.8 and 3.9Nm). The contributions of the conjoint tendon (1.5 and 2.4Nm) and piriformis (1.2 and 2.3Nm) were substantially smaller. By releasing the Zona Orbicularis and Ischiofemoral Ligament, the torque needed to deliver the femur for hip arthroplasty could be reduced to less than the torque needed to open a jar (2.9–5.5Nm)

Introduction. The Vancouver Classification System presents a systematic approach to classification of periprosthetic fractures of the proximal femur (PFPFs) that has been validated in previous studies. However, with the introduction of tapered fluted stems and cable plates since the introduction of the Vancouver System, the connection between fracture class and the preferred method of treatment is often unclear. The present study was undertaken to identify fracture patterns surrounding contemporary femoral stems and the relationship between the current method of treatment and the Vancouver Class of the periprosthetic fracture. Methods. Three experienced joint surgeons collected plain radiographs (AP and lateral) and CT/MR scans (n=40) from 72 cases of Vancouver A or B periprosthetic fractures performed over the period 2016–2018. We identified the mode of primary stem fixation and the Vancouver grade of the fracture (A, B1, B2 or B3). Two independent investigators examined all imaging studies and the intraoperative records and recorded: (i) and the location and distribution of the fracture surfaces, and (ii) the presence of incomplete cortical fractures that had initiated within the femoral cortex without completing propagation and (iii) the method of operative treatment. These data were analyzed to examine the incidence of fractures within more than one femoral zone and differences in the fracture patterns corresponding to each Vancouver class. Results. One fifth (21%) of fractures were Type A with the remainder consisting predominantly of Type B2 (39%), with approximately equal proportions of Type B1 (22%) and B3 (18%) fractures. In almost half of Type B2 fractures (a loose femoral stem and a fracture adjacent to the prosthesis), fractures were also present within the metaphysis (ie. Type A+B). In the presence of a cementless femoral stem, fractures often occurred adjacent to the uncoated surface of the stem distal to the proximal ingrowth surface. Type B2 and B3 femurs had similar fracture patterns and degrees of comminution, though their method of treatment differed significantly. Incomplete fractures were identified in every Vancouver class (entire sample: 22%), especially in association with loose stems in poor quality bone (Type B3; 38% of cases). Conclusions. Approximately two-thirds of periprosthetic femoral fractures involve a loose femoral component (ie Types B2 and B3), though bone quality impacts operative treatment. In cementless stems, Vancouver Type B fractures often occur in the unbonded diaphysis between the distal edge of the ingrowth surface and immediately below the stem tip. Incomplete fractures are present in a surprising proportion of cases, suggesting that careful examination of imaging studies is needed to prevent fracture propagation due to inadequate fixation. CT scans are a useful adjunct to supplement plain radiographs. For any tables or figures, please contact the authors directly

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When performing revision total hip arthroplasty using diaphyseal-engaging titanium tapered stems (TTS), the recommended 3 to 4 cm of stem-cortical diaphyseal contact may not be available. In challenging cases such as these with only 2 cm of contact, can sufficient axial stability be achieved and what is the benefit of a prophylactic cable? This study sought to determine, first, whether a prophylactic cable allows for sufficient axial stability when the contact length is 2 cm, and second, if differing TTS taper angles (2° vs 3.5°) impact these results.

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The objectives of this study were to investigate the patient characteristics and mortality of Vancouver type B periprosthetic femoral fractures (PFF) subgroups divided into two groups according to femoral component stability and to compare postoperative clinical outcomes according to treatment in Vancouver type B2 and B3 fractures.

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The risk factors for abnormal spinopelvic mobility (SPM), defined as an anterior rotation of the spinopelvic tilt (∆SPT) ≥ 20° in a flexed-seated position, have been described. The implication of pelvic incidence (PI) is unclear, and the concept of lumbar lordosis (LL) based on anatomical limits may be erroneous. The distribution of LL, including a unusual shape in patients with a high lordosis, a low pelvic incidence, and an anteverted pelvis seems more relevant.

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Total hip arthroplasty (THA) is considered the preferred treatment for displaced proximal femoral neck fractures. However, in many countries this option is economically unviable. To improve outcomes in financially disadvantaged populations, we studied the technique of concomitant valgus hip osteotomy and operative fixation (VOOF). This prospective serial study compares two treatment groups: VOOF versus operative fixation alone with cannulated compression screws (CCSs).

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It has been well documented in the arthroplasty literature that lumbar degenerative disc disease (DDD) contributes to abnormal spinopelvic motion. However, the relationship between the severity or pattern of hip osteoarthritis (OA) as measured on an anteroposterior (AP) pelvic view and spinopelvic biomechanics has not been well investigated. Therefore, the aim of the study is to examine the association between the severity and pattern of hip OA and spinopelvic motion.

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The aims of this study were to determine if an increasing serum cobalt (Co) and/or chromium (Cr) concentration is correlated with a decreasing Harris Hip Score (HHS) and Hip disability and Osteoarthritis Outcome Score (HOOS) in patients who received the Articular Surface Replacement (ASR) hip resurfacing arthroplasty (HRA), and to evaluate the ten-year revision rate and show if sex, inclination angle, and Co level influenced the revision rate.

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Assessment of bone mineral density (BMD) with dual-energy X-ray absorptiometry (DXA) is a well-established clinical technique, but it is not available in the acute trauma setting. Thus, it cannot provide a preoperative estimation of BMD to help guide the technique of fracture fixation. Alternative methods that have been suggested for assessing BMD include: 1) cortical measures, such as cortical ratios and combined cortical scores; and 2) aluminium grading systems from preoperative digital radiographs. However, limited research has been performed in this area to validate the different methods. The aim of this study was to investigate the evaluation of BMD from digital radiographs by comparing various methods against DXA scanning.

Introduction. Undersizing of an uncemented femoral stem is a post-operative description of a radiograph with unclear clinical importance. It may not always translate into a suboptimal clinical outcome. Aim. To describe a novel classification system of undersizing in a fully hydroxyapatite coated femoral implant, assess if it could be reliably reported between observers, and describe a simple way to assess the degree of undersizing on an AP radiograph. Methods. A retrospective review of 1000 consecutive total hip arthroplasties was conducted. Two investigators reviewed post-operative radiographs independently for stem undersizing. The data was tested for inter and intra-observer agreement using the Kappa method. Results. Undersizing was classified as:. Varus - Stem in contact proximally with medial calcar, and distally with lateral cortex. Valgus - Stem in contact proximally with lateral cortex, and distally with medial cortex. Uniform - Continuous margin around the stem of at least one-half tip width of the stem throughout. Champagne flute - Distal stem fills the narrow diaphysis with insufficient bony contact at the wide metaphysis. If varus or valgus undersizing was present we described the formation of two triangles of excess cancellous space around the implant, each having overlapping apices signifying undersizing by at least two sizes. 32% of the stems were undersized with Kappa demonstrating very good (89%) to good (86%) inter and intra observer agreement respectively. 50% of undersized stems were uniformly undersized, 36% were varus, 6% valgus, and 8% were in a champagne fluted shaped femur. A higher percentage of the lateralised (KLA) stems were undersized compared to other neck configurations (40%). 54% of these were varus undersized and this increased the offset up to 2cm. Conclusion. We describe a classification system for undersizing in hip arthroplasty. KLA stems have an increased tendency to be undersized in varus, thereby increasing the overall offset

Femoral revision after cemented total hip replacement (THR) might include technical difficulties, following essential cement removal, which might lead to further loss of bone and consequently inadequate fixation of the subsequent revision stem. . Femoral impaction allografting has been widely used in revision surgery for the acetabulum, and subsequently for the femur. In combination with a primary cemented stem, impaction grafting allows for femoral bone restoration through incorporation and remodelling of the impacted morsellized bone graft by the host skeleton. Cavitary bone defects affecting meta-physis and diaphysis leading to a wide femoral shaft, are ideal indications for this technique. Cancellous allograft bone chips of 1 mm to 2 mm size are used, and tapered into the canal with rods of increasing diameters. To impact the bone chips into the femoral canal a prosthesis dummy of the same dimensions of the definitive cemented stem is driven into the femur to ensure that the chips are very firmly impacted. Finally, a standard stem is cemented into the neo-medullary canal using bone cement. . To date several studies have shown favourable results with this technique, with some excellent long-term results reported in independent clinical centres worldwide. Cite this article: Bone Joint J 2013;95-B, Supple A:92–4

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Periprosthetic hip fractures (PPFs) after total hip arthroplasty are difficult to treat. Therefore, it is important to identify modifiable risk factors such as stem selection to reduce the occurrence of PPFs. This study aimed to clarify differences in fracture torque, surface strain, and fracture type analysis between three different types of cemented stems.

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The aim of this study was to determine the association between knee alignment and the vertical orientation of the femoral neck in relation to the floor. This could be clinically important because changes of femoral neck orientation might alter chondral joint contact zones and joint reaction forces, potentially inducing problems like pain in pre-existing chondral degeneration. Further, the femoral neck orientation influences the ischiofemoral space and a small ischiofemoral distance can lead to impingement. We hypothesized that a valgus knee alignment is associated with a more vertical orientation of the femoral neck in standing position, compared to a varus knee. We further hypothesized that realignment surgery around the knee alters the vertical orientation of the femoral neck.

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One-stage revision hip arthroplasty for periprosthetic joint infection (PJI) has several advantages; however, resection of the proximal femur might be necessary to achieve higher success rates. We investigated the risk factors for resection and re-revisions, and assessed complications and subsequent re-revisions.

Introduction. Porous surfaces developed over the past decades have been shown to promote tissue ingrowth. Hydroxyapatite (HA) coatings have been added to these porous coatings in an attempt to further augment bone ingrowth. The development of additive manufacturing techniques has allowed for precision in building these complex porous structures. The effect of supplemental HA coatings on these new surfaces is unclear. The purpose of this study is to evaluate the biological fixation of a novel 3D printed porous implant in a canine model. In addition, we evaluated the effect of different HA coatings on this 3D printed implant. Methods. A canine transcortical model was used to evaluate the performance of three different laser rapid manufacturing (LRM) Ti6Al4V cylindrical implants (5.2 mm diameter, 10mm length): LRM with precipitated hydroxyapatite (P-HA), LRM with plasma sprayed hydroxyapatite (PS-HA), and a hydroxyapatite-free control (No-HA). The implants were 50–60% porous with a mean pore size of 450 μm and have a random interconnected architecture with irregular pore sizes and shapes that are designed based on the structure of cancellous bone. A lateral approach to the femoral diaphysis was used to prepare 5 mm unicortical, perpendicular drill holes in 12 canines. One of each implant type was press-fit into each femur. The femora were harvested at both 4 and 12 weeks post implantation, radiographed and prepared for either mechanical push-out testing to assess the shear strength of the bone-implant interface (left femora, N=6) or for histological processing (right femora, N=6). An un-paired Student's t-test was used to compare statistical significance between the 4 and 12-week results, as well as differences due to implant type; p<0.05 was considered significant. Results. The post-mortem contact radiographs demonstrated substantial condensation of bone around the implants at both 4 and 12 weeks. Bone ingrowth in the canine femora was observed in all implants, with and without HA, at both time periods under backscattered SEM. The mean extent of bone ingrowth at 4 weeks for no-HA, P-HA, and PS-HA implants was 41.5% (95% CI 32.5 to 50.6), 51.0% (95% CI 45.2 to 56.8) and 53.2% (95% CI 41.6 to 64.7), respectively. The mean extent of bone ingrowth at 12 weeks for no-HA, P-HA, and PS-HA implants was 64.4% (95% CI 61.5 to 67.3), 59.9% (95% CI 51.9 to 67.8) and 64.9% (95% CI 58.2 to 71.6), respectively. There was no significant difference in the amount of bone ingrowth between the HA and non-HA coated implants at any of the time points. All the implants were successfully pushed out after 4 weeks of implantation. The mean shear strength from the push-out test at 4 weeks for the no-HA, P-HA, and PS-HA implants was calculated to be 21.6 MPa (95% CI 17.2 to 26.0), 20.7 MPa (95% CI 18.9 to 22.4), and 20.2 MPa (95% CI 16.3 to 24.2), respectively. At week 12, in two femora all three implant types had compressive failure before rupture of the bone-implant interface with a load of over 2000N. This suggests that the values of shear strength were higher than those calculated from the successful tests at 12 weeks. The mean shear strength for the remaining no-HA, P-HA and PS-HA implants at 12 weeks was calculated to be 39.9 MPa (95% CI 29.8 to 50.9), 33.7 MPa (95% CI 26.3 to 41.2), and 36.0 MPa (95% CI 29.53 to 42.4), respectively. For all implants, the mean shear strength at 12 weeks was statistically significantly greater than at 4 weeks (p<0.05). There was no significant difference in the shear strength between HA coated and non-HA coated implants at 4 or 12 weeks. Conclusion. At 4 and 12 weeks, all non-HA coated LRM Ti6Al4V implants consistently exhibited very high bone ingrowth and mechanical shear strength in the canine model. These results demonstrate that this novel additive manufactured porous implant promoted biological fixation in a canine model. There was no significant improvement in the extent of bone ingrowth with the addition of HA. This is in agreement with the literature indicating that topography is the dominant factor governing bone apposition to hydroxyapatite-coated implants. It is likely that in this model, the morphologic features and roughness of the surface of the LRM implants stimulated osteoblastic activity, so that the addition of HA had a non-significant effect

Occlusion of the femoral canal is an important step in cemented hip arthroplasty. The goal of occlusion is to allow cement pressurisation and prevent cement egress into the femoral diaphysis. There are numerous designs of cement plugs made out of different materials but there is no consensus or clinical guideline for the choice of cement restrictors. At our centre two types of plugs are used – autologous bone block from femoral canal and the gelatine C-plug (Depuy International). We conducted this study to evaluate the stability of these two plugs and their effect on quality of cementation. The purpose of our study was to assess retrospectively both the length of the “cement tail” i.e. the length of the cement column distal to the stem tip and the cement mantle quality in both groups. A retrospective comparative review was designed after approval from the local R & D department. Power analysis indicated that a minimum of 74 patients per group would be needed. A total of 203 consecutive patients were analysed, 89 received an autologous bone block and 114 had C-plugs. Apart from the plugs both the groups were treated similarly with regards to surgical approach, cementing and operative technique. Surgical technique was to achieve adequate pressurisation and a minimum length of cement tail. Immediate post-operative radiographs were used for analysis. The primary outcome measure was the length of the cement tail, i.e. the length of the cement column from the tip of the stem. The secondary outcome measure was the quality of cementing which was quantified using Barrack's grading. The data was tested for normality using the Shapiro-Wilk test. The means of cement tail lengths in between the two groups were compared using the Wilcoxon ranked sum test. The cementation grades were compared using ANOVA. The correlation between the length of cement tail and the quality of cementation was calculated using ordinal regression. Both the groups were similar in terms of age, sex and primary diagnosis. The mean cement tail length was 6.42 (SE 0.71 mms; range-0–31) in the bone block group and 17.11 (SE-1.34 mms; range 0–65.7 mms) in the C-plug group. This difference was statistically significant (p< 0.0001). The proportion of patients with good quality of cementation (grade A) was significantly higher in the bone block group (80.6%) as compared to the C-plug group (56%) (p < 0.0001). There was a negative correlation between the length of the cement tail and the Barrack grade (rho=0.398), indicating that a short cement tail is associated with better quality cementation. Quality of cementation is of paramount importance in cemented hip arthroplasty. Revision surgery can be more difficult and higher risk in the presence of a long cement tail. We have shown that better quality cementation and shorter cement tails can be achieved with the cheapest of all options for canal occlusion, an autologous bone block and recommend its use

This study reviewed the results of a cementless anatomical femoral component to give immediate post-operative stability, and with a narrow distal section in order not to contact the femoral cortex in the diaphysis, ensuring exclusively metaphyseal loading. A total of 471 patients (601 hips) who had a total hip replacement between March 1995 and February 2002 were included in the study. There were 297 men and 174 women. The mean age at the time of operation was 52.7 years (28 to 63). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients two weeks after operation and at the final follow-up examination. The mean follow-up was 8.8 years (5 to 12). The mean pre-operative Harris hip score was 41 points (16 to 54), which improved to a mean of 96 (68 to 100) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. Deep infection occurred in two hips (0.3%) which required revision. One hip (0.2%) required revision of the acetabular component for recurrent dislocation. Bone mineral densitometry revealed a minimal bone loss in the proximal femur. This cementless anatomical femoral component with metaphyseal loading but without distal fixation produced satisfactory fixation and encourages proximal femoral loading

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The processes linking long-term bisphosphonate treatment to atypical fracture remain elusive. To establish a means of exploring this link, we have examined how long-term bisphosphonate treatment with prior ovariectomy modifies femur fracture behaviour and tibia mass and shape in murine bones.

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The aim of this study was to determine whether fixation, as opposed to revision arthroplasty, can be safely used to treat reducible Vancouver B type fractures in association with a cemented collarless polished tapered femoral stem (the Exeter).