The purpose of this randomized controlled trial was to evaluate serum metal ion levels in patients undergoing THA with either a standard or modular dual-mobility bearing. Patients undergoing primary THA for osteoarthritis were randomized to receive either a modular dual-mobility or a standard polyethylene bearing. All patients received the same titanium acetabular and femoral component and a ceramic femoral head. Only patients without a prior history of
This study aimed to develop and validate a fully automated system that quantifies proximal femoral bone mineral density (BMD) from CT images. The study analyzed 978 pairs of hip CT and dual-energy X-ray absorptiometry (DXA) measurements of the proximal femur (DXA-BMD) collected from three institutions. From the CT images, the femur and a calibration phantom were automatically segmented using previously trained deep-learning models. The Hounsfield units of each voxel were converted into density (mg/cm3). Then, a deep-learning model trained by manual landmark selection of 315 cases was developed to select the landmarks at the proximal femur to rotate the CT volume to the neutral position. Finally, the CT volume of the femur was projected onto the coronal plane, and the areal BMD of the proximal femur (CT-aBMD) was quantified. CT-aBMD correlated to DXA-BMD, and a receiver operating characteristic (ROC) analysis quantified the accuracy in diagnosing osteoporosis.Aims
Methods
The objective of this study was to compare the two-year migration and clinical outcomes of a new cementless hydroxyapatite (HA)-coated titanium acetabular shell with its previous version, which shared the same geometrical design but a different manufacturing process for applying the titanium surface. Overall, 87 patients undergoing total hip arthroplasty (THA) were randomized to either a Trident II HA or Trident HA shell, each cementless with clusterholes and HA-coating. All components were used in combination with a cemented Exeter V40 femoral stem. Implant migration was measured using radiostereometric analysis (RSA), with radiographs taken within two days of surgery (baseline), and at three, 12, and 24 months postoperatively. Proximal acetabular component migration was the primary outcome measure. Clinical scores and patient-reported outcome measures (PROMs) were collected at each follow-up.Aims
Methods
Metal-on-metal bearings are being increasingly used in young patients. The potential adverse effects of systemic metal ion elevation are the subject of ongoing investigation. The purpose of this study was to investigate whether cobalt and chromium ions cross the placenta of pregnant women with a metal-on-metal hip resurfacing and reach the developing fetus. Whole blood levels were estimated using high-resolution inductively-coupled plasma mass spectrometry. Our findings showed that cobalt and chromium are able to cross the placenta in the study patients with metal-on-metal hip resurfacings and in control subjects without any
Our objective was describing an algorithm to identify and prevent vascular injury in patients with intrapelvic components. Patients were defined as at risk to vascular injuries when components or cement migrated 5 mm or more beyond the ilioischial line in any of the pelvic incidences (anteroposterior and Judet view). In those patients, a serial investigation was initiated by a CT angiography, followed by a vascular surgeon evaluation. The investigation proceeded if necessary. The main goal was to assure a safe tissue plane between the hardware and the vessels.Aims
Methods
Introduction. As new innovations are developed to improve the longevity of joint replacement components, preclinical testing is necessary in the early stages of research into areas such as osseointegration, metal-cartilage wear and periprosthetic joint infection (PJI). Large-animal studies that test load-bearing components are expensive, however, requiring that animals be housed in special facilities that are not available at all institutions. Comparably, small animal models, such as the rat, offer several advantages including lower cost. Load-bearing implants remain difficult to manufacture via traditional methods in the sizes required for small-animal testing. Recent advances in additive manufacturing (3D metal-printing) have allowed for the creation of miniature joint replacement components in a variety of medical-grade metal alloys. The objective of this work is to create and optimize an image-based 3D-printed rat hip implant system that will allow in vivo testing of functional implant properties in a rat model. Methods. A database of n=25 previously-acquired, 154μm micro-CT volumes (eXplore Locus Ultra, GE Medical) of male Sprague-Dawley rats (390–610g) were analyzed to obtain spatial and angular relationships between several anatomical features of the proximal rat femora. Mean measurements were used to guide the creation of a femoral implant template in computer-aided design software (Solidworks, Dassault Systemes). Several different variations were created, including collarless and collared designs, in a range of sizes to accommodate rats of various weights. Initial prototypes were 3D-printed 316L stainless steel with subsequent iterations printed in Ti6Al4V titanium and F75 cobalt-chrome. Implants were post-processed via sandblasting, hand-polishing, ultrasonic bath, and sterilization in an autoclave. Innate surface texturing was left on manufactured stems to promote osseointegration. Surgical implantation was performed in three live Sprague-Dawley rats (900g, 500g, 750g) with preservation of muscle attachments to the greater trochanter. Micro-CT imaging and X-ray fluoroscopy were performed post-operatively on each animal at 1 day, and 1, 3, 9 and 12 weeks to evaluate gait and component positioning. Results. Implantation of components was successful and each animal was observed to ambulate on its affected limb immediately following recovery from surgery. The 900g rat, given a collarless 316L stainless steel component, was kept for 11 months post-implantation before succumbing to old age. Micro-CT and fluoroscopic findings revealed no evidence of implant subsidence. The 500g animal, given a collarless 316L stainless steel implant, showed evidence of implant subsidence at 3 weeks, with full subsidence and hip dislocation at 12 weeks. The 750g rat, given a collared F75 cobalt-chrome implant, was observed ambulating on its affected limb, but experienced implant rotation and failure at 9 weeks. Conclusions. We report the first hip hemi-arthroplasty in a rat using a 3D-printed
An atypical femoral fracture (AFF), with a transverse
fracture radiologically through the lateral cortex is a rare but serious
condition. In order to improve our ability to identify patients
with this condition, we retrospectively surveyed all subtrochanteric,
peri-implant and diaphyseal femoral fractures in patients aged ≥ 65
years who underwent surgical treatment at our hospital between 2004
and 2011. We describe the incidence of atypical fractures and their characteristics,
with observational data including a review of the hospital and general
practitioner records. Clinical outcomes were evaluated using the
Harris hip score (HHS) and the timed up-and-go (TUG) test. Atypical fractures only occurred in women with an incidence of
9.8 per 100 000 person-years. The incidence in those who were treated
with bisphosphonates was 79.0 per 100 000 person-years; eight of
17 fractures occurred around
Acetabular edge-loading was a cause of increased wear rates in metal-on-metal hip arthroplasties, ultimately contributing to their failure. Although such wear patterns have been regularly reported in retrieval analyses, this study aimed to determine their in vivo location and investigate their relationship with acetabular component positioning. 3D CT imaging was combined with a recently validated method of mapping bearing surface wear in retrieved hip implants. The asymmetrical stabilizing fins of Birmingham hip replacements (BHRs) allowed the co-registration of their acetabular wear maps and their computational models, segmented from CT scans. The in vivo location of edge-wear was measured within a standardized coordinate system, defined using the anterior pelvic plane.Aims
Methods
The aims of this study were to develop an in vivo model of periprosthetic joint infection (PJI) in cemented hip hemiarthroplasty, and to monitor infection and biofilm formation in real-time. Sprague-Dawley rats underwent cemented hip hemiarthroplasty via the posterior approach with pre- and postoperative gait assessments. Infection with Aims
Methods
Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system’s response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Patient peri-implant fibrotic tissue was analyzed for NETs biomarkers. To enhance osseointegration in loose implant conditions, an innate immune system pathway (NETs) was either inhibited (Aims
Methods
Uncemented metal acetabular components show good osseointegration, but material stiffness causes stress shielding and retroacetabular bone loss. Cemented monoblock polyethylene components load more physiologically; however, the cement bone interface can suffer fibrous encapsulation and loosening. It was hypothesized that an uncemented titanium-sintered monoblock polyethylene component may offer the optimum combination of osseointegration and anatomical loading. A total of 38 patients were prospectively enrolled and received an uncemented monoblock polyethylene acetabular (pressfit) component. This single cohort was then retrospectively compared with previously reported randomized cohorts of cemented monoblock (cemented) and trabecular metal (trabecular) acetabular implants. The primary outcome measure was periprosthetic bone density using dual-energy x-ray absorptiometry over two years. Secondary outcomes included radiological and clinical analysis.Aims
Methods
We have previously demonstrated raised cobalt and chromium levels in patients with larger diameter femoral heads, following metal-on-polyethylene uncemented total hip arthroplasty. Further data have been collected, to see whether these associations have altered with time and to determine the long-term implications for these patients and our practice. Patients from our previous study who underwent Trident-Accolade primary total hip arthroplasties using a metal-on-polyethylene bearing in 2009 were reviewed. Patients were invited to have their cobalt and chromium levels retested, and were provided an Oxford Hip Score. Serum ion levels were then compared between groups (28 mm, 36 mm, and 40 mm heads) and over time.Aims
Methods
This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment.Aims
Methods
Using a simple classification method, we aimed to estimate the collapse rate due to osteonecrosis of the femoral head (ONFH) in order to develop treatment guidelines for joint-preserving surgeries. We retrospectively analyzed 505 hips from 310 patients (141 men, 169 women; mean age 45.5 years Objectives
Methods
The purpose of this study was to evaluate the biological fixation of a 3D printed porous implant, with and without different hydroxyapatite (HA) coatings, in a canine model. A canine transcortical model was used to evaluate the characteristics of bone ingrowth of Ti6Al4V cylindrical implants fabricated using laser rapid manufacturing (LRM). At four and 12 weeks post-implantation, we performed histological analysis and mechanical push-out testing on three groups of implants: a HA-free control (LRM), LRM with precipitated HA (LRM-PA), and LRM with plasma-sprayed HA (LRM-PSHA).Aims
Materials and Methods
Modular dual mobility (DM) prostheses in which a cobalt-chromium liner is inserted into a titanium acetabular shell ( This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m2 and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. A total of 43 patients (30 male, 13 female; mean age 52.6 years (Aims
Patients and Methods
Few reconstructive techniques are available for patients requiring
complex acetabular revisions such as those involving Paprosky type
2C, 3A and 3B deficiencies and pelvic discontinuity. Our aim was
to describe the development of the patient specific Triflange acetabular
component for use in these patients, the surgical technique and
mid-term results. We include a description of the pre-operative
CT scanning, the construction of a model, operative planning, and
surgical technique. All implants were coated with porous plasma
spray and hydroxyapatite if desired. A multicentre, retrospective review of 95 complex acetabular
reconstructions in 94 patients was performed. A total of 61 (64.2%)
were female. The mean age of the patients was 66 (38 to 85). The
mean body mass index was 29 kg/m2 (18 to 51). Outcome
was reported using the Harris Hip Score (HHS), complications, failures
and survival.Aims
Patients and Methods
Until now, there has been no consensus as to whether stemmed
acetabular components are appropriate for use in patients undergoing
revision total hip arthroplasty (THA) who have major acetabular
defects or pelvic discontinuity. We wished to address this deficiency
in the literature. We carried out a retrospective study of 35 patients (six men
and 29 women) with a mean age of 68 years (37 to 87), with major
acetabular defects who underwent revision THA between 2000 and 2012.Aim
Patients and Methods
The aims of this piece of work were to: 1) record the background
concentrations of blood chromium (Cr) and cobalt (Co) concentrations
in a large group of subjects; 2) to compare blood/serum Cr and Co
concentrations with retrieved metal-on-metal (MoM) hip resurfacings;
3) to examine the distribution of Co and Cr in the serum and whole
blood of patients with MoM hip arthroplasties; and 4) to further
understand the partitioning of metal ions between the serum and
whole blood fractions. A total of 3042 blood samples donated to the local transfusion
centre were analysed to record Co and Cr concentrations. Also, 91
hip resurfacing devices from patients who had given pre-revision
blood/serum samples for metal ion analysis underwent volumetric
wear assessment using a coordinate measuring machine. Linear regression analysis
was carried out and receiver operating characteristic curves were
constructed to assess the reliability of metal ions to identify
abnormally wearing implants. The relationship between serum and
whole blood concentrations of Cr and Co in 1048 patients was analysed
using Bland-Altman charts. This relationship was further investigated
in an Objectives
Methods
This study reports the clinical outcome of reconstruction
of deficient abductor muscles following revision total hip arthroplasty
(THA), using a fresh–frozen allograft of the extensor mechanism
of the knee. A retrospective analysis was conducted of 11 consecutive
patients with a severe limp because of abductor deficiency which
was confirmed on MRI scans. The mean age of the patients (three
men and eight women) was 66.7 years (52 to 84), with a mean follow-up
of 33 months (24 to 41). Following surgery, two patients had no limp, seven had a mild
limp, and two had a persistent severe limp (p = 0.004). The mean
power of the abductors improved on the Medical Research Council
scale from 2.15 to 3.8 (p <
0.001). Pre-operatively, all patients
required a stick or walking frame; post-operatively, four patients
were able to walk without an aid. Overall, nine patients had severe
or moderate pain pre-operatively; ten patients had no or mild pain
post-operatively. At final review, the Harris hip score was good in five patients,
fair in two and poor in four. We conclude that using an extensor mechanism allograft is relatively
effective in the treatment of chronic abductor deficiency of the
hip after THA when techniques such as local tissue transfer are
not possible. Longer-term follow-up is necessary before the technique can be
broadly applied. Cite this article:
