We undertook a randomised prospective follow-up study of changes in peri-prosthetic bone mineral density (BMD) after hip resurfacing and compared them with the results after total hip replacement. A total of 59 patients were allocated to receive a hip resurfacing (n = 29) or an uncemented distally fixed total hip replacement (n = 30). The BMD was prospectively determined in four separate
Osteoporosis can determine surgical strategy for total hip arthroplasty (THA), and perioperative fracture risk. The aims of this study were to use hip CT to measure femoral bone mineral density (BMD) using CT X-ray absorptiometry (CTXA), determine if systematic evaluation of preoperative femoral BMD with CTXA would improve identification of osteopenia and osteoporosis compared with available preoperative dual-energy X-ray absorptiometry (DXA) analysis, and determine if improved recognition of low BMD would affect the use of cemented stem fixation. Retrospective chart review of a single-surgeon database identified 78 patients with CTXA performed prior to robotic-assisted THA (raTHA) (Group 1). Group 1 was age- and sex-matched to 78 raTHAs that had a preoperative hip CT but did not have CTXA analysis (Group 2). Clinical demographics, femoral fixation method, CTXA, and DXA data were recorded. Demographic data were similar for both groups.Aims
Methods
This study was designed to develop a model for predicting bone mineral density (BMD) loss of the femur after total hip arthroplasty (THA) using artificial intelligence (AI), and to identify factors that influence the prediction. Additionally, we virtually examined the efficacy of administration of bisphosphonate for cases with severe BMD loss based on the predictive model. The study included 538 joints that underwent primary THA. The patients were divided into groups using unsupervised time series clustering for five-year BMD loss of Gruen zone 7 postoperatively, and a machine-learning model to predict the BMD loss was developed. Additionally, the predictor for BMD loss was extracted using SHapley Additive exPlanations (SHAP). The patient-specific efficacy of bisphosphonate, which is the most important categorical predictor for BMD loss, was examined by calculating the change in predictive probability when hypothetically switching between the inclusion and exclusion of bisphosphonate.Aims
Methods
Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs). A total of 20 patients with small and medium-size symptomatic stage II femoral head ON treated with 140 million BM-hMSCs through percutaneous forage in the EudraCT 2012-002010-39 clinical trial were retrospectively evaluated through preoperative and postoperative (three and 12 months) MRI. Then, 3D reconstruction of the original lesion and the observed postoperative residual damage after bone regeneration were analyzed and compared per group based on treatment efficacy.Aims
Methods
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. A total of 54 patients with distal radial fractures were included in the study. Each underwent posteroanterior (PA) and lateral radiographs of the injured wrist with an aluminium step wedge. Overall 27 patients underwent routine DXA scanning of the hip and lumbar spine, with 13 undergoing additional DXA scanning of the uninjured forearm. Analysis of radiographs was performed on ImageJ and Matlab with calculations of cortical measures, cortical indices, combined cortical scores, and aluminium equivalent grading.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
This study investigates head-neck taper corrosion with varying head size in a novel hip simulator instrumented to measure corrosion related electrical activity under torsional loads. In all, six 28 mm and six 36 mm titanium stem-cobalt chrome head pairs with polyethylene sockets were tested in a novel instrumented hip simulator. Samples were tested using simulated gait data with incremental increasing loads to determine corrosion onset load and electrochemical activity. Half of each head size group were then cycled with simulated gait and the other half with gait compression only. Damage was measured by area and maximum linear wear depth.Aims
Methods
Surgical treatment of young femoral neck fractures often requires an open approach to achieve an anatomical reduction. The application of a calcar plate has recently been described to aid in femoral neck fracture reduction and to augment fixation. However, application of a plate may potentially compromise the regional vascularity of the femoral head and neck. The purpose of this study was to investigate the effect of calcar femoral neck plating on the vascularity of the femoral head and neck. A Hueter approach and capsulotomy were performed bilaterally in six cadaveric hips. In the experimental group, a one-third tubular plate was secured to the inferomedial femoral neck at 6:00 on the clockface. The contralateral hip served as a control with surgical approach and capsulotomy without fixation. Pre- and post-contrast MRI was then performed to quantify signal intensity in the femoral head and neck. Qualitative assessment of the terminal arterial branches to the femoral head, specifically the inferior retinacular artery (IRA), was also performed.Aims
Methods
Type 2 diabetes mellitus (T2DM) impairs bone strength and is a significant risk factor for hip fracture, yet currently there is no reliable tool to assess this risk. Most risk stratification methods rely on bone mineral density, which is not impaired by diabetes, rendering current tests ineffective. CT-based finite element analysis (CTFEA) calculates the mechanical response of bone to load and uses the yield strain, which is reduced in T2DM patients, to measure bone strength. The purpose of this feasibility study was to examine whether CTFEA could be used to assess the hip fracture risk for T2DM patients. A retrospective cohort study was undertaken using autonomous CTFEA performed on existing abdominal or pelvic CT data comparing two groups of T2DM patients: a study group of 27 patients who had sustained a hip fracture within the year following the CT scan and a control group of 24 patients who did not have a hip fracture within one year. The main outcome of the CTFEA is a novel measure of hip bone strength termed the Hip Strength Score (HSS).Aims
Methods
Dual mobility implants in total hip arthroplasty are designed to increase the functional head size, thus decreasing the potential for dislocation. Modular dual mobility (MDM) implants incorporate a metal liner (e.g. cobalt-chromium alloy) in a metal shell (e.g. titanium alloy), raising concern for mechanically assisted crevice corrosion at the modular liner-shell connection. We sought to examine fretting and corrosion on MDM liners, to analyze the corrosion products, and to examine histologically the periprosthetic tissues. A total of 60 retrieved liners were subjectively scored for fretting and corrosion. The corrosion products from the three most severely corroded implants were removed from the implant surface, imaged using scanning electron microscopy, and analyzed using Fourier-transform infrared spectroscopy.Aims
Methods
Osteolysis, secondary to local and systemic physiological effects, is a major challenge in total hip arthroplasty (THA). While osteolytic defects are commonly observed in long-term follow-up, how such lesions alter the distribution of stress is unclear. The aim of this study was to quantitatively describe the biomechanical implication of such lesions by performing subject-specific finite-element (FE) analysis on patients with osteolysis after THA. A total of 22 hemipelvis FE models were constructed in order to assess the transfer of load in 11 patients with osteolysis around the acetabular component of a THA during slow walking and a fall onto the side. There were nine men and two women. Their mean age was 69 years (55 to 81) at final follow-up. Changes in peak stress values and loads to fracture in the presence of the osteolytic defects were measured.Aims
Patients and Methods
Early evidence has emerged suggesting that ceramic-on-ceramic
articulations induce a different tissue reaction to ceramic-on-polyethylene
and metal-on-metal bearings. Therefore, the aim of this study was
to investigate the tissue reaction and cellular response to ceramic
total hip arthroplasty (THA) materials We investigated tissue collected at revision surgery from nine
ceramic-on-ceramic articulations. we compared our findings with
tissue obtained from five metal-on-metal THA revisions, four ceramic-on-polyethylene
THAs, and four primary osteoarthritis synovial membranes. The latter
were analyzed to assess the amount of tissue fibrosis that might
have been present at the time of implantation to enable evaluation,
in relation to implantation time, of any subsequent response in
the tissues.Aims
Patients and Methods
The primary purpose of this study of metal-on-metal
(MoM) hip resurfacing was to compare the effect of using a cementless
or cemented femoral component on the subsequent bone mineral density
(BMD) of the femoral neck. This was a single-centre, prospective, double-blinded control
trial which randomised 120 patients (105 men and 15 women) with
a mean age of 49.4 years (21 to 68) to receive either a cemented
or cementless femoral component. Follow-up was to two years. Outcome
measures included total and six-point region-of-interest BMD of
the femoral neck, radiological measurements of acetabular inclination,
neck-shaft and stem-shaft angles, and functional outcome scores
including the Harris hip score, the Western Ontario and McMaster
Universities Osteoarthritis Index and the University of California
at Los Angeles activity scale. In total, 17 patients were lost to follow-up leaving 103 patients
at two years. There were no revisions in the cementless group and
three revisions (5%) in the cemented group (two because of hip pain
and one for pseudotumour). The total BMD was significantly higher in the cementless group
at six months (p <
0.001) and one year (p = 0.01) than in the
cemented group, although there was a loss of statistical significance
in the difference at two years (p = 0.155). All patient outcomes improved significantly: there were no significant
differences between the two groups. The results show better preservation of femoral neck BMD with
a cementless femoral component after two years of follow-up. Further
investigation is needed to establish whether this translates into
improved survivorship. Cite this article:
The aim of this study was to examine the real time A total of 50 patients (83 hips) underwent 4D dynamic CT scanning
of the hip, producing real time osseous models of the pelvis and
femur being moved through flexion, adduction, and internal rotation.
The location and size of the cam deformity and its relationship
to the angle of flexion of the hip and pelvic tilt, and the position
of impingement were recorded.Aims
Patients and Methods
We aimed to quantify the relative contributions of the medial
femoral circumflex artery (MFCA) and lateral femoral circumflex
artery (LFCA) to the arterial supply of the head and neck of the
femur. We acquired ten cadaveric pelvises. In each of these, one hip
was randomly assigned as experimental and the other as a matched
control. The MFCA and LFCA were cannulated bilaterally. The hips
were designated LFCA-experimental or MFCA-experimental and underwent
quantitative MRI using a 2 mm slice thickness before and after injection
of MRI-contrast diluted 3:1 with saline (15 ml Gd-DTPA) into either
the LFCA or MFCA. The contralateral control hips had 15 ml of contrast
solution injected into the root of each artery. Next, the MFCA and
LFCA were injected with a mixture of polyurethane and barium sulfate
(33%) and their extra-and intra-arterial course identified by CT
imaging and dissection.Aims
Materials and Methods
To study the vascularity and bone metabolism of the femoral head/neck
following hip resurfacing arthroplasty, and to use these results
to compare the posterior and the trochanteric-flip approaches. In our previous work, we reported changes to intra-operative
blood flow during hip resurfacing arthroplasty comparing two surgical
approaches. In this study, we report the vascularity and the metabolic
bone function in the proximal femur in these same patients at one
year after the surgery. Vascularity and bone function was assessed
using scintigraphic techniques. Of the 13 patients who agreed to
take part, eight had their arthroplasty through a posterior approach
and five through a trochanteric-flip approach.Objectives
Methods
The accuracy and precision of two new methods of model-based
radiostereometric analysis (RSA) were hypothesised to be superior
to a plain radiograph method in the assessment of polyethylene (PE)
wear. A phantom device was constructed to simulate three-dimensional
(3D) PE wear. Images were obtained consecutively for each simulated
wear position for each modality. Three commercially available packages
were evaluated: model-based RSA using laser-scanned cup models (MB-RSA),
model-based RSA using computer-generated elementary geometrical
shape models (EGS-RSA), and PolyWare. Precision (95% repeatability
limits) and accuracy (Root Mean Square Errors) for two-dimensional
(2D) and 3D wear measurements were assessed.Objectives
Methods
Bisphosphonates reduce peri-prosthetic bone loss in the short term after total hip replacement but the mid- and longer term effects are not known. The aims of this randomised trial were to examine the effect of a single dose of 90 mg of pamidronate on the clinical and radiological outcome and peri-prosthetic bone mineral density in 50 patients (56 hips) over a five-year period, following total hip replacement. At five years, 37 patients (42 hips) returned for assessment. The Harris hip scores were similar in the pamidronate and placebo groups throughout the study. Also at five years, four patients, two from each group had osteolytic lesions on plain radiography. These were located around the acetabular component in three patients and in the femoral calcar in one. The femoral and acetabular peri-prosthetic bone mineral density in the pamidronate group and the control group was similar at five years. Pamidronate given as a single post-operative dose does not appear to influence the clinical outcome or prevent the development of osteolytic lesions at five years after total hip replacement.
The major advantage of hip resurfacing is the decreased amount of bone resection compared with a standard total hip replacement. Fracture of the femoral neck is the most common early complication and poor bone quality is a major risk factor. We undertook a prospective consecutive case control study examining the effect of bone mineral density changes in patients undergoing hip resurfacing surgery. A total of 423 patients were recruited with a mean age of 54 years (24 to 87). Recruitment for this study was dependent on pre-operative bilateral femoral bone mineral density results not being osteoporotic. The operated and non-operated hips were assessed. Bone mineral density studies were repeated over a two-year period. The results showed no significant deterioration in the bone mineral density in the superolateral region in the femoral neck, during that period. These findings were in the presence of a markedly increased level of physical activity, as measured by the short-form 36 health survey physical function score.
Our aim in this prospective study was to compare the bone mineral density (BMD) around cementless acetabular and femoral components which were identical in geometry and had the same alumina modular femoral head, but differed in regard to the material of the acetabular liners (alumina ceramic or polyethylene) in 50 patients (100 hips) who had undergone bilateral simultaneous primary total hip replacement. Dual energy X-ray absorptiometry scans of the pelvis and proximal femur were obtained at one week, at one year, and annually thereafter during the five-year period of the study. At the final follow-up, the mean BMD had increased significantly in each group in acetabular zone I of DeLee and Charnley (20% (15% to 26%), p = 0.003), but had decreased in acetabular zone II (24% (18% to 36%) in the alumina group and 25% (17% to 31%) in the polyethylene group, p = 0.001). There was an increase in the mean BMD in zone III of 2% (0.8% to 3.2%) in the alumina group and 1% (0.6% to 2.2%) in the polyethylene group (p = 0.315). There was a decrease in the mean BMD in the calcar region (femoral zone 7) of 15% (8% to 24%) in the alumina group and 14% (6% to 23%) in the polyethylene group (p <
0.001). The mean bone loss in femoral zone 1 of Gruen et al was 2% (1.1% to 3.1%) in the alumina group and 3% (1.3% to 4.3%) in the polyethylene group (p = 0.03), and in femoral zone 6, the mean bone loss was 15% (9% to 27%) in the alumina group and 14% (11% to 29%) in the polyethylene group compared with baseline values. There was an increase in the mean BMD on the final scans in femoral zones 2 (p = 0.04), 3 (p = 0.04), 4 (p = 0.12) and 5 (p = 0.049) in both groups. There was thus no significant difference in the bone remodelling of the acetabulum and femur five years after total hip replacement in those two groups where the only difference was in the acetabular liner.
