Recent guidance recommends the use of a well-proven
cemented femoral stem for hemiarthroplasty in the management of
fractures of the femoral neck, and the Exeter Trauma Stem (ETS)
has been suggested as an example of such an implant. The design
of this stem was based on the well-proven Exeter Total Hip Replacement
stem (ETHRS). This study assessed the
The mechanical performance of the cement-in-cement interface in revision surgery has not been fully investigated. The quantitative effect posed by interstitial fluids and roughening of the primary mantle remains unclear. We have analysed the strength of the bilaminar cement-bone interface after exposure of the surface of the primary mantle to roughening and fluid interference. The end surfaces of cylindrical blocks of cement were machined smooth (Ra = 200 nm) or rough (Ra = 5 μm) and exposed to either different volumes of water and carboxymethylcellulose (a bone-marrow equivalent) or left dry. Secondary blocks were cast against the modelled surface. Monoblocks of cement were used as a control group. The porosity of the samples was investigated using micro-CT. Samples were exposed to a single shearing force to failure. The mean failure load of the monoblock control was 5.63 kN (95% confidence interval (CI) 5.17 to 6.08) with an estimated shear strength of 36 MPa. When small volumes of any fluid or large volumes were used, the respective values fell between 4.66 kN and 4.84 kN with no significant difference irrespective of roughening (p >
0.05). Large volumes of carboxymethylcellulose significantly weakened the interface. Roughening in this group significantly increased the strength with failure loads of 2.80 kN (95% CI 2.37 to 3.21) compared with 0.86 kN (95% CI 0.43 to 1.27) in the smooth variant. Roughening of the primary mantle may not therefore be as crucial as has been previously thought in clinically relevant circumstances.
We examined the behaviour of alumina ceramic heads in 156 cemented total hip arthroplasties, at a minimum follow-up of eight years. They were divided into three groups according to the size of the femoral head; 22, 26, and 28 mm. We measured polyethylene wear radiologically using a computer-aided technique. The linear wear rate of polyethylene sockets for the 28 mm heads was high (0.156 mm/year), whereas those for the 22 and 26 mm heads were relatively low (0.090 and 0.098 mm/year, respectively). Moreover, the surface roughness data of retrieved femoral heads clearly showed maintenance of an excellent
The aim of this study was to compare the pattern of initial fixation and changes in periprosthetic bone mineral density (BMD) between patients who underwent total hip arthroplasty (THA) using a traditional fully hydroxyapatite (HA)-coated stem (T-HA group) and those with a newly introduced fully HA-coated stem (N-HA group). The study included 36 patients with T-HA stems and 30 with N-HA stems. Dual-energy X-ray absorptiometry was used to measure the change in periprosthetic BMD, one and two years postoperatively. The 3D contact between the stem and femoral cortical bone was evaluated using a density-mapping system, and clinical assessment, including patient-reported outcome measurements, was recorded.Aims
Methods
Highly polished stems with force-closed design have shown satisfactory clinical results despite being related to relatively high early migration. It has been suggested that the minimal thickness of cement mantles surrounding the femoral stem should be 2 mm to 4 mm to avoid aseptic loosening. The line-to-line cementing technique of the femoral stem, designed to achieve stem press-fit, challenges this opinion. We compared the migration of a highly polished stem with force-closed design by standard and line-to-line cementing to investigate whether differences in early migration of the stems occur in a clinical study. In this single-blind, randomized controlled, clinical radiostereometric analysis (RSA) study, the migration pattern of the cemented Corail hip stem was compared between line-to-line and standard cementing in 48 arthroplasties. The primary outcome measure was femoral stem migration in terms of rotation and translation around and along with the X-, Y-, and Z- axes measured using model-based RSA at three, 12, and 24 months. A linear mixed-effects model was used for statistical analysis.Aims
Methods
The aim of this study was to estimate the 90-day risk of revision for periprosthetic femoral fracture associated with design features of cementless femoral stems, and to investigate the effect of a collar on this risk using a biomechanical A total of 337 647 primary total hip arthroplasties (THAs) from the United Kingdom National Joint Registry (NJR) were included in a multivariable survival and regression analysis to identify the adjusted hazard of revision for periprosthetic fracture following primary THA using a cementless stem. The effect of a collar in cementless THA on this risk was evaluated in an Aims
Materials and 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
The aim of this study was to compare the design of the generic
OptiStem XTR femoral stem with the established Exeter femoral stem. We obtained five boxed, as manufactured, implants of both designs
at random (ten in total). Two examiners were blinded to the implant
design and independently measured the mass, volume, trunnion surface
topography, trunnion roughness, trunnion cone angle, Caput-Collum-Diaphyseal
(CCD) angle, femoral offset, stem length, neck length, and the width
and roughness of the polished stem shaft using peer-reviewed methods.
We then compared the stems using these parameters.Aims
Materials 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
Our aim in this study was to describe a continuing review of
11 total hip arthroplasties using 22.225 mm Alumina ceramic femoral
heads on a Charnley flanged femoral component, articulating against
a silane crosslinked polyethylene. Nine patients (11 THAs) were reviewed at a mean of 27.5 years
(26 to 28) post-operatively. Outcome was assessed using the d’Aubigne
and Postel, and Charnley scores and penetration was recorded on
radiographs. In addition, the oxidation of a 29-year-old shelf-aged
acetabular component was analysed.Aims
Patients and Methods
Tantalum (Ta) trabecular metal components are increasingly used
to reconstruct major bone defects in revision arthroplasty surgery.
It is known that some metals such as silver have antibacterial properties.
Recent reports have raised the question regarding whether Ta components
are protective against infection in revision surgery. This laboratory
study aimed to establish whether Ta has intrinsic antibacterial
properties against planktonic bacteria, or the ability to inhibit
biofilm formation. Equal-sized pieces of Ta and titanium (Ti) acetabular components
were sterilised and incubated with a low dose inoculum of either Aims
Materials and Methods
We describe our technique and rationale using
hybrid fixation for primary total hip arthroplasty (THA) at the Hospital
for Special Surgery. Modern uncemented acetabular components have
few screw holes, or no holes, polished inner surfaces, improved
locking mechanisms, and maximised thickness and shell-liner conformity. Uncemented
sockets can be combined with highly cross-linked polyethylene liners,
which have demonstrated very low wear and osteolysis rates after
ten to 15 years of implantation. The results of cement fixation
with a smooth or polished surface finished stem have been excellent,
virtually eliminating complications seen with cementless fixation
like peri-operative femoral fractures and thigh pain. Although mid-term
results of modern cementless stems are encouraging, the long-term
data do not show reduced revision rates for cementless stems compared
with cemented smooth stems. In this paper we review the conduct
of a hybrid THA, with emphasis on pre-operative planning, surgical
technique, hypotensive epidural anaesthesia, and intra-operative
physiology. Cite this article:
This was a safety study where the hypothesis was that the newer-design CPCS femoral stem would demonstrate similar early clinical results and micromovement to the well-established Exeter stem. Both are collarless, tapered, polished cemented stems, the only difference being a slight lateral to medial taper with the CPCS stem. A total of 34 patients were enrolled in a single-blinded randomised controlled trial in which 17 patients received a dedicated radiostereometric CPCS stem and 17 a radiostereometric Exeter stem. No difference was found in any of the outcome measures pre-operatively or post-operatively between groups. At two years, the mean subsidence for the CPCS stem was nearly half that seen for the Exeter stem (0.77 mm (−0.943 to 1.77) and 1.25 mm (0.719 to 1.625), respectively; p = 0.032). In contrast, the mean internal rotation of the CPCS stem was approximately twice that of the Exeter (1.61° (−1.07° to 4.33°) and 0.59° (0.97° to 1.64°), respectively; p = 0.048). Other migration patterns were not significantly different between the stems. The subtle differences in designs may explain the different patterns of migration. Comparable migration with the Exeter stem suggests that the CPCS design will perform well in the long term.
We present the medium-term results of hybrid total hip arthroplasties using pre-coated stems with a second-generation cementing technique. The 128 hips in 111 patients (18 men and 93 women) were followed up at a mean of 11 years after surgery. The mean age at the time of surgery was 61 years. Both components of one hip were removed at ten months after surgery for infection. None of the other 127 femoral components showed possible, probable, or definite loosening at the most recent follow-up. Five acetabular components were revised for aseptic loosening, recurrent dislocation, or displacement of the polyethylene liner from the metal shell. The mean Harris hip score at follow-up was 84 points. A pre-coated femoral component with a second-generation cementing technique provides good clinical function and survival in the medium term.
Most published randomised controlled trials which
compare the rates of wear of conventional and cross-linked (XL) polyethylene
(PE) in total hip arthroplasty (THA) have described their use with
a cementless acetabular component. We conducted a prospective randomised study to assess the rates
of penetration of two distinct types of PE in otherwise identical
cemented all-PE acetabular components. A total of 100 consecutive patients for THA were randomised to
receive an acetabular component which had been either highly XL
then remelted or moderately XL then annealed. After a minimum of eight years follow-up, 38 hips in the XL group
and 30 hips in the annealed group had complete data (mean follow-up
of 9.1 years (7.6 to 10.7) and 8.7 years (7.2 to 10.2), respectively).
In the XL group, the steady state rate of penetration from one year
onwards was -0.0002 mm/year ( These results show that the yearly linear rate of femoral head
penetration can be significantly reduced by using a highly XLPE
cemented acetabular component. Cite this article:
The original forged Müller straight stem (CoNiCr) has shown excellent ten- to 15-year results. We undertook a long-term survival analysis with special emphasis on radiological changes within a 20-year period of follow-up. In all, 165 primary total hip replacements, undertaken between July 1984 and June 1987 were followed prospectively. Clinical follow-up included a standardised clinical examination, and radiological assessment was based on a standardised anteroposterior radiograph of the pelvis, which was studied for the presence of osteolysis, debonding and cortical atrophy. Survival of the stem with revision for any reason was 81% (95% confidence interval (CI), 76 to 86) at 20 years and for aseptic loosening 87% (95% CI, 82 to 90). At the 20-year follow-up, 15 of the surviving 36 stems showed no radiological changes. Debonding (p = 0.005), osteolysis (p = 0.003) and linear polyethylene wear (p = 0.016) were associated with aseptic loosening, whereas cortical atrophy was not associated with failure (p = 0.008). The 20-year results of the Müller straight stem are comparable to those of other successful cemented systems with similar follow-up. Radiological changes are frequently observed, but with a low incidence of progression, and rarely result in revision. Cortical atrophy appears to be an effect of ageing and not a sign of loosening of the femoral component.
When fracture of an extensively porous-coated
femoral component occurs, its removal at revision total hip arthroplasty
(THA) may require a femoral osteotomy and the use of a trephine.
The remaining cortical bone after using the trephine may develop
thermally induced necrosis. A retrospective review identified 11
fractured, well-fixed, uncemented, extensively porous-coated femoral
components requiring removal using a trephine with a minimum of
two years of follow-up. The mean time to failure was 4.6 years (1.7 to 9.1, standard
deviation ( A total of four patients (36.4%) required further revision: three
for instability and one for fracture of the revision component.
There was no statistically significant difference in the mean Harris
hip score before implant fracture (82.4; These findings suggest that removal of a fractured, well-fixed,
uncemented, extensively porous-coated femoral component using a
trephine does not compromise subsequent fixation at revision THA
and the patient’s pre-operative level of function can be restored.
However, the loss of proximal bone stock before revision may be associated
with a high rate of dislocation post-operatively. Cite this article:
Dislocation remains among the most common complications
of, and reasons for, revision of both primary and revision total
hip replacements (THR). Hence, there is great interest in maximising
stability to prevent this complication. Head size has been recognised
to have a strong influence on the risk of dislocation post-operatively.
As femoral head size increases, stability is augmented, secondary
to an increase in impingement-free range of movement. Larger head
sizes also greatly increase the ‘jump distance’ required for the
head to dislocate in an appropriately positioned cup. Level-one
studies support the use of larger diameter heads as they decrease
the risk of dislocation following primary and revision THR. Highly cross-linked
polyethylene has allowed us to increase femoral head size, without
a marked increase in wear. However, the thin polyethylene liners
necessary to accommodate larger heads may increase the risk of liner
fracture and larger heads have also been implicated in causing soft-tissue
impingement resulting in groin pain. Larger diameter heads also
impart larger forces on the femoral trunnion, which may contribute
to corrosion, metal release, and adverse local tissue reactions.
Alternative large bearings including large ceramic heads and dual
mobility bearings may mitigate some of these risks, and several
of these devices have been used with clinical success. Cite this article:
The aim of this study was to assess the effect
of frictional torque and bending moment on fretting corrosion at
the taper interface of a modular femoral component and to investigate
whether different combinations of material also had an effect. The
combinations we examined were 1) cobalt–chromium (CoCr) heads on
CoCr stems 2) CoCr heads on titanium alloy (Ti) stems and 3) ceramic
heads on CoCr stems. In test 1 increasing torque was imposed by offsetting the stem
in the anteroposterior plane in increments of 0 mm, 4 mm, 6 mm and
8 mm when the torque generated was equivalent to 0 Nm, 9 Nm, 14
Nm and 18 Nm. In test 2 we investigated the effect of increasing the bending
moment by offsetting the application of axial load from the midline
in the mediolateral plane. Increments of offset equivalent to head
+ 0 mm, head + 7 mm and head + 14 mm were used. Significantly higher currents and amplitudes were seen with increasing
torque for all combinations of material. However, Ti stems showed
the highest corrosion currents. Increased bending moments associated
with using larger offset heads produced more corrosion: Ti stems
generally performed worse than CoCr stems. Using ceramic heads did
not prevent corrosion, but reduced it significantly in all loading
configurations. Cite this article:
