The increased The proximal penetration of the femoral head five years post-operatively
was measured for 15 patients using radiostereometric analysis (RSA).Aims
Patients and Methods
We evaluated clinical and radiographic outcomes of total shoulder
arthroplasty (TSA) using the second-generation Trabecular Metal
(TM) Glenoid component. The first generation component was withdrawn
in 2005 after a series of failures were reported. Between 2009 and
2012, 40 consecutive patients with unilateral TSA using the second-generation
component were enrolled in this clinical study. The mean age of
the patients was 63.8 years (40 to 75) and the mean follow-up was
38 months (24 to 42). Patients were evaluated using the Constant score (CS), the American
Shoulder and Elbow Surgeons (ASES) score and routine radiographs.Aims
Methods
Periprosthetic joint infection (PJI) is a serious complication
of total hip arthroplasty (THA). Different bearing surface materials
have different surface properties and it has been suggested that
the choice of bearing surface may influence the risk of PJI after
THA. The objective of this meta-analysis was to compare the rate
of PJI between metal-on-polyethylene (MoP), ceramic-on-polyethylene
(CoP), and ceramic-on-ceramic (CoC) bearings. Electronic databases (Medline, Embase, Cochrane library, Web
of Science, and Cumulative Index of Nursing and Allied Health Literature)
were searched for comparative randomized and observational studies
that reported the incidence of PJI for different bearing surfaces.
Two investigators independently reviewed studies for eligibility, evaluated
risk of bias, and performed data extraction. Meta-analysis was performed
using the Mantel–Haenzel method and random-effects model in accordance
with methods of the Cochrane group.Aims
Patients and Methods
Malalignment of the tibial component could influence the long-term survival of a total knee arthroplasty (TKA). The object of this study was to investigate the biomechanical effect of varus and valgus malalignment on the tibial component under stance-phase gait cycle loading conditions. Validated finite element models for varus and valgus malalignment by 3° and 5° were developed to evaluate the effect of malalignment on the tibial component in TKA. Maximum contact stress and contact area on a polyethylene insert, maximum contact stress on patellar button and the collateral ligament force were investigated.Objectives
Methods
The ideal bearing surface for young patients
undergoing total hip replacement (THR) remains controversial. We report
the five-year results of a randomised controlled trial comparing
the clinical and radiological outcomes of 102 THRs in 91 patients
who were <
65 years of age. These patients were randomised to
receive a cobalt–chrome on ultra-high-molecular-weight polyethylene,
cobalt–chrome on highly cross-linked polyethylene, or a ceramic-on-ceramic
bearing. In all, 97 hip replacements in 87 patients were available
for review at five years. Two hips had been revised, one for infection
and one for peri-prosthetic fracture. At the final follow-up there were no significant differences
between the groups for the mean Western Ontario and McMaster Universities
osteoarthritis index (pain, p = 0.543; function, p = 0.10; stiffness,
p = 0.99), Short Form-12 (physical component, p = 0.878; mental
component, p = 0.818) or Harris hip scores (p = 0.22). Radiological
outcomes revealed no significant wear in the ceramic group. Comparison of standard and highly cross-linked polyethylene,
however, revealed an almost threefold difference in the mean annual
linear wear rates (0.151 mm/year
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The creep and wear behaviour of highly cross-linked polyethylene and standard polyethylene liners were examined in a prospective, double-blind randomised, controlled trial using radiostereometric analysis. We randomised 54 patients to receive hip replacements with either highly cross-linked polyethylene or standard liners and determined the three-dimensional penetration of the liners over three years. After three years the mean total penetration was 0.35 mm (SD 0.14) for the highly cross-linked polyethylene group and 0.45 mm (SD 0.19) for the standard group. The difference was statistically significant (p = 0.0184). From the pattern of penetration it was possible to discriminate creep from wear. Most (95%) of the creep occurred within six months of implantation and nearly all within the first year. There was no difference in the mean degree of creep between the two types of polyethylene (highly cross-linked polyethylene 0.26 mm, SD 0.17; standard 0.27 mm, SD 0.2; p = 0.83). There was, however, a significant difference (p = 0.012) in the mean wear rate (highly cross-linked polyethylene 0.03 mm/yr, SD 0.06; standard 0.07 mm/yr, SD 0.05). Creep and wear occurred in significantly different directions (p = 0.01); creep was predominantly proximal whereas wear was anterior, proximal and medial. We conclude that penetration in the first six months is creep-dominated, but after one year virtually all penetration is due to wear. Highly cross-linked polyethylene has a 60% lower rate of wear than standard polyethylene and therefore will probably perform better in the long term.
The use of ceramic femoral heads in total hip arthroplasty (THA) has increased due to their proven low bearing wear characteristics. Ceramic femoral heads are also thought to reduce wear and corrosion at the head-stem junction with titanium (Ti) stems when compared with metal heads. We sought to evaluate taper damage of ceramic compared with metal heads when paired with cobalt chromium (CoCr) alloy stems in a single stem design. This retrieval study involved 48 total hip arthroplasties (THAs) with CoCr V40 trunnions paired with either CoCr (n = 21) or ceramic (n = 27) heads. The taper junction of all hips was evaluated for fretting/corrosion damage and volumetric material loss using a roundness-measuring machine. We used linear regression analysis to investigate taper damage differences after adjusting for potential confounding variables.Objectives
Methods
This systematic review of the literature summarises
the clinical experience with ceramic-on-ceramic hip bearings over
the past 40 years and discusses the concerns that exist in relation
to the bearing combination. Loosening, fracture, liner chipping
on insertion, liner canting and dissociation, edge-loading and squeaking
have all been reported, and the relationship between these issues
and implant design and surgical technique is investigated. New design
concepts are introduced and analysed with respect to previous clinical
experience.
The debate whether to use cemented or uncemented
components in primary total hip replacement (THR) has not yet been
considered with reference to the cost implications to the National
Health Service. We obtained the number of cemented and uncemented components
implanted in 2009 from the National Joint Registry for England and
Wales. The cost of each component was established. The initial financial
saving if all were cemented was then calculated. Subsequently the
five-year rates of revision for each type of component were reviewed
and the predicted number of revisions at five years for the actual
components used was compared with the predicted number of revisions
for a cemented THR. This was then multiplied by the mean cost of
revision surgery to provide an indication of the savings over the
first five years if all primary THRs were cemented. The saving at primary THR was calculated to be £10 million with
an additional saving during the first five years of between £5 million
and £8.5 million. The use of cemented components in routine primary
THR in the NHS as a whole can be justified on a financial level
but we recognise individual patient factors must be considered when deciding
which components to use.
Nanometre-sized particles of ultra-high molecular weight polyethylene have been identified in the lubricants retrieved from hip simulators. Tissue samples were taken from seven failed Charnley total hip replacements, digested using strong alkali and analysed using high-resolution field emission gun-scanning electron microscopy to determine whether nanometre-sized particles of polyethylene debris were generated We isolated nanometre-sized particles from the retrieved tissue samples. The smallest identified was 30 nm and the majority were in the 0.1 μm to 0.99 μm size range. Particles in the 1.0 μm to 9.99 μm size range represented the highest proportion of the wear volume of the tissue samples, with 35% to 98% of the total wear volume comprised of particles of this size. The number of nanometre-sized particles isolated from the tissues accounted for only a small proportion of the total wear volume. Further work is required to assess the biological response to nanometre-sized polyethylene particles.
We report on 397 consecutive revision total hip
replacements in 371 patients with a mean clinical and radiological follow-up
of 12.9 years (10 to 17.7). The mean age at surgery was 69 years
(37 to 93). A total of 28 patients (8%) underwent further revision,
including 16 (4%) femoral components. In all 223 patients (56%,
233 hips) died without further revision and 20 patients (5%, 20
hips) were lost to follow-up. Of the remaining patients, 209 (221
hips) were available for clinical assessment and 194 (205 hips)
for radiological review at mean follow-up of 12.9 years (10 to 17.7). The mean Harris Hip Score improved from 58.7 (11 to 92) points
to 80.7 (21 to 100) (p <
0.001) and the mean Merle d’Aubigné and
Postel hip scores at final follow-up were 4.9 (2 to 6), 4.5 (2 to
6) and 4.3 (2 to 6), respectively for pain, mobility and function.
Radiographs showed no lucencies around 186 (90.7%) femoral stems
with stable bony ingrowth seen in 199 stems (97%). The survival
of the S-ROM femoral stem at 15 years with revision for any reason as
the endpoint was 90.5% (95% confidence interval (CI) 85.7 to 93.8)
and with revision for aseptic loosening as the endpoint 99.3% (95%
CI 97.2 to 99.8). We have shown excellent long-term survivorship and good clinical
outcome of a cementless hydroxyapatite proximally-coated modular
femoral stem in revision hip surgery. Cite this article:
Increasing follow-up identifies the outcome in younger patients who have undergone total hip replacement (THR) and reveals the true potential for survival of the prosthesis. We identified 28 patients (39 THRs) who had undergone cemented Charnley low friction arthroplasty between 1969 and 2001. Their mean age at operation was 17.9 years (12 to 19) and the maximum follow-up was 34 years. Two patients (4 THRs) were lost to follow-up, 13 (16 THRs) were revised at a mean period of 19.1 years (8 to 34) and 13 (19 THRs) continue to attend regular follow-up at a mean of 12.6 years (2.3 to 29). In this surviving group one acetabular component was radiologically loose and all femoral components were secure. In all the patients the diameter of the femoral head was 22.225 mm with Charnley femoral components used in 29 hips and C-stem femoral components in ten. In young patients who require THR the acetabular bone stock is generally a limiting factor for the size of the component. Excellent long-term results can be obtained with a cemented polyethylene acetabular component and a femoral head of small diameter.
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Malrotation of the femoral component is a cause of patellofemoral maltracking after total knee arthroplasty. Its precise effect on the patellofemoral mechanics has not been well quantified. We have developed an in vitro method to measure the influence of patellar maltracking on contact. Maltracking was induced by progressively rotating the femoral component either internally or externally. The contact mechanics were analysed using Tekscan. The results showed that excessive malrotation of the femoral component, both internally and externally, had a significant influence on the mechanics of contact. The contact area decreased with progressive maltracking, with a concomitant increase in contact pressure. The amount of contact area that carries more than the yield stress of ultra-high molecular weight polyethylene significantly increases with progressive maltracking. It is likely that the elevated pressures noted in malrotation could cause accelerated and excessive wear of the patellar button.
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We conducted a longitudinal study including patients with the same type of primary hybrid total hip replacement and evaluated patient activity and femoral osteolysis at either five or ten years post-operatively. Activity was measured using the University of California, Los Angeles scale. The primary outcome was the radiological assessment of femoral osteolysis. Secondary outcomes were revision of the femoral component for aseptic loosening and the patients’ quality of life. Of 503 hip replacements in 433 patients with a mean age of 67.7 years (30 to 91), 241 (48%) were seen at five and 262 (52%) at ten years post-operatively. Osteolytic lesions were identified in nine of 166 total hip replacements (5.4%) in patients with low activity, 21 of 279 (7.5%) with moderate activity, and 14 of 58 (24.1%) patients with high activity. The risk of osteolysis increased with participation in a greater number of sporting activities. In multivariate logistic regression adjusting for age, gender, body mass index and the inclination angle of the acetabular component, the adjusted odds ratio for osteolysis comparing high In conclusion, of patients engaged in high activity, 24% had developed femoral osteolysis five to ten years post-operatively.
We have analysed from the Finnish Arthroplasty Register the long-term survivorship of the 12 most commonly-used cemented implants between 1980 and 2005 in patients aged 55 years or older with osteoarthritis. Only two designs of femoral component, the Exeter Universal and the Müller Straight femoral component had a survivorship of over 95% at ten years with revision for aseptic loosening as the endpoint. At 15 years of the femoral and acetabular component combinations, only the Exeter Universal/Exeter All-poly implant had a survival rate of over 90% with revision for aseptic loosening as the endpoint. In the subgroup of patients aged between 55 and 64 years, survivorship overall was less than 90% at ten years. The variation in the long-term rates of survival of different cemented hip implants was considerable in patients aged 55 years or older. In those aged between 55 and 64 years, none of the cemented prostheses studied yielded excellent long-term survival rates (≥ 90% at 15 years).
Studies reporting specifically on squeaking in total hip arthroplasty have focused on cementless, and not on hybrid, fixation. We hypothesised that the cement mantle of the femur might have a damping effect on the sound transmitted through the metal stem. The objective of this study was to test the effect of cement on sound propagation along different stem designs and under different fixation conditions. An Objectives
Methods