Infection following total hip or knee arthroplasty is a serious
complication. We noted an increase in post-operative infection in
cases carried out in temporary operating theatres. We therefore
compared those cases performed in standard and temporary operating
theatres and examined the deep periprosthetic infection rates. A total of 1223 primary hip and knee arthroplasties were performed
between August 2012 and June 2013. A total of 539 (44%) were performed
in temporary theatres. The two groups were matched for age, gender,
body mass index and American Society of Anesthesiologists grade.Aims
Patients and methods
Our aim was to evaluate the radiographic characteristics of patients
undergoing total hip arthroplasty (THA) for the potential of posterior
bony impingement using CT simulations. Virtual CT data from 112 patients who underwent THA were analysed.
There were 40 men and 72 women. Their mean age was 59.1 years (41
to 76). Associations between radiographic characteristics and posterior
bony impingement and the range of external rotation of the hip were
evaluated. In addition, we investigated the effects of pelvic tilt
and the neck/shaft angle and femoral offset on posterior bony impingement.Aims
Patients and Methods
The aim of this study was to determine whether the sequential
application of povidone iodine-alcohol (PVI) followed by chlorhexidine
gluconate-alcohol (CHG) would reduce surgical wound contamination
to a greater extent than PVI applied twice in patients undergoing
spinal surgery. A single-centre, interventional, two arm, parallel group randomised
controlled trial was undertaken, involving 407 patients who underwent
elective spinal surgery. For 203 patients, the skin was disinfected before surgery using
PVI (10% [w/w (1% w/w available iodine)] in 95% industrial denatured
alcohol, povidone iodine; Videne Alcoholic Tincture) twice, and
for 204 patients using PVI once followed by CHG (2% [w/v] chlorhexidine
gluconate in 70% [v/v] isopropyl alcohol; Chloraprep with tint).
The primary outcome measure was contamination of the wound determined
by aerobic and anaerobic bacterial growth from samples taken after
disinfection.Aims
Patients and Methods
Periprosthetic fracture is a significant complication of total
hip and knee arthroplasty. This study aimed to describe the survival
of patients sustaining periprosthetic femoral fractures and compare
this with that of the general population, as well as to identify
the factors that influence survival. A total of 151 patients (women: men 116:35, mean age 74.6 years,
standard deviation 11.5) that sustained a periprosthetic fracture
between January 2005 and October 2012 were retrospectively analysed.
Epidemiological data, comorbidities, type of surgical management,
type of implant, and mortality data were studied.Aims
Patients and Methods
Hip hemiarthroplasty is a standard treatment for intracapsular
proximal femoral fractures in the frail elderly. In this study we
have explored the implications of early return to theatre, within
30 days, on patient outcome following hip hemiarthroplasty. We retrospectively reviewed the hospital records of all hip hemiarthroplasties
performed in our unit between January 2010 and January 2015. Demographic
details, medical backround, details of the primary procedure, complications,
subsequent procedures requiring return to theatre, re-admissions,
discharge destination and death were collected.Aims
Patients and Methods
Pathological assessment of periprosthetic tissues is important, not only for diagnosis, but also for understanding the pathobiology of implant failure. The host response to wear particle deposition in periprosthetic tissues is characterised by cell and tissue injury, and a reparative and inflammatory response in which there is an innate and adaptive immune response to the material components of implant wear. Physical and chemical characteristics of implant wear influence the nature of the response in periprosthetic tissues and account for the development of particular complications that lead to implant failure, such as osteolysis which leads to aseptic loosening, and soft-tissue necrosis/inflammation, which can result in pseudotumour formation. The innate response involves phagocytosis of implant-derived wear particles by macrophages; this is determined by pattern recognition receptors and results in expression of cytokines, chemokines and growth factors promoting inflammation and osteoclastogenesis; phagocytosed particles can also be cytotoxic and cause cell and tissue necrosis. The adaptive immune response to wear debris is characterised by the presence of lymphoid cells and most likely occurs as a result of a cell-mediated hypersensitivity reaction to cell and tissue components altered by interaction with the material components of particulate wear, particularly metal ions released from cobalt-chrome wear particles. Cite this article: Professor N. A. Athanasou. The pathobiology and pathology of aseptic implant failure.
Fractures of the distal femur can be challenging to manage and
are on the increase in the elderly osteoporotic population. Management
with casting or bracing can unacceptably limit a patient’s ability
to bear weight, but historically, operative fixation has been associated
with a high rate of re-operation. In this study, we describe the outcomes
of fixation using modern implants within a strategy of early return
to function. All patients treated at our centre with lateral distal femoral
locking plates (LDFLP) between 2009 and 2014 were identified. Fracture
classification and operative information including weight-bearing
status, rates of union, re-operation, failure of implants and mortality
rate, were recorded.Aims
Patients and Methods
Patients seeking cervical spine surgery are thought to be increasing
in age, comorbidities and functional debilitation. The changing
demographics of this population may significantly impact the outcomes
of their care, specifically with regards to complications. In this
study, our goals were to determine the rates of functionally dependent
patients undergoing elective cervical spine procedures and to assess
the effect of functional dependence on 30-day morbidity and mortality
using a large, validated national cohort. A retrospective analysis of the American College of Surgeons
National Surgical Quality Improvement Program data files from 2006
to 2013 was conducted to identify patients undergoing common cervical
spine procedures. Multivariate logistic regression models were generated
to analyse the independent association of functional dependence
with 30-day outcomes of interest.Aims
Patients and Methods
A contact patch to rim (CPR) distance of <
10 mm has been
associated with edge-loading and excessive wear. However, not all
arthroplasties with a low CPR distance show problems with wear.
Therefore, CPR distance may not be the only variable affecting the
post-operative metal ion concentrations. We used multiple logistic regression to determine what variables
differed between the patients who had high and low cobalt (CoS)
and chromium (CrS) serum ion concentrations within a cohort of patients
with low (<
10 mm) CPR distances. A total of 56 patients treated
with unilateral hip resurfacing arthroplasty (HRA) had CoS and CrS
ion studies performed more than one year after surgery. The mean
age of the patients at the time of surgery was 51.7 years (29 to
70), with 38 women (68%) and 18 men (32%).Aims
Patients and Methods
The number of revision total knee arthroplasties (TKA) that are
performed is expected to increase. However, previous reports of
the causes of failure after TKA are limited in that they report
the causes at specific institutions, which are often dependent on
referral patterns. Our aim was to report the most common indications
for re-operations and revisions in a large series of posterior-stabilised
TKAs undertaken at a single institution, excluding referrals from
elsewhere, which may bias the causes of failure. A total of 5098 TKAs which were undertaken between 2000 and 2012
were included in the study. Re-operations, revisions with modular
component exchange, and revisions with non-modular component replacement
or removal were identified from the medical records. The mean follow-up
was five years (two to 12).Aims
Patients and Methods
Ultraviolet (UV) light-mediated photofunctionalisation is known to improve osseointegration of pure titanium (Ti). However, histological examination of titanium alloy (Ti6Al4V), which is frequently applied in orthopaedic and dental surgery, has not yet been performed. This study examined the osseointegration of photofunctionalised Ti6Al4V implants. Ti and Ti6Al4V implants were treated with UV light, and the chemical composition and contact angle on the surfaces were evaluated to confirm photofunctionalisation. The implants were inserted into femurs in rats, and the rats were killed two or four weeks after the surgery. For histomorphometric analysis, both the bone–implant contact (BIC) ratio and the bone volume (BV) ratio were calculated from histological analysis and microcomputed tomography data.Objectives
Methods
In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes. We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject–specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year.Objectives
Patients and Methods
Lumbar fusion is known to reduce the variation in pelvic tilt
between standing and sitting. A flexible lumbo-pelvic unit increases
the stability of total hip arthroplasty (THA) when seated by increasing
anterior clearance and acetabular anteversion, thereby preventing
impingement of the prosthesis. Lumbar fusion may eliminate this protective
pelvic movement. The effect of lumbar fusion on the stability of
total hip arthroplasty has not previously been investigated. The Medicare database was searched for patients who had undergone
THA and spinal fusion between 2005 and 2012. PearlDiver software
was used to query the database by the International Classification
of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedural
code for primary THA and lumbar spinal fusion. Patients who had
undergone both lumbar fusion and THA were then divided into three
groups: 1 to 2 levels, 3 to 7 levels and 8+ levels of fusion. The
rate of dislocation in each group was established using ICD-9-CM codes.
Patients who underwent THA without spinal fusion were used as a
control group. Statistical significant difference between groups
was tested using the chi-squared test, and significance set at p
<
0.05.Aims
Patients and Methods
It may not be possible to undertake revision total hip arthroplasty
(THA) in the presence of massive loss of acetabular bone stock using
standard cementless hemispherical acetabular components and metal
augments, as satisfactory stability cannot always be achieved. We
aimed to study the outcome using a reconstruction cage and a porous
metal augment in these patients. A total of 22 acetabular revisions in 19 patients were performed
using a combination of a reconstruction cage and porous metal augments.
The augments were used in place of structural allografts. The mean
age of the patients at the time of surgery was 70 years (27 to 85)
and the mean follow-up was 39 months (27 to 58). The mean number
of previous THAs was 1.9 (1 to 3). All patients had segmental defects
involving more than 50% of the acetabulum and seven hips had an
associated pelvic discontinuity. Aims
Patients and Methods
To investigate the outcomes of treatment of streptococcal periprosthetic
joint infection (PJI) involving total knee and hip arthroplasties. Streptococcal PJI episodes which occurred between January 2009
and December 2015 were identified from clinical databases. Presentation
and clinical outcomes for 30 streptococcal PJIs in 30 patients (12
hip and 18 knee arthroplasties) following treatment were evaluated
from the medical notes and at review. The Kaplan-Meier survival method
was used to estimate the probability of infection-free survival.
The influence of the biofilm active antibiotic rifampin was also
assessed.Aims
Patients and Methods
Long-term clinical outcomes for ceramic-on-ceramic (CoC) bearings
are encouraging. However, there is a risk of squeaking. Guidelines
for the orientation of the acetabular component are defined from
static imaging, but the position of the pelvis and thus the acetabular
component during activities associated with edge-loading are likely
to be very different from those measured when the patient is supine.
We assessed the functional orientation of the acetabular component. A total of 18 patients with reproducible squeaking in their CoC
hips during deep flexion were investigated with a control group
of 36 non-squeaking CoC hips. The two groups were matched for the
type of implant, the orientation of the acetabular component when
supine, the size of the femoral head, ligament laxity, maximum hip
flexion and body mass index. Aims
Patients and Methods
