The pre-operative level of haemoglobin is the strongest predictor
of the peri-operative requirement for blood transfusion after total
knee arthroplasty (TKA). There are, however, no studies reporting
a value that could be considered to be appropriate pre-operatively. This study aimed to identify threshold pre-operative levels of
haemoglobin that would predict the requirement for blood transfusion
in patients who undergo TKA. Analysis of receiver operator characteristic (ROC) curves of
2284 consecutive patients undergoing unilateral TKA was used to
determine gender specific thresholds predicting peri-operative transfusion
with the highest combined sensitivity and specificity (area under
ROC curve 0.79 for males; 0.78 for females).Aims
Patients and Methods
The December 2014 Knee Roundup360 looks at: national guidance on arthroplasty thromboprophylaxis is effective; unicompartmental knee replacement has the edge in terms of short-term complications; stiff knees, timing and manipulation; neuropathic pain and total knee replacement; synovial fluid α-defensin and CRP: a new gold standard in joint infection diagnosis?; how to assess anterior knee pain?; where is the evidence? Five new implants under the spotlight; and a fresh look at ACL reconstruction
The rate of peri-prosthetic infection following
total joint replacement continues to rise, and attempts to curb
this trend have included the use of antibiotic-loaded bone cement
at the time of primary surgery. We have investigated the clinical-
and cost-effectiveness of the use of antibiotic-loaded cement for
primary total knee replacement (TKR) by comparing the rate of infection
in 3048 TKRs performed without loaded cement over a three-year period The absolute rate of infection increased when antibiotic-loaded
cement was used in TKR. However, this rate of increase was less
than the rate of increase in infection following uncemented THR
during the same period. If the rise in the rate of infection observed
in THR were extrapolated to the TKR cohort, 18 additional cases
of infection would have been expected to occur in the cohort receiving
antibiotic-loaded cement, compared with the number observed. Depending
on the type of antibiotic-loaded cement that is used, its cost in
all primary TKRs ranges between USD $2112.72 and USD $112 606.67
per case of infection that is prevented. Cite this article:
The objective of this study was to determine if combining variations in mixing technique of antibiotic-impregnated polymethylmethacrylate (PMMA) cement with low frequency ultrasound (LFUS) improves antibiotic elution during the initial high phase (Phase I) and subsequent low phase (Phase II) while not diminishing mechanical strength. Three batches of vancomycin-loaded PMMA were prepared with different mixing techniques: a standard technique; a delayed technique; and a control without antibiotic. Daily elution samples were analysed using flow injection analysis (FIA). Beginning in Phase II, samples from each mix group were selected randomly to undergo either five, 15, 45, or 0 minutes of LFUS treatment. Elution amounts between LFUS treatments were analysed. Following Phase II, compression testing was done to quantify strength. Objectives
Methods
The August 2014 Knee Roundup360 looks at: re-admission following total knee replacement; out with the old and in with the new? computer navigation revisited; approach less important in knee replacement; is obesity driving a rise in knee replacements?; knee replacement isn’t cheap in the obese; cruciate substitution doesn’t increase knee flexion; and sonication useful diagnostic aid in two-stage revision.
The December 2015 Knee Roundup360 looks at: Albumin and complications in knee arthroplasty; Tantalum: a knee fixation for all seasons?; Dynamic knee alignment; Tibial component design in UKA; Managing the tidal wave of revision knee arthroplasty; Scoring pain in TKR; Does anyone have a ‘normal’ tibial slope?; XLPE in TKR? A five-year clinical study; Spacers and infected revision arthroplasties; Dialysis and arthroplasty
The purpose of this study was to compare clinical
outcomes of total knee arthroplasty (TKA) after manipulation under
anaesthesia (MUA) for post-operative stiffness with a matched cohort
of TKA patients who did not requre MUA. In total 72 patients (mean age 59.8 years, 42 to 83) who underwent
MUA following TKA were identified from our prospective database
and compared with a matched cohort of patients who had undergone
TKA without subsequent MUA. Patients were evaluated for range of
movement (ROM) and clinical outcome scores (Western Ontario and
McMaster Universities Arthritis Index, Short-Form Health Survey,
and Knee Society Clinical Rating System) at a mean follow-up of
36.4 months (12 to 120). MUA took place at a mean of nine weeks
(5 to 18) after TKA. In patients who required MUA, mean flexion
deformity improved from 10° (0° to 25°) to 4.4° (0° to 15°) (p <
0.001),
and mean range of flexion improved from 79.8° (65° to 95°) to 116°
(80° to 130°) (p <
0.001). There were no statistically significant
differences in ROM or functional outcome scores at three months,
one year, or two years between those who required MUA and those
who did not. There were no complications associated with manipulation At most recent follow-up, patients requiring MUA achieved equivalent
ROM and clinical outcome scores when compared with a matched control
group. While other studies have focused on ROM after manipulation,
the current study adds to current literature by supplementing this
with functional outcome scores. Cite this article:
Bactericidal levels of antibiotics are difficult
to achieve in infected total joint arthroplasty when intravenous antibiotics
or antibiotic-loaded cement spacers are used, but intra-articular
(IA) delivery of antibiotics has been effective in several studies.
This paper describes a protocol for IA delivery of antibiotics in
infected knee arthroplasty, and summarises the results of a pharmacokinetic
study and two clinical follow-up studies of especially difficult
groups: methicillin-resistant Cite this article:
The October 2015 Knee Roundup360 looks at: Allergy and outcome in arthroplasty; Physiotherapy and drains not such a bad combination?; Another nail in the coffin for arthroscopists?; Graft precondition hocus pocus; Extended dose steroids in knee arthritis?; Indolent peri-prosthetic infection; Computer modelling and medial knee arthritis
Oxidised zirconium was introduced as a material for femoral components
in total knee arthroplasty (TKA) as an attempt to reduce polyethylene
wear. However, the long-term survival of this component is not known. We performed a retrospective review of a prospectively collected
database to assess the ten year survival and clinical and radiological
outcomes of an oxidised zirconium total knee arthroplasty with the
Genesis II prosthesis. The Western Ontario and McMaster Universities Osteoarthritis
Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS)
and a patient satisfaction scale were used to assess outcome.Aims
Methods
A small proportion of patients have persistent
pain after total knee replacement (TKR). The primary aim of this study
was to record the prevalence of pain after TKR at specific intervals
post-operatively and to ascertain the impact of neuropathic pain.
The secondary aim was to establish any predictive factors that could
be used to identify patients who were likely to have high levels
of pain or neuropathic pain after TKR. A total of 96 patients were included in the study. Their mean
age was 71 years (48 to 89); 54 (56%) were female. The mean follow-up
was 46 months (39 to 51). Pre-operative demographic details were
recorded including a Visual Analogue Score (VAS) for pain, the Hospital
Anxiety and Depression score as well as the painDETECT score for neuropathic
pain. Functional outcome was assessed using the Oxford Knee score. The mean pre-operative VAS was 5.8 (1 to 10); and it improved
significantly at all time periods post-operatively (p <
0.001):
(from 4.5 at day three to five (1 to 10), 3.2 at six weeks (0 to
9), 2.4 at three months (0 to 7), 2.0 at six months (0 to 9), 1.7
at nine months (0 to 9), 1.5 at one year (0 to 8) and 2.0 at mean
46 months (0 to 10)). There was a high correlation (r >
0.7; p <
0.001) between the mean VAS scores for pain and the mean painDETECT
scores at three months, one year and three years post-operatively.
There was no correlation between the pre-operative scores and any
post-operative scores at any time point. We report the prevalence of pain and neuropathic pain at various
intervals up to three years after TKR. Neuropathic pain is an underestimated
problem in patients with pain after TKR. It peaks at between six
weeks and three-months post-operatively. However, from these data
we were unable to predict which patients are most likely to be affected. Cite this article:
A soft-tissue defect over an infected total knee
replacement (TKR) presents a difficult technical problem that can
be treated with a gastrocnemius flap, which is rotated over the
defect during the first-stage of a revision procedure. This facilitates
wound healing and the safe introduction of a prosthesis at the second
stage. We describe the outcome at a mean follow-up of 4.5 years
(1 to 10) in 24 patients with an infected TKR who underwent this procedure.
A total of 22 (92%) eventually obtained a satisfactory result. The
mean Knee Society score improved from 53 pre-operatively to 103
at the latest follow-up (p <
0.001). The mean Western Ontario
and McMaster Universities osteoarthritis index and Short-Form 12
score also improved significantly (p <
0.001). This form of treatment can be used reliably and safely to treat
many of these complex cases where control of infection, retention
of the components and acceptable functional recovery are the primary
goals. Cite this article:
Analysis of the morphology of the distal femur, and by extension
of the femoral components in total knee arthroplasty (TKA), has
largely been related to the aspect ratio, which represents the width
of the femur. Little is known about variations in trapezoidicity
(i.e. whether the femur is more rectangular or more trapezoidal).
This study aimed to quantify additional morphological characteristics
of the distal femur and identify anatomical features associated
with higher risks of over- or under-sizing of components in TKA. We analysed the shape of 114 arthritic knees at the time of primary
TKA using the pre-operative CT scans. The aspect ratio and trapezoidicity
ratio were quantified, and the post-operative prosthetic overhang
was calculated. We compared the morphological characteristics with
those of 12 TKA models.Aims
Methods
Haematomas, drainage, and other non-infectious
wound complications following total knee replacement (TKR) have
been associated with long-term sequelae, in particular, deep infection.
However, the impact of these wound complications on clinical outcome
is unknown. This study compares results in 15 patients re-admitted
for wound complications within 90 days of TKR to 30 matched patients
who underwent uncomplicated total knee replacements. Patients with
wound complications had a mean age of 66 years (49 to 83) and mean
body mass index (BMI) of 37 (21 to 54), both similar to that of
patients without complications (mean age 65 years and mean BMI 35). Those
with complications had lower mean Knee Society function scores (46
(0 to 100 Cite this article:
Periprosthetic joint infection (PJI) is a devastating
complication for patients and results in greatly increased costs
of care for both healthcare providers and patients. More than 15
500 revision hip and knee procedures were recorded in England, Wales
and Northern Ireland in 2013, with infection accounting for 13%
of revision hip and 23% of revision knee procedures. We report our experience of using antibiotic eluting absorbable
calcium sulphate beads in 15 patients (eight men and seven women
with a mean age of 64.8 years; 41 to 83) as part of a treatment
protocol for PJI in revision arthroplasty. The mean follow-up was 16 months (12 to 22). We report the outcomes
and complications, highlighting the risk of hypercalcaemia which
occurred in three patients. We recommend that serum levels of calcium be routinely sought
following the implantation of absorbable calcium sulphate beads
in orthopaedic surgery. Cite this article:
There is a large amount of evidence available
about the relative merits of unicompartmental and total knee arthroplasty
(UKA and TKA). Based on the same evidence, different people draw
different conclusions and as a result, there is great variability
in the usage of UKA. The revision rate of UKA is much higher than TKA and so some
surgeons conclude that UKA should not be performed. Other surgeons
believe that the main reason for the high revision rate is that
UKA is easy to revise and, therefore, the threshold for revision
is low. They also believe that UKA has many advantages over TKA
such as a faster recovery, lower morbidity and mortality and better
function. They therefore conclude that UKA should be undertaken
whenever appropriate. The solution to this argument is to minimise the revision rate
of UKA, thereby addressing the main disadvantage of UKA. The evidence
suggests that this will be achieved if surgeons use UKA for at least
20% of their knee arthroplasties and use implants that are appropriate
for these broad indications. Cite this article:
We wanted to investigate regional variations in the organisms
reported to be causing peri-prosthetic infections and to report
on prophylaxis regimens currently in use across England. Analysis of data routinely collected by Public Health England’s
(PHE) national surgical site infection database on elective primary
hip and knee arthroplasty procedures between April 2010 and March
2013 to investigate regional variations in causative organisms.
A separate national survey of 145 hospital Trusts (groups of hospitals
under local management) in England routinely performing primary
hip and/or knee arthroplasty was carried out by standard email questionnaire.Objectives
Methods
Total knee replacement (TKR) is an operation
that can be performed with or without the use of a tourniquet. Meta-analyses
of the available Level-1 studies have demonstrated that the use
of a tourniquet leads to a significant reduction in blood loss.
The opponents for use of a tourniquet cite development of complications
such as skin bruising, neurovascular injury, and metabolic disturbance
as drawbacks. Although there may certainly be reason for concern
in arteriopathic patients, there is little evidence that routine
use of a tourniquet during TKR results in any of the above complications.
The use of a tourniquet, on the other hand, provides a bloodless
field that allows the surgeon to perform the procedure with expediency
and optimal visualisation. Blood conservation has gained great importance
in recent years due to increased understanding of the problems associated
with blood transfusion, such as increased surgical site infection
(due to immunomodulation effect), increased length of hospital stay
and increased cost. Based on the authors’ understanding of the available
evidence, the routine use of a tourniquet during TKR is justified
as good surgical practice. Cite this article:
This study reports on the first 150 consecutive
Oxford cementless unicompartmental knee arthroplasties (UKA) performed
in an independent centre (126 patients). All eligible patients had
functional scores (Oxford knee score and high activity arthroplasty
score) recorded pre-operatively and at two- and five-years of follow-up. Fluoroscopically
aligned radiographs were taken at five years and analysed for any
evidence of radiolucent lines (RLLs), subsidence or loosening. The
mean age of the cohort was 63.6 years (39 to 86) with 81 (53.1%)
males. Excellent functional scores were maintained at five years
and there were no progressive RLLs demonstrated on radiographs.
Two patients underwent revision to a total knee arthroplasty giving
a revision rate of 0.23/100 (95% confidence interval 0.03 to 0.84)
component years with overall component survivorship of 98.7% at
five years. There were a further four patients who underwent further
surgery on the same knee, two underwent bearing exchanges for dislocation
and two underwent lateral UKAs for disease progression. This was
a marked improvement from other UKAs reported in New Zealand Joint
Registry data and supports the designing centre’s early results. Cite this article:
The aim of this study was to analyse the gait
pattern, muscle force and functional outcome of patients who had undergone
replacement of the proximal tibia for tumour and alloplastic reconstruction
of the extensor mechanism using the patellar-loop technique. Between February 1998 and December 2009, we carried out wide
local excision of a primary sarcoma of the proximal tibia, proximal
tibial replacement and reconstruction of the extensor mechanism
using the patellar-loop technique in 18 patients. Of these, nine
were available for evaluation after a mean of 11.6 years (0.5 to
21.6). The strength of the knee extensors was measured using an
Isobex machine and gait analysis was undertaken in our gait assessment
laboratory. Functional outcome was assessed using the American Knee
Society (AKS) and Musculoskeletal Tumor Society (MSTS) scores. The gait pattern of the patients differed in ground contact time,
flexion heel strike, maximal flexion loading response and total
sagittal plane excursion. The mean maximum active flexion was 91°
(30° to 110°). The overall mean extensor lag was 1° (0° to 5°).
The mean extensor muscle strength was 25.8% (8.3% to 90.3%) of that
in the non-operated leg (p <
0.001). The mean functional scores
were 68.7% (43.4% to 83.3%) (MSTS) and 71.1 (30 to 90) (AKS functional
score). In summary, the results show that reconstruction of the extensor
mechanism using this technique gives good biomechanical and functional
results. The patients’ gait pattern is close to normal, except for
a somewhat stiff knee gait pattern. The strength of the extensor
mechanism is reduced, but sufficient for walking. Cite this article: