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
As the number of younger and more active patients
treated with total knee arthroplasty (TKA) continues to increase,
consideration of better fixation as a means of improving implant
longevity is required. Cemented TKA remains the reference standard
with the largest body of evidence and the longest follow-up to support
its use. However, cementless TKA, may offer the opportunity of a
more bone-sparing procedure with long lasting biological fixation
to the bone. We undertook a review of the literature examining advances
of cementless TKA and the reported results. Cite this article:
Risk of revision following total knee arthroplasty (TKA) is higher
in patients under 55 years, but little data are reported regarding
non-revision outcomes. This study aims to identify predictors of
dissatisfaction in these patients. We prospectively assessed 177 TKAs (157 consecutive patients,
99 women, mean age 50 years; 17 to 54) from 2008 to 2013. Age, gender,
implant, indication, body mass index (BMI), social deprivation,
range of movement, Kellgren-Lawrence (KL) grade of osteoarthritis
(OA) and prior knee surgery were recorded. Pre- and post-operative
Oxford Knee Score (OKS) as well as Short Form-12 physical (PCS)
and mental component scores were obtained. Post-operative range
of movement, complications and satisfaction were measured at one
year.Aims
Patients and Methods
Symptomatic hip osteonecrosis is a disabling
condition with a poorly understood aetiology and pathogenesis. Numerous
treatment options for hip osteonecrosis are described, which include
non-operative management and joint preserving procedures, as well
as total hip replacement (THR). Non-operative or joint preserving
treatment may improve outcomes when an early diagnosis is made before
the lesion has become too large or there is radiographic evidence
of femoral head collapse. The presence of a crescent sign, femoral
head flattening, and acetabular involvement indicate a more advanced-stage
disease in which joint preserving options are less effective than
THR. Since many patients present after disease progression, primary
THR is often the only reliable treatment option available. Prior
to the 1990s, outcomes of THR for osteonecrosis were poor. However,
according to recent reports and systemic reviews, it is encouraging
that with the introduction of newer ceramic and/or highly cross-linked
polyethylene bearings as well as highly-porous fixation interfaces,
THR appears to be a reliable option in the management of end-stage
arthritis following hip osteonecrosis in this historically difficult
to treat patient population. Cite this article:
To assess the responsiveness and ceiling/floor effects of the Forgotten Joint Score -12 and to compare these with that of the more widely used Oxford Hip Score (OHS) in patients six and 12 months after primary total hip arthroplasty. We prospectively collected data at six and 12 months following total hip arthroplasty from 193 patients undergoing surgery at a single centre. Ceiling effects are outlined with frequencies for patients obtaining the lowest or highest possible score. Change over time from six months to 12 months post-surgery is reported as effect size (Cohen’s d).Objectives
Methods
We report a 12- to 15-year implant survival assessment
of a prospective single-surgeon series of Birmingham Hip Resurfacings
(BHRs). The earliest 1000 consecutive BHRs including 288 women (335
hips) and 598 men (665 hips) of all ages and diagnoses with no exclusions
were prospectively followed-up with postal questionnaires, of whom
the first 402 BHRs (350 patients) also had clinical and radiological
review. Mean follow-up was 13.7 years (12.3 to 15.3). In total, 59 patients
(68 hips) died 0.7 to 12.6 years following surgery from unrelated
causes. There were 38 revisions, 0.1 to 13.9 years (median 8.7)
following operation, including 17 femoral failures (1.7%) and seven
each of infections, soft-tissue reactions and other causes. With
revision for any reason as the end-point Kaplan–Meier survival analysis
showed 97.4% (95% confidence interval (CI) 96.9 to 97.9) and 95.8%
(95% CI 95.1 to 96.5) survival at ten and 15 years, respectively.
Radiological assessment showed 11 (3.5%) femoral and 13 (4.1%) acetabular
radiolucencies which were not deemed failures and one radiological
femoral failure (0.3%). Our study shows that the performance of the BHR continues to
be good at 12- to 15-year follow-up. Men have better implant survival
(98.0%; 95% CI 97.4 to 98.6) at 15 years than women (91.5%; 95%
CI 89.8 to 93.2), and women <
60 years (90.5%; 95% CI 88.3 to
92.7) fare worse than others. Hip dysplasia and osteonecrosis are
risk factors for failure. Patients under 50 years with osteoarthritis
fare best (99.4%; 95% CI 98.8 to 100 survival at 15 years), with
no failures in men in this group. Cite this article:
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:
Bariatric surgery has been advocated as a means
of reducing body mass index (BMI) and the risks associated with total
knee arthroplasty (TKA). However, this has not been proved clinically.
In order to determine the impact of bariatric surgery on the outcome
of TKA, we identified a cohort of 91 TKAs that were performed in
patients who had undergone bariatric surgery (bariatric cohort).
These were matched with two separate cohorts of patients who had not
undergone bariatric surgery. One was matched 1:1 with those with
a higher pre-bariatric BMI (high BMI group), and the other was matched
1:2 based on those with a lower pre-TKA BMI (low BMI group). In the bariatric group, the mean BMI before bariatric surgery
was 51.1 kg/m2 (37 to 72), which improved to 37.3 kg/m2 (24
to 59) at the time of TKA. Patients in the bariatric group had a
higher risk of, and worse survival free of, re-operation (hazard
ratio (HR) 2.6; 95% confidence interval (CI) 1.2 to 6.2; p = 0.02)
compared with the high BMI group. Furthermore, the bariatric group
had a higher risk of, and worse survival free of re-operation (HR
2.4; 95% CI 1.2 to 3.3; p = 0.2) and revision (HR 2.2; 95% CI 1.1
to 6.5; p = 0.04) compared with the low BMI group. While bariatric surgery reduced the BMI in our patients, more
analysis is needed before recommending bariatric surgery before
TKA in obese patients. Cite this article:
Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE). A total of ten composite tibias implanted with all-polyethylene (AP) and metal-backed (MB) tibial components were loaded to 2500 N. Cortical strain was measured using DIC and cancellous microdamage using AE. FEMs were created and validated and polyethylene thickness varied from 6 mm to 10 mm. The volume of cancellous bone exposed to < -3000 µε (pathological loading) and < -7000 µε (yield point) minimum principal (compressive) microstrain and > 3000 µε and > 7000 µε maximum principal (tensile) microstrain was computed.Objectives
Materials and Methods
Partial knee arthroplasty (PKA), either medial
or lateral unicompartmental knee artroplasty (UKA) or patellofemoral arthroplasty
(PFA) are a good option in suitable patients and have the advantages
of reduced operative trauma, preservation of both cruciate ligaments
and bone stock, and restoration of normal kinematics within the
knee joint. However, questions remain concerning long-term survival.
The goal of this review article was to present the long-term results
of medial and lateral UKA, PFA and combined compartmental arthroplasty
for multicompartmental disease. Medium- and long-term studies suggest
reasonable outcomes at ten years with survival greater than 95% in
UKA performed for medial osteoarthritis or osteonecrosis, and similarly
for lateral Cite this article:
The June 2015 Trauma Roundup360 looks at: HIV-related implant surgery in trauma; Major transfusion under the spotlight; Surgery and mortality in elderly acetabular fractures; Traction pin safety; Obesity and trauma; Salvage of acetabular fixation in the longer term
This randomised trial evaluated the outcome of
a single design of unicompartmental arthroplasty of the knee (UKA) with
either a cemented all-polyethylene or a metal-backed modular tibial
component. A total of 63 knees in 45 patients (17 male, 28 female)
were included, 27 in the all-polyethylene group and 36 in the metal-backed
group. The mean age was 57.9 years (39.6 to 76.9). At a mean follow-up
of 6.4 years (5 to 9.9), 11 all-polyethylene components (41%) were
revised (at a mean of 5.8 years; 1.4 to 8.0) post-operatively and
two metal-backed components were revised (at one and five years).
One revision in both groups was for unexplained pain, one in the
metal-backed group was for progression of osteoarthritis. The others
in the all-polyethylene group were for aseptic loosening. The survivorship
at seven years calculated by the Kaplan–Meier method for the all-polyethylene
group was 56.5% (95% CI 31.9 to 75.2, number at risk 7) and for
the metal-backed group was 93.8% (95% CI 77.3 to 98.4, number at
risk 16) This difference was statistically significant (p <
0.001).
At the most recent follow-up, significantly better mean Western
Ontario and McMaster Universities Arthritis Index Scores were found
in the all-polyethylene group (13.4 This randomised study demonstrates that all-polyethylene components
in this design of fixed bearing UKA had unsatisfactory results with
significantly higher rates of failure before ten years compared
with the metal-back components. Cite this article:
Hip resurfacing arthroplasty (HRA) is an alternative to conventional
total hip arthroplasty for patients with osteonecrosis (ON) of the
femoral head. Our aim was to report the long-term outcome of HRA,
which is not currently known. Long-term survivorship, clinical scores and radiographic results
for 82 patients (99 hips) treated with HRA for ON over a period
of 18 years were reviewed retrospectively. The mean age of the 67
men and 15 women at the time of surgery was 40.8 years (14 to 64).
Patients were resurfaced regardless of the size of the osteonecrotic
lesion.Aims
Patients and Methods
Metal-on-metal resurfacing of the hip (MoMHR)
has enjoyed a resurgence in the last decade, but is now again in question
as a routine option for osteoarthritis of the hip. Proponents of
hip resurfacing suggest that its survival is superior to that of
conventional hip replacement (THR), and that hip resurfacing is
less invasive, is easier to revise than THR, and provides superior
functional outcomes. Our argument serves to illustrate that none
of these proposed advantages have been realised and new and unanticipated
serious complications, such as pseudotumors, have been associated
with the procedure. As such, we feel that the routine use of MoMHR
is not justified. Cite this article:
Mechanical alignment has been a fundamental tenet of total knee arthroplasty (TKA) since modern knee replacement surgery was developed in the 1970s. The objective of mechanical alignment was to infer the greatest biomechanical advantage to the implant to prevent early loosening and failure. Over the last 40 years a great deal of innovation in TKA technology has been focusing on how to more accurately achieve mechanical alignment. Recently the concept of mechanical alignment has been challenged, and other alignment philosophies are being explored with the intention of trying to improve patient outcomes following TKA. This article examines the evolution of the mechanical alignment concept and whether there are any viable alternatives.
This editorial considers the shortcomings of assessing outcome after joint replacement only by the survival of the implant.
Isolated patellofemoral arthritis is a common
condition and there are varying opinions on the most effective treatments.
Non-operative and operative treatments have failed to demonstrate
effective long-term treatment for those in an advanced stage of
the condition. Newer designs and increased technology in patellofemoral replacement
(PFR) have produced more consistent outcomes. This has led to a
renewed enthusiasm for this procedure. Newer PFR prostheses have
addressed the patellar maltracking issues plaguing some of the older designs.
Short-term results with contemporary prostheses and new technology
are described here. Cite this article: