A high radiographic inclination angle (RI) contributes
to accelerated wear and has been associated with dislocation after
total hip arthroplasty (THA). With freehand positioning of the acetabular
component there is a lack of accuracy, with a trend towards a high
radiographic inclination angle. The aim of this study was to investigate
whether the use of a digital protractor to measure the operative
inclination angle (OI) could improve the positioning of the acetabular
component in relation to a ‘safe zone’. We measured the radiographic inclination angles of 200 consecutive
uncemented primary THAs. In the first 100 the component was introduced
freehand and in the second 100 a digital protractor was used to
measure the operative inclination angle. The mean difference between the operative and the radiographic
inclination angles
(∆RI–OI) in the second cohort was 12.3° (3.8° to 19.8°). There was
a strong correlation between the circumference of the hip and ∆RI–OI.
The number of RI outliers was significantly reduced in the protractor
group (p = 0.002). Adjusting the OI, using a digital protractor and taking into
account the circumference of the patient’s hip, improves the RI
significantly (p <
0.001) and does not require additional operating
time. Cite this article:
There is little evidence on the cost effectiveness
of different brands of hip prostheses. We compared lifetime cost effectiveness
of frequently used brands within types of prosthesis including cemented
(Exeter V40 Contemporary, Exeter V40 Duration and Exeter V40 Elite
Plus Ogee), cementless (Corail Pinnacle, Accolade Trident, and Taperloc Exceed)
and hybrid (Exeter V40 Trilogy, Exeter V40 Trident, and CPT Trilogy).
We used data from three linked English national databases to estimate
the lifetime risk of revision, quality-adjusted life years (QALYs)
and cost. For women with osteoarthritis aged 70 years, the Exeter V40 Elite
Plus Ogee had the lowest risk of revision (5.9% revision risk, 9.0
QALYs) and the CPT Trilogy had the highest QALYs (10.9% revision
risk, 9.3 QALYs). Compared with the Corail Pinnacle (9.3% revision
risk, 9.22 QALYs), the most commonly used brand, and assuming a
willingness-to-pay of £20 000 per QALY gain, the CPT Trilogy is
most cost effective, with an incremental net monetary benefit of £876.
Differences in cost effectiveness between the hybrid CPT Trilogy
and Exeter V40 Trident and the cementless Corail Pinnacle and Taperloc
Exceed were small, and a cautious interpretation is required, given
the limitations of the available information. However, it is unlikely that cemented brands are among the most
cost effective. Similar patterns of results were observed for men
and other ages. The gain in quality of life after total hip arthroplasty,
rather than the risk of revision, was the main driver of cost effectiveness. Cite this article:
The recognition of hips at risk of displacement
in children with cerebral palsy (CP) is a difficult problem for
the orthopaedic surgeon. The Gross Motor Function Classification
System (GMFCS) and head–shaft angle (HSA) are prognostic factors
for hip displacement. However, reference values for HSA are lacking.
This study describes and compares the development of HSA in normal
hips and children with CP. We selected 33 children from a retrospective cohort with unilateral
developmental dysplasia of the hip (DDH) (five boys, 28 girls) and
50 children (35 boys, 15 girls) with CP with GMFCS levels II to
V. HSA of normal developing hips was measured at the contralateral
hip of unilateral DDH children (33 hips) and HSA of CP children
was measured in both hips (100 hips). Measurements were taken from
the radiographs of the children at age two, four and seven years.
The normal hip HSA decreased by 2° per year (p <
0.001). In children
with CP with GMFCS levels II and III HSA decreased by 0.6° (p =
0.046) and 0.9° (p = 0.049) per year, respectively. The HSA did
not alter significantly in GMFCS levels IV and V. Between the ages of two and eight years, the HSA decreases in
normal hips and CP children with GMFCS level, II to III but does
not change in GMFCS levels IV to V. As HSA has a prognostic value
for hip displacement, these reference values may help the orthopaedic
surgeon to predict future hip displacement in children with CP. Cite this article:
Patients with multiple myeloma (MM) develop deposits in the spine
which may lead to vertebral compression fractures (VCFs). Our aim
was to establish which spinopelvic parameters are associated with
the greatest disability in patients with spinal myeloma and VCFs. We performed a retrospective cross-sectional review of 148 consecutive
patients (87 male, 61 female) with spinal myeloma and analysed correlations
between spinopelvic parameters and patient-reported outcome scores.
The mean age of the patients was 65.5 years (37 to 91) and the mean
number of vertebrae involved was 3.7 (1 to 15).Aims
Patients and Methods
Pelvic obliquity is a common finding in adolescents
with cerebral palsy, however, there is little agreement on its measurement
or relationship with hip development at different gross motor function
classification system (GMFCS) levels. The purpose of this investigation was to study these issues in
a large, population-based cohort of adolescents with cerebral palsy
at transition into adult services. The cohort were a subset of a three year birth cohort (n = 98,
65M: 33F, with a mean age of 18.8 years (14.8 to 23.63) at their
last radiological review) with the common features of a migration
percentage greater than 30% and a history of adductor release surgery. Different radiological methods of measuring pelvic obliquity
were investigated in 40 patients and the angle between the acetabular
tear drops (ITDL) and the horizontal reference frame of the radiograph
was found to be reliable, with good face validity. This was selected
for further study in all 98 patients. The median pelvic obliquity was 4° (interquartile range 2° to
8°). There was a strong correlation between hip morphology and the
presence of pelvic obliquity (effect of ITDL on Sharpe’s angle in
the higher hip; rho 7.20 (5% confidence interval 5.59 to 8.81, p
<
0.001). This was particularly true in non-ambulant adolescents
(GMFCS IV and V) with severe pelvic obliquity, but was also easily
detectable and clinically relevant in ambulant adolescents with mild
pelvic obliquity. The identification of pelvic obliquity and its management deserves
closer scrutiny in children and adolescents with cerebral palsy. Cite this article:
Several studies have reported the rate of post-operative
mortality after the surgical treatment of a fracture of the hip,
but few data are available regarding the delayed morbidity. In this
prospective study, we identified 568 patients who underwent surgery
for a fracture of the hip and who were followed for one year. Multivariate
analysis was carried out to identify possible predictors of mortality
and morbidity. The 30-day, four-month and one-year rates of mortality
were 4.3%, 11.4%, and 18.8%, respectively. General complications
and pre-operative comorbidities represented the basic predictors
of mortality at any time interval (p <
0.01). In-hospital, four-month
and one-year general complications occurred in 29.4%, 18.6% and
6.7% of patients, respectively. After adjusting for confounding variables,
comorbidities and poor cognitive status determined the likelihood
of early and delayed general complications, respectively (p <
0.001). Operative delay was the main predictor of the length of
hospital stay (p <
0.001) and was directly related to in-hospital
(p = 0.017) and four-month complications (p = 0.008). Cite this article:
If patients could recall their physical status
before total hip (THA) or knee arthroplasty (TKA) accurately it
could have valuable applications both clinically and for research.
This study evaluated the accuracy of a patient’s recollection one
year after either THA or TKA using the Oxford hip or knee scores
(OHS and OKS). In total, 113 patients (59 THA, 54 TKA) who had completed
the appropriate score pre-operatively were asked to complete the
score again at a mean of 12.4 months (standard deviation ( While there were no significant differences between the actual
and recalled pre-operative scores (OHS mean difference 0.8, A patient’s recollection of pre-operative pain and function is
inaccurate one year after THA or TKA. Cite this article:
Loosening of pedicle screws is a major complication of posterior
spinal stabilisation, especially in the osteoporotic spine. Our
aim was to evaluate the effect of cement augmentation compared with
extended dorsal instrumentation on the stability of posterior spinal
fixation. A total of 12 osteoporotic human cadaveric spines (T11-L3) were
randomised by bone mineral density into two groups and instrumented
with pedicle screws: group I (SHORT) separated T12 or L2 and group
II (EXTENDED) specimen consisting of T11/12 to L2/3. Screws were
augmented with cement unilaterally in each vertebra. Fatigue testing
was performed using a cranial-caudal sinusoidal, cyclic (1.0 Hz)
load with stepwise increasing peak force.Aims
Materials and 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
Modular junctions are ubiquitous in contemporary hip arthroplasty. The head-trunnion junction is implicated in the failure of large diameter metal-on-metal (MoM) hips which are the currently the topic of one the largest legal actions in the history of orthopaedics (estimated costs are stated to exceed $4 billion). Several factors are known to influence the strength of these press-fit modular connections. However, the influence of different head sizes has not previously been investigated. The aim of the study was to establish whether the choice of head size influences the initial strength of the trunnion-head connection. Ti-6Al-4V trunnions (n = 60) and two different sizes of cobalt-chromium (Co-Cr) heads (28 mm and 36 mm; 30 of each size) were used in the study. Three different levels of assembly force were considered: 4 kN; 5 kN; and 6 kN (n = 10 each). The strength of the press-fit connection was subsequently evaluated by measuring the pull-off force required to break the connection. The statistical differences in pull-off force were examined using a Kruskal–Wallis test and two-sample Mann–Whitney U test. Finite element and analytical models were developed to understand the reasons for the experimentally observed differences.Objectives
Materials and Methods
The aim of this study was to compare the operating
time, length of stay (LOS), adverse events and rate of re-admission
for elderly patients with a fracture of the hip treated using either
general or spinal anaesthesia. Patients aged ≥ 70 years who underwent
surgery for a fracture of the hip between 2010 and 2012 were identified
from the American College of Surgeons National Surgical Quality
Improvement Program (ACS-NSQIP) database. Of the 9842 patients who
met the inclusion criteria, 7253 (73.7%) were treated with general
anaesthesia and 2589 (26.3%) with spinal anaesthesia. On propensity-adjusted
multivariate analysis, general anaesthesia was associated with slightly increased
operating time (+5 minutes, 95% confidence interval (CI) +4 to +6,
p <
0.001) and post-operative time in the operating room (+5
minutes, 95% CI +2 to +8, p <
0.001) compared with spinal anaesthesia.
General anaesthesia was associated with a shorter LOS (hazard ratio
(HR) 1.28, 95% CI 1.22 to 1.34, p <
0.001). Any adverse event
(odds ratio (OR) 1.21, 95% CI 1.10 to 1.32, p <
0.001), thromboembolic
events (OR 1.90, 95% CI 1.24 to 2.89, p = 0.003), any minor adverse
event (OR 1.19, 95% CI 1.09 to 1.32, p <
0.001), and blood transfusion
(OR 1.34, 95% CI 1.22 to 1.49, p <
0.001) were associated with
general anaesthesia. General anaesthesia was associated with decreased
rates of urinary tract infection (OR 0.73, 95% CI 0.62 to 0.87,
p <
0.001). There was no clear overall advantage of one type
of anaesthesia over the other, and surgeons should be aware of the
specific risks and benefits associated with each type. Cite this article:
Whether to use total or unicompartmental knee
replacement (TKA/UKA) for end-stage knee osteoarthritis remains controversial.
Although UKA results in a faster recovery, lower rates of morbidity
and mortality and fewer complications, the long-term revision rate
is substantially higher than that for TKA. The effect of each intervention on
patient-reported outcome remains unclear. The aim of this study
was to determine whether six-month patient-reported outcome measures
(PROMs) are better in patients after TKA or UKA, using data from
a large national joint registry (NJR). We carried out a propensity score-matched cohort study which
compared six-month PROMs after TKA and UKA in patients enrolled
in the NJR for England and Wales, and the English national PROM
collection programme. A total of 3519 UKA patients were matched
to 10 557 TKAs. The mean six-month PROMs favoured UKA: the Oxford Knee Score
was 37.7 (95% confidence interval (CI) 37.4 to 38.0) for UKA and
36.1 (95% CI 35.9 to 36.3) for TKA; the mean EuroQol EQ-5D index
was 0.772 (95% CI 0.764 to 0.780) for UKA and 0.751 (95% CI 0.747
to 0.756) for TKA. UKA patients were more likely to achieve excellent
results (odds ratio (OR) 1.59, 95% CI 1.47 to 1.72, p <
0.001)
and to be highly satisfied (OR 1.27, 95% CI 1.17 to 1.39, p <
0.001), and
were less likely to report complications than those who had undergone
TKA. UKA gives better early patient-reported outcomes than TKA; these
differences are most marked for the very best outcomes. Complications
and readmission are more likely after TKA. Although the data presented
reflect the short-term outcome, they suggest that the high revision
rate for UKA may not be because of poorer clinical outcomes. These
factors should inform decision-making in patients eligible for either
procedure. Cite this article:
We wished to investigate the influence of metal debris exposure
on the subsequent immune response and resulting soft-tissue injury
following metal-on-metal (MoM) hip arthroplasty. Some reports have
suggested that debris generated from the head-neck taper junction
is more destructive than equivalent doses from metal bearing surfaces. We investigated the influence of the source and volume of metal
debris on chromium (Cr) and cobalt (Co) concentrations in corresponding
blood and hip synovial fluid samples and the observed agglomerated
particle sizes in excised tissues using multiple regression analysis
of prospectively collected data. A total of 199 explanted MoM hips
(177 patients; 132 hips female) were analysed to determine rates
of volumetric wear at the bearing surfaces and taper junctions. Aims
Patients and Methods
The primary aim of this study was to analyse the position of
the acetabular and femoral components in total hip arthroplasty
undertaken using an anterior surgical approach. In a prospective, single centre study, we used the EOS imaging
system to analyse the position of components following THA performed
via the anterior approach in 102 patients (103 hips) with a mean
age of 64.7 years (Aims
Patients and Methods
The December 2015 Research Roundup360 looks at: Biomarkers in periprosthetic joint infection; HbA1c and complications in arthroplasty; Getting to the bottom of biofilms; Effective antibiosis for biofilms; Stem cells and avascular necrosis; Predicting LOS in total joint arthroplasty; Long-term antibiotics reduce recurrence in periprosthetic infection
The December 2013 Knee Roundup360 looks at: Conflict of interest and hyaluronic acid; Will time indeed tell in microfracture?; Contralateral knee pain and joint replacement outcomes; Patient satisfaction and knee replacement?; Hope in the cytokines for painful TKRs?; Pain severity, cytokines and osteoarthritis?; Quadriceps weakness and pain; and spontaneous osteonecrosis of the knee
We determined the frequency, rate and extent
of development of scoliosis (coronal plane deformity) in wheelchair-dependent
patients with Duchenne muscular dystrophy (DMD) who were not receiving
steroid treatment. We also assessed kyphosis and lordosis (sagittal
plane deformity). The extent of scoliosis was assessed on sitting anteroposterior
(AP) spinal radiographs in 88 consecutive non-ambulatory patients
with DMD. Radiographs were studied from the time the patients became
wheelchair-dependent until the time of spinal fusion, or the latest assessment
if surgery was not undertaken. Progression was estimated using a
longitudinal mixed-model regression analysis to handle repeated
measurements. Scoliosis ≥ 10° occurred in 85 of 88 patients (97%), ≥ 20° in
78 of 88 (89%) and ≥ 30° in 66 of 88 patients (75%). The fitted
longitudinal model revealed that time in a wheelchair was a highly
significant predictor of the magnitude of the curve, independent
of the age of the patient (p <
0.001). Scoliosis developed in
virtually all DMD patients not receiving steroids once they became
wheelchair-dependent, and the degree of deformity deteriorated over
time. In general, scoliosis increased at a constant rate, beginning
at the time of wheelchair-dependency (p <
0.001). In some there
was no scoliosis for as long as three years after dependency, but
scoliosis then developed and increased at a constant rate. Some
patients showed a rapid increase in the rate of progression of the
curve after a few years – the clinical phenomenon of a rapidly collapsing
curve over a few months. A sagittal plane kyphotic deformity was seen in 37 of 60 patients
(62%) with appropriate radiographs, with 23 (38%) showing lumbar
lordosis (16 (27%) abnormal and seven (11%) normal). This study provides a baseline to assess the effects of steroids
and other forms of treatment on the natural history of scoliosis
in patients with DMD, and an approach to assessing spinal deformity
in the coronal and sagittal planes in wheelchair-dependent patients
with other neuromuscular disorders. Cite this article:
With greater numbers of younger patients undergoing
total hip replacement (THR), the effect of patient age on the diameter
of the femoral canal may become more relevant. This study aimed
to investigate the relationship between the diameter of the diaphysis
of the femoral canal with increasing age in a large number of patients
who underwent THR. A total of 1685 patients scheduled for THR had
their femoral dimensions recorded from calibrated radiographs. There
were 736 males and 949 females with mean ages of 67.1 years (34
to 92) and 70.2 years (29 to 92), respectively. The mean diameter
of the femoral canal was 13.3 mm (8.0 to 23.0) for males and 12.7
mm (6.0 to 26.0) for females. There was a poor correlation between
age and the diameter of the canal in males (r = 0.071, p = 0.05)
but a stronger correlation in females (r = 0.31, p <
0.001). The diameter of the femoral canal diameter of a female patient
undergoing THR could be predicted to increase by 3.2 mm between
the ages of 40 and 80 years, in contrast a male would be expected
to experience only a 0.6 mm increase during the same period. This
increase in the diameter of the canal with age might affect the
long-term survival of the femoral component in female patients. 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