The β-angle is a radiological tool for measuring the distance between the pathological head-neck junction and the acetabular rim with the hip in 90° of flexion in patients with femoroacetabular impingement. Initially it was measured using an open-chamber MRI. We have developed a technique to measure this angle on plain radiographs. Correlation analysis was undertaken to determine the relationship between the range of movement and the β-angle in 50 patients with femoroacetabular impingement and 50 asymptomatic control subjects. Inter- and intra-observer reliability of the β-angle was also evaluated. Patients with femoroacetabular impingement had a significantly smaller (p <
0.001) mean β-angle (15.6°, 95% confidence interval (CI) 13.3 to 17.7) compared with the asymptomatic group (38.7°, 95% CI 36.5 to 41.0). Correlation between internal rotation and the β-angle was high in the impingement group and moderate in the asymptomatic group. The β-angle had excellent inter- and intra-observer reliability in both groups. Our findings suggest that the measurement of the β-angle on plain radiography may represent a valid, reproducible and cost-effective alternative to open MRI in the assessment of the pathological bony anatomy in patients with cam, pincer and mixed femoroacetabular impingement.
Deformity after slipped upper femoral epiphysis
(SUFE) can cause cam-type femoroacetabular impingement (FAI) and
subsequent osteoarthritis (OA). However, there is little information
regarding the radiological assessment and clinical consequences
at long-term follow-up. We reviewed 36 patients (43 hips) previously
treated by We conclude that persistent deformity with radiological cam FAI
after SUFE is associated with poorer clinical and radiological long-term
outcome. Although the radiological measurements had quite wide limits
of agreement, they are useful for the diagnosis of post-slip deformities
in clinical practice.
In a double-blinded randomised controlled trial,
83 patients with primary osteoarthritis of the hip received either
a ceramic-on-metal (CoM) or metal-on-metal (MoM) total hip replacement
(THR). The implants differed only in the bearing surfaces used.
The serum levels of cobalt and chromium and functional outcome scores
were compared pre-operatively and at six and 12 months post-operatively. Data were available for 41 CoM and 36 MoM THRs (four patients
were lost to follow-up, two received incorrect implants). The baseline
characteristics of both cohorts were similar. Femoral head size
measured 36 mm in all but two patients who had 28 mm heads. The
mean serum cobalt and chromium levels increased in both groups,
with no difference noted between groups at six months (cobalt p
= 0.67, chromium p = 0.87) and 12 months (cobalt p = 0.76, chromium
p = 0.76) post-operatively. Similarly, the mean Oxford hip scores,
Western Ontario and McMaster Universities Osteoarthritis index and
University of California, Los Angeles activity scores showed comparable improvement
at 12 months. Our findings indicate that CoM and MoM couplings are associated
with an equivalent increase in serum cobalt and chromium levels,
and comparable functional outcome scores at six and 12-months follow-up.
Plasma levels of cobalt and chromium ions and
Metal Artefact Reduction Sequence (MARS)-MRI scans were performed
on patients with 209 consecutive, unilateral, symptomatic metal-on-metal
(MoM) hip arthroplasties. There was wide variation in plasma cobalt
and chromium levels, and MARS-MRI scans were positive for adverse reaction
to metal debris (ARMD) in 84 hips (40%). There was a significant
difference in the median plasma cobalt and chromium levels between
those with positive and negative MARS-MRI scans (p <
0.001).
Compared with MARS-MRI as the potential reference standard for the
diagnosis of ARMD, the sensitivity of metal ion analysis for cobalt
or chromium with a cut-off of >
7 µg/l was 57%. The specificity was
65%, positive predictive value was 52% and the negative predictive
value was 69% in symptomatic patients. A lowered threshold of >
3.5 µg/l for cobalt and chromium ion levels improved the sensitivity
and negative predictive value to 86% and 74% but at the expense
of specificity (27%) and positive predictive value (44%). Metal ion analysis is not recommended as a sole indirect screening
test in the surveillance of symptomatic patients with a MoM arthroplasty.
The investigating clinicians should have a low threshold for obtaining
cross-sectional imaging in these patients, even in the presence
of low plasma metal ion levels.
Our aim was to compare the one-year post-operative
outcomes following retention or removal of syndesmotic screws in
adult patients with a fracture of the ankle that was treated surgically.
A total of 51 patients (35 males, 16 females), with a mean age of
33.5 years (16 to 62), undergoing fibular osteosynthesis and syndesmotic
screw fixation, were randomly allocated to retention of the syndesmotic
screw or removal at three months post-operatively. The two groups
were comparable at baseline. One year post-operatively, there was no significant difference
in the mean Olerud–Molander ankle score (82.4 retention We conclude that removal of a syndesmotic screw produces no significant
functional, clinical or radiological benefit in adult patients who
are treated surgically for a fracture of the ankle. Cite this article:
We evaluated the concentrations of chromium and cobalt ions in blood after metal-on-metal surface replacement arthroplasty using a wrought-forged, high carbon content chromium-cobalt alloy implant in 64 patients. At one year, mean whole blood ion levels were 1.61 μg/L (0.4 to 5.5) for chromium and 0.67 μg/L (0.23 to 2.09) for cobalt. The pre-operative ion levels, component size, female gender and the inclination of the acetabular component were inversely proportional to the values of chromium and/or cobalt ions at one year postoperatively. Other factors, such as age and level of activity, did not correlate with the levels of metal ions. We found that the levels of the ions in the serum were 1.39 and 1.37 times higher for chromium and cobalt respectively than those in the whole blood. The levels of metal ions obtained may be specific to the hip resurfacing implant and reflect its manufacturing process.
This study used CT analysis to determine the rotational alignment of 39 painful and 26 painless fixed-bearing total knee replacements (TKRs) from a cohort of 740 NexGen Legacy posterior-stabilised and cruciate-retaining prostheses implanted between May 1996 and August 2003. The mean rotation of the tibial component was 4.3° of internal rotation (25.4° internal to 13.9° external rotation) in the painful group and 2.2° of external rotation (8.5° internal to 18.2° external rotation) in the painfree group (p = 0.024). In the painful group 17 tibial components were internally rotated more than 9° compared with none in the painfree group (p <
0.001). Additionally, six femoral components in the painful group were internally rotated more than 6° compared with none in the painfree group (p = 0.017). External rotational errors were not found to be associated with pain. Overall, 22 (56.4%) of the painful TKRs had internal rotational errors involving the femoral, the tibial or both components. It is estimated that at least 4.6% of all our TKRs have been implanted with significant internal rotational errors.
We developed the Oxford ankle foot questionnaire to assess the disability associated with foot and ankle problems in children aged from five to 16 years. A survey of 158 children and their parents was carried out to determine the content, scaling, reliability and validity of the instrument. Scores from the questionnaire can be calculated to measure the effect of foot or ankle problems on three domains of children’s lives: physical, school and play, and emotional. Scores for each domain were shown to be internally consistent, stable, and to vary little whether reported by child or parent. Satisfactory face, content and construct validity were demonstrated. The questionnaire is appropriate for children with a range of conditions and can provide clinically useful information to supplement other assessment methods. We are currently carrying out further work to assess the responsiveness of questionnaire scores to change over time and with treatment.
The purpose of this study was to assess N-acetyl aspartate changes
in the thalamus in patients with osteoarthritis of the hip using
proton magnetic resonance spectroscopy. Nine patients with osteoarthritis of the hip (symptomatic group,
nine women; mean age 61.4 years (48 to 78)) and nine healthy volunteers
(control group, six men, three women; mean age 30.0 years (26 to
38)) underwent proton magnetic resonance spectroscopy to assess
the changes of N-acetyl aspartate in the thalamus. Objectives
Methods
We obtained pre-operative and six-month post-operative
Oxford hip (OHS) and knee scores (OKS) for 1523 patients who underwent
total hip replacement and 1784 patients who underwent total knee
replacement. They all also completed a six-month satisfaction question. Scatter plots showed no relationship between pre-operative Oxford
scores and six-month satisfaction scores. Spearman’s rank correlation
coefficients were -0.04 (95% confidence interval (CI) -0.09 to 0.01)
between OHS and satisfaction and 0.04 (95% CI -0.01 to 0.08) between
OKS and satisfaction. A receiver operating characteristic (ROC) curve
analysis was used to identify a cut-off point for the pre-operative
OHS/OKS that identifies whether or not a patient is satisfied with
surgery. We obtained an area under the ROC curve of 0.51 (95% CI
0.45 to 0.56) for hip replacement and 0.56 (95% CI 0.51 to 0.60)
for knee replacement, indicating that pre-operative Oxford scores
have no predictive accuracy in distinguishing satisfied from dissatisfied
patients. In the NHS widespread attempts are being made to use patient-reported
outcome measures (PROMs) data for the purpose of prioritising patients
for surgery. Oxford hip and knee scores have no predictive accuracy
in relation to post-operative patient satisfaction. This evidence
does not support their current use in prioritising access to care.
There is a high rate of mortality in elderly
patients who sustain a fracture of the hip. We aimed to determine
the rate of preventable mortality and errors during the management
of these patients. A 12 month prospective study was performed on
patients aged >
65 years who had sustained a fracture of the hip.
This was conducted at a Level 1 Trauma Centre with no orthogeriatric
service. A multidisciplinary review of the medical records by four
specialists was performed to analyse errors of management and elements
of preventable mortality. During 2011, there were 437 patients aged
>
65 years admitted with a fracture of the hip (85 years (66 to
99)) and 20 died while in hospital (86.3 years (67 to 96)). A total
of 152 errors were identified in the 80 individual reviews of the
20 deaths. A total of 99 errors (65%) were thought to have at least
a moderate effect on death; 45 reviews considering death (57%) were thought
to have potentially been preventable. Agreement between the panel
of reviewers on the preventability of death was fair. A larger-scale
assessment of preventable mortality in elderly patients who sustain
a fracture of the hip is required. Multidisciplinary review panels
could be considered as part of the quality assurance process in
the management of these patients. Cite this article
We conducted a retrospective study to assess
the prevalence of adverse reactions to metal debris (ARMD) in patients
operated on at our institution with metal-on-metal (MoM) total hip
replacements with 36 mm heads using a Pinnacle acetabular shell.
A total of 326 patients (150 males, 175 hips; 176 females, 203 hips)
with a mean age of 62.7 years (28 to 85) and mean follow-up of 7.5
years (0.1 to 10.8) participating in our in-depth modern MoM follow-up
programme were included in the study, which involved recording whole
blood cobalt and chromium ion measurements, Oxford hip scores (OHS)
and plain radiographs of the hip and targeted cross-sectional imaging. Elevated
blood metal ion levels (>
5 parts per billion) were seen in 32 (16.1%)
of the 199 patients who underwent unilateral replacement. At 23
months after the start of our modern MoM follow-up programme, 29
new cases of ARMD had been revealed. Hence, the nine-year survival
of this cohort declined from 96% (95% CI 95 to 98) with the old
surveillance routine to 86% (95% CI 82 to 90) following the new
protocol. Although ARMD may not be as common in 36 mm MoM THRs as
in those with larger heads, these results support the Medicines
and Healthcare Products Regulatory Agency guidelines on regular
reviews and further investigations, and emphasise the need for specific
a follow-up programme for patients with MoM THRs. Cite this article:
The relationship between post-operative bone
density and subsequent failure of total knee replacement (TKR) is
not known. This retrospective study aimed to determine the relationship
between bone density and failure, both overall and according to
failure mechanism. All 54 aseptic failures occurring in 50 patients
from 7760 consecutive primary cemented TKRs between 1983 and 2004
were matched with non-failing TKRs, and 47 failures in 44 patients
involved tibial failures with the matching characteristics of age
(65.1 for failed and 69.8 for non-failed), gender (70.2% female), diagnosis
(93.6% OA), date of operation, bilaterality, pre-operative alignment
(0.4 and 0.3 respectively), and body mass index (30.2 and 30.0 respectively).
In each case, the density of bone beneath the tibial component was assessed
at each follow-up interval using standardised, calibrated radiographs.
Failing knees were compared with controls both overall and, as a
subgroup analysis, by failure mechanism. Knees were compared with
controls using univariable linear regression. Significant and continuous elevation in tibial density was found
in knees that eventually failed by medial collapse (p <
0.001)
and progressive radiolucency (p <
0.001) compared with controls,
particularly in the medial region of the tibia. Knees failing due
to ligamentous instability demonstrated an initial decline in density
(p = 0.0152) followed by a non-decreasing density over time (p =
0.034 for equivalence). Non-failing knees reported a decline in
density similar to that reported previously using dual-energy x-ray
absorptiometry (DEXA). Differences between failing and non-failing
knees were observable as early as two months following surgery.
This tool may be used to identify patients at risk of failure following
TKR, but more validation work is needed. Cite this article:
The June 2014 Children’s orthopaedics Roundup360 looks at: plaster wedging in paediatric forearm fractures; the medial approach for DDH; Ponseti – but not as he knew it?; Salter osteotomy more accurate than Pemberton in DDH; is the open paediatric fracture an emergency?; bang up-to-date with femoral external fixation; indomethacin, heterotopic ossification and cerebral palsy hips; lengthening nails for congenital femoral deformities, and is MRI the answer to imaging of the physis?
We evaluated the incidence of heterotopic ossification
following total ankle replacement to determine whether the degree
of ossification was associated with the clinical outcome. We evaluated
90 ankles in 81 consecutive patients who underwent total ankle replacement,
and heterotopic ossification was assessed according to proportional involvement
of the ankle joint. Correlation analysis was used to investigate
the association between heterotopic ossification and outcome. No significant association was found between the formation of
heterotopic ossification and the clinical outcome. The degree of
heterotopic ossification in the posterior ankle joint was not significantly
correlated with posterior ankle pain (p = 0.929), the American Orthopaedic
Foot and Ankle Society score (p = 0.454) or range of movement (p
= 0.283). This study indicates that caution should be observed in attributing
symptoms and functional limitation to the presence of heterotopic
ossification in the posterior ankle joint when considering excision
of heterotopic bone after total ankle replacement.
The computed neck-shaft angle and the size of the femoral component were recorded in 100 consecutive hip resurfacings using imageless computer-navigation and compared with the angle measured before operation and with actual component implanted. The reliability of the registration was further analysed using ten cadaver femora. The mean absolute difference between the measured and navigated neck-shaft angle was 16.3° (0° to 52°). Navigation underestimated the measured neck-shaft angle in 38 patients and the correct implant size in 11. Registration of the cadaver femora tended to overestimate the correct implant size and provided a low level of repeatability in computing the neck-shaft angle. Prudent pre-operative planning is advisable for use in conjunction with imageless navigation since misleading information may be registered intraoperatively, which could lead to inappropriate sizing and positioning of the femoral component in hip resurfacing.
In 1937 Blount described a series of 28 patients with ‘Tibia vara’. Since then, a number of deformities in the tibia and the femur have been described in association with this condition. We analysed 14 children with Blount’s disease who were entered into a cross-sectional study. Their mean age was 10 (2 to 18). They underwent a clinical assessment of the rotational profile of their legs and a CT assessment of the angle of anteversion of their hips (femoral version). We compared our results to previously published controls. A statistically significant increase in femoral anteversion was noted in the affected legs, with on average the femurs in patients with Blount’s disease being 26° more anteverted than those in previously published controls. We believe this to be a previously unrecognised component of Blount’s disease, and that the marked intoeing seen in the disease may be partly caused by internal femoral version, in addition to the well-recognised internal tibial version.
The three-dimensional (3D) correction of glenoid
erosion is critical to the long-term success of total shoulder replacement
(TSR). In order to characterise the 3D morphology of eroded glenoid
surfaces, we looked for a set of morphological parameters useful
for TSR planning. We defined a scapular coordinates system based
on non-eroded bony landmarks. The maximum glenoid version was measured
and specified in 3D by its orientation angle. Medialisation was
considered relative to the spino-glenoid notch. We analysed regular
CT scans of 19 normal (N) and 86 osteoarthritic (OA) scapulae. When
the maximum version of OA shoulders was higher than 10°, the orientation
was not only posterior, but extended in postero-superior (35%),
postero-inferior (6%) and anterior sectors (4%). The medialisation
of the glenoid was higher in OA than normal shoulders. The orientation
angle of maximum version appeared as a critical parameter to specify
the glenoid shape in 3D. It will be very useful in planning the
best position for the glenoid in TSR. Cite this article:
The responsiveness of the Manchester–Oxford Foot
Questionnaire (MOXFQ) was compared with foot/ankle-specific and
generic outcome measures used to assess all surgery of the foot
and ankle. We recruited 671 consecutive adult patients awaiting
foot or ankle surgery, of whom 427 (63.6%) were female, with a mean
age of 52.8 years (18 to 89). They independently completed the MOXFQ,
Short-Form 36 (SF-36) and EuroQol (EQ-5D) questionnaires pre-operatively
and at a mean of nine months (3.8 to 14.4) post-operatively. Foot/ankle
surgeons assessed American Orthopaedic Foot and Ankle Society (AOFAS)
scores corresponding to four foot/ankle regions. A transition item measured
perceived changes in foot/ankle problems post-surgery. Of 628 eligible
patients proceeding to surgery, 491 (78%) completed questionnaires
and 262 (42%) received clinical assessments both pre- and post-operatively. The
regions receiving surgery were: multiple/whole foot in eight (1.3%),
ankle/hindfoot in 292 (46.5%), mid-foot in 21 (3.3%), hallux in
196 (31.2%), and lesser toes in 111 (17.7%). Foot/ankle-specific
MOXFQ, AOFAS and EQ-5D domains produced larger effect sizes (>
0.8)
than any SF-36 domains, suggesting superior responsiveness. In analyses
that anchored change in scores and effect sizes to patients’ responses
to a transition item about their foot/ankle problems, the MOXFQ
performed well. The SF-36 and EQ-5D performed poorly. Similar analyses,
conducted within foot-region based sub-groups of patients, found
that the responsiveness of the MOXFQ was good compared with the
AOFAS. This evidence supports the MOXFQ’s suitability for assessing
all foot and ankle surgery.
Fractures of the tibial shaft are common injuries,
but there are no long-term outcome data in the era of increased surgical
management. The aim of this prospective study was to assess the
clinical and functional outcome of this injury at 12 to 22 years.
Secondary aims were to determine the short- and long-term mortality,
and if there were any predictors of clinical or functional outcome
or mortality. From a prospective trauma database of 1502 tibial
shaft fractures in 1474 consecutive adult patients, we identified
a cohort of 1431 tibial diaphyseal fractures in 1403 patients, who
fitted our inclusion criteria. There were 1024 men, and mean age
at injury was 40.6 years. Fractures were classified according to
the AO system, and open fractures graded after Gustilo and Anderson.
Requirement of fasciotomy, time to fracture union, complications,
incidence of knee and ankle pain at long-term follow-up, changes in
employment and the patients’ social deprivation status were recorded.
Function was assessed at 12 to 22 years post-injury using the Short
Musculoskeletal Function Assessment and short form-12 questionnaires.
Long-term functional outcome data was available for 568 of the surviving
patients, 389 were deceased and 346 were lost to follow-up. Most
fractures (90.7%, n = 1363) united without further intervention.
Fasciotomies were performed in 11.5% of patients; this did not correlate
with poorer functional outcome in the long term. Social deprivation
was associated with a higher incidence of injury but had no impact
on long-term function. The one-year mortality in those over 75 years
of age was 29 (42%). At long-term follow-up, pain and function scores
were good. However, 147 (26%) reported ongoing knee pain, 62 (10%)
reported ankle pain and 97 (17%) reported both. Such joint pain correlated
with poorer functional outcome. Cite this article: