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Stems improve the mechanical stability of tibial
components in total knee replacement (TKR), but come at a cost of stress
shielding along their length. Their advantages include resistance
to shear, reduced tibial lift-off and increased stability by reducing
micromotion. Longer stems may have disadvantages including stress
shielding along the length of the stem with associated reduction
in bone density and a theoretical risk of subsidence and loosening, peri-prosthetic
fracture and end-of-stem pain. These features make long stems unattractive
in the primary TKR setting, but often desirable in revision surgery
with bone loss and instability. In the revision scenario, stems
are beneficial in order to convey structural stability to the construct
and protect the reconstruction of bony defects. Cemented and uncemented
long stemmed implants have different roles depending on the nature
of the bone loss involved. This review discusses the biomechanics of the design of tibial
components and stems to inform the selection of the component and
the technique of implantation.
The current indications for functional restoration
of extension of the knee following quadriceps resection or loss require
reappraisal. The contribution of pedicled and free functional muscle
transfer is likely to be over-emphasised in many studies, with good
functional outcomes predominantly reported only in the context of
cases with residual quadriceps function. In cases with total quadriceps
resection or loss, all forms of reconstruction perform poorly. Furthermore,
in smaller resections with loss of two or fewer components of the
quadriceps, minimal impairment of function occurs in the absence
of functional reconstruction, suggesting that functional restoration
may not be warranted. Thus there is a paradox in the current approach
to quadriceps reconstruction, in that small resections are likely
to be over-treated and large resections remain under-treated. This review suggests a shift is required in the approach and
rationale for reconstructing functional extension of the knee after
quadriceps resection or loss. A classification based on current
evidence is suggested that emphasises more clearly the indications
and rationale for functional transfers.
The identification of the extent of neural damage
in patients with acute or chronic spinal cord injury is imperative for
the accurate prediction of neurological recovery. The changes in
signal intensity shown on routine MRI sequences are of limited value
for predicting functional outcome. Diffusion tensor imaging (DTI)
is a novel radiological imaging technique which has the potential
to identify intact nerve fibre tracts, and has been used to image
the brain for a variety of conditions. DTI imaging of the spinal
cord is currently only a research tool, but preliminary studies
have shown that it holds considerable promise in predicting the
severity of spinal cord injury. This paper briefly reviews our current knowledge of this technique.
The debate whether to use cemented or uncemented
components in primary total hip replacement (THR) has not yet been
considered with reference to the cost implications to the National
Health Service. We obtained the number of cemented and uncemented components
implanted in 2009 from the National Joint Registry for England and
Wales. The cost of each component was established. The initial financial
saving if all were cemented was then calculated. Subsequently the
five-year rates of revision for each type of component were reviewed
and the predicted number of revisions at five years for the actual
components used was compared with the predicted number of revisions
for a cemented THR. This was then multiplied by the mean cost of
revision surgery to provide an indication of the savings over the
first five years if all primary THRs were cemented. The saving at primary THR was calculated to be £10 million with
an additional saving during the first five years of between £5 million
and £8.5 million. The use of cemented components in routine primary
THR in the NHS as a whole can be justified on a financial level
but we recognise individual patient factors must be considered when deciding
which components to use.
It is accepted that resurfacing hip replacement
preserves the bone mineral density (BMD) of the femur better than total
hip replacement (THR). However, no studies have investigated any
possible difference on the acetabular side. Between April 2007 and March 2009, 39 patients were randomised
into two groups to receive either a resurfacing or a THR and were
followed for two years. One patient’s resurfacing subsequently failed,
leaving 19 patients in each group. Resurfaced replacements maintained proximal femoral BMD and,
compared with THR, had an increased bone mineral density in Gruen
zones 2, 3, 6, and particularly zone 7, with a gain of 7.5% (95%
confidence interval (CI) 2.6 to 12.5) compared with a loss of 14.6%
(95% CI 7.6 to 21.6). Resurfacing replacements maintained the BMD
of the medial femoral neck and increased that in the lateral zones
between 12.8% (95% CI 4.3 to 21.4) and 25.9% (95% CI 7.1 to 44.6). On the acetabular side, BMD was similar in every zone at each
point in time. The mean BMD of all acetabular regions in the resurfaced
group was reduced to 96.2% (95% CI 93.7 to 98.6) and for the total
hip replacement group to 97.6% (95% CI 93.7 to 101.5) (p = 0.4863).
A mean total loss of 3.7% (95% CI 1.0 to 6.5) and 4.9% (95% CI 0.8
to 9.0) of BMD was found above the acetabular component in W1 and
10.2% (95% CI 0.9 to 19.4) and 9.1% (95% CI 3.8 to 14.4) medial
to the implant in W2 for resurfaced replacements and THRs respectively.
Resurfacing resulted in a mean loss of BMD of 6.7% (95% CI 0.7 to
12.7) in W3 but the BMD inferior to the acetabular component was
maintained in both groups. These results suggest that the ability of a resurfacing hip replacement
to preserve BMD only applies to the femoral side.
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.
This prospective randomised controlled double-blind
trial compared two types of PFC Sigma total knee replacement (TKR),
differing in three design features aimed at improving flexion. The
outcome of a standard fixed-bearing posterior cruciate ligament-preserving
design (FB-S) was compared with that of a high-flexion rotating-platform
posterior-stabilised design (RP-F) at one year after TKR. The study group of 77 patients with osteoarthritis of the knee
comprised 37 men and 40 women, with a mean age of 69 years (44.9
to 84.9). The patients were randomly allocated either to the FB-S
or the RP-F group and assessed pre-operatively and at one year post-operatively.
The mean post-operative non-weight-bearing flexion was 107° (95%
confidence interval (CI) 104° to 110°)) for the FB-S group and 113°
(95% CI 109° to 117°) for the RP-F group, and this difference was
statistically significant (p = 0.032). However, weight-bearing range
of movement during both level walking and ascending a slope as measured
during flexible electrogoniometry was a mean of 4° lower in the RP-F
group than in the FB-S group, with 58° (95% CI 56° to 60°) Although the RP-F group achieved higher non-weight-bearing knee
flexion, patients in this group did not use this during activities
of daily living and reported more pain one year after surgery
Patient-reported outcome measures (PROMs) are
increasingly being used to assess functional outcome and patient satisfaction.
They provide a framework for comparisons between surgical units,
and individual surgeons for benchmarking and financial remuneration.
Better performance may bring the reward of more customers as patients and
commissioners seek out high performers for their elective procedures.
Using National Joint Registry (NJR) data linked to PROMs we identified
22 691 primary total knee replacements (TKRs) undertaken for osteoarthritis
in England and Wales between August 2008 and February 2011, and
identified the surgical factors that influenced the improvements
in the Oxford knee score (OKS) and EuroQol-5D (EQ-5D) assessment
using multiple regression analysis. After correction for patient
factors the only surgical factors that influenced PROMs were implant
brand and hospital type (both p <
0.001). However, the effects
of surgical factors upon the PROMs were modest compared with patient
factors. For both the OKS and the EQ-5D the most important factors
influencing the improvement in PROMs were the corresponding pre-operative
score and the patient’s general health status. Despite having only
a small effect on PROMs, this study has shown that both implant
brand and hospital type do influence reported subjective functional
scores following TKR. In the current climate of financial austerity,
proposed performance-based remuneration and wider patient choice,
it would seem unwise to ignore these effects and the influence of
a range of additional patient factors.
A consecutive series of patients with a hydroxyapatite-coated
uncemented total knee replacement (TKR) performed by a single surgeon
between 1992 and 1995 was analysed. All patients were invited for
clinical review and radiological assessment. Revision for aseptic
loosening was the primary outcome. Assessment was based on the Knee
Society clinical score (KSS) and an independent radiological analysis.
Of 471 TKRs performed in 356 patients, 432 TKRs in 325 patients
were followed for a mean of 16.4 years (15 to 18). The 39 TKRs in
31 patients lost to follow-up had a mean KSS of 176 (148 to 198)
at a mean of ten years. There were revisions in 26 TKRs (5.5%),
of which 11 (2.3%) were for aseptic loosening. Other further surgery
was carried out on 49 TKRs (10.4%) including patellar resurfacing
in 20, arthrolysis in 19, manipulation under anaesthetic in nine
and extensor mechanism reconstruction in one. Survivorship at up to 18 years without aseptic loosening was
96% (95% confidence interval 91.9 to 98.1), at which point the mean
KSS was 176 (134 to 200). Of 110 knees that underwent radiological
evaluation, osteolysis was observed in five (4.5%), one of which
was revised. These data indicate that uncemented hydroxyapatite-coated TKR
can achieve favourable long-term survivorship, at least as good
as that of cemented designs.
Medium-term survivorship of the Oxford phase
3 unicompartmental knee replacement (UKR) has not yet been established
in an Asian population. We prospectively evaluated the outcome of
400 phase 3 Oxford UKRs in 320 Korean patients with a mean age at
the time of operation of 69 years (48 to 82). The mean follow-up
was 5.2 years (1 to 10). Clinical and radiological assessment was
carried out pre- and post-operatively. At five years, the mean Knee
Society knee and functional scores had increased significantly from
56.2 (30 to 91) pre-operatively to 87.2 (59 to 98) (p = 0.034) and
from 59.2 (30 to 93) to 88.3 (50 to 100) (p = 0.021), respectively.
The Oxford knee score increased from a mean of 25.8 (12 to 39) pre-operatively
to 39.8 (25 to 58) at five years (p = 0.038). The ten-year survival
rate was 94% (95% confidence interval 90.1 to 98.0). A total of
14 UKRs (3.5%) required revision. The most common reason for revision
was dislocation of the bearing in 12 (3%). Conversion to a total
knee replacement was required in two patients who developed osteoarthritis
of the lateral compartment. This is the largest published series of UKR in Korean patients.
It shows that the mid-term results after a minimally invasive Oxford
phase 3 UKR can yield satisfactory clinical and functional results
in this group of patients.
Follow-up radiographs are usually used as the
reference standard for the diagnosis of suspected scaphoid fractures. However,
these are prone to errors in interpretation. We performed a meta-analysis
of 30 clinical studies on the diagnosis of suspected scaphoid fractures,
in which agreement data between any of follow-up radiographs, bone scintigraphy,
magnetic resonance (MR) imaging, or CT could be obtained, and combined
this with latent class analysis to infer the accuracy of these tests
on the diagnosis of suspected scaphoid fractures in the absence
of an established standard. The estimated sensitivity and specificity
were respectively 91.1% and 99.8% for follow-up radiographs, 97.8%
and 93.5% for bone scintigraphy, 97.7% and 99.8% for MRI, and 85.2%
and 99.5% for CT. The results were generally robust in multiple
sensitivity analyses. There was large between-study heterogeneity
for the sensitivity of follow-up radiographs and CT, and imprecision
about their sensitivity estimates. If we acknowledge the lack of a reference standard for diagnosing
suspected scaphoid fractures, MRI is the most accurate test; follow-up
radiographs and CT may be less sensitive, and bone scintigraphy
less specific.
A total of 92 patients with symptoms for over
six months due to subacromial impingement of the shoulder, who were
being treated with physiotherapy, were included in this study. While
continuing with physiotherapy they waited a further six months for
surgery. They were divided into three groups based on the following
four clinical and radiological criteria: temporary benefit following
steroid injection, pain in the mid-arc of abduction, a consistently positive
Hawkins test and radiological evidence of impingement. Group A fulfilled
all four criteria, group B three criteria and group C two criteria.
A total of nine patients improved while waiting for surgery and
were excluded, leaving 83 who underwent arthroscopic subacromial
decompression (SAD). The new Oxford shoulder score was recorded
pre-operatively and at three and 12 months post-operatively. A total of 51 patients (group A) had a significant improvement
in the mean shoulder score from 18 (13 to 22) pre-operatively to
38 (35 to 42) at three months (p <
0.001). The mean score in
this group was significantly better than in group B (21 patients)
and C (11 patients) at this time. At one year patients in all groups
showed improvement in scores, but patients in group A had a higher
mean score (p = 0.01). At one year patients in groups A and B did
better than those in group C (p = 0.01). Arthroscopic SAD is a beneficial intervention in selected patients.
The four criteria could help identify patients in whom it is likely
to be most effective.
Malunion is the most common complication of the
distal radius with many modalities of treatment available for such
a problem. The use of bone grafting after an osteotomy is still
recommended by most authors. We hypothesised that bone grafting
is not required; fixing the corrected construct with a volar locked
plate helps maintain the alignment, while metaphyseal defect fills
by itself. Prospectively, we performed the procedure on 30 malunited
dorsally-angulated radii using fixed angle volar locked plates without
bone grafting. At the final follow-up, 22 wrists were available.
Radiological evidence of union, correction of the deformity, clinical
and functional improvement was achieved in all cases. Without the
use of bone grafting, corrective open wedge osteotomy fixed by a
volar locked plate provides a high rate of union and satisfactory
functional outcomes.
The aim of this study was first, to determine
whether CT scans undertaken to identify serious injury to the viscera were
of use in detecting clinically unrecognised fractures of the thoracolumbar
vertebrae, and second, to identify patients at risk of ‘missed injury’. We retrospectively analysed CT scans of the chest and abdomen
performed for blunt injury to the torso in 303 patients. These proved
to be positive for thoracic and intra-abdominal injuries in only
2% and 1.3% of cases, respectively. However, 51 (16.8%) showed a
fracture of the thoracolumbar vertebrae and these constituted our subset
for study. There were eight women and 43 men with mean age of 45.2
years (15 to 94). There were 29 (57%) stable and 22 (43%) unstable
fractures. Only 17 fractures (33.3%) had been anticipated after
clinical examination. Of the 22 unstable fractures, 11 (50%) were
anticipated. Thus, within the whole group of 303 patients, an unstable spinal
injury was missed in 11 patients (3.6%); no harm resulted as they
were all protected until the spine had been cleared. A subset analysis
revealed that patients with a high Injury Severity Score, a low
Glasgow Coma Scale and haemodynamic instability were most likely
to have a significant fracture in the absence of positive clinical
findings. This is the group at greatest risk. Clinical examination alone cannot detect significant fractures
of the thoracolumbar spine. It should be combined with CT imaging
to reduce the risk of missed injury.
The purpose of this study was to determine whether
patients with a burst fracture of the thoracolumbar spine treated
by short segment pedicle screw fixation fared better clinically
and radiologically if the affected segment was fused at the same
time. A total of 50 patients were enrolled in a prospective study
and assigned to one of two groups. After the exclusion of three
patients, there were 23 patients in the fusion group and 24 in the
non-fusion group. Follow-up was at a mean of 23.9 months (18 to
30). Functional outcome was evaluated using the Greenough Low Back
Outcome Score. Neurological function was graded using the American
Spinal Injury Association Impairment Scale. Peri-operative blood transfusion requirements and duration of
surgery were significantly higher in the fusion group (p = 0.029
and p <
0.001, respectively). There were no clinical or radiological
differences in outcome between the groups (all outcomes p >
0.05).
The results of this study suggest that adjunctive fusion is unnecessary
when managing patients with a burst fracture of the thoracolumbar
spine with short segment pedicle screw fixation.
Techniques for fixation of fractures of the lateral
malleolus have remained essentially unchanged since the 1960s, but
are associated with complication rates of up to 30%. The fibular
nail is an alternative method of fixation requiring a minimal incision
and tissue dissection, and has the potential to reduce the incidence
of complications. We reviewed the results of 105 patients with unstable fractures
of the ankle that were fixed between 2002 and 2010 using the Acumed
fibular nail. The mean age of the patients was 64.8 years (22 to
95), and 80 (76%) had significant systemic medical comorbidities.
Various different configurations of locking screw were assessed
over the study period as experience was gained with the device.
Nailing without the use of locking screws gave satisfactory stability
in only 66% of cases (4 of 6). Initial locking screw constructs
rendered between 91% (10 of 11) and 96% (23 of 24) of ankles stable.
Overall, seven patients had loss of fixation of the fracture and
there were five post-operative wound infections related to the distal
fibula. This lead to the development of the current technique with
a screw across the syndesmosis in addition to a distal locking screw.
In 21 patients treated with this technique there have been no significant
complications and only one superficial wound infection. Good fracture
reduction was achieved in all of these patients. The mean physical
component Short-Form 12, Olerud and Molander score, and American Academy
of Orthopaedic Surgeons Foot and Ankle outcome scores at a mean
of six years post-injury were 46 (28 to 61), 65 (35 to 100) and
83 (52 to 99), respectively. There have been no cases of fibular
nonunion. Nailing of the fibula using our current technique gives good
radiological and functional outcomes with minimal complications,
and should be considered in the management of patients with an unstable
ankle fracture.
Using data from the Norwegian Hip Fracture Register,
8639 cemented and 2477 uncemented primary hemiarthroplasties for
displaced fractures of the femoral neck in patients aged > 70 years
were included in a prospective observational study. A total of 218
re-operations were performed after cemented and 128 after uncemented
procedures. Survival of the hemiarthroplasties was calculated using
the Kaplan-Meier method and hazard rate ratios (HRR) for revision
were calculated using Cox regression analyses. At five years the
implant survival was 97% (95% confidence interval (CI) 97 to 97)
for cemented and 91% (95% CI 87 to 94) for uncemented hemiarthroplasties.
Uncemented hemiarthroplasties had a 2.1 times increased risk of
revision compared with cemented prostheses (95% confidence interval
1.7 to 2.6, p < 0.001). The increased risk was mainly caused
by revisions for peri-prosthetic fracture (HRR = 17), aseptic loosening
(HRR = 17), haematoma formation (HRR = 5.3), superficial infection
(HRR = 4.6) and dislocation (HRR = 1.8). More intra-operative complications,
including intra-operative death, were reported for the cemented
hemiarthroplasties. However, in a time-dependent analysis, the HRR
for re-operation in both groups increased as follow-up increased. This study showed that the risk for revision was higher for uncemented
than for cemented hemiarthroplasties.
Using general practitioner records and hospital
notes and through direct telephone conversation with patients, we investigated
the accuracy of nine patient-reported complications gathered from
a self-completed questionnaire after elective joint replacement
surgery of the hip and knee. A total of 402 post-discharge complications
were reported after 8546 elective operations that were undertaken
within a three-year period. These were reported by 136 men and 240
women with a mean age of 71.8 years (34 to 93). A total of 319 reported
complications (79.4%; 95% confidence interval 75.4 to 83.3) were
confirmed to be correct. High rates of correct reporting were demonstrated
for infection (94.5%) and the need for further surgery (100%), whereas
the rates of reporting deep-vein thrombosis (DVT), pulmonary embolism,
myocardial infarction and stroke were lower (75% to 84.2%). Dislocation,
peri-prosthetic fractures and nerve palsy had modest rates of correct
reporting (36% to 57.1%). More patients who had knee surgery delivered
incorrect reports of dislocation (p = 0.001) and DVT (p = 0.013). Despite these variations, it appears that post-operative complications
may form part of a larger patient-reported outcome programme after
elective joint replacement surgery.
We report a systematic review and meta-analysis
of the peer-reviewed literature focusing on metal sensitivity testing
in patients undergoing total joint replacement (TJR). Our purpose
was to assess the risk of developing metal hypersensitivity post-operatively
and its relationship with outcome and to investigate the advantages
of performing hypersensitivity testing. We undertook a comprehensive search of the citations quoted in
PubMed and EMBASE: 22 articles (comprising 3634 patients) met the
inclusion criteria. The frequency of positive tests increased after
TJR, especially in patients with implant failure or a metal-on-metal
coupling. The probability of developing a metal allergy was higher
post-operatively (odds ratio (OR) 1.52 (95% confidence interval
(CI) 1.06 to 2.31)), and the risk was further increased when failed
implants were compared with stable TJRs (OR 2.76 (95% CI 1.14 to
6.70)). Hypersensitivity testing was not able to discriminate between
stable and failed TJRs, as its predictive value was not statistically
proven. However, it is generally thought that hypersensitivity testing
should be performed in patients with a history of metal allergy
and in failed TJRs, especially with metal-on-metal implants and
when the cause of the loosening is doubtful.
Previously, we showed that case-specific non-linear
finite element (FE) models are better at predicting the load to failure
of metastatic femora than experienced clinicians. In this study
we improved our FE modelling and increased the number of femora
and characteristics of the lesions. We retested the robustness of
the FE predictions and assessed why clinicians have difficulty in
estimating the load to failure of metastatic femora. A total of
20 femora with and without artificial metastases were mechanically
loaded until failure. These experiments were simulated using case-specific
FE models. Six clinicians ranked the femora on load to failure and
reported their ranking strategies. The experimental load to failure
for intact and metastatic femora was well predicted by the FE models (R2 =
0.90 and R2 = 0.93, respectively). Ranking metastatic
femora on load to failure was well performed by the FE models (τ =
0.87), but not by the clinicians (0.11 <
τ <
0.42). Both the
FE models and the clinicians allowed for the characteristics of
the lesions, but only the FE models incorporated the initial bone
strength, which is essential for accurately predicting the risk
of fracture. Accurate prediction of the risk of fracture should
be made possible for clinicians by further developing FE models.
Although equinus gait is the most common abnormality
in children with spastic cerebral palsy (CP) there is no consistency
in recommendations for treatment, and evidence for best practice
is lacking. The Baumann procedure allows selective fractional lengthening
of the gastrocnemii and soleus muscles but the long-term outcome
is not known. We followed a group of 18 children (21 limbs) with
diplegic CP for ten years using three-dimensional instrumented gait
analysis. The kinematic parameters of the ankle joint improved significantly
following this procedure and were maintained until the end of follow-up.
We observed a normalisation of the timing of the key kinematic and
kinetic parameters, and an increase in the maximum generation of
power of the ankle. There was a low rate of overcorrection (9.5%,
n = 2), and a rate of recurrent equinus similar to that found with
other techniques (23.8%, n = 5). As the procedure does not impair the muscle architecture, and
allows for selective correction of the contracted gastrocnemii and
soleus, it may be recommended as the preferred method for correction
of a mild fixed equinus deformity.
Although good to excellent short-term results
of arthroscopic partial limbectomy of the hip have been reported, there
is little information on the long-term outcome of the procedure.
We report a case with a 16-year follow-up. A 34-year old woman presented with a three-month history of severe
pain and limitation of movement of the hip. Plain radiographs and
arthrography showed no abnormality. MRI showed an effusion and a
deformity of the anterosuperior part of the labrum. This was confirmed
as an inverted labral tear that was debrided arthroscopically. At 16 years post-operatively, she remained symptom-free. Plain
radiographs showed no abnormality and MRI suggested that the sealing
effect of the scar tissue prevented articular damage and degeneration.
The FRCS (Tr &
Orth) examination has three components: MCQs, Vivas and Clinical Examination. The Vivas are further divided into four sections comprising Basic Science, Adult Pathology, Hands and Children’s Orthopaedics and Trauma. The Clinical Examination section is divided into Upper and Lower limb cases. The aim of this section in the Journal is to focus specifically on the trainees preparing for the exam and to cater to all the sections of the exam. The vision is to complete the cycle of all relevant exam topics (as per the syllabus) in four years.