Massive endoprostheses rely on extra-cortical bone bridging (ECBB)
to enhance fixation. The aim of this study was to investigate the
role of selective laser sintered (SLS) porous collars in augmenting
the osseointegration of these prostheses. The two novel designs of porous SLS collars, one with small pores
(Ø700 μm, SP) and one with large pores (Ø1500 μm, LP), were compared
in an ovine tibial diaphyseal model. Osseointegration of these collars
was compared with that of a clinically used solid, grooved design
(G). At six months post-operatively, the ovine tibias were retrieved and
underwent radiological and histological analysis.Aims
Materials and Methods
Increasing innovation in rapid prototyping (RP)
and additive manufacturing (AM), also known as 3D printing, is bringing
about major changes in translational surgical research. This review describes the current position in the use of additive
manufacturing in orthopaedic surgery. Cite this article:
We report on the outcome of the Synergy cementless femoral stem
with a minimum follow-up of 15 years (15 to 17). A retrospective review was undertaken of a consecutive series
of 112 routine primary cementless total hip arthroplasties (THAs)
in 102 patients (112 hips). There were 60 female and 42 male patients
with a mean age of 61 years (18 to 82) at the time of surgery. A
total of 78 hips in the 69 patients remain Aims
Patients and Methods
Patients with neuromuscular imbalance who require
total hip arthroplasty (THA) present particular technical problems
due to altered anatomy, abnormal bone stock, muscular imbalance
and problems of rehabilitation. In this systematic review, we studied articles dealing with THA
in patients with neuromuscular imbalance, published before April
2017. We recorded the demographics of the patients and the type
of neuromuscular pathology, the indication for surgery, surgical
approach, concomitant soft-tissue releases, the type of implant
and bearing, pain and functional outcome as well as complications
and survival. Recent advances in THA technology allow for successful outcomes
in these patients. Our review suggests excellent benefits for pain
relief and good functional outcome might be expected with a modest
risk of complication. Cite this article:
The inherent challenges of total hip replacement
(THR) in children include the choice of implant for the often atypical
anatomical morphology, its fixation to an immature growing skeleton
and the bearing surface employed to achieve a successful long-term
result. We report the medium-term results of 52 consecutive uncemented
THRs undertaken in
35 paediatric patients with juvenile idiopathic arthritis. The mean
age at the time of surgery was 14.4 years (10 to 16). The median
follow-up was 10.5 years (6 to 15). During the study period 13 THRs
underwent revision surgery. With revision as an endpoint, subgroup
analysis revealed 100% survival of the 23 ceramic-on-ceramic THRs
and 55% (16 of 29) of the metal- or ceramic-on-polyethylene. This
resulted in 94% (95% CI 77.8 to 98.4) survivorship of the femoral
component and 62% (95% CI 41.0 to 78.0) of the acetabular component.
Revision of the acetabular component for wear and osteolysis were
the most common reasons for failure accounting for 11 of the 13
revisions. The success seen in patients with a ceramic-on-ceramic articulation
seems to indicate that this implant strategy has the potential to
make a major difference to the long-term outcome in this difficult
group of patients.
The primary aim of this independent prospective randomised trial
was to compare serum metal ion levels for ceramic-on-metal (CoM)
and metal-on-metal (MoM) bearing surfaces in total hip arthroplasty
(THA). Our one-year results demonstrated elevation in metal ion
levels above baseline with no significant difference between the
CoM and MoM groups. This paper reviews the five-year data. The implants used in each patient differed only in respect to
the type of femoral head (ceramic or metal). At five-year follow-up
of the 83 enrolled patients, data from 67 (36 CoM, 31 MoM) was available
for comparison.Aims
Patients and Methods
We report the clinical and radiological outcomes
of a series of contemporary cementless ceramic-on-ceramic total hip
replacements (THRs) at ten years in patients aged ≤ 55 years of
age. Pre- and post-operative activity levels are described. A total
of 120 consecutive ceramic cementless THRs were performed at a single
centre in 110 patients from 1997 to 1999. The mean age of the patients
at operation was 45 years (20 to 55). At ten years, four patients
had died and six were lost to follow-up, comprising ten hips. The
mean post-operative Harris hip score was 94.7 (55 to 100). Radiological
analysis was undertaken in 90 available THRs of the surviving 106
hips at final review: all had evidence of stable bony ingrowth,
with no cases of osteolysis. Wear was undetectable. There were four
revisions. The survival for both components with revision for any
cause as an endpoint was 96.5% (95% confidence interval 94.5 to
98.7). The mean modified University of California, Los Angeles activity
level rose from a mean of 6.4 (4 to 10) pre-operatively to 9.0 (6
to 10) at the ten-year post-operative period. Alumina ceramic-on-ceramic bearings in cementless primary THR
in this series have resulted in good clinical and radiological outcomes
with undetectable rates of wear and excellent function in the demanding
younger patient group at ten years. Cite this article:
The popularity of cementless total hip replacement
(THR) has surpassed cemented THR in England and Wales. This retrospective
cohort study records survival time to revision following primary
cementless THR with the most common combination (accounting for
almost a third of all cementless THRs), and explores risk factors independently
associated with failure, using data from the National Joint Registry
for England and Wales. Patients with osteoarthritis who had a DePuy
Corail/Pinnacle THR implanted between the establishment of the registry
in 2003 and 31 December 2010 were included within analyses. There
were 35 386 procedures. Cox proportional hazard models were used
to analyse the extent to which the risk of revision was related
to patient, surgeon and implant covariates. The overall rate of
revision at five years was 2.4% (99% confidence interval 2.02 to
2.79). In the final adjusted model, we found that the risk of revision
was significantly higher in patients receiving metal-on-metal (MoM:
hazard ratio (HR) 1.93, p <
0.001) and ceramic-on-ceramic bearings
(CoC: HR 1.55, p = 0.003) compared with the best performing bearing
(metal-on-polyethylene). The risk of revision was also greater for
smaller femoral stems (sizes 8 to 10: HR 1.82, p <
0.001) compared
with mid-range sizes. In a secondary analysis of only patients where body
mass index (BMI) data were available (n = 17 166), BMI ≥ 30 kg/m2 significantly
increased the risk of revision (HR 1.55, p = 0.002). The influence
of the bearing on the risk of revision remained significant (MoM:
HR 2.19, p <
0.001; CoC: HR 2.09,
p = 0.001). The risk of revision was independent of age, gender,
head size and offset, shell, liner and stem type, and surgeon characteristics. We found significant differences in failure between bearing surfaces
and femoral stem size after adjustment for a range of covariates
in a large cohort of single-brand cementless THRs. In this study
of procedures performed since 2003, hard bearings had significantly
higher rates of revision, but we found no evidence that head size
had an effect. Patient characteristics, such as BMI and American
Society of Anesthesiologists grade, also influence the survival
of cementless components. Cite this article:
A number of studies have reported satisfactory
results from the isolated revision of an acetabular component. However,
many of these studies reported only the short- to intermediate-term
results of heterogeneous bearing surfaces in a mixed age group. We present our experience of using a ceramic-on-ceramic (CoC)
bearing for isolated revision of an uncemented acetabular component
in 166 patients (187 hips) who were under the age of 50 years at
the time of revision. There were 78 men and 88 women with a mean
age of 47.4 years (28 to 49). The most common reason for revision
was polyethylene wear and acetabular osteolysis in 123 hips (66%),
followed by aseptic loosening in 49 hips (26%). We report the clinical and radiological outcome, complication
rate, and survivorship of this group. The mean duration of follow-up
was 15.6 years (11 to 19). The mean pre-operative Harris hip score was 33 points (1 to 58),
and improved to a mean of 88 points (51 to 100) at follow-up. The
mean pre-operative total Western Ontario and McMaster Universities
Osteoarthritis Index score was 63.2 (43 to 91) and improved to 19.8
points (9 to 61) post-operatively. Overall, 153 of 166 patients
(92%) were satisfied with their outcome. Kaplan–Meier survivorship
analysis, with revision or radiological evidence of implant failure
(13 patients, 8%) as end-points, was 92% at 15 years (95% confidence
interval 0.89 to 0.97). Isolated revision of a cementless acetabular component using
a CoC bearing gives good results in patients under 50 years of age. Cite this article:
The aim of this study was to compare early functional and health
related quality of life outcomes (HRQoL) in patients who have undergone
total hip arthroplasty (THA) using a bone conserving short stem
femoral component and those in whom a conventional length uncemented
component was used. Outcome was assessed using a validated performance
based outcome instrument as well as patient reported outcome measures
(PROMs). We prospectively analysed 33 patients whose THA involved a contemporary
proximally porous coated tapered short stem femoral component and
53 patients with a standard conventional femoral component, at a
minimum follow-up of two years. The mean follow-up was 31.4 months
(24 to 39). Patients with poor proximal femoral bone quality were
excluded. The mean age of the patients was 66.6 years (59 to 77)
and the mean body mass index was 30.2 kg/m2 (24.1 to
41.0). Outcome was assessed using the Oxford Hip Score (OHS) and
the University College Hospital (UCH) hip score which is a validated
performance based instrument. HRQoL was assessed using the EuroQol
5D (EQ-5D).Aims
Patients and Methods
The objective of this five-year prospective, blinded, randomised
controlled trial (RCT) was to compare femoral head penetration into
a vitamin E diffused highly cross-linked polyethylene (HXLPE) liner
with penetration into a medium cross-linked polyethylene control
liner using radiostereometric analysis. Patients scheduled for total hip arthroplasty (THA) were randomised
to receive either the study E1 (32 patients) or the control ArComXL
polyethylene (35 patients). The median age (range) of the overall
cohort was 66 years (40 to 76).Aims
Patients and Methods
Patients from a randomised trial on resurfacing
hip arthroplasty (RHA) (n = 36, 19 males; median age 57 years, 24
to 65) comparing a conventional 28 mm metal-on-metal total hip arthroplasty
(MoM THA) (n = 28, 17 males; median age 59 years, 37 to 65) and
a matched control group of asymptomatic patients with a 32 mm ceramic-on-polyethylene
(CoP) THA (n = 33, 18 males; median age 63 years, 38 to 71) were
cross-sectionally screened with metal artefact reducing sequence-MRI
(MARS-MRI) for pseudotumour formation at a median of 55 months (23
to 72) post-operatively. MRIs were scored by consensus according
to three different classification systems for pseudotumour formation. Clinical scores were available for all patients and metal ion
levels for MoM bearing patients. Periprosthetic lesions with a median volume of 16 mL (1.5 to
35.9) were diagnosed in six patients in the RHA group (17%), one
in the MoM THA group (4%) and six in the CoP group (18%). The classification
systems revealed no clear differences between the groups. Solid
lesions (n = 3) were exclusively encountered in the RHA group. Two patients
in the RHA group and one in the MoM THA group underwent a revision
for pseudotumour formation. There was no statistically significant
relationship between clinical scoring, metal ion levels and periprosthetic
lesions in any of the groups. Periprosthetic fluid collections are seen on MARS-MRI after conventional
CoP THA and RHA and may reflect a soft-tissue collection or effusion. Currently available MRI classification systems seem to score
these collections as pseudotumours, causing an-overestimatation
of the incidence of pseudotumours. Cite this article:
Fracture of a ceramic component in total hip
replacement is a rare but potentially catastrophic complication.
The incidence is likely to increase as the use of ceramics becomes
more widespread. We describe such a case, which illustrates how
inadequate initial management will lead to further morbidity and
require additional surgery. We present the case as a warning that
fracture of a ceramic component should be revised to another ceramic-on-ceramic
articulation in order to minimise the risk of further catastrophic
wear.
According to a report by Millennium Research Group in January 2011, the US orthopaedic extremity device market will generate over $4.6 billion in revenue by 2015.
Accurate placement of the acetabular component during total hip
arthroplasty (THA) is an important factor in the success of the
procedure. However, the reported accuracy varies greatly and is
dependent upon whether free hand or navigated techniques are used.
The aim of this study was to assess the accuracy of an instrument
system that incorporates 3D printed, patient-specific guides designed
to optimise the placement of the acetabular component. A total of 100 consecutive patients were prospectively enrolled
and the accuracy of placement of the acetabular component was measured
using post-operative CT scans.Aims
Patients and Methods
One goal of total hip arthroplasty is to restore normal hip anatomy.
The aim of this study was to compare displacement of the centre
of rotation (COR) using a standard reaming technique with a technique
in which the acetabulum was reamed immediately peripherally and
referenced off the rim. In the first cohort the acetabulum was reamed to the floor followed
by sequentially larger reamers. In the second cohort the acetabulum
was only reamed peripherally, starting with a reamer the same size
as the native femoral head. Anteroposterior pelvic radiographs were
analysed for acetabular floor depth and vertical and horizontal position
of the COR.Aims
Patients and Methods
Total hip replacement in patients with Gaucher’s disease with symptomatic osteonecrosis of the femoral head is controversial because of the high early failure rates. We describe four patients who had an uncemented total hip replacement following enzyme replacement therapy for a median of two years and one month (1 to 9.8 years) prior to surgery, and who remained on treatment. At operation, the bone had a normal appearance and consistency. Histopathological examination showed that, compared with previous biopsies of untreated Gaucher’s disease, the Gaucher cell infiltrate had decreased progressively with therapy, being replaced by normal adipose tissue. The surfaces of viable bone beyond the osteonecrotic areas showed osteoblasts, indicating remodelling. In one case acetabular revision was carried out after 11 years and eight months. The three remaining patients had a mean follow-up of six years and four months (3.3 to 12 years). We recommend initiating enzyme replacement therapy at least one to two years prior to total hip replacement to facilitate bone remodelling and to allow implantation of uncemented components in these young patients.