Pathological assessment of periprosthetic tissues is important, not only for diagnosis, but also for understanding the pathobiology of implant failure. The host response to wear particle deposition in periprosthetic tissues is characterised by cell and tissue injury, and a reparative and inflammatory response in which there is an innate and adaptive immune response to the material components of implant wear. Physical and chemical characteristics of implant wear influence the nature of the response in periprosthetic tissues and account for the development of particular complications that lead to implant failure, such as osteolysis which leads to aseptic loosening, and soft-tissue necrosis/inflammation, which can result in pseudotumour formation. The innate response involves phagocytosis of implant-derived wear particles by macrophages; this is determined by pattern recognition receptors and results in expression of cytokines, chemokines and growth factors promoting inflammation and osteoclastogenesis; phagocytosed particles can also be cytotoxic and cause cell and tissue necrosis. The adaptive immune response to wear debris is characterised by the presence of lymphoid cells and most likely occurs as a result of a cell-mediated hypersensitivity reaction to cell and tissue components altered by interaction with the material components of particulate wear, particularly metal ions released from cobalt-chrome wear particles. Cite this article: Professor N. A. Athanasou. The pathobiology and pathology of aseptic implant failure.
Ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA)
are commonly used, but concerns exist regarding ceramic fracture.
This study aims to report the risk of revision for fracture of modern
CoC bearings and identify factors that might influence this risk,
using data from the National Joint Registry (NJR) for England, Wales, Northern
Ireland and the Isle of Man. We analysed data on 223 362 bearings from 111 681 primary CoC
THAs and 182 linked revisions for bearing fracture recorded in the
NJR. We used implant codes to identify ceramic bearing composition
and generated Kaplan-Meier estimates for implant survivorship. Logistic
regression analyses were performed for implant size and patient specific
variables to determine any associated risks for revision.Aims
Patients and Methods
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
Long-term clinical outcomes for ceramic-on-ceramic (CoC) bearings
are encouraging. However, there is a risk of squeaking. Guidelines
for the orientation of the acetabular component are defined from
static imaging, but the position of the pelvis and thus the acetabular
component during activities associated with edge-loading are likely
to be very different from those measured when the patient is supine.
We assessed the functional orientation of the acetabular component. A total of 18 patients with reproducible squeaking in their CoC
hips during deep flexion were investigated with a control group
of 36 non-squeaking CoC hips. The two groups were matched for the
type of implant, the orientation of the acetabular component when
supine, the size of the femoral head, ligament laxity, maximum hip
flexion and body mass index. Aims
Patients and Methods
Compared with primary total hip arthroplasty (THA), revision
surgery can be challenging. The cement-in-cement femoral revision
technique involves removing a femoral component from a well-fixed
femoral cement mantle and cementing a new stem into the original
mantle. This technique is widely used and when carried out for the
correct indications, is fast, relatively inexpensive and carries
a reduced short-term risk for the patient compared with the alternative
of removing well-fixed cement. We report the outcomes of this procedure
when two commonly used femoral stems are used. We identified 1179 cement-in-cement stem revisions involving
an Exeter or a Lubinus stem reported to the Swedish Hip Arthroplasty
Register (SHAR) between January 1999 and December 2015. Kaplan-Meier
survival analysis was performed.Aims
Patients and Methods
The use of ceramic femoral heads in total hip arthroplasty (THA) has increased due to their proven low bearing wear characteristics. Ceramic femoral heads are also thought to reduce wear and corrosion at the head-stem junction with titanium (Ti) stems when compared with metal heads. We sought to evaluate taper damage of ceramic compared with metal heads when paired with cobalt chromium (CoCr) alloy stems in a single stem design. This retrieval study involved 48 total hip arthroplasties (THAs) with CoCr V40 trunnions paired with either CoCr (n = 21) or ceramic (n = 27) heads. The taper junction of all hips was evaluated for fretting/corrosion damage and volumetric material loss using a roundness-measuring machine. We used linear regression analysis to investigate taper damage differences after adjusting for potential confounding variables.Objectives
Methods
Few studies have assessed outcomes following non-metal-on-metal hip arthroplasty (non-MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD). We assessed outcomes following non-MoMHA revision surgery performed for ARMD, and identified predictors of re-revision. We performed a retrospective observational study using data from the National Joint Registry for England and Wales. All non-MoMHAs undergoing revision surgery for ARMD between 2008 and 2014 were included (185 hips in 185 patients). Outcome measures following ARMD revision were intra-operative complications, mortality and re-revision surgery. Predictors of re-revision were identified using Cox regression.Objectives
Methods
Ceramic-on-metal (CoM) is a relatively new bearing
combination for total hip arthroplasty (THA) with few reported outcomes.
A total of 287 CoM THAs were carried out in 271 patients (mean age
55.6 years (20 to 77), 150 THAs in female patients, 137 in male)
under the care of a single surgeon between October 2007 and October
2009. With the issues surrounding metal-on-metal bearings the decision
was taken to review these patients between March and November 2011,
at a mean follow-up of 34 months (23 to 45) and to record pain,
outcome scores, radiological analysis and blood ion levels. The
mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268
hips (95%) had mild/very mild/no pain, the mean angle of inclination
of the acetabular component was 44.8o (28o to
63o), 82 stems (29%) had evidence of radiolucent lines
of >
1 mm in at least one Gruen zone and the median levels of cobalt
and chromium ions in the blood were 0.83 μg/L (0.24 μg/L to 27.56 μg/L)
and 0.78 μg/L (0.21 μg/L to 8.84 μg/L), respectively. The five-year
survival rate is 96.9% (95% confidence interval 94.7% to 99%). Due to the presence of radiolucent lines and the higher than
expected levels of metal ions in the blood, we would not recommend
the use of CoM THA without further long-term follow-up. We plan
to monitor all these patients regularly. Cite this article:
The aims of this study were: firstly, to investigate the influence
of the thickness of cartilage at the sigmoid notch on the inclination
of the distal radioulnar joint (DRUJ), and secondly, to compare
the sensitivity and specificity of MRI with plain radiographs for
the assessment of the inclination of the articular surface of the
DRUJ in the coronal plane. Contemporaneous MRI images and radiographs of 100 wrists from
98 asymptomatic patients (mean age 43 years, (16 to 67); 52 male,
53%) with no history of a fracture involving the wrist or surgery
to the wrist, were reviewed. The thickness of the cartilage at the
sigmoid notch, inclination of the DRUJ and Tolat Type of each DRUJ
were determined. Aims
Patients and Methods
We present the clinical and radiological results at a minimum
follow-up of five years for patients who have undergone multiple
cement-in-cement revisions of their femoral component at revision
total hip arthroplasty (THA). We reviewed the outcome on a consecutive series of 24 patients
(10 men, 14 women) (51 procedures) who underwent more than one cement-in-cement
revision of the same femoral component. The mean age of the patients was
67.5 years (36 to 92) at final follow-up. Function was assessed using the original Harris hip score (HHS),
Oxford Hip Score (OHS) and the Merle D’Aubigné Postel score (MDP).Aims
Patients and Methods
A failed total ankle arthroplasty (TAA) is often associated with
much bone loss. As an alternative to arthrodesis, the surgeon may
consider a custom-made talar component to compensate for the bone
loss. Our aim in this study was to assess the functional and radiological
outcome after the use of such a component at mid- to long-term follow-up. A total of 12 patients (five women and seven men, mean age 53
years; 36 to77) with a failed TAA and a large talar defect underwent
a revision procedure using a custom-made talar component. The design
of the custom-made components was based on CT scans and standard
radiographs, when compared with the contralateral ankle. After the
anterior talocalcaneal joint was fused, the talar component was
introduced and fixed to the body of the calcaneum.Aims
Patients and Methods
Initial stability of tibial trays is crucial for long-term success of total knee arthroplasty (TKA) in both primary and revision settings. Rotating platform (RP) designs reduce torque transfer at the tibiofemoral interface. We asked if this reduced torque transfer in RP designs resulted in subsequently reduced micromotion at the cemented fixation interface between the prosthesis component and the adjacent bone. Composite tibias were implanted with fixed and RP primary and revision tibial trays and biomechanically tested under up to 2.5 kN of axial compression and 10° of external femoral component rotation. Relative micromotion between the implanted tibial tray and the neighbouring bone was quantified using high-precision digital image correlation techniques.Objectives
Methods
Excision of the proximal femur for tumour with
prosthetic reconstruction using a bipolar femoral head places a considerable
load on the unreplaced acetabulum. We retrospectively reviewed the changes which occur around the
affected hip joint by evaluating the post-operative radiographs
of 65 consecutive patients who underwent proximal prosthetic arthroplasty
of the femur, and in whom an acetabular component had not been used.
There were 37 men and 28 women with a mean age of 57.3 years (17
to 93). Radiological assessment included the extent of degenerative
change in the acetabulum, heterotopic ossification, and protrusio
acetabuli. The mean follow-up was 9.1 years (2 to 11.8). Degenerative changes
in the acetabulum were seen in three patients (4.6%), Brooker grade
1 or 2 heterotopic ossification in 17 (26%) and protrusion of the
prosthetic head in nine (13.8%). A total of eight patients (12.3%) needed a revision. Five were
revised to the same type of prosthesis and three (4.6%) were converted
to a total hip arthroplasty. We conclude that radiological evidence of degenerative change,
heterotopic ossification and protrusion occur in a few patients
who undergo prosthetic arthroplasty of the proximal femur for tumour.
The limited extent of these changes and the lack of associated symptoms
do not justify the routine arthroplasty of the acetabulum in these patients. Cite this article:
We undertook a retrospective cohort study to
determine clinical outcomes following the revision of metal-on-metal (MoM)
hip replacements for adverse reaction to metal debris (ARMD), and
to identify predictors of time to revision and outcomes following
revision. Between 1998 and 2012 a total of 64 MoM hips (mean age
at revision of 57.8 years; 46 (72%) female; 46 (72%) hip resurfacings
and 18 (28%) total hip replacements) were revised for ARMD at one specialist
centre. At a mean follow-up of 4.5 years (1.0 to 14.6) from revision
for ARMD there were 13 hips (20.3%) with post-operative complications
and eight (12.5%) requiring re-revision. The Kaplan–Meier five-year survival rate for ARMD revision was
87.9% (95% confidence interval 78.9 to 98.0; 19 hips at risk). Excluding
re-revisions, the median absolute Oxford hip score (OHS) following
ARMD revision using the percentage method (0% best outcome and 100%
worst outcome) was 18.8% (interquartile range (IQR) 7.8% to 48.3%),
which is equivalent to 39/48 (IQR 24.8/48 to 44.3/48) when using
the modified OHS. Histopathological response did not affect time
to revision for ARMD (p = 0.334) or the subsequent risk of re-revision
(p = 0.879). Similarly, the presence or absence of a contralateral
MoM hip bearing did not affect time to revision for ARMD (p = 0.066)
or the subsequent risk of re-revision (p = 0.178). Patients revised to MoM bearings had higher rates of re-revision
(five of 16 MoM hips re-revised; p = 0.046), but those not requiring
re-revision had good functional results (median absolute OHS 14.6%
or 41.0/48). Short-term morbidity following revision for ARMD was
comparable with previous reports. Caution should be exercised when choosing
bearing surfaces for ARMD revisions. Cite this article:
We evaluated the short-term functional outcome and prevalence
of bearing-specific generation of audible noise in 301 patients
(336 hips) operated on with fourth generation (Delta) medium diameter
head, ceramic-on-ceramic (CoC) total hip arthroplasties (THAs). There were 191 female (63%) and 110 male patients (37%) with
a mean age of 61 years (29 to 78) and mean follow-up of 2.1 years
(1.3 to 3.4). Patients completed three questionnaires: Oxford Hip
Score (OHS), Research and Development 36-item health survey (RAND-36)
and a noise-specific symptom questionnaire. Plain radiographs were also
analysed. A total of three hips (0.9%) were revised. Aims
Patients and Methods
As adverse events related to metal on metal hip
arthroplasty have been better understood, there has been increased
interest in toxicity related to the high circulating levels of cobalt ions.
However, distinguishing true toxicity from benign elevations in
cobalt levels can be challenging. The purpose of this review is
to examine the use of cobalt alloys in total hip arthroplasty, to
review the methods of measuring circulating cobalt levels, to define
a level of cobalt which is considered pathological and to review
the pathophysiology, risk factors and treatment of cobalt toxicity.
To the best of our knowledge, there are 18 published cases where
cobalt metal ion toxicity has been attributed to the use of cobalt-chromium
alloys in hip arthroplasty. Of these cases, the great majority reported
systemic toxic reactions at serum cobalt levels more than 100 μg/L.
This review highlights some of the clinical features of cobalt toxicity,
with the goal that early awareness may decrease the risk factors
for the development of cobalt toxicity and/or reduce its severity. Take home message: Severe adverse events can arise from the release
of cobalt from metal-on-metal arthroplasties, and as such, orthopaedic
surgeons should not only be aware of the presenting problems, but
also have the knowledge to treat appropriately. Cite this article:
Arthritis of the wrist is a painful disabling
condition that has various causes and presentations. The traditional treatment
has been a total wrist fusion at a price of the elimination of movement.
However, forms of treatment which allow the preservation of movement
are now preferred. Modern arthroplasties of the wrist are still
not sufficiently robust to meet the demands of many patients, nor
do they restore normal kinematics of the wrist. A preferable compromise
may be selective excision and partial fusion of the wrist using
knowledge of the aetiology and pattern of degenerative change to
identify which joints can be sacrificed and which can be preserved. This article provides an overview of the treatment options available
for patients with arthritis of the wrist and an algorithm for selecting
an appropriate surgical strategy. Cite this article:
