Recently, high failure rates of metal-on-metal (MOM) hip implants have raised concerns of cobalt toxicity. Adverse reactions occur to cobalt nanoparticles (CoNPs) and cobalt ions (Co2+) during wear of MOM hip implants, but the toxic mechanism is not clear. To evaluate the protective effect of zinc ions (Zn2+), Balb/3T3 mouse fibroblast cells were pretreated with 50 μM Zn2+ for four hours. The cells were then exposed to different concentrations of CoNPs and Co2+ for four hours, 24 hours and 48 hours. The cell viabilities, reactive oxygen species (ROS) levels, and inflammatory cytokines were measured.Objectives
Methods
Ultraviolet (UV) light-mediated photofunctionalisation is known to improve osseointegration of pure titanium (Ti). However, histological examination of titanium alloy (Ti6Al4V), which is frequently applied in orthopaedic and dental surgery, has not yet been performed. This study examined the osseointegration of photofunctionalised Ti6Al4V implants. Ti and Ti6Al4V implants were treated with UV light, and the chemical composition and contact angle on the surfaces were evaluated to confirm photofunctionalisation. The implants were inserted into femurs in rats, and the rats were killed two or four weeks after the surgery. For histomorphometric analysis, both the bone–implant contact (BIC) ratio and the bone volume (BV) ratio were calculated from histological analysis and microcomputed tomography data.Objectives
Methods
Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the We describe a method for the study of bacterial adherence in the presence of preosteoblastic cells. For this purpose we mixed different concentrations of bacterial cells from collection and clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells, and analysed the minimal concentration of bacteria able to colonise the surface of the material with image analysis.Objectives
Methods
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.
Anatomical total knee arthroplasty alignment
Deep bone and joint infections (DBJI) are directly intertwined with health, demographic change towards an elderly population, and wellbeing. The elderly human population is more prone to acquire infections, and the consequences such as pain, reduced quality of life, morbidity, absence from work and premature retirement due to disability place significant burdens on already strained healthcare systems and societal budgets. DBJIs are less responsive to systemic antibiotics because of poor vascular perfusion in necrotic bone, large bone defects and persistent biofilm-based infection. Emerging bacterial resistance poses a major threat and new innovative treatment modalities are urgently needed to curb its current trajectory. We present a new biphasic ceramic bone substitute consisting of hydroxyapatite and calcium sulphate for local antibiotic delivery in combination with bone regeneration. Gentamicin release was measured in four setups: 1) Objectives
Materials and Methods
This study aimed to characterise and qualitatively grade the severity of the corrosion particles released into the hip joint following taper corrosion. The 26 cases examined were CoC/ABG Modular (n = 13) and ASR/SROM (n = 13). Blood serum metal ion levels were collected before and after revision surgery. The haematoxylin and eosin tissue sections were graded on the presence of fibrin exudates, necrosis, inflammatory cells and corrosion products. The corrosion products were identified based on visible observation and graded on abundance. Two independent observers blinded to the clinical patient findings scored all cases. Elemental analysis was performed on corrosion products within tissue sections. X-Ray diffraction was used to identify crystalline structures present in taper debris.Objectives
Methods
Few reports compare the contribution of the talonavicular articulation
to overall range of movement in the sagittal plane after total ankle
arthroplasty (TAA) and tibiotalar arthrodesis. The purpose of this
study was to assess changes in ROM and functional outcomes following
tibiotalar arthrodesis and TAA. Patients who underwent isolated tibiotalar arthrodesis or TAA
with greater than two-year follow-up were enrolled in the study.
Overall arc of movement and talonavicular movement in the sagittal
plane were assessed with weight-bearing lateral maximum dorsiflexion
and plantarflexion radiographs. All patients completed Short Form-12
version 2.0 questionnaires, visual analogue scale for pain (VAS)
scores, and the Foot and Ankle Ability Measure (FAAM).Aims
Patients and Methods
We explored the literature surrounding whether
allergy and hypersensitivity has a clinical basis for implant selection
in total knee arthroplasty (TKA). In error, the terms hypersensitivity
and allergy are often used synonymously. Although a relationship
is present, we could not find any evidence of implant failure due
to allergy. There is however increasing basic science that suggests
a link between loosening and metal ion production. This is not an
allergic response but is a potential problem. With a lack of evidence
logically there can be no justification to use ‘hypoallergenic’
implants in patients who have pre-existing skin sensitivity to the
metals used in TKA. Cite this article:
There are many guidelines that help direct the management of
patients with metal-on-metal (MOM) hip arthroplasties. We have undertaken
a study to compare the management of patients with MOM hip arthroplasties in
different countries. Six international tertiary referral orthopaedic centres were
invited to participate by organising a multi-disciplinary team (MDT)
meeting, consisting of two or more revision hip arthroplasty surgeons
and a musculoskeletal radiologist. A full clinical dataset including
history, blood tests and imaging for ten patients was sent to each
unit, for discussion and treatment planning. Differences in the
interpretation of findings, management decisions and rationale for
decisions were compared using quantitative and qualitative methods.Aims
Methods
This study compares the outcomes of two methods
of fixation of displaced fractures of the radial neck. The 58 patients
with a mean age of 38.5 years (18 to 56), were treated in a non
randomised study with screws (n = 29) or a plate and screws (n =
29) according to the surgeon’s preference. The patients were reviewed at one year. Radiographs and functional
evaluations were carried out up to one year post-operatively, using
the Broberg and Morrey functional evaluation score, range of movement,
and assessment of complications. The mean functional scores did not differ significantly between
groups (90 (55 to 100) Cite this article:
The purpose of this study was to evaluate A total of 60 Sprague-Dawley rats (125 g to 149 g) were implanted
subcutaneously with SWCNT/PLAGA composites (10 mg SWCNT and 1gm
PLAGA 12 mm diameter two-dimensional disks), and at two, four, eight
and 12 weeks post-implantation were compared with control (Sham)
and PLAGA (five rats per group/point in time). Rats were observed
for signs of morbidity, overt toxicity, weight gain and food consumption,
while haematology, urinalysis and histopathology were completed
when the animals were killed.Objectives
Methods
The LockDown device (previously called Surgilig)
is a braided polyester mesh which is mostly used to reconstruct the
dislocated acromioclavicular joint. More than 11 000 have been implanted
worldwide. Little is known about the tissue reaction to the device
nor to its wear products when implanted in an extra-articular site
in humans. This is of importance as an adverse immunological reaction
could result in osteolysis or damage to the local tissues, thereby affecting
the longevity of the implant. We analysed the histology of five LockDown implants retrieved
from five patients over the last seven years by one of the senior
authors. Routine analysis was carried out in all five cases and
immunohistochemistry in one. The LockDown device acts as a scaffold for connective tissue
which forms an investing fibrous pseudoligament. The immunological
response at the histological level seems favourable with a limited
histiocytic and giant cell response to micron-sized wear particles.
The connective tissue envelope around the implant is less organised
than a native ligament. Cite this article:
The purpose of this study was to compare the
diagnostic accuracy for the detection of infection between the culture of
fluid obtained by sonication (SFC) and the culture of peri-implant
tissues (PITC) in patients with early and delayed implant failure,
and those with unsuspected and suspected septic failure. It was
hypothesised that SFC increases the diagnostic accuracy for infection
in delayed, but not early, implant failure, and in unsuspected septic
failure. The diagnostic accuracy for infection of all consecutive
implants (hardware or prostheses) that were removed for failure was
compared between SFC and PITC. This prospective study included 317
patients with a mean age of 62.7 years (9 to 97). The sensitivity
for detection of infection using SFC was higher than using PITC
in an overall comparison (89.9% Sonication is mainly recommended when there is implant failure
with no clear signs of infection and in patients with delayed implant
failure. In early failure, SFC is not superior to PITC for the diagnosis
of infection and, therefore, is not recommended as a routine diagnostic
test in these patients. Cite this article:
We reviewed the outcome of 69 uncemented, custom-made,
distal femoral endoprosthetic replacements performed in 69 patients
between 1994 and 2006. There were 31 women and 38 men with a mean
age at implantation of 16.5 years (5 to 37). All procedures were
performed for primary malignant bone tumours of the distal femur.
At a mean follow-up of 124.2 months (4 to 212), 53 patients were
alive, with one patient lost to follow-up. All nine implants (13.0%)
were revised due to aseptic loosening at a mean of 52 months (8
to 91); three implants (4.3%) were revised due to fracture of the
shaft of the prosthesis and three patients (4.3%) had a peri-prosthetic
fracture. Bone remodelling associated with periosteal cortical thinning
adjacent to the uncemented intramedullary stem was seen in 24 patients
but this did not predispose to failure. All aseptically loose implants
in this series were diagnosed to be loose within the first five
years. The results from this study suggest that custom-made uncemented
distal femur replacements have a higher rate of aseptic loosening
compared to published results for this design when used with cemented
fixation. Loosening of uncemented replacements occurs early indicating
that initial fixation of the implant is crucial. Cite this article:
Objectives. An experimental rabbit model was used to test the null hypothesis,
that there is no difference in new bone formation around uncoated
titanium discs compared with coated titanium discs when implanted
into the muscles of rabbits. Methods. A total of three titanium discs with different surface and coating
(1, porous coating; 2, porous coating + Bonemaster (Biomet); and
3, porous coating + plasma-sprayed hydroxyapatite) were implanted
in 12 female rabbits. Six animals were killed after six weeks and
the remaining six were killed after 12 weeks. The
We have developed an animal model to examine the formation of heterotopic ossification using standardised muscular damage and implantation of a beta-tricalcium phosphate block into a hip capsulotomy wound in Wistar rats. The aim was to investigate how cells originating from drilled femoral canals and damaged muscles influence the formation of heterotopic bone. The femoral canal was either drilled or left untouched and a tricalcium phosphate block, immersed either in saline or a rhBMP-2 solution, was implanted. These implants were removed at three and 21 days after the operation and examined histologically, histomorphometrically and immunohistochemically. Bone formation was seen in all implants in rhBMP-2-immersed, whereas in those immersed in saline the process was minimal, irrespective of drilling of the femoral canals. Bone mineralisation was somewhat greater in the absence of drilling with a mean mineralised volume to mean total volume of 18.2% ( Our findings suggest that osteoinductive signalling is an early event in the formation of ectopic bone. If applicable to man the results indicate that careful tissue handling is more important than the prevention of the dissemination of bone cells in order to avoid heterotopic ossification.
The direct anterior approach in total hip replacement anatomically offers the chance to minimise soft-tissue trauma because an intermuscular and internervous plane is explored. This motivated us to abandon our previously used transgluteal approach and to adopt the direct anterior approach for total hip replacement. Using MRI, we performed a retrospective comparative study of the direct anterior approach with the transgluteal approach. There were 25 patients in each group. At one year post-operatively all the patients underwent MRI of their replaced hips. A radiologist graded the changes in the soft-tissue signals in the abductor muscles. The groups were similar in terms of age, gender, body mass index, complexity of the reconstruction and absence of symptoms. Detachment of the abductor insertion, partial tears and tendonitis of gluteus medius and minimus, the presence of peri-trochanteric bursal fluid and fatty atrophy of gluteus medius and minimus were significantly less pronounced and less frequent when the direct anterior approach was used. There was no significant difference in the findings regarding tensor fascia lata between the two approaches. We conclude that use of the direct anterior approach results in a better soft-tissue response as assessed by MRI after total hip replacement. However, the impact on outcome needs to be evaluated further.
Intra-operative, peri-articular injection of
local anaesthesia is an increasingly popular way of controlling
pain following total knee replacement. The evidence from this study suggests that it is safe to use
peri-articular injection in combination with auto-transfusion of
blood from peri-articular drains during knee replacement surgery.
We have reviewed five adult patients treated with endoprosthetic reconstruction of the proximal radius following resection of non-traumatic lesions. The patients had a mean age of 33.4 years (20 to 60) at the time of surgery and the mean follow-up was 7.6 years (0.8 to 16). Following surgery, all elbows were clinically stable and there was 100% survivorship of the prosthesis. Evaluation of function was assessed clinically and by the Mayo Elbow Performance Score, achieving a mean of 86% (70 to 100). Results at medium-term follow-up are encouraging with regards to elbow stability, implant survivorship and functional outcome.