Periprosthetic joint infection (PJI) complicates
between 0.5% and 1.2% primary total hip arthroplasties (THAs) and
may have devastating consequences. The traditional assessment of
patients suffering from PJI has involved the serological study of
inflammatory markers and microbiological analysis of samples obtained
from the joint space. Treatment has involved debridement and revision
arthroplasty performed in either one or two stages. We present an update on the burden of PJI, strategies for its
diagnosis and treatment, the challenge of resistant organisms and
the need for definitive evidence to guide the treatment of PJI after
THA. Cite this article:
Advances in the treatment of periprosthetic joint
infections of the hip have once more pushed prosthesis preserving techniques
into the limelight. At the same time, the common infecting organisms
are evolving to become more resistant to conventional antimicrobial
agents. Whilst the epidemiology of resistant staphylococci is changing,
a number of recent reports have advocated the use of irrigation
and debridement and one-stage revision for the treatment of periprosthetic
joint infections due to resistant organisms. This review presents
the available evidence for the treatment of periprosthetic joint
infections of the hip, concentrating in particular on methicillin
resistant staphylococci. Cite this article:
The August 2012 Research Roundup360 looks at: PRP and chondrogenic differentiation; basic fibroblast growth factor; whether glucosamine works; randomised trials; ossification of the ligamentum flavum; treadmill running; inhibiting BMP antagonists; and whether NSAIDs delay union after all.
The August 2013 Trauma Roundup360 looks at: reverse oblique fractures do better with a cephalomedullary device; locking screws confer no advantage in tibial plateau fractures; it’s all about the radius of curvature; radius of curvature revisited; radial head replacement in complex elbow reconstruction; stem cells in early fracture haematoma; heterotrophic ossification in forearms; and Boston in perspective.
Recently, the use of metal-on-metal articulations
in total hip arthroplasty (THA) has led to an increase in adverse
events owing to local soft-tissue reactions from metal ions and
wear debris. While the majority of these implants perform well,
it has been increasingly recognised that a small proportion of patients
may develop complications secondary to systemic cobalt toxicity
when these implants fail. However, distinguishing true toxicity
from benign elevations in cobalt ion levels can be challenging. The purpose of this two part series is to review the use of cobalt
alloys in THA and to highlight the following related topics of interest:
mechanisms of cobalt ion release and their measurement, definitions
of pathological cobalt ion levels, and the pathophysiology, risk factors
and treatment of cobalt toxicity. Historically, these metal-on-metal
arthroplasties are composed of a chromium-cobalt articulation. The release of cobalt is due to the mechanical and oxidative
stresses placed on the prosthetic joint. It exerts its pathological
effects through direct cellular toxicity. This manuscript will highlight the pathophysiology of cobalt
toxicity in patients with metal-on-metal hip arthroplasties. Take home message: Patients with new or evolving hip symptoms
with a prior history of THA warrant orthopaedic surgical evaluation.
Increased awareness of the range of systemic symptoms associated
with cobalt toxicity, coupled with prompt orthopaedic intervention, may
forestall the development of further complications. Cite this article:
We analysed the clinical and radiological outcomes
of a new surgical technique for the treatment of heterozygote post-axial
metatarsal-type foot synpolydactyly with HOX-D13 genetic mutations
with a mean follow-up of 30.9 months (24 to 42). A total of 57 feet
in 36 patients (mean age 6.8 years (2 to 16)) were treated with
this new technique, which transfers the distal part of the duplicated
fourth metatarsal to the proximal part of the fifth metatarsal.
Clinical and radiological assessments were undertaken pre- and post-operatively
and any complications were recorded. Final outcomes were evaluated
according to the methods described by Phelps and Grogan. Forefoot width
was reduced and the lengths of the all reconstructed toes were maintained
after surgery. Union was achieved for all the metatarsal osteotomies
without any angular deformities. Outcomes at the final assessment
were excellent in 51 feet (89%) and good in six (11%). This newly
described surgical technique provides for painless, comfortable
shoe-wearing after a single, easy-to-perform operation with good
clinical, radiological and functional outcomes. Cite this article:
Clinical studies evaluating the effects of vitamin D alone or in combination with calcium on physical function, falls and fractures have been inconsistent. Vitamin D has, however, been the focus of much orthopaedic, trauma and endocrine research. Playing a central role in muscle and bone metabolism, some studies on Vitamin D therapies offer the tantalising suggestion of a reduction in falls and fractures simply with vitamin D supplementation. We review the background and evidence behind vitamin D.
The February 2014 Foot &
Ankle Roundup360 looks at: optimal medial malleolar fixation; resurfacing in the talus; predicting outcome in mobility ankles; whether mal-aligned ankles can be successfully replaced; cartilage colonisation in bipolar ankle grafts; CTs and proof of fusion; recalcitrant Achilles tendinopathy; and recurrent fifth metatarsal stress fractures.
In order to ensure safety of the cell-based therapy for bone
regeneration, we examined BM cells obtained from a total of 13 Sprague-Dawley (SD) green
fluorescent protein transgenic (GFP-Tg) rats were culture-expanded
in an osteogenic differentiation medium for three weeks. Osteoblast-like
cells were then locally transplanted with collagen scaffolds to
the rat model of segmental bone defect. Donor cells were also intravenously infused
to the normal Sprague-Dawley (SD) rats for systemic biodistribution.
The flow cytometric and histological analyses were performed for
cellular tracking after transplantation.Objectives
Methods
The long term biological effects of wear products
following total hip arthroplasty (THA) are unclear. However, the indications
for THA are expanding, with increasingly younger patients undergoing
the procedure. This prospective, randomised study compared two groups of patients
undergoing THA after being randomised to receive one of two different
bearing surfaces: metal-on-polyethylene (MoP) n = 22 and metal-on-metal
(MoM) n = 23. We investigated the relationship between three variables:
bearing surface (MoP Our results demonstrated significantly higher mean cobalt and
chromium (Co and Cr) blood levels in the MoM group at all follow-up
points following surgery (p <
0.01), but there were no significant
differences in the chromosomal aberration indices between MoM and
MoP at two or five years (two years: p = 0.56, p = 0.08, p = 0.91, p
= 0.51 and five years: p = 0.086, p = 0.73, p = 0.06, p = 0.34)
for translocations, breaks, loss and gain of chromosomes respectively.
Regression analysis showed a strong linear relationship between
Cr levels and the total chromosomal aberration indices in the MoM
group (R2 = 0.90016), but this was not as strong for
Co (R2 = 0.68991). In the MoP group, the analysis revealed
a poor relationship between Cr levels and the total chromosomal
aberration indices (R2 = 0.23908) but a slightly stronger
relationship for Co (R2 = 0.64292). Across both groups,
Spearman’s correlation detected no overall association between Co and Cr
levels and each of the studied chromosomal aberrations. There remains
no clear indication which THA bearing couple is the most biocompatible,
especially in young active patients. While THA continues to be very
successful at alleviating pain and restoring function, the long-term
biological implications of the procedure still require further scrutiny. Cite this article:
The peri-prosthetic tissue response to wear debris
is complex and influenced by various factors including the size, area
and number of particles. We hypothesised that the ‘biologically
active area’ of all metal wear particles may predict the type of
peri-prosthetic tissue response. Peri-prosthetic tissue was sampled from 21 patients undergoing
revision of a small diameter metal-on-metal (MoM) total hip arthroplasty
(THA) for aseptic loosening. An enzymatic protocol was used for
tissue digestion and scanning electron microscope was used to characterise
particles. Equivalent circle diameters and particle areas were calculated.
Histomorphometric analyses were performed on all tissue specimens.
Aspirates of synovial fluid were collected for analysis of the cytokine
profile analysis, and compared with a control group of patients
undergoing primary THA (n = 11) and revision of a failed ceramic-on-polyethylene
arthroplasty (n = 6). The overall distribution of the size and area of the particles
in both lymphocyte and
non-lymphocyte-dominated responses were similar; however, the subgroup
with lymphocyte-dominated peri-prosthetic tissue responses had a
significantly larger total number of particles. 14 cytokines (interleukin (IL)-1ß, IL-2, IL-4, IL-5, IL-6, IL-10,
IL-13, IL-17, interferon (IFN)-γ, and IFN-gamma-inducible protein
10), chemokines (macrophage inflammatory protein (MIP)-1α and MIP-1ß),
and growth factors (granulocyte macrophage colony stimulating factor
(GM-CSF) and platelet derived growth factor) were detected at significantly higher
levels in patients with metal wear debris compared with the control
group. Significantly higher levels for IL-1ß, IL-5, IL-10 and GM-CSF
were found in the subgroup of tissues from failed MoM THAs with
a lymphocyte-dominated peri-prosthetic response compared with those
without this response. These results suggest that the ‘biologically active area’ predicts
the type of
peri-prosthetic tissue response. The cytokines IL-1ß, IL-5, IL-10,
and GM-CSF are associated with lymphocyte-dominated tissue responses
from failed small-diameter MoM THA. Cite this article:
This Although many agents commonly injected into joints are chondrotoxic,
in this Cite this article:
We determined the frequency, rate and extent
of development of scoliosis (coronal plane deformity) in wheelchair-dependent
patients with Duchenne muscular dystrophy (DMD) who were not receiving
steroid treatment. We also assessed kyphosis and lordosis (sagittal
plane deformity). The extent of scoliosis was assessed on sitting anteroposterior
(AP) spinal radiographs in 88 consecutive non-ambulatory patients
with DMD. Radiographs were studied from the time the patients became
wheelchair-dependent until the time of spinal fusion, or the latest assessment
if surgery was not undertaken. Progression was estimated using a
longitudinal mixed-model regression analysis to handle repeated
measurements. Scoliosis ≥ 10° occurred in 85 of 88 patients (97%), ≥ 20° in
78 of 88 (89%) and ≥ 30° in 66 of 88 patients (75%). The fitted
longitudinal model revealed that time in a wheelchair was a highly
significant predictor of the magnitude of the curve, independent
of the age of the patient (p <
0.001). Scoliosis developed in
virtually all DMD patients not receiving steroids once they became
wheelchair-dependent, and the degree of deformity deteriorated over
time. In general, scoliosis increased at a constant rate, beginning
at the time of wheelchair-dependency (p <
0.001). In some there
was no scoliosis for as long as three years after dependency, but
scoliosis then developed and increased at a constant rate. Some
patients showed a rapid increase in the rate of progression of the
curve after a few years – the clinical phenomenon of a rapidly collapsing
curve over a few months. A sagittal plane kyphotic deformity was seen in 37 of 60 patients
(62%) with appropriate radiographs, with 23 (38%) showing lumbar
lordosis (16 (27%) abnormal and seven (11%) normal). This study provides a baseline to assess the effects of steroids
and other forms of treatment on the natural history of scoliosis
in patients with DMD, and an approach to assessing spinal deformity
in the coronal and sagittal planes in wheelchair-dependent patients
with other neuromuscular disorders. Cite this article:
Currently, there is no animal model in which
to evaluate the underlying physiological processes leading to the heterotopic
ossification (HO) which forms in most combat-related and blast wounds.
We sought to reproduce the ossification that forms under these circumstances
in a rat by emulating patterns of injury seen in patients with severe
injuries resulting from blasts. We investigated whether exposure
to blast overpressure increased the prevalence of HO after transfemoral
amputation performed within the zone of injury. We exposed rats
to a blast overpressure alone (BOP-CTL), crush injury and femoral
fracture followed by amputation through the zone of injury (AMP-CTL)
or a combination of these (BOP-AMP). The presence of HO was evaluated
using radiographs, micro-CT and histology. HO developed in none
of nine BOP-CTL, six of nine AMP-CTL, and in all 20 BOP-AMP rats.
Exposure to blast overpressure increased the prevalence of HO. This model may thus be used to elucidate cellular and molecular
pathways of HO, the effect of varying intensities of blast overpressure,
and to evaluate new means of prophylaxis and treatment of heterotopic
ossification. Cite this article:
The February 2014 Research Roundup360 looks at: blood supply to the femoral head after dislocation; diabetes and hip replacement; bone remodelling over two decades following hip replacement; sham surgery as good as arthroscopic meniscectomy; distraction in knee osteoarthritis; whether joint replacement prevent cardiac events; tranexamic acid and knee replacement haemostasis; cartilage colonisation in bipolar ankle grafts; CTs and proof of fusion; atorvastatin for muscle re-innervation after sciatic nerve transection; microfracture and short-term pain in cuff repair; promising early results from L-PRF augmented cuff repairs; and fatty degeneration in a rodent model.
The pathophysiology of intervertebral disc degeneration has been extensively studied. Various factors have been suggested as influencing its aetiology, including mechanical factors, such as compressive loading, shear stress and vibration, as well as ageing, genetic, systemic and toxic factors, which can lead to degeneration of the disc through biochemical reactions. How are these factors linked? What is their individual importance? There is no clear evidence indicating whether ageing in the presence of repetitive injury or repetitive injury in the absence of ageing plays a greater role in the degenerative process. Mechanical factors can trigger biochemical reactions which, in turn, may promote the normal biological changes of ageing, which can also be accelerated by genetic factors. Degradation of the molecular structure of the disc during ageing renders it more susceptible to superimposed mechanical injuries. This review supports the theory that degeneration of the disc has a complex multifactorial aetiology. Which factors initiate the events in the degenerative cascade is a question that remains unanswered, but most evidence points to an age-related process influenced primarily by mechanical and genetic factors.
Implant-associated infection is a major source
of morbidity in orthopaedic surgery. There has been extensive research
into the development of materials that prevent biofilm formation,
and hence, reduce the risk of infection. Silver nanoparticle technology
is receiving much interest in the field of orthopaedics for its
antimicrobial properties, and the results of studies to date are
encouraging. Antimicrobial effects have been seen when silver nanoparticles are
used in trauma implants, tumour prostheses, bone cement, and also
when combined with hydroxyapatite coatings. Although there are promising
results with Cite this article:
The June 2013 Research Roundup360 looks at: a contact patch to rim distance and metal ions; the matrix of hypoxic cartilage; CT assessment of early fracture healing; Hawthornes and radiographs; cardiovascular mortality and fragility fractures; and muscle strength decline preceding OA changes.
It has been proposed that intervertebral disc degeneration might be caused by low-grade infection. The purpose of the present study was to assess the incidence of herpes viruses in intervertebral disc specimens from patients with lumbar disc herniation. A polymerase chain reaction based assay was applied to screen for the DNA of eight different herpes viruses in 16 patients and two controls. DNA of at least one herpes virus was detected in 13 specimens (81.25%). Herpes Simplex Virus type-1 (HSV-1) was the most frequently detected virus (56.25%), followed by Cytomegalovirus (CMV) (37.5%). In two patients, co-infection by both HSV-1 and CMV was detected. All samples, including the control specimens, were negative for Herpes Simplex Virus type-2, Varicella Zoster Virus, Epstein Barr Virus, Human Herpes Viruses 6, 7 and 8. The absence of an acute infection was confirmed both at the serological and mRNA level. To our knowledge this is the first unequivocal evidence of the presence of herpes virus DNA in intervertebral disc specimens of patients with lumbar disc herniation suggesting the potential role of herpes viruses as a contributing factor to the pathogenesis of degenerative disc disease.
Between 1993 and 1994, 891 patients underwent
primary anterior cruciate ligament (ACL) reconstruction. A total
of 48 patients had undergone bilateral ACL reconstruction and
42 were available for review. These patients were matched to a unilateral
ACL reconstruction control group for gender, age, sport of primary
injury, meniscal status and graft type. At 15-year follow-up a telephone
interview with patients in both groups was performed. The incidence
of further ACL injury was identified through structured questions
and the two groups were compared for the variables of graft rupture
or further ACL injury, family history of ACL injury, International
Knee Documentation Committee (IKDC) subjective score and activity
level. There were 28 male and 14 female patients with a mean age of
25 years (13 to 42) at the time of first ACL injury. Subsequent
further ACL injury was identified in ten patients (24%) in the bilateral
ACL reconstruction study group and in nine patients (21%) in the
unilateral ACL reconstruction control group (p = 0.794). The mean
time from bilateral ACL reconstruction to further ACL injury was
54 months (6 to 103). There was no significant difference between
the bilateral ACL reconstruction study group and the matched unilateral
ACL reconstruction control group in incidence of further ACL injury
(p = 0.794), family history of ACL injury (p = 0.595), IKDC activity
level (p = 0.514), or IKDC subjective score (p = 0.824). After bilateral ACL reconstruction the incidence of graft rupture
and subjective outcomes were equivalent to that after unilateral
ACL reconstructions. Cite this article: