Rotator cuff tears are among the most common and debilitating
upper extremity injuries. Chronic cuff tears result in atrophy and
an infiltration of fat into the muscle, a condition commonly referred
to as ‘fatty degeneration’. While stem cell therapies hold promise
for the treatment of cuff tears, a suitable immunodeficient animal
model that could be used to study human or other xenograft-based
therapies for the treatment of rotator cuff injuries had not previously
been identified. A full-thickness, massive supraspinatus and infraspinatus tear
was induced in adult T-cell deficient rats. We hypothesised that,
compared with controls, 28 days after inducing a tear we would observe
a decrease in muscle force production, an accumulation of type IIB
fibres, and an upregulation in the expression of genes involved
with muscle atrophy, fibrosis and inflammation.Objectives
Methods
Tissues from five patients who underwent revision operations for failed total hip replacements were found to contain large quantities of particulate titanium. In four cases this metal must have come from titanium alloy screws used to fix the acetabular component; in the fifth case it may also have originated from a titanium alloy femoral head. Monoclonal antibody labelling showed abundant macrophages and
Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings. A matched case-control study was performed using the prospectively-collected database at the host institution. In all, 16 MoM hip resurfacing 'cases' were identified as having symptomatic periprosthetic pseudotumours on preoperative metal artefact reduction sequence (MARS) MRI, and were subsequently histologically confirmed as high-grade aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) at revision surgery. ‘Controls’ were matched by implant type in the absence of evidence of pseudotumour. Blood samples from all cases and controls were collected prospectively for high resolution genetic a nalysis targeting 11 separate HLA loci. Statistical significance was set at 0.10 a priori to determine the association between HLA genotype and pseudotumour formation, given the small sample size.Aims
Methods
Metal allergy in knee arthroplasty patients is a controversial topic. We aimed to conduct a scoping review to clarify the management of metal allergy in primary and revision total knee arthroplasty (TKA). Studies were identified by searching electronic databases: Cochrane Central Register of Controlled Trials, Ovid MEDLINE, and Embase, from their inception to November 2020, for studies evaluating TKA patients with metal hypersensitivity/allergy. All studies reporting on diagnosing or managing metal hypersensitivity in TKA were included. Data were extracted and summarized based on study design, study population, interventions and outcomes. A practical guide is then formulated based on the available evidence.Aims
Methods
A balanced inflammatory response is important for successful fracture healing. The response of osteoporotic fracture healing is deranged and an altered inflammatory response can be one underlying cause. The objectives of this review were to compare the inflammatory responses between normal and osteoporotic fractures and to examine the potential effects on different healing outcomes. A systematic literature search was conducted with relevant keywords in PubMed, Embase, and Web of Science independently. Original preclinical studies and clinical studies involving the investigation of inflammatory response in fracture healing in ovariectomized (OVX) animals or osteoporotic/elderly patients with available full text and written in English were included. In total, 14 articles were selected. Various inflammatory factors were reported; of those tumour necrosis factor-α (TNF-α) and interleukin (IL)-6 are two commonly studied markers. Preclinical studies showed that OVX animals generally demonstrated higher systemic inflammatory response and poorer healing outcomes compared to normal controls (SHAM). However, it is inconclusive if the local inflammatory response is higher or lower in OVX animals. As for clinical studies, they mainly examine the temporal changes of the inflammatory stage or perform comparison between osteoporotic/fragility fracture patients and normal subjects without fracture. Our review of these studies emphasizes the lack of understanding that inflammation plays in the altered fracture healing response of osteoporotic/elderly patients. Taken together, it is clear that additional studies, preclinical and clinical, are required to dissect the regulatory role of inflammatory response in osteoporotic fracture healing. Cite this article:
This study aimed to examine the effects of tumour necrosis factor-alpha (TNF-α) on osteoblasts in metal wear-induced bone loss. TNF-α immunoexpression was examined in periprosthetic tissues of patients with failed metal-on-metal hip arthroplasties and also in myeloid MM6 cells after treatment with cobalt ions. Viability and function of human osteoblast-like SaOs-2 cells treated with recombinant TNF-α were studied by immunofluorescence, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay, western blotting, and enzyme-linked immunosorbent assay (ELISA).Aims
Methods
The diagnosis of periprosthetic joint infection (PJI) is difficult and requires a battery of tests and clinical findings. The purpose of this review is to summarize all current evidence for common and new serum biomarkers utilized in the diagnosis of PJI. We searched two literature databases, using terms that encompass all hip and knee arthroplasty procedures, as well as PJI and statistical terms reflecting diagnostic parameters. The findings are summarized as a narrative review.Objectives
Methods
External fixation is widely used in orthopaedic
and trauma surgery. Infections around pin or wire sites, which are usually
localised, non-invasive, and are easily managed, are common. Occasionally,
more serious invasive complications such as necrotising fasciitis
(NF) and toxic shock syndrome (TSS) may occur. We retrospectively reviewed all patients who underwent external
fixation between 1997 and 2012 in our limb lengthening and reconstruction
programme. A total of eight patients (seven female and one male)
with a mean age of 20 years (5 to 45) in which pin/wire track infections
became limb- or life-threatening were identified. Of these, four
were due to TSS and four to NF. Their management is described. A
satisfactory outcome was obtained with early diagnosis and aggressive
medical and surgical treatment. Clinicians caring for patients who have external fixation and
in whom infection has developed should be aware of the possibility
of these more serious complications. Early diagnosis and aggressive
treatment are required in order to obtain a satisfactory outcome. Cite this article:
T-cells are considered to play an important role in the inflammatory response causing arthroplasty failure. The study objectives were to investigate the composition and distribution of CD4+ T-cell phenotypes in the peripheral blood (PB) and synovial fluid (SF) of patients undergoing revision surgery for failed metal-on-metal (MoM) and metal-on-polyethylene (MoP) hip arthroplasties, and in patients awaiting total hip arthroplasty. In this prospective case-control study, PB and SF were obtained from 22 patients (23 hips) undergoing revision of MoM (n = 14) and MoP (n = 9) hip arthroplasties, with eight controls provided from primary hip osteoarthritis cases awaiting arthroplasty. Lymphocyte subtypes in samples were analysed using flow cytometry.Objectives
Methods
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:
We have studied the relationship between metal ion levels and lymphocyte counts in patients with metal-on-metal hip resurfacings. Peripheral blood samples were analysed for lymphocyte subtypes and whole blood cobalt and chromium ion levels in 68 patients (34 with metal-on-metal hip resurfacings and 34 with standard metal-on-polyethylene total hip replacements). All hip components were radiologically well-fixed and the patients were asymptomatic. Cobalt and chromium levels were significantly elevated in the patients with metal-on-metal hip resurfacings, compared with the patients with standard metal-on-polyethylene designs (p <
0.0001). There was a statistically significant decrease in the level of CD8+ cells (T-cytotoxic/suppressor) (p = 0.005) in the metal-on-metal hip resurfacing group. A threshold level of blood cobalt and chromium ions was associated with reduced CD8+ T-cell counts. We have no evidence that our patients suffered as a result of this reduced level of CD8+ T-cells.
We carried out a cross-sectional study with analysis of the demographic, clinical and laboratory characteristics of patients with metal-on-metal hip resurfacing, ceramic-on-ceramic and metal-on-polyethylene hip replacements. Our aim was to evaluate the relationship between metal-on-metal replacements, the levels of cobalt and chromium ions in whole blood and the absolute numbers of circulating lymphocytes. We recruited 164 patients (101 men and 63 women) with hip replacements, 106 with metal-on-metal hips and 58 with non-metal-on-metal hips, aged <
65 years, with a pre-operative diagnosis of osteoarthritis and no pre-existing immunological disorders. Laboratory-defined T-cell lymphopenia was present in13 patients (15%) (CD8+ lymphopenia) and 11 patients (13%) (CD3+ lymphopenia) with unilateral metal-on-metal hips. There were significant differences in the absolute CD8+ lymphocyte subset counts for the metal-on-metal groups compared with each control group (p-values ranging between 0.024 and 0.046). Statistical modelling with analysis of covariance using age, gender, type of hip replacement, smoking and circulating metal ion levels, showed that circulating levels of metal ions, especially cobalt, explained the variation in absolute lymphocyte counts for almost all lymphocyte subsets.
A 70-year-old man with an uncemented metal-on-polyethylene
total hip prosthesis underwent revision arthroplasty 33 months later
because of pain, swelling and recurrent dislocation. There appeared
to be corrosion and metal release from the prosthetic head, resulting
in pseudotumour formation and severe local soft-tissue destruction.
The corrosion occurred at the junction between the titanium-molybdenum-zirconium-iron
taper and the cobalt-chrome-molybdenum head, but the mechanism was unproven.
An 86-year-old male presented with a loose total hip replacement (THR) ten years after implantation. At revision for anticipated aseptic loosening, watery pus was found in the joint and Bacille-Calmette-Guérin (BCG) was seen on culture. The bacterial strain was identified and was identical to the BCG used in the intravesicular treatment of superficial bladder carcinoma in this patient ten months earlier. After revision he received a full course of antituberculous treatment. The clinical and radiological results were excellent after follow-up for 30 months with his uncemented THR showing satisfactory incorporation. His inflammatory markers were normal and his Harris hip score was 95 points. The diagnosis of a tuberculous infection can be easily missed, but must be considered, especially if sterile pus is encountered.
