Total knee arthroplasty (TKA) is a common and safe orthopaedic procedure. Zimmer Biomet's NexGen is the second most popular brand of implant used in the UK. The primary cause of revision after the first year is aseptic loosening. We present our experience of using this implant, with significant concerns around its performance with regards early aseptic loosening of the tibial component. A retrospective, single-surgeon review was carried out of all of the NexGen Legacy Posterior Stabilized (LPS) TKAs performed in this institute. The specific model used for the index procedures was the NexGen Complete Knee System (Legacy Knee-Posterior Stabilized LPS-Flex Articular Surface, LPS-Flex Femoral Component Option, and Stemmed Nonaugmentable Tibial Component Option).Aims
Methods
Unicompartmental and total knee arthroplasty (UKA and TKA) are successful treatments for osteoarthritis, but the solid metal implants disrupt the natural distribution of stress and strain which can lead to bone loss over time. This generates problems if the implant needs to be revised. This study investigates whether titanium lattice UKA and TKA implants can maintain natural load transfer in the proximal tibia. In a cadaveric model, UKA and TKA procedures were performed on eight fresh-frozen knee specimens, using conventional (solid) and titanium lattice tibial implants. Stress at the bone-implant interfaces were measured and compared to the native knee.Aims
Methods
Reverse total shoulder arthroplasty (RTSA) using trabecular metal (TM)-backed glenoid implants has been introduced with the aim to increase implant survival. Only short-term reports on the outcomes of TM-RTSA have been published to date. We aim to present the seven-year survival of TM-backed glenoid implants along with minimum five-year clinical and radiological outcomes. All consecutive elective RTSAs performed at a single centre between November 2008 and October 2014 were reviewed. Patients who had primary TM-RTSA for rotator cuff arthropathy and osteoarthritis with deficient cuff were included. A total of 190 shoulders in 168 patients (41 male, 127 female) were identified for inclusion at a mean of 7.27 years (SD 1.4) from surgery. The primary outcome was survival of the implant with all-cause revision and aseptic glenoid loosening as endpoints. Secondary outcomes were clinical, radiological, and patient-related outcomes with a five-year minimum follow-up.Aims
Methods
The aim of this study is to report the 30 day COVID-19 related morbidity and mortality of patients assessed as SARS-CoV-2 negative who underwent emergency or urgent orthopaedic surgery in the NHS during the peak of the COVID-19 pandemic. A retrospective, single centre, observational cohort study of all patients undergoing surgery between 17 March 2020 and 3May 2020 was performed. Outcomes were stratified by British Orthopaedic Association COVID-19 Patient Risk Assessment Tool. Patients who were SARS-CoV-2 positive at the time of surgery were excluded.Introduction
Method
The aim of this study was to report the results of custom-made endoprostheses with extracortical plates plus or minus a short, intramedullary stem aimed at preserving the physis after resection of bone sarcomas in children. Between 2007 and 2017, 18 children aged less than 16 years old who underwent resection of bone sarcomas, leaving ≤ 5 cm of bone from the physis, and reconstruction with a custom-made endoprosthesis were reviewed. Median follow-up was 67 months (interquartile range 45 to 91). The tumours were located in the femur in 11 patients, proximal humerus in six, and proximal tibia in one.Aims
Patients and Methods
Calcium sulphate has traditionally been used as a filler of dead space arising during surgery. Various complications have been described following the use of Stimulan bio-absorbable calcium sulphate beads. This study is a prospective observational study to assess the safety profile of these beads when used in revision arthroplasty, comparing the complication rates with those reported in the literature. A total of 755 patients who underwent 456 revision total knee arthroplasties (TKA) and 299 revision total hip arthroplasties (THA), with a mean follow-up of 35 months (0 to 78) were included in the study.Aims
Methods
The purpose of this study was to assess early physical function
after total hip or knee arthroplasty (THA/TKA), and the correlation
between patient-reported outcome measures, physical performance
and actual physical activity (measured by actigraphy). A total of 80 patients aged 55 to 80 years undergoing THA or
TKA for osteoarthritis were included in this prospective cohort
study. The main outcome measure was change in patient reported hip
or knee injury and osteoarthritis outcome score (HOOS/KOOS) from
pre-operatively until post-operative day 13 (THA) or 20 (TKA). Secondary measures
were correlations to objectively assessed change in physical performance
(paced-walk, chair-stand, stair-climb tests) at day 14 (THA) or
21 (TKA) and actual physical activity (actigraphy) measured at day
12 and 13 (THA) or 19 and 20 (TKA). Aims
Patients and Methods
We compared the outcome of total hip arthroplasty (THA) in obese
patients who previously underwent bariatric surgery and those who
did not, in a matched cohort study. There were 47 THAs in the bariatric group (42 patients), and
94 THAs in the comparison group (92 patients). The mean age of the
patients was 57 years in both groups (24 to 79) and 57% of the patients
in both groups were women. The mean time between bariatric surgery
and THA was five years (four months to 12 years) in the bariatric group.
The mean follow-up after THA was three years (2 to 9). Aims
Patients and Methods
We describe the use of a protocol of irrigation and debridement
(I&
D) with retention of the implant for the treatment of periprosthetic
infection of a total elbow arthroplasty (TEA). This may be an attractive
alternative to staged re-implantation. Between 1990 and 2010, 23 consecutive patients were treated in
this way. Three were lost to follow-up leaving 20 patients (21 TEAs)
in the study. There were six men and 14 women. Their mean age was
58 years (23 to 76). The protocol involved: component unlinking,
irrigation and debridement (I&
D), and the introduction of antibiotic
laden cement beads; organism-specific intravenous antibiotics; repeat
I&
D and re-linkage of the implant if appropriate; long-term
oral antibiotic therapy. Aims
Patients and Methods
Until now, there has been no consensus as to whether stemmed
acetabular components are appropriate for use in patients undergoing
revision total hip arthroplasty (THA) who have major acetabular
defects or pelvic discontinuity. We wished to address this deficiency
in the literature. We carried out a retrospective study of 35 patients (six men
and 29 women) with a mean age of 68 years (37 to 87), with major
acetabular defects who underwent revision THA between 2000 and 2012.Aim
Patients and Methods
The aim of this study was to establish what happens to patients
in the long term after endoprosthetic replacement for a primary
malignant tumour of bone. We conducted a retrospective analysis of a prospectively maintained
database to identify all patients who had undergone an endoprosthetic
replacement more than 25 years ago and who were still alive. Their
outcomes were investigated with reference to their complications and
need for further surgery. A total of 230 patients were identified.
Their mean age at diagnosis was 20.7 years (five to 62). The most
common diagnosis was osteosarcoma (132). The most common site was
the distal femur (102). Aims
Patients and 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.
The optimal management of intracapsular fractures of the femoral
neck in independently mobile patients remains open to debate. Successful
fixation obviates the limitations of arthroplasty for this group
of patients. However, with fixation failure rates as high as 30%,
the outcome of revision surgery to salvage total hip arthroplasty
(THA) must be considered. We carried out a systematic review to
compare the outcomes of salvage THA and primary THA for intracapsular
fractures of the femoral neck. We performed a Preferred Reporting Items for Systematic Reviews
and Meta-Analysis (PRISMA) compliant systematic review, using the
PubMed, EMBASE and Cochrane libraries databases. A meta-analysis
was performed where possible, and a narrative synthesis when a meta-analysis
was not possible.Aims
Patients and Methods
We review our experience of Coonrad-Morrey total elbow arthroplasty
(TEA) for fractures of the distal humerus in non-rheumatoid patients
with a minimum of ten years follow-up. TEA through a triceps splitting approach was peformed in 37 non-rheumatoid
patients for a fracture of the distal humerus between 1996 and 2004.
One patient could not be traced and 17 had died before the tenth
anniversary of their surgery. This left 19 patients with a minimum
follow-up of ten years to form the study group. Of these, 13 patients
were alive at the time of final review. The other six had died,
but after the tenth anniversary of their elbow arthroplasty. Their
clinical and radiological data were included in the study. Aims
Patients and Methods
We investigated changes in the axial alignment of the ipsilateral
hip and knee after total hip arthroplasty (THA). We reviewed 152 patients undergoing primary THA (163 hips; 22
hips in men, 141 hips in women) without a pre-operative flexion
contracture. The mean age was 64 years (30 to 88). The diagnosis
was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary
to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach
with repair of the external rotators was used in 134 hips and an
anterior approach in 29 hips. We measured changes in leg length
and offset on radiographs, and femoral anteversion, internal rotation
of the hip and lateral patellar tilt on CT scans, pre- and post-operatively. Aims
Patients and Methods
Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters.Objectives
Methods
