We have carried out a prospective, randomised study designed to compare the long-term stability of the stem of
The aim of this study was to determine the stability of a new
short femoral stem compared with a conventional femoral stem in
patients undergoing cementless total hip arthroplasty (THA), in
a prospective randomized controlled trial using radiostereometric
analysis (RSA). A total of 53 patients were randomized to receive cementless
THA with either a short femoral stem (MiniHip, 26 patients, mean
age: 52 years, nine male) or a conventional length femoral stem
(MetaFix, 23 patients, mean age: 53 years, 11 male). All patients
received the same cementless acetabular component. Two-year follow-up
was available on 38 patients. Stability was assessed through migration
and dynamically inducible micromotion. Radiographs for RSA were
taken postoperatively and at three, six, 12, 18, and 24 months.Aims
Patients and Methods
The primary stability of the cementless Oxford Unicompartmental Knee Replacement (OUKR) relies on interference fit (or press fit). Insufficient interference may cause implant loosening, whilst excessive interference could cause bone damage and fracture. The aim of this study was to identify the optimal interference fit by measuring the force required to seat the tibial component of the cementless OUKR (push-in force) and the force required to remove the component (pull-out force). Six cementless OUKR tibial components were implanted in 12 new slots prepared on blocks of solid polyurethane foam (20 pounds per cubic foot (PCF), Sawbones, Malmo, Sweden) with a range of interference of 0.1 mm to 1.9 mm using a Dartec materials testing machine HC10 (Zwick Ltd, Herefordshire, United Kingdom) . The experiment was repeated with cellular polyurethane foam (15 PCF), which is a more porous analogue for trabecular bone.Objectives
Materials and Methods
Enhanced micromotions between the implant and surrounding bone can impair osseointegration, resulting in fibrous encapsulation and aseptic loosening of the implant. Since the effect of micromotions on human bone cells is sparsely investigated, an Micromotions ranging from 25 µm to 100 µm were applied as sine or triangle signal with 1 Hz frequency to human osteoblasts seeded on collagen scaffolds. Micromotions were applied for six hours per day over three days. During the micromotions, a static pressure of 527 Pa was exerted on the cells by Ti6Al4V cylinders. Osteoblasts loaded with Ti6Al4V cylinders and unloaded osteoblasts without micromotions served as controls. Subsequently, cell viability, expression of the osteogenic markers collagen type I, alkaline phosphatase, and osteocalcin, as well as gene expression of osteoprotegerin, receptor activator of NF-κB ligand, matrix metalloproteinase-1, and tissue inhibitor of metalloproteinase-1, were investigated.Objectives
Methods
As the number of younger and more active patients
treated with total knee arthroplasty (TKA) continues to increase,
consideration of better fixation as a means of improving implant
longevity is required. Cemented TKA remains the reference standard
with the largest body of evidence and the longest follow-up to support
its use. However, cementless TKA, may offer the opportunity of a
more bone-sparing procedure with long lasting biological fixation
to the bone. We undertook a review of the literature examining advances
of cementless TKA and the reported results. Cite this article:
Bactericidal levels of antibiotics are difficult
to achieve in infected total joint arthroplasty when intravenous antibiotics
or antibiotic-loaded cement spacers are used, but intra-articular
(IA) delivery of antibiotics has been effective in several studies.
This paper describes a protocol for IA delivery of antibiotics in
infected knee arthroplasty, and summarises the results of a pharmacokinetic
study and two clinical follow-up studies of especially difficult
groups: methicillin-resistant Cite this article:
A retrospective review was performed of patients
undergoing primary cementless total knee replacement (TKR) using
porous tantalum performed by a group of surgical trainees. Clinical
and radiological follow-up involved 79 females and 26 males encompassing
115 knees. The mean age was 66.9 years (36 to 85). Mean follow-up
was 7 years (2 to 11). Tibial and patellar components were porous
tantalum monoblock implants, and femoral components were posterior
stabilised (PS) in design with cobalt–chromium fibre mesh. Radiological
assessments were made for implant positioning, alignment, radiolucencies,
lysis, and loosening. There was 95.7% survival of implants. There
was no radiological evidence of loosening and no osteolysis found.
No revisions were performed for aseptic loosening. Average tibial
component alignment was 1.4° of varus (4°of valgus to 9° varus),
and 6.2° (3° anterior to 15° posterior) of posterior slope. Mean
femoral component alignment was 6.6° (1° to 11°) of valgus. Mean tibiofemoral
alignment was 5.6° of valgus (7° varus to 16° valgus). Patellar
tilt was a mean of 2.4° lateral (5° medial to 28° lateral). Patient
satisfaction with improvement in pain was 91%. Cementless TKR incorporating
porous tantalum yielded good clinical and radiological outcomes
at a mean of follow-up of seven-years. Cite this article:
This study reports on the first 150 consecutive
Oxford cementless unicompartmental knee arthroplasties (UKA) performed
in an independent centre (126 patients). All eligible patients had
functional scores (Oxford knee score and high activity arthroplasty
score) recorded pre-operatively and at two- and five-years of follow-up. Fluoroscopically
aligned radiographs were taken at five years and analysed for any
evidence of radiolucent lines (RLLs), subsidence or loosening. The
mean age of the cohort was 63.6 years (39 to 86) with 81 (53.1%)
males. Excellent functional scores were maintained at five years
and there were no progressive RLLs demonstrated on radiographs.
Two patients underwent revision to a total knee arthroplasty giving
a revision rate of 0.23/100 (95% confidence interval 0.03 to 0.84)
component years with overall component survivorship of 98.7% at
five years. There were a further four patients who underwent further
surgery on the same knee, two underwent bearing exchanges for dislocation
and two underwent lateral UKAs for disease progression. This was
a marked improvement from other UKAs reported in New Zealand Joint
Registry data and supports the designing centre’s early results. Cite this article:
Pelvic reconstruction after the resection of a tumour around
the acetabulum is a challenging procedure due to the complex anatomy
and biomechanics. Several pelvic endoprostheses have been introduced,
but the rates of complication remain high. Our aim was to review
the use of a stemmed acetabular pedestal cup in the management of
these patients. The study involved 48 patients who underwent periacetabular reconstruction
using a stemmed pedestal cup (Schoellner cup; Zimmer Biomet Inc.,
Warsaw, Indiana) between 2000 and 2013. The indications for treatment included
a primary bone tumour in 27 patients and metastatic disease in 21
patients. The mean age of the patients at the time of surgery was
52 years (16 to 83).Aims
Patients and Methods
To determine the effect of a change in design of a cementless
ceramic acetabular component in fixation and clinical outcome after
total hip arthroplasty We compared 342 hips (302 patients) operated between 1999 and
2005 with a relatively smooth hydroxyapatite coated acetabular component
(group 1), and 337 hips (310 patients) operated between 2006 and
2011 using a similar acetabular component with a macrotexture on
the entire outer surface of the component (group 2). The mean age of
the patients was 53.5 (14 to 70) in group 1 and 53.0 (15 to 70)
in group 2. The mean follow-up was 12.7 years (10 to 17) for group
1 and 7.2 years (4 to 10) for group 2.Aims
Patients and Methods
The aim of this study was to identify patient- and surgery-related
risk factors for sustaining an early periprosthetic fracture following
primary total hip arthroplasty (THA) performed using a double-tapered
cementless femoral component (Bi-Metric femoral stem; Biomet Inc.,
Warsaw, Indiana). A total of 1598 consecutive hips, in 1441 patients receiving
primary THA between January 2010 and June 2015, were retrospectively
identified. Level of pre-operative osteoarthritis, femoral Dorr
type and cortical index were recorded. Varus/valgus placement of
the stem and canal fill ratio were recorded post-operatively. Periprosthetic
fractures were identified and classified according to the Vancouver
classification. Regression analysis was performed to identify risk
factors for early periprosthetic fracture.Aims
Patients and Methods
We report on the outcome of the Synergy cementless femoral stem
with a minimum follow-up of 15 years (15 to 17). A retrospective review was undertaken of a consecutive series
of 112 routine primary cementless total hip arthroplasties (THAs)
in 102 patients (112 hips). There were 60 female and 42 male patients
with a mean age of 61 years (18 to 82) at the time of surgery. A
total of 78 hips in the 69 patients remain Aims
Patients and Methods
The primary purpose of this study of metal-on-metal
(MoM) hip resurfacing was to compare the effect of using a cementless
or cemented femoral component on the subsequent bone mineral density
(BMD) of the femoral neck. This was a single-centre, prospective, double-blinded control
trial which randomised 120 patients (105 men and 15 women) with
a mean age of 49.4 years (21 to 68) to receive either a cemented
or cementless femoral component. Follow-up was to two years. Outcome
measures included total and six-point region-of-interest BMD of
the femoral neck, radiological measurements of acetabular inclination,
neck-shaft and stem-shaft angles, and functional outcome scores
including the Harris hip score, the Western Ontario and McMaster
Universities Osteoarthritis Index and the University of California
at Los Angeles activity scale. In total, 17 patients were lost to follow-up leaving 103 patients
at two years. There were no revisions in the cementless group and
three revisions (5%) in the cemented group (two because of hip pain
and one for pseudotumour). The total BMD was significantly higher in the cementless group
at six months (p <
0.001) and one year (p = 0.01) than in the
cemented group, although there was a loss of statistical significance
in the difference at two years (p = 0.155). All patient outcomes improved significantly: there were no significant
differences between the two groups. The results show better preservation of femoral neck BMD with
a cementless femoral component after two years of follow-up. Further
investigation is needed to establish whether this translates into
improved survivorship. Cite this article:
Periprosthetic joint infection (PJI) is a devastating
complication for patients and results in greatly increased costs
of care for both healthcare providers and patients. More than 15
500 revision hip and knee procedures were recorded in England, Wales
and Northern Ireland in 2013, with infection accounting for 13%
of revision hip and 23% of revision knee procedures. We report our experience of using antibiotic eluting absorbable
calcium sulphate beads in 15 patients (eight men and seven women
with a mean age of 64.8 years; 41 to 83) as part of a treatment
protocol for PJI in revision arthroplasty. The mean follow-up was 16 months (12 to 22). We report the outcomes
and complications, highlighting the risk of hypercalcaemia which
occurred in three patients. We recommend that serum levels of calcium be routinely sought
following the implantation of absorbable calcium sulphate beads
in orthopaedic surgery. Cite this article:
