Taper junctions between modular hip arthroplasty femoral heads and stems fail by wear or corrosion which can be caused by relative motion at their interface. Increasing the assembly force can reduce relative motion and corrosion but may also damage surrounding tissues. The purpose of this study was to determine the effects of increasing the impaction energy and the stiffness of the impactor tool on the stability of the taper junction and on the forces transmitted through the patient’s surrounding tissues. A commercially available impaction tool was modified to assemble components in the laboratory using impactor tips with varying stiffness at different applied energy levels. Springs were mounted below the modular components to represent the patient. The pull-off force of the head from the stem was measured to assess stability, and the displacement of the springs was measured to assess the force transmitted to the patient’s tissues.Objectives
Methods
Tantalum (Ta) trabecular metal components are increasingly used
to reconstruct major bone defects in revision arthroplasty surgery.
It is known that some metals such as silver have antibacterial properties.
Recent reports have raised the question regarding whether Ta components
are protective against infection in revision surgery. This laboratory
study aimed to establish whether Ta has intrinsic antibacterial
properties against planktonic bacteria, or the ability to inhibit
biofilm formation. Equal-sized pieces of Ta and titanium (Ti) acetabular components
were sterilised and incubated with a low dose inoculum of either Aims
Materials and Methods
Mesenchymal stem cells have the ability to differentiate into various cell types, and thus have emerged as promising alternatives to chondrocytes in cell-based cartilage repair methods. The aim of this experimental study was to investigate the effect of bone marrow derived mesenchymal stem cells combined with platelet rich fibrin on osteochondral defect repair and articular cartilage regeneration in a canine model. Osteochondral defects were created on the medial femoral condyles of 12 adult male mixed breed dogs. They were either treated with stem cells seeded on platelet rich fibrin or left empty. Macroscopic and histological evaluation of the repair tissue was conducted after four, 16 and 24 weeks using the International Cartilage Repair Society macroscopic and the O’Driscoll histological grading systems. Results were reported as mean and standard deviation (Objectives
Methods
To clarify the asymmetrical ossification of the epiphyseal ring
between the convex and concave sides in patients with adolescent
idiopathic scoliosis (AIS). A total of 29 female patients (mean age, 14.4 years; 11 to 18)
who underwent corrective surgery for AIS (Lenke type 1 or 2) were
included in our study. In all, 349 vertebrae including 68 apical
vertebrae and 87 end vertebrae in the main thoracic (MT) curve and
thoracolumbar/lumbar (TL/L) curve were analysed. Coronal sections
(anterior, middle and posterior) of the vertebral bodies were reconstructed
from pre-operative CT scans (320-row detector; slice thickness,
0.5 mm) and the appearances of the ossification centre in the epiphyseal
ring at four corners were evaluated in three groups; all vertebrae
excluding end vertebrae, apical vertebrae and end vertebrae. The appearance
rates of the ossification centre at the concave and convex sides
were calculated and compared.Aims
Patients and Methods
Initial stability of tibial trays is crucial for long-term success of total knee arthroplasty (TKA) in both primary and revision settings. Rotating platform (RP) designs reduce torque transfer at the tibiofemoral interface. We asked if this reduced torque transfer in RP designs resulted in subsequently reduced micromotion at the cemented fixation interface between the prosthesis component and the adjacent bone. Composite tibias were implanted with fixed and RP primary and revision tibial trays and biomechanically tested under up to 2.5 kN of axial compression and 10° of external femoral component rotation. Relative micromotion between the implanted tibial tray and the neighbouring bone was quantified using high-precision digital image correlation techniques.Objectives
Methods
Although atlantoaxial rotatory fixation (AARF) is a common cause
of torticollis in children, the diagnosis may be delayed. The condition
is characterised by a lack of rotation at the atlantoaxial joint
which becomes fixed in a rotated and subluxed position. The management of
children with a delayed presentation of this condition is controversial.
This is a retrospective study of a group of such children. Children who were admitted to two institutions between 1988 and
2014 with a diagnosis of AARF were included. We identified 12 children
(four boys, eight girls), with a mean age of 7.3 years (1.5 to 13.4),
in whom the duration of symptoms on presentation was at least four weeks
(four to 39). All were treated with halo traction followed by a
period of cervical immobilisation in a halo vest or a Minerva jacket.
We describe a simple modification to the halo traction that allows
the child to move their head whilst maintaining traction. The mean follow-up
was 59.6 weeks (24 to 156).Aims
Patients and 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
The accurate reconstruction of hip anatomy and
biomechanics is thought to be important in achieveing good clinical
outcomes following total hip arthroplasty (THA). To this end some
newer hip designs have introduced further modularity into the design
of the femoral component such that neckshaft angle and anteversion,
which can be adjusted intra-operatively. The clinical effect of
this increased modularity is unknown. We have investigated the changes
in these anatomical parameters following conventional THA with a
prosthesis of predetermined neck–shaft angle and assessed the effect
of changes in the hip anatomy on clinical outcomes. In total, 44 patients (mean age 65.3 years (standard deviation
( The mean pre-operative neck–shaft angle was significantly increased
by 2.8° from 128° ( Cite this article:
The aim of this study was a quantitative analysis of a surgeon’s
learning curve for scoliosis surgery and the relationship between
the surgeon’s experience and post-operative outcomes, which has
not been previously well described. We have investigated the operating time as a function of the
number of patients to determine a specific pattern; we analysed
factors affecting the operating time and compared intra- and post-operative
outcomes. We analysed 47 consecutive patients undergoing scoliosis
surgery performed by a single, non-trained scoliosis surgeon. Operating time
was recorded for each of the four parts of the procedures: dissection,
placement of pedicle screws, reduction of the deformity and wound
closure.Aims
Patients and Methods
Favourable results for collarless polished tapered stems have been reported, and cement creep due to taper slip may be a contributing factor. However, the ideal cement thickness around polished stems remains unknown. We investigated the influence of cement thickness on stem subsidence and cement creep. We cemented six collarless polished tapered (CPT) stems (two stems each of small, medium and large sizes) into composite femurs that had been reamed with a large CPT rasp to achieve various thicknesses of the cement mantle. Two or three tantalum balls were implanted in the proximal cement in each femur. A cyclic loading test was then performed for each stem. The migration of the balls was measured three-dimensionally, using a micro-computed tomography (CT) scanner, before and after loading. A digital displacement gauge was positioned at the stem shoulder, and stem subsidence was measured continuously by the gauge. Final stem subsidence was measured at the balls at the end of each stem.Objectives
Methods
The primary aim of this study was to analyse the position of
the acetabular and femoral components in total hip arthroplasty
undertaken using an anterior surgical approach. In a prospective, single centre study, we used the EOS imaging
system to analyse the position of components following THA performed
via the anterior approach in 102 patients (103 hips) with a mean
age of 64.7 years (Aims
Patients and Methods
Throughout the 20th Century, it has been postulated that the knee moves on the basis of a four-bar link mechanism composed of the cruciate ligaments, the femur and the tibia. As a consequence, the femur has been thought to roll back with flexion, and total knee arthroplasty (TKA) prostheses have been designed on this basis. Recent work, however, has proposed that at a position of between 0° and 120° the medial femoral condyle does not move anteroposteriorly whereas the lateral femoral condyle tends, but is not obliged, to roll back – a combination of movements which equates to tibial internal/ femoral external rotation with flexion. The aim of this paper was to assess if the articular geometry of the GMK Sphere TKA could recreate the natural knee movements The pattern of knee movement was studied in 15 patients (six male: nine female; one male with bilateral TKAs) with 16 GMK Sphere implants, at a mean age of 66 years (53 to 76) with a mean BMI of 30 kg/m2 (20 to 35). The motions of all 16 knees were observed using pulsed fluoroscopy during a number of weight-bearing and non-weight-bearing static and dynamic activities.Objectives
Methods
Periacetabular osteotomy is an effective way of treating symptomatic
hip dysplasia. We describe a new minimally invasive technique using
a modification of the Smith-Peterson approach. We performed a prospective, longitudinal cohort study to assess
for any compromise in acetabular correction when using this approach,
and to see if the procedure would have a higher complication rate
than that quoted in the literature for other approaches. We also
assessed for any improvement in functional outcome. From 168 consecutive patients (189 hips) who underwent acetabular
correction between March 2010 and March 2013 we excluded those who
had undergone previous pelvic surgery for DDH and those being treated
for acetabular retroversion. The remaining 151 patients (15 men,
136 women) (166 hips) had a mean age of 32 years (15 to 56) and the
mean duration of follow-up was 2.8 years (1.2 to 4.5). In all 90%
of cases were Tönnis grade 0 or 1. Functional outcomes were assessed
using the Non Arthritic Hip Score (NAHS), University of California,
Los Angeles (UCLA) and Tegner activity scores.Aims
Patients and Methods
The major problem with repair of an articular cartilage injury
is the extensive difference in the structure and function of regenerated,
compared with normal cartilage. Our work investigates the feasibility
of repairing articular osteochondral defects in the canine knee
joint using a composite lamellar scaffold of nano-ß-tricalcium phosphate
(ß-TCP)/collagen (col) I and II with bone marrow stromal stem cells
(BMSCs) and assesses its biological compatibility. The bone–cartilage scaffold was prepared as a laminated composite,
using hydroxyapatite nanoparticles (nano-HAP)/collagen I/copolymer
of polylactic acid–hydroxyacetic acid as the bony scaffold, and
sodium hyaluronate/poly(lactic-co-glycolic acid) as the cartilaginous
scaffold. Ten-to 12-month-old hybrid canines were randomly divided
into an experimental group and a control group. BMSCs were obtained
from the iliac crest of each animal, and only those of the third
generation were used in experiments. An articular osteochondral
defect was created in the right knee of dogs in both groups. Those
in the experimental group were treated by implanting the composites
consisting of the lamellar scaffold of ß-TCP/col I/col II/BMSCs.
Those in the control group were left untreated.Objectives
Methods
We reviewed 34 consecutive patients (18 female-16 male) with
isthmic spondylolysis and grade I to II lumbosacral spondylolisthesis
who underwent in situ posterolateral arthodesis between the L5 transverse
processes and the sacral ala with the use of iliac crest autograft.
Ten patients had an associated scoliosis which required surgical correction
at a later stage only in two patients with idiopathic curves unrelated
to the spondylolisthesis. No patient underwent spinal decompression or instrumentation
placement. Mean surgical time was 1.5 hours (1 to 1.8) and intra-operative
blood loss 200 ml (150 to 340). There was one wound infection treated
with antibiotics but no other complication. Radiological assessment
included standing posteroanterior and lateral, Ferguson and lateral flexion/extension
views, as well as CT scans. Aims
Methods
We investigated the incidence of anomalies in
the vertebral arteries and Circle of Willis with three-dimensional
CT angiography in 55 consecutive patients who had undergone an instrumented
posterior fusion of the cervical spine. We recorded any peri-operative and post-operative complications.
The frequency of congenital anomalies was 30.9%, abnormal vertebral
artery blood flow was 58.2% and vertebral artery dominance 40%. The posterior communicating artery was occluded on one side in
41.8% of patients and bilaterally in 38.2%. Variations in the vertebral
arteries and Circle of Willis were not significantly related to
the presence or absence of posterior communicating arteries. Importantly,
18.2% of patients showed characteristic variations in the Circle
of Willis with unilateral vertebral artery stenosis or a dominant
vertebral artery, indicating that injury may cause lethal complications.
One patient had post-operative cerebellar symptoms due to intra-operative
injury of the vertebral artery, and one underwent a different surgical
procedure because of insufficient collateral circulation. Pre-operative assessment of the vertebral arteries and Circle
of Willis is essential if a posterior spinal fusion with instrumentation
is to be carried out safely. Cite this article:
The objective of this study was to evaluate the rotation and
translation of each joint in the hindfoot and compare the load response
in healthy feet with that in stage II posterior tibial tendon dysfunction
(PTTD) flatfoot by analysing the reconstructive three-dimensional
(3D) computed tomography (CT) image data during simulated weight-bearing. CT scans of 15 healthy feet and 15 feet with stage II PTTD flatfoot
were taken first in a non-weight-bearing condition, followed by
a simulated full-body weight-bearing condition. The images of the
hindfoot bones were reconstructed into 3D models. The ‘twice registration’
method in three planes was used to calculate the position of the
talus relative to the calcaneus in the talocalcaneal joint, the
navicular relative to the talus in talonavicular joint, and the cuboid
relative to the calcaneus in the calcaneocuboid joint.Objective
Methods
This study compared the quality of reduction
and complication rate when using a standard ilioinguinal approach and
the new pararectus approach when treating acetabular fractures surgically.
All acetabular fractures that underwent fixation using either approach
between February 2005 and September 2014 were retrospectively reviewed
and the demographics of the patients, the surgical details and complications
were recorded. A total of 100 patients (69 men, 31 women; mean age 57 years,
18 to 93) who were consecutively treated were included for analysis.
The quality of reduction was assessed using standardised measurement
of the gaps and steps in the articular surface on pre- and post-operative
CT-scans. There were no significant differences in the demographics of
the patients, the surgical details or the complications between
the two approaches. A significantly better reduction of the gap,
however, was achieved with the pararectus approach (axial: p = 0.025,
coronal: p = 0.013, sagittal: p = 0.001). These data suggest that the pararectus approach is at least equal
to, or in the case of reduction of the articular gap, superior to
the ilioinguinal approach. This approach allows direct buttressing of the dome of the acetabulum
and the quadrilateral plate, which is particularly favourable in
geriatric fracture patterns. Cite this article:
We sought to determine if a durable bilayer implant composed of trabecular metal with autologous periosteum on top would be suitable to reconstitute large osteochondral defects. This design would allow for secure implant fixation, subsequent integration and remodeling. Adult sheep were randomly assigned to one of three groups (n = 8/group): 1. trabecular metal/periosteal graft (TMPG), 2. trabecular metal (TM), 3. empty defect (ED). Cartilage and bone healing were assessed macroscopically, biochemically (type II collagen, sulfated glycosaminoglycan (sGAG) and double-stranded DNA (dsDNA) content) and histologically.Objectives
Materials and Methods
