To validate the precision of digitally reconstructed radiograph (DRR) radiostereometric analysis (RSA) and the model-based method (MBM) RSA with respect to benchmark marker-based (MM) RSA for evaluation of kinematics in the native hip joint. Seven human cadaveric hemipelves were CT scanned and bone models were segmented. Tantalum beads were placed in the pelvis and proximal femoral bone. RSA recordings of the hips were performed during flexion, adduction and internal rotation. Stereoradiographic recordings were all analyzed with DRR, MBM and MM. Migration results for the MBM and DRR with respect to MM were compared. Precision was assessed as systematic bias (mean difference) and random variation (Pitman’s test for equal variance).Objectives
Methods
Aims
Patients and Methods
This study reports the mid-term results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head (LDH) ceramic-on-ceramic (CoC) bearing. Of the 276 hips (246 patients) included in this study, 264 (96%) were reviewed at a mean of 67 months (48 to 79) postoperatively. Procedures were performed with a mini posterior approach. Clinical and radiological outcomes were recorded at regular intervals. A noise assessment questionnaire was completed at last follow-up.Aims
Patients and Methods
A flexed knee gait is common in patients with bilateral spastic
cerebral palsy and occurs with increased age. There is a risk for
the recurrence of a flexed knee gait when treated in childhood,
and the aim of this study was to investigate whether multilevel
procedures might also be undertaken in adulthood. At a mean of 22.9 months (standard deviation 12.9), after single
event multi level surgery, 3D gait analysis was undertaken pre-
and post-operatively for 37 adult patients with bilateral cerebral
palsy and a fixed knee gait.Aims
Patients and Methods
Hydroxyapatite coatings for uncemented fixation in total knee
arthroplasty can theoretically provide a long-lasting biological
interface with the host bone. The objective of this study was to
test this hypothesis with propriety hydroxyapatite, peri-apatite,
coated tibial components using component migration measured with radiostereometric
analysis over two years as an indicator of long-term fixation. A total of 29 patients at two centres received uncemented PA-coated
tibial components and were followed for two years with radiostereometric
analysis exams to quantify the migration of the component.Aims
Patients and Methods
This study sought to establish the prevalence of the cross over
sign (COS) and posterior wall sign (PWS) in relation to the anterior
pelvic plane (APP) in an asymptomatic population through reliable
and accurate 3D-CT based assessment. Data from pelvic CT scans of 100 asymptomatic subjects (200 hips)
undertaken for conditions unrelated to disorders of the hip were
available for analysis in this study. A previously established 3D
analysis method was applied to assess the prevalence of the COS
and PWS in relation to the APP.Aims
Materials and Methods
The determination of the volumetric polyethylene wear on explanted material requires complicated equipment, which is not available in many research institutions. Our aim in this study was to present and validate a method that only requires a set of polyetheretherketone balls and a laboratory balance to determine wear. The insert to be measured was placed on a balance, and a ball of the appropriate diameter was inserted. The cavity remaining between the ball and insert caused by wear was filled with contrast medium and the weight of the contrast medium was recorded. The volume was calculated from the known density of the liquid. The precision, inter- and intraobserver reliability, were determined by four investigators on four days using nine inserts with specified wear (0.094 ml to 1.626 ml), and the intra-class correlation coefficient was calculated. The feasibility of using this method in routine clinical practice and the time required for measurement were tested on 84 explanted inserts by one investigator.Objectives
Methods
The stability of cementless acetabular components is an important
factor for surgical planning in the treatment of patients with pelvic
osteolysis after total hip arthroplasty (THA). However, the methods
for determining the stability of the acetabular component from pre-operative
radiographs remain controversial. Our aim was to develop a scoring
system to help in the assessment of the stability of the acetabular
component under these circumstances. The new scoring system is based on the mechanism of failure of
these components and the location of the osteolytic lesion, according
to the DeLee and Charnley classification. Each zone is evaluated
and scored separately. The sum of the individual scores from the
three zones is reported as a total score with a maximum of 10 points.
The study involved 96 revision procedures which were undertaken
for wear or osteolysis in 91 patients between July 2002 and December
2012. Pre-operative anteroposterior pelvic radiographs and Judet
views were reviewed. The stability of the acetabular component was
confirmed intra-operatively.Aims
Patients and Methods
Lumbar fusion is known to reduce the variation in pelvic tilt
between standing and sitting. A flexible lumbo-pelvic unit increases
the stability of total hip arthroplasty (THA) when seated by increasing
anterior clearance and acetabular anteversion, thereby preventing
impingement of the prosthesis. Lumbar fusion may eliminate this protective
pelvic movement. The effect of lumbar fusion on the stability of
total hip arthroplasty has not previously been investigated. The Medicare database was searched for patients who had undergone
THA and spinal fusion between 2005 and 2012. PearlDiver software
was used to query the database by the International Classification
of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedural
code for primary THA and lumbar spinal fusion. Patients who had
undergone both lumbar fusion and THA were then divided into three
groups: 1 to 2 levels, 3 to 7 levels and 8+ levels of fusion. The
rate of dislocation in each group was established using ICD-9-CM codes.
Patients who underwent THA without spinal fusion were used as a
control group. Statistical significant difference between groups
was tested using the chi-squared test, and significance set at p
<
0.05.Aims
Patients and Methods
What represents clinically significant acetabular undercoverage
in patients with symptomatic cam-type femoroacetabular impingement
(FAI) remains controversial. The aim of this study was to examine
the influence of the degree of acetabular coverage on the functional
outcome of patients treated arthroscopically for cam-type FAI. Between October 2005 and June 2016, 88 patients (97 hips) underwent
arthroscopic cam resection and concomitant labral debridement and/or
refixation. There were 57 male and 31 female patients with a mean
age of 31.0 years (17.0 to 48.5) and a mean body mass index (BMI)
of 25.4 kg/m2 (18.9 to 34.9). We used the Hip2Norm, an
object-oriented-platform program, to perform 3D analysis of hip
joint morphology using 2D anteroposterior pelvic radiographs. The lateral
centre-edge angle, anterior coverage, posterior coverage, total
femoral coverage, and alpha angle were measured for each hip. The
presence or absence of crossover sign, posterior wall sign, and
the value of acetabular retroversion index were identified automatically
by Hip2Norm. Patient-reported outcome scores were collected preoperatively
and at final follow-up with the Hip Disability and Osteoarthritis
Outcome Score (HOOS).Aims
Patients and Methods
The ability to determine human bone stiffness is of clinical relevance in many fields, including bone quality assessment and orthopaedic prosthesis design. Stiffness can be measured using compression testing, an experimental technique commonly used to test bone specimens A keyword search of all English language articles up until December 2017 of compression testing of bone was undertaken in Medline, Embase, PubMed, and Scopus databases. Studies using bulk tissue, animal tissue, whole bone, or testing techniques other than compression testing were excluded.Objectives
Methods
A total of 30 patients with thoracolumbar/lumbar adolescent idiopathic
scoliosis (AIS) treated between 1989 and 2000 with anterior correction
and fusion surgery using dual-rod instrumentation were reviewed. Radiographic parameters and clinical outcomes were compared among
patients with lowest instrumented vertebra (LIV) at the lower end
vertebra (LEV; EV group) (n = 13) and those treated by short fusion
(S group), with LIV one level proximal to EV (n = 17 patients). Aims
Patients and Methods
The aim of this study was to evaluate the correlation between
Salter’s criteria and Kalamchi’s classification of avascular necrosis
in patients treated for developmental dysphasia of the hip (DDH). The study involved a retrospective analysis of 123 patients (123
hips) with DDH treated by operative and non-operative reduction
before the age of two years, with a minimum follow-up of ten years.
Salter’s criteria (S1 to S4) were determined from radiographs obtained
at one to two years post-reduction, whilst the Kalamchi grade was determined
from radiographs obtained at ten or more years of age. Early post-reduction
radiographs were also used to evaluate the centre-head distance
discrepancy (CHDD) and the occurrence of a dome-shaped deformity
of the proximal femoral metaphysis (D-shaped metaphysis). The prognosis was described as good (Kalamchi grade K0 or KI),
fair (Kalamchi grade KII) or poor (Kalamchi grade KIII or KIV) for
analysis and correlation with the early Salter criteria, CHDD and
D-shaped metaphysis.Aims
Patients and Methods
The aim of this study was to present a series of patients with
aseptic failure of a total ankle arthroplasty (TAA) who were treated
with fusion of the hindfoot using a nail. A total of 23 TAAs, in 22 patients, were revised for aseptic
loosening and balloon osteolysis to a hindfoot fusion by a single
surgeon (NH) between January 2012 and August 2014. The procedure
was carried out without bone graft using the Phoenix, Biomet Hindfoot
Arthrodesis Nail. Preoperative investigations included full blood
count, CRP and ESR, and radiological investigations including plain
radiographs and CT scans. Postoperative plain radiographs were assessed
for fusion. When there was any doubt, CT scans were performed.Aims
Patients and Methods