Secondary fracture healing is strongly influenced by the stiffness of the bone-fixator system. Biomechanical tests are extensively used to investigate stiffness and strength of fixation devices. The stiffness values reported in the literature for locked plating, however, vary by three orders of magnitude. The aim of this study was to examine the influence that the method of restraint and load application has on the stiffness produced, the strain distribution within the bone, and the stresses in the implant for locking plate constructs. Synthetic composite bones were used to evaluate experimentally the influence of four different methods of loading and restraining specimens, all used in recent previous studies. Two plate types and three screw arrangements were also evaluated for each loading scenario. Computational models were also developed and validated using the experimental tests.Objectives
Methods
The aim of this study was to assess hypertrophy of the extra-articular
tendon of the long head of biceps (LHB) in patients with a rotator
cuff tear. The study involved 638 shoulders in 334 patients (175 men, 159
women, mean age 62.6 years; 25 to 81) with unilateral symptomatic
rotator cuff tears. The cross-sectional area (CSA) of the LHB tendon
in the bicipital groove was measured pre-operatively in both shoulders
using ultrasound. There were 154 asymptomatic rotator cuff tears
in the contralateral shoulder. Comparisons were made between those
with a symptomatic tear, an asymptomatic tear and those with no
rotator cuff tear. In the affected shoulders, the CSAs were compared
in relation to the location and size of the rotator cuff tear. Aims
Patients and Methods
Using 90% of final height as a benchmark, we sought to develop
a quick, quantitative and reproducible method of estimating skeletal
maturity based on topographical changes in the distal femoral physis. Serial radiographs of the distal femoral physis three years prior
to, during, and two years following the chronological age associated
with 90% of final height were analyzed in 81 healthy children. The
distance from the tip of the central peak of the distal femoral
physis to a line drawn across the physis was normalized to the physeal width.Aims
Patients and Methods
The objective of this study was to quantify the relative movement between the articular surfaces in the tibiotalar and subtalar joints during normal walking in asymptomatic individuals. 3D movement data of the ankle joint complex were acquired from 18 subjects using a biplanar fluoroscopic system and 3D-to-2D registration of bone models obtained from CT images. Surface relative velocity vectors (SRVVs) of the articular surfaces of the tibiotalar and subtalar joints were calculated. The relative movement of the articulating surfaces was quantified as the mean relative speed (RS) and synchronization index (SIENT) of the SRVVs.Objectives
Methods
This paper describes the methodology, validation and reliability
of a new computer-assisted method which uses models of the patient’s
bones and the components to measure their migration and polyethylene
wear from radiographs after total hip arthroplasty (THA). Models of the patient’s acetabular and femoral component obtained
from the manufacturer and models of the patient’s pelvis and femur
built from a single computed tomography (CT) scan, are used by a
computer program to measure the migration of the components and
the penetration of the femoral head from anteroposterior and lateral radiographs
taken at follow-up visits. The program simulates the radiographic
setup and matches the position and orientation of the models to
outlines of the pelvis, the acetabular and femoral component, and
femur on radiographs. Changes in position and orientation reflect
the migration of the components and the penetration of the femoral
head. Validation was performed using radiographs of phantoms simulating
known migration and penetration, and the clinical feasibility of
measuring migration was assessed in two patients.Aims
Materials and Methods
In recent years, the plantaris tendon has been
implicated in the development of chronic painful mid-portion Achilles tendinopathy.
In some cases, a thickened plantaris tendon is closely associated
with the Achilles tendon, and surgical excision of the plantaris
tendon has been reported to be curative in patients who have not
derived benefit following conservative treatment and surgical interventions. The aim of this review is to outline the basic aspects of, and
the recent research findings, related to the plantaris tendon, covering
anatomical and clinical studies including those dealing with histology,
imaging and treatment. Cite this article
The aim of this study was to report the mid-term clinical outcome
of cemented unlinked J-alumina ceramic elbow (JACE) arthroplasties
when used in patients with rheumatoid arthritis (RA). We retrospectively reviewed 87 elbows, in 75 patients with RA,
which was replaced using a cemented JACE total elbow arthroplasty
(TEA) between August 2003 and December 2012, with a follow-up of
96%. There were 72 women and three men, with a mean age of 62 years
(35 to 79). The mean follow-up was nine years (2 to 14). The clinical condition
of each elbow before and after surgery was assessed using the Mayo
Elbow Performance Index (MEPI, 0 to 100 points). Radiographic loosening
was defined as a progressive radiolucent line of >1 mm that was
completely circumferential around the prosthesis.Aims
Patients and Methods
In patients where the proximal femur shows gross deformity due
to degenerative changes or fracture, the contralateral femur is
often used to perform preoperative templating for hip arthroplasty.
However, femurs may not be symmetrical: the aim of this study was
to determine the degree of variation between hips in healthy individuals and
to determine whether it is affected by demographic parameters. CT-scan based modelling was used to examine the pelvis and bilateral
femurs of 345 patients (211 males, 134 women; mean age 62 years
(standard deviation (Aims
Materials and Methods
Unicompartmental knee arthroplasty (UKA) is a demanding procedure, with tibial component subsidence or pain from high tibial strain being potential causes of revision. The optimal position in terms of load transfer has not been documented for lateral UKA. Our aim was to determine the effect of tibial component position on proximal tibial strain. A total of 16 composite tibias were implanted with an Oxford Domed Lateral Partial Knee implant using cutting guides to define tibial slope and resection depth. Four implant positions were assessed: standard (5° posterior slope); 10° posterior slope; 5° reverse tibial slope; and 4 mm increased tibial resection. Using an electrodynamic axial-torsional materials testing machine (Instron 5565), a compressive load of 1.5 kN was applied at 60 N/s on a meniscal bearing via a matching femoral component. Tibial strain beneath the implant was measured using a calibrated Digital Image Correlation system.Objectives
Methods
The classical longitudinal incision used for the direct anterior
approach (DAA) to the hip does not follow the tension lines of the
skin and can lead to impaired wound healing and poor cosmesis. The
purpose of this retrospective study was to determine the satisfaction
with the scar, and functional and radiographic outcomes comparing
the classic longitudinal incision with a modified skin crease ‘bikini’
when the DAA is used for total hip arthroplasty (THA). A total of 964 patients (51% female; 59% longitudinal, 41% ‘bikini’)
completed a follow-up questionnaire between two and four years postoperatively,
including the Oxford Hip Score (OHS), the University of North Carolina
‘4P’ scar scale (UNC4P) and two items for assessing the aesthetic
appearance of the scar and symptoms of numbness. The positioning
of the components, rates of heterotopic ossification (HO) and rates
of revision were assessed.Aims
Patients and Methods
The posterior malleolus of the ankle is the object
of increasing attention, with considerable enthusiasm for CT scanning
and surgical fixation, as expressed in a recent annotation in Cite this article:
Positive ulnar variance is an established risk factor for idiopathic
ulnar impaction syndrome (UIS). However, not all patients with positive
ulnar variance develop symptomatic UIS and other factors, including
the morphology of the lunate, may be involved. The aim of this study
was to clarify the relationship between lunate morphology and idiopathic
UIS. A cohort of 95 patients with idiopathic UIS (UIS group) was compared
with 95 asymptomatic controls with positive ulnar variance. The
shape of the lunate was measured using the capitate-triquetrum distance
(CTD), ulnar coverage ratio (UCR), radiolunate distance and radiolunate
angle. The association of radiographic parameters and lunate types
with the development of UIS was investigated in univariable and
multivariable analyses. Receiver operating characteristic curves
were used to estimate a cutoff for any statistically significant
variables.Aims
Patients and Methods
In this prospective cohort study, we investigated whether patient-specific finite element (FE) models can identify patients at risk of a pathological femoral fracture resulting from metastatic bone disease, and compared these FE predictions with clinical assessments by experienced clinicians. A total of 39 patients with non-fractured femoral metastatic lesions who were irradiated for pain were included from three radiotherapy institutes. During follow-up, nine pathological fractures occurred in seven patients. Quantitative CT-based FE models were generated for all patients. Femoral failure load was calculated and compared between the fractured and non-fractured femurs. Due to inter-scanner differences, patients were analyzed separately for the three institutes. In addition, the FE-based predictions were compared with fracture risk assessments by experienced clinicians.Objectives
Methods
The aims of this study were: firstly, to investigate the influence
of the thickness of cartilage at the sigmoid notch on the inclination
of the distal radioulnar joint (DRUJ), and secondly, to compare
the sensitivity and specificity of MRI with plain radiographs for
the assessment of the inclination of the articular surface of the
DRUJ in the coronal plane. Contemporaneous MRI images and radiographs of 100 wrists from
98 asymptomatic patients (mean age 43 years, (16 to 67); 52 male,
53%) with no history of a fracture involving the wrist or surgery
to the wrist, were reviewed. The thickness of the cartilage at the
sigmoid notch, inclination of the DRUJ and Tolat Type of each DRUJ
were determined. Aims
Patients and Methods
To assess the effect of high tibial and distal femoral osteotomies
(HTO and DFO) on the pressure characteristics of the ankle joint. Varus and valgus malalignment of the knee was simulated in human
cadaver full-length legs. Testing included four measurements: baseline
malalignment, 5° and 10° re-aligning osteotomy, and control baseline
malalignment. For HTO, testing was rerun with the subtalar joint
fixed. In order to represent half body weight, a 300 N force was applied
onto the femoral head. Intra-articular sensors captured ankle pressure.Aims
Materials and Methods
