Previously, we showed that case-specific non-linear
finite element (FE) models are better at predicting the load to failure
of metastatic femora than experienced clinicians. In this study
we improved our FE modelling and increased the number of femora
and characteristics of the lesions. We retested the robustness of
the FE predictions and assessed why clinicians have difficulty in
estimating the load to failure of metastatic femora. A total of
20 femora with and without artificial metastases were mechanically
loaded until failure. These experiments were simulated using case-specific
FE models. Six clinicians ranked the femora on load to failure and
reported their ranking strategies. The experimental load to failure
for intact and metastatic femora was well predicted by the FE models (R. 2. =
0.90 and R. 2. = 0.93, respectively). Ranking metastatic
femora on load to failure was well performed by the FE models (τ =
0.87), but not by the clinicians (0.11 <
τ <
0.42). Both the
FE models and the clinicians allowed for the characteristics of
the lesions, but only the FE models incorporated the initial bone
strength, which is essential for accurately predicting the risk
of
The use of plate-and-cable constructs to treat periprosthetic
We retrospectively reviewed 60
Prospective data on 6905 consecutive hip fracture
patients at a district general hospital were analysed to identify the
risk factors for the development of deep infection post-operatively.
The main outcome measure was infection beneath the fascia lata. A total of 50 patients (0.7%) had deep infection. Operations
by consultants or a specialist hip
Periprosthetic
Aims. A
Objectives. 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. Methods. 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. Results. The method of loading was found to affect the gap stiffness strongly (by up to six times) but also the magnitude of the plate stress and the location and magnitude of strains at the bone-screw interface. Conclusions. This study demonstrates that the method of loading is responsible for much of the difference in reported stiffness values in the literature. It also shows that previous contradictory findings, such as the influence of working length and very large differences in failure loads, can be readily explained by the choice of loading condition. Cite this article: A. MacLeod, A. H. R. W. Simpson, P. Pankaj. Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate
Objectives. To determine the morbidity and mortality outcomes of patients
presenting with a
A single antegrade Rush nail was used to treat 37
In a prospective study between August 2002 and August 2005, we studied the quantitative clinical and radiological outcome 36 months after percutaneous vertebroplasty for intractable type-II osteoporotic vertebral compression
Osteoporosis and fragility
Failed internal fixation of a
Immobility has been used as an indication for conservative treatment of patients with
Our aim was to investigate whether nitric oxide synthase (NOS) isoforms, responsible for the generation of NO, are expressed during the healing of
To determine the relative risk of complications in treating ankle
The management of radial nerve palsy associated with
The aim of this study was to determine the effect
of a Galeazzi
The aim of this randomised controlled study was
to compare functional and radiological outcomes between modern cemented
and uncemented hydroxyapatite coated stems after one year in patients
treated surgically for a
We have compared the outcomes of the use of external fixation devices for spanning or sparing the ankle joint in the treatment of
We describe the results of treatment of open