This article presents a unified clinical theory
that links established facts about the physiology of bone and homeostasis,
with those involved in the healing of fractures and the development
of nonunion. The key to this theory is the concept that the tissue
that forms in and around a fracture should be considered a specific
functional entity. This ‘bone-healing unit’ produces a physiological
response to its biological and mechanical environment, which leads
to the normal healing of bone. This tissue responds to mechanical
forces and functions according to Wolff’s law, Perren’s strain theory
and Frost’s concept of the “mechanostat”. In response to the local
mechanical environment, the bone-healing unit normally changes with
time, producing different tissues that can tolerate various levels
of strain. The normal result is the formation of bone that bridges
the fracture – healing by callus. Nonunion occurs when the bone-healing
unit fails either due to mechanical or biological problems or a
combination of both. In clinical practice, the majority of nonunions
are due to mechanical problems with instability, resulting in too
much strain at the fracture site. In most nonunions, there is an
intact bone-healing unit. We suggest that this maintains its biological
potential to heal, but fails to function due to the mechanical conditions.
The theory predicts the healing pattern of multifragmentary fractures
and the observed morphological characteristics of different nonunions.
It suggests that the majority of nonunions will heal if the correct
mechanical environment is produced by surgery, without the need
for biological adjuncts such as autologous bone graft. Cite this article:
Compression and absolute stability are important in the management of intra-articular fractures. We compared tension band wiring with plate fixation for the treatment of fractures of the olecranon by measuring compression within the fracture. Identical transverse fractures were created in models of the ulna. Tension band wires were applied to ten fractures and ten were fixed with Acumed plates. Compression was measured using a Tekscan force transducer within the fracture gap. Dynamic testing was carried out by reproducing cyclical contraction of the triceps of 20 N and of the brachialis of 10 N. Both methods were tested on each sample. Paired The mean compression for plating was 819 N ( During simulated movements, the mean compression was reduced in both groups, with tension band wiring at −14 N ( Pre-contoured plates provide significantly greater compression than tension bands in the treatment of transverse fractures of the olecranon, both over the whole fracture and specifically at the articular side of the fracture. In tension band wiring the overall compression was reduced and articular compression remained negligible during simulated contraction of the triceps, challenging the tension band principle.
We describe the impact of a targeted performance
improvement programme and the associated performance improvement
interventions, on mortality rates, error rates and process of care
for haemodynamically unstable patients with pelvic fractures. Clinical
care and performance improvement data for 185 adult patients with exsanguinating
pelvic trauma presenting to a United Kingdom Major Trauma Centre
between January 2007 and January 2011 were analysed with univariate
and multivariate regression and compared with National data. In
total 62 patients (34%) died from their injuries and opportunities
for improved care were identified in one third of deaths. Three major interventions were introduced during the study period
in response to the findings. These were a massive haemorrhage protocol,
a decision-making algorithm and employment of specialist pelvic
orthopaedic surgeons. Interventions which improved performance were
associated with an annual reduction in mortality (odds ratio 0.64
(95% confidence interval (CI) 0.44 to 0.93), p = 0.02), a reduction
in error rates (p = 0.024) and significant improvements in the targeted
processes of care. Exsanguinating patients with pelvic trauma are
complex to manage and are associated with high mortality rates;
implementation of a targeted performance improvement programme achieved
sustained improvements in mortality, error rates and trauma care
in this group of severely injured patients. Cite this article:
