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:
Antegrade nailing of proximal humeral fractures
using a straight nail can damage the bony insertion of the supraspinatus
tendon and may lead to varus failure of the construct. In order
to establish the ideal anatomical landmarks for insertion of the
nail and their clinical relevance we analysed CT scans of bilateral
proximal humeri in 200 patients (mean age 45.1 years ( We therefore emphasise the need for ‘fastidious’ pre-operative
planning to minimise this risk. Cite this article:
Coronal plane fractures of the posterior femoral
condyle, also known as Hoffa fractures, are rare. Lateral fractures are
three times more common than medial fractures, although the reason
for this is not clear. The exact mechanism of injury is likely to
be a vertical shear force on the posterior femoral condyle with
varying degrees of knee flexion. These fractures are commonly associated
with high-energy trauma and are a diagnostic and surgical challenge. Hoffa
fractures are often associated with inter- or supracondylar distal
femoral fractures and CT scans are useful in delineating the coronal
shear component, which can easily be missed. There are few recommendations
in the literature regarding the surgical approach and methods of
fixation that may be used for this injury. Non-operative treatment
has been associated with poor outcomes. The goals of treatment are
anatomical reduction of the articular surface with rigid, stable
fixation to allow early mobilisation in order to restore function.
A surgical approach that allows access to the posterior aspect of
the femoral condyle is described and the use of postero-anterior
lag screws with or without an additional buttress plate for fixation
of these difficult fractures. Cite this article:
