MicroRNAs (miRNAs ) are small non-coding RNAs
that regulate gene expression. We hypothesised that the functions
of certain miRNAs and changes to their patterns of expression may
be crucial in the pathogenesis of nonunion. Healing fractures and
atrophic nonunions produced by periosteal cauterisation were created
in the femora of 94 rats, with 1:1 group allocation. At post-fracture
days three, seven, ten, 14, 21 and 28, miRNAs were extracted from
the newly generated tissue at the fracture site. Microarray and
real-time polymerase chain reaction (PCR) analyses of day 14 samples
revealed that five miRNAs, miR-31a-3p, miR-31a-5p, miR-146a-5p,
miR-146b-5p and miR-223-3p, were highly upregulated in nonunion.
Real-time PCR analysis further revealed that, in nonunion, the expression
levels of all five of these miRNAs peaked on day 14 and declined
thereafter. Our results suggest that miR-31a-3p, miR-31a-5p, miR-146a-5p,
miR-146b-5p and miR-223-3p may play an important role in the development
of nonunion. These findings add to the understanding of the molecular mechanism
for nonunion formation and may lead to the development of novel
therapeutic strategies for its treatment. Cite this article:
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:
The December 2015 Children’s orthopaedics Roundup360 looks at: Paediatric femoral fractures: a single incision nailing?; Lateral condylar fractures: open or percutaneous?; Forearm refracture: the risks; Tibial spine fractures; The child’s knee in MRI; The mechanics of SUFE; Idiopathic clubfoot
Elastic stable intramedullary nailing (ESIN)
is generally acknowledged to be the treatment of choice for displaced diaphyseal
femoral fractures in children over the age of three years, although
complication rates of up to 50% are described. Pre-bending the nails
is recommended, but there are no published data to support this.
Using synthetic bones and a standardised simulated fracture, we
performed biomechanical testing to determine the influence on the
stability of the fracture of pre-bending the nails before implantation.
Standard ESIN was performed on 24 synthetic femoral models with
a spiral fracture. In eight cases the nails were inserted without
any pre-bending, in a further eight cases they were pre-bent to
30° and in the last group of eight cases they were pre-bent to 60°. Mechanical
testing revealed that pre-bending to 60° produced a significant
increase in the stiffness or stability of the fracture. Pre-bending
to 60° showed a significant positive influence on the stiffness
compared with unbent nails. Pre-bending to 30° improved stiffness
only slightly. These findings validate the recommendations for pre-bending,
but the degree of pre-bend should exceed 30°. Adopting higher degrees
of pre-bending should improve stability in spiral fractures and
reduce the complications of varus deformity and shortening.
We report our experience of performing an elbow
hemiarthroplasty in the treatment of comminuted distal humeral fractures
in the elderly patients. A cohort of 42 patients (three men and 39 women, mean age 72;
56 to 84) were reviewed at a mean of 34.3 months (24 to 61) after
surgery. Functional outcome was measured with the Mayo Elbow Performance
Score (MEPS) and range of movement. The disabilities of the arm,
shoulder and hand questionnaire (DASH) was used as a patient rated
evaluation. Complications and ulnar nerve function were recorded.
Plain radiographs were obtained to assess prosthetic loosening,
olecranon wear and heterotopic bone formation. The mean extension deficit was 23.5° (0° to 60°) and mean flexion
was 126.8° (90° to 145°) giving a mean arc of 105.5° (60° to 145°).
The mean MEPS was 90 (50 to 100) and a mean DASH score of 20 (0
to 63). Four patients had additional surgery for limited range of
movement and one for partial instability. One elbow was revised
due to loosening, two patients had sensory ulnar nerve symptoms,
and radiographic signs of mild olecranon wear was noted in five
patients. Elbow hemiarthroplasty for comminuted intra-articular distal
humeral fractures produces reliable medium-term results with functional
outcome and complication rates, comparable with open reduction and
internal fixation and total elbow arthroplasty. Cite this article:
We prospectively assessed the diagnostic accuracy
of the gravity stress test and clinical findings to evaluate the stability
of the ankle mortise in patients with supination–external rotation-type
fractures of the lateral malleolus without widening of the medial
clear space. The cohort included 79 patients with a mean age of
44 years (16 to 82). Two surgeons assessed medial tenderness, swelling
and ecchymosis and performed the external rotation (ER) stress test
(a reference standard). A diagnostic radiographer performed the
gravity stress test. For the gravity stress test, the positive likelihood ratio (LR)
was 5.80 with a 95% confidence interval (CI) of 2.75 to 12.27, and
the negative LR was 0.15 (95% CI 0.07 to 0.35), suggesting a moderate
change from the pre-test probability. Medial tenderness, both alone
and in combination with swelling and/or ecchymosis, indicated a
small change (positive LR, 2.74 to 3.25; negative LR, 0.38 to 0.47),
whereas swelling and ecchymosis indicated only minimal changes (positive
LR, 1.41 to 1.65; negative LR, 0.38 to 0.47). In conclusion, when gravity stress test results are in agreement
with clinical findings, the result is likely to predict stability
of the ankle mortise with an accuracy equivalent to ER stress test
results. When clinical examination suggests a medial-side injury,
however, the gravity stress test may give a false negative result. Cite this article:
For over a decade, bisphosphonate administration
has evolved and become the cornerstone of the prevention and treatment
of fragility fractures. Millions of post-menopausal women have relied
on, and continue to depend on, the long-acting, bone density-maintaining
pharmaceutical drug to prevent low-energy fractures. In return,
we have seen the number of fragility fractures decrease, along with
associated costs and emotional benefits. However, with any drug,
there are often concerns with side effects and complications, and
this unique drug class is seeing one such complication in atypical
subtrochanteric femoral fracture, counterproductive to that which
it was designed to prevent. This has created concern over long-term
bisphosphonate administration and its potential link to these atypical
fractures. There is controversial evidence surrounding such a definitive
link, and no protocol for managing these fractures. This review offers the latest information regarding this rare
but increasingly controversial adverse effect and its potential
connection to one of the most successful forms of treatment that
is available for the management of fragility fractures.
End caps are intended to prevent nail migration
(push-out) in elastic stable intramedullary nailing. The aim of
this study was to investigate the force at failure with and without
end caps, and whether different insertion angles of nails and end caps
would alter that force at failure. Simulated oblique fractures of the diaphysis were created in
15 artificial paediatric femurs. Titanium Elastic Nails with end
caps were inserted at angles of 45°, 55° and 65° in five specimens
for each angle to create three study groups. Biomechanical testing
was performed with axial compression until failure. An identical
fracture was created in four small adult cadaveric femurs harvested
from two donors (both female, aged 81 and 85 years, height 149 cm and
156 cm, respectively). All femurs were tested without and subsequently
with end caps inserted at 45°. In the artificial femurs, maximum force was not significantly
different between the three groups (p = 0.613). Push-out force was
significantly higher in the cadaveric specimens with the use of
end caps by an up to sixfold load increase (830 N, standard deviation
(SD) 280 These results indicate that the nail and end cap insertion angle
can be varied within 20° without altering construct stability and
that the risk of elastic stable intramedullary nailing push–out
can be effectively reduced by the use of end caps. Cite this article:
The February 2015 Trauma Roundup360 looks at: Evaluating the syndesmosis in ankle fractures; Calcaneal fracture management an ongoing problem; Angular stable locking in low tibial fractures did not improve results; Open fractures: do the seconds really count?; Long-term outcomes of tibial fractures; Targeted performance improvements in pelvic fractures
Total knee arthroplasty (TKA) is known to lead
to a reduction in periprosthetic bone mineral density (BMD). In theory,
this may lead to migration, instability and aseptic loosening of
the prosthetic components. Bisphosphonates inhibit bone resorption
and may reduce this loss in BMD. We hypothesised that treatment
with bisphosphonates and calcium would lead to improved BMD and
clinical outcomes compared with treatment with calcium supplementation
alone following TKA. A total of 26 patients, (nine male and 17 female,
mean age 67 years) were prospectively randomised into two study
groups: alendronate and calcium (bisphosphonate group, n = 14) or calcium
only (control group, n = 12). Dual energy X-ray absorptiometry (DEXA)
measurements were performed post-operatively, and at three months,
six months, one, two, four, and seven years post-operatively. Mean femoral metaphyseal BMD was significantly higher in the
bisphosphonate group compared with controls, up to four years following
surgery in some areas of the femur (p = 0.045). BMD was observed
to increase in the lateral tibial metaphysis in the bisphosphonate
group until seven years (p = 0.002), and was significantly higher than
that observed in the control group throughout (p = 0.024). There
were no significant differences between the groups in the central
femoral metaphyseal, tibial medial metaphyseal or diaphyseal regions
of interest (ROI) of either the femur or tibia. Bisphosphonate treatment after TKA may be of benefit for patients
with poor bone quality. However, further studies with a larger number
of patients are necessary to assess whether this is clinically beneficial. Cite this article:
Between 1987 and 2006 we performed a modified Thompson’s quadricepsplasty on 40 fracture-related stiff knees and followed the patients for a mean of 7.9 years (2 to 11.1). The factors affecting the final gain of movement were investigated. A total of 15 knees required lengthening of the rectus femoris. The mean flexion gain was 70.2° (42.3° to 112.5°). According to Judet’s criteria, the results were excellent in 30 knees, good in seven, and fair in three. The range of movement which was achieved intra-operatively was related to the gain of knee flexion on univariate analysis. Five patients had complications: deep infection in one, recurrent patellar dislocation in one, and rupture of the extensor mechanism in three. This modified technique gives satisfactory results. Achieving maximum knee flexion intra-operatively seems to be the most important factor in enhancing the outcome in patients with stiffness of the knee following fracture.
