The modified Radiological Union Scale for Tibia (mRUST) fractures score was developed in order to assess progress to union and define a numerical assessment of fracture healing of metadiaphyseal fractures. This score has been shown to be valuable in predicting radiological union; however, there is no information on the sensitivity, specificity, and accuracy of this index for various cut-off scores. The aim of this study is to evaluate sensitivity, specificity, accuracy, and cut-off points of the mRUST score for the diagnosis of metadiaphyseal fractures healing. A cohort of 146 distal femur fractures were retrospectively identified at our institution. After excluding AO/OTA type B fractures, nonunions, follow-up less than 12 weeks, and patients aged less than 16 years, 104 sets of radiographs were included for analysis. Anteroposterior and lateral femur radiographs at six weeks, 12 weeks, 24 weeks, and final follow-up were separately scored by three surgeons using the mRUST score. The sensitivity and specificity of mean mRUST score were calculated using clinical and further radiological findings as a gold standard for ultimate fracture healing. A receiver operating characteristic curve was also performed to determine the cut-off points at each time point.Aims
Methods
The aim of this study was to determine the immediate post-fixation stability of a distal tibial fracture fixed with an intramedullary nail using a biomechanical model. This was used as a surrogate for immediate weight-bearing postoperatively. The goal was to help inform postoperative protocols. A biomechanical model of distal metaphyseal tibial fractures was created using a fourth-generation composite bone model. Three fracture patterns were tested: spiral, oblique, and multifragmented. Each fracture extended to within 4 cm to 5 cm of the plafond. The models were nearly-anatomically reduced and stabilized with an intramedullary nail and three distal locking screws. Cyclic loading was performed to simulate normal gait. Loading was completed in compression at 3,000 N at 1 Hz for a total of 70,000 cycles. Displacement (shortening, coronal and sagittal angulation) was measured at regular intervals.Aims
Methods
The aim of this study was to investigate the effect of a posterior
malleolar fragment (PMF), with <
25% ankle joint surface, on
pressure distribution and joint-stability. There is still little
scientific evidence available to advise on the size of PMF, which
is essential to provide treatment. To date, studies show inconsistent
results and recommendations for surgical treatment date from 1940. A total of 12 cadaveric ankles were assigned to two study groups.
A trimalleolar fracture was created, followed by open reduction
and internal fixation. PMF was fixed in Group I, but not in Group
II. Intra-articular pressure was measured and cyclic loading was
performed.Aims
Materials and Methods
It is becoming increasingly common for a patient
to have ipsilateral hip and knee replacements. The inter-prosthetic (IP)
distance, the distance between the tips of hip and knee prostheses,
has been thought to be associated with an increased risk of IP fracture.
Small gap distances are generally assumed to act as stress risers,
although there is no real biomechanical evidence to support this. The purpose of this study was to evaluate the influence of IP
distance, cortical thickness and bone mineral density on the likelihood
of an IP femoral fracture. A total of 18 human femur specimens were randomised into three
groups by bone density and cortical thickness. For each group, a
defined IP distance of 35 mm, 80 mm or 160 mm was created by choosing
the appropriate lengths of component. The maximum fracture strength
was determined using a four-point bending test. The fracture force of all three groups was similar (p = 0.498).
There was a highly significant correlation between the cortical
area and the fracture strength (r = 0.804, p <
0.001), whereas
bone density showed no influence. This study suggests that the IP distance has little influence
on fracture strength in IP femoral fractures: the thickness of the
cortex seems to be the decisive factor. Cite this article:
We investigated a new intramedullary locking
nail that allows the distal interlocking screws to be locked to
the nail. We compared fixation using this new implant with fixation
using either a conventional nail or a locking plate in a laboratory
simulation of an osteoporotic fracture of the distal femur. A total
of 15 human cadaver femora were used to simulate an AO 33-A3 fracture
pattern. Paired specimens compared fixation using either a locking
or non-locking retrograde nail, and using either a locking retrograde
nail or a locking plate. The constructs underwent cyclical loading
to simulate single-leg stance up to 125 000 cycles. Axial and torsional
stiffness and displacement, cycles to failure and modes of failure
were recorded for each specimen. When compared with locking plate
constructs, locking nail constructs had significantly longer mean
fatigue life (75 800 cycles ( The new locking retrograde femoral nail showed better stiffness
and fatigue life than locking plates, and superior fatigue life
to non-locking nails, which may be advantageous in elderly patients. Cite this article:
One commonly used rat fracture model for bone and mineral research
is a closed mid-shaft femur fracture as described by Bonnarens in
1984. Initially, this model was believed to create very reproducible
fractures. However, there have been frequent reports of comminution
and varying rates of complication. Given the importance of precise
anticipation of those characteristics in laboratory research, we
aimed to precisely estimate the rate of comminution, its importance and
its effect on the amount of soft callus created. Furthermore, we
aimed to precisely report the rate of complications such as death
and infection. We tested a rat model of femoral fracture on 84 rats based on
Bonnarens’ original description. We used a proximal approach with
trochanterotomy to insert the pin, a drop tower to create the fracture
and a high-resolution fluoroscopic imager to detect the comminution.
We weighed the soft callus on day seven and compared the soft callus
parameters with the comminution status.Objectives
Methods
Osteochondral injuries, if not treated adequately, often lead
to severe osteoarthritis. Possible treatment options include refixation
of the fragment or replacement therapies such as Pridie drilling,
microfracture or osteochondral grafts, all of which have certain
disadvantages. Only refixation of the fragment can produce a smooth
and resilient joint surface. The aim of this study was the evaluation
of an ultrasound-activated bioresorbable pin for the refixation of
osteochondral fragments under physiological conditions. In 16 Merino sheep, specific osteochondral fragments of the medial
femoral condyle were produced and refixed with one of conventional
bioresorbable pins, titanium screws or ultrasound-activated pins.
Macro- and microscopic scoring was undertaken after three months. Objectives
Methods
The surgical treatment of three- and four-part fractures of the proximal humerus in osteoporotic bone is difficult and there is no consensus as to which technique leads to the best outcome in elderly patients. Between 1998 and 2004 we treated 76 patients aged over 70 years with three- or four-part fractures by percutaneous reduction and internal fixation using the Humerusblock. A displacement of the tuberosity of >
5 mm and an angulation of >
30° of the head fragment were the indications for surgery. Of the patients 50 (51 fractures) were available for follow-up after a mean of 33.8 months (5.8 to 81). The absolute, age-related and side-related Constant scores were recorded. Of the 51 fractures, 46 (90.2%) healed primarily. Re-displacement of fragments or migration of Kirschner wires was seen in five cases. Necrosis of the humeral head developed in four patients. In three patients a secondary arthroplasty had to be performed, in two because of re-displacement and in one for necrosis of the head. There was one case of deep infection which required a further operation and one of delayed healing. The mean Constant score of the patients with a three-part fracture was 61.2 points (35 to 87) which was 84.9% of the score for the non-injured arm. In four-part fractures it was 49.5 points (18 to 87) or 68.5% of the score for the non-injured arm. The Humerusblock technique can provide a comfortable and mobile shoulder in elderly patients and is a satisfactory alternative to replacement and traditional techniques of internal fixation.
