Lumbar spondylolysis is a stress fracture of the pars interarticularis. We have evaluated the site of origin of the fracture clinically and biomechanically. Ten adolescents with incomplete stress fractures of the pars (four bilateral) were included in our study. There were seven boys and three girls aged between 11 and 17 years. The site of the fracture was confirmed by axial and sagittal reconstructed CT. The maximum principal tensile stresses and their locations in the L5 pars during lumbar movement were calculated using a three-dimensional finite-element model of the L3-S1 segment. In all ten patients the fracture line was seen only at the caudal-ventral aspect of the pars and did not spread completely to the craniodorsal aspect. According to the finite-element analysis, the higher stresses were found at the caudal-ventral aspect in all loading modes. In extension, the stress was twofold higher in the ventral than in the dorsal aspect. Our radiological and biomechanical results were in agreement with our clinical observations.
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 (R2 =
0.90 and R2 = 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 fracture. Accurate prediction of the risk of fracture should
be made possible for clinicians by further developing FE models.
The April 2015 Oncology Roundup360 looks at: New hope for skull base tumours; Survival but at what cost?; Synovial sarcoma beginning to be cracked?; Wound complications facing soft-tissue sarcoma surgeons; Amputation may offer no survival benefit over reconstruction; Giant cell tumour in the longer term; Intralesional treatment comparable with excision in GCT of the radius?; Imaging prior to oncological referral; And finally…
There is no single standardised method of measuring
the orientation of the acetabular component on plain radiographs
after total hip arthroplasty. We assessed the reliability and accuracy
of three methods of assessing anteversion of the acetabular component
for 551 THAs using the PolyWare software and the methods of Liaw
et al, and of Woo and Morrey. All measurements of the three methods
had excellent intra- and inter-observer reliability. The values
of the PolyWare software, which determines version of the acetabular
component by edge detection were regarded as the reference standard.
Although the PolyWare software and the method of Liaw et al were similarly
precise, the method of Woo and Morrey was significantly less accurate
(p <
0.001). The method of Liaw et al seemed to be more accurate
than that of Woo and Morrey when compared with the measurements
using the PolyWare software. If the qualified lateral radiograph
was selected, anteversion measured using the method of Woo and Morrey
was considered to be relatively reliable. Cite this article:
Diastematomyelia is a rare congenital abnormality
of the spinal cord. This paper summarises more than 30 years’ experience
of treating this condition. Data were collected retrospectively
on 138 patients with diastematomyelia (34 males, 104 females) who
were treated at our hospital from May 1978 to April 2010. A total
of 106 patients had double dural
Talonavicular and subtalar joint fusion through
a medial incision (modified triple arthrodesis) has become an increasingly
popular technique for treating symptomatic flatfoot deformity caused
by posterior tibial tendon dysfunction. The purpose of this study was to look at its clinical and radiological
mid- to long-term outcomes, including the rates of recurrent flatfoot
deformity, nonunion and avascular necrosis of the dome of the talus. A total of 84 patients (96 feet) with a symptomatic rigid flatfoot
deformity caused by posterior tibial tendon dysfunction were treated
using a modified triple arthrodesis. The mean age of the patients
was 66 years (35 to 85) and the mean follow-up was 4.7 years (1 to 8.3).
Both clinical and radiological outcomes were analysed retrospectively. In 86 of the 95 feet (90.5%) for which radiographs were available,
there was no loss of correction at final follow-up. In all, 14 feet
(14.7%) needed secondary surgery, six for nonunion, two for avascular
necrosis, five for progression of the flatfoot deformity and tibiotalar
arthritis and one because of symptomatic overcorrection. The mean
American Orthopaedic Foot and Ankle Society Hindfoot score (AOFAS
score) at final follow-up was 67 (between 16 and 100) and the mean
visual analogue score for pain 2.4 points (between 0 and 10). In conclusion, modified triple arthrodesis provides reliable
correction of deformity and a good clinical outcome at mid- to long-term
follow-up, with nonunion as the most frequent complication. Avascular
necrosis of the talus is a rare but serious complication of this
technique. Cite this article:
Over a five-year period, adult patients with
marginal impaction of acetabular fractures were identified from
a registry of patients who underwent acetabular reconstruction in
two tertiary referral centres. Fractures were classified according
to the system of Judet and Letournel. A topographic classification
to describe the extent of articular impaction was used, dividing
the joint surface into superior, middle and inferior thirds. Demographic information,
hospitalisation and surgery-related complications, functional (EuroQol
5-D) and radiological outcome according to Matta’s criteria were
recorded and analysed. In all, 60 patients (57 men, three women)
with a mean age of 41 years (18 to 72) were available at a mean
follow-up of 48 months (24 to 206). The quality of the reduction
was ‘anatomical’ in 44 hips (73.3%) and ‘imperfect’ in 16 (26.7%).
The originally achieved anatomical reduction was lost in Univariate linear regression analysis of the functional outcome
showed that factors associated with worse pain were increasing age
and an inferior location of the impaction. Elevation of the articular
impaction leads to joint preservation with satisfactory overall
medium-term functional results, but secondary collapse is likely
to occur in some patients. Cite this article:
The April 2015 Trauma Roundup360 looks at: Negative presure wound therapy in open tibial fractures; Priority-driven approach to pelvic injuries; Early surgery essential in hip fracture management; Sheer fractures to the posteromedial plateau; Fasciotomy closure under the spotlight; Why do patients die from hip fracture?; Acetabular fractures down the line; Biomechanics of femoral neck fractures reviewed
Orientation of the acetabular component influences
wear, range of movement and the incidence of dislocation after total
hip replacement (THR). During surgery, such orientation is often
referenced to the anterior pelvic plane (APP), but APP inclination
relative to the coronal plane (pelvic tilt) varies substantially
between individuals. In contrast, the change in pelvic tilt from
supine to standing (dPT) is small for nearly all individuals. Therefore,
in THR performed with the patient supine and the patient’s coronal
plane parallel to the operating table, we propose that freehand placement
of the acetabular component placement is reliable and reflects standing
(functional) cup position. We examined this hypothesis in 56 hips
in 56 patients (19 men) with a mean age of 61 years (29 to 80) using
three-dimensional CT pelvic reconstructions and standing lateral
pelvic radiographs. We found a low variability of acetabular component
placement, with 46 implants (82%) placed within a combined range
of 30° to 50° inclination and 5° to 25° anteversion. Changing from
the supine to the standing position (analysed in 47 patients) was associated
with an anteversion change <
10° in 45 patients (96%). dPT was
<
10° in 41 patients (87%). In conclusion, supine THR appears
to provide reliable freehand acetabular component placement. In
most patients a small reclination of the pelvis going from supine
to standing causes a small increase in anteversion of the acetabular component Cite this article:
Ankle replacements have improved significantly since the first reported attempt at resurfacing of the talar dome in 1962. We are now at a stage where ankle replacement offers a viable option in the treatment of end-stage ankle arthritis. As the procedure becomes more successful, it is important to reflect and review the current surgical outcomes. This allows us to guide our patients in the treatment of end-stage ankle arthritis. What is the better surgical treatment – arthrodesis or replacement?
In this study we used subject-specific finite
element analysis to investigate the mechanical effects of rotational acetabular
osteotomy (RAO) on the hip joint and analysed the correlation between
various radiological measurements and mechanical stress in the hip
joint. We evaluated 13 hips in 12 patients (two men and ten women, mean
age at surgery 32.0 years; 19 to 46) with developmental dysplasia
of the hip (DDH) who were treated by RAO. Subject-specific finite element models were constructed from
CT data. The centre–edge (CE) angle, acetabular head index (AHI),
acetabular angle and acetabular roof angle (ARA) were measured on
anteroposterior pelvic radiographs taken before and after RAO. The
relationship between equivalent stress in the hip joint and radiological measurements
was analysed. The equivalent stress in the acetabulum decreased from 4.1 MPa
(2.7 to 6.5) pre-operatively to 2.8 MPa (1.8 to 3.6) post-operatively
(p <
0.01). There was a moderate correlation between equivalent
stress in the acetabulum and the radiological measurements: CE angle
(R = –0.645, p <
0.01); AHI (R = –0.603, p <
0.01); acetabular
angle (R = 0.484, p = 0.02); and ARA (R = 0.572, p <
0.01). The equivalent stress in the acetabulum of patients with DDH
decreased after RAO. Correction of the CE angle, AHI and ARA was
considered to be important in reducing the mechanical stress in
the hip joint. Cite this article:
Numerous complications following total knee replacement (TKR)
relate to the patellofemoral (PF) joint, including pain and patellar
maltracking, yet the options for A total of three knees with end-stage osteoarthritis and three
knees that had undergone TKR at more than one year’s follow-up were
investigated. In each knee, sequential biplane radiological images
were acquired from the sagittal direction (i.e. horizontal X-ray
source and 10° below horizontal) for a sequence of eight flexion
angles. Three-dimensional implant or bone models were matched to
the biplane images to compute the six degrees of freedom of PF tracking
and TF kinematics, and other clinical measures.Objectives
Methods
We determined the efficacy of a devitalised autograft
(n = 13) and allograft (n = 16) cortical strut bone graft combined
with long-stem endoprosthetic reconstruction in the treatment of
massive tumours of the lower limb. A total of 29 patients (18 men:11
women, mean age 20.1 years (12 to 45) with a ratio of length of
resection to that of the whole prosthesis of >
50% were treated
between May 2003 and May 2012. The mean follow-up was 47 months
(15 to 132). The stem of the prosthesis was introduced through bone
graft struts filled with cement, then cemented into the residual
bone. Bone healing was achieved in 23 patients (86%). The mean Musculoskeletal
Tumour Society functional score was 85% (57 to 97). The five-year
survival rate of the endoprostheses was 81% (95% confidence intervals
67.3 to 92.3). The mean length of devitalised autografts and allografts
was 8.6 cm (5 to 15), which increased the ratio of the the length
of the stem of the prosthesis to that of the whole length of the
prosthesis from a theoretical 35% to an actual 55%. Cortical strut bone grafting and long-stem endoprosthetic reconstruction
is an option for treating massive segmental defects following resection
of a tumour in the lower limb. Patients can regain good function
with a low incidence of aseptic loosening. The strut graft and the
residual bone together serve as a satisfactory bony environment
for a revision prosthesis, if required, once union is achieved. Cite this article:
Large-head metal-on-metal total hip replacement has a failure rate of almost 8% at five years, three times the revision rate of conventional hip replacement. Unexplained pain remains a feature of this type of arthroplasty. All designs of the femoral component of large-head metal-on-metal total hip replacements share a unique characteristic: a subtended angle of 120° defining the proportion of a sphere that the head represents. Using MRI, we measured the contact area of the iliopsoas tendon on the femoral head in sagittal reconstruction of 20 hips of patients with symptomatic femoroacetabular impingement. We also measured the articular extent of the femoral head on 40 normal hips and ten with cam-type deformities. Finally, we performed virtual hip resurfacing on normal and cam-type hips, avoiding overhang of the metal rim inferomedially. The articular surface of the femoral head has a subtended angle of 120° anteriorly and posteriorly, but only 100° medially. Virtual surgery in a normally shaped femoral head showed a 20° skirt of metal protruding medially where iliopsoas articulates. The excessive extent of the large-diameter femoral components may cause iliopsoas impingement independently of the acetabular component. This may be the cause of postoperative pain with these implants.
The February 2015 Shoulder &
Elbow Roundup360 looks at: Proximal Humerus fractures a comprehensive review, Predicting complications in shoulder ORIF, The Coronoid Revisited, Remplissage and bankart repair for Hill-Sach’s lesions, Diabetes and elbow arthroplasty, Salvage surgery for failed bankart repair, Sternoclavicular Joint Reconstruction, Steroids effective in the short-term for tennis elbow
This study examined spinal fractures in patients
admitted to a Major Trauma Centre via two independent pathways,
a major trauma (MT) pathway and a standard unscheduled non-major
trauma (NMT) pathway. A total of 134 patients were admitted with
a spinal fracture over a period of two years; 50% of patients were
MT and the remainder NMT. MT patients were predominantly male, had
a mean age of 48.8 years (13 to 95), commonly underwent surgery
(62.7%), characteristically had fractures in the cervico-thoracic
and thoracic regions and 50% had fractures of more than one vertebrae,
which were radiologically unstable in 70%. By contrast, NMT patients
showed an equal gender distribution, were older (mean 58.1 years;
12 to 94), required fewer operations (56.7%), characteristically
had fractures in the lumbar region and had fewer multiple and unstable
fractures. This level of complexity was reflected in the length
of stay in hospital; MT patients receiving surgery were in hospital
for a mean of three to four days longer than NMT patients. These
results show that MT patients differ from their NMT counterparts
and have an increasing complexity of spinal injury. Cite this article:
Guidelines for the management of patients with metastatic bone
disease (MBD) have been available to the orthopaedic community for
more than a decade, with little improvement in service provision
to this increasingly large patient group. Improvements in adjuvant
and neo-adjuvant treatments have increased both the number and overall
survival of patients living with MBD. As a consequence the incidence
of complications of MBD presenting to surgeons has increased and
is set to increase further. The British Orthopaedic Oncology Society
(BOOS) are to publish more revised detailed guidelines on what represents
‘best practice’ in managing patients with MBD. This article is designed
to coincide with and publicise new BOOS guidelines and once again
champion the cause of patients with MBD. A series of short cases highlight common errors frequently being
made in managing patients with MBD despite the availability of guidelines.Objectives
Methods
The December 2014 Foot &
Ankle Roundup360 looks at: Charcot feet, biomarkers and diabetes; weight bearing following Achilles tendon rupture; endobuttons and mal-reduced diastasis; evidence for stem cell therapies in osteochondral lesions of the talus; syndesmosis fixation in SER ankle fractures; and self-reporting for foot and ankle outcomes.
Both conservative and operative forms of treatment
have been recommended for patients with a ‘floating shoulder’. We
compared the results of conservative and operative treatment in
25 patients with this injury and investigated the use of the glenopolar
angle (GPA) as an indicator of the functional outcome. A total of
13 patients (ten male and three female; mean age 32.5 years (24.7
to 40.4)) were treated conservatively and 12 patients (ten male
and two female; mean age 33.67 years (24.6 to 42.7)) were treated
operatively by fixation of the clavicular fracture alone. Outcome
was assessed using the Herscovici score, which was also related
to changes in the GPA at one year post-operatively. The mean Herscovici score was significantly better three months
and two years after the injury in the operative group (p <
0.001
and p = 0.003, respectively). There was a negative correlation between
the change in GPA and the Herscovici score at two years follow-up
in both the conservative and operative groups, but neither were
statistically significant
(r = -0.295 and r = -0.19, respectively). There was a significant
difference between the pre- and post-operative GPA in the operative
group (p = 0.017). When compared with conservative treatment, fixation of the clavicle
alone gives better results in the treatment of patients with a floating
shoulder. The GPA changes significantly with fixation of clavicle
alone but there is no significant correlation between the pre-injury
GPA and the final clinical outcome in these patients. Cite this article:
Unstable pelvic injuries in young children with
an immature pelvis have different modes of failure from those in adolescents
and adults. We describe the pathoanatomy of unstable pelvic injuries
in these children, and the incidence of associated avulsion of the
iliac apophysis and fracture of the ipsilateral fifth lumbar transverse
process (L5-TP). We retrospectively reviewed the medical records
of 33 children with Tile types B and C pelvic injuries admitted
between 2007 and 2014; their mean age was 12.6 years (2 to 18) and
12 had an immature pelvis. Those with an immature pelvis commonly
sustained symphyseal injuries anteriorly with diastasis, rather
than the fractures of the pubic rami seen in adolescents. Posteriorly,
transsacral fractures were more commonly encountered in mature children,
whereas sacroiliac dislocations and fracture-dislocations were seen
in both age groups. Avulsion of the iliac apophysis was identified
in eight children, all of whom had an immature pelvis with an intact
ipsilateral L5-TP. Young children with an immature pelvis are more
susceptible to pubic symphysis and sacroiliac diastasis, whereas
bony failures are more common in adolescents. Unstable pelvic injuries
in young children are commonly associated with avulsion of the iliac
apophysis, particularly with displaced SI joint dislocation and
an intact ipsilateral L5-TP. Cite this article: