This edition of Cochrane Corner looks at some of the work published by the Cochrane Collaboration, covering pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip,
Objectives. We have previously investigated an association between the genome copy number variation (CNV) and acetabular dysplasia (AD). Hip osteoarthritis is associated with a genetic polymorphism in the aspartic acid repeat in the N-terminal region of the asporin (ASPN) gene; therefore, the present study aimed to investigate whether the CNV of ASPN is involved in the pathogenesis of AD. Methods. Acetabular coverage of all subjects was evaluated using radiological findings (Sharp angle, centre-edge (CE) angle, acetabular roof obliquity (ARO) angle, and minimum joint space width). Genomic DNA was extracted from peripheral blood leukocytes. Agilent’s region-targeted high-density oligonucleotide tiling microarray was used to analyse 64 female AD patients and 32 female control subjects. All statistical analyses were performed using EZR software (Fisher’s exact probability test, Pearson’s correlation test, and Student’s t-test). Results. CNV analysis of the ASPN gene revealed a copy number loss in significantly more AD patients (9/64) than control subjects (0/32; p = 0.0212). This loss occurred within a 60 kb region on 9q22.31, which harbours the gene for ASPN. The mean radiological parameters of these AD patients were significantly worse than those of the other subjects (Sharp angle, p = 0.0056; CE angle, p = 0.0076; ARO angle, p = 0.0065), and all nine patients required operative therapy such as total hip arthroplasty or
We evaluated the accuracy of augmented reality (AR)-based navigation assistance through simulation of bone tumours in a pig femur model. We developed an AR-based navigation system for bone tumour resection, which could be used on a tablet PC. To simulate a bone tumour in the pig femur, a cortical window was made in the diaphysis and bone cement was inserted. A total of 133 pig femurs were used and tumour resection was simulated with AR-assisted resection (164 resection in 82 femurs, half by an orthropaedic oncology expert and half by an orthopaedic resident) and resection with the conventional method (82 resection in 41 femurs). In the conventional group, resection was performed after measuring the distance from the edge of the condyle to the expected resection margin with a ruler as per routine clinical practice.Objectives
Methods
Excessive acetabular coverage is the most common cause of pincer-type
femoroacetabular impingement. To date, an association between acetabular
over-coverage and genetic variations has not been studied. In this
study we investigated the association between single nucleotide
polymorphisms (SNPs) of paralogous Homeobox (HOX)9 genes and acetabular
coverage in Japanese individuals to identify a possible genetic
variation associated with acetabular over-coverage. We investigated 19 total SNPs in the four HOX9 paralogs, then
focused in detail on seven of those located in the 3’ untranslated
region of Objectives
Methods
The clinical utility of routine cross sectional imaging of the
abdomen and pelvis in the screening and surveillance of patients
with primary soft-tissue sarcoma of the extremities for metastatic
disease is controversial, based on its questionable yield paired
with concerns regarding the risks of radiation exposure, cost, and
morbidity resulting from false positive findings. Through retrospective review of 140 patients of all ages (mean
53 years; 2 to 88) diagnosed with soft-tissue sarcoma of the extremity
with a mean follow-up of 33 months (0 to 291), we sought to determine
the overall incidence of isolated abdominopelvic metastases, their
temporal relationship to chest involvement, the rate of false positives, and
to identify disparate rates of metastases based on sarcoma subtype.Objectives
Methods
Reported rates of dislocation in hip hemiarthroplasty
(HA) for the treatment of intra-capsular fractures of the hip, range
between 1% and 10%. HA is frequently performed through a direct
lateral surgical approach. The aim of this study is to determine
the contribution of the anterior capsule to the stability of a cemented
HA through a direct lateral approach. A total of five whole-body cadavers were thawed at room temperature,
providing ten hip joints for investigation. A Thompson HA was cemented
in place via a direct lateral approach. The cadavers were then positioned
supine, both knee joints were disarticulated and a digital torque
wrench was attached to the femur using a circular frame with three
half pins. The wrench applied an external rotation force with the
hip in extension to allow the hip to dislocate anteriorly. Each
hip was dislocated twice; once with a capsular repair and once without
repairing the capsule. Stratified sampling ensured the order in
which this was performed was alternated for the paired hips on each
cadaver. Comparing peak torque force in hips with the capsule repaired
and peak torque force in hips without repair of the capsule, revealed
a significant difference between the ‘capsule repaired’ (mean 22.96
Nm, standard deviation ( Cite this article:
Acetabular component orientation in total hip arthroplasty (THA)
influences results. Intra-operatively, the natural arthritic acetabulum
is often used as a reference to position the acetabular component.
Detailed information regarding its orientation is therefore essential. The
aim of this study was to identify the acetabular inclination and
anteversion in arthritic hips. Acetabular inclination and anteversion in 65 symptomatic arthritic
hips requiring THA were measured using a computer navigation system.
All patients were Caucasian with primary osteoarthritis (29 men,
36 women). The mean age was 68 years (SD 8). Mean inclination was
50.5° (SD 7.8) in men and 52.1° (SD 6.7) in women. Mean anteversion
was 8.3° (SD 8.7) in men and 14.4° (SD 11.6) in women. Objectives
Methods
Acetabular retractors have been implicated in damage to the femoral
and obturator nerves during total hip replacement. The aim of this
study was to determine the anatomical relationship between retractor
placement and these nerves. A posterior approach to the hip was carried out in six fresh
cadaveric half pelves. Large Hohmann acetabular retractors were
placed anteriorly, over the acetabular lip, and inferiorly, and
their relationship to the femoral and obturator nerves was examined.Objectives
Methods
Objectives. An experimental piglet model induces avascular necrosis (AVN)
and deformation of the femoral head but its secondary effects on
the developing acetabulum have not been studied. The aim of this
study was to assess the development of secondary acetabular deformation
following femoral head ischemia. Methods. Intracapsular circumferential ligation at the base of the femoral
neck and sectioning of the ligamentum teres were performed in three
week old piglets. MRI was then used for qualitative and quantitative
studies of the acetabula in operated and non-operated hips in eight
piglets from 48 hours to eight weeks post-surgery. Specimen photographs and
histological sections of the acetabula were done at the end of the
study. . Results. The operated-side acetabula were wider, shallower and misshapen,
with flattened labral edges. At eight weeks, increased acetabular
cartilage thickness characterised the operated sides compared with
non-operated sides (p <
0.001, ANOVA). The mean acetabular width
on the operated side was increased (p = 0.015) while acetabular depth
was decreased anteriorly (p = 0.007) and posteriorly (p = 0.44).
The cartilage was thicker, with delayed acetabular bone formation,
and showed increased vascularisation with fibrosis laterally and
focal degenerative changes involving chondrocyte hypocellularity,
chondrocyte cloning, peripheral pannus formation and surface fibrillation. . Conclusions. We demonstrate that femoral head AVN in the young growing piglet
also induced, and was coupled with, secondary malformation in acetabular
shape affecting both articular and adjacent
In order to evaluate the relationship between acetabular and proximal femoral alignment in the initiation and evolution of osteoarthritis of the dysplastic hip, the acetabular and femoral angles were calculated geometrically from radiographs of 62 patients with pre-arthrosis and early osteoarthritis. The sum of the lateral opening angle of the acetabulum and the neck-shaft angle was defined as the lateral instability index (LII), and the sum of the anterior opening angle of the acetabulum and the anteversion angle of the femoral neck as the anterior instability index (AII). These two indices were compared in dysplastic and unaffected hips. A total of 22 unilateral hips with pre-arthrosis were followed for at least 15 years to determine whether the two indices were associated with the progression of osteoarthritis. The LII of the affected hips (197.4 (
We dissected 20 cadaver hips in order to investigate the anatomy and excursion of the trochanteric muscles in relation to the posterior approach for total hip replacement. String models of each muscle were created and their excursion measured while the femur was moved between its anatomical position and the dislocated position. The position of the hip was determined by computer navigation. In contrast to previous studies which showed a separate insertion of piriformis and obturator internus, our findings indicated that piriformis inserted onto the superior and anterior margins of the greater trochanter through a conjoint tendon with obturator internus, and had connections to gluteus medius posteriorly. Division of these connections allowed lateral mobilisation of gluteus medius with minimal retraction. Analysis of the excursion of these muscles revealed that positioning the thigh for preparation of the femur through this approach elongated piriformis to a maximum of 182%, obturator internus to 185% and obturator externus to 220% of their resting lengths, which are above the thresholds for rupture of these muscles. Our findings suggested that gluteus medius may be protected from overstretching by release of its connection with the conjoint tendon. In addition, failure to detach piriformis or the obturators during a posterior approach for total hip replacement could potentially produce damage to these muscles because of over-stretching, obturator externus being the most vulnerable.
In a study on ten fresh human cadavers we examined the change in the height of the intervertebral disc space, the angle of lordosis and the geometry of the facet joints after insertion of intervertebral total disc replacements. SB III Charité prostheses were inserted at L3-4, L4-5, and L5-S1. The changes studied were measured using computer navigation sofware applied to CT scans before and after instrumentation. After disc replacement the mean lumbar disc height was doubled (p <
0.001). The mean angle of lordosis and the facet joint space increased by a statistically significant extent (p <
0.005 and p = 0.006, respectively). By contrast, the mean facet joint overlap was significantly reduced (p <
0.001). Our study indicates that the increase in the intervertebral disc height after disc replacement changes the geometry at the facet joints. This may have clinical relevance.
The cortical strains on the femoral neck and proximal femur were measured before and after implantation of a resurfacing femoral component in 13 femurs from human cadavers. These were loaded into a hip simulator for single-leg stance and stair-climbing. After resurfacing, the mean tensile strain increased by 15% (95% confidence interval (CI) 6 to 24, p = 0.003) on the lateral femoral neck and the mean compressive strain increased by 11% (95% CI 5 to 17, p = 0.002) on the medial femoral neck during stimulation of single-leg stance. On the proximal femur the deformation pattern remained similar to that of the unoperated femurs. The small increase of strains in the neck area alone would probably not be sufficient to cause fracture of the neck However, with patient-related and surgical factors these strain changes may contribute to the risk of early periprosthetic fracture.
We have developed an animal model to examine the formation of heterotopic ossification using standardised muscular damage and implantation of a beta-tricalcium phosphate block into a hip capsulotomy wound in Wistar rats. The aim was to investigate how cells originating from drilled femoral canals and damaged muscles influence the formation of heterotopic bone. The femoral canal was either drilled or left untouched and a tricalcium phosphate block, immersed either in saline or a rhBMP-2 solution, was implanted. These implants were removed at three and 21 days after the operation and examined histologically, histomorphometrically and immunohistochemically. Bone formation was seen in all implants in rhBMP-2-immersed, whereas in those immersed in saline the process was minimal, irrespective of drilling of the femoral canals. Bone mineralisation was somewhat greater in the absence of drilling with a mean mineralised volume to mean total volume of 18.2% ( Our findings suggest that osteoinductive signalling is an early event in the formation of ectopic bone. If applicable to man the results indicate that careful tissue handling is more important than the prevention of the dissemination of bone cells in order to avoid heterotopic ossification.
The human acetabulofemoral joint is commonly modelled as a pure ball-and-socket joint, but there has been no quantitative assessment of this assumption in the literature. Our aim was to test the limits and validity of this hypothesis. We performed experiments on four adult cadavers. Cortical pins, each equipped with a marker cluster, were implanted in the pelvis and the femur. Movements were recorded using stereophotogrammetry while an operator rotated the cadaver’s acetabulofemoral joint, exploiting the widest possible range of movement. The functional consistency of the acetabulofemoral joint as a pure spherical joint was assessed by comparing the magnitude of the translations of the hip joint centre as obtained on cadavers, with the centre of rotation of two metal segments linked through a perfectly spherical hinge. The results showed that the radii of the spheres containing 95% of the positions of the estimated centres of rotation were separated by less than 1 mm for both the acetabulofemoral joint and the mechanical spherical hinge. Therefore, the acetabulofemoral joint can be modelled as a spherical joint within the considered range of movement (flexion/extension 20° to 70°; abduction/adduction 0° to 45°; internal/external rotation 0° to 30°).
We have evaluated in vitro the accuracy of percutaneous and ultrasound registration as measured in terms of errors in rotation and version relative to the bony anterior