The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue. A total of 47 human labral specimens were obtained from a biobank. These included 22 torn specimens and 25 control specimens from patients undergoing total hip arthroplasty with macroscopically normal labra. The specimens underwent dynamic shear analysis using a rheometer to measure storage modulus, as an indicator of structural integrity.Objectives
Methods
Rotator cuff tears are among the most frequent upper extremity injuries. Current treatment strategies do not address the poor quality of the muscle and tendon following chronic rotator cuff tears. Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor that activates many genes that are important in skeletal muscle regeneration. HIF-1α is inhibited under normal physiological conditions by the HIF prolyl 4-hydroxylases (PHDs). In this study, we used a pharmacological PHD inhibitor, GSK1120360A, to enhance the activity of HIF-1α following the repair of a chronic cuff tear, and measured muscle fibre contractility, fibrosis, gene expression, and enthesis mechanics. Chronic supraspinatus tears were induced in adult rats, and repaired 28 days later. Rats received 0 mg/kg, 3 mg/kg, or 10 mg/kg GSK1120360A daily. Collagen content, contractility, fibre type distribution and size, the expression of genes involved in fibrosis, lipid accumulation, atrophy and inflammation, and the mechanical properties of the enthesis were then assessed two weeks following surgical repair.Objectives
Methods
External fixators are the traditional fixation method of choice for contaminated open fractures. However, patient acceptance is low due to the high profile and therefore physical burden of the constructs. An externalised locking compression plate is a low profile alternative. However, the biomechanical differences have not been assessed. The objective of this study was to evaluate the axial and torsional stiffness of the externalised titanium locking compression plate (ET-LCP), the externalised stainless steel locking compression plate (ESS-LCP) and the unilateral external fixator (UEF). A fracture gap model was created to simulate comminuted mid-shaft tibia fractures using synthetic composite bones. Fifteen constructs were stabilised with ET-LCP, ESS-LCP or UEF (five constructs each). The constructs were loaded under both axial and torsional directions to determine construct stiffness.Objectives
Methods
The aim of this paper is to review the evidence relating to the
anatomy of the proximal femur, the geometry of the fracture and
the characteristics of implants and methods of fixation of intertrochanteric
fractures of the hip. Relevant papers were identified from appropriate clinical databases
and a narrative review was undertaken.Aims
Materials and Methods
We investigated the effects on fracture healing of two up-regulators of inducible nitric oxide synthase (iNOS) in a rat model of an open femoral osteotomy: tadalafil, a phosphodiesterase inhibitor, and the recently reported nutraceutical, COMB-4 (consisting of L-citrulline, Paullinia cupana, ginger and muira puama), given orally for either 14 or 42 days. Unilateral femoral osteotomies were created in 58 male rats and fixed with an intramedullary compression nail. Rats were treated daily either with vehicle, tadalafil or COMB-4. Biomechanical testing of the healed fracture was performed on day 42. The volume, mineral content and bone density of the callus were measured by quantitative CT on days 14 and 42. Expression of iNOS was measured by immunohistochemistry.Objectives
Materials and Methods
Periprosthetic femoral fractures (PFF) following total hip arthroplasty
(THA) are devastating complications that are associated with functional
limitations and increased overall mortality. Although cementless
implants have been associated with an increased risk of PFF, the
precise contribution of implant geometry and design on the risk
of both intra-operative and post-operative PFF remains poorly investigated.
A systematic review was performed to aggregate all of the PFF literature
with specific attention to the femoral implant used. A systematic search strategy of several journal databases and
recent proceedings from the American Academy of Orthopaedic Surgeons
was performed. Clinical articles were included for analysis if sufficient
implant description was provided. All articles were reviewed by
two reviewers. A review of fundamental investigations of implant
load-to-failure was performed, with the intent of identifying similar
conclusions from the clinical and fundamental literature.Aims
Patients and Methods
The fundamental concept of open reduction and internal fixation
(ORIF) of ankle fractures has not changed appreciably since the
1960s and, whilst widely used, is associated with complications
including wound dehiscence and infection, prominent hardware and
failure. Closed reduction and intramedullary fixation (CRIF) using
a fibular nail, wires or screws is biomechanically stronger, requires
minimal incisions, and has low-profile hardware. We hypothesised
that fibular nailing in the elderly would have similar functional
outcomes to standard fixation, with a reduced rate of wound and
hardware problems. A total of 100 patients (25 men, 75 women) over the age of 65
years with unstable ankle fractures were randomised to undergo standard
ORIF or fibular nailing (11 men and 39 women in the ORIF group,
14 men and 36 women in the fibular nail group). The mean age was
74 years (65 to 93) and all patients had at least one medical comorbidity. Complications,
patient related outcome measures and cost-effectiveness were assessed
over 12 months.Aims
Patients and Methods
The purpose of this study was to compare the thickness of the hip capsule in patients with surgical hip disease, either with cam-femoroacetabular impingement (FAI) or non-FAI hip pathology, with that of asymptomatic control hips. A total of 56 hips in 55 patients underwent a 3Tesla MRI of the hip. These included 40 patients with 41 hips with arthroscopically proven hip disease (16 with cam-FAI; nine men, seven women; mean age 39 years, 22 to 58) and 25 with non-FAI chondrolabral pathology (four men, 21 women; mean age 40 years, 18 to 63) as well as 15 asymptomatic volunteers, whose hips served as controls (ten men, five women; mean age 62 years, 33 to 77). The maximal capsule thickness was measured anteriorly and superiorly, and compared within and between the three groups with a gender subanalysis using student’s Objectives
Methods
To compare radiographic failure and re-operation rates of anatomical
coracoclavicular (CC) ligament reconstructional techniques with
non-anatomical techniques after chronic high grade acromioclavicular
(AC) joint injuries. We reviewed chronic AC joint reconstructions within a region-wide
healthcare system to identify surgical technique, complications,
radiographic failure and re-operations. Procedures fell into four
categories: Aims
Patients and Methods
This animal study compares different methods
of performing an osteotomy, including using an Erbium-doped Yttrium
Aluminum Garnet laser, histologically, radiologically and biomechanically.
A total of 24 New Zealand rabbits were divided into four groups
(Group I: multihole-drilling; Group II: Gigli saw; Group III: electrical
saw blade and Group IV: laser). A proximal transverse diaphyseal
osteotomy was performed on the right tibias of the rabbits after the
application of a circular external fixator. The rabbits were killed
six weeks after the procedure, the operated tibias were resected
and radiographs taken. . The specimens were tested biomechanically using three-point bending
forces, and four tibias from each group were examined histologically.
Outcome parameters were the biomechanical stability of the tibias
as assessed by the
There is an increased risk of fracture following
osteoplasty of the femoral neck for cam-type femoroacetabular impingement
(FAI). Resection of up to 30% of the anterolateral head–neck junction
has previously been considered to be safe, however, iatrogenic fractures
have been reported with resections within these limits. We re-evaluated
the amount of safe resection at the anterolateral femoral head–neck
junction using a biomechanically consistent model. In total, 28 composite bones were studied in four groups: control,
10% resection, 20% resection and 30% resection. An axial load was
applied to the adducted and flexed femur. Peak load, deflection
at time of fracture and energy to fracture were assessed using comparison
groups. There was a marked difference in the mean peak load to fracture
between the control group and the 10% resection group (p <
0.001).
The control group also tolerated significantly more deflection before
failure (p <
0.04). The mean peak load (p = 0.172), deflection
(p = 0.547), and energy to fracture (p = 0.306) did not differ significantly between
the 10%, 20%, and 30% resection groups. Any resection of the anterolateral quadrant of the femoral head–neck
junction for FAI significantly reduces the load-bearing capacity
of the proximal femur. After initial resection of cortical bone,
there is no further relevant loss of stability regardless of the
amount of trabecular bone resected. Based on our findings we recommend any patients who undergo anterolateral
femoral head–neck junction osteoplasty should be advised to modify
their post-operative routine until cortical remodelling occurs to
minimise the subsequent fracture risk. Cite this article:
The April 2014 Wrist &
Hand Roundup360 looks at: diagnosis of compressive neuropathy; relevant reviews; the biomechanics of dorsal PIP fracture dislocation; the more strands the better; and state of mind the best predictor of outcome.
The April 2014 Hip & Pelvis Roundup360 looks at: Recent arthroplasty and flight; whether that squeak could be a fracture; diagnosing early infected hip replacement; impaction grafting at a decade; whether squeaking is more common than previously thought; femoral offset associated with post THR outcomes; and periprosthetic fracture stabilisation.
There remains conflicting evidence regarding cortical bone strength
following bisphosphonate therapy. As part of a study to assess the
effects of bisphosphonate treatment on the healing of rat tibial
fractures, the mechanical properties and radiological density of
the uninjured contralateral tibia was assessed. Skeletally mature aged rats were used. A total of 14 rats received
1µg/kg ibandronate (iban) daily and 17 rats received 1 ml 0.9% sodium
chloride (control) daily. Stress at failure and toughness of the
tibial diaphysis were calculated following four-point bending tests.Objectives
Methods
We evaluated the biomechanical properties of two different methods of fixation for unstable fractures of the proximal humerus. Biomechanical testing of the two groups, locking plate alone (LP), and locking plate with a fibular strut graft (LPSG), was performed using seven pairs of human cadaveric humeri. Cyclical loads between 10 N and 80 N at 5 Hz were applied for 1 000 000 cycles. Immediately after cycling, an increasing axial load was applied at a rate of displacement of 5 mm/min. The displacement of the construct, maximum
The use of two implants to manage concomitant ipsilateral femoral
shaft and proximal femoral fractures has been indicated, but no
studies address the relationship of dynamic hip screw (DHS) side
plate screws and the intramedullary nail where failure might occur
after union. This study compares different implant configurations
in order to investigate bridging the gap between the distal DHS
and tip of the intramedullary nail. A total of 29 left synthetic femora were tested in three groups:
1) gapped short nail (GSN); 2) unicortical short nail (USN), differing
from GSN by the use of two unicortical bridging screws; and 3) bicortical
long nail (BLN), with two angled bicortical and one unicortical bridging
screws. With these findings, five matched-pairs of cadaveric femora
were tested in two groups: 1) unicortical long nail (ULN), with
a longer nail than USN and three bridging unicortical screws; and
2) BLN. Specimens were axially loaded to 22.7 kg (50 lb), and internally
rotated 90°/sec until failure.Objectives
Methods
The June 2013 Shoulder &
Elbow Roundup360 looks at: whether suture anchors are still the gold standard; infection and revision elbow arthroplasty; the variable success of elbow replacements; sliding knots; neurologic cuff pain and the suprascapular nerve; lies, damn lies and statistics; osteoarthritis; and one- or two-stage treatment for the infected shoulder revision.