Effects of merged holes, partial thread removal, and offset holes on fatigue strengths of titanium locking plates.

Background: This study investigated the effects of screw hole merging, thread removal, and screw hole offset on the mechanical properties of locking plates.

Methods: Finite element models were used to develop the optimal design of the merged holes. Four titanium locking plates with different hole designs were analyzed.

Contradictory working length effects in locked plating of the distal and middle femoral fractures-a biomechanical study.

Background: Working length have been reported to affect the plate stress and fixation stiffness. However, the results of previous studies have been controversial. The present study was to determine working length effects on different locations of femoral bone gap.

Half-threaded holes markedly increase the fatigue life of locking plates without compromising screw stability.

Aims: To determine whether half-threaded screw holes in a new titanium locking plate design can substantially decrease the notch effects of the threads and increase the plate fatigue life.

Methods: Three types (I to III) of titanium locking plates were fabricated to simulate plates used in the femur, tibia, and forearm. Two copies of each were fabricated using full- and half-threaded screw holes (called A and B, respectively).

Modification of the screw hole structures to improve the fatigue strength of locking plates.

Background: The fatigue fracture of locking plates can substantially threaten fracture treatment results. In the present study, three measures for modifying the screw hole structures of plates were implemented to improve their fatigue strength.

Materials: Custom-made identical titanium locking plates, except the screw hole configurations, were tested using four-point bending load.

Improving socket design to prevent difficult removal of locking screws.

Introduction: Reports of driver slippage leading to difficult locking screw removals have increased since the adoption of titanium for screw fabrication; the use of titanium is known to cause cross-threading and cold welding. Such problems occur most frequently in screws with hex sockets, and may cause serious surgical complications. This study aimed to improve screw socket design to prevent slippage and difficult screw removal.

The influence of renal dialysis and hip fracture sites on the 10-year mortality of elderly hip fracture patients: A nationwide population-based observational study.

Hip fractures in older people requiring dialysis are associated with high mortality. Our study primarily aimed to evaluate the specific burden of dialysis on the mortality rate following hip fracture. The secondary aim was to clarify the effect of the fracture site on mortality.

Notch sensitivity jeopardizes titanium locking plate fatigue strength.

Introduction: Notch sensitivity may compromise titanium-alloy plate fatigue strength. However, no studies providing head-to-head comparisons of stainless-steel or titanium-alloy locking plates exist.

Materials And Methods: Custom-designed identically structured locking plates were made from stainless steel (F138 and F1314) or titanium alloy.

Biomechanical evaluation of bending strength of spinal pedicle screws, including cylindrical, conical, dual core and double dual core designs using numerical simulations and mechanical tests.

Pedicle screws are used for treating several types of spinal injuries. Although several commercial versions are presently available, they are mostly either fully cylindrical or fully conical. In this study, the bending strengths of seven types of commercial pedicle screws and a newly designed double dual core screw were evaluated by finite element analyses and biomechanical tests.

High short-term and long-term excess mortality in geriatric patients after hip fracture: a prospective cohort study in Taiwan.

Background: Hip fracture has a high mortality rate, but the actual level of long-term excess mortality and its impact on population-wide mortality remains controversial. The present prospective study investigated short- and long-term excess mortality after hip fractures with adjustment of other risk factors. We calculated the population attributable risk proportion (PARP) to assess the impact of each risk factor on excess mortality.

Comparison study of the pullout strength of conventional spinal pedicle screws and a novel design in full and backed-out insertions using mechanical tests.

Recently, new pedicle screw designs have been developed. However, these designs' performances are still unclear, especially when backed out after insertion. The objective of this study was to investigate the performances of different screw designs when backed out from full insertion.

Multiobjective optimization design of spinal pedicle screws using neural networks and genetic algorithm: mathematical models and mechanical validation.

Short-segment instrumentation for spine fractures is threatened by relatively high failure rates. Failure of the spinal pedicle screws including breakage and loosening may jeopardize the fixation integrity and lead to treatment failure. Two important design objectives, bending strength and pullout strength, may conflict with each other and warrant a multiobjective optimization study.

Transosseous suturing of patellar fractures with braided polyester - a prospective cohort with a matched historical control study.

Background: Although tension-band wiring is the most widely used technique to fix patellar fractures, metal implant-related complications including implant failure and postoperative pain are very common and additional procedures are often necessary to treat the complications. The purpose of this study is to evaluate a totally metal-free technique using a transosseous suturing method and to compare it with the traditional fixation technique.

Method: A total of 25 patients (mean age of 59.

Hip fracture risk assessment: artificial neural network outperforms conditional logistic regression in an age- and sex-matched case control study.

Background: Osteoporotic hip fractures with a significant morbidity and excess mortality among the elderly have imposed huge health and economic burdens on societies worldwide. In this age- and sex-matched case control study, we examined the risk factors of hip fractures and assessed the fracture risk by conditional logistic regression (CLR) and ensemble artificial neural network (ANN). The performances of these two classifiers were compared.

Time orientation and visual construction subdomains of the MMSE as independent risk factors for hip fractures.

Hip fractures may result in severe morbidity and mortality among elderly patients. Many risk factors for hip fracture have been identified, including cognitive impairment. The authors used the Mini-Mental State Examination (MMSE), a screen test for cognitive impairment, as the study material for their hip fracture survey.

Risk factors for hip fracture sites and mortality in older adults.

Background: Our study was designed to (1) investigate the risk factors associated with cervical or trochanteric hip fractures; and (2) identify the risk factors for increased mortality in the elderly population sustaining hip fractures, after adjusting the miscellaneous baseline prefracture conditions.

Methods: Two hundred seventeen elder patients with first-time, low-trauma hip fractures were enrolled. The follow-up time ranged from 35 months to 56 months.

Comparison of multiple linear regression and artificial neural network in developing the objective functions of the orthopaedic screws.

Optimizing the orthopaedic screws can greatly improve their biomechanical performances. However, a methodical design optimization approach requires a long time to search the best design. Thus, the surrogate objective functions of the orthopaedic screws should be accurately developed.

A neurogenetic approach to a multiobjective design optimization of spinal pedicle screws.

A pedicle screw fixation has been widely used to treat spinal diseases. Clinical reports have shown that the weakest part of the spinal fixator is the pedicle screw. However, previous studies have only focused on either screw breakage or screw loosening.

Comparison of artificial neural network and logistic regression models for predicting mortality in elderly patients with hip fracture.

Purpose: Older patients with hip fracture have a mortality rate one year after surgery of 20-30%. The purpose of this study is to establish a predictive model to assess the outcome of surgical treatment in older patients with hip fracture.

Methods: A database of information from 286 consecutive cases of surgery for hip fracture from the Department of Orthopedics, National Taiwan University Hospital Yun-Lin Branch, was utilised for model building and testing.

Notch sensitivity of titanium causing contradictory effects on locked nails and screws.

The purpose of this biomechanical study was to compare the mechanical properties of specially designed locked nails and screws with the same structures and made from either stainless steel or titanium alloy. The structural factors investigated included inner diameter and root radius for locking screws and outer diameter and nail hole size for locked nails. The mechanical properties investigated included yield load, cyclic bending stiffness, and fatigue life.

Brachial plexus palsy caused by secondary fracture displacement in a patient with closed clavicle fracture.

In adults, brachial plexus injury due to clavicle fractures is rare, and is most commonly caused by nonunion, malunited fragments, hypertrophic callus, or pseudoaneurysm of the subclavicular artery or vein. Brachial plexus palsy in acute fractures caused by direct fragment compression is exceptional. Conservative treatment of nondisplaced and displaced midclavicle fractures in adults usually produces satisfactory outcomes.

Allografting in locked nailing and interfragmentary wiring for humeral nonunions.

Unlabelled: In this prospective study, we compared outcomes after repair of humeral nonunions when morsellized fresh-frozen allograft or autograft was used to augment repair by intramedullary nailing. Sixty-five patients with humeral shaft nonunions of greater than 6 months' duration and gross instability at the nonunion site were included and treated by locked nailing, interfragmentary wiring, and bone grafting. Graft type was determined by patient preference.

The in vivo performance of biomagnetic hydroxyapatite nanoparticles in cancer hyperthermia therapy.

Hyperthermia therapy for cancer has drawn more and more attention these days. In this study, we conducted an in vivo cancer hyperthermia study of the new magnetic hydroxyapatite nanoparticles by a mouse model. The magnetic hydroxyapatite nanoparticles were first made by co-precipitation method with the addition of Fe(2+).

Ultrasound stimulates NF-kappaB activation and iNOS expression via the Ras/Raf/MEK/ERK signaling pathway in cultured preosteoblasts.

It has been shown that ultrasound (US) stimulation accelerates fracture healing in the animal models and non-operatively clinical uses. Nitric oxide (NO) is a crucial early mediator in mechanically induced bone formation. Here we found that US-mediated inducible nitric oxide synthase (iNOS) expression was attenuated by Ras inhibitor (manumycin A), Raf-1 inhibitor (GW5074), MEK inhibitor (PD98059), NF-kappaB inhibitor (PDTC), and IkappaB protease inhibitor (TPCK).

Increasing nail-cortical contact to increase fixation stability and decrease implant strain in antegrade locked nailing of distal femoral fractures: a biomechanical study.

Background: Proximity of the distal locking screw to the fracture site potentially can cause implant failure in locked nailing of distal femoral fractures. In this biomechanical study, we investigated the effects of nail-cortical contact and nail purchase in the distal subchondral bone on fixation stability and implant strain.

Methods: Using fiberglass artificial femurs, we fixed five different distal femoral osteotomies with specially manufactured locked nails representing different conditions of nail-cortical contact.

Quadriceps-sparing, minimal-incision total knee arthroplasty: a comparative study.

Our study was conducted to compare radiographic alignments and functional outcomes with 2 approaches to minimal-incision total knee arthroplasty (TKA): the minimal-incision medial parapatellar (MP) approach and the quadriceps-sparing (QS) approach with side-cutting instruments. Sixty patients (80 knees) with primary osteoarthritis were randomly assigned to receive MP or QS TKA. Postoperative alignment of the femoral component was significantly less valgus, and postoperative alignment of the tibial component was significantly more varus with the QS approach than with the MP approach.