0000000000039929
AUTHOR
Klaus J. Burkhart
New intramedullary locking nail for olecranon fracture fixation--an in vitro biomechanical comparison with tension band wiring.
The aim of this study was to determine the difference in displacement of a newly designed intramedullary olecranon fracture fixation device compared with multifilament tension band wiring after 4 cycles and 300 cycles of dynamic continuous loading.In eight pairs of fresh-frozen cadaver ulnae, oblique olecranon fractures were created and stabilized using either newly designed intramedullary olecranon nail or multifilament tension band wiring. The specimens were then subjected to continuous dynamic loading (from 25 N to 200 N) using matched pairs of cadaveric upper extremities. The Wilcoxon test was used to determine statistical differences of the displacement in the fracture gap.After 4 cycl…
Dynamische Analyse von Osteosynthesen am Olecranon: ein in-vitro Vergleich zweier Osteosynthesesysteme / Dynamic analysis of olecranon osteosyntheses – an in vitro comparison of two osteosynthesis systems
INTRODUCTION The aim of the present study was to develop a test setup with continuous angle alteration to imitate elbow joint motion for the mechanical evaluation of tension band wiring and a newly designed intramedullary nail. MATERIALS AND METHODS The servo-pneumatical test stand worked with a rotational angle-adjusted and a linear force-adjusted engine. The fracture model was dynamically tested under cyclic loading imitating elbow joint motion. In total, 14 fresh cadaver upper extremities underwent olecranon fracture by means of transverse osteotomy and were assigned to two groups: tension band wiring and intramedullary nailing. There was a continuous angle alteration between 0 and 1000 …
Intramedullary nailing vs. palmar locked plating for unstable dorsally comminuted distal radius fractures: A biomechanical study
Abstract Background The purpose of this study was to compare the stability of a 2.4 mm palmar locking compression plate and a new intramedullary nail-plate-hybrid Targon DR for dorsally comminuted distal radius fractures. Methods An extraarticular 10 mm dorsally open wedge osteotomy was created in 8 pairs of fresh frozen human radii to simulate an AO–A3-fracture. The fractures were stabilized using one of the fixation methods. The specimens were loaded axially with 200 N and dorsal-excentrically with 80 N. 2000 cycles of dynamic loading and axial loading-to-failure were performed. Findings Axial loading revealed that intramedullary osteosynthesis (Targon DR: 369 N/mm) was significantly ( p …
Mid- to long-term results after bipolar radial head arthroplasty.
Background Radial head arthroplasty is considered the treatment of choice for unreconstructable radial head fractures in the acute fracture situation. Although short-term results in the current literature are promising, replacement of the radial head remains controversial as long-term results are still missing. We report our 8.8-year results after treatment with a bipolar radial head prosthesis by Judet. Materials and methods In our department, 19 patients were treated with bipolar radial head arthroplasty between 1997 and 2001. Seventeen of these patients—14 men and 3 women—were examined retrospectively after 106 months (range, 78-139). Of these, 9 patients were treated primarily, 7 patien…
Radial Head Fractures
Radial head fractures are the most common elbow fractures, accounting for 20–30 %. Typically, the fractures evolve from a fall on the outstretched hand with the elbow extended and the forearm in pronation. The role of the radial head as an important stabilizer of the elbow joint has been recognized in the last decade. Sixty percent of the axial load transmitted through the elbow is conducted through the radial head. Furthermore, the radial head is an important stabilizer against valgus stresses. While the medial collateral ligament (MCL) is the primary stabilizer against valgus stress, the role of the radial head emerges when the MCL is torn. These findings have led to a change in treatment…
Influence of formalin fixation on the biomechanical properties of human diaphyseal bone.
Owing to the lack of fresh human bones, formalin-fixed specimens are frequently used in biomechanical testing. However, formalin fixation is assumed to affect the biomechanical properties of bone. The aim of this study was to compare axial and torsional stiffness and bone mineral density in fresh and embalmed human bones. The subtrochanteric regions of 12 pairs of fresh human femora were randomised into two groups for paired comparison. After bone mineral density measurement, one group was preserved in 4% formalin. After 6 weeks, bone mineral density was remeasured and each specimen underwent axial and torsional loading. The formalin group showed significant higher stiffness values for tors…
Isolated fractures of the greater tuberosity of the proximal humerus
Background and purpose The diagnosis and treatment of isolated greater tuberosity fractures of the proximal humerus is not clear-cut. We retrospectively assessed the clinical and radiographic outcome of isolated greater tuberosity fractures. Patients and methods 30 patients (mean age 58 (26–85) years, 19 women) with 30 closed isolated greater tuberosity fractures were reassessed after an average follow-up time of 3 years with DASH score and Constant score. Radiographic outcome was assessed on standard plain radiographs. Results 14 of 17 patients with undisplaced or slightly displaced fractures (≤ 5 mm) were treated nonoperatively and had good clinical outcome (mean DASH score of 13, mean Co…
Distal Humerus Fractures
Distal humerus fractures display seldom but severe injuries because of the complex distal humerus anatomy and often comminuted fracture types. They account for approximately 2–3 % of all fractures and for 17–30 % of fractures around the elbow. In younger patients, there is a predominance among males. The mechanism of accident is mostly a high-energy trauma in this population. In contrast, among elderly patients, distal humerus fractures concern mostly women with osteoporotic bone. Fractures are caused by a low-energy trauma such as a fall from standing height onto the outstretched or slightly flexed arm. These fractures are often severely comminuted. Because of the thin soft tissue envelope…
Screw fixation of radial head fractures: Compression screw versus lag screw—A biomechanical comparison
Abstract Introduction Secondary loss of reduction and pseudarthrosis due to unstable fixation methods remain challenging problems of surgical stabilisation of radial head fractures. The purpose of our study was to determine whether the 3.0 mm Headless Compression Screw (HCS) provides superior stability to the standard 2.0 mm cortical screw (COS). Materials and methods Eight pairs of fresh frozen human cadaveric proximal radii were used for this paired comparison. A standardised Mason II-Fracture was created with a fragment size of 1/3 of the radial head's articular surface that was then stabilised either with two 3.0 mm HCS (Synthes) or two 2.0 mm COS (Synthes) according to a randomisation …
Dynamic biomechanical analysis of different olecranon fracture fixation devices--tension band wiring versus two intramedullary nail systems: an in-vitro cadaveric study.
Abstract Background. The aim of this study was to develop a test-setup with continuous angle alteration to imitate joint motion for the evaluation of 3 different olecranon fracture fixation devices. Methods. Twenty-one fresh cadaver upper extremities underwent olecranon fracture by the means of transverse osteotomy and received 3 different fixation systems. Group 1: Tension band wiring according to Weber. Group 2: XS-nail with 9 holes, all locked with 2 mm threaded K-wires. Group 3: Olecranon Nailing System with 90 mm length, locked with 2.7 mm screws, a variable angle locking hole for the proximal fragment and a proximal locking end cap. The servo-pneumatical test stand worked with a rotat…
Stability of radial head and neck fractures: a biomechanical study of six fixation constructs with consideration of three locking plates.
Open reduction and internal fixation of radial neck fractures can lead to secondary loss of reduction and nonunion due to insufficient stability. Nevertheless, there are only a few biomechanical studies about the stability achieved by different osteosynthesis constructs.Forty-eight formalin-fixed, human proximal radii were divided into 6 groups according to their bone density (measured by dual-energy x-ray absorptiometry). A 2.7-mm gap osteotomy was performed to simulate an unstable radial neck fracture, which was fixed with 3 nonlocking implants: a 2.4-mm T plate, a 2.4-mm blade plate, and 2.0-mm crossed screws, and 3 locking plates: a 2.0-mm LCP T plate, a 2.0-mm 6x2 grid plate, and a 2.0…
Number and Locations of Screw Fixation for Volar Fixed-Angle Plating of Distal Radius Fractures: Biomechanical Study
Purpose To compare the biomechanical properties of different numbers and locations of screws in a multidirectional volar fixed-angle plate in a distal radius osteotomy cadaver model. Methods We created an extra-articular fracture in 16 pairs of fresh-frozen human cadaver radiuses. The 32 specimens were randomized into 4 groups. All fractures were fixated with a multidirectional volar fixed-angle plate. We tested 4 different screw-placement options in the distal fragment. The distal fragment was fixed with 4 locking screws in the distal row of the plate in group a, and with 4 locking screws alternately in the distal and proximal rows in group b. In group c, 3 locking screws were used in the …
Finger injuries caused by power-operated windows of motor vehicles: an experimental cadaver study.
The aim of this experimental cadaver study was to investigate which kinds of lesions could occur in jam events between the glass and seal entry of power-operated motor vehicle side door windows at two different closing forces. Ten hands of fresh cadaver specimens were used. Three different hand positions chosen to simulate real events in which a finger is jammed between the glass and seal entry of the window of a current motor vehicle were examined. The index, middle, ring, and little finger of each hand were separately jammed both at the proximal and distal interphalangeal joint at closing forces of 300 and 500 N with a constant window glass closing speed of 10 cm/s. Macroscopically visibl…
The anatomy of the proximal radius: implications on fracture implant design.
Background The proximal radius features a complex anatomy. Several studies have been published on the anatomy using different technical approaches; however, most of these studies were conducted with a special focus on parameters relevant to radial prosthetic design. The purpose of our study was to explore the complex geometry of the proximal radius with regard to fracture implant design. Methods Our computed tomography-based measurements of 78 multiplanar reformatted radii allow for exact assessment of its geometry and offer a scientific rationale towards the design of fracture implants. We conducted measurements on the radial head, the radial neck, the radial tuberosity, the radial head-to…