Advertisement for orthosearch.org.uk
Results 1 - 7 of 7
Results per page:
Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_17 | Pages 12 - 12
1 Dec 2018
Oliveira P Leonhardt M de Carvalho VC Kojima K Rossi F Silva J Lima A
Full Access

Aim

Determine the incidence of surgical site infections (SSI) after intramedullary nailing (IN) of femoral and tibial diaphyseal fractures and evaluate possible risk factors.

Method

Prospective observational cohort study. SSI was defined according to CDC-NHSN criteria and surveillance period for the occurrence of infection was 12 months instead of the 90 days currently recommended. Incidence was calculated as the ratio between the number of patients with SSI and total number of patients. Analysis of potential risk factors included patients-related factors (age, gender, body mass index, active foci of infection, immunosuppressive conditions, ASA score, alcohol or illicit drug abuse, smoking, polytrauma, etiology of fracture, type of fracture if closed or open, classification of fracture according to Müller AO, Tcherne classification for closed fractures, Gustilo-Anderson classification and duration of bone exposure for open fractures, previous stay in other healthcare services, use of external fixator, previous surgical manipulation at same topography of fracture, use of blood products); environmental and surgical-related factors (surgical wound classification, duration of surgery, hair removal, intraoperative contamination, antimicrobial use, presence of drains, hypothermia or hypoxia in the perioperative period, type of IN used, reaming, need for muscle or skin flap repair, use of negative pressure therapy) and microbiota-related factors (presence of preoperative colonization by Staphylococcus aureus or Acinetobacter baumannii).


The Bone & Joint Journal
Vol. 98-B, Issue 7 | Pages 884 - 891
1 Jul 2016
Elliott DS Newman KJH Forward DP Hahn DM Ollivere B Kojima K Handley R Rossiter ND Wixted JJ Smith RM Moran CG

This article presents a unified clinical theory that links established facts about the physiology of bone and homeostasis, with those involved in the healing of fractures and the development of nonunion. The key to this theory is the concept that the tissue that forms in and around a fracture should be considered a specific functional entity. This ‘bone-healing unit’ produces a physiological response to its biological and mechanical environment, which leads to the normal healing of bone. This tissue responds to mechanical forces and functions according to Wolff’s law, Perren’s strain theory and Frost’s concept of the “mechanostat”. In response to the local mechanical environment, the bone-healing unit normally changes with time, producing different tissues that can tolerate various levels of strain. The normal result is the formation of bone that bridges the fracture – healing by callus. Nonunion occurs when the bone-healing unit fails either due to mechanical or biological problems or a combination of both. In clinical practice, the majority of nonunions are due to mechanical problems with instability, resulting in too much strain at the fracture site. In most nonunions, there is an intact bone-healing unit. We suggest that this maintains its biological potential to heal, but fails to function due to the mechanical conditions. The theory predicts the healing pattern of multifragmentary fractures and the observed morphological characteristics of different nonunions. It suggests that the majority of nonunions will heal if the correct mechanical environment is produced by surgery, without the need for biological adjuncts such as autologous bone graft.

Cite this article: Bone Joint J 2016;98-B:884–91.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_4 | Pages 85 - 85
1 Jan 2016
Ueshima M Yoshimura N Otsuki M Hatano N Tamura N Iwasaki Y Ishihara K Tamada Y Kojima K Kambe Y Akahane M Shimizu T Tanaka Y Tomita N
Full Access

Introduction

It is essential to investigate the tribological maturation of tissue-engineered cartilage that is to be used in medical applications. The frictional performances of tissue engineered cartilage have been measured using flat counter surfaces such as stainless steel, glass or ceramics. However, the measured friction performances were significantly inferior to those of natural cartilage, likely because of cartilage adhesion to the counter surface. Tamura et al. reported that a poly (2- methacryloyloxyethyl phosphoryl-choline (MPC)) grafted surface shows low friction coefficient against cartilage without the adhesion to be equivalent to those for natural cartilage-on-cartilage friction. [1]

On the other hand, Yamamoto et al. reported that applying a relative sliding movement had a potential to alter the expression of tribological function of regenerated cartilage of chondrocytes. [2] In this paper, the effects of the relative sliding movement on the expression of bone marrow stromal cells (BMSC)s were investigated using the poly(MPC) grafted surface as a counter surface.

Material and methods

BMSCs seeded onto fibroin sponge scaffolds were cultured by using the stirring chamber system (Figure 1), which can apply a relative tribological movement to the surface of the specimens. Three culture conditions were applied (dynamic in stirring chamber as frequency as 40 min [D1], as 40 sec [D2] and static in stirring chamber group [S]). The specimens were set into stirrer on a poly(MPC) grafted surface (MPC polymer coated surface, SANSYO).

As a counter surface in friction tests, the poly(MPC) grafted surface was prepared by atom transfer radical polymerization, and the regenerated cartilage was prepared by seeding 5×105 cells (BMSCs from rat bone marrow) onto fibroin sponge scaffolds (8 mm diameter and 1 mm thickness) and by 14 days culture.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_3 | Pages 141 - 141
1 Jan 2016
Ryu K Suzuki T Iriuchishima T Kojima K Saito S Ishii T Nagaoka M Tokuhashi Y
Full Access

Objective

Mobile bearing unicompartmental knee arthroplasty (UKA) is an effective and safe treatment for osteoarthritis of the medial compartment. However, mobile-bearing UKA needs accurate ligament balancing of flexion and extension gaps to prevent dislocation of the mobile meniscal bearing. Instability can lead to dislocation of the insert. The phase 3 instruments of the Oxford UKA use a balancing technique for the flexion gap (90° of flexion) and extension gap (20° of flexion), thereby focusing attention on satisfactory soft tissue balancing. With this technique, spacers are used to balance the flexion and extension gap. However, gap kinematics in another flexion angle of mobile-bearing UKA is unclear. We developed UKA tensor for mobile-bearing UKA and we assessed the accurate gap kinematics of UKA.

Materials and Methods

Between 2012 and 2013, The Phase 3 Oxford Partial Knee UKA (Biomet Inc., Warsaw, IN) were carried out in 48 patients (71 knees) for unicompartmental knee osteoarthritis or spontaneous osteonecrosis of the medial compartment. The mean age of patients at surgery was 71.6 years and the mean follow-up period was 1.7 years. The mean preoperative coronal plane alignment was 7.4° in varus. The indications for UKA included disabling knee pain with medial compartment disease; intact ACL and collateral ligaments; preoperative contracture of less than 15°; and preoperative deformity of <15°. Each surgery was performed by using different spacer block with 1-mm increments and the meniscal bearing lift-off tests according to surgical technique. We developed newly tensor for mobile bearing UKA which designed to permit surgeons to measure multiple range of the joint medial compartment/joint component gap, while applying a constant joint distraction force (Figure 1). We assessed the intra-operative joint gap measurements at 0, 20, 60, 90 and 120 of flexion with 100N, 125N and 150N of joint distraction forces.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 77 - 77
1 Jul 2014
Kojima K Lenz M Nicolino T Hofmann G Richards R Gueorguiev B
Full Access

Summary Statement

Tibia plateau split fracture fixation with two cancellous screws is particularly suitable for non-osteoporotic bone, whereas four cortical lag screws provide a comparable compression in both non-osteoporotic and osteoporotic bone. Angle-stable locking plates maintain the preliminary compression applied by a reduction clamp.

Introduction

Interfragmentary compression in tibia plateau split fracture fixation is necessary to maintain anatomical reduction and avoid post-traumatic widening of the plateau. However, its amount depends on the applied fixation technique. The aim of the current study was to quantify the interfragmentary compression generated by a reduction clamp with subsequent angle-stable locking plate fixation in an osteoporotic and non-osteoporotic synthetic human bone model in comparison to cancellous or cortical lag screw fixation.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 543 - 543
1 Dec 2013
Suzuki T Ryu K Yamada T Kojima K Saito S Tokuhashi Y
Full Access

Introduction

Accurate soft tissue balancing in knee arthroplasty is essential in order to attain good postoperative clinical results. In mobile-bearing UKA (Oxford Partial Knee unicompartmental knee arthroplasty, Biomet), since determination of the thickness of the spacer block depends on the individual surgeon, it will vary and it will be difficult to attain appropriate knee balancing. The first objective of the present study was to investigate flexion and extension medial unicompartmental knee gap kinematics in conjunction with various joint distraction forces. The second objective of the study was to investigate the accuracy of gap measurement using a spacer block and a tensor device.

Methods

A total of 40 knees in 31 subjects (5 men and 26 women) with a mean age of 71.5 years underwent Oxford UKA for knee osteoarthritis and idiopathic osteonecrosis of the medial compartment. According to instructions of Phase 3 Oxford UKA, spacer block technique was used to make the extension gap equal to the flexion gap. Adequate thickness of the spacer block was determined so that the surgeon could easily insert and remove it with no stress. Following osteotomy, the tensor devise was used to measure the medial compartmental gap between the femoral trial prosthesis and the tibial osteotomy surface (joint component gap) (Fig. 1 and 2). The medial gap was measured at 20° of knee flexion (extension gap) and 90° of knee flexion (flexion gap) with 25N, 50N, 75N, 100N, 125N, 150N of joint distraction force. Corresponding size of bearing was determined for the prosthesis. The interplay gap was calculated by subtracting the thickness of the tibial prosthesis and the thickness of the selected size of bearing from the measured extension and flexion gaps.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 184 - 184
1 Sep 2012
Takahashi K Kambe Y Hayashi N Yamada K Yamamoto K Kojima K Tamada Y Tomita N
Full Access

INTRODUCTION

Several reports suggest that low-intensity pulsed ultrasound stimulation (LIPUS) facilitates chondrogenesis1). Recently it has been suggested that LIPUS may be transmitted via Integrin: a protein which mediates cellular attachment between cells and extracellular matrix2). In this study, the Arg-Gly-Asp (RGD) amino acid sequence, which is a ligand of Integrin, was induced to the fibroin substrates by either gene transfer or physical mixing, and the variation of chndrocyte response to LIPUS was evaluated.

EXPERIMENTAL METHODS

Three kinds of culture dishes coated with three diffrent fibroin aqueous solutions were prepared: 1 wild-type, 2 transgenic and 3 mixed. The wild-type aqueous solution was prepared from Bombyx mori silkworm cocoons. The transgenic aqueous solution was prepared from Bombyx mori silkworm cocoons in which RGD was interfused in the fibroin light chain3). The mixed aqueous solution was prepared simply by blending RGD peptides with the wild-type fibroin aqueous solution. Chondrocytes were asepically harvested from the joints of 4-week-old Japanese white rabbits and then subcultured on T-flasks and seeded at 2.0 × 105 cells/dish. LIPUS stimulation, with spatial and temporal average intensity of 30 mW/cm2 and a frequency of 1.71 MHz with a 200 ms tone burst repeated at 1.0 kHz, was applied to the chondrocytes at 12, 36, 60 hours and administered for 20 minutes each time. GAG production and the number of chondrocytes were measured by the Dimethylmethylene blue (DMMB) method4) and the LDH method5), respectively. Extracted mRNA from the chondrocytes was analyzed by using the Syber Green method, where the primers were designed for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as the house-keeping gene, aggrecan and Sox 9. This data was analyzed using the two-sided Student's t-test.