Investigation of the effect of porous titanium cups on stress distribution in bone tissue (mathematical modeling)

Introduction. During arthroplasty in patients with altered anatomy and osteoporosis of the acetabulum, stable fixation of the acetabular component of the endoprosthesis is a very difficult task. There are studies on the bone tissue bonding to titanium, tantalum and ceramic coatings of endoprostheses. However, there are insufficient data on the influence of the strength characteristics of modern surfaces of the cups for hip endoprostheses on the distribution of mechanical stresses in the bone tissue around the implanted components. The purpose was to study on a mathematical model the changes in the stress-strain state of the endoprosthesis-bone system as a result of using porous tantalum cup. Materials and methods. A mathematical modeling has been carried out of the stress-strain state of the human hip joint in arthroplasty with porous cup. Du-ring the study, a defect in the acetabular roof filled with a bone implant fixed with two screws was simulated, as well as a defect in the acetabular floor filled with bone “chips”. Endoprosthesis cups were modeled in two versions: from solid titanium with a spray coating of porous titanium, and those entirely made of porous titanium. A distributed load of 540 N was applied to the sacrum. A load was applied between the iliac wing and the greater trochanter of the femur simulating the action of the gluteus medius — 1150 N and the gluteus minimus — 50 N. Results. The use of a cup with a coating of porous titanium in the normal state of the acetabulum leads to the occurrence of maximum stresses (15.9 MPa) in its posterior-upper part. Minimum stresses of 4.6 MPa are observed in the center of the acetabulum. The use of an endoprosthesis with porous titanium cup allows reducing the level of stresses in the bone tissue around the cup. If there is a defect in the acetabular roof, a hip endoprosthesis with porous titanium cup causes less stress than a solid titanium cup with coating of porous titanium. But on the graft, the stress level remains practically unchanged, regardless of the type of cup. The use of porous tantalum cup in the presence of a defect in the acetabular floor causes significantly less stress in the bone tissue around it, compared to an all-metal cup with coating. Conclusions. The cup of the hip endoprosthesis made of porous titanium causes significantly less stress in all control points of the model, compared to a cup made of solid titanium with coating of porous titanium, both with defects in the acetabular roof and floor, and without bone defects.

Use of Stand-Alone Intersomatic Titanium Interbody Cage Cespace for Cervical Anterior Arthrodesis and Fusion in Cervical Degenerative Diseases

Background: Cespace is a solid titanium spacer used for arthrodesis and fusion between vertebral cervical bodies in the treatment of degenerative diseases of cervical spine. Methods: We present our clinical experience in a group of 180 patients, affected by cervical myelo-radiculopathy due to spondylosis or cervical disc herniation and undergone surgical operation. All patients underwent an anterior discectomy and interbody fusion through positioning of one or more levels Cespace device. Patients were evaluated by clinical and radiological assessment pre-operatively, immediately post-operatively and at follow-up. We assess clinical outcome using visual analogue scale for pain and a modified Japanese Ortho­pedic Association scale for myelopathy. We also considered functional outcome, using Odom classification. Results: After surgical treatment we report a significant relief of pain and clinical improvement. Radiological evaluations showed no change in cervical lordosis. No case of junctional syndrome was observed over all follow-up period. Conclusion: Cespace is a safety and efficacious orientated solution for cervical interbody fusion.

Interaction between Ti-bearing ultra-low carbon solid steel and mold flux at 1400 °C

Laboratory scale experiments on the reaction between mold flux and solid titanium (Ti) bearing ultra low carbon (ULC) steel were carried out at 1400 °C. It was found that the composition of mold flux particles changed after the interactions, which was resulted from the reduction of flux components by the aluminum (Al) and Ti in steel, leading to the decrease of SiO2 and the increase of Al2O3 and TiOx in flux particles. A layer of oxides was precipitated in the steel near the steel-flux interface. Al2O3 particles were firstly precipitated and then transformed into Ti-Al-O type with the decrease of the distance from the interface and the increase of reheating time, accompanying with the increase of the particle size. The precipitation of particles was estimated to result from the reoxidation of the steel matrix by the oxygen diffused from the mold flux, which would further increase the detriment of the entrapped mold flux to the cleanliness and surface quality of the rolled sheets of ULC steel.

A mineral layer as an effective binder to achieve strong bonding between a hydrogel and a solid titanium substrate

This study has developed an effective strategy to bind a hydrogel with solid titanium by forming a CaCO3 layer at their interface.

Comparison study of compound fractures of tibial shaft treated by titanium and stainless steel interlocking nails

<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">The purpose of the present study was to compare the outcomes of compound fractures of tibia shaft managed by Solid Titanium and Stainless Steel interlocking intramedullary nailing.</span></p><p class="abstract"><strong>Methods:</strong> <span lang="EN-IN">This is a retrospective study of 45 patients with 45 open fractures of tibia shaft operated primarily by either Solid Titanium or Stainless steel tibia interlocking nail</span>.<strong></strong></p><p class="abstract"><strong>Results:</strong> <span lang="EN-IN">In Our Study we had 45 patients with 45 open tibial fractures. All were male. 35 patients were from 20-50 years age group. Mean age was 36.4 years. In this study of 45 open tibial fractures following strict protocol of thorough debridement, primary wound closure and Solid Titanium or stainless steel interlocking nailing; it was observed at final follow up that patients operated by titanium nail compared to stainless steel had 6.45% vs. 14.29% infection rate, 12.9% vs. 21.89% rate of non-union and 3.22% vs. 7.14% screw breakage rate. According to modified ketenjian’s criteria in our study out of 31 patients operated by Titanium interlocking nail 17 (54.84%) excellent, 10 (32.26%) Good, 3(9.68%) fair and 1(3.22%) poor functional results while out of 14 patients managed by stainless steel nail 8 (57.14%) excellent, 3 (21.43%) good, 1 (7.14%) fair and 2 (14.28%) poor functional results. </span></p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-IN">In open tibial fractures titanium interlocking implants offer lower complication rate as compared to stainless steel implants and better overall patient outcome.</span></p>