ABSTRACT
A number of interspinous devices (ISD) have been introduced in the lumbar spine implant market. Unfortunately, the use of these devices often is not associated with real comprehension of their biomechanical role. The aim of this paper is to review the biomechanical studies about interspinous devices available in the literature to allow the reader a better comprehension of the effects of these devices on the treated segment and on the adjacent segments of the spine. For this reason, our analysis will be limited to the interspinous devices that have biomechanical studies published in the literature.
Subject(s)
Biomechanical Phenomena/physiology , Intervertebral Disc/surgery , Lumbar Vertebrae/surgery , Prostheses and Implants , Prosthesis Implantation/instrumentation , HumansABSTRACT
UNLABELLED: In this report, we describe the effect of vitamin D and calcium supplementation on fracture healing in a young boy with a hypovitaminosis D who had a radius refracture. The radiographic evaluation of the callus formation shows a clear effect of vitamin D on fracture healing in absence of additional variables. INTRODUCTION: Fracture healing restores the tissue to its original physical and mechanical properties and it involves a complex multistep process that involves response to injury, intramembranous bone formation, chondrogenesis, endochondral bone formation, and bone remodeling. All this process is influenced by a variety of systemic and local factors. It is generally assumed that vitamin D plays an intimate role in healing fractures; however, very little data exists on how it does. CASE REPORT: In this report, the authors describe the effect of vitamin D and calcium supplementation on fracture healing in a young boy with a hypovitaminosis D who had a radius refracture. CONCLUSIONS: Our case report suggests that the hypovitaminosis D is a possible cause of inadequate fracture healing and refracture in children and it shows a clear effect of vitamin D supplementation on callus formation in the absence of additional variables.
Subject(s)
Fracture Healing/drug effects , Radius Fractures/prevention & control , Vitamin D Deficiency/diet therapy , Vitamin D/administration & dosage , Vitamins/administration & dosage , Calcium/administration & dosage , Child , Dietary Supplements , Humans , Male , Radiography , Radius Fractures/diagnostic imaging , Secondary Prevention , Vitamin D/analogs & derivatives , Vitamin D/blood , Vitamin D Deficiency/physiopathologyABSTRACT
The application of Dual-energy X-ray absorptiometry (DEXA) in orthopaedic surgery gradually has been extended from the study of osteoporosis to different areas of interest like the study of the relation between bone and prosthetic implants. Aim of this review is to analyze changes that occur in periprosthetic bone after the implantation of a total hip arthroplasty (THA) or a total knee arthroplasty (TKA). In THA the pattern of adaptive bone remodeling with different cementless femoral stems varies and it appears to be strictly related to the design and more specifically to where the femoral stem is fixed on bone. Short stems with metaphyseal fixation allow the maintenance of a more physiologic load transfer to the proximal femur decreasing the entity of bone loss. Femoral bone loss after TKA seems to be related to the stress shielding induced by the implants while tibial bone remodeling seems to be related to postoperative changes in knee alignment (varus/valgus) and consequently in tibial load transfer. After both THA and TKA stress shielding seems to be an inevitable phenomenon that occurs mainly in the first year after surgery.
