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Biomedical subjects

N Rozen

Publications and source records attributed to N Rozen.

8 recordsLinked to original sources
PubMed2006

Determinants of functional outcome after simple and complex acetabular fractures involving the posterior wall.

We have evaluated the functional, clinical and radiological outcome of patients with simple and complex acetabular fractures involving the posterior wall, and identified factors associated with an adverse outcome. We reviewed 128 patients treated operatively for a fracture involving the posterior wall of the acetabulum between 1982 and 1999. The Musculoskeletal Functional Assessment and Short-Form 36 scores, the presence of radiological arthritis and complications were assessed as a function of injury, treatment and clinical variables. The patients had profound functional deficits compared with the normal population. Anatomical reduction alone was not sufficient to restore function. The fracture pattern, marginal impaction and residual displacement of > 2 mm were associated with the development of arthritis, which related to poor function and the need for hip replacement. It may be appropriate to consider immediate total hip replacement for patients aged > 50 years with marginal impaction and comminution of the wall, since 7 of 13 (54%) of these required early hip replacement.

Acetabulum↗
PubMed2005

Complications encountered while using thin-wire-hybrid-external fixation modular frames for fracture fixation. A retrospective clinical analysis and possible support for "Damage Control Orthopaedic Surgery".

One hundred ninety eight adult patients who had sustained long bone fractures were treated by external fixation from admission to bone healing and consolidation. Of these, 135 had sustained high-energy injuries, 39 of them had suffered multi-system injuries. Superficial pin track infection was the most common complication, occurring predominantly in pins located in the femur, upper tibia and upper humerus. There were no cases of deep infection or osteomyelitis. One patient with a femoral shaft fracture developed a DVT although he was on preventive low molecular weight heparin, i.e. sc Clexane 40 mg daily. There were no cases of PE or ARDS. External fixation systems are a minimal invasive surgical modality, which allow three-dimensional fracture fixation after closed or minimal open reduction. They require a good command of surgical anatomy, but provide an optimal preservation of the fracture's soft tissue envelope, the critical biological factor for new bone formation and fracture healing. Recent publications have suggested that in the critically ill patient, minimally invasive fracture fixation surgery may prevent the perpetuation of a reactive, life threatening inflammatory reaction (the "second hit") which may induce the development of multiple organ dysfunction (MODS).

Adult↗
PubMed2001

Expression of vascular antigens by bone cells during bone regeneration in a membranous bone distraction system.

An in vivo system of membranous bone formation during distraction has been investigated in order to follow cells that express vascular markers with the objective of understanding the neovascularization process. Concomitantly, sustained proliferation of preskeletal cells was achieved through the application of mechanical force. New capillaries and leading edges that arose by angiogenesis from the periosteal and mucosal surfaces and invaded the central zone of the regenerating distraction tissue temporally preceded the growth of delicate woven bone trabeculae from both edges of the cut bone. Concentrically arranged 'onion-like' configurations were abundant in paracentral zones and in association with mesenchymal condensations, suggesting their de novo formation in situ. Vascular specific markers, the angiopoietin receptor Tie-2 and factor VIII-related antigen (FVIIIrAg), were localized immunohistochemically in order to follow cells of vascular origin. Endothelial cells of the new capillaries, centrally located cells of the concentric configurations, pericytes, and most of the adjacent polygonal mesenchymal cells stained positively with specific antibodies to both antigens. Moreover, preosteoblasts and osteoblasts that lie adjacent to or already embedded in the osteiod of the newly formed trabeculae were also FVIIIrAg and Tie-2 immunopositive. As the source of the bone-forming cells in regenerating tissue during distraction is not yet fully understood, this observation might support the possibility of their vascular origin.

Animals↗
PubMed2001

Tension-band arthrodesis of the small joints of the hand.

A review of 72 cases of tension-band arthrodesis in the small joints of the digits was conducted. Fusion was achieved in all joints with no complications apart from 2 cases of superficial infection. No failure of the hardware was noted, although hardware was removed in 5 patients after fusion was attained due to technical failure or pain. This technique provides immediate skeletal stability, thereby facilitating early digital motion and recovery.

Adult↗
PubMed2000

Interleukin-6 modulates trabecular and endochondral bone turnover in the nude mouse by stimulating osteoclast differentiation.

A great deal of evidence has been accumulating that implicates the immune system in normal and pathological bone turnover. The objective of the present study was to examine the possible involvement of cytokines produced by T lymphocytes in bone metabolism. We have chosen the immunologically compromised athymic mouse, which demonstrate sclerotic features in its trabecular bone, as the animal model for assessment of possible modulation effects of interleukin-1alpha (IL-1alpha) and interleukin-6 (IL-6) on bone and cartilage metabolism. The cytokines were applied by daily subcutaneous injections for 3 consecutive days. Histomorphometry, measuring epiphyseal trabecular bone volume (ETBV), metaphyseal trabecular bone volume (MTBV), and the width of the growth plate, and tartrate-resistant acid phosphatase (TRAP) histochemistry were used to assess parameters of bone turnover in the proximal tibia. IL-6, but not IL-1alpha, reduced ETBV and MTBV. Both IL-6 and IL-1alpha reduced the width of the growth plate. IL-6, but not IL-1alpha, increased the number of chondroclasts and osteoclasts in the primary spongiosa of the proximal tibia, as well as the number of nuclei. The resultant bone resembled that of the wild-type mouse. The results point to IL-6 as a possible regulator of bone turnover in vivo. It is suggested that the athymic mouse has a deficiency somewhere in the cascade of events leading to the production of IL-6 or, alternatively, that IL-6 replaces other factors that are supplied by T lymphocytes directly or indirectly. As T lymphocytes interact with B lymphocytes it is suggested that the athymic mouse might be appropriate for studying the in vivo effects of the immune system on normal bone metabolism.

Animals↗
PubMed1997

Ulnar nerve injury following midshaft forearm fractures in children.

We report three cases of ulnar nerve deficit in children following closed fractures of the forearm bones. Significant anterior angulation and displacement of the ulna was noted in all patients. Two patients were operated on at a later stage when no evidence of recovery was demonstrated; the ulnar nerve was found to be embedded in dense scar tissue. One patient was operated on at the time of injury; entrapment of the nerve on the anterior spike and partial transection was found. Early exploration is indicated in such cases and may result in full recovery.

Adolescent↗