Journal of Orthopaedics and Traumatology
1590-9921
Cơ quản chủ quản: SPRINGER , Springer-Verlag Italia Srl
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Total hip replacement is showing, during the last decades, a progressive evolution toward principles of reduced bone and soft tissue aggression. These principles have become the basis of a new philosophy, tissue sparing surgery. Regarding hip implants, new conservative components have been proposed and developed as an alternative to conventional stems. Technical and biomechanical characteristics of metaphyseal bone-stock-preserving stems are analyzed on the basis of the available literature and our personal experience. Mayo, Nanos and Metha stems represent, under certain aspects, a design evolution starting from shared concepts: reduced femoral violation, non-anatomic geometry, proximal calcar loading and lateral alignment. However, consistent differences are level of neck preservation, cross-sectional geometry and surface finishing. The Mayo component is the most time-tested component and, in our hands, it showed an excellent survivorship at the mid-term follow-up, with an extremely reduced incidence of aseptic loosening (partially reduced by the association with last generation acetabular couplings). For 160 implants followed for a mean of 4.7 years, survivorship was 97.5% with 4 failed implants: one fracture with unstable stem, 1 septic loosening and 2 aseptic mobilizations. DEXA analysis, performed on 15 cases, showed a good calcar loading and stimulation, but there was significant lateral load transfer to R3–R4 zones, giving to the distal part of the stem a function not simply limited to alignment. Metaphyseal conservative stems demonstrated a wide applicability with an essential surgical technique. Moreover, they offer the options of a “conservative revision” with a conventional primary component in case of failure and a “conservative revision” for failed resurfacing implants.
Bisphosphonates have become the treatment of choice for a variety of bone diseases in which excessive osteoclastic activity is an important pathologic feature. However, inhibition of osteoclastic activity could lead to inhibition of remodeling during bone healing or repair. The objective of this study is to investigate the effect of zoledronate (the most potent bisphosphonate) in the biological process of bone healing.
Thirty immature male rabbits were divided into two groups (control and experimental) of 15 animals each. Both groups were submitted to fibular osteotomy. Only in the experimental group a single dose of zoledronate was administered. After 1, 2, and 4 weeks, animals of both groups were euthanized and the osteotomy site was histomorphometrically evaluated. The associated parameters analyzed were tissue volume (TV), fractional trabecular bone volume (BV/TV), fractional woven bone volume (WoV/TV), fractional periosteal fibrous volume (FbV/TV), and medullary fibrous volume (MaV/TV).
The first week of healing was characterized by small callus area (experimental group) and less periosteal fibrosis. The second week was characterized by a large quantity of woven bone and marked decrease in periosteal fibrosis in the two groups. In the control group there was also a significant increase in trabecular bone. The fourth week was characterized by increased amount of woven bone and trabecular bone in the experimental group; there was increased medullary fibrosis in the two groups, while there continued to be significantly less periosteal fibrosis in the experimental group.
Zoledronate does not prevent bone healing. However, the effect of zoledronate was characterized by accentuated stimulation of primary bone production and probably inhibition of remodeling, leading to retention of trabecular bone.
Roentgenographic and functional outcomes of expandable self locking intramedullary nailing and platelet rich plasma (PRP) gel in the treatment of long bone non-unions are reported.
Twenty-two patients suffering from atrophic diaphyseal long bone non-unions were enrolled in the study. Patients were treated with removal of pre-existing hardware, decortication of non-union fragments, and fixation of pseudoarthrosis with expandable intramedullary nailing (Fixion™, Disc’O Tech, Tel Aviv, Israel). At surgery, PRP was placed in the pseudoarthrosis rim.
The thirteen-month follow-up showed 91% (20/22 patients) of patients attaining bony union. The average time to union was 21.5 weeks. No infection, neurovascular complication, rotational malalignment, or limb shortening >4 mm were observed. The healing rate of non-unions was comparable to that observed in previous studies but with a lower complication frequency.
The combined use of self locking intramedullary nailing and PRP in the management of atrophic diaphyseal long bone non-unions seems to produce comparable results with less complications than previously reported. Further data are warranted to investigate the single contribution of PRP gel and Fixion nail.