The effect of a new oral anticoagulant (Rivaroxaban) on implants pull-out strength. An experimental study in rats.

OBJECTIVES: Thromboprophylaxis reduces the risk of surgery related deep venous thrombosis and pulmonary embolism. The classical anticoagulants (heparin and LWMH) were associated with systemic osteoporosis, poor bone healing and materials' osseointegration. There is a lack of data concerning the effect of the new orally administered anticoagulants on osseointegration. The aim of this study is to investigate the possible effect of rivaroxaban, a direct anti-Xa factor, on osseointegration. METHODS: Twenty eight white, male, Wistar rats were divided into two groups: Group A, study group (n=14) and group B, control group (n=14). In all animals under general anesthesia one screw was inserted on the right tibia. For twenty eight days the animals of group A received intraperitoneal rivaroxaban injections 5mgr/kgr every day. The animals of group B received intraperitoneal equal amount of normal saline injections. At the end of the four weeks all animals were sacrificed and their right tibias were excised and underwent the pull-out test. RESULTS: The mean values of pull-out test were 92,10±19,12N for the control group and 95,46±21,02N for the study group. The statistical analysis using t-test showed no significant difference (p=0,665) for the pull-out test. CONCLUSIONS: These results indicate that Rivaroxaban hasn't got any deleterious effect on the osseointegration of implants on rats.

The serum levels of Receptor Activator of Nuclear Factor-κB Ligand, bone-specific alkaline phosphatase, osteocalcin and osteoprotegerin do not correlate with the radiographically assessed severity of idiopathic hip and knee osteoarthritis.

OBJECTIVES: Determination of the serum levels of Receptor Activator of Nuclear Factor-Κb Ligand, bone-specific alkaline phosphatase, osteocalcin and osteoprotegerin in patients suffering from osteoarthritis of varying severity and healthy controls and correlation of these results with the patients' age and the radiographically assessed severity of the disease. DESIGN AND METHODS: Patients suffering from hip (n=58) or knee (n=117) osteoarthritis and matched controls (n=19) were enrolled in this study. Patients underwent physical examination and standard radiographic evaluation before blood sampling. RESULTS: The serum levels of osteoprotegerin were positively correlated with age in all groups, whereas those of osteocalcin in the 'knee' group only. Osteoarthritis' severity and location did not have a statistically significant impact on the mean serum level of any marker in both groups. CONCLUSIONS: Based on our results, none of the studied markers can serve as a surrogate for radiographic imaging in patients suffering from hip and knee osteoarthritis.

Serum levels of bone turnover markers following total joint arthroplasty.

PURPOSE: To evaluate changes in serum levels of bone turnover markers during the first year following a total hip or knee arthroplasty (THA or TKA, respectively). METHODS: 34 women and 13 men (mean age, 68 years) with idiopathic hip or knee osteoarthritis underwent elective THA or TKA. The serum levels of (1) osteoprotegerin, (2) nuclear factor-kappa B ligand (RANKL), (3) osteocalcin, and (4) bone-specific alkaline phosphatase (b-ALP) were determined in each patient on preoperative day 1 and postoperative day 3 and 7, and month 2, 4, 6, 8, 10, and 12. RESULTS: All 4 markers changed significantly over the 12-month period. At month 12, values of all markers did not return to their preoperative levels uniformly. At month 8, the serum levels of osteoprotegerin, osteocalcin, and b-ALP remained higher than their respective preoperative values. The serum levels of RANKL gradually decreased after month 2, rendering this marker a potential index for fixation. CONCLUSIONS: Bone turnover markers change following arthroplasties. Postoperative month 8 seems to be a milestone in the normal course of these markers.

Primary cementless total hip arthroplasty with an alumina ceramic-on-ceramic bearing: results after a minimum of twenty years of follow-up.

BACKGROUND: The biological problems related to wear debris after total hip arthroplasty have stimulated renewed interest in alternatives to metal-on-polyethylene bearing surfaces. METHODS: We retrospectively evaluated the clinical and radiographic results of 100 patients who had undergone a total of 109 primary total hip arthroplasties with a cementless alumina ceramic-on-ceramic prosthesis between January 1985 and December 1989. The mean age of the patients at the time of the index arthroplasty was forty-six years. Clinical evaluation was performed with use of the Charnley modification of the Merle d'Aubigné-Postel scale. Seventy-eight patients who had had a total of eighty-five arthroplasties were available for follow-up evaluation at an average of 20.8 years. The patients' average age at the time of the latest follow-up was 66.8 years. RESULTS: Six hips (six acetabular cups and one femoral stem) in six patients underwent revision. Aseptic loosening of the cup combined with focal osteolysis was the cause of all six revisions. In one patient, the stem was also revised because of aseptic loosening. At the time of final follow-up, the result was excellent (according to the Merle d'Aubigné-Postel scale) in 68% of the hips, good in 19%, fair in 9%, and poor in 4%. The mean Merle d'Aubigné-Postel score improved from 7.9 points preoperatively to 16.9 points postoperatively (p < 0.001). The cumulative rate of survival of the prostheses was 84.4% at 20.8 years. CONCLUSIONS: The results of these cementless ceramic-on-ceramic total hip arthroplasties continued to be satisfactory at a minimum of twenty years postoperatively. The improved design of contemporary prostheses and the new generation of ceramic-on-ceramic bearing surfaces may lead to even better long-term results.

Reamed interlocking intramedullary nailing for the treatment of tibial diaphyseal fractures and aseptic nonunions. Can we expect an optimum result?

The need for reaming and the number of locking screws to be used in intramedullary (IM) tibial nailing of acute fractures as well as routine bone grafting of tibial aseptic nonunions have not been clearly defined. We describe the results of reamed interlocked IM nails in 233 patients with 247 tibial fractures (190 closed, 27 open and 30 nonunions). Ninety-six percent of the fractures were united at review after an average of 4.9 years. No correlation was found between union and nail diameter (P = 0.501) or the number of locking screws used (P = 0.287). Nail dynamization was effective in 82% of fractures. Locking screw(s) breakage was associated with nonunion in 25% of cases. Bone grafting during IM nailing was found not to increase the healing rate in tibial nonunions (P = 0.623). None of the IM nails were removed or revised due to infection. A dropped hallux and postoperative compartment syndrome were found in 0.8 and 1.6% of cases, respectively. Anterior knee pain was reported in 42% of patients but nail removal did not alleviate the symptoms in almost half. This series confirms the place of reamed intramedullary nailing for the vast majority of tibial diaphyseal fractures. It provides an optimum outcome and minimizes the need for supplementary bone grafting in aseptic nonunions.

Mid-term results of hydroxyapatite-coated threaded cup implanted without supplementary supporting screws.

We retrospectively reviewed the clinical, radiographic, and survivorship outcomes in a series of 180 patients that underwent 204 primary Total Hip Arthroplasties with the use of a second generation threaded hydroxyapatite-coated acetabular cup that was implanted without any supplementary supporting screws. At an average follow-up period of 10.2 (range: 8-14) years, one hundred and seventy-four patients (198 cups) were available for assessment. All patients underwent detailed physical and radiographic examination; their functional status was evaluated according to the Harris Hip Score (HHS). Following their digitization, all radiographs were further reviewed in order to determine the existence of any migration of the acetabular cup. Osteolytic lesions, radiolucent lines or zones of increased bone density were also recorded and classified according to the system of DeLee & Charnley. The modified Engh's criteria were used in order to evaluate the stability of the prosthesis. The patients' mean HHS at their latest follow-up visit (97.24 points) was statistically significantly better than the preoperative mean score of 40.31 points (p<0.001). Radiographic analysis showed "stable with bone ingrowth" fixation (modified Engh's criteria) of all implants with no significant migration of the cup (mean cranial migration: 0.597 mm, mean horizontal migration: 0.607 mm, mean observed difference of the cup's inclination angle: 0.26 degrees). No areas of significant osteolysis were found. The cumulative survival rate of the implants was 97.05%. Our results suggest that second generation hydroxyapatite-coated threaded acetabular cups can be successfully implanted (and achieve excellent results) without the use of any supplementary supporting screws.

Cementless total hip arthroplasty for osteonecrosis of the femoral head after allogenic bone marrow transplantation.

From 1998 until 2004, we performed 26 consecutive cementless total hip arthoplasties in 15 patients who had developed advanced avascular necrosis of the femoral head after allogenic bone marrow transplantation. The average age at transplantation was 31.1 years, and the mean age at implantation was 33.6 years. Follow-up period ranged from 2 to 8 years with an average of 56.4 months. The mean D'Aubigne-Postel score improved from 7.5 points preoperatively to 17 points postoperatively. The overall result was excellent in 92.3%, good in 3.8%, and fair in 3.8% of cases. There were no radiological signs of components loosening and no severe complications. Cementless total hip arthroplasty appears as a favorable alternative for the treatment of avascular necrosis of the femoral heads after allogenic bone marrow transplantation.