Kinematic versus mechanical alignment in total knee arthroplasty: a preliminary study.

Despite the great advances of the technology in the joint prosthesis and the high execution rate of total knee arthroplasty (TKA), there are still about 15% of clinical unsatisfactory rate in this surgery. TKAs are currently performed using a mechanical alignment of the knee, correcting varus/valgus deformities with the purpose to achieve a longer implant survivorship, but this surgical technique results in an alteration of the normal knee kinematics. Nowadays, the idea to restore the pre-arthritic alignment of the knee with the goal to obtain a normal kinematics and better functional results becomes more and more consistent and the kinematic alignment (KA) was developed as alternative to the mechanical one. The aim of this preliminary study is to analyse the functional outcomes in patients who underwent KA-TKA in the short-term follow-up and to compare them with those obtained in patients treated by the mechanical alignment (MA) TKA. Therefore, skeletally mature patients, with no history of previous knee surgical procedures, who underwent isolated TKA for knee osteoarthritis, were included in this study. The patients were prospectively divided into two homogeneous groups according to the different surgical techniques performed (KA-TKA and MA-TKA groups). Clinical and functional scores (VAS, KOOS-PS, MCS-12, Final KSS, and Functional KSS) were collected pre- and postoperatively at a mean follow-up of 3 three months. As a result, 26 patients were included in the study, with a mean age of 69.3±7.61 years old (range: 55 - 84 years old). There were 38.5% male and 61.5% female. There were 13 patients in KA-TKA and 13 patients in MA-TKA. Three months after surgery each of the scores tested demonstrated statistically significant better outcomes in KA-TKA, compared to the MA-TKA group. MCS-12 resulted comparable in the two study groups. This preliminary study compares the short-term clinical and functional outcomes between KA and MA in total knee replacement. Further studies are required to confirm these results and to extend the sample size to obtain reliable clinical evidences.

Blood exposure has a negative effect on engineered cartilage.

PURPOSE: The aim of this study was to investigate the in vitro effect of different concentrations of blood on the morphological and biochemical properties of engineered cartilage. Previous studies have demonstrated a negative effect of blood on native cartilage; however, the effect of the contact of blood on engineered cartilage is unclear. METHODS: Articular chondrocytes were isolated from swine joints, expanded in monolayer culture, and seeded onto collagen membranes. The seeded membranes were cultured for 3 days in the presence of different concentrations of peripheral blood. Some samples were retrieved at the end of the blood contact, others after 21 additional days of standard culture conditions, in order to investigate the "long-term effect" of the blood contact. RESULTS: All seeded samples showed an increase in the weight and an evident cartilage-like matrix production. A concentration-dependent reduction in the mitochondrial activity due to blood contact was shown at the earlier culture time, followed by a partial recover at the longer culture time. CONCLUSION: A blood contact of 3 days affected the chondrocytes' activity and determined a delay in the maturation of the engineered cartilage. These findings have clinical relevance, as autologous chondrocytes seeded onto biological scaffolds has become an established surgical method for articular cartilage repair. Therefore, further investigation into material sciences should be encouraged for the development of scaffold protecting the reparative cells from the blood insult.

A tissue engineered osteochondral plug: an in vitro morphological evaluation.

Articular cartilage lesions have a poor intrinsic healing potential. The repair tissue is often fibrous, having insufficient biomechanical properties, which could frequently lead to the development of early osteoarthritis. In the last decade, tissue engineering approaches addressed this topic in order to restore joint function with a differentiated and functional tissue. Many biomaterials and techniques have been proposed and some of them applied in clinical practice, even though several concerns have been raised on the quality of the engineered tissue and on its integration in the host joint. In this study, we focused on engineering in vitro a biphasic composite made of cellular fibrin glue and a calcium-phosphate scaffold. Biphasic composites are the latest products of tissue engineering applied to articular cartilage and they seem to allow a more efficient integration of the engineered tissue with the host. However, a firm in vitro bonding between the two components of the composite is a necessary condition to validate this model. Our study demonstrated a gross and microscopic integration of the two components and a cartilage-like quality of the newly formed matrix. Moreover, we noticed an improvement of this integration and GAGs production during the in vitro culture.

Effect of blood on the morphological, biochemical and biomechanical properties of engineered cartilage.

The use of autologous chondrocytes seeded onto a biological scaffold represents a current valid tool for cartilage repair. However, the effect of the contact of blood to the engineered construct is unknown. The aim of this work was to investigate in vitro the effect of blood on the morphological, biochemical and biomechanical properties of engineered cartilage. Articular chondrocytes were enzymatically isolated from swine joints, expanded in monolayer culture and seeded onto collagen membranes for 2 weeks. Then, the seeded membranes were placed for 3 days in contact with peripheral blood, which was obtained from animals of the same species and diluted with a standard medium. As controls, some samples were left in the standard medium. After the 3 days' contact, some samples were retrieved for analysis; others were returned to standard culture conditions for 21 additional days, in order to investigate the "long-term effect" of the blood contact. Upon retrieval, all seeded samples showed increasing sizes and weights over time. However, the samples exposed to blood presented lower values with respect to the controls. Biochemical evaluation demonstrated a reduction in the mitochondrial activity due to blood contact at the early culture time (3 days post blood contact), followed by a partial recovery at the longer culture time (21 days post blood contact). Histological evaluation demonstrated evident cartilage-like matrix production for both groups. Biomechanical data showed a reduction of the values, followed by stabilization, regardless of the presence of blood. Based on the data obtained in this study, we can conclude that blood contact affects the chondrocyte activity and determines a delay in the dimensional growth of the engineered cartilage; however, at the experimental times utilized in this study, this delay did not affect the histological pattern and the biomechanical properties of the construct.

A comparative study on biochemical markers of bone collagen breakdown in post-menopausal women.

The aim of this study was to compare urinary galactosylhydroxylysine (GHyl) and deoxypyridinoline (d-Pyr) as biochemical markers of bone resorption in post-menopausal women treated and untreated with estrogen and cyclic etidronate. Fasting urinary GHyl, D-Pyr, pyridinoline, serum osteocalcin and total alkaline phosphatase were measured in three subgroups, i.e. post-menopausal women undergoing hormone replacement therapy, untreated post-menopausal women and post-menopausal women with low BMD treated with disodium etidronate. The results indicated that GHyl did not significantly discriminate between untreated post-menopausal women and estrogen replated ones unless an osteoporotic untreated group was selected. d-Pyr and GHyl showed similar performances when their values after bisphosphonate treatment were compared to those found in untreated post-menopausal women, thus suggesting that both markers were equal in their ability to detect the bone response to cyclic etidronate administration. This observation further proves the statement that GHyl is prone to confounding factors under estrogen therapy but it is adequate as is d-Pyr in monitoring the bone response to bisphosphonate treatment.

Effect of short course of 1,25-dihydroxyvitamin D3 on biochemical markers of bone remodelling in postmenopausal women.

This study was designed to test the hypothesis that a short treatment course of 1,25(OH)2D3 elicits a stimulation of osteoblast activity without any action on the osteoclast. To test this, oral daily doses of 0.5 microgram or 1 microgram of 1,25(OH)2D3 were administered for 7 days to two groups (n = 5 and n = 7, respectively) of postmenopausal women with low bone mineral density. Markers of osteoblast activity, i.e. osteocalcin (BGP), total alkaline phosphatase activity (ALP) and bone alkaline phosphatase activity (BALP), and markers of osteoclast activity, i.e. hydroxylysyl-pyridinoline (Pyr), lysyl-pyridinoline (D-Pyr), and galactosyl-hydroxylysine (GHyl) were measured in plasma and in fasting urinary samples, respectively, at sequential times during and after 1,25(OH)2D3 administration. It resulted that short term 1 microgram 1,25(OH)2D3 oral administration induced a significant (P < 0.05) rise of BGP serum level without any associated increase of D-Pyr and GHyl, the latter also expressed as GHyl to GGHyl ratio. Urinary Pyr increased significantly after 1 microgram daily doses of 1,25(OH)2D3. Thus, a short course of 1 microgram daily doses of 1,25(OH)2D3 elicits a stimulation of osteoblast activity without any enhancement of D-Pyr, the most specific marker of osteoclast activity. The enhancement of Pyr after 1 microgram daily doses of 1,25(OH)2D3 might be due to the activation of extraosseous metabolic pathways rather than to the activation of osteoclast.