Primary stability of osteochondral grafts used in mosaicplasty.

PURPOSE: The goal of our experiments was to determine the primary stability of osteochondral grafts used in mosaicplasty. The effect of graft diameter and dilation, as well as multiple grafting, were studied in a porcine model. METHODS: Single osteochondral grafts, 4.5 and 6.5 mm in diameter, and multiple grafts were transplanted from the trochlea of porcine femurs to the weight-bearing area of the lateral femoral condyle. In the multiple grafting series, 3 grafts 4.5 mm in diameter were transplanted either in a row or in circular fashion. The grafts were first pushed in level with the surrounding cartilage surface, then they were pushed 3 mm below cartilage level. The push-in forces were measured. The effect of graft diameter and the extent of dilation on primary stability were studied as well as the influence of multiple grafting. RESULTS: In the case of 4.5-mm grafts, the mean level push-in force was 43.5 N, and pushing 3 mm below cartilage level required a mean of 92.5 N (n = 13). In the case of 6.5-mm grafts, level push-in required a mean of 76.2 N, and for pushing 3 mm below cartilage level a mean of 122.2 N force had to be used (n = 14). The length of the drill hole and the dilation were both 20 mm in each setting. When using 20-mm long drill holes and 15-mm dilation length, the values above were found to be 36.6 N and 122.5 N in the case of 4.5-mm grafts (n = 12). Mean level push-in force in the first (row) multiple series was 31.8 N, and pushing 3 mm below cartilage level required a mean of 52.17 N (n = 7). In the second series (circle), level push-in required a mean of 30.44 N, and for pushing 3-mm below cartilage level a mean of 54.33 N force had to be used (n = 9). In the control series (1 single graft) the mean level push-in force was 38.7 N, and pushing 3 mm deeper required a mean of 86.8 N (n = 9). CONCLUSIONS: These results suggest that grafts of greater diameter are more stable in absolute values and stability may be increased by shorter dilation length, whereas level push-in forces do not increase significantly. There is no difference in primary stability between grafts implanted in a row or in circular fashion, and multiple grafts may not be as stable as single grafts in the initial period after transplantation. CLINICAL RELEVANCE: This is a randomized, controlled in vitro animal trial that helps us to better understand the primary stability of osteochondral grafts and to refine surgical techniques as well as postoperative protocols.

The effect of drill-hole length on the primary stability of osteochondral grafts in mosaicplasty.

Osteochondral grafts were transplanted from the trochlea of porcine femurs into drill holes that were 20, 15, and 12 mm in length on the lateral femoral condyle. Grafts initially were pushed in flush with the surrounding cartilage, and then a testing machine pushed the grafts 3 mm deeper. For the 20-, 15-, and 12-mm drill holes, mean forces for pushing the graft flush were 36.58, 43.33, and 118.13 N, respectively, while mean forces for pushing the graft 3 mm deeper were 122.50, 249.33, and 377.25 N, respectively. These results suggest primary stability is better when grafts and drill holes are the same length, but if the recipient hole is shorter, excessive force must be exerted on the cartilage cup during insertion.

Volume changes in intra- and extraorbital compartments in patients with Graves' ophthalmopathy: effect of smoking.

The objective of this study was to demonstrate the effect of smoking history on soft tissue expansion in specific orbital compartments in patients with Graves' ophthalmopathy. The volumes of the rectus muscles, intra and extraorbital connective, and soft tissues were measured in 110 orbits of 35 patients and 20 control subjects. Data sets from current smokers, ex-smokers, and non-smokers were compared. The total number of cigarettes smoked was calculated, and it was used as an estimate for the severity of smoking (cumulative smoking). The volume measurements were performed on T1-weighted contiguous transversal magnetic resonance images of the orbits. Connective tissue volumes were influenced by smoking history, while muscle volumes were not affected. Ex-smokers had larger amount of extraorbital connective tissue than current smokers (p = 0.012), and this volume showed a good correlation with the number of cigarettes smoked (r = 0.539, p < 0.05). In current smokers, the amount of intraorbital connective tissue correlated well with the cumulative smoking (r = 0.635, p < 0.001). We conclude that connective tissue volumes in certain orbital compartments correlate well with cumulative smoking. Extraocular muscle volumes are not influenced by smoking in patients with Graves' ophthalmopathy.

[Assessment of autoimmune disease activity in endocrine orbitopathy: comparison of SPECT using 99m-Tc-DTPA or 99m-Tc-depreotide and MRI scores]. / Az autoimmun folyamat aktivitásának megítélése izotópdiagnosztikai módszerekkel endokrin orbitopathiában: a 99mTc-DTPA, a 99m-Tc-depreotid SPECT és az MR összehasonlítása.

INTRODUCTION: Currently there is no ideal imaging technique which could estimate the degree of inflammation in thyroid eye disease. AIM: A new, rapid and cost-effective method, using 99mTc-labelled DTPA and 4-headed SPECT, was developed which is able to diagnose inflammatory activity in patients with endocrine orbitopathy (EOP). METHODS: The MRI T2 relaxation time was used as reference. Comparative orbital SPECT with the more specific 99mTc-Neospect (depreotide) was also performed in the same patients. RESULTS: Visual evaluation of orbital SPECT frames of patients suffering from active EOP could be easily distinguished from inactive EOP patients'. Despite the supposedly different characteristics of the two tested radiopharmaceuticals, there was essentially no difference between their accumulation in the orbit and the information obtained. The MRI activity scores correlated well with 99mTc-DTPA activity uptake (AU). The mean AU value in patients with inactive EOP was 6.26 +/- 1.6 10(-6) ID/cm3, while in active EOP 10.78 +/- 0.61 10(-6) ID/cm3, significantly higher. The 99mTc-DTPA accumulation in the orbital region in active disease was similar to that of depreotide. There was a good correlation (r = 0.91, P < 0.0001) between the two methods. CONCLUSION: The authors concluded that 99mTc-DTPA orbital SPECT is a potentially useful method, which--after initial clinical and MRI staging--gives useful quantitative estimation of disease activity in endocrine orbitopathy. It may provide important visual and quantitative information during the follow up of patients.

Altered signal pathway in angiotensin II-stimulated neutrophils of patients with hypercholesterolaemia.

Angiotensin II (AII) in 1-10 nM concentrations has an in vivo immunostimulating effect on human neutrophils. The release of superoxide anions and leukotrienes (LTs) is significantly increased by 10 nM AII-stimulated neutrophils of patients with hypercholesterolaemia (HCH). These oxidizing agents may be involved in the damage of vessel walls, i.e., in atherosclerotic plaque formation. To clarify the receptor types and signal pathways in neutrophils of healthy controls and patients, inositol trisphosphate (IP(3)) production and Ca(2+) signalling were studied. Neutrophils were pretreated before AII stimulation with different inhibitory drugs. In control cells, the stimulation occurred predominantly through pertussis toxin-sensitive, type angiotensin 1 receptors. This induced IP(3) production and Ca(2+) signalling from intracellular pools. In neutrophils of hypercholesterolaemic patients, the enhanced release of oxidizing agents was dependent more on type angiotensin 2 than type angiotensin 1 receptors. After stimulation, there was no IP(3) production detected. The Ca(2+) signalling was lower than in control cells and was dependent on extracellular Ca(2+).