Long-term biologic fate of neoarteries regenerated in microporous, compliant, biodegradable, small-caliber vascular grafts in rats

Microporous, compliant, biodegradable vascular grafts prepared from a mixture of polyurethane [( PU], 95% weight) and poly-L-lactide [( PLLA] 5% weight) can function as temporary scaffolds for the regeneration of the arterial wall of small-caliber arteries. The purpose of this study was to determine the long-term biologic fate of these neoarteries that were regenerated in PU/PLLA vascular grafts. The PU/PLLA vascular grafts (1.5 mm internal diameter [ID]) were implanted into the abdominal aortas of rats (N = 8) and were evaluated 1 year after implantation by means of macroscopic inspection, light microscopy, and electron microscopy. All implants were patent; three implants were normally shaped, two were slightly dilated (+/- 10% of the original ID), and three implants were aneurysmal. Arterial pulsations were reduced but still visible in the normally shaped implants and absent in the other implants. In all implants, the neointima was complete. The neomedia varied among the implants: In the normally shaped implants, smooth muscle cells were predominantly circularly arranged as in normal arterial tissue; in the other implants, smooth muscle cells were predominantly longitudinally arranged. The neoadventitia showed a completely fragmented graft lattice, which was organized by fibrohistiocytic tissue. These results suggest that the pattern of arrangement of smooth muscle cells in the neomedia determines the ultimate biologic fate of neoarteries regenerated in microporous, compliant, biodegradable vascular grafts. Only those neoarteries with predominantly circularly arranged smooth muscle cells in the neomedia were able to function normally as an arterial substitute for a 1-year period after implantation into the rat abdominal aorta.     

Microporous, complaint, biodegradable vascular grafts for the regeneration of the arterial wall in rat abdominal aorta

Microporous, complaint, biodegradable vascular grafts prepared from mixtures of polyurethane (PU) and poly-L-lactic acid (PLLA) can function as temporary scaffolds for the regeneration of the arterial wall in small-caliber arteries. This study was undertaken to determine the most suitable composition for PU/PLLA vascular grafts to ensure an optimal regeneration. Four types of PU/PLLA vascular grafts differing in percent weight of the PU/PLLA mixture, molecular weight of PLLA, and pore size were implanted into the abdominal aorta of rats (n = 32). Six weeks after implantation two implants of each graft type were evaluated by means of scanning electron microscopy and six implants were evaluated by means of light microscopy. In two types of the PU/PLLA vascular grafts, both of which were prepared from a 95%/5% weight PU/PLLA mixture with PLLA of molecular weight 500,000 but which had a different pore size, there was (I) absence of aneurysm formation and maintenance of arterial implant pulsations, (II) regeneration of a complete antithrombogenic neointima, (III) regeneration of a neomedia of comparable thickness to the media of normal rat abdominal aorta with the regeneration of elastic laminae almost throughout its thickness, and (IV) regeneration of a sufficiently supporting neoadventitia. These results demonstrate that a 95%/5% weight PU/PLLA mixture with PLLA of molecular weight 500,000 is the most suitable composition for PU/PLLA vascular grafts to ensure an optimal regeneration of a neoarterial wall that is of sufficient strength, compliance, and thromboresistance to function as a small-caliber arterial substitute. Pore size of these PU/PLLA grafts does not affect regeneration.     

Arterial wall regeneration in small-caliber vascular grafts in rats. Neoendothelial healing and prostacyclin production

Clinically available synthetic graft materials frequently fail when used as a small-caliber arterial substitute. Therefore, we developed a new type of graft material, prepared from a mixture of polyurethane and poly-L-lactic acid, to be used as a scaffold for the regeneration of the arterial wall. In this study microporous, compliant, biodegradable polyurethane/poly-L-lactic acid grafts (n = 16) and polytetrafluoroethylene grafts (n = 16) were implanted in the rat abdominal aorta and evaluated 3, 6, and 12 weeks after implantation. First, we evaluated the extent of neoendothelial healing (n = 8) by means of light microscopy and scanning electron microscopy. Next, we studied the ability of the neoendothelial cells to produce prostacyclin (n = 8) by means of bioassay for prostacyclin and radioimmunoassay for its stable hydrolysis product, 6-oxo-prostaglandin F1 alpha. There were no significant differences between the two graft types in the amount of prostacyclin production per unit graft area covered with neoendothelium, and this amount was the same as for normal endothelium. However, the polytetrafluoroethylene grafts showed incomplete neoendothelial healing, even after 12 weeks of implantation, in contrast to the polyurethane/poly-L-lactic acid grafts. The better healing characteristics of the polyurethane/poly-L-lactic acid grafts ensured the fast development of a complete neoarterial wall, possessing strength, compliance, and thromboresistance equivalent to normal arterial wall tissue. These results demonstrate that arterial wall tissue regeneration in polyurethane/poly-L-lactic acid grafts may open new perspectives in the field of arterial reconstructive surgery.     

Endothelialization of microporous polytetrafluoroethylene grafts in the infrarenal aorta and caval vein of the rat.

To study healing and endothelialization of vascular grafts, microporous polytetrafluoroethylene (PTFE) prostheses 2 mm in inner diameter and 5 mm long were implanted into the infrarenal aorta or caval vein of the rat. Patency was assessed in six rats from each group at days 3, 7, 14, 28, and 56 after implantation. Four grafts were occluded, two in the aorta (56 days) and two in the caval vein (3 and 14 days). The prostheses were examined via scanning electron and light microscopy for evaluation of endothelialization. At 3 days, the inner surface of the aortic grafts was covered by a plasma proteinaceous layer and that of the caval vein grafts by a thin mural thrombus. Endothelial cells then migrated from aorta/caval vein edges over the graft. At 14 days, the caval vein grafts were completely re-endothelialized, and, at 28 days, the mural thrombus in these grafts was replaced by neointima. In contrast, endothelialization of the aortic grafts had advanced only 1 mm at about 56 days, never forming a complete endothelial layer. We conclude that endothelialization of microporous PTFE prostheses is more rapid and complete in the caval vein than in the aorta of the rat.     

In vivo study of an elastomer end-coated polytetrafluoroethylene vascular prosthesis.

Polyurethane end-coated polytetrafluoroethylene (PTFE) grafts (elastomer PTFE grafts) were implanted in 12 female adult mongrel dogs to assess patency, intimalization, tissue incorporation, and technical suitability of the material as a vascular graft. Each dog had bilateral aortoiliac grafts placed, one a standard PTFE and the other an elastomer PTFE graft. The length of the grafts was 7-8 cm and the diameter was 6 mm. The grafts were harvested at intervals to 120 days postoperatively. The elastomer PTFE grafts showed superior longitudinal elasticity, retention of shape, and no graft tearing with suture tension; however, no significant difference in bleeding was noted at the anastomoses between the standard and elastomer PTFE grafts. Satisfactory patency was obtained with both standard (8/10) and elastomer PTFE grafts (9/10) at 90-120 days. No significant difference in the thickness of intima and the length of pannus ingrowth was noted between the standard and elastomer PTFE grafts. No outer tissue incorporation was seen at the elastomer-treated graft segments as opposed to the well-incorporated untreated segments. In conclusion, elastomer end-coating of a PTFE vascular prosthesis provided excellent handling characteristics without detracting from patency; however, the lack of outer tissue incorporation may be a potential disadvantage in its clinical use.     

Influence of prosthetic graft fabrication on graft healing,I

The object of this report was to analyze graft healing by comparing the content of collagen and noncollagen protein among seven commonly used prostheses: light-weight knitted dacron concentric crimp (USCI), Sauvage filimentous external velour knitted dacron with concentric crimp, random crimp, or no crimp (USCI), microvel double-velour knitted dacron concentric crimp (Meadox), PTFE Impra, and PTFE Gortex. Grafts (6 mm) were used to replace 4-cm segments of infrarenal abdominal aorta in 85 experimental dogs and five autograft aorta control animals. At 3 and 6 months postimplantation the grafts were aseptically harvested, inspected for completeness of neointimal healing and submitted for biochemical analysis. After 3 months implantation, uncrimped external velour grafts had less hydroxyproline than all dacron grafts except random crimp external velour (P < 0.05) but not less than both PTFE grafts and most dacron and PTFE grafts were not significantly different in noncollagen protein. After 6 months implantation, all dacron grafts had more hydroxyproline than both PTFE grafts (P < 0.03) and most dacron grafts had significantly more noncollagen protein than PTFE Impra (P < 0.05). Of all the grafts analyzed, only uncrimped external velour knitted dacron grafts had both rapid neoendothelial healing and a significant increase in both hydroxyproline and noncollagen protein between 3 and 6 months after graft implantation (P < 0.01). These data indicate that dacron prostheses heal in a manner different from that of PTFE grafts, that there may be differences among the various types of dacron prostheses, and that external velour uncrimped grafts would appear to have the best healing characteristics.     

Novel synthetic selectively degradable vascular prostheses: a preliminary implantation study

BACKGROUND: Vascular grafts perform less well than autologous arterial or vein grafts. The purpose of this study was to evaluate the short-term performance of selectively biodegradable filament-wound vascular prostheses, comprising elastomeric poly(ether urethane) (Lycra) scaffolds and flexible, hydrophilic biodegradable coatings. MATERIALS AND METHODS: Two types of selectively biodegradable vascular grafts were manufactured, comprising a filament-wound Lycra scaffold, subsequently coated with a biodegradable poly(ethylene glycol)/poly(lactic acid) (PELA) block copolymer. The two types of grafts differed in both the overall porosity of the scaffold and the hydrophilicity of the biodegradable constituent. A 60-mm-long and 6-mm-diameter filament-wound and polytetrafluoroethylene (ePTFE) grafts were implanted as interposition prostheses, randomly, at the right- and left-side carotid arteries. RESULTS: Implantation studies proved the grafts to be patent and pulsatile for periods of up to 3 months. Increasing the scaffold porosity and enhancing the hydrophilicity of the biodegradable component improved both the transmural tissue ingrowth process and the vascularization of the prosthesis wall. Also, a well-adhered peripheral tissue and a thin, uniform intima and endothelial lining were obtained. All ePTFE graft controls, although patent, were rather stiff and nonpulsatile. A thick pseudointima, poorly attached to the prosthesis inner surface, was observed. The compliance of the wet grafts was significantly higher than in the dry state, stemming mainly from the water-plasticizing effect on the biodegradable component. The grafts explanted after a period of 6 weeks exhibited compliance only slightly lower than that of the wet grafts. After 12 weeks, however, the hoop compliance was 20% lower than that prior to implantation. At 100 mm Hg, for example, the original compliance of the wet graft was 2.5%/100 mm Hg decreasing to 2.0%/100 mm Hg after a 3-month implantation. The compliance reduction with implantation is attributed to the ingrowth of the perigraft tissue as revealed by the histological study. A compliance of 2.0%/100 mm Hg is slightly better than that of a standard PTFE graft with an original compliance of 1.6%/100 mm Hg. Yet it is still an order of magnitude smaller than that of a canine carotid artery. CONCLUSIONS: The improved mechanical properties and enhanced healing of the highly porous filament-wound Lycra scaffold graft coated with hydrophilic biodegradable PELA has the potential of being a highly effective small caliber prosthetic graft.     

Infection of vascular prostheses caused by bacterial biofilms

A canine model was developed to study the efficacy of graft replacement as treatment for vascular prosthesis infections from Staphylococcus epidermidis. Infrarenal aortic graft infections were established in 18 dogs by implantation of Dacron prostheses colonized in vitro with a slime-producing strain of S. epidermidis to form an adherent bacteria-laden biofilm (5 X 10(6) colony-forming units/cm2 graft). Study animals developed a graft infection with anatomic and microbiologic characteristics typical of late prosthetic graft infections in humans (sterile perigraft exudate, absent graft incorporation, and normal serum leukocyte count and sedimentation rate). The S. epidermidis study strain was isolated from 14 of 18 explanted grafts (78%) by mechanical disruption of the graft surface biofilm and culture in broth media. Four dogs with sterile graft cultures had histologic evidence of bacterial infection. The established prosthetic surface biofilm infection was treated by graft excision, parenteral cefazolin, and graft replacement with a Dacron or polytetrafluoroethylene (PTFE) vascular prosthesis. One month after graft replacement, no PTFE graft had signs of infection, but perigraft exudate and inflammation involved three of nine Dacron grafts (33%). The study strain was recovered from four of nine PTFE grafts (44%) and two of nine Dacron (22%) replacement grafts (p greater than 0.05). Prosthetic replacement of Dacron prostheses infected by S. epidermidis as a bacteria-laden surface biofilm can result in early graft healing, but persistent colonization of one third of replacement grafts signify that recurrent clinical infection remains a risk.     

Mechanisms of healing in synthetic grafts

In previous baboon studies we have shown that porous (60 micron mean internodal distance) polytetrafluoroethylene (PTFE) grafts heal by ingrowth of endothelium and smooth muscle cells from the adjacent artery and from capillaries penetrating through the interstices of the graft. However, porous grafts (principally made of Dacron) in humans do not heal. This has been attributed to a wound healing deficiency in humans; however, it might be due to an inhibitory effect of the Dacron itself. To examine the latter possibility, we undertook this study to compare the healing of 4 mm internal diameter porous Dacron grafts (USCI, Sauvage Filamentous Knitted) with that of Gore-Tex 60 micron PTFE grafts in baboons (the latter graft not available for clinical use). The grafts were harvested at 2, 4, and 12 weeks and assessed for (1) percentage of endothelial coverage, (2) endothelial cell (EC) proliferation (thymidine labeling index), (3) intimal area, and (4) smooth muscle cell (SMC) proliferation (thymidine labeling index). The PTFE grafts at all three time points were fully covered, whereas only one of five Dacron grafts was completely covered at 12 weeks. The intima of the PTFE grafts consisted of ECs and SMCs, whereas that of the Dacron grafts contained ECs and SMCs as well as focal accumulations of thrombus. The intimal cross-sectional areas in the Dacron grafts (3.0 +/- 1.2 mm2) were significantly greater than in the PTFE grafts (0.8 +/- 0.6 mm2) at 4 weeks; there was no difference at 12 weeks (Dacron, 2.6 +/- 2.3 mm2 and PTFE, 3.0 +/- 2.5 mm2).(ABSTRACT TRUNCATED AT 250 WORDS)     

Presence of a uterine horn and fallopian tube within an indirect hernial sac: report of a rare case

An inguinal hernia containing an ovary, fallopian tube, and uterus is an extremely rare occurrence in a woman of reproductive age. We herein report a case of a uterine horn from a bicornuate uterus, left ovarian ligament, and partially left fallopian tube within the left inguinal sac and canal diagnosed through laparoscopy in a 23-year-old female who is infertile.     

Polytetrafluoroethylene (PTFE) grafts for haemodialysis: patency and complications compared with those of saphenous vein grafts.

A comparison has been made between polytetrafluoroethylene (PTFE) and saphenous vein as graft material for the construction of arteriovenous fistulas for use in haemodialysis. Fifty patients with PTFE grafts have been examined and compared with 70 patients with saphenous vein grafts. At eighteen months the accumulative patency rate was 69.8% for PTFE grafts and 68.9% for saphenous grafts. Although the PTFE grafts were similar in terms of patency, their complication rate was higher. The infection rate and distal ischaemia rate for PTFE grafts were double those of the vein grafts. Two patients developed median and ulnar nerve paralysis respectively shortly after implantation of PTFE grafts. Because of this it is recommended that their use be restricted to the lower limb. Despite a higher incidence of complications, PTFE grafts are a satisfactory substitute if a suitable saphenous vein is not available.     

POLYTETRAFLUOROETHYLENE (PTFE) GRAFTS FOR HAEMODIALYSIS: PATENCY AND COMPLICATIONS COMPARED WITH THOSE OF SAPHENOUS VEIN GRAFTS

A comparison has been made between polytetrafluoroethylene (PTFE) and saphenous vein as graft material for the construction of arteriovenous fistulas for use in haemodialysis. Fifty patients with PTFE grafts have been examined and compared with 70 patients with saphenous vein grafts. At eighteen months the accumulative patency rate was 69.8% for PTFE grafts and 68.9% for saphenous grafts. Although the PTFE grafts were similar in terms of patency, their complication rate was higher. The infection rate and distal ischaemia rate for PTFE grafts were double those of the vein grafts. Two patients developed median and ulnar nerve paralysis respectively shortly after implantation of PTFE grafts. Because of this it is recommended that their use be restricted to the lower limb. Despite a higher incidence of complications, PTFE grafts are a satisfactory substitute if a suitable saphenous vein is not available.     

A small arterial substitute: expanded microporous polytetrafluoroethylene: patency versus porosity.

Eighty-nine grafts of expanded microporous polytetrafluoroethylene (PTFE) with a diameter of 4 mm, were placed in the carotid and femoral arteries of dogs. The animals were sacrificed at varying intervals beginning three days after operation. Four animals remain alive with patent grafts 10 months post-operatively. Twenty-four of 89 grafts were occluded, an overall patency of 73%. Fibril length (pore size) of the graft material was varied from 4 to 110 microns. Average pore size ranged from 9 to 65 microns. Wall thickness varied from 0.3 to 0.75 mm. Density ranged from 0.24 to 0.35 g/ml. Tissue ingrowth, neointimization and patency rate as compared to pore size, wall-thickness and density of expanded PTFE were observed. Pore size is the primary determinant of tissue ingrowth, neointimization and patency. Of 51 grafts with an average pore size of 22 microns or less, there were 6 occlusions, an 88% patency rate. There were 38 grafts with an average pore size of 34 microns or greater. In these 38 grafts, 18 occlusions were observed, a 53% patency rate. Patent grafts demonstrated tissue ingrowth, capillary formation an a thin neointima. Using small pore grafts, patency rates of 90% can be anticipated in the dog. Expanded microporous PTFE with its ease of handling, strength and pliability may be the vascular prosthesis of choice in man.     

Fat- and bone marrow-impregnated small diameter PTFE grafts.

OBJECTIVES: to evaluate an alternative and simple technique which consists in impregnation of a synthetic prosthesis with either autogenic omental fat or bone marrow. These tissues have been selected based on previous works and because they contain multiple cellular and extracellular compounds with biological healing properties (i.e. angiogenesis, endothelialisation, etc.). DESIGN: PTFE grafts of Group 1 were impregnated with fatty tissue, those of Group 2 with bone marrow and those of Group 3 served as controls. MATERIALS: nine mongrel dogs divided among these three groups. PTFE grafts are 3 mm in diameter. METHODS: in each animal, both iliac arteries were submitted to an end-to-side ilio-iliac bypass. At 3 months, pathology assessment was performed. RESULTS: group 1: all grafts were thrombosed and intimal hyperplasia was found occluding the anastomotic sites. Group 2: 4/6 grafts were patent and their mid-portion presented a thin neointima which did not totally cover the anastomotic sites. Group 3: 2/5 grafts were patent and their mid-portion as well as the anastomotic sites were covered with neointima which was hyperplastic in some areas. CONCLUSIONS: addition of bone marrow cells may contribute to improve the quality of the healing process.     

Optimal prosthetic graft design for small diameter vascular grafts

Autogenous vein and arterial grafts, such as great saphenous veins and internal mammary and radial arteries, remain the gold standard conduits for vascular reconstruction. Expanded polytetrafluoroethylene (PTFE) grafts, which exhibit little inflammatory and thrombogenic reactivity, are the most commonly used material of choice for small diameter vascular grafts when autogenous grafts are not available. Several modifications of the basic graft have been attempted to enhance graft healing of expanded PTFE grafts, and little but definite experimental and clinical improvement has been achieved so far. The technique of vascular tissue engineering, in combination with stem cell research, may hold the key for the creation of a practical and successful small diameter prosthetic graft.     

Radionuclide study of platelets and prosthetic interactions: external versus specimen quantitation

Twenty-nine New Zealand white rabbits were allocated to undergo insertion of either polytetrafluoroethylene (PTFE) (n = 22) or microporous silicone rubber (SR) (n = 7), 3-mm diameter, 10-mm long aortic grafts. Animals with PTFE grafts received aspirin (ASA) 10 mg/kg/d and dipyridamole (DPM) 10 mg/kg/d (n = 11) or placebo (n = 11). Autologous In-111-oxine-labeled platelets were reinfused on reestablishment of blood flow through the graft. Using gamma camera images, an external graft platelet accumulation index (E-GPAI) was calculated as the In-111 activity in the graft area to the reference aorta at 24, 48, and 72 hours post implantation. Mean E-GPAI +/- SEM values for the ASA/DPM (n = 4) and control groups (n = 7) were 1.13 +/- 0.16 and 1.34 +/- 0.05 (NS) at 24 hours, 1.20 +/- 0.16 and 1.33 +/- 0.07 (NS) at 48 hours, and 1.38 +/- 0.07 and 1.35 +/- 0.10 (NS) at 72 hours, respectively. A similar internal graft platelet accumulation index (I-GPAI) was constructed based on In-111 activity in excised grafts and reference aorta measured in a scintillation counter. Mean I-GPAI +/- SEM values for the PTFE ASA/DPM (n = 9) and control groups (n = 8) at 48 hours post implantation were 43.1 +/- 2.7 and 216.8 +/- 73.9 (P = 0.05), respectively. I-GPAI values for the SR grafts were 192.5 +/- 43.1. Conclusion: The E-GPAI was not sensitive enough to demonstrate the effect of antiplatelet medication on platelet accumulation on the PTFE grafts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preservation of compliance in a small diameter microporous, silicone rubber vascular prosthesis

Compliance is believed to be a significant factor in maintaining the patency of small diameter vascular grafts. This study evaluated the compliance changes with time of microporous Replamineform silicone rubber prostheses. The compliance of 15 canine femoral artery interpositions (4 mm internal diameter X 6 cm length) was measured by in-vivo electromagnetic rheoangiometry immediately following implantation and at intervals to eight months. At implantation, silicone rubber grafts were overcompliant (15.0 +/- 1.1% radial change/mmHg X 10(-2); mean +/- S.E.) compared to the proximal artery (7.7 +/- .6%). The compliance of the prostheses decreased within two weeks (6.3 +/- .9%) and remained isocompliant to the proximal artery for eight months. The compliance determinations for the silicone rubber grafts were compared with those from PTFE prostheses and vein grafts acquired by the same method in a previous study. The analysis demonstrates the preservation of isocompliance of the silicone rubber prostheses compared to the native arteries. In contrast, the minimally compliant vein grafts and PTFE prostheses continued to decrease in compliance following implantation. This microporous silicone rubber graft may improve the success of small internal diameter arterial reconstructions by eliminating failures caused by compliance mismatch between the artery and the prosthesis.     

小径微孔聚氨酯人工血管的制备条件对微观结构与性能的影响

目的　研究小径微孔聚氨酯 (polyurethane,PU)人工血管的制备条件对微观结构和力学性能的影响。　方法　采用浸渍 -沥滤法制备 PU小径微孔人工血管 ,通过改变模径、PU材料、盐粒大小、盐胶比和浸渍次数等制备条件 ,控制人工血管的尺寸参数和微观结构 ,测定 PU血管的力学性能 ,观察血管尺寸参数和微观结构对其性能的影响。　结果　 PU小径血管内径 2～ 4 mm,壁厚 0 .6～ 1.2 mm,密度 0 .2 3～ 0 .4 9g/ cm3,孔径 4 2～ 95μm,孔隙率5 6 %～ 80 %。血管的径向顺应性 1.2 %～ 7.4 %· 13.3k Pa- 1 ,水渗透性 0 .2 9～ 12 .4 4 g/ (cm2 · min) ,轴向抗张强度1.5 5～ 4 .36 MPa,爆破强度 6 0～ 30 0 k Pa,缝线撕裂强度 19.5～ 96 .2 N/ cm2 。相同尺寸时 ,Chro- noflex制备的小径血管的顺应性和水渗透性优于 PCU- 15 0 0制备的小径血管 ,而 PCU- 15 0 0小径血管的轴向抗张强度、爆破强度和缝线撕裂强度优于 Chro- noflex小径血管。　结论　通过选择材料和优化制备条件 ,可制得具有合适孔径和孔隙率 ,顺应性和其它性能与天然血管匹配的 PU小径血管。     

Histological findings of tendon-bone healing following anterior cruciate ligament reconstruction with hamstring grafts

BACKGROUND: The purpose of the study was the histological examination of tendon-bone healing of hamstring grafts after anterior cruciate ligament (ACL) reconstruction. METHODS: During five arthroscopies done 6-14 months after ACL reconstructions, biopsies of the wall of the former drilled femoral canal were obtained. Four patients were primarily operated on using a suspending device (Endobutton, Acufex Microsurgical, Mansfield, MA, USA, and Transfix, Arthrex, Naples, FL, USA) for femoral fixation, one patient was reconstructed with a biodegradable interference screw directly inserted between the tendon and the wall of the canal. Biopsies were obtained using a tube harvester during re-arthroscopy. Three grafts were stable, two grafts were unstable, and revision of the ACL was performed. RESULTS: Histologically, in the four cases of reconstruction with a button or a rectangular pin, biopsies resembled granulation tissue without insertion of fibers between the tendon tissue and the bony wall. A wide area of woven bone was noted adjacent to the pre-existing lamellar bone. In contrast, the tendon-bone junction in the knee reconstructed with a biodegradable interference screw resembled a zone of metaplastic fibrous cartilage between the tendon graft and the lamellar bone. Collagen fibers connecting the tendon-bone interface occurred under polarized light microscopy. CONCLUSION: We conclude that the use of hamstring grafts for ACL reconstruction can lead to different histological pattern of tendon-bone healing. Micromotion of the hamstring graft inside the drilled canal can be play a role in tendon-bone healing.     

HERNIA UTERUS INGUINALE ASSOCIATED WITH UNILATERAL RENAL AGENESIS

We report a patient with a rudimentary uterine horn, fallopian tube and ovary in an inguinal hernia. Associated with this abnormality the patient had ipsilateral renal agenesis and a unicornuate uterus.