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PubMed2000

The effect of intramedullary bone plug on femoral stem migration of hydroxyapatite-coated hip arthroplasty.

This study investigated the effect of intramedullary corticocancellous bone plug on the fixation and stability of hydroxyapatite-coated femoral stems in total hip arthroplasty (THA). Intramedullary corticocancellous bone plug was used in 30 patients with hydroxyapatite-coated femoral stems (group A) and a consecutive series of 30 patients with hypdroxyapatite-coated stems without bone plug served as the control group (group B). Patients underwent clinical and radiographic follow-up for at least 2 years. The addition of corticocancellous bone plug to the hydroxyapatite-coated stem significantly improved clinical and radiographic results. The mean Harris Hip Score at 3 and 6 months postoperatively was 92 and 94 in group A, and 84 and 87 points in group B (P<.004 and P<.001, respectively). There was no significant difference between groups at 1 year postoperatively and thereafter. The predominant cause for the difference was the thigh pain score, which was reduced at both 3 and 6 months in group A compared to group B (P<.01 and P<.05, respectively). There also were statistical differences between the two groups regarding radiographic signs. The evidence of endosteal bone formation in group A patients was superior at 3 and 6 months (P<.001 and P<.01, respectively). The appearance of a radiolucent line was significant in group B patients at 3 and 6 months (P<.001). Femoral stem migration of 3 mm was noted in three group B patients versus no group A patients (P<.05). These short-term clinical and radiographic results suggest corticocancellous bone plug can provide early pain relief and durable implant fixation, but long-term follow-up should be considered.

Aged↗
PubMed1999

Hydroxyapatite as a bone substitute.

A bone substitute eliminates the need for autogenous and allogeneic bone grafting, along with the complications unique to each. Coralline hydroxyapatite is a synthetic bone void filler manufactured from marine coral, which has a natural trabecular structure similar to that of cancellous bone. While initial studies have been promising, the use of coralline hydroxyapatite may be limited in the foot and ankle owing to its inherent mechanical weakness and lack of biodegradation. In this retrospective study, 20 patients who received coralline hydroxyapatite implants were reviewed to determine associated complications and host reaction to the material. The results indicate that the material is biologically inert and safe to use as a small-defect filler in low-load applications. Long-term clinical trials are needed to determine the indications for this material in the foot and ankle.

Adult↗
PubMedDate not supplied

Tomodensitometric and histologic evaluation of the combined use of a collagen membrane and a hydroxyapatite spacer for guided bone regeneration: a clinical report.

In this report, the problems of insufficient bone and soft tissue after extraction of maxillary incisors were addressed concurrently prior to endosseous implant placement, by combining the use of a diphenylphosphorylazide-cross-linked Type I collagen membrane and a resorbable space-making biomaterial composed of 200-micron porous hydroxyapatite granules blended in Type I collagen and chondroitin-4-sulfate. Upon flap reflection 8 months postsurgery, the horizontal deficiencies were almost completely resolved, membranes completely resorbed and the defects filled with hard, bonelike tissue, with a few superficial hydroxyapatite granules. Histologic evaluation of the bone biopsies obtained at the implantation sites revealed dense, well-reconstructed alveolar bone with a few traces of hydroxyapatite granules that had been completely resorbed. Tomodensitometric evaluation indicated that bone regeneration ranged from 14% to 58%, with an average bone gain of 29.77%. Four nonsubmerged ITI titanium implants placed in the augmented bone have been in function for more than 5 years, with no clinical or radiographic signs of hard or soft tissue breakdown. Bacterial sampling at dental sites with periodontitis 1 month prior to periodontal therapy and at implant sites for up to 30 months demonstrated rapid colonization of implant surfaces by periodontopathogens without causing any detrimental effect to implant integration.

Absorbable Implants↗
PubMedDate not supplied

Efficacy of Chitra granule and powder (hydroxyapatite) in alveolar bone regeneration in rabbits. A histological evaluation.

The reconstruction or restoration of osseous defects caused by inflammatory periodontal disease is a continuing challenge in periodontal therapy. Great strides are being made to this effect using alloplasts such as hydroxyapatite. The present study was designed in Newzealand dwarf rabbits to observe the biologic response of periodontal tissues to synthetically prepared hydroxyapatite in both powder and granule forms by Srichitra Tirunal Institute for Medical Sciences & Technology, Trivandrum and to compare it with that of a commercially available, pure resorbable hydroxyapatite, OsteoGen (HA Resorb). The test materials were implanted in the artificially created bonydefects in the mandible via an intraoral approach. The wounds were allowed to heal upto 26 weeks postimplantation. The clinical evaluation at 12 weeks and 26 weeks postimplantation revealed neither any evidence of inflammation, infection or abscess formation nor any exposure or exfoliation of test materials. The histological examination of the implant sites at 12 and 26 weeks postimplantation revealed varying extent of formation of new osseous tissue and periodontal fibers. A comparison between test materials and control suggested that Chitra granules exhibit a relatively greater potential for newbone and periodontal fibre formation.

Alveolar Bone Loss↗
PubMedDate not supplied

Histologic evaluation of hydroxyapatite-coated root-form implant retrieved after 7 years in function: a case report.

This case report presents a clinical, radiographic, and histologic evaluation of 2 non-adjacent, hydroxyapatite-coated, root-form implants retrieved from the maxillary canine area of a patient after 7 years in function. Clinical examination revealed immobile implants with no sign of pathosis. Radiographic examination indicated close proximity of the bone to the implant surface without evidence of radiolucency. Histologically, the 2 implants appeared to be well integrated with the surrounding bone; 84% of the surface of the first implant and 79% of the surface of the second implant had close bone apposition at the interface. There was no evidence of dissolution of the hydroxyapatite coating. The bone appeared to be in immediate contact with the coating. These observations suggest that a particular hydroxyapatite coating on root-form implants can resist degradation during long-term function.

Aged↗
PubMed2000

Radiographic comparison of grit-blasted hydroxyaptite and arc-deposited hydroxyapatite acetabular components. A four-year follow-up study.

High rates of aseptic loosening have been reported for microstructured hydroxyapatite-coated acetabular components. A macrostructured component surface (arc-deposition) not only improves resistance to shear forces experienced by the acetabular component and increases initial stability, but also provides channels for bone ingrowth. The purpose of this investigation was to radiographically compare a series of grit-blasted (microstructured) and arc-deposited (macrostructured) hydroxyapatite-coated acetabular components. A minimum 4-year retrospective radiographic analysis of acetabular components was performed on a total of 50 total hip arthroplasties. At 4 years, arc-deposited components were associated with fewer radiolucent lines in all Charnley zones, particularly Charnley zone III. While the 4-year results for arc-deposited hydroxyapatite acetabular components are superior to their microstructured predecessors, long-term results are still unknown.

Acetabulum↗
PubMed2000

[Functional results in the reconstruction of the ossicular chain in partial or total atrophy of the incus. Comparison between reconstruction using a moulded incus and hydroxyapatite PORP].

Ossicular chain defects modifying sound transmission through the middle ear can be treated with (re)implantation of remodeled autologous o homologous ossicles. In recent years, thanks to improved biocompatibility of the materials on the market, prostheses have been increasingly used in the partial or total ossicular chain reconstruction. The present study evaluates auditory ossicle reconstruction as a result of partial or total atrophy of the incus, comparing the use of the remodeled autologous incus with the use of partial hydroxyapatite prostheses (PORP). The study involved 79 patients of which 59 (74.7%) underwent ossicular chain reconstruction using a remodeled, inverted autologous incus while in the remaining 20 cases (25.3%) a hydroxyapatite prosthesis (PORP) was used. The effectiveness of the ossicular chain was evaluated by comparing pre- and postoperative audiometry and evaluating the average thresholds at frequencies of 0.5, 1, 2 and 3 KHz. The average preoperative audiometric gap (understood as the relationship between the air-bone gap) was 23 dB (Standard Deviation 11.2) while postoperatively it was 11 dB (SD 8.5) (p < 0.0001). Therefore the improvement in the air-bone gap was 12 dB (SD 11) for the overall population: 13 dB (SD 10) in those cases where reconstruction was performed using a remodeled incus and 8 dB (SD 11) when PORP was used. The postoperative cumulative gap between the air and bone pathways fell between 0 and 20 dB in 84% of the total population: 89% of those reconstructed with a remodeled incus and 73% of those using PORP. The middle ear ossicular chain reconstruction was performed using remodeled, inverted autologous incus in those cases where ossicular damage did not compromise its use while prostheses made of a biocompatible material (hydroxyapatite PORP) were reserved for those cases where the incus was absent or severely worn. The results obtained are satisfactory, remained stable in time and reflect the average values reported in the Literature.

Adolescent↗
PubMed2001

Hydroxyapatite cranioplasty in fibrous dysplasia of the skull.

We describe the case of a woman who had complained of worsening headache during the previous year. Analysis of computed tomography imaging and biopsy led to a diagnosis of fibrous dysplasia of the skull. A symptomatic frontal bone lesion was removed, and the resulting defect was repaired with hydroxyapatite cement. Hydroxyapatite cement has several advantages over hydroxyapatite ceramic blocks and granules, and it is particularly well suited for calvarial reconstruction.

Adult↗
PubMed2000

[Application of polyester fiber heart patches to secondary intraorbital implantation of hydroxyapatite spheres].

OBJECTIVE: To observe the effect of intraorbital implantation of hydroxyapatite spheres wrapped with polyester fiber heart patches. METHOD: According to the rectus contraction points four rectus were found and the rectus valves were created in anophthalmos. Then the hydroxyapatite sphere wrapped by the polyester fiber heart patch was inserted in the orbit. RESULT: There were 13 cases in this group. Of them 11 patients showed very good operative results, Local poor healing of bulbar conjunctiva and fascia occurred in 2 patients. The wound in one patient healed very well after a simple repairing operation and in the other the wound healed spontaneously without any special treatments. CONCLUSION: The effect of secondary intraorbital implantation of hydroxyapatite spheres wrapped by polyester fiber heart patches is positive. The polyester fiber heart patch is safe, reliable, cheap, very convenient in use and easy to obtain. It is a better substitute for sclera which is used to wrap the HA sphere.

Adult↗
PubMed2000

[Human umbilical cord used for wrapping hydroxyapatite orbital implant--animal experiment and clinical observation].

OBJECTIVE: Hydroxyapatite (HA) sphere is admitted to be the best orbital implant today, but it can cause some complications, such as conjunctival erosion and implant exposure. The causes of these complications include HA's mechanical and chemical stimulation to the conjunctiva. In order to protect conjunctiva against HA's invasion, most authors suggest wrapping the HA sphere with some material. The wrapping materials usually are autogenous or heterogeneous sclera or fascia. These materials are either unavailable or unaccepted by patients. This study was made on human umbilical cord tissue as the wrapping material of HA sphere. METHOD: Hydroxyapatite spheres enveloped in human umbilical cord tissue were inserted in ten rabbits' orbits. At 1, 2 weeks and 1, 2, 3, 6, 8, 10, 12 and 14 months after implantation, the conjunctival sac was examined. Then the HA sphere was removed and examined with a scanning electron microscope. Fifteen patients received HA orbital implants enveloped in human umbilical cord from September 1996 To December 1997. The pre- and post-operative photographs of the sockets, the implant motility were analysed. RESULTS: The animal experiment showed that the umbilical cord was tightly adherent to the HA sphere and orbital tissue. The fibro-vascular tissue gradually invaded the interconnecting pores of the sphere after implantation. None of the 15 patients had orbital infection or implant extrusion during an average follow-up of 10 months (range of 8-12 months). Three patients had conjunctival erosion, which was well treated. All patients have cosmetically satisfactory motility of the prosthesis. CONCLUSION: Human umbilical cord tissue can be used as wrapping material of hydroxyapatite orbital implant.

Adolescent↗
PubMed2002

[Manufacture of hydroxyapatite as a defluoridator and the mechanism of defluoridation for drinking water].

Hydroxyapatite as a defluoridator for drinking water is characterized by a large capacity of defluoridation, and easy and simple operation in application. The quality of drinking water is not changed, the sorbent is easy to be regenerated, and the second pollution does not occur after the treatment of drinking water with the sorbent. Hydroxyapatite method has advantage over the methods such as actived alumina, bone char and electrodialysis commonly used in defluorination of drinking water. It is for this reason that the components, structural feature, synthesis and application of hydroxyapatite and its mechanism of defluoridation are summarized in this paper.

Durapatite↗
PubMed2001

[Study on the defluoridation of drinking water with synthetic hydroxyapatite].

Synthetic hydroxyapatite was used as a material for the defluoridation of drinking water. The defluoridation capacity, regeneration the capability of defluoridator and the corresponding parameters of defluoridation and regeneration have been studied with batch and column test. The results showed that the defluoridation capacity of synthetic hydroxyapatite on F- was 3.7-4.3 mg/g in batch test, 5.6 mg/g for break through (1.0 mg/L is considered as the break through point) in column test, and 10.7 mg/g for saturation in column test. The efficiency of regeneration was 46%-64% for saturated hydroxyapatite with surface-coating method.

Durapatite↗
PubMed2004

[The reason and management of the sunken upper eyelid after hydroxyapatite platform implantation].

OBJECTIVE: To study the reason and the management of the sunken upper eyelid after implanting a hydroxyapatite platform. METHODS: From 1998, we developed a method of subperiosteal implantation at the orbital floor to repair the introcession of the upper eyelid after hydroxyapatite platform implantation. 11 cases of the sunken upper eyelid were treated with this method. The implants included Medpor in 2 cases, hydroxyapatite plates in 7 cases and acellular dermal matrix in 2 cases. RESULTS: Postoperatively, all the patients obtained satisfactory results. Follow-up for 1 to 4 years showed no complications of extrusion or infection of the implants. Re-operation was needless in all of them. CONCLUSION: Subperiosteal implantation to correct the sunken upper eyelid is a safe and effective method.

Adult↗
PubMed2004

[Validity of bone scintigraphy for the diagnosis of periprosthetic complications in hydroxyapatite-coated total hip arthroplasty].

PURPOSE OF THE STUDY: To evaluate the efficacy and usefulness of 99Tc-MDP bone scans for the diagnosis of complications associated with hydroxyapatite- coated total hip prostheses. MATERIAL AND METHODS: 99Tc-MDP bone scans of 42 hips were taken before revision surgery in 41 patients with ABG 1 prostheses. Of these, 26 patients (27 hips) were included in our study on the basis of the following criteria: at least 23 months between the index surgery and scintigraphic examination and the availability of good quality bone scans. The average patients' age at the time of index and revision operations was 45.3 years (range, 32-57; SD, 6.02) and 50.2 years (36-61; SD, 6.01), respectively. The average time between the index surgery and bone scintigraphy was 50.3 months (23-84; SD, 15.9). Two experienced specialists in nuclear medicine, who were unaware of any clinical conclusions, participated in the study. RESULTS: Pre- and intra-operative findings showed aseptic loosening in three cups (3/27, 11 %) and one stem (1/27, 4 %). Four hips were suspected to have an infection on the basis of the positive results of intra-operative culture. In the diagnosis of aseptic loosening, sensitivity, specificity, accuracy, and positive and negative predictive values of bone scintigraphy were 100 %, 57 %, 62 %, 23 %, and 100 %, respectively, for the ABG I cup and 100 %, 52 %, 54 %, 8 %, and 100 %, respectively, for the ABG I stem. These characteristics were 67 %, 96 %, 93 %, 67 %, and 96 %, respectively, for the ABG I cup, when plain X-ray was used for evaluation of aseptic loosening. Specificity, accuracy and negative predictive value of plain X-ray for ABG I stem aseptic loosening were 100 %, 96 %, and 96 %. Bone scintigraphy gave one false positive result of sepsis; on the other hand, none of the four hips with positive intraoperative culture was diagnosed as septic. DISCUSSION: The fact that 99Tc-MDP bone scintigraphy as a method of diagnosing periprosthetic complications has a high sensitivity and a relatively low specificity has often been discussed in the literature. Currently, there are only a few studies on bone scintigraphy investigations of hydroxyapatite-coated prostheses. Some authors report that a slight increase in peri-prosthetic radionuclide activity may persist for up to 8 years which can explain the problematic accuracy of the technique. CONCLUSIONS: 99Tc-MDP bone scintigraphy is an intermediate useful tool for detecting complications of total hip arthroplasty with hydroxyapatite- coating. A negative bone scan almost always suggested the absence of aseptic loosening. However, the value of a positive result was regarded as controversial for the diagnosis of both aseptic and septic complications.

Adult↗
PubMed2005

Vertebral body reconstruction with injectable hydroxyapatite cement for the management of unstable thoracolumbar burst fractures: a preliminary report.

The aim of this prospective study was to evaluate the efficacy of an injectable hydroxyapatite cement in combination with long posterior transpedicular instrumentation, without fusion, for the treatment of unstable thoracolumbar burst fractures. Ten patients with this type of fracture were treated in the period 1999-2000 with bisegmental posterior transpedicular stabilisation above and below the fracture site, indirect reduction of the fracture, and transpedicular injection of hydroxyapatite cement into the fractured vertebral body. Postoperatively the mean Cobb kyphotic deformity angle (CKDA) and vertebral compression index (VCI) were statistically improved (p < 0.001). Both variables deteriorated slightly between surgery and follow-up after +/- 39 months; this was statistically not significant for the CKDA (p > 0.05), but significant for the VCI (p < 0.001). These data suggest that hydroxyapatite cement can be a reliable way to reinforce the fractured vertebral body in the thoracolumbar region.

Adult↗
PubMed2005

Bone graft substitute using hydroxyapatite scaffold seeded with tissue engineered autologous osteoprogenitor cells in spinal fusion: early result in a sheep model.

Spinal fusion using autologous bone graft is performed in an increasing rate for many spinal disorders. However, graft harvesting procedure is associated with prolonged operation time and potential donor site morbidity. We produced an engineered 'bone graft' substitute by using porous hydroxyapatite (HA) scaffold seeded with autologous bone marrow osteoprogenitor cells (OPCs) and fibrin. This obviates bone graft harvesting, thus eliminates donor site morbidity and shortens the operation time. The aim of this study is to evaluate Hydroxyapatite (HA) ceramics as scaffold for autologous tissue engineered bone construct for spinal fusion in a sheep model. The sheep's marrow was aspirated from iliac crest. The bone marrow mesenchymal stem cells (BMMSCs) were cultured for several passages in the presence of growth and differentiation factors to increase the number of OPCs. After the cultures reached confluence, they were trypsinized and seeded on Hydroxyapatite scaffold (HA). Approximately 5 million cells were generated after 3 weeks of culture. Microscopically, very tight Colony Forming Units (CFU-Fs) were seen on monolayer culture. The Von Kossa and Alizarin Red staining of monolayer culture showed positive mineralization areas; indicating the presence of OPCs. Sheep underwent a posterolateral spinal fusion in which scaffolds with or without OPCs seeded were implanted on both sides of the lumbar spine (L1-L2). Intended fusion segments were immobilized using wires. At the end of third month, the fusion constructs were harvested for histological examination. Fibrous tissue infiltration found in the inter-connecting pores of plain HA ceramics indicates inefficient new bone regeneration. New bone was found surrounding the HA ceramics seeded with autologous cells. The new bone is probably formed by the sheep BMMSCs that were initially encapsulating HA while it remained intact. The new bone is naturally fused with the vertebrae. In conclusion, the incorporation of autologous bone marrow cells improved the effectiveness of HA ceramics as 'bone graft' substitute for spinal fusion.

Animals↗
PubMed2006

Lower serum calcium levels are associated with greater calcium hydroxyapatite deposition in native aortic valves of male patients with severe calcific aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the relationship between serum calcium levels and the degree of calcification found in stenotic aortic valves. METHODS: Using atomic absorption spectroscopy, the hydroxyapatite content of 228 excised human stenotic aortic valves was determined and expressed as a percentage of valve mass. Left heart catheterization preceded valve replacement. In addition, serum levels of calcium and creatinine were determined before native calcific aortic valve excision. RESULTS: Valves from male patients contained more hydroxyapatite than those of female patients (26 +/- 9 versus 22 +/- 9 mass%; p < 0.001). Patients presenting with lower serum calcium levels showed a slight trend towards higher levels of valve calcification (r = -0.15, p = 0.026), but this association appeared only within the subgroup of male patients. Male patients with lowest serum calcium levels displayed greatest valvular hydroxyapatite deposition (1st calcium tertiary: 29.5 +/- 8.9 mass% versus 2nd calcium tertiary 26.4 +/- 7.8 mass% versus 3rd calcium tertiary 21.4 +/- 8.9 mass%; n = 122; p = 0.001; r = -0.25; p = 0.006). This association was even more distinct in male patients with normal serum creatinine levels. Furthermore, serum calcium was inversely and significantly associated with serum C-reactive protein in male patients (r = - 0.34; p < 0.001). CONCLUSION: Serum calcium levels appear to be inversely related to valve calcification in patients with severe calcific aortic stenosis (AS). This finding indicates the importance of systemic calcium metabolism in calcific AS, independent of manifest disorders of calcium metabolism or renal function. Interestingly, this association was evident only in male patients, suggesting a gender-dependent pathogenesis.

Aged↗
PubMedDate not supplied

Interface analysis of hydroxyapatite-coated implants in a human vascularized iliac bone graft.

This case report demonstrates the interface histology of hydroxyapatite-coated dental implants placed in a human vascularized iliac bone graft. Microscopic evaluation found a direct contact of lamellar bone to the implant surface even in areas of loose trabeculation. The hydroxyapatite coating was intact, with no evidence of resorption. This study appears to show that the healing response to hydroxyapatite-coated implants placed in vascularized bone grafts is similar to previously reported findings in nongrafted sites.

Aged↗