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1.
J Bone Joint Surg Br ; 93(6): 760-8, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21586774

ABSTRACT

Four uncemented Symax hip stems were extracted at three weeks and nine, 13 and 32 months, respectively, for reasons other than loosening. The reasons for implant removal were infection in two cases, recurrent dislocation in one and acetabular fracture in one. They were analysed to assess the effect and behaviour of an electrochemically deposited, completely resorbable biomimetic BONIT-hydroxyapatite (HA) coating (proximal part) and a DOTIZE surface treatment (distal part) using qualitative histology, quantitative histomorphometry and scanning electron microscopy (SEM). Early and direct bone-implant bonding with signs of active remodelling of bone and the HA coating were demonstrated by histology and SEM. No loose BONIT-HA particles or delamination of the coating were observed, and there was no inflammation or fibrous interposition at the interface. Histomorphometry showed bone-implant contact varying between 26.5% at three weeks and 83.5% at 13 months at the HA-coated implant surface. The bone density in the area of investigation was between 24.6% at three weeks and 41.1% at 32 months. The DOTIZE surface treatment of the distal part of the stem completely prevented tissue and bone apposition in all cases, thereby optimising proximal stress transfer. The overall features of this implant, in terms of geometry and surface texture, suggest a mechanically stable design with a highly active biomimetic coating, resulting in rapid and extensive osseo-integration, exclusively in the metaphyseal part of the stem. Early remodelling of the HA coating does not seem to have a detrimental effect on short-term bone-implant coupling. There were no adverse effects identified from either the BONIT-HA coating or the DOTIZE surface treatment.


Subject(s)
Coated Materials, Biocompatible , Hip Prosthesis , Osseointegration/physiology , Aged , Arthroplasty, Replacement, Hip , Biomimetic Materials , Bone Density/physiology , Durapatite , Female , Femur/pathology , Femur/physiopathology , Humans , Male , Microscopy, Electron, Scanning , Middle Aged , Osteoarthritis, Hip/surgery , Prosthesis Design , Prosthesis Failure , Surface Properties
2.
Foot Ankle Int ; 28(5): 537-41, 2007 May.
Article in English | MEDLINE | ID: mdl-17559759

ABSTRACT

BACKGROUND: The degree of correction of hallux valgus deformity using a distal chevron osteotomy is reported as limited. The scarf osteotomy is reported to correct large intermetatarsal angles (IMA). The purpose of this study was to evaluate if one technique gave greater correction of the IMA and hallux valgus angle (HVA) than the other. METHODS: After informed consent, 96 feet in 83 patients were randomized into two treatment groups (49 scarf and 47 chevron osteotomies). The results were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) Hallux Valgus Scale and radiographic HVA and IMA measurements. RESULTS: At 27 (range 23-31) months followup both groups improved. The AOFAS score in the chevron group improved from 48 to 89 points and in the scarf group from 47 to 91 points. In the chevron group the HVA corrected from 30 to 17 degrees, and in the scarf group the HVA corrected from 29 to 18 degrees. In both groups, the IMA was corrected from 13 to 10 degrees. The differences were not statistically significant. Three patients in the chevron group developed a partial metatarsal head necrosis. In the scarf group, four patients developed grade 1 complex regional pain syndrome compared to one patient in the chevron group. CONCLUSIONS: No differences of statistical significance could be measured between the two groups with respect to the AOFAS score, HVA, and IMA. Although both groups showed good to excellent results, we favor the chevron osteotomy because the procedure is technically less demanding.


Subject(s)
Hallux Valgus/surgery , Osteotomy/methods , Adult , Female , Humans , Middle Aged , Osteotomy/adverse effects , Treatment Outcome
3.
J Bone Joint Surg Br ; 81(4): 710-8, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10463751

ABSTRACT

We performed a prospective, randomised double-blind study in 24 patients undergoing high tibial osteotomy to evaluate the effectiveness of human recombinant osteogenic protein (OP-1) on a collagen type-I carrier in a critically-sized fibular defect. The study had two phases, each evaluated by clinical, radiological and DEXA methods during the first postoperative year. The first concerned the validation of the model of the fibular defect, using positive (demineralised bone) and negative (untreated) controls. The second phase concerned the osteogenic potential of OP-1 on collagen type-I v collagen type-I alone. The results of the first phase established the critically-sized nature of the defect. In the untreated group no bony changes were observed while, in the demineralised bone group, formation of new bone was visible from six weeks onwards. The results of the second phase showed no significant formation of new bone in the presence of collagen alone, while in the OP-1 group, all patients except one showed formation of new bone from six weeks onwards. This proved the osteogenic activity of OP-1 in a validated critically-sized human defect.


Subject(s)
Bone Morphogenetic Proteins/therapeutic use , Fibula/pathology , Osteogenesis , Transforming Growth Factor beta/therapeutic use , Adult , Aged , Bone Morphogenetic Protein 7 , Double-Blind Method , Female , Humans , Male , Middle Aged , Prospective Studies , Recombinant Proteins
4.
J Bone Joint Surg Am ; 80(8): 1175-85, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9730127

ABSTRACT

We evaluated 377 patients (428 hips) who had been managed, by a total of fourteen surgeons at twelve clinical sites in the United States and Europe, with a porous-coated press-fit acetabular cup, a hydroxyapatite-coated threaded screw-in cup, or one of two similar designs of hydroxyapatite-coated press-fit cups between April 1987 and November 1992. The same type of hydroxyapatite-coated femoral stem was inserted without cement in all patients. After a minimum duration of follow-up of five years (mean, 7.9 years; range, 5.3 to 9.1 years), one (1 per cent) of the 131 hydroxyapatite-coated threaded cups, two (2 per cent) of the 109 porous-coated press-fit cups, and twenty-one (11 per cent) of the 188 hydroxyapatite-coated press-fit cups had been revised because of aseptic loosening. A common radiographic sign of impending failure of the hydroxyapatite-coated press-fit cups was radiolucency at the interface between the implant and the subchondral bone beneath it. This radiolucency usually was seen initially more than two years after implantation. Radiographic evaluation of the 383 acetabular implants that were in situ at the time of the most recent follow-up showed that 123 (99 per cent) of the 124 hydroxyapatite-coated threaded cups, 101 (98 per cent) of the 103 porous-coated cups, and 139 (89 per cent) of the 156 hydroxyapatite-coated press-fit cups were stable with osseous ingrowth (as indicated by the absence of radiolucency at the interface and the absence of migration within the acetabulum). The probability of revision due to aseptic loosening was significantly greater for the hydroxyapatite-coated press-fit cups than it was for the hydroxyapatite-coated threaded cups or the porous-coated press-fit cups (p < 0.001 for both comparisons). Within the group of patients who had a hydroxyapatite-coated press-fit cup, the probability of revision due to aseptic loosening was significantly greater in association with a young age (p = 0.003), female gender (p = 0.02), the use of a femoral head with a diameter of thirty-two millimeters (p = 0.018), and the use of a thin polyethylene liner (p < 0.001). We found that the hydroxyapatite-coated threaded cups and the porous-coated press-fit cups continued to perform well more than five years after the operation. The hydroxyapatite-coated press-fit cups that were revised probably failed because the fixation interface beneath the cup could not sustain the tensile stresses that were imposed between the cup and the bone by the activity of the patient. Our data suggest that, in the specific biomechanical environment of the acetabulum, physical interlocking between the cup and the supporting bone beneath it may be a prerequisite for long-term stability.


Subject(s)
Arthroplasty, Replacement, Hip/methods , Acetabulum , Biomechanical Phenomena , Cementation , Female , Femur Head Necrosis/surgery , Follow-Up Studies , Humans , Hydroxyapatites , Male , Osteoarthritis, Hip/surgery , Prosthesis Failure , Reoperation , Treatment Outcome
5.
J Bone Joint Surg Br ; 80(3): 437-40, 1998 May.
Article in English | MEDLINE | ID: mdl-9619932

ABSTRACT

We describe six knees in five patients, referred to us after accidental irrigation with chlorhexidine 1% in aqueous solution during arthroscopy. All six knees developed persisting pain, swelling and crepitus with loss of range of movement. Radiographs showed loss of joint space in all three compartments due to extensive chondrolysis, with many loose bodies and synovitis. Histological examination showed partial necrosis of the cartilage, with slight non-specific inflammation and fibrosis of synovial specimens. Care is needed in checking irrigation fluids, and these should have a distinctive colour.


Subject(s)
Anti-Infective Agents, Local/adverse effects , Arthroscopy/adverse effects , Chlorhexidine/adverse effects , Knee Joint/drug effects , Adult , Cartilage Diseases/chemically induced , Cartilage Diseases/diagnostic imaging , Cartilage, Articular/diagnostic imaging , Cartilage, Articular/drug effects , Cartilage, Articular/pathology , Edema/chemically induced , Fibrosis , Humans , Joint Diseases/chemically induced , Joint Diseases/diagnostic imaging , Joint Diseases/physiopathology , Joint Loose Bodies/chemically induced , Joint Loose Bodies/diagnostic imaging , Knee Joint/diagnostic imaging , Knee Joint/physiopathology , Male , Necrosis , Osteochondritis/chemically induced , Osteochondritis/pathology , Pain/chemically induced , Radiography , Range of Motion, Articular/physiology , Synovitis/chemically induced , Synovitis/diagnostic imaging , Therapeutic Irrigation
6.
J Bone Joint Surg Br ; 78(6): 892-8, 1996 Nov.
Article in English | MEDLINE | ID: mdl-8951002

ABSTRACT

We have investigated the use of a conically-shaped cement plug made of Polyactive (PA), a biodegradable copolymer. The flexibility and hydrogel properties were thought to facilitate occlusion of the femoral canal even when it was oval or irregular in shape. The function of the plug was first compared with that of the Thackray polyethylene model in 16 artificial plastic femora. The maximum intramedullary pressure achieved during cementing was ten times higher with the biodegradable model. Migration or leakage of cement did not occur when the diameter of the femoral canal was equal to or smaller than the diameter of the plug. We also showed that the biodegradable properties of this implant were such that it did not require removal during revision. The new plug was tested in a pilot clinical trial. At two years only two out of 21 patients had evidence of migration or leakage of cement, probably due to a mismatch in the size of plug and femoral canal. There were no local changes in the femur.


Subject(s)
Biocompatible Materials/therapeutic use , Bone Cements/therapeutic use , Cementation , Hip Prosthesis/methods , Polyesters/therapeutic use , Polyethylene Glycols/therapeutic use , Humans
7.
J Bone Joint Surg Br ; 77(4): 534-47, 1995 Jul.
Article in English | MEDLINE | ID: mdl-7615595

ABSTRACT

We present the 5.6- to 7.6-year results of our first 118 hydroxyapatite (HA)-coated total hip replacements in patients under 66 years of age. The titanium femoral component has proximal HA coating and was usually articulated with an HA-coated threaded cup. The HA coating of 50 microns thickness has a porosity of below 3%, 97% HA purity and 65% crystallinity. The survival rate at a mean of six years was 100% for the HA-coated stems and 99% for the HA-threaded cups. The average Harris hip score at one year was 96, and at three years and thereafter 98. There was a very low incidence of early pain after surgery. Serial radiographs showed rapid bony integration of implants with evidence of bone apposition on the coating within six months. By Engh's criteria, all the femoral components had confirmed bone ongrowth after three years. We found no deterioration of results with time, and consider that our clinical and radiological results show that HA coatings can provide early pain relief and durable implant fixation.


Subject(s)
Hip Prosthesis , Hydroxyapatites , Osteoarthritis, Hip/surgery , Adult , Aged , Bone Density , Bone Remodeling , Evaluation Studies as Topic , Female , Humans , Male , Middle Aged , Postoperative Complications , Prosthesis Design , Retrospective Studies , Treatment Outcome
8.
Paris; Expansion Scientifique Française; 1995. xviii,376 p. ilus, tab, graf.
Monography in English | Coleciona SUS | ID: biblio-925198
9.
J Arthroplasty ; 8(2): 167-77, 1993 Apr.
Article in English | MEDLINE | ID: mdl-8386747

ABSTRACT

Histologic sections of five hydroxyapatite-coated acetabular components retrieved at autopsy (2 dual geometry and 3 threaded cup designs) were analyzed, and the extent and pattern of bone apposition were compared with that of an uncoated, porous (beaded) dual geometry acetabular cup that had been removed for repeated dislocations. The results show hydroxyapatite and bone apposition most prominent in areas of likely load transmission, primarily around the peripheral rim of the dual-geometry cups and at the peaks of the threads of the screw cups. Hydroxyapatite and bone may have been removed by remodeling from the grooves between the threads. Although no significant wear debris was identified, the screw holes were incompletely covered by bone. The dual-geometry designs generally showed somewhat more bone apposition than the threaded cups, but all implants demonstrated less bone than might have been predicted from radiographs.


Subject(s)
Hip Prosthesis , Hydroxyapatites , Osseointegration , Adult , Bone Cements , Bone Remodeling , Durapatite , Female , Humans , Male , Middle Aged , Photomicrography , Prosthesis Design , Reoperation
10.
Acta Orthop Belg ; 59 Suppl 1: 160-4, 1993.
Article in English | MEDLINE | ID: mdl-8116393

ABSTRACT

The favourable results of experimental HA-coated hip replacement are fully reflected in the clinical results of HA-coated total hip replacement, both in primary and revision arthroplasty. The radiologically visible osseointegration of virtually all cases is supported by histological proof in five autopsy retrieval hips. They show that HA-coatings are reliable in achieving good quality osseointegration over the majority of the implant surface in contact with the cortical bone. Longterm resorption of HA can be expected, however the quality of osseointegration is not influenced, because bone takes the place of the resorbed HA. An ideal pressfit situation is probably the long term outcome. Until six years postoperatively, there are no signs of either clinical or radiological loosening of HA-coated components.


Subject(s)
Bone and Bones/drug effects , Hip Prosthesis , Hydroxyapatites/pharmacology , Osseointegration/drug effects , Adult , Aged , Animals , Bone Remodeling , Bone and Bones/cytology , Dogs , Female , Follow-Up Studies , Humans , Male , Middle Aged , Prosthesis Failure
11.
J Orthop Res ; 10(1): 58-61, 1992 Jan.
Article in English | MEDLINE | ID: mdl-1727936

ABSTRACT

For the histopathological classification of the severity of osteoarthritic lesions of cartilage, the Mankin score is frequently used. A necessary constraint on the validity of this scoring system is the consistency with which cartilage lesions are classified. The intra- and interobserver agreement of the Mankin score was determined. The intra- and interobserver agreement of the 14-point Mankin score was adequate. Between observers 95% of differences were less than approximately 7 points. By a more strict definition of the elements of the Mankin score, the intraobserver differences were reduced only for some observers. The interobserver differences were only slightly reduced: between observers 95% of differences were less than approximately 6 points. We found the Mankin score to be an adequate histopathological tool.


Subject(s)
Osteoarthritis/pathology , Severity of Illness Index , Animals , Female , Observer Variation , Rabbits
12.
Clin Orthop Relat Res ; (261): 39-58, 1990 Dec.
Article in English | MEDLINE | ID: mdl-2245562

ABSTRACT

Studies of implant fixation have shown that hydroxyapatite (HA) coatings provide early and strong fixation to bone. This is a report of 100 consecutive cases of total hip arthroplasties, using HA coating, which were mainly for osteoarthrosis, avascular necrosis, or revision for failed implants. The average prospective follow-up period was two years. Titanium femoral components had a proximal HA coating, usually with an HA-coated screw cup. For both HA-coated components, the average Harris hip score was 96 points after one year and 98 after two years. Analysis of data shows that the incidence of pain was low immediately after surgery and at 4% one year postoperatively. There was no difference between the results of primary cases and revisions after the one-year interval. On roentgenographic examination, there was a rapid bony integration of implants with bone apposition on the coating within six months, accompanied by specific patterns of remodeling. No radiolucent line formation was detected around HA-coated implant parts. There were no revisions for loose implants. After two years, 97% of the patients had positive roentgenographic evidence of femoral ingrowth compared to 55% for HA-coated acetabular cups, with a statistical significance between bone ingrowth and clinical results. Implant fixation using HA coatings is a reliable procedure for good bony fixation and clinical results.


Subject(s)
Femur/growth & development , Hip Prosthesis , Hydroxyapatites/pharmacology , Osseointegration/drug effects , Adult , Aged , Female , Femur/diagnostic imaging , Femur/drug effects , Follow-Up Studies , Hip Joint/diagnostic imaging , Humans , Male , Middle Aged , Radiography , Reoperation
13.
Orthopedics ; 12(9): 1239-42, 1989 Sep.
Article in English | MEDLINE | ID: mdl-2552423

ABSTRACT

Published experimental studies have founded the principles of implant fixation using hydroxyapatite coatings. Clinical results are given on the first 100 consecutive cases of hydroxyapatite-coated total hip replacement performed since 1986. The Harris hip score rating at 1 year and longer is 98 and the specific radiologic characteristics are discussed.


Subject(s)
Hip Prosthesis , Hydroxyapatites , Animals , Bone and Bones/pathology , Dogs , Durapatite , Equipment Design , Follow-Up Studies , Hip Joint/diagnostic imaging , Humans , Materials Testing , Osteogenesis , Radiography
14.
J Bone Joint Surg Br ; 70(1): 17-22, 1988 Jan.
Article in English | MEDLINE | ID: mdl-2828374

ABSTRACT

Implants of solid sintered hydroxyapatite form very tight bonds with living bone, but are susceptible to fatigue failure. This problem can be overcome by using plasma-sprayed apatite coatings on titanium implants. A very strong bond is formed between bone and this composite material; this was studied in canine bone with plug implants, avoiding any mechanical retention. Mechanical testing showed an interface shear strength at six weeks of 49 MPa with a maximum of 64 MPa after six months. There was histological evidence of direct bonding between the apatite coating and living bone while uncoated control plugs were easily extracted. The results indicate that apatite-coated implants can form a chemical fixation with a strength comparable to that of cortical bone itself. This fixation is far stronger than that provided by current cemented or uncemented fixation techniques.


Subject(s)
Bone and Bones , Hydroxyapatites , Prostheses and Implants , Titanium , Adhesiveness , Animals , Bone and Bones/diagnostic imaging , Bone and Bones/pathology , Dogs , Durapatite , Hydroxyapatites/blood , Radiography , Stress, Mechanical , Surface Properties , Tensile Strength
15.
Clin Orthop Relat Res ; (225): 147-70, 1987 Dec.
Article in English | MEDLINE | ID: mdl-2824115

ABSTRACT

Sintered hydroxyl-apatite implants form very tight bonds with living bone but are susceptible to fatigue failure. Plasma-sprayed apatite coatings on titanium substrates overcome the fatigue problem. The static tensile substrate bond strength of the apatite coating is in excess of 85 megapascals (MPa) (12,000 psi). In a plug implant study designed to discount mechanical retention, a bone bonding shear strength of 64 MPa (9280 psi) was achieved, comparable to the strength of cortical bone. Histologic sections confirm the close bonding between apatite coating and living bone. In a canine total hip arthroplasty study, the apatite-coated implants proved far superior to the uncoated controls. Uncoated prostheses were surrounded by fibrous tissue and were easily extracted from the femur at any postoperative time. The apatite-coated implants were rigidly fixed within three weeks with demonstrable bone formation up to the implant surface. Bony defects up to 2 mm in depth were filled with bone within six weeks. The hypothetical mechanism of bone bonding is chemical. Hydroxyl-apatite coatings permit an implant fixation far superior to current methods using either cemented or cementless techniques. The plan is to study a human total hip prosthesis with hydroxyl-apatite coating for chemical fixation to bone.


Subject(s)
Bone and Bones/drug effects , Hydroxyapatites/pharmacology , Titanium/pharmacology , Animals , Bone and Bones/ultrastructure , Chemical Phenomena , Chemistry, Physical , Dogs , Durapatite , Femur/drug effects , Hip Prosthesis , Humans , Osteogenesis , Prostheses and Implants , Prosthesis Design , Tensile Strength
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