Zusammenfassung
Hintergrund: Die Beschichtung von Hüftendoprothesenschäften mit Hydroxylapatit (HA) wird mit dem
Ziel einer Verbesserung der Osseointegration durchgeführt. Ziel dieser retrospektiven
Studie war es, die radiologische Darstellung von neu gebildetem Knochen um beschichtete
Areale zu untersuchen. Von besonderem Interesse war die Dokumentation des frühpostoperativen
Verlaufs mittels monitorgezielten standardisierten Nativröntgenaufnahmen. Patienten und Methode: 40 unselektierte Patienten nach Primärimplantation (Durchschnittsalter 67,3 Jahre)
mit einem im proximalen Drittel HA-beschichteten Prothesenschaft wurden retrospektiv
nach durchschnittlich 1,3 Jahren sowie nach durchschnittlich 3,0 Jahren untersucht.
Monitorgezielte a.–p. sowie Axialaufnahmen wurden jeweils durchgeführt. Die periprothetischen
Regionen um das proximale Schaftende wurden hinsichtlich ossärer Strukturen sowie
auch Saumbildungen analysiert. Ergebnisse: Nach 1 Jahr fanden sich am Axialbild in 2 Fällen zarte, parallel zur Prothesenoberfläche
verlaufende Verdichtungen. Nach 3 Jahren waren diese wesentlich ausgeprägter und wurden
in mehr als 25 % der Fälle gesehen. Diese Knochenneubildungen, die der Prothese direkt
anlagen, waren auf die Länge der HA-Beschichtung beschränkt. Die Zahl der Saumbildungen
ging innerhalb dieser Zeit von 4 auf 1 zurück. Schlussfolgerung: Die postoperative Knochenneubildung an HA-beschichteten Prothesenoberflächen kann
am Röntgenbild verifiziert werden. Sie ist Ausdruck eines rasch erfolgenden Osseointegrationsprozesses
aufgrund der osseokonduktiven Eigenschaft des HA. Saumbildungen werden deshalb auf
ein Minimum reduziert. Die Beschichtung mit HA lässt somit eine Verbesserung der Stabilität
der Implantate in der unmittelbar postoperativen Phase sowie auch einen raschen Verschluss
der Markhöhle erwarten. Auswirkungen auf das Langzeitergebnis der Implantate können
somit angenommen werden.
Abstract
Background: To facilitate implant osseointegration in the early postoperative period, coating
of the implant surfaces with osseoconductive materials, e.g. hydroxyapatite (HA),
is being increasingly recommended. It apparently reduces the rate of radiolucent lines
and even improves the osseointegration of implants less well suited for cementless
anchorage. We analysed HA-coated stems to find out whether newly formed bone adherent
to the implant surface such as seen on explanted stems is also seen on radiographs
and whether it follows a specific morphological pattern. We also wanted to know whether
newly formed peri-implant bone extends over the entire length of the HA-coating, at
which point in time it is seen radiographically and whether it expands within the
first few years post implantation by radiological evidence. Patients and Method: Radiographs of 40 unselected patients after primary total hip arthroplasty (THR),
14 males and 26 females, aged 44.4 to 86.7 years at the time of THR, with a mean age
of 67.3 years were available for analysis. Monitor-guided a.–p. and axial views of
the stems were obtained in the early postoperative period up to 6 weeks post THR,
at a mean follow-up time of 1.3 (1.0 to 1.8) years and 3.0 (1.9 to 3.7) years. Tapered
straight stems with a rectangular cross-section made of a wrought Ti6AI7Nb alloy with
an HA coating in the proximal third were used. Results: A.–p. views: At one year there were no signs suggesting an increased ongrowth of
bone. At 3 years, on average, delicate bony appositions were seen on the implant surfaces
in position 1 in three stems, in one of them also in position 7. These looked like
a sclerotic zone lacking a sharp demarcation and were in direct contact with the implants
without any bone-to-implant gaps. Axial views: At about one year two stems showed
delicate bony appositions parallel to the implant surface in the proximal part in
positions 8 and 9 as well as 13 and 14. Named “miniscleroses” by us, these structures
were confined to the length of the HA coating. At three years these miniscleroses
were clearly visible around 11 stems (more than 25 %). Those already seen at one year
were much better defined at three years, but still confined to the HA-coated part
of the stem. Some of them were poorly demarcated from the adjacent bone and medullary
canal and some showed smooth demarcations. The density of the bony ongrowths was either
homogeneous or increased from the medullary space or adjacent bone towards the implant
surface. All of them were adherent to the implant surface. While not related to the
peri-implant cortical bone, they were in contact with trabecular structures. After
a mean follow-up time of one year radiolucent lines were seen around four stems in
positions 1, 7 and 8. These were up to 1 mm in size around two stems and 2 mm or more
in the other two. At 3 years all of the visible radiolucencies had disappeared except
for one measuring 1 mm in position 8. Conclusions: The structures we found radiographically apparently reflect newly formed bone along
the entire HA-coated implant surface. Most of them were located in positions 8, 9
and 13, 14. They provide visible evidence of osseointegration at osseoconductive surfaces.
As they apparently did not have any contact with the peri-implant bone, they appear
to be compatible with the bilateral osteogenesis according to Osborn. The effects
of the rapid bony ongrowth on HA-coated surfaces and the striking absence of radiolucencies
on the long-term outcome are still speculative. But the structures seen may be taken
as a sign of improved implant stability by rapid osseointegration and of early sealing
of the medullary canal. As a result, wear particles of the articulating surfaces are
barred from spreading to the medullary cavity of the femur. This alone argues in favour
of using coated implants throughout. However, more studies are needed to shed light
on these issues.
Schlüsselwörter
Hüftendoprothese - Hydroxylapatit - Knochenneubildung - radiologische Befunde
Key words
hip endoprosthesis - hydroxyapatite - bone formation - radiological findings
Literatur
- 1
Dohle J, Becker W, Braun M.
Radiological analysis of osseointegration after implantation of the Zweymüller-Alloclassic
total hip system.
Z Orthop.
2001;
139
517-524
- 2
Lintner F, Zweymüller K, Brand G.
Tissue reactions to titanium endoprostheses – autopsy studies in four cases.
J Arthroplasty.
1986;
1
183-195
- 3
Pieringer H, Auersperg V, Grießler W et al.
Long-term results with the cementless Alloclassic brand hip arthroplasty system.
J Arthroplasty.
2003;
18
321-328
- 4
Zweymüller K, Schwarzinger U, Steindl M.
Radiolucent lines and osteolysis along tapered straight cementless titanium hip stems:
a comparison of 6-year and 10-year follow-up results in 95 patients.
Acta Orthop.
2006;
77
871-876
- 5
Søballe K, Overgaard S.
The current status of hydroxyapatite coating of prostheses.
J Bone Joint Surg [Br].
1996;
78
689-691
- 6
Geesink R G, de Groot K, Klein C P.
Chemical implant fixation using hydroxyl-apatite coatings. The development of a human
total hip prosthesis for chemical fixation to bone using hydroxyl-apatite coatings
on titanium substrates.
Clin Orthop Relat Res.
1987;
225
147-170
- 7
Capello W N, D'Antonio J A, Jaffe W L et al.
Hydroxyapatite-coated femoral components: 15-year minimum followup.
Clin Orthop Relat Res.
2006;
453
75-80
- 8
Furlong R J, Osborn J.
Fixation of hip prostheses by hydroxyapatite ceramic coatings.
J Bone Joint Surg [Br].
1991;
73
741-745
- 9
Hamadouche M, Witvoet J, Porcher R et al.
Hydroxyapatite-coated versus grit-blasted femoral stems. A prospective, randomised
study using EBRA-FCA.
J Bone Joint Surg [Br].
2001;
83
979-987
- 10
Chambers B, St Clair S F, Froimson M I.
Hydroxyapatite-coated tapered cementless femoral components in total hip arthroplasty.
J Arthroplasty.
2007;
22
71-74
- 11
Dorr L D, Wan Z, Song M et al.
Bilateral total hip arthroplasty comparing hydroxyapatite coating to porous-coated
fixation.
J Arthroplasty.
1998;
13
729-736
- 12
Landor I, Vavrik P, Sosna A et al.
Hydroxyapatite porous coating and the osteointegration of the total hip replacement.
Arch Orthop Trauma Surg.
2007;
127
81-89
- 13
Kärrholm J, Malchau H, Snorrason F et al.
Micromotion of femoral stems in total hip arthroplasty. A randomized study of cemented,
hydroxyapatite-coated, and porous-coated stems with roentgen stereophotogrammetric
analysis.
J Bone Joint Surg [Am].
1994;
76
1692-1705
- 14
Tanzer M, Gollish J, Leighton R et al.
The effect of adjuvant calcium phosphate coating on a porous-coated femoral stem.
Clin Orthop Relat Res.
2004;
424
153-160
- 15
Steens W, Schneeberger A G, Skripitz R et al.
Bone remodeling in proximal HA-coated versus uncoated cementless SL-Plus® femoral
components: a 5-year follow-up study.
Arch Orthop Trauma Surg.
2010;
130
921-926
- 16
Kroon P O, Freeman M.
Hydroxyapatite coating of hip prostheses. Effect on migration into the femur.
J Bone Joint Surg [Br].
1992;
74
518-522
- 17
Søballe K, Hansen E, Brockstedt-Rasmussen H et al.
Hydroxyapatite coating enhances fixation of porous coated implants. A comparison in
dogs between press fit and noninterference fit.
Acta Orthop Scand.
1990;
61
299-306
- 18
Søballe K, Hansen E, Brockstedt-Rasmussen H et al.
Hydroxyapatite coating converts fibrous tissue to bone around loaded implants.
J Bone Joint Surg [Br].
1993;
75
270-278
- 19
Moroni A, Caja V, Egger E L et al.
Histomorphometry of hydroxyapatite coated and uncoated porous titanium bone implants.
Biomaterials.
1994;
15
926-930
- 20
Coathup M J, Blunn G, Flynn N et al.
A comparison of bone remodelling around hydroxyapatite-coated, porous-coated and grit-blasted
hip replacements retrieved at post-mortem.
J Bone Joint Surg [Br].
2001;
83
118-123
- 21
Bauer T W, Geesink R, Zimmerman R et al.
Hydroxyapatite-coated femoral stems. Histological analysis of components retrieved
at autopsy.
J Bone Joint Surg [Am].
1991;
73
1439-1452
- 22
Søballe K, Gotfredsen K, Brockstedt-Rasmussen H et al.
Histologic analysis of a retrieved hydroxyapatite-coated femoral prosthesis.
Clin Orthop Relat Res.
1991;
272
255-258
- 23
Hardy D C, Frayssinet P, Guilhem A et al.
Bonding of hydroxyapatite-coated femoral prostheses. Histopathology of specimens from
four cases.
J Bone Joint Surg [Br].
1991;
73
732-740
- 24
D'Antonio J A, Capello W, Crothers O D et al.
Early clinical experience with hydroxyapatite-coated femoral implants.
J Bone Joint Surg [Am].
1992;
74
995-1008
- 25
Abrahams T G, Crothers O.
Radiographic analysis of an investigational hydroxyapatite-coated total hip replacement.
Invest Radiol.
1992;
27
779-784
- 26
Vedantam R, Ruddlesdin C.
The fully hydroxyapatite-coated total hip implant. Clinical and roentgenographic results.
J Arthroplasty.
1996;
11
534-542
- 27
Osborn J.
The biological behavior of the hydroxyapatite ceramic coating on a titanium stem of
a hip prosthesis – the first histological evaluating of human autopsy material.
Biomed Technik.
1987;
32
177-183
- 28
Lintner F, Böhm G, Huber M et al.
Histology of tissue adjacent to an HAC-coated femoral prosthesis. A case report.
J Bone Joint Surg [Br].
1994;
76
824-830
- 29
Rahbek O, Overgaard S, Lind M et al.
Sealing effect of hydroxyapatite coating on peri-implant migration of particles. An
experimental study in dogs.
J Bone Joint Surg [Br].
2001;
83
441-447
Univ. Prof. Dr. Karl A. Zweymüller
Orthopädie
Orthopädisches Krankenhaus Gersthof
Wielemansgasse 28
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Österreich
Phone: +43/1/3 67 40 33
Fax: +43/1/3 67 40 33-4
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