CSTiTM Clinical Experience
Over 15 years of clinical success
Our implant designs are well matched with the CSTi porous coating technology. These recent articles demonstrate the clinical success of CSTi with several of our product lines, including: the Natural-Knee® system, Natural-HipTM and APR® hip stems, and hemispherical acetabular components.
CSTi for Hip Implants
Udomkiat P, Dorr LD, Wan Z. Cementless hemispheric
porous-coated sockets implanted with press-fit technique without screws:
average ten-year follow-up. J Bone Joint Surg Am. 2002
Jul;84-A(7):1195-1200. Reprint available: Part #1001-45-042
Link to abstract via Medline
This study followed 103 patients (110
hips) with APR acetabular cups an average of 10.2 years. All of the cups
were implanted without screw fixation, employing an under-ream of 1-3 mm
for initial stability and ingrowth into the CSTi coating for long-term
stability. The 12-year rate of survival of the acetabular cup was 99.1%.
On self-assessment questionnaires, 88% of patients rated their outcome as
excellent or very good, 10% as good, and 2% as fair. The researchers
state, “We have confidence in this method of fixation because of the low
prevalence of radiolucent lines, particularly progressive radiolucent
lines.” (Note: The APR cup was a predecessor of the current Converge
CSTi Porous Acetabular Cup, which is also a hemispherical cup with CSTi
porous coating.)
Hofmann AA, Feign ME, Klauser W, VanGorp CC, Camargo MP.
Cementless primary total hip arthroplasty with a tapered, proximally
porous-coated titanium prosthesis. J Arthroplasty. 2000
Oct;15(7):833-9. Reprint available: Part #1001-22-041
Link to abstract via Medline
87 consecutive patients (100 hips) received the Natural-Hip stem with
proximal CSTi porous coating. Six patients were lost to follow-up, and
four died during the follow-up period of reasons unrelated to surgery.
The average Harris Hip Score at latest follow-up was 94. The researchers
observed no femoral subsidence. There was no femoral component loosening
and thus no revision for femoral loosening.
Hofmann AA, Bloebaum RD, Bachus KN. Progression of human
bone ingrowth into porous-coated implants. Acta Orthop Scand.
1997 Apr;68(2):161-6.
Link to abstract via Medline
This study found that ingrowth of human
cancellous bone into porous coating plateaus at about 9 months
postoperatively.
Bloebaum RD, Mihalopoulus NL, Jensen JW, Dorr LD.
Postmortem analysis of bone growth into porous-coated acetabular
components. J Bone Joint Surg Am. 1997 Jul;79(7):1013-22.
Link to abstract via Medline
Seven CSTi-coated hemispherical shells
were retrieved postmortem for analysis. These had an average ABI of 84%
and ingrowth of 12%.
Pidhorz LE, Urban RM, Jacobs JJ, Sumner DR, Galante JO. A
quantitative study of bone and soft tissues in cementless porous-coated
acetabular components retrieved at autopsy. J Arthroplasty.
1993 Apr;8(2):213-25.
Link to abstract via Medline
Postmortem analysis was performed on 11 titanium fiber-mesh coated acetabular shells, which had been in place an average of 41 months. The researchers found ABI’s in the range of 0-55% and an ingrowth average of 12%.
Cook SD, Barrack RL, Thomas KA, Haddad RJ. Quantitative
analysis of tissue growth into human porous total hip components. J
Arthroplasty. 1988;3(3):249-62.
Link to abstract via Medline
Analysis was performed on 14 Co-Cr bead coated acetabular inserts. The researchers found ingrowth in the range of 0-16%.
CSTi for Knee Implants
Hofmann AA, Evanich CJ, Ferguson RP, Camargo MP. Ten- to
14-year clinical followup of the cementless Natural-Knee system. Clin
Orthop. 2001 Jul;388:85-94. Reprint available: Part #1001-01-045
Link to abstract via Medline
This study followed 141 patients (176
knees) with the Natural-Knee CSTi porous-coated total knee system an
average of 12 years. The researchers found a long-term survivorship of
95.1% when focusing on bony attachment; this does not include the three
revisions associated with infection or the five revisions due to late
posterior cruciate ligament failure. At ten years, the femoral and tibial
components demonstrated survivorship of 99.1% and 99.6, respectively. The
metal-backed patellar component had a survivorship of 95.1%. At last
follow-up, the HSS knee scores were 97.8±4.7 points.
Evanich CJ, Tkach TK, Von Glinski S, Camargo MP, Hofmann AA.
6- to 10-year experience using countersunk metal-backed patellas. J
Arthroplasty. 1997 Feb;12(2):149-54. Reprint available: Part
#1000-02-076
Link to abstract via Medline
Of 302 consecutive knee arthroplasties employing the CSTi-coated metal-backed Natural-Knee patella, 212 were available for 6-10 follow-up evaluation. (Fifty-nine patients had died, and 31 were lost to follow-up.) At last follow-up, the mean HSS knee score was 98 points. Overall patellar survivorship was found to be 96%.
Baldwin JL, El-Saied MR, Rubinstein RA. Uncemented total
knee arthroplasty: Report of 109 titanium knees with cancellous-structured
porous coating. Orthopedics. 1996 Feb;19(2):123-30.
Link to abstract via Medline
This study followed 109 Natural-Knee arthroplasties 3-5 years. 96% of patients had good or excellent results. 82% demonstrated no radiolucencies. The researchers found no complete radiolucencies under any implant, and none of the knees were revised for loosening.
Hofmann AA, Murdock LE, Wyatt RW, Alpert JP. Total knee
arthroplasty two- to four-year experience using an asymmetric tibial tray
and a deep troclear-grooved femoral component. Clin Orthop. 1991
Aug;(269):78-88.
Link to abstract via Medline
This study followed 183 Natural-Knee
arthroplasties 2-4 years. 96% of patients had good or excellent results.
There was no revision for component loosening. Six components were
obtained for analysis at the time of revision, and three were obtained
postmortem. These demonstrated bone ingrowth into the CSTi porous coating
of up to 40% at 27 months.
Bloebaum RD, Bachus KN, Jensen JW, Scott DF, Hofmann AA.
Porous-coated Metal-backed Patellar Components in Total Knee Replacement.
A Postmortem Retrieval Analysis, J Bone Joint Surg Am.
80(4):518-28, 1998.
Link to abstract via Medline
In this study of CSTi-coated
metal-back patellas, an average ABI of 86% and ingrowth of 13% were found.
Bloebaum RD, Bachus KN, Jensen JW, Hofmann AA.
Postmortem analysis of consecutively retrieved asymmetric porous-coated
tibial components. J Arthroplasty. 1997 Dec;12(8):920-9.
Link to abstract via Medline
Postmortem analysis was preformed on
eight consecutively retrieved Natural-Knee tibial components with CSTi
porous coating. The ABI averaged 73%, with no radiolucencies in the
series.
Bloebaum RD, Rhodes DM, Rubman MH, Hofmann AA. Bilateral
tibial components of different cementless designs and materials.
Clin Orthop. 268:179-87, 1991.
Link to abstract via Medline
In this study, two cementless tibial
components (one Natural-Knee CSTi-coated component and one cobalt-chrome
beaded component) underwent postmortem analysis. The CSTi implant had
been in place for 19 months and the CoCr-beaded for 25 months. The ABI
for the CSTi and CoCr-beaded implants were 67% and 9% respectively. The
CoCr-beading implant showed no bone within the pores, while the CSTi was
22% ingrown.
Sumner DR, Kienapfel H, Jacobs JJ, Urban RM, Turner TM, Galante JO.
Bone ingrowth and wear debris in well-fixed cementless porous-coated tibial
components removed from patients. J Arthroplasty.
10(2):157-67, 1995.
Link to abstract via Medline
Postmortem analysis was performed on
13 titanium fiber-mesh tibial components at an average length of
implantation of 15.3 months. The ABI averaged 27% and the ingrowth, 9.5%.
Vigorita VJ, Minkowitz B, Dichiara JF, Higham PA. A
histomorphometric and histologic analysis of the implant interface in five
successful, autopsy-retrieved, noncemented porous-coated knee
arthroplasties. Clin Orthop. 1993 Aug;(293):211-8.
Link to abstract via Medline
Analysis was performed on five
retrieved CoCr-beaded tibial baseplates. The ABI was 36%, and the
ingrowth averaged 6%.
