n Feature Article
Excellent Results of Primary THA Using a
Highly Porous Titanium Cup
Qais Naziri, MD; Kimona Issa, MD; Robert Pivec, MD; Steven F. Harwin, MD;
Ronald E. Delanois, MD; Michael A. Mont, MD
abstract
Full article available online at Healio.com/Orthopedics. Search: 20130327-10
Cementless acetabular cups for primary total hip arthroplasty have had excellent results, with failure rates typically less than 5% at up to 10-year follow-up. Tritanium is
a 3-dimensional metal interface that has been used for porous biological fixation. The
purpose of this study was to review the clinical and radiographic results of the use
of Tritanium cups (Stryker Orthopaedics, Mahwah, New Jersey) for primary total hip
arthroplasty. Two hundred eighty-eight total hip arthroplasties performed using a porous titanium acetabular cup in 252 patients between 2008 and 2010 were reviewed.
One hundred thirty-three men and 119 women with a mean age of 58 years (range,
18-88 years) were included. Mean follow-up was 36 months (range, 24-56 months).
Outcomes evaluated were implant survivorship, Harris Hip Score, complications, and
radiographic outcomes. At final follow-up, no cup failures had occurred. Mean Harris
Hip Score improved from 53 points (range, 33-82 points) preoperatively to 91 points
(range, 64-100 points) postoperatively. One complication occurred; a 64-year-old
woman with recurrent postoperative effusions underwent hip exploration and required
abductor mechanism repair. On radiologic evaluation, no signs existed of progressive
radiolucencies or changes in cup position. The survivorship of the Tritanium cup and
the low complication rate is comparable with previous studies using other porousmetal prostheses. Longer follow-up study is needed and assessment of the results of
using this implant in the revision setting is important.
Figure: Hemispherical multi-hole shell design
(Stryker Orthopaedics, Mahwah, New Jersey).
The authors are from the Center for Joint Preservation and Reconstruction (QN, KI, RP, RED, MAM),
Rubin Institute for Advanced Orthopedics, Sinai Hospital, Baltimore, Maryland; and the Adult Reconstruction
and Total Joint Replacement Service (SFH), Beth Israel Medical Center, New York, New York.
Drs Naziri, Issa, and Pivec have no relevant financial relationships to disclose. Dr Harwin receives
royalties from Stryker and SLACK, Inc; is on the speakers bureaus of Stryker and Convatec; is a paid
consultant for Stryker and Convatec; and has stock or stock options in Stryker. Dr Delanois is on the
speakers bureaus of Omni and Stryker; is a paid consultant for Stryker; and is a board member of the
Maryland Orthopedic Association. Dr Mont receives royalties from Stryker; is a consultant for Janssen,
Sage Products, Inc, Salient Surgical, Stryker, OCSI, and TissueGene; receives institutional support from
Stryker; and is on the speakers bureau of Sage Products, Inc.
Funding was received from Stryker Orthopaedics in support of this work.
Correspondence should be addressed to: Michael A. Mont, MD, Center for Joint Preservation
and Replacement, Rubin Institute for Advanced Orthopedics, Sinai Hospital, 2401 W Belvedere Ave,
Baltimore, MD 21215 ([email protected]).
doi: 10.3928/01477447-20130327-10
e390
ORTHOPEDICS | Healio.com/Orthopedics
THA Using a Titaniium Cup | Naziri et al
O
ver the past 2 decades, cementless
acetabular cups for primary total
hip arthroplasty (THA) have had
excellent results, with failure rates typically
less than 5% and with many designs showing
less than 1% failure at up to 10-year followup.1-8 Three senior authors (S.F.H., R.E.D.,
M.A.M.) noted an approximate 1% failure
rate at less than 5-year follow-up using various hydroxyapatite, sintered, porous foamcoated acetabular prostheses. Although the
failure rate is low, newer interface materials
must be sought for cementless acetabular
fixation to further reduce cases of loosening
and to ensure long-term durability. In addition, similar outcomes have to be evaluated
in revision settings.9-11
Highly porous titanium is a 3dimensional metal interface that has been
used for porous biological fixation. It is
similar in structure to porous tantalum
acetabular cups.3,5,12-14 The Tritanium
acetabular cup (Stryker Orthopaedics,
Mahwah, New Jersey) is expected to have
similar excellent results when compared
with other porous metal components. The
3 senior authors began using these cups in
2008 for all primary THAs.
The authors reviewed the clinical and
radiographic results of the use of titanium
cups for primary THA. In specific, outcomes evaluated included failure rates,
Harris Hip Scores, complication rates, and
radiographic findings.
Materials and Methods
The authors evaluated 288 THAs performed in 252 patients by 3 experienced
adult reconstructive surgeons (S.F.H.,
R.E.D., M.A.M.) at 2 high-volume institutions using a porous titanium acetabular
cup between 2008 and 2010. One hundred
thirty-three men and 119 women with a
mean age of 58 years (range, 18-88 years)
were included. Mean follow-up was 36
months (range, 24-56 months). Indications for THA were primary osteoarthritis
(n5250), osteonecrosis (n527), rheumatoid arthritis (n57), and femoral neck fracture (n54). Institutional review board approval was obtained from both institutions.
The Tritanium primary acetabular cup
has a hemispherical shell with a repeating lattice design, 72% porosity, a coefficient of friction of 1.01, and an average
pore size of 546 microns (Figure 1).15 The
component is available in a solid back
shell (a solid design) and hemispherical
cluster hole shell (with clustered screw
holes). The solid and the cluster hole designs range in size from 44 to 66 mm. The
Tritanium multi-hole shell has multiple
screw holes and is available in sizes 48 to
80 mm. The multi-hole shell is produced
by a different manufacturing process, but
the pore structure and size are similar. In
the current study, 218, 57, and 13 hips
received solid back shells, hemispherical
shells, and cluster hole shells, respectively, and the sizes of the acetabular components used ranged from 48 to 64 mm.
Clinical evaluation was based on Harris
Hip Score results.16 All patients returned
for follow-up at approximately 6 weeks,
6 and 12 months, and yearly thereafter.
At initial follow-up, patients were exam-
1A
ined and assessed for surgical complications, such as prolonged wound drainage,
hematoma formation, superficial or deep
infection, deep venous thrombosis, dislocation, intractable pain, nerve palsy, and
cup failure.
Standard anteroposterior and frogleg lateral radiographs were obtained at
each follow-up for all patients and were
reviewed by the senior authors. The acetabular zones described by DeLee and
Charnley17 were used to assess bone fixation using the Anderson Orthopaedic Research Institute radiographic Criteria.18
Aseptic loosening was defined as 2 mm or
more of progressive radiolucencies on serial radiographs.
Collected data were entered into an
Excel spreadsheet (Microsoft Corp, Redmond, Washington) and were analyzed using GraphPad Prism (GraphPad Software,
San Diego, California). Failure was defined
as removal or exchange of the acetabular
component due to an aseptic cause.
Results
At final follow-up, aseptic acetabular
component survivorship was 100%, and
no titanium cup failure had occurred.
Mean Harris Hip Score improved from
53 points (range, 33-82 points) preoperatively to 91 points (range, 64-100 points)
postoperatively, a mean improvement of
37 points (range, 20-58 points).
One major complication occurred,
making the complication rate approximately 0.4%. A 64-year-old woman had
recurrent postoperative effusions and un-
1B
1C
Figure 1: Tritanium acetabular cup (Stryker Orthopaedics, Mahwah, New Jersey). Solid back shell design (A) . Hemispherical cluster-hole shell design (Stryker
Orthopaedics) (B). Hemispherical multi-hole shell design (Stryker Orthopaedics) (C).
APRIL 2013 | Volume 36 • Number 4
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n Feature Article
THA Using a Titanium Cup | Naziri et al
derwent hip exploration with abductor
mechanism repair 3 months postoperatively. At last follow-up 25 months postoperatively, her Harris Hip Score was 90
points.
On radiographic analysis, no components showed changes in alignment or
inclination angles. Zonal radiographic
analysis revealed no signs of progressive
radiolucencies or cup migration (Figure 2).
Discussion
The use of porous metals in cementless
THA has had successful results at mid- to
long-term follow-up in multiple studies.
In the current study, the authors assessed
the short-term survivorship of a new highly porous titanium metal acetabular component in primary THA for the treatment
of various hip arthritis etiologies. The
clinical outcomes (ie, Harris Hip Score
and complication rate) were assessed and
compared with previously reported data
on other highly porous metal prostheses.
The current excellent results are comparable with those reported for other
2A
2B
2C
Figure 2: Postoperative anteroposterior hip radiograph of a patient who received a Tritanium cup (Stryker
Orthopaedics, Mahwah, New Jersey) (A). Anteroposterior hip radiograph at 1-year follow-up (B). Anteroposterior hip radiograph at 3-year follow-up (C).
highly porous metal acetabular components.1-3,5,19,20 Gruen et al3 reported the
outcomes of 414 porous tantalum cups
(Trabecular Metal; Zimmer, Inc, Warsaw,
Indiana) with a pore size of approximately
550 microns that had a 100% survivor-
ship rate at 2-year follow-up. Macheras
et al5 reported survivorships of up to 99%
at 8- to 10-year follow-up in 151 hips that
had received a porous tantalum Trabecular
Metal monoblock acetabular component
(Zimmer, Inc) with an approximate mean
Table
Outcomes of Porous Metal Cups in Primary Total Hip Arthroplasty
Mean HHS (Range), Points
No. of
Patients (Hips)
Approx FU
(range), y
Highly
Porous
Metal Type
Preoperative
Postoperative
Survivorship (%)
Notes
Gruen et al3
(414)
3 (2-5)
Tantulum
49 (2-88)
90 (38-100)
100
HHS representative
of 82% of patients
Komarasamy
et al4
104 (112)
3 (1.5-4)
Tantulum
45 (NR)a
14 (12-60)a
100
99% of patients
were very satisfied
or satisfied with
procedure
Macheras et al5
138 (151)
9 (8-10)
Tantulum
44 (4-87)
97 (59-100)
99 at 8 y for aseptic
loosening or
mechanical failure
4.5% complication
rate
Malizos et al6
Author
218 (240)
5 (3-9.5)
Tantulum
48 (24-58)
94 (69-97)
98.75
Kostakos et al21
44 (51)
2y
Tantulum
41
91
100
Moen et al7
51 (51)
10.3
(9.6-10.8)
Tantulum
NR
NR
100
Current study
288 (252)
3 (2-5)
Titanium
53 (33-82)
91 (64-100)
100
Radiographic
analysis
Abbreviations: Approx FU, approximate follow-up; HHS, Harris Hip Score; NR, not reported.
a
Oxford Hip Score.
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ORTHOPEDICS | Healio.com/Orthopedics
THA Using a Titaniium Cup | Naziri et al
pore size of 550 microns. The Table shows
studies using porous metal acetabular cups.
Previous studies have reported similar
outcomes using porous-coated titanium acetabular components. Chen et al1 reported
a study of 145 THAs using a hemispheric
titanium fully porous coated Duraloc 100
and 1200 acetabular cups (DePuy, Warsaw, Indiana) with a mean pore size of 250
microns. They reported an overall KaplanMeier survivorship of 97.2% and no acetabular cup failure at 8-year follow-up and
a 4.1% dislocation rate at a minimum of 3
years postoperatively.1 No dislocations occurred in the current study. Grobler et al2
reported outcomes of 100 consecutive patients undergoing THA who had received
a porous-coated titanium cup (Duraloc 300
cup; DePuy) with a mean pore size of 250
microns. They reported a 10-year survivorship for cup loosening of 100%; however,
4 patients underwent liner revision (1 due
to dislocation and 3 due to periacetabular
osteolysis).2
The results of the highly porous titanium metal acetabular cup used in the
current study differ from the results of
some of the previously reported studies on older-generation titanium shells.
Cheung et al19 reported the outcomes of
66 THAs using a smooth hydroxyapatitecoated press-fit acetabular cup (Omnifit
PSL HA; Osteonics, Allendale, New
Jersey) with a pore size of approximately
250 microns. They reported cup survivorships of 95.4% and 83% at 5- and
9-year follow-up, respectively.19 Jafari et
al13 evaluated the outcomes of revision
THA in 207 patients (214 hips) receiving
hydroxyapatite-coated titanium acetabular cups (Stryker Orthopaedics) compared with 79 patients (81 hips) who had
received porous tantalum acetabular cups
(TM; Zimmer) and mean pore size of 550
microns. The failure rate (both mechanical or radiographic) was 8% at a mean
follow-up of approximately 52 months
(range, 24-98 months) for the titanium
cups and 6% at approximately 35 months
(range, 24-63 months) for the tantalum
APRIL 2013 | Volume 36 • Number 4
cups, respectively. Because 80% of the
failures in the titanium group occurred
after 6 months postoperatively, Jafari et
al13 reported that the older hydroxyapatite-coated titanium acetabular cups only
had the potential for bone ongrowth,
unlike the porous tantalum cup that had
successful bone ingrowth. Due to a pore
size and porosity that is comparable with
the porous tantalum cup, the titanium
shell used in the current study should allow for similar osseointegration.
Several limitations existed in the current study. It was not a prospective study,
and no comparison or matching groups
were used. All procedures were performed
by 3 high-volume, fellowship-trained
adult reconstructive surgeons; therefore,
the current results may not be easily reproducible by less-experienced or lowvolume surgeons. However, the results are
valuable because few reports have been
published on the outcomes of the Tritanium acetabular cups. More long-term
follow-up studies are needed to evaluate
the outcomes.
Conclusion
The excellent short-term clinical and
radiographic survivorship results for the
use of a porous titanium acetabular cup
are encouraging. The Tritanium acetabular cup may be an improvement over
other porous-coated titanium implants,
and the authors expect results comparable with those of other successful prostheses. Although further follow-up is
recommended, the authors will continue
to use this acetabular cup for primary
cases and will study its use in the revision setting.
3. Gruen TA, Poggie RA, Lewallen DG, et al.
Radiographic evaluation of a monoblock acetabular component: a multicenter study with
2- to 5-year results. J Arthroplasty. 2005;
20(3):369-378.
4. Komarasamy B, Vadivelu R, Bruce A, Kershaw
C, Davison J. Clinical and radiological outcome
following total hip arthroplasty with an uncemented trabecular metal monoblock acetabular
cup. Acta Orthop Belg. 2006; 72(3):320-325.
5. Macheras G, Kateros K, Kostakos A, Koutsostathis S, Danomaras D, Papagelopoulos
PJ. Eight- to ten-year clinical and radiographic outcome of a porous tantalum monoblock acetabular component. J Arthroplasty.
2009; 24(5):705-709.
6. Malizos KN, Bargiotas K, Papatheodorou
L, Hantes M, Karachalios T. Survivorship of
monoblock trabecular metal cups in primary
THA: midterm results. Clin Orthop Relat
Res. 2008; 466(1):159-166.
7. Moen TC, Ghate R, Salaz N, Ghodasra J, Stulberg SD. A monoblock porous tantalum acetabular cup has no osteolysis on CT at 10 years.
Clin Orthop Relat Res. 2011; 469(2):382-386.
8. Ramappa M, Bajwa A, Kulkarni A, McMurtry I, Port A. Early results of a new highly
porous modular acetabular cup in revision
arthroplasty. Hip Int. 2009; 19(3):239-244.
9. Blumenfeld TJ. Implant choices, technique,
and results in revision acetabular surgery: a
review. Hip Int. 2012; 22(3):235-247.
10. Kremers HM, Howard JL, Loechler Y, et al.
Comparative long-term survivorship of uncemented acetabular components in revision
total hip arthroplasty. J Bone Joint Surg Am.
2012; 94(12):e82.
11. Taylor ED, Browne JA. Reconstruction options for acetabular revision. World J Orthop.
2012; 3(7):95-100.
12. Bobyn JD, Stackpool GJ, Hacking SA, Tanzer M, Krygier JJ. Characteristics of bone
ingrowth and interface mechanics of a new
porous tantalum biomaterial. J Bone Joint
Surg Br. 1999; 81(5):907-914.
13. Jafari SM, Bender B, Coyle C, Parvizi J,
Sharkey PF, Hozack WJ. Do tantalum and
titanium cups show similar results in revision hip arthroplasty? Clin Orthop Relat Res.
2010; 468(2):459-465.
References
14. Unger AS, Lewis RJ, Gruen T. Evaluation
of a porous tantalum uncemented acetabular
cup in revision total hip arthroplasty: clinical
and radiological results of 60 hips. J Arthroplasty. 2005; 20(8):1002-1009.
1. Chen CJ, Xenos JS, McAuley JP, Young A,
Engh CA Sr. Second-generation porouscoated cementless total hip arthroplasties
have high survival. Clin Orthop Relat Res.
2006; (451):121-127.
15. Lohana P, Woodnutt DJ, Boyce DE. Sciatic
nerve palsy: a complication of posterior approach using enhanced soft tissue repair for
total hip arthroplasty. J Plast Reconstr Aesthet Surg. 2010; 63(4):e400-e401.
2. Grobler GP, Learmonth ID, Bernstein BP,
Dower BJ. Ten-year results of a press-fit,
porous-coated acetabular component. J Bone
Joint Surg Br. 2005; 87(6):786-789.
16. Harris WH. Traumatic arthritis of the hip
after dislocation and acetabular fractures:
treatment by mold arthroplasty. An end-result
e393
n Feature Article
study using a new method of result evaluation.
J Bone Joint Surg Am. 1969; 51(4):737-755.
tion in porous-coated acetabular components.
Clin Orthop Relat Res. 2006; (444):176-183.
17.DeLee JG, Charnley J. Radiological de
marcation of cemented sockets in total hip
replacement. Clin Orthop Relat Res. 1976;
(121):20-32.
19. Cheung KW, Yung SH, Wong KC, Chiu KH.
Early failure of smooth hydroxyapatite-coated press-fit acetabular cup--7 years of followup. J Arthroplasty. 2005; 20(5):627-631.
18. Moore MS, McAuley JP, Young AM, Engh
CA Sr. Radiographic signs of osseointegra-
20. Garcia-Rey E, Garcia-Cimbrelo E. Clinical
and radiographic results and wear perfor-
e394
mance in different generations of a cementless porous-coated acetabular cup. Int Orthop. 2008; 32(2):181-187.
21. Kostakos AT, Macheras GA, Frangakis CE,
Stafilas KS, Baltas D, Xenakis TA. Migration of the trabecular metal monoblock acetabular cup system. J Arthroplasty. 2010;
25(1):35-40.
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