- Email: [email protected]
Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty With a Mean Follow-Up of 18 Years
Accepted Manuscript Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty with a mean follow-up of 18 years George A. Macheras, Panagiotis Lepetsos, Andreas O. Leonidou, Panagiotis P. Anastasopoulos, Spyridon P. Galanakos, Lazaros A. Poultsides PII:
S0883-5403(17)30578-8
DOI:
10.1016/j.arth.2017.06.049
Reference:
YARTH 55975
To appear in:
The Journal of Arthroplasty
Received Date: 8 April 2017 Revised Date:
12 June 2017
Accepted Date: 28 June 2017
Please cite this article as: Macheras GA, Lepetsos P, Leonidou AO, Anastasopoulos PP, Galanakos SP, Poultsides LA, Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty with a mean follow-up of 18 years, The Journal of Arthroplasty (2017), doi: 10.1016/ j.arth.2017.06.049. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT 1. Article title: Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty with a mean follow-up of 18 years.
George A. Macheras (1), email: [email protected] Panagiotis Lepetsos (1), email: [email protected] Andreas O. Leonidou (1), email: [email protected]
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2. Authors’ Names and institutional affiliations
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Panagiotis P. Anastasopoulos (1), email: [email protected] Spyridon P. Galanakos (1), email: [email protected]
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Lazaros A. Poultsides (2), email: [email protected]
1. 4th Department of Trauma & Orthopaedics, KAT Hospital, Nikis 2, 14561, Kifissia, Athens, Greece
2. Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic
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Surgery, Hospital for Special Surgery, New York, New York.
3. Work attributed to:
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4th Department of Trauma & Orthopaedics, KAT Hospital, Nikis 2, 14561, Kifissia,
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Athens, Greece
4. Corresponding Author: Name: George A. Macheras, MD, PhD Mailing address: 4th Department of Trauma & Orthopaedics, KAT Hospital, Nikis 2, 14561, Kifissia, Athens, Greece Telephone Numbers: + 306932265233 + 302132086319 E-mail: [email protected] (email address can be published)
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ACCEPTED MANUSCRIPT 5. Request for reprints should be addressed to the corresponding author
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Original Article / Clinical Follow-up report
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ARTICLE TITLE: Survivorship of a Porous Tantalum Monoblock Acetabular
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Component in Primary Hip Arthroplasty with a mean follow-up of 18 years.
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ABSTRACT
5 Background
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The use of porous tantalum for the acetabular component in primary total hip
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arthroplasty (THA) has demonstrated excellent short-term and mid-term results.
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However, long term data are scarce. The purpose of this prospective study is to report
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the long-term clinical and radiological outcome following use of an uncemented
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porous tantalum acetabular component in primary THA with a minimum follow-up of
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17.5 years, in a previously studied cohort of patients.
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Methods
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We prospectively followed 128 consecutive primary THAs in 140 patients, between
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November 1997 and June 1999. A press-fit porous tantalum monoblock acetabular
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component was used in all cases. All patients were followed clinically and
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radiographically for a mean of 18.1 years (range 17.5 – 19 years).
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19 Results
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Mean age of patients at the time of operation was 60.4 years old. Harris hip score,
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Oxford Hip Score and range of motion (ROM) were dramatically improved in all
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cases (p < 0.001). At last follow-up, all cups were radiographically stable with no
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evidence of migration, gross polyethylene wear, progressive radiolucencies, osteolytic
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lesions or acetabular fractures. The survivorship with re-operation for any reason as
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end point was 92.8% and the survivorship for aseptic loosening as an end point was
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100%.
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Conclusions
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The porous tantalum monoblock cup in primary THA demonstrated excellent clinical
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and radiographic outcomes with no failures because of aseptic loosening at a mean
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follow-up of 18.1 years.
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Key Words: total hip arthroplasty; porous tantalum; monoblock acetabular cup;
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trabecular metal; long-term follow-up
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MANUSCRIPT
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Introduction
40 Total hip arthroplasty (THA) is one of the most successful operations
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worldwide and has proved to be a very effective procedure at improving pain and
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restoring function and quality of life in patients with hip osteoarthritis (OA) [1].
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Despite substantial improvements in cementless THA implants, with vast
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improvements in the contact surface to the bone, periprosthetic osteolysis causing
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aseptic loosening is the major factor of failure of acetabular fixation reducing the
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survival of total hip arthroplasty (THA) [2-3]. In an attempt to decrease the rate of
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osteolysis and enhance fixation, monoblock acetabular components have been
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utilized. The main advantage of this acetabular uncemented component is the
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elimination of extra-articular back surface polyethylene (PE) wear and metallic debris
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generated by locking screws. The absence of screw holes increases the surface area
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for ingrowth, and the elliptical configuration of the component allows better
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cooptation of the shell to the dome of the acetabulum [4-5]. Reported disadvantages
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include the inability to enhance fixation with screws, to change the orientation of an
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elevated liner rim and to assess cup seating [6].
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The contact surface to the bone is another important factor for the
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incorporation and the long term survival of the prosthesis. Porous tantalum is a highly
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osteoconductive biomaterial, initially introduced in orthopedics in 1997, in order to
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overcome problems related to implant loosening [7], with a subsequent rapid
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evolution of orthopedic applications [8]. Its porosity is 80% of the total volume and
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the mean porous diameter is 550 µm, which is optimal for bone ingrowth and on-
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growth [9]. Moreover, the material has a modulus of elasticity close to that of the
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cancellous bone, producing a more physiologic transfer of forces to the pelvis and
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decreasing the potential for acetabular stress shielding [10]. The use of porous
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tantalum for the acetabular component in THA has demonstrated excellent short-term
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and mid-term results in primary THA [11-12]. In a previous study, we have reported
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the mid-term clinical and radiological outcome of this uncemented acetabular
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component in primary THA with an 8- to 10- years follow-up [11]. The purpose of
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this prospective study is to report the updated results of the same cohort of patients
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with a minimum follow-up of 17.5 years.
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Materials and Methods
72 After approval of the hospital review board, we prospectively followed 156
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consecutive primary THAs in 143 patients, between November 1997 and June 1999.
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Eight patients died and 7 patients were lost to the final follow-up, leaving 128 patients
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(140 hips) for analysis. Primary OA was the most common underlying cause of THA.
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Demographic characteristics of the study cohort are shown in Table 1.
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A press-fit porous tantalum monoblock acetabular component (Trabecular
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Metal Monoblock Acetabular Component System; Zimmer Inc, Warsaw) was used in
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all cases. The component has 2 distinct profiles: solid trabecular metal (TMT) backing
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without peripheral screws and solid TMT backing with peripheral screw holes for
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adjunctive fixation. All the procedures were performed by the senior surgeon using a
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posterior surgical approach. The acetabulum was prepared with hemispherical
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reamers. The diameter of the final reamer matches the polar diameter of the acetabular
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component and is 2 mm less than the equatorial diameter. The acetabular component
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was inserted using press-fit technique, taking particular care to prevent soft tissue
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interposition between the implant and the acetabulum bone during implantation. The
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target cup position was 15o – 20o of anteversion and 40o – 45o of inclination. No bone
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grafting was used in any of these acetabular reconstructions. Intraoperatively, the
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initial stability of the acetabular prosthesis was accessed manually and was considered
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satisfactory in all cases. There were 5 cases of developmental dysplasia of the hip
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(DDH) in which peripheral screws were used to gain additional acetabular component
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stability: one with one screw and 4 where 2 screws were used. In all cases, the
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Continuum F-115 Hip Stem (Implex, Allendale, NJ) and ultra high molecular weight
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polyethylene (UHMWPE) with a 28 mm ceramic head was used. Immediate
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postoperative radiographs revealed well-fixed and positioned components as per the
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surgical guidelines for successful implantation. All patients received low-molecular-
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weight heparin 12 hours postoperatively and for 6 weeks thereafter. On the second
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postoperative day, the patients were mobilized with partial weight bearing for 6 weeks
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thereafter, followed by full weight bearing.
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All patients were evaluated clinically preoperatively and at 6, 12, and 24
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weeks and 12 months and then at 2, 5, 8, 10 and 19 years. Clinical measurement 4
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score (OHS) [13-14]. At same time intervals, all patients had radiologic evaluation
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using standard anteroposterior pelvic radiographs and the lateral of the operated hip.
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All patients were seen within 1 year of data collection. Radiographs were evaluated to
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assess cup inclination, initial polar gaps, radiolucent lines, osteolysis, cup migration,
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implant loosening, and gross PE wear. The radiographic cup inclination is defined as
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the angle between the longitudinal axis of the patient and a perpendicular to the major
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axis of the cup projection [15]. The presence of initial gaps in the polar region, as sign
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of incomplete seating of the monoblock cup, was assessed on the immediate
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postoperative radiographs. Regions in which the surface of the acetabular component
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was not in contact with bone on the immediate postoperative radiographs were
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classified as gaps, to distinguish them from radiolucent lines that appear on
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subsequent films in areas where no gaps had existed initially. Gap width, location, and
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changes over time were measured. Gap size was defined as the maximum width of
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each gap. If present, these were followed on future films to determine whether they
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had resolved (filled-in), persisted or expanded. The presence of new radiolucent lines
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at the bone–prosthesis interface was evaluated on all follow-up films using three
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contiguous acetabular zones delineated by DeLee and Charnley [16].
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Signs of cup migration and the appearance of osteolysis were evaluated on all
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follow-up films, in comparison to the immediate postoperative images. A component
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was considered to have migrated if change in position >3 mm or a change of the cup
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angle > 5o with respect to the immediate postoperative radiographs according to the
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criteria of Massin et al [17].Acetabular components were considered to be stable if
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they had no radiolucent lines or migration on the radiographs at the final follow-up.
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Gross PE wear was considered present when obvious concentric or eccentric femoral
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head penetration into the PE liner was observed on latest follow-up radiographs.
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Radiographic evaluation was performed by two orthopaedic surgeons, who were not
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involved in the surgery or the patient care.
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Descriptive statistics are presented as mean ± SD. Student’s unpaired t test
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was used to compare continuous values. Statistical analyses were performed using the
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PASW18.0 (SPSS release 18.0; SPSS Inc., Chicago, Illinois) with a level of
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significance set at p< 0.05.
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Results
137 The minimum follow-up time was 17.5 years, and the maximum follow-up
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time was 19 years, with a mean follow-up of 18,1 years. Of the 140 THAs, no
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acetabular component was revised or needed revision at the last follow-up because of
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aseptic loosening, mechanical failure or osteolysis. As shown in Table 2, HHS, OHS
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and ROM were dramatically improved in the latest follow-up.
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Ten patients required subsequent surgery. In one patient, the acetabular
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component was revised at 50 months for recurrent dislocation. Upon visual
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inspection, the revised acetabular component had extensive bone coverage. Two
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patients required two-stage exchange of both femoral stem and acetabular component
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because of deep infection, 6 and 7.5 years postoperatively. In the retrieved acetabular
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components, excellent bone coverage and penetration in the porous tantalum surface
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was noticed, and despite the infection, the acetabular component was stable at the
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time of removal. Aseptic loosening of the femoral stem occurred in 2 patients at 8 and
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13 years postoperatively, and required only revision of the femoral stem, as the
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acetabular component was stable and well-fixed. Three patients sustained a
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Vancouver B1 periprosthetic femoral fracture because of fall, and were treated with
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open reduction and internal fixation. One patient with superficial infection was treated
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with local debridement and antibiotics and one patient with wound hematoma was
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treated with wound drainage. One single case with early dislocation in one hip was
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treated by closed reduction without further incident. Deep vein thrombosis was seen
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in 2 hips and these were successfully treated conservatively. At the last follow-up, the
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survivorship with re-operation for any reason as end point was 92.8% and the
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survivorship for aseptic loosening as an end point was 100%.
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Acetabular component inclination in the initial postoperative radiograph was
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44,1° ± 4,3° (range 37.8° - 49.8°) and 44,4o ± 4,8o (range 37,2o – 50,6o) at the latest
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follow-up (p-value = 0.6). In the initial postoperative radiographs, periacetabular
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dome gaps were observed in 21 hips (15%).Thirteen of the gaps were measured less
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than 1 mm, and 8 of the gaps ranged from 1 to 3.5 mm. Six gaps were observed in
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zone 1, 12 gaps in zone 2 and 3 gaps in zone 3. Radiographic evidence of progressive
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gap filling was observed in all patients by 6 months. There was no further
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radiographic evidence of acetabular dome gaps at the latest follow-up. Moreover,
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there was no radiographic evidence of gross PE wear, backside wear, progressive
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radiolucencies, osteolytic lesions, acetabular fracture, or component subsidence
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(figures 1). At the latest follow-up, radiologic evaluation showed an increased bone
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density and remodeling and thickening of trabecular bone around the acetabular
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A B line at all 3 Charnley zones at 1 and 2 implant. One case had an acetabular radiolucent
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years but none at 5 years. This may be due to either patient positioning or gap filling.
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In the case with acetabular dome gaps, the acetabular component was deemed
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radiographically stable and the patient had no complaints of pain. No case of severe
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heterotopic ossification was observed.
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A Discussion
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Aseptic loosening of the acetabular component, induced by PE wear and
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periprosthetic osteolysis, is the most important limiting factor to the survival of
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uncemented THA [18-19]. In an effort to encounter the problem, acetabular
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components have evolved with the changes in design characteristics along with the
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surgical techniques. Monoblock cups are non-modular uncemented acetabular
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components in which the PE liner and shell are factory-preassembled into a single
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solid construct, diminishing the need for locking mechanisms and dome holes. The
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provided optimal liner-shell conformity, the elimination of liner-shell micromotion
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and the absence of screws and dome holes decrease the production of PE debris and
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prevent the debris access to the periacetabular regions of the pelvis, lowering the risk
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of periprosthetic osteolysis and the incidence of aseptic loosening [20]. The PE
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thickness is also an important factor as acetabular implants with thicker PE have less
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wear and better survival [21-22]. Porous tantalum possesses unique mechanical
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properties such as an interconnecting porous surface, which corresponds to 75% to
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80%, a mean pore diameter of 550 µm, a low modulus of elasticity and a high
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adherence, proliferation and differentiation and allowing for excellent primary
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stabilization of implants and broader use in orthopaedic surgery [7, 23]. The
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polyethylene liner is compression-molded into the metal shell to a depth of 1 - 2 mm,
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leaving 2 – 3 mm of porous tantalum for tissue ingrowth [24]. Merging the
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advantages of an elliptical monoblock design with the characteristics of porous
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tantalum, a porous tantalum monoblock cup has been used to improve longevity of
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cementless primary THA. Studies on tantalum monoblock cups using plain pelvic
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radiographs show a unique cancellous bone densification at the cup-bone interface,
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suggesting excellent ingrowth into the component [11, 24-26]. The lower rate of
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osteolysis observed with the use of UHMWPE, in comparison with the older
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generation PE, may be attributed to the fact that this monoblock construct allows for
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thicker PE even in small diameter cups and that the PE is press-molded in the TMT
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shell. In the present study, we focused on the long-term clinical and radiological
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results of porous tantalum monoblock acetabular component in primary hip surgery as
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we are among the first surgeons to use this implant worldwide.
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The excellent long-term results of this monoblock cup design may be
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compared to other long-term studies reporting on the performance of different
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monoblock cups with different ingrowth surfaces, metallic compositions, and
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elliptical or hemispherical shapes. No cup revision has been reported for 258 elliptical
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porous-coated titanium monoblock cups in 11 years of follow-up [27]. Excellent
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results have been reported for the non-modular porous-coated Morscher press-fit cup
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with 100% 10-year survival with no radiolucencies around the cup [28-29]. Another
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monoblock implant, the titanium-coated RM acetabular component, showed a 94%
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survival after 20 years of follow-up [30]. In a randomized controlled trial, porous
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tantalum monoblock cups demonstrated 100% survivorship, and significantly less
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radiolucency as compared to porous-coated titanium monoblock cups, at 12 years
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postoperatively [31]. However, a recent systematic review by Halma et al suggested
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that there is no significant difference in the rate of aseptic loosening, osteolysis or PE
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wear between monoblock and modular acetabular components [20]. The referred
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superiority of the monoblock cups may be attributed to the thicker PE and the
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elimination of micromotion and wear at the interface between the metallic shell and
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the PE liner.
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term results of the use of porous tantalum monoblock cups in THA [11-12, 24-26, 32-
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36]. In all studies, the survival of the porous tantalum acetabular component was
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100% and excellent clinical outcomes were reported. However, there is only one
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study in the literature, reporting the long-term outcomes for this cup design, with a
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mean follow-up of 15.6 years [37]. In our study, we observed 0% rate of aseptic
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loosening, migration or gross PE wear after a mean follow-up of 18.1 years (range
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17.5 – 19 years), coming in accordance with previously published studies. To the best
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of our knowledge, this is the longest follow-up reported for primary THAs performed
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with trabecular metal cups. Ten patients were re-operated for reasons irrelevant to the
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stability and fixation of the acetabular component. Clinical data, expressed by HHS,
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OHS and ROM, support the radiological conclusions.
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Radiographic review of our data has shown early series of periacetabular
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dome gaps in 23 hips (16%). However, at 6 months of follow-up, there was a gap
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filling, and no further radiographic evidence of periacetabular gaps was noted. The
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long-term results of our study support the hypothesis that the initial postoperative
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gaps at the bone–implant interface, do not influence long-term stability. We suggest
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that the osteoconductive properties of tantalum metal allows for the resolution of most
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line-to-line component to host bone differences found after primary THA.
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Komarasamy et al. also reported a high incidence (22%) of polar gaps in their series.
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All gaps were filled at the last follow-up [36]. Similarly, Gruen et al reported
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radiographic evidence of periacetabular gaps using the same acetabular component
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with complete gap filling at 2 years [35]. In studies, where some initial postoperative
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periacetabular dome gaps persisted for more than 2 years, the longevity of the implant
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was not compromised [26, 32]. The gaps seem to relate with the surgeon's ability to
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seat the acetabular component completely.
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The use of porous tantalum acetabular components in THA has several
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disadvantages. Implantation of the specific acetabular component might be
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demanding as dome contact cannot be visualized because of the lack of screw holes
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on the dome and the presence of the liner. When inserting the elliptical socket, it is
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necessary to seat the cup into the acetabular periphery so that it is circumferentially
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centered before impacting the cup medially. This seating prevents the rim of the cup
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impinging on the acetabular mouth and migrating superiorly when the cup is
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impacted. Furthermore, the high cost of the implant is the reason why we did not use
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this cup in elderly people. Finally, the lack of modularity does not allow isolated liner
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exchange. The specific implant is no longer available in the market. The present study has several limitations. First, this is a prospective
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observational case series without any control group with cups of a different design. A
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second limitation was related to the use of simple radiographs to evaluate osteolysis.
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Radiographs typically underestimate the true incidence and extent of periacetabular
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osteolysis, as computed tomographic (CT) scan is the modality of choice to detect
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such lesions. However, studies by Meneghini and Moen showed no evidence of
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osteolysis on CT scans of porous tantalum monoblock acetabular cups after a mean of
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7.7 years and 10.3 years, respectively [33, 38]. Nevertheless, overproduction of
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artifacts by porous tantalum may impair the ability of CT scan to assess osteolysis and
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bone ingrowth around the component [39]. Finally, only the gross PE wear was
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assessed while the linear and volumetric PE wear analysis with more sophisticated
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methods was not performed, possibly underestimating the presence of any subtle wear
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[40-42].
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In conclusion, the use of porous tantalum acetabular monoblock components
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in primary THA has shown excellent long-term clinical and radiographic outcome.
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The revision rate for aseptic loosening in the 17.5 to 19 years of follow-up was 0%.
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No radiolucencies, gross PE wear and acetabular cup migration were observed,
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findings that confirm the effectiveness of this implant and support the theoretical
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advantages of tantalum metal. Potential disadvantages of this trabecular metal
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monoblock cup do not seem to influence the survival of the surgery.
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Acknowledgements
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This research did not receive any specific grant from funding agencies in the public,
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commercial, or not-for-profit sectors.
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21. Zhu YH, Chiu KY, Tang WM. Review Article: Polyethylene wear and osteolysis in total hip arthroplasty. J Orthop Surg (Hong Kong). 2001; (9): 91-99. 22. Lee PC, Shih CH, Chen WJ, Tu YK, Tai CL. Early polyethylene wear and osteolysis in cementless total hip arthroplasty: the influence of femoral head size and polyethylene thickness. J Arthroplasty. 1999; (14): 976-981. 23. 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): 907-914. 24. Macheras GA, Papagelopoulos PJ, Kateros K, Kostakos AT, Baltas D, Karachalios TS. Radiological evaluation of the metal-bone interface of a porous tantalum monoblock acetabular component. J Bone Joint Surg Br. 2006; (88): 304309. 25. Mulier M, Rys B, Moke L. Hedrocel trabecular metal monoblock acetabular cups: mid-term results. Acta Orthop Belg. 2006; (72): 326-331. 26. 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): 159-166. 27. Poultsides LA, Sioros V, Anderson JA, Bruni D, Beksac B, Sculco TP. Ten- to 15-year clinical and radiographic results for a compression molded monoblock elliptical acetabular component. J Arthroplasty. 2012; (27): 1850-1856. 28. Garavaglia G, Lubbeke A, Barea C, Roussos C, Peter R, Hoffmeyer P. Tenyear results with the Morscher press-fit cup: an uncemented, non-modular, porouscoated cup inserted without screws. Int Orthop. 2011; (35): 957-963. 29. Gwynne-Jones DP, Garneti N, Wainwright C, Matheson JA, King R. The Morscher Press Fit acetabular component: a nine- to 13-year review. J Bone Joint Surg Br. 2009; (91): 859-864. 30. Ihle M, Mai S, Pfluger D, Siebert W. The results of the titanium-coated RM acetabular component at 20 years: a long-term follow-up of an uncemented primary total hip replacement. J Bone Joint Surg Br. 2008; (90): 1284-1290. 31. Wegrzyn J, Kaufman KR, Hanssen AD, Lewallen DG. Performance of Porous Tantalum vs. Titanium Cup in Total Hip Arthroplasty: Randomized Trial with Minimum 10-Year Follow-Up. J Arthroplasty. 2015; (30): 1008-1013. 32. Noiseux NO, Long WJ, Mabry TM, Hanssen AD, Lewallen DG. Uncemented porous tantalum acetabular components: early follow-up and failures in 613 primary total hip arthroplasties. J Arthroplasty. 2014; (29): 617-620. 33. 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): 382-386. 34. 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): 35-40. 35. Gruen TA, Poggie RA, Lewallen DG, Hanssen AD, Lewis RJ, O'Keefe TJ, et al. Radiographic evaluation of a monoblock acetabular component: a multicenter study with 2- to 5-year results. J Arthroplasty. 2005; (20): 369-378. 36. 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): 320-325. 37. De Martino I, De Santis V, Sculco PK, D'Apolito R, Poultsides LA, Gasparini G. Long-Term Clinical and Radiographic Outcomes of Porous Tantalum Monoblock
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Acetabular Component in Primary Hip Arthroplasty: A Minimum of 15-Year FollowUp. J Arthroplasty. 2016; (31): 110-114. 38. Meneghini RM, Ford KS, McCollough CH, Hanssen AD, Lewallen DG. Bone remodeling around porous metal cementless acetabular components. J Arthroplasty. 2010; (25): 741-747. 39. Levi AD, Choi WG, Keller PJ, Heiserman JE, Sonntag VK, Dickman CA. The radiographic and imaging characteristics of porous tantalum implants within the human cervical spine. Spine (Phila Pa 1976). 1998; (23): 1245-1250; discussion 1251. 40. Martell JM, Berdia S. Determination of polyethylene wear in total hip replacements with use of digital radiographs. J Bone Joint Surg Am. 1997; (79): 1635-1641. 41. McCalden RW, Naudie DD, Yuan X, Bourne RB. Radiographic methods for the assessment of polyethylene wear after total hip arthroplasty. J Bone Joint Surg Am. 2005; (87): 2323-2334. 42. Rahman L, Cobb J, Muirhead-Allwood S. Radiographic methods of wear analysis in total hip arthroplasty. J Am Acad Orthop Surg. 2012; (20): 735-743.
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Figure 1A-B. Postoperative (A) and 18-year follow-up (B) anteroposterior radiograph
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of the right hip after THA using the porous tantalum monoblock acetabular
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component. No evidence of gross PE wear, backside wear, radiolucencies, osteolytic
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lesions, acetabular fracture or component migration is observed.
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Figure 2A-F. Postoperative radiographs at (A) 2, (B) 6, (C) 12 weeks, (D) 6 months,
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(E) 3 years and (F) 18 years of a TMT cup. A periacetabular osteoarthritic cyst at
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zone 1 has been progressively filled 1 year after total hip arthroplasty.
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TABLE 1. Demographic characteristics of the study cohort.
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DDH: Developmental dysplasia of hip. AVN: Avascular necrosis. RA: Rheumatoid
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arthritis
No of patients
128
No of THAs
140
Male / Female
38 / 90
Mean age (years)
60,4 ± 12,6
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426 427 428
Reason for THA
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(range 24 – 72) Primary OA: 104
AVN: 9 RA: 2 429
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DDH: 25
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TABLE 2.HHS, OHS and ROM of the patients, pre-operatively, after 1 year of
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follow-up and at the latest follow-up.
433 1 year follow up
Latest follow-up
p-value
HHS
44.4 ± 13.4
95.4 ± 5.2
95.2 ± 6.9
< 0.0001
OHS
15.8 ± 6.3
43.1 ± 4.6
41.2 ± 2.5
< 0.0001
ROM (flexion)
72.5o ± 13.6o
102.5o ± 12.7o
100.5o ± 12.4o
< 0.0001
ROM (abduction)
15.7o ± 3.2o
40.9o ± 3.9o
40.1o ± 3.1o
< 0.0001
434
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B
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D
E
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S0883-5403(17)30578-8
DOI:
10.1016/j.arth.2017.06.049
Reference:
YARTH 55975
To appear in:
The Journal of Arthroplasty
Received Date: 8 April 2017 Revised Date:
12 June 2017
Accepted Date: 28 June 2017
Please cite this article as: Macheras GA, Lepetsos P, Leonidou AO, Anastasopoulos PP, Galanakos SP, Poultsides LA, Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty with a mean follow-up of 18 years, The Journal of Arthroplasty (2017), doi: 10.1016/ j.arth.2017.06.049. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT 1. Article title: Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty with a mean follow-up of 18 years.
George A. Macheras (1), email: [email protected] Panagiotis Lepetsos (1), email: [email protected] Andreas O. Leonidou (1), email: [email protected]
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2. Authors’ Names and institutional affiliations
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Panagiotis P. Anastasopoulos (1), email: [email protected] Spyridon P. Galanakos (1), email: [email protected]
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Lazaros A. Poultsides (2), email: [email protected]
1. 4th Department of Trauma & Orthopaedics, KAT Hospital, Nikis 2, 14561, Kifissia, Athens, Greece
2. Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic
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Surgery, Hospital for Special Surgery, New York, New York.
3. Work attributed to:
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4th Department of Trauma & Orthopaedics, KAT Hospital, Nikis 2, 14561, Kifissia,
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Athens, Greece
4. Corresponding Author: Name: George A. Macheras, MD, PhD Mailing address: 4th Department of Trauma & Orthopaedics, KAT Hospital, Nikis 2, 14561, Kifissia, Athens, Greece Telephone Numbers: + 306932265233 + 302132086319 E-mail: [email protected] (email address can be published)
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ACCEPTED MANUSCRIPT 5. Request for reprints should be addressed to the corresponding author
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Original Article / Clinical Follow-up report
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ARTICLE TITLE: Survivorship of a Porous Tantalum Monoblock Acetabular
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Component in Primary Hip Arthroplasty with a mean follow-up of 18 years.
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ABSTRACT
5 Background
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The use of porous tantalum for the acetabular component in primary total hip
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arthroplasty (THA) has demonstrated excellent short-term and mid-term results.
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However, long term data are scarce. The purpose of this prospective study is to report
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the long-term clinical and radiological outcome following use of an uncemented
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porous tantalum acetabular component in primary THA with a minimum follow-up of
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17.5 years, in a previously studied cohort of patients.
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Methods
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We prospectively followed 128 consecutive primary THAs in 140 patients, between
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November 1997 and June 1999. A press-fit porous tantalum monoblock acetabular
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component was used in all cases. All patients were followed clinically and
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radiographically for a mean of 18.1 years (range 17.5 – 19 years).
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19 Results
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Mean age of patients at the time of operation was 60.4 years old. Harris hip score,
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Oxford Hip Score and range of motion (ROM) were dramatically improved in all
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cases (p < 0.001). At last follow-up, all cups were radiographically stable with no
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evidence of migration, gross polyethylene wear, progressive radiolucencies, osteolytic
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lesions or acetabular fractures. The survivorship with re-operation for any reason as
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end point was 92.8% and the survivorship for aseptic loosening as an end point was
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100%.
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Conclusions
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The porous tantalum monoblock cup in primary THA demonstrated excellent clinical
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and radiographic outcomes with no failures because of aseptic loosening at a mean
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follow-up of 18.1 years.
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Key Words: total hip arthroplasty; porous tantalum; monoblock acetabular cup;
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trabecular metal; long-term follow-up
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MANUSCRIPT
38 39
Introduction
40 Total hip arthroplasty (THA) is one of the most successful operations
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worldwide and has proved to be a very effective procedure at improving pain and
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restoring function and quality of life in patients with hip osteoarthritis (OA) [1].
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Despite substantial improvements in cementless THA implants, with vast
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improvements in the contact surface to the bone, periprosthetic osteolysis causing
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aseptic loosening is the major factor of failure of acetabular fixation reducing the
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survival of total hip arthroplasty (THA) [2-3]. In an attempt to decrease the rate of
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osteolysis and enhance fixation, monoblock acetabular components have been
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utilized. The main advantage of this acetabular uncemented component is the
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elimination of extra-articular back surface polyethylene (PE) wear and metallic debris
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generated by locking screws. The absence of screw holes increases the surface area
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for ingrowth, and the elliptical configuration of the component allows better
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cooptation of the shell to the dome of the acetabulum [4-5]. Reported disadvantages
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include the inability to enhance fixation with screws, to change the orientation of an
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elevated liner rim and to assess cup seating [6].
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The contact surface to the bone is another important factor for the
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incorporation and the long term survival of the prosthesis. Porous tantalum is a highly
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osteoconductive biomaterial, initially introduced in orthopedics in 1997, in order to
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overcome problems related to implant loosening [7], with a subsequent rapid
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evolution of orthopedic applications [8]. Its porosity is 80% of the total volume and
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the mean porous diameter is 550 µm, which is optimal for bone ingrowth and on-
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growth [9]. Moreover, the material has a modulus of elasticity close to that of the
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cancellous bone, producing a more physiologic transfer of forces to the pelvis and
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decreasing the potential for acetabular stress shielding [10]. The use of porous
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tantalum for the acetabular component in THA has demonstrated excellent short-term
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and mid-term results in primary THA [11-12]. In a previous study, we have reported
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the mid-term clinical and radiological outcome of this uncemented acetabular
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component in primary THA with an 8- to 10- years follow-up [11]. The purpose of
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this prospective study is to report the updated results of the same cohort of patients
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with a minimum follow-up of 17.5 years.
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Materials and Methods
72 After approval of the hospital review board, we prospectively followed 156
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consecutive primary THAs in 143 patients, between November 1997 and June 1999.
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Eight patients died and 7 patients were lost to the final follow-up, leaving 128 patients
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(140 hips) for analysis. Primary OA was the most common underlying cause of THA.
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Demographic characteristics of the study cohort are shown in Table 1.
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A press-fit porous tantalum monoblock acetabular component (Trabecular
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Metal Monoblock Acetabular Component System; Zimmer Inc, Warsaw) was used in
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all cases. The component has 2 distinct profiles: solid trabecular metal (TMT) backing
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without peripheral screws and solid TMT backing with peripheral screw holes for
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adjunctive fixation. All the procedures were performed by the senior surgeon using a
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posterior surgical approach. The acetabulum was prepared with hemispherical
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reamers. The diameter of the final reamer matches the polar diameter of the acetabular
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component and is 2 mm less than the equatorial diameter. The acetabular component
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was inserted using press-fit technique, taking particular care to prevent soft tissue
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interposition between the implant and the acetabulum bone during implantation. The
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target cup position was 15o – 20o of anteversion and 40o – 45o of inclination. No bone
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grafting was used in any of these acetabular reconstructions. Intraoperatively, the
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initial stability of the acetabular prosthesis was accessed manually and was considered
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satisfactory in all cases. There were 5 cases of developmental dysplasia of the hip
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(DDH) in which peripheral screws were used to gain additional acetabular component
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stability: one with one screw and 4 where 2 screws were used. In all cases, the
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Continuum F-115 Hip Stem (Implex, Allendale, NJ) and ultra high molecular weight
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polyethylene (UHMWPE) with a 28 mm ceramic head was used. Immediate
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postoperative radiographs revealed well-fixed and positioned components as per the
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surgical guidelines for successful implantation. All patients received low-molecular-
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weight heparin 12 hours postoperatively and for 6 weeks thereafter. On the second
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postoperative day, the patients were mobilized with partial weight bearing for 6 weeks
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thereafter, followed by full weight bearing.
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All patients were evaluated clinically preoperatively and at 6, 12, and 24
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weeks and 12 months and then at 2, 5, 8, 10 and 19 years. Clinical measurement 4
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score (OHS) [13-14]. At same time intervals, all patients had radiologic evaluation
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using standard anteroposterior pelvic radiographs and the lateral of the operated hip.
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All patients were seen within 1 year of data collection. Radiographs were evaluated to
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assess cup inclination, initial polar gaps, radiolucent lines, osteolysis, cup migration,
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implant loosening, and gross PE wear. The radiographic cup inclination is defined as
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the angle between the longitudinal axis of the patient and a perpendicular to the major
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axis of the cup projection [15]. The presence of initial gaps in the polar region, as sign
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of incomplete seating of the monoblock cup, was assessed on the immediate
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postoperative radiographs. Regions in which the surface of the acetabular component
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was not in contact with bone on the immediate postoperative radiographs were
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classified as gaps, to distinguish them from radiolucent lines that appear on
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subsequent films in areas where no gaps had existed initially. Gap width, location, and
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changes over time were measured. Gap size was defined as the maximum width of
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each gap. If present, these were followed on future films to determine whether they
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had resolved (filled-in), persisted or expanded. The presence of new radiolucent lines
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at the bone–prosthesis interface was evaluated on all follow-up films using three
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contiguous acetabular zones delineated by DeLee and Charnley [16].
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Signs of cup migration and the appearance of osteolysis were evaluated on all
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follow-up films, in comparison to the immediate postoperative images. A component
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was considered to have migrated if change in position >3 mm or a change of the cup
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angle > 5o with respect to the immediate postoperative radiographs according to the
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criteria of Massin et al [17].Acetabular components were considered to be stable if
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they had no radiolucent lines or migration on the radiographs at the final follow-up.
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Gross PE wear was considered present when obvious concentric or eccentric femoral
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head penetration into the PE liner was observed on latest follow-up radiographs.
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Radiographic evaluation was performed by two orthopaedic surgeons, who were not
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involved in the surgery or the patient care.
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Descriptive statistics are presented as mean ± SD. Student’s unpaired t test
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was used to compare continuous values. Statistical analyses were performed using the
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PASW18.0 (SPSS release 18.0; SPSS Inc., Chicago, Illinois) with a level of
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significance set at p< 0.05.
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Results
137 The minimum follow-up time was 17.5 years, and the maximum follow-up
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time was 19 years, with a mean follow-up of 18,1 years. Of the 140 THAs, no
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acetabular component was revised or needed revision at the last follow-up because of
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aseptic loosening, mechanical failure or osteolysis. As shown in Table 2, HHS, OHS
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and ROM were dramatically improved in the latest follow-up.
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Ten patients required subsequent surgery. In one patient, the acetabular
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component was revised at 50 months for recurrent dislocation. Upon visual
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inspection, the revised acetabular component had extensive bone coverage. Two
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patients required two-stage exchange of both femoral stem and acetabular component
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because of deep infection, 6 and 7.5 years postoperatively. In the retrieved acetabular
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components, excellent bone coverage and penetration in the porous tantalum surface
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was noticed, and despite the infection, the acetabular component was stable at the
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time of removal. Aseptic loosening of the femoral stem occurred in 2 patients at 8 and
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13 years postoperatively, and required only revision of the femoral stem, as the
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acetabular component was stable and well-fixed. Three patients sustained a
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Vancouver B1 periprosthetic femoral fracture because of fall, and were treated with
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open reduction and internal fixation. One patient with superficial infection was treated
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with local debridement and antibiotics and one patient with wound hematoma was
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treated with wound drainage. One single case with early dislocation in one hip was
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treated by closed reduction without further incident. Deep vein thrombosis was seen
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in 2 hips and these were successfully treated conservatively. At the last follow-up, the
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survivorship with re-operation for any reason as end point was 92.8% and the
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survivorship for aseptic loosening as an end point was 100%.
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Acetabular component inclination in the initial postoperative radiograph was
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44,1° ± 4,3° (range 37.8° - 49.8°) and 44,4o ± 4,8o (range 37,2o – 50,6o) at the latest
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follow-up (p-value = 0.6). In the initial postoperative radiographs, periacetabular
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dome gaps were observed in 21 hips (15%).Thirteen of the gaps were measured less
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than 1 mm, and 8 of the gaps ranged from 1 to 3.5 mm. Six gaps were observed in
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zone 1, 12 gaps in zone 2 and 3 gaps in zone 3. Radiographic evidence of progressive
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gap filling was observed in all patients by 6 months. There was no further
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radiographic evidence of acetabular dome gaps at the latest follow-up. Moreover,
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there was no radiographic evidence of gross PE wear, backside wear, progressive
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radiolucencies, osteolytic lesions, acetabular fracture, or component subsidence
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(figures 1). At the latest follow-up, radiologic evaluation showed an increased bone
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density and remodeling and thickening of trabecular bone around the acetabular
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A B line at all 3 Charnley zones at 1 and 2 implant. One case had an acetabular radiolucent
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years but none at 5 years. This may be due to either patient positioning or gap filling.
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In the case with acetabular dome gaps, the acetabular component was deemed
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radiographically stable and the patient had no complaints of pain. No case of severe
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heterotopic ossification was observed.
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A Discussion
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Aseptic loosening of the acetabular component, induced by PE wear and
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periprosthetic osteolysis, is the most important limiting factor to the survival of
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uncemented THA [18-19]. In an effort to encounter the problem, acetabular
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components have evolved with the changes in design characteristics along with the
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surgical techniques. Monoblock cups are non-modular uncemented acetabular
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components in which the PE liner and shell are factory-preassembled into a single
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solid construct, diminishing the need for locking mechanisms and dome holes. The
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provided optimal liner-shell conformity, the elimination of liner-shell micromotion
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and the absence of screws and dome holes decrease the production of PE debris and
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prevent the debris access to the periacetabular regions of the pelvis, lowering the risk
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of periprosthetic osteolysis and the incidence of aseptic loosening [20]. The PE
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thickness is also an important factor as acetabular implants with thicker PE have less
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wear and better survival [21-22]. Porous tantalum possesses unique mechanical
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properties such as an interconnecting porous surface, which corresponds to 75% to
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80%, a mean pore diameter of 550 µm, a low modulus of elasticity and a high
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adherence, proliferation and differentiation and allowing for excellent primary
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stabilization of implants and broader use in orthopaedic surgery [7, 23]. The
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polyethylene liner is compression-molded into the metal shell to a depth of 1 - 2 mm,
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leaving 2 – 3 mm of porous tantalum for tissue ingrowth [24]. Merging the
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advantages of an elliptical monoblock design with the characteristics of porous
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tantalum, a porous tantalum monoblock cup has been used to improve longevity of
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cementless primary THA. Studies on tantalum monoblock cups using plain pelvic
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radiographs show a unique cancellous bone densification at the cup-bone interface,
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suggesting excellent ingrowth into the component [11, 24-26]. The lower rate of
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osteolysis observed with the use of UHMWPE, in comparison with the older
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generation PE, may be attributed to the fact that this monoblock construct allows for
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thicker PE even in small diameter cups and that the PE is press-molded in the TMT
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shell. In the present study, we focused on the long-term clinical and radiological
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results of porous tantalum monoblock acetabular component in primary hip surgery as
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we are among the first surgeons to use this implant worldwide.
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The excellent long-term results of this monoblock cup design may be
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compared to other long-term studies reporting on the performance of different
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monoblock cups with different ingrowth surfaces, metallic compositions, and
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elliptical or hemispherical shapes. No cup revision has been reported for 258 elliptical
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porous-coated titanium monoblock cups in 11 years of follow-up [27]. Excellent
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results have been reported for the non-modular porous-coated Morscher press-fit cup
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with 100% 10-year survival with no radiolucencies around the cup [28-29]. Another
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monoblock implant, the titanium-coated RM acetabular component, showed a 94%
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survival after 20 years of follow-up [30]. In a randomized controlled trial, porous
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tantalum monoblock cups demonstrated 100% survivorship, and significantly less
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radiolucency as compared to porous-coated titanium monoblock cups, at 12 years
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postoperatively [31]. However, a recent systematic review by Halma et al suggested
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that there is no significant difference in the rate of aseptic loosening, osteolysis or PE
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wear between monoblock and modular acetabular components [20]. The referred
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superiority of the monoblock cups may be attributed to the thicker PE and the
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elimination of micromotion and wear at the interface between the metallic shell and
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the PE liner.
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233
term results of the use of porous tantalum monoblock cups in THA [11-12, 24-26, 32-
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36]. In all studies, the survival of the porous tantalum acetabular component was
235
100% and excellent clinical outcomes were reported. However, there is only one
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study in the literature, reporting the long-term outcomes for this cup design, with a
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mean follow-up of 15.6 years [37]. In our study, we observed 0% rate of aseptic
238
loosening, migration or gross PE wear after a mean follow-up of 18.1 years (range
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17.5 – 19 years), coming in accordance with previously published studies. To the best
240
of our knowledge, this is the longest follow-up reported for primary THAs performed
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with trabecular metal cups. Ten patients were re-operated for reasons irrelevant to the
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stability and fixation of the acetabular component. Clinical data, expressed by HHS,
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OHS and ROM, support the radiological conclusions.
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Radiographic review of our data has shown early series of periacetabular
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dome gaps in 23 hips (16%). However, at 6 months of follow-up, there was a gap
246
filling, and no further radiographic evidence of periacetabular gaps was noted. The
247
long-term results of our study support the hypothesis that the initial postoperative
248
gaps at the bone–implant interface, do not influence long-term stability. We suggest
249
that the osteoconductive properties of tantalum metal allows for the resolution of most
250
line-to-line component to host bone differences found after primary THA.
251
Komarasamy et al. also reported a high incidence (22%) of polar gaps in their series.
252
All gaps were filled at the last follow-up [36]. Similarly, Gruen et al reported
253
radiographic evidence of periacetabular gaps using the same acetabular component
254
with complete gap filling at 2 years [35]. In studies, where some initial postoperative
255
periacetabular dome gaps persisted for more than 2 years, the longevity of the implant
256
was not compromised [26, 32]. The gaps seem to relate with the surgeon's ability to
257
seat the acetabular component completely.
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The use of porous tantalum acetabular components in THA has several
259
disadvantages. Implantation of the specific acetabular component might be
260
demanding as dome contact cannot be visualized because of the lack of screw holes
261
on the dome and the presence of the liner. When inserting the elliptical socket, it is
262
necessary to seat the cup into the acetabular periphery so that it is circumferentially
263
centered before impacting the cup medially. This seating prevents the rim of the cup
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impinging on the acetabular mouth and migrating superiorly when the cup is
265
impacted. Furthermore, the high cost of the implant is the reason why we did not use
266
this cup in elderly people. Finally, the lack of modularity does not allow isolated liner
267
exchange. The specific implant is no longer available in the market. The present study has several limitations. First, this is a prospective
269
observational case series without any control group with cups of a different design. A
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second limitation was related to the use of simple radiographs to evaluate osteolysis.
271
Radiographs typically underestimate the true incidence and extent of periacetabular
272
osteolysis, as computed tomographic (CT) scan is the modality of choice to detect
273
such lesions. However, studies by Meneghini and Moen showed no evidence of
274
osteolysis on CT scans of porous tantalum monoblock acetabular cups after a mean of
275
7.7 years and 10.3 years, respectively [33, 38]. Nevertheless, overproduction of
276
artifacts by porous tantalum may impair the ability of CT scan to assess osteolysis and
277
bone ingrowth around the component [39]. Finally, only the gross PE wear was
278
assessed while the linear and volumetric PE wear analysis with more sophisticated
279
methods was not performed, possibly underestimating the presence of any subtle wear
280
[40-42].
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In conclusion, the use of porous tantalum acetabular monoblock components
282
in primary THA has shown excellent long-term clinical and radiographic outcome.
283
The revision rate for aseptic loosening in the 17.5 to 19 years of follow-up was 0%.
284
No radiolucencies, gross PE wear and acetabular cup migration were observed,
285
findings that confirm the effectiveness of this implant and support the theoretical
286
advantages of tantalum metal. Potential disadvantages of this trabecular metal
287
monoblock cup do not seem to influence the survival of the surgery.
AC C
288
EP
281
289
Acknowledgements
290
This research did not receive any specific grant from funding agencies in the public,
291
commercial, or not-for-profit sectors.
292
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ACCEPTED MANUSCRIPT References
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1. Shan L, Shan B, Graham D, Saxena A. Total hip replacement: a systematic review and meta-analysis on mid-term quality of life. Osteoarthritis Cartilage. 2014; (22): 389-406. 2. Ollivere B, Wimhurst JA, Clark IM, Donell ST. Current concepts in osteolysis. J Bone Joint Surg Br. 2012; (94): 10-15. 3. Purdue PE, Koulouvaris P, Potter HG, Nestor BJ, Sculco TP. The cellular and molecular biology of periprosthetic osteolysis. Clin Orthop Relat Res. 2007; (454): 251-261. 4. Grelsamer RP. Applications of porous tantalum in total hip arthroplasty. J Am Acad Orthop Surg. 2007; (15): 137; author reply 137-138. 5. Patil N, Lee K, Goodman SB. Porous tantalum in hip and knee reconstructive surgery. J Biomed Mater Res B Appl Biomater. 2009; (89): 242-251. 6. Sculco TP. The acetabular component: an elliptical monoblock alternative. J Arthroplasty. 2002; (17): 118-120. 7. Paganias CG, Tsakotos GA, Koutsostathis SD, Macheras GA. Osseous integration in porous tantalum implants. Indian J Orthop. 2012; (46): 505-513. 8. Christie MJ. Clinical applications of Trabecular Metal. Am J Orthop (Belle Mead NJ). 2002; (31): 219-220. 9. Levine BR, Sporer S, Poggie RA, Della Valle CJ, Jacobs JJ. Experimental and clinical performance of porous tantalum in orthopedic surgery. Biomaterials. 2006; (27): 4671-4681. 10. Cohen R. A porous tantalum trabecular metal: basic science. Am J Orthop (Belle Mead NJ). 2002; (31): 216-217. 11. 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): 705-709. 12. Xenakis TA, Macheras GA, Stafilas KS, Kostakos AT, Bargiotas K, Malizos KN. Multicentre use of a porous tantalum monoblock acetabular component. Int Orthop. 2009; (33): 911-916. 13. Harris WH. Traumatic arthritis of the hip after dislocation and acetabular fractures: treatment by mold arthroplasty. An end-result study using a new method of result evaluation. J Bone Joint Surg Am. 1969; (51): 737-755. 14. Dawson J, Fitzpatrick R, Carr A, Murray D. Questionnaire on the perceptions of patients about total hip replacement. J Bone Joint Surg Br. 1996; (78): 185-190. 15. Murray DW. The definition and measurement of acetabular orientation. J Bone Joint Surg Br. 1993; (75): 228-232. 16. DeLee JG, Charnley J. Radiological demarcation of cemented sockets in total hip replacement. Clin Orthop Relat Res. 1976: 20-32. 17. Massin P, Schmidt L, Engh CA. Evaluation of cementless acetabular component migration. An experimental study. J Arthroplasty. 1989; (4): 245-251. 18. Hailer NP, Garellick G, Karrholm J. Uncemented and cemented primary total hip arthroplasty in the Swedish Hip Arthroplasty Register. Acta Orthop. 2010; (81): 34-41. 19. Haidukewych GJ. Osteolysis in the well-fixed socket: cup retention or revision? J Bone Joint Surg Br. 2012; (94): 65-69. 20. Halma JJ, Vogely HC, Dhert WJ, Van Gaalen SM, de Gast A. Do monoblock cups improve survivorship, decrease wear, or reduce osteolysis in uncemented total hip arthroplasty? Clin Orthop Relat Res. 2013; (471): 3572-3580.
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21. Zhu YH, Chiu KY, Tang WM. Review Article: Polyethylene wear and osteolysis in total hip arthroplasty. J Orthop Surg (Hong Kong). 2001; (9): 91-99. 22. Lee PC, Shih CH, Chen WJ, Tu YK, Tai CL. Early polyethylene wear and osteolysis in cementless total hip arthroplasty: the influence of femoral head size and polyethylene thickness. J Arthroplasty. 1999; (14): 976-981. 23. 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): 907-914. 24. Macheras GA, Papagelopoulos PJ, Kateros K, Kostakos AT, Baltas D, Karachalios TS. Radiological evaluation of the metal-bone interface of a porous tantalum monoblock acetabular component. J Bone Joint Surg Br. 2006; (88): 304309. 25. Mulier M, Rys B, Moke L. Hedrocel trabecular metal monoblock acetabular cups: mid-term results. Acta Orthop Belg. 2006; (72): 326-331. 26. 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): 159-166. 27. Poultsides LA, Sioros V, Anderson JA, Bruni D, Beksac B, Sculco TP. Ten- to 15-year clinical and radiographic results for a compression molded monoblock elliptical acetabular component. J Arthroplasty. 2012; (27): 1850-1856. 28. Garavaglia G, Lubbeke A, Barea C, Roussos C, Peter R, Hoffmeyer P. Tenyear results with the Morscher press-fit cup: an uncemented, non-modular, porouscoated cup inserted without screws. Int Orthop. 2011; (35): 957-963. 29. Gwynne-Jones DP, Garneti N, Wainwright C, Matheson JA, King R. The Morscher Press Fit acetabular component: a nine- to 13-year review. J Bone Joint Surg Br. 2009; (91): 859-864. 30. Ihle M, Mai S, Pfluger D, Siebert W. The results of the titanium-coated RM acetabular component at 20 years: a long-term follow-up of an uncemented primary total hip replacement. J Bone Joint Surg Br. 2008; (90): 1284-1290. 31. Wegrzyn J, Kaufman KR, Hanssen AD, Lewallen DG. Performance of Porous Tantalum vs. Titanium Cup in Total Hip Arthroplasty: Randomized Trial with Minimum 10-Year Follow-Up. J Arthroplasty. 2015; (30): 1008-1013. 32. Noiseux NO, Long WJ, Mabry TM, Hanssen AD, Lewallen DG. Uncemented porous tantalum acetabular components: early follow-up and failures in 613 primary total hip arthroplasties. J Arthroplasty. 2014; (29): 617-620. 33. 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): 382-386. 34. 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): 35-40. 35. Gruen TA, Poggie RA, Lewallen DG, Hanssen AD, Lewis RJ, O'Keefe TJ, et al. Radiographic evaluation of a monoblock acetabular component: a multicenter study with 2- to 5-year results. J Arthroplasty. 2005; (20): 369-378. 36. 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): 320-325. 37. De Martino I, De Santis V, Sculco PK, D'Apolito R, Poultsides LA, Gasparini G. Long-Term Clinical and Radiographic Outcomes of Porous Tantalum Monoblock
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Acetabular Component in Primary Hip Arthroplasty: A Minimum of 15-Year FollowUp. J Arthroplasty. 2016; (31): 110-114. 38. Meneghini RM, Ford KS, McCollough CH, Hanssen AD, Lewallen DG. Bone remodeling around porous metal cementless acetabular components. J Arthroplasty. 2010; (25): 741-747. 39. Levi AD, Choi WG, Keller PJ, Heiserman JE, Sonntag VK, Dickman CA. The radiographic and imaging characteristics of porous tantalum implants within the human cervical spine. Spine (Phila Pa 1976). 1998; (23): 1245-1250; discussion 1251. 40. Martell JM, Berdia S. Determination of polyethylene wear in total hip replacements with use of digital radiographs. J Bone Joint Surg Am. 1997; (79): 1635-1641. 41. McCalden RW, Naudie DD, Yuan X, Bourne RB. Radiographic methods for the assessment of polyethylene wear after total hip arthroplasty. J Bone Joint Surg Am. 2005; (87): 2323-2334. 42. Rahman L, Cobb J, Muirhead-Allwood S. Radiographic methods of wear analysis in total hip arthroplasty. J Am Acad Orthop Surg. 2012; (20): 735-743.
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ACCEPTED MANUSCRIPT FIGURE CAPTIONS
413
Figure 1A-B. Postoperative (A) and 18-year follow-up (B) anteroposterior radiograph
414
of the right hip after THA using the porous tantalum monoblock acetabular
415
component. No evidence of gross PE wear, backside wear, radiolucencies, osteolytic
416
lesions, acetabular fracture or component migration is observed.
RI PT
411 412
417
Figure 2A-F. Postoperative radiographs at (A) 2, (B) 6, (C) 12 weeks, (D) 6 months,
419
(E) 3 years and (F) 18 years of a TMT cup. A periacetabular osteoarthritic cyst at
420
zone 1 has been progressively filled 1 year after total hip arthroplasty.
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TABLE 1. Demographic characteristics of the study cohort.
424
DDH: Developmental dysplasia of hip. AVN: Avascular necrosis. RA: Rheumatoid
425
arthritis
No of patients
128
No of THAs
140
Male / Female
38 / 90
Mean age (years)
60,4 ± 12,6
RI PT
426 427 428
Reason for THA
SC
(range 24 – 72) Primary OA: 104
AVN: 9 RA: 2 429
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430
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DDH: 25
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TABLE 2.HHS, OHS and ROM of the patients, pre-operatively, after 1 year of
432
follow-up and at the latest follow-up.
433 1 year follow up
Latest follow-up
p-value
HHS
44.4 ± 13.4
95.4 ± 5.2
95.2 ± 6.9
< 0.0001
OHS
15.8 ± 6.3
43.1 ± 4.6
41.2 ± 2.5
< 0.0001
ROM (flexion)
72.5o ± 13.6o
102.5o ± 12.7o
100.5o ± 12.4o
< 0.0001
ROM (abduction)
15.7o ± 3.2o
40.9o ± 3.9o
40.1o ± 3.1o
< 0.0001
434
AC C
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TE D
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SC
435
RI PT
Preoperative
16
ACCEPTED MANUSCRIPT FIGURE 1.
B
AC C
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SC
RI PT
A
ACCEPTED MANUSCRIPT FIGURE 2.
B
D
E
C
AC C
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RI PT
A
F