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Scientific Articles: Craig J. Della Valle, Nathan W. Mesko, Laura Quigley, Aaron G. Rosenberg, Joshua J. Jacobs, and Jorge O. Galante Primary Total Hip Arthroplasty with a Porous-Coated Acetabular Component. A Concise Follow-up, at a Minimum of Twenty Years, of Previous Reports J Bone Joint Surg Am 2009; 91: 1130-1135 [Abstract] [Full text] [PDF]

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Dr. Della Valle and colleagues respond to Mr. Whitehouse and Mr. Bannister

Craig J. Della Valle, MD, Aaron G. Rosenberg, MD; Joshua J. Jacobs, MD; Jorge O. Galante, MD   (5 August 2009)

Definition of Failure

Michael R. Whitehouse, MBChB, BSc, M(ScOrthEng), MRCS(Eng), G.C. Bannister, MD, FRCS   (5 August 2009)

Dr. Della Valle and colleagues respond to Drs. Schreurs and de Kam

Craig J. Della Valle, MD, Nathan W. Mesko, MD; Laura Quigley, MS; Aaron G. Rosenberg, MD; Joshua J. Jacobs, MD; Jorge O. Galante, MD   (30 June 2009)

Primary Total Hip Arthroplasty with a Porous-Coated Acetabular Component: Outcome in young patients?

B. Willem Schreurs, MD, PhD, Daniel de Kam, MD   (30 June 2009)

Dr. Della Valle and colleagues respond to Mr. Whitehouse and Mr. Bannister 5 August 2009
Craig J. Della Valle, MD, Associate Professor Rush University Medical Center, Chicago, Illinois, Aaron G. Rosenberg, MD; Joshua J. Jacobs, MD; Jorge O. Galante, MD Send letter to journal: Re: Dr. Della Valle and colleagues respond to Mr. Whitehouse and Mr. Bannister craigdv{at}yahoo.com Craig J. Della Valle, MD, et al.	We thank Mr. Whitehouse and Bannister for their interest in our work. The primary reason for our reviewing this series of patients was to determine the durability of cementless fixation for acetabular reconstruction in primary total hip arthroplasty as we are unaware of any other series that report these results at a minimum of twenty years. Nonetheless, we reported in our manuscript survivorship with, “a reoperation on the hip for any problem related to the acetabular metal shell (e.g. loosening, polyethylene wear or periacetabular osteolysis)…”as one of the endpoints; survivorship with this endpoint was 86% at twenty years. Thus, in contradistinction to your concern regarding reporting on, “one part of one component”, survivorship for acetabular component and liner was reported. We also went on to include a description of an additional eight hips in which a liner change had been recommended by one of us, but not yet performed. Further, in response to your concern of a, “trend in orthopaedics...to report only the survival of one component of a construct” the survivorship of the femoral component was also described in our report. Given the popularity of cementless fixation of the acetabular component in North America, the lack of prior data at the time point described and the known shortfalls of the first generation, non-circumferentially porous coated femoral component used in this early series, a focus on the acetabular component seems warranted. We would agree that the lack of complete radiographic follow-up is a limitation of this work. Despite our concerted efforts to encourage patients to return for radiographic follow-up, many simply will not as they are oftentimes of an advanced age and or asymptomatic. Survivorship analysis, however, does correct for this to a certain extent, with the reported 95% confidence intervals that widen, as the number of patients from the original data set are lost. Finally, Mr. Whitehouse and Bannister in their letter represent survival rates without taking into account censored data and resultant effects on confidence intervals. Understandably, since computing survival estimates with error estimates (i.e. confidence intervals) is nearly impossible without the raw data, but use of a “worst case scenario” is overly simplistic and biases interpretation in a way that we feel misrepresents the data. We do not intend to portray the HG-1 cup as an implant free of problems; it had a poor locking mechanism, a less than ideal (rough) concave surface and, by modern standards, a sub-optimal bearing surface that all contributed to a high rate of wear related problems. Fixation, however, has been impressive. It is our hope that with improvements in bearing technology and contemporary cup design, the rate of re-operation for wear related sequalae will decrease in the future with a lower rate of re-operation for our patients.
Definition of Failure 5 August 2009
Michael R. Whitehouse, MBChB, BSc, M(ScOrthEng), MRCS(Eng), Hip Fellow University of Bristol, Bristol, United Kingdom, G.C. Bannister, MD, FRCS Send letter to journal: Re: Definition of Failure mikerwhitehouse{at}gmail.com Michael R. Whitehouse, MBChB, BSc, M(ScOrthEng), MRCS(Eng), et al.	To the Editor: We read with interest the recent article by Della Valle et al. (1). There are a number of points we feel need to be raised with regard to the authors’ conclusions. The authors report a 96% survival rate at their final follow-up with aseptic loosening as the defined end point. As the authors themselves point out, this is not the major mode of failure of this design of acetabular component. There is a trend in orthopaedic surgery for investigators to report the survival of one component of a construct. But this paper is even more selective, identifying one part of one component, the metal shell. Assuming best-case analysis, the data presented in Table II indicates a survival of the acetabular component of 65% at 20 years. Isolated liner exchange is associated with a high risk of subsequent dislocation (2,3). The percentages presented in the paper are based on an assumed population available for study of 204 patients (184 patients). Only 124 hips in 111 patients were available for study with 69 deaths (75 hips) and 4 patients lost to follow up (5 hips). Thirty-two percent of these patients did not have radiographs performed, therefore silent osteolysis and wear could not be assessed. As silent osteolysis is an important failure mode that currently makes up the majority of our revision burden, we feel this cohort is significant (4). Indeed, the associated loss of bone stock with osteolysis means that it is a more serious failure mode than the more predictable aseptic loosening of the cemented cup, failure of which stimulated this design. According to the date presented, 10 out of 124 shells had been revised at 20 years (92% survival); a further 21 liners had been revised or revision had been recommended in this group (75% survival including revised shells). Excluding patients without radiographs, this gives a 43.5% known survival on the basis of a worst-case analysis. Seventy-five hips had clinical and radiographic evaluation (60.5% survival worst-case analysis) and 25 of these demonstrated osteolysis, indicating a likely need for revision (40.3% survival). It is difficult to extract how many of these overlap with hips having a liner exchange performed or recommended. We would suggest that revision for any cause or the impending need for revision would give a more helpful representation of outcome when reporting on total joint replacement procedures. The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated. References 1. Della Valle CJ, Mesko NW, Quigley L, Rosenberg AG, Jacobs JJ, Galante JO. Primary total hip replacement with a porous-coated acetabular component. A concise follow-up, at a minimum of twenty years, of previous reports. J Bone Joint Surg Am. 2009;91:1130-5. 2. Blom AW, Astle L, Loveridge J, Learmonth ID. Revision of an acetabular liner has a high risk of dislocation. J Bone Joint Surg Br. 2005;87:1636-8. 3. Lie SA, Hallan G, Furnes O, Havelin LI, Engesaeter LB. Isolated acetabular liner exchange compared with complete acetabular component revision in revision of primary uncemented acetabular components: a study of 1649 revisions from the Norwegian Arthroplasty Register. J Bone Joint Surg Br. 2007;89:591-4. 4. Utting MR, Raghuvanshi M, Amirfeyz R, Blom AW, Learmonth ID, Bannister GC. The Harris-Galante porous-coated, hemispherical, polyethylene-lined acetabular component in patients under 50 years of age: a 12- to 16-year review. J Bone Joint Surg Br. 2008;90:1422-7.
Dr. Della Valle and colleagues respond to Drs. Schreurs and de Kam 30 June 2009
Craig J. Della Valle, MD, Associate Professor of Orthopaedic Surgery Rush University Medical Center, Nathan W. Mesko, MD; Laura Quigley, MS; Aaron G. Rosenberg, MD; Joshua J. Jacobs, MD; Jorge O. Galante, MD Send letter to journal: Re: Dr. Della Valle and colleagues respond to Drs. Schreurs and de Kam craigdv{at}yahoo.com Craig J. Della Valle, MD, et al.	We thank Drs. Schreurs and de Kam for their interest in our work. As they point out in their letter, 10 of the 204 acetabular components were revised; eight of those at the time of revision surgery were found to be well-fixed and two were loose. Four of the eight well- fixed components were removed for the treatment of osteolysis. While we agree that osteolysis can lead to loosening, these cups were not,in fact, found to be loose at the time of revision; therefore, they were not considered to have been failures for our survivorship analysis which considered acetabular component loosening as an endpoint. However, they were considered as failures for the survivorship analysis that considered a reoperation on the hip for a problem related to the acetabular component. Looking back at the cases that were revised for osteolysis, we would not currently remove those components, but rather prefer to use particulate graft around the component and perform a modular polyethylene liner exchange. Regarding the results of cementless acetabular reconstruction in younger patients, our cohort is actually quite unique, as the mean patient age at the time of surgery was 52 years. Thus we believe that our paper does yield some insight into this question. As we have continued to follow this cohort, the surviving patients are not unexpectedly the patients who underwent surgery at a younger age. In the subset of patients who were less than 50 years old at the time of surgery, only one patient (who had undergone bilateral total hips) was lost to follow-up. In terms of the age-specific details of those who underwent revisions of the acetabular component, six of the ten revisions were in patients who were less than 50 years old at the time of the index arthroplasty. Four of these six revisions were performed for loosening (two patients) or osteolysis (two patients), with the remaining two being revised secondary to infection. These six revisions were performed at a mean of 196.3 months postoperatively; if the two infections are excluded, the mean time to revision was 179.8 months (range 123-230 months). Table III in the paper, which stratifies patients by age, shows the strong effect of age on the prevalence of osteolysis and the performance of modular polyethylene liner exchanges with the majority of wear related issues identified in patients who were less than 50 years old at the time of surgery. It is important to stress that this experience is with a first generation device, and it is our hope that the wear-related complications observed in this series will be decreased with modern cementless designs that have incorporated improvements that include better polyethylene congruency and locking mechanisms and bearing surfaces (such as cross-linking).
Primary Total Hip Arthroplasty with a Porous-Coated Acetabular Component: Outcome in young patients? 30 June 2009
B. Willem Schreurs, MD, PhD, Orthopedic Surgeon Department of Orthopedics, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands, Daniel de Kam, MD Send letter to journal: Re: Primary Total Hip Arthroplasty with a Porous-Coated Acetabular Component: Outcome in young patients? b.schreurs{at}orthop.umcn.nl B. Willem Schreurs, MD, PhD, et al.	To the Editor: We read the paper by Della Valle and colleagues (1) with great interest and we congratulate the team on their excellent results. Their minimum 20 years survival data using a metal shell is impressive with only 10 of 204 acetabular components being revised. We would question, however, their interpretation that only two of these 10 cups were revised for aseptic loosening. It is difficult to accept that cups which have been removed to treat acetabular osteolysis, which is an essential part of the aseptic loosening process, were not considered as aseptic failures. We believe the authors can provide additional valuable information by also reporting the outcomes of hips in younger patients. At the moment, there are no long-term reports on the outcome of non-cemented cups in young patients at a minimum follow-up of 20 years. The authors have a large group of patients in their study (79 hips) who underwent THA when they were younger than 50. It would be very interesting if the authors can provide more detailed data of this specific group. From the paper it can be inferred that, of these 79 hips, 10 had a liner exchange (10/79 = 13%), and osteolysis was seen in at least 26 of the 79 hips (33%). We would surmise that, with further follow up, these percentages will increase with time. For the whole study group of 124 hips available at a minimum of 20 years, only 60% of the patients had a radiograph available. As most liner exchanges are seen in the younger patients, it can also be inferred that the majority of of patients who underwent a liner exchange(8 for the whole group) were from the younger age group. Based on this calculation and these assumptions, it seems that at least over 50% of the patients under 50 years will have cup wear or osteolysis problems. It is also unknown how many of the patients lost to follow up were from the under 50 age group and how many of the 10 revisions were performed in this group. It would be very helpful if the authors could provide this additional information, so that the outcomes of non-cemented cups in young patients can be compared to the published results of cemented cups in young patients that are already available in literature. The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated. Reference 1. Della Valle CJ, Mesko NW, Quigley L, Rosenberg AG, Jacobs JJ, Galante JO. Primary total hip arthroplasty with a porous-coated acetabular component. A concise follow-up, at a minimum of twenty years, of previous reports. J Bone Joint Surg Am. 2009;91:1130-5.

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