JBJS welcomes reader comments on published articles. Letters to the Editor are reviewed by JBJS editors but are not peer-reviewed. To submit your letter, please follow the "submit a response" link that appears in the content box at the upper right of the full text of the article.

Letters to the Editor to:

Scientific Articles:
Steven H. Goldberg, Robert M. Urban, Joshua J. Jacobs, Graham J.W. King, Shawn W. O'Driscoll, and Mark S. Cohen
Modes of Wear After Semiconstrained Total Elbow Arthroplasty
J Bone Joint Surg Am 2008; 90: 609-619 [Abstract] [Full text] [PDF]
*Letters to the Editor: Submit a response to this article

Electronic letters published:

[Read Letter to the Editor] Dr. Urban and colleagues respond to Dr. Morrey
Robert M Urban, Steven H. Goldberg, Joshua J. Jacobs, Graham J.W. King, Shawn W. O'Driscoll, Mark S. Cohen   (10 September 2008)
[Read Letter to the Editor] Wear of the Elbow Prosthesis Articulation is a Complex, Three Body Problem
Bernard F Morrey   (10 September 2008)

Dr. Urban and colleagues respond to Dr. Morrey 10 September 2008
Previous Letter to the Editor Top
Robert M Urban,
Associate Professor
Department of Orthopedic Surgery, Rush University Medical Center,
Steven H. Goldberg, Joshua J. Jacobs, Graham J.W. King, Shawn W. O'Driscoll, Mark S. Cohen

Send letter to journal:
Re: Dr. Urban and colleagues respond to Dr. Morrey

robert_urban{at}rush.edu Robert M Urban, et al.

We agree with Dr. Morrey that cause and effect are difficult to establish in a retrospective, observational study of a subset of retrieved total elbow arthroplasty prostheses. A multi-center study with several elbow arthroplasty surgeons was needed to generate a sufficient number of implants to make observations regarding modes of wear in total elbow arthroplasty. Rather than determining cause and effect, the primary purpose of the study was to describe that osteolysis and aseptic loosening occur in total elbow replacement and that these processes are similar to what has been more extensively described with total hip and knee replacements and that osteolysis and aseptic loosening are related to particular modes of wear. Dr. Morrey asks “Did bushing wear cause lysis that allowed the fracture or did the fracture produce metallic particles that accelerated bushing wear?” Our systematic review of serial radiographs from initial postoperative radiographs through the final radiographs prior to the revision arthroplasty procedure that yielded the implants has led us to believe that in certain cases bushing wear preceded and contributed to implant fracture. The typical pattern in cases of component fracture was one of periarticular osteolysis creating a stress riser between unsupported and well-fixed sections of the stem. For example, Implant 12 which exhibited a humeral fracture 62 months post- implantation had substantial peri-articular osteolysis (Figure 1) leaving a well-fixed proximal humeral stem and an unsupported distal humeral stem that predisposed to humeral stem fracture due to cantilever bending forces (Figure 2). The anteroposterior radiographs exhibited thinned bushings with wear of the arthroplasty in valgus.

Dr. Morrey was also correct in stating that, based on the design of this study, it cannot be determined if bushing wear is the primary or a secondary cause for osteolysis and loosening. Cement and metal particles generated from a loosened precoated stem and acting as third bodies in bushing wear was but one mode of wear identified in our study. Similar to retrieval studies of other joint arthroplasties, the elbow implants we analyzed exhibited multiple modes of wear and damage, including irreversible plastic deformation of the polyethylene, indicating that osteolysis and aseptic loosening are multifactorial processes.

Finally, we appreciate Dr. Morrey’s correcting the terminology to reflect the accurate description of the generations of the Coonrad-Morrey implant.


Fig. 1. 54 months post total elbow arthroplasty, there is severe periarticular osteolysis involving both the cement-prosthesis and bone-cement interfaces of the ulna and humerus. Significant bushing wear is evidenced by the prosthesis articulation exhibiting a valgus alignment beyond the amount intended by the manufacturer.


Fig. 2. 62 months post total elbow arthroplasty, a humeral stem fracture has occurred due to cantilever bending forces at the junction of the well-fixed proximal humeral stem and the distal portion of the stem that has experienced a loss of support from the progressive osteolysis. At revision surgery, the proximal humeral stem was confirmed to be well-fixed and the ulnar stem and the humeral prosthesis distal to the fracture were grossly loose. There was severe asymmetric polyethylene bushing wear, thinning, pitting, and metal debris embedded within the bushing.
Wear of the Elbow Prosthesis Articulation is a Complex, Three Body Problem 10 September 2008
Next Letter to the Editor Top
Bernard F Morrey,
Orthopedic Surgeon
Mayo Clinic, Rochester MN

Send letter to journal:
Re: Wear of the Elbow Prosthesis Articulation is a Complex, Three Body Problem

morrey.bernard{at}mayo.edu Bernard F Morrey

To the Editor:

The article “Modes of Wear After Semiconstrained Total Elbow Arthroplasty” by Goldberg et al.(1) is a worthwhile contribution to our understanding of the wear patterns of this particular design of elbow joint replacement. The authors are to be commended for their description and analysis of this problem. Unfortunately, in my opinion, one very important feature of this complex problem was not adequately discussed.

Table 2 lists an array of problems including four with implant fracture that makes it extremely difficult to determine cause and effect. Did bushing wear cause lysis that allowed the fracture or did the fracture produce metallic particles that accelerated bushing wear? Further, the analysis documents that 12 of 14 patients in their series had pre-coat ulnar surface preparation. It is well described in the orthopedic literature that a pre-coat surface renders a cemented implant vulnerable to osteolysis and failure(2).The most notable feature of a loose pre-coat cemented surface is the rapid and aggressive osteolysis around the stem which is due to an extensive release of debris particles(3).The radiographic appearance of the patient described in Figure 2B is classic for this type of debonding failure and subsequent osteolysis. This phenomenon clearly plays a role in generating debris that finds its way into the joint causing third body wear. The analysis has emphasized the specific design of this articulation and the manner in which it is vulnerable to edge loading. However,9 of the patients have failures consistent with third body wear as a cause or effect of the failure (Table 2). The specific point is that we have no data that allows us to conclude a worn bushing alone leads to sufficient osteolysis to cause stem loosening. This is important since in our experience of almost 1000 replacements, we have not yet once been able to document a loose stem solely because of osteolysis related specifically to bushing wear(4).

Finally, to be accurate in terminology, the first two generations described in Table 1 were not Coonrad-Morrey implants. The manufacturer considers the beads to be second generation of ulnar surface preparation of the Coonrad/Morrey design, and the pre-coat the third generation of surface preparation. Regardless, the authors are to be commended for their analysis and for calling attention to potential failure modes of this implant design

The author did not receive any outside funding or grants in support of his research for or preparation of this work. The author, or a member of his immediate family, received, in any one year, payments or other benefits in excess of $10,000 or a commitment or agreement to provide such benefits from a commercial entity (Zimmer, Warsaw Id). 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 author, or a member of his immediate family, is affiliated or associated.

References:

1.Steven H. Goldberg, Robert M. Urban, Joshua J. Jacobs, Graham J.W. King, Shawn W. O'Driscoll, and Mark S. Cohen Modes of Wear After Semiconstrained Total Elbow Arthroplasty J Bone Joint Surg Am 2008; 90: 609-619

2. Sylvain GM, Kassab S, Coutts R, Santore R: Early failure of a roughened surface, precoated femoral component in total hip arthroplasty. J Arthroplasty 16(2):141-148, 2001.

3. Ong A, Wong KL, Lai M, Garino JP, Steinberg ME: Early failure of precoated femoral components in primary total hip arthroplasty. J Bone Joint Surg 84:786-792, 2002.

4. Lee BP, Adams RA, Morrey BF: Polyethylene wear after total elbow arthroplasty. J Bone Joint Surg 76A(5):1080-1087, 2005.