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10 Letters to the Editor published for 6 different topic sources.

Articles			Letters
	Prenatal Diagnosis and Treatment: Prenatal Diagnosis and Treatment of Congenital Differences of the Hand and Upper Limb Bae et al. (1 July 2009) [Full text] [PDF]		Prenatal Diagnosis of Undefined Soft Tissue Tumors Lukas A. Lisowski   (28 October 2009) Read every Letter to the Editor related to this article
	Scientific Articles: Resident Duty-Hour Reform Associated with Increased Morbidity Following Hip Fracture Browne et al. (1 September 2009) [Abstract] [Full text] [PDF]		Dr. Browne and colleagues respond to Mr. O'Neill James A. Browne, MD, et al.   (28 October 2009) Resident Duty Hour Reform Associated with Increased Recording of Morbidity Following Hip Fracture Barry J. O'Neill   (28 October 2009) Read every Letter to the Editor related to this article
	Scientific Articles: Functional Outcomes for Unstable Distal Radial Fractures Treated with Open Reduction and Internal Fixation or Closed Reduction and Percutaneous Fixation. A Prospective Randomized Trial Rozental et al. (1 August 2009) [Abstract] [Full text] [PDF]		Dr. Rozental responds to Mr. Holmes and colleagues Tamara D. Rozental, MD   (29 October 2009) Group Homogeneity William JM Holmes, MBChB, MRCSEd, et al.   (29 October 2009) Read every Letter to the Editor related to this article
	Scientific Articles: Effect of Innominate and Femoral Varus Derotation Osteotomy on Acetabular Development in Developmental Dysplasia of the Hip Spence et al. (1 November 2009) [Abstract] [Full text] [PDF]		Surgical Treatment of Developmental Dysplasia of the Hip - Our Experience Zoran S. Vukasinovic, et al.   (17 November 2009) Read every Letter to the Editor related to this article
	Scientific Articles: Complications of Titanium and Stainless Steel Elastic Nail Fixation of Pediatric Femoral Fractures Wall et al. (1 June 2008) [Abstract] [Full text] [PDF]		Dr. Wall and colleagues respond to Dr. Thakkar Eric J. Wall, MD, et al.   (3 November 2009) Complication Comparison of Titanium and Stainless Steel Elastic Nails Navin N. Thakkar   (3 November 2009) Read every Letter to the Editor related to this article
	Scientific Articles: Extracellular Matrix Bioscaffolds for Orthopaedic Applications. A Comparative Histologic Study Valentin et al. (1 December 2006) [Abstract] [Full text] [PDF]		Dr. Badylak and Ms. Valentin respond to Dr. James and colleagues Stephen F. Badylak, DVM, PhD, MD, et al.   (18 November 2009) TissueMend is not chemically crosslinked nor does it elicit a classic foreign body response Kenneth S. James, PhD, et al.   (18 November 2009) Read every Letter to the Editor related to this article

Prenatal Diagnosis and Treatment: Prenatal Diagnosis and Treatment of Congenital Differences of the Hand and Upper Limb Bae et al. (1 July 2009) [Full text] [PDF] Prenatal Diagnosis and Treatment of Congenital Differences of the Hand and Upper... Prenatal Diagnosis of Undefined Soft Tissue Tumors 28 October 2009 Lukas A. Lisowski, Orthopaedic Surgeon The Royal Infirmary of Edinburgh, Scotland Send letter to journal: Re: Prenatal Diagnosis of Undefined Soft Tissue Tumors lalisowski{at}gmail.com Lukas A. Lisowski To the Editor: In the article by Bae et al. (1), a nice overview is given on the prenatal diagnosis of structural hand and upper limb malformations. Recommendations on prenatal counseling of parents having a child with such a deformation will become increasingly important as more deformities are expected to be diagnosed prenatally by improved diagnostic techniques. My only concern is how parents should be counseled on prenatally detected undefined soft tissue tumors. This topic is not addressed in Bae's paper. As the diagnosis is mostly based on clinical findings, radiography, and fine needle biopsy or tissue sampling, its ideal management is controversial and difficult. How should future recommendations be defined? The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family 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 author, or a member of his immediate family, is affiliated or associated. References 1. Bae DS, Barnewolt CE, Jennings RW. Prenatal diagnosis and treatment of congenital differences of the hand and upper limb. J Bone Joint Surg Am. 2009;91 Suppl 4:31-9.

Scientific Articles: Resident Duty-Hour Reform Associated with Increased Morbidity Following Hip Fracture Browne et al. (1 September 2009) [Abstract] [Full text] [PDF] Resident Duty-Hour Reform Associated with Increased Morbidity Following Hip Fracture Dr. Browne and colleagues respond to Mr. O'Neill 28 October 2009 James A. Browne, MD, Orthopaedic Fellow in Adult Reconstruction Mayo Clinic, Chad Cook, PhD, MBA, PT; Steven A. Olson, MD; Michael P. Bolognesi, MD Send letter to journal: Re: Dr. Browne and colleagues respond to Mr. O'Neill browne_james{at}yahoo.com James A. Browne, MD, et al. We thank Mr. O’Neill for his interest in our paper and for sharing his own perspective on duty-hour restrictions. We agree that the delivery of healthcare is a complex process and that patient care depends on many variables. While interesting, the assertion that residents now have more time and energy to document co-morbidities and complications for their patients is pure speculation. Conversely, one could also theorize that resident physicians, in an attempt to maximize time involved in patient care and their operative experience, are neglecting their administrative duties in order to satisfy their work-hour restrictions. Given the constraints of the 80-hour work week, residents could be expected to spend a lower percentage of their time on documentation to optimize other aspects of their training. By this logic, one would expect the rate of documented complications to decline. We prefer to base our argument on the available evidence. There is no data, to our knowledge, that supports an improvement in documentation habits of residents when duty hour restrictions are imposed. However, the increased number of resident handoffs following duty hour reform has been well documented (1). Multiple studies have demonstrated deficits in communication and information transfer leading to adverse patient outcomes (2-6). The available evidence clearly supports the assertion that transfers of patient care from one physician to another may be associated with an adverse event. Needless to say, our particular study methodology was not structured to allow us to look at this specific factor as it relates to the observed complications, so we are left to extrapolate from other available studies. Furthermore, we believe that it is highly unlikely that hospitals in the United States would rely exclusively on resident documentation to determine the final reporting of complications. Reimbursement is largely dependent upon accurate coding and documentation. At our institution, the coding for final discharge diagnoses and coding of co-morbidities and complications is completed by a group of individuals who specialize in this activity, and does not rely on a single resident’s documentation for accuracy. Perhaps secondary to differences in the reimbursement systems, the National Health Service in the United Kingdom may not be analogous to the U.S. healthcare system in the role of resident physicians and documentation. The American College of Surgeons has been explicit in stating that it is inappropriate for teaching hospitals to rely upon residents to perform tasks that are not directly related to either education or patient care (7). The issue of duty hours and patient care is both complex and important. We acknowledge the limitations of using an administrative database in our study. It is our hope that this preliminary study will lead to a critical review of this issue in the interest of patient care and encourage other investigators to find data from the U.S. healthcare system that confirm or refute our observations. References 1. Vidyarthi AR, Arora V, Schnipper JL, Wall SD, Wachter RM. Managing discontinuity in academic medical centers: strategies for a safe and effective resident sign-out. J Hosp Med. 2006;1:257-66. 2. Petersen LA, Brennan TA, O’Neil AC, Cook EF, Lee TH. Does housestaff discontinuity of care increase the risk for preventable adverse events? Ann Intern Med. 1994;121:866-72. 3. Arora V, Kao J, Lovinger D, Seiden SC, Meltzer D. Medication discrepancies in resident sign-outs and their potential to harm. J Gen Intern Med. 2007;22:1751-5. 4. Horwitz LI, Moin T, Krumholz HM, Wang L, Bradley EH. Consequences of inadequate sign-out for patient care. Arch Intern Med. 2008;168:1755-60. 5. Arora V, Johnson J, Lovinger D, Humphrey HJ, Meltzer DO. Communication failures in patient sign-out and suggestions for improvement: a critical incident analysis. Qual Saf Health Care. 2005;14:401-7. 6. Okie S. An elusive balance--residents' work hours and the continuity of care. N Engl J Med. 2007;356:2665-7. 7. American College of Surgeons. Statement on residency work hours. http://www.facs.org/fellows_info/statements/st-39.html. Accessed 2009 Oct 21. Resident Duty-Hour Reform Associated with Increased Morbidity Following Hip Fracture Resident Duty Hour Reform Associated with Increased Recording of Morbidity Following Hip Fracture 28 October 2009 Barry J. O'Neill, Registrar in Orthopaedic & Trauma Surgery Limerick Regional Hospitals, Ireland Send letter to journal: Re: Resident Duty Hour Reform Associated with Increased Recording of Morbidity Following Hip Fracture barryoneill1922{at}gmail.com Barry J. O'Neill To the Editor: As an orthopaedic trainee who was employed by the National Health Service in the United Kingdom when the European Working Time Directive was implemented, I can sympathize entirely with the motivational factors behind the recent study by Browne et al (1). The number of training hours lost to trainees in the 'interests' of trainee well-being, with (in the UK system at least) little or no flexibility and no allowance for trainee discretion, is frustrating in the extreme. So I have to applaud Browne et al. on their attempt to highlight some of the problems that the new restrictions have produced. I would however, raise a point that I think has been entirely overlooked in this particular study. The methodology of the study states that data were collected from the Nationwide Inpatient Sample (NIS), which is simply a summary of recorded discharge data. The authors use this system to highlight an increase in the incidence of pneumonia, hematoma, transfusion, and renal complications. They go on to say that, "consistent with our results, some recent studies have suggested that limiting work hours has had an adverse impact on patient outcome". The suggestion is that an increased number of hand-offs and an increase in the number of clinicians caring for each patient, have resulted in an increase in post-surgical complications such as pneumonia, hematoma, transfusion, and renal complications. In my experience, patients who develop these particular complications do so because of a variety of factors, and to suggest that an increase in the incidence of these complications is related to the new restricted working hours seems a bit simplistic. I would put it to Browne et al., that the incidence of these complications has in fact not changed significantly since the introduction of the resident duty hour reform, but that the resident duty hour reform has simply resulted in an increase in the documentation of complications on discharge summaries logged in the NIS. Put simply, residents now have more time and more energy at the end of a shift to complete their documentation fully and to record complications on discharge summaries that previously may not have been documented at all. The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family 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 author, or a member of his immediate family, is affiliated or associated. Reference 1. Browne JA, Cook C, Olson SA, Bolognesi MP. Resident duty-hour reform associated with increased morbidity following hip fracture. J Bone Joint Surg Am. 2009;91:2079-85.

Scientific Articles: Functional Outcomes for Unstable Distal Radial Fractures Treated with Open Reduction and Internal Fixation or Closed Reduction and Percutaneous Fixation. A Prospective Randomized Trial Rozental et al. (1 August 2009) [Abstract] [Full text] [PDF] Functional Outcomes for Unstable Distal Radial Fractures Treated with Open Reduction... Dr. Rozental responds to Mr. Holmes and colleagues 29 October 2009 Tamara D. Rozental, MD, Assistant Professor Harvard Medical School, Boston, MA Send letter to journal: Re: Dr. Rozental responds to Mr. Holmes and colleagues trozenta{at}bidmc.harvard.edu Tamara D. Rozental, MD We thank the authors for their thoughtful questions and remarks. We agree that post-operative immobilization likely plays an important role in explaining the lower DASH scores among patients treated with closed reduction and percutaneous pinning (and have included this as part of our title). Since post-operative immobilization is routinely employed following closed reduction and percutaneous pinning, we believe it is an important factor to consider when deciding on a treatment method for unstable fractures of the distal radius. Although our numbers were small, we were not able to detect any differences between age groups and believe that our study findings apply to young and elderly patients alike. Finally, the standard deviation in our return to work data is explained by the fact that several patients did not choose to take any time away from work during/after their treatment. We hope this helps to clarify the data and, once again, thank the authors for their comments. Functional Outcomes for Unstable Distal Radial Fractures Treated with Open Reduction... Group Homogeneity 29 October 2009 William JM Holmes, MBChB, MRCSEd, Doctor , A. Roche, M. Webb Send letter to journal: Re: Group Homogeneity willjmholmes{at}googlemail.com William JM Holmes, MBChB, MRCSEd, et al. To the Editor: We read the article by Rozental et al. (1) with great interest and welcome the authors' attempt to add more prospective studies to this highly controversial area of clinical practice (2). We also congratulate the authors on the regular and thorough follow up. We note from their introduction that they had a specific emphasis on "early functional recovery". One point we would like to make is that plaster immobilization is likely to affect the 6-week DASH score in the closed reduction and percutaneous fixation group when compared to those with ORIF and post-operative splinting. This makes it difficult to study early outcomes without inadvertently measuring the effect of plaster vs. splint, rather than the specific intervention desired. Furthermore, one of the difficulties encountered in all studies that attempt to compare interventions is that, in order to get sufficient numbers to provide statistical analysis, large age ranges exists for each group (19-77 years versus 24-79 years). This often makes it difficult to draw significant conclusions as age has a large bearing on patients perceived outcomes and functional ability - the requirements of a 17 year old are very different from those of a 79 year old. Furthermore, since occupation was not studied in the paper, it furthermore highlights the difficulty in grouping together such a heterogeneous population. Lastly, we admire the attempt look at return to work as this provides good patient-orientated outcome measure, but the statistics in this paper implied that return to work was 17+/-21 days versus 26+/-27 days. This would indicate that some patients returned to work 4 days prior to their injury, making the analysis difficult to interpret. Can the authors explain these numbers? 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. Rozental TD, Blazar PE, Franko OI, Chacko AT, Earp BE, Day CS. Functional outcomes for unstable distal radial fractures treated with open reduction and internal fixation or closed reduction and percutaneous fixation. A prospective randomized trial. J Bone Joint Surg Am. 2009;91:1837-46. 2. Henry MH. Distal radius fractures: current concepts. J Hand Surg Am. 2008;33:1215-27.

Scientific Articles: Effect of Innominate and Femoral Varus Derotation Osteotomy on Acetabular Development in Developmental Dysplasia of the Hip Spence et al. (1 November 2009) [Abstract] [Full text] [PDF] Effect of Innominate and Femoral Varus Derotation Osteotomy on Acetabular Development... Surgical Treatment of Developmental Dysplasia of the Hip - Our Experience 17 November 2009 Zoran S. Vukasinovic, Professor of Orthopaedics Institute for Orthopaedic Surgery "Banjica" Belgrade, Serbia, Zoran Bascarevic, Nemanja Slavkovic, Zorica Zivkovic Send letter to journal: Re: Surgical Treatment of Developmental Dysplasia of the Hip - Our Experience zvukasin{at}beotel.net Zoran S. Vukasinovic, et al. To the Editor: We read the paper by Spence et al. (1) with great interest. Living in Serbia, a country with a high incidence of developmental dysplasia of the hip (DDH) (2.4%), and working in the country's biggest orthopaedic hospital, we have acquired great experience in the surgical treatment of this disease. We started forty years ago, in a study conducted by Predrag Klisic (2). Our first treatment option was open hip reduction combined with a Chiari pelvic osteotomy and a femoral varus derotation osteotomy. Later on, the Chiari osteotomy was replaced by the Salter innominate osteotomy, and the femoral varus derotation osteotomy was replaced by femoral derotation with shortening. Currently, our treatment protocol is as follows (3,4): 1. Open reduction with a Salter innominate osteotomy and femoral derotation shortening osteotomy in all patients, aged 2 to 8 years with a hip dislocation. 2. In older children, 8-12 years of age, the combination of procedures is similar, but the Salter osteotomy is replaced by triple pelvic osteotomy. 3. In cases with femoral head deformities due to postreduction osteonecrosis (such as coxa plana) where postoperative spherical congruence cannot be achieved, a Chiari pelvic osteotomy is performed. 4. We do not perform surgical reduction of a dislocated hip in children over 12 years of age. 5. In less serious cases, hip dysplasia and subluxation, we perform an isolated pelvic osteotomy or a combination of pelvic and femoral osteotomies without opening the hip joint. This treatment option can be used even in adolescents. Using this protocol, acetabular development is very good in younger children and much better than it was previously when we performed isolated pelvic or femoral osteotomies. 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. Spence G, Hocking R, Wedge JH, Roposch A. Effect of innominate and femoral varus derotation osteotomy on acetabular development in developmental dysplasia of the hip. J Bone Joint Surg Am. 2009;91:2622-36. 2. Klisic P, Jankovic LJ, Basara V. [Open reduction with pelvic osteotomy and femoral shortening]. Acta Orthop Belg. 1990;56:269-74. French. 3. Gavrankapetanovic I, Vukasinovic Z. Surgical treatment of late developmental displacement of the hip. J Bone Joint Surg Br. 2005;87:1307. 4. Vukasinović Z, Vucetić C, Cobeljić G, Bascarević Z, Slavković N. [Developmental dislocation of the hip is still important problem--therapeutic guidelines]. Acta Chir Iugosl. 2006;53:17-9. Serbian.

Scientific Articles: Complications of Titanium and Stainless Steel Elastic Nail Fixation of Pediatric Femoral Fractures Wall et al. (1 June 2008) [Abstract] [Full text] [PDF] Complications of Titanium and Stainless Steel Elastic Nail Fixation of Pediatric... Dr. Wall and colleagues respond to Dr. Thakkar 3 November 2009 Eric J. Wall, MD, Director, Orthopaedic Surgery Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, Viral Jain, MD, Vagmin Vora, MD, Charles Mehlman, DO, MPH, Alvin H. Crawford, MD Send letter to journal: Re: Dr. Wall and colleagues respond to Dr. Thakkar eric.wall{at}cchmc.org Eric J. Wall, MD, et al. Thank you for your comments and the questions. Following are our answers to your questions: 1. How many patients had a mismatch in nail (TEN or SS elastic) diameter as seen in Fig 2-B (the nails are of a different diameter)? Except for the patient illustrated, none of the other 15 patients with malunion had any mismatching of the nails. Overall, less than 5% of our patients had mismatched nail placement, the patients were evenly distributed among the stainless steel and titanium groups (three and two respectively). 2. Did you use more than two nails in any single case? We have found that a child who weighs more than 40 kg or is over 11 years of age requires more than two nails; otherwise, malunion may occur. We have not used more than 2 nails in any of our patients in the study except the two cases of implant breakage. 3. In the case of breakage, was it breakage of both nails (all nails in a single case) or just one of the nails and was there malunion in that case? How much did that patient weigh? We had two cases of nail breakage. The nail breakage was seen in one patient with titanium nails with a resultant malunion. Only one nail was broken. This was treated by re-reduction and introduction of a third nail. The other patient had stainless steel nails, which did show breakage of one nail without malunion (according to our criteria) and was treated by insertion of a third nail. 4. You have mentioned that the stainless steel nails were custom made to order. Which type of steel material was used, 316L or 316LVM? What were the mechanical properties in terms of ultimate tensile strength and percentage of elongation upon tensile stress? Which company made the custom-made nails? Can you tell us whether the stainless steel nails were more flexible than the TEN nails supplied by Synthes (Synthes, Paoli, Pennsylvania)? Howmedica (Rutherford, NJ) was the supplier of the stainless steel nails. The company was integrated into Stryker in the year 1999. All of our stainless steel nails were 316LVM. Mechanical testing of these nails was not done for the present study. According to the surgeons’ clinical experience, the titanium nail feels more flexible than the stainless steel nail (1-3). References 1. Mahar AT, Lee SS, Lalonde FD, Impelluso T, Newton PO. Biomechanical comparison of stainless steel and titanium nails for fixation of simulated femoral fractures. J Pediatr Orthop. 2004;24:638-41. 2. Mani US, Sabatino CT, Sabharwal S, Svach DJ, Suslak A, Behrens FF. Biomechanical comparison of flexible stainless steel and titanium nails with external fixation using a femur fracture model. J Pediatr Orthop. 2006;26:182-7. 3. Arens S, Schlegel U, Printzen G, Ziegler WJ, Perren SM, Hansis M. Influence of materials for fixation implants on local infection. An experimental study of steel versus titanium DCP in rabbits. J Bone Joint Surg Br. 1996;78:647-51. Complications of Titanium and Stainless Steel Elastic Nail Fixation of Pediatric... Complication Comparison of Titanium and Stainless Steel Elastic Nails 3 November 2009 Navin N. Thakkar, Consulting Orthopedic Surgeon, Director Pragna Orthopedic Hospital, Ahmedabad, India Send letter to journal: Re: Complication Comparison of Titanium and Stainless Steel Elastic Nails naveenthakkar{at}gmail.com Navin N. Thakkar To the Editor: I read the article by Wall et al. (1) with great interest. It is a really interesting observation and we are also having the same experience in our practice. I would like to know from your data, which is not mentioned in your article: 1. How many patients had a mismatch in nail (TEN or SS elastic) diameter as seen in Fig 2-B (the nails are of a different diameter)? 2. Did you use more than two nails in any single case? We have found that a child who weighs more than 40 kg or is over 11 years of age requires more than two nails; otherwise, malunion may occur. 3. In the case of breakage, was it breakage of both nails (all nails in a single case) or just one of the nails and was there malunion in that case? How much did that patient weigh? 4. You have mentioned that the SS nails were custom made to order. Which type of steel material was used, 316L or 316LVM? What were the mechanical properties in terms of ultimate tensile strength and percentage of elongation upon tensile stress? Which company made the custom-made nails? Can you tell us whether the stainless steel nails were more flexible than the TEN nails supplied by Synthes (Synthes, Paoli, Pennsylvania)? The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family 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 author, or a member of his immediate family, is affiliated or associated. Reference 1. Wall EJ, Jain V, Vora V, Mehlman CT, Crawford AH. Complications of titanium and stainless steel elastic nail fixation of pediatric femoral fractures. J Bone Joint Surg Am. 2008;90:1305-13.

Scientific Articles: Extracellular Matrix Bioscaffolds for Orthopaedic Applications. A Comparative Histologic Study Valentin et al. (1 December 2006) [Abstract] [Full text] [PDF] Extracellular Matrix Bioscaffolds for Orthopaedic Applications. A Comparative Histologic... Dr. Badylak and Ms. Valentin respond to Dr. James and colleagues 18 November 2009 Stephen F. Badylak, DVM, PhD, MD, Professor, Department of Surgery University of Pittsburgh, McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, Jolene E. Valentin, BS Send letter to journal: Re: Dr. Badylak and Ms. Valentin respond to Dr. James and colleagues badylaks{at}upmc.edu Stephen F. Badylak, DVM, PhD, MD, et al. With regard to the letter by Dr. Kenneth James, Vice President of TEI Biosciences, we appreciate the opportunity to respond to the issues that were raised. First, our manuscript (1) clearly states that TissueMend is not chemically crosslinked (see discussion, page 2685, “...TissueMend does not include chemical crosslinking as a processing step...”). The article also states (Table 1) that processing methods are “proprietary”. The manuscript further describes the morphologic response to the implanted material as being a “typical response to a nonresorbable foreign material...”, but again, no mention is made of any chemical crosslinking. The host response to a nonresorbable material does not necessarily include the presence of multinucleate giant cells. One of the major points of the Valentin article is that each biologic scaffold material elicits a distinct morphologic response which is dictated by several factors including methods of processing. Second, all biologic scaffolds contain natural crosslinks which are susceptible to endogenous mechanisms of degradation. Chemical crosslinking agents such as carbodiimide and glutaraldehyde have typically been used to add strength to biologic scaffolds and/or modify surface antigens in the belief that this is necessary to prevent an adverse immune response. Non-chemical means of inducing crosslinks are also possible including thermal, photo-oxidative, and irradiation methods. Any method of crosslinking has the potential to slow the rate of in-vivo degradation and thus elicit a host response characterized by fibrosis and low-grade chronic inflammation. Since the methods of processing for TissueMend are proprietary, it is not possible to know the cause of the decreased degradation rate. The optimal use of biologic scaffold materials for not only orthopedic applications, but other applications as well, will depend upon an in depth understanding of the mechanisms by which such materials support, maintain, and restore healthy tissue. New data are being published on an almost weekly basis regarding the host immune response to these scaffold materials (2-4), the source and rate of cell recruitment (5, 6), the factors that affect cellular differentiation and organization (7, 8), and the factors that affect downstream remodeling and patient outcome (9). We agree completely with Dr. James that the microenvironment into which these scaffolds are placed is a critical determinant of remodeling (adoption versus adaptation) events. We also believe that an open dialogue regarding such factors is healthy and will lead to a more comprehensive understanding of the potential use of biologic scaffolds by the entire scientific and surgical community. References 1. Valentin JE, Badylak JS, McCabe GP, Badylak SF. Extracellular matrix bioscaffolds for orthopaedic applications. A comparative histologic study. J Bone Joint Surg Am. 2006;88:2673-86. 2. Daly K, Stewart-Akers A, Hara H, Ezzelarab M, Long C, Cordero K, Johnson S, Ayares D, Cooper D, Badylak SF. Effect of the alphaGal epitope on the response to small intestinal submucosa extracellular matrix in a nonhuman primate model. Tissue Eng Part A. 2009 Jun 29 [Epub ahead of print]. 3. Valentin JE, Stewart-Akers AM, Gilbert TW, Badylak SF. Macrophage participation in the degradation and remodeling of extracellular matrix scaffolds. Tissue Eng Part A. 2009;15:1687-94. 4. Badylak SF, Gilbert TW. Immune response to biologic scaffold materials. Semin Immunol. 2008;20:109-16. 5. Reing JE, Zhang L, Myers-Irvin J, Cordero KE, Freytes DO, Heber-Katz E, Bedelbaeva K, McIntosh D, Dewilde A, Braunhut SJ, Badylak SF. Degradation products of extracellular matrix affect cell migration and proliferation. Tissue Eng Part A. 2009;15:605-14. 6. Beattie AJ, Gilbert TW, Guyot JP, Yates AJ, Badylak SF. Chemoattraction of progenitor cells by remodeling extracellular matrix scaffolds. Tissue Eng Part A. 2009;15:1119-25. 7. Brown BN, Valentin JE, Stewart-Akers AM, McCabe GP, Badylak SF. Macrophage phenotype and remodeling outcomes in response to biologic scaffolds with and without a cellular component. Biomaterials. 2009;30:1482-91. 8. Gilbert TW, Stewart-Akers AM, Sydeski J, Nguyen TD, Badylak SF, Woo SL. Gene expression by fibroblasts seeded on small intestinal submucosa and subjected to cyclic stretching. Tissue Eng. 2007;13:1313-23. 9. Derwin, KA et al. Extracellular matrix scaffold devices for rotator cuff repair. J Shoulder Elbow Surg. In press. Extracellular Matrix Bioscaffolds for Orthopaedic Applications. A Comparative Histologic... TissueMend is not chemically crosslinked nor does it elicit a classic foreign body response 18 November 2009 Kenneth S. James, PhD, Vice President, Product Sciences TEI Biosciences, Kevin C. Cornwell, PhD; A. Gerson Greenburg, MD, PhD Send letter to journal: Re: TissueMend is not chemically crosslinked nor does it elicit a classic foreign body response kjames{at}teibio.com Kenneth S. James, PhD, et al. To the Editor: We would like to address statements related to the product TissueMend made in the paper by Valentin et al (1). Subsequent articles referencing this paper have not accurately reported the data presented (2,3), errata to which are now appearing (4). Please note that: • TissueMend is not artificially chemically crosslinked. While explicitly stated as such in the paper, the authors' grouping of TissueMend with the chemically crosslinked products tested in the paper’s abstract and discussion has led some to conclude otherwise. Chemical crosslinking is specifically avoided to preserve the native biopolymer chemistry to permit host adoption and adaptation of the implanted collagen structure and to avoid eliciting a chronic foreign body reaction and encapsulation response associated with chemically crosslinked implants. • TissueMend does not elicit a classic foreign body response. The data presented does not support the statements that the response to TissueMend is, “consistent with the typical response to a nonresorbable foreign material”, or, “associated with the presence of foreign-body giant cells, chronic inflammation, and/or the accumulation of dense, poorly organized fibrous tissue.” To the contrary, Table III explicitly indicates a statistically significant difference in foreign body giant cells to TissueMend (absent) to the chemically crosslinked products Permacol and CuffPatch (present). The absence of an acute or chronic inflammatory/foreign body reaction directed towards the TissueMend implant is similarly evident in Figures 5-A and 5-B. • The authors are correct when stating that, “…the proprietary methodology of making the final product [TissueMend] may be related to its relatively slow rate of degradation”. However, the authors incorrectly suggest that non-crosslinked collagen implants must necessarily be “degraded”. The histological results illustrate that the TissueMend collagen implant has been adopted and adapted by the host, filling with fibroblasts and supporting vasculature, to generate a new, long-lived tissue that effectively heals the small, surgically created partial- thickness muscle defect. This result and the absence of an inflammatory response directed towards the implant and generated tissue is consistent with reports on this same material in other soft tissue repair sites (5,6). However, it should be noted that subsequent adaptation of this implant is dependent on the site of implantation. For example, when specifically evaluated in a tendon repair model, TissueMend is similarly adopted but followed by the progressive adaptation of the implanted dermal collagen fibers into an aligned, oriented collagen fiber architecture comparable to tendon (7). We refer readers to an article by Cornwell et al. for a comprehensive review of the TissueMend technology (7). TissueMend Advanced Soft Tissue Repair Matrix is marketed by Stryker Orthopaedics (Mahwah, NJ) and was developed and is manufactured by TEI Biosciences (Boston, MA). In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in excess of $10,000 from TEI Biosciences. In addition, one or more of the authors or a member of his or her 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 (TEI Biosciences). References 1. Valentin JE, Badylak JS, McCabe GP, Badylak SF. Extracellular matrix bioscaffolds for orthopaedic applications. A comparative histologic study. J Bone Joint Surg Am. 2006;88:2673-86. 2. Chen J, Xu J, Wang A, Zheng M. Scaffolds for tendon and ligament repair: review of the efficacy of commercial products. Expert Rev Med Devices. 2009;6:61-73. 3. Aurora A, McCarron J, Iannotti JP and Derwin K. Commercially available extracellular matrix materials for rotator cuff repairs: State of the art and future trends. J Shoulder Elbow Surg 2007;16:171S-178S. 4. Aurora A, McCarron J, Iannotti JP, Derwin K. Commercially available extracellular matrix materials for rotator cuff repairs: state of the art and future trends. J Shoulder Elbow Surg. 2007;16(5 Suppl):S171-8. Erratum in: J Shoulder Elbow Surg. 2009 [In press, available online 2009 Aug 27]. 5. Zerris VA, James KS, Roberts JB, Bell E, Heilman CB. Repair of the dura mater with processed collagen devices. J Biomed Mater Res Part B Appl Biomater. 2007;83:580-8. 6. Cook JL, Fox DB, Kuroki K, Jayo M, DeDeyne PG. In vitro and in vivo comparison of five biomaterials used for orthopedic soft tissue augmentation. Am J Vet Res. 2008;69:148-56. 7. Cornwell KG, Landsman A, James KS. Extracellular matrix biomaterials for soft tissue repair. Clin Podiatr Med Surg. 2009;26:507-23.

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