Recent letters
Displaying 1-10 letters out of 835 published
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Concerns regarding the use of this technique in ankle arthrodesis
Submit responseSir,
I read this paper with interest. The authors propose to obtain autogenous bone graft for hindfoot arthrodesis surgery through the surgical field, avoiding the morbidity that may be associated with harvest from an anatomically distinct donor site.
This seems a perfectly reasonable assertion with regard to the technique described for retrograde intramedullary tibial harvest in tibiotalocalcaneal arthrodesis. In contrast, the technique described for antegrade intramedullary harvest in ankle arthrodesis appears to generate a number of the problems the authors propose to avoid:
i) an additional approach to the proximal tibia and cortical window is required
ii) graft harvest is not performed through the surgical field
iii) there is a risk of additional pain, morbidity and complications since there would typically be no requirement to violate the proximal tibia or intramedullary canal when undertaking an isolated ankle arthrodesis procedure
iv) although only one patient complained of anterior knee pain after undergoing this technique, only three patients underwent antegrade harvest - the incidence of anterior knee pain was therefore 33%.
I therefore believe that concerns exist that the use of the antegrade tibial intramedullary harvest technique in ankle arthodesis surgery is no more benign than alternative sources of autogenous bone graft. If this is indeed the case it is difficult to justify the additional costs.
M.A. Farndon,
Consultant Orthopaedic Surgeon,
Harrogate District Hospital,
Harrogate, Yorkshire, UK. -
Measurement techniques for acetabular version
Submit responseSir,
We read this paper with interest. As stated by the authors, computer tomography (CT) remains the gold standard in accurately determining acetabular component version. That said, in his classic article Murray1 pointed out that acetabular version can be defined in three ways: anatomical, surgical and radiographic, which are not equivalent. Consequently, acetabular version measured on CT axial slices using the transverse plane refers to anatomical anteversion whereas the measurement of version on plain x-rays refers to radiographic anteversion. Conversion between the two definitions is a trigonometric function of both the version and inclination as reported by Murray, and which is not linear.
Did the authors consider this in their analysis? Or was oblique reformatting of the CT slices done to allow measurement of radiographic anteversion? If not, it would appear that the authors compared radiographic version from plain x-rays with anatomical version from CT.
A.D. Speirs, MSc,
P.E. Beaulé, MD FRCSC,
Division of Orthopedic Surgery,
University of Ottawa,
Ottawa, ON, Canada.1. Murray DW. The definition and measurement of acetabular orientation. J Bone Joint Surg [Br] 1993;75-B:228-232.
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First or second generation ceramic
Submit responseSir,
I read with interest the retrieval analysis from the Rizzoli Institute of a series of ceramic-on-ceramic hip replacements implanted between 1984 and 1995. The purported aim of the study was to inform the readership of the performance of second-generation ceramic-on-ceramic bearings, and compare the findings with the literature for first-generation bearings. By the authors’ definition, second-generation ceramic bearings date from the introduction of Biolox forte (Ceram Tec, Plochingen, Germany) “at the end of the 1990s”. Not only does the period of implantation consign the devices examined to the first generation, but at least for the acetabular part of the bearing couple the ceramic was identified as standard Biolox. Whilst this report has added to the literature on first-generation ceramic bearing, it has not met its primary aim.
G. Scott,
Consultant Orthopaedic Surgeon,
Royal London Hospital,
London, UK. -
Reamer-irrigator-aspirator technique
Submit responseSir,
I read this article with interest but I have some concerns:
No validated outcome measure used.
No mention of the union rate following surgery.
It was mentioned that there were no fractures in the calcaneum, talus or tibia, then it was mentioned that there was a medial cortical defect above the plafond. I think this is classified as a fracture.I agree that RIA is a promising technique, but I find it difficult to draw such a conclusion from this paper.
S. Morgan,
SpR T&O,
Royal Manchester Children's Hospital,
Manchester, UK. -
In vitro phenotypic modulation of chondrocytes from knees of patients with osteochondritis dissecans
Submit responseSir,
We read this paper with interest and would like to make the following points:
1. Chondrocyte density may be quantified via direct cell counting using a haemocytometer1 or by the use of a fluorometric DNA assay employing a bisbenzimidazole dye.2 How accurate is measurement using a Coulter counter, as used in this study, against these alternative methods?
2. Was any quantitative analysis made of the biochemical composition of the chrondral tissue that in turn is critical in determining its inherent mechanical properties? In particular, the products of chondrocyte metabolism including glycosaminoglycans,3 matrix metalloproteins4-6 or tissue inhibitors of matrix metalloproteins.6 In addition, there are thought to be global patterns of matrix components existing in mammalian articular cartilage, with definite spatial and temporal patterns of glycosaminoglycans.7 Did the phenotypic modulation of the chondrocytes from patients with osteochondritis dissecans reflect this?
3. Human chondral tissue is known to exhibit quantitative biochemical variation depending on the load-bearing status.4,8 Does the data reported in this study suggest whether chrondrocytes from OCD lesions will react in a similar manner upon loading?
B.A. Rogers, MRCGP, DipSEM, FRCS(Orth),
Clinical Fellow,
A.D. Carrothers, DipIMC, RCSEd, FRCS(Orth),
Sunnybrook Health Sciences Center,
Toronto, Ontario, Canada.1. Ishii I, Mizuta H, Sei A, et al. Healing of full-thickness defects of the articular cartilage in rabbits using fibroblast growth factor-2 and a fibrin sealant. J Bone Joint Surg [Br] 2007;89-B:693-700.
2. Kim YJ, Sah RL, Doong JY, Grodzinsky AJ. Fluorometric assay of DNA in cartilage explants using Hoechst 33258. Anal Biochem 1988;174:168-76.
3. Smith RL, Gilkerson E, Kohatsu N, Merchant T, Schurman DJ. Quantitative microanalysis of synovial fluid and articular cartilage glycosaminoglycans. Anal Biochem 1980;103:191-200.
4. Blain EJ. Mechanical regulation of matrix metalloproteinases. Front Biosci 2007;12:507-27.
5. Mandal M, Mandal A, Das S, Chakraborti T, Sajal C. Clinical implications of matrix metalloproteinases. Mol Cell Biochem 2003;252:305-29.
6. Li H, Feng F, Bingham CO 3rd, Elisseeff JH. Matrix metalloproteinases and inhibitors in cartilage tissue engineering. J Tissue Eng Regen Med 2011 [Epub ahead of print].
7. Archer CW, Morrison EH, Bayliss MT, Ferguson MW. The development of articular cartilage: II. The spatial and temporal patterns of glycosaminoglycans and small leucine-rich proteoglycans. J Anat 1996;189(Pt 1):23-35.
8. Rogers BA, Murphy CL, Cannon SR, Briggs TW. Topographical variation in glycosaminoglycan content in human articular cartilage. J Bone Joint Surg [Br] 2006;88-B:1670-4. -
Heterotopic ossification in Dupuytren�s disease revisited
Submit responseSir,
We read this case report with interest and found it to be of relevance to our own work as it has shed light on some of our own in vitro research findings published earlier this year.1 In particular, we demonstrated the increased expression of Osteoblast-stimulating factor-1 (Osf-1) in Dupuytren’s disease (DD) tissue compared with carpal tunnel control. In addition, we also demonstrated that DD cells were able to differentiate into osteocytes.
Osf-1 (Pleiotrophin) which is expressed by osteoblasts has the ability to promote adhesion, migration, expansion, and differentiation of human osteoprogenitor cells, although some studies in mice have suggested that it is not required for bone formation while simultaneously showing that bone morphogenetic protein-2 (BMP-2) is essential for bone formation.2-4 We found that Osf-1 was expressed significantly higher in DD cord (p=0.001) and nodule (p=0.001) tissue compared with control transverse carpal ligament. Furthermore, there was a significantly higher expression of Osf-1 (p=0.01) in DD cord tissue compared with the nodule with a fold change of seven.1
In 1987, Andrew et al acknowledged the ability of fibroblasts in DD to undergo osseous metaplasia, which supports this case study’s findings which have characterised the bony lesion in DD as heterotopic ossification (HO).5 We have also shown that cells derived from DD biopsies contain a proportion of mesenchymal stem cells (MSCs) that were able to differentiate significantly (p<0.05) into osteocytes compared with fibroblasts derived from carpal tunnel tissue. Although this case study implicates heterotopic ossification (HO) as a cause for bony tissue, they have not checked immunohistologically the presence of increased calcium deposition or increased level of alkaline phosphatase that are considered the necessary prerequisite in order to ascertain the exact identity of HO.6
This case report also showed the presence of a highly dense collagen network in HO tissue corroborating with another study which has shown that higher concentrations of Osf-1 result in increased expression of collagen type 1.3 In osteoarthritis, Osf-1 is especially expressed in early stages, and its concentrations in the synovial fluid could potentially serve as a marker for the progress of the disease.7 Osf-1 could also potentially be used in a similar manner in DD in conjunction with detection of other relevant factors like BMPs.
Our own recently published paper gives further credence and supports the findings of HO in DD. Nevertheless, future studies are required to look for correlations between Osf-1 production and an increase in calcium deposition with an enhanced expression of BMPs.
C.J. Manning, Foundation Doctor,
Stepping Hill Hospital and Plastic and Reconstructive Surgery Research,
S.A. Iqbal,
A. Bayat,
Plastic and Reconstructive Surgery Research,
School of Translational Medicine, MIB,
University of Manchester,
Manchester, UK.1. Iqbal SA, Manning C, Syed F, et al. Identification of Mesenchymal Stem Cells in Perinodular Fat and Skin in Dupuytren's Disease: A Potential Source of Myofibroblasts with Implications for Pathogenesis and Therapy. Stem Cells Dev 2011 [Epub ahead of print].
2. Imai S, Kaksonen M, Raulo E, et al. Osteoblast recruitment and bone formation enhanced by cell matrix-associated heparin-binding growth-associated molecule (HB-GAM). J Cell Biol 1998;143:1113-28.
3. Tare RS, Oreffo RO, Clarke NM, Roach HI. Pleiotrophin/Osteoblast-stimulating factor 1: dissecting its diverse functions in bone formation. J Bone Miner Res 2002;17:2009-20.
4. Yang X, Tare RS, Partridge KA, et al. Induction of human osteoprogenitor chemotaxis, proliferation, differentiation, and bone formation by osteoblast stimulating factor-1/pleiotrophin: osteoconductive biomimetic scaffolds for tissue engineering. J Bone Miner Res 2003;18:47-57.
5. Andrew JG. Calcification in Dupuytren's disease: a report of two cases. J Hand Surg Br 1987;12:277-8.
6. Koyama N, Okubo Y, Nakao K, Osawa K, Bessho K. Experimental study of osteoinduction using a new material as a carrier for bone morphogenetic protein-2. Br J Oral Maxillofac Surg 2011;49:314-8.
7. Sanchez C, Deberg MA, Piccardi N, et al. Subchondral bone osteoblasts induce phenotypic changes in human osteoarthritic chondrocytes. Osteoarthritis Cartilage 2005;13:988-97. -
Warfarin management - questions and concerns
Submit responseSir,
We read this paper with interest. The area of perioperative warfarin management is one that is fraught with difficulties and a lack of clear guidance. There are a few points which I would like to raise regarding this study.
First, the conclusion arrived at - namely that continuing warfarin therapy is a safe alternative to bridging heparin therapy - is misleading as it implies that the two different methods were directly compared, which is not the case. The group continuing on warfarin was compared with a control group which commenced on warfarin therapy on the day of surgery but without any low-molecular-weight heparin being used. Therefore, the authors' results can only be used to compare outcomes in patients who were already on warfarin with those of patients who were commenced on warfarin.
The two groups were not directly comparable if the adverse effects recorded included venous thromboembolism. As the authors mention in their discussion, patients who are commenced on warfarin experience a rebound hypercoagulable state in the first 36 hours. It is therefore not possible to compare patients with existing therapeutic international normalised ratios (INR) with a group who will not become therapeutic for roughly 36 hours post-operatively.
This also raises an ethical question of the appropriateness of commencing a group of patients on a medication that has potentially serious side-effects (and primary effects) without any medical indication. It would have been interesting to note when the two DVT and two pulmonary emboli occurred in this warfarin-initiated group; was it within the first 36 hours when arthroplasty patients are known to be at highest risk of thromboembolism now compounded by their hypercoagulable state?
Finally, it is my experience that those patients who require warfarin for mechanical heart valves are more accurately and rapidly controlled with unfractionated heparin and it is these patients who need very tight anticoagulation control. Furthermore, if, according to the quoted papers, patients suffer from a change in INR ranging from 1.8 to 2.2, is it at all safe to be operating on these patients without some bridging anticoagulation? The four patients in this study with INRs less than 1.9 on the day of surgery are not a therapeutic range and therefore surely cannot be used as a comparison.
G.V. Morris,
Specialty Registrar, Trauma & Orthopaedics,
J. Giza,
M.J. Gandhi,
Russells Hall Hospital,
Dudley, UK. -
PROMS: clinical relevence
Submit responseSir,
I read this paper with interest. The authors offer detailed information on the value of patient-reported outcome measures (PROMS) gained from a very large prospective study. This was also the topic of a PhD thesis by the senior author. A statement made in the article demands explanation. One of their conclusions, "We cannot tell from these results whether surgery is being done at the right time or on the right patients." seems to cast doubt on the value of the report. Is this correct?
B.M. Wroblewski,
Charnley Research Institute,
Wrightington Hospital,
Wigan, UK. -
Early high failure of LCS patellofemoral arthroplasty: another series from the UK
Submit responseSir,
This article, and further opinions along with the author’s reply were keenly followed by us with interest. Our interest in this article is based on the initial experience we had with the LCS patellofemoral arthroplasty implant which was published in the Knee journal in October 2010.1
The short-term results of a cohort of 21 patients (with 24 LCS patellofemoral replacements) were presented at the AAOS 2011 meeting.2 In our series, the rate of revision of mobile bearing patellofemoral replacement was 33% at two-year follow-up and none of the patients was revised for infection or progressive tibiofemoral degeneration. The mechanical complications and appearances at revision suggest that the mobile bearing fails in flexion due to high patellofemoral joint reaction forces in these patients as they are often young and in active employment. An all-polyethylene LCS fixed bearing with lesser constraint on the patellar polyethylene could eliminate these early complications leading to comparable results similar to other models.3 We are in agreement with Professor Merchant’s argument that technique and patient selection are critical, however, we feel that there is similarity in the results presented here by Charalambos et al and in our series. Restriction of activity (avoid weight bearing with the knee in more than 90° of flexion) is generally counselled to patients before the surgery but may not be the only factor in preventing any early failures.
Moreover, DePuy has discontinued this implant and brought in the Sigma partial knee system4 with a dome patellar implant. The purpose of this letter is to make the orthopaedic community aware of smaller but similar series of results with mobile bearing low contact stress patellofemoral arthroplasty. If a surgical technique or use of an implant is very unforgiving with a narrow patient selection criteria the surgical implant may not have wider acceptance as results are not reproducible.
B.R.B. Arumilli,
Specialty Doctor in Orthopaedics,
Department of Trauma & Orthopaedics,
Manchester Royal Infirmary,
Manchester, UK.1. Arumilli BR, Ng AB, Ellis DJ, Hirst P. Unusual mechanical complications of unicompartmental low contact stress mobile bearing patellofemoral arthroplasty: a cause for concern? Knee 2010;17:362-4.
2. Arumilli BRB, Hirst P, Ng A, Ellis DJ. Short Term Results of Low Contact Stress Mobile Bearing Unicompartmental Patellofemoral Arthroplasty. AAOS 2011 Annual Meeting. http://www.aaos.org/education/anmeet/programs/FinalProgram.pdf Poster P117:219.
3. Odumenya M, Costa ML, Parsons N, et al. The Avon patellofemoral joint replacement: five-year results from an independent centre. J Bone Joint Surg [Br] 2010;92-B:56-60.
4. DePuy: Sigma® High Performance Partial Knee System. http://www.depuy.com/healthcare-professionals/product-details/sigma -high-performance-partial-knee-system. -
Total hip replacement for high dislocated hips without femoral shortening osteotomy: questions
Submit responseSir,
We thank Dr Zhang et al for this report of 74 THRs performed on patients with high hip dislocations without osteotomy. This is a very interesting paper challenging the necessity of a subtrochanteric osteotomy, which delays post-operative rehabilitation, interferes with the primary stability of the femoral component and has been found prone to healing problems. We read it with interest and have several questions regarding this paper.
We feel that the technique for soft tissue release the authors used in order to achieve reduction without shortening was not defined clearly enough in the report. This is our main interest because in some of our high hip dislocation cases, we have found the hamstrings to be so tight that they prevent prosthetic reduction even in the presence of a shortening osteotomy. Further shortening had to be performed and on several occasions we have had to isolate the ischial tuberosity and release the hamstring muscles from their origin. In other patients, tightness of the flexor group along with the iliotibial tract presented a similar difficulty, not only for the reduction of the hip but also acute patellar dislocation which we have observed in two patients when the limb was forced to elongate. This might be because valgus knees and hypoplastic lateral femoral condyles are relatively common in this group of patients. We are very curious about the authors’ techniques for dealing with similar problems.
The position of the extremity after forced reduction is another interesting point. The authors mention keeping the patients’ hips and knees in flexion in order to reduce stretch on the sciatic nerve. However, the report details several femoral nerve palsies and no sciatic nerve palsies. We have a series of 84 THRs performed at our institution with shortening osteotomy where we have observed no sciatic nerve palsy but two transient femoral nerve palsies. We concluded that contrary to the common belief, the femoral nerve is at more risk during this procedure and keeping the knee extended might be a better precaution for the palsy of this particular nerve.
In our aforementioned series, we have also observed three cases where medial acetabular wall fractures with pelvic protrusio occurred at the first follow-up visit (six weeks postoperatively). All three patients were older than 50 years. We thought that the limited bone stock around the acetabulum and deficient bone quality were the reasons for this particular complication and that the periacetabular bone was not able to bear even sub-physiological loading (patients were on crutches with non-weight bearing ambulation). Another observation during our series was that in a considerable number of cases the femoral anteversion was found to be so high that without rotational correction a cementless femoral component could not possibly be inserted in the correct orientation. In our opinion, this is another reason to perform subthrochanteric osteotomy. We would like to have the authors’ comments regarding our concerns.
Z.D. Olgun,
Orthopaedic Surgeon,
B. Atilla,
Dortyol State Hospital,
Hatay, Turkey.
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