Musculoskeletal Specialists Research Articles

Camptocormia: don’t forget muscle disease in the movement disorder clinic

The cause of isolated camptocormia or ‘bent spine syndrome’ is various and often difficult to establish [1]. Patients may present to neurologists or musculoskeletal specialists but many remain without diagnosis. We recently reported a patient with camptocormia due to facioscapulohumeral dystrophy (FSHD) that had been initially diagnosed as idiopathic axial dystonia in a movement disorder clinic [2]. A second case of muscle disease masquerading as dystonia has now come to light. In this report we provide helpful diagnostic pointers that may help neurologists to pick up these cases and avoid inappropriate treatment. The patient was of non-consanguineous Ashkenazi Jewish descent. She first presented to a neurologist at the age of 66 with a 9-year history of involuntary bending of her spine when walking. Any attempt to overcome the forward flexion led to shortness of breath and increased difficulty walking. Pushing a shopping trolley caused significant improvement in her posture. She also complained of a tight band sensation around her upper abdomen. She had a past history of rheumatic fever at 8 years of age (no history of chorea) with subsequent mitral valve disease necessitating replacement with a prosthetic metal valve at the age of 46. Six years before presentation she had an episode of presumed polymyalgia rheumatica (based on symptoms of pain and stiffness around her neck, shoulders and upper arms and an elevated ESR—between 40–50 mm/h), which settled with a short course of steroids. She also had an 8-year history of deafness in the left ear. Her medications included warfarin, digoxin, bisoprolol, losartan, furosemide, spironolactone and quinine sulphate. She had never been exposed to dopamine blocking drugs. Her mother had a similar posture in her later years. On examination she had spontaneous flexion of the trunk, which worsened the further she walked. Using a rollator or placing her hands on her thighs enabled her to straighten her trunk (video). There was no fixed deformity when lying supine, and spinal imaging revealed multi-level degenerative changes but no spinal cord compression or radiculopathy. She was diagnosed with camptocormia due to idiopathic axial dystonia. DYT1 testing was negative. Focal myopathy was considered a possible cause but electromyography was felt to be contraindicated due to her treatment with warfarin. L-dopa (150 mg/day), anticholinergic drugs (trihexyphenidyl 6 mg/day and tetrabenazine 12.5 mg/day) Electronic supplementary material The online version of this article (doi:10.1007/s00415-012-6448-z) contains supplementary material, which is available to authorized users.

MRI Appearance of the Proximal Hamstring Tendons in Patients With and Without Symptomatic Proximal Hamstring Tendinopathy

The purpose of our study was to determine if six MRI findings of the proximal hamstrings differ in frequency in hamstrings with and without symptoms of tendinopathy. We reviewed the MRI examinations of 118 consecutive patients who had undergone pelvis MRI and evaluation by a musculoskeletal clinical specialist. The proximal hamstrings were evaluated at four consecutive axial locations for tendon size, internal T1 and T2 signal, peritendinous T2 signal, and ischial tuberosity edema. Statistical analysis was performed to determine the association of the MRI findings with symptomatic hamstring tendinopathy. Twenty-one patients had a clinical diagnosis of unilateral proximal hamstring tendinopathy. The mean width or anteroposterior size was significantly larger in symptomatic hamstrings at all three proximal levels (p = 0.002-0.040). More than 90% of hamstring tendons had increased internal T1 or T2 signal that was not associated with hamstring symptoms. Both hamstrings with and without symptoms of tendinopathy had peritendinous T2 signal, but this was significantly more common in hamstrings with tendinopathy symptoms at the three most distal levels (p = 0.001-0.041). Ischial tuberosity edema and a feathery appearance of the peritendinous T2 signal distally were significantly more common in symptomatic hamstrings (p = 0.004 and 0.001, respectively). Increased T1 and T2 signal is commonly seen within the proximal hamstrings but is not associated with symptoms of hamstring tendinopathy. Increased tendon size, peritendinous T2 signal with a distal feathery appearance, and ischial tuberosity edema are significantly associated with symptomatic hamstring tendinopathy but can be seen in asymptomatic individuals.

Physical Therapist Practice and the Role of Diagnostic Imaging

For healthcare providers involved in the management of patients with musculoskeletal disorders, the ability to order diagnostic imaging is a beneficial adjunct to screening for medical referral and differential diagnosis. A trial of conservative treatment, such as physical therapy, is often recommended prior to the use of imaging in many treatment guidelines for the management of musculoskeletal conditions. In the United States, physical therapists are becoming more autonomous and can practice some degree of direct access in 48 states and Washington, DC. Referral for imaging privileges could increase the effectiveness and efficiency of healthcare delivery, particularly in combination with direct access management. This clinical commentary proposes that, given the American Physical Therapy Association's goal to have physical therapists as primary care musculoskeletal specialists of choice, it would be beneficial for physical therapists to have imaging privileges in their practice. The purpose of this commentary is 3-fold: (1) to make a case for the use of imaging privileges by physical therapists, using a historical perspective; (2) to discuss the barriers preventing physical therapists from having this privilege; and (3) to offer suggestions on strategies and guidelines to facilitate the appropriate inclusion of referral for imaging privileges in physical therapist practice. J Orthop Sports Phys Ther 2011;41(11):829-837. doi:10.2519/jospt.2011.3556.

Diagnostic accuracy of magnetic resonance imaging and magnetic resonance arthrography of the hip is dependent on specialist training of the radiologist

Significant differences between magnetic resonance imaging reports and intraoperative findings at the time of hip arthroscopy were documented in our practice. We sought to examine the accuracy of radiological reporting of hip pathology based on the training level of the reporting radiologist. A retrospective review of hip arthroscopies carried out between July 2008 and June 2009 identified 61 cases where original MRI scans had been reported by general community radiologists. These scans were then reviewed by musculoskeletal specialist radiologists who were blinded to both the original report and the surgical findings. Accuracy of both subsets of radiologists was compared to arthroscopic findings with regard to labral, acetabular, femoral and impingement lesions. Musculoskeletal radiologists performed better than community radiologists in terms of overall accuracy. Accuracy rates for MSK radiologists were 85, 79, 59, and 82% for labral, acetabular chondrosis, and femoral chondrosis and impingement lesions, respectively. Whereas accuracy rates for community radiologists were 70, 28, 52, and 59% (p values = 0.08, <0.001, 0.59, <0.001). Accuracy was significantly improved for both groups of radiologists when MR arthrograms were reviewed rather than conventional MRIs. This study establishes the relationship between accuracy of reporting and the training level of the performing radiologists.

Ensuring quality of care through implementation of a competency‐based musculoskeletal education framework

Introduction As the Bone and Joint Decade 2000–2010 draws to a close, it is timely to review its impact on musculoskeletal medical education, which was clearly identified by the World Health Organization as a key factor contributing to less than optimal musculoskeletal care (1). The increasing burden of musculoskeletal disorders (including chronic bone and arthritic conditions) and the uncertain quality of care provided (2,3) has meant that there is a growing imperative to ensure that optimal, evidence-based, and cost-effective treatment is being provided to people with musculoskeletal disorders by medical practitioners (4). In 2004, the Bone and Joint Decade established the International Education Task Force and Undergraduate Curriculum Development Group to develop strategies to address the issue of insufficient and/or inadequate medical education, particularly in the areas of basic and clinical science (5,6). They released global core recommendations for a musculoskeletal undergraduate medical curriculum, which were designed to enable the development of a locally applicable musculoskeletal curriculum that was able to meet national guidelines and be reflective of local needs, priorities, and opportunities (5). Despite the release of the global core recommendations for a musculoskeletal undergraduate medical curriculum, in 2007 Woolfe and Akesson identified that the poor quality of medical education and a lack of coordination between the different disciplines and professional specialties working in musculoskeletal health care have meant that people do not receive the best practice treatment (6). Furthermore, in 2007 Day et al demonstrated significant deficiencies in the knowledge of chronic arthritic conditions in graduating medical students (2). Deficiencies in undergraduate education in musculoskeletal science have also been identified by medical students and graduates in studies conducted in a number of countries (2,7–10), and there is an obvious requirement for clinically relevant, evidence-based curriculum design that integrates traditional scientific and clinical disciplines. The Australian Musculoskeletal Education Collaboration (AMSEC) project began in Australia in 2005, with the aim of developing nationally agreed musculoskeletal core competencies (based on the Bone and Joint Decade curriculum recommendations) for implementation in all Australian medical schools. Initiated by the Australian Orthopaedic Association and funded by the Australian government, this project has succeeded in bringing together all key musculoskeletal specialist and representative organizations in a national, multidisciplinary education collaboration (including orthopedics, rheumatology, general practice, rehabilitation medicine, sports medicine, endocrinology, neurology, geriatrics, radiology, pediatrics, nursing, and interested allied health professions). While the Bone and Joint Decade recommendations formed the base from which the Australian competencies were developed, it was also vital that specific Australian standards and requirements were considered. The AMSEC competencies were therefore also related directly to the Australian Medical Council standards and principles and The National Patient Safety Framework (11,12). The purpose of this article is to outline the relevance of a competency-based approach to musculoskeletal education and to describe the development of theAMSECmusculoskeletal core competencies. Furthermore, we demonstrate the significance of the AMSEC competencies and the competency education process for optimal education in musculoskeletal medicine relative to chronic rheumatic disease.

Frozen shoulder: a consensus definition

Frozen shoulder (FS) is a common diagnosis treated by orthopaedic surgeons and other physicians caring for musculoskeletal problems. However, there is no standard definition and classification for this common condition. We asked 211 clinician members of the American Shoulder and Elbow Surgeons to review our proposed definition of FS and its classification into primary and secondary types. Secondary FS was further divided into intrinsic, extrinsic, and systemic types. The survey required responses to 5specific questions via an analog scale (1, strongly disagree; 5, strongly agree). Agreement was defined as a 4 or 5 on the analog scale. We received 190 responses (90%). Eighty-two percent agreed with the proposed definition of FS. Eighty-five percent agreed that FS should be divided into primary and secondary types. Sixty-six percent agreed with subdivision of secondary FS into intrinsic, extrinsic, and systemic types. Eighty-four percent agreed that there was a clinical entity of primary or idiopathic FS. Eighty-five percent agreed that obtaining a consensus definition and classification of FS was a worthwhile endeavor. Significant benefits can be gained from the development of a standard definition and classification of FS, achieved through a consensus of shoulder specialists, that provides a strong foundation for potential acceptance by all musculoskeletal specialists who treat this condition.

Effects of Statins on Skeletal Muscle: A Perspective for Physical Therapists

Hyperlipidemia, also known as high blood cholesterol, is a cardiovascular health risk that affects more than one third of adults in the United States. Statins are commonly prescribed and successful lipid-lowering medications that reduce the risks associated with cardiovascular disease. The side effects most commonly associated with statin use involve muscle cramping, soreness, fatigue, weakness, and, in rare cases, rapid muscle breakdown that can lead to death. Often, these side effects can become apparent during or after strenuous bouts of exercise. Although the mechanisms by which statins affect muscle performance are not entirely understood, recent research has identified some common causative factors. As musculoskeletal and exercise specialists, physical therapists have a unique opportunity to identify adverse effects related to statin use. The purposes of this perspective article are: (1) to review the metabolism and mechanisms of actions of statins, (2) to discuss the effects of statins on skeletal muscle function, (3) to detail the clinical presentation of statin-induced myopathies, (4) to outline the testing used to diagnose statin-induced myopathies, and (5) to introduce a role for the physical therapist for the screening and detection of suspected statin-induced skeletal muscle myopathy.

WEB ALERT

Biomet: www.biomet.com/biologics/whyGPS.cfm Description: Biomet is a multibillion dollar company that designs and manufactures products used primarily by musculoskeletal medical specialists in both surgical and nonsurgical therapy. The products sold range from surgical tools and implants to biologics such as systems used for platelet rich plasma (PRP) therapy. The Web site also provides clear directions to professionals regarding training for use of their products. It is a well designed, easy-to-navigate, and visually appealing Web site. Its product descriptions are succinct and useful with easy to understand graphics. Cost: Free. American Osteopathic Association: www.osteopathic.org Description: The American Osteopathic Association is a membership organization that represents thousands of osteopathic physicians around the country and serves as the primary certifying body for osteopathic doctors, medical schools, and health care facilities. The Web site provides the history and structure of the organization as well as a series of useful medical links for professionals and patients. It also provides a nice description of the differences in allopathic and osteopathic medicine and includes a Spanish version of the document. Overall, the Web site is well designed, intuitive, and provides useful information. Cost: Free. The Natural Standard: www.naturalstandard.com Description: Natural Standard is an international research collaboration that aggregates and synthesizes data on complementary and alternative therapies. Recommendations are made by a panel of physicians, research scientists, naturopathic doctors, pharmacists, and nurses. The group attempts to use evidence-based, consensus-based, and peer-reviewed material to help guide health care providers in making more informed decisions regarding use of alternative therapies. The site offers a tremendous amount of quality information and is very easy to use. Cost: Negotiated by contacting the company. Clin-eguide: www.clineguide.com/index.aspx Description: Clin-eguide is an online clinical decision support tool designed for physicians, nurses, pharmacists, and large health care facilities. The site uses a variety of sources and products in combination to allow for quick research into a clinical question. The results of clinical searches are also graded by quality. This is a very powerful tool for clinicians involved in medical decision making or for research. The program is very easy to navigate and simple to use. The Web site for the product is somewhat oversimplified and redundant but gives good information about what the tool can offer clinicians. Cost: Negotiated by contacting the company. Steadman Philippon Research Institute: www.shsmf.org Description: The Steadman Philippon Research Institute (formerly the Steadman Hawkins Research Foundation) is an independent charitable foundation that focuses its studies on causes, prevention, and treatment of orthopedic disorders. It was founded in 1988 by an orthopedist named Dr. Richard Steadman. Since that time, it has grown into a very large clinical and basic science research center located in Vail, CO. Its Web site discusses ongoing and past research and gives detailed results of its projects. It also discusses the history of the program as well as the personnel who have been involved through the years. The structure of the site is well designed and easy to navigate, although there are a few long scrolling sections that are somewhat cumbersome to read. Overall it is a nice site for those interested in orthopedic research. Cost: Free.

El dolor lumbar en el año 2009

Almost everyone will experience low back pain at some point in their lives and recognizes the very high frequency of lower back pain and its significant social and occupational impact. Low back pain is one of the most common conditions in general practice consultations and musculoskeletal specialists (orthopedists, rheumatologists and rehabilitation). It has characteristics of an epidemic in most developed societies, and has been dubbed by some as "disease of the century". Between doctor visits, after cold symptoms followed immediately back pain. The job retention of workers suffering from back and preventing chronic back pain are growing concerns of those responsible for public health because of the high costs this creates health problems in the community. To address this major public health problem, the scientific literature, relying mainly on studies Scandinavian and North American, proposes and attaches great importance to early and appropriate medical intervention in low back pain in the acute phase.

Survey of US chiropractors' perceptions about their clinical role as specialist or generalist

Objective The purpose of this study was to provide new information that describes chiropractors' professional identity relative to their perceived clinical role as specialist or generalist. Methods A pragmatic, descriptive, cross-sectional survey was performed of randomly sampled state-board licensed chiropractors in the United States during the period 2002–2003 to assess the chiropractors' perceptions of how their chiropractic patients see them, and how they see themselves, as specialist or generalist. For this exploratory study, we anchored the terms “back pain specialist,” “musculoskeletal specialist,” and “primary care generalist” to brief generic reference definitions in our survey instrument. Results Of our 2598 valid survey contacts, 1343 chiropractors returned their surveys either partially or fully completed, and a total of 720 chiropractor surveys were used in this study. Most of these chiropractors perceived that their new patients viewed them as “back pain specialists.” Chiropractors believed that their established patients (80%), more so than their new patients (58%), were likely to view them as a primary care generalist. Chiropractors described themselves as both specialist and generalist, and they expressed a greater capability to diagnose, rather than to treat, health disorders that were not musculoskeletal. Conclusion Chiropractic physician perceptions as reported in this study suggest that the nature of certain chiropractor-patient relationships may evolve profoundly over time, particularly as patients transition from new to established patients within the chiropractic practice. Understanding the complex nature of chiropractic health care provision may carry implications for advancing evidence-based chiropractic practice and clinical training, enhancing successful and comprehensive management of the complex health concerns of chiropractic patients, fostering beneficial sustained partnerships between chiropractors and their patients, and improving overall delivery of optimal integrative health care.

The Physical Therapist as a Musculoskeletal Specialist in the Emergency Department

Because patients with musculoskeletal injuries commonly seek intervention in the emergency department (ED), it has been proposed that practitioners with expertise in musculoskeletal practice can be of benefit in this setting. This clinical commentary describes the rationale for utilizing physical therapists as musculoskeletal specialists in the ED. Evidence indicates that physical therapists have the knowledge and skills to provide such expertise. Literature describing ED practice suggests that the management of patients with musculoskeletal conditions would be improved through the consistent integration of evaluation and treatment principles associated with physical therapy practice. Furthermore, early access to physical therapy, as can be provided in the ED setting, has the potential to positively influence patient recovery. Based on prior research and recent evolution of practice, further consideration of physical therapists as consultants in the ED is warranted, and, therefore, additional dialogue on the subject should be encouraged.

Validation of the GALS musculoskeletal screening exam for use in primary care: a pilot study

BackgroundAs the proportion of the Canadian population ≥65 grows, so too does the prevalence of musculoskeletal (MSK) conditions. Approximately 20% of visits to family physicians occur as a result of MSK complaints. The GALS (Gait, Arms, Legs, and Spine) screening examination was developed to assist in the detection of MSK abnormalities. Although MSK exams are primarily performed by rheumatologists or other MSK specialists, expanding their use in primary health care may improve the detection of MSK conditions allowing for earlier treatment. The primary goal of this study was to evaluate the use of the GALS locomotor screen in primary care by comparing the results of assessments of family physicians with those of rheumatologists. The secondary goal was to examine the incidence of MSK disorders and assess the frequency with which new diagnoses not previously documented in patients' charts were identified.MethodsPatients ≥65 years old recruited from an academic family health centre were examined by a rheumatologist and a family physician who recorded the appearance of each participant's gait and the appearance and movement of the arms, legs and spine by deeming them normal or abnormal. GALS scores were compared between physicians with the proportion of observed (Pobs), positive (Ppos) and negative (Pneg) agreement being the primary outcomes. Kappa statistics were also calculated. Descriptive statistics were used to describe the number of "new" diagnoses by comparing rheumatologists' findings with each patient's family practice chart.ResultsA total of 99 patients consented to participate (92 with previously diagnosed MSK conditions). Results showed reasonable agreement between family physicians and rheumatologists; Pobs = 0.698, Ppos = 0.614 and Pneg = 0.752. The coefficient of agreement (estimated Kappa) was 0.3675 for the composite GALS score. For individual components of the GALS exam, the highest agreement between family physicians and rheumatologists was in the assessment of gait and arm movement.ConclusionPreviously reported increases in undiagnosed signs and symptoms of musculoskeletal conditions have highlighted the need for a simple yet sensitive screening exam for the identification of musculoskeletal abnormalities. Results of this study suggest that family physicians can efficiently use the GALS examination in the assessment of populations with a high proportion of musculoskeletal issues.

Human bone marrow mesenchymal stem cells in vivo

Great confusion still exists amongst cell biologists, musculoskeletal and other specialists interested in regenerative medicine regarding the in vivo identity of human bone marrow (BM) mesenchymal stem cells (MSCs). Contrary to views held in some quarters, methods for the robust identification and purification of BM MSCs are now well established. Human BM MSCs represent a phenotypically homogeneous cell population that share an identical phenotype with marrow adventitial reticular cells (ARCs), which are stromal cells similar in nature to pericytes. When an extensive panel of markers is used to characterize BM MSCs, it appears that the diverse MSC markers described in different laboratories are expressed on the same cell population. Rare cell phenotypical analysis and in vitro colony forming unit-fibroblast (CFU-F) assays produce no compelling evidence that BM MSCs circulate in healthy man. Furthermore, although investigators speak of a number of specific MSC markers, a true marker of MSC 'stemness' and multipotentiality has not yet been defined since culture-expanded MSCs may lose some of these markers, but remain multipotential. This knowledge provides a platform for understanding MSCs in vivo leading to novel approaches for therapy development, including in situ tissue engineering.

The Relationship Between Local Availability and First-time Use of Specialists in an Arthritis Population

To determine what health area characteristics, in particular local availability of specialists, were associated with the age-sex adjusted ambulatory utilization rate of musculoskeletal (MSK) specialists (i.e., rheumatologists, orthopaedic surgeons and general internists) in an arthritis and rheumatism (A&R) cohort. The cohort was composed of respondents aged 15+ from the 1996/97 Ontario Health Survey who self-reported A&R and/or had a primary care encounter for A&R during the two years preceding the survey, as determined by their billings in the Ontario Health Insurance Plan. Respondents with prior exposure to MSK specialists were excluded. The outcome of an encounter with a MSK specialist for A&R was determined during the three-year period after the survey. The A&R cohort was composed of 5,052 respondents, of whom 11% had an A&R encounter with a MSK specialist in the three-year post-survey period. There was area variation in the age-sex adjusted ambulatory utilization rate of MSK specialists in the A&R cohort. The backwards stepping linear regression to examine predictors for seeing MSK specialists found a positive association with local availability of rheumatologists, a negative association with the proportion of high school graduates in the health area and a negative association with the proportion of people aged 65 years and older. At the health area level, we found that the local availability of rheumatologists was an important factor associated with utilizing MSK specialists for A&R-related conditions in a cohort of respondents who have not been previously exposed to MSK specialists for musculoskeletal-related conditions.

A dedicated team approach enhances outcomes of osteomyelitis treatment.

To assess the impact of a dedicated musculoskeletal infection team, 70 musculoskeletal infections (traumatic and non-traumatic chronic osteomyelitis, Cierny-Mader Type III or IV) in 58 patients with were treated in two groups. Group I (43 infections) was treated with the assistance of an on-call infectious disease specialist. Group II (27 infections) was treated with the assistance of a dedicated musculoskeletal infectious disease specialist. Overall, there was a 42% success in Group I compared with 78% success in Group II. When stratified by infection type, in patients with Type III infections, there was a 56% success in Group I and a 90% success rate in Group II. For patients with Type IV infections, there was a 25% success rate in Group I and a 71% success rate in Group II. The participation of the dedicated musculoskeletal infectious disease specialist significantly improved patient outcomes.

Historical Vignette: Raynaud??s Phenomenon as Perceived by Musculoskeletal Specialists (1862-1957)

In Brief Polymerase Chain Reaction evidence of mycoplasma led to antibiotic therapy and was followed by clinical improvement in these seven patients. Roles of mycoplasma need further study.

BOOK AND MULTIMEDIA REVIEWS

With the intent of this book to discuss multidisciplinary methods of treatment its target audience consists of all musculoskeletal specialists including sports medicine physicians, physical therapists, massage therapists, and athletic trainers. The text is divided into 6 sections with 62 chapters. Six new chapters were added to this completely revised and enhanced third edition. Fundamental principles and theoretical aspects of sports medicine are discussed in Part A. Part B details regional problems and is symptom oriented discussing e.g., hip and groin pain and acute knee injuries. This section includes anatomy, differential diagnosis, assessment, and evidence-based or expert-advocated treatment options. Specific conditions are detailed from the most common to the “not to be missed” clinical presentations. Part C includes information on enhancing sports performance by way of e.g., nutrition, supplements, and sports psychology of sport. Part D focuses on conditions and treatment options for special groups including the young, female participants, the elderly, and disabled people. Part E covers the management of medical problems discussing among others emergency protocols, diabetes, osteoporosis, and rheumatic and inflammatory conditions. The final section discusses practical sports medicine with attention to medical care of teams and event coverage. The book is very well illustrated with full-color photographs, anatomical diagrams, diagnostic pictures, and flow charts useful for learning and clarification. The contributors to this edition consist of world-class clinicians and researchers. The chapters include recommended reading lists, websites, and recent references for each chapter. Practice pearls contain useful tips and suggested techniques for the clinician. There are also patient information sheets printable from a companion CD that summarizes patient presentations and potential treatment choices. I found the text easy to read and comprehensive. The information presented in this text can be applied to any active individual ranging from elite athletes to the active elderly population. Overall, this text is clinically relevant and is presented in a very usable format. Due to the extent of information presented in this text, relevant manual therapy techniques are not described in significant detail, but the text still provides a good overview of treatment options. I would highly recommend this book as an essential comprehensive text for any clinician working with active individuals.

Cost of Care and Patient-Satisfaction from Routine Referral to Nonsurgical Musculoskeletal Specialists in a Medicare Risk Plan

Overman, Steven S.; Kent, Daniel L.; Uslan, Donald W.; Lewis, Rayburn S. Author Information

A methodological appraisal of the impact of different classification procedures used in three different phases of the australian rheumatoid arthritis twin survey

To compare methodological aspects of the impact of different classification procedures used in three phases of a twin study examining genetic factors in the aetiopathogenesis of rheumatoid arthritis (RA). We have previously reported the results of a study of the aetiopathogenesis of RA based on the Australian Twin Registry (ATR). In the original 258 pairs self-reporting a diagnosis of RA in twin, co-twin or both, a very high false positive self-reporting rate for RA was noted (Phase 1). Subsequent diagnostic information obtained by a disease-specific questionnaire, followed by telephone interviews with subjects and review of information obtained by mail and telephone interview from the patient's general practitioner or musculoskeletal specialist, identified 23 'true' RA pairs (Phase 2). Pairwise concordance percentages for RA based on those 20 discordant and 3 concordant pairs were as follows: monozygotic (MZ) 21% (95% confidence interval (CI)=6-44%), dizygotic (DZ) 0% (95% CI=0-25%) (probandwise concordance MZ 35% (8.9-67.3), DZ 0% (0-50.3)). Given the potential effects of misclassification on data interpretation, we have further pursued the accuracy of diagnosis by a systematic clinical, serological and radiographical evaluation of the 23 RA pairs (Phase 3). In only one instance did more intense diagnostic investigation of the 23 pairs result in recategorization. The probandwise concordance percentages were recalculated: MZ=37.5%, DZ=0%. Our original contention that genetic factors play some part in the aetiopathogenesis of RA, but do not account entirely for its determination, has been substantiated at a higher level of confidence and at almost identical levels of concordance.