The Pregnant Arthroplasty Surgeon: A Women in Arthroplasty Committee Editorial.

BACKGROUND: Women orthopaedic surgeons face unique challenges during their careers. There are extremely low numbers of women in the field, particularly in the specialty of adult reconstruction. Factors contributing to low numbers of women entering this subspecialty include increased perceived physical demand relative to other fields, occupational hazards during pregnancy such as exposure to radiation and polymethylmethacrylate bone cement, concerns for work-life balance, and limited number of women within the subspecialty. The following editorial provides a framework to understand and manage the potential occupational hazards to pregnant and lactating surgeons, parental leave, and postpartum return to work. We aim to dispel any unfounded myths and provide evidence-based education that may help overcome these barriers. In doing so, we hope to encourage more women to consider adult reconstruction as a potential career. METHODS: Our primary method consisted of completing an extensive literature review on the past and current articles about the aforementioned barriers which may contribute to the low number of women entering adult reconstruction. After this literature search was completed, we composed a comprehensive editorial that provided evidence-based education and recommendations for medical professionals. CONCLUSIONS: Issues pertaining to parenthood, pregnancy, and lactation pose barriers to success for women in orthopedic surgery. These concerns may dissuade talented women from pursuing a rewarding career in adult reconstruction. Education on these issues is needed to help our early-career colleagues plan and care for their families. Clearly stated and published policies should be made available in all training programs, fellowships, and clinical practices to allow understanding and unbiased implementation. By being more inclusive, adult reconstruction will have access to the best possible surgeons, which will benefit not only patients but the field as a whole.

Factors That Influence Orthopedic Women Residents' Selection of Adult Reconstruction.

BACKGROUND: Stereotypes may discourage women from going into the historically male-dominated field of Adult Reconstruction. Other factors such as interest, confidence, and a sense of belonging may influence subspecialty choice. The objective of this study was to survey orthopedic surgery residents regarding their perceptions about Adult Reconstruction. METHODS: A validated survey evaluating social determinants of behavior was adapted to assess orthopedic surgery residents' perceptions of Adult Reconstruction. The survey was electronically distributed to residents from 16 United States and Canadian Accreditation Council for Graduate Medical Education-accredited residency programs. There were 93 respondents including 39 women (42%) and 54 men (58%). Study data were collected and managed using an electronic data capture tool. Descriptive statistics were reported for all continuous variables. Percentiles and sample sizes were reported for categorical variables. RESULTS: Women and men reported similar interest in Adult Reconstruction (46% versus 41%, P = .60). Fewer women reported that they were encouraged to go into Adult Reconstruction by faculty (62% versus 85%, P = .001). Women and men reported similar confidence in their own ability to succeed in the subspecialty of Adult Reconstruction. However, when asked about the ability of other residents, both sexes rated men as having higher levels of confidence. Women and men perceived other residents and faculty felt "men are better Adult Reconstruction surgeons," but did not personally agree with this statement. CONCLUSION: Women and men residents expressed similar rates of interest and self-confidence in Adult Reconstruction, but there were social barriers including negative stereotypes that may prevent them from pursuing careers in Adult Reconstruction.

Treatment of femoral head osteonecrosis in the United States: 16-year analysis of the Nationwide Inpatient Sample.

BACKGROUND: Many surgical interventions are used to treat osteonecrosis of the femoral head. The instance and distribution of these various procedures may give some insight into the practicing community's understanding of the efficacy of these treatments. We therefore sought to determine trends in the types and numbers of procedures performed for atraumatic osteonecrosis from 1992 through 2008 in the United States. QUESTIONS/PURPOSES: (1) How has the overall incidence of surgical treatment for atraumatic osteonecrosis changed over this time period; and (2) how has the percentage of THA performed for osteonecrosis (compared with joint-preserving procedures) changed over this time period? METHODS: The Nationwide Inpatient Sample database was used to collect information for all patients who had an International Classification of Diseases, 9(th) Revision diagnosis of hip osteonecrosis between 1992 and 2008. Procedures were collated according to frequency, and trends were analyzed for joint-preserving and joint-replacing procedures. RESULTS: The total number of procedures performed over this time period for osteonecrosis of the hip increased from 3570 procedures to 6400 procedures per year. In 1992, 75% (n = 2678) of the procedures performed to treat osteonecrosis of the hip were THA, which increased to 88% (n = 5632) in 2008. The percentage of joint-preserving procedures consequently decreased from 25% to 12% over this period. CONCLUSIONS: Previously, THA was believed to have poor survivorship and clinical results for the treatment of osteonecrosis of the hip, but reports since 1993 have suggested improved survivorship of these reconstructions. Our study suggests that surgeons have incorporated this into their practice patterns, in that an increasing percentage of patients with this diagnosis are treated with THA. Additionally, the total number of procedures performed for osteonecrosis has increased, which may reflect an improved awareness of this disease and more aggressive approaches to diagnosis and treatment.

Evaluating the function of total joint replacements - biomed 2010.

The primary function of hip and knee joints is to permit movement. The pathology of arthritic diseases leads to loss of articular surface anatomy and deformity which will impede motion. Consequently, one of the primary goals of total joint replacement is to restore mobility. The assessment of implants in the research and development phase includes the use of computer models, joint simulators and clinical trials. Clinical evaluation assesses motion, the ability of a patient to perform certain activities and the potential use of assistive devices. These assessments encompass patient examination and measurement of motion about the joint, instrumented tools (accelerometers, gait analysis), questionnaires (self-report, interview-based), and performance-based evaluations. In order to fully appreciate the functional outcome of a total joint implant, more than one type of assessment is required.

Resection arthroplasty for failed patellar components.

A total of 1,401 primary total knee arthroplasties (TKA) were reviewed; 44 (3.2%) had at least the patellar component revised. Nine of these knees (eight patients) had insufficient bone stock to allow reimplantation of another patellar component. Clinical data on the nine knees were obtained with recent follow-up evaluation, review of their medical records and radiographs. Evaluation included Hospital for Special Surgery (HSS) scores. Average follow-up was 4 years and 7 months, 2-year range (2 months to 8 years and 4 months). Common factors found in these nine knees included: thin patella after primary TKR status, osteoarthritis, good range of motion and patella alta. Results were good to excellent in seven knees and fair in two. The untoward associations with patellectomy such as quadriceps lag, extension weakness and anterior knee pain were not experienced. Resection of the patellar component, without reimplantation, is an acceptable alternative in revision TKA lacking adequate remaining bone stock.

What patient and surgical factors contribute to implant wear and osteolysis in total joint arthroplasty?

Total joint arthroplasty has been a successful operation for decades. Our current patients are younger and more active than those in the past. They place higher demands on themselves and have expectations commensurate with their lifestyles. Time-limited longevity with the large number of anticipated total joint replacement procedures and their potential burden to health care is a growing concern. In the past two decades, implant wear and osteolysis have been identified as major causes for the failure of otherwise well-functioning implants. Osteolysis can be divided into several categories: patient-specific, implant-specific, and the result of surgical factors. Although these categories are interrelated and not mutually exclusive, they enable us to build a framework in which to further advance our understanding of osteolysis and apply this information in a clinically relevant manner.

Comparison of two different fixation techniques for a segmental defect in a rat femur model.

Studies have attempted to identify the osteogenic effects of bone morphogenetic proteins using a rat femur model, which commonly involves the creation of a critical size defect followed by internal fixation of the femur. Among the most familiar fixation methods are either plating or intramedullary placement of a Kirschner wire (K-wire). There are advantages and disadvantages to each method; however, this study attempts to identify the best method by exploring the histological effects of each technique. The experiment involved two groups with no added treatment: Group P (plate fixation method) and Group K (K-wire fixation method). The animals were allowed a 4-week interval for the femurs to heal, and proximal, distal, and two midshaft cuts were examined under high-power microscopy after the fixation apparatus was removed. Group K exhibited a peculiar fibrotic healing pattern that followed the shaft of the then vacated K-wire and there was minimal new viable bone formation. Group P, however, exhibited a more natural ingrowth of newly formed bone that began at the proximal and distal cuts and proceeded centrally into the core of the defect. Due to the fibrotic tissue in Group K, this study shows that the model is insufficient due to the micromotion created and thus supports plating of critical defects as the fixation method of choice due to the creation of a stable healing environment.

Evaluation of the male reproductive organs after treatment with continuous sustained delivery of statin for fracture healing.

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used for the treatment of hyperlipidemia, and recent in vitro and animal data suggest that statins promote bone formation and increase bone strength. We examined the relationship between sustained continuous delivery of statin and fracture healing rates in adult male animals with femoral segmental fractures. Because statin affects the production of cholesterol we also evaluated the influence of statin, on adrenal and testicular steroidogenesis and the morphology of the reproductive tract tissues in animals receiving statin for a period of 12 weeks post surgery. Simvastatin significantly increased fracture healing and without significant influence on the body weights and the weights of the reproductive organs. Basal plasma LH, FSH and testosterone levels were not affected by active treatment with simvastatin. Reproductive tissue morphology was unchanged by local sustained release of statin. In conclusion, long-term simvastatin treatment delivered at a fracture target site did not influence testicular reproductive and endocrine function, but was able to effectively heal complicated segmental fracture.

Sustained release of OP-1 and antibiotics in treatment of femoral defects in male rats.

Osteogenic proteins (OP-1) promote osteoinduction. Formation of new bone growth in patients receiving OP-1 is not consistent, and is possibly due to the short half-life of the drug. In order to test the capacity of OP-1 to consistently produce bone in a fracture model, a drug delivery system was developed to prolong the action of OP-1. Fifteen Sprague Dawley male rats were randomly divided into three equal groups; Animals in group 1 served as control. Animals in groups 2 and 3 had a 5mm defect created in the left femur using a number six dental burr and a drug delivery capsule (TCPL) containing either antibiotic alone (sham) or antibiotic +OP-1. Body weights, blood, and X-rays were taken weekly. Femurs and organs were harvested 30 days post-op, and processed for histomorphometry. Data was analyzed using ANOVA and significant difference between the groups was determined using Student Newman Kuels (p < 0.05). The results showed complete bone healing in the OP-1 group with an evident callus formation. The osteoid tissue exhibited a proliferation of osteoblasts, which differentiated from the vascularized mesenchymal tissue. The complete bone healing using OP-1 sharply contrasted sham treatment, where an obvious injury was still seen at 30 days. Histologically sham animals exhibited the early stage of repair with evidence of blood clotting and mesenchyme with early formation of osteoblasts. Overall, OP-1 delivered in a sustained manner for 30 days caused increased bone formation in a defect model.

Stimulation of fracture healing by continuous delivery of demineralized bone matrix proteins and tobramycin.

Demineralized bone matrix (DBM) is an allogenous, bioabsorbable material that has long been used for its osteoinductive and osteoconductive properties. A significant complication experienced by physicians who perform bone defect filling surgery is the risk of subsequent bacterial infections and the inefficiency of oral antibiotics to provide adequate prophylaxis against microorganisms, especially Staphylococcus aureus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. In order to deliver both DBM and an efficient antiobiotic at high local concentrations without deleterious systemic effects, a ceramic sustained delivery system was implanted and monitored over the course of 30 days for bone regeneration, infection, and systemic effects. Twenty-five adult Sprague Dawley albino male rats were used in the experiment. They were randomly divided into five equal groups. Animals in group 1 were used as control, group 2 animals had a created 5mm defect, in group 3 defect induced and implanted with devices loaded with antibiotic (tobramycin) alone, group 4 had a created defect plus DBM, and group 5 had a created defect, plus tobramycin (which is effective against the aforementioned organisms) and DBM. At 30 days post-implantation, the experimental animals showed no significant difference in weight when compared to the control and sham animals. X-rays taken at this time showed the experimental femurs to be totally healed and virtually indistinguishable from control. Initial dissections revealed that the implants were accepted by the hosts as shown by the fibrous, vascularized sheath that surrounded the femurs and capsules. The implants were found to be in close contact with the cancellous bone and none of the sheaths showed signs of infection. Macroscopically, no defect could be detected in the experimental animals, while little regeneration was observed in the femurs of the sham animals.

Effects of spaceflight on the attachment of tendons to bone in the hindlimb of the pregnant rat.

The objective of this study was to determine the effects of spaceflight on the structure of the tendon-bone junction (TBJ). Pregnant rats either flew in the space shuttle Atlantis (flight group; F) or were exposed to simulated launch and landing protocols (synchronous control group; SC) during days 9-19 of pregnancy. Following birth of their pups, maternal hindlimbs were studied using scanning electron and light microscopic histomophometric techniques. The tibial and calcaneal tuberosities, the fibular head, and the tibia-fibula junction were studied. Myofiber density and cross-sectional area of the quadratus femoris and soleus muscles and diameters of the calcaneal and patellar tendons were also evaluated. Cortical erosion was significantly greater at the tibial tuberosity and the fibular head in F animals compared to SC animals (P < 0.001). Sharpey fiber density was significantly less at the tibial tuberosity and fibular head in F animals compared to SC animals (P < 0.001). The myofiber area of both the soleus and quadratus femoris muscles and the diameters of both calcaneal and patellar tendons were significantly less in F compared to SC rats (P < 0.05). Our data illustrate that the TBJ morphology is affected by spaceflight at the attachment sites of the soleus and quadratus femoris muscles in pregnant animals, which could adversely affect their physical properties. These atrophic TBJ changes could have resulted from atrophy of the adjacent muscles and their tendons. Atrophic changes in the structure of the TBJ could predispose an animal to injury following spaceflight, when normal gravity conditions are reestablished.

Stimulation of osteogenesis by means of sustained delivery of various natural androgenic hormones.

Sex steroids play an essential role in the maintenance of bone health throughout life, and the mechanisms by which these effects are mediated in a subject of much controversy. Osteoblast cells appear to be stimulated by androgens in vitro, however their use in vivo is limited due to the virilizing side effects as well as alterations in the lipoprotein profiles. The use of targeted sustained release of anabolic steroids may stimulate fracture healing without untoward side effects. The specific aims were: (1) to compare fracture healing in a rat femoral defect model using tricalcium phosphate lysine (TCPL) drug delivery systems to deliver T, DHT and AED for long duration; (2) to quantify the level of steroid delivered from the system; and (3) to use bone histomorphometric techniques to analyze new bone formation at the defect site. A total of 125 adult male Sprague Dawley were obtained and acclimatized for two weeks in the animal care prior surgical procedures. All animals were kept on a 12-hour day/night cycle and were fed Purina rodent chow and water ad libitum. The animals were randomly divided into five equal groups (n = 25 per group). Group 1 animals were used as the intact control. Group 2-5 animals were placed under anesthesia and a standard approach was used to create a 6-mm defect using a dental burr in the midshaft of the femur. Group 2 animals were implanted with a sham TCPL delivery system adjacent to the defect. Animals in groups 3, 4, and 5 received a TCPL delivery system loaded with T, DHT, and AED, respectively. Animals were weighed, x-rayed, and blood samples were drawn on a weekly basis. The rats were sacrificed after 3, 6, 9 12 and 15 weeks and reproductive, vital organs, and fracture calluses were collected and analyzed. Morphometric analysis of the femurs revealed that the use of sustained delivery of DHT induced remarkable bone ingrowth compared to the sham and other experimental groups. All treated femurs appeared healthy and normal bone architecture was observed by the end of the 6 week phase. Measurements of the inner perimeter of the bone on the endosteal side showed significant reduction in the androgens treated animals. The quantitative findings confirms our preliminary studies and endorsing the previous data that the sustained delivery of T or its metabolite (DHT) can stimulate the osteoblastic activities in which eventually causes an increase in the cortical bone density.