In many urban areas of the United States, the rates of HIV infection are astonishingly high. In Washington, DC, for instance, 3% of the adult population and 6% of African American males are infected.⁵⁸ In many urban areas in the United States, it is estimated that 25% to 40% of HIV-infected individuals are unaware of their HIV status. Some of these patients are not aware that they are participating in high-risk behavior. Others do not recognize the advantages of early diagnosis and treatment. Thus, a considerable number of patients consulting orthopedists about musculoskeletal problems are unaware that they are infected.

Given that the epidemic continues to spread, and that individuals infected with HIV are living longer, nearly all practicing physicians will encounter patients with HIV in their practice. Natural history studies indicate that HIV-infected individuals not receiving antiretroviral therapy usually live 8 to 12 years from the time of initial HIV infection to their first major acquired immunodeficiency syndrome (AIDS) manifestation,^3,¹⁰¹ after which AIDS patients without antiretroviral treatment survive for 1 to 2 years. However, now that effective and tolerable antiretroviral regimens are available, patients live for decades, often dying from the complications of aging that are identical to those of HIV-uninfected patients.^26,^42,^77,¹¹⁹

HIV-infected patients often lead active lives, participating in activities for fitness and recreation, as well as in competitive high school, college, and professional sports. Furthermore, weight training to build lean muscle mass is considered a standard component of treatment and of prevention of wasting syndrome and lipodystrophy in HIV-infected individuals. Consequently, these patients experience trauma and degenerative processes just as their uninfected counterparts do, and they come to orthopedic attention for processes that are clearly related to HIV infection, and for syndromes that are related to the same traumatic and aging processes that afflict HIV-uninfected patients.

Careful evaluation and familiarity with the complex nature of HIV infection will help ensure accurate assessment and appropriate treatment of HIV-infected individuals with orthopedic and rheumatic conditions. Orthopedists need to recognize that the population of patients whom they may see with HIV infection will include individuals infected by homosexual and heterosexual activity, individuals infected by intravenous drug abuse, and individuals infected domestically and abroad. In short, the possibility of HIV infection needs to be considered in the entire range of patient populations. Time and time again, physicians who believe that they can recognize HIV-infected patients without obtaining serologic testing or a specific testing history are proven wrong.

HIV Virology

Human T-cell lymphotropic virus type I (HTLV-I), HTLV-II, and HTLV-III (HIV-1 and HIV-2) are the four known human retroviruses. HIV-1, which is by far the most important retrovirus of humans currently known, has been established as the causative agent of AIDS. HIV-2 causes a similar but milder disease, primarily in Western Africa. Retroviruses are a group of RNA viruses that produce reverse transcriptase, an enzyme that converts viral RNA to proviral DNA. This proviral DNA is then integrated into the chromosomal DNA of the host cell.

The hallmark of HIV disease is a profound immunodeficiency resulting primarily from progressive quantitative and qualitative deficiency of CD4 helper T lymphocytes.⁶⁴ This subset of CD4 helper T cells is defined by the presence of the CD4+ T-lymphocyte molecule on its surface. Monocytes, macrophages, and follicular dendritic cells express the CD4 molecule on their surfaces as well. This CD4 molecule, together with coreceptors, serves as the primary receptor for HIV. Although numerous direct and indirect mechanisms that contribute to CD4+ T-lymphocyte cell depletion and dysfunction have been identified in vitro, the manner in which HIV infection results in a progressive decline in CD4+ T-lymphocyte cell counts and immune function remains unclear.

HIV infection is persistent and is associated with an extended period during which the patient has no symptoms and has normal routine laboratory values. Infection stimulates an immune response to HIV that initially appears to hinder viral replication but fails to eradicate the virus.^4,^36,⁵⁷ Without therapy, nearly all infected individuals ultimately experience a progressive deterioration in immune function that results in susceptibility to HIV-related complications and opportunistic infections.^42,^48,⁶⁴ Contemporary combination antiretroviral therapy reduces circulating virus, augments CD4 counts, reduces HIV-related complications, and prolongs survival.⁴²

Transmission of HIV

HIV is transmitted between humans by the exchange of body fluids via three principal routes: sexual contact, parenteral inoculation, and vertical transmission from an infected mother to her child.

Body fluids identified as potentially significant sources of HIV exposure include blood, semen (including pre-ejaculatory fluid), vaginal secretions, breast milk, cerebrospinal fluid, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, amniotic fluid, and any body fluid containing blood.^32,⁹⁰ Body fluids considered to represent minimal risk for transmission of HIV include feces, nasal secretions, sputum, saliva, sweat, tears, urine, and vomitus, unless contaminated with visible blood.

The quantity of virus isolated from a body fluid varies by site and stage of HIV infection. Viral burden in blood and other fluids is highest during acute infection before seroconversion.^36,⁵⁷ However, even when the circulating viremia is quantitatively high, HIV has not been shown to be transmitted by casual contact or by insect vectors such as mosquitoes.

Sexual Transmission

Throughout the world, the predominant mode of HIV transmission is sexual contact. Historically, homosexual contact has accounted for the preponderance of sexual transmission in developed countries. In developing countries, most sexual transmission of HIV has occurred through heterosexual contact. Heterosexual transmission has been increasing rapidly in the United States.

In the United States, aggressive educational programs targeting high-risk behavior in homosexual men at first resulted in an increase in “safer sex” practices and a decline in the incidence of new cases. However, disturbing trends indicate a rise in unsafe sexual practices among homosexual men.

The incidence of new cases of AIDS contracted through heterosexual contact is increasing in the United States, particularly among women, African Americans, and teens and young adults.²⁴

Regardless of the mode of sexual contact, it is evident that both behavioral and biologic factors contribute to the transmission of HIV infection.²⁶ Transmission of HIV is strongly associated with receptive anal intercourse. Even when intact, the thin, fragile rectal mucosa offers little protection against infection from deposited semen. Moreover, anal intercourse, as well as other sexual practices involving the rectum, such as “fisting” and insertion of objects, traumatizes the rectal mucosa, thereby increasing the likelihood of infection during receptive anal intercourse.

HIV can be transmitted to either partner through vaginal intercourse. It is estimated that the chance of transmission of HIV by this means from a man to a woman is 20-fold greater than from a woman to a man. This greater risk in women is thought to be due in part to prolonged exposure to infected seminal fluid by the vaginal, cervical, and endometrial mucosa. Transmission of HIV is also closely associated with genital ulceration. Important cofactors in the transmission of HIV include infection with herpes simplex virus, Treponema pallidum (syphilis), and Haemophilus ducreyi (chancroid).²⁶ Similarly, genital inflammatory conditions such as cervicitis, urethritis, and epididymitis associated with gonorrhea and chlamydia have been linked to the transmission of HIV. Although oral sex appears to be a less efficient mode of transmission of HIV, it is a misperception that oral sex is a form of “safe sex.” HIV transmission has been reported as resulting solely from receptive fellatio and insertive cunnilingus. The risk appears to be increased by the presence of oral ulcerations and gum bleeding.

Male circumcision has been shown to reduce male acquisition of HIV among heterosexual men in Africa. It is plausible that circumcision would reduce heterosexual transmission in the United States, but this has not been proven in a clinical trial. It is also uncertain how effective circumcision would be among homosexual males, especially those who do not engage exclusively in insertive intercourse.

Alcohol consumption and drug use have been associated with the transmission of HIV as well. The disinhibition and poor judgment that accompany alcohol and drug use often lead to unsafe sexual behavior. Other important risk factors for infection include the number of sexual contacts, having sex with a prostitute, being a prostitute, being a sex partner of an infected person, being a sex partner of an intravenous drug user, and having a history of other sexually transmitted diseases, particularly ulcerative genital disease.

Transmission Associated With Intravenous Drug Use

HIV infection in intravenous drug users is highly prevalent throughout the world. Risk factors for HIV infection in intravenous drug users include frequent injection, sharing needles with many individuals, anonymous sharing of needles and other paraphernalia, cocaine use, and the use of injection drugs in geographic locations with a high prevalence of HIV infection, such as inner city areas.³³ This population appears to be functioning as the primary reservoir for the rapid spread of HIV infection into the heterosexual population throughout the world.^24,^26,⁸⁹

Although the risk of infection is highest with direct sharing of needles, the sharing of drug paraphernalia, such as syringes, water, “spoons” and “cookers” (used to dissolve drugs in water and to heat drug solutions), and “cottons” (small pieces of cotton or cigarette filters used to filter out particles that could block the needle), can also increase the risk of transmission. Street sellers of syringes and needles often repackage and sell such equipment as “sterile.” Needle or syringe sharing for any use, including skin popping and injecting anabolic steroids, can put one at risk for HIV and other blood-borne infections such as hepatitis B and C. Athletes have transmitted HIV to each other by sharing syringes for injection of illicit drugs designed to enhance performance.

Transmission by Blood Transfusion and Bone Grafts

Currently, blood products almost never transmit HIV infection in the United States. In this country, all blood products are screened for HIV by serologic techniques and by patient questionnaire related to high-risk behaviors and past infections. Routine screening may fail to detect occasional cases of HIV infection, usually in very recently infected donors. Such transmission occurs only a few times per year when blood is appropriately screened. The current risk is estimated to be 1 in 2 million transfused units in the United States.^18,^44,^79,^80,¹²⁰

Outside of the United States and Western Europe, considerable variability has been seen in the screening of blood products. HIV transmission by blood transfusion is a substantial risk in many parts of the world. In the developing world, travelers and expatriates are often reassured that the blood they received came from reliable donors or was screened, but often the screening processes are far inferior to those used in this country.¹²⁰ Orthopedists must be aware that HIV can also be transmitted by bone grafts. HIV infection of bone is well documented, although such events in the current era of screening should be extremely rare, at least in the United States and Western Europe.^16,^29,^92,¹¹⁵ The primary safeguards against potential transmission of HIV by bone allograft are serologic testing of donor patients and careful questioning regarding high-risk behavior.⁷⁹ The freezing step in bone tissue banking probably results in further reduction of the risk of transmission.^16,¹¹⁵

Transmission Related to Sports

The transmission of infectious agents during sports has become a major interest in the United States, with attention focused on methicillin-resistant Staphylococcus aureus (MRSA). Close person-to-person contact on the athletic field and in the locker rooms, as well as sharing of clothing, combs, razors, and towels, provides ample opportunity for transmission of microorganisms by skin-to-skin or skin-to-inanimate object contact. Herpes simplex virus (HSV) is another example of a pathogen that has been documented to be transmitted by skin-to-skin contact during an athletic event.

However, in contrast to MRSA and HSV, no cases of HIV transmission have been documented to date during participation in athletic activities. The risk of transmission during sports participation is estimated to be extremely low, and transmission would be expected to occur only after blood from an infected individual has come into contact with the mucous membranes or open skin of an uninfected athlete or trainer. Without visible blood, no measurable risk of HIV transmission through sports activities has been found. Human bites in theory could transmit HIV, but such bites present very, very low risk. When members of the health care staff deal with injured players, therefore, the risk of HIV transmission is extremely remote, especially if the athletic staff members have intact skin, and if they use gloves and barriers to prevent blood contact.

In their joint position statement on HIV and other blood-borne pathogens in sports, the American Medical Society for Sports Medicine and the American Academy of Sports Medicine recommend that sports medicine practitioners should play a role in the education of infected and uninfected athletes, their families, and the sports community regarding disease transmission and prevention.¹²² Athletes should be advised that it is their responsibility to report wounds and injuries in a timely manner. If an athlete is bleeding, sports participation should be interrupted. After the wound stops bleeding and has been antiseptically cleaned and securely bandaged, participation may be resumed. Universal precautions and basic principles of hygiene should be observed. In addition, the position statement asserts that sports medicine practitioners should be knowledgeable about management issues involving HIV-infected athletes and should maintain their confidentiality. Such confidentiality policies have clearly mandated that athletes with HIV infection should not be managed in public forums differently from uninfected athletes.

Occupational Transmission of HIV from Patient to Provider

In the 1980s, special concern arose about transmission of HIV from patients to providers, especially among surgeons because of their exposure to needles and to body fluids during emergency procedures. During that time, prominent orthopedic surgeons refused to perform orthopedic procedures on HIV-infected patients because of the risk to staff and the short anticipated life span of these patients. As more information has become available, data-based policies have been established that confirm the concept that the risk of transmission of HIV to operating room staff by any mechanism (needlesticks, mucosal splashes, bone dust or fragments) is not zero, but is vanishingly small.^55,^56,^65,⁷¹ Other pathogens such as hepatitis B and hepatitis C pose far greater risks to nonimmune health care providers.^30,⁸¹

Given their prolonged and repeated exposure to potentially large volumes of blood, surgeons’ concerns about possible occupational acquisition of HIV infection are understandable. However, studies have documented that nurses, followed by house staff and operating room nurses and technicians, are at greatest risk for occupational sharp instrument injuries ⁹¹—the type of injury most likely to be associated with transmission of HIV infection. Factors that may influence the risk of HIV transmission during surgery include the skill and training level of the surgeon, the surgical procedure being performed, the volume and duration of blood exposure during the procedure, the number of procedures performed, and the conditions under which the procedure is performed—that is, emergency versus elective.⁹ Practices undertaken to reduce the risk of exposure to HIV and other blood-borne pathogens include restriction of operating room personnel to essential and experienced staff, double-gloving, use of protective eyewear and appropriate garment shields, and minimization of sharp instrument use.^9,^20,¹⁰⁶

Although HIV-1 has been demonstrated to remain viable in the cool vapors and aerosols produced by several common surgical power instruments, aerosols have not been documented to cause any transmissions of HIV.⁷² It is interesting to note that no infectious HIV has been detected in aerosols generated by electrocautery or by manual wound irrigation syringes.

The risk of becoming infected with HIV after any exposure to body fluid of any type is low. When blood or infected fluids come into contact with intact skin, the risk of transmission is negligible. For mucosal exposure, the risk is about 0.09%. For needlestick injuries, the likelihood of transmission is about 0.33%.

Each exposure must be individually evaluated in terms of determining risk. How much circulating virus the source patient had at the time of the event, what type of body fluid or tissue was involved, how deep or extensive the wound or exposure was, and how thoroughly and rapidly the injured area was irrigated are all relevant factors. There is no formula for assessing these factors and estimating the risk for transmission.

Although nurses have fewer exposures per year than surgeons, there are more nurses than surgeons in the United States. Thus, nurses are most heavily represented among HIV occupational exposures. As a group evaluated for lifetime exposures, a higher percentage of nurses have had an exposure (37.9%) than physicians who are residents or fellows (11.4%), attending physicians (10.7%), surgery attendings (9.0%), phlebotomists (5.4%), or nonlaboratory technologists (4.7%).

Between 1981 and 2006, 57 health care workers in the United States acquired occupational HIV infection through occupational exposure to an HIV-infected patient. No new cases have been reported since 2000, although some cases are still being assessed. Of the 57 health care workers with well-documented cases, 48 had percutaneous exposures (puncture or cut), 5 had mucocutaneous exposures, 2 had both exposures, and 2 had unknown routes of exposure.

In one notable study, a survey performed with 699 surgeons-in-training at 17 medical centers revealed that the mean number of needlestick injuries by the final year of residency was 7.7, and that 99% of residents had had at least one needlestick injury, often with a high-risk patient. Many of these occurred because of haste or fatigue.^53,⁸⁴

Orthopedic procedures, in general, have been shown to have a relatively low percutaneous injury rate when compared with other surgical subspecialty procedures. In one observational study, total knee replacement and open reduction plus internal fixation of the hip were shown to have percutaneous exposure rates of 8% and 7%, respectively. All other orthopedic procedures were shown to have a combined percutaneous exposure rate of 2%.¹²⁶ The incidence of skin and mucous membrane contact with blood has been estimated to be 16.7 contacts per 100 orthopedic procedures.¹²⁷ To date, no seroconversions among surgeons and no seroconversions due to suture needle exposures have been confirmed.^43,^53,^81,⁸⁴

Universal precautions recommended by the CDC to protect health care workers from contact with potentially infectious body fluids emphasize barrier techniques to prevent skin and mucous membrane exposure to blood and other body fluids.^22,²⁸ As noted earlier, it is not always obvious who has HIV infection because a substantial fraction of cases are unrecognized, and because so many patients are unwilling to acknowledge that they are at high risk because of sexual or drug-using behavior. Hospitals are encouraged to test patients universally, allowing patients to “opt out” rather than “opt in.” However, many hospitals have not yet adopted this policy. Therefore, all patients should be assumed to have blood-borne pathogens such as HIV or some other known or unknown pathogen.

A major limitation of barrier precautions is that they often fail to prevent injury with sharp instruments (e.g., needlestick punctures, cuts), which is the source of more than 80% of confirmed cases of occupationally acquired HIV infection. Nonetheless, as noted earlier, the use of gloves appears to decrease the amount of blood transferred in simulated needlesticks, and the implementation of universal precautions has been temporally related to a decrease in the frequency of needlesticks.^10,⁸⁷

In 1992 (almost 2 decades ago), the U.S. Occupational Safety and Health Administration (OSHA) established mandatory regulations requiring national standards for the prevention of occupational exposure to hepatitis B and HIV, including guidelines for disposal of sharp instruments, such as not recapping needles and using designated boxes. A review of the circumstances of reported exposures suggests that the risk of transmission could have been decreased or prevented if universal precautions and OSHA guidelines had been followed. This observation is supported by an observational study of percutaneous injuries during surgery, in which injury often occurred when fingers were used instead of instruments to hold tissue or suture needles during suturing, or when instruments were being handled by a coworker.¹²⁶

Although exposure to HIV is a significant concern for health care workers, exposure to other pathogens such as hepatitis B and C, Mycobacterium tuberculosis, and, less commonly, HTLV-I and HTLV-II should also be cause for concern. In fact, the risk for infection with hepatitis B virus after percutaneous injury ranges from 2% to 40% (if the injured person is unvaccinated—a rare occurrence in the United States) and for hepatitis C from 3% to 10%, as compared with 0.3% for HIV.⁵⁶

Thus, although health care workers often worry more about HIV than about other blood-borne pathogens, a greater number of health care workers die each year as the result of occupationally acquired hepatitis B than HIV. Thus, vaccination against blood-borne pathogens should be mandatory for health care workers. An effective vaccine against hepatitis B is available, but unfortunately, no effective vaccine against HIV or hepatitis C has been discovered.

HIV-Infected Health Care Workers: Risk of Transmission to Patients

In the past, there was concern that health care workers infected with HIV might transmit HIV to their patients.⁵⁰ Few controversies involving HIV infection have generated as much media or public sector commentary as the highly publicized incident of HIV transmission from a Florida dentist to at least six of his patients 2 decades ago.^31,³⁴ Documentation that the dentist was the source of infection was based on lack of alternative substantive risk factors in several of his patients, the fact that all patients underwent multiple procedures, including extractions after onset of the dentist’s symptomatic disease, and genetic analysis of HIV strains. Although it is evident that the dentist was the source of infection in these patients, the mechanism of transmission remains unclear.

Two reports from Europe have also described possible transmissions. Lot and associates reported a case of probable transmission of HIV from an orthopedic surgeon to a patient in France.⁸² Other reports followed.^13,^25,⁵⁵

In another investigation, after HIV infection was diagnosed in a surgeon in Israel in 1995, serologic tests were obtained from 983 patients of the infected surgeon.²⁵ One patient tested positive. That patient, a 67-year-old woman, had no other identifiable risk factors for HIV exposure. She tested negative for HIV before placement of a total hip prosthesis with a bone graft. She subsequently underwent hip aspiration and removal of the prosthesis by the same surgeon. This woman received 2 units of packed red blood cells after the third procedure. However, the donor of the bone graft and both units of blood tested negative for HIV infection. The patient had no reported sexual exposure to HIV. In addition, the surgeon reported a high frequency of intraoperative injury. Molecular analysis indicated that the viral sequences obtained from the surgeon and the patient were closely related.¹¹ The patient did undergo noninvasive tooth whitening in Indonesia, where HIV infection is prevalent. Thus, the mechanism and date of transmission could not be definitively established. It appears as though the most likely source of infection was the surgeon.⁵⁵

Using look-back studies and other data, the CDC estimates the risk of HIV transmission from provider to patient to be 1 in 2.4 to 24 million cases.* Thus the risk of provider-to-patient transmission of HIV during invasive procedures does exist, but this risk is exceedingly small.

In 1991, the CDC issued guidance for managing HIV-infected health care workers. In this document, the CDC recommended that for procedures that were “exposure prone” in which an HIV-infected provider was involved, a review of safety issues during the planned procedure should be conducted by an expert panel, or the patient should be notified regarding the provider’s HIV status. These guidelines were extremely controversial, were not widely implemented, and have not been updated since that time.