Published 4/1/2013
Thomas J. Moore, MD

Informed Consent—It’s Complicated

Use of bone substitutes and bone healing enhancers demands attention

Informed consent is a particularly thorny issue in medical ethics. In general, orthopaedists and orthopaedic residents are aware and compliant, although the lack of clear guidance on what, when, and how much to say is problematic.

Several factors have been identified as optimal in obtaining informed consent, especially in the avoidance of litigation. For example, informed consent should be obtained in the clinic or office, rather than in the preoperative area. Informed consent documents may include a comprehensive list of generic potential complications or a list specific to the planned procedure; it is unclear which is sufficient. In terms of the medical record, informed consent is best documented by either a preoperative note dictated by the surgeon or a postoperative note that includes documentation of the informed consent process.

Informed consent is not routinely obtained for using allographic bone in orthopaedic procedures. It is, however, usually obtained for the harvesting of autogenous bone graft, because pain and infection at the harvest site have been documented, and autogenous bone graft usually requires a separate surgical incision.

The use of allograft material can potentially transmit infectious material to the recipient. Studies have shown significant positive cultures in allographic tissue, especially in allographic tissue used for anterior cruciate ligament reconstruction. But little correlation has been found between positive preoperative cultures and subsequent clinical infections, and infectious transmission of either bacteria or virus with the use of allographic tissue is extremely rare.

Demineralized bone matrix, a product derived from cadaveric bone, is used to enhance fracture healing or fusion rate. No cases of transmission of infectious organisms due to the use of demineralized bone matrix have been documented. The efficacy of bone substitutes, such as calcium phosphates or hydroxyapatite, for treatment of bony defects or for augmentation of fusions has shown to be equivalent to the use of autogenous bone graft, the “gold standard.”

The use of bone-forming adjunctive modalities, such as recombinant human bone morphogenetic proteins (rhBMPs), to enhance fracture healing or fusion has recently received attention in the lay press. Isolated complications with the use of rhBMP in spine fusions, such as retrograde ejaculation in males, have occurred in clinical studies, but initially were not reported, because the study authors deemed the complications as not statistically significant. The use of rhBMPs in cervical spine fusion has resulted in significant edema with resultant compromise of tracheal air flow.

Most of the use of rhBMPs in orthopaedics is off-label, which means that the product has not been approved for such use by the U.S. Food and Drug Administration (FDA). Physician-directed use of such products for uses not approved by the FDA is allowable because the FDA does not regulate physician practice; its statutory authority extends only to the regulation of the manufacturers of drugs and medical devices and listing of known complications.

Physician-directed (off-label) use of devices or drugs has been approved by some state legislatures, and it is generally acknowledged that physicians should be able to apply their best medical judgment in the use of off-label devices or drugs. Although current regulations on informed consent do not require a physician to note that he or she is using a product such as rhBMP off-label, the planned use of allografts, bone substitutes, and bone enhancers in surgery should be disclosed in informed consent.

The document should be carefully worded. The general population does not usually understand the medical terminology used in informed consent. Therefore, it is not necessary to go into medical detail concerning the surgical use of biologics. Furthermore, the use of such terms as “unapproved” or “unregulated” may cause unnecessary anxiety in patients.

At all times, the general medical ethics concept of beneficence, which holds that the well-being of the patient is the main focus of medical practice, should be the guiding principle of informed consent. The modern concept of informed consent should provide the patient with an understandable discussion of the planned procedure, the possible risks, and possible alternatives to the procedure. If the surgeon has any possible conflicts, such as consultant status with the company providing the biologics, this should be disclosed in the informed consent.

Thomas J. Moore, MD, is a member of the AAOS Biological Implants Committee; he can be reached at Thomas.moore@emory.edu

Dr. Moore reports no conflicts.