Table 1. National Institute for Occupational Safety and Health steps for the determination of work-relatedness of a disease
Source: Melhorn JM, Talmadge JB, Ackerman WE III, Hyman MH: AMA Guides to the Evaluation of Disease and Injury Causation (2nd ed.). American Medical Association Press; 2013.


Published 7/5/2022
J. Mark Melhorn, MD, FAAOS; R. David Bauer, MD; Rebecca Araujo

Review Key Concepts about Medical Necessity in Orthopaedics

Upcoming AAOS workers’ compensation course delineates appropriate medically necessary care

For orthopaedic surgeons, medical necessity is the gatekeeper to reimbursement for medical services provided. Each year, the AAOS Workers’ Compensation and Musculoskeletal Injuries Course (see Sidebar) offers current perspectives on determining causation and offering medically necessary musculoskeletal care. This article reviews key concepts about medical necessity, which will be covered during the course, Nov. 4 to 6 in San Antonio, Texas.

Defining medical necessity
Medical necessity is a U.S. legal doctrine related to activities which may be justified as necessary, reasonable, and/or appropriate based on evidence-based clinical standards of care. In contrast, unnecessary healthcare would lack such scientific evidence. Medically necessary, reasonable, and/or appropriate (MNRA) care is care that is needed to diagnose or treat an injury, condition, disease, or its symptoms and that also meets accepted standards of medicine. Additionally, MNRA care does not exceed the patient’s medical need and is at least as beneficial as an existing and available medically appropriate alternative.

Utilization reviews and treatment guidelines increase physicians’ burden to determine medical necessity in their practice. Unfortunately, there is no easy answer. In one scenario, a certain treatment may meet the criteria, but in another situation, the payer may deny payment for the treatment.

Physician opinion must be supported by appropriate scientific evidence. Determining treatment appropriateness based on personal experience or training is insufficient. Although all physicians use evidence in their decisions, some may overlook the quality of that evidence. Rigorous grading schemes to determine “levels of evidence” have been created to evaluate current best science. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system is the most commonly used classification.

Practice guidelines, such as those developed by the American College of Occupational and Environmental Medicine or the ODG return-to-work guidelines from MCG Health, are often used or required by state workers’ compensation commissions to establish reasonableness. Additionally, multiple professional organizations, insurers, and government entities have developed orthopaedic treatment guidelines, such as the AAOS Clinical Practice Guidelines and Appropriate Use Criteria, available at www.​

Establishing medical necessity
There are two common instances where orthopaedic surgeons consider medical necessity. The first involves the traditional patient-physician interaction. After the treating surgeon considers the patient’s history, physical examination, and relevant clinical studies, the surgeon determines a diagnosis and what treatment options may be medically necessary to address the diagnosis and/or symptoms. The surgeon presents the treatment options, outcomes, and expectations to the patient using a “shared decision-making” method.

The second instance involves determining what MNRA musculoskeletal medical care is in a legal context, such as in a workers’ compensation or tort case. The legal context adds additional requirements for the determination of MNRA.

In a legal context, establishing medical necessity requires a correct diagnosis. Then, the orthopaedic surgeon can determine whether the incident in question for the workers’ compensation or tort case caused or contributed to the diagnosis (depending on the legal threshold or jurisdiction), then follow the National Institute for Occupational Safety and Health’s six-step process to establish reasonable and appropriate treatment options (Table 1).

The orthopaedic surgeon reviews the medical literature for anticipated, expected, and predicted responses to treatments in order to inform a treatment recommendation. Objective evidence of a treatment response would support a physiological cause for the symptoms. On the other hand, inconsistent responses or worsening of the condition that conflicts with the natural history of the diagnosis would suggest nonphysiological components. In that case, the selected treatment may initially have been appropriate, but failure to demonstrate improvement would not support its continuation.

Adjudication Process
There are times when payers employ case adjudicators to review the orthopaedic surgeon’s treatment plan, including additional testing ordered, surgeries recommended, and/or the care delivered by expanded providers (i.e., nurse practitioners, physician assistants, physical therapists, chiropractors). In such cases, an orthopaedic surgeon uninvolved in the patient’s care is typically assigned the responsibility of determining necessity. The orthopaedic surgeon acts as expert and arbitrator, performing an independent medical exam or records review, then explaining whether the treatments rendered were medically necessary.

Example: Mr. Smith
Mr. Smith is a 55-year-old carpenter who twisted his right ankle while at work. He was walking across the construction site, and his foot rolled into a hole, causing him to twist his ankle and fall. He was seen in the ED with a painful right ankle that was slightly swollen and tender to the touch with no ecchymosis. He reported being unable to bear full weight. His radiographs were normal. The diagnosis was low ankle sprain grade I. He was prescribed medication and told to stay off the foot for seven days.

At one week, he tried to return to work but reported continued pain even with his high-ankle–laced work boots. He reported pain with weight bearing to his primary care physician (PCP). The physical examination found no swelling, ecchymosis, or instability; a negative anterior drawer test; and a negative talar tilt test, but slight pain in the anterior talofibular ligament with pressure. Mr. Smith requested an MRI of the ankle because he read on the internet that radiographs miss soft-tissue injury. The MRI was reported as normal, with intact anterior talofibular ligament and fibular collateral ligament. No other acute or chronic changes were observed.

At two weeks, the ankle was still sore at the end of the day. Mr. Smith returned to his PCP and asked to undergo physical therapy (PT). PT for eight visits (twice weekly) provided motion exercises and then progressed to strengthening, proprioception, and activity-specific exercises.

At six weeks, Mr. Smith returned to regular work. The ankle felt better, with some soreness at the end of the day. During his next PCP visit, he asked for eight more PT visits.

At 12 weeks, he had completed all 16 PT visits and reported that his ankle was back to normal. His PCP released him, with follow-up as needed. Mr. Smith had reached maximum medical improvement, and his workers’ compensation claim was closed without any permanent physical impairment.

Mr. Smith Explained
Using the definition above, Mr. Smith’s initial ED visit would fit the MNRA requirement because the visit determined the diagnosis and established a reasonable and appropriate evidence-based treatment.

At one week, based on his medical history, physical examination, and previous radiographs, the MRI provided would not meet the MNRA criteria. Additional radiographs (i.e., external rotation stress view or varus stress view) may have been reasonable but probably not appropriate based on the medical history and physical examination.

At two weeks, a grade I sprain has usually significantly improved, allowing for normal activities. In this case, Mr. Smith still complained of pain and then underwent PT for eight sessions. Some individuals require motivational assistance with their recovery, and PT can provide the guidance and reassurance necessary in addition to the therapeutic treatment modalities delivered. Therefore, the PT would be reasonable, even if it does not meet specific medical practice guidelines to be considered medically necessary.

After six weeks, the additional PT visits would fail to meet the requirement of objective improvement in functionality (i.e., activities of daily living or work) and therefore would be denied coverage based on a lack of scientific evidence by most utilization review processes.

The process of utilization review and the role of treatment guidelines have been established by commercial and federal insurance programs. Understanding treatment guidelines can help the physician avoid unnecessary delays in treatment, expedite recovery, and improve outcomes for their patients. A similar approach using established guidelines can be applied to return-to-work considerations and causation analysis. More details and examples of return-to-work and causation analyses will be featured at the AAOS Workers’ Compensation and Musculoskeletal Injuries Course.

J. Mark Melhorn, MD, FAAOS, is a clinical associate professor of orthopaedics at the University of Kansas School of Medicine in Wichita, Kan.

R. David Bauer, MD, is an orthopaedic surgeon at Orthopedic Independent Medical Examination in Garland, Texas.

Dr. Melhorn and Dr. Bauer are director and faculty for the AAOS Workers’ Compensation and Musculoskeletal Injuries Course.

Rebecca Araujo is the managing editor of AAOS Now. She can be reached at


  1. Melhorn JM, Talmadge JB, Ackerman WE III, Hyman MH: AMA Guides to the Evaluation of Disease and Injury Causation (2nd ed.). American Medical Association Press; 2013.
  2. Social Security Act of 1935, 1 U.S.C. §§1395-1395lll, subchapter XVIII, chapter 7, Title 42. (1965).
  3. Institute for Quality and Efficiency in Health Care: What is evidence-based medicine? Available at: Accessed May 11, 2022.
  4. Harbour R, Miller J. A new system for grading recommendations in evidence-based guidelines. BMJ. 2001;323(7308):334-6.
  5. Wilson CD, Probe RA: Shared decision-making in orthopaedic surgery. J Am Acad Orthop Surg 2020;28(23):e1032-e41.

Registration is now open for the Annual AAOS Workers’ Compensation and Musculoskeletal Injuries Course

The 24th Annual AAOS Workers’ Compensation and Musculoskeletal Injuries Course, Nov. 4 to 6 in San Antonio, Texas, will present effective strategies for utilization review, causation analysis, report writing, medical liability, depositions, and communications skills with patients. During the course, participants will:

  • develop the necessary skills to use the six-step National Institute for Occupational Safety and Health method for determining causation and appropriate medical necessity in orthopaedic care
  • hear from faculty on the most current evidence-based medicine for improving diagnosis, treatment, and outcomes of occupational injuries
  • delve into real-world example cases exploring the current legal, administrative, ethical, and insurance issues in a variety of scenarios
  • establish a network of physicians to support skill development in workers’ compensation or forensic science cases

The course is designed to help participants who want to develop and improve their handling of the medical and nonmedical components of workers’ compensation or forensic science cases. An optional half-day pre-course, AAOS Competency-based Education for Independent Medical Examination (IME) / Qualified Medical Evaluator (QME), will be held on Nov. 3.

For more information or to register for the course, visit