Why Isn't My Patient Getting Better? A Functional Medicine Framework for Refractory Pain

We have all been there. You have a patient with a standard orthopedic diagnosis, perhaps chronic low back pain or a stubborn frozen shoulder. You’ve implemented an evidence-based rehab plan, monitored their compliance, and checked all the biomechanical boxes. Yet, by the third or fourth visit, the needle hasn’t moved.

As a physical therapist since 1990 and a registered nurse, I reached a point in my own career where I realized that “typical physical therapy alone” wasn't enough for the patients who remained unresolved. I went into nursing specifically to expand my scope because I saw so many patients who weren't getting better. What I discovered is that for many of our refractory patients, pain is not a life sentence, but a story of systemic imbalance.

Redefining the root cause: the systems biology approach

Functional medicine is more than just a trendy term. It is a shift from symptom suppression to seeking the root cause through systems biology. In a conventional model, physicians often view a knee as just a knee joint. If the knee hurts, we look at pharmaceuticals or procedures that might offer temporary relief but fail to offer long-term resolution.

A functional medicine approach acknowledges that local pain can be influenced by systemic triggers. It requires us to look at how different parts of the body interact, specifically hormones, nutrition, sleep, stress, and gut health. This model is demonstrated to have beneficial and sustainable associations with a patient’s reported health-related quality of life.

The hormonal influence: why pain perception isn't linear

Hormones are powerful regulators of inflammation, tissue repair, and pain perception. When these systems fall out of balance (a frequent occurrence in perimenopausal patients or men with declining testosterone) the body’s pain volume gets turned up, leading to significant hypersensitivity. 

Key hormonal players in pain modulation

• Estrogen: In its optimal range, estrogen supports cartilage health and stabilizes mast cells. When estrogen drops, the body loses its primary chemical “brake” on inflammation. I often describe this as inflammation bubbling up. Without estrogen to suppress inflammatory markers, low-grade systemic inflammation becomes more active, leading to persistent joint and muscle pain. For many women, this musculoskeletal pain is actually a more frequent symptom of menopause than the classic hot flash.² 

• Progesterone: Progesterone is a vital sex hormone that serves a specific calming function for the nervous system while helping to reduce physical swelling and inflammation in the tissues.

• Testosterone and DHEA: These are anabolic hormones that support muscle and joint strength. Testosterone deficiency is directly linked to elevated oxidative stress, which causes cartilage damage and accelerates joint tissue degradation.¹ I’ve seen this manifest as chronic back or hamstring pain in male patients that simply won’t resolve with standard rehab until the deficiency is addressed.

• The cortisol paradox: Cortisol is often maligned as a stress hormone, but it is vital for pain control when it follows a healthy circadian rhythm. In its sweet spot (highest in the morning and lowest at night) it provides an anti-inflammatory effect. However, if it stays excessively high, it becomes catabolic (breaking down tissue), and if it is too low, the body loses its ability to fight systemic inflammation. Both extremes result in increased pain sensitivity. 

• Thyroid: Often overlooked in orthopedic settings, thyroid hormones influence the metabolism of every cell. They provide the cellular energy necessary for muscles and joints to function and repair themselves.

Clinical presentation of hormonal pain

When interviewing your patients, start looking for these hormonal red flags that fall outside of a traditional biomechanical injury:²

• Joint stiffness and widespread aches with no specific traumatic onset.

• Pain that fluctuates or worsens premenstrually or during the menopausal transition.

• Chronic pain that fails to resolve even after a technically successful intervention, such as surgery or physical rehab.

The gut-joint axis: the most overlooked pain trigger

The gut-joint axis is a real, scientifically backed connection where the microbiome influences immune signaling and systemic inflammation.^3,4 The gut microbiome consists of trillions of bacteria that help regulate how our body perceives pain.

The mechanism often involves increased intestinal permeability, traditionally known as leaky gut. The gut lining has tight junctions (think of them as bouncers at a bar) that regulate what enters the bloodstream. When these junctions become weak due to poor nutrition, stress, or dysbiosis (an imbalance of good versus bad bacteria), they allow bacterial endotoxins called lipopolysaccharides (LPS) into the bloodstream.

These endotoxins can migrate through the body and often land in areas that have already been injured or infiltrated by surgery, creating chronic, low-grade inflammation that pushes a patient above their pain threshold. In fact, research suggests that microbiome dysbiosis often precedes the clinical onset of rheumatoid arthritis (RA), playing a significant role in the development of the condition.⁵

We must also consider individual food triggers. Common culprits include gluten, dairy, refined sugar, and processed oils. However, sensitivities are highly individualized. I discovered my own “healthy” morning spinach smoothies were the trigger for my achy hands. Within two weeks of removing that one ingredient, the pain vanished.

Cellular energy, stress, and the sleep cycle

If the engines of the cell (the mitochondria) aren't functioning, the patient cannot heal. Mitochondrial dysfunction is frequently linked to chronic pain, fibromyalgia, and fatigue. It directly impacts cellular resilience and the body’s ability to repair tissue.⁶

• Nutrient deficiencies: Mitochondria require specific nutrients to produce energy. Deficiencies in B vitamins (like B6 or B12) can lead to neuropathy. Low levels of magnesium, Vitamin D, CoQ10, and carnitine can further impair mitochondrial function and contribute to persistent muscle and joint pain.⁷

• Chronic stress and the HPA axis: Chronic stress dysregulates the hypothalamic-pituitary-adrenal (HPA) axis. This disruption alters cortisol rhythms, leading to poor healing and increased inflammatory markers like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α).⁸

• The sleep-pain connection: Poor sleep quality amplifies pain. Circadian disruption leads to nighttime alertness instead of deep, restorative sleep. Without restorative sleep, fatigue, brain fog, and pain symptoms inevitably worsen.⁹

Clinical application: what to ask in a standard visit

As clinicians, we are often the first to hear a patient's story. Because we spend significant time with these individuals during their recovery, we have a unique opportunity to act as clinical detectives. By using motivational interviewing, we can broaden our intake beyond the site of pain to uncover systemic imbalances that may be stalling their progress.

When a patient’s recovery plateaus, the answer rarely lies in doing more of the same biomechanical exercises. Instead, we must look for clues that the patient’s internal environment is preventing tissue repair.

The following table outlines how to translate functional medicine principles into standard clinical questions:

Empowering the patient through data

One of the most effective tools in a functional tool kit is the food diary. Rather than giving a list of “bad” foods, encourage your patients to track patterns between what they consume and how their joints feel over the following 24 to 48 hours.

Often, patients are already aware that certain triggers (like dairy, gluten, or refined sugars) affect them, but they haven't connected those triggers to their orthopedic pain. When you help them make that connection, you move from being a practitioner who “fixes” them to a mentor who empowers them to control their own inflammatory environment.

When to collaborate or refer

You don't have to be a functional medicine expert to help these patients, but you do need to know when to open that door. Consider collaborating with or referring to a functional medicine specialist if:

1. Pain is refractory despite high-quality, evidence-based standard care.

2. Pain flares occur for no apparent reason or traumatic onset.

3. The patient presents with complex hormonal or gut symptoms (for example, menopause, andropause, and irritable bowel syndrome).

4. The patient is struggling with chronic fatigue syndrome or suspected mitochondrial dysfunction.

5. The patient is interested in root-cause approaches and wants to safely manage or reduce medications in conjunction with their provider.

By asking why and looking at the interconnected systems of the body, we can decode the story of our patients' pain and help them find the relief they are looking for.

Conclusion

By shifting our perspective from isolated biomechanics to a systems-based approach, we provide our patients with more than just temporary relief—we offer them a path to long-term vitality. Chronic pain is rarely a single-joint issue; it is the physical manifestation of an internal environment out of balance. As practitioners, our responsibility is to keep asking why, decoding each patient's unique story to uncover the hidden drivers of their dysfunction. When we integrate these functional principles into our clinical reasoning, we don't just treat symptoms; we facilitate true healing. 

If you’re ready to transform your clinical approach to chronic cases, check out my Medbridge course Functional Medicine Foundations for Rehab. This course moves beyond symptom suppression to explore how systemic imbalances (such as hormonal shifts, gut dysbiosis, and mitochondrial dysfunction) drive persistent pain. You’ll gain practical tools to identify when barriers like HPA axis dysregulation or nutrient deficiencies are stalling recovery, allowing you to look beyond the local pain site and collaborate effectively with functional medicine specialists for sustainable patient outcomes. 

References

1. Ma, N., & Gao, F. (2025). Correlation between low testosterone levels and the risk of osteoarthritis: A cross-sectional analysis of NHANES data (2011–2016). BMC Musculoskeletal Disorders, 26(1), 23. https://pmc.ncbi.nlm.nih.gov/articles/PMC11706034/

2. Blumer, J. (2023). Arthralgia of menopause: A retrospective review. Post Reproductive Health, 29(2), 95–97. https://pubmed.ncbi.nlm.nih.gov/37127408/

3. Jeyaraman, M., Ram, P. R., Jeyaraman, N., & Yadav, S. (2023). The gut-joint axis in osteoarthritis. Cureus, 15(11), e48951. https://pmc.ncbi.nlm.nih.gov/articles/PMC10725653/

4. Ustianowska, K., Ustianowski, Ł., Machaj, F., Gorący, A., Rosik, J., Szostak, B., Szostak, J., & Pawlik, A. (2022). The role of the human microbiome in the pathogenesis of pain. International Journal of Molecular Sciences, 23(21), 13267. https://pubmed.ncbi.nlm.nih.gov/36362056/

5. Lin, L., Zhang, K., Xiong, Q., Zhang, J., Cai, B., Huang, Z., Yang, B., Wei, B., Chen, J., & Niu, Q. (2023). Gut microbiota in pre-clinical rheumatoid arthritis: From pathogenesis to preventing progression. Journal of Autoimmunity, 141, 103001. https://pubmed.ncbi.nlm.nih.gov/36931952/

6. van den Ameele, J., Fuge, J., Pitceathly, R. D. S., Berry, S., McIntyre, Z., Hanna, M. G., Lee, M., & Chinnery, P. F. (2020). Chronic pain is common in mitochondrial disease. Neuromuscular Disorders, 30(5), 413–419. https://pubmed.ncbi.nlm.nih.gov/32334903/

7. Alvarez, M., Poveda, S., Cisneros, A., Parra, D., Luna, M., Rincón, O., & Guzman, I. (2026). B vitamin deficiencies and associated neuropathies. Current Nutrition Reports, 15(1), 8. https://pmc.ncbi.nlm.nih.gov/articles/PMC12855320/

8. Hannibal, K. E., & Bishop, M. D. (2014). Chronic stress, cortisol dysfunction, and pain: A psychoneuroendocrine rationale for stress management in pain rehabilitation. Physical Therapy, 94(12), 1816–1825. https://pubmed.ncbi.nlm.nih.gov/25035267/

9. Haack, M., Simpson, N., Sethna, N., Kaur, S., & Mullington, J. (2020). Sleep deficiency and chronic pain: Potential underlying mechanisms and clinical implications. Neuropsychopharmacology, 45(1), 205–216. https://pubmed.ncbi.nlm.nih.gov/31207606/