A landmark study provides objective proof that onychectomy, a procedure often performed for convenience, rewires a cat’s nervous system for chronic pain, leading to heightened sensitivity and lifelong impairment.
For decades, a fierce debate has raged in the veterinary world and among cat owners about feline onychectomy, or declawing. Proponents have argued it’s a necessary evil to prevent household damage or injury, a last resort to keep a cat in its home. Opponents have condemned it as a cruel and unnecessary amputation. While the procedure is banned in most of Western Europe and Canada, it remains legal and relatively common in the United States. For years, the discussion has been clouded by a lack of objective, long-term data, with many claims of harm being anecdotal or difficult to separate from other age-related ailments like osteoarthritis (OA).
Now, a comprehensive new study cuts through the ambiguity with compelling scientific evidence. Researchers from the Groupe de recherche en pharmacologie animale du Québec (GREPAQ) conducted a secondary analysis of data from eight studies spanning over a decade, providing one of the most robust examinations to date of the long-term consequences of declawing. Their findings, published in Scientific Reports, are unequivocal: declawing is associated with chronic pain, maladaptive neuroplasticity—a rewiring of the nervous system for pain—and significant functional impairment that goes far beyond the pain of OA alone.
Seeing the Unseen Pain
One of the greatest challenges in veterinary medicine is that our patients cannot tell us where it hurts. This is especially true for cats, who are masters at hiding pain and discomfort. To overcome this, the research team employed a suite of validated, objective tools to measure pain and mobility in three distinct groups of cats: healthy, non-declawed cats (HC), non-declawed cats with osteoarthritis (NDOA), and declawed cats with osteoarthritis (DOA).
Instead of relying on subjective observation alone, the scientists used advanced techniques:
- Quantitative Sensory Testing (QST): This involves applying precise, calibrated stimuli to a cat’s paws to measure their pain threshold. By recording the exact force at which a cat withdraws its paw (Paw Withdrawal Threshold, or PWT), researchers can quantify hypersensitivity.
- Podobarometric Gait Analysis (PGA): Cats were trained to walk across a pressure-sensitive mat that created a detailed map of how they distribute their weight with every step. This reveals subtle limping or weight-shifting that might be invisible to the naked eye.
- Standardized Mobility Assessment: A validated scale, the Montreal Instrument for Cat Arthritis Testing (MI-CAT(V)), was used to score functional impairment during standardized tasks.
- Nerve Conduction Studies: In a subgroup of cats, the researchers directly measured the electrical signals traveling through the nerves in their limbs, looking for evidence of physical damage.
The Damning Evidence
When the data from these rigorous tests were analyzed, a clear and disturbing picture emerged. Declawed cats weren’t just in pain; their entire sensory system appeared to have been altered by the procedure.
First, the declawed cats with OA (DOA group) were significantly more sensitive to pain than their non-declawed counterparts with OA. They withdrew their paws from much lighter touches, a classic sign of hyperalgesia. More than half (57.9%) of the declawed cats met the criteria for allodynia—a condition where a normally non-painful stimulus, like a gentle touch, is perceived as painful. This suggests their nervous systems are in a constant state of high alert.
Second, the declawed cats showed greater functional impairment. They scored significantly worse on the mobility scale, indicating more difficulty with everyday movements. The gait analysis revealed a particularly telling detail: while heavier cats in all groups put more force on their limbs, this effect was distorted in declawed cats. For them, extra body weight disproportionately worsened their biomechanical dysfunction, suggesting their altered paws are less able to cope with normal physical stresses.
Perhaps the most groundbreaking finding came from the nerve conduction studies. This is where the science provides a potential “smoking gun” for why declawing causes such lasting problems. The electrical signal traveling through the main motor nerve in the hindlimbs of declawed cats was significantly weaker than in non-declawed cats. This decreased signal amplitude is indicative of axonal loss—physical damage to the nerve fibers themselves.
This finding aligns the pain of declawing with post-amputation pain syndromes in humans. The transection of nerves during the amputation of the final toe bone can lead to the formation of neuromas (painful nerve endings) and, as this study shows, long-term nerve damage that contributes to a chronic neuropathic pain state.
A Vicious Cycle of Pain
The study’s results strongly suggest that onychectomy induces maladaptive neuroplasticity. The intense, noxious stimuli from the surgery can trigger a long-term potentiation of pain pathways in the spinal cord and brain. In essence, the nervous system “learns” the pain and becomes more efficient at signaling it, creating a self-sustaining cycle of chronic pain that persists for years, long after the surgical wounds have healed.
This has profound implications for managing pain in these animals. The study notes that the type of sensitization seen in declawed cats often responds poorly to standard pain medications like NSAIDs, which are the cornerstone of OA treatment. This means that declawed cats are not only in more pain, but their pain is also harder to treat effectively.
Importantly, the researchers found no significant difference in pain or impairment between cats declawed on two paws versus four, or between those with or without remnant bone fragments left behind from the surgery. While poor surgical technique can certainly make things worse, the study suggests that the damage is inherent to the procedure itself, regardless of how well it is performed.
A Call for a Worldwide Ban
This study moves the conversation about declawing from the realm of ethics and opinion into the domain of scientific fact. It provides robust, objective evidence that onychectomy is not a benign “fix” but a procedure that causes lasting harm, exacerbating pain, inducing nerve damage, and compromising a cat’s quality of life.
Given that declawing is an elective procedure performed for owner convenience, not for the cat’s medical benefit, these findings make the ethical justification for it untenable. The authors conclude with a clear call to action: veterinary professionals must educate owners about the severe consequences and advocate for humane alternatives like scratching posts, nail caps, and regular nail trimming. They urge regulatory bodies to use this scientific evidence to enact a universal ban on declawing, recognizing it as an ethically unacceptable intervention with devastating, lifelong consequences for cats.
Reference
Lefort-Holguin, M., et al. (2025). Declawing in Cat is associated with neuroplastic sensitization and long-term painful afflictions. Scientific Reports. https://doi.org/10.1038/s41598-025-16288-8
