A new study from UHN’s Toronto General Hospital Research Institute (TGHRI) found that individuals with both knee osteoarthritis (OA) and osteoporosis have distinct characteristics compared to those with only osteoarthritis.
OA is a degenerative, chronic disease that causes joint pain and stiffness, while osteoporosis is a disease that weakens bones, making them fragile and prone to fractures. Little is known about patients who have both conditions.
In the past, researchers thought OA might protect against osteoporosis and vice versa. However, studies exploring this idea have had some limitations. In addition, few studies have specifically examined knee OA disease features and pain origins in individuals with both OA and osteoporosis.
In this study, researchers analyzed whether people with both knee OA and osteoporosis form a unique group compared to those with OA alone. The team examined the prevalence of osteoporosis in a cohort of knee OA participants from the Osteoarthritis Initiative (OAI). They also evaluated subchondral bone—the layer beneath the cartilage in joints—, bone marrow lesions (painful bruising within subchondral bone), and cartilage thickness.
The results showed that at least 15% of participants with knee OA also had osteoporosis. This group exhibited lower subchondral bone density, more porous bone structure, and thinner cartilage compared to patients with only OA.
Interestingly, the researchers found that differences in cartilage were not linked to the degree of pain or symptoms in patients with both OA and osteoporosis. Instead, knee pain in these individuals was more strongly associated with bone issues. Conversely, for people without osteoporosis, cartilage changes were more closely related to symptoms.
The study suggests that osteoporosis may significantly impact knee OA symptoms for some people and that the origin of pain maybe different for these patients. Screening for osteoporosis in knee OA patients could help identify those at higher risk of bone-related pain and damage.
Dr. Andy K. O. Wong, the study’s lead author, is a Scientist at TGHRI and the Schroeder Arthritis Institute. He is also an Assistant Professor in the Epidemiology Division at the Dalla Lana School of Public Health and the Rehabilitation Sciences Institute at the University of Toronto.
This work was supported by the Arthritis Society, Canadian Institutes for Health Research, and UHN Foundation.
Wong AKO, Naraghi AM, Probyn L. Individuals with Knee Osteoarthritis and Osteoporosis Represent a Distinctive Subgroup Whose Symptoms Originate from Differences in Subchondral Bone Rather than Cartilage. Calcif Tissue Int. 2024 Dec 14;116(1):5. doi: 10.1007/s00223-024-01315-z.