Summary: Knee osteoarthritis (wear-and-tear arthritis) is the most common cause of chronic knee pain. Women are at higher risk. A new study suggests that a certain kneecap shape may be tied to a higher risk of knee osteoarthritis. So early scans may help spot that risk before it shows up later in life.
Osteoarthritis is the most common joint disorder. It often hits the larger joints, especially the knee. It is a leading cause of chronic pain and disability.
Science knows many risk factors. But there is still much to learn. For example, extreme physical stress and injuries might raise the risk. Exercise, on the other hand, may lower it. For example, people with stronger thighs have a lower risk of osteoarthritis.
We also know women are more likely to get it. But the higher risk is not just from hormones or menopause. Other factors are at play.
So science knows many risk factors for one of the most common causes of chronic pain and joint disease. But it still does not know enough. There is no reliable way to predict who will get joint disease or knee pain.
For example, no reliable test can tell if you will get knee pain. It would be great to have reliable markers so people could act early and protect large joints like the knees. That could help prevent osteoarthritis in millions of people.
Kneecap Shape Might Hold the Key to Higher Knee Osteoarthritis Risk
This new study on knee osteoarthritis (OA) shows big differences in kneecap shape between men and women. It may help explain why women often get worse patellofemoral (PF) OA. That is arthritis where the kneecap meets the thigh bone. Women are more likely to have PF OA. It causes pain and limits knee use, especially when bending the knee.
The study looked at 3D models of the patella (kneecap) from CT scans of 164 individuals, both healthy people and people with OA. The findings suggest that differences in kneecap shape between the sexes may help explain why women get PF OA more often.
In women, the groove the kneecap slides in (the trochlear groove) was wider and shallower. That could raise the risk of kneecap cartilage damage and PF OA. This difference in bone shape may load the joint unevenly and raise stress on it. Over time, that may damage bone and cartilage.
The study also showed that men usually have larger kneecaps than women. For example, in the OA group, men had wider and taller kneecaps than women. These differences held in both the healthy and OA groups. That suggests built-in sex differences in kneecap shape.
One key finding was a difference between the sexes in the outer and inner surfaces (facets) of the kneecap.
Healthy men and men with OA had wider outer and inner facets than women. The inner facet was significantly wider in healthy men than in women with OA. This suggests that differences in kneecap structure could be tied to how PF OA starts and gets worse.
The study used a 3D shape-measuring method (geometric morphometrics) to study the kneecap. It gave a detailed look at the kneecap’s three-dimensional structure. The results suggest that differences in kneecap shape could change joint stress and add to OA damage.
The researchers think these shape features, especially on the outer facet, might raise joint stress and cartilage damage. That would help PF OA start and get worse.
This research matters for understanding risks that differ by sex and for building targeted treatments for knee OA. Finding the kneecap shapes tied to higher OA risk could help spot at-risk people earlier.
For people with chronic knee pain, interventional pain management methods and a visit with chronic pain specialists can bring real relief and a better quality of life.
Source:
Wilson, L. A. B., Lynch, J. T., Ménard, J. M., Galvin, C. R., & Smith, P. N. (2024). Sex differences in patellar facet shape among healthy and osteoarthritic cohorts. Osteoarthritis and Cartilage, 0(0). https://doi.org/10.1016/j.joca.2024.06.018
Dr. Gurpreet Singh Padda, MD, MBA, MHP
