A new study has shown that small joint surgeries in rheumatoid arthritis patients — but not large joint surgeries — are on the decline. Researchers aren’t sure why.

A retrospective review of orthopedic surgeries in rheumatoid arthritis (RA) patients has shown that in 2015, less than 1 percent of people with the condition had undergone a small joint surgery.

This percentage is noticeably smaller than it was in 1995.

While researchers took note of this decline in small joint surgeries, they did not see a significant decline in RA patients having larger joint surgeries, such as on the hip or knee.

They did, however, indicate that predictors of large joint surgeries are often easier to spot than predictors indicating the need for a small joint surgery.

The recently published study found that women had a higher incidence of small joint surgeries than men did.

Risk factors for both men and women included advanced age, a positive rheumatoid factor, and a positive anti-cyclic citrullinated peptide lab. These are also indicators of RA risk.

These factors were for both small and large joint surgeries.

Obesity or a high BMI were predictors of the need for large joint surgery among both men and women.

The long-term risk for small joint surgeries, such as on the fingers and wrists, is not as widely known or as understood as the risk factors and predictors for large joint surgery.

The reason why women tend to have more small joint surgeries than men is also not known. It may just boil down to the fact that women seem to have RA more often than men do. Women can also have more severe forms of the condition, including refractory cases of RA.

Despite already having some data, researchers on the recent study wanted to learn more about the incidences of small and large joint surgeries in men and women with RA.

So, they gathered a group that included 1,077 RA patients in the Rochester, Minnesota, area.

The average age was 56 years for both men and woman. About 66 percent of the group had a positive rheumatoid factor with their RA.

Men appeared to have a little more joint swelling than women did, but men and women were similar when it came to obesity, RF positivity, and anti-CCP positivity.

Of the study participants, it was reported that 189 of them underwent at least one joint surgery in the follow-up period. In addition, 90 women and 22 men had one or more small joint surgeries while 141 women and 22 men had one or more large joint surgeries during this interim.

Women seemed to need the surgeries sooner than the men did.

The biggest risk factors for the small joint surgeries seemed to be a positive rheumatoid factor and radiographic erosions. Obesity and steroid use were risk factors for large joint surgeries.

Small joint surgeries appeared to decline for both men and women from the year 2000 on. However, there was no evidence of a trend when it came to large joint surgeries. The rates appeared to stay the same among both women and men during this time period.

It is possible that modern therapies such as disease-modifying antirheumatic drugs (DMARDs) and biologic drugs played a role in lessening the need for surgeries of the smaller joints.

The authors of the study wrote, “longer exposure to DMARDs within the first year after RA diagnosis has also been correlated to a longer time to joint surgery, suggesting that patients derive benefit from early and sustained remission or low disease activity, observations which provide indirect support for the current treat to target strategy.”

They also wrote, “Our findings confirmed that clinical and laboratory markers of severe articular disease are also the risk factors for joint surgery. The higher rate of small joint surgery among women may reflect higher rates of medically refractory disease or predisposition to joint damage compared to men.”

They noted, however, that the study was not without its limitations.

For one, most of the participants were Caucasians. Many were also healthcare workers from the same area.

Additionally, the study relied heavily on medical records — an imperfect science.

Lastly, since the research is retrospective in nature, it might not prove a causal link between disease activity and the need for surgery.