Excess weight ups risk of complications after joint replacement surgery

A study has found that obese patients, who are undergoing shoulder joint replacement surgery, are at increased risk of complications, including the need for 'revision' surgery.

According to researchers, among patients with a BMI of 35 or higher, each additional one-unit increase in BMI was associated with a five percent increase in the risk of re-operation for any reason.

Higher BMI was also specifically associated with revision surgery for mechanical failure.

For every one-unit increase in BMI after 30, there was a five percent increased risk of revision for mechanical failure.

Researcher Eric R. Wagner from the Mayo Clinic, Rochester, Minnesota said that increasing BMI is strongly associated with increased rates of revision surgical procedures and postoperative complications after shoulder joint replacement surgery - arthroplasty.

Their findings suggest that, above a certain level of obesity, complication risk increases steadily along with increasing body mass index (BMI).

Complication risks increase steadily with higher BMI.

The team included 4,567 shoulder arthroplasties performed between 1970 and 2013.

Various shoulder arthroplasty procedures are performed to treat shoulder pain and loss of function resulting from arthritis or other conditions.

The findings suggested that 43 percent of the shoulder arthroplasty patients were obese (defined as a BMI of 30 or higher).

The researchers analysed the relationship between BMI and different types of complications.

Overall, 302 patients needed revision surgery due to mechanical failure, loosening of the implant or other causes.

An additional 62 cases required a non-revision reoperation.

The BMI-related increases in complications remained significant after statistical adjustment for other factors.

The strongest association was for superficial wound infection: risk increased by nine percent for each one-unit increase in BMI.

The results suggested that the risk of revision surgery and most other complications of shoulder arthroplasty increases along with BMI in obese patients.

"These findings support the notion that increasing BMI increases the stress on the implant, leading to higher rates of mechanical implant failure," the researchers wrote.

The study is published in the Journal of Bone and Joint Surgery.