The American Joint Replacement Registry released its 2014 annual report this week, noting a significantly larger portion of women than men received hip and knee replacement or revision procedures.

The group said it received data from 210,000 procedures from 2,247 surgeons at 237 hospitals across the U.S. to use for the report.

“These procedures were performed by more than 2,200 surgeons from 45 states and represented the full range of hospital types and sizes. Patients undergoing arthroplasty were more frequently female than male (56.8% of hips, 61.6% of knees), and the mean age of patients undergoing arthroplasty procedures in this U.S. sample was 67.7 years for hip arthroplasty patients and 66.1 for knee arthroplasty patients. These findings demonstrate that nearly half of these operations are performed in individuals under the age of 65 who are not likely represented in Medicare data sets,” the report states.

Of the 211,721 procedures recorded, primary knee procedures made up 56%, with primary hip procedures clocking in at 34.9%. Revision knee and revision hip procedures made up a meager 4.9% and 3.9%, respectively, of all procedures recorded in the report. Only 0.4% of reported cases were hip resurfacing procedures.

Mean age of hip arthroplasty patients was 67 years, a decrease from 2013’s mean age of 67.6 years, the group reported. The most common diagnosis code for hip arthroplasties was osteoarthritis, which was recorded in 78.4% of cases. Neck femur fractures were the cause of 10.7% of cases.

Of the hip procedures recorded, the vast majority were total hip replacements, at 79.5%, with partial hip replacements and hip revisions at nearly 10% each.

The group reported a total of 8,257 hip revisions out of a total of 82,841 hip arthroplasty procedures of all types, with a revision burden of 10%.

For knee replacements, the mean age was 66.1 years, similar to the previous year’s mean age of 66.7 years. Osteoarthritis was even more prominent among knee replacement procedures, being the tagged cause in 94.7% of all cases recorded.

Most of the procedures were total knee replacements, at 91.8%, with revisions taking up 8.1%, the report states. Knee implants used were mainly posterior stabilized, at 55.6%, with cruciate retaining implants making up 31.7% of all replacements. Unicompartmental knee procedures made up only 4.2% of all cases recorded.

For knee arthroplasties, 10,420 revision procedures were recorded out of a total 128,880 knee procedures. That puts the revision burden slightly lower at 8.1% for knees.