Today's News

Friday, February 23, 1996

Cemented total hip replacement improves outcomes in JRA

Cemented total hip replacement reduces pain and improves function for juvenile rheumatoid arthritis (JRA) patients, according to a 10-year follow-up study presented Thursday in scientific paper 44.

However, the procedure should be reserved for only the most severely affected patients who may be unable to walk and whose pain cannot be relieved by other means, said co-author Michael J. Chmell, MD, who presented the study's results.

To examine the long-term durability of cemented total hip arthroplasty for adolescents and young adults with JRA, orthopaedic researchers at the Brigham and Women's Hospital, Boston, reviewed the medical records and radiographs of 33 patients (55 hips), having a minimum 10-year follow-up.

Prior to surgery, 11 patients (21 hips) did not walk - three were bedridden and eight were confined to wheelchairs. Another 16 patients (26 hips) required two crutches to walk; and five patients (9 hips) had to use one cane or crutch to walk.

"At follow-up, 19 patients (32 hips) required no assistive devices," said Dr. Chmell. "All patients' hips were either pain-free (76 percent of hips) or mild to moderately painful (24 percent of hips).

"No patient reported severe activity, restricting pain in the hip and all were improved compared to their preoperative status."

Seven patients (10 hips) utilized two crutches and two patients (4 hips) used one cane or crutch.

Each year, nearly 100,000 children in the United States are diagnosed with this disorder.

Hip involvement in JRA often produces the prime functional impairment in these patients, due to that joint's importance, as well as its effect on the pelvis and lower extremities during walking.

Patients with juvenile rheumatoid arthritis are not necessarily "low demand" patients. "Our results show that the durability of cemented total hip replacement in JRA patients may be inferior to the survivorship of cemented implants documented at 15 to 20 years in adult total hip replacement patients," said Dr. Chmell.

A number of factors are likely to impact on the implant's durability in the JRA patient, including medications, nutritional status, disuse, and the disease itself. In addition, structural bony deformities of JRA may alter the usual magnitude and direction of forces borne by the implant postoperatively.

"JRA patients are adolescents and young adults who have the same demands as other individuals of this age group," said Dr. Chmell. "When they are able to walk, they put high demand on their joint replacement, due to the daily needs of completing an education and starting a career and/or family."

At the time of review, 28 patients retaining at least one component in situ were able to walk outside the home, Dr. Chmell said. Twelve femoral components (18 percent), and 23 acetabular components (35 percent) had been revised at means of 12.8 years and 11.8 years, respectively. Both components remained in situ in 30 hips; and 46 of the 55 hips retained at least one original component.

Follow-up X-rays were available for review in 81 percent of the surviving acetabular and femoral components. Overall failure rate of acetabular components was 44 percent and femoral components was 18 percent at follow-up.

Co-authors of the study with Dr. Chmell are Richard D. Scott, MD, and William H. Thomas, MD, both associate clinical professors of orthopaedic surgery, Harvard Medical School; and 1985 Academy president Clement B. Sledge, MD, chairman, department of orthopaedic surgery, The Brigham and Women's Hospital, Boston.

Dr. Chmell is on staff at Rockford Memorial, St. Anthony, and Swedish-American hospitals, all in Rockford, Ill.

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Last modified 27/September/1996