Gender, number of comorbidities affect risk for THA implant failure

Dislocation, periprosthetic femoral fracture and deep infection were the most common causes for revision up to 6 months after primary THA.

Men have a higher risk of failure following primary total hip arthroplasty, particularly those younger than 60 years of age at the time of surgery and those with a high Charlson comorbidity index score, according to a study by researchers in Denmark.

Søren P. Johnsen, MD, PhD, and colleagues at Aarhus University Hospital and Odense University Hospital reviewed data for all unilateral primary total hip arthroplasty (THA) patients treated from 1995 to 2002 contained in the Danish Hip Arthroplasty Register. The researchers examined associations between possible patient-related predictors of implant failure at three postoperative periods — 0 to 30 days, 31 days to 6 months, and after 6 months.

They published their findings in the British edition of the Journal of Bone and Joint Surgery.

Of 36,984 patient records that met inclusion criteria for the study, 1,132 patients (3.1%) underwent revision.

Up to 30 days postop, revisions were mainly performed due to dislocation, periprosthetic femoral fracture and deep infection. Men had more revisions for dislocation than women, 70% compared to 59%. Additionally, men had an increased adjusted relative risk of 1.5 for failure due to any cause, according to the study.

The researchers also found a tendency towards increased risk of early failure with increasing age and with a high Charlson comorbidity index score. Patients aged 80 years and older had a 1.6 adjusted relative risk for failure, and patients with a high comorbidity index score had a 2.3 adjusted relative failure risk, according to the study.

Dislocation, periprosthetic femoral fracture and deep infection remained the most common causes of revision during the 31 days to 6 months time period. The researchers found no clear differences in failure rates in regards to age or gender, although a high comorbidity index score was associated with a adjusted relative failure risk of 3.0 compared lower comorbidity index scores, according to the study.

During the 6 months and later time period, aseptic loosening represented the most common reason for revision. But: "Male gender remained a predictor for THR failure," the study authors said, noting these patients had a 1.2 adjusted relative failure risk. Also, "In contrast to the second period (31 days to 6 months), younger age appeared to be associated with an increased risk of failure," they said.

Compared to patients aged 60 to 69 years at the time of primary surgery, the adjusted relative failure risk was 1.7 for those aged 10 to 49 years and 1.3 for those aged 50 to 59 years. "In contrast, age between 70 and 79 years and age 80 and over were associated with a reduced adjusted relative risk for failure of 0.9 and 0.6, respectively," the authors said.

Both a medium and high comorbidity index score were associated with an increased risk for late failure. Trauma and avascular necrosis, among other diagnoses, were also associated with increased failure risk from 0 days to 6 months compared to a diagnosis of osteoarthritis, but not after 6 months, according to the study.

For more information:
Johnsen SP, Sørensen HT, Lucht U, et al. Patient-related predictors of implant failure after primary total hip replacement in the initial, short- and long-terms. J Bone Joint Surg Br. 2006;88-B:1303-1308.