Preoperative Functional Status Impacts Outcomes of Total Hip Arthroplasty

Patients who were functionally dependent on another caregiver prior to surgery were more likely to experience adverse perioperative outcomes following total hip arthroplasty, according to a recent study.

The study, presented today at the 2019 Annual Meeting of the American Association of Orthopaedic Surgeons (AAOS) in Las Vegas, evaluated the impact of preoperative functional status on surgical outcomes, including operative time, hospital length of stay, discharge disposition, readmissions, reoperations, 30-day complication rates and mortality.

“For the right patients, THA significantly relieves pain, increases stability and function, and improves quality of life,” notes Carlos Higuera-Rueda, MD, Chair of the Levitetz Department of Orthopaedic Surgery at Cleveland Clinic Florida – Weston. “Patient selection is key here.”

Functional dependency correlates with adverse surgical outcomes

Dependent functional status has been correlated with adverse 30-day outcomes in other surgical procedures as well, including bariatric surgery, infrainguinal bypass, lower extremity bypass and ventral hernia repair. This study sought to evaluate the impact of preoperative functional status on short-term outcomes following total hip arthroplasty.

Using National Surgical Quality Improvement Program data from the American College of Surgeons, this retrospective review analyzed found that preoperative functional status has significant associations with morbidity and mortality. Patients undergoing elective, unilateral THA with a known preoperative functional status were included in this study (n=155,590).

Preoperative status determined by the patient’s ability to perform activities of daily living (ADLs). Patients were considered to have independent functional status if they were able to perform ADLs preoperatively (n=113,436). Patients who required assistance with ADLs prior to surgery were categorized with dependent functional status (n=2,154).

The analysis indicates that patients who were functionally dependent prior to surgery were more likely to have operative times over 120 minutes, hospital stays of more than 10 days and be discharged to an extended care facility. Dependent functional status was also an independent risk factor for several other complications, readmission, reoperation and increased mortality.

Patients with dependent status have longer hospital stays and higher mortality rates

The researchers have calculated odds ratios (OR) for perioperative outcomes and 30-day complications in patients who require help with their ADLs. Dependent patients were three times [OR 3.01, 95% confidence interval (CI) 1.32-6.87] more likely to be placed on a ventilator for more than 48 hours following surgery, and nearly three times more likely to have a length of stay that exceeds 10 days (OR 2.96, 95% CI 2.09-4.18). They were nearly four times (OR 3.94, 95% CI 1.63-9.57) more likely to develop acute renal failure necessitating dialysis and two times more likely to develop systemic sepsis (OR 2.38, 95% CI1.43-3.99) and progressive renal insufficiency (OR 2.32, CI1.05-5.12). Dependent patients were three times (OR 3.00, 95% CI 1.58-5.66) more likely to die in the post-operative period than patients with independent status.

“These are significant factors that contribute to a much higher mortality rate among dependent patients,” states Dr. Higuera-Rueda. “This study can be used to inform patient counseling and treatment planning, with the goal to get patients as independent as possible prior to surgery. Additionally, dependent functional status should be used for risk stratification for quality metrics and reimbursement purposes.”

Osteoarthritis is the most common indication for THA, and there are more than 300,000 THAs performed in the United States each year. In 2017, the mean age for THA was 65.5 years, according to the American Joint Replacement Registry’s 2018 annual report.