Symptom Relief May Not Translate to Greater Physical Activity After THA

    A study from Australia has a troubling finding: Patients who underwent primary total hip arthroplasty (THA) at a public hospital in South Australia experienced significant reduction in pain and other symptoms, as well as improvement in walking gait biomechanics, but they did not increase their daily physical activity.

    The researchers said that the findings, published online ahead of print by The Journal of Bone & Joint Surgery, “present a worrying picture that while patients have the opportunity to be more physically active through improvements in functional capacity, their physical behaviors do not change.” They call for additional efforts to help patients achieve a healthy level of physical activity following THA.

    The prospective study included 51 patients with an average age of 66. All procedures were performed using the posterior approach and the same implant type. Prior to the procedure, data were recorded for several patient-reported domains, including hip-related symptoms, function, and quality of life.

    In addition, patients underwent gait analysis and musculoskeletal modeling for in-depth analysis of biomechanics and overall walking performance. They also completed 24-hour physical activity monitoring with use of a wrist-worn accelerometer to track activity. In a subgroup of patients, gait analysis and activity monitoring were repeated at 1 year and 2 years postoperatively.

    At both follow-up times, patients reported improvements in pain and other hip-related symptoms, hip function, and everyday quality of life. Gait analysis showed improvement in almost every aspect of walking biomechanics, including walking speed and step length.

    However, 24-hour activity monitoring showed little or no change in daily physical activity patterns. Both preoperatively and postoperatively, patients were sedentary or asleep for 19.5 hours of the day, on average. This finding remained significant after adjusting for age, body mass index, and occupation.

    In fact, there was evidence that sedentary time increased after THA. The percentage of patients who were sedentary for more than 11 hours per day increased from 25% preoperatively to 31% at 1 year and 41% at 2 years postoperatively. At all assessment points, patients reported that most of their active time was spent in light physical activity.

    Activity monitoring also provided information on the patients’ sleep time and quality. Average sleep time remained the same, at about 9 hours per night. However, sleep efficiency had a year-over-year decline, from 84% preoperatively to 80% at 1 year and 77% at 2 years postoperatively. Less than 85% is considered to be inefficient sleep.

    Consistent with many previous studies, these results show that THA leads to significant and substantial improvements in pain, function, and quality of life. However, the present study shows that despite these improvements, few patients changed their daily physical activity patterns in the 2 years after THA.

    “Evidently, a surgical procedure alone may not enable patients to lead a more physically active lifestyle,” the researchers said.

    Although the researchers could not draw conclusions about the reasons why physical activity did not improve, previous reports have suggested that low activity patterns may become hard-wired after years of physical disability. The researchers suggested that if patients have to wait several years before undergoing THA, they may become used to a more sedentary lifestyle.

    Patients undergoing THA often have accompanying health conditions, such as high blood pressure, obesity, and diabetes, that are best managed with increased physical activity and exercise. The researchers concluded that healthcare providers “must consider a multifaceted model of care, which includes patient education on the importance of reducing sedentary behaviors, and addressing a range of barriers and facilitators to increase physical activity postoperatively.”

    This study was conducted at the University of South Australia, the University of Adelaide, Flinders University, and the Royal Adelaide Hospital in Adelaide, South Australia, Australia.


    Bahl JS, Millar SC, Fraysee F, et al. Changes in 24-hour physical activity patterns and walking gait biomechanics after primary total hip arthroplasty: a 2-year follow-up study. J Bone Joint Surg Am. 2021 May 27. doi: 10.2106/JBJS.20.01679. Online ahead of print.