Obesity and Hip Replacements

Overweight and obesity are well-established risk factors for osteoarthritis and a major factor in driving the increasing demand for hip and knee replacements.

How does being overweight or obese affect functional outcomes of hip surgery?

This question was addressed by André Busato and colleagues from the Institute for Evaluative Research in Orthopaedic Surgery, University of Berne, Switzerland in a paper just out in Obesity Surgery.

Busato and colleagues quantified the role of high preoperative BMI on long-term pain status and functional outcome after total hip replacements in a multi-center cohort of 20,553 primary hip replacements (18,968 patients) and 43,562 postoperative clinical examinations for a follow-up period of up to 15 years.

Despite equal pain relief in obese and lean patients, there was an almost perfect dose-effect relationship between preoperative BMI and decreased ambulation during the follow-up period.

This means that despite improvement in pain, patients with higher BMIs tend to regain less mobility following the hip replacement.

While the authors suggest that lifestyle management and pre- or post-surgical weight loss will improve outcomes, this has yet to be demonstrated in a large randomized trial.

It may well be that other factors unrelated to pain may be affecting mobility in heavier patients. In fact many factors that may have led to the weight gain in the first place may not be resolved simply by having a hip replacement.

This observation is not different from that of a previous study that I recently blogged on which reported that back surgery for pain relief in patients with spinal stenosis does not automatically result in increased mobility or weight loss.

Obesity is a multifactorial chronic disease and the long-term impact of educational and behavioural interventions is modest at best.

When present, obesity has to be addressed with the same interdisciplinary acumen and persistence as any other chronic disease.

Edmonton, Alberta