Is a short stem an option for obese patients?

Background: Obesity is a significant risk factor for hip osteoarthritis due to increased mechanical loading and adipokine-mediated cartilage inflammation. While short-stem femoral components in total hip arthroplasty (THA) offer bone preservation and facilitate minimally invasive approaches, concerns persist regarding their primary stability and potential for increased migration in patients with high body mass index (BMI).

Objective: This study evaluates the clinical and radiological outcomes of a specific short-stem femoral prosthesis in obese patients to determine if increased body weight or BMI adversely affects implant stability and patient satisfaction.

Key Points: Analysis of 483 patients divided by BMI categories (<25, 25–30, and >30 kg/m²) and 773 patients divided by weight (<100 and >100 kg) revealed no statistically significant differences in implant subsidence or clinical outcomes at 24 months. Although minor initial subsidence (up to 6 mm) occurred within the first three months due to undersizing and learning curve effects, secondary stabilization was achieved in all groups. Obese patients demonstrated higher rates of systemic and wound healing complications, yet reported comparable improvements in Visual Analog Scale (VAS) pain scores. While Harris Hip Scores were slightly lower in the obese cohort (94.4 vs. 97.7), this was attributed to general physical restrictions rather than implant failure. Literature suggests absolute body weight may influence long-term survivorship more than BMI, particularly in patients exceeding 80 kg.

Conclusion: Short-stem femoral components demonstrate comparable stability and clinical efficacy in obese and non-obese populations. Despite higher perioperative risks, obesity is not a contraindication for short-stem THA, provided optimal component sizing and press-fit fixation are achieved.