Total Hip Arthroplasty in the Underweight

The outcomes of 20 patients diagnosed with osteoarthritis or rheumatoid arthritis with body mass index less than 18.5 (considered underweight) who received total hip arthroplasty at a single institution were reviewed. Surgical complications in the first 30 days after surgery included 1 prolonged surgical site drainage and 3 posterior dislocations. Two patients experienced medical complications that included hematemesis, confusion, aspiration pneumonia, and death. Sixty-five percent of the patients received at least one blood transfusion. Harris hip scores improved from 35 to 81 (P < .05) at an average of 6.1 years (2-10.1 years) of follow-up. Total hip arthroplasty is effective in patients who are underweight; however, they appear to be at an increased risk of dislocation and blood transfusion.