The Effect of Body Mass Index on Functional Outcome of Patients With Knee Replacement.
David T Burke, Daniel P Burke, Samir Al-Adawi and 3 others
PMID 33543050WHAT IT FOUND
In 742 patients after knee replacement, higher body mass index was not linked to slower functional recovery in inpatient rehab.
When accounting for age and stay, daily functional gains were higher in obesity classes II and III.
Key findings
01After adjustment for length of stay and age, overall functional change was significantly better for obesity class II and III than normal weight, but not for overweight or obesity class I.
02Motor and cognitive FIM comparisons did not show significant differences between weight groups and normal weight.
03The analysis included only patients referred by surgical teams and accepted for postacute inpatient rehabilitation, so it does not represent all knee replacement patients.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
Only patients referred by surgical teams and accepted for inpatient rehabilitation were analysed, so the findings may not apply to all people who have knee replacement, including those sent home or denied surgery. Referral and admission screening may have favoured higher-BMI patients who showed better acute recovery or motivation, or may have excluded them because of bias. The study is observational and retrospective, so it cannot show that BMI caused the observed functional gains. Adjustments were reported for sex, age, and length of stay, but not for other factors that may influence recovery. The sample came from a setting that may be shrinking because insurance changes moved recovery out of acute rehabilitation hospitals. One underweight patient was excluded, so the study does not describe outcomes for underweight patients.
Declared interests
No funding or conflict-of-interest statement is included. Data were provided by the American Medical Rehabilitation Providers Association and organized by eRehab.
The easy way to misread this
Do not read the higher adjusted gains in obesity classes II and III as proof that obesity improves recovery after knee replacement. The study was observational and only included patients accepted for inpatient rehabilitation, and the motor and cognitive subscores did not show significant differences.