ePoster #720 - ISHA Annual Scientific Meeting 2016
How Body Mass Index Affects Outcomes Following Hip Arthroscopy for Femoroacetabular Impingement.
Timothy Leroux, MD, Chicago, IL UNITED STATES
Benjamin Kuhns, MD, Chicago, IL UNITED STATES
Bryce Basques, MD, Chicago, IL UNITED STATES
Jennifer Alter, BS, Chicago, IL UNITED STATES
Richard C. Mather, MD, MBA, Durham, NC UNITED STATES
Michael Jonathan Salata, MD, Cleveland, OH UNITED STATES
Shane J. Nho, MD, MS, Chicago, IL UNITED STATES
Gift C. Ukwuani, MD, Chicago, IL UNITED STATES
Rush University Medical Center, Chicago, Illinois, UNITED STATES
FDA Status Not Applicable
Summary: We present data assessing how BMI affects two year outcomes following hip arthroscopy.
With improvements in hip arthroscopy technique and instrumentation, indications are expanding to include patients with a wide range of body mass index (BMI). It remains unknown how variations in BMI, including the extremes of low and high BMI, influence outcomes following hip arthroscopy. In this study, we subdivided a cohort of patients undergoing hip arthroscopy according to commonly accepted ranges of BMI and compared outcomes following hip arthroscopy between these subgroups and patients with normal BMI.
A clinical repository containing patients undergoing primary hip arthroscopy for femoroacetabular impingement (FAI) between January 1, 2012 and January 1, 2014 with a minimum follow up of two years was queried to include patients in this study. The primary outcome measure was the Hip Outcome Score Activities of Daily Living (HOS-ADL) questionnaire. A Patient Acceptable Symptomatic State (PASS) cutoff of 87 was used to determine a clinically significant improvement. Secondary outcome measures included the Hip Outcome Score Sports Subscale (HOS-SS) and modified Harris Hip Score (HHS). Included patients were segregated according to their preoperative BMI into one of the following categories: underweight (BMI<18.5), normal (BMI 18.5-24.9), overweight (25-29.9), obese (30-35), and morbidly obese (>35). A multivariate logistic regression model controlling for patient demographics (age, sex) comorbidities, disease severity (tonnis grade, center edge angle, alpha angle, pincer size, cam size), dysplasia (cross-over sign), and pre-operative function (range of motion) was used to identify independent associations between BMI categories and each outcome measure.
The repository contained 494 patients that underwent hip arthroscopy for FAI with a minimum two year follow up on 400 patients (81%). There were 12 patients in the underweight category, 262 in the normal category, 153 in the overweight category, 47 in the obese category and 20 in the morbidly obese category. In the univariate analysis, patients with normal BMI had significantly higher HOS-ADL scores than overweight (88.8 ± 13.9 vs. 84.1 ± 16.7 p=0.009), obese (88.8 ± 13.9 vs. 78.8 ± 19.7 p=0.0009) and morbidly obese patients (88.8 ± 13.9 vs. 73.7 ± 24.7 p=0.001). Furthermore, 69% of patients in the normal BMI group met the PASS cutoff, which was significantly higher than the proportion of patients in the overweight (55%, p=0.0081) and obese (48%, p=0.03) groups. In the multivariate analysis, the only significant difference was that underweight patients had a significantly lower improvement in their HOS-ADL scores as compared to patients with normal BMI (20.0 ± 17.4 vs. 9.7 ± 11.6 p=0.049), and only overweight patients had significantly fewer patients that met the PASS cutoff as compared to patients with normal BMI (75.6% vs. 60.8%, p=0.005).
Overall, we observed that BMI has little influence on the long term outcomes following hip arthroscopy, and supports that notion that all patients, irrespective of BMI, should be counseled that they can expect long term improvements in both pain and function following hip arthroscopy. Future studies should focus on identifying the reasons for the small, albeit significant differences between underweight and slightly overweight patients as compared to patients with normal BMIs.