, Volume 471, Issue 11, pp 3523-3530
Date: 10 Jul 2013

Bariatric Orthopaedics: Total Knee Arthroplasty in Super-obese Patients (BMI > 50 kg/m2). Survivorship and Complications

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Topic
Knee

Abstract

Background

Some studies have suggested that patients who are super obese (BMI > 50 kg/m2) may have poorer outcomes and more frequent complications when undergoing TKA compared with those who have lower BMI, however, the literature on this is scant.

Questions/purposes

The purpose of this study was to compare a group of super-obese patients undergoing TKA with a matched group of patients with BMI less than 30 kg/m2 in terms of (1) implant survivorship, (2) complications, (3) functional parameters, and (4) intraoperative variables (including operative time and estimated blood loss).

Methods

One-hundred one knees in 95 patients (21 men, 74 women) who had a minimum BMI of 50 kg/m2 and who had undergone a primary TKA at one of the four high-volume institutions were compared with a group of patients who had a BMI less than 30 kg/m2 who were matched by age, gender, preoperative clinical scores, and mean followup. End points evaluated by chart review included implant survivorship, medical and surgical complications, functional parameters (The Knee Society outcome scores and ROM), and intraoperative variables at a mean followup of 62 months (range, 36–85 months).

Results

With the numbers available, there were no differences in aseptic implant survivorship (94% versus 98%, p = 0.28), however, medical and surgical complication rates (14% versus 5%, OR: 3.1, 95% CI=1.07–8.9; p = 0.037) were significantly higher in the super-obese patients compared with the nonobese matching group, respectively. Super-obese patients also achieved lower mean Knee Society functional scores (82 versus 90 points, p = 0.004) and smaller gains in flexion arc ROM (14° versus 21°, p = 0.009); they also lost more blood during surgery and experienced longer surgical anesthesia times compared with the matched group, respectively.

Conclusions

With the numbers available, we could not identify what might have been modest differences in implant survivorship, however, complications were more frequent and functional outcomes were significantly lower in super-obese patients. Other studies similarly have found inferior outcomes in this challenging group of patients. Our data may be considered pilot data for future prospective studies with longer followup.

Level of Evidence

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The institution of one or more of the authors has received or will receive, during the study period, funding from Stryker Orthopaedics (Mahwah, NJ, USA) (ALM, SFH, PMB, MAM), TissueGene (Rockville, MD, USA) (ALM, MAM), Sage Products LLC (Cary, IL, USA) (MAM), Wright Medical Technology, Inc (Arlington, TN, USA) (MAM), Biocomposites Inc (Wilmington, NC,USA), Jannsen, Inc (Toronto, ON, CA) (MAM), Joint Active Systems, Inc (Effingham, IL, USA)(MAM), Medtronic, Inc (Minneapolis, MN, USA) (MAM).
One of the authors certifies that he (MAM) has received or may receive payments, during the study period, an amount of USD 100,000 to 1,000,000 from Stryker Orthopaedics (Mahwah, NJ, USA), an amount of USD 10,000 to 100,000 from Wright Medical Technology, Inc (Arlington, TN, USA), an amount of USD 10,000 to 100,000 from Biocomposites Inc (Wilmington, NC,USA), an amount of USD 10,000 to 100,000 from Jannsen, Inc (Toronto, ON, CA), an amount of USD 10,000 to 100,000 from Joint Active Systems, Inc (Effingham, IL, USA), an amount of USD 10,000 to 100,000 from Medtronic, Inc (Minneapolis, MN, USA), an amount of USD 10,000 to100,000 from Sage Products LLC (Cary, IL, USA), and an amount of USD 10,000 to 100,000 from TissueGene (Rockville, MD, USA).
One of the authors certifies that he (ALM) has received or may receive payments, during the study period, an amount of USD 10,000 to 100,000 from Stryker Orthopaedics (Mahwah, NJ, USA), an amount of USD 10,000 to 100,000 from Synthes (Raynham, MA, USA).
One of the authors certifies that he (PMB) has received or may receive payments, during the study period, an amount of USD 10,000 to 100,000 from Stryker Orthopaedics (Mahwah, NJ, USA).
One of the authors certifies that he (SFH) has received or may receive payments, during the study period, an amount of USD 10,000 to 100,000 from Stryker Orthopaedics (Mahwah, NJ, USA).
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request.
Clinical Orthopaedics and Related Research neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA-approval status, of any drug or device prior to clinical use.
Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research.
This work was performed at Sinai Hospital of Baltimore, Baltimore, MD, USA; the University of Louisville, Louisville, KY, USA; Bonutti Clinic, Effingham, IL, USA; and Beth Israel Hospital, New York, NY, USA.
A comment to this article is available at http://dx.doi.org/10.1007/s11999-013-3221-2.