JOA - 2026-05-13 - Journal Article
Cementless Total Knee Arthroplasty in the Morbidly Obese Patient Using a Highly Porous Tibial Baseplate: Minimum 10-Year Follow-Up.
Nadar AC, Gul E, Smith LS, Henningsen J, Lustig S, Yakkanti MR, Malkani AL
Topics
Key Takeaway
Cementless TKA with a highly porous tibial baseplate achieved 97.8% survivorship free of aseptic loosening at 12 years in morbidly obese patients (mean BMI 46.1), with only 2 tibial aseptic loosening events both occurring within 8 months of index surgery.
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Summary
This retrospective study evaluated 10-year outcomes of cementless TKA using a highly porous tibial baseplate in morbidly obese patients (BMI ≥39.5). Of 114 index procedures, 89 TKAs in 74 patients reached minimum 10-year follow-up; 9 total revisions occurred, with aseptic tibial loosening in only 2 cases (2.3%), both within 8 months postoperatively. KSS improved from 36.2 preoperatively to 90.4 at 10 years, and all-cause revision survivorship was 89.9% at 12 years.
Key Limitation
The 22% loss to follow-up in a single-center retrospective series without a concurrent cemented control group prevents definitive conclusions about superiority over cemented fixation in morbidly obese patients.
Original Abstract
BACKGROUND
Morbidly obese patients undergoing cemented primary total knee arthroplasty (TKA) have demonstrated higher revision incidence. Cementless TKA implants have demonstrated good five-year results in this patient population. The purpose of this study was to review 10-year results of primary TKA in morbidly obese (body mass index [BMI] ≥ 39.5) patients using a highly porous, cementless tibial baseplate.
METHODS
This is a retrospective study of 114 TKAs in morbidly obese patients who underwent primary cementless TKA with a minimum 10-year follow-up. There were 25 lost to follow-up, leaving 89 TKAs in 74 patients who had a mean follow-up of 124.7 months (range, 116.9 to 141.9). The average age was 57 years (range, 36 to 73), and the average BMI was 46.1 (range, 39.5 to 63.9). Clinical results, patient-reported outcome measures, radiographs, and complications were reviewed.
RESULTS
There were nine revisions, including two for tibial component aseptic loosening (2.3%), two for instability (2.3%), two for deep infection (2.3%), two for extensor mechanism rupture (2.3%), and one for patellar dislocation (1.1%). The two aseptic loosening cases occurred within eight months of the index TKA. Knee Society Score (KSS) improved from a mean of 36.2 to 88.3, 86.5, and 90.4 at 2-, 5-, and 10-year follow-up, respectively. The KSS function score improved from a mean of 41.5 to 68.7, 75.3, and 80.4 at 2-, 5-, and 10-year follow-up, respectively. Survivorship was 97.8% with aseptic loosening as the endpoint at 12 years and 89.9% for all-cause revision.
CONCLUSION
Cementless TKA using a highly porous tibial baseplate in morbidly obese patients demonstrated excellent results with 97.8% survivorship at 12 years with aseptic loosening as the endpoint. Cementless TKA with the benefit of at least 10 years of biologic fixation can be an alternative mode of fixation compared to cement fixation in this challenging patient population.