Onlay tibial implants appear to provide superior clinical results in robotic unicompartmental knee arthroplasty.

Abstract

BACKGROUND:

Unicompartmental knee arthroplasty (UKA) is an increasingly popular option for the treatment of single-compartment knee osteoarthritis (OA) in adults. Two options for tibial resurfacing during UKA are (1) all-polyethylene inlays and (2) metal-backed onlays.

QUESTIONS/PURPOSES:

The aim of this study was to determine whether there are any differences in clinical outcomes with inlay versus onlay tibial components.

PATIENTS AND METHODS:

We identified 39 inlays and 45 onlays, with average 2.7- and 2.3-year follow-up, respectively, from a prospective robotic-assisted surgery database. The primary outcome was the Western Ontario and McMaster University Arthritis Index (WOMAC), subcategorized by the pain, stiffness, and function subscores, at 2 years postoperatively. The secondary outcome was the need for secondary or revision surgery.

RESULTS:

Postoperative WOMAC pain score was 3.1 for inlays and 1.6 for onlays (p = 0.03). For 25 inlays and 30 onlays with both preoperative and postoperative WOMAC data, pain score improved from 8.3 to 4.0 for inlays versus from 9.2 to 1.7 for onlays (p = 0.01). Function score improved from 27.5 to 12.5 for inlays versus from 32.1 to 7.3 for onlays (p = 0.03). Four inlays and one onlay required a secondary or revision procedure (p = 0.18).

CONCLUSIONS:

We advise using metal-backed onlays during UKA to improve postoperative clinical outcomes.

• Authors: Brian P Gladnick, Denis Nam, Saker Khamaisy, Sophia Paul, Andrew D Pearle
• Journal: HSS journal : the musculoskeletal journal of Hospital for Special Surgery (HSS J) Vol. 11 Issue 1 Pg. 43-9 (Feb 2015) ISSN: 1556-3316 [Print] United States
• PMID: 25737668 (Publication Type: Journal Article)