Custom TKA combined with personalised coronal alignment yield improvements that exceed KSS substantial clinical benefits

Abstract

Purpose The purpose of this study was to report Knee Society Scores (KSS) at 12-month follow-up in a series of 266 knees that received custom TKA. The hypothesis was that custom TKA combined with personalised alignment would yield improvements greater than substantial clinical beneits (SCB) of KSS Knee and Function. Methods From a consecutive series of 905 patients (918 knees) that received primary TKAs, 261 (29%) patients (266 knees) received computed tomography (CT)-based posterior-stabilised cemented custom TKA. Knees were aligned aiming to preserve or restore constitutional alignment within predetermined limits of 85°-95° for femoral mechanical angle (FMA) and tibial mechanical angle (TMA), and 175°-183° for hip knee ankle (HKA) angle. The KSS Knee and Function were collected preoperatively and 12 months postoperatively, to determine if patients achieved SCB. Uni-and multivariable analyses were performed to determine associations between KSS scores (Knee and Function) and patient demographics as well as pre-and postoperative radiographic alignments. Results Of the initial cohort of 261 patients, 4 (1.8%) were reoperated for patellar resurfacing, 1 (0.4%) for lavage to treat infection, and 1 (0.4%) had arthroscopy to treat a stif knee with < 90° range of motion. Complete clinical records were available for 227 patients (232 knees, 87%) that comprised 102 men (5 bilateral) and 125 women. At 12-month follow-up, mean improvements in KSS Knee and Function scores were, respectively, 61.0 ± 13.0 and 42.7 ± 16.7, which exceeded the SCB of KSS. Comparison of knees inside versus outside the target zone revealed no diferences in KSS Knee (94.1 ± 9.1 versus 94.3 ± 9.0, n.s.) and Function (96.1 ± 9.2 versus 96.3 ± 8.9, n.s.). Multivariable analysis revealed worse KSS Knee in knees with preoperative FMA > 95° (β = − 6.21; p = 0.023), but no association between KSS Function and patient demographics or pre-and postoperative radiographic alignments. Conclusions Custom TKA combined with personalised alignment yielded improvements that exceeded substantial clinical beneits of KSS Knee and Function scores. These indings demonstrate the feasibility of custom TKA with 'personalised alignment' and encourage further investigations using comparative studies at longer follow-up. Level of evidence IV, case series.

Patient Specific Instruments and Patient Individual Implants—A Narrative Review

“…Furthermore, there are three recent comparative studies on the products of both companies, which are mostly not included in meta-analyses. They show clear advantages of CMI compared to off-the shelf implants in terms of pain, mobility, overall outcome, and satisfaction for Conformis (iTotal ® ) [ 38 , 39 , 40 ] as well as Symbios (Origin ® ), with also very promising clinical and radiological results [ 41 , 42 , 43 ]. The latter comparative studies, however, might have conflicting bias as they are at least partly sponsored.…”

Satisfaction after total knee arthroplasty: a prospective matched‐pair analysis of patients with customised individually made and off‐the‐shelf implants

“…As of 2018, another CIM TKA system is available, the Symbios Origin ® implant (Symbios, Yverdon-les-Bains, Switzerland) [ 43 ]. After promising first results [ 44 ], a large improvement in the KSS was recently shown, with a mean KSS of 94 points after 1 year [ 45 ]. Another study reported a high satisfaction rate of 94% after a mean follow-up of 2.8 years [ 46 ].…”

Improved Knee Function with Customized vs. Off-the-Shelf TKA Implants—Results of a Single-Surgeon, Single-Center, Single-Blinded Study

“…Several recent studies were not yet included, though [ 29 , 30 , 31 ]. Recent first studies with customized TKA of a second company with also partial constitutional alignment show promising results as well [ 35 , 36 , 37 ].…”