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Abstract
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Introduction
Classical knee arthroplasty is subject to different problems that can negatively influence the clinical outcome. Rotational and coronal malalignment, implant overhang and non-anatomic implant design with altered knee kinematics are only some causes discussed in literature. The idea behind customised individually made total knee arthroplasty (CIM TKA) is to avoid such problems and improve clinical outcome. The purpose of this study was to assess the clinical and patient-reported outcome measures (PROMs) of CIM TKA.
Methods
Since January 2017, we prospectively collect PROMs from patients scheduled for a primary cruciate-retaining CIM TKA (iTotal CR, ConforMIS, Inc., Bedford, MA). The surgeon completed the objective Knee Society Score (KSS) before the surgery and after 12 months
We collected the following PROMs before the surgery, after 12 and 24 months: Knee injury and Osteoarthritis Outcome Score (KOOS), Forgotten Joint Score (FJS-12), EuroQol (EQ-5D-3L) and patient satisfaction. We analysed pre-post data with paired t-tests and calculated the proportion of patients whose results improved at least by the minimal important difference (MID).
Results
We analysed data for 70 CIM TKA after 12 months (61 patients, 48% female) and 42 CIM TKA after 24 months (35 patients, 54% female). Mean patient age at surgery was 67 years (SD 8.7, range 48 to 83), mean KSS was 52 points (SD 11.6, range 19 to 85).
Complete follow-up data will be available in June 2021. We present preliminary results of the first 63 CIM TKA (12 months) and 37 CIM TKA (24 months). Mean KSS improved to 94 points (SD 7.9, range 63 to 103, p < 0.001).
All PROMs improved after 12 and 24 months (p < 0.001). The proportion of patients with results above the MID ranged from 69% to 90% after 12 months and from 78% to 92% after 24 months. Most patients were very satisfied or satisfied after the surgery: 86% after 12 months and after 24 months, respectively. Complications occurred in three patients: a quadriceps tendon rupture (after 18 months), an arthrofibrosis that required arthrolysis (after 12 months) and one complete revision (after 18 months).
Conclusion
The data on CIM TKA showed very good clinical and patient-reported results including a high patient satisfaction. Future studies have to confirm these in long-term. It will also be of major interest to investigate, if CIM TKA show better postoperative PROMs in comparison to off-the-shelf implants.
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