A high level of satisfaction after bicompartmental individualized knee arthroplasty with patient-specific implants and instruments

Abstract

Purpose: Customized Individually Made (CIM) Bicompartmental Knee Arthroplasty (BKA) implants and three-dimensional printed customized instruments are available to fit to each patient’s unique anatomy, medial or lateral with patellofemoral. This study aimed to evaluate the clinical outcomes after CIM-BKA. Methods: Fifty-five patients [59 knees; average age, 51 years; standard deviation (SD), 6.8; range 37–65 years] who underwent CIM-BKA were evaluated over an average of 3.8-year follow-up (SD 1.6; range 1–6 years). Forty-one knees underwent BKA combined medial and patellofemoral replacement (BKA-MP) and 18 knees underwent BKA combined lateral with patellofemoral replacement (BKA-LP). Survival rates, the modified Cincinnati Knee Rating Scale, WOMAC, VAS, SF-36, a satisfaction survey, and radiographic evaluation were used to evaluate outcomes. Results: Overall, survival rates were 98% and 92% at 2 and 5 years, respectively. Of 56 knees (95%) that did not fail, all patient-reported functional scores significantly improved post-operatively (P < 0.01), regardless of the previous surgeries, with a high level of satisfaction (51/56 knees, 91%). Radiographically, all the femoral components fit perfectly and 56 knees (95%) of the tibial components fit with less than 2 mm of undercoverage or overhang. Three knees (5%) required the conversion to TKA and 17 knees (29%) required subsequent surgical procedures, of which multiply operated knees had higher rate than virgin knee [14/40 (35%) vs. 3/16 (19%)]. Conclusion: CIM-BKA allowed precise fit of the components and provided a significant improvement post-operatively with a high level of satisfaction over short- to mid-term follow-up. This novel CIM-BKA is resurfacing, and does not require 10-mm faceted cuts, being only 3-mm-thick, which preserves bone stock for the future. It may be a promising option for relatively young active patients with bicompartmental osteoarthritis with a longer term follow-up being necessary. Level of evidence: IV.