Abstract
PurposeCustomized 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.MethodsFifty-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.ResultsOverall, 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%)].ConclusionCIM-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 evidenceIV.
Highlights
Osteoarthritis (OA) of the knee is one of the most common diseases that cause pain and dysfunction [17] and affects many health outcomes [16]
For the treatment of OA, total knee arthroplasty (TKA) is the standard of care that provides high reproducibility of outcomes except in young patients where the failure rate is higher, and patient satisfaction and improvement are lower than older patients [10, 18, 26, 29]
Substantial improvement in clinical outcomes is reported after TKA in young patients, increased risks of failure rates, less improvement, and dissatisfaction after TKA in those young and early OA patients have been shown [10, 26]
Summary
Osteoarthritis (OA) of the knee is one of the most common diseases that cause pain and dysfunction [17] and affects many health outcomes [16]. Customized Individually Made (CIM) BKA implants (ConforMIS Inc, Burlington, MA) and three-dimensional printed customized surgical instruments are currently available to fit to each patient’s unique anatomy, medial and patellofemoral, or lateral and patellofemoral Unique to this implant is that it resurfaces the 3 mm of cartilage on the subchondral bone with a 3-mm-thick implant and only removes a 3–5-mm anterior and posterior femoral cut to implant the prosthesis. A bicompartmental monolithic implant, made from a standard prosthesis less a condyle using standardized faceted 10 mm cuts, has been available in the past but taken off the market because of poor outcomes due to impingement and fit issues These occurred at the patellofemoral native compartment junction as well as tibial baseplate fractures resulting in a high failure rate of up to 60% at a minimum follow-up of 54 months [8, 22]. The hypothesis in this study was that a significant improvement in pain and function with a high level of satisfaction would be provided after CIM-BKA while preserving the cruciates and bone stock
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