This was a retrospective cohort study on prospectively collected data of a sample of consecutive patients undergoing total knee arthroplasty due to end-stage osteoarthritis unresponsive to conservative treatments at a single facility by a fellowship-trained joint reconstructive surgeon. The study period was between June 2018 and March 2021. Institutional Review Board (IRB) exemption was obtained prior to study initiation. Waiver of informed consent was issued by the same IRB. There were 89 patients (121 knees) treated with 1G and 98 patients (123 knees) treated with 2G who consented to be enrolled for the study. The surgeon switched from 1G to 2G prostheses once the new implants were available to order. No changes in patient selection strategies were made once the new generations were implanted. Patients were excluded from the study if they had a history of metabolic bone disease (such as Paget’s disease of bone, severe osteoporosis), systemic conditions affecting bone density (e.g. renal osteodystrophy; inflammatory arthritis), bony defects requiring grafting, a poorly functioning contralateral TKA or revision regardless of function.
All TKAs were performed via a medial parapatellar approach using an intramedullary femoral alignment guide set at five-degrees and an extramedullary tibial alignment guide set at neutral in the coronal plane with a neutral posterior slope in the sagittal plane. All TKAs were cemented (Palacos®, Heraeus Medical, Hanau, Germany). The postoperative protocol was the same in all cases including deep vein thrombosis prophylaxis, prophylactic antibiotics, and follow-up schedule (8 weeks, 6 months, 1 year, and every 1 to 2 years thereafter). Physical therapy was initiated on the day of operation. Each exam was performed by the attending physician.
As per the study protocol, the surgeon switched from 1G to 2G a year into the study period. Data for demographic parameters including age, gender, race, and body mass index (BMI) were collected preoperatively. Scores from patient-reported outcome measures such as the Knee Injury and Osteoarthritis Outcome Survey-Joint Replacement (KOOS-JR) [10 (link)] and Knee Society clinical and radiographic scoring system (KSS) were collected at each office visit [11 (link)]. Scores from different components of KSS were reported separately. These components were objective knee score, functional score, patient satisfaction and expectation score. Intra- and post-operative complications, as well as any revisions, reoperations, and returns to operating room, were diligently recorded. All data were collected prospectively in an institutional database. This study represents a retrospective review of these prospectively collected data.
All TKAs were performed via a medial parapatellar approach using an intramedullary femoral alignment guide set at five-degrees and an extramedullary tibial alignment guide set at neutral in the coronal plane with a neutral posterior slope in the sagittal plane. All TKAs were cemented (Palacos®, Heraeus Medical, Hanau, Germany). The postoperative protocol was the same in all cases including deep vein thrombosis prophylaxis, prophylactic antibiotics, and follow-up schedule (8 weeks, 6 months, 1 year, and every 1 to 2 years thereafter). Physical therapy was initiated on the day of operation. Each exam was performed by the attending physician.
As per the study protocol, the surgeon switched from 1G to 2G a year into the study period. Data for demographic parameters including age, gender, race, and body mass index (BMI) were collected preoperatively. Scores from patient-reported outcome measures such as the Knee Injury and Osteoarthritis Outcome Survey-Joint Replacement (KOOS-JR) [10 (link)] and Knee Society clinical and radiographic scoring system (KSS) were collected at each office visit [11 (link)]. Scores from different components of KSS were reported separately. These components were objective knee score, functional score, patient satisfaction and expectation score. Intra- and post-operative complications, as well as any revisions, reoperations, and returns to operating room, were diligently recorded. All data were collected prospectively in an institutional database. This study represents a retrospective review of these prospectively collected data.
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