2021 ISAKOS Biennial Congress ePoster
Correction Of Coronal-Tibiofemoral Subluxation After Unicompartmental Knee Arthroplasty Results In Mid To Long Term Functional Improvement And May Be Affected By Tibia Component Obliquity
Kyung Jun Min, MD, Seoul, Seoul KOREA, REPUBLIC OF
Do-Young Park, MD, PhD, Suwon, Gyeonggi-do KOREA, REPUBLIC OF
Byoung-Hyun Min, MD, PhD, Suwon, Gyeonggi-Do KOREA, REPUBLIC OF
Keun Soo Kim, MD KOREA, REPUBLIC OF
Jun-Young Chung, MD, Suwon, Gyeonggi-do KOREA, REPUBLIC OF
Sumin Lim, MD, Gyeonggi-Do KOREA, REPUBLIC OF
Ajou University Hospital, Suwon, Gyeonggi-Do, KOREA, REPUBLIC OF
FDA Status Not Applicable
Summary
Correction of coronal-tibiofemoral subluxation after unicompartmental knee arthroplasty results in mid to long term functional improvement and may be affected by tibia component obliquity
ePosters will be available shortly before Congress
Abstract
Objective
While coronal tibiofemoral subluxation (CTFS) is a common finding in knee osteoarthritis associated with malalignment, its changes and effects after unicompartmental knee arthroplasty (UKA) are not well understood. We aimed to assess CTFS changes after UKA and analyze its effects on mid to long term functional outcomes. We also sought to analyze potential patient and surgical factors associated with CTFS changes after UKA.
Materials and Methods. We have retrospectively reviewed 127 consecutive patients who received primary fixed-bearing UKA for primary knee osteoarthritis with more than 5 years follow-up. Radiographic analysis included pre and postoperative CTFS and femur tibia angle, and surgical parameters of postoperative intraprosthetic divergence, tibia component obliquity, posterior slope angle, and component contact point. Clinical results were assessed Western Ontario Mcmaster University Osteoarthritis Index (WOMAC). Patients were dichotomized according to postoperative CTFS changes compared to preoperative values into ‘decreased’ and ‘increased’ groups. Statistical analysis between the two groups was done with independent t-test.
Results. Among 127 cases, 112 showed improved CTFS (3.24mm±1.96) while 15 showed worsened CTFS (-0.84mm±0.70) postoperatively (p<0.001). The ‘decreased’ group showed more improvement in terms of WOMAC compared to the ‘increased’ group (22.04 ± 12.35 vs. 10.8 ± 16.37, p<0.05). Among surgical factors, the ‘increased’ group showed more varus positioned implants compared to the ‘decreased’ group (tibia component obliquity, 87.99°±3.44 vs. 89.61°±2.91, p<0.05).
Conclusion. Patients with decreased CTFS after UKA showed better clinical results compared to patients with increased CTFS. Avoiding varus positioning of tibial implants during UKA may decrease postoperative CTFS.