Clin Orthop Surg.  2024 Jun;16(3):413-421. 10.4055/cios23061.

Clinical Relevance of Posterior Osteophyte Formation in Ultra-congruent Total Knee Arthroplasty: Midterm Radiographic Rollback and Impingement Analysis

• Jeong HW
• Yoo HJ
• Park SY
• Lee YS

• KMID: 2555784
• DOI: http://doi.org/10.4055/cios23061

Abstract

Background
Posterior femoral condylar osteophytes were frequently observed in patients with the ultra-congruent (UC) deepdish design prosthesis. Therefore, the purpose of the present study was to verify the clinical relevance of osteophyte formation in the UC design.
Methods
From March 2014 to February 2018, a comparative study was conducted on 96 knees using the UC design. They were divided into 2 groups (group 1: osteophyte +, group 2: osteophyte –). Intraoperative findings, indirect femoral rollback assessment using 30° flexion and active full flexion lateral radiographs, serial change of the osteophyte, and outcomes were compared.
Results
The mean follow-up period was 49.35 ± 3.47 months in group 1 and 47.52 ± 3.37 months in group 2. Posterior component coverage was significantly different between the groups: group 1 exhibited more underhang and group 2 exhibited more overhang (p = 0.022). On the indirect assessment of the femoral rollback, there was a statistically significant difference in deep flexion and change in distance (p < 0.001 and p < 0.001, respectively). There was no statistical difference between the 2 groups in the American Knee Society knee and function score, and group 2 showed significant improvement in pain compared to group 1 in Western Ontario and McMaster University Arthritis Index pain score (p = 0.029).
Conclusions
Posterior condylar osteophyte formation was related to posterior impingement. It was more frequently observed in the underhang of the femoral component and insufficient femoral rollback. In addition, it changed with time and caused negative effects, including a gradual decrease in flexion and more pain.

Keyword

Total knee arthroplasty; Ultra-congruent; Femoral rollback; Osteophyte; Outcome