Polyethylene spinout in the Attune® Cruciate-Retaining Rotating-Platform (CR RP) total knee arthroplasty performed with a cruciate-sacrificing and measured-resection technique

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

Background

Posterior femoral condylar osteophytes were frequently observed in patients with the ultra-congruent (UC) deep-dish 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.

Do optional implants improve the femoral fit during total knee arthroplasty in Asians? Comparison of the femoral fit between single- and dual-option implants

BACKGROUND

The purpose of this study was to evaluate the femoral fit in Asian patients during total knee arthroplasty by examining whether (1) the advanced single-option implant improves the fit of the femoral component in both the anterior flange and distal cutting surface and (2) the dual-option implants show better fit than the advanced single-option implant.

METHODS

A total of 950 knees that underwent primary total knee arthroplasty were included. Two types of single-option implant systems (Optetrak Logic and Truliant) and three types of dual-option implant systems (Anthem, Attune, and Persona) were used. The difference between the resected surface of the femur and femoral component dimensions was analyzed in predefined six zones. Appropriateness of fit (good-fit, over-hang, under-hang) was also evaluated.

RESULTS

The advanced single-option implant showed higher rates of good-fit and lower rates of over-hang and under-hang in almost all distinct zones than the old version single-option implant. The advanced single-option implant demonstrated similar good-fit, higher over-hang and lower under-hang rates than the dual-option implants. All single-option implants showed significantly higher over-hang rate (P < 0.05) and lower under-hang rate (P < 0.05) than all dual-option implant systems in the anterior flange transverse area. The narrow option was only selected in 12-20% of all cases.

CONCLUSIONS

The advanced single-option implant system improved the fit of the femoral component when compared with the old version and showed similar good-fit rates when compared with the dual-option implant systems. The narrow option of the dual-option implant systems was used less frequently than expected in Asian knees.