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Published on: February 27, 2018
Bi-cruciate substituting total knee arthroplasty provides varus-valgus stability throughout the midflexion range
Kazunori Hino1, Tatsuhiko Kutsuna1, Kunihiko Watamori1
1Department of Orthopedic Surgery, Ehime University Graduate School of Medicine, Ehime, Japan.
Background:
Proper soft tissue balance is crucial for a successful clinical outcome after total knee arthroplasty (TKA). Bi-cruciate substituting (BCS)-TKA has been developed to more closely approximate normal knee characteristics. The purpose of the present study was to evaluate midflexion laxity before and after BCS-TKA using a navigation system, and assess the correlation between intraoperative laxity and the maximum flexion angle after surgery.
Methods:
Fifty-one knees in 46 patients with osteoarthritis replaced with BCS prosthesis were assessed. Manual mild passive internal-external rotational and varus-valgus stress was applied to the knees, and the maximum total laxity was measured automatically by a navigation system before and after TKA. The correlations with the range of motion (ROM) were evaluated using Spearman's correlation coefficients (ρ).
Results:
Internal-external stress assessment revealed no statistically significant difference at each flexion angle before and after BCS-TKA. In contrast, the varus-valgus stress assessment revealed that BCS-TKA had significantly decreased varus-valgus laxity from preoperative levels at 20-120° flexion angles. Furthermore, the maximum flexion angle at six months after surgery significantly correlated with the intraoperative laxity at deep flexion range.
Conclusion:
BCS-TKA stabilized varus-valgus laxity to better than preoperative levels at midflexion range.
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