2015 ISAKOS Biennial Congress ePoster #1442
Comparison of Range of Motion After TKA PS-Type vs. CS-Type
Hitoshi Sekiya, MD, Kawachi-Gun, Tochigi JAPAN
Shinkaminokawa Hospital, Kaminokawa, Tochigi, JAPAN
FDA Status Cleared
Summary: The purpose of this was to compare PS-type with CS-type. ROM, posterior instability were compared between the groups at 12 months follow-up.288 PS-type TKAs and 178 CS-type TKAs were performed. The results in this study revealed equally ROM after TKA with these types of implants, although flexion kinematics of the CS TKA knees might have paradoxical anterior femoral translation.
Range of motion (ROM) after total knee arthroplasty (TKA) is an important variable in determining clinical outcome. ROM of the posterior stabilized total knee prosthesis has had good result. Recently, with a new concept, tibial insert design of cruciate-substituting (CS-type) polyethylene insert is employed. However ROM of CS-type TKA is not still clarified. The purpose of this was to compare PS-type with CS-type. ROM, posterior instability were compared between the groups at 12 months minimum follow-up.
MATERIALS & METHODS
Between 2006 and 2013, 288 PS-type TKAs (Stryker Scorpion NRG PS-type) and 178 CS-type TKAs (Stryker Triathlon CS-type) were performed. All patients had PCL releases. The PS group included 245 women and 43 men with a mean age of 71.9 years. The CS group included 132 women and 36 men with a mean age of 75.5 years. We measured ROM and posterior instability (Active Quadricepus test), pre-operatively and after 12 months post-operatively.
The mean ROM was 121±16.9° in the PS group and 117±12.9C in the CS group at 12 months follow-up. No statistically significant differences were found between both groups with regard to the ROM. The Active Quadricepus test was -0.43±1.29mm in the PS group and 1.70±1.67mm in the CS group at 12 months follow-up. The PS group showed less posterior instability than the CS group.
The results in this study revealed equally ROM after TKA with these types of implants at 12 months follow-up, although flexion kinematics of the CS TKA knees might have paradoxical anterior femoral translation ( femoral roll-forward) at 90°of flexion.