Early Results of Unrestricted Kinematic Alignment in Cementless Total Knee Arthroplasty

Kinematic alignment (KA) in total knee arthroplasty (TKA) is well researched, but is defined heterogeneously, as technique may vary. There is less research concerninfiveg unrestricted KA (uKA). Cementless fixation in TKA has been shown to have excellent long-term survivorship and functional outcomes, but its use in combination with KA remains controversial. This paper intends to evaluate the short-term rates of aseptic loosening in the setting of cementless uKA TKA.

Prospectively collected data were queried for all primary, cementless TKAs performed by 1 surgeon from September 2022 to August 2024. This surgeon performed all manual primary TKAs in this window using conventional caliper-measured uKA. A total of 335 primary cementless uKA TKA cases were included. The primary outcome was aseptic loosening. The secondary outcomes included all-cause revisions, complications, and patient-reported outcome measures.

Of the 335 cases, 1 patient was revised for tibial component fixation failure within the first year postoperatively. 2 cases were revised for acute periprosthetic joint infections. There was 1 case of patellar subluxation and 1 case of a wound dehiscence secondary to traumatic fall. There were 10 medical complications unrelated to the implant. Short-term survivorship free of tibial or femoral revision was 99.4% at 1 year.

This is the largest investigation reporting promising early results of cementless TKA utilizing a uKA technique. Our data suggest early outcomes of combining uKA with cementless fixation are promising. Longer-term follow-up and larger cohort studies will be required to further evaluate rates of revision for aseptic causes with cementless implants.