Robotic-assisted bi-cruciate stabilized TKA with a 3-degree varus inclination does not affect PROMs, regardless of...

The Coronal Plane Alignment of the Knee (CPAK) is a classification that evaluates the joint line obliquity (JLO) and hip-knee-ankle angle (HKA) in osteoarthritis of the knee. The primary aim of this study was to evaluate whether changes in CPAK classification between pre- and postoperative states in patients who underwent robotic-assisted (RA) bi-cruciate stabilized (BCS) total knee arthroplasty (TKA) with a 3-degree varus inclination affected patient reported outcome measurements (PROMs).

This retrospective study involved 149 patients treated with bi-cruciate stabilized (BCS) TKA between 2019 and 2023 following a physiological alignment strategy and using image-free robotic-assisted (RA) technique. Pre- and postoperative CPAK classifications were compared, along with changes in arithmetic HKA (aHKA), JLO, and PROMs including the 2011 Knee Society Score, Western Ontario and McMaster Universities Arthritis Index score, Forgotten Joint Score 12, and Patella score were collected at a mean 1.95 years (range:1-5) postoperatively.

CPAK classification matched pre and postoperatively in 59.1% of cases. Regardless of CPAK classification matching, there were no significant differences in any of these PROMs. aHKA matching was observed in 71.8% of cases, and JLO matching in 81.2%. Comparisons of changes in aHKA and JLO also revealed no significant differences in PROMs.

Robotic-assisted "Physiological alignment" BCS TKA with 3-degree varus inclination does not affect PROMs, regardless of pre-arthritic CPAK classification matching. The pre- and postoperative CPAK classifications do not always correspond accurately.