Kinematic versus mechanically aligned total knee arthroplasty: no difference in frequency of arthroscopic lysis of adhesions for arthrofibrosis.

Arthrofibrosis is a condition that can cause excessive scar tissue formation, leading to painful restriction of joint motion. Following total knee arthroplasty (TKA), significant arthrofibrosis can result in permanent deficits in range of motion (ROM) if not treated. Although arthroscopic lysis of adhesions (ALOA) reliably improves post-TKA ROM if performed in a timely fashion, it exposes patients to additional anesthesia, heightens the risk of infection, and increases overall medical expenses. Kinematically aligned TKA has emerged as an alternative method to mechanically aligned, basing bony cuts off of the patient's pre-arthritic anatomy while limiting need for soft tissue and ligamentous releases. This study aimed to determine whether there is a difference in the frequency of post-TKA arthrofibrosis requiring ALOA between kinematic and mechanically aligned TKA. Between 2012 and 2019, a retrospective analysis was conducted based on a single surgeon's experience. Two cohorts were made based on alignment technique. Postoperatively, patients were diagnosed with arthrofibrosis and indicated for ALOA if they had functional pain with < 90 degrees of terminal flexion at 6 weeks postoperatively despite aggressive physical therapy. Frequency of ALOA was recorded for each cohort and was regressed using independent samples t-test. The results showed no significant difference between the mechanical and kinematic cohorts for frequency of ALOA following TKA (13.2% vs. 7.3%; p = 0.2659). However, the kinematic cohort demonstrated significantly greater post-ALOA ROM compared to the mechanical group (129° vs. 113°; p = 0.0097). Future higher-powered, prospective studies are needed to clarify whether a significant difference in rates of MUA/ALOA exists between the two alignment techniques.