Kinematic vs mechanical alignment RCT (Dossett)

A randomised controlled trial of kinematically and mechanically aligned total knee replacements: two-year clinical results.

Dossett HG, Estrada NA, Swartz GJ, et al. The bone & joint journal 2014 · PMID 24986944 · doi:10.1302/0301-620x.96b7.32812

Question

Does kinematic alignment give better outcomes than mechanical alignment in total knee replacement?

Design

Single-centre RCT with 2-year follow-up.

Patients

Patients undergoing primary TKA for osteoarthritis at a US veterans' hospital.

Intervention

Kinematically aligned TKA using patient-specific guides

Comparison

Mechanically aligned TKA using conventional instruments

Primary outcome

Pain relief and function (Oxford Knee Score, WOMAC, KSS) at 2 years

Key result

Kinematically aligned knees had significantly better pain relief, Oxford, WOMAC and Knee Society scores and greater flexion at 2 years than mechanically aligned knees.

Limitations

Small single-centre trial with short follow-up and a predominantly male veteran population; later trials and meta-analyses show smaller or no differences.

Impact on practice

Key trial behind the growth of kinematic and personalised alignment philosophies, but long-term survival data are needed before replacing mechanical alignment as standard.