Analysis of patterns of knee motion walking for four types of total knee implants.

The pattern of normal knee joint motion was compared with the pattern of knees after arthroplasty operations with: (a) variable axis, (b) geometric, (c) Herbert and (d) Shiers implants. The pattern of motion during walking was not implant-specific. Considerable variation in the transverse and coronal planes occurs in normal and postimplant knees. The magnitude of stance phase flexion did vary between the implants studied. Loosening and breakage are most closely related to design constraints in the coronal and transverse planes where there is considerable variation from patient to patient.