Orthopedics Today Hawaii
Orthopedics Today Hawaii
January 16, 2020
1 min read

Medially stabilized TKR designs are more sagittally stable

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Andrew J. Shimmin

KOLOA, Hawaii — Medially stabilized TKR designs are more sagittally stable and studies have shown better patient-reported outcomes with their use, according to a presenter here at Orthopedics Today Hawaii.

“The native knee is not symmetrical. Most TKR designs are symmetrical. Sagittal stability, whatever the design, achieves better patient-reported outcomes,” Andrew J. Shimmin, MBBS, FRACS, said, here.

Shimmin said sagittal stability is important, and multicenter studies have shown medially stabilized TKR designs function as intended.

“All we want is a happy patient. A happy patient is related to the kinematic outcome of the knee replacement that makes a patient happy,” he said.

Kinematic outcome is determined by component geometry, component alignment and patient-specific musculoskeletal environment, he said.

Medial and lateral compartments of the tibiofemoral joint are asymmetric. The medial articulation is concave, and the lateral tibial articular surface is convex. He said medially stabilized designs show highly conforming medial articulation, stabilization from medial ball-and-socket effect and stability throughout range of motion without the need for PCL or a post and cam mechanism. Medially stabilized designs also show translation on the lateral side, if required, and are bone conserving without the need for box cut or trochlear groove.

He said video fluoroscopy and computational modelling suggest medially stabilized TKR designs show similar tibiofemoral kinematics to the native knee, including medial stability. lateral translation if required by the activity and absence of paradoxical anterior translation. – by Kristine Houck, MA, ELS


Shimmin AJ. Medially stabilized TKR designs. Presented at: Orthopedics Today Hawaii; Jan. 12-16, 2020; Koloa, Hawaii.

Disclosure: Shimmin reports he is a consultant for Corin, Matortho and Smith & Nephew; and receives royalties from Corin and Matortho.