Poor functional outcomes and aseptic loosening increase when total knee arthroplasty is performed on osteoporotic patients. This biomechanical study evaluated the effect of stem extension on the stability of tibial fixation using different cementing techniques.
A standard design tibial tray was implanted in a replica of a male osteoporotic tibia. Twenty-four implantations were performed using three variations of implant and cementing, and then mounted on a material testing machine load frame at 500 cycles of multiaxial loading simulating walking. The three-dimensional components of tray-tibia micromotion were measured.
The primary implant total interface motion with surface cementing was 25.9 μm ± 14.7 μm and 10.6 μm ± 7.6 μm with full cementing (P = 0.001). The three-dimensional motion of fully cemented primary implants with stem extension was 4.4 μm ± 3.9 μm, which represents a decrease in micromotion of 83% in surface cemented primary implants (P < 0.0001) and 58% in the fully cemented components without stem extension (P < 0.009).
Fully cemented primary implants with stem extensions demonstrated decreased micromotion and should be considered for use in osteoporotic total knee arthroplasty patients.
From Houston Methodist Orthopedics & Sports Medicine, Houston Methodist Hospital, Houston, TX (Dr. Walsh, Dr. Canham, and Dr. Incavo), the Institute of Orthopedic Research & Education, Houston Methodist Hospital, Houston, TX (Dr. Han, Ms. Gonzalez, and Dr. Noble).
Correspondence to Dr. Incavo: firstname.lastname@example.org
Dr. Noble or an immediate family member has received royalties from Stryker and Zimmer Biomet; serves as a paid consultant to Zimmer Biomet; has stock or stock options held in Joint View; has received research or institutional support from CeramTec, DJO Global, Microport, Smith & Nephew, and Zimmer Biomet; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from the Musculoskeletal Transplant Foundation; and serves as a board member, owner, officer, or committee member of the International Society for Technology in Arthroplasty and the Knee Society. Dr. Incavo or an immediate family member has received royalties from Innomed, Kyocera, Osteoremedies, Smith & Nephew, Wright Medical Group, and Zimmer Biomet; serves as a paid consultant to Zimmer Biomet; has stock or stock options held in Nimbic Systems; and serves as a board member, owner, officer, or committee member of the Knee Society. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Walsh, Dr. Han, Dr. Canham, and Ms. Gonzalez.
Both first authors, Christopher P. Walsh, MD and Shuyang Han, PhD, contributed equally to the work.