Morphometric Tibial Implant Decreases Posterior Overhang Rate and Improves Clinical Outcomes: Results of a Prospective, Matched Controlled Study

Abstract

The use of an MTT in TKA did not modify the tibial implant position in the axial plane; however, it decreased implant's posterior overhang and improved functional scores. The clinical improvement was mainly found on pain scores.

Better Implant Positioning and Clinical Outcomes With a Morphometric Unicompartmental Knee Arthroplasty. Results of a Retrospective, Matched-Controlled Study

“…A result less than 100% corresponded to a non-overflowing implant and a result greater than 100% to an overflowing implant. Medial overhang: distance in millimeters between the medial edge of the tibial component and the medial most border of the proximal tibia directly underneath the implant, as measured by Bizzozero et al [25]. Posterior overhang: distance in millimeters between the posterior edge of the tibial component tray and the posterior most border of the proximal tibia directly underneath the implant (Fig.…”

Does the overhang of tibial component in fixed bearing medial unicondylar knee arthroplasty affect 1-year results?

“…It is known that compliance decreases, especially as the tibia becomes smaller [12]. Although gender-specific implants are currently available, their efficacy is also controversial [18]. It should be taken into consideration that we had more female patients than males and they tend to have implants smaller in size.…”

Minimum Five Years Follow-Up of Total Knee Arthroplasty Using Morphometric Implants in Patients With Osteoarthritis

“…This is often not possible, partly because current traditional tibial components may not be of ideal shape and often require a compromise between optimal rotation and bone coverage [28,29]. To optimize rotationalcoverage ratios and limit the potential conflicts with the soft tissues, new designs of tibial implants have been developed using large anatomical databases and specific software simulating bone cuts [17]. Thus, morphometric trays have been designed to adapt not only to the morphology of the proximal tibial plateau, but also to its dimensions.…”

“…In vitro studies, using positioning simulations of the tray on the basis of computed tomography scans, demonstrated that a morphometric tray allows an optimum rotational positioning, while optimizing the tibial coverage without causing any posterolateral conflict with the soft tissues [31,32]. An in vivo prospective matched controlled study comparing morphometric and symmetric tibial tray conducted by Bizzozero et al [17] using the same design as evaluated in the present study demonstrated that bone coverage (90% vs 88%, P ¼ .07) and rotation (mean difference 0.7 ± 3 ; P ¼ .69) were not different between the 2 groups. But the percentage of patients with a posterior overhang was lower in the morphometric group (2/33 vs 14/33, P ¼ .01, odds ratio 10.3 [2.12-50.24]).…”