An insert with less than spherical medial conformity causes a loss of passive internal rotation after calipered kinematically aligned TKA
Please always quote using this URN: urn:nbn:de:bvb:20-opus-266710
- Introduction In total knee arthroplasty (TKA), the level of conformity, a medial stabilized (MS) implant, needs to restore native (i.e., healthy) knee kinematics without over-tensioning the flexion space when the surgeon chooses to retain the posterior cruciate ligament (PCL) is unknown. Whether an insert with a medial ball-in-socket conformity and lateral flat surface like the native knee or a less than spherical medial conformity restores higher and closer to native internal tibial rotation without anterior lift-off, an over-tensionIntroduction In total knee arthroplasty (TKA), the level of conformity, a medial stabilized (MS) implant, needs to restore native (i.e., healthy) knee kinematics without over-tensioning the flexion space when the surgeon chooses to retain the posterior cruciate ligament (PCL) is unknown. Whether an insert with a medial ball-in-socket conformity and lateral flat surface like the native knee or a less than spherical medial conformity restores higher and closer to native internal tibial rotation without anterior lift-off, an over-tension indicator, when implanted with calipered kinematic alignment (KA), is unknown. Methods and Materials Two surgeons treated 21 patients with calipered KA and a PCL retaining MS implant. Validated verification checks that restore native tibial compartment forces in passive flexion without release of healthy ligaments were used to select the optimal insert thickness. A goniometer etched onto trial inserts with the ball-in-socket and the less than spherical medial conformity measured the tibial rotation relative to the femoral component at extension and 90° and 120° flexion. The surgeon recorded the incidence of anterior lift-off of the insert. Results The insert with the medial ball-in-socket and lateral flat surface restored more internal tibial rotation than the one with less than spherical medial conformity, with mean values of 19° vs. 17° from extension to 90° flexion (p < 0.01), and 23° vs. 20°-120° flexion (p < 0.002), respectively. There was no anterior lift-off of the insert at 90° and 120° flexion. Conclusion An MS insert with a medial ball-in-socket and lateral flat surface that matches the native knee's spherical conformity restores native tibial internal rotation when implanted with calipered KA and PCL retention without over-tensioning the flexion space.…
Author: | Alexander J. Nedopil, Adithya Shekhar, Stephen M. Howell, Maury L. Hull |
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URN: | urn:nbn:de:bvb:20-opus-266710 |
Document Type: | Journal article |
Faculties: | Medizinische Fakultät / Lehrstuhl für Orthopädie |
Language: | English |
Parent Title (English): | Archives of Orthopaedic and Trauma Surgery |
ISSN: | 1434-3916 |
Year of Completion: | 2021 |
Volume: | 141 |
Issue: | 12 |
Pagenumber: | 2287–2294 |
Source: | Archives of Orthopaedic and Trauma Surgery 2021, 141(12): 10.1007/s00402-021-04054-0 |
DOI: | https://doi.org/10.1007/s00402-021-04054-0 |
Pubmed Id: | https://pubmed.ncbi.nlm.nih.gov/34264381 |
Dewey Decimal Classification: | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Tag: | calipered; conforming; insert; kinematic alignment; medial stabilized; rotation; spherical; total knee arthroplasty; total knee replacement |
Release Date: | 2022/06/02 |
Licence (German): | CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International |