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Bone & Joint Open
Vol. 5, Issue 7 | Pages 592 - 600
18 Jul 2024
Faschingbauer M Hambrecht J Schwer J Martin JR Reichel H Seitz A

Aims

Patient dissatisfaction is not uncommon following primary total knee arthroplasty. One proposed method to alleviate this is by improving knee kinematics. Therefore, we aimed to answer the following research question: are there significant differences in knee kinematics based on the design of the tibial insert (cruciate-retaining (CR), ultra-congruent (UC), or medial congruent (MC))?

Methods

Overall, 15 cadaveric knee joints were examined with a CR implant with three different tibial inserts (CR, UC, and MC) using an established knee joint simulator. The effects on coronal alignment, medial and lateral femoral roll back, femorotibial rotation, bony rotations (femur, tibia, and patella), and patellofemoral length ratios were determined.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 43 - 43
1 Apr 2018
Seitz A Lippacher S Natsha A Reichel H Ignatius A Dürselen L Dornacher D
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Introduction

The medial patellofemoral ligament (MPFL) is the main stabilizer of the patella and therefore mostly reconstructed in the surgical correction of patellofemoral dislocation. Various biomechanical and clinical studies have been conducted on MPFL reconstruction, while the patellofemoral contact pressure (PFCP) which is indicated as one of the predictors of retropatellar osteoarthritis was neglected. Therefore, the aim of this study was to investigate how different MPFL reconstruction approaches affect PFCP.

Material & Methods

After radiographic examination and preparation six human cadaveric knee joints (52.1 ± 8.4yrs) were placed in a 6-DOF knee simulator. Three flexion-extension cycles (0–90°) were applied, while the extensor muscles (175N) and an axial joint load (200N) were simulated. PFCP was measured in knee flexion of 0°, 30° and 90° using a calibrated pressure measurement system (K-Scan, Tekscan Inc., USA). The following MPFL conditions were examined: native (Pnat), anatomical reconstruction (Pa), proximal and distal patellar single-bundle reconstruction (Pp, Pd), proximal and ventral femoral reconstruction (Fp, Fv). The cohesive gracillis graft of each knee was used for MPFL reconstruction. Further, the effect of three different graft pre-tensioning levels (2N, 10N, 20N) on the PFCP were compared. Nonparametric statistical analysis was performed using SPSS (IBM Inc., USA).


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_II | Pages 160 - 161
1 May 2011
Majewski M Vögele S Seitz A Dürselen L
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Introduction: Previous work has shown that fixation of meniscus tears supports healing by preventing tears from gapping. However, an anterior cruciate ligament (ACL) insufficiency might increase the loads especially on the posterior horns of the meniscus. The aim of this study was to test an ACL tear results in wider gaps of longitudinal meniscal tears.

Methods: 3 cm longitudinal tears were artificially set in the posterior horn of the medial menisci in 10 human cadaver knee joints. The medial plateau of the joints was replaced by a translucent copy, under which an arthroscope was positioned to observe the gapping phenomenon of the meniscal tears. The knee specimens were flexed and extended in a motion and loading simulator allowing for all degrees of freedom. The maximum gap width occurring during a flexion-extension cycle was registered.

Results: Longitudinal meniscal tears showed significantly wider gaps after cutting the ACL (p< 0.01). However, refixation of the tears with suture anchors significantly reduced the gap width to much lower values (p< 0.01), still higher then with intact ACL.

Conclusion: The results indicate that medial meniscal tears in the posterior horn are exposed to higher loads in case of an ACL insufficiency. A missing ACL leads to increased anterior instability, which obviously results in wider tear gaps also in case of tear fixation with an implant. This confirms from a biomechanical point of view the clinical finding that meniscus repair is significantly enhanced when combined with ACL reconstruction.