Does a Modified Gap-balancing Technique Result in Medial-pivot Knee Kinematics in Cruciate-retaining Total Knee Arthroplasty?: A Pilot Study

Fitz, Wolfgang; Sodha, Sonal; Reichmann, William M.; Minas, Tom

doi:10.1007/s11999-011-2121-6

Cited by 30 publications

(36 citation statements)

References 24 publications

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“…Most studies show that the medial femoral condyle hardly moves anteroposteriorly from full extension to 120°of flexion, whereas the lateral femoral condyle moves posteriorly to a variable extent. From 120°to full flexion, both condyles roll back onto the posterior horn [16,17]. Knees with a unicondylar TKA show an almost physiological combination of movements, with a primarily rollback mechanism of the lateral femoral condyle during weight-bearing flexion.…”

Section: Discussionmentioning

confidence: 99%

“…All kinematic analyses were recorded after temporarily occlusion of the joint capsule by clamping jaws. The modified gap-balancing technique was based on the principles of John Insall's classic gap-balancing technique [19], modified by Fitz et al, resulting in a medial pivoting knee kinematic [16]. It comprised restoration of the medial condylar J curve with less distal femoral resection (to result in a "true" cut of eight millimetres representing implant thickness, a strict cut of eight millimetres, but the assumed cartilage and bone loss of the affected condyle was subtracted from this cut).…”

Section: Methodsmentioning

confidence: 99%

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Improved kinematics of total knee replacement following partially navigated modified gap-balancing technique

Baier

Fitz

Craiovan

et al. 2013

International Orthopaedics (SICOT)

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Purpose Navigation-based total knee arthroplasty (TKA) has proven its value for restoration of the limb axis. However, patient-orientated results after TKA show a wide variation from the correct implantation technique. Nonphysiological kinematics without posterior femoral rollback and tibial internal rotation in flexion could be one reason for this. We postulated that a modified gap-balancing technique with navigation of the tibia alone, in comparison to a conventional navigated technique, would: (1) obtain lateral femoral rollback, (2) alter condylar liftoff without midflexion instability, (3) significantly differ in femoral and tibial cuts, (4) not be inferior in leg-axis restoration and (5) be comparable in clinical short-term scores. Methods In this prospective study, we compared in vivo navigation-based kinematics pre-and postoperatively of 40 consecutive TKA comprising 21 conventional navigationbased TKA and 19 TKA with the modified gap-balancing technique and a reduced navigation workflow. All cuts were double checked and compared with cuts proposed by the navigation system. Clinical results were assessed preoperatively and six months postoperatively. Results The modified gap-balancing technique resulted in significantly increased lateral femoral rollback (mean 16.3 mm) and lateral condylar liftoff (mean 1.3 mm) compared to the conventional group. The modified technique comprised an average of 2.1 mm less distal femoral resection and an average of 4°less external rotation and 3.5°more flexion of the femoral component compared with the control group. Average tibial resection height was 1.1 mm greater and average tibial slope was 0.5°elevated compared to the control group. A neutral leg axis was achieved in all cases. Results showed no significant differences in clinical scores between groups. Conclusion A partial navigation solely of the tibial cut can securely restore the leg axis. Modification of the surgical technique can possibly reproduce more physiological knee kinematics with higher lateral femoral rollback in flexion without midflexion instability. This might help reduce postoperative problems with the new implant and thus reduce the amount of unsatisfactory results. Despite equal short-term results, mid-to long-term results are needed to prove whether or not this correlates with better clinical results and at least equal implant longevity.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Improved kinematics of total knee replacement following partially navigated modified gap-balancing technique

Baier

Fitz

Craiovan

et al. 2013

International Orthopaedics (SICOT)

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“…Using a magnetic resonance imaging (MRI) technique in cadaver and living knees, Hill [11] described a pattern of no anteroposterior movement medially, but a lateral roll-back combined with sliding laterally during flexion. After TKR using 3D matching techniques, Fitz et al [13] detected tibial internal rotation during knee flexion using a new gapbalancing technique with a more anatomical restoration of the distal and posterior medial femoral condyle. In knees with standard TKR, they predominantly found tibial external rotation during flexion [13].…”

Section: Introductionmentioning

confidence: 99%

“…After TKR using 3D matching techniques, Fitz et al [13] detected tibial internal rotation during knee flexion using a new gapbalancing technique with a more anatomical restoration of the distal and posterior medial femoral condyle. In knees with standard TKR, they predominantly found tibial external rotation during flexion [13].…”

Section: Introductionmentioning

confidence: 99%

Comparing navigation-based in vivo knee kinematics pre- and postoperatively between a cruciate-retaining and a cruciate-substituting implant

Baier

Springorum

Götz

et al. 2013

International Orthopaedics (SICOT)

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Purpose Individual physiological knee kinematics are highly variable in normal knees and are altered following cruciatesubstituting (PS) and cruciate-retaining (CR) total knee arthroplasty (TKA). We wanted to know whether knee kinematics are different choosing two different knee designs, CR and PS TKA, during surgery using computer navigation. Methods For this purpose, 60 consecutive TKA were randomised, receiving either CR (37 patients) or PS TKA (23 patients). All patients underwent computer navigation, and kinematics were assessed prior to making any cuts or releases and after implantation. Outcome measures were relative rotation between femur and tibia, measured medial and lateral gaps and medial and lateral condylar lift-off. Results We were not able to demonstrate a significant difference in femoral external rotation between either group prior to implantation (7.9°CR vs. 7.4°PS) or after implantation (9.0°C R vs. 11.3°PS), both groups showed femoral roll-back. It significantly increased pre-to postoperatively in PS TKA. In the CR group both gaps increased, the change of the medial gap was significantly attributable to medial release. In the PS group both gaps increased and the change of the medial and of the lateral gap was significant. Condylar lift-off was observed in the CR group during 20°and 60°of flexion. Conclusion This study did not reveal significant differences in navigation-based knee kinematics between CR and PS implants. Femoral roll-back was observed in both implant designs, but significantly increased pre-to postoperatively in PS TKA. A slight midflexion instability was observed in CR TKA. Intra-operative computer navigation can measure knee kinematics during surgery before and after TKR implantation and may assist surgeons to optimise knee kinematics or identify abnormal knee kinematics that could be corrected with ligament releases to improve the functional result of a TKR, whether it is a CR or PS design. Our intraoperative finding needs to be confirmed using fluoroscopic or radiographic 3D matching after complete recovery from surgery.

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“…In doing so, the anatomic knee joint line is restored, and flexion gap laxity is minimized. This can be accomplished to some degree with standard, off the shelf implants, using a modified gap balancing technique [16] where the distal and posterior medial femur is restored and more bone is resected off the tibia using a CR functional approach without changing the joint line relying on the mechanical axis. By reestablishing the correct joint line, the center of rotation of the medial and lateral ligaments is properly restored, allowing for more normal kinematic motion after soft tissue balancing.…”

Section: Introductionmentioning

confidence: 99%

Design rationale for customized TKA: a new idea or revisiting the past?

Schwechter

Fitz

2012

Curr Rev Musculoskelet Med

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Today's most basic and important total knee replacement design concepts arose out of an earlier era in which 2 distinct approaches emerged, functional and anatomic. Functional approaches simplified knee kinetics, were easier to implant, and gained widespread popularity, in part, from their inventory control. Anatomic approaches were an attempt to recreate normal knee motion with low prosthetic contact stress. Historically, however, they became impractical to produce because of the cost of maintaining a wide variety of anatomic knee implants. New customized designs may return the anatomic design to favor due to several key features that borrow anatomic principles developed in the past, and improved with new ideas.

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Does a Modified Gap-balancing Technique Result in Medial-pivot Knee Kinematics in Cruciate-retaining Total Knee Arthroplasty?: A Pilot Study

Cited by 30 publications

References 24 publications

Improved kinematics of total knee replacement following partially navigated modified gap-balancing technique

Improved kinematics of total knee replacement following partially navigated modified gap-balancing technique

Comparing navigation-based in vivo knee kinematics pre- and postoperatively between a cruciate-retaining and a cruciate-substituting implant

Design rationale for customized TKA: a new idea or revisiting the past?

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