Statistical design of unicompartmental tibial implants and comparison with current devices

Fitzpatrick, Clare K.; FitzPatrick, D.; Lee, Jordan; Auger, D D

doi:10.1016/j.knee.2006.11.005

Cited by 55 publications

(34 citation statements)

References 8 publications

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“…There are no reports to date that suggest a link between early tibial implant failure and insufficient bone coverage even though we may expect that cortical bearing of the tibial component should be better. Few studies [5,16] have analyzed the correlation between tibial anatomy and implant design for UKA. Fitzpatrick et al [5] measured the shape of the tibial plateau by modeling of the tibial resection as described by Surendran et al [16].…”

Section: Discussionmentioning

confidence: 99%

Lateral versus medial tibial plateau: morphometric analysis and adaptability with current tibial component design

Servien

Saffarini²,

Lustig

et al. 2008

Knee Surg Sports Traumatol Arthr

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The purpose of this study was to analyze the in vivo dimensions of each tibial plateau for planning of unicompartmental knee arthroplasty (UKA), and to compare the morphometric data to the dimensions of nine current designs of UKA tibial components. Thirty-seven knees (31 females and 6 males) operated on with UKA were studied. All patients were examined postoperatively using computed tomography (CT). There were 18 lateral and 19 medial UKAs. On the CT scan, each operated tibial plateau was measured in the transverse plane at the resection level, just below the full polyethylene tibial component. We measured the length of the anteroposterior (AP) cut as well as the maximal mediolateral dimension of the resected plateau (perpendicular to the AP cut). We compared the measurements with nine current UKA systems: Accuris (Smith and Nephew), Advance (Wright Medical), HLS Uni Evolution (Tornier), Miller-Galante and "ZUK" (Zimmer), Oxford and Oxford alpha (Biomet), Preservation (DePuy) and Unix (Stryker). There was good correlation between patient height and mediolateral dimension (r=0.6), and between patient height and area of total tibial plateau (r=0.7). The anteroposterior dimension was greater for the medial plateau (mean 50.8 mm, SD 3.3) than for the lateral plateau (mean 47.2 mm, SD 3.3). This difference was statistically significant (P=0.0016). Some UKA implants are designed with an asymmetric femoral component, but none have an asymmetric tibial component. The present study suggests, however, that the shape of the medial tibial plateau differs from that of the lateral plateau. This difference can lead to mediolateral overhang for medial UKA, if the surgeon aims for optimal anteroposterior coverage.

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Section: Discussionmentioning

confidence: 99%

Lateral versus medial tibial plateau: morphometric analysis and adaptability with current tibial component design

Servien

Saffarini²,

Lustig

et al. 2008

Knee Surg Sports Traumatol Arthr

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“…Importantly, because the implant is patient specific, it provides the potential for complete cortical rim coverage (>95%) (Fig. 4 ), a result that cannot be achieved with off-the-shelf implants [12]. The placement of the fixation features for that patient is based on design principles for unicondylar implants [13].…”

Section: Materials and Methodologymentioning

confidence: 99%

Unicompartmental Knee Resurfacing: Enlarged Tibio-Femoral Contact Area and Reduced Contact Stress Using Novel Patient-Derived Geometries

Steklov¹,

Slamin²,

Srivastav³

et al. 2010

TOBEJ

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Advances in imaging technology and computer-assisted design (CAD) have recently enabled the introduction of patient-specific knee implant designs that hold the potential to improve functional performance on the basis of patient-specific geometries, namely a patient-specific sagittal and coronal curvature, as well as enhanced bone preservation. The objective of this study was to investigate the use of a novel implant design utilizing a patient specific sagittal J-curve on the femoral component combined with a novel constant, patient-derived femoral coronal curvature and to assess tibio-femoral contact area and contact stress on a femur matched curved tibial polyethylene insert. Mean contact area and standard deviations were 81±5, 96±5 and 74±4 mm2 for the heel strike, toe off and mid-stance positions, respectively. Mean contact stress and standard deviations were 23.83±1.39, 23.27±1.14 and 20.78±0.54 MPa for the heel strike, toe off and mid-stance positions, respectively. Standard deviations of the measurements were small, not exceeding 6-7% confirming the consistency of loading conditions across different flexion angles. The results were comparable to those reported for standard, off-the-shelf fixed-bearing implants with paired femoral and tibial geometries. These data show that a constant coronal curvature can be applied to a patient-specific implant by measuring coronal curvatures across the femoral condyle in each patient and by deriving an average curvature. This novel approach combines unique benefits of patient-specific geometry with proven design concepts for minimizing polyethylene wear.

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“…Furthermore, coronal plane position error may lead to abnormal contact stress and MCL tension [18]. Historical UKA designs did not aim at reproducing tibial plateau morphometry [19] but were rather built as simple symmetric shape. Consecutively, compromises in size and rotation positioning might have to be realized intraoperatively [18,20].…”

Section: Introductionmentioning

confidence: 99%

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

Escudier

Jacquet

Flécher

et al. 2019

The Journal of Arthroplasty

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Keywords:unicompartmental knee arthroplasty morphometric tibial tray implant positioning medial overhang tibial bone coverage a b s t r a c t Background: During medial unicompartmental knee arthroplasty (UKA), tibial tray implantation requires compromise between bone coverage and rotational position. It was hypothesized that morphometric tibial tray (MTT) would improve implant positioning and subsequently clinical outcomes as compared to symmetric tibial tray (STT). Methods: A total of 106 patients who underwent medial UKA in our department between January 2017 and March 2018 were included matched on gender and age (53 in each group). Inclusion criteria were symptomatic medial femorotibial osteoarthritis, functional anterior cruciate ligament, primary arthritis, or osteonecrosis. Rotation of the tibial implant, tibial bone coverage, medial and posterior overhang were assessed with a postoperative computed tomography scan. The Knee Society Score (KSS), the Knee injury and Osteoarthritis Outcome Score Short Form (KOOS SF), and the quality of life score EuroQoL 5-Dimensions 3-Levels (EQ5D3L) were assessed at a minimum of 1-year follow-up. Results: Implants of the STT group exhibited more external rotation (6.3 ± 4.02 vs 4.6 ± 3.59 ; P ¼ .04), and medial and posterior overhang >3 mm (35% vs 0% and 22% vs 0%; P < .0001) but no difference for tibial bone coverage (97.3% ± 11.35% vs 94.7% ± 10.89%; P ¼ .23). Global KSS (188.6 ± 6.6 vs 175.2 ± 31.7; P < .01), KOOS SF (16.9 ± 6.1 vs 22.5 ± 11.8; P < .003), and EQ5D3L (1 ± 0.1 vs 0.9 ± 0.2; P < .001) were higher in MTT group. According to the multivariate analysis, MTT had a positive independent effect on the KSS, KOOS SF, and EQ5D3L. Conclusion: The use of an MTT in medial UKA allowed better implant positioning when decreasing the rate of overhang; superior short-term clinical outcomes were found as compared to STT.

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Statistical design of unicompartmental tibial implants and comparison with current devices

Cited by 55 publications

References 8 publications

Lateral versus medial tibial plateau: morphometric analysis and adaptability with current tibial component design

Lateral versus medial tibial plateau: morphometric analysis and adaptability with current tibial component design

Unicompartmental Knee Resurfacing: Enlarged Tibio-Femoral Contact Area and Reduced Contact Stress Using Novel Patient-Derived Geometries

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

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