Tibial Plateau Coverage in Total Knee Arthroplasty

IntroductionThe implantation of a total knee arthroplasty (TKA) requires, among other considerations, correct positioning of the tibial component to provide the best long-term stability of the prosthesis [12]. Lotke and Ecker [19] insist upon adequately setting the tibial component in the frontal plane, while other authors identify mispositions of the tibial tray in the transverse plane [8] as another possible source of failure. Indeed, malrotating the tibial component with respect to the femoral one [4,18,23] can lead to premature tibial polyethylene wear, one of the most common causes of revision in TKA [5].Concerning the position of the prosthetic tibial tray in the transverse plane, the surgeon should basically integrate two factors simultaneously when implanting it. Both an 'optimal' bone coverage ensuring thorough stability and a satisfactory extensor apparatus alignment providing a harmonious patellofemoral tracking should be supplied by the tibial component.Optimal bone coverage is achieved when the tibial component covers most of the underlying tibial plateau [9,12,16] or, more precisely, when it provides a maximal Abstract Correct positioning of the tibial component in total knee arthroplasty (TKA) must take into account both an optimal bone coverage (defined by a maximal cortical bearing with posteromedial and anterolateral support) and satisfactory patellofemoral tracking. Consequently, a compromise position must be found by the surgeon during the operation to simultaneously meet these two requirements. Moreover, tibial tray positioning depends upon the tibial torsion, which has been shown to act mainly in the proximal quarter of the tibia. Therefore, the correct application of the tibial tray is also theoretically related to the level of bone resection. In this study, we first quantified the torsional profile given by an optimal bone coverage for a symmetrical tibial tray design and for an asymmetrical one. Then, for the two types of tibial trays, we measured the angle difference between optimal bone coverage and an alignment on the middle of the tibial tubercule. Results showed that the values of the torsional profile given by the symmetrical tray were more scattered than those from the asymmetrical one. However, determination of the mean differential angle between the position providing optimal bone coverage and the one providing the best patellofemoral tracking indicated that the symmetrical prosthetic tray offered the best compromise between these two requirements. Although the tibiofemoral joint is known to be asymmetric in both shape and dimension, the asymmetrical tray chosen in this study was found to fulfill this compromise with more difficulty.

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“…We agree on this particular point with Incavo et al [12], who studied the tibial plateau coverage of various prosthetic trays.…”

Section: Discussionsupporting

confidence: 92%

Tibial component positioning in total knee arthroplasty: bone coverage and extensor apparatus alignment

Lemaire

Pioletti

Meyer

et al. 1997

Knee Surgery, Sports Traumatology, Arthroscopy

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“…Berger and Rubash reported that internal rotation of the tibial component from 3°to 8°correlated with patellar subluxation, whereas internal rotation of 7°to 17°c orrelated with findings of patellar dislocation or patellar prosthesis failure [4]. Our data offer little improvement over coverage values reported over two decades ago, suggesting that contemporary implant designs have not solved this problem [14]. There is also literature to demonstrate that accepting some uncovered posterior medial tibial bone aids in the proper rotational positioning of the tibial component [12].…”

Section: Discussioncontrasting

confidence: 51%

Maximizing Tibial Coverage Is Detrimental to Proper Rotational Alignment

Martin

Saurez

Ismaily

et al. 2014

Clinical Orthopaedics &Amp; Related Research

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Background Traditionally, the placement of the tibial component in total knee arthroplasty (TKA) has focused on maximizing coverage of the tibial surface. However, the degree to which maximal coverage affects correct rotational placement of symmetric and asymmetric tibial components has not been well defined and might represent an implant design issue worthy of further inquiry. Questions/purposes Using four commercially available tibial components (two symmetric, two asymmetric), we sought to determine (1) the overall amount of malrotation that would occur if components were placed for maximal tibial coverage; and (2) whether the asymmetric designs would result in less malrotation than the symmetric designs when placed for maximal coverage in a computer model using CT reconstructions. Methods CT reconstructions of 30 tibial specimens were used to generate three-dimensional tibia reconstructions with attention to the tibial anatomic axis, the tibial tubercle, and the resected tibial surface. Using strict criteria, four commercially available tibial designs (two symmetric, two asymmetric) were placed on the resected tibial surface. The resulting component rotation was examined. Results Among all four designs, 70% of all tibial components placed in orientation maximizing fit to resection surface were internally malrotated (average 9°). The asymmetric designs had fewer cases of malrotation (28% and 52% for the two asymmetric designs, 100% and 96% for the two symmetric designs; p \ 0.001) and less malrotation on average (2°and 5°for the asymmetric designs, 14°for both symmetric designs; p \ 0.001). Conclusions Maximizing tibial coverage resulted in implant malrotation in a large percentage of cases. Given similar amounts of tibial coverage, correct rotational positioning was more likely to occur with the asymmetric designs. Clinical Relevance Malrotation of components is an important cause of failure in TKA. Priority should be given to correct tibial rotational positioning. This study suggested that it is easier to balance rotation and coverage with asymmetric tibial baseplates; clinical research will need to determine whether the observed difference affects patellar tracking, loosening rates, or the likelihood of revisions after TKA.

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“…Maximal implant coverage on the bone surface minimizes the stress applied to the bone-implant interface [4,5] . Most TKA prosthesis designs are based on the anthropometry of western population, which differs from Asian knee morphometry [3] .…”

Section: Discussionmentioning

confidence: 99%

“…Anthropometric studies have shown that there are striking variations in knee morphology between the Asian and western population [3] . In TKA, maximal implant coverage on the bone surface minimizes the stress applied to the bone-implant interface [4,5] . A good shape of the knee prosthesis which matches the resected surface of knee has been reported as a factor for long-term survivorship in TKA [6] .…”

Section: Introductionmentioning

confidence: 99%

Computer tomography 3D reconstruction based study of knee anthropometry of Indian population: Comparison with other ethnic groups and current TKA implants

Agrawal¹,

Dalei²,

Reddy³

2017

Int. J. Orthop. Sci.

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Introduction: Most of the implants used for total knee arthroplasty in Asian patients have been produced based on anthropometry of Western people. Anthropometric studies have shown that there are significant variations in knee morphology between the Asian and Western population. Data of Indian knee morphometry of healthy and non osteoarthritic knee was lacking. Objective of this study was to study the knee anthropometry of Indian population and its comparison with other ethnic groups and current TKA Implants. Materials and Methods: 60 patients, 29 female and 31 male with peri-articlar knee injuries from the period of June 2016 to November 2016 were studied. 3D reconstruction of normal knee of the patients undergoing CT scan for injured knee was done. Measurement of the mediolateral width, anteroposterior width and aspect ratio of distal femur and proximal tibia was done. Data was compared with other ethnic groups and currently available and commonly used knee systems. Results: Indian females were found to have significantly (p>0.01) smaller dimensions of femur and tibia than Indian males and both had smaller aspect ratios than the Western population. Also study suggests that there is a morphological mismatch between commonly used implants and Indian knees. Conclusion: Our study suggests that why Western implant mismatches when implanted in Indian patients. Also this study provides definite rationale for designing total knee prosthesis, especially a gender-specific design suitable for the Indian population.

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Tibial Plateau Coverage in Total Knee Arthroplasty

Cited by 71 publications

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Tibial component positioning in total knee arthroplasty: bone coverage and extensor apparatus alignment

Tibial component positioning in total knee arthroplasty: bone coverage and extensor apparatus alignment

Maximizing Tibial Coverage Is Detrimental to Proper Rotational Alignment

Computer tomography 3D reconstruction based study of knee anthropometry of Indian population: Comparison with other ethnic groups and current TKA implants

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