The effect of valgus/varus malalignment on load distribution in total knee replacements

Werner, Frederick W.; Ayers, David C.; Maletsky, Lorin P.; Rullkoetter, Paul J.

doi:10.1016/j.jbiomech.2004.02.024

Cited by 258 publications

(151 citation statements)

References 7 publications

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“…First, our definition of varus malalignment and criteria for potential indication of high tibial osteotomy were set arbitrarily. However, our cut-off value for varus malalignment, ie, varus 5°of the mechanical tibiofemoral angle or 25% of the weight loading line, was biomechanically meaningful, as more varus alignments than these are known to adversely affect tibiofemoral mechanics and pressure distribution on the knee [24]. Moreover, several clinical studies have used similar cut-off values for varus malalignment and indication for high tibial osteotomy [2,9,11,16,21].…”

Section: Discussionmentioning

confidence: 98%

Coronal Limb Alignment and Indications for High Tibial Osteotomy in Patients Undergoing Revision ACL Reconstruction

Won

Chang

et al. 2013

Clinical Orthopaedics &Amp; Related Research

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Background Failed ACL reconstruction frequently is accompanied by irreparable medial meniscal tear and/or visible osteoarthritis (OA) in the medial tibiofemoral joint. Thus, assessment for the presence of varus malalignment is important in caring for patients in whom revision ACL reconstruction is considered. Questions/purposesWe determined whether patients undergoing revision ACL reconstruction (1) have more frequent varus malalignment coupled with more severe degrees of medial meniscal injury and/or medial tibiofemoral OA, and (2) would meet potential indications for high tibial osteotomy more frequently than patients undergoing primary ACL reconstruction. Methods We compared 58 patients undergoing revision ACL reconstruction and 116 patients undergoing primary ACL reconstruction. The mechanical tibiofemoral angle and the weight loading line (%) of the knee were measured. Additionally, radiographic degrees of OA in the tibiofemoral joints, and meniscal conditions were assessed. Then, proportions of potential candidates for high tibial osteotomy between the two groups were compared based on the following indications: (1) weight loading line less than 5%, (2) weight loading line less than 25% and medial tibiofemoral OA Kellgren-Lawrence Grade 3 or greater, or (3) weight loading line less than 25% and Kellgren-Lawrence Grade 2 medial tibiofemoral OA plus subtotal or total medial meniscectomy status. Results The revision ACL reconstruction group had more frequent varus malalignment in terms of proportion of knees with more varus mechanical tibiofemoral angle than varus 5°(19% versus 8%, p = 0.029) and knees with weight loading line less than 25% (22% versus 9%, p = 0.011). This group also had more frequent high-grade injury of the medial meniscus (34% versus 16%, p = 0.007) and tended to have more frequent higher-grade radiographic OA at the medial tibiofemoral joint (19% versus 9%, p = 0.076). The percentage of patients meeting potential indications for high tibial osteotomy was greater in this group (14% versus 2%, p = 0.003). Conclusions We found that many patients undergoing revision ACL surgery may be reasonable candidates for concurrent high tibial osteotomy to address concomitant alignment and OA issues in the medial compartment. However, whether that additional intervention is offset by added risk and morbidity should be the focus of a future study, as it cannot be answered by a study of this design.

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Section: Discussionmentioning

confidence: 98%

Coronal Limb Alignment and Indications for High Tibial Osteotomy in Patients Undergoing Revision ACL Reconstruction

Won

Chang

et al. 2013

Clinical Orthopaedics &Amp; Related Research

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“…Recently, a study by Parratte et al [15] reported an alignment outside 3°of the normal mechanical axis does not successfully predict a poor-functioning TKA in a series of patients. While mechanical alignment is important, there are multiple surgically controllable variables involved in producing a successful TKA, including coronal, transverse, and sagittal plane soft tissue stability [1,4,6,17,21]. Also, in some varus knees, there are individuals who have a large adductor moment, which predicts failures in patients receiving high tibial osteotomy [16], but there is no similar study showing where muscle forces are mapped out that predicts a higher failure rate in TKA.…”

Section: Discussionmentioning

confidence: 99%

“…Barrack et al [2] reported the presence and severity of femoral component internal rotation correlated with patellofemoral complications. In a cadaveric study, Werner et al [21] found varus/valgus malalignment altered tibiofemoral load distribution. Furthermore, in a retrieval analysis, Wasielewski et al [20] identified specific wear patterns contributing to implant failure and their relationship to technical aspects in TKA.…”

Section: Introductionmentioning

confidence: 98%

How Does TKA Kinematics Vary With Transverse Plane Alignment Changes in a Contemporary Implant?

Mihalko

Conner

Benner

et al. 2012

Clinical Orthopaedics &Amp; Related Research

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Background Assessment of patient function after TKA often focuses on implant alignment and daily activity capabilities, but the functional results and kinematics of the TKA are not easily predicted by some of these parameters during surgery. Questions/purposes We asked whether differences in implant alignment in the transverse plane may affect fluorokinematics and be one of the many variables that help explain the discrepancies in fluorokinematic results. Methods We utilized a computer model (LifeMOD TM / KneeSIM; LifeModeler, Inc, San Clemente, CA, USA) to show variability in polyethylene contact patterns. We imported components of a cruciate-retaining TKA into the model and subjected the systems to a simulated lunge. We modeled five different combinations of implant positioning in the transverse plane of both the femoral and tibial components in internal or external rotation and compared the resulting changes in joint rotations and displacements of these five variations to those for published fluorokinematic observations using the same modeled lunge-type maneuver for five patients. Results We observed variations in AP translation of the lateral and medial femoral condyles resembling several of those in the literature for individual patients with the same cruciate-retaining knee implant. The largest AP translational changes were seen with the tibia internally rotated 5°. Using the five different implant transverse plane alignment scenarios resulted in a coefficient of determination of 0.6 for the linear regression when compared to five subjects from a published fluorokinematic study. Conclusions Variations in implant positioning may be responsible for variations in fluorokinematics reported for individual subjects with the same implant design. Clinical Relevance If validated computer modeling can aid surgeons to predict the effects of individual implant alignment variations in TKA kinematics, a more personalized approach to implant positioning during TKA can be implemented.

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“…However, in instances where incorrect positioning and malignment of the TKA components are observed, patients can experience a range of negative postoperative outcomes such as loss of thickness of polyethylene tibial bearings, eccentric loading, implant loosening, and eventual early revision [10,35,36,39,43]. To avoid these complications, achieving a postoperative alignment within the range of 0°±3°of the mechanical axis is recommended [20,33].…”

Section: Introductionmentioning

confidence: 99%

A comparison of conventional and patient-specific instruments in total knee arthroplasty

Daniilidis

Tibesku

2013

International Orthopaedics (SICOT)

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Purpose Several authors have observed that standard instrumentation (SI) may be insufficient for addressing component malalignment. Patient-matched cutting blocks (PMCB) technology was introduced to improve surgeons' ability to achieve a neutral postoperative mechanical axis following total knee arthroplasty (TKA). The current retrospective study was designed to compare the ability of SI and PMCB to achieve a hip-knee-ankle angle (HKA) within ±3°of the ideal alignment of 180°. Methods Between October 2009 and December 2012, 170 TKAs in 166 patients (four bilateral) using VISIONAIRE (Smith & Nephew) PMCB technology were performed. Additionally, 160 TKAs in 160 consecutive patients that had received a total knee arthroplasty using SI during the same time period were used as a control group, All surgeries were performed by the same surgeon. Standardized pre-and postoperative long-leg standing x-rays were retrospectively evaluated to compare the two patient cohorts. Results X-rays were available for analysis for 156 knees in the SI group and 150 in the PMCB group. The average postsurgical HKA was 178.7±2.5 in the SI group and 178.4±1.5 in the PMCB group. However, the rate of±3°outliers was 21.2 % in the SI group and 9.3 % in the PMCB group. There were no intraoperative complications with the use of PMCB technology or SI. Conclusions PMCB technology proved superior to conventional instrumentation in achieving a neutral mechanical axis following TKA. Further follow-up will be needed to ascertain the long-term impact of these findings.

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The effect of valgus/varus malalignment on load distribution in total knee replacements

Cited by 258 publications

References 7 publications

Coronal Limb Alignment and Indications for High Tibial Osteotomy in Patients Undergoing Revision ACL Reconstruction

Coronal Limb Alignment and Indications for High Tibial Osteotomy in Patients Undergoing Revision ACL Reconstruction

How Does TKA Kinematics Vary With Transverse Plane Alignment Changes in a Contemporary Implant?

A comparison of conventional and patient-specific instruments in total knee arthroplasty

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