Dataset Information

Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

ABSTRACT:

Background

Rotational alignment of prosthetic components in total knee arthroplasty (TKA) is important to successful outcomes. Component malrotation is a known cause of revision and understanding normal rotational alignment may help recreate normal joint kinematics. To date, no large MRI study assessing femorotibial rotational alignment in nonarthritic knees has been undertaken.

Questions/purposes

Is Insall's tibial axis a reliable rotational landmark against common femoral rotational axes in the nonarthritic patient population?

Methods

We reviewed 544 knee MRI scans performed for suspected soft tissue pathology and identified Insall's tibial rotational axis as well as the femoral clinical trans-epicondylar axis (TEAc), femoral surgical trans-epicondylar axis (TEAs), posterior condylar articular axis (PCA), and a modified Eckhoff's cylindrical axis. The perpendiculars of these axes were superimposed on Insall's tibial axis, and the angular differences were measured.

Results

Insall's axis was internally rotated to the TEAc by 1.4°, externally rotated to Eckhoff's cylindrical axis by 1.8°, externally rotated to the TEAs by 2.7°, and externally rotated to the PCA by 3.5°. The mean deviation from 0° (optimal alignment for each femoral axis) was significantly greater for the PCA relative to all other femoral axis.

Conclusion

Insall's axis is a reliable landmark for rotational positioning of the tibial component and may optimize femorotibial kinematics in fixed-bearing TKA.

SUBMITTER: Wernecke GC

PROVIDER: S-EPMC5026653 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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Publications

Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

Wernecke Gregory C GC Harrris Ian A IA Seeto Bradley G BG Chen Darren B DB MacDessi Samuel J SJ

HSS journal : the musculoskeletal journal of Hospital for Special Surgery 20160222 3

<h4>Background</h4>Rotational alignment of prosthetic components in total knee arthroplasty (TKA) is important to successful outcomes. Component malrotation is a known cause of revision and understanding normal rotational alignment may help recreate normal joint kinematics. To date, no large MRI study assessing femorotibial rotational alignment in nonarthritic knees has been undertaken.<h4>Questions/purposes</h4>Is Insall's tibial axis a reliable rotational landmark against common femoral rotati ...[more]

PMID: 27703414

Similar Datasets

Project description:PurposeThis study was carried out to investigate the accuracy of referring different locations of the patellar tendon attachment site and the geometrical center of the osteotomy surface for tibial rotational alignment and observe the influences of gender differences on the results.MethodsComputed tomography scans of 135 osteoarthritis patients (82 females and 53 males) with varus deformity was obtained to reconstruct three-dimensional (3D) models preoperatively. The medial boundary, medial one-sixth, and medial one-third of the patellar tendon attachment site were marked on the tibia. These points were projected on the tibial osteotomy plane and connected to the geometrical center (GC) of the osteotomy plane or the middle of the posterior cruciate ligament (PCL) to construct six tibial rotational axes (Akagi line, MBPT, MSPT1, MSPT2, MTPT1 and MTPT2). The mismatch angle between the vertical line of the SEA projected on the proximal tibial osteotomy surface and six different reference axes was measured. In additional, the effect of gender differences on rotational alignment for tibial component were assessed.ResultsRelative to the SEA, rotational mismatch angles were - 1.8° ± 5.1° (Akagi line), - 2.5° ± 5.3° (MBPT), 2.8° ± 5.3° (MSPT1), 4.5° ± 5.4° (MSPT2), 7.3° ± 5.4° (MTPT1), and 11.6° ± 5.8° (MTPT2) for different tibial rotational axes in all patients. All measurements differed significantly between the male and female. The tibial rotational axes with the least mean absolute deviation for the female or male were Akagi line or MSPT, respectively. There was no significant difference in whether the GC of the osteotomy surface or the midpoint of PCL termination was chosen as the posterior anatomical landmark when the medial boundary or medial one-sixth point of the patellar tendon attachment site was selected as the anterior anatomical landmark.ConclusionWhen referring patellar tendon attachment site as anterior anatomical landmarks for tibial rotational alignment, the influence of gender difference on the accuracy needs to be taken into account. The geometric center of the tibial osteotomy plane can be used as a substitute for the middle of the PCL termination when reference the medial boundary or medial one-sixth of the patellar tendon attachment site.

Project description:PurposeTo describe a strategy for coronal alignment using a computed tomography (CT) based custom total knee arthroplasty (TKA) system, and to evaluate the agreement between the planned and postoperative Hip-Knee-Ankle (HKA) angle, Femoral Mechanical Angle (FMA) and Tibial Mechanical Angle (TMA).MethodsFrom a consecutive series of 918 primary TKAs, 266 (29%) knees received CT-based posterior-stabilized cemented custom TKA. In addition to a preoperative CT-scan, pre- and post-operative radiographs of weight-bearing long leg, anterior-posterior and lateral views of the knee were obtained, on which the FMA, TMA and HKA angles were measured. CT-based three-dimensional (3D) models enabled to correct for cases with bony wear by referring to the non-worn areas and to estimate the native pre-arthritic angles. The alignment technique aimed to preserve or restore constitutional alignment (CA) within predetermined limits, by defining a 'target zone' based on three criteria: 1) a ± 3° (range 87°-93°) primary tolerance for the femoral and tibial resections; 2) a ± 2° secondary tolerance for component obliquity, extending the bounds for FMA and TMA (range 85°-95°); 3) a planned HKA angle range of 175°-183°. Agreement between preoperative, planned and postoperative measurements of FMA, TMA and HKA angle were calculated using intra-class correlation coefficients (ICC).ResultsPreoperative radiograph and CT-scan measurements revealed that, respectively, 73 (28%) and 103 (40%) knees were in the 'target zone', whereas postoperative radiographs revealed that 217 (84%) TKAs were in the 'target zone'. Deviation from the planned angles were - 0.5° ± 1.8° for FMA, - 0.5° ± 1.8° for TMA, and - 1.1° ± 2.1° for HKA angle. Finally, the agreement between the planned and achieved targets, indicated by ICC, were good for FMA (0.701), fair for TMA (0.462) and fair for HKA angle (0.472).ConclusionUsing this strategy for coronal alignment, 84% of custom TKAs were within the 'target zone' for FMA, TMA and HKA angles. These findings support the concepts of emerging personalized medicine technologies, and emphasise the importance of accurate strategies for preoperative planning, which are key to achieving satisfactory 'personalised alignment' that can further be improved by customisation of implant components.Level of evidenceIV.

Dataset Information

Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

Background

Questions/purposes

Methods

Results

Conclusion

Publications

Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

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