Knee Surg Sports Traumatol Arthrosc DOI 10.1007/s00167-014-3170-7
Knee
Fibular axes are not a reliable landmark for tibial mechanical axes of osteoarthritic knees that underwent total knee arthroplasty Yuichi Kuroda · Kazunari Ishida · Tomoyuki Matsumoto · Hiroshi Sasaki · Tokio Matsuzaki · Shinya Oka · Koji Takayama · Katsumasa Tei · Takehiko Matsushita · Nobuhiro Tsumura · Ryosuke Kuroda · Masahiro Kurosaka
Received: 24 January 2014 / Accepted: 3 July 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The sagittal fibular axis serves as an intra-operative landmark during conventional total knee arthroplasty (TKA); however, only a few relevant anatomical studies have been published regarding its use as an extramedullary guide. Furthermore, the correlation between the coronal fibular and tibial mechanical axes in osteoarthritic knees has been only reported once. Here, the hypothesis of this study is that the fibula can be a reliable intra-operative landmark, in the sagittal and coronal planes, among patients with osteoarthritis who have undergone TKA. Methods Osteoarthritic knees (n = 62) after TKA were evaluated using three-dimensional image-matching software. The angles between the tibial mechanical axis and the fibular shaft axis were measured in the sagittal and coronal planes. Moreover, correlations between the angles and patient-specific factors were evaluated. Results The mean angle between the tibial mechanical and fibular shaft axes was 2.6° ± 2.3° for posterior
inclination in the sagittal plane and 0.9° ± 2.0° for varus inclination in the coronal plane. The percentage of subjects with the fibular shaft axis within 2° of the tibial mechanical axis was 17.7 and 69.3 % in the sagittal and coronal planes, respectively. No patient-specific factors were correlated with the angle between the tibial mechanical and fibular shaft axes. Conclusions The angle between the tibial mechanical and fibular shaft axes differed among patients, independent of patient-specific factors, and did not appear to be a reliable intra-operative landmark. Surgeons should use values from individual pre-operative evaluations of the axis as reference for conventional TKA. Level of evidence Case series with no comparison group, Level IV. Keywords Total knee arthroplasty · Fibula axis · Surgical technique · Anatomical landmark · Tibial slope
Introduction Y. Kuroda · N. Tsumura Department of Orthopaedic Surgery, Hyogo Rehabilitation Center Hospital, Kobe, Japan K. Ishida (*) · H. Sasaki Department of Orthopaedic Surgery, Kobe Kaisei Hospital, 3‑11‑15, Shinohara‑Kita, Nada, Kobe 657‑0068, Japan e-mail: [email protected] T. Matsumoto · T. Matsuzaki · S. Oka · K. Takayama · T. Matsushita · R. Kuroda · M. Kurosaka Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan K. Tei Department of Orthopaedic Surgery, Chibune General Hospital, Osaka, Japan
Total knee arthroplasty (TKA) is a well-established surgical procedure that generally results in pain relief, improved physical function, and a high level of patient satisfaction. The long-term survivorship of TKA depends on the appropriate alignment of the limb and positioning of the prosthetic components. The analyses of coronal and tibiofemoral rotational alignments after TKA have been previously reported [10, 11, 16]. In the sagittal alignment, the posterior tibial slope affects anteroposterior stability, range of motion, and contact pressure within the tibiofemoral joint [3, 9]; an inappropriate angle results in polyethylene wear, component loosening, and posterior cruciate ligament strain [2, 8, 22].
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It is unclear whether an intra-medullary or extra-medullary alignment guide is more appropriate for the tibial sector in conventional TKA [4]. The use of extramedullary guides prevents potential complications associated with intra-medullary guides, such as fat embolization, intra-operative fracture, loss of polymethyl methacrylate pressurization, and inability of intra-medullary rod passage because of deformity, retained hardware, or pathologic bone disease [6]. However, it is not easy to align an extramedullary guide to the mechanical axis because the centre of the ankle is difficult to locate [21]. Although a number of tendon and soft tissue landmarks have been recommended to avoid this problem [15, 17, 19], most of these landmarks are affected by the ankle joint position [13]. The sagittal fibular axis, a landmark for the tibial mechanical axis [7, 12, 18, 21], is usually not affected by the ankle joint position. Therefore, the fibular axis is considered to be one of the most reliable landmarks for the tibial sagittal mechanical axis. However, only a few relevant threedimensional anatomical studies have been published [7, 18, 21]. Furthermore, the correlation between the coronal fibula and tibial mechanical axes in osteoarthritic knees has been reported in only one study [21]. Therefore, the accuracy of using the fibular axis as a landmark for TKA is currently unknown. The hypothesis of this study is that the fibula can be a reliable intra-operative landmark, in the sagittal and coronal planes, for patients with osteoarthritis who are undergoing TKA and are evaluated by three-dimensional imagematching software system. We hope that our study findings will increase the surgeons’ understanding of the relationship between fibula and tibial mechanical axes, which can minimize technical errors during surgery and optimize alignment during TKA.
Materials and methods From 2010 to 2013, 62 osteoarthritic knees in 48 female and 14 male subjects who underwent TKA (20 knees: P.F.C Sigma, DePuy Orthopaedics, Inc., Warsaw, IN; 22 knees: e-motion, Aesculap Inc., Centre Valley, PA; 20 knees: Triathlon, Stryker Orthopaedics, Mahwah, NJ) were evaluated. A posterior-stabilizing prosthesis and a cruciate-retaining implant were used in 50 and 12 knees, respectively. Patients who had a history of trauma, infection, tumour, rheumatoid disorder, or congenital disorder were excluded from the study. Moreover, cases of malaligned positioning and inappropriate rotation of the prosthetic components were excluded. The mean age of the subjects was 77.3 ± 6.7 years (mean ± SD). The average height and weight were 151.1 ± 7.3 cm and 58.5 ± 10.5 kg,
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Knee Surg Sports Traumatol Arthrosc
respectively. All the enrolled subjects experienced clinical success. Details regarding the use of the Athena Knee® threedimensional image-matching software (SoftCube Co, Ltd, Osaka, Japan) have been described previously [5, 20]. Briefly, a three-dimensional marker was attached to the surface of the patient’s lower leg 1 month post-operatively, and the silhouettes of the marker on the images were used for three-dimensional coupling of the two radiographic images (anteroposterior and lateral views) (Fig. 1a). Thereafter, the implanted components were matched to the images using a computer-aided design program (Fig. 1b). In addition, pre-operatively computed tomography (CT) images were matched to the coupled radiographic images (Fig. 1c). Then, the angles between the tibial mechanical and fibular shaft axes were measured on the sagittal and coronal planes using the Athena Knee software. The sagittal and coronal planes were expressed as the anteroposterior and lateral views towards the prosthesis. The tibial mechanical axis was defined as a straight line from the centre of the appropriately sized tibial component to the centre of the distal tibial plafond [21]. The fibular shaft axis was measured as a line connecting the centre of the fibular head to the centre of the lateral malleolus because the fibular head and lateral malleolus were easily palpable intra-operatively (Fig. 2) [21]. Furthermore, correlations between the angle of the tibial mechanical and fibular shaft axes and patient-specific factors (i.e. height, weight, tibial length, fibular length, and tibial torsion) were examined. Tibial length was measured from the top of the eminentia intercondylaris to the ankle joint (Fig. 3a); fibular length was measured from the top of the fibular head to the distal end of the lateral malleolus (Fig. 3b). Tibial torsion was defined as the angle between the Akagi line [1] and the line perpendicular to the transmalleolar axis. The transmalleolar axis was defined as the line connecting the tips of the medial and lateral malleoli. An angle within 2° of the mechanical axis was defined as an outlier. This study was approved by the institutional review board at Kobe Kaisei Hospital (identification number: 0047). Statistical analysis The results were statistically analysed using a statistical software package (Statview 5.0, Abacus Concepts Inc, Berkeley, CA, USA). The angle between the tibial mechanical and fibular shaft axes were evaluated at least 3 times in each patient by 3 different investigators and then averaged. Intra-class correlation coefficients were used to measure intra- and inter-observer reliability. Pearson’s correlation coefficient tests were used to examine how the angle between the tibial mechanical and fibular shaft axes, in the sagittal and coronal planes, correlates with the
Knee Surg Sports Traumatol Arthrosc
Fig. 1 Athena Knee—a three-dimensional (3-D) digital template software. A 3-D marker was attached to the surface of the patient’s lower leg, and the silhouettes of the marker on the images were used for 3-D coupling of the 2 radiographic images (a). The implanted
components were matched to the images using a computer-aided design program (b). Computed tomography images obtained preoperatively were matched to the coupled radiographic images (c)
patient-specific factors. A P value of
Knee
Fibular axes are not a reliable landmark for tibial mechanical axes of osteoarthritic knees that underwent total knee arthroplasty Yuichi Kuroda · Kazunari Ishida · Tomoyuki Matsumoto · Hiroshi Sasaki · Tokio Matsuzaki · Shinya Oka · Koji Takayama · Katsumasa Tei · Takehiko Matsushita · Nobuhiro Tsumura · Ryosuke Kuroda · Masahiro Kurosaka
Received: 24 January 2014 / Accepted: 3 July 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The sagittal fibular axis serves as an intra-operative landmark during conventional total knee arthroplasty (TKA); however, only a few relevant anatomical studies have been published regarding its use as an extramedullary guide. Furthermore, the correlation between the coronal fibular and tibial mechanical axes in osteoarthritic knees has been only reported once. Here, the hypothesis of this study is that the fibula can be a reliable intra-operative landmark, in the sagittal and coronal planes, among patients with osteoarthritis who have undergone TKA. Methods Osteoarthritic knees (n = 62) after TKA were evaluated using three-dimensional image-matching software. The angles between the tibial mechanical axis and the fibular shaft axis were measured in the sagittal and coronal planes. Moreover, correlations between the angles and patient-specific factors were evaluated. Results The mean angle between the tibial mechanical and fibular shaft axes was 2.6° ± 2.3° for posterior
inclination in the sagittal plane and 0.9° ± 2.0° for varus inclination in the coronal plane. The percentage of subjects with the fibular shaft axis within 2° of the tibial mechanical axis was 17.7 and 69.3 % in the sagittal and coronal planes, respectively. No patient-specific factors were correlated with the angle between the tibial mechanical and fibular shaft axes. Conclusions The angle between the tibial mechanical and fibular shaft axes differed among patients, independent of patient-specific factors, and did not appear to be a reliable intra-operative landmark. Surgeons should use values from individual pre-operative evaluations of the axis as reference for conventional TKA. Level of evidence Case series with no comparison group, Level IV. Keywords Total knee arthroplasty · Fibula axis · Surgical technique · Anatomical landmark · Tibial slope
Introduction Y. Kuroda · N. Tsumura Department of Orthopaedic Surgery, Hyogo Rehabilitation Center Hospital, Kobe, Japan K. Ishida (*) · H. Sasaki Department of Orthopaedic Surgery, Kobe Kaisei Hospital, 3‑11‑15, Shinohara‑Kita, Nada, Kobe 657‑0068, Japan e-mail: [email protected] T. Matsumoto · T. Matsuzaki · S. Oka · K. Takayama · T. Matsushita · R. Kuroda · M. Kurosaka Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan K. Tei Department of Orthopaedic Surgery, Chibune General Hospital, Osaka, Japan
Total knee arthroplasty (TKA) is a well-established surgical procedure that generally results in pain relief, improved physical function, and a high level of patient satisfaction. The long-term survivorship of TKA depends on the appropriate alignment of the limb and positioning of the prosthetic components. The analyses of coronal and tibiofemoral rotational alignments after TKA have been previously reported [10, 11, 16]. In the sagittal alignment, the posterior tibial slope affects anteroposterior stability, range of motion, and contact pressure within the tibiofemoral joint [3, 9]; an inappropriate angle results in polyethylene wear, component loosening, and posterior cruciate ligament strain [2, 8, 22].
13
It is unclear whether an intra-medullary or extra-medullary alignment guide is more appropriate for the tibial sector in conventional TKA [4]. The use of extramedullary guides prevents potential complications associated with intra-medullary guides, such as fat embolization, intra-operative fracture, loss of polymethyl methacrylate pressurization, and inability of intra-medullary rod passage because of deformity, retained hardware, or pathologic bone disease [6]. However, it is not easy to align an extramedullary guide to the mechanical axis because the centre of the ankle is difficult to locate [21]. Although a number of tendon and soft tissue landmarks have been recommended to avoid this problem [15, 17, 19], most of these landmarks are affected by the ankle joint position [13]. The sagittal fibular axis, a landmark for the tibial mechanical axis [7, 12, 18, 21], is usually not affected by the ankle joint position. Therefore, the fibular axis is considered to be one of the most reliable landmarks for the tibial sagittal mechanical axis. However, only a few relevant threedimensional anatomical studies have been published [7, 18, 21]. Furthermore, the correlation between the coronal fibula and tibial mechanical axes in osteoarthritic knees has been reported in only one study [21]. Therefore, the accuracy of using the fibular axis as a landmark for TKA is currently unknown. The hypothesis of this study is that the fibula can be a reliable intra-operative landmark, in the sagittal and coronal planes, for patients with osteoarthritis who are undergoing TKA and are evaluated by three-dimensional imagematching software system. We hope that our study findings will increase the surgeons’ understanding of the relationship between fibula and tibial mechanical axes, which can minimize technical errors during surgery and optimize alignment during TKA.
Materials and methods From 2010 to 2013, 62 osteoarthritic knees in 48 female and 14 male subjects who underwent TKA (20 knees: P.F.C Sigma, DePuy Orthopaedics, Inc., Warsaw, IN; 22 knees: e-motion, Aesculap Inc., Centre Valley, PA; 20 knees: Triathlon, Stryker Orthopaedics, Mahwah, NJ) were evaluated. A posterior-stabilizing prosthesis and a cruciate-retaining implant were used in 50 and 12 knees, respectively. Patients who had a history of trauma, infection, tumour, rheumatoid disorder, or congenital disorder were excluded from the study. Moreover, cases of malaligned positioning and inappropriate rotation of the prosthetic components were excluded. The mean age of the subjects was 77.3 ± 6.7 years (mean ± SD). The average height and weight were 151.1 ± 7.3 cm and 58.5 ± 10.5 kg,
13
Knee Surg Sports Traumatol Arthrosc
respectively. All the enrolled subjects experienced clinical success. Details regarding the use of the Athena Knee® threedimensional image-matching software (SoftCube Co, Ltd, Osaka, Japan) have been described previously [5, 20]. Briefly, a three-dimensional marker was attached to the surface of the patient’s lower leg 1 month post-operatively, and the silhouettes of the marker on the images were used for three-dimensional coupling of the two radiographic images (anteroposterior and lateral views) (Fig. 1a). Thereafter, the implanted components were matched to the images using a computer-aided design program (Fig. 1b). In addition, pre-operatively computed tomography (CT) images were matched to the coupled radiographic images (Fig. 1c). Then, the angles between the tibial mechanical and fibular shaft axes were measured on the sagittal and coronal planes using the Athena Knee software. The sagittal and coronal planes were expressed as the anteroposterior and lateral views towards the prosthesis. The tibial mechanical axis was defined as a straight line from the centre of the appropriately sized tibial component to the centre of the distal tibial plafond [21]. The fibular shaft axis was measured as a line connecting the centre of the fibular head to the centre of the lateral malleolus because the fibular head and lateral malleolus were easily palpable intra-operatively (Fig. 2) [21]. Furthermore, correlations between the angle of the tibial mechanical and fibular shaft axes and patient-specific factors (i.e. height, weight, tibial length, fibular length, and tibial torsion) were examined. Tibial length was measured from the top of the eminentia intercondylaris to the ankle joint (Fig. 3a); fibular length was measured from the top of the fibular head to the distal end of the lateral malleolus (Fig. 3b). Tibial torsion was defined as the angle between the Akagi line [1] and the line perpendicular to the transmalleolar axis. The transmalleolar axis was defined as the line connecting the tips of the medial and lateral malleoli. An angle within 2° of the mechanical axis was defined as an outlier. This study was approved by the institutional review board at Kobe Kaisei Hospital (identification number: 0047). Statistical analysis The results were statistically analysed using a statistical software package (Statview 5.0, Abacus Concepts Inc, Berkeley, CA, USA). The angle between the tibial mechanical and fibular shaft axes were evaluated at least 3 times in each patient by 3 different investigators and then averaged. Intra-class correlation coefficients were used to measure intra- and inter-observer reliability. Pearson’s correlation coefficient tests were used to examine how the angle between the tibial mechanical and fibular shaft axes, in the sagittal and coronal planes, correlates with the
Knee Surg Sports Traumatol Arthrosc
Fig. 1 Athena Knee—a three-dimensional (3-D) digital template software. A 3-D marker was attached to the surface of the patient’s lower leg, and the silhouettes of the marker on the images were used for 3-D coupling of the 2 radiographic images (a). The implanted
components were matched to the images using a computer-aided design program (b). Computed tomography images obtained preoperatively were matched to the coupled radiographic images (c)
patient-specific factors. A P value of
