Influence of the posterior tibial slope on the flexion gap in total knee arthroplasty.
Okazaki Ken,Tashiro Yasutaka,Mizu-uchi Hideki,Hamai Satoshi,Doi Toshio,Iwamoto Yukihide
The Knee
BACKGROUND:Adjusting the joint gap length to be equal in both extension and flexion is an important issue in total knee arthroplasty (TKA). It is generally acknowledged that posterior tibial slope affects the flexion gap; however, the extent to which changes in the tibial slope angle directly affect the flexion gap remains unclear. This study aimed to clarify the influence of tibial slope changes on the flexion gap in cruciate-retaining (CR) or posterior-stabilizing (PS) TKA. METHODS:The flexion gap was measured using a tensor device with the femoral trial component in 20 cases each of CR- and PS-TKA. A wedge plate with a 5° inclination was placed on the tibial cut surface by switching its front-back direction to increase or decrease the tibial slope by 5°. The flexion gap after changing the tibial slope was compared to that of the neutral slope measured with a flat plate that had the same thickness as that of the wedge plate center. RESULTS:When the tibial slope decreased or increased by 5°, the flexion gap decreased or increased by 1.9 ± 0.6mm or 1.8 ± 0.4mm, respectively, with CR-TKA and 1.2 ± 0.4mm or 1.1 ± 0.3mm, respectively, with PS-TKA. CONCLUSIONS:The influence of changing the tibial slope by 5° on the flexion gap was approximately 2mm with CR-TKA and 1mm with PS-TKA. CLINICAL RELEVANCE:This information is useful when considering the effect of manipulating the tibial slope on the flexion gap when performing CR- or PS-TKA.
10.1016/j.knee.2014.02.019
Review article: knee flexion after total knee arthroplasty.
Chiu K Y,Ng T P,Tang W M,Yau W P
Journal of orthopaedic surgery (Hong Kong)
Many factors affect or predict the flexion range achieved after total knee arthroplasty. While the knees that have good preoperative flexion have better final flexion, knees with good preoperative flexion do lose some flexion whereas those with poor preoperative flexion can gain flexion. Although studies of different prosthetic designs have produced conflicting results, recent studies appear to favour posterior cruciate ligament (PCL)--substituting over PCL-retaining prostheses. Several factors related to surgical techniques have been found to be important. These include the tightness of the retained posterior cruciate ligament, the elevation of the joint line, increased patellar thickness, and a trapezoidal flexion gap. Vigorous rehabilitation after surgery appears useful, while continuous passive motion has not been found to be effective. Obesity and previous surgery are poor prognostic factors; certain cultural factors, such as the Japanese style of sitting, offer 'unintentional' passive flexion and result in patients with better range. If the flexion after surgery is unsatisfactory, manipulation under anaesthesia within 3 months of the total knee arthroplasty can be beneficial.
10.1177/230949900201000215
Functionally aligned total knee arthroplasty: A lateral flexion laxity up to 6 mm is safe!
Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA
PURPOSE:Loose flexion gaps are associated with poor functional outcomes and instability in total knee arthroplasty (TKA). The effect of a trapezoidal flexion gap in a functionally aligned TKA remains unknown. The aim of this study was to investigate the effect of a larger lateral flexion gap in a robotic-assisted (RA), functionally aligned (FA) and cruciate-retaining (CR) TKA on clinical outcomes. METHODS:Data from 527 TKA in 478 patients from 2018 to 2020 were collected. All patients underwent an RA (MAKO, Stryker), FA and CR TKA. Gap measurements were collected intraoperatively. Patient-reported outcome measures (PROMs), pain Visual analogue score (VAS) and range of motion were collected postoperatively. Patients were also asked about the ease of stair ascent and descent and kneeling on a 5-point scale. The minimum follow-up was 2 years. Patients were stratified into three groups based on lateral flexion laxity. RESULTS:At 2 years postoperatively, the group with a looser gap (3-6 mm) had higher mean PROMs when compared with the group with a gap of 2-3 mm. There were no differences detected in any other outcomes at 2 years. A total of 70.9% of patients in the group with a 3-6 mm gap reported being able to walk down a flight of stairs 'easily', compared with 56.7% in the 2-3 mm group and 54% in the <2 mm group (p = 0.04). CONCLUSION:The study shows that a loose lateral flexion gap in functionally aligned CR TKA does not adversely affect outcomes in the short term. LEVEL OF EVIDENCE:Level III, retrospective cohort study.
10.1002/ksa.12087
Flexion gap stabilization by oversizing posterior condylar offset in deep-dished total knee replacement does not compromise flexion: A single-surgeon, retrospective, observational, mid-term series.
Massin Philippe,Lefevre Edouard,Serane Julien
Orthopaedics & traumatology, surgery & research : OTSR
INTRODUCTION:In total knee replacement surgery, medio-lateral knee balancing is recognized as the key to achieving satisfactory functional results. But it may not be enough to stabilize the flexion gap using deep-dished implants. We achieved flexion gap balance by oversizing the femoral component, thus increasing the posterior condylar offset (PCO). The purpose of this study was to describe the applicability of this technique and to test whether it produced adverse effects on medium-term outcomes. We hypothesized that it would not compromise the results if used properly. We therefore asked: (1) at how many cases of flexion gap balance would require oversizing the femoral component; (2) if femoral components oversizing would modify the mid-term results as per forgotten joint score (FJS) scores and whether flexion gain would be comparable to patients in whom it was not increased. MATERIALS AND METHODS:Ninety-four patients (120 knees) were operated between September 2009 and 2011 (age 68±9 years) using the cementless Hyperflex version of the Natural Knees (Zimmer, Warsaw, IN, USA). Postero stabilization was achieved using deep-dished inserts. The Gender configuration has provided narrow inserts to better adapt the female anatomy. A special navigation system measured the displacement of the lateral and medial femoro-tibial contact points with infra-millimetric precision. Adopting a tibial cut first, gap-balancing technique with anterior referencing, the decision to oversize the femoral component relied on the 90° flexion drawer test, which showed more than 6mm sagittal laxity before the femoral bone cuts. Eighty-one (105 knees) patients were reviewed with average 63±27-month follow-up. RESULTS:Femoral components were augmented by 1 size in 60 cases and by 2 sizes in 7 cases. At final review, knees with an oversized femoral component (60) achieved the same results as those implanted with a non-oversized femoral component (n=45) in terms of mean flexion gain (-5°±34 versus -4°±23, p=0.78), mean FJS (63±26 versus 61±23; p=0.56). CONCLUSION:Balancing the Flexion gap by oversizing the femoral component did not compromise flexion range and functional results. LEVEL OF EVIDENCE:IV, Retrospective cohort study.
10.1016/j.otsr.2019.04.008
Flexion Instability After Total Knee Arthroplasty.
Stambough Jeffrey B,Edwards Paul K,Mannen Erin M,Barnes C Lowry,Mears Simon C
The Journal of the American Academy of Orthopaedic Surgeons
Flexion instability after total knee arthroplasty (TKA) is caused by an increased flexion gap compared with extension gap. Patients present with recurrent effusions, subjective instability (especially going downstairs), quadriceps weakness, and diffuse periretinacular pain. Manual testing for laxity in flexion is commonly done to confirm a diagnosis, although testing positions and laxity grades are inconsistent. Nonsurgical treatment includes quadriceps strengthening and bracing treatment. The mainstays to surgical management of femoral instability involve increasing the posterior condylar offset, decreasing the tibial slope, raising the joint line in combination with a thicker polyethylene insert, and ensuring appropriate rotation of implants. Patient outcomes after revision TKA for flexion instability show the least amount of improvement when compared with revisions for other TKA failure etiologies. Future work is needed to unify reproducible diagnostic criteria. Advancements in biomechanical analysis with motion detection, isokinetic quadriceps strength testing, and computational modeling are needed to advance the collective understanding of this underappreciated failure mechanism.
10.5435/JAAOS-D-18-00347
The effect of ankle rotation on cutting of the tibia in total knee arthroplasty.
Mizu-uchi Hideki,Matsuda Shuichi,Miura Hiromasa,Higaki Hidehiko,Okazaki Ken,Iwamoto Yukihide
The Journal of bone and joint surgery. American volume
BACKGROUND:Extramedullary alignment guides are commonly used to prepare the tibia during total knee arthroplasty. One disadvantage is that the guide is easily affected by the position of the ankle joint. The tibia may have a rotational mismatch between its proximal and distal ends. We hypothesized that a rotational mismatch might cause incorrect positioning of an extramedullary alignment guide and evaluated such a mismatch on the predicted postoperative coronal alignment of the tibia. METHODS:Fifty-three osteoarthritic knees with varus deformity in fifty-one patients were evaluated with use of computerized tomography scans before total knee arthroplasty. We defined one anteroposterior axis of the ankle joint and five different anteroposterior axes of the proximal aspect of the tibia using three-dimensional bone models from the computerized tomography data. We measured the rotational angle between the anteroposterior axis of the ankle joint and the proximal part of the tibia. The distal end of the extramedullary guide was placed in front of the center of the ankle joint (on the line of the extended anteroposterior axis of the ankle joint), and the proximal end was placed on the line of the extended anteroposterior axis of the proximal part of the tibia. We established spatial coordinates to evaluate the effect of the rotational angle on the predicted postoperative coronal alignment of the tibia and calculated the presumed tibial coronal alignment. RESULTS:The rotational angle was positive (3.6 degrees to 19.7 degrees) for all of the anteroposterior axes of the proximal aspect of the tibia, indicating that the ankle joint was externally rotated relative to the proximal part of the tibia. The predicted tibial coronal alignment was varus (0.5 degrees to 5.1 degrees) for all of the anteroposterior axes of the proximal part of the tibia. CONCLUSIONS:When an extramedullary alignment guide is used to prepare the tibia in total knee arthroplasty, varus alignment of the tibial component can occur because of a rotational mismatch between the proximal part of the tibia and the ankle joint.
10.2106/JBJS.E.01288
The Posterolateral Corner-Locked Technique Is Applicable in a Chinese Population Regarding the Tibial Component Rotation Alignment in Total Knee Arthroplasty.
Fang Chao-Hua,Cheng Cheng-Kung,Qu Tie-Bing,Zhang Jun-Hui,Zhang Bo,Hua Qun,Yan Shi-Gui
The journal of knee surgery
Rotational malalignment between the femoral and tibial components in total knee arthroplasty (TKA) can affect clinical outcomes, but there is no consensus on how to best determine tibia tray orientation. The posterolateral corner-locked (PLCL) technique may be a new method. This study aims to assess the applicability of this technique in a Chinese population. Forty normal Chinese volunteers were recruited and underwent computed tomography (CT) of the lower limbs. Knee model reconstructions and simulated standard tibial osteotomy were conducted digitally. The transepicondylar axis (TEA), the Akagi line, and the line connecting the medial third of the tibial tubercle with the midpoint of the posterior cruciate ligament (PCL) were projected to the tibial cross-section and marked. The PLCL technique was applied using either symmetrical or asymmetrical tibial tray templates, and the anteroposterior (AP) axis of the tibial tray was marked. The angles between the TEA and these lines were calculated, and the statistical differences were analyzed. The angle between the TEA and the Akagi line and between the TEA and the line connecting the medial third of the tibial tubercle with the midpoint of the PCL were 96.90 ± 5.57 and 107.31 ± 5.95 degrees, respectively. The angles between the TEA and the AP axis of the symmetrical and the asymmetrical design tibial trays were 94.01 ± 4.21 and 96.65 ± 4.70 degrees, respectively. Except for the Akagi line and AP axis of the asymmetrical tibial tray, statistical differences were found between all lines ( < 0.05). The PLCL technique is principally suitable for Chinese patients requiring TKA when using the tibial component referred to in this study, although it may result in slight external rotation.
10.1055/s-0039-1678536
Rotational references for total knee arthroplasty tibial components change with level of resection.
Graw Bradley P,Harris Alexander H,Tripuraneni Krishna R,Giori Nicholas J
Clinical orthopaedics and related research
BACKGROUND:Various landmarks can guide tibial component rotational alignment in routine TKA, but with the deeper tibial resection levels common in complex primary and revision TKAs, it is unknown whether these landmarks remain reliable. QUESTIONS/PURPOSES:We asked whether three techniques for determining tibial component rotation based on local anatomic landmarks are reliable deeper tibial resection levels. PATIENTS AND METHODS:The femoral transepicondylar axis was identified by three independent reviewers on MR images of knees from 24 men and 24 women and transposed at a traditional tibial resection level and at the level of the proximal, middle, and distal parts of the proximal tibiofibular joint. Three axes were drawn on axial slices at these levels: the geometric center of the tibial plateau to the medial 1/3 of the tubercle, the posterior condylar line of the tibia, and the largest mediolateral dimension of the tibia. These lines were compared with the transposed femoral epicondylar axis line. RESULTS:The posterior condylar line of the tibia is the least variable local landmark for tibial component positioning at deep resection levels. CONCLUSIONS:Assuming the normal posterior condylar line of the tibia is visible at revision, setting the tibial component at 10° external rotation with respect to the posterior condylar axis of the tibia gets the tibial component within 10° of proper rotation in 86% to 98% of patients, even to the distal part of the proximal tibiofibular joint. The experienced surgeon then can adjust this position based on cues from an assortment of other axes.
10.1007/s11999-010-1330-8
Usefulness of the "grand-piano sign" for determining femoral rotational alignment in total knee arthroplasty.
Ohmori Takaaki,Kabata Tamon,Kajino Yoshitomo,Taga Tadashi,Inoue Daisuke,Yamamoto Takashi,Takagi Tomoharu,Yoshitani Junya,Ueno Takuro,Tsuchiya Hiroyuki
The Knee
BACKGROUND:The "grand-piano sign" is a well-known indicator of proper rotational femoral alignment. We investigated changes in the shape of the femoral anterior cutting plane by changing the rotational alignment, anterior portion depth, and cutting plane flexion angle. METHODS:We simulated various cutting planes after cutting the anterior portion of the femur next to the distal femoral osteotomy in 50 patients with varus knee and also a femoral anterior osteotomy with four degree (S group) and seven degree (T group) flexion angles regarding the mechanical axis. We defined the final cutting plane as the farthest position that we could reach without making a notch and the precutting plane as two millimeters anterior from the final cutting plane. The simulated resection plane was rotated to produce external and internal rotation angles of 0°, three degrees, and five degrees relative to the surgical transepicondylar axis (SEA). We investigated medial and lateral portions of the femoral anterior cutting plane length ratio (M/L). RESULTS:When we cut parallel to SEA, M/L was 0.67±0.09 and 0.62±0.12 in the T and S groups, respectively. M/L was approximately 0.8 and 0.5 with five degree internal and external rotations, respectively (P<0.01). On comparing final cutting and precutting planes, there were no significant differences in M/L without five degree external rotation in the T group and no significant difference in any case in the S group (P>0.01). CONCLUSIONS:The ideal M/L of the femoral anterior cutting plane was 0.62-0.67. M/L did not change with a precutting plane in almost all rotational patterns.
10.1016/j.knee.2017.11.008
Femoral component placement changes soft tissue balance in posterior-stabilized total knee arthroplasty.
Muratsu Hirotsugu,Matsumoto Tomoyuki,Kubo Seiji,Maruo Akihiro,Miya Hidetoshi,Kurosaka Masahiro,Kuroda Ryosuke
Clinical biomechanics (Bristol, Avon)
BACKGROUND:We developed a new tensor for total knee arthroplasty enabling the soft tissue balance measurement after femoral trial placement with the patello-femoral joint reduced. The purpose of the present study is to compare the measurements of joint gap and ligament balance between osteotomized femoral and tibial surfaces in posterior-stabilized total knee arthroplasty with that between surfaces of femoral trial component and tibial osteotomy. METHODS:Using this tensor, the effect of femoral trial placement on the soft tissue balance was analyzed in 80 posterior-stabilized total knee arthroplasties for varus osteoarthritic knees. Both joint gap and varus ligament imbalance were measured with 40 lb of joint distraction force at extension and flexion, and compared between before and after femoral trial placement. FINDINGS:In assessing the joint gap, there was significant decrease as much as 5.3mm at extension, not flexion, after femoral trial prosthesis placement. Varus ligament imbalances were significantly reduced with 3.1° at extension and increased with 1.2° in average at flexion after femoral trial placement. INTERPRETATION:These changes at extension were caused by tensed posterior structures of the knee with the posterior condyle of the externally rotated aligned femoral trial. At the knee flexion, medial tension in the extensor mechanisms might be increased after femoral trial placement with patello-femoral joint repaired, and increased varus imbalance. Accordingly, we conclude that intensive medial release before femoral component placement to obtain rectangular joint gap depending on the conventional osteotomy gap measurement has a possible risk of medial looseness after total knee arthroplasty.
10.1016/j.clinbiomech.2010.06.020
Intraoperative Tibial Anteroposterior Axis Could Not Be Replicated After Tibial Osteotomy in Total Knee Arthroplasty.
Kawaguchi Kohei,Inui Hiroshi,Taketomi Shuji,Yamagami Ryota,Nakazato Keiu,Tanaka Sakae
The Journal of arthroplasty
BACKGROUND:We evaluated the effect of the anteroposterior (AP) axis of the proximal tibia defined at the cutting surface using an image-free navigation system in total knee arthroplasty. METHODS:This prospective study included 68 patients (79 knees) who underwent total knee arthroplasty. The tibial AP axis was registered in the navigation system with reference to Akagi's line, connecting the middle of the posterior cruciate ligament to the medial border of the patellar tendon attachment at the tibial joint surface. After proximal tibial osteotomy, the AP axis was replicated as the AP(O) axis. We measured the difference between the AP axis defined at the joint surface and the AP(O) axis defined at the osteotomy surface. RESULTS:The AP(O) axis at the osteotomy surface internally rotated 2.0° to the AP axis at the joint surface, and the AP(O) axis outlier (difference to AP axis: >3°) occurred in 54% (43 knees). In the >3° malrotation group, internal malrotation occurred in 37% (30 knees) and external malrotation occurred in 17% (13 knees). In the outlier analysis, the left knees were significantly found in the internal outlier group. CONCLUSION:The tibial AP axis, connecting the middle of the posterior cruciate ligament to the medial border of the patellar tendon attachment defined at the tibial joint surface, could not be replicated at the tibial osteotomy surface. If the tibial components were set depending only on the AP axis defined at the osteotomy surface, the tibial components could internally rotate and have more outliers, especially in the left knees.
10.1016/j.arth.2019.05.058
The effect of the posterior slope of the tibial plateau osteotomy with a rotational error on tibial component malalignment in total knee replacement.
Tsukeoka T,Tsuneizumi Y,Lee T H
The bone & joint journal
We performed a CT-based computer simulation study to determine how the relationship between any inbuilt posterior slope in the proximal tibial osteotomy and cutting jig rotational orientation errors affect tibial component alignment in total knee replacement. Four different posterior slopes (3°, 5°, 7° and 10°), each with a rotational error of 5°, 10°, 15°, 20°, 25° or 30°, were simulated. Tibial cutting block malalignment of 20° of external rotation can produce varus malalignment of 2.4° and 3.5° with a 7° and a 10° sloped cutting jig, respectively. Care must be taken in orientating the cutting jig in the sagittal plane when making a posterior sloped proximal tibial osteotomy in total knee replacement.
10.1302/0301-620X.95B9.31775
Large osteophyte removal from the posterior femoral condyle significantly improves extension at the time of surgery in a total knee arthroplasty.
Journal of orthopaedics
Removing osteophytes from the posterior compartment of the femur eliminates the tenting effects on the joint capsule and consequently increases the extension gap in total knee arthroplasty. However, there is no clear association with the size of osteophytes removed and the potential degree of additional extension achieved at time of surgery. AIMS:Correlate the size of posterior osteophytes removed with the degree of extension gained intraoperatively in total knee arthroplasty and develop a radiological classification system to grade these osteophytes. METHODS:Patients who underwent a TKA had pre and post operative sagittal radiographs assessed and classified according to 4 different categories of a proposed classification system. Knee extension was then assessed by a computer navigated system before incision and after implant insertion. Confounding factors were controlled and considered on the analysis. The study was done retrospectively. RESULTS:147 patients were included in the study. Ninety-three (63.2%) patients had osteophytes on the posterior aspect of the femur completely removed and fifty-four patients (36.8%) did not have radiological evidence of osteophytes on the posterior aspect of the femur. There was a positive and linear correlation (Pearson correlation 0.327, p .005) between osteophyte size and degree of extension corrected at time of surgery. On Multivariate Logistic Regression Analysis, we found that small osteophytes (Grade 1) did not seem to affect the extension, while removing Grade 2 or Grade 3 osteophytes lead to a gain in extension of 2.7 and 4.5° respectively. CONCLUSION:Removing large osteophytes (Grade 2 and Grade 3) from the posterior femoral compartment can be used as an adjuvant strategy to ensure that intraoperative extension is optimal. However removing small osteophytes (Grade 1) should not be expected to affect extension at the time of surgery in TKA and could increase intra-operative time and morbidity.
10.1016/j.jor.2019.10.021
Intraoperative changes in medial joint gap after posterior femoral condylar resection, posterior osteophyte removal, and femoral component placement during primary total knee arthroplasty.
The Knee
BACKGROUND:"Mid-flexion stability" is important for superior patient satisfaction following total knee arthroplasty (TKA). Thus, it is important to control medial joint gap intraoperatively as a countermeasure. However, reports on the precise intraoperative changes in medial joint gap during TKA are scarce. This study evaluated the intraoperative changes in medial joint gap during TKA. METHODS:We studied 167 knees with varus osteoarthritis that underwent 80 cruciate-retaining (CR) and 87 posterior-stabilized (PS) TKAs between January 2018 and December 2020. We measured the intraoperative changes in medial joint gap with a tensor device at 137.5 N. RESULTS:The medial joint gap after posterior femoral condylar resection was significantly increased not only at 90° of flexion but also at 0° of extension in CR and PS TKAs (p < 0.01). The medial joint gap after posterior osteophyte removal was significantly increased not only at 0° of extension but also at 90° of flexion in CR and PS TKAs (p < 0.01). The medial joint gap at 0° of extension was reduced by 0.60 mm after femoral component placement in PS TKA. CONCLUSION:Surgeons need to pay close attention to these intraoperative changes in medial joint gap by measuring the medial joint gap before and after each procedure or assuming the changes in those values before bone cutting to achieve superior patient satisfaction following TKA.
10.1016/j.knee.2022.08.008