Bi-cruciate Stabilized Research Articles

Bi-cruciate stabilized total knee arthroplasty restores the native knee alignments better than conventional posterior stabilized total knee arthroplasty.

This study aimed to compare the differences in the radiological, clinical, and functional outcomes and the estimated restoration rate of native knee alignment between total knee arthroplasty (TKA) with bi-cruciate stabilized (BCS) and posterior stabilized (PS) design. This retrospective study included consecutive patients between 2020 and 2021 who underwent TKA. The patients were divided into two groups (group I, Journey II BCS TKA [106 knees]; group II, Persona PS TKA [106 knees]) after 1:1 propensity score matching. We assessed the radiologic parameters in the coronal (constitutional hip-knee-ankle angle [aHKA] and joint line obliquity [JLO]), sagittal, and axial planes. The femoral roll-back, clinical, and functional outcomes were evaluated. The joint perception was evaluated using the forgotten joint score (FJS). Group I had a higher restoration rate of aHKA and JLO postoperatively (P = 0.039 and P < 0.001). The changes in the patella tendon angle, posterior overhang of the femur, patella tilt angle, and patella lateral shift in group II were larger than those in group I (P < 0.001). Group I was superior in the range of motion (ROM) (P = 0.004), femoral roll-back (P < 0.001), and FJS (P = 0.021). BCS TKA demonstrated better restoration of native knee alignments, including constitutional coronal knee alignment and native sagittal knee alignment, and lesser patella lateral shift than conventional PS TKA. In addition, BCS TKA was superior in ROM, femoral roll-back, and joint perception, which were associated with the degree of restoration of constitutional coronal knee alignment. Level III, retrospective cohort study.

Lower Blood Loss with Bicruciate-Retaining Total Knee Arthroplasty Compared with Bicruciate-Stabilized Total Knee Arthroplasty.

Total knee arthroplasty (TKA) is a common surgical procedure to treat end-stage knee osteoarthritis. This study compared blood loss volume and other clinical outcomes between bicruciate-retaining (BCR) and bicruciate-stabilized (BCS) TKA. Ninety-seven participants who underwent unilateral TKA were enrolled. The BCS-TKA and BCR-TKA groups comprised 78 and 19 participants, respectively. Blood loss was calculated using preoperative and postoperative hematocrit values, height, weight, and sex. Measurements were taken immediately after surgery, on days 1 and 7, and total blood loss was calculated up to day 7. Operation time, range of motion at 7 and 14 days postoperatively, blood transfusion requirement, and postoperative complications such as infection, hematoma, and deep vein thrombosis were compared between the groups. Blood loss was comparable between groups at all time points (125.7 vs. 105.4 mL, 57.9 vs. 43.5 mL, and 68.2 vs. 41.7 mL for immediate, day 1, and day 7 postoperatively, respectively; all p > 0.05) except for total blood loss, which was significantly lower in the BCR group compared with the BCS group (190.7 vs. 251.1 mL; p < 0.05). The BCR group also had a longer operation time than the BCS group (131.2 vs. 112.4 minutes; p < 0.05). No other significant differences were observed in other outcomes. Total blood loss up to 7 days postoperatively was significantly lower in the BCR group than in the BCS group despite a longer operation time. This may be attributed to the reduced bone resection and greater soft tissue preservation, including the anterior cruciate and posterior cruciate ligaments, in the BCR technique.

Does Cruciate Ligament Substitution and Implant Asymmetry Make a Difference for Total Knee Arthroplasty Kinematics? A Multi-Implant Evaluation

BackgroundThe non-implanted knee differs in comparison to total knee arthroplasty (TKA) designs, with regard to asymmetry and functionality of the anterior cruciate ligament and the posterior cruciate ligament. While surgeons may choose to implant either posterior stabilized (PS) or bi-cruciate stabilized (BCS) TKAs, substituting for one or both cruciate ligaments, the effects of symmetry versus asymmetry in substituting TKA designs have not been widely analyzed to determine possible benefits. Therefore, the objective of this research study was to determine if either TKA asymmetry and/or anterior ligament stabilization can lead to more normal-like kinematics and clinical benefit for patients. MethodsIn vivo, femoro-tibial kinematics for 64 subjects were evaluated in this retrospective study. Overall, 10 subjects had a normal, nonimplanted knee, 20 had a BCS TKA, and 34 had one of two different PS TKAs. All three TKAs had varying degrees of symmetry incorporated into the design, and all were implanted by the same surgeon and were analyzed using fluoroscopy during a deep knee bend. ResultsAt full extension, the BCS TKA subjects demonstrated a statistically more anterior position of both condyles compared to both PS TKAs. The BCS TKA subjects also experienced more posterior femoral rollback (PFR) and axial rotation in early flexion and from full extension to maximum knee flexion. Additionally, the TKAs in this study having asymmetry experienced greater amounts of PFR and weight-bearing knee flexion. ConclusionsThe results from this study indicated that in early flexion, the anterior cam/post mechanism does pull the femoral component more anterior, and all TKAs experienced PFR when the posterior cam engaged the post. The asymmetric designs also achieved greater rollback and axial rotation compared to the symmetric designs.

Comparison of short-term clinical results between modified kinematically-aligned and guided motion bicruciate stabilized total knee arthroplasty

BackgroundBoth kinematically-aligned (KA) total knee arthroplasty (TKA) and bicruciate stabilized (BCS) TKA aim to reproduce the physiological knee kinematics. In this study, we compared the femoro-tibial component rotational mismatch between patients who underwent modified KA-TKA and those who received guided-motion BCS-TKA, and its influence on the clinical outcomes.MethodsIn this retrospective study, 77 consecutive patients were included and divided into two groups: subjects who underwent modified KA-TKA with Persona (KA Group; n = 42) and those who received BCS-TKA with JOURNEY II (BCS group; n = 35). Range of motion, the 2011 Knee Society Score (KSS), the rotational alignment of the femoral and tibial components, and the correlations between the rotational mismatch and the 2011 KSS subscales were examined.ResultsThe postoperative objective knee indicators (P = 0.0157), patient satisfaction (P = 0.0039) and functional activity scores (P = 0.0013) in the KA group were significantly superior to those in the BCS group 1 year postoperatively. There was no significant difference between the two groups observed in the rotational mismatch. In the BCS group, significant negative correlations were identified between the rotational mismatch and objective indicators, patient satisfaction, and functional activity scores but not in the KA group.ConclusionsThe short-term clinical results following KA-TKA showed superior objective knee indicators, patient satisfaction and functional activity scores. A negative correlation was observed between component rotational mismatch and the 2011 KSS subscales in the BCS group, compared to no relationship found between the two in the KA group. These findings suggested that KA-TKA has a relatively higher tolerance for rotational mismatch than BCS-TKA.

In Vivo Weight-Bearing Kinematics for Constrained Versus Traditional Bicruciate Stabilized Total Knee Arthroplasty Cohorts Compared to the Normal Knee

BackgroundConstrained inserts in total knee arthroplasty (TKA) may offer additional stability, but can this insert type allow unrestricted movements or will the extra conformity cause kinematic conflict with the cam-post mechanism in deeper flexion? The objective of this study was to evaluate the weight-bearing kinematics of both traditional and constrained bicruciate stabilized (BCS) TKA inserts to determine if the rollback induced by the cam-post mechanism will work in unison with the constrained polyethylene insert. MethodsThis study used previously published 3-dimensional model fitting techniques to compare weight-bearing flexion and femoro-tibial condylar motion patterns for 20 patients who had a traditional insert, 20 patients who had a constrained insert, and 10 previously published nonimplanted knees, all performing a deep knee bend activity while under fluoroscopic surveillance. ResultsThe results from this study indicate that subjects having a bicruciate stabilized TKA experienced similar postoperative kinematics for both constrained and unconstrained insert options, comparable to normal knees. ConclusionsSubjects in this study having either a constrained or traditional insert experienced progressive rollback of both condyles, with the lateral condyle rolling more posterior than the medial condyle, leading to axial rotation. Although less in magnitude, these results were comparable to the normal knee in pattern, indicating that kinematic conflict did not occur for subjects having a constrained insert.

The clinical results of bi-cruciate vs posterior stabilized total knee arthroplasty for flexion contracture in osteoarthritic knee.

The improvement of flexion contracture is important in knee arthroplasty since residual flexion contracture postoperatively is associated with decreased quality of life and patient satisfaction. In this study, we investigated the effect of bi-cruciate stabilized (BCS)-type total knee arthroplasty (TKA) as compared to posterior stabilized (PS)-type TKA on osteoarthritic primary knees with flexion contractures. 59 TKAs from January 2014 to December 2020, of which 30 were PS-type TKAs (NexGen LPS-flexⓇ; 76.3years, BMI 27.5) and 29 BCS-type TKAs (Journey IIⓇ; 72.5years, BMI 28.6), were performed for knee osteoarthritis with preoperative flexion contracture of 15° or greater. Full extension was obtained intraoperatively during all TKAs. Clinical outcomes, radiological evaluations, and the amount of additional distal femoral osteotomy during TKA were evaluated in a retrospective study design. The range of motion improved in the both groups. Postoperative flexion contracture was significantly improved in the BCS group. Knee Society Score improved significantly in both groups, with no difference between the two groups. The amount of additional distal femoral osteotomy was 2.5 ± 1.3mm for the PS group, and 1.8 ± 1.5mm for the BCS group, showing a significant difference (p = 0.04). The BCS-type TKA significantly improved preoperative flexion contracture and reduced the amount of additional distal femoral osteotomy compared to PS-type TKA. This is attributed to the anterior cam in the BCS-type TKA, which leads to a smaller amount of protrusion of the posterior femoral condyle from the posterior margin of the tibial component in the BCS-type in knee extension, as compared to the PS-type.

Midterm clinical results of bi-cruciate stabilized total knee arthroplasty compared with posterior stabilized total knee arthroplasty with single radius design

PurposeAttempts have been made to enhance knee prostheses design to improve clinical outcomes including bi-cruciate stabilized (BCS) TKA design and single-radius (SR) femoral component design. The complication rate of first generation BCS (fBCS) TKA was higher than that of standard TKA. Regarding BCS TKA, modification of the fBCS TKA system to the second-generation BCS (sBCS) TKA system was performed to avoid complications. This study aimed to compare the midterm clinical results of sBCS TKA and SR TKA. MethodsWe retrospectively reviewed data from TKA patients. A total of 142 patients who were followed up for at least 5 years were enrolled: 61 TKAs using sBCS and 81 TKAs using the posterior stabilized (PS) single-radius (SR) design. The clinical results at 6 months, 2 years, and 5 years postoperatively were compared between the sBCS and SR PS groups. ResultsAt 6 months postoperatively, the maximum flexion angle (MFA) of the sBCS group was larger than that of the SR PS group. At 2 years, MFA, KOOS subscales of pain and ADL in the sBCS group were better and at 5 years, the MFA, KOOS subscales of pain and QOL in the sBCS group were better than those in the SR group. There was no significant differences of the ratios of complications and revision surgeries between the two groups. ConclusionThe midterm clinical results of sBCS TKA were better than those of SR PS TKA in terms of the MFA and KOOS subscales of pain and QOL.

Correlating Contact Kinematics to Tibial Component Migration Following Cemented Bicruciate Stabilized Total Knee Arthroplasty

BackgroundContact kinematics in total knee arthroplasty (TKA) has been shown to affect tibial component migration. However, previous studies correlating kinematic variables to implant migration were completed with older TKA designs. The goal of this study was to determine if there are associations between contact kinematics and tibial component migration for a cemented, bicruciate stabilized (BCS) TKA system. MethodsA total of 54 knees implanted with a BCS TKA system were analyzed using radiostereometric analysis (RSA). Patients underwent RSA exams at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and 2 years post operation to measure tibial component migration. At 1 year, contact kinematics was evaluated during a quasi-static deep knee bend. Linear regression analyses were performed between kinematic variables and migration values. ResultsSignificant correlations were found between contact kinematics and tibial component migration. Excursion on the lateral condyle was the most consistent variable correlating with implant migration. Six patients had > 0.2 mm migrations from 1 to 2 years post operation indicating continuously migrating tibial components, and most had atypical contact kinematics. ConclusionKinematics was shown to influence tibial component migration. Reduced lateral excursion, suggesting a more constrained lateral condyle, resulted in greater implant migration. The 6 patients who had continuously migrating tibial components had demographic factors that may limit the ability to endure unintended force transmissions caused by abnormal kinematics. These results highlight the importance of restoring knee kinematics with this BCS TKA design to minimize improper force transmissions and resultant increased implant migrations.

Guided-Motion Bicruciate-Stabilized Total Knee Arthroplasty Reproduces Native Medial Collateral Ligament Strain.

Background and Objectives: Guided-motion bicruciate-stabilized (BCS) total knee arthroplasty (TKA) includes a dual cam-post mechanism with an asymmetric bearing geometry that promotes normal knee kinematics and enhances anterior-posterior stability. However, it is unclear whether the improved biomechanics after guided-motion BCS TKA reproduce soft tissue strain similar to the strain generated by native knees. The purpose of this cadaveric study was to compare medial collateral ligament (MCL) strain between native and guided-motion BCS TKA knees using a video extensometer. Materials and Methods: Eight cadaver knees were mounted onto a customized knee squatting simulator to measure MCL strain during flexion in both native and guided-motion BCS TKA knees (Journey II-BCS; Smith & Nephew, Memphis, TN, USA). MCL strain was measured using a video extensometer (Mercury® RT RealTime tracking system, Sobriety s.r.o, Kuřim, Czech Republic). MCL strain level and strain distribution during knee flexion were compared between the native and guided-motion BCS TKA conditions. Results: The mean and peak MCL strain were similar between native and guided-motion BCS TKA knees at all flexion angles (p &gt; 0.1). MCL strain distribution was similar between native and BCS TKA knees at 8 of 9 regions of interest (ROIs), while higher MCL strain was observed after BCS TKA than in the native knee at 1 ROI in the mid portion of the MCL at early flexion angles (p &lt; 0.05 at ≤30° of flexion). Conclusions: Guided-motion BCS TKA restored the amount and distribution of MCL strain to the values observed on native knees.

Do obese patients benefit from a kinematic, appropriately designed total knee prosthesis?

IntroductionModern total knee arthroplasty (TKA) using the Journey 2 implant utilizes a bicruciate stabilized (BCS) technique. However, whether bicruciate stabilized TKA is equally effective across weight classes is unknown. MethodsWe identified patients who underwent primary bicruciate stabilized TKA during 2016 and 2017, at a single institution. All included patients had, at minimum, 2-year follow-up. Patients were categorized into body-mass index (BMI) groups as follows: underweight, normal, or overweight (<30 kg/m2), obese (≥30 to <35 kg/m2), and severely obese (≥35 kg/m2). Patient reported outcome measures (PROMs) were measured at baseline. Both KSS and KOOS JR, along with the Visual Analogue Scale (VAS), were also recorded at follow-up. Pre-operative, post-operative, and pre-to post-operative changes in PROMs were analyzed using analysis of variance (ANOVA) and linear regression. ResultsThe 292 patients had a mean age of 64.8 years and mean BMI of 32.3 kg/m2. There were 116 (39.7%) patients in the underweight, normal, or overweight group, 88 (30.1%) in the obese category, and 88 (30.1%) in the severely obese group. There were no differences between PROMs at baseline or at follow-up (p > 0.10 for all comparisons). There were also no differences in the improvement from pre-to post-operative KSS (p = 0.21) and KOOS JR (p = 0.62). ConclusionsBicruciate stabilized TKA has similar effects on PROMs across BMI groups. These results suggest that bicruciate stabilized TKA is a viable treatment option both for low-weight and high-weight patients.

Rotational mismatch between femoral and tibial components should be avoided in JOURNEY II bi-cruciate stabilized total knee arthroplasty

BackgroundJOURNEY II bi-cruciate stabilized (BCS) knee system, a guided motion total knee arthroplasty (TKA), has been reported to reproduce physiological knee kinematic motion with good clinical outcomes. However, this guided system may be sensitive to the femorotibial rotational alignment. MethodForty-four patients (50 knees) who underwent JOURNEY II BCS TKA were included in this retrospective study. The 2011 Knee Society Score (KSS) and range of motion were assessed pre-operatively and one year postoperatively. The femoral component rotational angle relative to the surgical epicondylar axis and the tibial component rotational angle relative to Akagi’s line were measured postoperatively. The absolute difference between the femoral and tibial component rotational angles was defined as femorotibial component rotational mismatch. The correlation between the parameters of these rotational alignments and postoperative clinical outcomes was evaluated. Additionally, receiver operating characteristic curve analysis was performed to determine the optimal cut-off point of the femorotibial component rotational mismatch. ResultsMean femoral and tibial component rotational angles were 0.4° (internal rotation) and 0.7° (external rotation), respectively. The rotational mismatch of the femorotibial component was 3.2°. There were negative correlations between femorotibial rotational mismatch and clinical outcomes, including objective knee indicators, patient satisfaction, functional activities, and total 2011 KSS. The area under the curve of the femorotibial component rotational mismatch was 0.768 and the cut-off value identified by the Youden index was 2.8°. ConclusionsExcessive rotational mismatch between the femoral and tibial components can negatively influence the clinical outcomes of JOURNEY II BCS TKA.

Both Intraoperative Medial and Lateral Joint Stabilities at Midflexion Influence Postoperative Patient-Reported Outcome Measures Following Bi-Cruciate Stabilized Total Knee Arthroplasty.

Bi-cruciate stabilized (BCS) total knee arthroplasty (TKA) was developed to approximate normal knee kinematics and is expected to improve clinical outcomes. However, the effects of soft tissue balance at the medial or lateral compartment on patient-reported outcome measures (PROMs) following BCS TKA are unclear. The purpose of this study was to clarify the relationship between the medial or lateral component gaps and PROMs following BCS TKA. One hundred seventeen knees with varus deformities which underwent BCS TKA were included in this study. They were divided into two groups according to the validated Japanese version of the Knee Injury and Osteoarthritis Outcome Score for each subscale of pain, symptoms, and activities of daily living (ADL) at 1 year postoperatively: group H consisted of patients with ≥90 points and group L consisted of patients with <90 points. Intraoperative medial and lateral joint laxities at 0°, 30°, 60°, 90°, and 120° flexion measured using a tensor device were compared between the two groups in each subscale. In the pain subscale, the medial joint laxities at 30° (p < 0.05) and 60° flexion (p < 0.05) in group H were significantly smaller than those in group L. In the ADL subscale, the medial joint laxity at 60° flexion in group H was significantly smaller than that in group L (p < 0.05). In the symptom subscale, the lateral joint laxity at 60° flexion in group H was significantly smaller than that in group L (p < 0.05). Surgeons should pay attention to the importance of both medial and lateral joint stabilities to achieve better postoperative PROMs following BCS TKA.

Migration and Inducible Displacement of the Bicruciate-Stabilized Total Knee Arthroplasty: A Randomized Controlled Trial of Gap Balancing and Measured Resection Techniques.

The goal of this study is to investigate the migration and inducible displacement of a bicruciate-stabilized (BCS) total knee arthroplasty implanted using gap balancing (GB) or measured resection (MR) surgical techniques. We hypothesized equal migration and displacement between the techniques. The study is a single-blinded, prospective, randomized controlled trial, with allocation of 71 patients to either GB or MR groups. Fifteen patients were withdrawn, resulting in 31 patients in the GB group and 25 in the MR group. Patients received the JOURNEY II™ BCS implant. Migration and inducible displacement were evaluated using radiostereometric analysis and patient examinations were performed at a 2-week baseline, and at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperation. No differences (P > .05) existed between GB and MR groups for any measurement of tibial or femoral migration. Both groups had tibial migrations below 0.5 mm from baseline to 6 months, and below 0.2 mm from both 6 months to 1 year and 1-2 years postoperation. No differences (P > .05) were found between GB and MR groups for inducible displacement. No differences were found in implant migration or inducible displacement between GB and MR groups. The BCS implant can be expected to have migration risks on par with industry standards and both surgical techniques are safe and effective options for implantation of this implant design.

Comparison of the joint laxity of total knee arthroplasty evaluated by the distraction force and the varus–valgus force

BackgroundComponent gap (CG) measurement help surgeons evaluate intraoperative soft-tissue balance. One technique is measuring the CG using tensioner devices with distraction force. Another is to evaluate the laxity under a varus–valgus force using navigation or robotics. The aim was to compare the JL evaluated by CG and varus–valgus force between the different types of total knee arthroplasties. MethodsForty-three bi-cruciate stabilized (BCS) knees and 33 bi-cruciate retaining (BCR) knees were included. After bone resection and soft tissue balancing, the CG was measured and after the final implantation and capsule closure, JL under a maximum varus–valgus stress was recorded with navigation. JL evaluated by the CG (JLCG) was defined as CG minus selected thickness of the tibial component and JL under varus–valgus force (JLVV) was defined as difference between varus–valgus angles without stress and maximum varus–valgus angles under varus–valgus force. The evaluations were performed at flexions of 10°, 30°, 60° and 90°. ResultsAlthough JLCGs of lateral compartment of BCS were larger than those of BCR, no difference was found between JLVVs of BCS and BCR. Although JLCGs of lateral compartment did not change at each knee flexion angle in both BCS and BCR, JLVVs of lateral compartment increased by 3° from 10° to 90° knee flexion. ConclusionJLVVs of BCS and BCR were equivalent, whereas BCS showed larger JLCGs of lateral compartment. JLVVs of lateral compartment increased by 3° in the range from 10° to 90° knee flexion whereas JLCGs remained stable.

Both intraoperative medial and lateral soft tissue balances influence intraoperative rotational knee kinematics in bi-cruciate stabilized total knee arthroplasty: A retrospective investigation

BackgroundTibial internal rotation following total knee arthroplasty (TKA) is important in achieving favorable postoperative clinical outcomes. Studies have reported the effect of intraoperative soft tissue balance on tibial internal rotation in conventional TKA, no studies have evaluated the effects of soft tissue balance at medial or lateral compartments separately on tibial internal rotation in bi-cruciate stabilized (BCS) TKA. The purpose of this study was to clarify the relationship between medial or lateral component gaps and rotational knee kinematics in BCS TKA.MethodsOne hundred fifty-eight knees that underwent BCS TKA were included in this study. The intraoperative medial and lateral joint laxities which was defined as the value of component gap minus the thickness of the tibial component were firstly divided into two groups, respectively: Group M-stable (medial joint laxity, ≤ 2 mm) or Group M-loose (medial joint laxity, ≥ 3 mm) and Group L-stable (lateral joint laxity, ≤ 3 mm) or Group L-loose (lateral joint laxity, ≥ 4 mm). And finally, the knees enrolled in this study were divided into four groups based on the combination of Group M and Group L: Group A (M-stable and L-stable), Group B (M-stable and L-loose), Group C (M-loose and L-stable), and Group D (M-loose and L-loose). The intraoperative rotational knee kinematics were compared between the four Groups at 0°, 30°, 60°, and 90° flexion, respectively.ResultsThe rotational angular difference between 0° flexion and maximum flexion in Group B at 30° flexion was significantly larger than that in Group A at 30° flexion (*p < 0.05). The rotational angular difference between 30° flexion and maximum flexion in Group B at 30° flexion was significantly larger than that in Group D at 30° flexion (*p < 0.05). The rotational angular differences between 30° or 90° flexion and maximum flexion in Group B at 60° flexion were significantly larger than those in Group A at 60° flexion (*p < 0.05).ConclusionSurgeons should pay attention to the importance of medial joint stability at midflexion and lateral joint laxities at midflexion and 90° flexion on a good tibial internal rotation in BCS TKA.

Evaluation of anteroposterior accelerometric change after bi-cruciate stabilized total knee arthroplasty and posterior stabilized total knee arthroplasty

BackgroundIn conventional total knee arthroplasty (TKA), the anterior cruciate ligament (ACL) is resected. ACL dysfunction causes knee instability and is regarded as one factor in poor TKA outcomes. In bi-cruciate stabilized (BCS) TKA, the implant reproduces ACL function and provides anterior stability. The objective of this study was to evaluate preoperative and postoperative X-rays and accelerometer gait measurements in patients who underwent BCS TKA and posterior-stabilized (PS) TKA to assess the postoperative acceleration changes of knees after these procedures and to compare them in terms of joint range of motion (ROM) and the New Knee Society Score (New KSS). MethodsThe subjects were 60 patients, 30 of whom underwent BCS TKA and 30 PS TKA. Joint ROM, New KSS, lateral X-rays of the standing extended knee, and accelerometer data were evaluated 12 months postoperatively. ResultsThere was no significant difference in joint ROM between the groups. Both had good New KSS results, but the functional activity score was significantly higher after BCS TKA than after PS TKA. X-rays showed a lower posterior offset ratio after BCS TKA than after PS TKA, with anteroposterior positioning closer to that of the normal knee.Accelerometer data showed that postoperative anteroposterior acceleration on the femoral side in the stance phase and swing phase was lower after BCS TKA than after PS TKA. ConclusionCompared with PS TKA, BCS TKA resulted in a higher functional activity score, closer positioning to that of the normal knee on lateral X-ray, and lower anteroposterior acceleration on the femoral side.

Preoperative and intraoperative factors contributing to patient satisfaction after bi-cruciate stabilized total knee arthroplasty.

One of the causes of dissatisfaction following total knee arthroplasty (TKA) is abnormal knee kinematics. A newly designed bi-cruciate stabilized (BCS) TKA system has been developed to produce close-to-normal kinematics because of its anatomic tibiofemoral articular geometry and cam-post mechanism. Although BCS TKA is expected to improve patient satisfaction, no reports have described the appropriate technique or soft tissue handling required to achieve excellent satisfaction with BCS TKA. This study is to identify preoperative and intraoperative predictors of patient satisfaction after BCS TKA. Altogether, we studied 113 knees with primary varus knee osteoarthritis that underwent BCS TKA with a navigation system. Preoperative parameters including Knee Society Score and patient-reported scores [the Knee injury and Osteoarthritis Outcome Score (KOOS)] and intraoperative parameters including coronal, sagittal and axial alignment and joint laxity in each compartment that affected patient satisfaction was evaluated. Satisfaction score was evaluated with use of the 2011 Knee Society Scoring system. The multivariate regression analysis included age and preoperative and intraoperative parameters that correlated with satisfaction scores in the univariate analysis (P < 0.05). The mean satisfaction score was 28.2 ± 6.1. Multivariate regression analysis showed that the predictors of patient satisfaction were a preoperative high KOOS score for activities of daily living (P < 0.001), male sex (P = 0.005), older age (P = 0.027), and minimal medial joint laxity during flexion (P = 0.031). When performing BCS TKA, surgeons should pay attention to maintaining proper stability of the medial compartment, especially during flexion.

Anatomical bi-cruciate retaining TKA improves gait ability earlier than bi-cruciate stabilized TKA based on triaxial accelerometery data: A prospective cohort study

BackgroundTotal knee arthroplasty (TKA) is a common and cost-effective surgical treatment for osteoarthritis of the knee. However, only 82-89% of patients who performed TKA are satisfied with the postoperative outcomes. Therefore, bi-cruciate retaining (BCR) TKA is re-attracting attention. By retaining the anterior cruciate ligament (ACL), the knee may obtain the kinematic pathway that are closer to the native knee. The aim of the present study is to compare the ability to walk before and after surgery in patients who underwent bi-cruciate retaining total knee arthroplasty (BCR TKA) versus bi-cruciate stabilized (BCS) TKA during the early postoperative period. MethodsSubjects included patients who underwent BCR TKA (10 knees) and BCS TKA (15 knees). We administered 10-meter gait tests before surgery and at 6 weeks and 3 months after surgery. We collected the following triaxial accelerometery data with a portable gait analyzer: walking time, number of steps, velocity, stride length, and coefficient of variability (CV) of double-leg support time while walking. ResultsPatients who underwent BCR TKA improved their gait ability [walking time (p < 0.01), number of steps (p < 0.05), velocity (p < 0.01), and stride length (p < 0.01) more than those who received BCS TKA at 6 weeks after surgery. BCR TKA improved gait ability (walking time, number of steps, velocity, and stride length) more than BCS TKA at 6 weeks after surgery. At 6 weeks after surgery, CV of double-leg support time while walking improved more in the BCR TKA group than in the BCS TKA group (p < 0.05). ConclusionsBCR TKA is associated with improved gait ability in the early postoperative period.

Influence of surgical factors on patient satisfaction after bi\u2010cruciate stabilized total knee arthroplasty: retrospective examination using multiple regression analysis

BackgroundOne of the causes of dissatisfaction following total knee arthroplasty (TKA) is abnormal knee kinematics. A newly designed bi-cruciate stabilized (BCS) TKA system has been developed to produce close-to-normal kinematics because of its anatomic tibiofemoral articular geometry and cam-post mechanism. Although BCS TKA is expected to improve patient satisfaction, no reports have described the appropriate technique or soft tissue handling required to achieve excellent satisfaction with BCS TKA. This study is to identify intraoperative surgical predictors of patient satisfaction after BCS TKA.MethodsWe studied 104 knees with primary varus knee osteoarthritis that underwent BCS TKA with a navigation system retrospectively. Surgical parameters including coronal, sagittal and axial alignment and joint laxity in each compartment that affected patient satisfaction was evaluated. Satisfaction score was evaluated with use of the 2011 Knee Society Scoring system. The multivariate regression analysis included age, gender, body mass index and intraoperative parameters that correlated with satisfaction scores in the univariate analysis (P < 0.05). The current study focused on the patient satisfaction score at 1 year postoperatively and didn’t evaluate the long term clinical results nor survivorship.ResultsThe postoperative satisfaction score was 28.6 ± 8.1. Multivariate analysis showed that medial joint laxity at 30° flexion (P = 0.003), tibial excessive external rotation alignment (P = 0,009) and tibial varus alignment (P = 0.029) were predictors of poor satisfaction score.ConclusionsWhen performing BCS TKA, surgeons should pay attention to maintaining proper stability of the medial compartment at mid flexion range and should avoid tibial varus and excessive external rotational alignment.

Posterior tibial slope and anterior post-cam contact can change knee kinematics in extension in bi-cruciate stabilized total knee arthroplasty.

AimsThis study aims to investigate the effects of posterior tibial slope (PTS) on knee kinematics involved in the post-cam mechanism in bi-cruciate stabilized (BCS) total knee arthroplasty (TKA) using computer simulation.MethodsIn total, 11 different PTS (0° to 10°) values were simulated to evaluate the effect of PTS on anterior post-cam contact conditions and knee kinematics in BCS TKA during weight-bearing stair climbing (from 86° to 6° of knee flexion). Knee kinematics were expressed as the lowest points of the medial and lateral femoral condyles on the surface of the tibial insert, and the anteroposterior translation of the femoral component relative to the tibial insert.ResultsAnterior post-cam contact in BCS TKA was observed with the knee near full extension if PTS was 6° or more. BCS TKA showed a bicondylar roll forward movement from 86° to mid-flexion, and two different patterns from mid-flexion to knee extension: screw home movement without anterior post-cam contact and bicondylar roll forward movement after anterior post-cam contact. Knee kinematics in the simulation showed similar trends to the clinical in vivo data and were almost within the range of inter-specimen variability.ConclusionPostoperative knee kinematics in BCS TKA differed according to PTS and anterior post-cam contact; in particular, anterior post-cam contact changed knee kinematics, which may affect the patient’s perception of the knee during activities.Cite this article: Bone Joint Res 2020;9(11):761–767.