Sagittal laxity after posterior cruciate ligament-retaining mobile-bearing total knee arthroplasty

Posterior cruciate ligament stretching after posterior cruciate ligament-retaining (CR) total knee arthroplasty (TKA) can lead to an increase in sagittal laxity, knee dysfunction, or accelerated damage to the tibial bearing surface. We conducted a prospective study on 74 consecutive mobile-bearing CR TKA to determine if knee laxity changed with time or if knees with large initial laxity experienced greater increases in laxity. Patients were studied with radiographic posterior and anterior drawer examinations at 3 and 23 months. Model-based shape-matching techniques were used to measure TKA kinematics. We found a 1-mm increase in posterior drawer. Knees with large postoperative drawers did not exhibit increased laxity at last follow-up. The use of a mobile-bearing CR TKA did not significantly modify the midterm knee sagittal laxity.     

In Vivo Kinematic Comparison Between Mobile-Bearing and Fixed-Bearing Total Knee Arthroplasty During Step-Up Activity

Mobile-bearing total knee arthroplasty (TKA) expects high conformity and low contact stress. It is designed to correct the rotational mismatch between femoral and tibial components. We examined the difference in weight-bearing knee kinematics in patients with mobile-bearing and fixed-bearing TKA performing step-up activities. We randomly assigned 40 knees (37 patients) to mobile-bearing TKA (n = 20) or fixed-bearing TKA (n = 20). Using fluoroscopic imaging we evaluated knee kinematics during step-up activity one year after surgery. The total extent of rotation was not different for the two TKAs. Due to the axial rotation of the polyethylene insert, patients with mobile-bearing TKA had a wider range of absolute axial rotation. The position of the medial and the lateral condyles was significantly more posterior in the fixed-bearing TKA. There were only minor kinematic differences between the two TKAs. The polyethylene insert in the mobile-bearing TKA moved as designed especially with respect to the self-alignment feature.     

髌股关节软骨退变程度对单髁置换术后效果的影响

目的探讨髌股关节软骨退变程度对内侧活动平台单髁置换术短期疗效的影响。 方法回顾性分析2017年1月至2018年12月在深圳市人民医院因前内侧骨关节炎行内侧活动平台单髁置换或全膝关节置换术的75例患者资料,依据术中探查髌股关节软骨退变情况分为无退变单髁组(无退变组)、内侧退变单髁组(内侧退变组)、内外退变单髁组(内外退变组)和内外退变全膝组(全膝组)。单因素方差分析对比4组患者术前术后牛津大学膝关节评分(OKS)、美国特种外科医院(HSS)评分、骨关节炎指数(WOMAC)评分,并记录终末随访时有无假体松动、脱位、力线改变等情况。 结果所有患者获得随访,随访时间平均(36±10)个月。4组患者术后OKS评分、HSS评分、WOMAC评分较术前均有改善(F＝18.555,P<0.001;F＝5.867,P＝0.001;F＝22.671,P<0.001);术前术后OKS、HSS、WOMAC评分差值,无退变组与内侧退变组之间差异均无统计学意义(均为P>0.05),内外退变组与无退变组、内侧退变组相比,功能改善程度稍差(均为P<0.05),内外退变组与全膝组之间OKS、HSS、WOMAC评分差值差异无统计学意义(均为P>0.05)。所有病例于末次随访时无假体松动、脱位、力线改变。 结论内侧髌股关节软骨退变对内侧活动平台单髁置换术后疗效影响不大,但面对外侧髌股关节软骨退变时则需慎重,此时选择单髁或是全膝,需个性化考虑。     

Kinematic analysis of kneeling in cruciate‐retaining and posterior‐stabilized total knee arthroplasties

Kneeling is an important function of the knee for many activities of daily living. In this study, we evaluated the in vivo kinematics of kneeling after total knee arthroplasty (TKA) using radiographic based image‐matching techniques. Kneeling from 90 to 120° of knee flexion produced a posterior femoral rollback after both cruciate‐retaining and posterior‐stabilized TKA. It could be assumed that the posterior cruciate ligament and the post‐cam mechanism were functioning. The posterior‐stabilized TKA design had contact regions located far posterior on the tibial insert in comparison to the cruciate‐retaining TKA. Specifically, the lateral femoral condyle in posterior‐stabilized TKA translated to the posterior edge of the tibial surface, although there was no finding of subluxation. After posterior‐stabilized TKA, the contact position of the post‐cam translated to the posterior medial corner of the post with external rotation of the femoral component. Because edge loading can induce accelerated polyethylene wear, the configuration of the post‐cam mechanism should be designed to provide a larger contact area when the femoral component rotates. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:435–442, 2008     

人工全膝关节置换术在外翻膝的临床应用

[目的]探讨人工全膝关节置换术在外翻膝中的手术技术和临床疗效.[方法]2004年3月～2008年9月,对14例16个外翻膝行膝前正中、髌旁内侧入路,常规截骨、外侧软组织松解,后方稳定型假体或后交叉韧带保留型假体的人工全膝关节置换术进行回顾性研究.患者男3例,女11例,平均年龄60.5岁(45～77岁).经过随访比较手术前后膝关节屈伸活动度、KSS评分、膝关节X线情况来评估手术临床效果.[结果]术后平均随访42个月(24～54个月),膝关节屈伸活动度由术前平均82°(伸直0°～屈曲120°)提高到术后120°(伸直0°～屈曲150°);KSS评分:临床评分由术前平均43分(10～65分)提高到术后平均83.9分(70～100分),功能评分由术前平均52.9分(30～70分)提高到术后平均89.3分(75～100分);胫股角由术前平均16.5°(8°～30°)改善纠术后平均7°(5°～10°),膝外翻畸形得到良好的矫正.随访中无深静脉血栓、膝关节感染、髌骨半脱位或脱位并发症发生.[结论]膝前正中、髌旁内侧入路,常规截骨、外侧软组织松解,后方稳定型假体或后交叉韧带保留型假体的TKA治疗外翻膝临床疗效满意.     

The Influence of the Posterior Cruciate Ligament and Component Design on Joint Line Position After Primary Total Knee Arthroplasty

This study investigated the change in joint line position after posterior cruciate–retaining and posterior-stabilized total knee arthroplasty with AMK (DePuy, Warsaw, Ind) and Genesis II (Smith & Nephew, Memphis, Tenn) components. A total of 200 primary total knee arthroplasty patients were randomly selected so as to have 50 patients with each of the 4 prosthesis types. Joint line position was measured on preoperative and 2 year postoperative radiographs by both a lateral and an anteroposterior measurement method. Two-year follow-up functional data were assessed. There were no statistically significant differences in the joint line elevation between posterior-stabilized and posterior cruciate–retaining designs within the same implant system as measured on lateral radiographs. There were no differences in clinical functional outcomes in patients with variable joint line elevation.     

Bi‐Cruciate Retaining Total Knee Arthroplasty Does Not Restore Native Tibiofemoral Articular Contact Kinematics During Gait

Bi‐cruciate retaining (BCR) total knee arthroplasty (TKA) design preserves both anterior and posterior cruciate ligaments with the potential to restore normal posterior femoral rollback and joint kinematics. Abnormal knee kinematics and “paradoxical” anterior femoral translation in conventional TKA designs have been suggested as potential causes of patient dissatisfaction. However, there is a paucity of data on the in vivo kinematics and articular contact behavior of BCR‐TKA. This study aimed to investigate in vivo kinematics, articular contact position, and pivot point location of the BCR‐TKA during gait. In vivo kinematics of 30 patients with unilateral BCR‐TKA during treadmill walking was determined using validated dual fluoroscopic imaging tracking technique. The BCR‐TKA exhibited less extension than the normal healthy knee between heel strike and 48% of gait cycle. Although the average external rotation trend observed for BCR TKA was similar to the normal healthy knee, the range of motion was not fully comparable. The lowest point of the medial condyle showed longer anteroposterior translation excursion than the lateral condyle, leading to a lateral‐pivoting pattern in 60% of BCR TKA patients during stance phase. BCR‐TKA demonstrated no statistical significant differences in anterior–posterior translation as well as varus rotation, when compared to normal healthy knees during the stance phase. However, sagittal plane motion and tibiofemoral articular contact characteristics including pivoting patterns were not fully restored in BCR TKA patients during gait, suggesting that BCR TKA does not restore native tibiofemoral articular contact kinematics. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1929–1937, 2019     

Changes in the rotational axes of the tibiofemoral joint caused by resection of the anterior cruciate ligament

Kinematic alignment is a method of aligning implants in total knee arthroplasty (TKA) that strives to restore the native flexion–extension (F–E) and longitudinal rotation (LR) axes of the tibiofemoral joint. The anterior cruciate ligament (ACL) is typically resected at the time of TKA, which might change the position, and orientation of these axes from that of the native knee. Our objective was to determine whether resecting the ACL causes changes in the F–E and LR axes. A custom designed and validated instrumented spatial linkage (ISL) measured the F–E and LR axes in nine cadaveric knees before and after ACL resection. Changes in these axes were computed for knee flexion from 0° to 120°. For the F–E axis, the two statistically significant yet relatively small changes were internal rotation of 0.5° (p = 0.02) and posterior translation of 0.3 mm (p = 0.04). For the LR axis, the statistically significant and relatively large change was medial translation of 2.1 mm (p = 0.01). Changes to the LR axis in both medial‐lateral position and varus‐valgus orientation varied widely; 77% of a population of knees would have a medial–lateral position change greater than 1 mm, and 53% of a population of knees would have a varus–valgus orientation change greater than 1°. Knowledge of changes of the F–E and LR axes caused by resecting the ACL provides an important baseline for determining the changes in these axes caused by kinematic alignment and mechanical alignment of bi‐cruciate retaining, posterior cruciate retaining, and posterior cruciate substituting implants. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:886–893, 2017.

     

CR假体全膝关节置换术治疗膝骨关节炎的近期疗效

目的探讨保留后交叉韧带假体(CR假体)全膝关节置换术(TKA)治疗膝骨关节炎的近期临床疗效。方法 56例(64膝)膝关节骨关节炎患者采用CR假体进行TKA。比较患者术前、术后1周、术后3个月及术后2年膝关节活动度及膝关节HSS评分。结果 56例TKA患者均恢复满意,且均获得2年以上随访。无一例出现感染、松动及异响。患者术后膝关节疼痛、功能和活动度方面均有明显改善。HSS评分由术前的34~48(41.00±4.34)分提高到术后2年的68~97(86.50±7.57)分,差异有统计学意义(P0.01);其中优46膝,良16膝,可2膝,优良率96.9%。关节活动度由术前的34°~90°(61.93°±18.22°)提高到术后2年的117°~130°(122.17°±3.92°),差异有统计学意义(P0.01)。结论 CR假体TKA对治疗膝骨关节炎近期疗效良好。     

In Vivo Kinematic Analysis of a High-Flexion, Posterior-Stabilized, Mobile-Bearing Knee Prosthesis in Deep Knee Bending Motion

The objective of this study was to evaluate the kinematics of a high-flexion, posterior-stabilized, mobile-bearing total knee arthroplasty (TKA) in weight-bearing, deep knee bending motion. Thirteen patients implanted with the Legacy Posterior Stabilized Flex (Zimmer, Warsaw, IN) mobile-bearing TKA were examined during a deep knee bending motion using fluoroscopy. Femorotibial motion was determined using a 2-dimensional to 3-dimensional registration technique, which used computer-assisted design models to reproduce the position of metallic implants from single-view fluoroscopic images. The average flexion range of motion between the metallic implants was 116°. The average rotation of the femoral component was 9.3° external rotation. The mean kinematic pathway was early rollback, lateral pivot with external rotation, and bicondylar rollback. We found that the kinematic pattern of the Legacy Posterior Stabilized Flex mobile-bearing TKA was different than normal knee kinematics.     

Partial and Combined Partial Knee Arthroplasty: Greater Anterior-Posterior Stability Than Posterior Cruciate–Retaining Total Knee Arthroplasty

BackgroundLittle is known regarding anterior-posterior stability after anterior cruciate ligament–preserving partial (PKA) and combined partial knee arthroplasty (CPKA) compared to standard posterior cruciate–retaining total knee arthroplasty (TKA).MethodsThe anterior-posterior tibial translation of twenty-four cadaveric knees was measured, with optical tracking, while under 90N drawer with the knee flexed 0-90°. Knees were tested before and after PKA, CPKA (medial and lateral bicompartmental and bi-unicondylar), and then posterior cruciate–retaining TKA. The anterior-posterior tibial translations of the arthroplasty states, at each flexion angle, were compared to the native knee and each other with repeated measures analyses of variance and post-hoc t-tests.ResultsUnicompartmental and bicompartmental arthroplasty states had similar laxities to the native knee and to each other, with ≤1-mm differences throughout the flexion range (P ≥ .199). Bi-unicondylar arthroplasty resulted in 6- to 8-mm increase of anterior tibial translation at high flexion angles compared to the native knee (P ≤ .023 at 80-90°). Meanwhile, TKA exhibited increased laxity across all flexion angles, with increased anterior tibial translation of up to 18 ± 6 mm (P < .001) and increased posterior translation of up to 4 ± 2 mm (P < .001).ConclusionsIn a cadaveric study, anterior-posterior tibial translation did not differ from native laxity after PKA and CPKA. Posterior cruciate ligament–preserving TKA demonstrated increased laxity, particularly in anterior tibial translation.     

Adopting the Joint Line Theory for Bone Resection in Cruciate‐Retaining Total Knee Arthroplasty to Prevent Flexion Gap Tightness

BackgroundDuring a conventional measured resection using the posterior reference method for total knee arthroplasty (TKA) in varus knees, proximal tibia is resected from the lateral joint surface for the same thickness as the implant. Distal femur is resected from the worn medial surface for the same thickness as the implant. Posterior femur is resected using the posterior reference method with an external rotation for appropriate degrees. In this situation, although the joint line of the tibia is leveled to the height of lateral joint surface, the posterior joint line of the femur is leveled to the center of medial and lateral posterior condyle, which is a few millimeters lower than the lateral posterior condyle. This discrepancy between the proximal tibia‐posterior femoral joint line causes a tight flexion gap in cruciate‐retaining TKA. Therefore, downsizing of the femur is necessary to adjust the posterior joint line to the level of the lateral condyle.PerspectivesTo avoid this circumstance, the postoperative joint line should be leveled to the center of the original medial and lateral joint surface. Proximal tibia is resected from the lateral joint surface 1 mm to 2 mm thicker than the implant. Distal femur is resected from the worn medial surface 1 mm to 2 mm thinner than the implant. Posterior femur is resected using the posterior reference method with an external rotation for appropriate degrees. In this situation, all the joint lines are leveled to the center of the medial and lateral joint surface. Otherwise, use of an anatomically shaped implant with a physiologic joint line is another option to avoid joint line discrepancy.ConclusionsAdopting joint line theory for bone resection can prevent the flexion gap tightness that likely occurs in cruciate‐retaining TKA.     

Computational analysis of customized cruciate retaining total knee arthroplasty restoration of native knee joint biomechanics

The purpose of this study was to verify if customized prosthesis better preserves the native knee joint kinematics and provides lower contact stress on the polyethylene (PE) insert owing to the wider bone preservation than that of standard off‐the‐shelf prosthesis in posterior cruciate‐retaining type total knee arthroplasty (TKA). Validated finite element (FE) models for were developed to evaluate the knee joint kinematics and contact stress on the PE insert after TKA with customized and standard off‐the‐shelf (OTS) prostheses as well as in normal healthy knee through FE analysis under dynamic loading conditions. The contact stresses on the customized prosthesis decreased by 18% and 8% under gait cycle loading conditions, and 24% and 9% under deep‐knee‐bend loading conditions, in the medial and lateral sides of the PE insert, respectively, compared with the standard OTS prosthesis. The anterior‐posterior translation and internal‐external (IE) rotation in customized TKA were more similar to native knee joint behaviors compared with standard OTS TKA under gait loading conditions. The difference from normal knee kinematics was lower for femoral rollback and IE rotation in customized TKA than in standard OTS TKA in the deep‐knee‐bend condition. In general, customized prostheses achieve kinematics that are close to those of the native healthy knee joint and have better contact stresses than standard OTS prostheses in gait and deep‐knee‐bend loading conditions.     

全膝关节置换术后膝关节线改变与膝前痛的相关性

目的 探讨全膝关节置换术后膝关节线改变与膝前痛的相关性.方法 回顾性分析2008年1月至2010年12月因膝关节骨关节炎行初次全膝关节置换的76例患者的病例资料,男11例,女65例;年龄47～83岁,平均(68.88±7.61)岁.术中应用PFC后稳定型固定平台膝关节假体.术后每12个月定期门诊随访一次.根据Figgie膝关节线测量方法对术前及随访时的关节线进行测量,并计算术前、术后关节线的变化.关节线升高为正值,关节线降低为负值.采用Feller评分法评估术前及随访时的髌骨功能.评估术后24个月的关节线改变水平与Feller髌骨评分的相关性.结果 关节线改变-6.8～10.44 mm,平均(2.69±3.31) mm.随膝关节线升高,Feller髌骨评分呈下降趋势;关节线改变值与Feller髌骨评分呈负相关(r=-0.763,P=0.000).随关节线降低,Feller髌骨评分呈下降趋势;关节线改变值与髌骨评分呈正相关(r=0.914,P=0.000).术后12、24个月关节线改变4 mm以内的患者(55例)Feller髌骨评分均高于关节线改变大于4 mm的患者(21例),差异有统计学意义(t=12.648,P=0.000;t=11.775,P=0.000).结论 对后稳定型固定平台膝关节假体,关节线改变与膝前痛具有相关性,保持关节线变化在±4 mm以内有利于恢复膝关节功能.     

Joint line and patellar height restoration after revision total knee arthroplasty

Background:

Restoration of proper joint line (JL) position and patellar height in revision total knee arthroplasty (TKA) is essential in the recovery of knee function and kinematics. We determined whether the JL position and patellar height could be restored in patients undergoing septic and aseptic revision TKA.

Materials and Methods:

We retrospectively reviewed 70 patients (74 knees) who had revision TKA between September 2004 and December 2010. Forty seven knees had a two stage revision for infected TKA and 27 knees for aseptic failure. The JL position, patellar height and patellar tendon (PT) length were measured and compared between primary TKA and post revision. The clinical scores including a hospital for special surgery (HSS), Knee Society Score (KSS), Western Ontario and McMaster Universities (WOMAC) and range of motion (ROM) were compared.

Results:

The overall JL increased from 17.51 mm to 18.37 mm post revision, the Insall-Salvati (IS) ratio declined from 0.98 to 0.92, and the PT length declined from 42.92 mm to 39.45 mm. 9 of the 21 patellar baja knees improved to normal patellar height. After revision, the JL in the septic group (17.02 mm) was significantly lower than the aseptic group (20.74 mm). The changes of the JL position and IS ratio in the septic group were significantly larger than the aseptic groups (P < 0.05). JL position had a positive correlation to the IS ratio and PT length post revision. The knee function scores including HSS, KSS, WOMAC scores, and ROM all improved post revision compared to pre revision (P < 0.05), and the septic group had a lower knee function compared to the aseptic group. JL position and IS ratio post revision had no correlation to the HSS, KSS, WOMAC scores, and ROM.

Conclusions:

JL position can be sufficiently restored with appropriate distal femoral augment reconstruction after revision TKA, but the patellar height cannot be well improved, especially in the septic revision with obvious PT contracture. No correlation was found between the JL position and patellar height to the knee function post revision TKA.     

Mid-Term Outcomes of Floating Platform Mobile-Bearing Total Knee Arthroplasty Under Navigational Guidance With a Minimum 4-Year Follow-Up

We evaluated 106 knees that underwent primary total knee arthroplasty (TKA) with the navigation-assisted gap balancing technique using an e.-motion cruciate retaining floating platform (FP) mobile-bearing prosthesis to prospectively assess the survival of the e.-motion FP system after a minimum follow-up of 4 years. There was no evidence of any complications, including dissociation or breakage of the polyethylene liner or component loosening at last follow up (5.1 ± 0.6 years). Four knees, however, required re-operation, three for distal femoral fracture, and one for infection. The estimated 5-year prosthesis survival rates without revision for any reason and for prosthesis-associated problems were 96.2% and 100%, respectively. The e.-motion floating platform, with a cruciate retaining design under navigation guidance, demonstrated excellent clinical results and 5-year survival rate.     

Midterm results of cruciate retaining total knee arthroplasty in patellectomized patients

Background:

Total knee arthroplasty (TKA) in patellectomized patients gives inferior results when compared with those in which the patella is present. The literature is ambiguous about the role of cruciate retaining or sacrificing implants for these knees. In this study, we assessed the midterm results of TKA in patellectomized knees using a cruciate retaining implant.

Materials and Methods:

Thirty three patients with a prior patellectomy underwent a cruciate retaining TKA and were followed up for an average of 9.3 years (range 2-14 years). At each followup visit, they were evaluated clinically, radiologically and by the Hospital for Special Surgery Scoring System.

Results:

Twenty one knees did not have any pain or difficulty in climbing stairs, 10 knees were slightly painful on stairs but pain free on walking on flat ground and two knees experienced mild to moderate pain on walking up and down stairs as well as on flat ground. The average range of motion preoperatively was 87°, which postoperatively increased to 118°. The average Hospital for Special Surgery Knee scores increased from 52 to 89 points. None of the knees showed any progressive radiolucencies or evidence of any loosening/osteolysis or fractures in followup.

Conclusion:

Cruciate retaining TKA offers good results at midterm followup in patients with a prior patellectomy.     

Tibiofemoral force following total knee arthroplasty: comparison of four prosthesis designs in vitro.

Despite ongoing evolution in total knee arthroplasty (TKA) prosthesis design, restricted flexion continues to be common postoperatively. Compressive tibiofemoral force during flexion is generated through the interaction between soft tissues and prosthesis geometry. In this study, we compared the compressive tibiofemoral force in vitro of four commonly used prostheses: fixed-bearing PCL (posterior cruciate ligament)-retaining (PFC), mobile-bearing posterior-stabilized (PS), posterior-stabilized with a High Flex femoral component (HF), and mobile-bearing PCL-sacrificing (LCS). Fourteen fresh-frozen cadaver knee joints were tested in a passive motion rig, and tibiofemoral force measured using a modified tibial baseplate instrumented with six load cells. The implants without posterior stabilization displayed an exponential increase in force after 90 degrees of flexion, while PS implants maintained low force throughout the range of motion. The fixed-bearing PFC prosthesis displayed the highest peak force (214 +/- 68 N at 150 degrees flexion). Sacrifice of the PCL decreased the peak force to a level comparable with the LCS implant. The use of a PCL-substituting post and cam system reduced the peak force up to 78%, irrespective of whether it was a high-flex or a standard PS knee. However, other factors such as preoperative range of motion, knee joint kinematics, soft tissue impingement, and implantation technique play a role in postoperative knee function. The present study suggests that a posterior-stabilized TKA design might be advantageous in reducing soft tissue tension in deep flexion. Further research is necessary to fully understand all factors affecting knee flexion after TKA.     

A Validated Forward Solution Dynamics Mathematical Model of the Knee Joint: Can It Be an Effective Alternative for Implant Evaluation?

BackgroundMathematical modeling is among the most common computational tools for assessing total knee arthroplasty (TKA) mechanics of different implant designs and surgical alignments. The main objective of this study is to describe and validate a forward solution mathematical of the knee joint to investigate the effects of TKA design and surgical conditions on TKA outcomes.MethodsA 12-degree of freedom mathematical model of the human knee was developed. This model includes the whole lower extremity of the human body and comprises major muscles and ligaments at the knee joint. The muscle forces are computed using a proportional–integral–derivative controller, and the joint forces are calculated using a contact detection algorithm. The model was validated using telemetric implants and fluoroscopy, and the sensitivity analyses were performed to determine how sensitive the model is to both implant design, which was analyzed by varying medial conformity of the polyethylene, and surgical alignment, which was analyzed by varying the posterior tibial tilt.ResultsThe model predicted the tibiofemoral joint forces with an average accuracy of 0.14× body weight (BW), 0.13× BW, and 0.17× BW root-mean-square errors for lateral, medial, and total tibiofemoral contact forces. With fluoroscopy, the kinematics were validated with an average accuracy of 0.44 mm, 0.62 mm, and 0.77 root-mean-square errors for lateral anteroposterior position, medial anteroposterior position, and axial rotation, respectively. Increasing medial conformity resulted in reducing the paradoxical anterior sliding midflexion. Furthermore, increasing posterior tibial slopes shifted the femoral contact point more posterior on the bearing and reduced the tension in the posterior cruciate ligament.ConclusionA forward solution dynamics model of the knee joint was developed and validated using telemetry devices and fluoroscopy data. The results of this study suggest that a validated mathematical model can be used to predict the effects of component design and surgical conditions on TKA outcomes.