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Patients with no functional improvement after total knee arthroplasty show different kinematics.

ABSTRACT: As many as 20 % of all patients following total knee arthroplasty are not satisfied with the result. Rotational alignment is one factor thought to affect clinical outcome. The purpose of this study was to assess relationships between prosthesis rotational alignment, function score and knee kinematics after TKA.In 80 patients a cemented, unconstrained, cruciate-retaining TKA with a rotating platform was implanted. Rotational alignment was measured using CT-scans. Kinematics was assessed using fluoroscopy images.Seventy-three patients were available for follow-up after two years. Nine patients had more than 10° rotational mismatch between the femoral and tibial component in the postoperative CT scans. These patients showed significantly worse results in the function score. While the normal patients with less than 10° rotational mismatch improved from a mean pre-operative 55 points to a mean 71 points at follow-up, the group with more than 10° mismatch deteriorated from a mean 60 points pre-operatively to a mean 57 points at follow-up. The pattern of motion during passive flexion from approximately 0° to 120° was quite different. While external rotation steadily increased with knee flexion in the normal group, there was internal rotation between 30° and 80° of flexion in the group with more than 10° rotational mismatch.Rotational mismatch between femoral and tibial components exceeding 10° resulted in different kinematics after TKA. It might contribute to worse clinical results observed in those patients and should therefore be avoided.

SUBMITTER: Lutzner J

PROVIDER: S-EPMC3427439 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature

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Patients with no functional improvement after total knee arthroplasty show different kinematics.

Lützner Jörg J Kirschner Stephan S Günther Klaus-Peter KP Harman Melinda K MK

International orthopaedics 20120529 9

<h4>Purpose</h4>As many as 20 % of all patients following total knee arthroplasty are not satisfied with the result. Rotational alignment is one factor thought to affect clinical outcome. The purpose of this study was to assess relationships between prosthesis rotational alignment, function score and knee kinematics after TKA.<h4>Methods</h4>In 80 patients a cemented, unconstrained, cruciate-retaining TKA with a rotating platform was implanted. Rotational alignment was measured using CT-scans. K ...[more]

PMID: 22643798

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Project description:PurposeIn total knee arthroplasty (TKA), the posterior tibial slope is not always reconstructed correctly, and the knee ligaments may become too tight in flexion. To release a tight flexion gap, surgeons can increase the posterior tibial slope using two surgical resection techniques: the anterior tibial cortex (ACR) or the centre of tibial plateau (CPR) referencing. It is not known how this choice affects the knee laxity and function during activities of daily living. The aim of this study was to investigate the effect of tibial slope on knee laxity, kinematics and forces during a squatting activity using computer simulation techniques. We hypothesised that the effects depend on the referencing technique utilised.MethodsA validated musculoskeletal model of TKA was used. Knee laxity tests were simulated in flexion and extension. Then, a squat motion was simulated to calculate: movement of the tibiofemoral joint (TFJ) contact points and patello-femoral joint (PFJ) contact force. All analyses were repeated with more anterior (-3°), neutral (0°), and more posterior tibial slope (+3°, +6°, +9°), and with two referencing techniques (ACR, CPR).ResultsKnee laxities increased dramatically with more posterior slope with the ACR technique (up to 400%), both in flexion and in extension. The CPR technique, instead, had much smaller effects (up to 42% variations). During squatting, more slope with the ACR technique resulted in larger movements of the TFJ contact point. The PFJ contact force decreased considerably with more slope with the CPR technique (12% body weight reduction every 3° more posterior slope), thanks to the preservation of the patellar height and quadriceps-femur load sharing.ConclusionACR technique alters considerably the knee laxity, both in flexion and extensions, and surgeons should be cautious about its use. More slope with CPR technique induces more favourable TFJ kinematics and loading of the knee extensor apparatus and does not substantially alter knee laxity. Preferably, the tibial slope resection should be pre-planned thoroughly and performed using CPR technique as accurately as possible. Surgeons can directly translate the results of this study into the clinical practice.

Project description:Arthrofibrosis is characterized by excessive extracellular matrix (ECM) deposition that results in restricted joint motion after total knee arthroplasty (TKA). Current surgical and pharmacologic treatment options are limited. Therefore, an in vitro model for joint myofibroblastogenesis is valuable to investigate the arthrofibrotic process and identify diagnostic biomarkers and treatment options. In this study, we obtained intraoperative posterior capsule (PC), quadriceps tendon (QT), and suprapatellar pouch (SP) tissue from knees of four patients undergoing primary TKA for osteoarthritis and characterized primary outgrowth cells from these tissues in the absence and presence of transforming growth factor beta 1 (TGFβ1), a pro-myofibroblastic cytokine. Light microscopy of knee outgrowth cells revealed spindle-shaped cells while immunofluorescence (IF) established staining for the fibroblast-specific antigen TE-7 and Vimentin, which are characteristics of fibroblasts. These fibroblasts differentiate readily into myofibroblasts as highlighted by enhanced alpha smooth muscle actin (ACTA2) mRNA and protein expression and increased collagen mRNA (i.e., collagen type 1 (COL1A1) and collagen type 3 (COL3A1)) expression and collagenous matrix deposition in the presence of TGFβ1. Of note, these studies also revealed that knee-derived fibroblasts are more sensitive to TGFβ1-mediated myofibroblastogenesis than adipose-derived mesenchymal stem cells. Importantly, while outgrowth fibroblasts isolated from four patients and three anatomical regions exhibit similar gene expression profiles, these knee fibroblasts form a unique gene expression cluster within the fibroblast niche as revealed by RNA-sequencing analysis. In conclusion, our study provides a fibroblast/myofibroblast model of outgrowth knee cells derived from patients undergoing primary TKA that can be employed to assess myofibroblast-related processes and test novel pharmacological strategies in vitro for arthrofibrosis.

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Patients with no functional improvement after total knee arthroplasty show different kinematics.

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Patients with no functional improvement after total knee arthroplasty show different kinematics.

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