In vivo flexion and kinematics of the knee after TKA: Comparison of a conventional and a high flexion cruciate-retaining TKA design

Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, GRJ 1215, Boston, MA 02114, USA.
Knee Surgery Sports Traumatology Arthroscopy (Impact Factor: 3.05). 11/2008; 17(2):150-6. DOI: 10.1007/s00167-008-0637-4
Source: PubMed


This study investigated the in vivo 6DOF knee kinematics and tibiofemoral contact location after total knee arthroplasty using a conventional and a high flexion cruciate retaining component (15 NexGen CR, 11 NexGen CR-Flex). Each patient performed a single-leg lunge while being imaged by a dual fluoroscopic imaging system. Data were analyzed at hyperextension, 0 degrees to 90 degrees in 15 degrees intervals, and at maximum flexion. The average maximum weight-bearing flexion for all the CR patients was 110.1 degrees +/- 13.4 degrees , and for all the CR-Flex patients was 108.2 degrees +/- 13.2 degrees . No difference was seen in the maximum flexion achieved by the patients, and the kinematics demonstrated by the groups was similar. However, at high flexion, the tibiofemoral articulating surfaces were more conforming in the CR-Flex design than the CR design, suggesting that the use of the high flexion component improved the tibiofemoral contact environment at high flexion in patients who could achieve high flexion.

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    • "Also, Weeden and Schmidt et al. [20] and Bin and Nam et al. [21] surveyed 50 and 180 TKAs and reported flexion gains of 12° and 6° respectively. However, Suggs and Kwon et al. [22], Kim and Sohn et al. [23], and Seon and Song et al. [24] found no significant difference in clinical outcome between high-flexion and traditional implants. "
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    ABSTRACT: The application of new techniques and materials in total knee arthroplasty (TKA) continue to be a primary focus in orthopedic surgery. The primary aim of the present study is to evaluate post TKA total range of motion (ROM) among a group of patients who received a gender specific high-flexion design modification implant compared to a control group of patients who received non-gender specific implants. The control group was comprised of 39 TKAs that were recruited pre-operatively and received the non-gender specific implant while the study group consisted of 39 TKAs who received gender specific implants. The study group yielded an improvement in mean post-operative ROM of 21° at 12 months, whereas the mean improvement in ROM among the control group was 11°. Thus, the study group had a 10° increased ROM improvement (91%) over the control group (p = 0.00060). In addition, 100% of the subjects with gender specific high-flexion implants achieved greater or equal ROM post-operatively compared to 82% for the control cohort. Lastly, women who exhibited greater pre-operative ROM and lower body mass index (BMI) were found to benefit the most with the gender specific prosthesis. Our study demonstrates that among subjects with a normal BMI, the gender specific high-flexion knee implant is associated with increased ROM as compared to the non-gender specific non-high-flexion implant designs.
    Full-text · Article · Jun 2012 · Journal of Orthopaedic Surgery and Research
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    No preview · Conference Paper · Oct 1988
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    ABSTRACT: Not Available
    No preview · Conference Paper · Oct 1988
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