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Joanne B Adams - One of the best experts on this subject based on the ideXlab platform.

  • total knee arthroplasty in patients with greater than 20 degrees flexion contracture
    Clinical Orthopaedics and Related Research, 2006
    Co-Authors: Keith R Berend, Adolph V Lombardi, Joanne B Adams
    Abstract:

    Fixed flexion contracture can present a technical challenge in total knee arthroplasty. Various techniques of addressing these deformities have been described including additional bony resection, ligamentous releases, and the use of increasing constraint. We retrospectively reviewed the clinical outcomes of 40 patients (52 knees) with fixed flexion contracture greater than or equal to 20 degrees treated with revision TKA and a stepwise algorithmic approach to treating the contracture. A cruciate-retaining Device was used in 31 knees, a posterior stabilized design was used in 14, a posterior stabilized Constrained Device was used in five knees, and a rotating hinged design in was used in two knees. Full correction was achieved intraoperatively. Ninety-four percent of knees had less than 10 degrees residual contracture at an average followup of 37 months. We revised one case of postoperative instability in the posterior stabilized group and we had one infection in the cruciate-retaining group. No other revisions were performed. The stepwise algorithmic approach to treating fixed flexion deformity presented in this study in primary total knee arthroplasty is safe and effective.

  • a Constrained Device with increased range of motion prevents early dislocation
    Clinical Orthopaedics and Related Research, 2006
    Co-Authors: Keith R Berend, Adolph V Lombardi, Michael Welch, Joanne B Adams
    Abstract:

    Constrained components can treat or prevent instability after total hip arthroplasty. Some previous designs have shown a high rate of early dislocation. These early dislocations appear to be secondary to component impingement and levering out of the femoral head. We report the early rate of dislocation in 81 consecutive patients undergoing Constrained total hip arthroplasty using a novel Constrained Device that allows substantially more range of motion and a higher lever out strength. One hip redislocated at 6 months followup, for a success rate of 98.8%. The success rate was 93% for patients for whom a Constrained Device was placed during revision for recurrent instability. This Device allows a higher range of motion before prosthetic impingement and maintains a higher levering out strength when impingement occurs. These changes should provide long lasting hip stability in these difficult cases. Level of Evidence: Therapeutic study, level IV (case series). See Guidelines for Authors for a complete description of levels of evidence.

Keith R Berend - One of the best experts on this subject based on the ideXlab platform.

  • total knee arthroplasty in patients with greater than 20 degrees flexion contracture
    Clinical Orthopaedics and Related Research, 2006
    Co-Authors: Keith R Berend, Adolph V Lombardi, Joanne B Adams
    Abstract:

    Fixed flexion contracture can present a technical challenge in total knee arthroplasty. Various techniques of addressing these deformities have been described including additional bony resection, ligamentous releases, and the use of increasing constraint. We retrospectively reviewed the clinical outcomes of 40 patients (52 knees) with fixed flexion contracture greater than or equal to 20 degrees treated with revision TKA and a stepwise algorithmic approach to treating the contracture. A cruciate-retaining Device was used in 31 knees, a posterior stabilized design was used in 14, a posterior stabilized Constrained Device was used in five knees, and a rotating hinged design in was used in two knees. Full correction was achieved intraoperatively. Ninety-four percent of knees had less than 10 degrees residual contracture at an average followup of 37 months. We revised one case of postoperative instability in the posterior stabilized group and we had one infection in the cruciate-retaining group. No other revisions were performed. The stepwise algorithmic approach to treating fixed flexion deformity presented in this study in primary total knee arthroplasty is safe and effective.

  • a Constrained Device with increased range of motion prevents early dislocation
    Clinical Orthopaedics and Related Research, 2006
    Co-Authors: Keith R Berend, Adolph V Lombardi, Michael Welch, Joanne B Adams
    Abstract:

    Constrained components can treat or prevent instability after total hip arthroplasty. Some previous designs have shown a high rate of early dislocation. These early dislocations appear to be secondary to component impingement and levering out of the femoral head. We report the early rate of dislocation in 81 consecutive patients undergoing Constrained total hip arthroplasty using a novel Constrained Device that allows substantially more range of motion and a higher lever out strength. One hip redislocated at 6 months followup, for a success rate of 98.8%. The success rate was 93% for patients for whom a Constrained Device was placed during revision for recurrent instability. This Device allows a higher range of motion before prosthetic impingement and maintains a higher levering out strength when impingement occurs. These changes should provide long lasting hip stability in these difficult cases. Level of Evidence: Therapeutic study, level IV (case series). See Guidelines for Authors for a complete description of levels of evidence.

Adolph V Lombardi - One of the best experts on this subject based on the ideXlab platform.

  • total knee arthroplasty in patients with greater than 20 degrees flexion contracture
    Clinical Orthopaedics and Related Research, 2006
    Co-Authors: Keith R Berend, Adolph V Lombardi, Joanne B Adams
    Abstract:

    Fixed flexion contracture can present a technical challenge in total knee arthroplasty. Various techniques of addressing these deformities have been described including additional bony resection, ligamentous releases, and the use of increasing constraint. We retrospectively reviewed the clinical outcomes of 40 patients (52 knees) with fixed flexion contracture greater than or equal to 20 degrees treated with revision TKA and a stepwise algorithmic approach to treating the contracture. A cruciate-retaining Device was used in 31 knees, a posterior stabilized design was used in 14, a posterior stabilized Constrained Device was used in five knees, and a rotating hinged design in was used in two knees. Full correction was achieved intraoperatively. Ninety-four percent of knees had less than 10 degrees residual contracture at an average followup of 37 months. We revised one case of postoperative instability in the posterior stabilized group and we had one infection in the cruciate-retaining group. No other revisions were performed. The stepwise algorithmic approach to treating fixed flexion deformity presented in this study in primary total knee arthroplasty is safe and effective.

  • a Constrained Device with increased range of motion prevents early dislocation
    Clinical Orthopaedics and Related Research, 2006
    Co-Authors: Keith R Berend, Adolph V Lombardi, Michael Welch, Joanne B Adams
    Abstract:

    Constrained components can treat or prevent instability after total hip arthroplasty. Some previous designs have shown a high rate of early dislocation. These early dislocations appear to be secondary to component impingement and levering out of the femoral head. We report the early rate of dislocation in 81 consecutive patients undergoing Constrained total hip arthroplasty using a novel Constrained Device that allows substantially more range of motion and a higher lever out strength. One hip redislocated at 6 months followup, for a success rate of 98.8%. The success rate was 93% for patients for whom a Constrained Device was placed during revision for recurrent instability. This Device allows a higher range of motion before prosthetic impingement and maintains a higher levering out strength when impingement occurs. These changes should provide long lasting hip stability in these difficult cases. Level of Evidence: Therapeutic study, level IV (case series). See Guidelines for Authors for a complete description of levels of evidence.

Peter Rindal - One of the best experts on this subject based on the ideXlab platform.

  • fast private set intersection from homomorphic encryption
    Computer and Communications Security, 2017
    Co-Authors: Hao Chen, Kim Laine, Peter Rindal
    Abstract:

    Private Set Intersection (PSI) is a cryptographic technique that allows two parties to compute the intersection of their sets without revealing anything except the intersection. We use fully homomorphic encryption to construct a fast PSI protocol with a small communication overhead that works particularly well when one of the two sets is much smaller than the other, and is secure against semi-honest adversaries. The most computationally efficient PSI protocols have been constructed using tools such as hash functions and oblivious transfer, but a potential limitation with these approaches is the communication complexity, which scales linearly with the size of the larger set. This is of particular concern when performing PSI between a Constrained Device (cellphone) holding a small set, and a large service provider (e.g. WhatsApp), such as in the Private Contact Discovery application. Our protocol has communication complexity linear in the size of the smaller set, and logarithmic in the larger set. More precisely, if the set sizes are Ny

  • fast private set intersection from homomorphic encryption
    IACR Cryptology ePrint Archive, 2017
    Co-Authors: Hao Chen, Kim Laine, Peter Rindal
    Abstract:

    Private Set Intersection (PSI) is a cryptographic technique that allows two parties to compute the intersection of their sets without revealing anything except the intersection. We use fully homomorphic encryption to construct a fast PSI protocol with a small communication overhead that works particularly well when one of the two sets is much smaller than the other, and is secure against semi-honest adversaries.The most computationally efficient PSI protocols have been constructed using tools such as hash functions and oblivious transfer, but a potential limitation with these approaches is the communication complexity, which scales linearly with the size of the larger set. This is of particular concern when performing PSI between a Constrained Device (cellphone) holding a small set, and a large service provider (e.g. WhatsApp), such as in the Private Contact Discovery application.Our protocol has communication complexity linear in the size of the smaller set, and logarithmic in the larger set. More precisely, if the set sizes are Ny < Nx, we achieve a communication overhead of O(Ny log Nx). Our running-time-optimized benchmarks show that it takes 36 seconds of online-computation, 71 seconds of non-interactive (receiver-independent) pre-processing, and only 12.5MB of round trip communication to intersect five thousand 32-bit strings with 16 million 32-bit strings. Compared to prior works, this is roughly a 38--115x reduction in communication with minimal difference in computational overhead.

Mäkelä, Keijo T. - One of the best experts on this subject based on the ideXlab platform.

  • Implant survival of Constrained acetabular Device in primary total hip arthroplasty based on data from the Finnish Arthroplasty Register
    'Elsevier BV', 2020
    Co-Authors: Karvonen Mikko, Laaksonen Inari, Pulkkinen Pekka, Eskelinen Antti, Haapakoski Jaason, Puhto Ari-pekka, Kettunen Jukka, Manninen Mikko, Mäkelä, Keijo T.
    Abstract:

    Background: Constrained acetabular Devices were developed to prevent dislocations after total hip arthroplasty (THA). However, the data on their success have been contradictory. In this study, we aimed to assess implant survival of the Constrained acetabular Device in primary THA based on the Finnish Arthroplasty Register data. Methods: A total of 373 primary THAs with Constrained acetabular Devices inserted from 2006 to 2017 were included. A reference group was formed on a 1:3 basis and matched for age, sex, and diagnosis, consisting of 1118 conventional THAs. Implant survival estimates using death as a competing risk were assessed with revision for any reason and for any aseptic reason as the endpoints. The Cox multiple regression models were adjusted for age, sex, and diagnosis. The mean follow-up time was 3.3 (0-12.4) years for the Constrained Device group and 3.8 (0-12.0) years for the reference group. Results: Overall, there were 21 revisions in the Constrained Device group and 49 in the reference group. The 8-year survivorship for any reason was 94% (confidence interval [CI]: 91-96) for the Constrained Device group and 93% (CI: 89-97) for the reference group. With revision for any aseptic reason as the endpoint, the 8-year survivorships were 97% (CI: 95-99) and 94% (CI: 90-98), respectively. During the first 1.5 years, the Constrained acetabular Device group had a similar revision risk (hazard ratio: 1.09 [CI: 0.57-2.07], P = .8) to that of the reference group. Conclusion: The Constrained acetabular Device had good survival in primary THA, and our results support its continued use even in high-risk patients. (C) 2019 The Authors. Published by Elsevier Inc.Peer reviewedNon Peer reviewe