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Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_8 | Pages 20 - 20
1 Apr 2017
Meijer M Boerboom A Stevens M Reininga I Janssen D Verdonschot N
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Background

Trabecular metal (TM) cones are designed to fill up major bone defects in total knee arthroplasty. Tibial components can be implanted in combination with a stem, but it is unclear if this is necessary after reconstruction with a TM cone. Implanting a stem may give extra stability, but may also have negative side-effects. Aim of this study was to investigate stability and strain distribution of a tibial plateau reconstruction with a TM cone while the tibal component is implanted with and without a stem, and whether prosthetic stability was influenced by bone mineral density (BMD).

Methods

Tibial revision arthroplasties were performed after reconstruction of an AORI 2B bone defect with TM cones. Plateaus were implanted in seven pairs of cadaveric tibiae; of each pair, one was implanted with and the other without stem. All specimens were loaded to one bodyweight alternating between the medial and lateral tibia plateau. Implant-bone micro motions, bone strains, BMD and correlations were measured and/or calculated.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_8 | Pages 31 - 31
1 Apr 2017
Meijer M Boerboom A Bulstra S Reininga I Stevens M
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Background

Achieving optimal prosthesis alignment during total knee arthroplasty (TKA) is essential. Imageless computer-assisted surgery (CAS) is developed to improve knee prosthesis alignment and with CAS it is possible to perform intraoperative alignment measurements. Lower limb alignment measurements are also performed for preoperative planning and postoperative evaluation. A new stereoradiography system, called EOS, can be used to perform these measurements in 3D and thus measurement errors due to malpositioning can be eliminated. Since both CAS and EOS are based on 3D modeling, measurements should theoretically correlate well. Therefore, objective was to compare intraoperative CAS-TKA measurements with pre- and postoperative EOS 3D measurements.

Methods

In a prospective study 56 CAS-TKAs were performed and alignment measurements were recorded two times: before bone cuts were made and after implantation of the prosthesis. Pre- and postoperative coronal alignment measurements were performed using EOS 3D. CAS measurements were compared with EOS 3D reconstructions. Measured angles were: varus/valgus (VV), mechanical lateral distal-femoral (mLDFA) and medial proximal tibial angle (mMPTA).


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 141 - 141
1 Jul 2014
Meijer M Boerboom A Stevens M Bulstra S Reininga I
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Summary

The EOS stereography system has been developed for the evaluation of prosthetic alignment. This new low-dose device provides reliable 2D/3D measurements of knee prosthesis alignment.

Introduction

Achieving optimal prosthetic alignment during Total Knee Arthroplasty (TKA) is an essential part of the surgical procedure since malpositioning can lead to early loosening of the prosthesis and eventually revision surgery. Conventional weight-bearing radiographs are part of the usual clinical follow-up after both primary TKA and revision TKA (rTKA), to assess alignment in the coronal and sagittal planes. However, proportions and angles may not be correct on radiographs since divergence exists in the vertical and horizontal planes. Furthermore estimating the exact planes by looking at the position of the patella depends on rotation in the hip joint and this may be misinterpreted by the investigator. A computed tomography (CT) scanogram can also be used. However, due to high levels of radiation and costs it is not routinely used. To this end, a new device, the EOS stereography system, has been developed. With this biplanar low-dose X-ray technique, orthogonally made 2D images and 3D reconstructions can be obtained. Advantages of EOS are that images of the leg are obtained on a 1:1 scale with an amount of radiation 800–1000 times lower than CT-scans and 10 times lower than conventional radiographs. Another advantage is that the 3D reconstructions lead to determination of the real coronal and sagittal planes. However, the software for creating 3D reconstructions is developed for the lower limbs without knee prosthesis material. Consequently a reliability study concerning the generation of 2D images and 3D reconstructions of a leg containing a knee prosthesis has not been performed yet. Therefore objective of this study was to investigate interobserver and intraobserver reliability of knee prosthetic alignment measurements after rTKA using EOS.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 55 - 55
1 Jul 2014
Meijer M Boerboom A Stevens M Bulstra S Reininga I
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Summary

Computer assisted surgery (CAS) during total knee arthroplasty (TKA) is known to improve prosthetic alignment in coronal and sagittal plane. In this systematic review, no evidence is found that CAS also improves axial component orientation when used during TKA.

Introduction

Primary total knee arthroplasty (TKA) is a safe and cost-effective treatment for end-stage knee osteoarthritis. Correct prosthesis alignment is essential, since malpositioning of the prosthesis leads to worse functional outcome and increased wear, which compromises survival of the prosthesis. Computer assisted surgery (CAS) has been developed to enhance prosthesis alignment during TKA. CAS significantly improves postoperative coronal and sagittal alignment compared to conventional TKA. However, the influence of CAS on rotational alignment is a matter of debate. Therefore purpose of this review is to assess published evidence on the influence of CAS during TKA on postoperative rotational alignment.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVI | Pages 15 - 15
1 Aug 2012
Allen F Blunn G McCarthy I O'Donnell M Stevens M Goodship A
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Synthetic bone grafts are used in several major dental and orthopaedic procedures. Strontium, in the form of strontium ranelate, has been shown to reduce fracture risk when used to treat osteoporosis. The aim of the study was to compare bone repair in femoral condyle defects filled with either a 10% strontium substituted bioactive glass (StronBoneTM) or a TCP-CaSO4 graft. We hypothesise that strontium substituted bioactive glass increases the rate of bone ingrowth into a bone defect when compared to a TCP-CaSO4 ceramic graft.

A critical size defect was created in the medial femoral condyle of 24 sheep; half were treated with a Sr-bioactive glass (StronBoneTM), and in the other animals defects were filled TCP-CaSO4. Two time points of 90 and 180 days were selected. The samples were examined with regard to: bone mineral density (BMD) from peripheral quantitative CT (pQCT), mechanical properties through indentation testing, and bony ingrowth and graft resorption through histomorphometry.

The radiological density of Sr-bioactive glass in the defect is significantly higher than that of the TCP-CaSO4-filled defect at 90 and 180 days, (p=0.035 and p=0.000). At 90 days, the stiffness of the defect containing Sr-bioactive glass and is higher than that of the TCP-CaSO4 filled defect, (p=0.023). At 6 months there is no significant difference between the two materials. Histomorphometry showed no significant difference in bone ingrowth at any time point, however significantly more of the graft is retained for the StronBoneTM treatment group than the TCP-CaSO4 group at both 0 days (p=0.004) and 180 days (p=0.000). The amount of soft tissue within the defect was significantly less in the StronBoneTM group than for the TCP-CaSO4 group at 90 days (p=0.006) and 180 days (p=0.000)

The data shows the mechanical stability of the defect site is regained at a faster rate with the strontium substituted bioglass than the TCP-CaSO4 alternative. Histomorphmetry shows this is not due to increased bone ingrowth but may be due to the incorporation of stiff graft particles into the trabeculae. Sr-bioactive glass produces a stronger repair of a femoral condyle defect at 3 months compared with TCP-CaSO4.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_IV | Pages 613 - 613
1 Oct 2010
Stevens M Bulstra S Hoekstra T Van Den Akker-Scheek I Wagenmakers R
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Objective of the study is to determine to what extent patients experience more limitations 1–5 years after revision total hip arthroplasty (THA) compared to patients after primary THA, and if this is accompanied by a reduction in physical activity behavior. Five hundred and six patients were included: 372 primary and 134 revision THA. Questionnaires were used to measure limitations and physical activity. Linear regression analysis showed that patients after revision surgery report significantly more, clinically relevant limitations compared with primary THA patients, but did not show a significant difference in mean total minutes of physical activity per week. Physical activity behavior appeared to be similar for primary and revision THA patients. The results stress the importance of determining different aspects of recovery after THA.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_III | Pages 460 - 460
1 Jul 2010
Oberlin O Rey A La T Bisogno G Koscielniak E Stevens M Meyer W Carli M Anderson J
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Objective: To determine patient characteristics and outcomes for extremity rhabdomyosarcoma (RMS) utilizing an international cohort of prospectively treated patients.

Methods: Data were collected from 566 patients (1984 through 2003) treated on cooperative protocols : US IRS III, IV Pilot, IV studies – SIOP 84, 89, 95 studies – Italian ICG 79, 88, 96 studies – German CWS81, 86, 91, 96 studies.

Results: 29 % of the patients were < 3 year old, 36 % were 3 to 10 year old and 35 % > 10 year old. 350 (63%) patients had alveolar RMS and 116 (22%) had regional nodes.

The overall survival and EFS were 65% and 51% at 5 years respectively and 59% and 48% at 10 years respectively.

By univariate analysis, EFS was influenced by age below 3 years but not by age over 10 years (EFS were 61%, 49% and 46% for patients below 3 years, from 3 to 10 and 10 years or more respectively). It was also influenced by tumor invasiveness, tumor size, lymph node involvement, histology, completeness of surgery at diagnosis and cooperative groups. In multivariate analysis of EFS, size, lymph nodes, quality of surgery, cooperative groups had independent impact. Age and histology had no more impact.

OS (univariate analysis) was influenced by age below 3 years but not by age over 10 years (OS were 77%, 61% and 58% for patients below 3 years, from 3 to 10 and 10 years or more respectively). In multivariate analysis, age, lymph nodes, tumour invasiveness, quality of surgery at diagnosis had independent impact. Histology, tumour size and cooperative groups had no more impact.

Conclusion: This analysis shows that significant cut-point for age is 3 years, that histology per se has no impact on OS and EFS. It also underscores the impact of initial surgery on outcome.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 339 - 340
1 May 2010
Van den Akker-Scheek I Stevens M Zijlstra W Groothoff J Bulstra S
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Introduction: Gait before and after total hip arthroplasty (THA) is often determined by walking at preferred speed. However gait function comprises more than just walking at preferred speed. The objective is to describe recovery of gait after THA based on the assessment of spatio-temporal gait parameters determined with an ambulatory system whereby an extended test protocol is used.

Materials and Methods: Sixty-three patients participating in a short-stay program for primary unilateral THA were assessed preoperatively and at 6 weeks and 6 months postoperatively. The spatiotemporal gait parameters walking speed, step length, step duration and variability coefficient (VC) were determined with an ambulatory system using accelerometers. The test protocol contained walking at different speeds, walking while performing an additional cognitive task, and an endurance test.

Results: Patients improved significantly over time; however, the extent and speed of recovery of gait parameters was different for each test part. The relation between walking speed and step length showed systematic improvement when analyzed over a range of speeds. At 6 months, the VC of the additional cognitive task part was comparable with the preferred walking VC. The endurance test results could be predicted from the results of preferred walking.

Conclusion: The assessment of the recovery of gait function requires more than only the assessment of ‘normal’ walking. Particularly, an analysis of walking at different speeds and walking while performing an additional cognitive task demonstrate different aspects of gait recovery after THA.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 339 - 339
1 May 2010
Stevens M Wagenmakers R Van den Akker-Scheek I Groothoff J Zijlstra W Bulstra S
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Introduction: Despite growing awareness of the beneficial effects of physical activity on health, little is known about the amount of physical activity after THA. Although the WOMAC does not give direct information about the amount of physical activity it can be hypothesized that when patients experience limitations this will have an adverse effect on the amount of physical activity they are involved in. In this way the WOMAC can be predictive for the amount of physical activity. The aim of this study is to determine the correlation between the WOMAC and the amount of physical activity and to determine the predictive value of the WOMAC on meeting the (inter-) national guidelines of health -enhancing physical activity.

Materials and Methods: 364 patients with a THA (minimal one year postoperative) were included. Self-reported physical functioning was assessed by means of the WOMAC and the amount of physical activity by means of the SQUASH. Correlations between the WOMAC and SQUASH-scores were assessed using Pearson’s correlation coefficient. Binary logistic regression modelling was used to determine to which extent the score on the WOMAC was predictive in meeting the (inter-)national guidelines.

Results: A significant, low correlation between the WOMAC and SQUASH-scores (range 0.14 – 0.24) was found. Although the WOMAC was a significant predictor to meet the (inter-) national guidelines of physical activity (p< 0.001), the odds-ratio was low (1.022, 95%CI 1.0121.033). The Nagelkerke R2 was 0.069, implicating that 6.9% of the variance could be explained.

Conclusion: The WOMAC is not suitable to predict the amount of physical activity after THA, necessitating the use of additional quantitative outcome measures.