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Bircher A.,University of Basel | Friederich N.F.,Kantonsspital Bruderholz | Scherer K.,University of Basel
Contact Dermatitis | Year: 2012

Background. Orthopaedic implants and osteosynthesis materials are increasingly being used. Complications include mainly physical-mechanical problems and infections. Uncommonly, an allergic reaction towards an alloy metal or a bone cement component has been implicated. Potential bone cement allergens include acrylates, benzoyl peroxide, N,N-dimethyl-p-toluidine, and gentamicin. Typical symptoms are pain, swelling, inflammatory skin reactions, implant loosening, and fistula formation. Objectives. To report on 5 patients with complications from a knee or a shoulder joint implant in whom a relevant sensitization to benzoyl peroxide was shown. Methods. Patch tests were performed with the European baseline series, an extended metal series, and a bone cement series. Patch tests with benzoyl peroxide were performed twice in all patients. A bone cement-free replacement was chosen in sensitized patients. Results. In 4 patients sensitized to benzoyl peroxide, a bone cement-free replacement resulted in a considerable decrease or disappearance of pain and swelling, and complete clearing of cutaneous symptoms. Conclusions. Components of bone cement, such as benzoyl peroxide, may rarely cause allergic complications. However, because of the irritant potential of these substances, careful performance, reading and interpretation of the patch tests is required. © 2011 John Wiley & Sons A/S. Source


Hirschmann M.T.,Kantonsspital Bruderholz | Wagner C.R.,OrthoImagingSolutions Ltd. | Rasch H.,Institute for Radiology and Nuclear Medicine | Henckel J.,Imperial College London
BMC Medical Imaging | Year: 2012

Background: SPECT/CT combines high resolution anatomical 3D computerized tomography (CT) and single photon emission computerized tomography (SPECT) as functional imaging, which provides 3D information about biological processes into a single imaging modality. The clinical utility of SPECT/CT imaging has been recognized in a variety of medical fields and most recently in orthopaedics; however, clinical adoption has been limited due to shortcomings of analytical tools available. Specifically, SPECT analyses are mainly qualitative due to variation in overall metabolic uptake among patients. Furthermore, most analyses are done in 2D, although rich 3D data are available. Consequently, it is difficult to quantitatively compare the position, size, and intensity of SPECT uptake regions among patients, and therefore difficult to draw meaningful clinical conclusions.Methods: We propose a method for normalizing orthopaedic SPECT/CT data that enables standardised 3D volumetric quantitative measurements and comparison among patients. Our method is based on 3D localisation using clinically relevant anatomical landmarks and frames of reference, along with intensity value normalisation using clinically relevant reference regions. Using the normalised data, we describe a thresholding technique to distinguish clinically relevant hot spots from background activity.Results: Using an exemplar comparison of two patients, we demonstrate how the normalised, 3D-rendered data can provide a richer source of clinical information and allow quantitative comparison of SPECT/CT measurements across patients. Specifically, we demonstrate how non-normalized SPECT/CT analysis can lead to different clinical conclusions than the normalized SPECT/CT analysis, and that normalized quantitative analysis can be a more accurate indicator of pathology.Conclusions: Conventional orthopaedic frames of reference, 3D volumetric data analysis and thresholding are used to distinguish clinically relevant hot spots from background activity. Our goal is to facilitate a standardised approach to quantitative data collection and comparison of clinical studies using SPECT/CT, enabling more widespread clinical use of this powerful imaging tool. © 2012 Hirschmann et al; licensee BioMed Central Ltd. Source


Hirschmann M.T.,Kantonsspital Bruderholz | Wind B.,Kantonsspital Bruderholz | Amsler F.,Amsler Consulting | Gross T.,University of Basel
Clinical Orthopaedics and Related Research | Year: 2010

Reports using the Constant-Murley score often lack details regarding how strength measurement was performed, which may have an important impact on the results obtained. A description of the measurement is especially important when patients are unable to adopt the prescribed position of 90° shoulder abduction, leading to invalid or highly discrepant scores. We investigated the influence of shoulder abduction and torso position on strength measurement with special emphasis on intraobserver reliability. Thirty-three healthy volunteers were examined using a handheld dynamometer (Isobex®) in 30°, 60°, and 90° abduction with or without stabilization of the torso. A linear correlation between strength measurements in different degrees of abduction was observed, with values at 90° abduction on average 15% lower than at 60° and 45% lower than at 30°. In multivariate analysis, gender and weight had a substantial impact on the strength of individual measurement positions. Intraobserver reliability was related to arm and torso position (intraclass correlation coefficients, 0.71-0.93) and was highest for 90° abduction without torso stabilization. These findings emphasize the importance of standardized torso and arm positions ensuring high reliability when performing the strength measurement of the Constant-Murley score. © 2009 The Association of Bone and Joint Surgeons®. Source


Hirschmann M.T.,Kantonsspital Bruderholz | Fallegger B.,Kantonsspital Bruderholz | Amsler F.,Amsler Consulting | Regazzoni P.,University of Basel | Gross T.,University of Basel
Journal of Orthopaedic Trauma | Year: 2011

OBJECTIVES:: The aim of this study was to investigate the subjective and objective longer-term outcomes after fracture fixation with the Proximal Humerus InterLocking OSteosynthesis (PHILOS) plate. DESIGN:: Minimum 4-year follow-up of a primary prospective cohort study. SETTING:: Single university trauma center. PATIENTS/PARTICIPANTS:: Sixty-four consecutively collected patients fulfilled the study criteria. Seven patients (11%) were lost to follow-up, resulting in 57 patients (65 ± 14 years). INTERVENTION:: Open reduction and internal fixation with the PHILOS® plate. MAIN OUTCOME MEASUREMENTS:: Standardized follow-up including functional outcome instruments (eg, Constant Murley score, Disabilities of the Arm, Shoulder and Hand), rate of complications, and secondary surgeries at 6, 12, and no less than 48 months (uni- and multivariate analysis; P < 0.05). RESULTS:: At the 4- to 6-year follow-up (median 5 years postinjury), patients on average achieved an 87% range of motion of the injured compared with the uninjured shoulder (eg, 133° ± 40° versus 152° ± 26° abduction). Objective and subjective outcome improved significantly during the overall follow-up, most of all in reoperated and younger patients (65 years and younger) and within the first postinjury year. We observed an overall reoperation rate of 29% and 10 patients (17.5%) demonstrated an insufficient result resulting from pain (greater than 3 visual analog scale) or restricted abduction (less than 90°) at longer-term follow-up. First, the need for revision surgery and, second, increasing age were found to be the most predictive factors for unsatisfactory results. CONCLUSIONS:: Fracture fixation with the PHILOS showed good to excellent longer-term results in three fourths of patients with outcome partially still improving after the first postoperative year. Copyright © 2011 by Lippincott Williams & Wilkins. Source


Hirschmann M.T.,Kantonsspital Bruderholz | Keller L.,Kantonsspital Bruderholz | Hirschmann A.,Balgrist | Schenk L.,Kantonsspital Bruderholz | And 5 more authors.
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2013

Purpose: The purpose of the study was to evaluate the clinical and radiological outcomes after medial/lateral collagen meniscus substitution (CMI) at 12 months postoperatively. Methods: Sixty-seven patients (m:f = 47:20, mean age 36 ± 10 years) underwent arthroscopic CMI after previous subtotal medial (n = 55) or lateral meniscectomy (n = 12) due to persistent joint line pain (n = 25) or to prophylactic reasons (n = 42). Clinical follow-up consisted of IKDC score, Tegner score, Lysholm score, and visual analog scale for pain and satisfaction (preinjury, preoperatively, and 12 months postoperatively; follow-up rate 90 %). MRI scans were analyzed according to the Genovese criteria. Results: Nineteen patients (29 %) showed a normal (A), 35 nearly normal (B), 5 abnormal (C), and 1 patient severely abnormal total IKDC score (D). The median Tegner preinjury score was 7 (range 2-10) and at follow-up 6 (range 2-10). The mean Lysholm score before surgery was 68 ± 20 and 93 ± 9 at follow-up. Preoperatively, the mean VAS pain was 4. 4 ± 3. 1 and 2. 0 ± 1. 0 at follow-up. Clinical failure of the CMI occurred in 3 patients (n = 1 infection, n = 1 failure of the implant, n = 1 chronic synovitis). On MRI, the CMI was completely resorbed in 3 patients (5 %), partially resorbed in 55 (92 %), and entirely preserved in 3 (5 %) patients. In 5 patients (8 %) the CMI was isointense, in 54 (90 %) slightly and 1 (2 %) highly hyperintense. 43 (72 %) patients showed an extrusion of the CMI implant of more than 3 mm. Conclusions: Significant pain relief and functional improvement throughout all scores at 1 year was noted. The CMI undergoes significant remodeling, degradation, resorption, and extrusion in most of the patients. No difference in outcomes between the medial and lateral CMI was observed. Level of evidence: Prospective therapeutic study, Level IV. © 2012 Springer-Verlag Berlin Heidelberg. Source

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