Scaphoid fracture is most common in young individuals of working age. Without adequate diagnosis and treatment, long-term results are poor. Operative treatment is being recommended increasingly often instead of a long time in cast, although there is no evidence-based support for its superiority. The present thesis focuses on diagnostic problems and therapeutic consequences of acute scaphoid fractures and of scaphoid reconstruction when other treatments have failed. Simultaneous plain radiographs and computed tomography were done in 97 injured wrists. Structural assessments of plain radiography images were highly predictive with respect to the risk of having a displaced or comminute fracture as diagnosed on computed tomography. Any finding of a gap or step-off > 0.5 mm, the presence of an intermediate fragment or a dorsal lunate tilt of ≥ 15° identified 81 % of fractures that were displaced or comminuted when investigated with computed tomography. Eighty-three patients were randomly allocated to and received either nonoperative treatment in cast or operative treatment with the aim of assessing long-term outcome of the two treatment options. Fifty-two of the patients were occupationally active. From an occupational perspective with an early return to work, surgical treatment was superior in individuals with manual employment, and from a health economic perspective conservative treatment was superior in non-manual workers. Patients treated for scaphoid fractures generally do well up to 13 years after the injury based on limb-specific outcome scores. No benefits were identified with operative treatment compared to non-operative treatment in cast. On the contrary, there was an increased risk for osteoarthritis in the scaphotrapezial joint in those who were operated. The patient-rated long-term results of silicone implant arthroplasty were good, with pain relief and reasonable hand function in many patients up to 20 years after surgery.

Adverse effects of cyclooxygenase (COX) inhibitors on bone healing have previously been demonstrated in diaphyseal fracture models in animals. In spite of that, they are widely used as postoperative analgesics in orthopaedic surgery. After joint replacement, a bone repair process starts at the interface between bone and cement. If this process is disturbed, the prosthesis may never become rigidly fixed to the bone, leading to migration and with time loosening. This thesis investigates the effects of a selective COX-2 inhibitor (parecoxib or celecoxib) on bone healing in metaphyseal bone in a rat model and on knee prosthesis migration after total knee replacement, as measured with radiostereometric analysis. Blood loss, postoperative recovery, and the 2-year subjective outcome, were also measured. In addition, a hemoglobin dilution method for blood loss estimation, used in this thesis, was evaluated. In the first study, pull-out force of a screw inserted in metaphyseal bone of the tibia in rats was only marginally decreased by parecoxib after 7 days but not after 14 days. In the second and third study, celecoxib treatment resulted in less pain postoperatively in conjunction with total knee replacement (TKR), but no effects were seen on blood loss, range of motion, subjective outcome, or prosthesis migration after 2 years. Comparing the true blood loss of blood donors with the blood loss estimated by the hemoglobin dilution method, this method was found to underestimate the true blood loss. It is therefore not suitable for calculation of the absolute blood loss volume, but may be used for a rough estimate. In summary, celecoxib and presumably other cyclooxygenase inhibitors seems not likely to increase the risk of prosthesis loosening.

Eight out of ten people in the United States will have problems with low back pain at some point in their life. The most significant surgical treatments for low back pain can be distributed into two main groups of solutions: arthrodesis and arthroplasty. Spinal arthrodesis consists of the fusion of a degenerated functional spine unit (FSU) to alleviate pain and prevent mechanical instability. Spinal arthroplasty consists of the implantation of an artificial disc to restore the functionality of the degenerated FSU. The objective of this study is to analyze and compare the alteration of the biomechanics of the lumbar spine treated either by arthrodesis or arthroplasty. A three-dimensional finite element model of a ligamentous lumbar motion segment, constituted of two FSUs, was built and simulated through a static analysis with the finite element software ABAQUS. It was shown that the mobility of the segment treated by arthrodesis was reduced in all rotational degrees of freedom by an average of approximately 44%, relative to the healthy model. Conversely, the mobility of the segment treated by arthroplasty was increased in all rotational degrees of freedom by an average of approximately 52%. The FSU implanted with the artificial disc showed a high risk of instability and further degeneration. The mobility and the stresses in the healthy FSU, adjacent to the restored FSU in the segment treated by arthroplasty, were also increased. In conclusion, the simulation of the arthroplasty model showed more risks of instability and further degeneration, on the treated level as well as on the adjacent levels, than in the arthrodesis model.

Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 162-175). Also available on the Internet.

Femoral neck fracture (FNF) is a great challenge for today´s health care and is associated with high mortality and morbidity in the elderly.  In the short term several studies in the literature have demonstrated improved hip function, quality of life and fewer re-operations in elderly patients treated with total hip arthroplasty (THA) instead of internal fixation (IF). There are few reports on the long-term outcome comparing IF and THA. The vast majority of orthopaedic departments in Sweden use the direct lateral (DL) or posteriolateral (PL) approaches for hip arthroplasty. The PL approach has been linked to an increased risk of dislocation of the prosthesis and a higher rate of revision surgery in comparison to the DL approach. There are few reports focusing on radiological risk factors for prosthetic dislocation and patient reported hip function comparing the two surgical approaches for hip arthroplasty in FNF. The randomized controlled trial (RCT) is the gold standard for evaluating medical or surgical interventions. An RCT of high quality has to be internally and externally valid. Internal validity refers to a correct study design to avoid bias skewing the results. External validity (EV) refers to whether the results will be clinically relevant to a definable group of patients and can be extrapolated to the general health care situation. There are only a few reports in the orthopaedic literature focusing on the EV of published studies and none in the field of hip fractures. Study I: This is a RCT of 100 patients with a displaced FNF comparing THA and IF. Follow-up evaluations were performed at three months and 1, 2, 4, 11 and 17 years. It was found that the Harris hip score (HHS) was higher and the rate of reoperations lower for patients treated with THA. Study II: This is a prospective cohort study of 185 hips, comparing the DL and the PL approaches in patients treated with a hemiarthroplasty (HA) for a displaced FNF. Follow-up was after 1 year. There was no difference in patient reported outcome between the groups measured with the HHS and WOMAC index. The PL approach resulted in a higher re-operation rate while the DL approach in a higher incidence of limping. Study III: This is a retrospective cohort study of 373 patients with a cemented bipolar HA using a PL approach for a FNF with a follow-up ranging from 6 months to 7 years. Radiographs and all surgical records were reviewed regarding femoral offset (FO), leg length discrepancy (LLD) and Wiberg angle. Patients with recurrent dislocations had a decreased postoperative FO, LLD and shallower acetabulum on the operated side compared with their controls. Study IV: This is a prospective cohort study of 840 hips comparing patients included in a RCT with those that did not give their informed consent (NC) or did not fulfill the criteria for participating in the trial (MS). Patients in the NC and MS groups had an increased mortality rate in comparison to those included in the study. We did not find any differences in hip function between these groups. The main conclusions of this thesis are: Healthy and lucid elderly patients with good hip function preoperatively, should be treated with THA for a displaced FNF. The DL approach is favourable in treating displaced FNF with HA due to its decreased risk of reoperation but with an identical hip function outcome as the PL approach. Care should be taken to restore the LLD and FO otherwise this may increase the risk of recurrent dislocation of a HA. Our findings suggest that trial participants had a lower mortality rate than non-participants but the functional outcome of non-participants appeared to be satisfactory. This is important to take into consideration when extrapolating study results to a health care system. / Lårbenshalsfrakturer (FNF) är en utmaning för dagens sjukvård och förknippad med hög mortalitet i den äldre befolkningen. FNF orsakas främst av lågenergitrauma efter fall i samma plan hos patienter med benskörhet. Total höftledsprotes (THA) har visat sig ge en bättre höftfunktion, livskvalitet med färre omoperationer hos äldre patienter än sluten reposition samt fixering med skruvar (IF) under de första två-fyra åren efter operation. Få studier har publicerats med långtidsuppföljning av THA jämfört med IF. Vid behandling av felställd FNF med halv höftledsplastik (HA) eller THA finns olika kirurgiska metoder (snittföring) för implantation av protesen. Majoriteten av ortopedkliniker i Sverige använder direkt lateral (DL) eller posteriolateral (PL) snittföring. PL har kopplats till en ökad risk för luxation av protesen (urledsvridning), vilket i sin tur genererat en högre risk för omoperation jämfört med DL. Få studier har utvärderat höftfunktion med avseende på snittföring. Detsamma gäller vilka radiologiska faktorer som påverkar risken förprotesluxation. Det finns olika typer av studiedesigner för utvärdering av medicinska och kirurgiska behandlingsmetoder. Studiedesignen med högst bevisvärde anses vara den randomiserade kontrollerade studien (RCT). För att en RCT skall hålla hög kvalitet krävs intern och extern validitet. Intern validitet syftar på ett korrekt studieupplägg som mäter det som avses och undviker påverkan av icke önskvärda faktorer. Extern validitet (EV) innebär att erhållna resultat från studien är generaliserbara och kan extrapoleras till andra grupper än den studerade. Det inga rapporter i ortopediska litteraturen med fokus på EV med patienter som drabbats av FNF. Studie I: Prospektiv randomiserad studie av 100 patienter med en felställd FNF jämförs THA med IF med avseende på höftfunktion och reoperationer. Uppföljning gjordes efter tre månader samt 1, 2, 4, 11 och 17 år. HHS som mått på höftfunktion var högre och andelen reoperationer lägre för patienter som behandlades med THA. Studie II: Prospektiv kohortstudie med 183 patienter med felställd FNF behandlade med HA och antingen DL eller PL. Vi fann ingen skillnad i patientrapporterad höftfunktion utvärderat med HHS och WOMAC efter 1 år men en ökad förekomst av hälta vid DL. Studie III: Retrospektiv kohortstudie av 373 patienter opererade med en cementerad bipolär HA och PL. Postoperativa röntgenbilder granskades avseende femoral offset (FO), postoperativ benlägdsskillnad (LLD) samt acetabulär Wibergvinkel och relaterades till återkommande protesluxationer. Detta relaterades till återkommande luxationer. Uppföljningstiden varierade mellan 6 månader och 7 år. Patienter med återkommande luxationer hade en minskad postoperativ global FO, förkortad LLD och grundare acetabulum på den opererade sidan jämfört med kontroller. Studie IV: Prospektiv kohortstudie av 840 patienter med felställd FNF där patienter som ingick i en RCT jämförs med de som inte gav sitt samtycke för deltagande eller ej inkluderats i screeningprocessen. De patienterna som inte gav sitt samtycke hade ökad dödlighet, men ingen skillnad i höftfunktion jämfört med deltagare. Slutsatser • Friska och kognitivt vitala äldre patienter med god höftfunktion innan en felställd lårbenshalsfraktur bör behandlas med total höftledsprotes. • DLsnittföring ger ett lika bra patientrapporterad höftfunktion men en ökad förekomst av hälta jämfört med PL snitt vid behandling med halvprotes på grund av en felställd lårbenshalsfraktur. • Ansträngning bör göras för att återställa benlängdsskillnad samtfemoral offset och därigenom minska risken för återkommande luxation. • Våra resultat tyder på att patienter som deltar i en randomiserad studie har lägre dödlighet än patienter som avböjt att delta samt de som missats i screeningprocessen. Det är viktigt att ta hänsyn till när extrapolerar studieresultat till ett hälso-och sjukvårdssystem. Detta bör vägas in i värderingen av studieresultatens externa validitet.

Λόγω των θεωρητικών πλεονεκτημάτων τους, τα συστήματα ισχίου που συνδυάζουν μεταβλητούς αυχένες και μεγάλες κεφαλές απέκτησαν βαθμιαία μεγάλη δημοτικότητα. Όμως, μεταξύ των άλλων, ανησυχίες διατυπώθηκαν για τις αλλαγές που τα συστήματα αυτά επιφέρουν στο πρότυπο των φορτίσεων στο εγγύς μηριαίο. Πράγματι, πρόσφατες αναλύσεις φορτίσεων έδειξαν ότι η χρήση των συναρμολογούμενων αυχένων και των μεγάλων κεφαλών αλλάζει σημαντικά την κατανομή των φορτίων κατά μήκος του μηριαίου. Η αρχική μας υπόθεση είναι ότι οι μεταβολές αυτές επηρεάζουν την πρώιμη άπω μετανάστευση του μηριαίου στυλεού. Εξετάσαμε, κατόπιν, την επίδραση της διαμέτρου της κεφαλής και της γεωμετρίας του αυχένα στην μετανάστευση του στυλεού μετά δύο χρόνια παρακολούθησης σε μια σειρά 116 ασθενών (125 ισχίων), οι οποίοι υποβλήθηκαν σε πρωτογενή ΜοΜ ΟΑΙ με την εγγύς αρθρωτή πρόθεση Profemur®E (Wright Medical Technology Inc., Arlington, TN) συνδυασμένη με κεφαλές μεγάλης διαμέτρου (≥40mm). Βρήκαμε ότι η επιλογή της γεωμετρίας του αυχένα και της διαμέτρου της κεφαλής δεν είχε καμία επίδραση στην μετανάστευση του στυλεού. Μία πολυπαραγοντική ανάλυση παλινδρόμησης που περιέλαβε τους συγχυτικούς παράγοντες του δείκτη μάζας σώματος, της ποιότητας του οστού, της πλήρωσης του αυλού σε διάφορες θέσεις και της θέσης τοποθέτησης του στυλεού απεκάλυψε μόνο μια αρνητική συσχέτιση μεταξύ της καθίζησης και της πλήρωσης του αυλού στο ύψος της μέσης του στυλεού. Η στατιστική ανάλυση δεν επιβεβαίωσε την αρχική μας υπόθεση ότι η επιλογή της γεωμετρίας του αυχένα και/ή της διαμέτρου της κεφαλής επηρεάζει την πρώιμη άπω μετανάστευση του στυλεού. Απεδείχθη όμως η σημασία της σωστής εκτίμησης του μεγέθους του στυλεού. Για να διερευνήσουμε παραπέρα αν τα διαφορετικά πρότυπα φορτίσεων των διαφόρων κατευθύνσεων του αυχένα και των διαφορετικών διαμέτρων της κεφαλής παίζουν κάποιο ρόλο στην αυξημένη συχνότητα χαλάρωσης, σχεδιάσαμε μια ανάλυση πεπερασμένων στοιχείων και χρησιμοποιήσαμε σαν πρότυπο το σύστημα με τον ευθύ αυχένα και την κεφαλή των 28 χιλ. Χρησιμοποιώντας στοιχεία που προήλθαν από αξονικές τομογραφίες, αλλά και τη χρήση μιας σταθερής μετρητικής μηχανής, ένα πτωματικό μηριαίο και ο αρθρωτός στυλεός Profemur®E ψηφιοποιήθηκαν πλήρως, οδηγώντας μέσω του λογισμικού ANSYS Workbench σε ένα τρισδιάστατο μοντέλο πεπερασμένων στοιχείων. Αρχικά, προσδιορίσθηκαν τα φορτία και οι παραμορφώσεις, εστιάζοντας σε ορισμένες περιοχές κατά μήκος του μηριαίου: στο μηριαίο πλήκτρο και στην εξωτερική επιφάνεια κάτω από τον μείζονα τροχαντήρα, στην περιοχή του άκρου του στυλεού, καθώς και κατά μήκος της τραχείας γραμμής. Η ανάλυση των πεπερασμένων στοιχείων απέδειξε ότι η χρήση των μεγάλων κεφαλών προκαλεί σημαντικές αλλαγές στις παραμορφώσεις μέσα στον οστικό όγκο, σε σχέση με το μοντέλο με την κεφαλή των 28 χιλ. Στην εξωτερική επιφάνεια του μηριαίου, κατά μήκος της τραχείας γραμμής και στο άκρο του στυλεού η αύξηση της διαμέτρου οδηγεί σε αύξηση των παραμορφώσεων, ενώ στην περιοχή του μηριαίου πλήκτρου συμβαίνει το αντίθετο. Κατόπιν υπολογίσθηκαν οι μέσες τιμές των παραμορφώσεων για καθεμία από τις 11 γεωμετρίες του αυχένα, εστιάζοντας σε συγκεκριμένες περιοχές ενδιαφέροντος: στην έσω πλευρά του μηριαίου στο μηριαίο πλήκτρο, στην έξω πλευρά στην περιοχή κάτω από τον μείζονα τροχαντήρα, καθώς επίσης στην πρόσθια και οπίσθια επιφάνεια του μηριαίου και σε μια κυκλική περιοχή γύρω από το άκρο του στυλεού. Συγκρινόμενοι με το σύστημα με τον ευθύ αυχένα, ο αυχένας με πρόσθια κλίση 15° έδειξε μια αύξηση 17% και 17.7% στην πρόσθια και οπίσθια επιφάνεια του μηριαίου καιφαίνεται να είναι ο πιο επικίνδυνος. Ο ίδιος αυχένας έδειξε τη μεγαλύτερη αύξηση των παραμορφώσεων στην εξωτερική περιοχή ενδιαφέροντος (13%) και στο μηριαίο πλήκτρο (5%). Στην περιοχή του άκρου του στυλεού η μεγαλύτερη αύξηση καταγράφηκε με τον διπλής γωνίας βλαισό-οπίσθιας κλίσης αυχένα (15.4%), ενώ με τον 15° πρόσθιας κλίσης ήταν 11%. Πιστεύουμε, πάντως, ότι η δημοσιευμένη μεγαλύτερη συχνότητα άσηπτης χαλάρωσης των συγκεκριμένων συστημάτων δεν μπορεί να εξηγηθεί με τα ευρήματα αυτής της μελέτης. Αντίθετα η εξήγηση πρέπει να αναζητηθεί στη βιοδραστικότητα των μεταλλικών ιόντων που παράγονται από τις ΜοΜ συνδέσεις και όχι μόνο στην εμβιομηχανική αυτών των συστημάτων. / Due to their theoretical advantages, hip systems combining modular necks and large diameter femoral heads have gained gradually popularity. However, among others, concerns regarding changes in the load transfer patterns were raised. Recent stress analyses have indeed shown that the use of modular necks and big femoral heads alters significantly the strain distribution along the femur. Our original hypothesis was that these changes may affect early distal migration of a modular stem. We examined the effect of head diameter and neck geometry on migration at two years of follow-up in a case series of 116 patients (125 hips), who have undergone primary Metal-on- Metal THA with the modular grit-blasted Profemur®E (Wright Medical Technology Inc., Arlington, TN) stem combined with large-diameter heads (≥40mm). We found that choice of neck geometry and head diameter has no effect on stem migration. A multivariate regression analysis including the confounding variables of the body mass index, bone quality, canal fill and stem positioning revealed only a negative correlation between subsidence and canal fill in midstem area. Statistical analysis didn’t confirm our hypothesis that choice of neck geometry and/or head diameter affects early distal migration of a modular stem. However, the importance of correct stem sizing was revealed. In order to further investigate whether the different strain distributions of the various neck geometries and head diameters play a role in the increased rate of loosening, we designed a Finite Element Analysis (FEA) and used as reference the loading behavior of the straight-neck system with the 28 mm head. Using data acquired by Computed Tomographies and a Coordinate Measurement Machine, a cadaveric femur and a Profemur-E modular stem were fully digitized, leading to a three dimensional finite element model in ANSYS Workbench. Firstly, strains and stresses were calculated, focusing on areas of clinical interest: the calcar and below the greater trochanter in the proximal femur, the stem tip region and a profile line along linea aspera. The performed FE analysis revealed that the use of large heads produces significant changes in strain development within the bone volume, with respect to the reference model featuring a typical femoral head of 28mm. In the lateral side, along linea aspera and for the stem tip area increasing the head diameter, results in strain rise, while in the calcar area the opposite is observed. Mean strain values, for each of the 11 available neck geometries were then calculated, focusing on specific regions of interest (ROIs) as a whole: medially the calcar and laterally the area below the greater trochanter, as well as, the anterior and the posterior surfaces of the femur and a circumferential area around the stem tip. Compared with the straight neck system, the 15° anteverted neck system showed an increase of 17% and 17.7% in the mean strain developed at the anterior and posterior ROIs respectively and seems to be the most precarious. The same neck showed the greatest strain increase also at the lateral ROI (13%) and at the calcar (5%). At the stem tip the greatest increase was recorded with the double-angled valgus-retroverted neck (15.4%), while for the 15° anteverted neck was 11%. We believe, however, that the reported higher incidence of aseptic loosening of modular-neck stems cannot be confirmed only by the findings of this study. Instead, the explanation should be sought also in the bioreactivity of the metal ions generated by the metal-on-metal junctions and not in the biomechanics of these systems alone.

No description available.

Purpose: To determine whether reduced serum levels of AHSG and elevated levels of BMP-2, 4, 7 are associated with post-arthroplasty HO. Patients: Thirty arthroplasty patients were included, 15 with evidence of peri-articular HO and 15 without (NHO). Methods: Blood samples were collected from all patients ≥ 8 weeks after arthroplasty. Analytes were measured using ELISAs. Mann-Whitney U tests were performed to compare serum analyte concentrations between HO and NHO groups, and between arthroplasty patients and healthy humans. Results: There is no difference in serum concentrations of AHSG, BMP-2, 4, 7 between HO and NHO patients. Arthroplasty patients showed significantly higher BMP-2 and BMP-4 and lower AHSG serum levels compared to healthy humans (p < 0.01). Conclusion: Baseline BMP-2, 4, 7 and AHSG serum levels are not markers of acquired HO. However, elevated baseline levels of BMP- 2, 4 and reduced levels of AHSG appear to be markers of severe inflammatory arthritis.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Purpose: To determine whether reduced serum levels of AHSG and elevated levels of BMP-2, 4, 7 are associated with post-arthroplasty HO. Patients: Thirty arthroplasty patients were included, 15 with evidence of peri-articular HO and 15 without (NHO). Methods: Blood samples were collected from all patients ≥ 8 weeks after arthroplasty. Analytes were measured using ELISAs. Mann-Whitney U tests were performed to compare serum analyte concentrations between HO and NHO groups, and between arthroplasty patients and healthy humans. Results: There is no difference in serum concentrations of AHSG, BMP-2, 4, 7 between HO and NHO patients. Arthroplasty patients showed significantly higher BMP-2 and BMP-4 and lower AHSG serum levels compared to healthy humans (p < 0.01). Conclusion: Baseline BMP-2, 4, 7 and AHSG serum levels are not markers of acquired HO. However, elevated baseline levels of BMP- 2, 4 and reduced levels of AHSG appear to be markers of severe inflammatory arthritis.