The importance of biomechanical restoration for total hip arthroplasty
Kiernan, Sverrir LU
(2020)
In Lund University, Faculty of Medicine Doctoral Dissertation Series
- Abstract
- Total hip arthroplasty (THA) has become a safe and very successful surgical intervention. A vast majority of patients get their expectations met. Improvement of materials, implant designs, and surgical techniques, have extended prosthetic survival. However, inferior placement and sizing of a hip prosthesis are known to increase the risk of mechanical failure, wear, and early loosening as well as patient dissatisfaction. The main objective of this thesis was to evaluate the importance of improved biomechanical restoration for the function and survival of THA, as well as finding ways of achieving this improvement. We used radiostereometry (RSA), low dose computer tomography (CT) for 3D measurements, 3D templating, prosthetic modularity, and... (More)
- Total hip arthroplasty (THA) has become a safe and very successful surgical intervention. A vast majority of patients get their expectations met. Improvement of materials, implant designs, and surgical techniques, have extended prosthetic survival. However, inferior placement and sizing of a hip prosthesis are known to increase the risk of mechanical failure, wear, and early loosening as well as patient dissatisfaction. The main objective of this thesis was to evaluate the importance of improved biomechanical restoration for the function and survival of THA, as well as finding ways of achieving this improvement. We used radiostereometry (RSA), low dose computer tomography (CT) for 3D measurements, 3D templating, prosthetic modularity, and 3D gait analysis, together with patient-reported outcomes.
We found a strong correlation between initial postoperative femoral neck anteversion (FNA) and subsequent posterior rotation and loosening of cemented stems. Our 3D measurement techniques showed near-perfect inter- and intraobserver agreements regarding our femoral offset (FO), acetabular offset (AO), and global offset (GO) measurements. We did not see any differences in RSA migration between uncemented modular and standard stem types, both stabilised well with good migration pattern. Postoperative FNA and FO/AO quota had no impact on uncemented stem migration, maybe due to the study being underpowered. The standard stem tended to result in insufficient GO, whereas the modular stem did not. 3D templating was superior in the correct prediction of the final stem size and neck, but 2D templating overestimated stem-size and underestimated neck-length. There was no statistically significant difference regarding cup size predictions. We found an unexpected progressive varus deformation, with concomitant corrosion-related cobalt ion release, from the modular stem-neck junction. However, the ion-concentrations did not correlate with adverse local tissue reaction (ALTR) as measured with MRI up to 8 years. Biomechanical restoration during THA does positively impact the quality of postoperative overall gait pattern, with faster walking speed and with less trunk lean over the affected side. Increased FNA was associated with increased internal hip rotation during walking. An increase in external hip adduction moments was, on the other hand, not associated with a change in FO/AO quota but with a more upright walking position and increased walking speed.
Biomechanical restoration is important for THA and our studies confirm the need for precise measuring- and evaluation-tools for this kind of research.
(Less) - Abstract (Swedish)
- Höftprotesoperationer har blivit ett säkert och mycket framgångsrikt kirurgiskt ingrepp och lever upp till mycket av de förväntningar som patienterna har. Förbättring av material, protesdesign och kirurgiska tekniker har förlängt protesöverlevnaden påtagligt. Emellertid är icke optimal protesplacering och felaktigt val av komponentstorlekar känt för att öka risken för biomekaniska problem och ökat slitage vilket kan leda till tidig lossning såväl som missnöje hos patienterna. Huvudsyftet med denna avhandling var att utvärdera vikten av förbättrad biomekanisk kirurgisk rekonstruktion avseende funktion och protesöverlevnad, samt att hitta sätt att uppnå denna förbättring. Vi använde radiostereometri (RSA), lågdos datortomografi (CT) för... (More)
- Höftprotesoperationer har blivit ett säkert och mycket framgångsrikt kirurgiskt ingrepp och lever upp till mycket av de förväntningar som patienterna har. Förbättring av material, protesdesign och kirurgiska tekniker har förlängt protesöverlevnaden påtagligt. Emellertid är icke optimal protesplacering och felaktigt val av komponentstorlekar känt för att öka risken för biomekaniska problem och ökat slitage vilket kan leda till tidig lossning såväl som missnöje hos patienterna. Huvudsyftet med denna avhandling var att utvärdera vikten av förbättrad biomekanisk kirurgisk rekonstruktion avseende funktion och protesöverlevnad, samt att hitta sätt att uppnå denna förbättring. Vi använde radiostereometri (RSA), lågdos datortomografi (CT) för 3D-mätningar, 3D-mallningssystem, modularitet av proteskomponenter samt 3D-gånganalys, tillsammans med patientrapporterade resultat.
Vi fann en stark korrelation mellan hur man initialt positionerade en cementerad protesstam i anteversion och hur den senare migrerade med bakre rotation. Våra 3D-mättekniker uppvisade nästan perfekt precision vad gäller våra mätningar av femoral offset (FO), acetabular offset (AO) och global offset (GO). Vi såg inga statistiska skillnader i RSA-migration mellan modulära och standardtyper av ocementerade stammar, båda stabiliserades och uppvisade bra migrationsmönster. Postoperativ anteversion och FO/AO-kvota hade ingen påverkan på stam-migrationen, möjligen kan uteblivna skillnader bero på för få patienter i studien. Standardstammen tenderade att resultera i otillräcklig GO, medan modulära stammen inte gjorde det. 3D-mallning var överlägsen för korrekt förutsägelse av den slutliga stamstorleken och halslängden, men 2D-mallningen överskattade stamstorlek och underskattade halslängd. Det fanns ingen statistisk signifikant skillnad vad gäller förutsägelser om cupstorlek. Vi hittade en oväntad progredierande varusdeformation, med samtidig korrosionsrelaterad koboltjon-frisättning från den modulära stam-hals-kopplingen. Jonkoncentrationerna korrelerade emellertid inte med lokala vävnadsreaktioner (ALTR) mätt med magnetkamera upp till 8 år. Biomekanisk förbättrad rekonstruktion vid höftproteskirurgi påverkar positivt kvaliteten på det totala gångmönstret med snabbare gånghastighet och med mindre bållutning över på den drabbade sidan. Förändring i höftrotation under gång var associerad med förändring i stammens anteversion i samma riktning. En ökning av externa höftadduktionsmoment var däremot inte förknippad med förändring av FO/AO-kvoten utan med en mer upprätt gångposition och ökad gånghastighet.
Biomekanisk rekonstruktion är betydelsefull vid höftproteskirurgi och våra studier konfirmerar behovet av noggranna mät- och utvärderingsverktyg för denna typ av forskning.
(Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/54920261-4583-4aad-b964-643944d45745
- author
- Kiernan, Sverrir
LU
- supervisor
-
- Gunnar Flivik LU
- Martin Sundberg LU
- opponent
-
- Professor Sayed-Noor, Arkan, Umeå University
- organization
- alternative title
- Betydelsen av biomekanisk optimering vid höftproteskirurgi
- publishing date
- 2020
- type
- Thesis
- publication status
- published
- subject
- in
- Lund University, Faculty of Medicine Doctoral Dissertation Series
- issue
- 2020:105
- pages
- 118 pages
- publisher
- Lund University, Faculty of Medicine
- defense location
- Konferenslokalen, Klinikgatan 5, plan 3, Skånes Universitetssjukhus i Lund
- defense date
- 2020-10-09 13:00:00
- ISSN
- 1652-8220
- ISBN
- 978-91-7619-967-1
- language
- English
- LU publication?
- yes
- id
- 54920261-4583-4aad-b964-643944d45745
- date added to LUP
- 2020-09-16 13:45:00
- date last changed
- 2020-09-23 07:54:59
@phdthesis{54920261-4583-4aad-b964-643944d45745,
abstract = {{Total hip arthroplasty (THA) has become a safe and very successful surgical intervention. A vast majority of patients get their expectations met. Improvement of materials, implant designs, and surgical techniques, have extended prosthetic survival. However, inferior placement and sizing of a hip prosthesis are known to increase the risk of mechanical failure, wear, and early loosening as well as patient dissatisfaction. The main objective of this thesis was to evaluate the importance of improved biomechanical restoration for the function and survival of THA, as well as finding ways of achieving this improvement. We used radiostereometry (RSA), low dose computer tomography (CT) for 3D measurements, 3D templating, prosthetic modularity, and 3D gait analysis, together with patient-reported outcomes. <br/><br/>We found a strong correlation between initial postoperative femoral neck anteversion (FNA) and subsequent posterior rotation and loosening of cemented stems. Our 3D measurement techniques showed near-perfect inter- and intraobserver agreements regarding our femoral offset (FO), acetabular offset (AO), and global offset (GO) measurements. We did not see any differences in RSA migration between uncemented modular and standard stem types, both stabilised well with good migration pattern. Postoperative FNA and FO/AO quota had no impact on uncemented stem migration, maybe due to the study being underpowered. The standard stem tended to result in insufficient GO, whereas the modular stem did not. 3D templating was superior in the correct prediction of the final stem size and neck, but 2D templating overestimated stem-size and underestimated neck-length. There was no statistically significant difference regarding cup size predictions. We found an unexpected progressive varus deformation, with concomitant corrosion-related cobalt ion release, from the modular stem-neck junction. However, the ion-concentrations did not correlate with adverse local tissue reaction (ALTR) as measured with MRI up to 8 years. Biomechanical restoration during THA does positively impact the quality of postoperative overall gait pattern, with faster walking speed and with less trunk lean over the affected side. Increased FNA was associated with increased internal hip rotation during walking. An increase in external hip adduction moments was, on the other hand, not associated with a change in FO/AO quota but with a more upright walking position and increased walking speed.<br/><br/>Biomechanical restoration is important for THA and our studies confirm the need for precise measuring- and evaluation-tools for this kind of research.<br/>}},
author = {{Kiernan, Sverrir}},
isbn = {{978-91-7619-967-1}},
issn = {{1652-8220}},
language = {{eng}},
number = {{2020:105}},
publisher = {{Lund University, Faculty of Medicine}},
school = {{Lund University}},
series = {{Lund University, Faculty of Medicine Doctoral Dissertation Series}},
title = {{The importance of biomechanical restoration for total hip arthroplasty}},
url = {{https://lup.lub.lu.se/search/files/83810273/e_nailing_ex_sverrir.pdf}},
year = {{2020}},
}