TY - JOUR
T1 - Tibial component overhang following unicompartmental knee replacement
T2 - Does it matter?
AU - Chau, R.
AU - Gulati, A.
AU - Pandit, H.
AU - Beard, D. J.
AU - Price, A. J.
AU - Dodd, C. A.
AU - Gill, H. S.
AU - Murray, D. W.
PY - 2009
Y1 - 2009
N2 - As implants are made in incremental sizes and usually do not fit perfectly, surgeons have to decide if it is preferable to over or undersize the components. This is particularly important for unicompartmental knee replacement (UKR) tibial components, as overhang may cause irritation of soft tissues and pain, whereas underhang may cause loosening. One hundred and sixty Oxford UKRs were categorised according to whether they had minor (or=3 mm, 9%) tibial overhang, or tibial underhang (21%). One year post surgery, there was no significant difference in outcome between the groups. Five years after surgery, those with major overhang had significantly worse Oxford Knee Scores (OKS) (p=0.001) and pain scores (p=0.001) than the others. The difference in scores was substantial (OKS=10 points). There was no difference between the 'minor overhang' and the 'underhang' group. We conclude that surgeons must avoid tibial component overhang of 3 mm or more, as this severely compromises the outcome. Although this study showed no difference between minor overhang or underhang, we would advise against significant underhang because of the theoretical risk of component subsidence and loosening.
AB - As implants are made in incremental sizes and usually do not fit perfectly, surgeons have to decide if it is preferable to over or undersize the components. This is particularly important for unicompartmental knee replacement (UKR) tibial components, as overhang may cause irritation of soft tissues and pain, whereas underhang may cause loosening. One hundred and sixty Oxford UKRs were categorised according to whether they had minor (or=3 mm, 9%) tibial overhang, or tibial underhang (21%). One year post surgery, there was no significant difference in outcome between the groups. Five years after surgery, those with major overhang had significantly worse Oxford Knee Scores (OKS) (p=0.001) and pain scores (p=0.001) than the others. The difference in scores was substantial (OKS=10 points). There was no difference between the 'minor overhang' and the 'underhang' group. We conclude that surgeons must avoid tibial component overhang of 3 mm or more, as this severely compromises the outcome. Although this study showed no difference between minor overhang or underhang, we would advise against significant underhang because of the theoretical risk of component subsidence and loosening.
UR - http://www.scopus.com/inward/record.url?scp=69049119172&partnerID=8YFLogxK
UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19188069
UR - http://dx.doi.org/10.1016/j.knee.2008.12.017
U2 - 10.1016/j.knee.2008.12.017
DO - 10.1016/j.knee.2008.12.017
M3 - Article
VL - 16
SP - 310
EP - 313
JO - The Knee
JF - The Knee
IS - 5
ER -