Does The Anterior Cruciate Ligament-deficient And The Patellofemoral Degeneration Influence The Outcome Of Fixed-bearing Unicondylar Knee Arthroplasty

Objective: To investigate the influences of the ACL’s defects and the patellofemoral degeneration to UKA,to clear up whether the ACL’S defects and the patellofemoral degeneration are contraindications of UKA.Methods: First: in this study,we collected all the cases of unicondylar knee arthroplasty(UKA)from January 2011 to June 2014 in our hospital and had a follow-up more than 1 year.Then,we divided all the cases into two groups by the standard of the preoperative MRI or the deficient ACL in UKA,one with intact ACL and the other with deficient ACL.Data were collected with all patients assessed post-operatively using the Oxford knee score(OKS),the Western Ontario and Mc Master Universities Osteoarthritis Index(WOMAC)and American Knee Society score(AKSS).In the end,we clarified whether the scores from different groups are different.Meanwhile,we find out whether the rates and reasons of UKA revision from the two groups are different;Second: we collected all the cases of unicondylar knee arthroplasty(UKA)from January 2011 to April 2015 in our hospital and had a follow-up about 2 years.Then,we divided all the cases into two groups by the standard of the preoperative Anterior knee pain、Ahlback grading system and Altman scoring system respectively,one is the experiment group and the other is the control group.Data were collected with all patients assessed post-operatively using the Oxford knee score(OKS),the Western Ontario and Mc Master Universities Osteoarthritis Index(WOMAC)and American Knee Society score(AKSS).In the end,we clarified whether the scores from different groups are different,we find out whether the rates and reasons of UKA revision from the two groups are different.Results: First: The clinical outcome of the group with deficient ACL(OKS t=22.63±8.19、change in OKS t=17.47±7.82、AKS knee t=91.16±10.28、AKS function t=87.28±7.61、WOMAC t=8.59±2.94)was not statistically different with the control group(OKS t=22.82±10.57、change in OKS t=16.73±9.32、AKS knee t=91.66±11.71、AKS function t=88.55±10.57、WOMAC t=8.52±3.77).The revision rate of the group with deficient ACL was 6.25%,the other groups’ revision rate was 6.63%.Chi-square test was used to compare the two revision rates and p value was greater than 0.05,there was no statistically significant difference between the two groups.The reasons for UKAs’ revision were similar between the two groups;Second: The clinical outcome of the anterior knee pain group(OKS t=21.88±7.09、change in OKS t=16.60±8.32、AKS knee t=92.12±9.47 、 AKS function t=87.52±6.35 、 WOMAC t=8.59±3.04)was not statistically different with the control group.Regarding the medial degeneration of the patellofemoral joint by the Ahlback and the Altman,the clinical outcome is as following: OKS(t=22.70±7.35、t=21.38±7.41)、change in OKS(t=18.27±9.18、t=17.77±9.26)、AKS knee(t=97.14±8.44、t=93.29±8.52)、AKS function(t=84.09±15.31、t=89.38±14.30)、WOMAC(t=9.09±1.09、t=8.51±1.29).The statistically difference is absent.Patients with lateral patellar degeneration had the more inferior outcome than those with normal joints.The clinical scores are OKS(t=26.45±8.24 、 t=26.31±9.35)、 change in OKS(t=14.27±3.62、t=13.59±8.06)、AKS knee(t=89.27±11.22、t=90.41±9.38)、AKS function(t=80.64±10.28、t=84.47±13.60)、WOMAC(t=8.81±2.15、t=8.94±1.51).Despite the lower clinical outcome scores,the patients with lateral degeneration had excellent clinical outcome.The revision rate of the group with patellofemoral degeneration was8.0%,the other groups’ revision rate was 6.8% by Ahlback grading system.;The revision rate of the group with patellofemoral degeneration was7.2%,the other groups’ revision rate was 6.5% by Altman scoring system.Chi-square test was used to compare the two revision rates and p value was greater than 0.05,there was no statistically significant difference between the two groups.The reasons for UKAs’ revision were similar between the two groups.Conclusion: First: to the cases with deficient ACL,if there is no preoperative instability,the clinical outcome was independent of the presence or absence of the deficient ACL.So,the deficient ACL is not the contraindication for the fixed-bearing UKA;Second: The clinical outcome was independent of the presence or absence of pre-operative anterior knee pain.Patients with medial patellofemoral degeneration had a similar outcome to those without.Patients with lateral patellofemoral degeneration had a worse score than those without,but these patients still had a excellent outcome.