R A van Stralen1, P J C Heesterbeek2, A B Wymenga2. 1. Sint Maartenskliniek, Hengstdal 3, Postbus 9011, 6500 GM, Nijmegen, The Netherlands. R.A.vanStralen@gmail.com. 2. Sint Maartenskliniek, Hengstdal 3, Postbus 9011, 6500 GM, Nijmegen, The Netherlands.
Abstract
PURPOSE: In anteroposterior (AP)-gliding mobile-bearing total knee arthroplasty (TKA), the femoral component can theoretically slide forward resulting in a more anterior contact point, causing pain due to impingement. A lower lever arm of the extensor apparatus can also attribute to higher patella pressures and pain. The goal of this study was to determine the contact point in a cohort of mobile- and fixed-bearing TKAs, to determine whether the contact point lies more anteriorly in mobile-bearing TKA and to confirm whether this results in anterior knee pain. METHODS: We used 38 fixed-bearing TKA and 40 mobile-bearing TKA from a randomized trial with straight lateral knee X-rays and measured the contact point. The functional outcome was measured by Knee Society Score at 12 months postoperatively. Pain scores were analysed using a VAS score (0-100 mm) in all patients at rest and when moving. Difficulty at rising up out of a chair was also assessed using a VAS score. RESULTS: The contact point in mobile-bearing TKA was situated at 59.5 % of the AP distance of the tibia and in the fixed-bearing TKA group at 66.1 % (P< 0.05). Patients with mobile- and fixed-bearing TKAs had similar knee scores, pain scores and difficulty in chair rise. No significant correlation was found between contact point and knee pain. CONCLUSION: The hypothesis of a more anterior contact point in the mobile-bearing cohort was confirmed but no correlation with functional and pain scores in this cohort could be found. The tibiofemoral contact point could not be correlated with a different clinical outcome and higher incidence of anterior knee pain. This study further adds to the knowledge on possible differences between mobile- and fixed-bearing prostheses. Next to that, bad outcomes could not be explained by CP. LEVEL OF EVIDENCE: Case series, Level IV.
PURPOSE: In anteroposterior (AP)-gliding mobile-bearing total knee arthroplasty (TKA), the femoral component can theoretically slide forward resulting in a more anterior contact point, causing pain due to impingement. A lower lever arm of the extensor apparatus can also attribute to higher patella pressures and pain. The goal of this study was to determine the contact point in a cohort of mobile- and fixed-bearing TKAs, to determine whether the contact point lies more anteriorly in mobile-bearing TKA and to confirm whether this results in anterior knee pain. METHODS: We used 38 fixed-bearing TKA and 40 mobile-bearing TKA from a randomized trial with straight lateral knee X-rays and measured the contact point. The functional outcome was measured by Knee Society Score at 12 months postoperatively. Pain scores were analysed using a VAS score (0-100 mm) in all patients at rest and when moving. Difficulty at rising up out of a chair was also assessed using a VAS score. RESULTS: The contact point in mobile-bearing TKA was situated at 59.5 % of the AP distance of the tibia and in the fixed-bearing TKA group at 66.1 % (P< 0.05). Patients with mobile- and fixed-bearing TKAs had similar knee scores, pain scores and difficulty in chair rise. No significant correlation was found between contact point and knee pain. CONCLUSION: The hypothesis of a more anterior contact point in the mobile-bearing cohort was confirmed but no correlation with functional and pain scores in this cohort could be found. The tibiofemoral contact point could not be correlated with a different clinical outcome and higher incidence of anterior knee pain. This study further adds to the knowledge on possible differences between mobile- and fixed-bearing prostheses. Next to that, bad outcomes could not be explained by CP. LEVEL OF EVIDENCE: Case series, Level IV.
Entities:
Keywords:
Clinical results; Contact point; Fixed bearing; Mobile bearing; Total knee arthroplasty
Authors: Stefan J M Breugem; Inger N Sierevelt; Matthias U Schafroth; Leendert Blankevoort; Gerard R Schaap; C Niek van Dijk Journal: Clin Orthop Relat Res Date: 2008-06-04 Impact factor: 4.176
Authors: B L Fransen; D C van Duijvenbode; M J M Hoozemans; B J Burger Journal: Knee Surg Sports Traumatol Arthrosc Date: 2016-06-20 Impact factor: 4.342
Authors: Michel P Bonnin; Arnoud de Kok; Matthias Verstraete; Tom Van Hoof; Catherine Van Der Straten; Mo Saffarini; Jan Victor Journal: Knee Surg Sports Traumatol Arthrosc Date: 2016-09-26 Impact factor: 4.342