Abstract
Introduction
This study investigates the effect of Rivaroxaban (Bayer HealthCare) on early post-operative stiffness in primary total knee replacement.
Methods
The anticoagulant of choice for total knee arthroplasty in our Department was changed from Enoxaparin to Rivaroxaban in September 2009. We reviewed a consecutive, multi-surgeon, multi-implant series of primary total knee replacements for a 6 month period prior to (group A) and after (group B) the treatment change. All patients were reviewed by an independent Clinical Specialist Physiotherapist at 6 weeks post-surgery, where the range of movement was recorded prospectively using a goniometer. A stiff knee replacement was defined as one with 15 degrees of extension deficit or flexion to less than 75 degrees at 6 week follow up. All data was analysed on an intention to treat basis.
Results
There were 76 patients in group A and 58 in group B. There were 9 stiff knees in group A (11.8%) of which 4 had an extension deficit and 5 had limited flexion. There were 11 stiff knees in group B (19.0%) of which 7 had an extension deficit and 4 had limited flexion. No patient in either group had both an extension deficit and limited flexion as defined by our criteria. 1 patient in group A and 2 in group B underwent manipulation in theatre for stiffness.
Conclusion
We conclude that Rivaroxaban appears to increase stiffness at 6 weeks following total knee replacement. We postulate that this may be due to increased soft tissue tension from haematoma or serous discharge.
