The Tibial Longitudinal Rotation During Flexion After Medial Unicondylar Arthroplasty

Objective: To study result of unicondylar arthroplasty for the treatment of medialcompartmental osteoarthritis of knee. To validate the credibility of the measure of the tibiallongitudinal rotation during flexion with CT three-dimensional imaging,and to ivestigatethe tibial longitudinal rotation during flexion after medial unicondylar arthroplasty.Methods: Seventeen patients with medial compartmental osteoarthritis of knee had beentreated by unicondylar arthroplasty from Dec,2004 toSep,2005..Patient selection,surgicaltechnique,postoperational treatment and short-term results were analyzed. Ten normalknees from five adults and ten patients with unilateral medial compartmental osteoarthritisof knee had been treated by unicondylar arthroplasty were included,their tibial longitudinalrotation during flexion were measured with CT three-dimensional imaging,The results ofthe two groups were intercompared.Results: .All of the patients got followed up .Had no any complication.Average HSS scorewas 96. Ten normal knees flexed at 30°,60°,90°and 120°position,tibia average internalrotated 4.1°+1.2°,2.1°+1.2°,3°+2.1°and 9.5°+1.6°respectively,was the same to the resultsof literatrues.Ten knees after UKA flexed at 30°,60°and 90°position,tibia average internalrotated 4.2°+1.2°,2.2°+1.6°and 3.2°+1.5°respectively.Compared the results of the two groups with Paired-Samples T Test,flexed at 30°,60°and 90°position respectively, thedegrees of tibial average internal rotation have no different(P>0.5).Conclusion: The short-term result of unicondylar arthroplasty for unicompartmentalosteoarthritis of knee is excellent. Patient selection and surgical technique are the mostimportant factors affecting the final result. 15°~20°varus of the knee is not contraindicationto UKA.If the later subluxation is lesser than 6mm,it can be corrected by UKA.CTthree-dimensional imaging is a effectual method to ivestigate the tibial longitudinal rotationduring flexion,especially after arthroplasty.Medial UKA has no effect on the tibiallongitudinal rotation during flexion.