Change of anatomic configuration of proximal tibia following high tibial osteotomy

[Objective]To measure the change of anatomic configuration of proximal tibial after high tibial osteotomy and probe its clinical consequences.[Method]From 2001 to 2005,there were 59 knees of 35 patients with medial unicompartmental osteoarthritis treated with closing-wedge high tibial osteotomy.Anatomic configuration of proximal tibia were measured both pre and postoperatively on radiographs.They included posterior slope angle of proximal tibia,tibial angle,lateral shift of articular surface of proximal tibial and level of the joint line.The alteration of the above features was calculated and analyzed statistically with paired t test.[Result]The mean tibial posterior slope angle were(8.9°±2.6°)preoperatively and(5.0°±2.3°)postoperatively.The tibial posterior slope angle was averagely decreased about(3.9°±1.7°).Tibial angle were(99.1°±4.3°)and(91.1°±3.8°)before and after high tibial osteotomy respectively.Lateral shift of articular surface of proximal tibial were(46.2±3.6)% and(53.1±3.9)% in pre and postopratively.Level of joint line was(41.2±3.6)mm and(38.0±3.2)mm in pre and postopratively.Statistical analysis indicated that there was significant difference of posterior slope angle or tibial angle or lateral shift of articular surface of proximal tibial or level of joint line between pre and post operative(P0.01).[Conclusion]The anatomic configuration of proximal tibial will change after high tibial osteotomy.These changes may exert negative effect on the results of total knee arthroplasty after high tibial osteotomy.Thorough understanding of the causes and consequences of these changes helps refining the techniques of high tibial osteotomy and preoperative planning of total knee arthroplasty if it is needed.