Purpose: Tihial osteotomy for valgisaiion is a difficult procedure with a risk of over-correction or under-correction which can have significant aesthetic, functional and medicolegal consequences. In order to improve the precision, we adapted a navigation system to tihial osteotomy for valgisation. ITie purpose of the present work was to evaluate the feasibility and results of this technique.
Material and methods: From March to November 2001, we used the Orthopilot system lor 19 patients with gcnu varum. Mean patient age was 50.8±11.7 years (range 18-71). The indication for valgisation was genu varum, associated with joint degeneration (grade 1, 2, or 3 in the modified Ahlback classification) in 18. The aesthetic effect of genu varum was the only indication in one patient. Preoperativeh, the mean HKA was 173.73±3.24° (range 169-178). The mechanical axis was determined with Orthopilot before performing an open medial osteotomy for valgisation which was fixed temporarily with a metal wedge to control as needed lower limb alignment. Orthopilot enabled verification of the desired axis. When obtained, the metal wedge was removed and replaced by a wedge of tricalcium phosphate (Biosorb®. B-Pharm) of the same size. The osteotomy was stabilised with a screw plate. The objective was to obtain a femorotibial axis between 182° and 186°. i.e. 2° to 6° valgus.
Results: HKA measured peroperatively with Orthopilot was 174.05±3.06°, exactly the same as on the preoperative x-rays. After oseotomy, HKA was 183.47±1.07° (180°-184°)with Orthopilot. and 183.47±1.44°(179°-186°) on the x-rays. Eighteen knees were within the objective of 182°-186° giving a success rate of 94.7%.
Discussion: Computer-assisted tibial osteotomy for valgisation using Orthopilot is quite feasible. To have a valid assessment of this new method, results would have to be compared with a series performed without computer assistance.
H. Pichon, D. Saragaglia, C. Chaussard, D. Berne
Service de Chirurgie Orthopedique et
Traurnutologie du Sport, Hopital Sud, BP 185,
38042 Grenoble cedex 09, France
Copyright British Editorial Society of Bone & Joint Surgery 2004
Provided by ProQuest Information and Learning Company. All rights Reserved