Osteotomies for valgus deformity are much less frequent than those for varus deformity as evidenced by published series which are, on one hand, less numerous and on the other hand, based on far fewer cases. For genu varum deformity, it has been proved that navigation allows to reach easier the preoperative correction goal. Our hypothesis was that navigation for genu valgum could be as accurate as for genu varum deformity. The aim of this paper was to present the mid-term results of 29 computer-assisted osteotomies for genu valgum deformity performed between September 2001 and March 2013.

The series was composed of 27 patients (29 knees), 20 females and 7 males, aged from 15 to 63 years (mean age: 42.4+/−14.3 years). The preoperative functional status was evaluated according to the Lyshölm-Tegner score. The mean score was of 64+/−20.5 points (18–100). The stages of osteoarthritis were evaluated according to modified Ahlbäck's criteria. We operated on 12 stage 1, 9 stage 2, 5 stage 3 and 1 stage 4. 2 female patients had no osteoarthritis but a particularly unesthetic deformity (of which one was related to an overcorrected tibial osteotomy). The pre and postoperative HKA angle was measured according to Ramadier's protocol. We measured also the medial tibial mechanical angle (MTMA) and the medial femoral mechanical angle (MFMA). The mean preoperative HKA angle was 189.3°+/−3.9° (181° to 198°); the mean MFMA was 97.2° +/− 2.6° (93° to 105°) and the mean MTMA was 90.1° +/− 2.8° (86° to 95°). The goal of the osteotomies was to obtain an HKA angle of 179° +/− 2° and a MTMA of 90°+/2° in order to avoid an oblique joint line. We performed 24 femoral osteotomies (14 medial opening wedge and 10 lateral closing wedge) and 5 double osteotomies (medial tibial closing wedge + lateral opening wedge osteotomy). The functional results were evaluated according to Lyshölm-Tegner, IKS and KOO Scores, which were obtained after revision or telephone call.

We did not find any complication except a transient paralysis of the common fibular nerve. 23 patients (4 lost to follow-up) were reviewed at a mean follow-up of 50.9+/−38.8 months (6–144). The mean Lyshölm-Tegner score was 92.9+/−4 points (86–100), the mean KOO score 89.7+/−9.3 (68–100), the mean IKS ≪knee≫ score 88.7 +/−11.4 points (60 à 100) and the mean ≪function≫ score 90.6 +/−13.3 points (55–100). 22 of the 23 reviewed patients (25 knees) were very satisfied or satisfied of the result. Regarding the radiological results, the mean HKA angle was of 180.1°+/−1.9° (176° to 185°), the mean MFMA of 90.7°+/−2.5° (86°-95°) and the mean MTMA of 89.1°+/−1.9° (86°-92°). The preoperative goal was reached in 86.2% (25/29) of the cases for HKA angle and in 100% of the cases for MTMA when performing double level osteotomy (5 cases). At this follow-up, no patient was revised to TKA.

Computer-assisted osteotomies for genu valgum deformity lead to excellent results a mid-term follow-up. Navigation is very useful to reach the preoperative goal.