[The effect of tibiofemoral angle changes on the results of dome osteotomy]

We investigated the effect of tibiofemoral angle changes on the results of dome osteotomy in patients with medial compartment osteoarthritis of the knee.

The study included 23 knees of 22 patients (15 women, 7 men; mean age 60 years; range 37 to 73 years) who underwent high tibial dome osteotomy for medial compartment osteoarthritis. A simple modified Charnley external fixator was used for stabilization of the osteotomy. Based on the Ahlback classification, 15 knees had grade I, six knees had grade II, and two knees had grade III osteoarthritis. The patients were evaluated in three groups based on the postoperative tibiofemoral angles obtained; hence, a valgus angle of less than 8 degrees (4 knees), 8 degrees to 12 degrees (10 knees), and greater than 12 degrees (9 knees). Clinical evaluations were made using the American Knee Society scoring system. The mean follow-up period was 5.4 years (range 1 to 10 years).

The mean tibiofemoral angle was 4.4+/-2.9 degrees of varus (range 0 degrees to 10 degrees ) preoperatively, and 11+/-3.8 degrees of valgus (range 5 degrees to 18 degrees ) postoperatively. The mean correction loss at final evaluations was 2.7 degrees . The mean preoperative and postoperative knee scores were 37.7+/-15.8 (range 19 to 77) and 80.2+/-9.2 (range 51 to 93), respectively (p<0.001). The mean functional score increased from 52.3+/-18.8 (range 10 to 80) to 75.6+/-18.5 (range 35 to 100) at final analysis (p<0.001). The knee and functional scores did not differ significantly between three groups of patients having a different range of postoperative tibiofemoral angle (p>0.05).

Our results show that the alignment obtained after high tibial osteotomy does not influence knee and functional scores provided that it is within an acceptable range.