Clinical Investigation

Tibial Slope Changes Following Dome Type High Tibial Osteotomy

  • Emre ÇULLU
  • Semih AYDOGDU
  • Bülent ALPARSLAN
  • Hakki SUR

Received Date: 17.12.1999 Accepted Date: 25.03.2000 Meandros Med Dent J 2000;1(1):27-32

Purpose: Tibial slope (TS) contributes to knee biomechanics as an important factor in such a way that its changes after high tibial osteotomy (HTO) may affect ligament function and kinematics of the knee. We aimed to investigate whether there is a change of tibial slope following dome type high tibial osteotomy. Patients and Method: Fourty patients operated on for unilateral medial gonarthrosis by dome-type HTO and external fixation combination were reviewed retrospectively for the changes of TS. Four different measurement methods [anterior tibial cortex (ATC), tibial proximal anatomical axis (TPAA), posterior tibial cortex (PTC), fibular proximal anatomical axis (FPAA)] were used. Patients were grouped according to the length of follow-up period and to the corrections postoperatively obtained. Correlation between different parameters was also searched. Results: Preoperative mean ATC angle was 11.2°, TPAA angle was 7.5°, PTC angle was 5.6°, FPAA angle was 8.2°. Postoperative mean ATC angle was 7.9°, TPAA angle was 4.8°, PTC angle was 2.2°, FPAA angle was 3.7° after mean 55 months follow-up. All the parameters used for TS measurement decreased postoperatively. No significant difference in TS among groups with different durations of follow-up could be found. Conclusion: Patients with hypocorrection (or recurrence of deformity) had a relatively larger decrease in TS, even in the form of anterior slope than those with normo- or hypercorrection. The higher the degree of postoperative femoro-tibial valgus, the higher was the degree of tibial posterior slope. All the measurement techniques showed a significant correlation both pre- and postoperatively. Tibial slope measured by 4 different techniques showed a significant decrease after dome-type HTO. Dome-type HTO may also change significantly as seen in other HTO techniques, although it does not depend on a bone wedge removal or addition. This “parasitically” sagittal plane changes should be taken into account for subsequent reconstructive procedures such as total knee arthroplasty.

Keywords: Tibia, osteotomy, tibial slope