In proximal tibial anterior closing wedge (slope changing) osteotomy lower starting points imply larger bone resection.

Background: Anterior closing wedge osteotomy (ACWO) for tibial slope correction is a validated procedure in revision anterior cruciate ligament reconstruction (ACLR). This study aims to determine how different starting points of the osteotomy affect the amount of bone resection in ACWO.

Hypothesis: We hypothesized that the lower osteotomy starting points in ACWO imply larger bone resection.

Patients and methods: A total 52 patients who underwent ACWO using infra-tuberosity technique in our institution were included in this study. Each of patients was simulated using additional two separate methods (based on osteotomy level: supra- and trans-tuberosity) based on lateral calibrated pre-operative X-rays of the whole tibia according to the post-operative correction angle. The resection height of the closing wedge, which corresponded to the base of the osteotomy, was measured and compared among the three groups.

Results: The mean actual pre-operative proximal posterior tibial angle (PPTA) was 75.8 ± 2.0°. Post-operatively, PPTA was 84.0 ± 0.6°, and correction angle was 8.2 ± 2.2°. The mean resection height in the supra-tuberosity group was 7.5 ± 0.2 mm, 8.0 ± 2.1 mm in the trans-tuberosity group, and 9.2 ± 2.1 mm in the infra-tuberosity group. There were significant differences between each approach (p ≦ 0.0001). Resection height was moderate positively correlated with the starting point of osteotomy (r = 0.33, 95%CI: 0.18-0.46, p < 0.0001).

Conclusion: This study suggests that selecting a distal starting point for the osteotomy in ACWO is directly proportional to the observed increase in bone resection, providing valuable insights for pre-operative planning. These findings are clinically relevant and will aid in preoperatively deciding approach in ACWO.

Level of evidence: IV; retrospective case-control study.