Significant slope reduction in ACL deficiency can be achieved both by anterior closing-wedge and medial open-wedge high tibial osteotomies: early experiences in 76 cases.

Purpose: It has been proven that a steep tibial slope (TS) is a risk factor for anterior cruciate ligament (ACL) injury and graft insufficiency after ACL reconstruction (ACLR). Recently, there is an increasing number of case series on slope decreasing osteotomies after failed ACLR utilizing different techniques and strategies. Goal of the present study is to report on early experiences with slope decreasing osteotomies in ACL deficient knees with special emphasis on the amount of slope correction, technical details, and complications; and to further analyze differences of slope corrections between sole sagittal as well as combined coronal and sagittal realignment procedures. In addition, we wanted to study if sole sagittal corrections change the coronal alignment.

Methods: Seventy-six patients with a minimum follow-up of 6 months were identified, who underwent a sole sagittal correction (anterior closed-wedge high tibial osteotomy (ACW-HTO)) or a combined procedure with an additional coronal realignment (medial open-wedge high tibial osteotomy (MOW-HTO)). In ACW-HTO, either infratuberosity or supratuberosity approaches were used. The medial TS was measured on lateral radiographs and the anatomical medial proximal tibial angle (aMPTA) was measured on anterior-posterior radiographs. Technical details and specific complications were recorded.

Results: Fifty-eight ACW-HTO and 18 MOW-HTO were performed. Regarding ACW-HTO, an infratuberosity (N = 48) or a supratuberosity (N = 10) approach was chosen. Sixty-seven patients had at least 1 previous ACLR. Mean TS changed from 14.5 ± 2.2° to 6.8 ± 1.9° (P < 0.0001). Mean TS of ACW-HTO was significantly reduced (14.6 ± 2.3° vs. 6.5 ± 1.9°; P < 0.0001), whereas in combined coronal and sagittal realignments, from 14.1 ± 1.9° to 7.6 ± 1.9° (P < 0.0001). The TS reduction in sole sagittal corrections was significantly higher compared to combined procedures (8.1 ± 1.6 vs. 6.4 ± 1.6°; P = 0.0002). Mean aMPTA in ACW-HTO changed from 87.1 ± 2.1° to 87.4 ± 2.8 (n.s.). However, there was a significant inverse correlation between the amount of sagittal correction and coronal alteration (r = - 0.29; P = 0.028). There was one late implant infection, which occurred 5.5 months after the index surgery.

Conclusions: ACW-HTO and MOW-HTO facilitate significant slope reduction with a low-risk profile in patients with ACL insufficiency and a high tibial slope. AOW-HTO does not significantly alter coronal alignment in the majority of patients.

Level Of Evidence: IV.