Bernese peri-acetabular osteotomy performed with navigation and patient-specific templates is a reproducible and safe procedure.

Purpose: To present a novel surgical technique for the Bernese peri-acetabular osteotomy (PAO) using electromagnetic navigation (EMN) and patient-specific templates (PST), and to evaluate it against the traditional fluoroscopic technique.

Methods: We included 40 dysplastic hips. All PAOs were performed using PST and EMN. We recorded learning-related complications. For the purpose of acetabular fragment correction analysis, patients were divided into two groups. In the study group (EMN group, 30 hips), the acetabular fragment was reoriented with the help of EMN. In the control group (XR group, 10 hips), the acetabular fragment was reoriented using fluoroscopy. We compared the difference between the planned and achieved position of the acetabular fragment and outcomes between both groups.

Results: Two major complications occurred in four PAOs in the XR group only (first ten PAOs). The average absolute difference in planned and achieved lateral centre -edge angle (LCEA) and acetabular index (AI) was 1.2° ± 1.5° and 1.1° ± 2° for the EMN and 7° ± 6.1° and 6.3° ± 6.3° for the XR group (p = 0.02; p = 0.03). The average surgery duration was 183 ± 32 minutes for the EMN and 203 ± 42 minutes for the XR group (p = 0.19). At the last follow-up, the average Harris Hip Score (HHS) value was 88 ± 12 in the EMN and 86 ± 14 in the XR group (p = 0.84).

Conclusions: Our study indicates that PAO performed with EMN and PST seems to be a safe and reproducible procedure with a short learning curve. Additionally, navigated reorientation of the acetabular fragment is significantly more accurate than the fluoroscopic technique.