Journal of Pediatric Orthopaedics - 2026-05-05 - Journal Article
Is the Bernese Periacetabular Osteotomy Safe for the Treatment of Acetabular Dysplasia When the Triradiate Cartilage is Still Open? A Preliminary Study.
Pun SY, Kha ST, Park MO, Richey AE, Pham NS, Millis MB
Topics
Key Takeaway
PAO in patients aged 8–13 with open triradiate cartilage achieved a mean 21-degree LCEA improvement maintained at 3.8-year follow-up, but caused premature triradiate closure in 38.5% of cases.
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Summary
This retrospective case series evaluated PAO outcomes in 13 patients aged 8–13 with hip dysplasia and open triradiate cartilage, a historically contraindicated population. Mean LCEA improved 21.08 degrees postoperatively (5.61° to 26.69°, p<0.01), maintained at final follow-up (23.14°). Premature triradiate closure occurred in 5/13 patients (38.5%), with no intra-articular fractures, nonunions, or Tönnis grade progression observed.
Key Limitation
The 38.5% rate of premature triradiate closure is clinically significant but the study lacks sufficient follow-up duration and sample size to determine whether this complication produces measurable acetabular growth disturbance or functional deficit at skeletal maturity.
Original Abstract
BACKGROUND
Periacetabular osteotomy (PAO) has historically been contraindicated in children with hip dysplasia and open triradiate cartilage because of concerns that osteotomy through the triradiate might disrupt acetabular development. This preliminary study reports early outcomes of PAO for hip dysplasia in patients approaching skeletal maturity (aged 8 to 12 y or younger) with open triradiate cartilage.
METHODS
We performed a retrospective review of patients with hip dysplasia and open triradiate cartilage who underwent PAO between 1994 and 2019. Primary outcomes included changes in lateral center edge angle (LCEA), anterior center edge angle (ACEA), and acetabular index (AI), discontinuity along Shenton's line, extrusion index, triradiate width, and Tonnis grade preoperatively, postoperatively, and at final follow-up. Secondary outcomes included comparisons of radiographic parameters between the operative hip and the contralateral nonoperative hip, preoperative and postoperative patient-reported outcomes, and complications, including intraoperative intra-articular fractures, osteotomy nonunion, and premature triradiate closure. Descriptive statistics characterized the study population. Linear mixed-effects regression models and Cochran Q tests compared clinical and radiographic outcomes preoperatively, postoperatively, and at final follow-up. Differences between operative hips and contralateral nonoperative hips were analyzed using paired t tests or Wilcoxon signed-rank tests.
RESULTS
Thirteen patients were included. The mean age was 11.04 years (range: 8.05 to 12.82 y), and the mean follow-up was 3.79 years (range: 0.51 to 8.39 y). The mean LCEA increased 21.08 degrees immediately after PAO (preoperative 5.61±10.41 degrees; postoperative 26.69±8.82 degrees; P <0.01). This change was maintained at final follow-up (23.14±9.14 degrees; P <.01). Premature triradiate closure occurred in 5/13 patients (38.5%). No hips progressed in Tonnis Grade during the study period. Neither intra-articular fracture nor osteotomy nonunion was noted.
CONCLUSIONS
This preliminary study demonstrates that PAO can safely treat hip dysplasia in young adolescents with open triradiate cartilage, with good short-term outcomes. Despite premature triradiate closure in 38%, immediate postoperative correction of acetabular dysplasia remained satisfactory at final follow-up. Further studies are warranted to determine long-term outcomes.
LEVEL OF EVIDENCE
Level IV-case series.