Background: 

Periacetabular osteotomy (PAO) remains the gold-standard treatment for acetabular dysplasia in skeletally mature patients with preserved cartilage. The purpose of this multicenter cohort study was to delineate the long-term radiographic natural history of the dysplastic hip following PAO based on the final position of the acetabular fragment.

Methods: 

We evaluated patients who underwent PAO performed by 4 hip preservation surgeons to treat acetabular dysplasia with or without concomitant retroversion from 1996 to 2012 at 3 academic institutions. There were 288 patients with a mean clinical and radiographic follow-up of 9 years (range, 5 to 21 years). Postoperative radiographs made at the first clinical visit were used to determine if the acetabular fragment fell into a safe zone according to the absence of retroversion, a lateral center-edge angle (LCEA) of 25° to 40°, an anterior center-edge angle (ACEA) of 25° to 40°, and a Tönnis angle of 0° to 10°. Every available subsequent radiograph was assessed for degenerative changes by the Tönnis classification (grades 0 to 3). The time to progression was analyzed using Cox proportional hazards regression and multistate modeling.

Results: 

Only the absence of retroversion was independently associated with a decreased risk of progressing at least 1 Tönnis grade during follow-up: hazard ratio (HR), 0.60 (95% confidence interval [CI], 0.38 to 0.94; p = 0.025). Achieving the ACEA safe zone yielded the greatest time increase for remaining in Tönnis grade 0 or 1 (43 years for having an ACEA in the safe zone compared with 28 years for not having an ACEA in the safe zone), followed by the absence of retroversion (34 years for the absence of retroversion compared with 24 years for the presence of retroversion). However, attaining the Tönnis angle or LCEA safe zones did not delay progression. The achievement of additional safe zones generally increased the length of time that patients spent in Tönnis grade 0 or 1: 25 years for 0 safe zones, 36 years for 1 safe zone, 29 years for 2 safe zones, 37 years for 3 safe zones, and 44 years for 4 safe zones.

Conclusions: 

This study demonstrates the importance of achieving appropriate acetabular reorientation to enhance the longevity of the native hip following PAO. Although the LCEA and the Tönnis angle are the most common metrics used to assess appropriate acetabular correction, this study shows that adequately addressing retroversion and the ACEA has a greater impact on improving the natural history.

Level of Evidence: 

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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达到目标：基于髋臼周围截骨术后实现髋臼安全区的髋关节自然史。

 背景：

髋臼周围截骨术 (PAO) 仍然是保留软骨的骨骼成熟患者髋臼发育不良的金标准治疗方法。这项多中心队列研究的目的是根据髋臼碎片的最终位置描绘 PAO 后髋关节发育不良的长期放射学自然史。

 方法：

我们评估了 1996 年至 2012 年间在 3 个学术机构接受由 4 名髋关节保留外科医生实施的 PAO 治疗髋臼发育不良（伴有或不伴有后倾）的患者。 288 名患者的平均临床和影像学随访时间为 9 年（范围为 5 至 21 年）。术后第一次临床就诊时拍摄的X光片用于根据是否存在后倾、横向中心边缘角（LCEA）25°至40°、前中心边缘角来确定髋臼碎片是否落入安全区(ACEA) 为 25° 至 40°，Tönnis 角为 0° 至 10°。每张可用的后续射线照片均按照 Tönnis 分类（0 至 3 级）评估退行性变化。使用 Cox 比例风险回归和多状态模型分析进展时间。

 结果：

只有没有逆转与随访期间进展至少 1 Tönnis 级的风险降低独立相关：风险比 (HR)，0.60（95% 置信区间 [CI]，0.38 至 0.94；p = 0.025）。达到 ACEA 安全区后，保持 Tönnis 0 级或 1 级的时间增加最多（在安全区有 ACEA 的时间为 43 年，而在安全区没有 ACEA 的为 28 年），其次是没有逆转（没有后倾的情况为 34 年，而有后倾的情况为 24 年）。然而，达到 Tönnis 角或 LCEA 安全区并不会延迟进展。获得额外安全区通常会增加患者在 Tönnis 0 级或 1 级的时间长度：0 个安全区为 25 年，1 个安全区为 36 年，2 个安全区为 29 年，3 个安全区为 37 年， 4个安全区为44年。

 结论：

这项研究证明了在 PAO 后实现适当的髋臼重新定向对于延长原生髋关节寿命的重要性。尽管 LCEA 和 Tönnis 角是用于评估适当髋臼矫正的最常用指标，但本研究表明，充分解决后倾和 ACEA 对改善自然史具有更大的影响。

 证据级别：

治疗等级IV 。有关证据级别的完整描述，请参阅作者须知。