Department of Orthopedics, Shanghai University of Medicine & Health Sciences Affiliated Zhoupu Hospital, Shanghai, China.
Department of Orthopedics, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical College, Zhejiang, China.
BMC Musculoskelet Disord. 2024 Jan 30;25(1):103. doi: 10.1186/s12891-024-07199-2.
The role of acetabular and femoral component positions with respect to the risk of post-operative instability and dislocation remains debated. In this study, we aimed to identify potential risk factors for early dislocation following primary total hip arthroplasty (THA) for displaced intracapsular femoral neck fractures (FNF) using radiological measurements.
We retrospectively analyzed data for patients who underwent cementless primary THA for FNF using a posterolateral approach between January 2018 and December 2021. Follow-up duration, age, sex, affected side, and mean time from THA to dislocation were recorded. Leg-length inequality, abductor lever arm, vertical and horizontal femoral offsets, vertical and horizontal hip centers of rotation, abduction, anteversion of the acetabulum and femoral prosthesis, and combined anteversion were measured.
The study sample included 17 men and 34 women, with 21 and 30 patients undergoing left- and right-hip operations, respectively. The mean patient age was 70.18 ± 7.64 years, and the mean follow-up duration was 27.73 ± 13.52 months. The mean time between THA and dislocation was 1.58 ± 0.79 months. Seven patients (13.73%) sustained posterior dislocation of the hip. The abduction angle (36.05 ± 6.82° vs. 45.68 ± 8.78°) (p = 0.008) and anteversion of the femoral prosthesis (8.26 ± 4.47° vs. 19.47 ± 9.01°) (p = 0.002) were significantly lower in the dislocation group than in the control group. There were no significant differences in other parameters.
Insufficient stem antetorsion combined with lower abduction angle of the acetabular component were associated with a high risk of dislocation, especially in patients with deep flexion or internal rotation of the flexed hip joint and knees, or in patients with a stiff spine or anterior pelvic tilt, impingement may then occur in the neck of the prosthesis and cup component, ultimately resulting in posterior dislocation. These findings could remind surgeons to avoid simultaneous occurrence of both in THA surgery. These results provide new insight into risk factors for hip dislocation in patients undergoing primary THA for FNF and may aid in reducing the risk of instability and dislocation.
Prospective comparative study Level II.
髋臼和股骨部件位置与术后不稳定和脱位风险的关系仍存在争议。在这项研究中，我们旨在通过影像学测量来确定使用后外侧入路行非骨水泥初次全髋关节置换术（THA）治疗移位型囊内股骨颈骨折（FNF）患者术后早期脱位的潜在危险因素。
我们回顾性分析了 2018 年 1 月至 2021 年 12 月期间使用后外侧入路行 FNF 非骨水泥初次 THA 的患者数据。记录随访时间、年龄、性别、患侧、THA 至脱位的平均时间。记录下肢长度不等、外展肌臂长、垂直和水平股骨偏移量、垂直和水平髋关节旋转中心、外展角、髋臼和股骨假体前倾角以及联合前倾角。
本研究样本包括 17 名男性和 34 名女性，左髋和右髋手术分别为 21 例和 30 例。患者平均年龄为 70.18±7.64 岁，平均随访时间为 27.73±13.52 个月。THA 至脱位的平均时间为 1.58±0.79 个月。7 例（13.73%）发生髋关节后脱位。脱位组患者的外展角（36.05±6.82° vs. 45.68±8.78°）（p=0.008）和股骨假体前倾角（8.26±4.47° vs. 19.47±9.01°）（p=0.002）显著低于对照组。其他参数无显著差异。
股骨柄的初始扭转不足与髋臼部件的较低外展角与脱位风险增加有关，尤其是在髋关节处于深屈或内旋位、膝关节弯曲、或脊柱僵硬、骨盆前倾的患者中，假体颈部和杯组件可能发生撞击，最终导致后脱位。这些发现可以提醒外科医生在 THA 手术中避免同时出现这两种情况。这些结果为初次 THA 治疗 FNF 患者髋关节脱位的危险因素提供了新的认识，并可能有助于降低不稳定和脱位的风险。
前瞻性比较研究 II 级。
