Yi Jiafeng, Xie Hongbin, Liu Yubo, Huang Yijian, Chai Wei, Kong Xiangpeng
School of Medicine, Nankai University, Tianjin, China.
Senior Department of Orthopedics, The Fourth Medical Center of PLA General Hospital, Beijing, China.
Orthop Surg. 2025 Aug;17(8):2313-2320. doi: 10.1111/os.70092. Epub 2025 Jun 17.
S-ROM prosthesis, one well-used femoral prosthesis in the patients with developmental dysplasia of the hip (DDH), has a skipping size of the distal stem diameter. The purpose of this study was to investigate whether its 2-mm incremental diameter could meet clinical needs for high-riding DDH patients.
Between July 2018 and December 2022, the Hartofilakidis type C DDH patients with S-ROM stem (9 or 11 mm) were retrospectively enrolled according to the inclusion criteria and exclusion criteria in our institute. The intraoperative femur fractures, the diameter of the femoral medullary cavity, the canal filling ratio of the S-ROM stem, the closure conditions of the stem slot, and the healing rate of subtrochanteric osteotomy were analyzed to evaluate the effect of stem design on clinical outcomes. Statistical analyses were conducted using independent samples t-tests, chi-square test, and logistic regression analysis with a significance threshold of p < 0.05.
A total of 95 patients (109 hips) were included in this study, including 60 hips with 9 mm S-ROM and 49 hips with 11 mm S-ROM. Compared with the 9 mm S-ROM group, the 11 mm S-ROM group presented nearly 5 times the intraoperative fracture rate (16.3%, 3.3%, p < 0.05). The mean diameter of the femoral medullary cavity in the 9 mm S-ROM group was 0.84 ± 0.20 mm and in the 11 mm S-ROM group was 1.03 ± 0.18 mm. The canal filling ratio in the 9 mm S-ROM group is significantly lower than that of the 11 mm S-ROM group. In the 11 mm S-ROM group, the filling ratio of the femoral medullary cavity of fracture hips was significantly higher than that in non-fracture hips.
The S-ROM design with a distal stem diameter increment of every 2 mm would increase the risk of intraoperative periprosthetic femoral fractures in high-riding DDH patients. It is necessary for a 1-mm increment of distal stem diameter in such patients.
Level III, retrospective comparative study.
S-ROM假体是发育性髋关节发育不良（DDH）患者常用的一种股骨假体，其远端柄直径存在跳档尺寸。本研究的目的是探讨其2毫米的直径增量是否能满足高位DDH患者的临床需求。
2018年7月至2022年12月，根据我院的纳入标准和排除标准，对采用S-ROM柄（9或11毫米）的Hartofilakidis C型DDH患者进行回顾性纳入。分析术中股骨骨折情况、股骨髓腔直径、S-ROM柄的髓腔填充率、柄槽的闭合情况以及转子下截骨的愈合率，以评估柄设计对临床结果的影响。采用独立样本t检验、卡方检验和逻辑回归分析进行统计分析，显著性阈值为p<0.05。
本研究共纳入95例患者（109髋），其中9毫米S-ROM组60髋，11毫米S-ROM组49髋。与9毫米S-ROM组相比，11毫米S-ROM组的术中骨折率几乎高出5倍（16.3%对3.3%，p<0.05）。9毫米S-ROM组股骨髓腔的平均直径为0.84±0.20毫米，11毫米S-ROM组为1.03±0.18毫米。9毫米S-ROM组的髓腔填充率显著低于11毫米S-ROM组。在11毫米S-ROM组中，骨折髋的股骨髓腔填充率显著高于未骨折髋。
远端柄直径每增加2毫米的S-ROM设计会增加高位DDH患者术中假体周围股骨骨折的风险。对于此类患者，远端柄直径增加1毫米是必要的。
III级，回顾性比较研究。
