Department of Joint Surgery, Institute of Orthopedics, The 940th Hospital of PLA Joint Logistics Support Force, South Binhe Road, No. 333, Lanzhou City, Gansu Province, 730050, PR China.
Department of Joint Surgery, Institute of Orthopedics, The Dingxi People's Hospital, Anding Road, Anding District, No. 22, Dingxi City, Gansu Province, 730050, PR China.
J Orthop Surg Res. 2021 Jan 7;16(1):17. doi: 10.1186/s13018-020-01985-z.
Dorr type C femoral bone exhibits a wide, stovepipe-shaped femoral canal, and thin cortices in the proximal femur. Dorr C bone combined with severe osteoporosis is an important challenge in primary hip arthroplasty. In this study, we assessed the effects of short metaphyseal fitting cementless stems on preformatted primary total hip arthroplasties in young adult osteoporotic patients with this femoral presentation.
A total of 42 hip arthroplasties were performed in 35 young patients (range 20 to 36 years) using a short Tri-lock bone preservation metaphyseal-fitting cementless femoral component between 2012 and 2017. The mean age at surgery of the 27 male (33 hips) and 8 female (9 hips) patients was 27.5 years (range 20.3 to 35.8 years). The mean body mass index (BMI) was 20.2 kg/m (range, 16.8-23.2 kg/m). According to Dorr's criteria, all 42 femora were classified as type C bone and all femurs suffered from severe osteoporosis (Singh index ≤ 3).
The mean follow-up period was 5.5 years (range 3.0 to 8.0 years). The clinical and functional results improved for the Harris hip score, WOMAC, and UCLA activity scores. The Harris Hip score improved from 48.0 ± 8.0 (range 38.0 to 61.0) preoperatively to 87.0 ± 9.0 (range 77.0 to 92.0) at 12 months after surgery and 91.0 ± 8.0 (range 85.0 to 98.0) at final follow-up. The preoperative UCLA activity score was 3.0 ± 0.5 points (range, 1.0-4.0 points), which significantly improved to 7.5 ± 0.7 points (range 6.0 to 8.0 points) at the final follow-up. No patient exhibited thigh pain at the final follow-up. The mean stem-to-canal fill percentages were 97% ± 2.1% (anteroposterior view at midstem). For stem alignment, 40 hips (95.2%) of the femoral stem were positioned neutrally to 3° of varus with reference to the femoral shaft axis. The remaining two were positioned at 4° varus to 4° valgus. Radiographic evaluation showed good osteointegration of the implants in follow-up.
Based on the tapered-wedge design and proximal porous coating, the shortened tapered conventional stem can achieve reliable stability through neck filling and metaphyseal fixation, which does not depend on the isthmus hoop stress. This stem was suitable in severe osteoporotic patients with type C bones in young adults who presented with a correspondingly straightened femoral canal with a wide isthmus and thin cortex.
Dorr C 型股骨具有宽大的、管状样的股骨髓腔，以及近端股骨皮质较薄。Dorr C 型骨合并严重骨质疏松是初次髋关节置换术的重要挑战。本研究旨在评估短柄、骨水泥型非骨水泥假体在伴有这种股骨形态的年轻成人骨质疏松患者初次全髋关节置换术中的应用效果。
2012 年至 2017 年，我们对 35 例（年龄 20 至 36 岁）年轻患者的 42 髋采用 Tri-lock 短柄骨保存型非骨水泥股骨假体进行初次全髋关节置换术。27 例男性（33 髋）和 8 例女性（9 髋）患者的平均手术年龄为 27.5 岁（范围 20.3 至 35.8 岁）。平均 BMI 为 20.2kg/m（范围 16.8-23.2kg/m）。根据 Dorr 分型标准，所有 42 例股骨均为 C 型骨，且均有严重骨质疏松（Singh 指数≤3）。
平均随访时间为 5.5 年（范围 3.0 至 8.0 年）。Harris 髋关节评分、WOMAC 评分和 UCLA 活动评分的临床和功能结果均得到改善。Harris 髋关节评分由术前的 48.0±8.0（范围 38.0 至 61.0）分提高至术后 12 个月的 87.0±9.0（范围 77.0 至 92.0）分和末次随访时的 91.0±8.0（范围 85.0 至 98.0）分。术前 UCLA 活动评分 3.0±0.5 分（范围 1.0 至 4.0 分），末次随访时显著提高至 7.5±0.7 分（范围 6.0 至 8.0 分）。末次随访时无患者出现大腿疼痛。柄-髓腔填充百分比的平均值为 97%±2.1%（在中柄位行前后位 X 线片测量）。对于股骨柄的对线，40 髋（95.2%）股骨柄的位置为中立位至 3°轻度内翻，以参考股骨干轴线。其余两髋的位置为 4°内翻至 4°外翻。影像学评估显示在随访过程中植入物具有良好的骨整合。
基于锥形设计和近端多孔涂层，缩短的锥形常规柄可通过颈填充和骨干固定实现可靠的稳定性，而不依赖于峡部的环向应力。这种假体适用于伴有宽大峡部和皮质较薄的管状样股骨髓腔的年轻 C 型骨骨质疏松患者。
