多孔钽棒植入治疗早中期股骨头坏死的生存率分析和预后因素评估

Survivor rate and prognostic factors of porous tantalum rob implants for the treatment of moderate avascular necrosis of femoral head

背景：多孔钽棒植入已成为治疗早中期股骨头坏死（ANFH）保存关节的主要方法之一,但术后临床疗效仍存在较大争议,同时一些相关因素也会影响术后疗效。目的：探讨多孔钽棒植入治疗早中期ANFH的中期生存数据,并确定转归至全髋关节置换术（THA）的独立预后因素。方法：将2009年4月至2011年7月进行的前瞻性、连续性接受钽棒植入治疗的SteinbergⅠ、Ⅱ期ANFH患者42例（52髋）作为多孔钽棒组;将2007年4月至2009年3月进行的回顾性、连续性髓芯减压打压植入人工骨填充颗粒的SteinbergⅠ、Ⅱ期ANFH患者36例（49髋）作为复合人工骨材料组。记录人口统计学和基线特征包括年龄、性别、病因、单双侧发病、相关慢性系统性疾病、Steinberg分期、术前Harris评分、伴有股骨头骨髓水肿和骨坏死病灶大小等。记录术中失血量、输血情况,记录术后住院时间、髋关节Harris评分和累计生存率。结果：术前两组人口统计学和基线特征差异无统计学意义。多孔钽棒组患者平均随访（48.2±4.5）个月（38-62个月）,复合人工骨材料组患者平均随访（71.6±5.1）个月（67-85个月）。末次随访时,多孔钽棒组Harris评分为（84.18±2.35）分,复合人工骨材料组Harris评分为（76.34±2.67）分,两组患者髋关节Harris评分较术前均有显著提高,差异有统计学意义（P〈0.0001）。术后髋关节Harris评分多孔钽棒组提高（26.2±2.5）分,复合人工骨材料组提高（17.3±3.6）分,与复合人工骨材料组比较,多孔钽棒组提高幅度较大,差异有统计学意义（F=4.22,P=0.0426）。Kaplan-Meier生存曲线比较显示,随访62个月时,多孔钽棒组髋关节累计生存率为74.1%±9.5%,显著高于复合人工骨材料组髋关节的49.9%±10.8%（χ^2=3.912,P=0.048）。Cox比例风险模型显示,股骨头骨髓水肿（RR=7.090,P=0.003）、皮质激素使用（RR=3.599,P=0.007）、多孔钽棒植入（RR=0.306,P=0.012）为ANFH转归至THA的独立预后因素。结论：髓芯减压结合多孔钽棒植入治疗SteinbergⅠ、Ⅱ期ANFH可显著缓解髋关节疼痛、改善髋关节功能和提高髋关节生存率。对于未使用皮质激素,尤其是未伴有股骨头骨髓水肿的早中期ANFH,髓芯减压结合多孔钽棒植入可使髋关节获得更高的生存率,并能延迟或阻止THA的转归。

Background： The implantation of a porous tantalum rob is one of the main methods for the treatment of moderate avascular necrosis of femoral head（ANFH）, but the outcomes have been debated for years. And several correlation factors will also affect clinical outcomes.Objective： To investigate the mid- term survival of porous tantalum rob implants in patients with moderate ANFH, and to identify independent prognostic factors for conversion to total hip arthroplasty（THA）.Methods： Forty-two consecutive patients（52 hips） with Steinberg stage Ⅰ and Ⅱ osteonecrosis obtained from a prospective study were enrolled in experiment group. They underwent porous tantalum rob implantation between April 2009 and July 2011. Thirty-six consecutive patients（49 hips） with Steinberg stage Ⅰ and Ⅱ osteonecrosis obtained from a retrospective study were enrolled in control group. They were treated by core decompression and artificial bone grafting between April 2007 and March 2009. Demographics and baseline characteristics including age, sex, etiology, bilateral disease, associated chronic systemic disease, Steinberg stage, Harris hip score, accompanied with bone marrow edema of femoral head, and osteonecrotic lesion size were recorded. Intraoperative blood loss, transfusion, postoperative hospital stay, Harris hip scores and hip survival rates were also recorded.Results： There were no significant differences in the demographic or baseline characteristics between groups. The average duration of follow- up was（48.2 ± 4.5） months（range, 38- 62 months） in the experiment group and was（71.6 ± 5.1） months（range, 67- 85 months） in the control group. At the final follow- up, Harris hip scores were 84.18 ± 2.35 in the experiment group and were 76.34±2.67 in the control group, which were significantly higher than preoperative ones in both groups（P〈0.0001）. The amplification of Harris score in the experiment group was significantly greater than that in the control group（26.2 ± 2.5 vs 17.3 ± 3.6, F=4.22, P=0.0426）. A comparison of Kaplan- Meier curves showed a significantly higher survival rate for hips with implantation of the porous tantalum rob than those with artificial bone grafting（74.1%±9.5% vs 49.9%±10.8%, χ^2=3.912, P=0.048） at 62 months after surgery. The Cox proportional-hazard model revealed that bone marrow edema（RR=7.090, P=0.003）, corticosteroid intake（RR=3.599, P=0.007） and implantation of tantalum rob（RR=0.306, P=0.012） were the independent prognostic factors related to conversion into THA.Conclusions： Core decompression combined with implantation of porous tantalum rod can significantly relieve pain, improve function of hip joint, increase hip survival rate in patients with Steinberg stage Ⅰ and Ⅱ ANFH. For the patients without corticosteroid intake, especially for those without bone marrow edema, implantation of porous tantalum rod shows a high survival rate and a delay or prevention of conversion into THA.