Jørgensen Peter Bo, Homilius Morten, Koppens Daan, Hansen Torben Bæk, Stilling Maiken
Department of Orthopaedics, University Clinic for Hand, Hip and Knee Surgery, Gødstrup Hospital; Department of Orthopaedics, Aarhus University Hospital, Denmark.
Department of Orthopaedics, University Clinic for Hand, Hip and Knee Surgery, Gødstrup Hospital, Denmark.
Acta Orthop. 2025 Sep 2;96:656-663. doi: 10.2340/17453674.2025.43907.
The new Tri-Lock bone -preserving stem with a collarless proximal-coated tapered-wedge design was compared with a classic well-proven collarless proximal-coated long and round-tapered design. Our primary aim was to compare femoral stem fixation (subsidence) of the Tri-Lock stem with the classic Summit stem, and secondarily to compare the change in periprosthetic bone mineral density (BMD) and PROMS between stem groups.
In a patient-blinded randomized controlled trial, 52 patients at mean age 60 (SD 6) received cementless Tri-Lock (n = 26) or Summit (n = 26) femoral stems with a cementless Pinnacle cup, a cross-linked polyethylene liner, and a CoCr head. Patients were followed for 5 years with radiostereometric analysis (RSA), dual-energy X-ray absorptiometry (DXA), and patient-reported outcome measures (PROMs). We measured mean (CI) values of migration and periprosthetic bone mineral density and calculated between group differences.
At 2-year follow-up, the mean difference in subsidence was 0.14 mm (95% confidence interval [CI] -0.27 to 0.56) and below the chosen minimal clinically important difference of 0.6 mm. At 5-year follow-up, for the Tri-Lock and Summit stems, the mean subsidence was 0.38 (CI 0.04-0.72) and 0.24 (CI 0.09-0.57), and the mean retroversion was 1.68° (CI 0.80-2.55) and 1.53° (CI 0.68-2.37), respectively. There was initial periprosthetic BMD loss for both stems. At 5-year follow-up, the mean metaphyseal bone loss was minimal for the Tri-Lock stem (zone 1: -2.8% vs -11.5%) while the Summit stem preserved the medial diaphyseal bone better (zone 6: -7.1% vs -13.6%). At the medial stem tip, BMD was increased with the Summit stem (zone 5: +3.4% vs -1.5%). At 5-year follow-up, median EQ5D was 1 in both groups and median Oxford Hip Score was 47 (Tri-Lock) and 45 (Summit) with no statistical significant differences between groups.
The Tri-Lock and the Summit stems displayed similar migration until mid-term follow-up. At 3 months both stems had lost metaphyseal periprosthetic bone mineral density (BMD). During the following years, the new design regained more metaphyseal BMD. Contrarily, the long and round-tapered stem design regained or even increased diaphyseal BMD. PROM scores improved beyond the reference level for both groups.
将新型的无领近端涂层锥形楔形设计的Tri-Lock保骨柄与经充分验证的经典无领近端涂层长圆形锥形设计的柄进行比较。我们的主要目的是比较Tri-Lock柄与经典Summit柄的股骨柄固定情况（下沉），其次是比较假体周围骨密度（BMD）变化以及两组柄之间的患者报告结局测量指标（PROMs）。
在一项患者盲法随机对照试验中，52例平均年龄为60岁（标准差6岁）的患者接受了无骨水泥的Tri-Lock柄（n = 26）或Summit柄（n = 26），同时使用无骨水泥的Pinnacle髋臼杯、交联聚乙烯内衬和钴铬合金股骨头。采用放射立体测量分析（RSA）、双能X线吸收法（DXA）和患者报告结局测量指标（PROMs）对患者进行了5年的随访。我们测量了迁移和假体周围骨密度的均值（可信区间）值，并计算了组间差异。
在2年随访时，下沉的平均差异为0.14 mm（95%可信区间[CI] -0.27至0.56），低于选定的最小临床重要差异0.6 mm。在5年随访时，对于Tri-Lock柄和Summit柄，平均下沉分别为0.38（CI 0.04 - 0.72）和0.24（CI 0.09 - 0.57），平均后倾角分别为1.68°（CI 0.80 - 2.55）和1.53°（CI 0.68 - 2.37）。两种柄在假体周围均有初始骨密度丢失。在5年随访时，Tri-Lock柄的平均干骺端骨丢失最小（区域1：-2.8%对-11.5%），而Summit柄在骨干内侧骨的保存方面更好（区域6：-7.1%对-13.6%）。在柄的内侧尖端，Summit柄的骨密度增加（区域5：+3.4%对-1.5%）。在5年随访时，两组的EQ5D中位数均为1，牛津髋关节评分中位数分别为47（Tri-Lock）和45（Summit），两组之间无统计学显著差异。
在中期随访之前，Tri-Lock柄和Summit柄显示出相似的移位情况。在3个月时，两种柄均出现了干骺端假体周围骨密度（BMD）丢失。在随后的几年中，新设计的柄重新获得了更多的干骺端BMD。相反，长圆形锥形柄设计重新获得甚至增加了骨干BMD。两组的PROM评分均提高到了参考水平以上。
