CGM Research Trust, Christchurch, South Island, New Zealand.
Department of Orthopaedic Surgery and Musculoskeletal Medicine, University of Otago, Christchurch, South Island, New Zealand.
J Bone Joint Surg Am. 2024 Mar 20;106(6):508-516. doi: 10.2106/JBJS.23.00449. Epub 2023 Dec 19.
Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long-term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in 3 morphologically different uncemented femoral stem designs to investigate whether any particular design resulted in better preservation of BMD.
A total of 119 patients were randomized to receive a proximally coated collarless dual-taper wedge stem, a proximally coated collarless anatomic stem, or a fully coated collarless triple-taper stem. All surgeries were performed via the posterior approach, with mobilization on the day of surgery. Dual x-ray absorptiometry scans (Lunar iDXA, GE Healthcare) assessed BMD across the 7 Gruen zones preoperatively and at 6 weeks and 2 years postoperatively; if available, the native contralateral femur was also assessed as a control. Patient-reported outcomes of pain, function, and health were also assessed at these follow-ups.
Averaged across all stems, BMD increased in zones 1 (2.5%), 2 (17.1%), 3 (13.0%), 5 (10%), and 6 (17.9%) at 2 years. Greater preservation of BMD was measured on the lateral cortex (zone 2) for both the dual-taper wedge and anatomic stems (p = 0.019). The dual-taper wedge stem also demonstrated preservation of BMD in the medial calcar (zone 7), while the anatomic and triple-taper stems declined in this region; however, the difference did not reach significance (p = 0.059). Averaged across all stems, BMD decreased in the mid-diaphysis region, distal to the stem tip (zone 4). All stems performed similarly at the time of final follow-up with respect to the patient-reported outcomes.
This study demonstrated maintenance of femoral BMD after use of 3 different cementless femoral stem designs, with all achieving excellent improvements in patient-reported outcomes. The stems designed to load the proximal metaphyseal region resulted in higher BMD in that region. No significant stress-shielding was observed; however, longer follow-up is required to elucidate the impact of this finding on implant survivorship.
Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.
股骨柄设计会影响假体周围骨密度（BMD），这可能会影响非骨水泥植入物在全髋关节置换术（THA）中的长期生存率。本研究的目的是检查 3 种形态不同的非骨水泥股骨柄设计的股骨近端 BMD，以研究任何特定设计是否能更好地保留 BMD。
共 119 例患者随机接受近端涂层无领双锥楔形柄、近端涂层无领解剖柄或全涂层无领三锥柄。所有手术均经后路进行，术后当天即可活动。双能 X 线吸收仪（Lunar iDXA，GE Healthcare）在术前、术后 6 周和 2 年时评估 7 个 Gruen 区的 BMD；如有可能，还将对健侧股骨进行评估作为对照。在这些随访中，还评估了患者的疼痛、功能和健康状况的报告结果。
所有柄平均而言，2 年后，BMD 在区域 1（2.5%）、2（17.1%）、3（13.0%）、5（10%）和 6（17.9%）增加。双锥楔形和解剖柄在外侧皮质（区域 2）上测量到更大的 BMD 保留（p = 0.019）。双锥楔形柄还在内侧股骨距（区域 7）保留了 BMD，而解剖柄和三锥柄在该区域则减少；然而，差异没有达到显著水平（p = 0.059）。所有柄平均而言，BMD 在柄尖端以下的骨干中部区域（区域 4）减少。所有柄在最后一次随访时的患者报告结果表现相似。
本研究表明，使用 3 种不同的非骨水泥股骨柄设计后，股骨 BMD 得到维持，所有患者的报告结果均有优异的改善。设计用于负荷近侧干骺端区域的柄导致该区域的 BMD 更高。未观察到明显的应力遮挡；然而，需要更长的随访时间来阐明这一发现对植入物存活率的影响。
治疗水平 I。请参阅作者说明，以获取完整的证据水平描述。
