Fitzpatrick Daniel C, Sheerin Daniel V, Wolf Brian R, Wuest Thomas K
Slocum Center for Orthopedics and Sports Medicine, Eugene, OR, USA.
Iowa Orthop J. 2011;31:166-72.
To evaluate the clinical performance of the Dynamic Helical Hip System (DHHS) spiral blade relative to the Dynamic Hip Screw (DHS) lag screw.
Randomized prospective study.
One level-2 trauma center and one level-3 trauma center.
Fifty-one consecutive patients were recruited into the trial. Inclusion criteria included patients over 50 years of age with AO/OTA 31A1 or 31A2 fracture.
Surgeries were performed by one of 15 participating community orthopaedic surgeons. The patients were randomized to either a DHHS or DHS implant. Follow-up occurred at two weeks and six weeks and then at six-week intervals until healing occurred.
Primary outcome variables included sliding of die implant on the final AP radiographs, failure by cut-out and implant failure.
There were 24 patients in the DHS group and 27 in the DHHS group. There was no difference in age, gender, ASA score, fracture classification or in the quality of reduction measured on the immediate postoperative radiographs (p=0.28) between the two groups. The tip apex distance was 18.7 mm in the DHHS group and 18.5 mm in the DHS group (p=0.40). The DHHS group had average blade sliding of 7.4 mm while the DHS group had an average lag-screw sliding of 7.7 (p=0.45). The DHHS group had two failures by central protrusion of the blade through the femoral head without significant varus collapse or superior migration. One was revised to a DHS and healed, the other was revised to a proximal femoral locking plate, which also failed and eventually required revision to a total hip arthroplasty. Investigation of the implants post failure showed evidence of binding of the blade shaft in the barrel as a mechanism of failure in both cases. No DHS implants cut out in this series, although one patient was revised to a total hip arthroplasty for symptomatic segmental osteonecrosis.
Both implants performed well in a majority of cases. The higher incidence of failure in the DHHS group is concerning, despite the low numbers. The mechanism of failure of the DHHS implant left adequate bone stock for attempts at revision fixation.
评估动力螺旋髋系统（DHHS）螺旋刀片相对于动力髋螺钉（DHS）拉力螺钉的临床性能。
随机前瞻性研究。
一家二级创伤中心和一家三级创伤中心。
连续51例患者被纳入试验。纳入标准包括年龄超过50岁、AO/OTA 31A1或31A2骨折的患者。
手术由15名参与的社区骨科医生之一进行。患者被随机分为接受DHHS或DHS植入物治疗。在术后两周和六周进行随访，然后每六周随访一次，直至骨折愈合。
主要结局变量包括最终前后位X线片上植入物的滑动、穿出失败和植入物失败。
DHS组有24例患者，DHHS组有27例患者。两组在年龄、性别、美国麻醉医师协会（ASA）评分、骨折分类或术后即刻X线片上测量的复位质量方面无差异（p=0.28）。DHHS组的尖顶距为18.7 mm，DHS组为18.5 mm（p=0.40）。DHHS组刀片平均滑动7.4 mm，而DHS组拉力螺钉平均滑动7.7 mm（p=0.45）。DHHS组有2例因刀片穿入股骨头中心突出而失败，无明显内翻塌陷或向上移位。1例翻修为DHS并愈合，另1例翻修为股骨近端锁定钢板，但该钢板也失败，最终需要翻修为全髋关节置换术。对失败后的植入物进行检查发现，两例均有刀片柄在套筒内结合的迹象，这是失败的机制。本系列中没有DHS植入物穿出，尽管有1例患者因有症状的节段性骨坏死翻修为全髋关节置换术。
两种植入物在大多数情况下表现良好。尽管数量较少，但DHHS组较高的失败发生率令人担忧。DHHS植入物的失败机制为翻修固定尝试留下了足够的骨量。
