Laffargue P, Pinoit Y, Tabutin J, Giraud F, Puget J, Migaud H
Service d'Orthopédie C, Hôpital Salengro, CHRU de Lille, 59037 Lille Cedex.
Rev Chir Orthop Reparatrice Appar Mot. 2006 Jun;92(4):316-25. doi: 10.1016/s0035-1040(06)75761-0.
Most navigation systems for computer-assisted total hip arthroplasty (THA) require prior computed tomography (CT) or acquisition of multiple bone landmarks on the pelvis. In order to avoid these problems, we developed a computer-assisted navigation system without CT based on a kinematic approach to the hip joint. The principle is to orient the cup in relation to the cone describing the hip joint range of motion. The purpose of this work was to analyze preliminary results.
Eighteen primary THA were implanted with the system (16 women, two men, mean age 68 +/- 7.8 years, age range 54-83 years, 18 degenerative hip disease). Two optoelectronic captors were fixed percutaneously on the pelvis and the distal femur. The acetabulum was prepared first followed by the femur using reamers and broaches of increasing size. The last broach placed in the femur was equipped with a large head adapted to the newly prepared acetabulum. The range of hip motion was recorded to determine the maximal range of motion cone. The acetabular cup was thus positioned in order the prosthesis range of motion included entirely the maximal range of motion of the hip joint.
One patient fell three weeks after implantation causing posterior dislocation; there was no recurrence. The Postel-Merle-d'Aubligné score improved from 8 +/- 2.9 (range 3-12) preoperatively to 17 +/- 0.8 (range 16-18) at last follow-up. None of the patients complained about the captor insertion and there were no cases of hematoma or fracture. Operative time was 35-40 minutes longer for the first four cases and was progressively reduced 15-20 minutes for the last four cases. Mean leg length discrepancy was 5.6 +/- 7.5 mm (range 0-25) before implantation and 0.6 +/- 3 mm (range -5 to 10 mm) at last follow-up. CT-scan measurements revealed a mean anteversion of the femoral implant of 18.2 +/- 8.5 degrees (range 0-31). Anatomic anteversion of the cup (measured from the pelvis landmark and thus independently of the position of the pelvis) was 24.7 +/- 8.8 degrees (range 12-40). The sum of the femoral and anatomic acetabular anteversions was 43 +/- 13.1 degrees (range 22-71). Anteversions were 16 degrees for the cup and 16 degrees for the stem for the one case of dislocation.
This method can be used in routine without lengthening operative time significantly. It safely controls leg length and helps position the cup. This study demonstrated that there is no ideal position for the cup which can be used for all patients. Because of the wide range of inclination and anteversion figures, half of the cases were outside the safety zone recommended by Lewinnek.
大多数计算机辅助全髋关节置换术（THA）的导航系统需要事先进行计算机断层扫描（CT）或获取骨盆上的多个骨标志点。为避免这些问题，我们基于髋关节的运动学方法开发了一种无需CT的计算机辅助导航系统。其原理是根据描述髋关节运动范围的圆锥体来确定髋臼杯的方向。本研究旨在分析初步结果。
18例初次全髋关节置换术患者使用该系统进行植入手术（16名女性，2名男性，平均年龄68±7.8岁，年龄范围54 - 83岁，均为退行性髋关节疾病）。在骨盆和股骨远端经皮固定两个光电传感器。首先使用尺寸逐渐增大的扩孔钻和拉刀准备髋臼，随后准备股骨。最后置于股骨中的拉刀配备有一个与新准备的髋臼相适配的大头。记录髋关节的运动范围以确定最大运动范围圆锥体。髋臼杯的放置应使假体的运动范围完全包含髋关节的最大运动范围。
1例患者在植入后三周摔倒导致后脱位，未再复发。Postel-Merle-d'Aubligné评分从术前的8±2.9（范围3 - 12）提高到末次随访时的17±0.8（范围16 - 18）。所有患者均未对传感器植入提出抱怨，也无血肿或骨折病例。前4例手术时间比后4例长35 - 40分钟，后4例手术时间逐渐减少15 - 20分钟。植入前平均下肢长度差异为5.6±7.5毫米（范围0 - 25），末次随访时为0.6±3毫米（范围 - 5至10毫米）。CT扫描测量显示股骨假体平均前倾角为18.2±8.5度（范围0 - 31）。髋臼杯的解剖学前倾角（从骨盆标志点测量，因此与骨盆位置无关）为24.7±8.8度（范围12 - 40）。股骨和髋臼解剖学前倾角之和为43±13.1度（范围22 - 71）。脱位的1例患者中，髋臼杯前倾角为16度，股骨柄前倾角为16度。
该方法可在不显著延长手术时间的情况下用于常规手术。它能安全地控制下肢长度并有助于髋臼杯的定位。本研究表明，不存在适用于所有患者的髋臼杯理想位置。由于倾斜度和前倾角数值范围较宽，一半的病例超出了Lewinnek推荐的安全区。
