Budnar Vijaya M, Bannister Gordon C
Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK.
Hip Int. 2012 May-Jun;22(3):302-6. doi: 10.5301/HIP.2012.9243.
Poor proximal femoral pressures during a cemented primary hip replacement may compromise proximal fixation and cause early aseptic loosening. Occlusion of the calcar, during stem insertion, achieves a uniform and sustained rise in the proximal intra-medullary pressure, which should enhance cement penetration into bone and improve long-term survival of the prosthesis.
54 Exeter stems were cemented into femoral moulds prepared from plaster of Paris. Pressure transducers were connected to the proximal, middle and distal zones of the mould. After cement insertion, stems were implanted with occlusion of the calcar by either nothing, a thumb placed medially or an Exeter horse-collar. 18 stems each were inserted into Palacos-R at 3½-4 minutes and 4-4½ minutes after mixing and Simplex-P 6-6½ minutes after mixing and the intra-medullary pressures were measured. Data were subjected to regression analysis using SPSS.
Proximal and distal intra-medullary pressures were significantly higher (P < 0.01-0.001) with proximal occlusion in all cements. The highest pressures were achieved with Palacos-R at 4-4½ minutes after mixing, with proximal thumb occlusion. Stem insertion into Palacos-R at 3½-4 min. or 4-4½ min. after mixing, gave higher pressures than into Simplex-P regardless of the method of occlusion. With Simplex-P, there was a trend to higher proximal intra-medullary pressures with the horse-collar.
Occluding the calcar during stem insertion into cement achieves and sustains high intra-medullary pressures in both the proximal and distal femur. The highest pressures are obtained with stem insertion into Palacos-R at 4-4½ minutes after mixing, with proximal thumb occlusion. A horse-collar achieves slightly higher pressures with Simplex-P.
在初次骨水泥型髋关节置换术中，股骨近端压力不佳可能会影响近端固定并导致早期无菌性松动。在柄插入过程中封闭股骨距可使近端髓腔内压力均匀且持续升高，这应能增强骨水泥向骨内的渗透并提高假体的长期生存率。
将54个埃克塞特柄骨水泥固定于由熟石膏制成的股骨模型中。压力传感器连接至模型的近端、中部和远端区域。骨水泥插入后，通过不做任何处理、在内侧放置拇指或使用埃克塞特马领圈封闭股骨距的方式植入柄。每种骨水泥各有18个柄，分别在混合后3.5 - 4分钟和4 - 4.5分钟插入Palacos - R骨水泥中，以及在混合后6 - 6.5分钟插入Simplex - P骨水泥中，并测量髓腔内压力。使用SPSS对数据进行回归分析。
在所有骨水泥中，近端封闭时近端和远端髓腔内压力均显著更高（P < ０.０１ - ０.００１）。混合后4 - 4.5分钟使用Palacos - R骨水泥且近端拇指封闭时压力最高。无论采用何种封闭方式，在混合后3.5 - 4分钟或4 - 4.5分钟将柄插入Palacos - R骨水泥中时的压力均高于插入Simplex - P骨水泥中时的压力。对于Simplex - P骨水泥，使用马领圈时有近端髓腔内压力更高的趋势。
在将柄插入骨水泥过程中封闭股骨距可使股骨近端和远端髓腔内压力升高并维持在高位。混合后4 - 4.5分钟将柄插入Palacos - R骨水泥中且近端拇指封闭时压力最高。使用Simplex - P骨水泥时，马领圈可使压力略高。
