Stability of femoral neck fracture: Roentgen stereophotogrammetry of 29 hook-pinned fractures

Abstract

The stability of hook-pin fixation during weight bearing was studied in 29 femoral neck fractures using roentgen stereophotogrammetric analysis. Twenty-three fractures became stable within 1 to 9 months, whereas redisplacement or continuing movement of the fracture occurred in 6 cases. Displaced fractures shortened about 7 mm more than undisplaced ones before healing. The rotations of the femoral heads were greatest in the forward/backward direction, followed by varus-valgus tilting in both fracture groups. Rotation about the longitudinal axis was recorded in the displaced fractures, mainly as a retroversion, whereas no rotation occurred about this axis in the undisplaced fractures. Healing after 6 months, intermediate fracture fragments, and a decreased Pauwels' angle seemed to imply increased fracture compression or rotatory instability. Fractures that subsequently developed healing complications displayed an increased distal displacement of the femoral head during the first postoperative month.

Good stability but high periprosthetic bone mineral loss and late-occurring periprosthetic fractures with use of uncemented tapered femoral stems in patients with a femoral neck fracture

“…We used RSA to evaluate the fixation of the stem, and although RSA has been used to study the healing of FNFs after internal fixation (Ragnarsson and Kärrholm 1991), only 3 other studies using RSA have been published on the subject of hip arthroplasty in this patient group. The first involved the 2-year results of the current study and the other 2 studies dealt with the subject of cartilage wear and implant stability following hemiarthroplasty (Figved et al 2012, Schewelov et al 2012).…”

The accuracy of measurements of femoral neck fractures

“…In comparison to the RSA values for the displacements along the transverse (X) axis, the MLD values were on an average underestimated by 1.2 mm and displayed a high variability, especially in relation to the usually small translations occurring along the transverse axis during fracture healing (Ragnarsson 1991). This inaccuracy might be explained by the sensitivity of the MLD to intemal/extemal hip rotation and by the oval shape of the femoral shaft (Bell and Brand 1989).…”

“…Medial-lateral, proximaldistal, and anterior-posterior translations of the center of the femoral head were measured (Ragnarsson et al 1989(Ragnarsson et al , 1991; and for the purpose of the present study, the error of RSA was disregarded (Ragnarsson et al 1989).…”

Differentially Loaded Radiostereometric Analysis to Monitor Fracture Stiffness: A Feasibility Study

“…Clinical studies have used RSA to assess the position of specific fragments during the time of healing in ankle fractures [1][2][3][4][5], trochanteric fractures [17,29,30,[35][36][37][38][39], high tibial osteotomies [33], tibial plateau fractures [44], and radial fractures [26,27]. For each of these studies, single RSA examinations were performed at prospective followups and interfragmentary displacement with time was measured.…”