On-table decision-making in intracapsular hip fracture surgery: mid-term results of a pilot study.

INTRODUCTION: At the present time, it is generally recommended to use hip replacement in dislocated fractures to avoid failure after internal fixation. A problem is that previous research has demonstrated that observers have problems in discriminating between dislocated and undislocated fractures. A possible solution to this problem would be to use arthroplasty in the majority of the cases. However, this also means that many fractures with the potential for uneventful healing would be replaced. MATERIALS AND METHODS: In the current investigation, the mid-term outcome was recorded for patients with intracapsular hip fractures who were treated with either internal fixation or arthroplasty. A novel treatment algorithm was employed. After careful exclusion of cases with known risk factors for failure after internal fixation, a technique called on-table decision was used to identify suitable patients for internal fixation. RESULTS: A total of 72 patients with intracapsular hip fractures were studied with a median follow-up time of 12 months (IQR 8-15.25 months). Nineteen (19) patients (26 %) were excluded in the selection process, leaving 53 (74 %) for on-table decision-making. Thirty patients (42 %) were identified as suitable for internal fixation and gave anatomically stable closed reductions. Two of these patients (7 %) exhibited non-unions and one (3 %) avascular necrosis. CONCLUSIONS: The mid-term outcome after internal fixation is promising. The careful selection process may be helpful in identifying fracture patterns for which internal fixation may be considered as a safe and less invasive alternative to hip arthroplasty.

A novel electromagnetic navigation tool for acetabular surgery.

BACKGROUND: Acetabular fracture surgery is demanding and screw placement along narrow bony corridors remains challenging. It necessitates x-ray radiation for fluoroscopically assisted screw insertion. The purpose of this cadaver study was to evaluate the feasibility, accuracy and operation time of a novel electromagnetic navigation system for screw insertion along predefined acetabular corridors. METHODS: A controlled laboratory study with a total of 24 electromagnetically navigated screw insertions was performed on 8 cadaveric acetabula. 3 peri-acetabular bony corridors (QSS, Quadrilateral Surface Screw; IAS, Infra-Acetabular Screw; PCS, Posterior Column Screw) were defined and screws were placed in a defined order without fluoroscopy. Operation time was documented. Postoperative CT scans were performed to analyse accuracy of screw placement. RESULTS: Mean cadaver age was 70.4 ± 11.7. Successful screw placement was accomplished in 22 out of 24 (91.7%) cases. The overall mean time for all 3 acetabular screws was 576.6 ± 75.9s. All 3 complications occurred during the placement of the IAS due to an impassable narrow bony corridor. QSS mean length was 50 ± 5mm, IAS mean length was 85 ± 10mm and PCS mean length was 120 ± 5mm. CONCLUSION: In this cadaver study the novel electromagnetic navigation system was feasible to allow accurate screw placement without fluoroscopy in defined narrow peri-acetabular bony corridors.

Computer-assisted surgery and intraoperative three-dimensional imaging for screw placement in different pelvic regions.

BACKGROUND: The purpose of this study was to assess the feasibility and accuracy of computer-assisted surgery (CAS) for screw placement in different pelvic regions using intraoperative three-dimensional (3D) imaging and to evaluate the influence of surgeons' experience with such a system on procedure time, radiation time, radiation dose, and misplacement rate. METHODS: Experimental study in a human cadaveric model (n=5) for percutaneous screw placement in the anterior column of the acetabulum, the posterior pelvic ring (S1, S2), and the superior pubic ramus via 3D fluoroscopic navigated procedure. Accuracy of screw placement was assessed by 3D image intensifier, including the reconstruction of multiplanar images and by computer tomography (CT) scan. Influence of surgeons' experience was assessed by direct comparison of a low- and high-volume surgeon using the same technical setting. RESULTS: In 100% of all procedures, intraoperative Iso-C3D image analysis was sufficient to confirm a correct screw placement. The postoperative CT scan revealed no further screw misplacement. However, for a correct supraacetabular screw placement, the intraoperative 3D scan was essential. In this group, the 3D scan showed screw misplacement in three cases. Procedure time for all indications and screw failure rate were significantly lower for the higher experienced surgeon. CONCLUSION: The 3D fluoroscopic navigated procedure in pelvic surgery seems to be a useful tool for all surgeons and especially for less experienced ones. Furthermore, the intraoperative reconstruction of multiplanar 3D images allows a secure control of implant positioning.