Tension and motion measurement for extended trochanteric osteotomy with different fixation methods

The Relationship Between Arthroplasty Surgeons' Experience Level and Optimal Cable Tensioning in the Fixation of Extended Trochanteric Osteotomy

Introduction

In this study, our aim was to examine the relationship between the arthroplasty surgeons’ experience level and their aptitude to adjust the cable tension to the value recommended by the manufacturer when asked to provide fixation with cables in artificial bones that underwent extended trochanteric osteotomy (ETO).

Materials and Methods

A custom-made cable tensioning device with a microvoltmeter was used to measure the tension values in Newtons (N). An ETO was performed on 4 artificial femur bones. Surgeons at various levels of experience attending the IX^th National Arthroplasty Congress were asked to fix the osteotomized fragment using 1.7-mm cables and the tensioning device. The participants’ demographic and experience data were investigated and recorded. The surgeons with different level of experience repeated the tensioning test 3 times and the average of these measurements were recorded.

Results

In 19 (35.2%) of the 54 participants, the force applied to the cable was found to be greater than the 490.33 N (50 kg) value recommended by the manufacturer. No statistically significant difference was determined between the surgeon’s years of experience, the number of cases, and the number of cables used and the tension applied over the recommended maximum value (P = .475, P = .312, and P = .691, respectively).

Conclusions

No significant relationship was found between the arthroplasty surgeon’s level of experience and the adjustment of the cable with the correct tension level. For this reason, we believe that the use of tensioning devices with calibrated tension gauges by orthopedic surgeons would help in reducing the number of complications that may occur due to the cable.

Extended trochanteric osteotomy: comparison of 3 modes of fixation: metallic wires, cables, plate, about a series of 157 cases

Introduction: The trans femoral osteotomy was initially described by Wagner in 1987 and the extended trochanteric osteotomy (ETO) was described by Younger et al. in 1995 and is considered to be the gold standard technique for removal of well-fixed femoral stems in revision total hip arthroplasty (THA). The purpose of this report is:

to compare the different types of fixation metallic wires, cables, metallic reinforcement plate (MRP) we have used in revision THA where an ETO was performed;

analyse the clinical and radiological outcomes of these devices at 1 year;

analyse the complication.

Materialand method: It is a retrospective continuous monocentric series of 157 patients where an ETO was performed. It was fixed by an MRP in 17 patients, cables in 43, metallic wires in 97. The main outcome was the consolidation of the osteotomized femoral flap (OFF). Secondary outcomes were Postel Merle d’Aubigne score and complications occurred at 1 year follow up. Qualitative variable was presented as percentage, quantitative variables as mean or median, standard deviation and range.

Result: 157 patients (73−46, 5% females) were included. Mean age at surgery was 66.7 year (sd = 10.63). Mean interval between index surgery and revision was 11.07 year (sd = 5.67). Causes for revision and bone defects were comparable. At 1 year OFF is healed without displacement in 82% with metallic wires, 70% with cables, 88% with MRP. Not significant.

Discussion: Fixation of the femoral flap is a technical issue in ETO. Metallic wires and cables are the most commonly used to secure the fixation. Fixation with a metallic plate is reported in a few number of articles and may be helpful specially when a fracture of the OFF occurred during surgery.

An in-vitro biomechanical study of different fixation techniques for the extended trochanteric osteotomy in revision THA

Background

The wire fixation and the cable grip fixation have been developed for the extended trochanteric osteotomy (ETO) in the revision of total hip arthroplasty (THA). Many studies reported the postoperative performance of the patients, but with little quantitative biomechanical comparison of the two fixation systems.

Methods

An in-vitro testing approach was designed to record the loosening between the femoral bed and the greater trochanter after fixations. Ten cadaveric femurs were chosen in this study. Each femur underwent the THA, revision by ETO and fixations. The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively. The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.

Results

In the vertical tension tests, the overall translation of the greater trochanter was observed 0.4 mm in the cable fixations and 7.0 mm in the wire fixations. In the lateral tension tests, the overall motion of the greater trochanter was 2.0 mm and 1.2° in the cable fixations, while it was 6.2 mm and 5.3° in the wire fixations. The result was significantly different between the two fixation systems.

Conclusions

The stability of the proximal femur after ETO using different fixations in the revision THA was investigated. The cable grip fixation was significantly more stable than the wire fixation.