Force transmission in offset broach handles used for hip replacement: comparison of three different designs.

In minimally invasive hip arthroplasty double offset broach handles are used, to facilitate the preparation of the femoral canal. The aim of this study was to quantify the differences in force and impulse transmission between two double offset broach handles and a single offset broach handle. Two double offset broach handles (A European version, B American version) were compared to a single offset broach handle. A surgical hammer was used to give a variable impact to the head of the broach handle. Thirty measurements for each of five falling heights were recorded for each broach handle. The force measured by a load cell connected to the broaches was used to obtain the maximum force peak and to calculate the impaction impulse. Normal data distribution was assumed and analysis of variances was performed. Results have demonstrated that the highest values of the force peak and force impulse were found in the single offset broach handle. Broach handle A had higher impulse values and lower maximum force values compared to broach handle B. The lateral lever arm has a measurable effect on the force transmission. In double offset broach handles less energy is transmitted to the tip. Surgeons have to be aware of the differences between the broach handles when using them intraoperatively.