In a prospective randomized study of two groups of 65 patients each, we compared the acetabular component position when usingthe imageless navigation system compared to the freehand conventional technique for cementless total hip arthroplasty. The position of the component was determined postoperatively on computed tomographic scans of the pelvis. There was no significant difference for postoperative mean inclination (p=0.29), but a significant difference for mean postoperativ acetabular component anteversion (p=0.007), for mean deviation of the postoperative anteversion from the target position of 15°(p=0.02) and for the outliers regarding inclination (p=0.02) and anteversion (p<0.05) between the computer-assisted and the freehand-placement group.Material and Methods
Results
Patients were evaluated using the following means, clinical examination (AOFAS ankle-hindfood scale of H. Kitaoka), function score (Karlsson and Peterson), instability score (Good et al), radiological examination (according to Van Dijk et al), and dynamometric testing. All clinical and radiological tests were done on the treated and non treated sides (control group). We evaluated the results of our clinical testing as well as biplanar stress radiographs, using the TELOS device (15kp), with regards to talar shift and talar tilt. Dynamometric examination of both feet was performed and force descrepencies between the operated and non-operated sides was eveluated with regards to eversion force. Statistical testing were performed concerning short-, mid-, and long-term Results: (Kruskal-Wallis-tests and chi-squared-tests). All p-values <
0.0015625 were considered as statistically significant. The critical boundary results from the correction for multiplicity due to the number of tests (32 tests were performed, 0,05/32=0.0015625).
Most tenodesis techniques are showing the well known biomechanical disadvantages more or less. Our peroneusbrevis-shift technique (PBS-technique) offers a simple and safe surgical technique, a short learning curve and early weightbearing stability. It leads in 93% to excellent and good longterm results.