The objective of the study was to verify a positive effect of an additional oblique cancellous screw on the primary rotational stability of complete and incomplete high tibial closed-wedge osteotomies (8°) in ovine tibiae. Of 51 specimen 48 were employed for final results. The osteotomy site was stabilized with L-shaped plates (Allopro, Sulzer Orthopedics GmbH, Freiburg, Germany). The specimen were subdivided in 4 groups: complete (1/2) and incomplete (4/5 of the mediolateral tibial diameter in height of the horizontal sawing-jig) (3/4) osteotomies each with (1/3)) and without (2/4) an additional oblique cancellous screw. Constant axial load of 200 Newton and rotational velocity of 0,496°/sec. was applied during testing. 8 ovine specimen were tested without osteotomy or rigid fixation as a control group (5). Statistical significance (p<
0,05) was determined via the nonparametric Mann-Whitney U-test. The results were charted with SPSS (version 11.0). Correlation between objective measurement parameters and primary rotational stability of the specimen was displayed according to Pearson. The primary rotational stabilty in group 1 (intact medial cortical bone, incomplete osteotomy with additional oblique cancellous screw) was significantly higher than in groups 2, 3 and 4. In this group the resulting torsional moments in the initial part of the charted graphs were even higher than in the control group. Group 2 (incomplete osteotomy without a oblique cancellous screw) showed a significantly higher primary rotational stability compared to the groups with complete osteotomy (group 3/4). Between the groups with complete osteotomy (3/4) no significant differences in rotational stability occured. No significant correlation could be found between the objective measurement parameters of the specimen (length, weight, maximal width of the tibial plateau) and the primary rotational stability of the rigidly fixated ovine tibiae. This biomechanical in-vitro assessment showed that an intact medial cortical bone bridge has a statistically significant impact on the primary rotational stability of lateral closed-wedge osteotomies in proximal tibiae. An oblique cancellous screw through the osteotomy gap has an additional effect concerning rotational stability. In case of complete osteotomy of the proximal tibiae or due to inadequate operative technique the stabilizing effect of the medial cortical bone bridge gets lost. This results in a deterioration of rotational stability at the osteotomy site and in a sufficicantly rigid fixation is no longer guaranteed. In this case an additionally inserted oblique cancellous bone screw leads to higher resistance against rotational forces. A rigid osteosynthetic stabilization of corrective osteotomies in proximal tibiae seems a condition precedent to obtain the desired correction angle.
Posttraumatic shoulder instability is a common problem in the field of sports medicine. Especially overhead athletes need intact stabilisers to meet the functional requirements. Open procedures often result in limitations of movement postoperatively. Arthroscopic techniques offer potential advantages such as better range of motion and shorter rehabilitation times. Between September 1996 and October 2000 159 arthroscopic shoulder stabilisations were performed with FASTak® anchors. The mean follow up was 24.9 months (12–50). Rowe score and a visual analogue scale were used to measure patient satisfaction. 72 patients (m=57, f=15)with a mean age of 27.6 years (17–65) were included and clinically examined. The Rowe score increased to 83.1 after primary stabilisation and 68.1 after revision procedures. The visual analogue score demonstrated overall patient satisfaction. 89.1% (n=64) of the patients could return to sports with 68,4% (n=49) being able to return to their previous sports activity level. Overhead athletes returned to sports in 89.4% of cases and 63.3% to their pre-injury level. In the non-overhead athletes 86% returned to sports with 60% to their pre-injury level. This study demonstrates that arthroscopic shoulder stabilisation with FASTak® anchors may be offered to the athlete regardless of the sports activity. It allows return to sports in a high percentage and does offer the potential advantages of a faster return to the previous activity level, better range of motion and less postoperative pain. Disadvantages of the technique is a long learning curve and should therefore only be performed by dedicated and experienced shoulder surgeons.