Introduction: Chronic anterolateral instabilitiy of the ankle joint is a combination of mechanical and functional instability. Various surgical procedures are well known. Many of them are peroneus brevis tenodesis techniques.

We demonstrate our modified surgical procedure (Peroneus-brevis-shift technique) as well as report results from 2 to 17 years post operatively, as short-, mid-, and long-term results.

OP-technique: The intact peronaeus brevis tendon is shifted and sutured fronto-lateral of the malleolus lateralis in neutral polsition of the foot. Postoperatively full weight bearing without a blaster is allowed, a splint for 3 weeks is recommended.

Patients and Methods: From 11/86 to 12/04 91 patients (95 feet) were treated with our modified peroneus brevis tenodesis augmentation. Preoperatively all patients were treated conservatively without success. Following surgical treatment all patients under went a standardised post operative treatment protocol. In this retrospective study 73 patients (81,1%) resp. 77 feet (81%) with a meantime follow up of 9.3 ± 4.7yrs were available for evaluation.

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).

Results: Short- (2–5yrs), mid- (6–10yrs) and long-term (11–17yrs) results showed no statistically significant differences in any clinical or radiological testing between the treated and control side.

Discussion: In many cases of chronic lateral instability of the ankle also a strain of the lateral talocalcaneal joint is seen.

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.