Tunnel enlargement after AC reconstruction with a hamstring autograft has been noticed mainly the first 3–6 months postoperatively. Its etiology involves biomechanical and biological factors. The aggressive rehabilitation program is another etiological factor. The aim of this study is to investigate the tunnel enlargement after ACL reconstruction with a Hamstring autograft by the aid of CT-scan.

We investigate the tunnel diameter in a series of 25 consecutive patients who operated with a Hamstring autograft 3 months postoperatively. The mean age of the patients was 23.6 years old (18–35). The same femoral fixation system (XObutton) and the same tibial fixation system (bioabsorbable screw) were used in all the patients. All the follow the same rehabilitation program, partial weight bearing from the 1st postoperative day, brace for 3–5 weeks and return to sports activities in 6 months.

In 2 patients a meniscal suture was performed and in 3 patients a partial meniscectomy was performed. All patients had excellent clinical result which was demonstrated by the physical examination and by the KT-1000 results. Statistical analysis was performed with the SPSS system. We noticed a tunnel enlargement in the majority of the patients, but this was not statistical significant (P< 0.01).

Tunnel enlargement after ACL reconstruction with a hamstring autograft has been noticed the first postoperative months, especially with the use of suspensor fixation systems. However in our study the tunnel enlargement is not correlated with a poor clinical outcome.