Aims: Serial dilation of the walls of the bone tunnel has been advocated to provide more dense bone-tunnel walls and optimal conditions for rigid fixation in anterior cruciate ligament (ACL) reconstruction with soft tissue grafts. The aim of this study was to compare the initial fixation strength obtained using serial dilation versus conventional extraction drilling in ACL reconstruction. Methods: Initial strength of doubled anterior tibialis tendon grafts fixed with bioabsorbable interference screw was assessed in 21 pairs of human cadaver tibiae. Bone tunnels were created with either serial dilation or conventional extraction drilling (cannulated drill bits). The specimens were subjected to a cyclic-loading test (1500 loading cycles between 50 and 200 N at 0.5 Hz frequency). The specimens surviving the cyclic-loading test were loaded to failure at a rate of 1.0 m/min (single-cycle load-to-failure test). Results: During the cyclic-loading test, no significant stiffness or displacement differences were observed between the two bone-tunnel techniques. Three specimens failed in the serial-dilation group, while there were six failures in the extraction-drilling group. In the subsequent single-cycle load-to-failure test, the average yield load was 473 ± 110 N for the serial-dilation group and 480 ± 115 N for the extraction-drilling group (P=0.97). No significant difference between the two bone-tunnel techniques was found with regard to stiffness nor mode of failure. Conclusions: Serial dilation of the bone-tunnel walls does not increase the initial fixation strength of soft tissue grafts in ACL reconstruction.

We compared the strength of fixation of a biodegradable screw with that of two metal screws in a bone-patellar-tendon-bone (BPTB) graft in the bovine knee. We used 33 fresh BPTB specimens with a circular tibial bone plug of 9 mm in diameter which were anchored in a tibial metaphyseal bone tunnel with either an interference screw (n = 11), an AO cancellous screw (n = 11) or a fibrillated, self-reinforced biodegradable poly-L-lactide screw (n = 11). The mean force to failure (+/- SD) in the three groups was 1358 +/- 348 N, 1081 +/- 331 N and 1211 +/- 362 N, respectively. There was no significant difference in the groups with regard to the linear load or the elastic moduli of the fixation. We conclude that the biodegradable screw is as good as either of the two metal screws in the fixation of a BPTB graft in the bovine knee and can be recommended for ACL reconstruction using this type of graft.

The effect of tenotomy and of immobilisation in lengthened and shortened positions on the intramuscular connective tissue of the calf muscles of the rat was studied morphometrically and with a scanning electron microscope. Both tenotomy and immobilisation produced a marked increase in both the endomysial and the perimysial collagen networks, with a simultaneous decrease in intramuscular capillary density. The increase in connective tissue volume was more pronounced and occurred more rapidly in the soleus, which consists mainly of type I, slow-twitch fibres than in the gastrocnemius, which is mainly of type II, fast-twitch fibres. The relative volume of connective tissue increased in parallel with the duration of immobilisation or after tenotomy. There was slightly more increase after immobilisation in a shortened rather than in a lengthened position.

We aimed to determine the distribution of the ABO and Rh blood groups in 832 patients with a tendon rupture. Among these, the frequency of blood group O (52.8%) was significantly higher than in the general population of Hungary (31.1%) and the frequency of group A was significantly lower. Of the 83 cases of multiple ruptures or re-rupture, 57 patients (68.7%) had group O blood. The dominance of group O was found for all sites of tendon rupture, but there was no significant association with the Rh groups. Individuals with blood group O appear to have an increased risk of tendon rupture.

We have reviewed 32 patients who sustained a substantial knee ligament injury during adolescence when their knee epiphyses were open. They were all treated non-operatively and re-examined and evaluated in detail after an average of eight years. There were 25 Grade II partial tears and seven Grade III complete tears. After Grade II injuries the functional results were excellent or good, though static instability had not improved from the initial post-traumatic examination. The long-term results of Grade III injuries were poor, because of chronic functional instability, with continuous symptoms and some post-traumatic osteoarthritis. The results of non-operative treatment for Grade III ligament injuries were not acceptable.