Arthroscopic single-stranded semitendinosus tendon- versus PDS-augmentation of reinserted acute femoral anterior cruciate ligament tears: 7 year follow-up study

This study reviews the long-term results of acute complete femoral tears or combined femoral (2/3 of the ligament diameter) /interstitial tears of the anterior cruciate ligament (ACL) that were reinserted. Out of 27 patients, 11 were treated with reinsertion plus augmentation with single-stranded semitendinosus tendon, 16 patients had a reinsertion and augmentation with a double-stranded PDS-band. Operation was carried out 10 (2-42) days after trauma. A brace was applied for 12 weeks, full weight bearing was allowed after 6 weeks according to our standard rehabilitation protocol. Twenty two patients (81%) could be reevaluated after a mean follow-up time of 7 years 1 month (range 3 years 8 months -11 years 5 months). No statistically significant difference was found between both techniques concerning patient's satisfaction and subjective evaluation of knee function, OAK-scores (semitendinosus-augmentation: 96 point, SD 2.0 PDS-augmentation: 94 points, SD 5.1) and IKDC-scores. Only in the PDS-augmentation group a statistically significant decrease was found in the level of activity in sports (P=0.046). At follow-up, radiological evaluation of the anterior drawer test was performed. In the group of patients who had undergone semitendinosus augmentation (n=9), anterior displacement of the tibia (determined radiologically using the TELOS-device) of 0-2 mm was found in five patients, displacement of 3-5 mm was seen in three cases and displacement of 6-10 mm in one patient (average 2.7 mm). Patients treated with PDS-augmentation (n=13) showed anterior tibial displacement of 0-2 mm in five cases, 3-5 mm in five cases, and 6-10 mm in two knees (average 3.6 mm). One patient of this group underwent ACL-reconstruction 6 years after reinsertion because of recurrent instability. At follow up, flexion was limited to less than 135 degrees in three patients (12.5%). One patient who had undergone semitendinosus augmentation and three patients from the PDS-augmentation group developed a cyclops syndrome and intraarticular adhaesions that were treated arthroscopically 6 to 18 month after reinsertion surgery. A tendency towards a higher rate of limitation in range of motion was found for the PDS augmentation group. The reinsertion of a femoral torn ACL plus augmentation with a single strand of semitendinosus tendon or a PDS-band leads to acceptable results, an agressive rehabilitation protocol may help to decrease the rate of limitation of flexion.