Serial dilation reduces graft slippage compared to extraction drilling in anterior cruciate ligament reconstruction: a randomized controlled trial using radiostereometric analysis

PURPOSE: This study tested the hypothesis that serial dilation of the tibial tunnel could provide a stronger anchorage of the graft-fixation-device complex compared to traditional extraction drilling.

METHODS: Forty patients (22 men and 18 women) undergoing ACL reconstruction were randomized to either extraction drilling (group ED) or compaction by serial dilation (group SD) of the tibial tunnel. Tantalum beads were placed in the tibia, femur, and in the hamstring graft. Radiostereometric analysis (RSA) was performed postoperatively and again after 6, 12, and 24 weeks. Migration of graft in the bone tunnels as well as knee laxity was assessed using RSA and a TELOS stress device.

RESULTS: Six patients (three men and three women) were excluded during follow-up, which resulted in 17 patients in group ED [median age 30 years (range 20-50)] and 17 patients in group SD [median age 32 years (range 20-49)]. The mean migration of the graft in the tibial bone canal after 3 months was 1.3 (SD 0.6) mm in group ED and 0.8 (SD 0.5) mm in group SD (P = 0.02). The overall knee laxity after 3 months was 13.0 (SD 4.0) mm in group ED and 10.9 (SD 3.1) mm in group SD.

CONCLUSION: This study found less slippage of the hamstring graft in the tibial bone canal in the serial dilated group compared to the extraction drilling group. The clinical relevance of the difference is unknown. No difference in stress radiographic knee laxity was found between the two groups.