A prospective randomised study was carried out to compare two methods of pain control following arthroscopically assisted ACL reconstruction.

Twenty patients each were randomly recruited to receive either femoral nerve block with 0.5% Bupivicaine or an intra-articular injection with the same. Both groups were prescribed Diclofenac regularly and Coproxamol as required. Visual analogue scores (VAS) were used to assess pain levels preoperatively, four hours postoperatively and on the morning after. The duration between surgery and the first dose of PRN analgesia was recorded, along with the total quantity of analgesia required before discharge. Patients with associated PCL or collateral ligament injuries were excluded beforehand.

Both groups were evenly matched for age (t-test p< 0.05). Tourniquet time did not differ significantly between the groups (t-test p:0.24). The VAS pain levels were not significantly different at four hours and the first morning postoperatively in both groups. Femoral block (Ave VAS: 21 & 25) did not confer a significant advantage (t-test p: 0.69, 0.7) over intra-articular injections of Bupivicaine (Ave VAS: 25 & 22). The total quantity of Coproxamol consumed did not vary significantly (p=0.99). There was no correlation between tourniquet time and postoperative pain (r=0.19, 0.08). All but one patient was discharged home on the first postoperative morning.

Our study demonstrates that pain levels can be sufficiently controlled by intra-articular infiltration of Bupivicaine coupled with oral analgesia. The level of pain relief achieved could allow this procedure to be increasingly performed in a day surgery setting without the need for femoral block thereby allowing for quicker mobilisation.