Pain relieve without impairing muscle function after local infiltration anaesthesia in primary knee arthroplasty: a prospective randomized study

Purpose

Purpose of the current study was to compare early effectiveness of pain relieve of 3 in 1 regional pain catheter to local infiltration anesthesia (LIA) in primary total knee arthroplasty (TKA). Secondary endpoint was quadriceps muscle strength after both procedures.

Material and methods

A single-center, prospective, randomized controlled trial was performed. Patients eligible to TKA were either randomized into group 3 in 1 regional pain catheter (C), or group local infiltration anesthesia (L). Pain relieve was assessed by visual analogue scale (VAS) at rest and under physical activity (PA) prior to surgery (t0) and at days one through six. In addition, quadriceps muscle strength ( = straight leg raise) was tested according to the Manual Muscle Testing Scale. Functional outcome was measured using the Oxford Knee Score (OKS) preoperatively and 6 months postoperatively.

Results

121 patients were included in the study. 59 (48.8%) patients were allocated to group C, 62 (51.2%) patients to Group L. No differences concerning pain level evaluated by VAS could be detected between the groups at any time. Comparing straight leg raise test group L was significantly superior over the complete postoperative period (p < 0.03). The mean OKS decreased significantly (p < 0.001) from preoperatively 34.2 ± 7.5 points to 16.9 ± 6.0 points at the six months final follow-up. Regarding OKS there were no intergroup differences at the final follow-up at 6 months postoperative.

Conclusion

There is no significant difference in pain relieve comparing LIA to 3 in 1 catheter in perioperative pain management in TKA. The advantage of LIA is unimpaired quadriceps muscle function in the short-term follow-up.