Summary

Compared to a traditional rehabilitation program, early use of blood flow restriction training coupled with low intensity exercises improves knee extension strength, range of motion, and pain in the acute post-operative phase (weeks 0-12) following ACL reconstruction.

Abstract

Background

Blood flow restriction therapy (BFRT) has been proposed as a way to enhance rehabilitation following anterior cruciate ligament reconstruction (ACLR). However, a paucity of data exists to support the use of BFRT in clinical practice. The purpose of this study is to determine if early application of BFRT, used with low-load (LL) therapy exercises, increases quadriceps strength, and functional outcomes following ACLR compared to a traditional rehabilitation protocol without BFRT.

Methods

Forty-five patients undergoing ACLR were randomized to receive either: (1) a traditional rehabilitation program (n=23), or (2) a modified program using BFRT with LL (20-50% of 1-repetition maximum) exercises (n=22). Two patients crossed over from the control to BFRT groups at postoperative weeks 2 and 4, respectively. An as-treated analysis was performed for biweekly measurements in the early postoperative period of range of motion (ROM), thigh circumference, and terminal knee extension (TKE) strength. Circumference and TKE strength were analyzed as a percentage of the contralateral side. VAS and IKDC scores were assessed preoperatively and during the first 12 weeks postoperatively.

Results

Compared to the control group, the BFRT patients demonstrated significantly greater TKE strength at week 8 (72.9% vs. 79.4%, p = 0.043) and week 12 (73.0% vs. 85.5%, p = 0.030) , as well as greater overall change in TKE strength from week 3 to 12 (9.2% vs 24.2%, p = 0.011). The BFRT group reported significantly lower VAS values at week 12 (1.2 vs. 0.3, p = 0.013) and significantly higher IKDC scores at week 12 (52.9 vs 61.8, p = 0.027). The BFRT group also reported significantly greater flexion than control for week 4 (91.8 vs 102.0, p = 0.025), week 6 (112.7 vs 121.1, p = 0.036), and week 12 (130.5 vs 137.2, p = 0.028).

Conclusions

In comparison to a traditional rehabilitation protocol following ACLR, BFRT used in conjunction with LL exercises during the early postoperative period was associated with significantly lower VAS scores as well as significantly greater quadriceps strength and knee flexion. These results suggest that BFRT may help resist muscle atrophy and/or promote muscle hypertrophy during rehabilitation after ACLR, though future studies are needed to assess long-term outcomes.