Paper 25: Blood Flow Restriction Training Does Not Facilitate Faster Return To Sport Following ACL Reconstruction in Collegiate Athletes

Objectives: Blood Flow Restriction Training (BFRT) has been shown to be a safe and potentially effective therapeutic modality for postoperative rehabilitation, as it has been shown to improve quadriceps muscle strength in patients with weakness or atrophy related to knee pathology. However, there is a paucity of literature surrounding the implementation and effectiveness of BFRT in high-performance athletes following anterior cruciate ligament reconstruction (ACLR) and its effect on return to sport (RTS) times. The aims of this study were to 1) compare RTS times for Division I athletes using either BFRT or traditional physical therapy rehabilitation after ACLR, and 2) identify a possible postoperative time interval where BFRT has the most therapeutic benefit. Methods: A total of 104 student-athletes who underwent primary ACLR while participating in Division I athletics at our institution were included in the study. Each athlete underwent a standardized postoperative rehabilitation protocol using BFRT or the standardized regimen alone. Our primary outcome measure was RTS times, measured from the date of surgery to the date of full participation clearance by the supervising orthopaedic surgeon and physical therapist. RTS times were then compared for BFRT and non-BFRT groups. Secondary outcome measure was handheld dynamometry (HHD) strength testing of quadriceps at various time points postoperatively, measured as a percentage compared to the unaffected extremity. Results: In comparing the two cohorts, the age in years at date of surgery was 18.59 ± 1.10 for the BFRT group and 19.45 ± 1.30 for the non-BFRT group, [p= 0.011 (Table 1)]. Mean RTS time was 409 ± 134 days from surgery for the BFRT group and 332 ± 100 days for non-BFRT, (p=0.047). The BFRT group had a gender distribution of 55% male, and 45% female. For the BFRT Group, mean quadriceps HHD increased by 0.67 percentage points for every 1 week of rehabilitation [95% CI (0.53, 0.81)]. Average absolute change in HHD per four-week interval was then calculated with respect to initial HHD measures taken during weeks 5-8 postoperatively, the first data points available for our participants. Weeks 13-16 had the first significant change from baseline, with an absolute HHD difference of 10.21, (p=0.017). Weeks 17-20 had an average decrease in HHD gained compared to the previous interval, with a difference of 8.93 from baseline (p=0.055). All subsequent intervals continued to have significant HHD gains relative to the baseline value with a steady upward trend over time. Conclusions: Our data leads us to conclude that in elite, NCAA Division I athletes there was no improvement in RTS outcomes with BFRT compared to standardized physical therapy alone after undergoing ACLR. Additionally, there is no clear time period studied in our patient population where BFRT appears to have the most therapeutic benefit. There is an apparent need for additional prospective studies to establish a protocol of progressive load management while utilizing BFRT in order to better understand and maximize the benefit of this relatively new therapeutic modality. [Table: see text][Figure: see text]