Quadriceps atrophy and weakness can persist for years after anterior cruciate ligament reconstruction (ACLR). We evaluated the effectiveness of a home-based blood flow restriction (BFR) exercise program to increase quadriceps size and strength several years after ACLR. Nine adults with ACLR (5±2 yrs post-surgery, ≤90% symmetry in quadriceps size and strength) and nine uninjured controls volunteered. ACLR participants exercised at home for 25 min, 5×/wk for 4 wks (single-leg knee extension, bodyweight half-squats, walking). Blood flow in only the involved leg was restricted using a thigh cuff inflated to 50% of limb occlusion pressure. Rectus femoris and vastus lateralis thickness and knee extensor strength were measured before and after training. Baseline and post-training symmetry (involved leg/uninvolved leg) indices were compared to uninjured controls. Rectus femoris and vastus lateralis thickness and knee extensor strength in the involved leg increased by 11±5%, 10±6%, and 20±14%, respectively (all P<0.01). Compared to baseline, post-training knee extensor strength symmetry increased from 88±4 to 99±5% (P<0.01) and did not differ from uninjured controls (99±5%, P=0.95). Implementation of BFR exercise at home was feasible, safe and effective. Results extend upon early post-operative application of BFR exercise for ACLR recovery and demonstrate that BFR can improve quadriceps function long after ACLR.

Background and Purpose After total knee arthroplasty (TKA), persistent quadriceps muscle atrophy and weakness impairs physical function. Blood flow restriction (BFR) exercise is emerging as a potential method to improve muscle size and strength in clinical populations with orthopedic limitations. There are no randomized controlled studies documenting BFR exercise after TKA. This case report describes the use of home-based BFR exercise to increase quadriceps size, strength, and physical function after TKA. Case Description A 59-year-old man (6 months post-TKA) performed body weight and walking exercises with BFR 5×/wk for 8 weeks. Blood flow in the TKA leg was restricted using a thigh cuff inflated to 50% of limb occlusion pressure. Lean leg mass, vastus lateralis thickness, knee extensor strength, and physical function were measured at baseline (6 months post-TKA), posttraining (8 months post-TKA), and long-term follow-up (14 months post-TKA). Outcomes After training, lean leg mass, vastus lateralis thickness, and knee extensor strength in the TKA leg increased by 4%, 14%, and 55%, respectively. Compared with baseline, posttraining knee extensor strength symmetry (TKA/uninvolved leg) increased from 64% to 98%. The patient’s performance improved for the 30-second chair stand, 40-m fast walk, and 6-minute walk tests. Increased quadriceps and physical function were maintained at the long-term follow-up. Discussion With enhanced quadriceps and physical function, the patient resumed independent physical activity. Muscle and strength gains surpassed those typically reported after TKA. Outcomes suggest that home-based BFR exercise was feasible, safe, and effective. BFR exercise after TKA is promising and warrants further research.

No abstract