High-intensity resistance training enhances strength, but not muscle mass and physical functioning gains during total Knee arthroplasty rehabilitation

Abstract

Purpose:

To determine whether high-intensity resistance exercise training with nutritional support (RET) during recovery from total knee arthroplasty induces greater improvements in muscle-related outcomes compared with standard rehabilitation (SR) alone.

Methods: Thirty-three patients (70 +/- 6 yr; 28.7 +/- 3.1 kg & sdot;m(-2)) were randomized to receive RET (intervention + regular rehabilitation, n = 18) or SR (regular rehabilitation only, n = 15) for 12 wk, starting 8 wk post-TKA. RET involved supervised, bilateral, high-intensity resistance exercise, 3 & times;/wk, daily supplementation (45 g protein, 5.5 g Vivinal GOS, 800 IU vitamin D, 366 mg calcium), and dietary counseling. Outcomes included bilateral and unilateral leg press one-repetition maximum, DXA-derived appendicular lean mass, computed tomography-derived quadriceps cross-sectional area, 6-min walking test, and 5-times chair-stand test (5CST). Data are mean +/- SD, analyzed with two-way repeated-measures ANOVAs, or median [IQR], analyzed with Wilcoxon Signed-Rank test. Results: Bilateral leg press one-repetition maximum improved to a greater extent following RET (131 +/- 38 to 174 +/- 56 kg; P < 0.001) versus SR (124 +/- 36 to 143 +/- 49 kg, P = 0.018, P value of interaction [P-int] = 0.026). Strength in the nonoperated leg increased in the RET group only (RET: 22% +/- 17%, P < 0.001, SR: 6% +/- 11%, P = 0.175, P-int = 0.002). Operated leg strength increased similarly between groups (RET: 51% +/- 33%, SR: 40% +/- 30%, P value of main time effect [P-time] < 0.001, P-int = 0.338), as did appendicular lean mass (RET: 0.5 +/- 0.8 kg, SR: 0.3 +/- 0.8 kg, P-time = 0.009, P-int = 0.390), and quadriceps cross-sectional area (operated: RET: 7.8% +/- 7.5%, SR: 9.2% +/- 5.9%, nonoperated: RET: 4.8% +/- 4.5%, SR: 3.8% +/- 3.7%, P-time < 0.001, P-int >= 0.557). Six-minute walking test improved more in the SR (428 +/- 94 to 513 +/- 75 m, P < 0.001) versus RET group (417 +/- 69 to 460 +/- 72 m, P = 0.002, P-int = 0.034). 5CST only improved significantly following RET (RET: 15.3 [4.2] to 13.2 [3.9] s, P = 0.039, SR: 14.4 [4.0] to 14.4 [5.1] s, P = 0.064). Conclusions: Compared with standard total knee arthroplasty rehabilitation, high-intensity resistance training with nutritional support induces greater gains in bilateral strength but not muscle mass or physical functioning.