Effects of low-intensity resistance exercise with blood flow restriction after high tibial osteotomy in middle-aged women

Abstract

Background: High tibial osteotomy (HTO) is an effective surgical method for treating medial compartment osteoarthritis. However, in most cases after surgery, muscle strength is decreased, and rapid muscle atrophy is observed. Therefore, the purpose of this study is to verify the effects of low-intensity resistance exercise (LIE) with blood flow restriction (BFR) on the cross-sectional area (CSA) of thigh muscles, knee extensor strength, pain, and knee joint function and investigate proper arterial occlusion pressure (AOP) in middle-aged women who underwent HTO.

Method: This study was designed as a prospective randomized controlled trial. Forty-two middle-aged women who underwent HTO were randomly divided into three groups and participated in LIE with (40% or 80% AOP applied) or without BFR. The main outcome was the measurement of the CSA of thigh muscles (at 30% and 50% distal length of the femur) before and 12 weeks after treatment. Additionally, knee extension muscle strength, pain, and joint function were evaluated before and 6 and 12 weeks after treatment.

Results: CSA of thigh muscles at 30% and 50% distal length of the femur decreased in the AOP 40% and control groups and was the largest in the AOP 80% group 12 weeks after treatment. Knee extension strength increased in all groups and was the highest in the AOP 80% group 6 and 12 weeks after treatment. Pain improved in all groups, with no intergroup differences. Knee joint function improved in all groups and was superior in the 80% AOP group 12 weeks after treatment.

Conclusion: LIE with BFR at 80% AOP was effective in preventing atrophy of the thigh muscle, increasing muscle strength, and improving function. BFR at 40% AOP had no difference in the results when compared with the group in which BFR was not applied. Therefore, LIE with an AOP of 80% is recommended for patients undergoing HTO.

Figure 1.

Application of the blood flow restriction. (A) Measurement of arterial occlusive pressure using Doppler ultrasound. (B) Pulsation of the posterior tibial artery. (C) Strong training system^TM for blood flow restriction. (D) Applying a tourniquet to restrict blood flow to the proximal femur.

Figure 2.

(A) Confirmation of the measurement of the thigh cross-sectional area location using full-length X-ray. (B) Measurement of the cross-sectional area of the thigh at 50% of the distal femur with the free ROI technique in the PACS program. ROI = region of interest.

Figure 3.

The CONSORT flow diagram.

Figure 4.

These graphs show the following results. (A) Cross-sectional area of 30% distal femur (Post hoc: 80% AOP > Control, 80% AOP = 40% AOP, 40% AOP = Control). (B) Cross-sectional area of 50% distal femur (Post hoc: 80% AOP > 40% AOP = Control). (C) Knee extensor strength (Post hoc at 6 weeks and 12 weeks: 80% AOP > 40% AOP = Control). (D) Pain score. (E) Function score (Post hoc: 80% AOP > 40% AOP = Control). (*: P < .05 by the Kruskal–Wallis test). AOP = occlusion pressure.