The Efficacy of Low-load Blood Flow Restricted Resistance Before TKR

Study Overview
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Brief Summary
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The primary aim of this study is to investigate the efficacy of 8 weeks of Low-load blood flow restricted exercise (BFRE) compared to receiving standard care only (no preoperative training) before total knee replacement (TKR) on postoperative 30-seconds chair stand test (30s-CST). We hypothesize that 8 weeks of preoperative BFRE will increase chair stand performance 3 months postoperatively. Secondary aims are to investigate the efficacy of 8 weeks of preoperative BFRE compared to receiving standard care only on changes in muscle strength 3 months after TKR and investigate associations to functional capacity and quality of life. Furthermore, it will be investigated if 8 weeks of BFRE induces muscle hypertrophy and increases satellite cell and myonuclei content of the vastus lateralis muscle.

Detailed Description
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BFRE is resistance training with low loads (30% 1repetition maximum (RM) performed with concurrent partial blood flow restriction by means of pneumatic cuff compression around the working limb. Group 1 (BFRE): BFRE group: Will perform 3/weekly supervised BFRE sessions for 8 weeks from a physiotherapist educated in administering BFRE. Each session will consist of a 10-min warm up followed by two different unilateral lower-limb resistance training exercises: leg press and knee extension. Each exercise will be performed with the affected lower limb only and consist of 4 rounds interspaced by 30 seconds of rest. 1st round: 30 repetitions (reps); 2nd round: 15 reps; 3rd round: 15 reps; 4th round: until exhaustion. Between each exercise the patients will rest for 5 minutes without blood flow restriction. Patients will rest in a standardized resting position between each set to maintain the desired resting cuff-pressure. The occlusion pressure will be set at 60% of total limb occlusion pressure and starting load intensity will be 30% 1repetition maximum (1RM) in both exercises. If patients can perform more than 15 repetitions in the 4th exercise set, the exercise load will be increased with the minimum extra load possible. Group 2 (control Group): CON group: Will follow standard procedures before a TKA and be encouraged to live their lives as usual up until TKA. The study is a multicenter (2 sites), randomized (allocation 1:1), assessor blinded, controlled trial Outcomes will be measured at baseline (9-10 weeks before surgery), in the week of surgery and 3- and 12 months postoperatively. Muscle biopsies will be taken from all patients undergoing surgery at Horsens Regional Hospital. Muscle biopsies will be taken at baseline, during surgery and 3 months postoperatively. The 12 months follow-up assessment will be analyzed and presented in papers during a subsequent Post Doc-period. All patients will be scheduled to receive TKR and receive a standard multimodal surgical program with standardized perioperative care. Specifically, all patients will be invited to a preoperative information meeting 2-3 weeks prior to surgery where nurses, surgeons, and physiotherapists will be providing detailed information about pain management, nutrition, the surgical procedure (i.e. basic knowledge about a prosthesis, risks related to smoking, restrictions related to living with a TKR, long-term results, and living with a TKR), physical activity, postoperative home-based rehabilitation, load-management, etc. On the day of surgery patients will be hospitalized at one of the two orthopedic departments and TKR procedures will be performed by an orthopedic surgeon. The day after surgery patients will be trained once or twice per day by a physiotherapist towards fulfilling the following discharge criterions: independency in in-and-out of bed and sit-to-stand activities, independency in walking and stair-negotiation with crutches, ADL activities, and home-based exercises during the hospitalization period. Patients will generally be discharged within  1-2 days after fulfilling all the above discharge criteria. After discharge, all patients will receive a standard home-based rehabilitation program aimed at increasing knee mobility and lower extremity muscle strength. However, if considered necessary by the physiotherapist in charge of the patient, patients can receive additional supervised knee-specific exercise therapy at private physiotherapy clinics, municipal rehabilitation centers, or specialized hospital-based rehabilitation.

Official Title
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The Efficacy of Low-load Blood Flow Restricted Resistance Exercise in Patients With Knee Osteoarthritis Scheduled for Total Knee Arthroplasty: A Multicenter, Randomized Controlled Trial

Conditions
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Total Knee Replacement

Intervention / Treatment
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* Other: Low-load blood flow restricted exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients ≥ 50 years scheduled for TKA at Horsens- or Silkeborg Regional Hospital. Exclusion Criteria: Severe cardiovascular diseases (New York Heart Association class III and IIII), previous stroke incident, thrombosis incident Traumatic nerve injury in affected limb Unregulated hypertension (Systolic ≥180 or diastolic ≥110 mmHg) Spinal cord injury Pregnancy Planned other lower limb surgery within 12 months Cancer diagnosis and currently undergoing chemo-, immuno-, or radiotherapy Inadequacy in written and spoken Danish an existing prosthesis in the index limb living more than 45 minutes from either Horsens Regional Hospital or Silkeborg Regional Hospital.

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group 1 (BFRE)<br>Low-load blood flow restricted exercise 3/weekly for 8 weeks before TKR 10-min warm-up followed by unilateral leg press and unilateral knee extension | Other: Low-load blood flow restricted exercise<br>* Leg press and knee extension exercise 3 times per week for 8 weeks. Repetition scheme: 30-15-15-until exhaustion interspaced by 30 sec rest. 5 min free-flow rest between exercises<br>|
| No Intervention: Group 2 (CON)<br>No training before TKR | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 30-seconds chair stand test (30-sec CST) | The 30s-CST measures the number of sit-to-stand repetitions completed within 30 seconds. Patients will be instructed to perform a sit-to-stand movement starting from a seated position (seat height 43 cm without armrests) having the feet placed flat on the floor shoulder width apart, and arms crossed on chest to a standing position (hip and knee joints fully extended) repeated as many times as possible for 30 seconds. | change in 30-sec CST from baseline to 3 months after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Timed Up & Go | The TUG assesses the time required for patients to stand from a chair (seat height 46 cm) walk around a tape mark 3 meters away and sit into the chair at return. | Measured at baseline, in the week of surgery, 3 months after surgery, and 12 months after surgery | 
| 4x10 meter fast-paced walk test (40m-FWT) | The 40m fast-paced walk test (40m-FWT) measures the total time taken to walk 4 x 10 m excluding turns (meter/sec). | Measured at baseline, in the week of surgery, 3 months after surgery, and 12 months after surgery | 
| 1RM leg press strength | 1 Repetition maximum (RM) is the maximal load (kg) a patient is able to concentrically press in the leg press machine. The 1RM will be estimated from a 5-8RM leg press test. The 1RM will be calculated as [1RM = load (kg)/1.0278-0.0278·number of repetitions) | Measured at baseline, in the week of surgery, 3 months after surgery, and 12 months after surgery | 
| 1RM knee extension strength | 1 Repetition maximum (RM) is the maximal load (kg) a patient is able to concentrically lift in the knee extension machine. The 1RM will be estimated from a 5-8RM leg press test. The 1RM will be calculated as [1RM = load (kg)/1.0278-0.0278·number of repetitions) | Measured at baseline, in the week of surgery, 3 months after surgery, and 12 months after surgery | 
| Isometric knee extensor strength | Isometric knee extensor muscle strength will be assed with the participants seated on a examination table with knees and hip positioned at 90 degree flexion. Assessment of muscle strength will be performed with a hand-held dynamometer, fixed with an adjustable rigid belt to the examination table. | Measured at baseline, in the week of surgery, 3 months after surgery, and 12 months after surgery | 
| Isometric knee flexor strength | Isometric knee flexor muscle strength will be assed with the participants seated on a examination table with knees and hip positioned at 90 degree flexion. Assessment of muscle strength will be performed with a hand-held dynamometer, fixed with an adjustable rigid belt to the examination table. | Measured at baseline, in the week of surgery, 3 months after surgery, and 12 months after surgery | 
| Muscle biopsy sampling and analysis - myofiber morphology (cross sectional area, fiber type composition, myonuclei number) and myogenic stemm cell (satellite cell) content | needle biopsies (100-150 mg) will be obtained from the vastus lateralis muscle of patients undergoing TKR at Horsens Regional Hospital | Measured at baseline, in the week of surgery, and 3 months after surgery | 
| Knee disability and Osteoarthritis Outcome Score (KOOS) | KOOS is a patient-administered knee specific questionnaire comprising five subscales Pain; Symptoms; Activities of daily living; Sport & Recreation; and Knee-Related Quality of Life. | Measured at baseline, in the week of surgery, 6 weeks after surgery, 3 months after surgery, and 12 months after surgery | 
| EuroQol Group 5-dimension (EQ-5D-5L) | The EQ-5D-L5 is a self-completion questionnaire consisting of two parts; first part of the EQ-5D-5L comprises five dimensions involving mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. | Measured at baseline, in the week of surgery, 6 weeks after surgery, 3 months after surgery, and 12 months after surgery | 
| Adverse events | Adverse events will be defined as unpredicted or unintended events, signs, or disease occurring during the period from inclusion until the 3-month follow-up (primary end-point) resulting in contact with the healthcare system (hospital or general practitioner) independent of whether or not the event is related to the intervention or outcome assessments | 3 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Low-load blood flow restricted exercise, Preconditioning, Functional capacity