The Effect of Postoperative "Peanut Ball" Rehabilitation After Total Knee Replacement.

The Effect of Postoperative Rehabilitation With a "Peanut Ball" After Total Knee Replacement. A Randomized Study Evaluating Postoperative Pain and Knee Function.

The purpose of this randomized controlled study is to evaluate the effect of postoperative exercise with a "peanut ball" after total knee replacement, on pain, intake of pain killers, knee function, and health-related quality of life.

Study Overview

• Status: Completed
• Conditions: Knee Osteoarthritis
• Intervention / Treatment: Other: Exercise

Detailed Description

After being informed about the study and potential risks, all patients giving written informed consent will be included in the study.

At baseline, before surgery, all patients will meet a nurse, a physical therapist, and an orthopedic doctor and answer questions about their health condition and do functional tests.

Each week is randomized to be either "peanut ball" or standard exercise week, with all patients during that week receiving the same treatment. Thus, depending on what week the patients are operated they will be mobilized with postoperative exercise with a "peanut ball" or to a standard exercise program (no peanut ball) 3-5 times/day for 6 weeks. All patients randomized to exercise with a "peanut ball" will receive a ball for free to bring home.

At the ward, the nurses will ask about the patient's pain level two times a day and register all medicines. The physical therapist will introduce the exercise and inform the patients to do the exercise 3-5 times/day a´ 15 minutes and fill in all exercises in an exercise diary.

2 weeks after surgery all patients have a standard visit to a nurse and a physical therapist at the orthopedic department. At this visit, the nurse will register the pain level and all intake of medicine and the physical therapist will measure the range of movement and the sit to stand test.

3 months after surgery all patients have a standard visit to a physical therapist at the orthopedic department. At this visit, all outcomes will be filled in or measured.

• Study Type: Interventional
• Enrollment (Actual): 300
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Lund, Sweden
    • Region Skane, VO ortopedi

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 90 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with osteoarthritis planned for surgery with total knee replacement at Skåne University Hospital.

Exclusion Criteria:

• Patients who do not understand and talk the Swedish language
• Patients with dementia
• Revision surgery of the knee
• Unicompartmentmental knee replacement

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Exercise with a "peanut ball".; The rehabilitation program consists of mobility- and functional training exercises with a "peanut ball".	Other: Exercise; Post-surgical exercise
Active Comparator: Exercise without "peanut ball"; The rehabilitation program consists of standard mobility- and functional training exercises without a "peanut ball".	Other: Exercise; Post-surgical exercise

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual analogue scale (VAS) (0-100)	The scale is from 0-100 and a higher value is associated with more pain. 0:no pain and 100: most possible pain.	Change from baseline (before surgery) to 3 months after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Range of movement	The range of movement in the knee is measured with a goniometer. The range of movement may be between 0 degree to 145 degree. A higher degree is better.	Change from baseline (before surgery) to 3 months after surgery
Forgotten Joint Score (FJS)	Is a questionnaire of the patients awareness of their knee. Minimum score:0 (worse outcome), maximum score 100 (best outcome)	Change from baseline (before surgery) to 3 months after surgery.
Knee injury and Osteoarthritis Outcome Score (KOOS-12)	Is a questionnaire of knee related function an quality of life. It consists of three parts: pain (4 items), function (4 items) and knee-specific quality of life (4 items). KOOS-12; in pain sub-item; In the sub-item of walking on a flat ground, going up and down stairs, sitting-reaching, function and daily life; There are patient-specific questions in the sub-item of quality of life, sitting up, standing, getting in and out of the car, turning the affected knee. The total scores obtained from the items in the KOOS-12 scale are calculated and the average of the total score is taken from the three sub-dimensions. If any of the three sub-item scores are missing, the average score cannot be calculated.	Change from baseline (before surgery) to 3 months after surgery.
30 second sit to stand test	A test to evaluate leg strength and endurance. The 30 second stair stand asks participants to rise and sit back down in a chair as many times as they can during that time period, without using hands or arms for support. Higher scores mean better outcome (e.g. more stands in 30 seconds).	Change from baseline (before surgery) to 3 months after surgery.
Euro Qol-five dimensions, Visual analogue scale (EQ-5D VAS)	Is a generic questionnaire about health related quality of life, 0-100, 0: The worst health you can imagine", 100: "the best health you can imagine". Patients are asked to indicate how your health is today and to write the number in an adoining box.	Change from baseline (before surgery) to 3 months after surgery.

Collaborators and Investigators

• Sponsor: Region Skane

Study record dates

Study Major Dates

• Study Start (Actual): January 10, 2021
• Primary Completion (Actual): December 30, 2023
• Study Completion (Actual): December 30, 2024

Study Registration Dates

• First Submitted: November 16, 2021
• First Submitted That Met QC Criteria: November 16, 2021
• First Posted (Actual): November 30, 2021

Study Record Updates

• Last Update Posted (Actual): July 16, 2025
• Last Update Submitted That Met QC Criteria: July 13, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Knee
• Other Study ID Numbers: 2021-02904

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No