Recruitment problems

The objective of this study is to evaluate the regaining of a normal gait within the early rehabilitation (12-13 weeks postsurgical) after reconstruction of the anterior cruciate ligament (ACL). Therefore, two different rehabilitation programs (supervised versus home-based) will be compared.

A prospective, parallel-grouped trial with patients´ free choice of postsurgical therapy (home based versus supervised) will be conducted. One group will receive a well supervised, standardized rehabilitation program, while the other group will be instructed in a home-based rehabilitation program. Gait assessments will be carried out 6-7 weeks and 12-13 weeks postsurgical using standard 3D clinical gait analysis. Complementary, gait will also be evaluated using an Inertial Measurement Unit (IMU) three times postsurgical (6-7 weeks, 9-10 weeks, 12-13 weeks). Furthermore, various clinical parameters, like patient reported outcome measures (PROM), knee swelling, range of motion (ROM) will be taken presurgical as well as on days of gait assessment.

The study will show the impact of physiotherapeutic therapy on the early normalization of gait after ACL reconstruction. The results may help to build a better understanding of the required physiotherapeutic supervision after ACL surgery and if a home-based therapy can safely be recommended to specific patients.

Design:

The study is designed as a prospective, parallel-grouped trial. The patient will have the free choice out of two postsurgical rehabilitation regimens. The baseline assessments will take place presurgical after the official enrolment procedure. After surgery, three follow ups are set (6-7, 9-10, 12-13 weeks postsurgical). 3D gait analysis will be performed on first and third series. Additionally, IMU gait analysis as well as the modified Star Excursion Balance Test (SEBT) will be performed . Furthermore, various clinical parameters, like patient reported outcome measures (PROM), knee swelling, range of motion (ROM) will be taken on assessment days.

Enrolment/Allocation/Blinding:

An appointment for checking eligibility will be made presurgical. If the patient is eligible, a signed informed consent will be collected and a continuous identification number will be defined by a central study coordinator. Further, the general personal data will be assessed, and presurgical measurements (e.g. ROM, knee swelling, PROM, height, weight) will be performed.

After surgery the patients can choose between a standardized rehabilitation program at the department of physical medicine and rehabilitation at University Hospital Krems (UHK) or a supervised home-based program.

A blinding of the patients is not possible, due to the nature of the study and the obviosity of group allocation. The principal investigator will be blinded to the allocation and will only get access to the coding list in special cases (e.g. harm). Furthermore, the principal investigator is not involved in the statistical analysis of data.

Rehabilitation programs:

Therapy Focus (both Groups):

Stationary setting: Reduction of swelling, gait training with crutches, introduction to a CPM (continuous passive motion) machine, instruction to exercises for home practice (active flexion and extension), stretching of ischiocrural muscles and M. iliopsoas From 2nd week postsurgical: Mobilisation of the patella, mobilisation of scars, gait training (beginning with partial weight-bearing), improvement of range of motion, progression of soft strengthening of knee flexion and extension.

From 6th week postsurgical: Focus on sensomotoric exercises. Progression of exercises for knee flexion and extension and intensified strengthening

Phase-adapted exercises for home-based Training:

Week 1-2:

1. Local cryotherapy (3x 20 min)
2. Mobilization of scars (after wound closure)
3. Active knee extension in supine position
4. Active knee extension in supine position with padding underneath the heel
5. Active knee extension in prone position
6. Active knee flexion and extension in closed chain in supine position (heel contact with floor)
7. Activating of M. quadriceps femoris and ischiocrural muscles by tensing

Week 3-6:

1. Local cryotherapy (3x 20 min) after exercise, if required

2. Active knee extension in supine position without padding

3. Progression: full knee extension while standing/half seated

4. Active knee extension in supine position with padding underneath the heel

5. Active knee extension in supine position in open chain (no floor contact of the foot)- max. 20° flexion

6. Knee flexion and extension in closed chain in supine position (heel contact to the floor), with TheraBand

7. Activating M. quadriceps and ischiocrural muscles with foot-support on the wall in

   • 30° knee-flexed position/ 60-90° knee-flexed position

8. Mini-Squats (holding on a chair back)

9. Bridging- extending the knee, while lying supine with raised pelvic

10. Raising the operated leg lying in lateral position with extended knee/ with flexed knee

11. Knee extension and load takeover without crutches in standing Position

Week 7-8:

1. Local cryotherapy (3x 20 min) after exercise, if required
2. Active knee extension in supine position with padding underneath the heel
3. Active knee extension in supine position in open chain (no floor contact of the foot)- max. 20° flexion
4. Active knee flexion and extension in closed chain in supine position (progression: with gymnastic ball)
5. Activating M. quadriceps and ischiocrural muscles with foot-support on the wall (or to progress on gymnastic ball) in 30° knee-flexed position/ 90° knee-flexed position
6. Knee extension and flexion in seated position in closed chain. Extension against resistance of TheraBand
7. Squats (30°-0° flexion/ 80°-60° flexion)
8. Bridging- extending both knees alternately, while lying supine with raised pelvic
9. Extension of knee and hip in lateral position (on healthy side) with contact of injured limb with the wall
10. Standing on one foot
11. Walking frontwards and backwards with active extended knees

Week 9-10:

1. Local cryotherapy (3x 20 min) after exercise, if required
2. Active knee extension in supine position with padding underneath the heel
3. Active knee flexion and extension in closed chain in supine position
4. Knee extension and flexion in seated position in closed chain (heel contact with floor) with eyes closed. Extension against resistance of TheraBand.
5. Squat lunges to the side. The knees are alternately flexed, while the toes of the contralateral limb tip the floor to the side.
6. Bridging- extending both knees alternately, while lying supine with raised pelvic
7. Standing on one foot, while the other knee is flexed 90° and the foot pushes against a wall behind
8. Standing on one foot, doing different exercises with the upper body (e.g. arm movement, head rotation)
9. Walking frontwards and backwards with active extended knees
10. Planking on forearms (exercise time increases)

Week 11-12:

1. Cryotherapy, if required
2. Active knee flexion and extension in closed chain in supine position
3. Variation of Squats (eyes closed, arm movement, full knee ROM, stabilizing in 60°/90° flexion)
4. Variation of Squat lunges to the side (eyes closed, arm movement, rotation of upper body, stabilizing in 90° flexion)
5. Lunges moving forward
6. Standing on one foot, ankles connected with TheraBand. Moving free limb back and to the side against resistance of TheraBand. Difficulty increases with different arm tasks or closed eyes.
7. Standing on one foot, doing different exercises with the upper body (e.g. arm movement, head rotation)
8. Variation of lunges
9. Stride leaps
10. Planking on forearms

Independently of group allocation, each patient is offered a prescription of an electrotherapeutic device (Schuhfried Company, Vienna, Austria) with two electrodes (8x12cm) for quadriceps muscle strengthening with surge current for home application.

Training diaries:

Patients of both rehabilitation programs will be encouraged to keep training diaries to monitor progression in load increase, repetitions of exercises and frequency in the period of home training. Additional treatments shall also be documented (e.g. surge current). The diaries between the groups differ, as the standard-group will receive only one general sheet to document their training for the whole study period, while the home-based group will receive an extra sheet for every phase (5 documents), where all exercises can be selected separately.

Ethical aspects:

All participants will be informed about the nature and the scope of the study and will give a written consent. The trial has been registered and received an ethical approval of the Committee for Scientific Integrity and Ethics of the Karl Landsteiner University Krems. The registration number is 1038/2019. Participants may withdraw from the study anytime, without giving a specific reason. Furthermore, if a participant may take obvious physiological harm by staying within the study protocol, the principal investigator can decide to remove him/her from the study.

Sample size calculation and statistical procedures:

For the statistical analysis a matched pair t-test will be used. The matching criteria will be the Tegner score (maximum one point difference) and the age of the participants (maximum five years difference).

The required number of patients was calculated beforehand using the software nQuery version 8.5. The sample size estimation is based on the primary outcome parameter (step length symmetry) after a literature review. According to the calculation 24 pairs are needed to detect a statistical effect size of 0.6 with a power of 80 percent. Considering the usual drop-out rates and the impossibility of finding matching partners, for estimated a third of the participants, the sample size was set with 45 persons per group.

Inclusion Criteria:

• Surgery at University Hospital Krems (UHK), Austria
• Age 18-60 years
• Surgery-timing less than six months posttraumatic
• Isolated ACL rupture with or without small concomitant injuries

Exclusion Criteria:

• Relevant concomitant injuries of the musculoskeletal system
• Old injuries of the lower limbs, which influence the normal gait pattern (including ACL re-ruptures)
• Relevant orthopaedic pre-existing conditions, especially of the lower limbs.
• Severe internistic and neurological concomitant diseases, which have an impact on the cardiorespiratory fitness or the physiologic gait
• Patients who do not speak or understand the German or English language properly

A blinding of the patients is not possible, due to the nature of the study and the obviosity of group allocation. The principal investigator will be blinded to the allocation and will only get access to the coding list in special cases (e.g. harm). Furthermore, the principal investigator is not involved in the statistical analysis of data.