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Is it time to develop specific return to running criteria for ACL rehabilitation? An international survey of physiotherapists criteria for return to running following ACL injury

Sayer, T.A., van Melick, N., Riera, J., Jackson, J., Bryant, A., Bogie, R., Cross, N., Edouard, P. and Rambaud, A., 2024. Is it time to develop specific return to running criteria for ACL rehabilitation? An international survey of physiotherapists criteria for return to running following ACL injury. Physical Therapy in Sport, 67, pp.19-24.

In today’s letter

• Overview of what 476 physiotherapists believe a return to running criteria should look like

• Rapid Results = A return to running criteria(s) are lacking in objective data and are mostly associated with time. More research is needed to understand optimal return to running protocol post ACL injury

• 3 Reads to check out to further you knowledge about running post ACL injury

• Meme of the week: I would like job at paediatrics please 👪

Aim of the study

The goal of this study was to find out what criteria physiotherapists in Australia, the Netherlands, and France are currently using to decide if their patients are ready to start running again after ACL injury

Did you know?

• Returning to running after an ACL injury or reconstruction has traditionally been seen as a straightforward step in recovery.

• Most clinical guidelines suggest that patients can start running again about 3 months after ACL surgery - which is time based decision (This is a big no no in this day and age)

The approach may lead to patients returning to running while still having deficits in:

1. Strength

2. Neuromuscular control

3. Power (Rate of force development for the S&C guys 😆)

In the muscles around the knee. This can lead to poor running mechanics.

• Changes in running mechanics can alter how force is applied to the knee, potentially affecting the health of the tissues

• Very few studies have looked into the specific criteria that should be used to determine when patients are ready to return to running after an ACL injury or surgery.

• Rambaud et al.'s review found that over 80% of studies mainly used time since surgery as the deciding factor

 Methods

Study design

• The authors performed a cross sectional international survey exploring physiotherapists’ return to running criteria after ACL injury or ACL reconstruction.

The survey

• The survey was made up of 22 questions, split into two sections.

• The first section aimed to gather information about the physiotherapists, such as their qualifications, years of experience, area of practice, and the number of ACL patients they treat each month.

• The second section focused on finding out the current methods physiotherapists in Australia, the Netherlands, and France use to determine when patients are ready to return to running after an ACL injury or reconstruction.

• This section included both multiple-choice and open-ended questions to get a detailed understanding of their practices.

• The survey was created by physiotherapists with expertise in ACL injuries, with the main goal of identifying international clinical standards for returning patients to running after an ACL injury or surgery.

Participants

• Physiotherapists were recruited by advertising the survey through LinkedIn and through affiliated physiotherapy organisations in each country.

Results

A total of 476 physiotherapists took part in the survey, with participants from Australia (153), the Netherlands (162), and France (161).

The educational levels varied across the countries: Australia had the highest percentage of qualified physiotherapists (72%), followed by France (55%), and the Netherlands (5%)

Return to running criteria

• There was a wide variety of responses regarding the criteria for returning to running after an ACL injury.

• For patients who did not undergo surgery, the most common criteria across all countries were swelling (40.6%) and pain (38.2%).

• For patients who had surgery, the top criteria were similar, with swelling (41.18%) and pain (37.2%) being the most frequently mentioned.

• In terms of performance and strength criteria, the non-surgical group prioritised quad strength (34.3%), single-leg squat (31.9%), and hamstring strength (29.8%).

• For those who had surgery, the criteria included quad strength (37.2%), single-leg squat (33.2%), and additional factors like drop vertical jump (26.7%), surgeon clearance (22.5%), time from injury (22.5%), and the ACL-RSI questionnaire (23.7%)

8 Common themes

1. Clinical examination (irritability, range of motion, strength, and pain)

2. Biomechanics

3. Functional/performance tests

4. Patient-reported outcomes

5. Time since injury

6. Medical clearance

7. Passive stability

8. Other factors.

For both non-operative and postoperative patients, the most emphasised theme was functional/performance tests, followed by clinical examination and biomechanics.

In the functional/performance category, common focus areas included “core control in jumping and landing,” “mobility,” and “vertical hop height.”

For clinical examination, key aspects mentioned were:

1. Range of motion

2. Isokinetic testing —> or using a hand held dynonometer as the isokinetic machines are a little expensive

3. 6RM eccentric knee extension strength at 70% body weight (I.e single leg squat or knee extension machine)

4. Calf raise endurance > 25 reps both legs

For biomechanics:

• “gait mechanics” and “running analysis” were frequently cited for both non operative and operative treatment

Benchmarking

Both non-operative and operative management had similar responses, with one little difference. No swelling was on the check list for the Post-op patients.

This is what the clinicians highlighted as important

• In clinical examination tests, pain was the most frequently mentioned factor, with 12 respondents (2.8%) selecting 0/10 pain, followed by 9 respondents (1.8%) choosing pain less than 2/10.

• For effusion (swelling), the most cited was "no effusion" (32 out of 34 responses), while 2 respondents used "swipe test < grade 1+" as their criterion.

• Range of motion were the 3rd most cited, with 19 respondents (3.9%) mentioning this factor. The most common criterion was "full knee extension range of motion."

• In functional/performance tests, strength symmetry was the most used criterion, with values greater than 70% limb symmetry index (LSI) cited by 15 respondents (2.5%), followed by greater than 90% LSI cited by 12 respondents (3.1%).

• Hop test symmetry was the second most mentioned performance criterion, with 19 responses. The most common values were 90% LSI (8 responses, 1.6%) and 70% LSI (5 responses, 1%).

• The time since surgery was another popular criterion, with "more than 12 weeks" being the most frequently mentioned.

Discussion

• Despite differences in experience levels across countries, most respondents (83-90%) worked in private clinics and typically treated 1 to 10 ACL patients per month.

• The study showed that the majority of clinicians used pain, swelling, knee extensor strength, and single-leg squat as key criteria for determining when patients can return to running, both for non-operative and post-operative patients.

• However, there was a notable lack of specific cutoff criteria for these variables, with only 32% of respondents providing such criteria.

• Commonly cited cutoff criteria within this group included pain less than 3/10, swelling less than grade 1+, and functional hop and strength tests showing more than 70% limb symmetry.

• While these findings offer some guidance, the study argues that these criteria do not provide a comprehensive benchmark for ensuring a safe return to running.

• Running primarily involves movements in the sagittal plane, with braking (eccentric) and propulsive (concentric) forces. None of the variables or cutoff criteria identified in this study address bio-mechanical factors or specific strength and power-based criteria.

• It's well-known that the mechanics of the hip and ankle joints play a significant role in knee loading, such as the soleus muscle reducing tibio-femoral contact force and ACL strain during

Top 3 resources

To further your knowledge about ACL’s, rehab and return to running/sport

1. Objective testing for return to participation - LINK

2. More criteria to check out build your return to running protocol - LINK

3. 3 categories to cover for returning people to sport post lower limb injury (video) - LINK

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