Validity and Reliability of Video-Based Functional Physiotherapy Assessment of Subacute Knee Injuries

NCT ID: NCT07212920

Last Updated: 2025-10-08

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 138 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-10-01
• Study Completion Date: 2026-12-31

Brief Summary

This study aims to validate a function-based physiotherapy assessment for subacute knee pain without using specific knee tests. Assessments are conducted either in-person or via video consultations in primary care. The study also compares the reliability of digital versus physical assessments to determine if video-based evaluations can provide sufficient diagnostic support and guide treatment decisions.

The main questions this study aims to answer are:

1. Is a function-based knee assessment without specific knee tests valid compared to traditional in-person diagnostics using specific tests?

2. Is a video-based assessment based on history and function-based knee assessment without specific knee tests as valid and reliable as an in-person function-based knee assessment?

3. What is the interrater agreement of function-based knee assessments conducted via video compared to those conducted in person?

Detailed Description

BACKGROUND Knee pain is one of the most common complaints in primary care. Traditional knee assessments include history-taking, evaluation of joint mobility and muscle strength, and specific tests targeting structures such as ligaments and menisci. However, functional tests-such as chair rise or single-leg stance-evaluate the integrated performance of multiple structures and may be more feasible in digital consultations.

Existing literature shows variable validity for specific knee tests, with only a few reaching acceptable thresholds for sensitivity and specificity. In video-based assessments, joint mobility evaluation is reliable, and functional tests are recommended over strength tests. While some knee tests are suggested for digital use, their measurement properties as self-administered tests under physiotherapist supervision remain unclear.

This study will investigate whether a function-based assessment without specific knee tests can provide sufficient diagnostic information and guide treatment decisions for subacute knee injuries. It will also compare the validity and reliability of digital versus in-person physiotherapy assessments in primary care.

METHODS Participants will be consecutively recruited from public and private rehabilitation clinics in the Västra Götaland region of Sweden. Individuals with subacute knee pain (onset between 1 week and 3 months) will be informed about the study through clinics, websites, and online booking systems. Interested individuals will complete a digital screening form to assess eligibility. Those who meet the inclusion criteria will receive written study information and will be able to provide informed consent digitally via Bank-ID.

Demographic data will be collected through the same form, including age, gender, origin, symptom experience, pain intensity and duration, prior video consultation experience, perceived balance, and estimated travel distance to the clinic. This information will support analysis of environmental and accessibility factors.

Eligible participants will be contacted to schedule two knee assessments-one in-person and one via video. Each visit is expected to last approximately 30 minutes, with additional time allocated for preparation and documentation by the physiotherapists.

Inclusion criteria will include age ≥18, subacute knee symptoms, ability to bear weight and flex the knee, no tenderness over patella or fibula, sufficient Swedish language skills, and access to digital technology.

Exclusion criteria will include prior assessment for current symptoms, recent knee or hip surgery, and inability to walk independently.

Sample size calculations indicate that at least 22 participants per diagnostic category (total n=110) will be needed to detect a kappa coefficient of 0.60. With an estimated 20% dropout rate, the target sample size will be 138. Recruitment will continue until minimum group sizes are met or for up to one year.

The study will evaluate the validity and reliability of function-based knee assessments without specific tests, comparing in-person and video-based formats.

Participants will undergo two consecutive knee assessments at a rehabilitation clinic. The first will be a video-based evaluation, including history-taking and functional tests, conducted in real time with the physiotherapist in a separate room. The second will be a traditional in-person assessment, including both functional and specific knee tests. Physiotherapists will use standardized protocols and receive training prior to data collection.

Data collection Participant background data (e.g., age, gender, pain intensity, duration, prior video visit experience, and travel distance) will be collected via a secure web form after consent. Each participant will undergo two knee assessments-first via video, then in person-conducted by the same physiotherapist. Diagnostic agreement between methods will be evaluated, along with physiotherapist confidence and patient satisfaction. Standardized tools include NRS for pain and KOOS-12 for function and quality of life. Secondary outcomes include adverse events, need for further testing or referral, and time required per visit.

Statistical Analysis:

Descriptive statistics will include means, medians, standard deviations, and quartiles. The in-person assessment with specific knee tests will serve as the gold standard. Diagnostic agreement between methods will be analyzed using Cohen's kappa, which will also be used to assess intra-rater agreement. Sensitivity and specificity will be calculated to evaluate the accuracy of assessments without specific tests. Confidence intervals for kappa values will be reported.

Differences in diagnostic certainty level will be analyzed using paired t-test if the data is normally distributed, and wilcoxon signed-rank test if using non-parametric test.

Conditions

Knee Pain

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

Digital assessment first, then face-to-face

Participants undergo two knee assessments: one video-based and one in-person. The video-based exam includes standardized history taking and functional tests without specific knee tests, conducted via clinic software with the physiotherapist in a separate room. The in-person exam follows immediately and includes the same functional tests plus specific knee tests (e.g., ligament, meniscus). After each part, physiotherapists assess whether sufficient information is available to proceed with treatment. All assessments follow standardized protocols, pilot-tested by physiotherapists. Data collection occurs at a public rehab clinic in Västra Götaland, with physiotherapists trained prior to study start.

Group Type: EXPERIMENTAL

Physiotherapy digital assessment

Intervention Type: DIAGNOSTIC_TEST

This study involves three types of knee assessments to evaluate diagnostic reliability and validity: (1) a video-based function-based examination without specific knee tests, (2) traditional in-person function-based examination without specific knee tests and to control with (3) a traditional in-person examination including specific knee tests. The video-based assessment includes standardized history taking and functional evaluation conducted via clinic software, with the physiotherapist and participant in separate rooms. Physiotherapists provide diagnostic judgments after each assessment phase. All procedures follow standardized protocols, pilot-tested and conducted at a public rehabilitation clinic in Västra Götaland.

Physiotherapy assessment - only functional tests

Intervention Type: DIAGNOSTIC_TEST

This study involves three types of knee assessments to evaluate diagnostic reliability and validity: (1) a video-based function-based examination without specific knee tests, (2) traditional in-person function-based examination without specific knee tests and to control with (3) a traditional in-person examination including specific knee tests. The in-person assessments (2 and 3) includes the same functional tests plus specific tests targeting knee structures (ligaments, meniscus etc). Physiotherapists provide diagnostic judgments after each assessment phase. All procedures follow standardized protocols, pilot-tested and conducted at a public rehabilitation clinic in Västra Götaland.

Interventions

Physiotherapy digital assessment

This study involves three types of knee assessments to evaluate diagnostic reliability and validity: (1) a video-based function-based examination without specific knee tests, (2) traditional in-person function-based examination without specific knee tests and to control with (3) a traditional in-person examination including specific knee tests. The video-based assessment includes standardized history taking and functional evaluation conducted via clinic software, with the physiotherapist and participant in separate rooms. Physiotherapists provide diagnostic judgments after each assessment phase. All procedures follow standardized protocols, pilot-tested and conducted at a public rehabilitation clinic in Västra Götaland.

Intervention Type: DIAGNOSTIC_TEST

Physiotherapy assessment - only functional tests

This study involves three types of knee assessments to evaluate diagnostic reliability and validity: (1) a video-based function-based examination without specific knee tests, (2) traditional in-person function-based examination without specific knee tests and to control with (3) a traditional in-person examination including specific knee tests. The in-person assessments (2 and 3) includes the same functional tests plus specific tests targeting knee structures (ligaments, meniscus etc). Physiotherapists provide diagnostic judgments after each assessment phase. All procedures follow standardized protocols, pilot-tested and conducted at a public rehabilitation clinic in Västra Götaland.

Intervention Type: DIAGNOSTIC_TEST

Eligibility Criteria

Inclusion Criteria

• Age 18 years or older
• Subacute knee symptoms (onset more than one week ago but less than three months ago)
• Fulfillment of Ottawa Knee Rule criteria to exclude fractures:

A) Able to bear weight for at least four steps both immediately after injury and at the time of assessment (limping allowed) B) Able to flex the knee to 90 degrees C) No tenderness over the fibular head or patella

• Sufficient proficiency in written and spoken Swedish to complete forms and describe symptoms; no need for interpreter
• Access to digital technology (e.g., computer or smartphone)

Exclusion Criteria

• Prior assessment for current knee symptoms (by rehab clinic, physician, emergency care, or urgent care)
• Knee or hip replacement surgery within the past year
• Other knee surgeries (ACL, meniscus, ligament) within the past year
• Inability to walk independently, with or without walking aids

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Vastra Gotaland Region

OTHER_GOV

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Central Contacts

Chan-Mei Ho-Henriksson, PhD in Medical Sciences

Role: CONTACT

chan-mei.ho@vgregion.se

+460700-82 58 72

Other Identifiers

PTassessment_digital_knee

Identifier Type: -

Identifier Source: org_study_id