Development of an Outcome Score for Patients With Knee Osteoarthritis and Knee Joint Endoprosthesis Using an App

NCT07212699 | Not Yet Recruiting

• 1 other identifier: KneeApp
• Study Type: interventional
• Target: 450
• Locations: 1 country
• Sites: 1

Brief Summary

Total knee arthroplasty (TKA) is one of the most frequent orthopedic procedures. Over 50% of patients report higher expectations than their surgeons, and 10-50% remain dissatisfied postoperatively. Persistent pain, functional limitations, and unmet expectations are key drivers. Identifying risks pre- and early postoperatively is essential, alongside empowering patients through self-management. Existing scoring systems integrate PROMs, demographics, and sometimes imaging but within limited timeframes. They rarely capture functional deficits or long-term trajectories. Digital health solutions for TKA (pre-)rehabilitation exist, yet most focus on physiotherapy and education rather than predictive outcome modeling. To address this gap, the study team has developed a novel mobile application that enables the documentation and analysis of movement data up to 10 years before surgery and throughout long-term follow-up. These data are combined with PROMs and functional test results, providing a unique basis for outcome prediction and risk stratification in TKA. Primary Objective The aim of this pilot study is to develop a composite outcome score for TKA patients. This score will integrate demographic variables, PROMs, and objective functional measures (knee joint angles, gait parameters, walk tests) to identify risk factors for dissatisfaction and support predictive modeling. A machine learning algorithm will be trained using the collected dataset to predict patient satisfaction after TKA. Endpoints Primary endpoint: Overall patient satisfaction Secondary endpoints: Age, height, weight, step count, step length, gait asymmetry, gait speed, double support phase, knee joint ROM, walk test, KOOS, SF-36, satisfaction with the app, and satisfaction with app use. Study Population Inclusion criteria are patients ≥18 years before or after TKA. Exclusion criteria include missing consent, ineligible diagnosis, lack of iOS smartphone, age \<18 years, or insufficient German language skills (as no English version of the app is currently available). Planned enrollment: 450 patients. Methods Design: Single-center, prospective pilot study. The app collects patient-authorized movement data already stored on smartphones as well as future data. Participants choose which data to share. In addition, they are prompted to complete gait tests and knee function tests. PROMs (KOOS, SF-36, satisfaction) are administered at regular intervals.

Conditions

Knee Osteoarthritis; Knee Arthroplasty

Keywords

knee; app; arthroplasty; detection; risk score

Outcome Measures

Primary Outcomes (1)

• overall patient satisfaction

  satisfaction scale minimum: 0 = not satisfied, maximum: 5 = fully satisfied

  through study completion, an average of 1 year

Secondary Outcomes (13)

• age

  through study completion, an average of 1 year

• sex

  through study completion, an average of 1 year

• height

  through study completion, an average of 1 year

• Weight

  through study completion, an average of 1 year

• KOOS

  through study completion, an average of 1 year

Study Arms (1)

KneeApp Arm

EXPERIMENTAL

Group which is using the app before and after TKA

Other: KneeApp

Interventions

KneeApp OTHER

Our app collects patient-authorized mobility data that are already stored on the patient's smartphone and those that will be recorded in the future, and analyzes these data with respect to their temporal patterns. Each study participant can decide individually which data they wish to share. In addition, participants are prompted at regular intervals to perform and document functional tests, such as gait assessments (once per month) and knee function tests (weekly). Furthermore, subjective health data are regularly collected using standardized PROMs: KOOS and SF-36 every three weeks, patient-reported satisfaction with health status on a monthly basis, and user satisfaction with the app every three months. The collected data can be accessed both by the patient and the study team and can be downloaded and stored as a PDF file if needed. Participation in the study requires a single on-site visit at the Department and Outpatient Clinic of Orthopedics and Sports Orthopedics. No further in-pe

KneeApp Arm

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• aged 18 years or older
• before or after implantation of a knee joint prosthesis
• or with a diagnosis of knee osteoarthritis.
• german speaking
• signed informed consent
• using own smartphone with iOS operating system

You may not qualify if:

• age below 18 years.
• Lack of informed consent
• no smartphone with iOS operating system
• non-German-speaking

Sponsors & Collaborators

• Technical University of Munich: lead

Study Sites (1)

Department of Orthopaedics and Sports Orthopaedics TUM University Hospital Rechts der Isar

Munich, Bavaria, 81675, Germany

Location

MeSH Terms

Conditions

Osteoarthritis, Knee; Alzheimer Disease

Condition Hierarchy (Ancestors)

Osteoarthritis; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Dementia; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Tauopathies; Neurodegenerative Diseases; Neurocognitive Disorders; Mental Disorders

Study Officials

• Rüdiger von Eisenhart-Rothe, Univ.-Prof. Dr. med.

  Department of Orthopaedics and Sports Orthopaedics, TUM University Hospital Rechts der Isar

  STUDY DIRECTOR

Central Study Contacts

Christina Valle, Dr. med

CONTACT

+498941406508; christina.valle@tum.de

Florian Hinterwimmer, Dr. rer. nat.

CONTACT

florian.hinterwimmer@tum.de

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: SCREENING
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Dr. med.

Model Details: Monocentric prospective single-group pilot study

Study Record Dates

• First Submitted: September 23, 2025
• First Posted: October 8, 2025
• Study Start: October 1, 2025
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): August 31, 2028
• Last Updated: October 8, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

DE (1)