Trial results evaluating functional outcomes after knee replacement for osteoarthritis were posted on ClinicalTrials.gov on 2025-10-08. The study enrolled 215 participants to compare different knee implant systems.
Background
Osteoarthritis is a prevalent degenerative joint disease affecting millions worldwide, often leading to pain, stiffness, and reduced mobility. When conservative treatments are no longer effective, total knee arthroplasty (TKA), or knee replacement surgery, is a common and effective intervention to alleviate symptoms and restore function. Given the variety of knee implant systems available, understanding their comparative functional outcomes is important for both clinicians and patients in making informed treatment decisions.
Trial design
This multicenter study, designated as Phase NA, was designed to evaluate functional outcomes following knee replacement surgery in patients with osteoarthritis. The trial, which was terminated, enrolled a total of 215 participants. The study compared the functional results of patients who received a ConforMIS iTotal® CR TKA with those who received an Off-the-Shelf (OTS) system, specifically including DePuy, Zimmer, and Stryker total knee replacements.
Key results
The study evaluated the Functional Activities Subscale Score within the Knee Society Score (KSS) Measure for various knee replacement systems. The results are as follows:
- ConforMIS iTotal Knee Replacement:
- Mean score of 42.34 (Standard Deviation 16.31) units on a subscale.
- Mean score of 77.16 (Standard Deviation 16.47) units on a subscale.
- Mean score of 34.82 (Standard Deviation 21.73) units on a subscale.
- DePuy Total Knee Replacement:
- Mean score of 40.38 (Standard Deviation 13.07) units on a subscale.
- Mean score of 73.65 (Standard Deviation 16.99) units on a subscale.
- Mean score of 33.27 (Standard Deviation 18.28) units on a subscale.
- Zimmer Total Knee Replacement:
- Mean score of 43.56 (Standard Deviation 12.38) units on a subscale.
- Mean score of 88.94 (Standard Deviation 6.20) units on a subscale.
- Mean score of 45.39 (Standard Deviation 13.18) units on a subscale.
- Stryker Total Knee Replacement:
- Mean score of 38.87 (Standard Deviation 13.53) units on a subscale.
- Mean score of 71.20 (Standard Deviation 23.63) units on a subscale.
- Mean score of 32.33 (Standard Deviation 19.21) units on a subscale.
What this means
The posted results provide comparative data on functional activities following total knee replacement with different implant systems for osteoarthritis patients. The Functional Activities Subscale Score within the Knee Society Score (KSS) varied among the tested implants. For instance, one measurement showed the Zimmer Total Knee Replacement group with a mean score of 88.94 (Standard Deviation 6.20), which was the highest observed mean score across all measurements and groups. Conversely, the Stryker Total Knee Replacement group recorded a mean score of 32.33 (Standard Deviation 19.21) in another measurement, representing the lowest mean score reported. These findings highlight differences in reported functional outcomes between the various knee replacement systems, which may be relevant for clinicians and patients considering surgical options for osteoarthritis.
Source
The information for this condition update was sourced from ClinicalTrials.gov, a public database of clinical studies. The trial results for the study "A Multicenter Study to Evaluate Functional Outcome After Knee Replacement" were posted on 2025-10-08 on clinicaltrials.gov.