An interventional study of Condylar Constrained knee system. ( NexGen Legacy Condylar Constrained Knee by Zimmer Biomet) and Rotating Hinge Knee ( NexGen Rotating Hinge Knee by Zimmer Biomet) in Revision Arthroplasty and Knee, sponsored by Medstar Health Research Institute. Recruiting at 2 sites in United States. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-09-14.
Sponsored by Medstar Health Research Institute · Not applicable, Interventional, and Treatment
The primary purpose of this study is to compare reoperation rates for rotating hinge knee implants versus condylar constrained knee implants when used in revision total knee arthroplasty. The secondary purposes are to compare patient satisfaction, loosening rates and clinical outcomes for RHK implants compared to CCK implants in rTKA. Additionally, knee range of motion and stability will be assessed and compared at all follow-up time points. We hypothesize that RHK implants provide patients undergoing rTKA with similar reoperation rates to those of patients who receive a CCK implant. The investigators hypothesize that patients who receive an RHK implant will have similar loosening rates and clinical outcomes compared to patients who receive a CCK implant. Lastly, knee stability and patient satisfaction may improve with the use of a rotating hinge device.
Medstar Health Research Institute is the lead sponsor of 161 studies on the registry; 31 are open to participants now.
Of its 14 completed or terminated interventional studies of FDA-regulated products, 7 (50%) have results posted.
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Exclusion:
Patients in this arm will receive a condylar constrained implant.
Device: Condylar Constrained knee system. ( NexGen Legacy Condylar Constrained Knee by Zimmer Biomet)
Patients in this arm will receive a rotating hinge knee implant.
Device: Rotating Hinge Knee ( NexGen Rotating Hinge Knee by Zimmer Biomet)
Patients in this group will receive a condylar constrained knee implant at the time of surgery and will have their outcomes with this implant assessed over 10 years.
Patients in this group will receive a rotating hinge knee implant and will be followed for the next 10 years to asses outcomes.
Reoperation Rate
The primary outcome is any reoperation on the ipsilateral knee.
Time frame: From time of surgery to end of study. Investigators will plan to assess for reoperation at routine standard of care visits at the following time points: 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years
KOOS JR score
Patient reported outcomes including KOOS JR score. It is a score that ranges from 0-100, where 0 indicates total knee disability and 100 indicates perfect knee health.
Time frame: From time of surgery to end of study. Investigators will obtain patient reported outcomes at routine standard of care visits at the following time points: preop visit and then 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years.
Aseptic Loosening
Aseptic loosening is verified through radiographic images.
Time frame: Investigators will plan to assess for Aseptic loosening at routine standard of care visits at the following time points: 6 weeks postoperatively, 6 months, 1 year, and then yearly thereafter for 8 years through radiographs
Range of motion
Range of motion at the knee joint will be assessed : flexion, extension, varus and valgus motion will be assessed.
Time frame: Investigators will plan to assess range of motion at routine standard of care clinic visits at the following time points: 6 weeks postoperatively, 6 months, 1 year, and then yearly after for 8 years
Knee society score (KSS)
Patient reported outcomes include knee society score (KSS). There is a knee score and functional score, both scored 0-100 with 0 indicating worse knee conditions and 100 indicating good knee conditions.
Time frame: From time of surgery to end of study. Investigators will plan to assess for PROMs at routine standard of care visits at the following time points: pre-op visit, 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years
PROMIS score
A patient reported outcome survey assessing the patient's perspective on their overall health and quality of life. PROMIS assessments are scored on a T-score metric. High scores mean more of the concept being measured. 10 points on the T-score metric is one standard deviation (SD). PROMIS scores have a mean of 50 and standard deviation (SD) of 10 in a referent population. The referent population is usually the US General Population. A score of 40 is one SD lower than the mean of the reference population. A score of 60 is one SD higher than the mean of the reference population. Interpretation Scores 0.5 - 1.0 SD worse than the mean = mild symptoms/impairment Scores 1.0 - 2.0 SD worse than the mean = moderate symptoms/impairment Scores 2.0 SD or more worse than the mean = severe symptoms/impairment
Time frame: From time of surgery to end of study. Investigators will obtain patient reported outcomes at routine standard of care visits at the following time points: preop visit and then 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years.
UCLA Activity Score
Patient reported outcome survey which is a 10-point rating scale used to measure a patient's physical activity level. Scale ranges from 1 (wholly inactive and dependent) to 10 (regular participation in impact sports).
Time frame: From time of surgery to end of study. Investigators will obtain patient reported outcomes at routine standard of care visits at the following time points: preop visit and then 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years.
EQ5D score
Patient reported survey that assesses mobility, pain, mental health, quality of life. A total score closer to 0 indicates poor health where a score closer to 1 indicates good health.
Time frame: From time of surgery to end of study. Investigators will obtain patient reported outcomes at routine standard of care visits at the following time points: preop visit and then 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years.
SANE score
A patient reported survey is a single-question rating scale from 0 to 100 where a patient grades their current knee function as a percentage of normal with 100 indicating that their knee is completely normal.
Time frame: From time of surgery to end of study. Investigators will obtain patient reported outcomes at routine standard of care visits at the following time points: preop visit and then 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years.
Radiographic assessment of fixation
An x-ray will be done to assess that the implant is in the correct position.
Time frame: From time of surgery to end of study. Investigators will plan to assess for fixation at routine standard of care visits at the following time points: 6 weeks postoperatively, 6 months, 1 year, and then annually for 8 years.
Any other surgical complications
The investigators plan to assess for any other surgical outcomes including but not limited to implant wear, prosthetic joint infection, periprosthetic fracture, arthrofibrosis, and instability.
Time frame: Investigators will plan to assess for complications at routine standard of care visits at the following time points: 2 weeks postoperatively, 6 weeks postoperatively, 6 months, 1 year, and then yearly after for 8 years
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Started Feb 2026 (actual). Primary completion is estimated for Jan 2037, 131 months after the start.
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