Long-term followup after mobile-bearing total knee replacement

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Clinical Outcomes Research

Background:

• Total knee replacement (TKR) is a common procedure for end-stage knee osteoarthritis.
• Assessing long-term survivorship and clinical outcomes of cementless TKR designs is crucial for surgical decision-making.
• The New Jersey LCS (Low Contact Stress) system includes both meniscal-bearing posterior cruciate-retaining and rotating-platform designs.

Purpose of the Study:

• To evaluate the clinical results, radiographic findings, and survivorship of cementless posterior cruciate-retaining meniscal-bearing and rotating-platform LCS total knee replacements.
• To compare the long-term performance of these two cementless TKR designs over a 10 to 20-year follow-up period.

Main Methods:

• A retrospective analysis of 309 initial cementless New Jersey LCS total knee replacements (309 posterior cruciate-retaining meniscal-bearing and rotating-platform).
• Clinical assessments using a strict knee scoring scale and radiographic analyses were performed at 10 to 20 years (mean 12.4 years).
• Survivorship analysis was conducted using endpoints of mechanical revision and poor clinical knee scores.

Main Results:

• Good to excellent clinical results were achieved in 97.9% for both posterior cruciate-retaining and rotating-platform prostheses.
• Radiographic analysis showed stable component fixation in most cases, with minimal gross migration.
• Significant osteolysis requiring revision occurred in 1.8% of rotating-platform cases with prior surgeries; patellar wear was noted in one case with prior surgery.

Conclusions:

• Cementless posterior cruciate-retaining meniscal-bearing and rotating-platform LCS total knee replacements demonstrate comparable long-term clinical outcomes and survivorship.
• Both designs offer reliable fixation and good functional results, though careful consideration of prior surgical history is warranted for rotating-platform components.
• These findings support the long-term efficacy of these cementless TKR designs in appropriate patient populations.