Revision surgery for patellar dislocation after primary total knee arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Reconstructive Surgery

Background:

• Patellar dislocation is a potential complication following primary total knee arthroplasty (TKA).
• Understanding risk factors and functional outcomes after revision surgery for patellar dislocation is crucial for improving patient care.
• Revision TKA aims to address mechanical failures and restore function.

Purpose of the Study:

• To identify risk factors associated with patellar dislocation after primary TKA.
• To evaluate the functional outcomes of patients undergoing revision surgery for patellar dislocation.
• To determine the effectiveness of revision techniques in improving patellar tracking and patient function.

Main Methods:

• Retrospective evaluation of 39 knees in 39 patients who underwent revision surgery for patellar dislocation.
• Patients averaged 68 years old at revision and were followed for a mean of 3.2 years.
• Assessment included Knee Society and Function scores, range of motion, and analysis of surgical technique errors.

Main Results:

• Mean Knee Society and Function scores significantly improved post-revision (from 34 to 77 and 35 to 54, respectively).
• Common causes of dislocation included technical errors: soft-tissue imbalance and malaligned components leading to poor patellar tracking.
• Patellar tracking improved with soft-tissue realignment and revision of malaligned/loose components.

Conclusions:

• Revision surgery can significantly improve knee function and scores after patellar dislocation in TKA.
• Technical errors in primary TKA are key risk factors for patellar dislocation.
• Despite improvements, a significant proportion (two-thirds) of patients experience residual disabilities and pain after revision surgery.