Abstract
Objective
We performed total knee arthroplasty (TKA) without patella resurfacing in patients with osteoarthritis (OA) of the knee.
The purpose of the present study was to evaluate the clinical results and the appropriateness TKA without patella resurfacing.
Methods
A total of 61 patients (61 affected knees) who had undergone a Low Contact Stress mobile − bearing knee arthroplasty (LCS− TKA) (Depuy, Warsaw, IN. USA) 10 years or more before the present study were enrolled. The LCS− TKAs did not include patella resurfacing. The patients' mean age was 77.7 ± 6.1 years (range: 59−94 years). The mean follow-up period was 121 ± 2.4 months (range: 120−129 months). The clinical evaluation used the scoring system for OA of the knees issued by the Japanese Orthopaedic Association (JOA score). We defined patellofemoral (PF) pain, crepitation, patellar clunk syndrome, spin-out, and reoperation as complications. We also used X-Ray imaging to measure the component angle, patella height, lateral shift ratio, tilting angle, femorotibial angle, posterior condylar offset and joint line, and evaluated the localization of sclerotic changes in the patella.
All of the LCS− TKAs were performed by one surgeon using the midvastus approach. During the operation, the osteophyte around the patella was resected, and the osteophyte on the articular surface was shaped using a bone saw.
For statistical analysis we performed Mann-Whitney's U test and adopted a significance level of P<5%.
Results
The average JOA score improved significantly from 46.2 ± 10.4 before the LCS− TKA to 82.6 ± 6.1 after the LCS− TKAs (P = 0.0002).
No cases of patellar clunk syndrome or spin-out
occurred. Revision surgery was performed for two cases, one involved an infection, and the other involved a patella fracture.
Postoperative PF pain was found in 6 patients (6 affected knees) at the final evaluation. However, in these patients, the pain was less severe than it had been preoperatively, and revision surgery for PF pain was needed or performed.
The postoperative radiological evaluation was favorable on the whole. The localization of sclerotic changes in the patella on X-ray were in 32 cases around tip of the patella, on the other no remarkable change were in 29 cases.
Conclusion
The clinical and radiological evaluations of the patella non−resurfacing mobile bearing total knee arthroplasty was favorable overall. Treatment of the patella in total knee arthroplasty remains controversial.
We suggest that the patella in LCS−TKAs does not always need to be resurfaced.
