Abstract
Purpose
The patella provides a mechanical advantage to the knee extensor mechanism. Patellectomy, performed for trauma or patellofemoral arthrosis, does not preclude the development of tibiofemoral arthrosis. Total knee arthroplasty is the mainstay of treatment for tibiofemoral arthrosis. The purpose of this study was to evaluate the outcomes of total knee arthoplasty in patients who previously underwent patellectomy.
Method
A retrospective analysis was completed on a prospectively collected database to identify all patients who underwent total knee arthroplasty following a previous patellectomy. Sixty-one total knee arthroplasties in 57 patients were identified. Patient demographics as well as functional outcome scores, including WOMAC and Knee Society Scores, were evaluated.
Results
Thirty-six females (63.2%) and 21 males (36.8%) underwent a Total knee arthroplasty between July 1984 and April 2010. Mean follow up was 6.0 years (3 months–20 years). Mean Age and BMI was 59.8 8.6 and 30.5 5.8 respectively. Patellectomy was performed for trauma (56) and patellofemoral arthosis (five). All polyethylene inserts were cruciate substituting. There were five deaths and 10 knees (16.4%) required revision surgery. Causes for failure included aseptic loosening (2), polyethylene wear (3), component fracture (2), infection (2) and stiffness (1). WOMAC scores improved from 38.0 14.1 pre-operatively to 58.5 22.1 at latest review. Knee Society scores improved from 81.5 31.2 to 136.0 41.0. Range of motion and extensor lag changed preoperatively from 105.7 15.9 and 4.3 15.5 degrees to 110.7 12.1 and 6.3 7.1 degrees postoperatively.
Conclusion
Despite the mechanical disadvantage to the knee extensor mechanism rendered by patellectomy, total knee arthroplasty is an effective treatment option for tibiofemoral arthrosis in these patients.
