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Total knee arthroplasty following patellectomy.
D W Lennox1, D S Hungerford, K A Krackow
1Union Memorial Hospital, Baltimore, MD 21218.
Clinical Orthopaedics and Related Research
|October 1, 1987
Summary
Total knee arthroplasty (TKA) after patellectomy yields poorer outcomes. Patients without patellae had significantly diminished strength and fewer good to excellent results compared to controls, suggesting alternative treatments may be better.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Rehabilitative Medicine
Background:
- Patellectomy, the surgical removal of the kneecap, is a procedure that can precede total knee arthroplasty (TKA).
- The functional impact of a prior patellectomy on the success of subsequent TKA is not fully understood.
- Assessing outcomes in patients with a history of patellectomy is crucial for surgical decision-making.
Purpose of the Study:
- To evaluate the outcomes of primary total knee arthroplasty (TKA) in patients who have previously undergone a patellectomy.
- To compare the functional results and strength of TKA patients with a history of patellectomy to a control group with intact patellae.
- To identify prognostic factors associated with successful TKA in the patellectomy patient cohort.
Main Methods:
- Chart reviews, clinical examinations, and radiographic evaluations were performed on eleven patients with prior patellectomy undergoing TKA.
- Knee arthroplasty outcomes were rated on a standard scale.
- Quadriceps and hamstring torque were quantified using an isokinetic dynamometer at a testing speed of 30 degrees/second.
Main Results:
- Only five out of eleven knees with prior patellectomy achieved good to excellent results, contrasting with all eleven control knees.
- Patients with previous patellectomy demonstrated diminished quadriceps and hamstring torque and strength compared to controls.
- Favorable prognostic factors for TKA success included fewer than three prior knee operations, absence of severe radiographic arthritis, and quadriceps strength exceeding 40 ft-lb.
Conclusions:
- Total knee arthroplasty (TKA) in patients with a history of patellectomy is associated with significantly poorer outcomes and reduced muscular strength.
- Prognostic factors such as the number of previous surgeries, severity of arthritis, and quadriceps strength are critical in predicting TKA success post-patellectomy.
- For patients without patellae lacking favorable prognostic factors, bracing or primary arthrodesis should be strongly considered over TKA.