Abstract
Background:
Patellectomized knees perform poorly with respect to extensor mechanism function and anterior knee pain. The clinical outcome after total knee arthroplasty (TKA) in this group of patients is inferior to patients with a patella independent of resurfacing.
Purpose:
To evaluate clinical long-term outcome, isokinetic strength and radiographic appearance of a neo-patella in TKA, which was reconstructed using autologous bonegraft.
Materials and Methods:
In the period of 1990 to 1995, nine previously patellectomized patients with a mean age of 55 years (range: 38 to 67) underwent cementless Low-Contact-Stress TKA for osteoathritis of the tibio-femoral joint. One patient deceased 5 years post surgery. Mean follow-up was 8. 0 years (range: 6 to 12) The autograft was taken in five cases from the iliac crest, in two cases from the posterior femoral condyle and in another two cases from the opposite patella at time of simultaneous bilateral TKA surgery. Evaluation included clinical investigation, specific patella score, radiographic analysis and isokinetic strength measurement at 60 degrees per second (Biodex).
Results:
Clinical scores had a mean of 27 out of 30 points (range: 19 to 30) and mean isokinetic strength of knee extension reached 71Nm (81%) compared with the opposite site. One patient with bilateral patellectomy and unilateral TKA showed an increase of 50 % strength (51Nm versus 77Nm) in the kne with TKA and neo-patella. Radiographs in three planes showed minor signs of neo-patella bone resorption in three cases, but evidence of retrabeculation and bone remodelling in all neo-patellae.
Conclusions:
Reconstruction of a neo-patella in TKA using autograft provides near to normal isokinetic strength, no evidence of considerable autograft resorption, excellent or good clinical outcome and high patients satisfaction after a mean of 8 years. The study provides encouraging data for reconstructing a neo-patella in TKA with autograft.
Address for correspondence: jgboldt@hotmail.com
Schulthess Klinik, Zurich, Switzerland.
