One-peg versus three-peg patella component fixation in total knee arthroplasty

In many designs of total knee arthroplasty, the patella with one central pe g has been replaced by a patella with three small pegs for cement fixation. There have been recent reports of failure of this design. This is a prospe ctive, consecutive study of two types of patella component fixation in 228 posterior-stabilized knee arthroplasties done by one surgeon. A central peg all-polyethylene component was used for 84 consecutive knees in 63 patient s (Group A) and a three-peg patella was used for the next 144 consecutive k nees in 99 patients (Group B). The mean followup was 6.7 years (range, 2-10 years) for Group A and 3.5 years (range, 2-6 years) for Group B. Except fo r the patellar component fixation, all knees had the same posterior-stabili zed prosthesis using a specific protocol for patellar resurfacing. No patie nt required reoperation for a patellofemoral complication. The prevalence o f patella fracture was higher in Group A, 4.7% (four knees), compared with 2.1% (three knees) in Group B, but this difference was not statistically si gnificant. The presence of anterior knee pain referable to the patella was 7.1% (five patients, six knees) in Group A (one patient with two knees had severe anterior knee pain) and 9% (13 knees in 13 patients) in Group B. The re was no patella clunk syndrome, subluxation, or fracture of a fixation pe g in either group. With this specific protocol for patella resurfacing, the re was a higher rate of complications with the one central peg patella (4.7 %) than with the three-peg patella (2.1%), but this did not reach statistic al significance. The results do not support an increased risk of component failure with this three-peg patella design, but do not, at this length of f ollowup, show any significant advantage of three-peg fixation.