Total knee replacement: should it be cemented or hybrid?

OBJECTIVE

To compare the complication rates associated with total knee arthroplasty against the types of fixation (hybrid or cemented), using a single total knee design (the anatomic modular knee [AMK] prosthesis).

DESIGN

A prospective, nonrandomized, controlled trial.

SETTING

University Hospital in London, Ont., a tertiary care teaching centre.

PATIENTS

Two groups made up of 484 knees in 395 patients (89 bilateral).

INTERVENTIONS

In 260 knees a hybrid configuration (cemented tibia and noncemented femur) was used (group 1). In 224 knees the femoral and tibial components were cemented (group 2). All patellae were cemented in both groups.

MAIN OUTCOME MEASURES

Clinical results were assessed by The Knee Society Clinical Rating Scores at 3 months, 6 months and yearly intervals. Radiographic results were determined by 3-foot standing radiographs and at each follow-up visit standing knee radiographs, lateral and skyline views. Radiographs were analysed for alignment, presence or absence of radiolucent lines or changes in the position of the implant. All reoperations and nonoperative complications were recorded.

RESULTS

At an average follow-up of 4.8 years, 8 knees (1.6%) required reoperation. An analysis of the complications leading to reoperation demonstrated no difference between the 2 groups.

CONCLUSIONS

There was no difference in outcome whether the femoral component was cemented or not. Medium-term results of the AMK are excellent with a very low reoperation rate.