Investigators see comparable results with conventional and navigated TKA

Issue: April 2013

Researchers from Korea found similar results between the knees of patients who underwent conventional total knee arthroplasty in one limb and computer navigation arthroplasty in the other.

“Our data demonstrated there was no difference in clinical function, alignment and survivorship of the components between the computer-navigated and conventional total knee arthroplasties,” Young-Hoo Kim, MD, from Total Joint Replacement Center at Ewha Woman’s University School of Medicine, in Seoul, Korea, told Orthopaedics Today Europe.

The right total knee arthroplasty (TKA) was performed conventionally. The left TKA was done using navigation in the same patient. Both knees have the PFC Sigma rotating platform prosthesis (DePuy; Warsaw, Ind., USA).

Kim and colleagues assessed 520 patients in a single-surgeon series. The group, which included 452 women, was aged 68 years, mean. A PFC Sigma prosthesis (DePuy; Warsaw, Ind., USA) was implanted in 400 knees and 640 knees received the NexGen LPS-Flex design (Zimmer; Warsaw, Ind., USA). Both implants used all-polyethylene patellar components. The VectorVision CT-free knee system (BrainLAB; Munich, Germany) was used for the computer-assisted navigated surgeries, based on the study.

Patients had radiographs done preoperatively, at 3 months postoperatively and annually for 10 years to 12 years. They were also evaluated at the same time points with Knee Society and WOMAC scores, according to the abstract. The patients had CT scans at their latest follow-up.

A TKA the investigators performed using computer navigation is shown.

No difference in survivorship

The investigators found implant revision occurred in six total knee arthroplasties (TKAs) in the NexGen LPS-Flex group for aseptic loosening (ASL) of the femoral component. These included four computer-navigated and two conventional TKAs. Four knees in the PFC Sigma group were revised for ASL of the tibial component, which occurred in two computer-navigated and two conventional TKAs each.

At 10.8 years, Kaplan-Meier implant survivorship was 99.2% for conventional and 98.8% for computer-navigated knees, according to the study abstract. However, the differences between the groups for knee function, motion, activity and pain were not statistically significant. WOMAC and Knee Society Scores were comparable.

Longer operative, tourniquet times

Kim and colleagues found incision length, intraoperative blood loss, transfusion volume and the duration and volume of the drainage were not significantly different between the computer-navigated and conventional knees. However, they found a significantly longer mean operative time for computer-navigated cases. Tourniquet time in that group was also longer, according to the study abstract.

The researchers did not perform side-to-side comparisons of individual patients to determine whether computer-navigated TKA offered surgeons better feedback when the TKAs were performed consecutively.

“We plan to follow up these patients continuously to determine the effect of computer-navigated TKA compared with conventional TKA on long-term implant survival,” Kim said. – by Jeff Craven

Reference:

Kim Y-H. J Bone Joint Surg Am. 2012;doi:10.2106/JBJS.L.00142.

Young-Hoo Kim, MD, can be reached at MokDong Hospital, 911-1, MokDong, YangChun-Ku, Seoul, Korea; email: younghookim@ewha.ac.kr.

Disclosure: The authors have no relevant financial disclosures.