Similar complication rate between simultaneous, staged bilateral TKA

Simultaneous bilateral TKA may be more cost effective than staged procedures. But debate continues over rehabilitation costs.

Although bilateral total knee arthroplasty patients have more complications than unilateral TKA patients, simultaneous bilateral TKA produces complication rates similar to staged procedures, Australian researchers found.

“There was no difference among the groups in our study regarding cardiovascular complications. There was a higher rate of asymptomatic deep vein thrombosis in the bilateral groups compared with the unilateral group, but no difference between the simultaneous or staged groups,” the authors said in the study.

“It should be noted that due to the sensitivity of Doppler ultrasound, pelvic vein thrombosis may have been missed. However, the rate of pulmonary embolism did not differ between the bilateral groups. Additionally, there was no difference in perioperative mortality among the groups or in the rates of mortality during the follow-up period,” they said.

Simultaneous vs staged bilateral TKA

Mervyn J. Cross, MD, FRACS, and colleagues at the Australian Institute of Musculoskeletal Research in Sydney, compared the results of simultaneous and staged bilateral uncemented TKA to those of unilateral TKA. The study included 1867 knees among 1304 patients treated between 1992 and 2003, primarily for knee osteoarthritis. Of these, 438 patients underwent simultaneous bilateral TKA, 125 underwent staged bilateral TKA and 741 underwent unilateral TKA, according to the study.

Significantly more men underwent simultaneous procedures, while significantly more women underwent unilateral or staged bilateral procedures (P<.01). Also, patients’ ages varied between groups, averaging 65 years among staged bilateral patients and 68 years among unilateral patients, the authors noted.

Surgeons implanted the Active TKR system (Australian Surgical Design and Manufacture) in all patients using a standard surgical procedure. Simultaneous and unilateral patients had similar mean durations of follow-up of 75 to 76 months. Follow-up varied slightly among staged bilateral TKA patients, averaging 90 months for the first knee and 57 months for the second knee, with an average of 34 months between procedures.

The researchers found that simultaneous and staged bilateral TKA patients had a significantly higher complication rate compared to unilateral TKA patients (P<.001). However, complication rates did not significantly differ between the two bilateral TKA groups.

The simultaneous bilateral TKA group experienced 77 cases (17.6%) of thrombosis compared with 21 cases (15.2%) in the staged bilateral group. Unilateral TKA patients experienced 82 cases (11.1%) of thrombosis (P<.001), according to the study.

Both bilateral TKA groups also had higher incidences of pulmonary emboli compared to the unilateral TKA group, but there was no difference between the two bilateral groups.

All three groups had a similar incidence of cardiac complications and rates of deep infection. Overall, surgeons performed 13 revision procedures: six simultaneous bilateral, one staged bilateral and six unilateral. One patient in each bilateral group also died from myocardial infarction.

At five years’ follow-up, all three groups had significant improvements in mean Knee Society Clinical Rating scores, as follows:

simultaneous bilateral improved from 96 at preop to 184 at five years;
staged bilateral improved from 93 at preop to 186 at five years; and
unilateral improved from 98 at preop to 181 at five years.

Potential cost savings

Performing simultaneous bilateral TKA may have potential economic and logistical benefits over staged procedures, the authors noted.

“Only one anesthetic is required with a reduction in operating time. The length of hospital stay has been consistently shown to be the same for [unilateral] and bilateral procedures. Physiotherapy and discharge coordination arise only once,” they said, adding that in Australia, the patient’s out-of-pocket expenses are lower than with staged procedures.

However, debate remains over the actual financial savings when factoring in the costs of rehabilitation, they noted.

Despite this, the authors support performing simultaneous bilateral TKA and “feel that it is a safe, successful and cost-effective strategy for the treatment of bilateral arthritis of the knee,” they said.

For more information:

Hutchinson JRM, Parish EN, Cross MJ. A comparison of bilateral uncemented total knee arthroplasty. J Bone Joint Surg Br. 2006;88-B:40-43.