Two-stage Exchange Arthroplasty for Infected Total Knee Arthroplasty: Predictors of Failure.

Clin Orthop Relat Res. 2011 Nov;469(11):3049-54.
Mortazavi SM, Vegari D, Ho A, Zmistowski B, Parvizi J.

Source

The Rothman Institute of Orthopaedics at Thomas Jefferson University Hospital, 925 Chestnut Street, 5th Floor, Philadelphia, PA, 19107, USA.

Abstract

BACKGROUND:

In North America, a two-stage exchange arthroplasty remains the preferred surgical treatment for chronic periprosthetic joint infection (PJI). Currently, there are no proper indicators that can guide orthopaedic surgeons in patient selection for two-stage exchange or the appropriate conditions in which to reimplant.

QUESTIONS/PURPOSES:

To identify (1) the rate of recurrent PJI after two-stage exchange and (2) the role of 15 presurgical and 11 operative factors in influencing the outcome of two-stage revision.

PATIENTS AND METHODS:

From a prospective database we identified 117 patients who had undergone two-stage exchange arthroplasty for PJI of the knee from 1997 to 2007. Failure of two-stage revision was defined as any treated knee requiring further treatment for PJI. We identified 15 presurgical and 11 surgical factors that might be related to failure. Minimum followup was 2 years (average, 3.4 years; range, 2-9.4 years).

RESULTS:

Thirty-three of 117 reimplantations (28%) required reoperation for infection. Age, gender, body mass index, and comorbidity indices were similar in both groups. Multivariate analysis provided culture-negative (odds ratio [OR], 4.5; 95% confidence interval [CI], 1.3-15.7), methicillin-resistant organisms (OR, 2.8; 95% CI, 0.8-10.3), and increased reimplantation operative time (OR, 1.01; 95% CI, 1.0-1.03) as predictors of failure. ESR and CRP values at the time of reimplantation and time from resection to reimplantation were not predictors.

CONCLUSIONS:

Our observations suggest the failure rate after two-stage reimplantation for infected TKA is relatively high. Culture-negative or methicillin-resistant PJI increases the risk of failure over four- and twofold, respectively. We identified no variables that would guide the surgeon in identifying acceptable circumstances in which to perform the second stage.

LEVEL OF EVIDENCE:

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

IORG Arthroplasty update

Alignment of Computer-Assisted Total Knee Arthroplasty in Patients With Altered Hip Center

J Arthroplasty. 2011 Oct;26(7):1072-7.

Mullaji AB, Lingaraju AP, Shetty GM.

This study aimed to determine limb and component alignment after computer-assisted total knee arthroplasty in 30 patients (32 limbs) with an altered hip center due to a prior hip implant or deformed femoral head. There were no outliers greater than ±3° in the postoperative coronal alignment of the limb and the femoral component in relation to the altered hip center. Two limbs
(8%) were more than ±3° for coronal alignment of the femoral component in relation to the anatomical hip center and 96% of limbs had less than 2° deviation in relation to the altered hip center. 
Computer-navigated total knee arthroplasty results in accurate restoration of lower limb and component alignment in patients with prior hip implants or deformed femoral heads where accurate restoration of alignment may be challenging due to altered hip center.

IORG Arthroplasty Update