Swelling assessment after total knee arthroplasty.

BACKGROUND: Total knee arthroplasty is a commonly performed elective orthopaedic surgery. Patients may endure substantial knee swelling following surgery, which are attributable to both effusion and edema. Studies have been aiming to identify an accurate and reliable method to quantify post-operative knee swelling to aid monitoring progress and treatment. The aim of this article was to review the means of clinically applicable measurements for knee swelling post TKA. METHODS: The medical literature was searched using PubMed to search for articles published using the terms knee edema, effusion, swelling, knee arthroplasty, knee replacement, total knee arthroplasty, total knee replacement, TKA, TKR. Year of publication was not restricted. Only English language publications were included. Only full-text published articles from peer-reviewed journals were eligible for inclusion. The knee swelling measurement methods used in post TKA were reviewed. RESULTS: Advancement in bioimpedance spectroscopy and handheld 3D scanning technology allows quick and precise quantification of knee swelling volume that the traditional clinical circumferential measurement and volumetric measurement lack. Handheld 3D scanning is also a potential tool to estimate the change of knee effusion volume and muscular volume after the surgery. Magnetic resonance imaging is accurate in effusion measurement but also the most time and resource demanding method. CONCLUSION: Bioimpedance spectroscopy and 3D scanning technology can be the future tools for clinically measurement of knee swelling after total knee arthroplasty.

Interobserver and intraobserver error in distal femur transepicondylar axis measurement with computed tomography.

On 2 separate occasions at least 1 week apart, 6 independent observers studied errors in identification of the transepicondylar axis (TEA) using computed tomography in 10 cadaveric knees. The reference surgical TEA was established by dissection of specimens. We found an average error of 2.6 degrees (external rotation) when the TEA was identified by computed tomography. The error was significantly smaller when the TEA was identified by using a conventional axial image than when a 3-dimensional reconstruction image was used (P < .001, paired t test). No significant intraobserver error (P = .814, Wilcoxon rank test) was found when the measurement was performed using conventional 2-dimensional computed tomography images. However, significant interobserver difference was evident (P < .001, Friedman test).