Large osteophyte removal from the posterior femoral condyle significantly improves extension at the time of surgery in a total knee arthroplasty

Murilo Anderson Leie; Antonio Klasan; Takeshi Oshima; Sven Edwards Putnis; Wai Weng Yeo; Lincoln Luk; Myles Coolican

doi:10.1016/j.jor.2019.10.021

Large osteophyte removal from the posterior femoral condyle significantly improves extension at the time of surgery in a total knee arthroplasty

J Orthop. 2019 Nov 18:19:76-83. doi: 10.1016/j.jor.2019.10.021. eCollection 2020 May-Jun.

Authors

Murilo Anderson Leie¹, Antonio Klasan^{1

2}, Takeshi Oshima¹, Sven Edwards Putnis¹, Wai Weng Yeo³, Lincoln Luk⁴, Myles Coolican¹

Affiliations

¹ Sydney Orthopaedic Research Institute, Level 1 The Gallery, 445 Victoria Avenue, Chatswood, New South Wales, 2067, Australia.
² University Hospital Marburg, Center for Orthopedics and Traumatology, Baldingerstrasse, 35043, Marburg, Germany.
³ University of New South Wales Medicine, Wallace Wurth Building, 18 High St, Kensington, New South Wales, 2052, Australia.
⁴ Royal Perth Hospital, Perth, Western Australia, 6060, Australia.

Abstract

Removing osteophytes from the posterior compartment of the femur eliminates the tenting effects on the joint capsule and consequently increases the extension gap in total knee arthroplasty. However, there is no clear association with the size of osteophytes removed and the potential degree of additional extension achieved at time of surgery.

Aims: Correlate the size of posterior osteophytes removed with the degree of extension gained intraoperatively in total knee arthroplasty and develop a radiological classification system to grade these osteophytes.

Methods: Patients who underwent a TKA had pre and post operative sagittal radiographs assessed and classified according to 4 different categories of a proposed classification system. Knee extension was then assessed by a computer navigated system before incision and after implant insertion. Confounding factors were controlled and considered on the analysis. The study was done retrospectively.

Results: 147 patients were included in the study. Ninety-three (63.2%) patients had osteophytes on the posterior aspect of the femur completely removed and fifty-four patients (36.8%) did not have radiological evidence of osteophytes on the posterior aspect of the femur. There was a positive and linear correlation (Pearson correlation 0.327, p .005) between osteophyte size and degree of extension corrected at time of surgery. On Multivariate Logistic Regression Analysis, we found that small osteophytes (Grade 1) did not seem to affect the extension, while removing Grade 2 or Grade 3 osteophytes lead to a gain in extension of 2.7 and 4.5° respectively.

Conclusion: Removing large osteophytes (Grade 2 and Grade 3) from the posterior femoral compartment can be used as an adjuvant strategy to ensure that intraoperative extension is optimal. However removing small osteophytes (Grade 1) should not be expected to affect extension at the time of surgery in TKA and could increase intra-operative time and morbidity.

Keywords: Extension; Flexion contracture; Osteophyte removal; Posterior osteophyte; Range of movement; Total knee replacement.