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Experimental study of risk of medial hinge fracture during distal femoral varus osteotomy

Authors :
Thomas Mereb
Henri Favreau
Matthieu Ollivier
Hamdi Jmal
François Bonnomet
Nadia Bahlouli
Pierre Martz
Matthieu Ehlinger
Source :
Orthopaedicstraumatology, surgeryresearch : OTSR.
Publication Year :
2022

Abstract

Lateral opening wedge distal femoral osteotomy (LOWDFO) is indicated for isolated lateral osteoarthritis in the valgus morphotype. Medial hinge fracture is a factor for poor prognosis. The present study had two aims: 1) to assess the impact of a temporary K-wire on hinge fracture risk; and 2) to assess the impact of LOWDFO opening speed.The main study hypothesis was that a temporary hinge K-wire reduces hinge fracture risk. The second hypothesis was that faster opening speed increases fracture risk.Twenty femurs were produced by 3D printing from a CT database, reproducing LOWDFO anatomy. The ABS® polymer showed the same breaking-point behavior as human bone. Ten specimens were included in the "K-wire" group (KW+) and 10 in the "No K-wire" group (KW-). To determine high and low speed, a motion-capture glove was used by 2 operators, providing 3D modeling of the surgeon's hand. High speed was defined as 152mm/min and low speed as 38mm/min. The KW+ and KW- groups were subdivided into high- and low-speed subgroups (HS, LS) of 5 each. Compression tests were conducted using an Instron® mechanical test machine up to hinge fracture. The main endpoint was maximum breaking-point force (N); the secondary endpoints were maximum displacement (mm) and maximum speed (min) at breaking point.The K-wire significantly increased maximum breaking-point force (LS, 143.08N vs. 93.71N, p0.01; and HS, 186.98N vs. 95.22N, p0.01), but not maximum displacement (LS, 26.17mm vs 24.11mm, p= 0.31; and HS 26.18mm vs. 23.66mm, p=0.14) or maximum time (LS, 27.07sec vs. 24.94sec, p=0.31; and HS, 5.24sec vs. 4.73sec, p=0.14). Speed did not affect maximum force (KW+, 143.08N vs. 186.98N, p= 0.06; and KW-, 93.71N vs. 95.22N, p=0.42) or maximum displacement (KW+, 26.17mm vs. 26.18mm, p=1; and KW-, 24.11mm vs. 23.66mm, p=0.69). Only maximum time was greater at low speed (KW+, 27.07sec vs. 5.24sec, p0.01; and KW-, 24.94sec vs. 4.73sec, p0.01), which is obvious for constant distance.The first study hypothesis was confirmed, with significantly lower hinge fracture risk with the K-wire, independently of opening speed. The second hypothesis was not confirmed. The study was performed under strict experimental conditions, unprecedented to our knowledge in the literature. However, complementary clinical studies are needed to confirm the present findings.IV, experimental study.

Details

ISSN :
18770568
Database :
OpenAIRE
Journal :
Orthopaedicstraumatology, surgeryresearch : OTSR
Accession number :
edsair.doi.dedup.....24c69bff7ab4a2f83c7c79dbf8589f22