Paul Borbas1, Maximilian Vetter2, Rafael Loucas2, Simon Hofstede3, Karl Wieser2, Lukas Ernstbrunner2. 1. Department of Orthopedics, Balgrist University Hospital, Zürich, Switzerland. Electronic address: paul.borbas@balgrist.ch. 2. Department of Orthopedics, Balgrist University Hospital, Zürich, Switzerland. 3. Institute of Biomechanics, Eidgenössische Technische Hochschule Zürich (ETH Zürich), Zürich, Switzerland.
Abstract
BACKGROUND: Coronal shear fractures of the capitellum are rare, and their surgical management is challenging, without a defined gold standard. The purpose of this study was to compare the biomechanical stability of 3 different internal fixation techniques for simple coronal shear fractures of the capitellum without posterior comminution. METHODS: Dubberley type IA fractures of the capitellum were created in 18 cadaveric elbows, which were age and sex matched to the following 3 internal fixation groups: (1) two anteroposterior cannulated headless compression screws (HCSs), (2) two anteroposterior HCSs with an additional anterior antiglide plate (antiGP), and (3) a posterolateral distal humeral locking plate (LP). All fixation techniques were cyclically loaded with 75 N over 2000 cycles and ultimately until construct failure. Data were analyzed for displacement, construct stiffness, and ultimate load to failure. RESULTS: Fragment displacement under cyclic loading with 2000 cycles did not show a significant difference (P = .886) between the 3 groups. The HCS group showed the highest stiffness compared with the HCS-antiGP and LP groups (602 N/mm vs. 540 N/mm vs. 462 N/mm, P = .417), without reaching a statistically significant difference. Ultimate load to failure was also not significantly different on comparison of all 3 groups (P = .297). CONCLUSIONS: Simple coronal shear fractures of the capitellum are biomechanically equally stabilized by HCSs compared with HCSs with an additional antiGP or a posterolateral distal humeral LP. In view of the advantages of less (invasive) metalware, the clinical use of 2 isolated anteroposterior HCSs appears reasonable.
BACKGROUND: Coronal shear fractures of the capitellum are rare, and their surgical management is challenging, without a defined gold standard. The purpose of this study was to compare the biomechanical stability of 3 different internal fixation techniques for simple coronal shear fractures of the capitellum without posterior comminution. METHODS: Dubberley type IA fractures of the capitellum were created in 18 cadaveric elbows, which were age and sex matched to the following 3 internal fixation groups: (1) two anteroposterior cannulated headless compression screws (HCSs), (2) two anteroposterior HCSs with an additional anterior antiglide plate (antiGP), and (3) a posterolateral distal humeral locking plate (LP). All fixation techniques were cyclically loaded with 75 N over 2000 cycles and ultimately until construct failure. Data were analyzed for displacement, construct stiffness, and ultimate load to failure. RESULTS: Fragment displacement under cyclic loading with 2000 cycles did not show a significant difference (P = .886) between the 3 groups. The HCS group showed the highest stiffness compared with the HCS-antiGP and LP groups (602 N/mm vs. 540 N/mm vs. 462 N/mm, P = .417), without reaching a statistically significant difference. Ultimate load to failure was also not significantly different on comparison of all 3 groups (P = .297). CONCLUSIONS: Simple coronal shear fractures of the capitellum are biomechanically equally stabilized by HCSs compared with HCSs with an additional antiGP or a posterolateral distal humeral LP. In view of the advantages of less (invasive) metalware, the clinical use of 2 isolated anteroposterior HCSs appears reasonable.
Authors: Paul Borbas; Rafael Loucas; Marios Loucas; Maximilian Vetter; Simon Hofstede; Lukas Ernstbrunner; Karl Wieser Journal: Arch Orthop Trauma Surg Date: 2021-08-23 Impact factor: 2.928