Peroneus brevis as source of instability in Jones fracture fixation

Madeleine Willegger,Reinhard Windhager,Shahin Zandieh,Emir Benca,Reinhard Schuh,Lena Hirtler,Lukas Moser

doi:10.1007/s00264-020-04581-2

Madeleine Willegger, Reinhard Windhager + Show 5 more

Open Access

https://doi.org/10.1007/s00264-020-04581-2

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Abstract

PurposeIntramedullary screw fixation is currently considered the gold standard treatment for Jones fractures in the athlete. Besides biological factors (i.e., poor vascularization), mechanical instability induced by the pull of the peroneus brevis tendon (PBT) contributes to deficient Jones fracture healing. This biomechanical study aimed to simulate loads induced by the PBT at the fifth metatarsal and to compare the stability of two intramedullary screw constructs in a Jones fracture fixation model.MethodsJones fractures were created in 24 human paired specimens, and fixation was achieved with either a solid Jones fracture specific screw (JFXS) (Jones Screw; Arthrex Inc., Naples FL, USA) or a cannulated headless compression screw (HCS) (HCS; DePuySynthes, Solothurn, Switzerland). The PBT was fixed to a mechanical load frame by the use of a cryoclamp. Constructs were loaded in tension for 1000 cycles, followed by an ultimate load test. Construct failure was defined by exceeding 10° of dorsal angulation.ResultsPreliminary failure occurred more often in HCS constructs (33%) compared to JFXS constructs (0%) (P = 0.044). Mean tensile load to failure reached 123.8 ± 91.4 N in the JFXS group and 91.5 ± 62.2 N in the HCS group (P = 0.337). The mean slope of the load-displacement curve was 24.2 ± 10.4 N/mm for JFXS constructs and 24.7 ± 5.5 N/mm for HCS constructs, respectively (P = 0.887).ConclusionThis is the first study evaluating the effect of PBT pull on the mechanical stability of Jones fracture fixation. Higher preliminary failure rates of HCS were found under cyclic loading conditions compared to JFXS.

Highlights

Level of evidence: Level II, controlled laboratory studyElectronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.Jones fractures and proximal fifth metatarsal stress fractures in zones II and III have a notoriously high rate of non-union and delayed union when treated conservatively [1,2,3]
Impaired healing response can be attributed to a compromised blood supply at the metadiaphyseal region [9, 10], but mechanical instability may play a detrimental role in Jones fracture healing [11,12,13]
In another specimen, loosening at the steel cup-machine vice-interface occurred during load to failure testing and it had to be excluded from analysis (JFXS construct)

Summary

Introduction

In order to stabilize the fracture, the use of intramedullary screws dramatically improved union rates and enabled short recovery times with a fast return to sports [6,7,8]. An early mobilization and return to competition is desired, but without compromising the stability of fracture fixation. It was postulated that early return to unrestricted sports activities might contribute to International Orthopaedics (SICOT) (2020) 44:1409–1416 refracture development, screw failure, or non-union. Several reports of athletes sustaining a refracture on the first day of restarting sports activities caught the attention of treating surgeons, and raised the discussion about the ideal screw for stable fracture fixation [14, 15]. Clinical, randomized, controlled studies to assess the different efficacy of screws available are lacking

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