Evaluation of Two Types of Intramedullary Jones Fracture Fixation in a Cyclic and Ultimate Load Model

Fifth Metatarsal Fractures

Fifth metatarsal features are the most common fractures in the foot. They have a long history that has resulted in many classification systems and little consensus on appropriate treatment. Although there is some agreement among experts, there are also many questions yet to be answered. There is a general consensus that dancer's fractures and zone 1 fractures can generally be treated nonoperatively. There is much more debate about zone 2 and 3 fractures and appropriate treatment guidelines. The authors review the current literature and give the recommendation for treatment based on their experience in a community-based private practice.

Biomechanical comparisons of F.E.R.I. techniques with different type of intramedullary screws fixation for Jones fractures

Introduction: Jones fractures frequently fail to unite, and adequate fixation stability is crucial. This study aimed to elucidate the biomechanical stability of various intramedullary screw fixation constructs. Methods: Jones fracture model over the proximal 5th metatarsal of artificial bone was created in all specimens. Six groups were divided based on varied screw constructs with different screw lengths, either 30 or 40 mm, including cannulated screws-C30 and C40 groups, one high-resistance suture combined with intramedullary cannulated screws (F.E.R.I. technique)-CF30 and CF40 groups, and second-generation headless compression screws (SG-HCS) -HL30 and HL40 groups. Mechanical testing was conducted sequentially, and the maximal force (N) and stiffness (N/mm) of all constructs were recorded. Results: The maximal force (N) at 1.0 mm downward displacement in C30, C40, CF30, CF40, HL30, and HL40 groups were 0.56 ± 0.02, 0.49 ± 0.02, 0.65 ± 0.02, 0.49 ± 0.01, 0.68 ± 0.02, and 0.73 ± 0.02, respectively, and the stiffness (N/mm) in subgroups were 0.49 ± 0.01, 0.43 ± 0.01, 0.67 ± 0.01, 0.42 ± 0.01, 0.61 ± 0.01, and 0.58 ± 0.02, respectively. SG-HCS subgroups exhibited greater maximal force and stiffness than conventional cannulated screws. Screws of 30 mm in length demonstrated better stability than all 40 mm-length screws in each subgroup. In C30 fixation, the stiffness and maximum force endured increased by 1.16 and 1.12 times, respectively, compared with the C40 fixation method. There were no significant differences between CF30 and SG-HCS groups. Only the F.E.R.I technique combined with the 4.5 mm cannulated screw of 30 mm in length increased the biomechanical stability for Jones fractures. Discussion: These biomechanical findings help clinicians decide on better screw fixation options for greater stability in Jones fractures, especially when large-diameter screws are limited in use. However, this biomechanical testing of intramedullary screw fixation on Jones fracture model lacks clinical validation and no comparisons to extramedullary plate fixations. Moving forward, additional clinical and biomechanical research is necessary to validate our findings.

Biomechanical evaluation of the proximal chevron osteotomy in comparison to the Lapidus arthrodesis for the correction of hallux valgus deformities

Purpose

The proximal chevron osteotomy and the modified Lapidus arthrodesis are both procedures utilized for deformity correction in patients with severe symptomatic hallux valgus. The aim of the current study was to compare their biomechanical stability when using locking plate fixation.

Methods

Twelve matched pairs of human anatomical lower leg specimens underwent on one side a proximal chevron osteotomy with a medial locking plate and on the other side a modified Lapidus arthrodesis with a plantar locking plate utilizing an interfragmentary compression screw. All specimens underwent bone mineral density (BMD) assessment and were tested in a servohydraulic load frame which applied a load on the centre of the metatarsal head over 1000 loading cycles with subsequently ultimate load testing. Displacement of the proximal and distal bone segment, ultimate load, and bending stiffness were analyzed.

Results

Mean displacement of both procedures showed no statistically significant difference throughout all the loading cycles (0.213 ≤ p ≤ 0.834). The mean ultimate load of the proximal chevron osteotomy was 227.9 N (± 232.4) and of the modified Lapidus arthrodesis 162.9 N (± 74.6) (p = 0.754). The proximal chevron osteotomy (38.2 N/mm (± 24.9)) had a significantly higher bending stiffness compared to the modified Lapidus arthrodesis (17.3 N/mm (± 9.9)) (p = 0.009). There was no correlation between BMD and displacement in all loading cycles, ultimate load, and bending stiffness of either procedure (p > 0.05).

Conclusion

Although the bending stiffness of the chevron osteotomy was higher, there was no statistically significant difference between the surgical techniques in mean displacement and ultimate load. The BMD did not influence the overall stability of either reconstruction. Locking plate fixation increases the clinical value of the modified Lapidus arthrodesis by outweighing most of the biomechanical disadvantages in comparison to the proximal chevron osteotomy.

The Effectiveness of Intramedullary Screw Fixation Using the Herbert Screw for Fifth Metatarsal Stress Fractures in High-Level Athletes

BACKGROUND

Intramedullary screw fixation is the most common operative procedure used for treatment of fifth metatarsal stress fractures in athletes. However, the optimal implant in intramedullary screw fixation is still being investigated.

PURPOSE

To review experiences with intramedullary screw fixation using the Herbert screw for fifth metatarsal stress fractures in high-level athletes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors retrospectively analyzed 37 high-level athletes (Tegner activity score ≥7) who underwent intramedullary screw fixation using the Herbert screw for fifth metatarsal stress fractures between August 2005 and August 2017. The minimum follow-up period of the patients was 2 years. In assessing the surgical results, time to obtain bone union, time to return to original level of sport participation, and treatment failures/complications were reviewed. Additionally, the effect of intraoperative plantar gap widening caused by the screw insertion was analyzed. The surgical results of the 2 groups, the no-gap group (intraoperative plantar gap widening, <1 mm) and the gap group (intraoperative plantar gap widening, ≥1 mm), were compared, while correlations between intraoperative plantar gap widening and the surgical results were statistically analyzed.

RESULTS

Bone union and return to the original sport were attained in all patients without treatment failures/complications such as delayed union, nonunion, or refracture. The mean time to obtain bone union was 10.1 weeks, and the mean time to return to sport was 10.9 weeks. In comparing the no-gap group (n = 16) and the gap group (n = 21), no significant differences in the time to obtain bone union (P = .392) or to return to sport (P = .399) were noted. Additionally, there was no correlation between intraoperative plantar gap widening and the time to obtain bone union (r = 0.131; P = .428) or to return to sport (r = 0.160; P = .331).

CONCLUSION

The use of the Herbert screw for intramedullary screw fixation to treat fifth metatarsal stress fractures in high-level athletes provided satisfactory results enabling all the athletes to return to the original sport without treatment failures/complications. Additionally, intraoperative plantar gap widening does not affect the surgical results using this technique.

Jones type fifth metatarsal fracture fixation in athletes: A review and current concept

Jones type fifth metatarsal fracture is a common occurrence among athletes at all levels. These fractures may occur due to several mechanisms, but inversions and twisting injuries are considered some of the leading causes in sports. However, while Jones fracture incidences are frequent in the sporting world, there is still a lack of consensus on how such fractures should be effectively managed. There are numerous treatment options for patients with fifth metatarsal Jones fractures. The role of nonoperative treatment remains controversial, with concerns about delayed union and nonunion. Surgical stabilization of metatarsal Jones fractures is therefore often recommended for athletes, as it is often associated with a low number of complications and a higher rate of union than nonoperative management. This review will focus on literature regarding the prevalence of Jones type fifth metatarsal fracture, alongside the efficacy of both conservative and surgical treatment within this population.

Jones Fracture Management in Athletes

Jones fractures in both elite and recreational athletes are best treated with surgical fixation, given superior results as compared to nonoperative management. While screw specifics remain controversial, intramedullary screw fixation is established as the standard surgical technique. Plate fixation also has shown excellent outcomes. Complications of refracture, nonunion, and delayed union require careful evaluation for contributions of early return to play, implant characteristics, and anatomic/metabolic abnormality. Revision fixation with autograft and biologic augmentation is supported in the literature, with ongoing inquiry to optimizing specific implants and adjuvants.

Peroneus brevis as source of instability in Jones fracture fixation

Purpose

Intramedullary 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.

Methods

Jones 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.

Results

Preliminary 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).

Conclusion

This 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.

Electronic supplementary material

The online version of this article (10.1007/s00264-020-04581-2) contains supplementary material, which is available to authorized users.