Radiographic Outcomes of Isolated Subtalar Joint Arthrodesis With Varying Fixation Technique

Subtalar joint (STJ) arthrodesis is a well-established and accepted surgical procedure utilized for the treatment of various hindfoot conditions including primary or posttraumatic subtalar osteoarthritis, hindfoot valgus deformity, hindfoot varus deformity, complex acute calcaneal fracture, symptomatic residual congenital deformity, tarsal coalition, and other conditions causing pain and deformity about the hindfoot. Union rates associated with isolated subtalar joint arthrodesis are generally thought to be favorable, though reports have varied significantly, with non-union rates ranging from 0 to 46%. Various fixation constructs have been recommended for STJ arthrodesis. The purpose of this study was to compare radiographic union in a 2-screw fixation technique to a 3-screw fixation technique for patients undergoing primary isolated STJ arthrodesis. To this end, we retrospectively reviewed 54 patients; 26 in the 2-screw group and 28 in the 3-screw group. We found the median time to radiographic union to be 9 weeks for the 2-screw cohort and 7 weeks for the 3-screw cohort. Additionally, we found that the 2-screw fixation cohort had a radiographic non-union rate of 26.9% while the 3-screw cohort had no non-unions. We conclude that the use of a 3-screw construct for isolated STJ arthrodesis has a lower non-union rate and time to union when compared to the traditional 2-screw construct and should be considered as a fixation option for STJ arthrodesis.

Forefoot Adduction, Hindfoot Varus or Pes Cavus: Risk Factors for Fifth Metatarsal Fractures and Jones Fractures? A Systematic Review and Meta-Analysis

The origin of fractures of the fifth metatarsus and Jones fracture is not clear. The goal of this study was to investigate the evidence of anatomical deformities such as metatarsus adductus, hindfoot varus, or pes cavus as risk factors for this pathology. A literature search of records related to the review question was performed screening PubMed/Medline, Embase and Cochrane library databases (last update: May 2020) according to PRISMA guidelines. A meta-analysis was performed using the mean difference of the assessed angles (in patients with the fractures vs controls) as outcome measure to summarize literature findings about metatarsus adductus angle (MAA) indicating forefoot adduction, calcaneal pitch angle (CP) indicating hindfoot cavus and varus deformity and Talo-1^st metatarsus angle/Meary's angle (T1^stMA) for varus alignment. Eight studies were included in the qualitative analysis (296 patients), 5 in the quantitative synthesis (132 patients). The pooled mean difference of MAA between fracture versus control group on a per patient-based analysis was 4.62 (95% CI 1.31-7.92). Statistical heterogeneity among studies was detected (I-Square: 76.1%), likely due to different patient groups and low number of studies. The pooled mean differences of CP and T1^stMA among fracture group versus controls did not show statistical significance. Despite limited literature data, metatarsus adductus deformity seems to be correlated with higher risk of proximal metatarsal fractures and Jones fracture. A significant relationship between hindfoot varus or pes cavus and these fractures was not demonstrated. Further studies and trials are warranted to shed more lights on this topic.

Intramedullary Screw Fixation of a Proximal Fifth Metatarsal Stress Fracture in an Elite Athlete: A Case Report

Intramedullary screw fixation of proximal fifth metatarsal fractures is a simple surgical procedure, enabling early postoperative weight-bearing and subsequently rapid return to competitive sport, which is of great significance for elite athletes. The procedure is described in an elite basketball player in this article. Pes cavus and hindfoot varus alignment potentiate cyclic loading onto the fifth metatarsal and should be addressed as it may represent underestimated factors concerning fracture prognosis.

Effects of Medial Displacement Calcaneal Osteotomy and Calcaneal Z Osteotomy on Subtalar Joint Pressures: A Cadaveric Flatfoot Model

Medial displacement calcaneal osteotomies have been shown to be successful in the surgical management of adult acquired flatfoot, in particular, stage 2 deformity. Classically, the medial displacement calcaneal osteotomy technique has been performed. However, a calcaneal Z osteotomy has been more recently described and applied in the surgical management of flatfoot deformity. Although the potential advantages of the calcaneal Z technique have been reported, data on its effect on the subtalar joint are lacking. A validated flatfoot model was induced in 8 cadaveric feet that had been randomly assigned to either medial displacement calcaneal osteotomy (n = 4) or calcaneal Z osteotomy (n = 4). The feet were loaded through the tibia with a constant ground reaction force of 400 N, with a simultaneous increase in the Achilles tendon force to 300 or 500 N. The subtalar joint pressures were recorded before and after osteotomy. We did not detect any statistically significant differences between the 2 techniques in terms of their effects on subtalar joint pressure.

Ankle joint pressure changes in a pes cavovarus model: supramalleolar valgus osteotomy versus lateralizing calcaneal osteotomy

BACKGROUND

A fixed cavovarus foot deformity can be associated with anteromedial ankle arthrosis due to elevated medial joint contact stresses. Supramalleolar valgus osteotomies (SMOT) and lateralizing calcaneal osteotomies (LCOT) are commonly used to treat symptoms by redistributing joint contact forces. In a cavovarus model, the effects of SMOT and LCOT on the lateralization of the center of force (COF) and reduction of the peak pressure in the ankle joint were compared.

METHODS

A previously published cavovarus model with fixed hindfoot varus was simulated in 10 cadaver specimens. Closing wedge supramalleolar valgus osteotomies 3 cm above the ankle joint level (6 and 11 degrees) and lateral sliding calcaneal osteotomies (5 and 10 mm displacement) were analyzed at 300 N axial static load (half body weight). The COF migration and peak pressure decrease in the ankle were recorded using high-resolution TekScan pressure sensors.

RESULTS

A significant lateral COF shift was observed for each osteotomy: 2.1 mm for the 6 degrees (P = .014) and 2.3 mm for the 11 degrees SMOT (P = .010). The 5 mm LCOT led to a lateral shift of 2.0 mm (P = .042) and the 10 mm LCOT to a shift of 3.0 mm (P = .006). Comparing the different osteotomies among themselves no significant differences were recorded. No significant anteroposterior COF shift was seen. A significant peak pressure reduction was recorded for each osteotomy: The SMOT led to a reduction of 29% (P = .033) for the 6 degrees and 47% (P = .003) for the 11 degrees osteotomy, and the LCOT to a reduction of 41% (P = .003) for the 5 mm and 49% (P = .002) for the 10 mm osteotomy. Similar to the COF lateralization no significant differences between the osteotomies were seen.

CONCLUSION

LCOT and SMOT significantly reduced anteromedial ankle joint contact stresses in this cavovarus model. The unloading effects of both osteotomies were equivalent. More correction did not lead to significantly more lateralization of the COF or more reduction of peak pressure but a trend was seen.

CLINICAL RELEVANCE

In patients with fixed cavovarus feet, both SMOT and LCOT provided equally good redistribution of elevated ankle joint contact forces. Increasing the amount of displacement did not seem to equally improve the joint pressures. The site of osteotomy could therefore be chosen on the basis of surgeon's preference, simplicity, or local factors in case of more complex reconstructions.