Comparative Safety of the TFN-ADVANCED Proximal Femoral Nailing System: Findings from a U.S. Health-Care Database.

BACKGROUND: Proximal femoral fractures are often treated with cephalomedullary nails. Although nail breakages following fracture repair are infrequent, a recent implant retrieval study suggested that the TFN-ADVANCED (TFNA) Proximal Femoral Nailing System (DePuy Synthes) was susceptible to post-implant breakage. It is unclear whether the risk of breakage among patients who receive the TFNA implant is higher than patients who receive other comparable cephalomedullary nails. The current study was designed to evaluate the comparative risk of breakage of the TFNA nail. METHODS: Using data from a large U.S. health-care database, the current study was designed to determine whether TFNA nails have equal, lower, or higher risk of breakage relative to all other comparable, single-head-element (with no additional lag screws), cephalomedullary nails, the Stryker Gamma3 and the Zimmer Natural Nail, referred to in this study as the non-TFNA group. Data were from patients who received the TFNA implant or non-TFNA nails in 365 hospitals between February 1, 2014, and September 30, 2019. Analysis of nail breakage post-implantation was prespecified as the difference between the TFNA group and the non-TFNA group in cumulative incidence at 18 months, with a prespecified equivalence margin of 0.5%, using data balanced on measured covariates by propensity score weighting. RESULTS: Within the first 18 months of implantation, in 14,370 patients with TFNA nails, there were 27 nail breakages, and in 8,260 patients with non-TFNA nails, there were 29 nail breakages. The mean time to nail breakage was 4.72 months for the TFNA group and 4.05 months for the non-TFNA group. In the balanced data, the risk of breakage at 18 months was 0.26% (95% confidence interval [CI], 0.17% to 0.36%) for the TFNA group and 0.25% (95% CI, 0.05% to 0.45%) for the non-TFNA group, with a risk difference of 0.01% (95% CI, -0.21% to 0.24%). This result indicates that the cumulative incidence of nail breakage was equivalent (between -0.5% and 0.5%) for both nail groups. The risk differences were also within the equivalence margin in subgroup analyses: pertrochanteric fractures only (-0.08% [95% CI, -0.34% to 0.19%]), pertrochanteric or subtrochanteric fractures (-0.04% [95% CI, -0.29% to 0.21%]), and those with International Classification of Diseases, Tenth Revision (ICD-10) data only (0.03% [95% CI, -0.18% to 0.25%]). CONCLUSIONS: The risk of nail breakage was equivalent for TFNA and comparator cephalomedullary nails. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Split Second Effect: The Mechanism of How Equinus Can Damage the Human Foot and Ankle.

We are currently in the process of discovering that many, if not the majority, of the non-traumatic acquired adult foot and ankle problems are caused by a singular etiology: non-neuromuscular equinus or the isolated gastrocnemius contracture. There is no question that this biomechanical association exists and in time much more will be uncovered. There are three basic questions that must be answered: why would our calves tighten as we normally age, how does a tight calf, or equinus, actually cause problems remotely in the foot and ankle, and how do the forces produced by equinus cause so many seemingly unrelated pathologies in the foot and ankle? The purpose of this paper is to address the second question: how does a tight calf mechanically cause problems remotely in the foot and ankle? There has been little evidence in the literature addressing the biomechanical mechanisms by which equinus creates damaging forces upon the foot and ankle, and as a result, a precise, convincing mechanism is still lacking. Thus, the mere concept that equinus has anything to do with foot pathology is generally unknown or disregarded. The split second effect, described here, defines exactly how the silent equinus contracture creates incremental and significant damage and injury to the human foot and ankle resulting in a wide variety of pathological conditions. The split second effect is a dissenting theory based on 30 years of clinical and academic orthopedic foot and ankle experience, keen clinical observation along the way, and review of the developing literature, culminating in examination of many hours of slow motion video of normal and abnormal human gait. To my knowledge, no one has ever described the mechanism in detail this precise.

The gastrocnemius: a new paradigm for the human foot and ankle.

A silent gastrocnemius contracture can gradually do so much harm when left undetected and unattended. The calf is a common source of a majority of acquired, nontraumatic adult foot and ankle problems. When it comes to surgical lengthening procedures, whether at the Achilles, at the musculotendinous junction, or more proximal, the search must move on to find the safest, most accurate, and quickest recovery method possible. Addressing the calf contracture as definitive treatment and, better yet, as prevention will no doubt become a mainstay of the treatment of many foot and ankle problems.