Reverse wedge effect following intramedullary nailing of a basicervical trochanteric fracture variant combined with a mechanically compromised greater trochanter

Abstract

Background: To introduce an unreported intraoperative complication in intramedullary nailing (IN) of an anatomically reduced trochanteric fracture variant characterized by a basicervical fracture line and coronally disrupted greater trochanter (GT). Methods: A total of 414 trochanteric fractures (TF) treated with intramedullary nails from 2013 to 2017 were included in this study. After analysis of intraoperative fluoroscopy data, 33 cases, including 21 females and 12 males, with a mean age of 72.5 years (33 to 96 years) were identified for internal rotation of the cephalocervical fragment and inferior opening at the basicervical fracture line caused by nailing a satisfactorily reduced TF. The morphological features of this group of patients were analyzed on computed tomography (CT) scan. On radiograph, the magnitude of the displacement and final femoral neck-shaft angle (NSA) were measured. Results: CT analysis demonstrated that the basicervical fracture line and the posterolateral fragment (PLF) detached from the GT were the two dominant features of this cohort. They were classified according to the number of main fragments: a 3-fragmentary subgroup containing three consistent fragments (cephalocervical fragment, PLF and distal femoral shaft) and a 4-fragmentary subgroup embracing one additional fragment (lesser trochanter). The four subtypes were as follows: the 3-fragmentary S indicating a small PLF (6 cases), the 3-fragmentary M presenting a moderate PLF (3 cases), the 3-fragmentary L standing for the PLF involving whole lesser trochanter (LT) (4 cases) and the 4-fragmentary GL incorporating separated PLF and LT fragments (20 cases). Geological analysis demonstrated that the majority of the basicervical fracture lines (81.8%) just crossed the center of the piriformis fossa, while the others marginally involved the medial wall of the GT. Postoperatively, the mean width of the inferior opening at the basicervical region was 9.2 ± 4.6 mm. The mean NSA was 135.2 ± 7.8 degrees. The comparison between the 3-and 4-fragmentary subgroups revealed no significant differences in magnitude of displacement and NSA. (Continued on next page)Conclusion: This unreported intraoperative complication predominantly occurred in the intramedullary nailed basicervical trochanteric fracture variant combined with a PLF from the GT. The magnitude of the secondary displacement was substantial and resulted in a relative valgus reduction. This secondary displacement was caused by an impingement of the reamer with the superolateral cortex of the cephalocervical fragment and should be addressed during the operation. Level of evidence: Therapy IV.

Calcar fracture gapping: a reliable predictor of anteromedial cortical support failure after cephalomedullary nailing for pertrochanteric femur fractures

“…During the surgery, anteromedial calcar fracture gapping was frequent. Zhang et al [ 31 , 32 ] reported that an inferior medial gap (mean and standard deviation, 9.2 ± 4.6 mm) appears during intramedullary nailing in basicervical trochanteric fractures, called the reverse wedge effect. In addition, inferior placement of the guidewire is beneficial for acquiring an ideal Cal-TAD.…”

Reverse wedge effect following intramedullary nail fixation of trochanteric fracture, what does it imply?

“…Contrary to the conception of the wedge effect, Zhang et al proposed the “reverse wedge effect” during intraoperative fracture reduction and fixation in a recent issue of the journal [ 8 ]. The reverse wedge effect is described as “the reaming/intramedullary nail(IN) insertion generated internal rotation of the cephalocervical fragment and an inferiorly oriented gap at the primary fracture line (basicervical region)”.…”

“…2 and 3 ). Unfortunately, this issue has not been explored in this cohort with a reverse wedge effect [ 8 ].

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Actualización del tratamiento de las fracturas intertrocantéricas

“…15 Otro desplazamiento posible, aunque poco frecuente, es que, luego de introducir el clavo, se produzca un desplazamiento en valgo de la fractura "efecto cuña reverso". 16 Este tipo de desplazamiento secundario está descrito principalmente en las fracturas con trazo basicervical. Ante esta situación, las posibilidades son: introducir un gancho de hueso o "clamp colineal" y, de esta forma, generar una tracción lateral desde la cortical medial del cuello femoral.…”

“…Ante esta situación, las posibilidades son: introducir un gancho de hueso o "clamp colineal" y, de esta forma, generar una tracción lateral desde la cortical medial del cuello femoral. 16 figura 5. a. Imagen radioscópica de perfil en la que se evidencia la caída posterior del fragmento proximal y el solapamiento de las corticales, lo que imposibilita la reducción cerrada. b y c. Introducción de una clavija de 3 mm en el foco y reducción del desplazamiento.…”