Reliability analysis of CT torsion assessment after closed cephalomedullary nailing of trochanteric femoral fractures. A comparison study of six established methods.

BACKGROUND: Posttraumatic maltorsion and implant failure after closed reduction of proximal femoral fractures remain a cause of concern. Although the reproducibility of torsion measuring techniques on CT for femoral shaft fractures has been thoroughly analyzed, little is known about the trochanteric fractures. Apart from the well-known CT limitations, posttraumatic alteration of bony landmarks makes torsional assessment even more challenging. Main goal of this study was to examine the reliability of different CT techniques on trochanteric femoral fractures after closed nail fixation. Secondary goal was to see whether the measurements within the examined population were influenced by the fracture type and patient age or BMI. METHODS: 20 cases (AO.31-A1 or -A2) were retrospectively examined. Six established CT techniques for torsional assessment were performed from three different investigators twice at different time points. The intraclass correlation coefficient (ICC for 95% CI) was used to analyze the interobserver and intraobserver reliability. RESULTS: The Hernandez method (0.986) followed by the Jend method (0.982) by a mean difference of <1° showed the highest reliability. Although increasing fracture complexity from A1 to A2 led to an overall worsening of the measurement precision, the Hernandez and Jend techniques revealed a very good consistency. Within the examined population, age and BMI had no impact on the precision of the measurements. CONCLUSIONS: The Hernandez and Jend methods represent reliable alternatives for torsional assessment of trochanteric femur fractures treated with closed nail fixation when compared to the other measurement techniques here involved. Documentation of the torsion measuring method used in each case constitutes an essential element of the radiological reports.

Partial descemetorhexis for delayed Descemet membrane detachment following penetrating keratoplasty, suggestion of a pathomechanism.

PURPOSE: to report a case of delayed Descemet membrane detachment (DMD) 45 years after penetrating keratoplasty (PK) for keratoconus and its management with a partial descemetorhexis after failed air/gas descemetopexy. A pathomechanism of DMD is proposed based on the anatomic appearance of the DMD and the success of descemetorhexis. OBSERVATIONS: a 60-year old male presented with acute corneal edema of his left eye 45 years after successful PK for keratoconus. Anterior segment ocular coherence tomography (AS-OCT) revealed a wide area of DMD without a visible tear. Reattachment was tried using air and gas descemetopexy with only temporary success. A partial descemetorhexis was then performed just centrally to the graft-host interface and only in the detached area followed by injection of gas bubble. Complete reattachment of Descemet membrane (DM) on the 1st post-operative day was achieved. This anatomical success was maintained 3 months post-surgery and accompanied by decrease of central corneal thickness, however with uncomplete restoration of visual acuity. CONCLUSION: delayed DMD following KP for keratoconus should be differentiated from acute graft rejection. It could be a result of Descemet tear, but in some cases and despite careful observation of AS-OCT no tear could be seen. In such cases, a tractional detachment of DM might be the underlying pathomechanism and descemetorhexis could help manage it. This new surgical approach might help avoid a re-keratoplasty. IMPORTANCE: This is the first case report describing success of partial descemetorhexis as a surgical management option for delayed DMD and suggesting a pathogenesis based on this success. This might help avoid re-keratoplasty as a management of this rare complication.