Failure Mode of Transcondylar Screws Used for Treatment of Incomplete Ossification of the Humeral Condyle in 5 Dogs

Abstract

Objective-To investigate the mode of failure of transcondylar screws retrieved from dogs previously treated for incomplete ossification of the humeral condyle (IOHC). Study Design-Metallurgical study. Sample Population-Broken screws (n ¼ 5) from dogs with IOHC. Methods-Broken transcondylar bone screws were retrieved from dogs that had apparently successful surgery for IOHC. Screws were measured and examined using scanning electron microscopy (SEM) and energy-dispersive analysis by X-rays (EDX). Results-EDX confirmed that screws were made from 316L stainless steel and there was no evidence of significant corrosion or manufacturing faults that might have contributed to implant failure. SEM of the fractured surface of screws revealed a similar and complex pattern of fatigue failure characterized by multidirectional fatigue cracks and the presence of several initiation sites. All screws had signs of fatigue failure because of multidirectional forces of variable magnitude. Conclusions-Intercondylar instability is a feature of IOHC that persists despite placement of a transcondylar screw. Clinical Relevance-The pathogenesis of IOHC involves chronic intercondylar instability and its treatment using even relatively large transcondylar screws has a risk of late implant failure. r

Postoperative Complications after Surgical Management of Incomplete Ossification of the Humeral Condyle in Dogs

“…Follow‐up varied from 6 to 192 weeks. The variable length of postoperative follow‐up available for analysis may have affected the incidence of this complication as implant failure may occur at a significant length of time postoperatively and some dogs were lost to follow‐up after 6 weeks 12 …”

“…Implant failure has been reported as a complication of transcondylar screw placement. 4,5,12 Failure of the intracondylar fissure to fuse leads to continued loading of the screw at its midpoint where it bridges the fissure and leads to fatigue failure. 12 The incidence of transcondylar screw failure our dogs was lower than we suspected anecdotally.…”

“…Autogenous bone grafting can be used in conjunction with a metallic implant 10 . The reported postoperative complications for transcondylar screw placement and fracture repair include implant failure, seroma formation, and development of SSI 4,5,11,12 . The prevalence of SSIs in veterinary medicine is reported at between 2.5% and 5.8% 13–16 …”

“…10 The reported postoperative complications for transcondylar screw placement and fracture repair include implant failure, seroma formation, and development of SSI. 4,5,11,12 The prevalence of SSIs in veterinary medicine is reported at between 2.5% and 5.8%. [13][14][15][16] Anecdotally, prophylactic screw placement for the management of IOHC is associated with high levels of postoperative complications.…”

Evaluation of LED therapy at 945nm on bone repair by micro x-ray fluorescence spectroscopy and scanning electron microscopy

“…Na, Mg, Cl, P, and Ca) [41,42,43,44] . In the physical process relevant to the analysis of this phenomenon, radiation interacts with matter, including the photoelectric effect.…”