Feline Diaphyseal Fractures: Management and treatment options

Impact and torsional behavior of additive layer-manufactured biopolymer: An advancement for orthopedic applications

Distal ulna locking bone plates (DLBPs) are commonly employed in the treatment of distal ulna fractures. However, commercially available metallic bone plates experience stress shielding and lack corrosion resistance. Poly lactic acid (PLA) is highly favored biopolymer due to its biocompatible and bioabsorbable nature with human tissues. The use of additive layer manufacturing (ALM) is gaining attention for creating customized implants with intricate structures tailored to patient autonomy. ALM-based PLA bone plates must provide high resistance against impact and torsional forces, necessitating the adjustment of printing process parameters. This study focuses on examining the influence of key printing parameters, on the impact strength and torque-withstanding capability of DLBPs. Experimental results, along with microscopic images, reveal that an increase in infill density (IF) and wall thickness imparts strong resistance to layers against crack propagation under impact and torsional loads. On the contrary, an increase in layer height and printing speed leads to delamination and early fracture of layers during impact and torsional testing. IF significantly contributes to improving the impact strength and torque-withstanding capability of DLBPs by 70.53% and 80.65%, respectively. The study highlights the potential of the ALM technique in developing DLBPs with sufficient mechanical strength for biomedical applications.

Minimally Invasive Plate Osteosynthesis (MIPO) of Comminuted Radial Fractures Using a Locking Plate Contoured on a 3D-Printed Model of the Feline Antebrachium: A Cadaveric Study

(1) Background: Due to the unique structural and functional characteristics of the forelimb in cats, fractures of the radius and ulna are best repaired using internal fixation and stabilization in accordance with AO principles. This study presents the results of reduction of 42 cadaveric comminuted feline radial fractures reduced by minimally invasive plate osteosynthesis (MIPO). (2) Methods: Radius fractures were created on 21 pairs of forelimbs with intact bones. MIPO was then performed using two locking bone plates pre-contoured on 3D-printed bone models of the antebrachium of a male and a female cat. Pre- and postoperative radiographs were taken, and radius length and anatomical lateral distal radial angle (aLDRA) were measured. (3) Results: All fractures were classified as complex diaphyseal fractures of the radius. The radial bone length did not change significantly after surgery (F1,18 = 0.01, p = 0.933). However, the aLDRA was modified after surgery (F1,18 = 7.51, p = 0.013), but this change was only observed in females, in whom the aLDRA was significantly reduced (p = 0.035) compared to the value determined by the shape of the plate. In males, the pre- and postoperative aLDRA values were similar (p = 0.824). In 40 cases, alignment, adjacency of bone fragments, and apparatus were judged to be satisfactory. In two cases, the plate was fixed to the proximal radius and distal ulna due to misidentification of the distal radius. In both cases, revision surgery and correct fixation of the radius gave proper alignment, adjacency, and apparatus. (4) Conclusion: A pre-contoured plate on a 3D-printed model of the male and female domestic cat antebrachium was suitable for the reduction and stabilization of comminuted radial fractures in a cohort of domestic cat cadavers without the need to print individual antebrachial bone models for each patient.

Feline radial and ulnar diaphyseal fractures: a retrospective study of 49 cases comparing single bone fixation and dual bone fixation

OBJECTIVES

The objectives of this study were to report the complications in radial and ulnar diaphyseal fractures in cats and to compare the differences in outcome between single and dual bone internal fixation.

METHODS

Medical records between 2004 and 2022 were searched retrospectively for cats with antebrachial diaphyseal fractures treated with internal bone-plate fixation. In total, 49 cases were included from six referral hospitals, including one teaching hospital. Patient information was collated, including fracture configuration, location, repair method and clinical outcome as assessed by veterinary physical examination, radiography and owner questionnaire.

RESULTS

A total of 47 cats (mean age 4.2 years) were included. Fractures were located distally (24/49, 49%), proximally (13/49, 26.5%) and mid-diaphyseally (12/49, 24.5%). Dual bone fixation was used in 13/49 (26.5%) cases, with only 1/13 (7.7%) having major complications. By comparison, 4/36 (11.1%) of single plated fractures had major complications. Single bone fixation was 14.25 times more likely (95% confidence interval [CI] 2.07-97.99) to have a successful outcome (veterinarian-assigned score of 0) compared with dual bone fixation (P = 0.007). When evaluating owner-assessed outcomes, single bone fixation was 9.4 times more likely (95% CI 1.4-61.96) to have a successful outcome (owner score of 0) compared with dual bone fixation (P = 0.019).

CONCLUSIONS AND RELEVANCE

Fractures that were repaired with single bone fixation had a greater chance of a better outcome. Although the difference was not significant, there was a higher major complication rate and a lower minor complication rate for cases treated with single bone fixation compared with dual bone fixation. The majority of fractures were located in the distal diaphysis. Comminution of the fracture and concurrent orthopaedic issues did not significantly affect the outcome. Further prospective studies with standardised follow-up, radiographic assessment, surgeon and implants are required to truly assess the difference between dual and single bone fixation.

Long-term outcomes of atrophic/oligotrophic non-unions in dogs and cats treated with autologous iliac corticocancellous bone graft and circular external skeletal fixation: 19 cases (2014-2021)

OBJECTIVES

To determine the short- and long-term outcomes and complications in dogs and cats undergoing surgical treatment for viable oligotrophic and nonviable atrophic non-unions using circular external skeletal fixation and autologous corticocancellous bone graft.

MATERIALS AND METHODS

In this case series, the medical records and radiographs of all dogs and cats with radius/ulna and tibia/fibula viable oligotrophic and nonviable atrophic non-unions treated with corticocancellous bone graft and circular external skeletal fixation at two referral veterinary hospitals between 2014 and 2021 were retrospectively reviewed. The long-term follow-up was 1 year or greater.

RESULTS

Thirteen dogs and six cats with 19 non-union fractures met the inclusion criteria for the study. Eighteen non-union fractures (94.7%) healed and one did not. Five patients (26%) had minor perioperative period complications (<3 months). The patient that did not achieve bone union underwent revision surgery with internal fixation (plate and screws) and autologous cancellous bone graft. Fifteen (78.9%) cases returned to full function and three (15.8%) cases returned to acceptable function in the long-term follow-up period.

CLINICAL SIGNIFICANCE

The use of circular external skeletal fixation associated with autologous corticocancellous bone graft for the treatment of radius/ulna and tibia/fibula atrophic/oligotrophic non-union fractures in dogs and cats was considered successful in the majority of patients and was free of major or catastrophic complications.