External Fixators and Minimally Invasive Osteosynthesis in Small Animal Veterinary Medicine

The Impact of Ultrashort Pulse Laser Structuring of Metals on In-Vitro Cell Adhesion of Keratinocytes

Besides the need for biomaterial surface modification to improve cellular attachment, laser-structuring is favorable for designing a new surface topography for external bone fixator pins or implants. The principle of this study was to observe how bioinspired (deer antler) laser-induced nano-microstructures influenced the adhesion and growth of skin cells. The goal was to create pins that allow the skin to attach to the biomaterial surface in a bacteria-proof manner. Therefore, typical fixator metals, steel, and titanium alloy were structured using ultrashort laser pulses, which resulted in periodical nano- and microstructures. Surface characteristics were investigated using a laser scanning microscope and static water contact angle measurements. In vitro studies with human HaCaT keratinocytes focused on cell adhesion, morphology, actin formation, and growth within 7 days. The study showed that surface functionalization influenced cell attachment, spreading, and proliferation. Micro-dimple clusters on polished bulk metals (DC20) will not hinder viability. Still, they will not promote the initial adhesion and spreading of HaCaTs. In contrast, additional nanostructuring with laser-induced periodic surface structures (LIPSS) promotes cell behavior. DC20 + LIPSS induced enhanced cell attachment with well-spread cell morphology. Thus, the bioinspired structures exhibited a benefit in initial cell adhesion. Laser surface functionalization opens up new possibilities for structuring, and is relevant to developing bioactive implants in regenerative medicine.

A Bilateral Acetabular Physeal Fracture Treated with External Fixation in an Immature Cat

This study aimed to assess the outcome of a bilateral acetabular physeal fracture treated with external fixation in an immature cat, a surgical technique not usually employed in immature patients. The fixator took 40 days, and it was removed after radiographic bone healing was achieved. No significant complications related to the technique were identified, and the outcome was classified as good based on the functional assessment and pain scales employed. The use of external fixation for stabilising acetabular fractures in immature cats should be considered a viable technical option, especially for minimally invasive stabilisation.

Surgical Management of a Salter-Harris Type I Distal Physeal Fracture of the Tibia in a Calf: A Case Report

Fractures are common conditions in cattle, including tibial fractures. Physeal tibial fractures are more specific and less frequently met in field conditions. A calf with a Salter-Harris type I distal physeal fracture of the tibia was referred to the National Veterinary School of Toulouse (ENVT), France. Although the use of external fixators in the treatment of tibial fractures is common, distal physeal tibial fractures require a different and specific technique involving them. They were first used as a lever arm to reduce the fracture due to the severe displacement. A hock joint bypass was then performed. Six weeks after treatment, the calf recovered successfully from the use of the affected limb without any adverse sequelae. The present case provides management of a distal tibial fracture using external fixators. This innovative and accessible surgical technique may be used by veterinary practitioners in future similar cases of distal tibial fractures when pins in the distal end cannot be inserted.

Stiffness of a type II external skeletal fixator and locking compression plate in a fracture gap model

OBJECTIVE

To compare the stiffness of constructs fixed with a type II external skeletal fixator (ESF) or a 3.5-mm locking compression plate (LCP) in axial compression and bending with a fracture gap model.

STUDY DESIGN

Quasi-static four-point bending and axial compression tests.

SAMPLE POPULATION

Ten LCP and 10 ESF immobilizing epoxy cylinders with a 40-mm fracture gap.

METHODS

Five constructs of each type were tested in nondestructive mediolateral (ML) four-point bending and then rotated and tested in nondestructive craniocaudal (CC) four-point bending. Five additional constructs of each type were tested in nondestructive axial compression. Stiffness was compared between loading modes by construct type and between construct types by loading mode.

RESULTS

Type II ESF were stiffer than LCP in ML bending (difference, 1474 N/mm, P < .0001) and in axial compression (difference, 458 N/mm, P = .008) but not in CC bending (P = .1673). Type II ESF were stiffer in ML bending than in CC bending (difference, 999 N/m, P < .0001), while LCP were stiffer in CC bending than in ML bending (difference, 634 N/mm, P < .0001).

CONCLUSION

Type II ESF generated stiffer constructs compared with LCP in ML bending and in axial compression without a difference in CC bending. External skeletal fixator and LCP bending stiffness varied by loading direction.

CLINICAL SIGNIFICANCE

A type II ESF should be considered in a comminuted fracture requiring increased stability in ML and axial directions.

SUCCESSFUL REPAIR OF ANTEBRACHIAL FRACTURES WITH EXTERNAL SKELETAL FIXATION IN THREE MACROPODS

Three captive macropods comprising three different species sustained unilateral antebrachial fractures. All fractures were assumed to be trauma related, although the specific circumstances surrounding each case was unknown. Each fracture was surgically repaired with type Ia (unilateral, monoplanar) external skeletal fixators, which were all removed approximately 3 mo postoperatively. Although each animal experienced at least one complication, all animals showed adequate bridging and remodeling at the fracture sites and had good-to-excellent return to normal function after fixator removal. This case series is the first to describe the successful repair of antebrachial fractures using external skeletal fixation in captive macropods and details some of the complications that can occur with postoperative management of captive animals.

Key Ring Fixator: A Novel External Fixation Technique for Avian Long Bone Stabilization

A 12-year-old blue-fronted Amazon parrot (Amazona aestiva) of unknown sex (case 1) and a 14-year-old female hybrid Catalina macaw (Ara ararauna × Ara macao) (case 2) were evaluated and treated for an open tarsometatarsal fracture and a tibiotarsal fracture, respectively. In case 1, 1 month of external coaptation resulted in a delayed union, significant osteolysis, and presumptive osteomyelitis, which led to the decision to treat with a key ring fixator. In case 2, a key ring fixator was chosen for fracture repair because of presumed resistance to destruction by the bird. In both cases, fractures were stabilized with makeshift circular external fixators composed of key rings, K-wires, orthopedic wire, and acrylic resin. After key ring fixator removal, radiographs confirmed complete bone healing. Both patients had acceptable function of the affected limbs 5 years (case 1) and 2 years (case 2) after their procedures. The key ring fixator described in this report is a viable option for fracture repair in pelvic limbs of moderately sized birds (300-1500 g).

Pitfalls of Minimally Invasive Fracture Repair

Minimally invasive fracture repair (MIFR) is the ultimate culmination of current osteosynthesis concepts that emphasize the preservation and enhancement of the biologic components of fracture healing. Although the "less is more" approach to tissue dissection and fracture exposure and handling that defines MIFR has numerous reported advantages over more traditional open surgical treatments, it does present some unique challenges and important considerations for the surgeon. This article describes some of the general MIFR challenges a surgeon may encounter.

Perceptions of minimally invasive osteosynthesis: A 2018 survey of orthopedic surgeons

OBJECTIVE

To report perspectives of minimally invasive osteosynthesis (MIO) techniques in veterinary surgical practice in 2018.

STUDY DESIGN

Electronic questionnaires.

SAMPLE POPULATION

Diplomates and residents of the American College of Veterinary Surgery and European College of Veterinary Surgery and members of the Veterinary Orthopedic Society.

METHODS

Survey questions pertaining to MIO and minimally invasive plate osteosynthesis (MIPO) were sent electronically to the sample population. Questions assessed training, current caseload, benefits, and limitations of MIO and MIPO.

RESULTS

Two hundred fifty-six veterinary surgeons completed questions pertaining to MIO, and 238 veterinary surgeons completed questions pertaining to MIPO. With regard to MIO, only 16% of respondents reported that they performed MIO regularly or exclusively, and 62% wanted to perform more MIO than they were currently undertaking. Tibial fractures were most commonly selected for MIO/MIPO stabilization techniques in both cats and dogs. Challenges in achieving adequate fracture reduction were identified as the greatest limitations of MIO/MIPO techniques. Forty-three percent of respondents felt there were not enough MIPO training opportunities.

CONCLUSION

Currently, MIO/MIPO techniques are performed infrequently, with a large proportion of respondents revealing that they would like to perform more in the future. There is also evidence that additional training opportunities would be welcomed for MIPO.

CLINICAL SIGNIFICANCE

The results of our survey provide evidence that, despite the benefits of MIO and MIPO compared with more traditional fracture stabilization approaches, significant barriers must be overcome before the techniques are likely to be more widely adopted.

Relative stiffness of 3 bandage/splint constructs for stabilization of equine midmetacarpal fractures

OBJECTIVE

Determine the relative stiffness of 3 bandage/splint constructs intended for emergency fracture stabilization.

DESIGN

Experimental model. A single plane free end deflection model was developed to simulate the forces placed on a bandage/splint construct during stabilization of a complete mid-metacarpal bone fracture. The total deflection of the model in one plane was measured following application of 3 different bandage/splint combinations including a classic, 3 layered Robert Jones Bandage (RJB) with a splint placed on the outside of the bandage (RJB-3), an RJB with splint placed after the first of 3 bandage layers (RJB-1), and a single layer full limb bandage with external splint (SS). Comparisons were made between the deflections of the model with each bandage/splint combinations in an effort to determine the most effective method for field fracture stabilization.

SETTING

Laboratory.

ANIMALS

No animals were utilized in data collection for this study. Two live horses were utilized during the pilot study.

INTERVENTIONS

Application of bandage and splint to a model intended to simulate the bending force on a lower forelimb fracture in a horse

MEASUREMENTS AND MAIN RESULTS

Deflection was determined by the difference between the height of the model's supported free end before application of a 4.5 kg weight and at the conclusion of the deflection test. There was no significant difference in the amount of deflection between bandage/splint combinations (78 ± 32 mm (RJB-1), 94 ± 44 mm (RJB-3), and 93 ± 33 mm (SS)) CONCLUSIONS: The one-layer bandage with splint was equivalent to either RJB configuration in the mean amount of deflection in the simple model of a fracture.