Minimally Invasive Plate Osteosynthesis: Radius and Ulna

Key points

Anatomy of the radius and ulna

The closed reduction techniques and small plate insertion incisions used when performing MIPO do not allow direct observation of the muscles, tendons, fascia layers, and neurovascular structures in the limb segment being stabilized. A thorough knowledge of the anatomy of the antebrachium is essential when performing MIPO to stabilize radial fractures efficiently and with minimal morbidity.

The radius and ulna articulate by means of a proximal radioulnar joint, a distal radioulnar joint, and

Preoperative planning

Careful preoperative planning is critical to facilitate any MIPO procedure. Well-positioned craniocaudal and mediolateral projection radiographs of the fractured and the contralateral antebrachium should be obtained. The radiographs should be scaled to actual size. Computed tomographic (CT) scan of the forelimbs followed by virtual 3-dimensional (3D) reconstruction or 3D printing of the fractured and contralateral radii can also be used to facilitate preoperative surgical planning and plate

Preparation and positioning

In preparation for surgery, the fractured forelimb should be clipped from dorsal midline to digits, and a dirty scrub should be performed in routine fashion. In the operating room, the animal should be positioned in dorsal recumbency with a foam pad under the shoulder of the fractured limb. The fractured limb should be sterilely scrubbed using a hanging limb technique. The limb should be draped so that both the brachium and the antebrachium are in the surgical field to allow intraoperative

Indirect reduction techniques

Indirect reduction refers to the reduction of a fracture by application of distraction forces to fracture segments applied distant from the fracture site. Indirect reduction techniques allow for fracture segment alignment without direct exposure of the fracture.32, 33 Indirect reduction techniques are used when performing MIPO because the fracture site is never exposed. The goals of indirect reduction are to restore the fractured radius to normal length and to properly align the elbow and

Surgical approach

A craniomedial surgical approach, as has been previously described, is most commonly used when performing MIPO of the radius.³⁷ The limb is extended caudally alongside the thorax for the surgical approach. The surgical approach should begin by making the distal plate insertion incision. Digital palpation is combined with flexion of the carpus and, if necessary, insertion of a 25-gauge hypodermic needle to locate the antebrachiocarpal joint. A 2- to 4-cm-long skin incision is made, starting at

Surgical procedure

Limb alignment and fracture reduction should be assessed immediately before plate insertion. Limb alignment can be assessed visually, and the elbow and carpus should be simultaneously flexed and extended to ensure that rotational alignment is correct. Fracture reduction is assessed with intraoperative fluoroscopy, if available, or by digital palpation of the fracture site. Adjustments to alignment and reduction are made if necessary using the previously described techniques. The precontoured

Immediate postoperative care

Postoperative radiographs should be obtained with the animal still anesthetized so that revision surgery can be performed immediately if necessary. The alignment of the elbow and carpal joints as well as apposition at the fracture site and the presence of iatrogenic limb angulation should be assessed on orthogonal view radiographs of the antebrachium. Bone plate positioning on the radius should be assessed, and verification that screws have not been placed in either the carpal or the elbow

Management during the postoperative convalescent period

Dogs and cats are typically hospitalized overnight following MIPO stabilization of a radius and ulna fracture and then discharged the following day. Animals are typically sent home with a 7- to 10-day supply of oral tramadol or oral gabapentin, and dogs are also dispensed a 7- to 10-day course of an oral nonsteroidal anti-inflammatory agent. Some animals are discharged with a 2-week course of oral cephalexin depending on surgeon preference.

The authors do not routinely apply a bandage and splint

Assessment of repair and outcome

Recheck orthopedic examinations and radiographs should be performed at 3 weeks postsurgery and at subsequent 3-week intervals until radiographic evidence of osseous union is obtained. Repeat radiographs are recommended every 3 weeks because in the authors’ experience some radius fractures treated with MIPO are healed in as short a time as 3 weeks and many fractures are healed by 6 weeks.²⁰ Radiographs should consist of craniocaudal and mediolateral projections of the antebrachium. Additional

Summary

MIPO has become an accepted approach to fracture reduction and stabilization, which prioritizes fracture biology and is applicable to many radius and ulna fractures. Appropriate knowledge of antebrachial anatomy and careful preoperative planning are prerequisites for obtaining successful outcomes. The initial technical difficulty associated with the inability to directly observe the fracture segments during surgery tends to decrease as experience and familiarity with the procedure are attained.